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Sample records for negative-index material design

  1. Material parameter retrieval procedure for general bi-isotropic metamaterials and its application to optical chiral negative-index metamaterial design.

    PubMed

    Kwon, Do-Hoon; Werner, Douglas H; Kildishev, Alexander V; Shalaev, Vladimir M

    2008-08-01

    A chiral optical negative-index metamaterial design of doubly periodic construction for the near-infrared spectrum is presented. The chirality is realized by incorporating sub-wavelength planar silver-aluminasilver resonators and arranging them in a left-handed helical (i.e., stair-step) configuration as a wave propagates through the metamaterial. An effective material parameter retrieval procedure is developed for general bi-isotropic metamaterials. A numerical design example is presented and the retrieved effective material parameters exhibiting a negative index of refraction are provided. PMID:18679454

  2. Modulation instability in nonlinear negative-index material.

    PubMed

    Wen, Shuangchun; Wang, Youwen; Su, Wenhua; Xiang, Yuanjiang; Fu, Xiquan; Fan, Dianyuan

    2006-03-01

    We investigate modulation instability (MI) in negative-index material (NIM) with a Kerr nonlinear polarization based on a derived (3+1)-dimensional nonlinear Schrödinger equation for ultrashort pulse propagation. By a standard linear stability analysis, we obtain the expression for instability gain, which unifies the temporal, spatial, and spatiotemporal MI. It is shown that negative refraction not only brings some new features to MI, but also makes MI possible in ordinary material in which it is otherwise impossible. For example, spatial MI can occur in the defocusing regime, while it only occurs in the focusing regime in ordinary material. Spatiotemporal MI can appear in NIM in the case of anomalous dispersion and defocusing nonlinearity, while it cannot appear in ordinary material in the same case. We believe that the difference between the MI in NIM and in ordinary material is due to the fact that negative refraction reverses the sign of the diffraction term, with the signs of dispersion and nonlinearity unchanged. The most notable property of MI in NIM is that it can be manipulated by engineering the self-steepening effect by choosing the size of split-ring resonator circuit elements. To sum up the MI in ordinary material and in NIM, MI may occur for all the combinations of dispersion and nonlinearity. PMID:16605687

  3. Simulations of ferrite-dielectric-wire composite negative index materials.

    PubMed

    Rachford, Frederic J; Armstead, Douglas N; Harris, Vincent G; Vittoria, Carmine

    2007-08-01

    We perform extensive finite difference time domain simulations of ferrite based negative index of refraction composites. A wire grid is employed to provide negative permittivity. The ferrite and wire grid interact to provide both negative and positive index of refraction transmission peaks in the vicinity of the ferrite resonance. Notwithstanding the extreme anisotropy in the index of refraction of the composite, negative refraction is seen at the composite air interface allowing the construction of a focusing concave lens with a magnetically tunable focal length. PMID:17930783

  4. Stability criterion for Gaussian pulse propagation through negative index materials

    SciTech Connect

    Joseph, Ancemma; Porsezian, K.

    2010-02-15

    We analyze the dynamics of propagation of a Gaussian light pulse through a medium having a negative index of refraction employing the recently reported projection operator technique. The governing modified nonlinear Schroedinger equation, obtained by taking into account the Drude dispersive model, is expressed in terms of the parameters of Gaussian pulse, called collective variables, such as width, amplitude, chirp, and phase. This approach yields a system of ordinary differential equations for the evolution of all the pulse parameters. We demonstrate the dependence of stability of the fixed-point solutions of these ordinary differential equations on the linear and nonlinear dispersion parameters. In addition, we validate the analytical approach numerically utilizing the method of split-step Fourier transform.

  5. On the resolution of lenses made of a negative-index material

    SciTech Connect

    Petrin, A B

    2013-09-30

    Resolution of the lenses made of a negative-index material is considered. It is shown that the super-resolution concept is untenable and the possibility of obtaining a perfect image on its own eventually contradicts Maxwell's equations in vacuum. It is also shown that known limitations of the diffraction theory on resolution of optical instruments hold true for the resolution of lenses of a negative-index material, in particular, the resolution of a Veselago lens. (nanogradient dielectric coatings and metamaterials)

  6. Nonlinear excitations in negative index materials: Modulational instability and solitary wave solutions

    NASA Astrophysics Data System (ADS)

    Sharma, Vivek Kumar; Goyal, Amit

    2016-05-01

    We explore the modulational instability and existence of dark, bright solitary wave solutions in negative index-materials (NIMs) modeled by generalized nonlinear Schrödinger equation with competing cubic-quintic and higher-order nonlinearities with dispersive permittivity and permeability. Parameter domains are delineated in which these ultrashort pulses exist in NIMs. Unlike the ordinary materials, these novel excitations occur for different signs of dispersion, Kerr and non-Kerr nonlinearities.

  7. Modulation instability in a triangular three-core coupler with a negative-index material channel

    NASA Astrophysics Data System (ADS)

    Shafeeque Ali, A. K.; Nithyanandan, K.; Porsezian, K.; Maimistov, Andrei I.

    2016-03-01

    A theoretical investigation of the modulation instability (MI) in the three core triangular oppositely directed coupler with negative index material channel is presented. This class of couplers have an effective feedback mechanism due to the opposite directionality of the phase velocities in the negative and positive index channels. It is found that the MI in the nonlinear three core triangular oppositely directed coupler is significantly influenced by the ratio of the forward- to backward-propagating wave power and nonlinearity. Also, in the case of the normal dispersion regime a threshold-like behavior is observed, whereas this behavior is not identified in the anomalous dispersion regime. For the asymmetric case (h\

  8. Influence of birefringence in the instability spectra of oppositely directed coupler with negative index material channel

    NASA Astrophysics Data System (ADS)

    Shafeeque Ali, A. K.; Nithyanandan, K.; Porsezian, K.; Maimistov, Andrei I.

    2016-02-01

    A theoretical investigation on the influence of birefringence in the modulational instability (MI) spectra of an oppositely directed coupler (ODC) with a negative index material (NIM) channel is presented. We study the effect of birefringence on MI in linear and circular birefringent ODCs for both normal and anomalous dispersion regimes. It is found that besides the instability band due to nonlinear positive index material (PIM) and negative index material (NIM) channels, new symmetric instability regions are observed as a result of birefringent effects. Also defocusing nonlinearity suppresses the NIM band in the normal dispersion regime, but in the anomalous dispersion regime the defocusing nonlinearity enhances the gain of the NIM band. In contrast to the case of linear birefringence, in terms of MI gain from circular birefringence, only two birefringent bands dominate: the inherently PIM and NIM bands. This preponderance is attributed to the fact that the cross-phase modulation effect for the case of circular birefringence is stronger, thus allowing a better coupling between the beams, which results in the enhancement of the gain. Therefore, the manipulation of MI and solitons in an ODC is better performed when the birefringence is circular rather than linear. Here we report how to generate and manipulate MI and solitons in birefringent ODCs with a particular emphasis on a NIM channel.

  9. Dispersion, spatial growth rate, and start current of a Cherenkov free-electron laser with negative-index material

    SciTech Connect

    Wang, Yuanyuan; Wei, Yanyu; Jiang, Xuebing; Tang, Xianfeng; Shi, Xianbao; Gong, Yubin; Li, Dazhi; Takano, Keisuke; Nakajima, Makoto; Feng, Jinjun; Miyamoto, Shuji

    2015-08-15

    We present an analysis of a Cherenkov free-electron laser based on a single slab made from negative-index materials. In this system, a flat electron beam with finite thickness travelling close to the surface of the slab interacts with the copropagating electromagnetic surface mode. The dispersion equation for a finitely thick slab is worked out and solved numerically to study the dispersion relation of surface modes supported by negative-index materials, and the calculations are in good agreement with the simulation results from a finite difference time domain code. We find that under suitable conditions there is inherent feedback in such a scheme due to the characteristics of negative-index materials, which means that the system can oscillate without external reflectors when the beam current exceeds a threshold value, i.e., start current. Using the hydrodynamic approach, we setup coupled equations for this system, and solve these equations analytically in the small signal regime to obtain formulas for the spatial growth rate and start current.

  10. Generalized nonlinear Schrödinger equation for dispersive susceptibility and permeability: application to negative index materials.

    PubMed

    Scalora, Michael; Syrchin, Maxim S; Akozbek, Neset; Poliakov, Evgeni Y; D'Aguanno, Giuseppe; Mattiucci, Nadia; Bloemer, Mark J; Zheltikov, Aleksei M

    2005-07-01

    A new generalized nonlinear Schrödinger equation describing the propagation of ultrashort pulses in bulk media exhibiting frequency dependent dielectric susceptibility and magnetic permeability is derived and used to characterize wave propagation in a negative index material. The equation has new features that are distinct from ordinary materials (mu=1): the linear and nonlinear coefficients can be tailored through the linear properties of the medium to attain any combination of signs unachievable in ordinary matter, with significant potential to realize a wide class of solitary waves. PMID:16090616

  11. Properties of Defect Modes in Periodic Lossy Multilayer with Negative-Index-Materials

    NASA Astrophysics Data System (ADS)

    Alireza, Aghajamali; Mahmood, Barati

    2013-07-01

    Employing the characteristic matrix method, this study investigates transmission properties of one-dimensional defective lossy photonic crystals composed of negative and positive refractive index layers with one lossless defect layer at the center of the crystal. The results of the study show that as the refractive index and thickness of the defect layer increase, the frequency of the defect mode decreases. In addition, the study shows that the frequency of the defect mode is sensitive to the incidence angle, polarization, and physical properties of the defect layer, but it is insensitive to the small lattice loss factor. The peak of the defect mode is very sensitive to the loss factor, incidence angle, polarization, refractive index, and thickness of the defect layer. This study also shows that the peak and the width of the defect mode are affected by the numbers of the lattice period and the loss factor. The results can lead to designing new types of narrow filter structures and other optical devices.

  12. Focus modulation of cylindrical vector beams through negative-index grating lenses

    NASA Astrophysics Data System (ADS)

    Wang, Shengming; Xu, Ji; Zhong, Yi; Ren, Rong; Lu, Yunqing; Wan, Hongdan; Wang, Jin; Ding, Jianping

    2016-08-01

    A cylindrically symmetric negative-index grating lens composed of unitary material is proposed as an effective method to modulate the focusing of cylindrical vector beams (CVBs). The grating parameters are designed to obtain an appropriate negative index, and the lens profile is tailored to realize the constructive interference. The plano-concave lens is parameterized to achieve desired focal length and the plano-cone lens is proposed to obtain large depth of focus. An optical needle is generated with radially polarized incidence, and an optical tube is achieved with incidence of azimuthal polarization. Moreover, the presented modulation methods can be applied for any arbitrary polarized CVBs. This work offers a more flexible and effective approach to design negative-index lenses for subwavelength focusing of CVBs, which has potential application value in related areas, such as optical trapping, and other nano-optics fields.

  13. Structures with negative index of refraction

    DOEpatents

    Soukoulis, Costas M.; Zhou, Jiangfeng; Koschny, Thomas; Zhang, Lei; Tuttle, Gary

    2011-11-08

    The invention provides simplified negative index materials (NIMs) using wire-pair structures, 4-gap single ring split-ring resonator (SRR), fishnet structures and overleaf capacitor SRR. In the wire-pair arrangement, a pair of short parallel wires and continuous wires are used. In the 4-gap single-ring SRR, the SRRs are centered on the faces of a cubic unit cell combined with a continuous wire type resonator. Combining both elements creates a frequency band where the metamaterial is transparent with simultaneously negative .di-elect cons. and .mu.. In the fishnet structure, a metallic mesh on both sides of the dielectric spacer is used. The overleaf capacitor SRR changes the gap capacities to small plate capacitors by making the sections of the SRR ring overlap at the gaps separated by a thin dielectric film. This technique is applicable to conventional SRR gaps but it best deploys for the 4-gap single-ring structures.

  14. Tamm plasmon-polariton with negative group velocity induced by a negative index meta-material capping layer at metal-Bragg reflector interface.

    PubMed

    Liu, Cunding; Kong, Mingdong; Li, Bincheng

    2014-05-01

    Influence of a negative refractive index meta-material (NIM) capping layer on properties of Tamm plasmon-polariton at the interface of metal-Bragg reflector structure is investigated. Conditions for excitation of the plasmon-polariton is determined from reflectivity mapping calculation and analyzed with cavity mode theory. For specific thicknesses of capping layers, Tamm plasmon-polariton with negative group velocity is revealed in a wide region of frequency. Different from backward optical propagation induced by negative effective-group-refractive-index in dispersive media, negative group velocity of Tamm plasmon-polariton results from opposite signs of cross-section-integrated field energy and Poynting vector. PMID:24921834

  15. Fano-like resonances in split concentric nanoshell dimers in designing negative-index metamaterials for biological-chemical sensing and spectroscopic purposes.

    PubMed

    Ahmadivand, Arash; Karabiyik, Mustafa; Pala, Nezih

    2015-05-01

    In this study, we investigated numerically the plasmon response of a dimer configuration composed of a couple of split and concentric Au nanoshells in a complex orientation. We showed that an isolated composition of two concentric split nanoshells could be tailored to support strong plasmon resonant modes in the visible wavelengths. After determining the accurate geometric dimensions for the presented antisymmetric nanostructure, we designed a dimer array that shows complex behavior during exposure to different incident polarizations. We verified that the examined dimer was able to support destructive interference between dark and bright plasmon modes, which resulted in a pronounced Fano-like dip. Observation of a Fano minimum in such a simple molecular orientation of subwavelength particles opens new avenues for employing this structure in designing various practical plasmonic devices. Depositing the final dimer in a strong coupling condition on a semiconductor metasurface and measuring the effective refractive index at certain wavelengths, we demonstrate that each one of dimer units can be considered a meta-atom due to the high aspect ratio in the geometric parameters. Using this method, by extending the number of dimers periodically and illuminating the structure, we examined the isotropic, polarization-dependent, and transmission behavior of the metamaterial configuration. Using numerical methods and calculating the effective refractive indices, we computed and sketched corresponding figure of merit over the transmission window, where the maximum value obtained was 42.3 for Si and 54.6 for gallium phosphide (GaP) substrates. PMID:25811974

  16. Negative-Index Metamaterials in the Visible Range

    NASA Astrophysics Data System (ADS)

    Shalaev, Vladimir

    2007-03-01

    In conventional materials, out of the two field components of light, electric and magnetic, only the electric one (``electric hand'') efficiently couples to and probes the atoms of a material while its ``magnetic hand'' remains almost unused because the interaction of atoms with the magnetic filed component of light is normally very week. Metamaterials, i.e. artificial materials with rationally designed properties, can enable the coupling of both field components of light to meta-atoms, enabling entirely new optical properties and exciting applications with such ``two-handed'' light. Metamaterials are expected to open a gateway to unprecedented electromagnetic properties and functionality unattainable from naturally occurring materials. Negative-refractive index metamaterials create entirely new prospects for guiding light on the nanoscale, some of which may have revolutionary impact on present-day optical technologies. The extraordinary nonlinear optical properties of negative-index metamaterials are also discussed. We review this new emerging field of metamaterials and recent progress in demonstrating a negative refractive index in the optical and visible range, where applications can be particularly important, including sub-wavelength imaging and cloaking objects, i.e. making them invisible.

  17. Direct observation of negative-index microwave surface waves.

    PubMed

    Dockrey, J A; Horsley, S A R; Hooper, I R; Sambles, J R; Hibbins, A P

    2016-01-01

    Waves propagating in a negative-index material have wave-front propagation (wavevector, k) opposite in direction to that of energy flow (Poynting vector, S). Here we present an experimental realisation at microwave frequencies of an analogous surface wave phenomenon whereby a metasurface supports a surface mode that has two possible wavevector eigenstates within a narrow band of frequencies: one that supports surface waves with positive mode index, and another that supports surface waves with negative mode index. Phase sensitive measurements of the near-field of surface waves across the metasurface show the contrasting spatial evolution of the two eigenstates, providing a unique opportunity to directly observe the negative-index phenomenon. PMID:26903284

  18. Direct observation of negative-index microwave surface waves

    NASA Astrophysics Data System (ADS)

    Dockrey, J. A.; Horsley, S. A. R.; Hooper, I. R.; Sambles, J. R.; Hibbins, A. P.

    2016-02-01

    Waves propagating in a negative-index material have wave-front propagation (wavevector, k) opposite in direction to that of energy flow (Poynting vector, S). Here we present an experimental realisation at microwave frequencies of an analogous surface wave phenomenon whereby a metasurface supports a surface mode that has two possible wavevector eigenstates within a narrow band of frequencies: one that supports surface waves with positive mode index, and another that supports surface waves with negative mode index. Phase sensitive measurements of the near-field of surface waves across the metasurface show the contrasting spatial evolution of the two eigenstates, providing a unique opportunity to directly observe the negative-index phenomenon.

  19. Direct observation of negative-index microwave surface waves

    PubMed Central

    Dockrey, J. A.; Horsley, S. A. R.; Hooper, I. R.; Sambles, J. R.; Hibbins, A. P.

    2016-01-01

    Waves propagating in a negative-index material have wave-front propagation (wavevector, k) opposite in direction to that of energy flow (Poynting vector, S). Here we present an experimental realisation at microwave frequencies of an analogous surface wave phenomenon whereby a metasurface supports a surface mode that has two possible wavevector eigenstates within a narrow band of frequencies: one that supports surface waves with positive mode index, and another that supports surface waves with negative mode index. Phase sensitive measurements of the near-field of surface waves across the metasurface show the contrasting spatial evolution of the two eigenstates, providing a unique opportunity to directly observe the negative-index phenomenon. PMID:26903284

  20. Gap solitons in a nonlinear quadratic negative-index cavity.

    PubMed

    Scalora, Michael; de Ceglia, Domenico; D'Aguanno, Giuseppe; Mattiucci, Nadia; Akozbek, Neset; Centini, Marco; Bloemer, Mark J

    2007-06-01

    We predict the existence of gap solitons in a nonlinear, quadratic Fabry-Pérot negative index cavity. A peculiarity of a single negative index layer is that if magnetic and electric plasma frequencies are different it forms a photonic band structure similar to that of a multilayer stack composed of ordinary, positive index materials. This similarity also results in comparable field localization and enhancement properties that under appropriate conditions may be used to either dynamically shift the band edge, or for efficient energy conversion. We thus report that an intense, fundamental pump pulse is able to shift the band edge of a negative index cavity, and make it possible for a weak second harmonic pulse initially tuned inside the gap to be transmitted, giving rise to a gap soliton. The process is due to cascading, a well-known phenomenon that occurs far from phase matching conditions that limits energy conversion rates, it resembles a nonlinear third-order process, and causes pulse compression due to self-phase modulation. The symmetry of the equations of motion under the action of either an electric or a magnetic nonlinearity suggests that both nonlinear polarization and magnetization, or a combination of both, can lead to solitonlike pulses. More specifically, the antisymmetric localization properties of the electric and magnetic fields cause a nonlinear polarization to generate a dark soliton, while a nonlinear magnetization spawns a bright soliton. PMID:17677375

  1. Low-loss negative index metamaterials for X, Ku, and K microwave bands

    SciTech Connect

    Lee, David A.; Vedral, L. James; Smith, David A.; Pinchuk, Anatoliy O.; Musselman, Randall L.

    2015-04-15

    Low-loss, negative-index of refraction metamaterials were designed and tested for X, Ku, and K microwave frequency bands. An S-shaped, split-ring resonator was used as a unit cell to design homogeneous slabs of negative-index metamaterials. Then, the slabs of metamaterials were cut unto prisms to measure experimentally the negative index of refraction of a plane electromagnetic wave. Theoretical simulations using High-Frequency Structural Simulator, a finite element equation solver, were in good agreement with experimental measurements. The negative index of refraction was retrieved from the angle- and frequency-dependence of the transmitted intensity of the microwave beam through the metamaterial prism and compared well to simulations; in addition, near-field electromagnetic intensity mapping was conducted with an infrared camera, and there was also a good match with the simulations for expected frequency ranges for the negative index of refraction.

  2. Low-loss multilayered metamaterial exhibiting a negative index of refraction at visible wavelengths

    NASA Astrophysics Data System (ADS)

    Garcia-Meca, Carlos

    2012-02-01

    Over the last decade, metamaterials have attracted a great interest thanks to their potential to expand the range of electromagnetic properties found in natural materials. In particular, the possibility of achieving negative refractive index media (NIM) enables us to implement superlenses and optical storing devices. Since the first experimental demonstration at microwave frequencies, much effort has been put in extending negative refraction to the visible spectrum, where we can take full advantage of NIM properties. For instance, the superior imaging ability of NIM would be essential for visible microscopy. The desired features for NIM are low loss and isotropy. This last property includes polarization independence and negative-index behavior in all spatial directions. None of these features have been attained in previous experiments. Thus, the current challenge is to improve such aspects in order to make NIM suitable for practical applications. In this work, we experimentally demonstrate a low-loss multilayer metamaterial exhibiting a double-negative index in the visible spectrum, while presenting polarization independence at normal incidence. This has been achieved by exploiting the properties of a second-order magnetic resonance of the so-called fishnet structure, in contrast to previous works that used first-order magnetic resonances, both related to gap surface plasmon polariton (SPP) modes. The low-loss nature of the employed magnetic resonance, together with the effect of the interacting adjacent layers, results in a figure of merit as high as 3.34. A wide spectral range of negative index is achieved, covering the wavelength region between 620 and 806 nm with only two different designs. The fabricated metamaterials are the first experimental multilayer NIM in the visible spectrum, which entails an important step towards homogeneous NIM in this range. Finally, we found that the SPP modes determining the permeability resonance display weak angular dispersion.

  3. A single-layer wide-angle negative-index metamaterial at visible freque

    SciTech Connect

    Burgos, Stanley P.; de Waele, Rene; Polman, Albert; Atwater, Harry A.

    2010-04-18

    Metamaterials are materials with artificial electromagnetic properties defined by their sub-wavelength structure rather than their chemical composition. Negative-index materials (NIMs) are a special class of metamaterials characterized by an effective negative index that gives rise to such unusual wave behaviour as backwards phase propagation and negative refraction. These extraordinary properties lead to many interesting functions such as sub-diffraction imaging and invisibility cloaking. So far, NIMs have been realized through layering of resonant structures, such as split-ring resonators, and have been demonstrated at microwave to infrared frequencies over a narrow range of angles-of-incidence and polarization. However, resonant-element NIM designs suffer from the limitations of not being scalable to operate at visible frequencies because of intrinsic fabrication limitations, require multiple functional layers to achieve strong scattering and have refractive indices that are highly dependent on angle of incidence and polarization. Here we report a metamaterial composed of a single layer of coupled plasmonic coaxial waveguides that exhibits an effective refractive index of -2 in the blue spectral region with a figure-of-merit larger than 8. The resulting NIM refractive index is insensitive to both polarization and angle-of-incidence over a ±50° angular range, yielding a wide-angle NIM at visible frequencies.

  4. A single-layer wide-angle negative-index metamaterial at visible frequencies.

    PubMed

    Burgos, Stanley P; de Waele, Rene; Polman, Albert; Atwater, Harry A

    2010-05-01

    Metamaterials are materials with artificial electromagnetic properties defined by their sub-wavelength structure rather than their chemical composition. Negative-index materials (NIMs) are a special class of metamaterials characterized by an effective negative index that gives rise to such unusual wave behaviour as backwards phase propagation and negative refraction. These extraordinary properties lead to many interesting functions such as sub-diffraction imaging and invisibility cloaking. So far, NIMs have been realized through layering of resonant structures, such as split-ring resonators, and have been demonstrated at microwave to infrared frequencies over a narrow range of angles-of-incidence and polarization. However, resonant-element NIM designs suffer from the limitations of not being scalable to operate at visible frequencies because of intrinsic fabrication limitations, require multiple functional layers to achieve strong scattering and have refractive indices that are highly dependent on angle of incidence and polarization. Here we report a metamaterial composed of a single layer of coupled plasmonic coaxial waveguides that exhibits an effective refractive index of -2 in the blue spectral region with a figure-of-merit larger than 8. The resulting NIM refractive index is insensitive to both polarization and angle-of-incidence over a +/-50 degree angular range, yielding a wide-angle NIM at visible frequencies. PMID:20400955

  5. Microwave Propagation in Negative Index and Artificial Dielectric Media

    NASA Astrophysics Data System (ADS)

    Parimi, Patanjali; Vodo, Plarenta; Lu, Wentao; Sridhar, Srinivas

    2003-03-01

    Negative index media (NIM) are fabricated by interleaving arrays of split ring resonators and wire strips. Microwave (X-band) waveguide measurements on the NIM yield quantitative information on the material parameters, % tilden(ω)=n^' +in^' ', tilde\\varepsilon% (ω )=\\varepsilon ^' +i\\varepsilon ^' ' and tilde% μ(ω )=μ ^' +iμ ^' ' . Typical NIM features such as passband in the NIM region expected from the theoretical analysis are observed in the measured data. The n^'(ω) determined from the waveguide transmission parameters (tildeS_11,tildeS_21) is found to vary from -4.8 to-0.3 in the passband region 9.6-10.5GHz. The results show that transmission is optimized for n^' (ω ) -1 and low n^' ' . A detailed investigation of several NIM materials suggests that the characteristic properties of the NIM are dependent on the length of the material, choice of the substrate material, and continuity in the wire strips. Artificial dielectric media fabricated with arrays of wire strips exhibit a characteristic microwave plasmon mode in the X-band region, below which \\varepsilon ^' (ω )<0. Work supported by the National Science Foundation and the Air Force Research Labs, Hanscom.

  6. Sub-picosecond optical switching with a negative index metamaterial

    SciTech Connect

    Dani, Keshav M; Upadhya, Prashant C; Zahyum, Ku

    2009-01-01

    Development of all-optical signal processing, eliminating the performance and cost penalties of optical-electrical-optical conversion, is important for continu,ing advances in Terabits/sec (Tb/s) communications.' Optical nonlinearities are generally weak, traditionally requiring long-path, large-area devicesl,2 or very high-Q, narrow-band resonator structures.3 Optical metamaterials offer unique capabilities for optical-optical interactions. Here we report 600 femtosecond (fs) all-optical modulation using a fIShnet (2D-perforated metallamorphous-Si (a-Si)/metal film stack) negative-index meta material with a structurally tunable broad-band response near 1.2 {micro}m. Over 20% modulation (experimentally limited) is achieved in a path length of only 116 nm by photo-excitation of carriers in the a-Si layer. This has the potential for Tb/s aU-optical communication and will lead to other novel, compact, tunable sub-picosecond (ps) photonic devices.

  7. Symmetry breaking and optical negative index of closed nanorings

    NASA Astrophysics Data System (ADS)

    Kanté, Boubacar; Park, Yong-Shik; O'Brien, Kevin; Shuldman, Daniel; Lanzillotti-Kimura, Norberto D.; Jing Wong, Zi; Yin, Xiaobo; Zhang, Xiang

    2012-11-01

    Metamaterials have extraordinary abilities, such as imaging beyond the diffraction limit and invisibility. Many metamaterials are based on split-ring structures, however, like atomic orbital currents, it has long been believed that closed rings cannot produce negative refractive index. Here we report a low-loss and polarization-independent negative-index metamaterial made solely of closed metallic nanorings. Using symmetry breaking that negatively couples the discrete nanorings, we measured negative phase delay in our composite ‘chess metamaterial’. The formation of an ultra-broad Fano-resonance-induced optical negative-index band, spanning wavelengths from 1.3 to 2.3 μm, is experimentally observed in this structure. This discrete and mono-particle negative-index approach opens exciting avenues towards symmetry-controlled topological nanophotonics with on-demand linear and nonlinear responses.

  8. Symmetry Breaking and Optical Negative Index of Closed Nanorings

    NASA Astrophysics Data System (ADS)

    Kante, Boubacar; Park, Yong-Shik; O'Brien, Kevin; Shuldman, Daniel; Lanzillotti-Kimura, Norberto; Wong, Zi; Yin, Xiaobo; Zhang, Xiang; UC Berkeley Team

    2013-03-01

    We report the first experimental demonstration of broadband negative-index metamaterial made solely of closed metallic nanorings. Using symmetry breaking that negatively couples the discrete nanorings, we measured negative phase delay in our composite chess metamaterial. Our approach open avenues towards topological nanophotonics with on demand linear and non-linear responses.

  9. Modulation instability of structured-light beams in negative-index metamaterials

    NASA Astrophysics Data System (ADS)

    Silahli, Salih Z.; Walasik, Wiktor; Litchinitser, Natalia M.

    2016-05-01

    One of the most fundamental properties of isotropic negative-index metamaterials (NIMs), namely opposite directionality of the Poynting vector and the wavevector, enable many novel linear and nonlinear regimes of light–matter interactions. Here, we predict distinct characteristics of azimuthal modulation instability (MI) of optical vortices with different topological charges in NIMs with Kerr-type and saturable nonlinearity. We derive an analytical expression for the spatial modulation-instability gain for the Kerr-nonlinearity case and show that a specific condition relating the diffraction and the nonlinear lengths must be fulfilled for the azimuthal MI to occur. Finally, we investigate the rotation of the necklace beams due to the transfer of orbital angular momentum of the generating vortex on the movement of solitary necklace beams. We show that the direction of rotation is opposite in positive- and negative-index materials.

  10. Large-area flexible 3D optical negative index metamaterial formed by nanotransfer printing

    NASA Astrophysics Data System (ADS)

    Chanda, Debashis; Shigeta, Kazuki; Gupta, Sidhartha; Cain, Tyler; Carlson, Andrew; Mihi, Agustin; Baca, Alfred J.; Bogart, Gregory R.; Braun, Paul; Rogers, John A.

    2011-07-01

    Negative-index metamaterials (NIMs) are engineered structures with optical properties that cannot be obtained in naturally occurring materials. Recent work has demonstrated that focused ion beam and layer-by-layer electron-beam lithography can be used to pattern the necessary nanoscale features over small areas (hundreds of µm2) for metamaterials with three-dimensional layouts and interesting characteristics, including negative-index behaviour in the optical regime. A key challenge is in the fabrication of such three-dimensional NIMs with sizes and at throughputs necessary for many realistic applications (including lenses, resonators and other photonic components). We report a simple printing approach capable of forming large-area, high-quality NIMs with three-dimensional, multilayer formats. Here, a silicon wafer with deep, nanoscale patterns of surface relief serves as a reusable stamp. Blanket deposition of alternating layers of silver and magnesium fluoride onto such a stamp represents a process for `inking' it with thick, multilayer assemblies. Transfer printing this ink material onto rigid or flexible substrates completes the fabrication in a high-throughput manner. Experimental measurements and simulation results show that macroscale, three-dimensional NIMs (>75 cm2) nano-manufactured in this way exhibit a strong, negative index of refraction in the near-infrared spectral range, with excellent figures of merit.

  11. All-semiconductor negative-index plasmonic absorbers.

    PubMed

    Law, S; Roberts, C; Kilpatrick, T; Yu, L; Ribaudo, T; Shaner, E A; Podolskiy, V; Wasserman, D

    2014-01-10

    We demonstrate epitaxially grown all-semiconductor thin-film midinfrared plasmonic absorbers and show that absorption in these structures is linked to the excitation of highly confined negative-index surface plasmon polaritons. Strong (>98%) absorption is experimentally observed, and the spectral position and intensity of the absorption resonances are studied by reflection and transmission spectroscopy. Numerical models as well as an analytical description of the excited guided modes in our structures are presented, showing agreement with experiment. The structures investigated demonstrate a wavelength-flexible, all-semiconductor, plasmonic architecture with potential for both sensing applications and enhanced interaction of midinfrared radiation with integrated semiconductor optoelectronic elements. PMID:24483930

  12. Tunable negative-index photonic crystals using colloidal magnetic fluids

    NASA Astrophysics Data System (ADS)

    Geng, Tao; Wang, Xin; Wang, Yan; Dong, Xiang-Mei

    2015-12-01

    The model of using colloidal magnetic fluid to build tunable negative-index photonic crystal is established. The effective permittivity ɛe and permeability μe of the two-dimensional photonic crystal are investigated in detail. For transverse magnetic polarization, both ɛe and μe exhibit a Lorentz-type anomalous dispersion, leading to a region where ɛe and μe are simultaneously negative. Then, considering a practical case, in which the thickness of photonic crystal is finite, the band structures for odd modes are calculated by the plane wave expansion method and the finite-difference time-domain method. The results suggest that reducing the external magnetic field strength or slab thickness will weaken the periodic modulation strength of the photonic crystal. Simulation results prove that the negative-index can be tuned by varying the external magnetic field strength or the slab thickness. The work presented in this paper gives a guideline for realizing the flat photonic crystal lens with tunable properties at optical frequencies, which may have potential applications in tunable near-field imaging systems. Project supported by the National Basic Research Program of China (Grant No. 2015CB352001), the Shanghai Rising-Star Program, China (Grant No. 12QA1402300), the China Scholarship Council (CSC) Program, and the Basic Research Program of Shanghai, China (Grant No. 14ZR1428500).

  13. Intra-connected three-dimensionally isotropic bulk negative index photonic metamaterial

    SciTech Connect

    Guney, Durdu; Koschny, Thomas; Soukoulis, Costas

    2010-05-26

    Isotropic negative index metamaterials (NIMs) are highly desired, particularly for the realization of ultra-high resolution lenses. However, existing isotropic NIMs function only two-dimensionally and cannot be miniaturized beyond microwaves. Direct laser writing processes can be a paradigm shift toward the fabrication of three-dimensionally (3D) isotropic bulk optical metamaterials, but only at the expense of an additional design constraint, namely connectivity. Here, we demonstrate with a proof-of-principle design that the requirement connectivity does not preclude fully isotropic left-handed behavior. This is an important step towards the realization of bulk 3D isotropic NIMs at optical wavelengths.

  14. Natural media with negative index of refraction: Perspectives of complex transition metal oxides (Review Article)

    NASA Astrophysics Data System (ADS)

    Fertman, E. L.; Beznosov, A. B.

    2011-07-01

    The capabilities of perovskite-like compounds with the effect of colossal magnetoresistance (CMR) and some other complex oxides to have a negative index of refraction (NIR) are considered. Physical properties of these compounds are also analyzed from the standpoint of designing tunable metamaterials on their base. Of particular interest are temperature and magnetic field driven first-order transformations in oxides with perovskite structure and in spinels. These transformations give rise to nanophase separated states, using which the properties of negative refraction can be affected. The magnetic-field controlled metamaterials with CMR oxides as a boundary NIR media for a photonic crystal are discussed.

  15. Three-dimensional negative index of refraction at optical frequencies by coupling plasmonic waveguides.

    PubMed

    Verhagen, Ewold; de Waele, René; Kuipers, L; Polman, Albert

    2010-11-26

    We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. Control of waveguide coupling yields a metamaterial consisting of a one-dimensional multilayer stack that exhibits an isotropic index of -1 at a free-space wavelength of 400 nm. The concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency. PMID:21231386

  16. Three-Dimensional Negative Index of Refraction at Optical Frequencies by Coupling Plasmonic Waveguides

    NASA Astrophysics Data System (ADS)

    Verhagen, Ewold; de Waele, René; Kuipers, L.; Polman, Albert

    2010-11-01

    We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. Control of waveguide coupling yields a metamaterial consisting of a one-dimensional multilayer stack that exhibits an isotropic index of -1 at a free-space wavelength of 400 nm. The concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency.

  17. Biological materials by design.

    PubMed

    Qin, Zhao; Dimas, Leon; Adler, David; Bratzel, Graham; Buehler, Markus J

    2014-02-19

    In this topical review we discuss recent advances in the use of physical insight into the way biological materials function, to design novel engineered materials 'from scratch', or from the level of fundamental building blocks upwards and by using computational multiscale methods that link chemistry to material function. We present studies that connect advances in multiscale hierarchical material structuring with material synthesis and testing, review case studies of wood and other biological materials, and illustrate how engineered fiber composites and bulk materials are designed, modeled, and then synthesized and tested experimentally. The integration of experiment and simulation in multiscale design opens new avenues to explore the physics of materials from a fundamental perspective, and using complementary strengths from models and empirical techniques. Recent developments in this field illustrate a new paradigm by which complex material functionality is achieved through hierarchical structuring in spite of simple material constituents. PMID:24451343

  18. Negative index of refraction in a four-level system with magnetoelectric cross coupling and local field corrections

    SciTech Connect

    Bello, F.

    2011-07-15

    This research focuses on a coherently driven four-level atomic medium with the aim of inducing a negative index of refraction while taking into consideration local field corrections as well as magnetoelectric cross coupling (i.e.,chirality) within the material's response functions. Two control fields are used to render the medium transparent for a probe field which simultaneously couples to an electric and a magnetic dipole transition, thus allowing one to test the permittivity and permeability of the material at the same time. Numerical simulations show that a negative index of refraction with low absorption can be obtained for a range of probe detunings while depending on number density and the ratio between the intensities of the control fields.

  19. Ultra low-loss, isotropic optical negative-index metamaterial based on hybrid metal-semiconductor nanowires

    PubMed Central

    Paniagua-Domínguez, R.; Abujetas, D. R.; Sánchez-Gil, J. A.

    2013-01-01

    Recently, many fascinating properties predicted for metamaterials (negative refraction, superlensing, electromagnetic cloaking,…) were experimentally demonstrated. Unfortunately, the best achievements have no direct translation to the optical domain, without being burdened by technological and conceptual difficulties. Of particular importance within the realm of optical negative-index metamaterials (NIM), is the issue of simultaneously achieving strong electric and magnetic responses and low associated losses. Here, hybrid metal-semiconductor nanowires are proposed as building blocks of optical NIMs. The metamaterial thus obtained, highly isotropic in the plane normal to the nanowires, presents a negative index of refraction in the near-infrared, with values of the real part well below −1, and extremely low losses (an order of magnitude better than present optical NIMs). Tunability of the system allows to select the operating range in the whole telecom spectrum. The design is proven in configurations such as prisms and slabs, directly observing negative refraction. PMID:23514968

  20. Design a Sculpting Material

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2011-01-01

    Artists have used a variety of materials over the years for sculpting. They have been quick to use unusual pieces of technology to make a vibrant and unique statement, just as painters have created and used a wide variety of colors and derived pigments for their canvases. In this article, the author discusses a design challenge that gives students…

  1. Soft 3D acoustic metamaterial with negative index.

    PubMed

    Brunet, Thomas; Merlin, Aurore; Mascaro, Benoit; Zimny, Kevin; Leng, Jacques; Poncelet, Olivier; Aristégui, Christophe; Mondain-Monval, Olivier

    2015-04-01

    Many efforts have been devoted to the design and achievement of negative-refractive-index metamaterials since the 2000s. One of the challenges at present is to extend that field beyond electromagnetism by realizing three-dimensional (3D) media with negative acoustic indices. We report a new class of locally resonant ultrasonic metafluids consisting of a concentrated suspension of macroporous microbeads engineered using soft-matter techniques. The propagation of Gaussian pulses within these random distributions of 'ultra-slow' Mie resonators is investigated through in situ ultrasonic experiments. The real part of the acoustic index is shown to be negative (up to almost - 1) over broad frequency bandwidths, depending on the volume fraction of the microbeads as predicted by multiple-scattering calculations. These soft 3D acoustic metamaterials open the way for key applications such as sub-wavelength imaging and transformation acoustics, which require the production of acoustic devices with negative or zero-valued indices. PMID:25502100

  2. Looking for design in materials design.

    PubMed

    Eberhart, M E; Clougherty, D P

    2004-10-01

    Despite great advances in computation, materials design is still science fiction. The construction of structure-property relations on the quantum scale will turn computational empiricism into true design. PMID:15467684

  3. Looking for design in materials design

    NASA Astrophysics Data System (ADS)

    Eberhart, M. E.; Clougherty, D. P.

    2004-10-01

    Despite great advances in computation, materials design is still science fiction. The construction of structure-property relations on the quantum scale will turn computational empiricism into true design.

  4. Negative-index gratings formed by femtosecond laser overexposure and thermal regeneration

    PubMed Central

    He, Jun; Wang, Yiping; Liao, Changrui; Wang, Chao; Liu, Shen; Yang, Kaiming; Wang, Ying; Yuan, Xiaocong; Wang, Guo Ping; Zhang, Wenjing

    2016-01-01

    We demonstrate a method for the preparation of negative-index fibre Bragg gratings (FBGs) using 800 nm femtosecond laser overexposure and thermal regeneration. A positive-index type I-IR FBG was first inscribed in H2-free single-mode fibre using a femtosecond laser directed through a phase mask, and then a highly polarization dependant phase-shifted FBG (P-PSFBG) was fabricated from the type I-IR FBG by overexposure to the femtosecond laser. Subsequently, the P-PSFBG was thermally annealed at 800 °C for 12 hours. Grating regeneration was observed during thermal annealing, and a negative-index FBG was finally obtained with a high reflectivity of 99.22%, an ultra-low insertion loss of 0.08 dB, a blueshift of 0.83 nm in the Bragg wavelength, and an operating temperature of up to 1000 °C for more than 10 hours. Further annealing tests showed that the thermal stability of the negative-index FBG was lower than that of a type II-IR FBG, but much higher than that of a type I-IR FBG. Moreover, the formation of such a negative-index grating may result from thermally regenerated type IIA photosensitivity. PMID:26979090

  5. Two-dimensional fluid-filled closed-cell cellular solid as an acoustic metamaterial with negative index

    NASA Astrophysics Data System (ADS)

    Dorodnitsyn, V.; Van Damme, B.

    2016-04-01

    A concept for acoustic metamaterials consisting of a cellular medium with fluid-filled cells is fabricated and studied experimentally. In such a system, the fluid and solid structure explicitly interact, and elastic wave propagation is coupled to both phases. Focusing here on shear wave behavior, we confirm previous numerical studies in three steps. We first measure the material deformations pertaining to three qualitatively different shear wave modes in the frequency range below 3.5 kHz. We then measure the group velocity and demonstrate that, within a certain frequency interval, the group and phase velocity have opposite signs. This shows that the system acts as a negative-index metamaterial. Finally, we confirm the presence of band gaps due to the locally resonant behavior of the cell walls. The demonstrated concept of a closed, fluid-filled cellular material as an acoustic metamaterial opens a wide space for applications.

  6. Specific absorption rate analysis of broadband mobile antenna with negative index metamaterial

    NASA Astrophysics Data System (ADS)

    Alam, Touhidul; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2016-03-01

    This paper presents a negative index metamaterial-inspired printed mobile wireless antenna that can support most mobile applications such as GSM, UMTS, Bluetooth and WLAN frequency bands. The antenna consists of a semi-circular patch, a 50Ω microstrip feed line and metamaterial ground plane. The antenna occupies a very small space of 37 × 47 × 0.508 mm3, making it suitable for mobile wireless application. The perceptible novelty shown in this proposed antenna is that reduction of specific absorption rate using the negative index metamaterial ground plane. The proposed antenna reduced 72.11 and 75.53 % of specific absorption rate at 1.8 and 2.4 GHz, respectively.

  7. Materials design for new superconductors

    NASA Astrophysics Data System (ADS)

    Norman, M. R.

    2016-07-01

    Since the announcement in 2011 of the Materials Genome Initiative by the Obama administration, much attention has been given to the subject of materials design to accelerate the discovery of new materials that could have technological implications. Although having its biggest impact for more applied materials like batteries, there is increasing interest in applying these ideas to predict new superconductors. This is obviously a challenge, given that superconductivity is a many body phenomenon, with whole classes of known superconductors lacking a quantitative theory. Given this caveat, various efforts to formulate materials design principles for superconductors are reviewed here, with a focus on surveying the periodic table in an attempt to identify cuprate analogues.

  8. Materials by Design

    NASA Astrophysics Data System (ADS)

    Olson, Gregory B.

    As a new millennium unfolds, a Science Age of three centuries draws to a close, replaced by a Technology Age based not in scientific discovery but in a revolution in engineering design led by U.S. industry. The resulting New Economy, which we now strive to sustain, is based in technology not found in a laboratory, but deliberately created from the human mind in response to perceived needs. While we tend to be nostalgic about exploration ages, at this point in history humankind not only enjoys an unprecedented ability to create wealth from thought, but holds all the tools for a much-needed transformation from mere technology to responsible technology.

  9. A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications

    PubMed Central

    Islam, Mohammad Tariqul; Islam, Md. Moinul; Samsuzzaman, Md.; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah

    2015-01-01

    This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2) covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors. PMID:26007721

  10. A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications.

    PubMed

    Islam, Mohammad Tariqul; Islam, Md Moinul; Samsuzzaman, Md; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah

    2015-01-01

    This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2) covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors. PMID:26007721

  11. Triangular lattice of carbon nanotube arrays for negative index of refraction and subwavelength lensing effect

    SciTech Connect

    Wang, Y.; Wang, X.; Rybczynski, J.; Wang, D.Z.; Kempa, K.; Ren, Z.F.

    2005-04-11

    Self-assembly of polystyrene microspheres has been utilized in a two-step masking technique to prepare triangular lattices of catalytic nanodots at low cost. Subsequent triangular lattices of aligned carbon nanotubes on a silicon substrate are achieved by plasma-enhanced chemical vapor deposition. Nickel is used both in the nanodots and in the secondary mask. The triangular lattices of carbon nanotube arrays as two-dimensional photonic crystals show higher geometrical symmetry than the hexagonal lattices previously reported, enabling broader applications including negative index of refraction and subwavelength lensing effect.

  12. Materials design for new superconductors.

    PubMed

    Norman, M R

    2016-07-01

    Since the announcement in 2011 of the Materials Genome Initiative by the Obama administration, much attention has been given to the subject of materials design to accelerate the discovery of new materials that could have technological implications. Although having its biggest impact for more applied materials like batteries, there is increasing interest in applying these ideas to predict new superconductors. This is obviously a challenge, given that superconductivity is a many body phenomenon, with whole classes of known superconductors lacking a quantitative theory. Given this caveat, various efforts to formulate materials design principles for superconductors are reviewed here, with a focus on surveying the periodic table in an attempt to identify cuprate analogues. PMID:27214291

  13. Composite materials: Testing and design

    NASA Technical Reports Server (NTRS)

    Whitcomb, John D. (Editor)

    1988-01-01

    The present conference discusses topics in the analysis of composite structures, composite materials' impact and compression behavior, composite materials characterization methods, composite failure mechanisms, NDE methods for composites, and filament-wound and woven composite materials' fabrication. Attention is given to the automated design of a composite plate for damage tolerance, the effects of adhesive layers on composite laminate impact damage, instability-related delamination growth in thermoset and thermoplastic composites, a simple shear fatigue test for unidirectional E-glass epoxy, the growth of elliptic delaminations in laminates under cyclic transverse shear, and the mechanical behavior of braided composite materials.

  14. Advanced Aerospace Materials by Design

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Djomehri, Jahed; Wei, Chen-Yu

    2004-01-01

    The advances in the emerging field of nanophase thermal and structural composite materials; materials with embedded sensors and actuators for morphing structures; light-weight composite materials for energy and power storage; and large surface area materials for in-situ resource generation and waste recycling, are expected to :revolutionize the capabilities of virtually every system comprising of future robotic and :human moon and mars exploration missions. A high-performance multiscale simulation platform, including the computational capabilities and resources of Columbia - the new supercomputer, is being developed to discover, validate, and prototype next generation (of such advanced materials. This exhibit will describe the porting and scaling of multiscale 'physics based core computer simulation codes for discovering and designing carbon nanotube-polymer composite materials for light-weight load bearing structural and 'thermal protection applications.

  15. The role of absorption and dispersion in resonant tunnelling through a negative index medium

    NASA Astrophysics Data System (ADS)

    Golla, D.; Deb, S.; Dutta Gupta, S.

    2011-01-01

    We study resonant tunneling through a layered medium with a passive negative index medium (NIM) slab as a constituent layer. Using a causal model for susceptibilities with the parameters of a recently reported metamaterial [G. Dolling, C. Enkrich, M. Wegener, C.M. Soukoulis, S. Linden, Opt. Lett. 31, 1800 (2006)] we show that resonant tunnelling and the associated delay are mostly suppressed. This is in sharp contrast with the naive approach of retaining phase velocity dispersion with arbitrary low losses, predicting sharp resonances with large associated delays. This is shown to be a nontrivial issue because of the necessity of losses for NIM behaviour, while their presence spoils the quality factor of the resonant devices.

  16. Materials design - An undergraduate course

    NASA Technical Reports Server (NTRS)

    Olson, G. B.

    1991-01-01

    General principles of systems engineering are applied to the design of materials to meet specific performance objectives. Results of ongoing reseach on processing/structure and structure/property relations in ultrahigh-strength steels are used to illustrate the formulation of quantitative microstructural objectives to achieve required property combinations, and the computer thermodynamics-based design of compositions responding to prescribed processing conditions. A class project addresses the conceptual design of a 7-component stainless bearing steel for a critical Space Shuttle application.

  17. Designed materials: what and how

    NASA Astrophysics Data System (ADS)

    Mazumder, Jyotirmoy; Dutta, Debasish; Ghosh, Amit K.; Kikuchi, Noboru

    2003-03-01

    Quest for a material to suit the service performance is almost as old as human civilization. So far materials engineers have developed a series of alloys, polymers, ceramics, and composites to serve many of the performance requirements in a modern society. However, challenges appear when one needs to satisfy more than one boundary condition. For example, a component with negative Coefficient of Thermal Expansion (CTE) using a ductile metal was almost impossible until recently. Synthesis of various technologies such as Direct Metal Deposition (DMD) Homogenization Design Method (HDM) and mutli material Computer Aided Design (CAD) was necessary to achieve this goal. Rapid fabrication of three-dimensional shapes of engineering materials such as H13 tool steel and nickel super alloys are now possible using Direct Materials Deposition (DMD) technique as well as similar techniques such as Light Engineered New Shaping (LENS) or Directed Light Fabrication (DLF). However, DMD has closed loop capability that enables better dimension and thermal cycle control. This enables one to deposit different material at different pixels with a given height directly from a CAD drawing. The feedback loop also controls the thermal cycle. H13 tool steel is one of the difficult alloys for deposition due to residual stress accumulation from martensitic transformation. However, it is the material of choice for the die and tool industry. DMD has demonstrated successful fabrication of complicated shapes and dies and tools, even with H13 alloys. This process also offers copper chill blocks and water-cooling channels as the integral part of the tool. On the other hand ZrO2 was co-deposited with nickel super alloys using DMD. Flexibility of the process is enormous and essentially it is an enabling technology to marterialize many a design. Using DMD in conjunction with HDM and multi-material CAD, one can produce components with predetermined performance such as negative co-efficient of expansion, by

  18. Surface polaritons in a negative-index metamaterial with active Raman gain

    NASA Astrophysics Data System (ADS)

    Tan, Chaohua; Huang, Guoxiang

    2015-02-01

    We propose a scheme to realize stable propagation of linear and nonlinear surface polaritons (SPs) by placing a N -type four-level quantum emitters at the interface between a dielectric and a negative-index metamaterial (NIMM). We show that in linear propagation regime SPs can acquire an active Raman gain (ARG) from a pump field and a gain doublet appears in the gain spectrum of a signal field induced by the quantum interference effect from a control field. The ARG can be used not only to completely compensate the Ohmic loss in the NIMM but also to acquire a superluminal group velocity for the SPs. We also show that in the nonlinear propagation regime a huge enhancement of the Kerr nonlinearity of the SPs can be obtained. As a result, ARG-assisted (1 + 1 )- and (2 + 1 )- dimensional superluminal surface polaritonic solitons with extremely low generation power may be produced based on the strong confinement of the electric field at the dielectric-NIMM interface.

  19. Spatial mapping of the internal and external electromagnetic fields of negative index metamaterials.

    PubMed

    Justice, Bryan J; Mock, Jack J; Guo, Liheng; Degiron, Aloyse; Schurig, David; Smith, David R

    2006-09-18

    We perform an experimental study of the phase and amplitude of microwaves interacting with and scattered by two-dimensional negative index metamaterials. The measurements are performed in a parallel plate waveguide apparatus at X-band frequencies (8-12 GHz), thus constraining the electromagnetic fields to two dimensions. A detection antenna is fixed to one of the plates, while a second plate with a fixed source antenna or waveguide is translated relative to the first plate. The detection antenna is inserted into, but not protruding below, the stationary plate so that fields internal to the metamaterial samples can be mapped. From the measured mappings of the electric field, the interplay between the microstructure of the metamaterial lattice and the macroscopic averaged response is revealed. For example, the mapped phase fronts within a metamaterial having a negative refractive index are consistent with a macroscopic phase-in accordance with the effective medium predictions-which travels in a direction opposite to the direction of propagation. The field maps are in excellent agreement with finite element numerical simulations performed assuming homogeneous metamaterial structures. PMID:19529250

  20. Shear-mediated contributions to the effective properties of soft acoustic metamaterials including negative index

    PubMed Central

    Forrester, Derek Michael; Pinfield, Valerie J.

    2015-01-01

    Here we show that, for sub-wavelength particles in a fluid, viscous losses due to shear waves and their influence on neighbouring particles significantly modify the effective acoustic properties, and thereby the conditions at which negative acoustic refraction occurs. Building upon earlier single particle scattering work, we adopt a multiple scattering approach to derive the effective properties (density, bulk modulus, wavenumber). We show,through theoretical prediction, the implications for the design of “soft” (ultrasonic) metamaterials based on locally-resonant sub-wavelength porous rubber particles, through selection of particle size and concentration, and demonstrate tunability of the negative speed zones by modifying the viscosity of the suspending medium. For these lossy materials with complex effective properties, we confirm the use of phase angles to define the backward propagation condition in preference to “single-” and “double-negative” designations. PMID:26686414

  1. Designer Nanocrystal Materials for Photovoltaics

    NASA Astrophysics Data System (ADS)

    Kagan, Cherie

    Advances in synthetic methods allow a wide range of semiconductor nanocrystals (NCs) to be tailored in size and shape and to be used as building blocks in the design of NC solids. However, the long, insulating ligands commonly employed in the synthesis of colloidal NCs inhibit strong interparticle coupling and charge transport once NCs are assembled into the solids state as NC arrays. We will describe the range of short, compact ligand chemistries we employ to exchange the long, insulating ligands used in synthesis and to increase interparticle coupling. These ligand exchange processes can have a dramatic influence on NC surface chemistry as well as NC organization in the solids, showing examples of short-range order. Synergistically, we use 1) thermal evaporation and diffusion and 2) wet-chemical methods to introduce extrinsic impurities and non-stoichiometry to passivate surface traps and dope NC solids. NC coupling and doping provide control over the density of states and the carrier type, concentration, mobility, and lifetime, which we characterize by a range of electronic and spectroscopic techniques. We will describe the importance of engineering device interfaces to design NC materials for solar photovoltaics.

  2. Development of Negative Index of Refraction Metamaterials with Split Ring Resonators and Wires for RF Lens Applications

    NASA Astrophysics Data System (ADS)

    Parazzoli, Claudio G.; Greegor, Robert B.; Tanielian, M. H.

    Metamaterials are engineered ring and wire composites whose response to an incident electromagnetic wave can be described by an effective negative dielectric permittivity ɛ and magnetic permeability μ. Simultaneous negative ɛ and μ within a given frequency band of a metamaterial gives rise to a negative index of refraction n. This has been demonstrated via a Snell's law experiment. The electromagnetic properties of many metamaterial structures in the microwave region are investigated through numerical simulations and experiments. A negative index of refraction, n, allows lenses with reduced primary (Seidel) aberrations compared to equivalent positive index lens. This is demonstrated both for cylindrical lenses and spherical lenses, as well as for the gradient index lenses. Detailed field maps of the focal region of the metamaterials lenses are made and compared to a comparable positive index of refraction lens.

  3. Materials informatics: a journey towards material design and synthesis.

    PubMed

    Takahashi, Keisuke; Tanaka, Yuzuru

    2016-06-28

    Materials informatics has been gaining popularity with the rapid development of computational materials science. However, collaborations between information science and materials science have not yet reached the success. There are several issues which need to be overcome in order to establish the field of materials informatics. Construction of material big data, implementation of machine learning, and platform design for materials discovery are discussed with potential solutions. PMID:27292550

  4. ALTERNATE MATERIALS IN DESIGN OF RADIOACTIVE MATERIAL PACKAGES

    SciTech Connect

    Blanton, P.; Eberl, K.

    2010-07-09

    This paper presents a summary of design and testing of material and composites for use in radioactive material packages. These materials provide thermal protection and provide structural integrity and energy absorption to the package during normal and hypothetical accident condition events as required by Title 10 Part 71 of the Code of Federal Regulations. Testing of packages comprising these materials is summarized.

  5. Some Thoughts on DIY Materials Design.

    ERIC Educational Resources Information Center

    Block, David

    1991-01-01

    Discusses the reasons that are often given against teacher-generated English-as-a-Foreign-Language materials and presents arguments in favor of DIY (Do It Yourself) materials design. (23 references) (GLR)

  6. OLED microdisplay design and materials

    NASA Astrophysics Data System (ADS)

    Wacyk, Ihor; Prache, Olivier; Ali, Tariq; Khayrullin, Ilyas; Ghosh, Amalkumar

    2010-04-01

    AMOLED microdisplays from eMagin Corporation are finding growing acceptance within the military display market as a result of their excellent power efficiency, wide operating temperature range, small size and weight, good system flexibility, and ease of use. The latest designs have also demonstrated improved optical performance including better uniformity, contrast, MTF, and color gamut. eMagin's largest format display is currently the SXGA design, which includes features such as a 30-bit wide RGB digital interface, automatic luminance regulation from -45 to +70°C, variable gamma control, and a dynamic range exceeding 50:000 to 1. This paper will highlight the benefits of eMagin's latest microdisplay designs and review the roadmap for next generation devices. The ongoing development of reduced size pixels and larger format displays (up to WUXGA) as well as new OLED device architecture (e.g. high-brightness yellow) will be discussed. Approaches being explored for improved performance in next generation designs such as lowpower serial interfaces, high frame rate operation, and new operational modes for reduction of motion artifacts will also be described. These developments should continue to enhance the appeal of AMOLED microdisplays for a broad spectrum of near-to-the-eye applications such as night vision, simulation and training, situational awareness, augmented reality, medical imaging, and mobile video entertainment and gaming.

  7. Managing Training Materials with Structured Text Design.

    ERIC Educational Resources Information Center

    Streit, Les D.; And Others

    1986-01-01

    Describes characteristics of structured text design; benefits of its use in training; benefits for developers of training materials and steps in preparing training materials. A case study illustrating how the structured text design process solved the sales training needs of the Mercedes-Benz Truck Company is presented. (MBR)

  8. Computational design and optimization of energy materials

    NASA Astrophysics Data System (ADS)

    Chan, Maria

    The use of density functional theory (DFT) to understand and improve energy materials for diverse applications - including energy storage, thermal management, catalysis, and photovoltaics - is widespread. The further step of using high throughput DFT calculations to design materials and has led to an acceleration in materials discovery and development. Due to various limitations in DFT, including accuracy and computational cost, however, it is important to leverage effective models and, in some cases, experimental information to aid the design process. In this talk, I will discuss efforts in design and optimization of energy materials using a combination of effective models, DFT, machine learning, and experimental information.

  9. Topology Optimization for Architected Materials Design

    NASA Astrophysics Data System (ADS)

    Osanov, Mikhail; Guest, James K.

    2016-07-01

    Advanced manufacturing processes provide a tremendous opportunity to fabricate materials with precisely defined architectures. To fully leverage these capabilities, however, materials architectures must be optimally designed according to the target application, base material used, and specifics of the fabrication process. Computational topology optimization offers a systematic, mathematically driven framework for navigating this new design challenge. The design problem is posed and solved formally as an optimization problem with unit cell and upscaling mechanics embedded within this formulation. This article briefly reviews the key requirements to apply topology optimization to materials architecture design and discusses several fundamental findings related to optimization of elastic, thermal, and fluidic properties in periodic materials. Emerging areas related to topology optimization for manufacturability and manufacturing variations, nonlinear mechanics, and multiscale design are also discussed.

  10. Role of phase matching in pulsed second-harmonic generation: Walk-off and phase-locked twin pulses in negative-index media

    SciTech Connect

    Roppo, Vito; Centini, Marco; Sibilia, Concita; Bertolotti, Mario; De Ceglia, Domenico; Scalora, Michael; Akozbek, Neset; Bloemer, Mark J.; Haus, Joseph W.; Kosareva, Olga G.; Kandidov, Valery P.

    2007-09-15

    The present investigation is concerned with the study of pulsed second-harmonic generation under conditions of phase and group velocity mismatch, and generally low conversion efficiencies and pump intensities. In positive-index, nonmetallic materials, we generally find qualitative agreement with previous reports regarding the presence of a double-peaked second harmonic signal, which comprises a pulse that walks off and propagates at the nominal group velocity one expects at the second-harmonic frequency, and a second pulse that is 'captured' and propagates under the pump pulse. We find that the origin of the double-peaked structure resides in a phase-locking mechanism that characterizes not only second-harmonic generation, but also {chi}{sup (3)} processes and third-harmonic generation. The phase-locking mechanism that we describe occurs for arbitrarily small pump intensities, and so it is not a soliton effect, which usually relies on a threshold mechanism, although multicolor solitons display similar phase locking characteristics. Thus, in second harmonic generation a phase-matched component is always generated, even under conditions of material phase mismatch: This component is anomalous, because the material does not allow energy exchange between the pump and the second-harmonic beam. On the other hand, if the material is phase matched, phase locking and phase matching are indistinguishable, and the conversion process becomes efficient. We also report a similar phase-locking phenomenon in negative index materials. A spectral analysis of the pump and the generated signals reveals that the phase-locking phenomenon causes the forward moving, phase-locked second-harmonic pulse to experience the same negative index as the pump pulse, even though the index of refraction at the second-harmonic frequency is positive. Our analysis further shows that the reflected second-harmonic pulse generated at the interface and the forward-moving, phase-locked pulse appear to be part

  11. Design and Manufacture of Energy Absorbing Materials

    SciTech Connect

    Duoss, Eric

    2014-05-28

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  12. Design and Manufacture of Energy Absorbing Materials

    ScienceCinema

    Duoss, Eric

    2014-05-30

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  13. Computationally Designed Molecularly Imprinted Materials

    NASA Astrophysics Data System (ADS)

    Pavel, Dumitru; Lagowski, Jolanta; Faid, Karim

    2004-03-01

    Molecular dynamics simulations were carried out for different molecular systems in order to predict the binding affinities, binding energies, binding distances and the active site groups between the simulated molecular systems and different bio-ligands (theophylline and its derivatives), which have been designed and minimized using molecular simulation techniques. The first simulated molecular systems consisted of a ligand and functional monomer, such as methacrylic acid and its derivatives. For each pair of molecular systems, (10 monomers with a ligand and 10 monomers without a ligand) a total energy difference was calculated in order to estimate the binding energy between a ligand and the corresponding monomers. The analysis of the simulated functional monomers with ligands indicates that the functional group of monomers interacting with ligands tends to be either COOH or CH2=CH. The distances between the ligand and monomer, in the most stable cases as indicated above, are between 2.0-4.5 Å. The second simulated molecular systems consisted of a ligand and a polymer. The polymers were obtained from monomers that were simulated above. And similar to monomer study, for each pair of molecular systems, (polymer with a ligand and polymer without a ligand) a total energy difference was calculated in order to estimate the binding energy between ligand and the corresponding polymer. The binding distance between the active site of a polymer and a ligand will also be discussed.

  14. Plasmon Injection to Compensate and Control Losses in Negative Index Metamaterials.

    PubMed

    Sadatgol, Mehdi; Özdemir, Şahin K; Yang, Lan; Güney, Durdu Ö

    2015-07-17

    Metamaterials have introduced a whole new world of unusual materials with functionalities that cannot be attained in naturally occurring material systems by mimicking and controlling the natural phenomena at subwavelength scales. However, the inherent absorption losses pose a fundamental challenge to the most fascinating applications of metamaterials. Based on a novel plasmon injection (PI or Π) scheme, we propose a coherent optical amplification technique to compensate losses in metamaterials. Although the proof of concept device here operates under normal incidence only, our proposed scheme can be generalized to an arbitrary form of incident waves. The Π scheme is fundamentally different from major optical amplification schemes. It does not require a gain medium, interaction with phonons, or any nonlinear medium. The Π scheme allows for loss-free metamaterials. It is ideally suited for mitigating losses in metamaterials operating in the visible spectrum and is scalable to other optical frequencies. These findings open the possibility of reviving the early dreams of making "magical" metamaterials from scratch. PMID:26230802

  15. Plasmon Injection to Compensate and Control Losses in Negative Index Metamaterials

    NASA Astrophysics Data System (ADS)

    Sadatgol, Mehdi; Ã-zdemir, Şahin K.; Yang, Lan; Güney, Durdu Ã.-.

    2015-07-01

    Metamaterials have introduced a whole new world of unusual materials with functionalities that cannot be attained in naturally occurring material systems by mimicking and controlling the natural phenomena at subwavelength scales. However, the inherent absorption losses pose a fundamental challenge to the most fascinating applications of metamaterials. Based on a novel plasmon injection (PI or Π ) scheme, we propose a coherent optical amplification technique to compensate losses in metamaterials. Although the proof of concept device here operates under normal incidence only, our proposed scheme can be generalized to an arbitrary form of incident waves. The Π scheme is fundamentally different from major optical amplification schemes. It does not require a gain medium, interaction with phonons, or any nonlinear medium. The Π scheme allows for loss-free metamaterials. It is ideally suited for mitigating losses in metamaterials operating in the visible spectrum and is scalable to other optical frequencies. These findings open the possibility of reviving the early dreams of making "magical" metamaterials from scratch.

  16. Reestablishing Design in the Materials Curriculum

    ERIC Educational Resources Information Center

    Larsen, William L.

    1975-01-01

    Outlines one approach to the teaching of materials engineering design within the context of metallurgical engineering. This approach uses a problem solving situation and criteria for an appropriate problem are presented. (GS)

  17. Design principles for therapeutic angiogenic materials

    NASA Astrophysics Data System (ADS)

    Briquez, Priscilla S.; Clegg, Lindsay E.; Martino, Mikaël M.; Gabhann, Feilim Mac; Hubbell, Jeffrey A.

    2016-01-01

    Despite extensive research, pro-angiogenic drugs have failed to translate clinically, and therapeutic angiogenesis, which has potential in the treatment of various cardiovascular diseases, remains a major challenge. Physiologically, angiogenesis — the process of blood-vessel growth from existing vasculature — is regulated by a complex interplay of biophysical and biochemical cues from the extracellular matrix (ECM), angiogenic factors and multiple cell types. The ECM can be regarded as the natural 3D material that regulates angiogenesis. Here, we leverage knowledge of ECM properties to derive design rules for engineering pro-angiogenic materials. We propose that pro-angiogenic materials should be biomimetic, incorporate angiogenic factors and mimic cooperative interactions between growth factors and the ECM. We highlight examples of material designs that demonstrate these principles and considerations for designing better angiogenic materials.

  18. Design of materials with prescribed nonlinear properties

    NASA Astrophysics Data System (ADS)

    Wang, F.; Sigmund, O.; Jensen, J. S.

    2014-09-01

    We systematically design materials using topology optimization to achieve prescribed nonlinear properties under finite deformation. Instead of a formal homogenization procedure, a numerical experiment is proposed to evaluate the material performance in longitudinal and transverse tensile tests under finite deformation, i.e. stress-strain relations and Poissons ratio. By minimizing errors between actual and prescribed properties, materials are tailored to achieve the target. Both two dimensional (2D) truss-based and continuum materials are designed with various prescribed nonlinear properties. The numerical examples illustrate optimized materials with rubber-like behavior and also optimized materials with extreme strain-independent Poissons ratio for axial strain intervals of εi∈[0.00, 0.30].

  19. Material design using surrogate optimization algorithm

    NASA Astrophysics Data System (ADS)

    Khadke, Kunal R.

    Nanocomposite ceramics have been widely studied in order to tailor desired properties at high temperatures. Methodologies for development of material design are still under effect . While finite element modeling (FEM) provides significant insight on material behavior, few design researchers have addressed the design paradox that accompanies this rapid design space expansion. A surrogate optimization model management framework has been proposed to make this design process tractable. In the surrogate optimization material design tool, the analysis cost is reduced by performing simulations on the surrogate model instead of high density finite element model. The methodology is incorporated to find the optimal number of silicon carbide (SiC) particles, in a silicon-nitride Si3N 4 composite with maximum fracture energy [2]. Along with a deterministic optimization algorithm, model uncertainties have also been considered with the use of robust design optimization (RDO) method ensuring a design of minimum sensitivity to changes in the parameters. These methodologies applied to nanocomposites design have a signicant impact on cost and design cycle time reduced.

  20. Designing Jammed Materials from the Particle Up

    NASA Astrophysics Data System (ADS)

    Miskin, Marc

    2015-03-01

    Identifying which microscopic features produce a desired macroscopic behavior is a problem at the forefront of materials science. This task is materials design, and within it, new challenges have emerged from tailoring packings of particles jammed into a rigid state. For these materials, particle shape is a key parameter by which the response of a packing can be tuned. Yet designing via shape faces two unique complications: first there is no general theory that calculates the response of an aggregate given a particle shape, and second, there is no straightforward way to explore the space of all particle geometries. This talk summarizes recent results that address these challenges to design jammed materials from the particle up. It shows how simulations, experiments, and state-of-the-art optimization engines come together to form a complete system that identifies extreme materials. As examples, it will show how this system can create particle shapes that form the stiffest, softest, densest, loosest, most dissipative and strain-stiffening aggregates. Finally, it will discuss the how these results relate to the general task of materials design and the exciting possibilities associated with optimizing, tuning and rationally constructing new breeds of jammed materials.

  1. Thermophotovoltaic emitter material selection and design

    SciTech Connect

    Saxton, P.C.; Moran, A.L.; Harper, M.J.; Lindler, K.W.

    1997-07-01

    Thermophotovoltaics (TPV) is a potentially attractive direct energy conversion technology. It reduces the need for complex machinery with moving parts and maintenance. TPV generators can be run from a variety of heat sources including waste heat for smaller scale operations. The US Naval Academy`s goal was to build a small experimental thermophotovoltaic generator powered by combustion gases from a General Electric T-58 helicopter gas turbine. The design of the generator imposes material limitations that directly affect emitter and structural materials selection. This paper details emitter material goals and requirements, and the methods used to select suitable candidate emitter materials for further testing.

  2. Computational design of fused heterocyclic energetic materials

    NASA Astrophysics Data System (ADS)

    Tsyshevskiy, Roman; Pagoria, Philip; Batyrev, Iskander; Kuklja, Maija

    A continuous traditional search for effective energetic materials is often based on a trial and error approach. Understanding of fundamental correlations between the structure and sensitivity of the materials remains the main challenge for design of novel energetics due to the complexity of the behavior of energetic materials. State of the art methods of computational chemistry and solid state physics open new compelling opportunities in simulating and predicting a response of the energetic material to various external stimuli. Hence, theoretical and computational studies can be effectively used not only for an interpretation of sensitivity mechanisms of widely used explosives, but also for identifying criteria for material design prior to its synthesis and experimental characterization. We report here, how knowledge on thermal stability of recently synthesized materials of LLM series is used for design of novel fused heterocyclic energetic materials, including DNBTT (2,7-dinitro-4H,9H-bis([1, 2, 4"]triazolo)[1,5-b:1',5'-e][1, 2, 4, 5]tetrazine), compound with high thermal stability, which is on par or better than that of TATB. This research is supported by ONR (Grant N00014-12-1-0529), NSF XSEDE resources (Grant DMR-130077) and DOE NERSC resources (Contract DE-AC02-05CH11231).

  3. Materials design for electrocatalytic carbon capture

    NASA Astrophysics Data System (ADS)

    Tan, Xin; Tahini, Hassan A.; Smith, Sean C.

    2016-05-01

    We discuss our philosophy for implementation of the Materials Genome Initiative through an integrated materials design strategy, exemplified here in the context of electrocatalytic capture and separation of CO2 gas. We identify for a group of 1:1 X-N graphene analogue materials that electro-responsive switchable CO2 binding behavior correlates with a change in the preferred binding site from N to the adjacent X atom as negative charge is introduced into the system. A reconsideration of conductive N-doped graphene yields the discovery that the N-dopant is able to induce electrocatalytic binding of multiple CO2 molecules at the adjacent carbon sites.

  4. Adaptive strategies for materials design using uncertainties

    DOE PAGESBeta

    Balachandran, Prasanna V.; Xue, Dezhen; Theiler, James; Hogden, John; Lookman, Turab

    2016-01-21

    Here, we compare several adaptive design strategies using a data set of 223 M2AX family of compounds for which the elastic properties [bulk (B), shear (G), and Young’s (E) modulus] have been computed using density functional theory. The design strategies are decomposed into an iterative loop with two main steps: machine learning is used to train a regressor that predicts elastic properties in terms of elementary orbital radii of the individual components of the materials; and a selector uses these predictions and their uncertainties to choose the next material to investigate. The ultimate goal is to obtain a material withmore » desired elastic properties in as few iterations as possible. We examine how the choice of data set size, regressor and selector impact the design. We find that selectors that use information about the prediction uncertainty outperform those that don’t. Our work is a step in illustrating how adaptive design tools can guide the search for new materials with desired properties.« less

  5. Adaptive Strategies for Materials Design using Uncertainties

    NASA Astrophysics Data System (ADS)

    Balachandran, Prasanna V.; Xue, Dezhen; Theiler, James; Hogden, John; Lookman, Turab

    2016-01-01

    We compare several adaptive design strategies using a data set of 223 M2AX family of compounds for which the elastic properties [bulk (B), shear (G), and Young’s (E) modulus] have been computed using density functional theory. The design strategies are decomposed into an iterative loop with two main steps: machine learning is used to train a regressor that predicts elastic properties in terms of elementary orbital radii of the individual components of the materials; and a selector uses these predictions and their uncertainties to choose the next material to investigate. The ultimate goal is to obtain a material with desired elastic properties in as few iterations as possible. We examine how the choice of data set size, regressor and selector impact the design. We find that selectors that use information about the prediction uncertainty outperform those that don’t. Our work is a step in illustrating how adaptive design tools can guide the search for new materials with desired properties.

  6. Adaptive Strategies for Materials Design using Uncertainties

    PubMed Central

    Balachandran, Prasanna V.; Xue, Dezhen; Theiler, James; Hogden, John; Lookman, Turab

    2016-01-01

    We compare several adaptive design strategies using a data set of 223 M2AX family of compounds for which the elastic properties [bulk (B), shear (G), and Young’s (E) modulus] have been computed using density functional theory. The design strategies are decomposed into an iterative loop with two main steps: machine learning is used to train a regressor that predicts elastic properties in terms of elementary orbital radii of the individual components of the materials; and a selector uses these predictions and their uncertainties to choose the next material to investigate. The ultimate goal is to obtain a material with desired elastic properties in as few iterations as possible. We examine how the choice of data set size, regressor and selector impact the design. We find that selectors that use information about the prediction uncertainty outperform those that don’t. Our work is a step in illustrating how adaptive design tools can guide the search for new materials with desired properties. PMID:26792532

  7. A Bridge for Accelerating Materials by Design

    SciTech Connect

    Sumpter, Bobby G.; Vasudevan, Rama K.; Potok, Thomas E.; Kalinin, Sergei V.

    2015-11-25

    Recent technical advances in the area of nanoscale imaging, spectroscopy, and scattering/diffraction have led to unprecedented capabilities for investigating materials structural, dynamical and functional characteristics. In addition, recent advances in computational algorithms and computer capacities that are orders of magnitude larger/faster have enabled large-scale simulations of materials properties starting with nothing but the identity of the atomic species and the basic principles of quantum- and statistical-mechanics and thermodynamics. Along with these advances, an explosion of high-resolution data has emerged. This confluence of capabilities and rise of big data offer grand opportunities for advancing materials sciences but also introduce several challenges. In this editorial we identify challenges impeding progress towards advancing materials by design (e.g., the design/discovery of materials with improved properties/performance), possible solutions, and provide examples of scientific issues that can be addressed by using a tightly integrated approach where theory and experiments are linked through big-deep data.

  8. A Bridge for Accelerating Materials by Design

    DOE PAGESBeta

    Sumpter, Bobby G.; Vasudevan, Rama K.; Potok, Thomas E.; Kalinin, Sergei V.

    2015-11-25

    Recent technical advances in the area of nanoscale imaging, spectroscopy, and scattering/diffraction have led to unprecedented capabilities for investigating materials structural, dynamical and functional characteristics. In addition, recent advances in computational algorithms and computer capacities that are orders of magnitude larger/faster have enabled large-scale simulations of materials properties starting with nothing but the identity of the atomic species and the basic principles of quantum- and statistical-mechanics and thermodynamics. Along with these advances, an explosion of high-resolution data has emerged. This confluence of capabilities and rise of big data offer grand opportunities for advancing materials sciences but also introduce several challenges.more » In this editorial we identify challenges impeding progress towards advancing materials by design (e.g., the design/discovery of materials with improved properties/performance), possible solutions, and provide examples of scientific issues that can be addressed by using a tightly integrated approach where theory and experiments are linked through big-deep data.« less

  9. Ureteral Stents. New Materials and Designs

    NASA Astrophysics Data System (ADS)

    Monga, Manoj

    2008-09-01

    Issues of stent migration and challenges of stent placement can be addressed adequately with current stent designs and materials, and an emphasis on precision in technique. Future changes in ureteral stents will need to maintain the current standard that has been set with existing devices in these regards. In contrast, new advances are sorely needed in encrustation and infection associated with ureteral stents. The main target for future development in ureteral stent materials lies in a biodegradable stent that degrades either on demand or degrades reliably within one-month with predictable degradation patterns that do not predispose to urinary obstruction, discomfort or need for secondary procedures. The main target for future development in ureteral stent design is improved patient comfort.

  10. Progress in material design for biomedical applications

    PubMed Central

    Tibbitt, Mark W.; Rodell, Christopher B.; Burdick, Jason A.; Anseth, Kristi S.

    2015-01-01

    Biomaterials that interface with biological systems are used to deliver drugs safely and efficiently; to prevent, detect, and treat disease; to assist the body as it heals; and to engineer functional tissues outside of the body for organ replacement. The field has evolved beyond selecting materials that were originally designed for other applications with a primary focus on properties that enabled restoration of function and mitigation of acute pathology. Biomaterials are now designed rationally with controlled structure and dynamic functionality to integrate with biological complexity and perform tailored, high-level functions in the body. The transition has been from permissive to promoting biomaterials that are no longer bioinert but bioactive. This perspective surveys recent developments in the field of polymeric and soft biomaterials with a specific emphasis on advances in nano- to macroscale control, static to dynamic functionality, and biocomplex materials. PMID:26598696

  11. Material constraints on high-speed design

    NASA Astrophysics Data System (ADS)

    Bucur, Diana; Militaru, Nicolae

    2015-02-01

    Current high-speed circuit designs with signal rates up to 100Gbps and above are implying constraints for dielectric and conductive materials and their dependence of frequency, for component elements and for production processes. The purpose of this paper is to highlight through various simulation results the frequency dependence of specific parameters like insertion and return loss, eye diagrams, group delay that are part of signal integrity analyses type. In low-power environment designs become more complex as the operation frequency increases. The need for new materials with spatial uniformity for dielectric constant is a need for higher data rates circuits. The fiber weave effect (FWE) will be analyzed through the eye diagram results for various dielectric materials in a differential signaling scheme given the fact that the FWE is a phenomenon that affects randomly the performance of the circuit on balanced/differential transmission lines which are typically characterized through the above mentioned approaches. Crosstalk between traces is also of concern due to propagated signals that have tight rise and fall times or due to high density of the boards. Criteria should be considered to achieve maximum performance of the designed system requiring critical electronic properties.

  12. Computational Materials Program for Alloy Design

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo

    2005-01-01

    The research program sponsored by this grant, "Computational Materials Program for Alloy Design", covers a period of time of enormous change in the emerging field of computational materials science. The computational materials program started with the development of the BFS method for alloys, a quantum approximate method for atomistic analysis of alloys specifically tailored to effectively deal with the current challenges in the area of atomistic modeling and to support modern experimental programs. During the grant period, the program benefited from steady growth which, as detailed below, far exceeds its original set of goals and objectives. Not surprisingly, by the end of this grant, the methodology and the computational materials program became an established force in the materials communitiy, with substantial impact in several areas. Major achievements during the duration of the grant include the completion of a Level 1 Milestone for the HITEMP program at NASA Glenn, consisting of the planning, development and organization of an international conference held at the Ohio Aerospace Institute in August of 2002, finalizing a period of rapid insertion of the methodology in the research community worlwide. The conference, attended by citizens of 17 countries representing various fields of the research community, resulted in a special issue of the leading journal in the area of applied surface science. Another element of the Level 1 Milestone was the presentation of the first version of the Alloy Design Workbench software package, currently known as "adwTools". This software package constitutes the first PC-based piece of software for atomistic simulations for both solid alloys and surfaces in the market.Dissemination of results and insertion in the materials community worldwide was a primary focus during this period. As a result, the P.I. was responsible for presenting 37 contributed talks, 19 invited talks, and publishing 71 articles in peer-reviewed journals, as

  13. Application of New Materials in the Household Appliances Design

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Ren, Y.

    The widespread use of new materials in household appliances industry, not only help those products to get rid of the appearance shackles caused by original materials, but also gave the designers the freedom to open up the world of product design. This paper aims to analyze the impact of new materials for home appliances design through relevant research, to explore the application of new material in household appliances functional design, shape design, color design and emotional design, etc., so as to reveal the impact and promoting effects of new material in household appliances world, as well as the prospects of new material in future household appliances design.

  14. Computational design of microvascular biomimetic materials

    NASA Astrophysics Data System (ADS)

    Aragon, Alejandro Marcos

    Biomimetic microvascular materials are increasingly considered for a variety of autonomic healing, cooling and sensing applications. The microvascular material of interest in this work consists of a network of hollow microchannels, with diameters as small as 10 mum, embedded in a polymeric matrix. Recent advances in the manufacturing of this new class of materials have allowed for the creation of very complex 2D and 3D structures. The computational design of such network structures, which is the focus of this work, involves a set of particular challenges, including a large number of design variables (e.g., topology of the network, number of diameters to consider and their sizes) that define the network, and a large number of multidisciplinary objective functions and constraints that drive the optimization process. The computational design tool to be developed must be capable of capturing the trade-off between the different objective and constraint functions, as, for example, networks designed for flow efficiency are likely to have a topology that is very different from those designed for structural integrity or thermal control. In this work, we propose to design these materials using Genetic Algorithms (GAs), the most common methodology within a broader category of Evolutionary Algorithms (EAs). GAs can be combined with a Pareto-selection mechanism to create Multi-Objective Genetic Algorithms (MOGAs), which enable the optimization of an arbitrary number of objective functions. As a result, a Pareto-optimal front is obtained, where all candidates are optimal solutions to the optimization problem. Adding a procedure to deal with constraints results in a powerful tool for multi-objective constrained optimization. The method allows the use of discrete variable problems and it does not require any a priori knowledge of the optimal solution. Furthermore, GAs search the entire decision space so the optimal solutions found are likely to be global. The

  15. Materials by Design: Merging Proteins and Music

    PubMed Central

    Wong, Joyce Y.; McDonald, John; Taylor-Pinney, Micki; Spivak, David I.; Kaplan, David L.; Buehler, Markus J.

    2013-01-01

    Tailored materials with tunable properties are crucial for applications as biomaterials, for drug delivery, as functional coatings, or as lightweight composites. An emerging paradigm in designing such materials is the construction of hierarchical assemblies of simple building blocks into complex architectures with superior properties. We review this approach in a case study of silk, a genetically programmable and processable biomaterial, which, in its natural role serves as a versatile protein fiber with hierarchical organization to provide structural support, prey procurement or protection of eggs. Through an abstraction of knowledge from the physical system, silk, to a mathematical model using category theory, we describe how the mechanism of spinning fibers from proteins can be translated into music through a process that assigns a set of rules that governs the construction of the system. This technique allows one to express the structure, mechanisms and properties of the ‘material’ in a very different domain, ‘music’. The integration of science and art through categorization of structure-property relationships presents a novel paradigm to create new bioinspired materials, through the translation of structures and mechanisms from distinct hierarchical systems and in the context of the limited number of building blocks that universally governs these systems. PMID:23997808

  16. Design education in metallurgical and materials engineering

    NASA Astrophysics Data System (ADS)

    Schlesinger, Mark E.; Mikkola, Donald E.

    1993-12-01

    In general, the attendance level and interest in the discussions that took place following the presentations at each of the four sessions of the symposium suggest that educational programming at future TMS meetings has a very solid constituency. The organization of the symposium Powder Processing Education for the Year 2000 by the Materials Design & Manufacturing Division's Powder Metallurgy Committee for the 1994 TMS Annual Meeting is likely to provide further demonstration of this level of interest. As our profession continues to evolve, TMS has the opportunity to play a signal role as a conduit of information among professionals and educators wishing to improve their "product" and between educators wishing to share with others the best means of obtaining such improvement.

  17. Tools for Material Design and Selection

    NASA Astrophysics Data System (ADS)

    Wehage, Kristopher

    The present thesis focuses on applications of numerical methods to create tools for material characterization, design and selection. The tools generated in this work incorporate a variety of programming concepts, from digital image analysis, geometry, optimization, and parallel programming to data-mining, databases and web design. The first portion of the thesis focuses on methods for characterizing clustering in bimodal 5083 Aluminum alloys created by cryomilling and powder metallurgy. The bimodal samples analyzed in the present work contain a mixture of a coarse grain phase, with a grain size on the order of several microns, and an ultra-fine grain phase, with a grain size on the order of 200 nm. The mixing of the two phases is not homogeneous and clustering is observed. To investigate clustering in these bimodal materials, various microstructures were created experimentally by conventional cryomilling, Hot Isostatic Pressing (HIP), Extrusion, Dual-Mode Dynamic Forging (DMDF) and a new 'Gradient' cryomilling process. Two techniques for quantitative clustering analysis are presented, formulated and implemented. The first technique, the Area Disorder function, provides a metric of the quality of coarse grain dispersion in an ultra-fine grain matrix and the second technique, the Two-Point Correlation function, provides a metric of long and short range spatial arrangements of the two phases, as well as an indication of the mean feature size in any direction. The two techniques are implemented on digital images created by Scanning Electron Microscopy (SEM) and Electron Backscatter Detection (EBSD) of the microstructures. To investigate structure--property relationships through modeling and simulation, strategies for generating synthetic microstructures are discussed and a computer program that generates randomized microstructures with desired configurations of clustering described by the Area Disorder Function is formulated and presented. In the computer program, two

  18. Learning from systems biology: An ``Omics'' approach to materials design

    NASA Astrophysics Data System (ADS)

    Rajan, Krishna

    2008-03-01

    An understanding of systems biology provides an excellent paradigm for the materials scientist. Ultimately one would like to take an “atoms-applications” approach to materials design. This paper describes how the concepts of genomics, proteomics, and other biological behavior which form the foundations of modern biology can be applied to materials design through materials informatics.

  19. Materials Design for Block Copolymer Lithography

    NASA Astrophysics Data System (ADS)

    Sweat, Daniel Patrick

    Block copolymers (BCPs) have attracted a great deal of scientific and technological interest due to their ability to spontaneously self-assemble into dense periodic nanostructures with a typical length scale of 5 to 50 nm. The use of self-assembled BCP thin-films as templates to form nanopatterns over large-area is referred to as BCP lithography. Directed self-assembly of BCPs is now viewed as a viable candidate for sub-20 nm lithography by the semiconductor industry. However, there are multiple aspects of assembly and materials design that need to be addressed in order for BCP lithography to be successful. These include substrate modification with polymer brushes or mats, tailoring of the block copolymer chemistry, understanding thin-film assembly and developing epitaxial like methods to control long range alignment. The rational design, synthesis and self-assembly of block copolymers with large interaction parameters (chi) is described in the first part of this dissertation. Two main blocks were chosen for introducing polarity into the BCP system, namely poly(4-hydroxystyrene) and poly(2-vinylpyridine). Each of these blocks are capable of ligating Lewis acids which can increase the etch contrast between the blocks allowing for facile pattern transfer to the underlying substrate. These BCPs were synthesized by living anionic polymerization and showed excellent control over molecular weight and dispersity, providing access to sub 5-nm domain sizes. Polymer brushes consist of a polymer chain with one end tethered to the surface and have wide applicability in tuning surface energy, forming responsive surfaces and increasing biocompatibility. In the second part of the dissertation, we present a universal method to grow dense polymer brushes on a wide range of substrates and combine this chemistry with BCP assembly to fabricate nanopatterned polymer brushes. This is the first demonstration of introducing additional functionality into a BCP directing layer and opens up

  20. Mass of materials: the impact of designers on construction ergonomics.

    PubMed

    Smallwood, John

    2012-01-01

    Many construction injuries are musculoskeletal related in the form of sprains and strains arising from the handling of materials, which are specified by designers. The paper presents the results of a study conducted among delegates attending two 'designing for H&S' (DfH&S) seminars using a questionnaire. The salient findings include: the level of knowledge relative to the mass and density of materials is limited; designers generally do not consider the mass and density of materials when designing structures and elements and specifying materials; to a degree designers appreciate that the mass and density of materials impact on construction ergonomics; designers rate their knowledge of the mass and density of materials as limited, and designers appreciate the potential of the consideration of the mass and density of materials to contribute to an improvement in construction ergonomics. Conclusions include: designers lack the requisite knowledge relative to the mass and density of materials; designers are thus precluded from conducting optimum design hazard identification and risk assessments, and tertiary built environment designer education does not enlighten designers relative to construction ergonomics. Recommendations include: tertiary built environment designer education should construction ergonomics; professional associations should raise the level of awareness relative to construction ergonomics, and design practices should include a category 'mass and density of materials' in their practice libraries. PMID:22317574

  1. Nanoscale material design for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Bao, Hua

    /nanowire array solar cells. Phonon-assisted electron decay in semiconductor quantum dots is also investigated in this work. In semiconductor solar cell, a large portion of energy loss is by the fast hot electron cooling, in which a high energy electron decays to the electronic band gap by creating a series of phonons. The excessive electrical energy is then converted to heat and wasted, so that the total photovoltaic energy conversion efficiency is limited. The electron decay rate reduces in semiconductor quantum dots, due to the discrete electron energy levels created by quantum confinement. To design quantum dots with the slowest decay rate, we use the non-adiabatic molecular dynamics to perform real-time simulations of the phonon-assisted electron decay process. This method is based on time-dependent density functional theory, and can directly predict the phonon-assisted electron decay time using the initial quantum dot structure as the only input. The numerical simulation shows that the phonon-induced electron decay can be slowed down in a small PbSe quantum dot. The temperature-dependent relaxation in this quantum dot is also studied, which helps us to propose a multi-channel relaxation mechanism. This mechanism provides new insights to the understanding of electron decay process in quantum dots. The results from this study have potentially important applications in solar energy harvesting and radiative thermal management. It offers a new perspective of nanoscale engineering of materials to achieve more efficient photovoltaic energy conversion.

  2. Material for Point Design (final summary of DIME material)

    SciTech Connect

    Bradley, Paul A.

    2014-02-25

    These slides summarize the motivation of the Defect Induced Mix Experiment (DIME) project, the “point design” of the Polar Direct Drive (PDD) version of the NIF separated reactant capsule, the experimental requirements, technical achievements, and some useful backup material. These slides are intended to provide much basic material in one convenient location and will hopefully be of some use for subsequent experimental projects.

  3. Acquisition of Instructional Material Information as a Function of Manual Design and Material Complexity.

    ERIC Educational Resources Information Center

    Altman, Reuben; And Others

    The study, with 52 preservice special education teachers, focused on effects of two types of teacher manual design and two levels of material complexity on comprehension of instructional materials utilization. Two materials were selected from an instructional materials collection for less complex material and for more complex material,…

  4. FOREWORD: Computational methodologies for designing materials Computational methodologies for designing materials

    NASA Astrophysics Data System (ADS)

    Rahman, Talat S.

    2009-02-01

    It would be fair to say that in the past few decades, theory and computer modeling have played a major role in elucidating the microscopic factors that dictate the properties of functional novel materials. Together with advances in experimental techniques, theoretical methods are becoming increasingly capable of predicting properties of materials at different length scales, thereby bringing in sight the long-sought goal of designing material properties according to need. Advances in computer technology and their availability at a reasonable cost around the world have made tit all the more urgent to disseminate what is now known about these modern computational techniques. In this special issue on computational methodologies for materials by design we have tried to solicit articles from authors whose works collectively represent the microcosm of developments in the area. This turned out to be a difficult task for a variety of reasons, not the least of which is space limitation in this special issue. Nevertheless, we gathered twenty articles that represent some of the important directions in which theory and modeling are proceeding in the general effort to capture the ability to produce materials by design. The majority of papers presented here focus on technique developments that are expected to uncover further the fundamental processes responsible for material properties, and for their growth modes and morphological evolutions. As for material properties, some of the articles here address the challenges that continue to emerge from attempts at accurate descriptions of magnetic properties, of electronically excited states, and of sparse matter, all of which demand new looks at density functional theory (DFT). I should hasten to add that much of the success in accurate computational modeling of materials emanates from the remarkable predictive power of DFT, without which we would not be able to place the subject on firm theoretical grounds. As we know and will also

  5. Design and analysis of novel photocatalytic materials

    NASA Astrophysics Data System (ADS)

    Boppana, Venkata Bharat Ram

    The development of sustainable sources of energy to decrease our dependence on non-renewable fossil fuels and the reduction of emissions causing global warming are important technological challenges of the 21st century. Production of solar fuels by photocatalysis is one potential route to reduce the impact of those problems. The most widely applied photocatalyst is TiO2 because it is stable, non-toxic and inexpensive. Still, it cannot utilize the solar spectrum efficiently as its band gap is 3.2 eV thus able to absorb only 3% of sun light. This thesis therefore explores multiple avenues towards improving the light absorption capability of semiconductor materials without loss in activity. To achieve this objective, the valence band hybridization method of band gap reduction was utilized. This technique is based on introducing new orbitals at the top of valence band of the semiconductor that can then hybridize with existing orbitals. The hybridization then raises the maximum of the valence band thereby reducing the band gap. This technique has the added advantage of increasing the mobility of oxidizing holes in the now dispersed valence band. In practice, this can be achieved by introducing N 2p or Sn 5s orbitals in the valence band of an oxide. We initially designed novel zinc gallium oxy-nitrides, with the spinel structure and band gaps in the visible region of the solar spectrum, by nitridation of a zinc gallate precursor produced by sol-gel synthesis. These spinel oxy-nitrides have band gaps of 2.5 to 2.7 eV, surface areas of 16 to 36 m 2/g, and nitrogen content less than 1.5%. They are active towards degradation of organic molecules in visible light. Density functional theory calculations show that this band gap reduction in part is associated with hybridization between the dopant N 2p states with Zn 3d orbitals at the top of the valence band. While spinel oxy-nitrides are produced under nitridation at 550°C, at higher temperatures they are consumed to form

  6. 15 CFR 922.22 - Development of designation materials.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Development of designation materials... Sanctuaries § 922.22 Development of designation materials. (a) In designating a National Marine Sanctuary, the... Sanctuary includes waters within the exclusive economic zone, the Secretary shall notify the...

  7. 15 CFR 922.22 - Development of designation materials.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Development of designation materials. 922.22 Section 922.22 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade... Sanctuaries § 922.22 Development of designation materials. (a) In designating a National Marine Sanctuary,...

  8. Synthesis and design of silicide intermetallic materials

    SciTech Connect

    Petrovic, J.J.; Castro, R.G.; Butt, D.P.; Park, Y.; Hollis, K.J.; Kung, H.H.

    1998-11-01

    The overall objective of this program is to develop structural silicide-based materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation and corrosion resistance for applications of importance to the U.S. processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature materials and important applications in major energy-intensive U.S. processing industries.

  9. Design for containment of hazardous materials

    SciTech Connect

    Murray, R.C. ); McDonald, J.R. )

    1991-03-01

    Department of Energy, (DOE), facilities across the United States, use wind and tornado design and evaluation criteria based on probabilistic performance goals. In addition, other programs such as Advanced Light Water Reactors, New Production Reactors, and Individual Plant Examinations for External Events for commercial nuclear power plants utilize design and evaluation criteria based on probabilistic performance goals. The use of probabilistic performance goals is a departure from design practice for commercial nuclear power plants which have traditionally been designed utilizing a conservative specification of wind and tornado loading combined with deterministic response evaluation methods and permissible behavior limits. Approaches which utilize probabilistic wind and tornado hazard curves for specification of loading and deterministic response evaluation methods and permissible behavior limits are discussed in this paper. Through the use of such design/evaluation approaches, it may be demonstrated that there is high likelihood that probabilistic performance goals can be achieved. 14 refs., 1 fig., 5 tabs.

  10. Materials Design On-the-Fly.

    PubMed

    Cerqueira, Tiago F T; Sarmiento-Pérez, Rafael; Amsler, Maximilian; Nogueira, F; Botti, Silvana; Marques, Miguel A L

    2015-08-11

    The dream of any solid-state theorist is to be able to predict new materials with tailored properties from scratch, i.e., without any input from experiment. Over the past decades, we have steadily approached this goal. Recent developments in the field of high-throughput calculations focused on finding the best material for specific applications. However, a key input for these techniques still had to be obtained experimentally, namely, the crystal structure of the materials. Here, we give a step further and show that one can indeed optimize material properties using as a single starting point the knowledge of the periodic table and the fundamental laws of quantum mechanics. This is done by combining state-of-the-art methods of global structure prediction that allow us to obtain the ground-state crystal structure of arbitrary materials, with an evolutionary algorithm that optimizes the chemical composition for the desired property. As a first showcase demonstration of our method, we perform an unbiased search for superhard materials and for transparent conductors. We stress that our method is completely general and can be used to optimize any property (or combination of properties) that can be calculated in a computer. PMID:26574474

  11. Synthesis and design of silicide intermetallic materials

    SciTech Connect

    Petrovic, J.J.; Castro, R.G.; Butt, D.P.

    1997-04-01

    The overall objective of this program is to develop structural silicide-based materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation and corrosion resistance for applications of importance to the U.S. processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature materials and important applications in major energy-intensive U.S. processing industries. The program presently has a number of developing industrial connections, including a CRADA with Schuller International Inc. targeted at the area of MoSi{sub 2}-based high temperature materials and components for fiberglass melting and processing applications. The authors are also developing an interaction with the Institute of Gas Technology (IGT) to develop silicides for high temperature radiant gas burner applications, for the glass and other industries. Current experimental emphasis is on the development and characterization of MoSi{sub 2}-Si{sub 3}N{sub 4} and MoSi{sub 2}-SiC composites, the plasma spraying of MoSi{sub 2}-based materials, and the joining of MoSi{sub 2} materials to metals.

  12. 14 CFR 25.613 - Material strength properties and material design values.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... individual item is tested before use to determine that the actual strength properties of that particular item... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Material strength properties and material... § 25.613 Material strength properties and material design values. (a) Material strength properties...

  13. 14 CFR 25.613 - Material strength properties and material design values.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... individual item is tested before use to determine that the actual strength properties of that particular item... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Material strength properties and material... § 25.613 Material strength properties and material design values. (a) Material strength properties...

  14. 14 CFR 25.613 - Material strength properties and material design values.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... individual item is tested before use to determine that the actual strength properties of that particular item... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Material strength properties and material... § 25.613 Material strength properties and material design values. (a) Material strength properties...

  15. 14 CFR 25.613 - Material strength properties and material design values.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... individual item is tested before use to determine that the actual strength properties of that particular item... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Material strength properties and material... § 25.613 Material strength properties and material design values. (a) Material strength properties...

  16. 14 CFR 25.613 - Material strength properties and material design values.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... individual item is tested before use to determine that the actual strength properties of that particular item... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Material strength properties and material... § 25.613 Material strength properties and material design values. (a) Material strength properties...

  17. Material, process, and product design of thermoplastic composite materials

    NASA Astrophysics Data System (ADS)

    Dai, Heming

    Thermoplastic composites made of polypropylene (PP) and E-glass fibers were investigated experimentally as well as theoretically for two new classes of product designs. The first application was for reinforcement of wood. Commingled PP/glass yarn was consolidated and bonded on wood panel using a tie layer. The processing parameters, including temperature, pressure, heating time, cooling time, bonding strength, and bending strength were tested experimentally and evaluated analytically. The thermoplastic adhesive interface was investigated with environmental scanning electron microscopy. The wood/composite structural design was optimized and evaluated using a Graphic Method. In the second application, we evaluated use of thermoplastic composites for explosion containment in an arrester. PP/glass yarn was fabricated in a sleeve form and wrapped around the arrester. After consolidation, the flexible composite sleeve forms a solid composite shell. The composite shell acts as a protection layer in a surge test to contain the fragments of the arrester. The manufacturing process for forming the composite shell was designed. Woven, knitted, and braided textile composite shells made of commingled PP/glass yarn were tested and evaluated. Mechanical performance of the woven, knitted, and braided composite shells was examined analytically. The theoretical predictions were used to verify the experimental results.

  18. Thermal Characterization of Functionally Graded Materials: Design of Optimum Experiments

    NASA Technical Reports Server (NTRS)

    Cole, Kevin D.

    2003-01-01

    This paper is a study of optimal experiment design applied to the measure of thermal properties in functionally graded materials. As a first step, a material with linearly-varying thermal properties is analyzed, and several different tran- sient experimental designs are discussed. An optimality criterion, based on sen- sitivity coefficients, is used to identify the best experimental design. Simulated experimental results are analyzed to verify that the identified best experiment design has the smallest errors in the estimated parameters. This procedure is general and can be applied to design of experiments for a variety of materials.

  19. Solar optical materials for innovative window design

    SciTech Connect

    Lampert, C.M.

    1982-08-01

    New and innovative optical materials and coatings can greatly improve the efficiency of window energy systems. These potential materials and coatings increase energy efficiency by reducing radiative losses in the infrared, or reducing visible reflection losses or controlling overheating due to solar gain. Current progress in heat mirror coatings for glass and polymeric substrates is presented. Highly doped semiconducting oxides and metal/dielectric interference coatings are reviewed. Physical and optical properties are outlined for antireflection films and transparent aerogel insulation media. The potential for optical switching films as window elements includes discussions of electrochromic, photochromic and other physical switching processes.

  20. Computer-Aided Design Of Sheet-Material Parts

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffrey L.; Paternoster, Vincent Y.; Levitt, Maureen L.; Osterloh, Mark R.

    1991-01-01

    Computer-aided-design system partly automates tedious process of designing and guiding assembly of small pieces of flat sheet material into large surfaces that approximate smoothly curved surfaces having complicated three-dimensional shapes. Capability provides for flexibility enabling designer to assess quickly and easily effects of changes in design in making engineering compromises among various sizes and shapes. Saves time and money in both design and fabrication. Used in rocket-engine application and other applications requiring design of sheet-material parts.

  1. Designing Training Materials for Developing Countries.

    ERIC Educational Resources Information Center

    Rosenweig, Fred

    1984-01-01

    Describes four training guides developed by the Water and Sanitation for Health Project for use in rural water supply and sanitation projects in developing countries, explains the development process, offers insights gained from the process, and presents five considerations for designing training in third world countries. (MBR)

  2. Designed porosity materials in nuclear reactor components

    DOEpatents

    Yacout, A. M.; Pellin, Michael J.; Stan, Marius

    2016-09-06

    A nuclear fuel pellet with a porous substrate, such as a carbon or tungsten aerogel, on which at least one layer of a fuel containing material is deposited via atomic layer deposition, and wherein the layer deposition is controlled to prevent agglomeration of defects. Further, a method of fabricating a nuclear fuel pellet, wherein the method features the steps of selecting a porous substrate, depositing at least one layer of a fuel containing material, and terminating the deposition when the desired porosity is achieved. Also provided is a nuclear reactor fuel cladding made of a porous substrate, such as silicon carbide aerogel or silicon carbide cloth, upon which layers of silicon carbide are deposited.

  3. 46 CFR 58.05-1 - Material, design and construction.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... equivalent to the standards established by the ABS Steel Vessel Rules (incorporated by reference, see 46 CFR... 46 Shipping 2 2012-10-01 2012-10-01 false Material, design and construction. 58.05-1 Section 58.05... AUXILIARY MACHINERY AND RELATED SYSTEMS Main Propulsion Machinery § 58.05-1 Material, design...

  4. Evaluating Course Design Principles for Multimedia Learning Materials

    ERIC Educational Resources Information Center

    Scott, Bernard; Cong, Chunyu

    2010-01-01

    Purpose: This paper aims to report on evaluation studies of principles of course design for interactive multimedia learning materials. Design/methodology/approach: At the Defence Academy of the UK, Cranfield University has worked with military colleagues to produce multimedia learning materials for courses on "Military Knowledge". The courses are…

  5. 46 CFR 58.05-1 - Material, design and construction.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... equivalent to the standards established by the ABS Steel Vessel Rules (incorporated by reference, see 46 CFR... 46 Shipping 2 2010-10-01 2010-10-01 false Material, design and construction. 58.05-1 Section 58.05... AUXILIARY MACHINERY AND RELATED SYSTEMS Main Propulsion Machinery § 58.05-1 Material, design...

  6. Designing and modeling doubly porous polymeric materials

    NASA Astrophysics Data System (ADS)

    Ly, H.-B.; Le Droumaguet, B.; Monchiet, V.; Grande, D.

    2015-07-01

    Doubly porous organic materials based on poly(2-hydroxyethyl methacrylate) are synthetized through the use of two distinct types of porogen templates, namely a macroporogen and a nanoporogen. Two complementary strategies are implemented by using either sodium chloride particles or fused poly(methyl methacrylate) beads as macroporogens, in conjunction with ethanol as a porogenic solvent. The porogen removal respectively allows for the generation of either non-interconnected or interconnected macropores with an average diameter of about 100-200 μm and nanopores with sizes lying within the 100 nm order of magnitude, as evidenced by mercury intrusion porosimetry and scanning electron microscopy. Nitrogen sorption measurements evidence the formation of materials with rather high specific surface areas, i.e. higher than 140 m2.g-1. This paper also addresses the development of numerical tools for computing the permeability of such doubly porous materials. Due to the coexistence of well separated scales between nanopores and macropores, a consecutive double homogenization approach is proposed. A nanoscopic scale and a mesoscopic scale are introduced, and the flow is evaluated by means of the Finite Element Method to determine the macroscopic permeability. At the nanoscopic scale, the flow is described by the Stokes equations with an adherence condition at the solid surface. At the mesoscopic scale, the flow obeys the Stokes equations in the macropores and the Darcy equation in the permeable polymer in order to account for the presence of the nanopores.

  7. Concurrent materials and process selection in conceptual design

    SciTech Connect

    Kleban, S.D.

    1998-07-01

    The sequential manner in which materials and processes for a manufactured product are selected is inherently less than optimal. Designers` tendency to choose processes and materials with which they are familiar exacerbate this problem. A method for concurrent selection of materials and a joining process based on product requirements using a knowledge-based, constraint satisfaction approach is presented.

  8. Computational materials design for energy applications

    NASA Astrophysics Data System (ADS)

    Ozolins, Vidvuds

    2013-03-01

    General adoption of sustainable energy technologies depends on the discovery and development of new high-performance materials. For instance, waste heat recovery and electricity generation via the solar thermal route require bulk thermoelectrics with a high figure of merit (ZT) and thermal stability at high-temperatures. Energy recovery applications (e.g., regenerative braking) call for the development of rapidly chargeable systems for electrical energy storage, such as electrochemical supercapacitors. Similarly, use of hydrogen as vehicular fuel depends on the ability to store hydrogen at high volumetric and gravimetric densities, as well as on the ability to extract it at ambient temperatures at sufficiently rapid rates. We will discuss how first-principles computational methods based on quantum mechanics and statistical physics can drive the understanding, improvement and prediction of new energy materials. We will cover prediction and experimental verification of new earth-abundant thermoelectrics, transition metal oxides for electrochemical supercapacitors, and kinetics of mass transport in complex metal hydrides. Research has been supported by the US Department of Energy under grant Nos. DE-SC0001342, DE-SC0001054, DE-FG02-07ER46433, and DE-FC36-08GO18136.

  9. New design strategy for realizing multiferroic materials

    NASA Astrophysics Data System (ADS)

    Puggioni, Danilo; Giovannetti, Gianluca; Capone, Massimo; Rondinelli, James

    Ferroelectricity is a property that only insulating materials can exhibit. For this reason, nearly all searches for new multiferroic compounds, those simultaneously exhibiting ferroelectric and magnetic order, have focused on insulating magnetic oxides. Here, we propose a different approach: Start from a conducting oxide with broken inversion symmetry and search for routes to induce long-range magnetic order. Using density-functional and dynamical mean-field theories, we investigate the electronic properties of the polar metallic oxide LiOsO3. We show that a multiferroic state can be engineered by enclosing LiOsO3 between an insulating material, LiNbO3. We predict that the 1/1 superlattice of LiOsO3 and LiNbO3 exhibits strong coupling between magnetic and ferroelectric degrees of freedom with a ferroelectric polarization of 41.2 μCcm-2, Curie temperature of 927 K, and Néel temperature of 379 K. Our results show that one can start with polar metallic oxides to make multiferroics.

  10. Material Design, Selection, and Manufacturing Methods for System Sustainment

    SciTech Connect

    David Sowder, Jim Lula, Curtis Marshall

    2010-02-18

    This paper describes a material selection and validation process proven to be successful for manufacturing high-reliability long-life product. The National Secure Manufacturing Center business unit of the Kansas City Plant (herein called KCP) designs and manufactures complex electrical and mechanical components used in extreme environments. The material manufacturing heritage is founded in the systems design to manufacturing practices that support the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA). Material Engineers at KCP work with the systems designers to recommend materials, develop test methods, perform analytical analysis of test data, define cradle to grave needs, present final selection and fielding. The KCP material engineers typically will maintain cost control by utilizing commercial products when possible, but have the resources and to develop and produce unique formulations as necessary. This approach is currently being used to mature technologies to manufacture materials with improved characteristics using nano-composite filler materials that will enhance system design and production. For some products the engineers plan and carry out science-based life-cycle material surveillance processes. Recent examples of the approach include refurbished manufacturing of the high voltage power supplies for cockpit displays in operational aircraft; dry film lubricant application to improve bearing life for guided munitions gyroscope gimbals, ceramic substrate design for electrical circuit manufacturing, and tailored polymeric materials for various systems. The following examples show evidence of KCP concurrent design-to-manufacturing techniques used to achieve system solutions that satisfy or exceed demanding requirements.

  11. Material Compatibility with Space Storable Propellants. Design Guidebook

    NASA Technical Reports Server (NTRS)

    Uney, P. E.; Fester, D. A.

    1972-01-01

    An important consideration in the design of spacecraft for interplanetary missions is the compatibility of storage materials with the propellants. Serious problems can arise because many propellants are either extremely reactive or subject to catalytic decomposition, making the selection of proper materials of construction for propellant containment and control a critical requirement for the long-life applications. To aid in selecting materials and designing and evaluating various propulsion subsystems, available information on the compatibility of spacecraft materials with propellants of interest was compiled from literature searches and personal contacts. The compatibility of both metals and nonmetals with hydrazine, monomethyl hydrazine, nitrated hydrazine, and diborance fuels and nitrogen tetroxide, fluorine, oxygen difluoride, and Flox oxidizers was surveyed. These fuels and oxidizers encompass the wide variety of problems encountered in propellant storage. As such, they present worst case situations of the propellant affecting the material and the material affecting the propellant. This includes material attack, propellant decomposition, and the formation of clogging materials.

  12. Designing Educative Curriculum Materials: A Theoretically and Empirically Driven Process

    ERIC Educational Resources Information Center

    Davis, Elizabeth A.; Palincsar, Annemarie Sullivan; Arias, Anna Maria; Bismack, Amber Schultz; Marulis, Loren M.; Iwashyna, Stefanie K.

    2014-01-01

    In this article, the authors argue for a design process in the development of educative curriculum materials that is theoretically and empirically driven. Using a design-based research approach, they describe their design process for incorporating educative features intended to promote teacher learning into existing, high-quality curriculum…

  13. Cultivating Design Thinking in Students through Material Inquiry

    ERIC Educational Resources Information Center

    Renard, Helene

    2014-01-01

    Design thinking is a way of understanding and engaging with the world that has received much attention in academic and business circles in recent years. This article examines a hands-on learning model as a vehicle for developing design thinking capacity in students. An overview of design thinking grounds the discussion of the material-based…

  14. Intelligent decision support for polymer composite material design in an integrated design environment

    SciTech Connect

    Lenz, T.; McDowell, J.K.; Moy, D.; Sticklen, J.; Hawley, M.C.

    1994-12-31

    Previously used routine design systems which generate multiple designs for composite materials have had a strong focus on thermosets. A natural evolution of the material designer involved an expansion of the domain knowledge for possible composite material designs, as well as a re-engineering of the problem-solving structure. This was guided by an in-depth analysis of the existing material designer. The results of these analyses enabled decisions to be made regarding the adequacy of the existing problem-solving structure and identified avenues to pursue for the re-engineering of the knowledge structuring and decision processes. This reengineering and expansion to a third generation of the material designer has been completed. The third generation material designer, COMADE (Composite Material Designer), now includes an expanded thermoset and fiber material coverage; in addition, thermoplastics and discontinuous fibers have been introduced into the knowledge base. As a result, both the variables input to the system and the outputted material designs have been modified. The inclusion of this information has substantially increased the domain coverage of possible composite material designs.

  15. Center for Intelligent Fuel Cell Materials Design

    SciTech Connect

    Santurri, P.R.,; Hartmann-Thompson, C.; Keinath, S.E.

    2008-08-26

    The goal of this work was to develop a composite proton exchange membrane utilizing 1) readily available, low cost materials 2) readily modified and 3) easily processed to meet the chemical, mechanical and electrical requirements of high temperature PEM fuel cells. One of the primary goals was to produce a conducting polymer that met the criteria for strength, binding capability for additives, chemical stability, dimensional stability and good conductivity. In addition compatible, specialty nanoparticles were synthesized to provide water management and enhanced conductivity. The combination of these components in a multilayered, composite PEM has demonstrated improved conductivity at high temperatures and low humidity over commercially available polymers. The research reported in this final document has greatly increased the knowledge base related to post sulfonation of chemically and mechanically stable engineered polymers (Radel). Both electrical and strength factors for the degree of post sulfonation far exceed previous data, indicating the potential use of these materials in suitable proton exchange membrane architectures for the development of fuel cells. In addition compatible, hydrophilic, conductive nano-structures have been synthesized and incorporated into unique proton exchange membrane architectures. The use of post sulfonation for the engineered polymer and nano-particle provide cost effective techniques to produce the required components of a proton exchange membrane. The development of a multilayer proton exchange membrane as described in our work has produced a highly stable membrane at 170°C with conductivities exceeding commercially available proton exchange membranes at high temperatures and low humidity. The components and architecture of the proton exchange membrane discussed will provide low cost components for the portable market and potentially the transportation market. The development of unique components and membrane architecture

  16. Nondestructive evaluation of composite materials - A design philosophy

    NASA Technical Reports Server (NTRS)

    Duke, J. C., Jr.; Henneke, E. G., II; Stinchcomb, W. W.; Reifsnider, K. L.

    1984-01-01

    Efficient and reliable structural design utilizing fiber reinforced composite materials may only be accomplished if the materials used may be nondestructively evaluated. There are two major reasons for this requirement: (1) composite materials are formed at the time the structure is fabricated and (2) at practical strain levels damage, changes in the condition of the material, that influence the structure's mechanical performance is present. The fundamental basis of such a nondestructive evaluation capability is presented. A discussion of means of assessing nondestructively the material condition as well as a damage mechanics theory that interprets the material condition in terms of its influence on the mechanical response, stiffness, strength and life is provided.

  17. Characterization of elastomeric materials with application to design

    NASA Technical Reports Server (NTRS)

    Bower, Mark V.

    1986-01-01

    Redesign of the Space Shuttle Solid Booster has necessitated re-evaluation of the material used in the field joint O-ring seals. The viscoelastic characteristics of five candidate materials were determined. The five materials are: two fluorocarbon compounds, two nitrile compounds, and a silicon compound. The materials were tested in a uniaxial compression test to determine the characteristic relaxation functions. These tests were performed at five different temperatures. A master material curve was developed for each material from the experimental data. The results are compared to tensile relaxation tests. Application of these results to the design analysis is discussed in detail.

  18. Computational Discovery, Characterization, and Design of Single-Layer Materials

    NASA Astrophysics Data System (ADS)

    Zhuang, Houlong L.; Hennig, Richard G.

    2014-03-01

    Single-layer materials open up tremendous opportunities for applications in nanoelectronic devices and energy technologies. We first review the four components of a materials science tetrahedron for single-layer materials. We then provide a theoretical perspective of characterizing single-layer materials. This leads to a general data-mining process to predict and computationally characterize emerging single-layer materials. Finally, we comment on limitations and possible improvements of current computational procedures for the discovery, characterization, and design of single-layer materials.

  19. The automated design of materials far from equilibrium

    NASA Astrophysics Data System (ADS)

    Miskin, Marc Z.

    Automated design is emerging as a powerful concept in materials science. By combining computer algorithms, simulations, and experimental data, new techniques are being developed that start with high level functional requirements and identify the ideal materials that achieve them. This represents a radically different picture of how materials become functional in which technological demand drives material discovery, rather than the other way around. At the frontiers of this field, materials systems previously considered too complicated can start to be controlled and understood. Particularly promising are materials far from equilibrium. Material robustness, high strength, self-healing and memory are properties displayed by several materials systems that are intrinsically out of equilibrium. These and other properties could be revolutionary, provided they can first be controlled. This thesis conceptualizes and implements a framework for designing materials that are far from equilibrium. We show how, even in the absence of a complete physical theory, design from the top down is possible and lends itself to producing physical insight. As a prototype system, we work with granular materials: collections of athermal, macroscopic identical objects, since these materials function both as an essential component of industrial processes as well as a model system for many non-equilibrium states of matter. We show that by placing granular materials in the context of design, benefits emerge simultaneously for fundamental and applied interests. As first steps, we use our framework to design granular aggregates with extreme properties like high stiffness, and softness. We demonstrate control over nonlinear effects by producing exotic aggregates that stiffen under compression. Expanding on our framework, we conceptualize new ways of thinking about material design when automatic discovery is possible. We show how to build rules that link particle shapes to arbitrary granular packing

  20. Photovoltaic module encapsulation design and materials selection, volume 1

    NASA Technical Reports Server (NTRS)

    Cuddihy, E.; Carroll, W.; Coulbert, C.; Gupta, A.; Liang, R. H.

    1982-01-01

    Encapsulation material system requirements, material selection criteria, and the status and properties of encapsulation materials and processes available are presented. Technical and economic goals established for photovoltaic modules and encapsulation systems and their status are described. Available encapsulation technology and data are presented to facilitate design and material selection for silicon flat plate photovoltaic modules, using the best materials available and processes optimized for specific power applications and geographic sites. The operational and environmental loads that encapsulation system functional requirements and candidate design concepts and materials that are identified to have the best potential to meet the cost and performance goals for the flat plate solar array project are described. Available data on encapsulant material properties, fabrication processing, and module life and durability characteristics are presented.

  1. Designing Radiation Resistance in Materials for Fusion Energy

    NASA Astrophysics Data System (ADS)

    Zinkle, S. J.; Snead, L. L.

    2014-07-01

    Proposed fusion and advanced (Generation IV) fission energy systems require high-performance materials capable of satisfactory operation up to neutron damage levels approaching 200 atomic displacements per atom with large amounts of transmutant hydrogen and helium isotopes. After a brief overview of fusion reactor concepts and radiation effects phenomena in structural and functional (nonstructural) materials, three fundamental options for designing radiation resistance are outlined: Utilize matrix phases with inherent radiation tolerance, select materials in which vacancies are immobile at the design operating temperatures, or engineer materials with high sink densities for point defect recombination. Environmental and safety considerations impose several additional restrictions on potential materials systems, but reduced-activation ferritic/martensitic steels (including thermomechanically treated and oxide dispersion-strengthened options) and silicon carbide ceramic composites emerge as robust structural materials options. Materials modeling (including computational thermodynamics) and advanced manufacturing methods are poised to exert a major impact in the next ten years.

  2. Photovoltaic-module encapsulation design and materials selection: Volume 1

    SciTech Connect

    Cuddihy, E.; Carroll, W.; Coulbert, C.; Gupta, A.; Liang, R.

    1982-06-01

    Encapsulation-material system requirements, material-selection criteria, and the status and properties of encapsulation materials and processes available to the module manufacturer are presented in detail. Technical and economic goals established for photovoltaic modules and encapsulation systems and their status are described for material suppliers to assist them in assessing the suitability of materials in their product lines and the potential of new-material products. A comprehensive discussion of available encapsulation technology and data is presented to facilitate design and material selection for silicon flat-plate photovoltaic modules, using the best materials available and processes optimized for specific power applications and geographic sites. A basis is provided for specifying the operational and environmental loads that encapsulation material systems must resist. Potential deployment sites for which cost effectiveness may be achieved at a module price much greater than $0.70/W/sub p/, are also considered; data on higher-cost encapsulant materials and processes that may be in use and other material candidates that may be justified for special application are discussed. Described are encapsulation-system functional requirements and candidate design concepts and materials that have been identified and analyzed as having the best potential to meet the cost and performance goals for the Flat-Plate Solar Array Project. The available data on encapsulant material properties, fabrication processing, and module life and durability characteristics are presented.

  3. FOREWORD: Computational methodologies for designing materials Computational methodologies for designing materials

    NASA Astrophysics Data System (ADS)

    Rahman, Talat S.

    2009-02-01

    It would be fair to say that in the past few decades, theory and computer modeling have played a major role in elucidating the microscopic factors that dictate the properties of functional novel materials. Together with advances in experimental techniques, theoretical methods are becoming increasingly capable of predicting properties of materials at different length scales, thereby bringing in sight the long-sought goal of designing material properties according to need. Advances in computer technology and their availability at a reasonable cost around the world have made tit all the more urgent to disseminate what is now known about these modern computational techniques. In this special issue on computational methodologies for materials by design we have tried to solicit articles from authors whose works collectively represent the microcosm of developments in the area. This turned out to be a difficult task for a variety of reasons, not the least of which is space limitation in this special issue. Nevertheless, we gathered twenty articles that represent some of the important directions in which theory and modeling are proceeding in the general effort to capture the ability to produce materials by design. The majority of papers presented here focus on technique developments that are expected to uncover further the fundamental processes responsible for material properties, and for their growth modes and morphological evolutions. As for material properties, some of the articles here address the challenges that continue to emerge from attempts at accurate descriptions of magnetic properties, of electronically excited states, and of sparse matter, all of which demand new looks at density functional theory (DFT). I should hasten to add that much of the success in accurate computational modeling of materials emanates from the remarkable predictive power of DFT, without which we would not be able to place the subject on firm theoretical grounds. As we know and will also

  4. Design of meta-materials with novel thermoelastic properties

    NASA Astrophysics Data System (ADS)

    Watts, Seth

    The development of new techniques in micro-manufacturing in recent years has enabled the fabrication of material microstructures with essentially arbitrary designs, including those with multiple constituent materials and void space in nearly any geometry. With an essentially open design space, the onus is now on the engineer to design composite materials which are optimal for their purpose. These new materials, called meta-materials or materials with architected microstructures, offer the potential to mix and match properties in a way that exceeds that of traditional composites. We concentrate on the thermal and elastic properties of isotropic meta-materials, and design microstructures with combinations of Young's modulus, Poisson's ratio, thermal conductivity, thermal expansion, and mass density which are not found among naturally-occurring or traditional composite materials. We also produce designs with thermal expansion far below other materials. We use homogenization theory to predict the material properties of a bulk meta-material comprised of a periodic lattice of unit cells, then use topology optimization to rearrange two constituent materials and void space within the unit cell in order to extremize an objective function which yields the combinations of properties we seek. This method is quite general and can be extended to consider additional properties of interest. We constrain the design space to satisfy material isotropy directly (2D), or to satisfy cubic symmetry (3D), from which point an isotropy constraint function is easily applied. We develop and use filtering, nonlinear interpolation, and thresholding methods to render the design problem well-posed, and as a result ensure our designs are manufacturable. We have written two computer implementations of this design methodology. The first is for creating two-dimensional designs, which can run on a serial computer in approximately half an hour. The second is a parallel implementation to allow

  5. Designing high-performance layered thermoelectric materials through orbital engineering.

    PubMed

    Zhang, Jiawei; Song, Lirong; Madsen, Georg K H; Fischer, Karl F F; Zhang, Wenqing; Shi, Xun; Iversen, Bo B

    2016-01-01

    Thermoelectric technology, which possesses potential application in recycling industrial waste heat as energy, calls for novel high-performance materials. The systematic exploration of novel thermoelectric materials with excellent electronic transport properties is severely hindered by limited insight into the underlying bonding orbitals of atomic structures. Here we propose a simple yet successful strategy to discover and design high-performance layered thermoelectric materials through minimizing the crystal field splitting energy of orbitals to realize high orbital degeneracy. The approach naturally leads to design maps for optimizing the thermoelectric power factor through forming solid solutions and biaxial strain. Using this approach, we predict a series of potential thermoelectric candidates from layered CaAl2Si2-type Zintl compounds. Several of them contain nontoxic, low-cost and earth-abundant elements. Moreover, the approach can be extended to several other non-cubic materials, thereby substantially accelerating the screening and design of new thermoelectric materials. PMID:26948043

  6. Designing high-performance layered thermoelectric materials through orbital engineering

    NASA Astrophysics Data System (ADS)

    Zhang, Jiawei; Song, Lirong; Madsen, Georg K. H.; Fischer, Karl F. F.; Zhang, Wenqing; Shi, Xun; Iversen, Bo B.

    2016-03-01

    Thermoelectric technology, which possesses potential application in recycling industrial waste heat as energy, calls for novel high-performance materials. The systematic exploration of novel thermoelectric materials with excellent electronic transport properties is severely hindered by limited insight into the underlying bonding orbitals of atomic structures. Here we propose a simple yet successful strategy to discover and design high-performance layered thermoelectric materials through minimizing the crystal field splitting energy of orbitals to realize high orbital degeneracy. The approach naturally leads to design maps for optimizing the thermoelectric power factor through forming solid solutions and biaxial strain. Using this approach, we predict a series of potential thermoelectric candidates from layered CaAl2Si2-type Zintl compounds. Several of them contain nontoxic, low-cost and earth-abundant elements. Moreover, the approach can be extended to several other non-cubic materials, thereby substantially accelerating the screening and design of new thermoelectric materials.

  7. Designing high-performance layered thermoelectric materials through orbital engineering

    PubMed Central

    Zhang, Jiawei; Song, Lirong; Madsen, Georg K. H.; Fischer, Karl F. F.; Zhang, Wenqing; Shi, Xun; Iversen, Bo B.

    2016-01-01

    Thermoelectric technology, which possesses potential application in recycling industrial waste heat as energy, calls for novel high-performance materials. The systematic exploration of novel thermoelectric materials with excellent electronic transport properties is severely hindered by limited insight into the underlying bonding orbitals of atomic structures. Here we propose a simple yet successful strategy to discover and design high-performance layered thermoelectric materials through minimizing the crystal field splitting energy of orbitals to realize high orbital degeneracy. The approach naturally leads to design maps for optimizing the thermoelectric power factor through forming solid solutions and biaxial strain. Using this approach, we predict a series of potential thermoelectric candidates from layered CaAl2Si2-type Zintl compounds. Several of them contain nontoxic, low-cost and earth-abundant elements. Moreover, the approach can be extended to several other non-cubic materials, thereby substantially accelerating the screening and design of new thermoelectric materials. PMID:26948043

  8. Designing synthetic materials to control stem cell phenotype

    PubMed Central

    Saha, Krishanu; Pollock, Jacob F.; Schaffer, David V.; Healy, Kevin E.

    2007-01-01

    Summary The microenvironment in which stem cells reside regulates their fate, and synthetic materials have recently been designed to emulate these regulatory processes for various medical applications. Ligands inspired by the natural extracellular matrix, cell-cell contacts, and growth factors have been incorporated into synthetic materials with precisely engineered density and presentation. Furthermore, material architecture and mechanical properties are material design parameters that provide a context for receptor-ligand interactions and thereby contribute to fate determination of uncommitted stem cells. While significant progress has been made in biomaterials development for cellular control, the design of more sophisticated and robust synthetic materials can address future challenges in achieving spatiotemporally control of cellular phenotype and in implementing histocompatible clinical therapies. PMID:17669680

  9. Evaluation of materials and design modifications for aircraft brakes

    NASA Technical Reports Server (NTRS)

    Ho, T. L.; Kennedy, F. E.; Peterson, M. B.

    1975-01-01

    A test program is described which was carried out to evaluate several proposed design modifications and several high-temperature friction materials for use in aircraft disk brakes. The evaluation program was carried out on a specially built test apparatus utilizing a disk brake and wheel half from a small het aircraft. The apparatus enabled control of brake pressure, velocity, and braking time. Tests were run under both constant and variable velocity conditions and covered a kinetic energy range similar to that encountered in aircraft brake service. The results of the design evaluation program showed that some improvement in brake performance can be realized by making design changes in the components of the brake containing friction material. The materials evaluation showed that two friction materials show potential for use in aircraft disk brakes. One of the materials is a nickel-based sintered composite, while the other is a molybdenum-based material. Both materials show much lower wear rates than conventional copper-based materials and are better able to withstand the high temperatures encountered during braking. Additional materials improvement is necessary since both materials show a significant negative slope of the friction-velocity curve at low velocities.

  10. The composite materials handbook (MIL handbook 17). Volume 3: Materials usage, design, and analysis

    SciTech Connect

    Not Available

    1999-01-01

    The Composite Materials Handbook (MIL Handbook 17) is THE source for data and usage guidelines for current and emerging polymer matrix composite materials. It provides you with the tools you will need to design and fabricate end items from polymer matrix composite materials and offers guidelines for how these data should be generated and used. The Handbook is a comprehensive guide of composites technology and engineering, an area that is advancing and changing rapidly. Volume 3 discusses usage of the data for material procurement, quality control, design, structural analysis, and reliability. The material scope is continuous-fiber-reinforced polymer matrix composites for all applications.

  11. Designing Radiation Resistance in Materials for Fusion Energy

    SciTech Connect

    Zinkle, Steven J; Snead, Lance Lewis

    2014-01-01

    Proposed fusion and advanced (Generation IV) fission energy systems require high performance materials capable of satisfactory operation up to neutron damage levels approaching 200 atomic displacements per atom with large amounts of transmutant hydrogen and helium isotopes. After a brief overview of fusion reactor concepts and radiation effects phenomena in structural and functional (non-structural) materials, three fundamental options for designing radiation resistance are outlined: Utilize matrix phases with inherent radiation tolerance, select materials where vacancies are immobile at the design operating temperatures, or construct high densities of point defect recombination sinks. Environmental and safety considerations impose several additional restrictions on potential materials systems, but reduced activation ferritic/martensitic steels (including thermomechanically treated and oxide dispersion strengthened options) and silicon carbide ceramic composites emerge as robust structural materials options. Materials modeling (including computational thermodynamics) and advanced manufacturing methods are poised to exert a major impact in the next ten years.

  12. Implications of material selection on the design of packaging machinery.

    PubMed

    Merritt, J P

    2009-01-01

    Material selection has significant implications on the design and cost of horizontal-form-fill-seal packaging machinery. To avoid excessive costs, machine redesigns and project delays, material selection must be reconciled early in the project and revisited throughout the construction of the machine. PMID:19405337

  13. Sculpture: Creative Designs with Modern Materials (Tentative Course Outline).

    ERIC Educational Resources Information Center

    Dubocq, Edward R.

    This document reports on a course in comprehension and application of various techniques of sculpture and collage, using a contemporary point of view. Students will work with contemporary materials such as wood, metals, plaster, plastics, styrofoam, and many other cardboard basic materials suitable for creative design products. This unit will…

  14. Current Materials on Barrier-Free Design. Revised.

    ERIC Educational Resources Information Center

    National Easter Seal Society for Crippled Children and Adults, Chicago, IL.

    An eight-page annotated bibliography contains material available from the National Easter Seal Society and current material available from other sources. The annotations are grouped under design, guides, planning resources, standards/legislation, and general. Ordering information is provided. (MLF)

  15. Design Guidelines for Digital Learning Material for Food Chemistry Education.

    ERIC Educational Resources Information Center

    Diederen, Julia; Gruppen, Harry; Voragen, Alphons G. J.; Hartog, Rob; Mulder, Martin; Biemans, Harm

    This paper describes the first stage of a 4-year research project on the design, development and use of Web-based digital learning material for food chemistry education. The paper discusses design guidelines, based on principles that were selected from theories on learning and instruction, and illustrates in detail how these guidelines were used…

  16. Structure-Based Design of Functional Amyloid Materials

    SciTech Connect

    Li, Dan; Jones, Eric M.; Sawaya, Michael R.; Furukawa, Hiroyasu; Luo, Fang; Ivanova, Magdalena; Sievers, Stuart A.; Wang, Wenyuan; Yaghi, Omar M.; Liu, Cong; Eisenberg, David S.

    2014-12-04

    We report that amyloid fibers, once exclusively associated with disease, are acquiring utility as a class of biological nanomaterials. We introduce a method that utilizes the atomic structures of amyloid peptides, to design materials with versatile applications. As a model application, we designed amyloid fibers capable of capturing carbon dioxide from flue gas, to address the global problem of excess anthropogenic carbon dioxide. By measuring dynamic separation of carbon dioxide from nitrogen, we show that fibers with designed amino acid sequences double the carbon dioxide binding capacity of the previously reported fiber formed by VQIVYK from Tau protein. In a second application, we designed fibers that facilitate retroviral gene transfer. Finally, by measuring lentiviral transduction, we show that designed fibers exceed the efficiency of polybrene, a commonly used enhancer of transduction. The same procedures can be adapted to the design of countless other amyloid materials with a variety of properties and uses.

  17. Structure-Based Design of Functional Amyloid Materials

    DOE PAGESBeta

    Li, Dan; Jones, Eric M.; Sawaya, Michael R.; Furukawa, Hiroyasu; Luo, Fang; Ivanova, Magdalena; Sievers, Stuart A.; Wang, Wenyuan; Yaghi, Omar M.; Liu, Cong; et al

    2014-12-04

    We report that amyloid fibers, once exclusively associated with disease, are acquiring utility as a class of biological nanomaterials. We introduce a method that utilizes the atomic structures of amyloid peptides, to design materials with versatile applications. As a model application, we designed amyloid fibers capable of capturing carbon dioxide from flue gas, to address the global problem of excess anthropogenic carbon dioxide. By measuring dynamic separation of carbon dioxide from nitrogen, we show that fibers with designed amino acid sequences double the carbon dioxide binding capacity of the previously reported fiber formed by VQIVYK from Tau protein. In amore » second application, we designed fibers that facilitate retroviral gene transfer. Finally, by measuring lentiviral transduction, we show that designed fibers exceed the efficiency of polybrene, a commonly used enhancer of transduction. The same procedures can be adapted to the design of countless other amyloid materials with a variety of properties and uses.« less

  18. Rational design of inorganic dielectric materials with expected permittivity.

    PubMed

    Xie, Congwei; Oganov, Artem R; Dong, Dong; Liu, Ning; Li, Duan; Debela, Tekalign Terfa

    2015-01-01

    Techniques for rapid design of dielectric materials with appropriate permittivity for many important technological applications are urgently needed. It is found that functional structure blocks (FSBs) are helpful in rational design of inorganic dielectrics with expected permittivity. To achieve this, coordination polyhedra are parameterized as FSBs and a simple empirical model to evaluate permittivity based on these FSB parameters is proposed. Using this model, a wide range of examples including ferroelectric, high/low permittivity materials are discussed, resulting in several candidate materials for experimental follow-up. PMID:26617342

  19. Rational design of inorganic dielectric materials with expected permittivity

    PubMed Central

    Xie, Congwei; Oganov, Artem R.; Dong, Dong; Liu, Ning; Li, Duan; Debela, Tekalign Terfa

    2015-01-01

    Techniques for rapid design of dielectric materials with appropriate permittivity for many important technological applications are urgently needed. It is found that functional structure blocks (FSBs) are helpful in rational design of inorganic dielectrics with expected permittivity. To achieve this, coordination polyhedra are parameterized as FSBs and a simple empirical model to evaluate permittivity based on these FSB parameters is proposed. Using this model, a wide range of examples including ferroelectric, high/low permittivity materials are discussed, resulting in several candidate materials for experimental follow-up. PMID:26617342

  20. Rational design of inorganic dielectric materials with expected permittivity

    NASA Astrophysics Data System (ADS)

    Xie, Congwei; Oganov, Artem R.; Dong, Dong; Liu, Ning; Li, Duan; Debela, Tekalign Terfa

    2015-11-01

    Techniques for rapid design of dielectric materials with appropriate permittivity for many important technological applications are urgently needed. It is found that functional structure blocks (FSBs) are helpful in rational design of inorganic dielectrics with expected permittivity. To achieve this, coordination polyhedra are parameterized as FSBs and a simple empirical model to evaluate permittivity based on these FSB parameters is proposed. Using this model, a wide range of examples including ferroelectric, high/low permittivity materials are discussed, resulting in several candidate materials for experimental follow-up.

  1. Revisiting the Balazs thought experiment in the case of a left-handed material: electromagnetic-pulse-induced displacement of a dispersive, dissipative negative-index slab.

    PubMed

    Chau, Kenneth J; Lezec, Henri J

    2012-04-23

    We propose a set of postulates to describe the mechanical interaction between a plane-wave electromagnetic pulse and a dispersive, dissipative slab having a refractive index of arbitrary sign. The postulates include the Abraham electromagnetic momentum density, a generalized Lorentz force law, and a model for absorption-driven mass transfer from the pulse to the medium. These opto-mechanical mechanisms are incorporated into a one-dimensional finite-difference time-domain algorithm that solves Maxwell's equations and calculates the instantaneous force densities exerted by the pulse onto the slab, the momentum-per-unit-area of the pulse and slab, and the trajectories of the slab and system center-of-mass. We show that the postulates are consistent with conservation of global energy, momentum, and center-of-mass velocity at all times, even for cases in which the refractive index of the slab is negative or zero. Consistency between the set of postulates and well-established conservation laws reinforces the Abraham momentum density as the one true electromagnetic momentum density and enables, for the first time, identification of the correct form of the electromagnetic mass density distribution and development of an explicit model for mass transfer due to absorption, for the most general case of a ponderable medium that is both dispersive and dissipative. PMID:22535106

  2. Structural and Machine Design Using Piezoceramic Materials: A Guide for Structural Design Engineers

    NASA Technical Reports Server (NTRS)

    Inman, Daniel J.; Cudney, Harley H.

    2000-01-01

    Using piezoceramic materials is one way the design engineer can create structures which have an ability to both sense and respond to their environment. Piezoceramic materials can be used to create structural sensors and structural actuators. Because piezoceramic materials have transduction as a material property, their sensing or actuation functions are a result of what happens to the material. This is different than discrete devices we might attach to the structure. For example, attaching an accelerometer to a structure will yield an electrical signal proportional to the acceleration at the attachment point on the structure. Using a electromagnetic shaker as an actuator will create an applied force at the attachment point. Active material elements in a structural design are not easily modeled as providing transduction at a point, but rather they change the physics of the structure in the areas where they are used. Hence, a designer must not think of adding discrete devices to a structure to obtain an effect, but rather must design a structural system which accounts for the physical principles of all the elements in the structure. The purpose of this manual is to provide practicing engineers the information necessary to incorporate piezoelectric materials in structural design and machine design. First, we will review the solid-state physics of piezoelectric materials. Then we will discuss the physical characteristics of the electrical-active material-structural system. We will present the elements of this system which must be considered as part of the design task for a structural engineer. We will cover simple modeling techniques and review the features and capabilities of commercial design tools that are available. We will then cover practical how-to elements of working with piezoceramic materials. We will review sources of piezoceramic materials and built-up devices, and their characteristics. Finally, we will provide two design examples using piezoceramic

  3. Evolution of heavy duty engine valves - materials and design

    SciTech Connect

    Schaefer, S.K.; Larson, J.M.; Jenkins, L.F.; Wang, Y.

    1997-12-31

    Engine poppet valves control gas flow in internal combustion engines. The combustion event and the flow of the gases formed past the valve during the intake or exhaust portion of the combustion cycle, expose heavy duty diesel valves to high temperatures, oxidizing or corroding atmospheres and high stresses from firing and seating. This paper is a review of heavy duty diesel engine valve material and design evolution over the last fifty years in North America. The primary driving forces behind the evolution have historically been the need for improved durability and more cost effective designs. However, in recent years engine emission regulatory requirements have become an equally important influence on valve material selection and design. The paper also endeavors to predict how heavy duty diesel engine valve materials and designs may change in response to these driving forces in the foreseeable future.

  4. Microstructural design of cellular materials I: Honeycomb beams and plates

    SciTech Connect

    Huang, J.S.; Gibson, L.J.

    1992-06-01

    Performance indices for materials describe the mechanical efficiency of a component under a given mode of loading: The higher the performance index, the lower the mass of the component for a given mechanical requirement. Material selection charts (Ashby, 1989) offer a graphical means of comparing performance indices for a wide range of materials. Performance indices are described. Micromechanical models for behaviour of cellular materials are used to suggest novel microstructural designs for cellular materials with improved performance. Three novel microstructural designs, described in companion papers, have been fabricated and tested. Results of the tests indicate that the new microstructures have higher values of some performance indices than those of the solids from which they are made.

  5. Physics towards next generation Li secondary batteries materials: A short review from computational materials design perspective

    NASA Astrophysics Data System (ADS)

    Ouyang, ChuYing; Chen, LiQuan

    2013-12-01

    The physics that associated with the performance of lithium secondary batteries (LSB) are reviewed. The key physical problems in LSB include the electronic conduction mechanism, kinetics and thermodynamics of lithium ion migration, electrode/ electrolyte surface/interface, structural (phase) and thermodynamics stability of the electrode materials, physics of intercalation and deintercalation. The relationship between the physical/chemical nature of the LSB materials and the batteries performance is summarized and discussed. A general thread of computational materials design for LSB materials is emphasized concerning all the discussed physics problems. In order to fasten the progress of the new materials discovery and design for the next generation LSB, the Materials Genome Initiative (MGI) for LSB materials is a promising strategy and the related requirements are highlighted.

  6. Optimal shielding design for minimum materials cost or mass

    DOE PAGESBeta

    Woolley, Robert D.

    2015-12-02

    The mathematical underpinnings of cost optimal radiation shielding designs based on an extension of optimal control theory are presented, a heuristic algorithm to iteratively solve the resulting optimal design equations is suggested, and computational results for a simple test case are discussed. A typical radiation shielding design problem can have infinitely many solutions, all satisfying the problem's specified set of radiation attenuation requirements. Each such design has its own total materials cost. For a design to be optimal, no admissible change in its deployment of shielding materials can result in a lower cost. This applies in particular to very smallmore » changes, which can be restated using the calculus of variations as the Euler-Lagrange equations. Furthermore, the associated Hamiltonian function and application of Pontryagin's theorem lead to conditions for a shield to be optimal.« less

  7. Optimal shielding design for minimum materials cost or mass

    SciTech Connect

    Woolley, Robert D.

    2015-12-02

    The mathematical underpinnings of cost optimal radiation shielding designs based on an extension of optimal control theory are presented, a heuristic algorithm to iteratively solve the resulting optimal design equations is suggested, and computational results for a simple test case are discussed. A typical radiation shielding design problem can have infinitely many solutions, all satisfying the problem's specified set of radiation attenuation requirements. Each such design has its own total materials cost. For a design to be optimal, no admissible change in its deployment of shielding materials can result in a lower cost. This applies in particular to very small changes, which can be restated using the calculus of variations as the Euler-Lagrange equations. Furthermore, the associated Hamiltonian function and application of Pontryagin's theorem lead to conditions for a shield to be optimal.

  8. Perspective: Role of structure prediction in materials discovery and design

    NASA Astrophysics Data System (ADS)

    Needs, Richard J.; Pickard, Chris J.

    2016-05-01

    Materials informatics owes much to bioinformatics and the Materials Genome Initiative has been inspired by the Human Genome Project. But there is more to bioinformatics than genomes, and the same is true for materials informatics. Here we describe the rapidly expanding role of searching for structures of materials using first-principles electronic-structure methods. Structure searching has played an important part in unraveling structures of dense hydrogen and in identifying the record-high-temperature superconducting component in hydrogen sulfide at high pressures. We suggest that first-principles structure searching has already demonstrated its ability to determine structures of a wide range of materials and that it will play a central and increasing part in materials discovery and design.

  9. Conceptual Design Report for the Irradiated Materials Characterization Laboratory (IMCL)

    SciTech Connect

    Stephanie Austad

    2010-06-01

    This document describes the design at a conceptual level for the Irradiated Materials Characterization Laboratory (IMCL) to be located at the Materials and Fuels Complex (MFC) at the Idaho National Laboratory (INL). The IMCL is an 11,000-ft2, Hazard Category-2 nuclear facility that is designed for use as a state of the-art nuclear facility for the purpose of hands-on and remote handling, characterization, and examination of irradiated and nonirradiated nuclear material samples. The IMCL will accommodate a series of future, modular, and reconfigurable instrument enclosures or caves. To provide a bounding design basis envelope for the facility-provided space and infrastructure, an instrument enclosure or cave configuration was developed and is described in some detail. However, the future instrument enclosures may be modular, integral with the instrument, or reconfigurable to enable various characterization environments to be configured as changes in demand occur. They are not provided as part of the facility.

  10. Optimal Experiment Design for Thermal Characterization of Functionally Graded Materials

    NASA Technical Reports Server (NTRS)

    Cole, Kevin D.

    2003-01-01

    The purpose of the project was to investigate methods to accurately verify that designed , materials meet thermal specifications. The project involved heat transfer calculations and optimization studies, and no laboratory experiments were performed. One part of the research involved study of materials in which conduction heat transfer predominates. Results include techniques to choose among several experimental designs, and protocols for determining the optimum experimental conditions for determination of thermal properties. Metal foam materials were also studied in which both conduction and radiation heat transfer are present. Results of this work include procedures to optimize the design of experiments to accurately measure both conductive and radiative thermal properties. Detailed results in the form of three journal papers have been appended to this report.

  11. High-throughput theoretical design of lithium battery materials

    NASA Astrophysics Data System (ADS)

    Shi-Gang, Ling; Jian, Gao; Rui-Juan, Xiao; Li-Quan, Chen

    2016-01-01

    The rapid evolution of high-throughput theoretical design schemes to discover new lithium battery materials is reviewed, including high-capacity cathodes, low-strain cathodes, anodes, solid state electrolytes, and electrolyte additives. With the development of efficient theoretical methods and inexpensive computers, high-throughput theoretical calculations have played an increasingly important role in the discovery of new materials. With the help of automatic simulation flow, many types of materials can be screened, optimized and designed from a structural database according to specific search criteria. In advanced cell technology, new materials for next generation lithium batteries are of great significance to achieve performance, and some representative criteria are: higher energy density, better safety, and faster charge/discharge speed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11234013 and 51172274) and the National High Technology Research and Development Program of China (Grant No. 2015AA034201).

  12. Soft computing in design and manufacturing of advanced materials

    NASA Technical Reports Server (NTRS)

    Cios, Krzysztof J.; Baaklini, George Y; Vary, Alex

    1993-01-01

    The potential of fuzzy sets and neural networks, often referred to as soft computing, for aiding in all aspects of manufacturing of advanced materials like ceramics is addressed. In design and manufacturing of advanced materials, it is desirable to find which of the many processing variables contribute most to the desired properties of the material. There is also interest in real time quality control of parameters that govern material properties during processing stages. The concepts of fuzzy sets and neural networks are briefly introduced and it is shown how they can be used in the design and manufacturing processes. These two computational methods are alternatives to other methods such as the Taguchi method. The two methods are demonstrated by using data collected at NASA Lewis Research Center. Future research directions are also discussed.

  13. Segmented molecular design of self-healing proteinaceous materials

    PubMed Central

    Sariola, Veikko; Pena-Francesch, Abdon; Jung, Huihun; Çetinkaya, Murat; Pacheco, Carlos; Sitti, Metin; Demirel, Melik C.

    2015-01-01

    Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure–property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials. PMID:26323335

  14. Segmented molecular design of self-healing proteinaceous materials.

    PubMed

    Sariola, Veikko; Pena-Francesch, Abdon; Jung, Huihun; Çetinkaya, Murat; Pacheco, Carlos; Sitti, Metin; Demirel, Melik C

    2015-01-01

    Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure-property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials. PMID:26323335

  15. Segmented molecular design of self-healing proteinaceous materials

    NASA Astrophysics Data System (ADS)

    Sariola, Veikko; Pena-Francesch, Abdon; Jung, Huihun; Çetinkaya, Murat; Pacheco, Carlos; Sitti, Metin; Demirel, Melik C.

    2015-09-01

    Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure-property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials.

  16. Computational Design of 2D materials for Energy Applications

    NASA Astrophysics Data System (ADS)

    Sun, Qiang

    2015-03-01

    Since the successful synthesis of graphene, tremendous efforts have been devoted to two-dimensional monolayers such as boron nitride (BN), silicene and MoS2. These 2D materials exhibit a large variety of physical and chemical properties with unprecedented applications. Here we report our recent studies of computational design of 2D materials for fuel cell applications which include hydrogen storage, CO2 capture, CO conversion and O2 reduction.

  17. Concurrent materials and process selection in conceptual design

    SciTech Connect

    Kleban, Stephen D.; Knorovsky, Gerald A.

    2000-08-16

    A method for concurrent selection of materials and a joining process based on product requirements using a knowledge-based, constraint satisfaction approach facilitates the product design and manufacturing process. Using a Windows-based computer video display and a data base of materials and their properties, the designer can ascertain the preferred composition of two parts based on various operating/environmental constraints such as load, temperature, lifetime, etc. Optimum joinder of the two parts may simultaneously be determined using a joining process data base based upon the selected composition of the components as well as the operating/environmental constraints.

  18. Reticular synthesis and the design of new materials.

    PubMed

    Yaghi, Omar M; O'Keeffe, Michael; Ockwig, Nathan W; Chae, Hee K; Eddaoudi, Mohamed; Kim, Jaheon

    2003-06-12

    The long-standing challenge of designing and constructing new crystalline solid-state materials from molecular building blocks is just beginning to be addressed with success. A conceptual approach that requires the use of secondary building units to direct the assembly of ordered frameworks epitomizes this process: we call this approach reticular synthesis. This chemistry has yielded materials designed to have predetermined structures, compositions and properties. In particular, highly porous frameworks held together by strong metal-oxygen-carbon bonds and with exceptionally large surface area and capacity for gas storage have been prepared and their pore metrics systematically varied and functionalized. PMID:12802325

  19. Designer disordered materials with large, complete photonic band gaps

    PubMed Central

    Florescu, Marian; Torquato, Salvatore; Steinhardt, Paul J.

    2009-01-01

    We present designs of 2D, isotropic, disordered, photonic materials of arbitrary size with complete band gaps blocking all directions and polarizations. The designs with the largest band gaps are obtained by a constrained optimization method that starts from a hyperuniform disordered point pattern, an array of points whose number variance within a spherical sampling window grows more slowly than the volume. We argue that hyperuniformity, combined with uniform local topology and short-range geometric order, can explain how complete photonic band gaps are possible without long-range translational order. We note the ramifications for electronic and phononic band gaps in disordered materials. PMID:19918087

  20. LUTE primary mirror materials and design study report

    NASA Technical Reports Server (NTRS)

    Ruthven, Greg

    1993-01-01

    The major objective of the Lunar Ultraviolet Telescope Experiment (LUTE) Primary Mirror Materials and Design Study is to investigate the feasibility of the LUTE telescope primary mirror. A systematic approach to accomplish this key goal was taken by first understanding the optical, thermal, and structural requirements and then deriving the critical primary mirror-level requirements for ground testing, launch, and lunar operations. After summarizing the results in those requirements which drove the selection of material and the design for the primary mirror are discussed. Most important of these are the optical design which was assumed to be the MSFC baseline (i.e. 3 mirror optical system), telescope wavefront error (WFE) allocations, the telescope weight budget, and the LUTE operational temperature ranges. Mechanical load levels, reflectance and microroughness issues, and options for the LUTE metering structure were discussed and an outline for the LUTE telescope sub-system design specification was initiated. The primary mirror analysis and results are presented. The six material substrate candidates are discussed and four distinct mirror geometries which are considered are shown. With these materials and configurations together with varying the location of the mirror support points, a total of 42 possible primary mirror designs resulted. The polishability of each substrate candidate was investigated and a usage history of 0.5 meter and larger precision cryogenic mirrors (the operational low end LUTE temperature of 60 K is the reason we feel a survey of cryogenic mirrors is appropriate) that were flown or tested are presented.

  1. Optimum weight design of functionally graded material gears

    NASA Astrophysics Data System (ADS)

    Jing, Shikai; Zhang, He; Zhou, Jingtao; Song, Guohua

    2015-11-01

    Traditional gear weight optimization methods consider gear tooth number, module, face width or other dimension parameters of gear as design variables. However, due to the complicated form and geometric features peculiar to the gear, there will be large amounts of design parameters in gear design, and the influences of gear parameters changing on gear trains, transmission system and the whole equipment have to be taken into account, which increases the complexity of optimization problem. This paper puts forward to apply functionally graded materials (FGMs) to gears and then conduct the optimization. According to the force situation of gears, the material distribution form of FGM gears is determined. Then based on the performance parameters analysis of FGMs and the practical working demands for gears, a multi-objective optimization model is formed. Finally by using the goal driven optimization (GDO) method, the optimal material distribution is achieved, which makes gear weight and the maximum deformation be minimum and the maximum bending stress do not exceed the allowable stress. As an example, the applying of FGM to automotive transmission gear is conducted to illustrate the optimization design process and the result shows that under the condition of keeping the normal working performance of gear, the method achieves in greatly reducing the gear weight. This research proposes a FGM gears design method that is able to largely reduce the weight of gears by optimizing the microscopic material parameters instead of changing the macroscopic dimension parameters of gears, which reduces the complexity of gear weight optimization problem.

  2. The Cam Shell: An Innovative Design With Materials and Manufacturing

    NASA Technical Reports Server (NTRS)

    Chung, W. Richard; Larsen, Frank M.; Kornienko, Rob

    2003-01-01

    Most of the personal audio and video recording devices currently sold on the open market all require hands to operate. Little consideration was given to designing a hands-free unit. Such a system once designed and made available to the public could greatly benefit mobile police officers, bicyclists, adventurers, street and dirt motorcyclists, horseback riders and many others. With a few design changes water sports and skiing activities could be another large area of application. The cam shell is an innovative design in which an audio and video recording device (such as palm camcorder) is housed in a body-mounted protection system. This system is based on the concept of viewing and recording at the same time. A view cam is attached to a helmet wired to a recording unit encased in a transparent body-mounted protection system. The helmet can also be controlled by remote. The operator will have full control in recording everything. However, the recording unit will be operated completely hands-free. This project will address the design considerations and their effects on material selection and manufacturing. It will enhance the understanding of the structure of materials, and how the structure affects the behavior of the material, and the role that processing play in linking the relationship between structure and properties. A systematic approach to design feasibility study, cost analysis and problem solving will also be discussed.

  3. Designing Silk-silk Protein Alloy Materials for Biomedical Applications

    PubMed Central

    Hu, Xiao; Duki, Solomon; Forys, Joseph; Hettinger, Jeffrey; Buchicchio, Justin; Dobbins, Tabbetha; Yang, Catherine

    2014-01-01

    Fibrous proteins display different sequences and structures that have been used for various applications in biomedical fields such as biosensors, nanomedicine, tissue regeneration, and drug delivery. Designing materials based on the molecular-scale interactions between these proteins will help generate new multifunctional protein alloy biomaterials with tunable properties. Such alloy material systems also provide advantages in comparison to traditional synthetic polymers due to the materials biodegradability, biocompatibility, and tenability in the body. This article used the protein blends of wild tussah silk (Antheraea pernyi) and domestic mulberry silk (Bombyx mori) as an example to provide useful protocols regarding these topics, including how to predict protein-protein interactions by computational methods, how to produce protein alloy solutions, how to verify alloy systems by thermal analysis, and how to fabricate variable alloy materials including optical materials with diffraction gratings, electric materials with circuits coatings, and pharmaceutical materials for drug release and delivery. These methods can provide important information for designing the next generation multifunctional biomaterials based on different protein alloys. PMID:25145602

  4. Turning statistical physics models into materials design engines.

    PubMed

    Miskin, Marc Z; Khaira, Gurdaman; de Pablo, Juan J; Jaeger, Heinrich M

    2016-01-01

    Despite the success statistical physics has enjoyed at predicting the properties of materials for given parameters, the inverse problem, identifying which material parameters produce given, desired properties, is only beginning to be addressed. Recently, several methods have emerged across disciplines that draw upon optimization and simulation to create computer programs that tailor material responses to specified behaviors. However, so far the methods developed either involve black-box techniques, in which the optimizer operates without explicit knowledge of the material's configuration space, or require carefully tuned algorithms with applicability limited to a narrow subclass of materials. Here we introduce a formalism that can generate optimizers automatically by extending statistical mechanics into the realm of design. The strength of this approach lies in its capability to transform statistical models that describe materials into optimizers to tailor them. By comparing against standard black-box optimization methods, we demonstrate how optimizers generated by this formalism can be faster and more effective, while remaining straightforward to implement. The scope of our approach includes possibilities for solving a variety of complex optimization and design problems concerning materials both in and out of equilibrium. PMID:26684770

  5. Force field development from first principles for materials design

    NASA Astrophysics Data System (ADS)

    Chan, Maria; Kinaci, Alper; Narayanan, Badri; Sen, Fatih; Gray, Stephen; Davis, Michael; Sankaranaryanan, Subramanian

    2015-03-01

    The ability to perform accurate calculations efficiently is crucial for computational materials design. In this talk, we will discuss a stream-lined approach to force field development using first principles density functional theory training data and machine learning algorithms. We will also discuss the validation of this approach on precious metal nanoparticles.

  6. Designing ICT Training Material for Chinese Language Arts Teachers.

    ERIC Educational Resources Information Center

    Lin, Janet Mei-Chuen; Wu, Cheng-Chih; Chen, Hsiu-Yen

    The purpose of this research is to tailor the design of information and communications technology (ICT) training material to the needs of Chinese language arts teachers such that the training they receive will be conducive to effective integration of ICT into instruction. Eighteen experienced teachers participated in a Delphi-like survey that…

  7. Technology-Enhanced EFL Syllabus Design and Materials Development

    ERIC Educational Resources Information Center

    Nguyen, Long V.

    2008-01-01

    In this paper, I am going to look at the issues of TESOL from one major critical point of view: How the use of the Internet technology might influence TESOL syllabus design and materials development. The article attempts to investigate some possibilities and opportunities provided by the Internet, focusing on the World Wide Web (WWW) as credible…

  8. 46 CFR 58.05-1 - Material, design and construction.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... equivalent to the standards established by the ABS Steel Vessel Rules (incorporated by reference, see 46 CFR... 46 Shipping 2 2014-10-01 2014-10-01 false Material, design and construction. 58.05-1 Section 58.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN...

  9. 46 CFR 58.05-1 - Material, design and construction.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... equivalent to the standards established by the ABS Steel Vessel Rules (incorporated by reference, see 46 CFR... 46 Shipping 2 2013-10-01 2013-10-01 false Material, design and construction. 58.05-1 Section 58.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN...

  10. 46 CFR 58.05-1 - Material, design and construction.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... equivalent to the standards established by the ABS Steel Vessel Rules (incorporated by reference, see 46 CFR... 46 Shipping 2 2011-10-01 2011-10-01 false Material, design and construction. 58.05-1 Section 58.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN...

  11. Design of nanoporous materials with optimal sorption capacity

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Urita, Koki; Moriguchi, Isamu; Tartakovsky, Daniel M.

    2015-06-01

    Modern technological advances have enabled one to manufacture nanoporous materials with a prescribed pore structure. This raises a possibility of using controllable pore-scale parameters (e.g., pore size and connectivity) to design materials with desired macroscopic properties (e.g., diffusion coefficient and adsorption capacity). By relating these two scales, the homogenization theory (or other upscaling techniques) provides a means of guiding the experimental design. To demonstrate this approach, we consider a class of nanoporous materials whose pore space consists of nanotunnels interconnected by nanotube bridges. Such hierarchical nanoporous carbons with mesopores and micropores have shown high specific electric double layer capacitances and high rate capability in an organic electrolyte. We express the anisotropic diffusion coefficient and adsorption coefficient of such materials in terms of the tunnels' properties (pore radius and inter-pore throat width) and their connectivity (spacing between the adjacent tunnels and nanotube-bridge density). Our analysis is applicable for solutes that undergo a non-equilibrium Langmuir adsorption reaction on the surfaces of fluid-filled pores, but other homogeneous and heterogeneous reactions can be handled in a similar fashion. The presented results can be used to guide the design of nanoporous materials with optimal permeability and sorption capacity.

  12. Materials design data for reduced activation martensitic steel type EUROFER

    NASA Astrophysics Data System (ADS)

    Tavassoli, A.-A. F.; Alamo, A.; Bedel, L.; Forest, L.; Gentzbittel, J.-M.; Rensman, J.-W.; Diegele, E.; Lindau, R.; Schirra, M.; Schmitt, R.; Schneider, H. C.; Petersen, C.; Lancha, A.-M.; Fernandez, P.; Filacchioni, G.; Maday, M. F.; Mergia, K.; Boukos, N.; Baluc; Spätig, P.; Alves, E.; Lucon, E.

    2004-08-01

    Materials design limits derived so far from the data generated in Europe for the reduced activation ferritic/martensitic (RAFM) steel type Eurofer are presented. These data address the short-term needs of the ITER Test Blanket Modules and a DEMOnstration fusion reactor. Products tested include plates, bars, tubes, TIG and EB welds, as well as powder consolidated blocks and solid-solid HIP joints. Effects of thermal ageing and low dose neutron irradiation are also included. Results are sorted and screened according to design code requirements before being introduced in reference databases. From the physical properties databases, variations of magnetic properties, modulus of elasticity, density, thermal conductivity, thermal diffusivity, specific heat, mean and instantaneous linear coefficients of thermal expansion versus temperature are derived. From the tensile and creep properties databases design allowable stresses are derived. From the instrumented Charpy impact and fracture toughness databases, ductile to brittle transition temperature, toughness and behavior of materials in different fracture modes are evaluated. From the fatigue database, total strain range versus number of cycles to failure curves are plotted and used to derive fatigue design curves. Cyclic curves are also derived and compared with monotonic hardening curves. Finally, irradiated and aged materials data are compared to ensure that the safety margins incorporated in unirradiated design limits are not exceeded.

  13. Neural-network-biased genetic algorithms for materials design

    NASA Astrophysics Data System (ADS)

    Patra, Tarak; Meenakshisundaram, Venkatesh; Simmons, David

    Machine learning tools have been progressively adopted by the materials science community to accelerate design of materials with targeted properties. However, in the search for new materials exhibiting properties and performance beyond that previously achieved, machine learning approaches are frequently limited by two major shortcomings. First, they are intrinsically interpolative. They are therefore better suited to the optimization of properties within the known range of accessible behavior than to the discovery of new materials with extremal behavior. Second, they require the availability of large datasets, which in some fields are not available and would be prohibitively expensive to produce. Here we describe a new strategy for combining genetic algorithms, neural networks and other machine learning tools, and molecular simulation to discover materials with extremal properties in the absence of pre-existing data. Predictions from progressively constructed machine learning tools are employed to bias the evolution of a genetic algorithm, with fitness evaluations performed via direct molecular dynamics simulation. We survey several initial materials design problems we have addressed with this framework and compare its performance to that of standard genetic algorithm approaches. We acknowledge the W. M. Keck Foundation for support of this work.

  14. Turning statistical physics models into materials design engines

    PubMed Central

    Miskin, Marc Z.; Khaira, Gurdaman; de Pablo, Juan J.; Jaeger, Heinrich M.

    2016-01-01

    Despite the success statistical physics has enjoyed at predicting the properties of materials for given parameters, the inverse problem, identifying which material parameters produce given, desired properties, is only beginning to be addressed. Recently, several methods have emerged across disciplines that draw upon optimization and simulation to create computer programs that tailor material responses to specified behaviors. However, so far the methods developed either involve black-box techniques, in which the optimizer operates without explicit knowledge of the material’s configuration space, or require carefully tuned algorithms with applicability limited to a narrow subclass of materials. Here we introduce a formalism that can generate optimizers automatically by extending statistical mechanics into the realm of design. The strength of this approach lies in its capability to transform statistical models that describe materials into optimizers to tailor them. By comparing against standard black-box optimization methods, we demonstrate how optimizers generated by this formalism can be faster and more effective, while remaining straightforward to implement. The scope of our approach includes possibilities for solving a variety of complex optimization and design problems concerning materials both in and out of equilibrium. PMID:26684770

  15. CubeSat Material Limits for Design for Demise

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.; Jarkey, D. R.

    2014-01-01

    The CubeSat form factor of nano-satellite (a satellite with a mass between one and ten kilograms) has grown in popularity due to their ease of construction and low development and launch costs. In particular, their use as student led payload design projects has increased due to the growing number of launch opportunities. CubeSats are often deployed as secondary or tertiary payloads on most US launch vehicles or they may be deployed from the ISS. The focus of this study will be on CubeSats launched from the ISS. From a space safety standpoint, the development and deployment processes for CubeSats differ significantly from that of most satellites. For large satellites, extensive design reviews and documentation are completed, including assessing requirements associated with re-entry survivability. Typical CubeSat missions selected for ISS deployment have a less rigorous review process that may not evaluate aspects beyond overall design feasibility. CubeSat design teams often do not have the resources to ensure their design is compliant with re-entry risk requirements. A study was conducted to examine methods to easily identify the maximum amount of a given material that can be used in the construction of a CubeSats without posing harm to persons on the ground. The results demonstrate that there is not a general equation or relationship that can be used for all materials; instead a limiting value must be defined for each unique material. In addition, the specific limits found for a number of generic materials that have been previously used as benchmarking materials for re-entry survivability analysis tool comparison will be discussed.

  16. CubeSat Material Limits For Design for Demise

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.; Jarkey, D. R.

    2014-01-01

    The CubeSat form factor of nano-satellite (a satellite with a mass between one and ten kilograms) has grown in popularity due to their ease of construction and low development and launch costs. In particular, their use as student led payload design projects has increased due to the growing number of launch opportunities. CubeSats are often deployed as secondary or tertiary payloads on most US launch vehicles or they may be deployed from the ISS. The focus of this study will be on CubeSats launched from the ISS. From a space safety standpoint, the development and deployment processes for CubeSats differ significantly from that of most satellites. For large satellites, extensive design reviews and documentation are completed, including assessing requirements associated with reentry survivability. Typical CubeSat missions selected for ISS deployment have a less rigorous review process that may not evaluate aspects beyond overall design feasibility. CubeSat design teams often do not have the resources to ensure their design is compliant with reentry risk requirements. A study was conducted to examine methods to easily identify the maximum amount of a given material that can be used in the construction of a CubeSats without posing harm to persons on the ground. The results demonstrate that there is not a general equation or relationship that can be used for all materials; instead a limiting value must be defined for each unique material. In addition, the specific limits found for a number of generic materials that have been previously used as benchmarking materials for reentry survivability analysis tool comparison will be discussed.

  17. The design and modeling of periodic materials with novel properties

    NASA Astrophysics Data System (ADS)

    Berger, Jonathan Bernard

    Cellular materials are ubiquitous in our world being found in natural and engineered systems as structural materials, sound and energy absorbers, heat insulators and more. Stochastic foams made of polymers, metals and even ceramics find wide use due to their novel properties when compared to monolithic materials. Properties of these so called hybrid materials, those that combine materials or materials and space, are derived from the localization of thermomechanical stresses and strains on the mesoscale as a function of cell topology. The effects of localization can only be generalized in stochastic materials arising from their inherent potential complexity, possessing variations in local chemistry, microstructural inhomogeneity and topological variations. Ordered cellular materials on the other hand, such as lattices and honeycombs, make for much easier study, often requiring analysis of only a single unit-cell. Theoretical bounds predict that hybrid materials have the potential to push design envelopes offering lighter stiffer and stronger materials. Hybrid materials can achieve very low and even negative coefficients of thermal expansion (CTE) while retaining a relatively high stiffness -- properties completely unmatched by monolithic materials. In the first chapter of this thesis a two-dimensional lattice is detailed that possess near maximum stiffness, relative to the tightest theoretical bound, and low, zero and even appreciably negative thermal expansion. Its CTE and stiffness are given in closed form as a function of geometric parameters and the material properties. This result is confirmed with finite elements (FE) and experiment. In the second chapter the compressive stiffness of three-dimensional ordered foams, both closed and open cell, are predicted with FE and the results placed in property space in terms of stiffness and density. A novel structure is identified that effectively achieves theoretical bounds for Young's, shear and bulk modulus

  18. The radioactive materials packaging handbook: Design, operations, and maintenance

    SciTech Connect

    Shappert, L.B.; Bowman, S.M.; Arnold, E.D.

    1998-08-01

    As part of its required activities in 1994, the US Department of Energy (DOE) made over 500,000 shipments. Of these shipments, approximately 4% were hazardous, and of these, slightly over 1% (over 6,400 shipments) were radioactive. Because of DOE`s cleanup activities, the total quantities and percentages of radioactive material (RAM) that must be moved from one site to another is expected to increase in the coming years, and these materials are likely to be different than those shipped in the past. Irradiated fuel will certainly be part of the mix as will RAM samples and waste. However, in many cases these materials will be of different shape and size and require a transport packaging having different shielding, thermal, and criticality avoidance characteristics than are currently available. This Handbook provides guidance on the design, testing, certification, and operation of packages for these materials.

  19. Design of electro-active polymer gels as actuator materials

    NASA Astrophysics Data System (ADS)

    Popovic, Suzana

    Smart materials, alternatively called active or adaptive, differ from passive materials in their sensing and activation capability. These materials can sense changes in environment such as: electric field, magnetic field, UV light, pH, temperature. They are capable of responding in numerous ways. Some change their stiffness properties (electro-rheological fluids), other deform (piezos, shape memory alloys, electrostrictive materials) or change optic properties (electrochromic polymers). Polymer gels are one of such materials which can change the shape, volume and even optical properties upon different applied stimuli. Due to their low stiffness property they are capable of having up to 100% of strain in a short time, order of seconds. Their motion resembles the one of biosystems, and they are often seen as possible artificial muscle materials. Despite their delicate nature, appropriate design can make them being used as actuator materials which can form controllable surfaces and mechanical switches. In this study several different groups of polymer gel material were investigated: (a) acrylamide based gels are sensitive to pH and electric field and respond in volume change, (b) polyacrylonitrile (PAN) gel is sensitive to pH and electric field and responds in axial strain and bending, (c) polyvinylalcohol (PVA) gel is sensitive to electric field and responds in axial strain and bending and (d) perfluorinated sulfonic acid membrane, Nafion RTM, is sensitive to electric field and responds in bending. Electro-mechanical and chemo-mechanical behavior of these materials is a function of a variety of phenomena: polymer structure, affinity of polymer to the solvent, charge distribution within material, type of solvent, elasticity of polymer matrix, etc. Modeling of this behavior is a task aimed to identify what is driving mechanism for activation and express it in a quantitative way in terms of deformation of material. In this work behavior of the most promising material as

  20. Design of a Compact Fatigue Tester for Testing Irradiated Materials

    SciTech Connect

    Hartsell, Brian; Campbell, Michael; Fitton, Michael; Hurh, Patrick; Ishida, Taku; Nakadaira, Takeshi

    2015-06-01

    A compact fatigue testing machine that can be easily inserted into a hot cell for characterization of irradiated materials is beneficial to help determine relative fatigue performance differences between new and irradiated material. Hot cell use has been carefully considered by limiting the size and weight of the machine, simplifying sample loading and test setup for operation via master-slave manipulator, and utilizing an efficient design to minimize maintenance. Funded from a US-Japan collaborative effort, the machine has been specifically designed to help characterize titanium material specimens. These specimens are flat cantilevered beams for initial studies, possibly utilizing samples irradiated at other sources of beam. The option to test spherically shaped samples cut from the T2K vacuum window is also available. The machine is able to test a sample to $10^7$ cycles in under a week, with options to count cycles and sense material failure. The design of this machine will be presented along with current status.

  1. Designer Nanocellular Materials for Laser Targets and Other DNT Applications

    SciTech Connect

    Satcher, Jr, J H; Hsiung, L M; Baumann, T F; Maxwell, R S; Chinn, S C; Hodge, A M; Biener, J; Landingham, R L

    2005-01-07

    Overview. This document and the accompanying manuscripts summarize the technical accomplishments of our one-year LDRD-ER effort, a project that has since been incorporated into a larger LDRD-SI for FY05. The objective of this effort was to develop a predictive synthetic capability for the preparation of materials with cellular architectures (sub-micron pore or cell sizes and relative densities less than 10% of full density) not attainable by conventional methods. The ability to reliably prepare these nanocellular materials and control their bulk physical properties (e.g. mechanical strength) would be a considerable advance in the areas of porous materials and its impact would cut across many existing LLNL investments. One significant area related to the Laboratory mission that would benefit is the design of new materials for high energy density physics (HEDP) targets. Current synthetic techniques do not allow for the preparation of foams that meet all of the current and projected compositional and mechanical requirements of these experiments. This project focused on two main types of materials: inorganic sol-gel materials and nanocellular metal foams. The following sections describe the project goals for these two types of materials as well as the progress made towards these goals in FY04. These sections also provide context for the three publications that have been included in this final report.

  2. Gradient-index ophthalmic lens design and polymer material studies

    NASA Astrophysics Data System (ADS)

    Fischer, David Joel

    Unifocal ophthalmic lenses are conventionally designed using homogeneous glass or plastic materials and aspheric surfaces. The desired power and aberration correction are provided by selection of surface shape and refractive index. This thesis studies the design of ophthalmic lenses utilizing gradient-index (GRIN) materials for both the optical power and aberration control. This is done using geometrical optical theory and ray-tracing simulations. Progressive addition lenses (PALS) are vision correction lenses with a continuous change in power used to treat presbyopia. The power variation is typically located in the lower half of the lens. Progressive addition lenses are currently made with aspheric surfaces to achieve the focal power transition and aberration control. These surfaces have at most, mirror symmetry about the vertical axis. The possible design of progressive addition lenses with GRIN materials has not been well studied. This thesis studies PALS and identifies how gradient-index materials can be used to provide both the power progression and aberration control. The optical theory for rotationally symmetric and asymmetric power additions is given. Analytical and numerical methods for calculating the index profile are used, and the results examined using ray-tracing simulations. The theory developed for ophthalmic lenses is applied to the design of GRIN axicon. This is the first GRIN axicon manufactured, and is fabricated using ion-exchanged GRIN glass. Experimental measurements of its performance are compared and found to match theoretical predictions. This demonstrates the generality of the theory developed: it may be applied to non-visual applications, and even to non-imaging applications. Realistic implementation of GRIN technology to ophthalmic application requires the fabrication of large scale refractive index gradients in polymer material systems. The methyl-methacrylate/styrene copolymer system is studied to develop an empirical model of its

  3. Rational material design for ultrafast rechargeable lithium-ion batteries.

    PubMed

    Tang, Yuxin; Zhang, Yanyan; Li, Wenlong; Ma, Bing; Chen, Xiaodong

    2015-10-01

    Rechargeable lithium-ion batteries (LIBs) are important electrochemical energy storage devices for consumer electronics and emerging electrical/hybrid vehicles. However, one of the formidable challenges is to develop ultrafast charging LIBs with the rate capability at least one order of magnitude (>10 C) higher than that of the currently commercialized LIBs. This tutorial review presents the state-of-the-art developments in ultrafast charging LIBs by the rational design of materials. First of all, fundamental electrochemistry and related ionic/electronic conduction theories identify that the rate capability of LIBs is kinetically limited by the sluggish solid-state diffusion process in electrode materials. Then, several aspects of the intrinsic materials, materials engineering and processing, and electrode materials architecture design towards maximizing both ionic and electronic conductivity in the electrode with a short diffusion length are deliberated. Finally, the future trends and perspectives for the ultrafast rechargeable LIBs are discussed. Continuous rapid progress in this area is essential and urgent to endow LIBs with ultrafast charging capability to meet huge demands in the near future. PMID:25857819

  4. Bioinspiration from fish for smart material design and function

    NASA Astrophysics Data System (ADS)

    Lauder, G. V.; Madden, P. G. A.; Tangorra, J. L.; Anderson, E.; Baker, T. V.

    2011-09-01

    Fish are a potentially rich source of inspiration for the design of smart materials. Fish exemplify the use of flexible materials to generate forces during locomotion, and a hallmark of fish functional design is the use of body and fin deformation to power propulsion and maneuvering. As a result of nearly 500 million years of evolutionary experimentation, fish design has a number of interesting features of note to materials engineers. In this paper we first provide a brief general overview of some key features of the mechanical design of fish, and then focus on two key properties of fish: the bilaminar mechanical design of bony fish fin rays that allows active muscular control of curvature, and the role of body flexibility in propulsion. After describing the anatomy of bony fish fin rays, we provide new data on their mechanical properties. Three-point bending tests and measurement of force inputs to and outputs from the fin rays show that these fin rays are effective displacement transducers. Fin rays in different regions of the fin differ considerably in their material properties, and in the curvature produced by displacement of one of the two fin ray halves. The mean modulus for the proximal (basal) region of the fin rays was 1.34 GPa, but this varied from 0.24 to 3.7 GPa for different fin rays. The distal fin region was less stiff, and moduli for the different fin rays measured varied from 0.11 to 0.67 GPa. These data are similar to those for human tendons (modulus around 0.5 GPa). Analysis of propulsion using flexible foils controlled using a robotic flapping device allows investigation of the effect of altering flexural stiffness on swimming speed. Flexible foils with the leading edge moved in a heave show a distinct peak in propulsive performance, while the addition of pitch input produces a broad plateau where the swimming speed is relatively unaffected by the flexural stiffness. Our understanding of the material design of fish and the control of tissue

  5. Photovoltaic module encapsulation design and materials selection. Volume II

    SciTech Connect

    Cuddihy, E.

    1984-06-01

    This is Volume II of Photovoltaic Module Encapsulation Design and Materials Selection: a periodically updated handbook of encapsulation technology, developed with the support of the Flat-Plate Solar Array Project (FSA), managed for the Department of Energy (DOE) by the Jet Propulsion Laboratory. Volume II describes FSA encapsulation technology developed between June 1, 1982, and January 1, 1984. Emphasis during this period shifted from materials development to demonstration of reliability and durability in an outdoor environment; the updated information in this volume reflects the developing technology base related to both reliability and encapsulation process improvements.

  6. Design of Material Strength Test in Lead-Bismuth Flow

    SciTech Connect

    Masatoshi Kondo; Minoru Takahashi; Koji Hata

    2002-07-01

    Liquid lead and lead-bismuth have drawn the attention as one of the candidate coolants of the fast breeder reactors (FBRs), and the accelerator driven transmutation systems (ADSs). In order to use the coolant to the systems, the physical and chemical characteristics of the heavy metals are necessary. This plan has been proposed for the strength test of materials in the liquid metal surroundings. The lead-bismuth circulation loop with the strength test has been designed, and the strength test of candidate materials has been planned. (authors)

  7. Rational Design of Pathogen-Mimicking Amphiphilic Materials as Nanoadjuvants

    NASA Astrophysics Data System (ADS)

    Ulery, Bret D.; Petersen, Latrisha K.; Phanse, Yashdeep; Kong, Chang Sun; Broderick, Scott R.; Kumar, Devender; Ramer-Tait, Amanda E.; Carrillo-Conde, Brenda; Rajan, Krishna; Wannemuehler, Michael J.; Bellaire, Bryan H.; Metzger, Dennis W.; Narasimhan, Balaji

    2011-12-01

    An opportunity exists today for cross-cutting research utilizing advances in materials science, immunology, microbial pathogenesis, and computational analysis to effectively design the next generation of adjuvants and vaccines. This study integrates these advances into a bottom-up approach for the molecular design of nanoadjuvants capable of mimicking the immune response induced by a natural infection but without the toxic side effects. Biodegradable amphiphilic polyanhydrides possess the unique ability to mimic pathogens and pathogen associated molecular patterns with respect to persisting within and activating immune cells, respectively. The molecular properties responsible for the pathogen-mimicking abilities of these materials have been identified. The value of using polyanhydride nanovaccines was demonstrated by the induction of long-lived protection against a lethal challenge of Yersinia pestis following a single administration ten months earlier. This approach has the tantalizing potential to catalyze the development of next generation vaccines against diseases caused by emerging and re-emerging pathogens.

  8. Exascale Co-design for Modeling Materials in Extreme Environments

    SciTech Connect

    Germann, Timothy C.

    2014-07-08

    Computational materials science has provided great insight into the response of materials under extreme conditions that are difficult to probe experimentally. For example, shock-induced plasticity and phase transformation processes in single-crystal and nanocrystalline metals have been widely studied via large-scale molecular dynamics simulations, and many of these predictions are beginning to be tested at advanced 4th generation light sources such as the Advanced Photon Source (APS) and Linac Coherent Light Source (LCLS). I will describe our simulation predictions and their recent verification at LCLS, outstanding challenges in modeling the response of materials to extreme mechanical and radiation environments, and our efforts to tackle these as part of the multi-institutional, multi-disciplinary Exascale Co-design Center for Materials in Extreme Environments (ExMatEx). ExMatEx has initiated an early and deep collaboration between domain (computational materials) scientists, applied mathematicians, computer scientists, and hardware architects, in order to establish the relationships between algorithms, software stacks, and architectures needed to enable exascale-ready materials science application codes within the next decade. We anticipate that we will be able to exploit hierarchical, heterogeneous architectures to achieve more realistic large-scale simulations with adaptive physics refinement, and are using tractable application scale-bridging proxy application testbeds to assess new approaches and requirements. Such current scale-bridging strategies accumulate (or recompute) a distributed response database from fine-scale calculations, in a top-down rather than bottom-up multiscale approach.

  9. Thermo-magnetic materials for use in designing intelligent actuators

    SciTech Connect

    Ohtani, Yoshimutsu; Yoshimura, Fumikatsu; Hatakeyama, Iwao; Ishii, Yoshikazu

    1994-12-31

    The authors present the concept of an intelligent thermal actuator designed by using thermally sensitive magnetic materials. The use of the magnetic transition of FeRh alloy is very effective in increasing the actuator functions. These functions are freedom of direction, tuning temperature, and increasing both sensitivity and power. Two new types of actuator, a remote controlled optical driven thermo-magnetic motor and a temperature sensitive spring-less valve, are proposed and experimental results are shown.

  10. Module Design, Materials, and Packaging Research Team: Activities and Capabilities

    SciTech Connect

    McMahon, T. J.; del Cueto, J.; Glick, S.; Jorgensen, G.; Kempe, M.; Kennedy, C.; Pern, J.; Terwilliger, K

    2005-01-01

    Our team activities are directed at improving PV module reliability by incorporating new, more effective, and less expensive packaging materials and techniques. New and existing materials or designs are evaluated before and during accelerated environmental exposure for the following properties: (1) Adhesion and cohesion: peel strength and lap shear. (2) Electrical conductivity: surface, bulk, interface and transients. (3) Water vapor transmission: solubility and diffusivity. (4) Accelerated weathering: ultraviolet, temperature, and damp heat tests. (5) Module and cell failure diagnostics: infrared imaging, individual cell shunt characterization, coring. (6) Fabrication improvements: SiOxNy barrier coatings and enhanced wet adhesion. (7) Numerical modeling: Moisture ingress/egress, module and cell performance, and cell-to-frame leakage current. (8) Rheological properties of polymer encapsulant and sheeting materials. Specific examples will be described.

  11. Macroscopic shock plasticity of brittle material through designed void patterns

    NASA Astrophysics Data System (ADS)

    Jiang, Tailong; Yu, Yin; He, Hongliang; Li, Yongqiang; Huan, Qiang; Wu, Jiankui

    2016-03-01

    The rapid propagation and coalescence of cracks and catastrophic fractures, which occur often under shock compression, compromise a brittle material's design function and restrict its scope of practical application. The shock plasticity of brittle materials can be improved significantly by introducing and designing its microstructure, which can help reduce or delay failure. We used a lattice-spring model, which can describe elastic deformation and brittle fracture of modeled material accurately, to study the influence of void distributions (random, square, hexagonal, and triangular void patterns) on the macroscopic shock response and the mesoscopic deformation feature of brittle materials. Calculated results indicate that the void patterns dominate two inelastic deformation stages on the Hugoniot stress-strain curves (the collapse deformation stage and the slippage deformation stage). It shows that the strain localization is not strong and that the broken media are closer to a round bulk when the samples exist in random and triangular void patterns. This favors an increase in deformation during the slippage deformation stage. For the samples with square and hexagonal void patterns, the strain localization is strong and the broken media are closer to columnar bulks, which favors an increase in deformation during the collapse deformation stage.

  12. Design of Functional Materials based on Liquid Crystalline Droplets

    PubMed Central

    Miller, Daniel S.; Wang, Xiaoguang; Abbott, Nicholas L.

    2014-01-01

    This brief perspective focuses on recent advances in the design of functional soft materials that are based on confinement of low molecular weight liquid crystals (LCs) within micrometer-sized droplets. While the ordering of LCs within micrometer-sized domains has been explored extensively in polymer-dispersed LC materials, recent studies performed with LC domains with precisely defined size and interfacial chemistry have unmasked observations of confinement-induced ordering of LCs that do not follow previously reported theoretical predictions. These new findings, which are enabled in part by advances in the preparation of LCs encapsulated in polymeric shells, are opening up new opportunities for the design of soft responsive materials based on surface-induced ordering transitions. These materials are also providing new insights into the self-assembly of biomolecular and colloidal species at defects formed by LCs confined to micrometer-sized domains. The studies presented in this perspective serve additionally to highlight gaps in knowledge regarding the ordering of LCs in confined systems. PMID:24882944

  13. Design of Responsive and Active (Soft) Materials Using Liquid Crystals.

    PubMed

    Bukusoglu, Emre; Bedolla Pantoja, Marco; Mushenheim, Peter C; Wang, Xiaoguang; Abbott, Nicholas L

    2016-06-01

    Liquid crystals (LCs) are widely known for their use in liquid crystal displays (LCDs). Indeed, LCDs represent one of the most successful technologies developed to date using a responsive soft material: An electric field is used to induce a change in ordering of the LC and thus a change in optical appearance. Over the past decade, however, research has revealed the fundamental underpinnings of potentially far broader and more pervasive uses of LCs for the design of responsive soft material systems. These systems involve a delicate interplay of the effects of surface-induced ordering, elastic strain of LCs, and formation of topological defects and are characterized by a chemical complexity and diversity of nano- and micrometer-scale geometry that goes well beyond that previously investigated. As a reflection of this evolution, the community investigating LC-based materials now relies heavily on concepts from colloid and interface science. In this context, this review describes recent advances in colloidal and interfacial phenomena involving LCs that are enabling the design of new classes of soft matter that respond to stimuli as broad as light, airborne pollutants, bacterial toxins in water, mechanical interactions with living cells, molecular chirality, and more. Ongoing efforts hint also that the collective properties of LCs (e.g., LC-dispersed colloids) will, over the coming decade, yield exciting new classes of driven or active soft material systems in which organization (and useful properties) emerges during the dissipation of energy. PMID:26979412

  14. Textile materials for the design of wearable antennas: a survey.

    PubMed

    Salvado, Rita; Loss, Caroline; Gonçalves, Ricardo; Pinho, Pedro

    2012-01-01

    In the broad context of Wireless Body Sensor Networks for healthcare and pervasive applications, the design of wearable antennas offers the possibility of ubiquitous monitoring, communication and energy harvesting and storage. Specific requirements for wearable antennas are a planar structure and flexible construction materials. Several properties of the materials influence the behaviour of the antenna. For instance, the bandwidth and the efficiency of a planar microstrip antenna are mainly determined by the permittivity and the thickness of the substrate. The use of textiles in wearable antennas requires the characterization of their properties. Specific electrical conductive textiles are available on the market and have been successfully used. Ordinary textile fabrics have been used as substrates. However, little information can be found on the electromagnetic properties of regular textiles. Therefore this paper is mainly focused on the analysis of the dielectric properties of normal fabrics. In general, textiles present a very low dielectric constant that reduces the surface wave losses and increases the impedance bandwidth of the antenna. However, textile materials are constantly exchanging water molecules with the surroundings, which affects their electromagnetic properties. In addition, textile fabrics are porous, anisotropic and compressible materials whose thickness and density might change with low pressures. Therefore it is important to know how these characteristics influence the behaviour of the antenna in order to minimize unwanted effects. This paper presents a survey of the key points for the design and development of textile antennas, from the choice of the textile materials to the framing of the antenna. An analysis of the textile materials that have been used is also presented. PMID:23202235

  15. Textile Materials for the Design of Wearable Antennas: A Survey

    PubMed Central

    Salvado, Rita; Loss, Caroline; Gonçalves, Ricardo; Pinho, Pedro

    2012-01-01

    In the broad context of Wireless Body Sensor Networks for healthcare and pervasive applications, the design of wearable antennas offers the possibility of ubiquitous monitoring, communication and energy harvesting and storage. Specific requirements for wearable antennas are a planar structure and flexible construction materials. Several properties of the materials influence the behaviour of the antenna. For instance, the bandwidth and the efficiency of a planar microstrip antenna are mainly determined by the permittivity and the thickness of the substrate. The use of textiles in wearable antennas requires the characterization of their properties. Specific electrical conductive textiles are available on the market and have been successfully used. Ordinary textile fabrics have been used as substrates. However, little information can be found on the electromagnetic properties of regular textiles. Therefore this paper is mainly focused on the analysis of the dielectric properties of normal fabrics. In general, textiles present a very low dielectric constant that reduces the surface wave losses and increases the impedance bandwidth of the antenna. However, textile materials are constantly exchanging water molecules with the surroundings, which affects their electromagnetic properties. In addition, textile fabrics are porous, anisotropic and compressible materials whose thickness and density might change with low pressures. Therefore it is important to know how these characteristics influence the behaviour of the antenna in order to minimize unwanted effects. This paper presents a survey of the key points for the design and development of textile antennas, from the choice of the textile materials to the framing of the antenna. An analysis of the textile materials that have been used is also presented. PMID:23202235

  16. Chalcogenide Glass Radiation Sensor; Materials Development, Design and Device Testing

    SciTech Connect

    Mitkova, Maria; Butt, Darryl; Kozicki, Michael; Barnaby, Hugo

    2013-04-30

    studied the effect of x-rays and γ-rays, on thin film chalcogenide glasses and applied them in conjunction with film incorporating a silver source in a new type of radiation sensor for which we have an US patent application [3]. In this report, we give data about our studies regarding our designed radiation sensor along with the testing and performance at various radiation doses. These studies have been preceded by materials characterization research related to the compositional and structural characteristics of the active materials used in the radiation sensor design. During the work on the project, we collected a large volume of material since every experiment was repeated many times to verify the results. We conducted a comprehensive material research, analysis and discussion with the aim to understand the nature of the occurring effects, design different structures to harness these effects, generated models to aid in the understanding the effects, built different device structures and collected data to quantify device performance. These various aspects of our investigation have been detailed in previous quarterly reports. In this report, we present our main results and emphasize on the results pertaining to the core project goals materials development, sensor design and testing and with an emphasis on classifying the appropriate material and design for the optimal application. The report has three main parts: (i) Presentation of the main data; (ii) Bulleted summary of the most important results; (iii) List of the patent, journal publications, conference proceedings and conferences participation, occurring as a result of working on the project.

  17. Designs and Materials for Better Coronagraph Occulting Masks

    NASA Technical Reports Server (NTRS)

    Balasubramanian, Kunjithapatham

    2010-01-01

    New designs, and materials appropriate for such designs, are under investigation in an effort to develop coronagraph occulting masks having broad-band spectral characteristics superior to those currently employed. These designs and materials are applicable to all coronagraphs, both ground-based and spaceborne. This effort also offers potential benefits for the development of other optical masks and filters that are required (1) for precisely tailored spatial transmission profiles, (2) to be characterized by optical-density neutrality and phase neutrality (that is, to be characterized by constant optical density and constant phase over broad wavelength ranges), and/or (3) not to exhibit optical- density-dependent phase shifts. The need for this effort arises for the following reasons: Coronagraph occulting masks are required to impose, on beams of light transmitted through them, extremely precise control of amplitude and phase according to carefully designed transmission profiles. In the original application that gave rise to this effort, the concern has been to develop broad-band occulting masks for NASA s Terrestrial Planet Finder coronagraph. Until now, experimental samples of these masks have been made from high-energy-beam-sensitive (HEBS) glass, which becomes locally dark where irradiated with a high-energy electron beam, the amount of darkening depending on the electron-beam energy and dose. Precise mask profiles have been written on HEBS glass blanks by use of electron beams, and the masks have performed satisfactorily in monochromatic light. However, the optical-density and phase profiles of the HEBS masks vary significantly with wavelength; consequently, the HEBS masks perform unsatisfactorily in broad-band light. The key properties of materials to be used in coronagraph occulting masks are their extinction coefficients, their indices of refraction, and the variations of these parameters with wavelength. The effort thus far has included theoretical

  18. Interfacial properties and design of functional energy materials.

    PubMed

    Sumpter, Bobby G; Liang, Liangbo; Nicolaï, Adrien; Meunier, Vincent

    2014-11-18

    CONSPECTUS: The vital importance of energy to society continues to demand a relentless pursuit of energy responsive materials that can bridge fundamental chemical structures at the molecular level and achieve improved functionality and performance. This demand can potentially be realized by harnessing the power of self-assembly, a spontaneous process where molecules or much larger entities form ordered aggregates as a consequence of predominately noncovalent (weak) interactions. Self-assembly is the key to bottom-up design of molecular devices, because the nearly atomic-level control is very difficult to realize in a top-down, for example, lithographic, approach. However, while function in simple systems such as single crystals can often be evaluated a priori, predicting the function of the great variety of self-assembled molecular architectures is complicated by the lack of understanding and control over nanoscale interactions, mesoscale architectures, and macroscale order. To establish a foundation toward delivering practical solutions, it is critical to develop an understanding of the chemical and physical mechanisms responsible for the self-assembly of molecular and hybrid materials on various support substrates. Typical molecular self-assembly involves noncovalent intermolecular and substrate-molecule interactions. These interactions remain poorly understood, due to the combination of many-body interactions compounded by local or collective influences from the substrate atomic lattice and electronic structure. Progress toward unraveling the underlying physicochemical processes that control the structure and macroscopic physical, chemical, mechanical, electrical, and transport properties of materials increasingly requires tight integration of theory, modeling, and simulation with precision synthesis, advanced experimental characterization, and device measurements. Theory, modeling, and simulation can accelerate the process of materials understanding and design

  19. New approach to design of ceramic/polymer material compounds

    NASA Astrophysics Data System (ADS)

    Todt, A.; Nestler, D.; Trautmann, M.; Wagner, G.

    2016-03-01

    The damage tolerance of carbon fibre-reinforced ceramic-matrix composite materials depends on their porosity and can be rather significant. Complex structures are difficult to produce. The integration of simple geometric structures of ceramic-matrix composite materials in complex polymer-based hybrid structures is a possible approach of realising those structures. These hybrid material compounds, produced in a cost-efficient way, combine the different advantages of the individual components in one hybrid material compound. In addition the individual parts can be designed to fit a specific application and the resulting forces. All these different advantages result in a significant reduction of not only the production costs and the production time, but also opens up new areas of application, such as the large-scale production of wear-resistant and chemically inert, energy dampening components for reactors or in areas of medicine. The low wettability of the ceramic component however is a disadvantage of this approach. During the course of this contribution, different C/C composite materials with a specific porosity were produced, while adjusting the resin/hardening agent-ratio, as well as the processing parameters. After the production, different penetration tests were conducted with a polymer component. The final part of the article is comprised of the microstructural analysis and the explanation of the mechanical relationships.

  20. Materials, design and processing of air encapsulated MEMS packaging

    NASA Astrophysics Data System (ADS)

    Fritz, Nathan T.

    This work uses a three-dimensional air cavity technology to improve the fabrication, and functionality of microelectronics devices, performance of on-board transmission lines, and packaging of micro-electromechanical systems (MEMS). The air cavity process makes use of the decomposition of a patterned sacrificial polymer followed by the diffusion of its by-products through a curing polymer overcoat to obtain the embedded air structure. Applications and research of air cavities have focused on simple designs that concentrate on the size and functionality of the particular device. However, a lack of guidelines for fabrication, materials used, and structural design has led to mechanical stability issues and processing refinements. This work investigates improved air gap cavities for use in MEMS packaging processes, resulting in fewer fabrication flaws and lower cost. The identification of new materials, such as novel photo-definable organic/inorganic hybrid polymers, was studied for increased strength and rigidity due to their glass-like structure. A novel epoxy polyhedral oligomeric silsesquioxane (POSS) material was investigated and characterized for use as a photodefineable, permanent dielectrics with improved mechanical properties. The POSS material improved the air gap fabrication because it served as a high-selectivity etch mask for patterning sacrificial materials as well as a cavity overcoat material with improved rigidity. An investigation of overcoat thickness and decomposition kinetics provided a fundamental understanding of the properties that impart mechanical stability to cavities of different shape and volume. Metallization of the cavities was investigated so as to provide hermetic sealing and improved cavity strength. The improved air cavity, wafer-level packages were tested using resonator-type devices and chip-level lead frame packaging. The air cavity package was molded under traditional lead frame molding pressures and tested for mechanical

  1. System design for safe robotic handling of nuclear materials

    SciTech Connect

    Drotning, W.; Wapman, W.; Fahrenholtz, J.; Kimberly, H.; Kuhlmann, J.

    1996-03-01

    Robotic systems are being developed by the Intelligent Systems and Robotics Center at Sandia National Laboratories to perform automated handling tasks with radioactive nuclear materials. These systems will reduce the occupational radiation exposure to workers by automating operations which are currently performed manually. Because the robotic systems will handle material that is both hazardous and valuable, the safety of the operations is of utmost importance; assurance must be given that personnel will not be harmed and that the materials and environment will be protected. These safety requirements are met by designing safety features into the system using a layered approach. Several levels of mechanical, electrical and software safety prevent unsafe conditions from generating a hazard, and bring the system to a safe state should an unexpected situation arise. The system safety features include the use of industrial robot standards, commercial robot systems, commercial and custom tooling, mechanical safety interlocks, advanced sensor systems, control and configuration checks, and redundant control schemes. The effectiveness of the safety features in satisfying the safety requirements is verified using a Failure Modes and Effects Analysis. This technique can point out areas of weakness in the safety design as well as areas where unnecessary redundancy may reduce the system reliability.

  2. Test model designs for advanced refractory ceramic materials

    NASA Technical Reports Server (NTRS)

    Tran, Huy Kim

    1993-01-01

    The next generation of space vehicles will be subjected to severe aerothermal loads and will require an improved thermal protection system (TPS) and other advanced vehicle components. In order to ensure the satisfactory performance system (TPS) and other advanced vehicle materials and components, testing is to be performed in environments similar to space flight. The design and fabrication of the test models should be fairly simple but still accomplish test objectives. In the Advanced Refractory Ceramic Materials test series, the models and model holders will need to withstand the required heat fluxes of 340 to 817 W/sq cm or surface temperatures in the range of 2700 K to 3000 K. The model holders should provide one dimensional (1-D) heat transfer to the samples and the appropriate flow field without compromising the primary test objectives. The optical properties such as the effective emissivity, catalytic efficiency coefficients, thermal properties, and mass loss measurements are also taken into consideration in the design process. Therefore, it is the intent of this paper to demonstrate the design schemes for different models and model holders that would accommodate these test requirements and ensure the safe operation in a typical arc jet facility.

  3. Design Molecular Recognition Materials for Chiral Sensors, Separtations and Catalytic Materials

    SciTech Connect

    Jia, S.; Nenoff, T.M.; Provencio, P.; Qiu, Y.; Shelnutt, J.A.; Thoma, S.G.; Zhang, J.

    1998-11-01

    The goal is the development of materials that are highly sensitive and selective for chid chemicals and biochemical (such as insecticides, herbicides, proteins, and nerve agents) to be used as sensors, catalysts and separations membranes. Molecular modeling methods are being used to tailor chiral molecular recognition sites with high affinity and selectivity for specified agents. The work focuses on both silicate and non-silicate materials modified with chirally-pure fictional groups for the catalysis or separations of enantiomerically-pure molecules. Surfactant and quaternary amine templating is being used to synthesize porous frameworks, containing mesopores of 30 to 100 angstroms. Computer molecukw modeling methods are being used in the design of these materials, especially in the chid surface- modi~ing agents. Molecular modeling is also being used to predict the catalytic and separations selectivities of the modified mesoporous materials. The ability to design and synthesize tailored asymmetric molecular recognition sites for sensor coatings allows a broader range of chemicals to be sensed with the desired high sensitivity and selectivity. Initial experiments target the selective sensing of small molecule gases and non-toxic model neural compounds. Further efforts will address designing sensors that greatly extend the variety of resolvable chemical species and forming a predictive, model-based method for developing advanced sensors.

  4. Advanced composite structures. [metal matrix composites - structural design criteria for spacecraft construction materials

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A monograph is presented which establishes structural design criteria and recommends practices to ensure the design of sound composite structures, including composite-reinforced metal structures. (It does not discuss design criteria for fiber-glass composites and such advanced composite materials as beryllium wire or sapphire whiskers in a matrix material.) Although the criteria were developed for aircraft applications, they are general enough to be applicable to space vehicles and missiles as well. The monograph covers four broad areas: (1) materials, (2) design, (3) fracture control, and (4) design verification. The materials portion deals with such subjects as material system design, material design levels, and material characterization. The design portion includes panel, shell, and joint design, applied loads, internal loads, design factors, reliability, and maintainability. Fracture control includes such items as stress concentrations, service-life philosophy, and the management plan for control of fracture-related aspects of structural design using composite materials. Design verification discusses ways to prove flightworthiness.

  5. Porous materials with high negative Poisson’s ratios—a mechanism based material design

    NASA Astrophysics Data System (ADS)

    Kim, Kwangwon; Ju, Jaehyung; Kim, Doo-Man

    2013-08-01

    In an effort to tailor functional materials with customized anisotropic properties—stiffness and yield strain, we propose porous materials consisting of flexible mesostructures designed from the deformation of a re-entrant auxetic honeycomb and compliant mechanisms. Using an analogy between compliant mechanisms and a cellular material’s deformation, we can tailor the in-plane properties of mesostructures; low stiffness and high strain in one direction and high stiffness and low strain in the other direction. An analytical model is developed to obtain the effective moduli and yield strains of the porous materials by combining the kinematics of a rigid link mechanism and deformation of flexure hinges. A numerical technique is implemented with the analytical model for the nonlinear constitutive relations of the mesostructures and their strain-dependent Poisson’s ratios. A finite element analysis (FEA) is used to validate the analytical and numerical models. The designed moduli and yield strain of porous materials with an aluminum alloy are 2 GPa and 0.28% in one direction and 0.2 MPa and 28% in the other direction. These porous materials with mesostructures have high negative Poisson’s ratios, {\

  6. Molecular Design of Benzodithiophene-Based Organic Photovoltaic Materials.

    PubMed

    Yao, Huifeng; Ye, Long; Zhang, Hao; Li, Sunsun; Zhang, Shaoqing; Hou, Jianhui

    2016-06-22

    Advances in the design and application of highly efficient conjugated polymers and small molecules over the past years have enabled the rapid progress in the development of organic photovoltaic (OPV) technology as a promising alternative to conventional solar cells. Among the numerous OPV materials, benzodithiophene (BDT)-based polymers and small molecules have come to the fore in achieving outstanding power conversion efficiency (PCE) and breaking 10% efficiency barrier in the single junction OPV devices. Remarkably, the OPV device featured by BDT-based polymer has recently demonstrated an impressive PCE of 11.21%, indicating the great potential of this class of materials in commercial photovoltaic applications. In this review, we offered an overview of the organic photovoltaic materials based on BDT from the aspects of backbones, functional groups, alkyl chains, and device performance, trying to provide a guideline about the structure-performance relationship. We believe more exciting BDT-based photovoltaic materials and devices will be developed in the near future. PMID:27251307

  7. Testing and design life analysis of polyurea liner materials

    NASA Astrophysics Data System (ADS)

    Ghasemi Motlagh, Siavash

    Certainly, water pipes, as part of an underground infrastructure system, play a key role in maintaining quality of life, health, and wellbeing of human kind. As these potable water pipes reach the end of their useful life, they create high maintenance costs, loss of flow capacity, decreased water quality, and increased dissatisfaction. There are several different pipeline renewal techniques available for different applications, among which linings are most commonly used for the renewal of water pipes. Polyurea is a lining material applied to the interior surface of the deteriorated host pipe using spray-on technique. It is applied to structurally enhance the host pipe and provide a barrier coating against further corrosion or deterioration. The purpose of this study was to establish a relationship between stress, strain and time. The results obtained from these tests were used in predicting the strength of the polyurea material during its planned 50-year design life. In addition to this, based on the 10,000 hours experimental data, curve fitting and Findley power law models were employed to predict long-term behavior of the material. Experimental results indicated that the tested polyurea material offers a good balance of strength and stiffness and can be utilized in structural enhancement applications of potable water pipes.

  8. Designed amyloid fibers as materials for selective carbon dioxide capture

    PubMed Central

    Li, Dan; Furukawa, Hiroyasu; Deng, Hexiang; Liu, Cong; Yaghi, Omar M.; Eisenberg, David S.

    2014-01-01

    New materials capable of binding carbon dioxide are essential for addressing climate change. Here, we demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide via carbamate formation. Thermodynamic and kinetic capture-and-release tests show the carbamate formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence of water, in both a natural amyloid and designed amyloids having increased carbon dioxide capacity. Heating to 100 °C regenerates the material. These results demonstrate the potential of amyloid fibers for environmental carbon dioxide capture. PMID:24367077

  9. Design of materials configurations for enhanced phononic and electronic properties

    NASA Astrophysics Data System (ADS)

    Daraio, Chiara

    The discovery of novel nonlinear dynamic and electronic phenomena is presented for the specific cases of granular materials and carbon nanotubes. This research was conducted for designing and constructing optimized macro-, micro- and nano-scale structural configurations of materials, and for studying their phononic and electronic behavior. Variation of composite arrangements of granular elements with different elastic properties in a linear chain-of-sphere, Y-junction or 3-D configurations led to a variety of novel phononic phenomena and interesting physical properties, which can be potentially useful for security, communications, mechanical and biomedical engineering applications. Mechanical and electronic properties of carbon nanotubes with different atomic arrangements and microstructures were also investigated. Electronic properties of Y-junction configured carbon nanotubes exhibit an exciting transistor switch behavior which is not seen in linear configuration nanotubes. Strongly nonlinear materials were designed and fabricated using novel and innovative concepts. Due to their unique strongly nonlinear and anisotropic nature, novel wave phenomena have been discovered. Specifically, violations of Snell's law were detected and a new mechanism of wave interaction with interfaces between NTPCs (Nonlinear Tunable Phononic Crystals) was established. Polymer-based systems were tested for the first time, and the tunability of the solitary waves speed was demonstrated. New materials with transformed signal propagation speed in the manageable range of 10-100 m/s and signal amplitude typical for audible speech have been developed. The enhancing of the mitigation of solitary and shock waves in 1-D chains were demonstrated and a new protective medium was designed for practical applications. 1-D, 2-D and 3-D strongly nonlinear system have been investigated providing a broad impact on the whole area of strongly nonlinear wave dynamics and creating experimental basis for new

  10. Computational materials design for bulk heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Lin, Xi; Shin, Yongwoo

    2013-03-01

    The adapted Su-Schrieffer-Heeger Hamiltonian is further developed in this work to predict the optical bandgaps of more than 200 different π-conjugated systems. Insights on the structure-property relationship of these π-conjugated systems lead to guiding rules for new photovoltaic materials design. A copolymer of parallel and perpendicular benzodithiophenes, differing only in sulfur atom locations, is proposed as a candidate to achieve the optimal 1.2 eV donor optical gap for organic photovoltaics. The charge transfer mechanisms and the exciton and charge carrier mobilities are computed and compared for various bulk-heterojunction structures to improve the overall power convention efficiency.

  11. Designing thin film materials — Ternary borides from first principles

    PubMed Central

    Euchner, H.; Mayrhofer, P.H.

    2015-01-01

    Exploiting the mechanisms responsible for the exceptional properties of aluminum based nitride coatings, we apply ab initio calculations to develop a recipe for designing functional thin film materials based on ternary diborides. The combination of binary diborides, preferring different structure types, results in supersaturated metastable ternary systems with potential for phase transformation induced effects. For the exemplary cases of MxW1 − xB2 (with M = Al, Ti, V) we show by detailed ab initio calculations that the respective ternary solid solutions are likely to be experimentally accessible by modern depositions techniques. PMID:26082562

  12. ATRP in the design of functional materials for biomedical applications

    PubMed Central

    Siegwart, Daniel J.; Oh, Jung Kwon; Matyjaszewski, Krzysztof

    2013-01-01

    Atom Transfer Radical Polymerization (ATRP) is an effective technique for the design and preparation of multifunctional, nanostructured materials for a variety of applications in biology and medicine. ATRP enables precise control over macromolecular structure, order, and functionality, which are important considerations for emerging biomedical designs. This article reviews recent advances in the preparation of polymer-based nanomaterials using ATRP, including polymer bioconjugates, block copolymer-based drug delivery systems, cross-linked microgels/nanogels, diagnostic and imaging platforms, tissue engineering hydrogels, and degradable polymers. It is envisioned that precise engineering at the molecular level will translate to tailored macroscopic physical properties, thus enabling control of the key elements for realized biomedical applications. PMID:23525884

  13. Taguchi method of experimental design in materials education

    NASA Technical Reports Server (NTRS)

    Weiser, Martin W.

    1993-01-01

    Some of the advantages and disadvantages of the Taguchi Method of experimental design as applied to Materials Science will be discussed. This is a fractional factorial method that employs the minimum number of experimental trials for the information obtained. The analysis is also very simple to use and teach, which is quite advantageous in the classroom. In addition, the Taguchi loss function can be easily incorporated to emphasize that improvements in reproducibility are often at least as important as optimization of the response. The disadvantages of the Taguchi Method include the fact that factor interactions are normally not accounted for, there are zero degrees of freedom if all of the possible factors are used, and randomization is normally not used to prevent environmental biasing. In spite of these disadvantages it is felt that the Taguchi Method is extremely useful for both teaching experimental design and as a research tool, as will be shown with a number of brief examples.

  14. Molecular design of aminopolynitroazole-based high-energy materials.

    PubMed

    Ghule, Vikas D; Srinivas, Dharavath; Sarangapani, Radhakrishnan; Jadhav, Pandurang M; Tewari, Surya P

    2012-07-01

    The density functional theory (DFT) was employed to calculate the energetic properties of several aminopolynitroazoles. The calculations were performed to study the effect of amino and nitro substituents on the heats of formation, densities, detonation performances, thermal stabilities, and sensitivity characteristics of azoles. DFT-B3LYP, DFT-B3PW91, and MP2 methods utilizing the basis sets 6-31 G* and 6-311 G (2df, 3p) were adopted to predict HOFs via designed isodesmic reactions. All of the designed aminopolynitroazoles had heats of formation of >220 kJ mol(-1). The crystal densities of the aminopolynitroazoles were predicted with the cvff force field. All of the energetic azoles had densities of >1.83 g/cm(3). The detonation velocities and pressures were evaluated using the Kamlet-Jacobs equations, utilizing the predicted densities and heats of formation. It was found that aminopolynitroazoles have a detonation velocity of about 9.1 km/s and detonation pressure of 36 GPa. The bond dissociation energies for the C-NO(2) and N-NO(2) bonds were analyzed to investigate the stabilities of the designed molecules. The charge on the nitro group was used to assess impact sensitivity in the present study. The results obtained imply that the designed molecules are stable and are expected to be candidates for high-energy materials (HEMs). PMID:22160794

  15. Hybrid materials science: a promised land for the integrative design of multifunctional materials.

    PubMed

    Nicole, Lionel; Laberty-Robert, Christel; Rozes, Laurence; Sanchez, Clément

    2014-06-21

    For more than 5000 years, organic-inorganic composite materials created by men via skill and serendipity have been part of human culture and customs. The concept of "hybrid organic-inorganic" nanocomposites exploded in the second half of the 20th century with the expansion of the so-called "chimie douce" which led to many collaborations between a large set of chemists, physicists and biologists. Consequently, the scientific melting pot of these very different scientific communities created a new pluridisciplinary school of thought. Today, the tremendous effort of basic research performed in the last twenty years allows tailor-made multifunctional hybrid materials with perfect control over composition, structure and shape. Some of these hybrid materials have already entered the industrial market. Many tailor-made multiscale hybrids are increasingly impacting numerous fields of applications: optics, catalysis, energy, environment, nanomedicine, etc. In the present feature article, we emphasize several fundamental and applied aspects of the hybrid materials field: bioreplication, mesostructured thin films, Lego-like chemistry designed hybrid nanocomposites, and advanced hybrid materials for energy. Finally, a few commercial applications of hybrid materials will be presented. PMID:24866174

  16. Hybrid materials science: a promised land for the integrative design of multifunctional materials

    NASA Astrophysics Data System (ADS)

    Nicole, Lionel; Laberty-Robert, Christel; Rozes, Laurence; Sanchez, Clément

    2014-05-01

    For more than 5000 years, organic-inorganic composite materials created by men via skill and serendipity have been part of human culture and customs. The concept of ``hybrid organic-inorganic'' nanocomposites exploded in the second half of the 20th century with the expansion of the so-called ``chimie douce'' which led to many collaborations between a large set of chemists, physicists and biologists. Consequently, the scientific melting pot of these very different scientific communities created a new pluridisciplinary school of thought. Today, the tremendous effort of basic research performed in the last twenty years allows tailor-made multifunctional hybrid materials with perfect control over composition, structure and shape. Some of these hybrid materials have already entered the industrial market. Many tailor-made multiscale hybrids are increasingly impacting numerous fields of applications: optics, catalysis, energy, environment, nanomedicine, etc. In the present feature article, we emphasize several fundamental and applied aspects of the hybrid materials field: bioreplication, mesostructured thin films, Lego-like chemistry designed hybrid nanocomposites, and advanced hybrid materials for energy. Finally, a few commercial applications of hybrid materials will be presented.

  17. Advances in design and modeling of porous materials

    NASA Astrophysics Data System (ADS)

    Ayral, André; Calas-Etienne, Sylvie; Coasne, Benoit; Deratani, André; Evstratov, Alexis; Galarneau, Anne; Grande, Daniel; Hureau, Matthieu; Jobic, Hervé; Morlay, Catherine; Parmentier, Julien; Prelot, Bénédicte; Rossignol, Sylvie; Simon-Masseron, Angélique; Thibault-Starzyk, Frédéric

    2015-07-01

    This special issue of the European Physical Journal Special Topics is dedicated to selected papers from the symposium "High surface area porous and granular materials" organized in the frame of the conference "Matériaux 2014", held on November 24-28, 2014 in Montpellier, France. Porous materials and granular materials gather a wide variety of heterogeneous, isotropic or anisotropic media made of inorganic, organic or hybrid solid skeletons, with open or closed porosity, and pore sizes ranging from the centimeter scale to the sub-nanometer scale. Their technological and industrial applications cover numerous areas from building and civil engineering to microelectronics, including also metallurgy, chemistry, health, waste water and gas effluent treatment. Many emerging processes related to environmental protection and sustainable development also rely on this class of materials. Their functional properties are related to specific transfer mechanisms (matter, heat, radiation, electrical charge), to pore surface chemistry (exchange, adsorption, heterogeneous catalysis) and to retention inside confined volumes (storage, separation, exchange, controlled release). The development of innovative synthesis, shaping, characterization and modeling approaches enables the design of advanced materials with enhanced functional performance. The papers collected in this special issue offer a good overview of the state-of-the-art and science of these complex media. We would like to thank all the speakers and participants for their contribution to the success of the symposium. We also express our gratitude to the organization committee of "Matériaux 2014". We finally thank the reviewers and the staff of the European Physical Journal Special Topics who made the publication of this special issue possible.

  18. From molecular design and materials construction to organic nanophotonic devices.

    PubMed

    Zhang, Chuang; Yan, Yongli; Zhao, Yong Sheng; Yao, Jiannian

    2014-12-16

    CONSPECTUS: Nanophotonics has recently received broad research interest, since it may provide an alternative opportunity to overcome the fundamental limitations in electronic circuits. Diverse optical materials down to the wavelength scale are required to develop nanophotonic devices, including functional components for light emission, transmission, and detection. During the past decade, the chemists have made their own contributions to this interdisciplinary field, especially from the controlled fabrication of nanophotonic molecules and materials. In this context, organic micro- or nanocrystals have been developed as a very promising kind of building block in the construction of novel units for integrated nanophotonics, mainly due to the great versatility in organic molecular structures and their flexibility for the subsequent processing. Following the pioneering works on organic nanolasers and optical waveguides, the organic nanophotonic materials and devices have attracted increasing interest and developed rapidly during the past few years. In this Account, we review our research on the photonic performance of molecular micro- or nanostructures and the latest breakthroughs toward organic nanophotonic devices. Overall, the versatile features of organic materials are highlighted, because they brings tunable optical properties based on molecular design, size-dependent light confinement in low-dimensional structures, and various device geometries for nanophotonic integration. The molecular diversity enables abundant optical transitions in conjugated π-electron systems, and thus brings specific photonic functions into molecular aggregates. The morphology of these micro- or nanostructures can be further controlled based on the weak intermolecular interactions during molecular assembly process, making the aggregates show photon confinement or light guiding properties as nanophotonic materials. By adoption of some active processes in the composite of two or more

  19. Materials Design for Joinable, High Performance Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Glamm, Ryan James

    An aluminum alloy compatible with friction stir welding is designed for automotive and aerospace structural applications. Current weldable automotive aluminum alloys do not possess the necessary strength to meet safety standards and therefore are not able to replace steel in the automotive body. Significant weight savings could be achieved if steel components are replaced with aluminum. Current aerospace alloys are not weldable, requiring machining of large pieces that are then riveted together. If an aerospace alloy could be friction stir welded, smaller pieces could be welded, reducing material waste. Using a systems approach for materials design, property goals are set from performance objectives. From previous research and computational predictions, a structure is designed for a prototype alloy containing dynamic precipitates to readily dissolve and re-precipitate and high stability precipitates to resist dissolution and coarsening in the weld region. It is found that a Ag modified Al-3.9Mg-0.04Cu (at. %) alloy enhanced the rate and magnitude of hardening during ageing, both beneficial effects for dynamic precipitation. In the same alloy, ageing at 350°C results in hardening from Al 3(Sc,Zr) precipitates. Efforts to effectively precipitate both populations simultaneously are unsuccessful. The Al3(Sc,Zr) precipitation hardened prototype is friction stir processed and no weak zones are found in the weld hardness profile. An aerospace alloy design is proposed, utilizing the dual precipitate structure shown in the prototype. The automotive alloy is designed using a basic strength model with parameters determined from the initial prototype alloy analysis. After ageing to different conditions, the alloy is put through a simulated heat affected zone thermal cycle with a computer controlled induction heater. The aged samples lose hardness from the weld cycle but recover hardness from a post weld heat treatment. Atom probe tomography and transmission electron

  20. Designing Meaningful Density Functional Theory Calculations in Materials Science

    NASA Astrophysics Data System (ADS)

    Mattsson, A. E.

    2005-07-01

    Density functional theory (DFT) methods for calculating the quantum mechanical ground states of condensed matter systems are now a common and significant component of materials research. These methods are also increasingly used in Equation of State work, in particular in the warm dense matter regime. The growing importance of DFT reflects the development of sufficiently accurate functionals, efficient algorithms, and continuing improvements in computing capabilities. As the materials problems to which DFT is applied have become large and complex, so have the sets of calculations necessary to investigate a given problem. Highly versatile, powerful codes exist to serve the practitioner, but designing useful simulations is a complicated task, involving intricate manipulation of many variables, with many pitfalls for the unwary and the inexperienced. We give an overview of DFT and discuss several of the most important issues that go into designing a meaningful DFT calculation. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  1. Failure modes and materials design for biomechanical layer structures

    NASA Astrophysics Data System (ADS)

    Deng, Yan

    ) and strength (400--1400MPa): Y-TZP zirconia, InCeram alumina and Empress II glass-ceramic. Explicit relations for the critical loads P to produce these different damage modes in bilayer and trilayer structures are developed in terms of basic material properties (modulus E, strength, hardness H and toughness T) and geometrical variables (thickness d and contact sphere radius r). These experimentally validated relations are used to design of optimal material combinations for improved fracture resistance and to predict mechanical performance of current dental materials.

  2. Computational design of surfaces, nanostructures and optoelectronic materials

    NASA Astrophysics Data System (ADS)

    Choudhary, Kamal

    Properties of engineering materials are generally influenced by defects such as point defects (vacancies, interstitials, substitutional defects), line defects (dislocations), planar defects (grain boundaries, free surfaces/nanostructures, interfaces, stacking faults) and volume defects (voids). Classical physics based molecular dynamics and quantum physics based density functional theory can be useful in designing materials with controlled defect properties. In this thesis, empirical potential based molecular dynamics was used to study the surface modification of polymers due to energetic polyatomic ion, thermodynamics and mechanics of metal-ceramic interfaces and nanostructures, while density functional theory was used to screen substituents in optoelectronic materials. Firstly, polyatomic ion-beams were deposited on polymer surfaces and the resulting chemical modifications of the surface were examined. In particular, S, SC and SH were deposited on amorphous polystyrene (PS), and C2H, CH3, and C3H5 were deposited on amorphous poly (methyl methacrylate) (PMMA) using molecular dynamics simulations with classical reactive empirical many-body (REBO) potentials. The objective of this work was to elucidate the mechanisms by which the polymer surface modification took place. The results of the work could be used in tailoring the incident energy and/or constituents of ion beam for obtaining a particular chemistry inside the polymer surface. Secondly, a new Al-O-N empirical potential was developed within the charge optimized many body (COMB) formalism. This potential was then used to examine the thermodynamic stability of interfaces and mechanical properties of nanostructures composed of aluminum, its oxide and its nitride. The potentials were tested for these materials based on surface energies, defect energies, bulk phase stability, the mechanical properties of the most stable bulk phase, its phonon properties as well as with a genetic algorithm based evolution theory of

  3. Harvesting bioenergy with rationally designed complex functional materials

    NASA Astrophysics Data System (ADS)

    Kuang, Liangju

    A key challenge in renewable energy is to capture, convert and store solar power with earth-abundant materials and environmentally benign technologies. The goal of this thesis is to develop rationally designed complex functional materials for bio-renewable energy applications. On one hand, photoconversion membrane proteins (MPs) are nature's nanoengineering feats for renewable energy management. Harnessing their functions in synthetic systems could help understand, predict, and ultimately control matter and energy at the nanoscale. This is particularly enticing in the post-genome era as recombinant or cell-free expression of many MPs with high yields becomes possible. However, the labile nature of lipid bilayers renders them unsuitable for use in a broad range of engineered systems. A knowledge gap exists about how to design robust synthetic nanomembranes as lipid-bilayer-mimics to support MP functions and how to direct hierarchical MP reconstitution into those membranes to form 2-D or 3-D ordered proteomembrane arrays. Our studies on proteorhodopsin (PR) and bacterial reaction center (BRC), the two light-harvesting MPs, reveal that a charge-interaction-directed reconstitution (CIDR) mechanism induces spontaneous reconstitution of detergent-solubilized MPs into various amphiphilic block copolymer membranes, many of which have far superior stability than lipid bilayers. Our preliminary data also suggest MPs are not enslaved by the biological membranes they derive from; rather, the chemically nonspecific material properties of MP-supporting membranes may act as allosteric regulators. Versatile chemical designs are possible to modulate the conformational energetics of MPs, hence their transport performance in synthetic systems. On the other hand, microalgae are widely regarded as a sustainable feedstock for biofuel production. Microalgae-derived biofuels have not been commercialized yet because current technologies for microalgae dewatering add a huge cost to the

  4. Designing functionally graded materials with superior load-bearing properties

    PubMed Central

    Zhang, Yu; Sun, Ming-jie; Zhang, Denzil

    2011-01-01

    Ceramic prostheses often fail from fracture and wear. We hypothesize that these failures may be substantially mitigated by an appropriate grading of elastic modulus at the ceramic surface. In this study, we elucidate the effect of elastic modulus profile on the flexural damage resistance of functionally graded materials (FGMs), providing theoretical guidlines for designing FGM with superior load-bearing property. The Young's modulus of the graded structure is assumed to vary in a power-law relation with a scaling exponent n; this is in accordance with experimental observations from our laboratory and elsewhere. Based on the theory for bending of graded beams, we examine the effect of n value and bulk-to-surface modulus ratio (Eb/Es) on stress distribution through the graded layer. Theory predicts that a low exponent (0.15 < n < 0.5), coupled with a relatively small modulus ratio (3 < Eb/Es < 6), is most desirable for reducing the maximum stress and transferring it into the interior, while keeping the surface stress low. Experimentally, we demonstrate that elastically graded materials with various n values and Eb/Es ratios can be fabricated by infiltrating alumina and zirconia with a low-modulus glass. Flexural tests show that graded alumina and zirconia with suitable values of these parameters exhibit superior load-bearing capacity, 20% to 50% higher than their homogeneous counterparts. Improving load-bearing capacity of ceramic materials could have broad impacts on biomedical, civil, structural, and an array of other engineering applications. PMID:22178651

  5. Optimal Design of Honeycomb Material Used to Mitigate Head Impact

    PubMed Central

    Caccese, Vincent; Ferguson, James R.; Edgecomb, Michael

    2013-01-01

    This paper presents a study of the impact resistance of honeycomb structure with the purpose to mitigate impact forces. The objective is to aid in the choice of optimal parameters to minimize the thickness of the honeycomb structure while providing adequate protection to prevent injury due to head impact. Studies are presented using explicit finite element analysis representing the case of an unprotected drop of a rigid impactor onto a simulated floor consisting of vinyl composition tile and concrete. Analysis of honeycomb material to reduce resulting accelerations is also presented where parameters such as honeycomb material modulus, wall thickness, cell geometry and structure depth are compared to the unprotected case. A simplified analysis technique using a genetic algorithm is presented to demonstrate the use of this method to select a minimum honeycomb depth to achieve a desired acceleration level at a given level of input energy. It is important to select a minimum material depth in that smaller dimensions lead toward more aesthetic design that increase the likelihood of that the device is used. PMID:23976812

  6. Materials for Consideration in Standardized Canister Design Activities.

    SciTech Connect

    Bryan, Charles R.; Ilgen, Anastasia Gennadyevna; Enos, David George; Teich-McGoldrick, Stephanie; Hardin, Ernest

    2014-10-01

    This document identifies materials and material mitigation processes that might be used in new designs for standardized canisters for storage, transportation, and disposal of spent nuclear fuel. It also addresses potential corrosion issues with existing dual-purpose canisters (DPCs) that could be addressed in new canister designs. The major potential corrosion risk during storage is stress corrosion cracking of the weld regions on the 304 SS/316 SS canister shell due to deliquescence of chloride salts on the surface. Two approaches are proposed to alleviate this potential risk. First, the existing canister materials (304 and 316 SS) could be used, but the welds mitigated to relieve residual stresses and/or sensitization. Alternatively, more corrosion-resistant steels such as super-austenitic or duplex stainless steels, could be used. Experimental testing is needed to verify that these alternatives would successfully reduce the risk of stress corrosion cracking during fuel storage. For disposal in a geologic repository, the canister will be enclosed in a corrosion-resistant or corrosion-allowance overpack that will provide barrier capability and mechanical strength. The canister shell will no longer have a barrier function and its containment integrity can be ignored. The basket and neutron absorbers within the canister have the important role of limiting the possibility of post-closure criticality. The time period for corrosion is much longer in the post-closure period, and one major unanswered question is whether the basket materials will corrode slowly enough to maintain structural integrity for at least 10,000 years. Whereas there is extensive literature on stainless steels, this evaluation recommends testing of 304 and 316 SS, and more corrosion-resistant steels such as super-austenitic, duplex, and super-duplex stainless steels, at repository-relevant physical and chemical conditions. Both general and localized corrosion testing methods would be used to

  7. Evaluation and design considerations of woven composite flywheel materials constructions

    SciTech Connect

    Sapowith, A.D.; Handy, W.E.; Gurson, A.L.; Lerner, G.R.

    1981-06-15

    Work performed from November 1979 to June 1981 on projects for evaluating the specific energy density capability of bidirectional woven flywheel materials and for developing design approaches for the optimization of those materials is reported. After demonstrating the basic geometry needed to construct a constant stress composite flywheel, a method of construction that can integrate radial and hoop fibers, control the relative stiffness in these two principal directions, and offer low cost in production is explained. Such a construction can be accomplished by weaving the radial fibers with the hoop fibers to form a cloth with a circular or spiral configuration. In this design, the warp fibers become the hoops and the pick fibers become the radials. The varying of radial stiffness is controlled by the choice of the pick pattern. In order to evaluate the circular weave, 0.2-in.-thick discs of approximately 20 in.-dia. were molded using S-glass weave and an epoxy matrix. Tensile specimens cut from the discs in both the radial and hoop directions were tested to failure. Further analyses and tests were performed to determine the optimum weave arrangement and the percent of fiber volume needed to optimize the specific material strength. These analyses show that there is a relatively wide range of pick to warp ratios which achieve optimum specific energy densities and that this range includes ratios that are relatively simple to fabricate. The tensile test data show that specific strengths of the fiberglass circular weave approximate 2.5 x 10/sup 6/ in. which results in energy densities at burst of 35 to 40 W-h/lb. A percent of active composite encompassed by the OD for the composite of 78% has been demonstrated. Fiberglass data suggest that the circular weave flywheel can operate over a life cycle equivalent to 10/sup 6/ deep cycles at the energy density level of 15 W-h/lb. (LCL)

  8. Process design of press hardening with gradient material property influence

    SciTech Connect

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-05-04

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  9. Process design of press hardening with gradient material property influence

    NASA Astrophysics Data System (ADS)

    Neugebauer, R.; Schieck, F.; Rautenstrauch, A.

    2011-05-01

    Press hardening is currently used in the production of automotive structures that require very high strength and controlled deformation during crash tests. Press hardening can achieve significant reductions of sheet thickness at constant strength and is therefore a promising technology for the production of lightweight and energy-efficient automobiles. The manganese-boron steel 22MnB5 have been implemented in sheet press hardening owing to their excellent hot formability, high hardenability, and good temperability even at low cooling rates. However, press-hardened components have shown poor ductility and cracking at relatively small strains. A possible solution to this problem is a selective increase of steel sheet ductility by press hardening process design in areas where the component is required to deform plastically during crash tests. To this end, process designers require information about microstructure and mechanical properties as a function of the wide spectrum of cooling rates and sequences and austenitizing treatment conditions that can be encountered in production environments. In the present work, a Continuous Cooling Transformation (CCT) diagram with corresponding material properties of sheet steel 22MnB5 was determined for a wide spectrum of cooling rates. Heating and cooling programs were conducted in a quenching dilatometer. Motivated by the importance of residual elasticity in crash test performance, this property was measured using a micro-bending test and the results were integrated into the CCT diagrams to complement the hardness testing results. This information is essential for the process design of press hardening of sheet components with gradient material properties.

  10. A new design concept for multifunctional fasteners using smart materials

    NASA Astrophysics Data System (ADS)

    Yoon, Hwan-Sik

    2009-03-01

    In this paper, a new design concept for multifunctional fasteners using smart materials is presented. The proposed piezoelectric devices, named 'smart fasteners,' can be fabricated by modifying the design of ordinary fasteners such that they have a piezoelectric element and a control unit embedded in their body. These smart fasteners can not only clamp structural members like ordinary fasteners but also measure the response of the structure and generate forces to enhance the dynamic performance of the structure. Due to their fastener-type design, they are more convenient to install onto or remove from structures compared to conventional piezoceramic patch actuators for which a bonding epoxy layer needs to be applied. In order to demonstrate their applicability in active vibration controls, a simulation study was conducted on a fixed-fixed beam structure. Since the control force is applied at the boundary of the structure where the smart fasteners are attached, a new control algorithm called Active Boundary Control (ABC) was developed using the Lyapunov's direct method. The simulation results show that smart fasteners can be used to suppress vibration of the beam by applying the Lyapunov-based Active Boundary Control algorithm.

  11. Design of Functional Materials with Hydrogen-Bonded Host Frameworks

    NASA Astrophysics Data System (ADS)

    Soegiarto, Airon Cosanova

    The properties of molecular crystals are governed by the attributes of their molecular constituents and their solid-state arrangements, making control of crystal packing paramount when designing new materials with targeted functions. One effective strategy involves the use of robust host frameworks that encapsulate functional guests in molecular-scale cavities with tailored shapes, sizes, and chemical environments that enable systematic regulation of solid state properties. This approach promises to simplify the synthesis of molecular materials by decoupling the design of structure, provided by the host framework, from function, introduced by the guests. This thesis has reported a series of crystalline, structurally robust hosts based on guanidinium cations (G = (C(NH2) 3 +) and the sulfonate moieties of organodisulfonate anions (DS; S = -O3S-R-SO3 -). The host framework is based on layers of 2-D GS sheet, which are interconnected by the organic residues (pillars) of the disulfonates, thereby producing a lamellar architecture with inclusion cavities, occupied by guest molecules, between the sheets. Notably, the GDS inclusion compounds exhibit numerous architectures such as bilayer, simple brick, and zigzag brick -- each endowed with uniquely sized and shaped cavities, suggesting that the aggregation motifs of the included guests can be controlled within the host lattice. Furthermore, the selectivity toward different architectures is governed by the relative size of the pillars and guests, allowing the construction of a "structural phase diagram" which can be used to predict the solid-state architecture of untested host-guest combination. Consequently, a variety of functional molecules have been included in order to exploit these features. Chapter 3 reports the inclusion of polyconjugated molecules within the GDS hosts, generating various guest aggregation motifs -- edge-to-edge to face-to-edge to end-to-end. The effects of the various host and/or guest aggregation

  12. Design of nanostructured materials from block copolymer self-assembly

    NASA Astrophysics Data System (ADS)

    Leolukman, Melvina

    We present two classes of nanostructured materials by combining the self assembly of block copolymer (BCP) with suitable small molecule chemistry, which are applicable to organic electro-optics (EO) and as etch-resistant masks for nanofabrication. The underlying principles of designing the specific interactions between BCP host and guest molecules, driving the self-assembly in bulk and thin film, and dictating domain orientation are concepts common to both of these areas. Nanostructured EO materials were created by selectively encapsulating EO chromophores by hydrogen-bonding to the pyridine groups of a linear-diblock copolymer (linear-diBCP) namely polystyrene-block-poly(4-vinyl pyridine) [PS-b-P4VP], or a linear-dendritic-BCP. With the linear-diBCP host, we discovered that poled order in confined domains depends on domain shape, chromophore concentration within the domain, and thermal history. The linear-dendritic-BCP is an excellent host as it efficiently disperses the chromophores into small domains (5-10nm), and keeps the chromophores apart within the domains due to the dendritic architecture. These morphological effects translated into excellent film processability, increased chromophore loading, and two-fold enhancements in the EO coefficient (r 33) when compared to a corresponding homopolymer system. A new class of organic-inorganic nanostructured materials based on polyhedral oligomeric silsesquioxane (POSS) was synthesized as a passive template for pattern transfer. We developed a living anionic polymerization route for methacrylate-functionalized POSS and synthesized two kinds of BCPs, namely PS-b-PMAPOSS and PMMA-b-PMAPOSS. The anionic route allows high degree of polymerization, narrow polydispersity, and tunable POSS block length. These lead to well defined spherical, cylindrical, and lamellar morphologies, as well as formation of hierarchical structures upon thermal annealing. Both POSS-containing BCPs were assembled in thin film and converted to hard

  13. Harnessing the Big Data Paradigm for ICME: Shifting from Materials Selection to Materials Enabled Design

    NASA Astrophysics Data System (ADS)

    Broderick, Scott R.; Santhanam, Ganesh Ram; Rajan, Krishna

    2016-07-01

    As the size of databases has significantly increased, whether through high throughput computation or through informatics-based modeling, the challenge of selecting the optimal material for specific design requirements has also arisen. Given the multiple, and often conflicting, design requirements, this selection process is not as trivial as sorting the database for a given property value. We suggest that the materials selection process should minimize selector bias, as well as take data uncertainty into account. For this reason, we discuss and apply decision theory for identifying chemical additions to Ni-base alloys. We demonstrate and compare results for both a computational array of chemistries and standard commercial superalloys. We demonstrate how we can use decision theory to select the best chemical additions for enhancing both property and processing, which would not otherwise be easily identifiable. This work is one of the first examples of introducing the mathematical framework of set theory and decision analysis into the domain of the materials selection process.

  14. Interfacial Properties and Design of Functional Energy Materials

    SciTech Connect

    Sumpter, Bobby G; Liang, Liangbo; Nicolai, Adrien; Meunier, V.

    2014-01-01

    The vital importance of energy to society continues to demand a relentless pursuit of energy responsive materials that can bridge fundamental chemical structures at the molecular level and achieve improved functionality, such as efficient energy conversion/storage/transmission, over multiple length scales. This demand can potentially be realized by harnessing the power of self-assembly a spontaneous process where molecules or much larger entities form ordered aggregates as a consequence of predominately non-covalent (weak) interactions. Self-assembly is the key to bottom-up design of molecular devices, because the nearly atomic-level control is very difficult to realize in a top-down, e.g., lithographic approach. However, while function (e.g., charge mobility) in simple systems such as single crystals can often be predicted, predicting the function of the great variety of self-assembled molecular architectures is complicated by the lack of understanding and control over nanoscale interactions, mesoscale architectures, and macroscale (long-range) order. To establish a foundation toward delivering practical solutions, it is critical to develop an understanding of the chemical and physical mechanisms responsible for the self-assembly of molecular and hybrid materials on various substrates. Typically molecular self-assembly involves poorly understood non-covalent intermolecular and substrate-molecule interactions compounded by local and/or collective influences from the substrate atomic lattice (symmetry and/or topological features) and electronic structure. Thus, progress towards unraveling the underlying physicochemical processes that control the structure and macroscopic physical, mechanical, electrical, and transport properties of materials increasingly requires tight integration of theory, modeling and simulation with precision synthesis, advanced experimental characterization, and device measurements. In this mode, theory and simulation can greatly accelerate the

  15. A domain-specific design architecture for composite material design and aircraft part redesign

    NASA Technical Reports Server (NTRS)

    Punch, W. F., III; Keller, K. J.; Bond, W.; Sticklen, J.

    1992-01-01

    Advanced composites have been targeted as a 'leapfrog' technology that would provide a unique global competitive position for U.S. industry. Composites are unique in the requirements for an integrated approach to designing, manufacturing, and marketing of products developed utilizing the new materials of construction. Numerous studies extending across the entire economic spectrum of the United States from aerospace to military to durable goods have identified composites as a 'key' technology. In general there have been two approaches to composite construction: build models of a given composite materials, then determine characteristics of the material via numerical simulation and empirical testing; and experience-directed construction of fabrication plans for building composites with given properties. The first route sets a goal to capture basic understanding of a device (the composite) by use of a rigorous mathematical model; the second attempts to capture the expertise about the process of fabricating a composite (to date) at a surface level typically expressed in a rule based system. From an AI perspective, these two research lines are attacking distinctly different problems, and both tracks have current limitations. The mathematical modeling approach has yielded a wealth of data but a large number of simplifying assumptions are needed to make numerical simulation tractable. Likewise, although surface level expertise about how to build a particular composite may yield important results, recent trends in the KBS area are towards augmenting surface level problem solving with deeper level knowledge. Many of the relative advantages of composites, e.g., the strength:weight ratio, is most prominent when the entire component is designed as a unitary piece. The bottleneck in undertaking such unitary design lies in the difficulty of the re-design task. Designing the fabrication protocols for a complex-shaped, thick section composite are currently very difficult. It is in

  16. Conceptual design report: Nuclear materials storage facility renovation. Part 1, Design concept. Part 2, Project management

    SciTech Connect

    1995-07-14

    The Nuclear Materials Storage Facility (NMSF) at the Los Alamos National Laboratory (LANL) was a Fiscal Year (FY) 1984 line-item project completed in 1987 that has never been operated because of major design and construction deficiencies. This renovation project, which will correct those deficiencies and allow operation of the facility, is proposed as an FY 97 line item. The mission of the project is to provide centralized intermediate and long-term storage of special nuclear materials (SNM) associated with defined LANL programmatic missions and to establish a centralized SNM shipping and receiving location for Technical Area (TA)-55 at LANL. Based on current projections, existing storage space for SNM at other locations at LANL will be loaded to capacity by approximately 2002. This will adversely affect LANUs ability to meet its mission requirements in the future. The affected missions include LANL`s weapons research, development, and testing (WRD&T) program; special materials recovery; stockpile survelliance/evaluation; advanced fuels and heat sources development and production; and safe, secure storage of existing nuclear materials inventories. The problem is further exacerbated by LANL`s inability to ship any materials offsite because of the lack of receiver sites for mate rial and regulatory issues. Correction of the current deficiencies and enhancement of the facility will provide centralized storage close to a nuclear materials processing facility. The project will enable long-term, cost-effective storage in a secure environment with reduced radiation exposure to workers, and eliminate potential exposures to the public. This document provides Part I - Design Concept which describes the selected solution, and Part II - Project Management which describes the management system organization, the elements that make up the system, and the control and reporting system.

  17. EXPERIMENTAL STUDIES ON PARTICLE IMPACTION AND BOUNCE: EFFECTS OF SUBSTRATE DESIGN AND MATERIAL. (R825270)

    EPA Science Inventory

    This paper presents an experimental investigation of the effects of impaction substrate designs and material in reducing particle bounce and reentrainment. Particle collection without coating by using combinations of different impaction substrate designs and surface materials was...

  18. Large enhancement of interface second-harmonic generation near the zero-n(-) gap of a negative-index Bragg grating.

    PubMed

    D'Aguanno, Giuseppe; Mattiucci, Nadia; Bloemer, Mark J; Scalora, Michael

    2006-03-01

    We predict a large enhancement of interface second-harmonic generation near the zero-n(-) gap of a Bragg grating made of alternating layers of negative- and positive-index materials. Field localization and coherent oscillations of the nonlinear dipoles located at the structure's interfaces conspire to yield conversion efficiencies at least an order of magnitude greater than those achievable in the same length of nonlinear, phase-matched bulk material. These findings thus point to a new class of second-harmonic-generation devices made of standard centrosymmetric materials. PMID:16605673

  19. 46 CFR 160.076-17 - Approval of design or material changes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Approval of design or material changes. 160.076-17... Flotation Devices § 160.076-17 Approval of design or material changes. (a) The manufacturer must submit any proposed changes in design, material, or construction to the recognized laboratory and the Commandant...

  20. 14 CFR 23.613 - Material strength properties and design values.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... item is tested before use to determine that the actual strength properties of that particular item will... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Material strength properties and design... Design and Construction § 23.613 Material strength properties and design values. (a) Material...

  1. 14 CFR 23.613 - Material strength properties and design values.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... item is tested before use to determine that the actual strength properties of that particular item will... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Material strength properties and design... Design and Construction § 23.613 Material strength properties and design values. (a) Material...

  2. 14 CFR 23.613 - Material strength properties and design values.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... item is tested before use to determine that the actual strength properties of that particular item will... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Material strength properties and design... Design and Construction § 23.613 Material strength properties and design values. (a) Material...

  3. 14 CFR 23.613 - Material strength properties and design values.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... item is tested before use to determine that the actual strength properties of that particular item will... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Material strength properties and design... Design and Construction § 23.613 Material strength properties and design values. (a) Material...

  4. 14 CFR 23.613 - Material strength properties and design values.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... item is tested before use to determine that the actual strength properties of that particular item will... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Material strength properties and design... Design and Construction § 23.613 Material strength properties and design values. (a) Material...

  5. Design and development of advanced castable refractory materials

    NASA Astrophysics Data System (ADS)

    Davis, Robert Bruce

    New formulations of castable refractory composite materials were studied. This technology is used to produce low cost composite concrete structures designed for high temperature stability, superior wear resistance and improved strength. An in situ fired, castable cement installation is a heterogeneous structure divided into three zones according to the temperature history and microstructure. The properties of each zone depend on the predominant bonding mode between constituents. Each zone has a characteristic microstructure that influences the integrity of the monolith. The hot side may have a highly dense and developed network of ceramic bonds between constituent particles while the cold side may never reach temperatures sufficient to drive off free water. The thermal, structural and tribological properties depend on the microstructure and the type of bonding that holds the monolith together. The phase distributions are defined by sets of metastable phase conditions driven by the local hydrated chemistry, nearest neighbor oxide compounds, impurities and sintering temperature. Equilibrium phase diagrams were used to select optimum compositions based on higher melting point phases. The phase diagrams were also used to target high temperature phase fields that are stable over wide temperature and stoichiometric ranges. Materials selection of candidate hydraulic clinkers, high temperature oxides, and reinforcement phases were based on requirements for high temperature stability. The calcium aluminate (CaO-Al2O3) and calcium dialuminate (CaO-(Al2O3)2) are common refractory clinkers used in castable refractory cements. The thermodynamics and kinetics of cement hydrate formation are well studied and suited to become the building block of a design for a superior refractory castable cement. The inert oxides mixed with the calcium aluminate clinkers are magnesia (MgO), alumina (Al 2O3), spinel (MgAl2O4) and chromic (Cr2O3). The bulk of the experiments concentrated in the Al

  6. Eutectics as improved pharmaceutical materials: design, properties and characterization.

    PubMed

    Cherukuvada, Suryanarayan; Nangia, Ashwini

    2014-01-28

    Eutectics are a long known class of multi-component solids with important and useful applications in daily life. In comparison to other multi-component crystalline solids, such as salts, solid solutions, molecular complexes and cocrystals, eutectics are less studied in terms of molecular structure organization and bonding interactions. Classically, a eutectic is defined based on its low melting point compared to the individual components. In this article, we attempt to define eutectics not just based on thermal methods but from a structural organization view point, and discuss their microstructures and properties as organic materials vis-a-vis solid solutions and cocrystals. The X-ray crystal structure of a cocrystal is different from that of the individual components whereas the unit cell of a solid solution is similar to that of one of the components. Eutectics are closer to the latter species in that their crystalline arrangement is similar to the parent components but they are different with respect to the structural integrity. A solid solution possesses structural homogeneity throughout the structure (single phase) but a eutectic is a heterogeneous ensemble of individual components whose crystal structures are like discontinuous solid solutions (phase separated). Thus, a eutectic may be better defined as a conglomerate of solid solutions. A structural analysis of cocrystals, solid solutions and eutectics has led to an understanding that materials with strong adhesive (hetero) interactions between the unlike components will lead to cocrystals whereas those having stronger cohesive (homo/self) interactions will more often give rise to solid solutions (for similar structures of components) and eutectics (for different structures of components). We demonstrate that the same crystal engineering principles which have been profitably utilized for cocrystal design in the past decade can now be applied to make eutectics as novel composite materials, illustrated by

  7. Accelerated search for materials with targeted properties by adaptive design

    NASA Astrophysics Data System (ADS)

    Xue, Dezhen; Balachandran, Prasanna V.; Hogden, John; Theiler, James; Xue, Deqing; Lookman, Turab

    2016-04-01

    Finding new materials with targeted properties has traditionally been guided by intuition, and trial and error. With increasing chemical complexity, the combinatorial possibilities are too large for an Edisonian approach to be practical. Here we show how an adaptive design strategy, tightly coupled with experiments, can accelerate the discovery process by sequentially identifying the next experiments or calculations, to effectively navigate the complex search space. Our strategy uses inference and global optimization to balance the trade-off between exploitation and exploration of the search space. We demonstrate this by finding very low thermal hysteresis (ΔT) NiTi-based shape memory alloys, with Ti50.0Ni46.7Cu0.8Fe2.3Pd0.2 possessing the smallest ΔT (1.84 K). We synthesize and characterize 36 predicted compositions (9 feedback loops) from a potential space of ~800,000 compositions. Of these, 14 had smaller ΔT than any of the 22 in the original data set.

  8. Accelerated search for materials with targeted properties by adaptive design.

    PubMed

    Xue, Dezhen; Balachandran, Prasanna V; Hogden, John; Theiler, James; Xue, Deqing; Lookman, Turab

    2016-01-01

    Finding new materials with targeted properties has traditionally been guided by intuition, and trial and error. With increasing chemical complexity, the combinatorial possibilities are too large for an Edisonian approach to be practical. Here we show how an adaptive design strategy, tightly coupled with experiments, can accelerate the discovery process by sequentially identifying the next experiments or calculations, to effectively navigate the complex search space. Our strategy uses inference and global optimization to balance the trade-off between exploitation and exploration of the search space. We demonstrate this by finding very low thermal hysteresis (ΔT) NiTi-based shape memory alloys, with Ti50.0Ni46.7Cu0.8Fe2.3Pd0.2 possessing the smallest ΔT (1.84 K). We synthesize and characterize 36 predicted compositions (9 feedback loops) from a potential space of ∼800,000 compositions. Of these, 14 had smaller ΔT than any of the 22 in the original data set. PMID:27079901

  9. Accelerated search for materials with targeted properties by adaptive design

    PubMed Central

    Xue, Dezhen; Balachandran, Prasanna V.; Hogden, John; Theiler, James; Xue, Deqing; Lookman, Turab

    2016-01-01

    Finding new materials with targeted properties has traditionally been guided by intuition, and trial and error. With increasing chemical complexity, the combinatorial possibilities are too large for an Edisonian approach to be practical. Here we show how an adaptive design strategy, tightly coupled with experiments, can accelerate the discovery process by sequentially identifying the next experiments or calculations, to effectively navigate the complex search space. Our strategy uses inference and global optimization to balance the trade-off between exploitation and exploration of the search space. We demonstrate this by finding very low thermal hysteresis (ΔT) NiTi-based shape memory alloys, with Ti50.0Ni46.7Cu0.8Fe2.3Pd0.2 possessing the smallest ΔT (1.84 K). We synthesize and characterize 36 predicted compositions (9 feedback loops) from a potential space of ∼800,000 compositions. Of these, 14 had smaller ΔT than any of the 22 in the original data set. PMID:27079901

  10. A demonstration of simple airfoils: Structural design and materials choices

    SciTech Connect

    Bunnell, L.R.; Piippo, S.W.

    1993-01-01

    An educational unit is presented for building and evaluating simple wing structures, in order to learn about materials choice and lightweight construction. This unit is appropriate for a high school materials science class or lower-division college courses in structural engineering, materials science, or aeronautical engineering.

  11. Design and material selection for inverter transformer cores

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1973-01-01

    Report is announced which studied magnetic properties of candidate materials for use in spacecraft transformers, static inverters, converters, and transformer-rectifier power supplies. Included are material characteristics for available alloy compositions in tabular form, including: trade names, saturated flux density, dc coercive force, loop squareness, material density, and watts per pound at 3 KHz.

  12. Design and evaluation of lost circulation materials for severe environments

    SciTech Connect

    Loeppke, G.E.; Glowka, D.A.; Wright, E.K.

    1988-01-01

    An independent analysis of lost circulation materials for geothermal applications has been completed using unique laboratory tools developed for the purpose. Test results of commercial materials as well as mathematical models for evaluating their performance are presented. Physical attributes that govern the performance of lost circulation materials are identified and correlated with test results. 9 refs., 27 figs., 4 tabs.

  13. Role of dislocation theory in the design of engineering materials

    SciTech Connect

    Morris, J.W. Jr.

    1980-06-01

    The science of materials development has progressed to a stage in which it is possible to compose a recipe for new materials. The recipe has three steps: given a desirable set of properties and material constraints, one identifies a composition and microstructure to achieve them; given a desirable composition and microstructure, one identifies a processing sequence to achieve them; given a trial alloy, one conducts analytical testing to identify its shortcomings and overcomes them. In effecting each stage of this recipe, it is usually necessary to be aware of and understand the role of the dislocations which determine material properties, define material microstructure, and control its evolution. The role of dislocations is discussed. The text contains examples of particular alloy development efforts, and suggestions for research in dislocation theory which might contribute to the solution of significant problems in materials development.

  14. 46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2014-10-01 2014-10-01 false Hydraulic or pneumatic power and control-materials...

  15. 46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2011-10-01 2011-10-01 false Hydraulic or pneumatic power and control-materials...

  16. 46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2012-10-01 2012-10-01 false Hydraulic or pneumatic power and control-materials...

  17. 46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2013-10-01 2013-10-01 false Hydraulic or pneumatic power and control-materials...

  18. Functionally Graded Designer Viscoelastic Materials Tailored to Perform Prescribed Tasks with Probabilistic Failures and Lifetimes

    SciTech Connect

    Hilton, Harry H.

    2008-02-15

    Protocols are developed for formulating optimal viscoelastic designer functionally graded materials tailored to best respond to prescribed loading and boundary conditions. In essence, an inverse approach is adopted where material properties instead of structures per se are designed and then distributed throughout structural elements. The final measure of viscoelastic material efficacy is expressed in terms of failure probabilities vs. survival time000.

  19. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.220 Class II non-vital systems—materials and pressure design. (a) Except as provided by §§ 128.230, 128.240, and... 46 Shipping 4 2011-10-01 2011-10-01 false Class II non-vital systems-materials and pressure...

  20. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Class II non-vital systems-materials and pressure design. 128.220 Section 128.220 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.220 Class II non-vital systems—materials and...

  1. Design Considerations of Help Options in Computer-Based L2 Listening Materials Informed by Participatory Design

    ERIC Educational Resources Information Center

    Cárdenas-Claros, Mónica Stella

    2015-01-01

    This paper reports on the findings of two qualitative exploratory studies that sought to investigate design features of help options in computer-based L2 listening materials. Informed by principles of participatory design, language learners, software designers, language teachers, and a computer programmer worked collaboratively in a series of…

  2. 46 CFR 164.019-9 - Procedure for acceptance of revisions of design, process, or materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) The manufacturer shall not change the design, material, manufacturing process, or construction of a... requests for acceptance of revisions in design, material, manufacturing process, or construction of a non... 46 Shipping 6 2010-10-01 2010-10-01 false Procedure for acceptance of revisions of design,...

  3. 46 CFR 164.019-9 - Procedure for acceptance of revisions of design, process, or materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) The manufacturer shall not change the design, material, manufacturing process, or construction of a... requests for acceptance of revisions in design, material, manufacturing process, or construction of a non... 46 Shipping 6 2012-10-01 2012-10-01 false Procedure for acceptance of revisions of design,...

  4. 46 CFR 164.019-9 - Procedure for acceptance of revisions of design, process, or materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) The manufacturer shall not change the design, material, manufacturing process, or construction of a... requests for acceptance of revisions in design, material, manufacturing process, or construction of a non... 46 Shipping 6 2013-10-01 2013-10-01 false Procedure for acceptance of revisions of design,...

  5. 46 CFR 164.019-9 - Procedure for acceptance of revisions of design, process, or materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) The manufacturer shall not change the design, material, manufacturing process, or construction of a... requests for acceptance of revisions in design, material, manufacturing process, or construction of a non... 46 Shipping 6 2011-10-01 2011-10-01 false Procedure for acceptance of revisions of design,...

  6. 46 CFR 164.019-9 - Procedure for acceptance of revisions of design, process, or materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) The manufacturer shall not change the design, material, manufacturing process, or construction of a... requests for acceptance of revisions in design, material, manufacturing process, or construction of a non... 46 Shipping 6 2014-10-01 2014-10-01 false Procedure for acceptance of revisions of design,...

  7. Technologists Talk: Making the Links between Design, Problem-Solving and Experiences with Hard Materials

    ERIC Educational Resources Information Center

    Potter, Patricia

    2013-01-01

    Design and problem-solving is a key learning focus in technology education and remains a distinguishing factor that separates it from other subject areas. This research investigated how two expert designers considered experiences with hard materials contributed to their learning design and problem-solving with these materials. The research project…

  8. 30 CFR 36.20 - Quality of material, workmanship, and design.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Quality of material, workmanship, and design...-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.20 Quality of material, workmanship, and design. (a) MSHA will test only equipment that in the opinion of its...

  9. 30 CFR 36.20 - Quality of material, workmanship, and design.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Quality of material, workmanship, and design...-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.20 Quality of material, workmanship, and design. (a) MSHA will test only equipment that in the opinion of its...

  10. 30 CFR 36.20 - Quality of material, workmanship, and design.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Quality of material, workmanship, and design...-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.20 Quality of material, workmanship, and design. (a) MSHA will test only equipment that in the opinion of its...

  11. 30 CFR 27.20 - Quality of material, workmanship, and design.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Quality of material, workmanship, and design... TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS METHANE-MONITORING SYSTEMS Construction and Design Requirements § 27.20 Quality of material, workmanship, and design. (a) MSHA will test only equipment that,...

  12. 46 CFR 128.230 - Penetrations of hulls and watertight bulkheads-materials and pressure design.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... and pressure design. 128.230 Section 128.230 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.230 Penetrations of hulls and watertight bulkheads—materials and pressure design. (a) Each...

  13. 46 CFR 128.230 - Penetrations of hulls and watertight bulkheads-materials and pressure design.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... and pressure design. 128.230 Section 128.230 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.230 Penetrations of hulls and watertight bulkheads—materials and pressure design. (a) Each...

  14. The Design of Reactions, Catalysts and Materials with Aromatic Ions

    NASA Astrophysics Data System (ADS)

    Bandar, Jeffrey Scott

    This thesis details the use of aromatic ions, especially aminocyclopropenium ions, as empowering design elements in the development of new chemical reactions, organic catalysts and polymeric materials. A particular focus is placed throughout on understanding the relationship between the structure of aromatic ions and their performance in these novel applications. Additionally, the benefits that aromatic ions provide in these contexts are highlighted. The first chapter briefly summarizes the Lambert Group's prior efforts toward exploiting the unique reactivity profiles of aromatic ions in the context of new reaction design. Also provided in the first chapter is a comprehensive literature review of aminocyclopropenium ions, upon which the majority of advances described in this thesis are based. To set the stage for the first application of aminocyclopropenium ions, Chapter 2 provides an account of existing highly Bronsted basic functional groups, including guanidines, proazaphosphatranes and iminophosphoranes. The provided review on the synthesis and use in asymmetric catalysis of these bases indicates that there is a high need for conceptually new Bronsted basic functional groups. To address this need, the development of chiral 2,3-bis(dialkylamino)cyclopropenimines as a new platform for asymmetric Bronsted base catalysis is described in Chapter 3. This new class of Bronsted base is readily synthesized on scale, operates efficiently under practical conditions, and greatly outperforms closely related guanidine-based catalysts. Structure-activity relationship studies, mechanistic experiments and computational transition state modeling are all discussed in the context of asymmetric glycinate imine Michael reactions in order to arrive at a working model for cyclopropenimine chemistry. Cumulatively, this chapter provides a "user's guide" to understanding and developing further applications of 2,3-bis(dialkylamino)cyclopropenimines. The use of our optimal chiral 2,3-bis

  15. Materials by Design-A Perspective From Atoms to Structures.

    PubMed

    Buehler, Markus J

    2013-02-01

    Biological materials are effectively synthesized, controlled, and used for a variety of purposes-in spite of limitations in energy, quality, and quantity of their building blocks. Whereas the chemical composition of materials in the living world plays a some role in achieving functional properties, the way components are connected at different length scales defines what material properties can be achieved, how they can be altered to meet functional requirements, and how they fail in disease states and other extreme conditions. Recent work has demonstrated this by using large-scale computer simulations to predict materials properties from fundamental molecular principles, combined with experimental work and new mathematical techniques to categorize complex structure-property relationships into a systematic framework. Enabled by such categorization, we discuss opportunities based on the exploitation of concepts from distinct hierarchical systems that share common principles in how function is created, linking music to materials science. PMID:24163499

  16. Mechanical design engineering. NASA/university advanced design program: Lunar Bulk Material Transport Vehicle

    NASA Technical Reports Server (NTRS)

    Daugherty, Paul; Griner, Stewart; Hendrix, Alan; Makarov, Chris; Martiny, Stephen; Meyhoefer, Douglas Ralph; Platt, Cody Claxton; Sivak, John; Wheeler, Elizabeth Fitch

    1988-01-01

    The design of a Lunar Bulk Material Transport Vehicle (LBMTV) is discussed. Goals set in the project include a payload of 50 cubic feet of lunar soil with a lunar of approximately 800 moon-pounds, a speed of 15 mph, and the ability to handle a grade of 20 percent. Thermal control, an articulated steering mechanism, a dump mechanism, a self-righting mechanism, viable power sources, and a probable control panel are analyzed. The thermal control system involves the use of small strip heaters to heat the housing of electronic equipment in the absence of sufficient solar radiation and multi-layer insulation during periods of intense solar radiation. The entire system uses only 10 W and weighs about 60 pounds, or 10 moon-pounds. The steering mechanism is an articulated steering joint at the center of the vehicle. It utilizes two actuators and yields a turning radius of 10.3 feet. The dump mechanism rotates the bulk material container through an angle of 100 degree using one actuator. The self-righting mechanism consists of two four bar linkages, each of which is powered by the same size actuator as the other linkages. The LBMTV is powered by rechargeable batteries. A running time of at least two hours is attained under a worst case analysis. The weight of the batteries is 100 pounds. A control panel consisting of feedback and control instruments is described. The panel includes all critical information necessary to control the vehicle remotely. The LBMTV is capable of handling many types of cargo. It is able to interface with many types of removable bulk material containers. These containers are made to interface with the three-legged walker, SKITTER. The overall vehicle is about 15 feet in length and has a weight of about 1000 pounds, or 170 lunar pounds.

  17. Mechanical design engineering. NASA/university advanced design program: Lunar Bulk Material Transport Vehicle

    NASA Astrophysics Data System (ADS)

    Daugherty, Paul; Griner, Stewart; Hendrix, Alan; Makarov, Chris; Martiny, Stephen; Meyhoefer, Douglas Ralph; Platt, Cody Claxton; Sivak, John; Wheeler, Elizabeth Fitch

    1988-06-01

    The design of a Lunar Bulk Material Transport Vehicle (LBMTV) is discussed. Goals set in the project include a payload of 50 cubic feet of lunar soil with a lunar of approximately 800 moon-pounds, a speed of 15 mph, and the ability to handle a grade of 20 percent. Thermal control, an articulated steering mechanism, a dump mechanism, a self-righting mechanism, viable power sources, and a probable control panel are analyzed. The thermal control system involves the use of small strip heaters to heat the housing of electronic equipment in the absence of sufficient solar radiation and multi-layer insulation during periods of intense solar radiation. The entire system uses only 10 W and weighs about 60 pounds, or 10 moon-pounds. The steering mechanism is an articulated steering joint at the center of the vehicle. It utilizes two actuators and yields a turning radius of 10.3 feet. The dump mechanism rotates the bulk material container through an angle of 100 degree using one actuator. The self-righting mechanism consists of two four bar linkages, each of which is powered by the same size actuator as the other linkages. The LBMTV is powered by rechargeable batteries. A running time of at least two hours is attained under a worst case analysis. The weight of the batteries is 100 pounds. A control panel consisting of feedback and control instruments is described. The panel includes all critical information necessary to control the vehicle remotely. The LBMTV is capable of handling many types of cargo. It is able to interface with many types of removable bulk material containers. These containers are made to interface with the three-legged walker, SKITTER. The overall vehicle is about 15 feet in length and has a weight of about 1000 pounds, or 170 lunar pounds.

  18. Towards intelligent microstructural design of Nanocomposite Materials. Lightweight, high strength structural/armor materials for service in extreme environments

    SciTech Connect

    Mara, Nathan Allan; Bronkhorst, Curt Allan; Beyerlein, Irene Jane

    2015-12-21

    The intent of this research effort is to prove the hypothesis that: Through the employment of controlled processing parameters which are based upon integrated advanced material characterization and multi-physics material modeling, bulk nanolayered composites can be designed to contain high densities of preferred interfaces that can serve as supersinks for the defects responsible for premature damage and failure.

  19. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.220 Class II... a corrosion-resistant material and, if ferrous, be hot-dip galvanized or be at least of...

  20. Design of Meta-Materials Outside the Homogenization Limit Using Multiscale Analysis and Topology Optimization

    NASA Astrophysics Data System (ADS)

    Czech, Christopher

    The field of meta-materials engineering has largely expanded mechanical design possibilities over the last two decades; some notable design advances include the systematic engineering of negative Poisson's ratio materials and functionally graded materials, materials designed for optimal electronic and thermo-mechanical performances, and the design of materials under uncertainty. With these innovations, the systematic engineering of materials for design-specific uses is becoming more common in industrial and military uses. The motivation for this body of research is the design of the shear beam for a non-pneumatic wheel. Previously, a design optimization of a finite element model of the non-pneumatic wheel was completed, where a linear elastic material was simulated in the shear beam to reduce hysteretic energy losses. As part of the optimization, a set of optimal orthotropic material properties and other geometric properties were identified for the shear beam. Given that no such natural linear elastic material exists, a meta-material can be engineered that meets these properties using the aforementioned tools. However, manufacturing constraints prevent the use of standard homogenization analysis and optimization tools in the engineering of the shear beam due to limitations in the accuracy of the homogenization process for thin materials. In this research, the more general volume averaging analysis is shown to be an accurate tool for meta-material analysis for engineering thin-layered materials. Given an accurate analysis method, several optimization formulations are proposed, and optimality conditions are derived to determine the most mathematically feasible and numerically reliable formulation for topology optimization of a material design problem using a continuous material interpolation over the design domain. This formulation is implemented to engineer meta-materials for problems using the volume averaging analysis, which includes the use of variable linking

  1. MINIMIZING THE ENVIRONMENTAL IMPACT OF CONSTRUCTION MATERIALS IN PLAYGROUND DESIGN

    EPA Science Inventory

    We are a playground design team at Louisiana State University that has been involved with playground design projects for the past seven years. Playgrounds are extremely important to society because they promote the physical, mental, and social well being of children. ...

  2. First Materials Science Research Rack Capabilities and Design Features

    NASA Technical Reports Server (NTRS)

    Schaefer, D.; King, R.; Cobb, S.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The first Materials Science Research Rack (MSRR-1) will accommodate dual Experiment Modules (EM's) and provide simultaneous on-orbit processing operations capability. The first international Materials Science Experiment Module for the MSRR-1 is an international cooperative research activity between NASA's Marshall Space Flight Center (MSFC) and the European Space Agency's (ESA) European Space Research and Technology Center. (ESTEC). This International Standard Payload Rack (ISPR) will contain the Materials Science Laboratory (MSL) developed by ESA as an Experiment Module. The MSL Experiment Module will accommodate several on-orbit exchangeable experiment-specific Module Inserts. Module Inserts currently planned are a Quench Module Insert, Low Gradient Furnace, Solidification with Quench Furnace, and Diffusion Module Insert. The second Experiment Module for the MSRR-1 configuration is a commercial device supplied by MSFC's Space Products Department (SPD). It includes capabilities for vapor transport processes and liquid metal sintering. This Experiment Module will be replaced on-orbit with other NASA Materials Science EMs.

  3. Synthesis and design of intermetallic materials - molybdenum disilicide

    SciTech Connect

    Petrovic, J.J.; Castro, R.G.; Butt, D.P.

    1995-05-01

    The objective of this program is to develop structural silicide-based composite materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation resistance for applications of importance to the U.S. processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature composite materials and important applications in major energy-intensive U.S. processing industries. The program presently has a number of developing industrial connections, including a CRADA with the advanced materials company Advanced Refractory Technologies Inc. and interactions targeted at developing industrial gas burner and metal and glass melting/processing applications. Current experimental emphasis is on the development and characterization of SiC reinforced-MoSi{sub 2} matrix composites, plasma sprayed MoSi{sub 2}-based materials and microlaminate composites, and MoSi{sub 2} reinforced-Si{sub 3}N{sub 4} matrix composites. We are developing processing methods for MoSi{sub 2{minus}}based materials and microlaminate composites, and MoSi{sub 2} reinforced-Si{sub 3}N{sub 4} matrix composites. We are developing processing methods for MoSi{sub 2{minus}} based materials, such as plasma spraying/spray forming and electrophoretic deposition. We are also pursuing the fabrication of prototype industrial gas burner and injection tube components of these materials, as well as prototype components for glass processing.

  4. Advanced computational research in materials processing for design and manufacturing

    SciTech Connect

    Zacharia, T.

    1995-04-01

    Advanced mathematical techniques and computer simulation play a major role in providing enhanced understanding of conventional and advanced materials processing operations. Development and application of mathematical models and computer simulation techniques can provide a quantitative understanding of materials processes and will minimize the need for expensive and time consuming trial- and error-based product development. As computer simulations and materials databases grow in complexity, high performance computing and simulation are expected to play a key role in supporting the improvements required in advanced material syntheses and processing by lessening the dependence on expensive prototyping and re-tooling. Many of these numerical models are highly compute-intensive. It is not unusual for an analysis to require several hours of computational time on current supercomputers despite the simplicity of the models being studied. For example, to accurately simulate the heat transfer in a 1-m{sup 3} block using a simple computational method requires 10`2 arithmetic operations per second of simulated time. For a computer to do the simulation in real time would require a sustained computation rate 1000 times faster than that achievable by current supercomputers. Massively parallel computer systems, which combine several thousand processors able to operate concurrently on a problem are expected to provide orders of magnitude increase in performance. This paper briefly describes advanced computational research in materials processing at ORNL. Continued development of computational techniques and algorithms utilizing the massively parallel computers will allow the simulation of conventional and advanced materials processes in sufficient generality.

  5. Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth.

    PubMed

    Manso, Sandra; De Muynck, Willem; Segura, Ignacio; Aguado, Antonio; Steppe, Kathy; Boon, Nico; De Belie, Nele

    2014-05-15

    Ordinary Portland cement (OPC), the most used binder in construction, presents some disadvantages in terms of pollution (CO2 emissions) and visual impact. For this reason, green roofs and façades have gain considerable attention in the last decade as a way to integrate nature in cities. These systems, however, suffer from high initial and maintenance costs. An alternative strategy to obtain green facades is the direct natural colonisation of the cementitious construction materials constituting the wall, a phenomenon governed by the bioreceptivity of such material. This work aims at assessing the suitability of magnesium phosphate cement (MPC) materials to allow a rapid natural colonisation taking carbonated OPC samples as a reference material. For that, the aggregate size, the w/c ratio and the amount of cement paste of mortars made of both binders were modified. The assessment of the different bioreceptivities was conducted by means of an accelerated algal fouling test. MPC samples exhibited a faster fouling compared to OPC samples, which could be mainly attributed to the lower pH of the MPC binder. In addition to the binder, the fouling rate was governed by the roughness and the porosity of the material. MPC mortar with moderate porosity and roughness appears to be the most feasible material to be used for the development of green concrete walls. PMID:24602907

  6. Advanced computational research in materials processing for design and manufacturing

    SciTech Connect

    Zacharia, T.

    1994-12-31

    The computational requirements for design and manufacture of automotive components have seen dramatic increases for producing automobiles with three times the mileage. Automotive component design systems are becoming increasingly reliant on structural analysis requiring both overall larger analysis and more complex analyses, more three-dimensional analyses, larger model sizes, and routine consideration of transient and non-linear effects. Such analyses must be performed rapidly to minimize delays in the design and development process, which drives the need for parallel computing. This paper briefly describes advanced computational research in superplastic forming and automotive crash worthiness.

  7. New Materials Design Through Friction Stir Processing Techniques

    SciTech Connect

    Buffa, G.; Fratini, L.; Shivpuri, R.

    2007-04-07

    Friction Stir Welding (FSW) has reached a large interest in the scientific community and in the last years also in the industrial environment, due to the advantages of such solid state welding process with respect to the classic ones. The complex material flow occurring during the process plays a fundamental role in such solid state welding process, since it determines dramatic changes in the material microstructure of the so called weld nugget, which affects the effectiveness of the joints. What is more, Friction Stir Processing (FSP) is mainly being considered for producing high-strain-rate-superplastic (HSRS) microstructure in commercial aluminum alloys. The aim of the present research is the development of a locally composite material through the Friction Stir Processing (FSP) of two AA7075-T6 blanks and a different material insert. The results of a preliminary experimental campaign, carried out at the varying of the additional material placed at the sheets interface under different conditions, are presented. Micro and macro observation of the such obtained joints permitted to investigate the effects of such process on the overall joint performance.

  8. New Materials Design Through Friction Stir Processing Techniques

    NASA Astrophysics Data System (ADS)

    Buffa, G.; Fratini, L.; Shivpuri, R.

    2007-04-01

    Friction Stir Welding (FSW) has reached a large interest in the scientific community and in the last years also in the industrial environment, due to the advantages of such solid state welding process with respect to the classic ones. The complex material flow occurring during the process plays a fundamental role in such solid state welding process, since it determines dramatic changes in the material microstructure of the so called weld nugget, which affects the effectiveness of the joints. What is more, Friction Stir Processing (FSP) is mainly being considered for producing high-strain-rate-superplastic (HSRS) microstructure in commercial aluminum alloys. The aim of the present research is the development of a locally composite material through the Friction Stir Processing (FSP) of two AA7075-T6 blanks and a different material insert. The results of a preliminary experimental campaign, carried out at the varying of the additional material placed at the sheets interface under different conditions, are presented. Micro and macro observation of the such obtained joints permitted to investigate the effects of such process on the overall joint performance.

  9. Microstructure Optimization in Fuel Cell Electrodes using Materials Design

    SciTech Connect

    Li, Dongsheng; Saheli, Ghazal; Khaleel, Mohammad A.; Garmestani, Hamid

    2006-08-01

    Abstract A multiscale model based on statistical continuum mechanics is proposed to predict the mechanical and electrical properties of heterogeneous porous media. This model is applied within the framework of microstructure sensitive design (MSD) to guide the design of the microstructure in porous lanthanum strontium manganite (LSM) fuel cell electrode. To satisfy the property requirement and compatibility, porosity and its distribution can be adjusted under the guidance of MSD to achieve optimized microstructure.

  10. Stratification, Elaboration and Formalisation of Design Documents: Effects on the Production of Instructional Materials

    ERIC Educational Resources Information Center

    Boot, Eddy W.; Nelson, Jon; van Merrienboer, Jeroen J. G.; Gibbons, Andrew S.

    2007-01-01

    Designers and producers of instructional materials lack a common design language. As a result, producers have difficulties translating design documents into technical specifications. The 3D-model is introduced to improve the stratification, elaboration and formalisation of design documents. It is hypothesised that producers working with improved…

  11. Design of Digital Learning Material on Social-Psychological Theories for Nutrition Behavior Research

    ERIC Educational Resources Information Center

    Busstra, Maria C.; De Graaf, Cees; Hartog, Rob

    2007-01-01

    This article describes the design, implementation and evaluation of digital learning material on the social--psychological Theory of Planned Behavior (TPB) and its use in nutrition behavior research. The design is based on guidelines derived from theories on instructional design. The major component of the design challenge is to implement three…

  12. A database to enable discovery and design of piezoelectric materials

    PubMed Central

    de Jong, Maarten; Chen, Wei; Geerlings, Henry; Asta, Mark; Persson, Kristin Aslaug

    2015-01-01

    Piezoelectric materials are used in numerous applications requiring a coupling between electrical fields and mechanical strain. Despite the technological importance of this class of materials, for only a small fraction of all inorganic compounds which display compatible crystallographic symmetry, has piezoelectricity been characterized experimentally or computationally. In this work we employ first-principles calculations based on density functional perturbation theory to compute the piezoelectric tensors for nearly a thousand compounds, thereby increasing the available data for this property by more than an order of magnitude. The results are compared to select experimental data to establish the accuracy of the calculated properties. The details of the calculations are also presented, along with a description of the format of the database developed to make these computational results publicly available. In addition, the ways in which the database can be accessed and applied in materials development efforts are described. PMID:26451252

  13. Design, chirality, and flexibility in nanoporous molecule-based materials.

    PubMed

    Bradshaw, D; Claridge, J B; Cussen, E J; Prior, T J; Rosseinsky, M J

    2005-04-01

    Scientific and technological interest in porous materials with molecule-sized channels and cavities has led to an intense search for controlled chemical routes to systems with specific properties. This Account details our work on directing the assembly of open-framework structures based on molecules and investigating how the response of nanoporous examples of such materials to guests differs from classical rigid porous systems. The stabilization of chiral nanoporosity by a hierarchy of interactions that both direct and maintain a helical open-framework structure exemplifies the approach. PMID:15835874

  14. Design of a scientific probe for obtaining Mars surface material

    NASA Technical Reports Server (NTRS)

    1990-01-01

    With the recent renewed interest in interplanetary and deep space exploratory missions, the Red Planet, Mars, which has captured people's imagination for centuries, has again become a center of attention. In the late 1960s and early 1970s, a series of Mariner missions performed fly-by investigations of the Mars surface and atmosphere. Later, in the mid 1970s, the data gathered by these earlier Mariner missions provided the basis of the much-publicized Viking missions, whose main objective was to determine the possibility of extraterrestrial life on Mars. More recently, with the dramatic changes in international politics, ambitious joint manned missions between the United States and the Soviet Union have been proposed to be launched in the early 21st century. In light of these exciting developments, the Spacecraft Design course, which was newly established at UCLA under NASA/USRA sponsorship, has developed its curriculum around a design project: the synthesis of an unmanned Martian landing probe. The students are required to conceive a preliminary design of a small spacecraft that is capable of landing at a designated site, collecting soil samples, and then returning the samples to orbit. The goal of the project is to demonstrate the feasibility of such a mission. This preliminary study of an interplanetary exploration mission has shown the feasibility of such a mission. The students have learned valuable lessons about the complexity of spacecraft design, even though the mission is relatively simple.

  15. Designing Competency-Based Materials for the Automotive Mechanics Curriculum

    ERIC Educational Resources Information Center

    Richardson, Roger L.

    1977-01-01

    Describes the Career Education Center's (Florida State University) development of the "Automotive Mechanics Catalog" (a job inventory noting performance objectives for specific occupational programs), using the Vocational-Technical Education Consortium of States (V-TECS) model. Also describes the development of curriculum materials using the…

  16. The Empirical Attitude, Material Practice and Design Activities

    ERIC Educational Resources Information Center

    Apedoe, Xornam; Ford, Michael

    2010-01-01

    This article is an argument about something that is both important and severely underemphasized in most current science curricula. The empirical attitude, fundamental to science since Galileo, is a habit of mind that motivates an active search for feedback on our ideas from the material world. Although more simple views of science manifest the…

  17. A Computational Method for Materials Design of New Interfaces

    NASA Astrophysics Data System (ADS)

    Kaminski, Jakub; Ratsch, Christian; Weber, Justin; Haverty, Michael; Shankar, Sadasivan

    2015-03-01

    We propose a novel computational approach to explore the broad configurational space of possible interfaces formed from known crystal structures to find new heterostructure materials with potentially interesting properties. In a series of steps with increasing complexity and accuracy, the vast number of possible combinations is narrowed down to a limited set of the most promising and chemically compatible candidates. This systematic screening encompasses (i) establishing the geometrical compatibility along multiple crystallographic orientations of two materials, (ii) simple functions eliminating configurations with unfavorable interatomic steric conflicts, (iii) application of empirical and semi-empirical potentials estimating approximate energetics and structures, (iv) use of DFT based quantum-chemical methods to ascertain the final optimal geometry and stability of the interface in question. For efficient high-throughput screening we have developed a new method to calculate surface energies, which allows for fast and systematic treatment of materials terminated with non-polar surfaces. We show that our approach leads to a maximum error around 3% from the exact reference. The representative results from our search protocol will be presented for selected materials including semiconductors and oxides.

  18. Design for a 1 MHz soft magnetic material hysteresisgraph (abstract)

    NASA Astrophysics Data System (ADS)

    Dennison, Eric

    1993-05-01

    Until recently, high frequency (1 MHz) testing of magnetically soft materials has been typically limited to measurement of core loss and peak or inductive ac permeability. A high frequency hysteresisgraph allows direct examination of the hysteresis loop and calculation of values for magnetic parameters such as coercivity (Hc), peak permeability (μp), remanence (Br), core loss (Pc,Pcv,Pcm), bias drive field strength (Hbias), maximum H drive (Hmax) and maximum or saturation induction (Bmax). This paper describes the methods used to construct and calibrate a commercial high frequency magnetic hysteresisgraph which is capable of recording the primary current and secondary voltage waveforms of magnetic cores driven at up to 1 MHz. A system accuracy of 2% (for B and H parameter values) and 5% (for core loss) was achieved through careful control and calibration of signal phase shifts within the circuitry. System calibration, magnetic field calculations, and use of FFT post-processing of the acquired waveforms are discussed. The ability to accurately record the hysteresis loop of a material at 1 MHz allows high frequency core materials to be characterized not only by core loss and permeability, but by their hysteresis loop shape, coercivity, and remanence, both under pure ac and dc biased ac drive conditions. Changes in material characteristics due to dc biasing, temperature variations, defects, or mechanical stresses can be readily observed and described in terms of changes to the hysteresis curve shape.

  19. Photovoltaic module encapsulation design and materials section, volume 2

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.

    1984-01-01

    Tests for chemical structure, material properties, water absorption, aging and curing agent of Ethylene Vinyl Acetate (EVA) and UV absorption studies are carried out. A computer model was developed for thermal optical modeling, to investigate dependence between module operating temperature and solar insolation, and heat dissapation behavior. Structural analyses were performed in order to determine the stress distribution under wind and heat conditions. Curves are shown for thermal loading conditions. An electrical isolation was carried out to investigate electrical stress aging of non-metallic encapsulation materials and limiting material flaws, and to develop a computer model of electrical fields and stresses in encapsulation materials. In addition, a mathematical model was developed and tests were conducted to predict hygroscopic and thermal expansion and contraction on a plastic coated wooden substrate. Thermal cycle and humidity freezing cycle tests, partial discharge tests, and hail impact tests were also carried out. Finally, the effects of soiling on the surface of photovoltaic modules were investigated. Two antisoiling coatings, a fluorinated silane and perflourodecanoic acid were considered.

  20. NANOSTRUCTURED MATERIAL DESIGN FOR HG, AS, AND SE CAPTURE

    EPA Science Inventory

    The goal of this research project is to identify potential materials that can be used as multipollutant sorbents using a hierarchy of computational modeling approaches. Palladium (Pd) and gold (Au) alloys were investigated and the results show that the addition of a small amou...

  1. Handbook for Designing and Writing Distance Education Materials.

    ERIC Educational Resources Information Center

    Gachuhi, D., Ed.; Matiru, B., Ed.

    Developed from a series of workshops in Kenya, this handbook offers practical guidance for those creating printed distance education materials for African students. The introduction describes the workshops and a short section explains how to use the handbook. Twelve units appear on the following topics: (1) overview of distance education; (2)…

  2. Designing for time-dependent material response in spacecraft structures

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Oleksuk, Lynda L. S.; Bowles, D. E.

    1992-01-01

    To study the influence on overall deformations of the time-dependent constitutive properties of fiber-reinforced polymeric matrix composite materials being considered for use in orbiting precision segmented reflectors, simple sandwich beam models are developed. The beam models include layers representing the face sheets, the core, and the adhesive bonding of the face sheets to the core. A three-layer model lumps the adhesive layers with the face sheets or core, while a five-layer model considers the adhesive layers explicitly. The deformation response of the three-layer and five-layer sandwich beam models to a midspan point load is studied. This elementary loading leads to a simple analysis, and it is easy to create this loading in the laboratory. Using the correspondence principle of viscoelasticity, the models representing the elastic behavior of the two beams are transformed into time-dependent models. Representative cases of time-dependent material behavior for the facesheet material, the core material, and the adhesive are used to evaluate the influence of these constituents being time-dependent on the deformations of the beam. As an example of the results presented, if it assumed that, as a worst case, the polymer-dominated shear properties of the core behave as a Maxwell fluid such that under constant shear stress the shear strain increases by a factor of 10 in 20 years, then it is shown that the beam deflection increases by a factor of 1.4 during that time. In addition to quantitative conclusions, several assumptions are discussed which simplify the analyses for use with more complicated material models. Finally, it is shown that the simpler three-layer model suffices in many situations.

  3. Structural design methodologies for ceramic-based material systems

    NASA Technical Reports Server (NTRS)

    Duffy, Stephen F.; Chulya, Abhisak; Gyekenyesi, John P.

    1991-01-01

    One of the primary pacing items for realizing the full potential of ceramic-based structural components is the development of new design methods and protocols. The focus here is on low temperature, fast-fracture analysis of monolithic, whisker-toughened, laminated, and woven ceramic composites. A number of design models and criteria are highlighted. Public domain computer algorithms, which aid engineers in predicting the fast-fracture reliability of structural components, are mentioned. Emphasis is not placed on evaluating the models, but instead is focused on the issues relevant to the current state of the art.

  4. Nonstoichiometric Laser Materials: Designer Wavelengths in Neodymium Doped Garnets

    NASA Technical Reports Server (NTRS)

    Walsh, Brian M.; Barnes, Norman P.

    2008-01-01

    The tunable nature of lasers provides for a wide range of applications. Most applications rely on finding available laser wavelengths to meet the needs of the research. This article presents the concept of compositional tuning, whereby the laser wavelength is designed by exploiting nonstoichiometry. For research where precise wavelengths are required, such as remote sensing, this is highly advantageous. A theoretical basis for the concept is presented and experimental results in spectroscopic measurements support the theoretical basis. Laser operation nicely demonstrates the validity of the concept of designer lasers.

  5. A Practical Approach To Preform Design For Different Materials

    SciTech Connect

    Harrer, Otto; Ruef, Guntram; Buchmayr, Bruno; Sommitsch, Christof

    2007-04-07

    To forge an H-shaped cross section, various preform designs have been tested for steel 42CrMo4, aluminum 7075 and nickel base alloy 80 A (Bohler L306). The influence of different boundary conditions like temperature and friction on the preform and hence on the forming process have been investigated by means of two dimensional finite element analyses. Furthermore, the influence of the preform on the microstructure was computed and the structural damage evolution in the forged parts depending on the preform design has been considered for alloy 80 A.

  6. Mapping Chemical Selection Pathways for Designing Multicomponent Alloys: an informatics framework for materials design

    NASA Astrophysics Data System (ADS)

    Srinivasan, Srikant; Broderick, Scott R.; Zhang, Ruifeng; Mishra, Amrita; Sinnott, Susan B.; Saxena, Surendra K.; Lebeau, James M.; Rajan, Krishna

    2015-12-01

    A data driven methodology is developed for tracking the collective influence of the multiple attributes of alloying elements on both thermodynamic and mechanical properties of metal alloys. Cobalt-based superalloys are used as a template to demonstrate the approach. By mapping the high dimensional nature of the systematics of elemental data embedded in the periodic table into the form of a network graph, one can guide targeted first principles calculations that identify the influence of specific elements on phase stability, crystal structure and elastic properties. This provides a fundamentally new means to rapidly identify new stable alloy chemistries with enhanced high temperature properties. The resulting visualization scheme exhibits the grouping and proximity of elements based on their impact on the properties of intermetallic alloys. Unlike the periodic table however, the distance between neighboring elements uncovers relationships in a complex high dimensional information space that would not have been easily seen otherwise. The predictions of the methodology are found to be consistent with reported experimental and theoretical studies. The informatics based methodology presented in this study can be generalized to a framework for data analysis and knowledge discovery that can be applied to many material systems and recreated for different design objectives.

  7. Mapping Chemical Selection Pathways for Designing Multicomponent Alloys: an informatics framework for materials design

    PubMed Central

    Srinivasan, Srikant; Broderick, Scott R.; Zhang, Ruifeng; Mishra, Amrita; Sinnott, Susan B.; Saxena, Surendra K.; LeBeau, James M.; Rajan, Krishna

    2015-01-01

    A data driven methodology is developed for tracking the collective influence of the multiple attributes of alloying elements on both thermodynamic and mechanical properties of metal alloys. Cobalt-based superalloys are used as a template to demonstrate the approach. By mapping the high dimensional nature of the systematics of elemental data embedded in the periodic table into the form of a network graph, one can guide targeted first principles calculations that identify the influence of specific elements on phase stability, crystal structure and elastic properties. This provides a fundamentally new means to rapidly identify new stable alloy chemistries with enhanced high temperature properties. The resulting visualization scheme exhibits the grouping and proximity of elements based on their impact on the properties of intermetallic alloys. Unlike the periodic table however, the distance between neighboring elements uncovers relationships in a complex high dimensional information space that would not have been easily seen otherwise. The predictions of the methodology are found to be consistent with reported experimental and theoretical studies. The informatics based methodology presented in this study can be generalized to a framework for data analysis and knowledge discovery that can be applied to many material systems and recreated for different design objectives. PMID:26681142

  8. Mapping Chemical Selection Pathways for Designing Multicomponent Alloys: an informatics framework for materials design.

    PubMed

    Srinivasan, Srikant; Broderick, Scott R; Zhang, Ruifeng; Mishra, Amrita; Sinnott, Susan B; Saxena, Surendra K; LeBeau, James M; Rajan, Krishna

    2015-01-01

    A data driven methodology is developed for tracking the collective influence of the multiple attributes of alloying elements on both thermodynamic and mechanical properties of metal alloys. Cobalt-based superalloys are used as a template to demonstrate the approach. By mapping the high dimensional nature of the systematics of elemental data embedded in the periodic table into the form of a network graph, one can guide targeted first principles calculations that identify the influence of specific elements on phase stability, crystal structure and elastic properties. This provides a fundamentally new means to rapidly identify new stable alloy chemistries with enhanced high temperature properties. The resulting visualization scheme exhibits the grouping and proximity of elements based on their impact on the properties of intermetallic alloys. Unlike the periodic table however, the distance between neighboring elements uncovers relationships in a complex high dimensional information space that would not have been easily seen otherwise. The predictions of the methodology are found to be consistent with reported experimental and theoretical studies. The informatics based methodology presented in this study can be generalized to a framework for data analysis and knowledge discovery that can be applied to many material systems and recreated for different design objectives. PMID:26681142

  9. 30 CFR 18.92 - Quality of material and design.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field... shall be designed to facilitate maintenance and inspection. (b) MSHA shall conduct field investigations and, where necessary, field test electric machinery only where such machinery is found to...

  10. 30 CFR 18.92 - Quality of material and design.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field... shall be designed to facilitate maintenance and inspection. (b) MSHA shall conduct field investigations and, where necessary, field test electric machinery only where such machinery is found to...

  11. 30 CFR 18.92 - Quality of material and design.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field... shall be designed to facilitate maintenance and inspection. (b) MSHA shall conduct field investigations and, where necessary, field test electric machinery only where such machinery is found to...

  12. 30 CFR 18.92 - Quality of material and design.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field... shall be designed to facilitate maintenance and inspection. (b) MSHA shall conduct field investigations and, where necessary, field test electric machinery only where such machinery is found to...

  13. 30 CFR 18.92 - Quality of material and design.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field... shall be designed to facilitate maintenance and inspection. (b) MSHA shall conduct field investigations and, where necessary, field test electric machinery only where such machinery is found to...

  14. Design of a scientific probe for obtaining Mars surface material

    NASA Technical Reports Server (NTRS)

    Baker, Miles; Deyerl, Eric; Gibson, Tim; Langberg, Bob; Yee, Terrance (Editor)

    1990-01-01

    The objective is to return a 1 Kg Martian soil sample from the surface of Mars to a mothership in a 60 km Mars orbit. Given here is information on the mission profile, the structural design and component placement, thermal control and guidance, propulsion systems, orbital mechanics, and specialized structures.

  15. Evolutionary Design of a Robotic Material Defect Detection System

    NASA Technical Reports Server (NTRS)

    Ballard, Gary; Howsman, Tom; Craft, Mike; ONeil, Daniel; Steincamp, Jim; Howell, Joe T. (Technical Monitor)

    2002-01-01

    During the post-flight inspection of SSME engines, several inaccessible regions must be disassembled to inspect for defects such as cracks, scratches, gouges, etc. An improvement to the inspection process would be the design and development of very small robots capable of penetrating these inaccessible regions and detecting the defects. The goal of this research was to utilize an evolutionary design approach for the robotic detection of these types of defects. A simulation and visualization tool was developed prior to receiving the hardware as a development test bed. A small, commercial off-the-shelf (COTS) robot was selected from several candidates as the proof of concept robot. The basic approach to detect the defects was to utilize Cadmium Sulfide (CdS) sensors to detect changes in contrast of an illuminated surface. A neural network, optimally designed utilizing a genetic algorithm, was employed to detect the presence of the defects (cracks). By utilization of the COTS robot and US sensors, the research successfully demonstrated that an evolutionarily designed neural network can detect the presence of surface defects.

  16. Recent progress in supercapacitors: from materials design to system construction.

    PubMed

    Wang, Yonggang; Xia, Yongyao

    2013-10-01

    Supercapacitors are currently attracting intensive attention because they can provide energy density by orders of magnitude higher than dielectric capacitors, greater power density, and longer cycling ability than batteries. The main challenge for supercapacitors is to develop them with high energy density that is close to that of a current rechargeable battery, while maintaining their inherent characteristics of high power and long cycling life. Consequently, much research has been devoted to enhance the performance of supercapacitors by either maximizing the specific capacitance and/or increasing the cell voltage. The latest advances in the exploration and development of new supercapacitor systems and related electrode materials are highlighted. Also, the prospects and challenges in practical application are analyzed, aiming to give deep insights into the material science and electrochemical fields. PMID:24089352

  17. Packaging Materials and Design for Improved PV Module Reliability

    SciTech Connect

    Jorgensen, G.; Terwilliger, K.; Kempe, M.; Pern, J.; Glick, S.; del Cueto, J.; Kennedy, C.; McMahon, T.

    2005-01-01

    A number of candidate alternative encapsulant and soft backsheet materials have been evaluated in terms of their suitability for photovoltaic (PV) module packaging applications. Relevant properties, including peel strength as a function of damp heat exposure and permeability, have been measured. Based on these tests, promising new encapsulants with adhesion-promoting primers have been identified that result in improved properties. Test results for backsheets provided by industry and prepared at the National Renewable Energy Laboratory (NREL) have suggested strategies to achieve significantly improved products. The ability of glass/glass and glass/breathable backsheet constructions laminated with various encapsulant and/or edge seal materials to protect thin-film aluminum coatings deposited onto glass substrates was assessed. Glass/glass laminate constructions can trap harmful compounds that catalyze moisture-driven corrosion of the aluminum. Constructions with breathable backsheets allow higher rates of moisture ingress, but also allow egress of deleterious substances that can result in decreased corrosion.

  18. Biochemically designed polymers as self-organized materials

    NASA Astrophysics Data System (ADS)

    Alva, Shridhara; Sarma, Rupmoni; Marx, Kenneth A.; Kumar, Jayant; Tripathy, Sukant K.; Akkara, Joseph A.; Kaplan, David L.

    1997-02-01

    Self assembled molecular systems are a focus of attention for material scientists as they provide an inherent molecular level organization responsible for enhanced material properties. We have developed polymeric molecular systems with interesting optical properties by biochemical engineering, which can be self assembled to thin films. Horseradish peroxidase catalyzed polymerizations of phenolic monomers: 9-hydroxyquinoline-5-sulfonic acid, acid red and decyl ester (d&l isomers) of tyrosine, have been achieved in the presence of hydrogen peroxide. The polymer of 8- hydroxyquinoline-5-sulfonic acid acts as a polymeric ligand that can be used for metal ion sensing. The polymer of acid red, with azo functional groups in the polymer backbone, shows interesting optical properties. Amphiphilic derivatives of tyrosine self assemble into tubules from micelles in aqueous solutions. These tubules have been enzymatically polymerized to polymeric tubules. The tubules are of 5 micrometers average diameter and > 200 micrometers length. The formation and properties of these tubules are discussed.

  19. Theory based design and optimization of materials for spintronics applications

    NASA Astrophysics Data System (ADS)

    Xu, Tianyi

    The Spintronics industry has developed rapidly in the past decade. Finding the right material is very important for Spintronics applications, which requires good understanding of the physics behind specific phenomena. In this dissertation, we will focus on two types of perpendicular transport phenomena, the current-perpendicular-to-plane giant-magneto-resistance (CPP-GMR) phenomenon and the tunneling phenomenon in the magnetic tunnel junctions. The Valet-Fert model is a very useful semi-classical approach for understanding the transport and spin-flip process in CPP-GMR. We will present a finite element based implementation for the Valet-Fert model which enables a practical way to calculate the electron transport in real CPP-GMR spin valves. It is very important to find high spin polarized materials for CPP-GMR spin valves. The half-metal, due to its full spin polarization, is of interest. We will propose a rational way to find half-metals based on the gap theorem. Then we will focus on the high-MR TMR phenomenon. The tunneling theory of electron transport in mesoscopic systems will be covered. Then we will calculate the transport properties of certain junctions with the help of Green's function under the Landauer-Buttiker formalism, also known as the scattering formalism. The damping constant determines the switching rate of a device. We can calculate it using a method based on the Extended Huckel Tight-Binding theory (EHTB). The symmetry filtering effect is very helpful for finding materials for TMR junctions. Based upon which, we find a good candidate material, MnAl, for TMR applications.

  20. Laboratory experiments designed to test the remediation properties of materials

    SciTech Connect

    Gilbert, J.S.; Wildeman, T.R.; Ford, K.L.

    1999-07-01

    Passive treatment systems constructed to remediate mine drainage have proven to be very successful for a wide variety of drainage compositions and volumes. The construction of an anaerobic passive treatment system requires a mixture of local materials with the objective of producing a system that allows adequate water flow while supporting the growth of sulfate-reducing bacteria. These bacteria have the effect of reducing the oxidizing potential in the system causing many sulfide-forming metals in solution to precipitate. The focus of these experiments was the study of chemical characteristics of materials, individually and in mixtures, with the purpose of determining which would be best suited for incorporation into a treatment system. The materials of interest were manure (fresh and aged), alfalfa, limestone, and sawdust, which were all collected in close proximity to the construction site of the proposed treatment system. A variety of chemical and physical hypotheses were formulated prior to performing simple chemical characterization and anaerobic treatment tests. The hypotheses relating to the chemical nature of the single materials were carbon to nitrogen ratio, availability of low molecular weight organic acids, number of adsorption sites, and organic carbon content. In addition, hypotheses concerning the performance of mixtures were evaluated by looking at the relative amount of bacterial growth (and metal removal) seen in each mixture over a 4-week period. The results of the laboratory experiments confirmed hypotheses, and demonstrated that in the mixtures, the anaerobic bacteria flourish when alfalfa is present, up to a point. The best mixture that allowed proliferation of bacteria while also removing metals consisted of 50% limestone, 25% aged manure, 15% sawdust, and 10% alfalfa (% by weight).

  1. SRM nozzle design breakthroughs with advanced composite materials

    NASA Astrophysics Data System (ADS)

    Berdoyes, Michel

    1993-06-01

    The weight reduction-related performance and cost of the Space Shuttle's Solid Rocket Motor (SRM) units' critical nozzle components are undergoing revolutionary improvements through the use of 3D-woven carbon/carbon and carbon/alumina composite materials. These can be used to fabricate the SRM's nozzle throat nondegradable insulators, thermostructural insulator, and exit cones. Additional developments are noted among nozzle-related structural components for additional rocket propulsion systems, including a three-piece extendible nozzle.

  2. Material Development to Raise Awareness of Using Smart Boards: An Example Design and Development Research

    ERIC Educational Resources Information Center

    Günaydin, Serpil; Karamete, Aysen

    2016-01-01

    This study aims to develop training material that will help raise awareness in prospective teachers regarding the benefits of using smart boards in the classroom. In this study, a Type 2 design and development research method (DDR) was used. The material was developed by applying phases of ADDIE--an instructional systems design model. The…

  3. The Effectiveness of Scaffolding Design in Training Writing Skills Physics Teaching Materials

    ERIC Educational Resources Information Center

    Sinaga, Parlindungan; Suhandi, Andi; Liliasari

    2015-01-01

    Result of field studies showed low writing skill of teachers in teaching material. The root of the problem lies in their inability on translating description of teaching material into writing. This research focused on the effectiveness of scaffolding design. The scaffolding design was tested in the selected topics of physics courses for…

  4. 46 CFR 128.230 - Penetrations of hulls and watertight bulkheads-materials and pressure design.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Penetrations of hulls and watertight bulkheads-materials and pressure design. 128.230 Section 128.230 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... § 128.230 Penetrations of hulls and watertight bulkheads—materials and pressure design. (a) Each...

  5. 46 CFR 128.230 - Penetrations of hulls and watertight bulkheads-materials and pressure design.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Penetrations of hulls and watertight bulkheads-materials and pressure design. 128.230 Section 128.230 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... § 128.230 Penetrations of hulls and watertight bulkheads—materials and pressure design. (a) Each...

  6. 46 CFR 128.230 - Penetrations of hulls and watertight bulkheads-materials and pressure design.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Penetrations of hulls and watertight bulkheads-materials and pressure design. 128.230 Section 128.230 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... § 128.230 Penetrations of hulls and watertight bulkheads—materials and pressure design. (a) Each...

  7. Designing Web-Based Educative Curriculum Materials for the Social Studies

    ERIC Educational Resources Information Center

    Callahan, Cory; Saye, John; Brush, Thomas

    2013-01-01

    This paper reports on a design experiment of web-based curriculum materials explicitly created to help social studies teachers develop their professional teaching knowledge. Web-based social studies curriculum reform efforts, human-centered interface design, and investigations into educative curriculum materials are reviewed, as well as…

  8. 46 CFR 160.156-23 - Procedure for approval of design, material, or construction change.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Boats and Fast Rescue Boats (SOLAS) § 160.156-23 Procedure for approval of design, material, or construction change. (a) Each change in design, material, or construction from the plans approved under 46 CFR... approved under 46 CFR 159.005-13 and § 160.156-13(h) of this subpart need not be resubmitted. (b)...

  9. 46 CFR 160.156-23 - Procedure for approval of design, material, or construction change.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Boats and Fast Rescue Boats (SOLAS) § 160.156-23 Procedure for approval of design, material, or construction change. (a) Each change in design, material, or construction from the plans approved under 46 CFR... approved under 46 CFR 159.005-13 and § 160.156-13(h) of this subpart need not be resubmitted. (b)...

  10. 46 CFR 160.156-23 - Procedure for approval of design, material, or construction change.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Boats and Fast Rescue Boats (SOLAS) § 160.156-23 Procedure for approval of design, material, or construction change. (a) Each change in design, material, or construction from the plans approved under 46 CFR... approved under 46 CFR 159.005-13 and § 160.156-13(h) of this subpart need not be resubmitted. (b)...

  11. 78 FR 37759 - Ocean Dumping; Atchafalaya-West Ocean Dredged Material Disposal Site Designation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-24

    ...: Comments. The comment period for the proposed rule and draft EIS published May 21, 2013 (78 FR 29687), is... AGENCY 40 CFR Part 228 Ocean Dumping; Atchafalaya-West Ocean Dredged Material Disposal Site Designation... designate the Atchafalaya-West Ocean Dredged Material Disposal Site pursuant to the draft EIS,...

  12. 46 CFR 128.220 - Class II non-vital systems-materials and pressure design.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Class II non-vital systems-materials and pressure design. 128.220 Section 128.220 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS MARINE ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.220 Class...

  13. A Tutorial Design Process Applied to an Introductory Materials Engineering Course

    ERIC Educational Resources Information Center

    Rosenblatt, Rebecca; Heckler, Andrew F.; Flores, Katharine

    2013-01-01

    We apply a "tutorial design process", which has proven to be successful for a number of physics topics, to design curricular materials or "tutorials" aimed at improving student understanding of important concepts in a university-level introductory materials science and engineering course. The process involves the identification…

  14. Digital Alchemy for Materials Design: Colloids and Beyond.

    PubMed

    van Anders, Greg; Klotsa, Daphne; Karas, Andrew S; Dodd, Paul M; Glotzer, Sharon C

    2015-10-27

    Starting with the early alchemists, a holy grail of science has been to make desired materials by modifying the attributes of basic building blocks. Building blocks that show promise for assembling new complex materials can be synthesized at the nanoscale with attributes that would astonish the ancient alchemists in their versatility. However, this versatility means that making a direct connection between building-block attributes and bulk structure is both necessary for rationally engineering materials and difficult because building block attributes can be altered in many ways. Here we show how to exploit the malleability of the valence of colloidal nanoparticle "elements" to directly and quantitatively link building-block attributes to bulk structure through a statistical thermodynamic framework we term "digital alchemy". We use this framework to optimize building blocks for a given target structure and to determine which building-block attributes are most important to control for self-assembly, through a set of novel thermodynamic response functions, moduli, and susceptibilities. We thereby establish direct links between the attributes of colloidal building blocks and the bulk structures they form. Moreover, our results give concrete solutions to the more general conceptual challenge of optimizing emergent behaviors in nature and can be applied to other types of matter. As examples, we apply digital alchemy to systems of truncated tetrahedra, rhombic dodecahedra, and isotropically interacting spheres that self-assemble diamond, fcc, and icosahedral quasicrystal structures, respectively. Although our focus is on colloidal systems, our methods generalize to any building blocks with adjustable interactions. PMID:26401754

  15. Digital Alchemy for Materials Design: Colloids and Beyond

    NASA Astrophysics Data System (ADS)

    van Anders, Greg; Klotsa, Daphne; Karas, Andrew; Dodd, Paul; Glotzer, Sharon

    Starting with the early alchemists, a holy grail of science has been to make desired materials by manipulating basic building blocks. Building blocks that show promise for assembling new complex materials can be synthesized at the nanoscale with attributes that would astonish the ancient alchemists in their versatility. However, this versatility means that connecting building-block attributes to bulk structure is both necessary for rationally engineering materials and difficult because building block attributes can be altered in many ways. We show how to exploit the malleability of colloidal nanoparticle ``elements'' to quantitatively link building-block attributes to bulk structure through a statistical thermodynamic framework we term ``digital alchemy''. We use this framework to optimize building blocks for a given target structure and to determine which building-block attributes are most important to control for self-assembly, through a set of novel thermodynamic response functions. We thereby establish direct links between the attributes of colloidal building blocks and the bulk structures they form. Moreover, our results give concrete solutions to the more general conceptual challenge of optimizing emergent behaviors in nature and can be applied to other types of matter.

  16. First Materials Science Research Facility Rack Capabilities and Design Features

    NASA Technical Reports Server (NTRS)

    Cobb, S.; Higgins, D.; Kitchens, L.; Curreri, Peter (Technical Monitor)

    2002-01-01

    The first Materials Science Research Rack (MSRR-1) is the primary facility for U.S. sponsored materials science research on the International Space Station. MSRR-1 is contained in an International Standard Payload Rack (ISPR) equipped with the Active Rack Isolation System (ARIS) for the best possible microgravity environment. MSRR-1 will accommodate dual Experiment Modules and provide simultaneous on-orbit processing operations capability. The first Experiment Module for the MSRR-1, the Materials Science Laboratory (MSL), is an international cooperative activity between NASA's Marshall Space Flight Center (MSFC) and the European Space Agency's (ESA) European Space Research and Technology Center (ESTEC). The MSL Experiment Module will accommodate several on-orbit exchangeable experiment-specific Module Inserts which provide distinct thermal processing capabilities. Module Inserts currently planned for the MSL are a Quench Module Insert, Low Gradient Furnace, and a Solidification with Quench Furnace. The second Experiment Module for the MSRR-1 configuration is a commercial device supplied by MSFC's Space Products Development (SPD) Group. Transparent furnace assemblies include capabilities for vapor transport processes and annealing of glass fiber preforms. This Experiment Module is replaceable on-orbit. This paper will describe facility capabilities, schedule to flight and research opportunities.

  17. A Computational Method for Materials Design of Interfaces

    NASA Astrophysics Data System (ADS)

    Kaminski, Jakub; Ratsch, Christian; Shankar, Sadasivan

    2014-03-01

    In the present work we propose a novel computational approach to explore the broad configurational space of possible interfaces formed from known crystal structures to find new hetrostructure materials with potentially interesting properties. In the series of subsequent steps with increasing complexity and accuracy, the vast number of possible combinations is narrowed down to a limited set of the most promising and chemically compatible candidates. This systematic screening encompasses (i) establishing the geometrical compatibility along multiple crystallographic orientations of two (or more) materials, (ii) simple functions eliminating configurations with unfavorable interatomic steric conflicts, (iii) application of empirical and semi-empirical potentials estimating approximate energetics and structures, (iv) use of DFT based quantum-chemical methods to ascertain the final optimal geometry and stability of the interface in question. We also demonstrate the flexibility and efficiency of our approach depending on the size of the investigated structures and size of the search space. The representative results from our search protocol will be presented for selected materials including semiconductors, transition metal systems, and oxides.

  18. Materials technology assessment for a 1050 K Stirling space engine design

    NASA Technical Reports Server (NTRS)

    Scheuermann, Coulson M.; Dreshfield, Robert L.; Gaydosh, Darrell J.; Kiser, James D.; Mackay, Rebecca A.; Mcdaniels, David L.; Petrasek, Donald W.; Vannucci, Raymond D.; Bowles, Kenneth J.; Watson, Gordon K.

    1988-01-01

    An assessment of materials technology and proposed materials selection was made for the 1050 K (superalloy) Stirling Space Engine design. The objectives of this assessment were to evaluate previously proposed materials selections, evaluate the current state-of-the-art materials, propose potential alternate materials selections and identify research and development efforts needed to provide materials that can meet the stringent system requirements. This assessment generally reaffirmed the choices made by the contractor. However, in many cases alternative choices were described and suggestions for needed materials and fabrication research and development were made.

  19. Materials technology assessment for a 1050 K Stirling Space Engine design

    SciTech Connect

    Scheuermann, C.M.; Dreshfield, R.L.; Gaydosh, D.J.; Kiser, J.D.; MacKay, R.A.; McDanels, D.L.; Petrasek, D.W.; Vannucci, R.D.; Bowles, K.J.; Watson, G.K.

    1988-10-01

    An assessment of materials technology and proposed materials selection was made for the 1050 K (superalloy) Stirling Space Engine design. The objectives of this assessment were to evaluate previously proposed materials selections, evaluate the current state-of-the-art materials, propose potential alternate materials selections and identify research and development efforts needed to provide materials that can meet the stringent system requirements. This assessment generally reaffirmed the choices made by the contractor; however, in many cases alternative choices were described and suggestions for needed materials and fabrication research and development were made.

  20. Design elements for the development of cancer education print materials for a Latina/o audience.

    PubMed

    Buki, Lydia P; Salazar, Silvia I; Pitton, Viviana O

    2009-10-01

    Health educators can help reduce cancer disparities in Latino populations through the creation of effective print materials. In this effort, the National Cancer Institute conducted a comprehensive needs assessment to identify key design elements of cancer education programs and create a cost-effective process that would ensure consistency in the development of materials. This article introduces the Checklist of Design Elements for the Development of Cancer Education Print Materials for Latina/o Audiences (CEMLA), which includes a total of 10 design elements related to the process of developing materials and content. Using social learning theory as a theoretical framework, design elements are included that reflect cultural sensitivity at the surface and deep structure levels. This is the most comprehensive effort to date to integrate and synthesize theory and application in the design of materials for this audience. PMID:19098265

  1. Design of responsive materials using topologically interlocked elements

    NASA Astrophysics Data System (ADS)

    Molotnikov, A.; Gerbrand, R.; Qi, Y.; Simon, G. P.; Estrin, Y.

    2015-02-01

    In this work we present a novel approach to designing responsive structures by segmentation of monolithic plates into an assembly of topologically interlocked building blocks. The particular example considered is an assembly of interlocking osteomorphic blocks. The results of this study demonstrate that the constraining force, which is required to hold the blocks together, can be viewed as a design parameter that governs the bending stiffness and the load bearing capacity of the segmented structure. In the case where the constraining forces are provided laterally using an external frame, the maximum load the assembly can sustain and its stiffness increase linearly with the magnitude of the lateral load applied. Furthermore, we show that the segmented plate with integrated shape memory wires employed as tensioning cables can act as a smart structure that changes its flexural stiffness and load bearing capacity in response to external stimuli, such as heat generated by the switching on and off an electric current.

  2. Virtual Welded - Joint Design Integrating Advanced Materials and Processing Technology

    SciTech Connect

    Yang, Zhishang; Ludewig, Howard W.; Babu, S. Suresh

    2005-06-30

    Virtual Welede-Joint Design, a systematic modeling approach, has been developed in this project to predict the relationship of welding process, microstructure, properties, residual stress, and the ultimate weld fatique strength. This systematic modeling approach was applied in the welding of high strength steel. A special welding wire was developed in this project to introduce compressive residual stress at weld toe. The results from both modeling and experiments demonstrated that more than 10x fatique life improvement can be acheived in high strength steel welds by the combination of compressive residual stress from the special welding wire and the desired weld bead shape from a unique welding process. The results indicate a technology breakthrough in the design of lightweight and high fatique performance welded structures using high strength steels.

  3. 78 FR 38672 - Ocean Dumping; Sabine-Neches Waterway (SNWW) Ocean Dredged Material Disposal Site Designation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-27

    ...The EPA is proposing to designate four new Ocean Dredged Material Disposal Site(s) (ODMDS) located offshore of Texas for the disposal of dredged material from the Sabine-Neches Waterway (SNWW), pursuant to the Marine Protection, Research and Sanctuaries Act, as amended (MPRSA). The new sites are needed for the disposal of additional dredged material associated with the SNWW Channel Improvement......

  4. Elementary Students' Learning of Materials Science Practices through Instruction Based on Engineering Design Tasks

    ERIC Educational Resources Information Center

    Wendell, Kristen Bethke; Lee, Hee-Sun

    2010-01-01

    Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline within the study of matter. This paper examines how third grade students' materials science performance changes over the course of instruction based on an engineering design challenge. We conducted a case study of nine…

  5. Materials design and processings for industrial high-strain-rate superplastic forming

    SciTech Connect

    Hosokawa, H.; Higashi, K.

    2000-07-01

    The optimum materials design in microstructural control could be developed for the high-strain-rate superplastic materials in the industrial scale. In the present work, it is reported that the high-performance-engine pistons with near-net-shape can be fabricated by the superplastic forging technology in the high-strain-rate superplastic PM Al-Si based alloy, which is produced by using this optimum materials design.

  6. Decoupling interrelated parameters for designing high performance thermoelectric materials.

    PubMed

    Xiao, Chong; Li, Zhou; Li, Kun; Huang, Pengcheng; Xie, Yi

    2014-04-15

    The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for

  7. Photovoltaic Module Encapsulation Design and Materials Selection, Volume 1, Abridged

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.

    1982-01-01

    A summary version of Volume 1, presenting the basic encapsulation systems, their purposes and requirements, and the characteristics of the most promising candidate systems and materials, as identified and evaluated by the Flat-Plate Solar Array Project is presented. In this summary version considerable detail and much supporting and experimental information has necessarily been omitted. A reader interested in references and literature citations, and in more detailed information on specific topics, should consult Reference 1, JPL Document No. 5101-177, JPL Publication 81-102, DOE/JPL-1012-60 (JPL), June 1, 1982.

  8. Experimental design and theoretical analysis on the proof experiment of the inverse Doppler effect at optical frequencies

    NASA Astrophysics Data System (ADS)

    Jiang, Qiang; Liang, Binming; Hu, Aiqing

    2013-08-01

    The proof experiment of inverse Doppler effect is simulated by idealizing optical field distribution of laser as fundamental mode Gaussian beam. Two key factors, the detecting area and the angle from light to normal of detecting surface, are analyzed. The proof experiment conducted recently by our research team successfully shows that the experimental data are consistent with theoretical data. Our work lays a solid foundation for the design of experimental system and the coming experiments on the mechanism of inverse Doppler effect in negative index materials.

  9. Rational Design of Molecular Ferroelectric Materials and Nanostructures

    SciTech Connect

    Ducharme, Stephen

    2012-09-25

    The purpose of this project was to gain insight into the properties of molecular ferroelectrics through the detailed study of oligomer analogs of polyvinylidene fluoride (PVDF). By focusing on interactions at both the molecular level and the nanoscale level, we expect to gain improved understanding about the fundamental mechanism of ferroelectricity and its key properties. The research consisted of three complementary components: 1) Rational synthesis of VDF oligomers by Prof. Takacs' group; 2) Detailed structural and electrical studies of thin by Prof. Ducharme's Group; and 3) First-principles computational studies by DOE Lab Partner Dr. Serge Nakhman-son at Argonne National Laboratory. The main results of the work was a detailed understanding of the relationships between the molecular interactions and macroscopic phenomenology of fer-roelectricity VDF oligomers. This is valuable information supporting the development of im-proved electromechanical materials for, e.g., sonar, ultrasonic imaging, artificial muscles, and compliant actuators. Other potential applications include nonvolatile ferroelectric memories, heat-sensing imaging arrays, photovoltaic devices, and functional biomimetic materials. The pro-ject contributed to the training and professional development of undergraduate students and graduate students, post-doctoral assistants, and a high-school teacher. Project personnel took part in several outreach and education activities each year.

  10. Resolution of the Band Gap Prediction Problem for Materials Design.

    PubMed

    Crowley, Jason M; Tahir-Kheli, Jamil; Goddard, William A

    2016-04-01

    An important property with any new material is the band gap. Standard density functional theory methods grossly underestimate band gaps. This is known as the band gap problem. Here, we show that the hybrid B3PW91 density functional returns band gaps with a mean absolute deviation (MAD) from experiment of 0.22 eV over 64 insulators with gaps spanning a factor of 500 from 0.014 to 7 eV. The MAD is 0.28 eV over 70 compounds with gaps up to 14.2 eV, with a mean error of -0.03 eV. To benchmark the quality of the hybrid method, we compared the hybrid method to the rigorous GW many-body perturbation theory method. Surprisingly, the MAD for B3PW91 is about 1.5 times smaller than the MAD for GW. Furthermore, B3PW91 is 3-4 orders of magnitude faster computationally. Hence, B3PW91 is a practical tool for predicting band gaps of materials before they are synthesized and represents a solution to the band gap prediction problem. PMID:26944092

  11. Robotic Materials Handling in Space: Mechanical Design of the Robot Operated Materials Processing System HitchHiker Experiment

    NASA Technical Reports Server (NTRS)

    Voellmer, George

    1997-01-01

    The Goddard Space Flight Center has developed the Robot Operated Materials Processing System (ROMPS) that flew aboard STS-64 in September, 1994. The ROMPS robot transported pallets containing wafers of different materials from their storage racks to a furnace for thermal processing. A system of tapered guides and compliant springs was designed to deal with the potential misalignments. The robot and all the sample pallets were locked down for launch and landing. The design of the passive lockdown system, and the interplay between it and the alignment system are presented.

  12. Designing nacre-like materials for simultaneous stiffness, strength and toughness: Optimum materials, composition, microstructure and size

    NASA Astrophysics Data System (ADS)

    Barthelat, Francois

    2014-12-01

    Nacre, bone and spider silk are staggered composites where inclusions of high aspect ratio reinforce a softer matrix. Such staggered composites have emerged through natural selection as the best configuration to produce stiffness, strength and toughness simultaneously. As a result, these remarkable materials are increasingly serving as model for synthetic composites with unusual and attractive performance. While several models have been developed to predict basic properties for biological and bio-inspired staggered composites, the designer is still left to struggle with finding optimum parameters. Unresolved issues include choosing optimum properties for inclusions and matrix, and resolving the contradictory effects of certain design variables. Here we overcome these difficulties with a multi-objective optimization for simultaneous high stiffness, strength and energy absorption in staggered composites. Our optimization scheme includes material properties for inclusions and matrix as design variables. This process reveals new guidelines, for example the staggered microstructure is only advantageous if the tablets are at least five times stronger than the interfaces, and only if high volume concentrations of tablets are used. We finally compile the results into a step-by-step optimization procedure which can be applied for the design of any type of high-performance staggered composite and at any length scale. The procedure produces optimum designs which are consistent with the materials and microstructure of natural nacre, confirming that this natural material is indeed optimized for mechanical performance.

  13. Molecular Designs for Enhancement of Polarity in Ferroelectric Soft Materials

    NASA Astrophysics Data System (ADS)

    Ohtani, Ryo; Nakaya, Manabu; Ohmagari, Hitomi; Nakamura, Masaaki; Ohta, Kazuchika; Lindoy, Leonard F.; Hayami, Shinya

    2015-11-01

    The racemic oxovanadium(IV) salmmen complexes, [VO((rac)-(4-X-salmmen))] (X = C12C10C5 (1), C16 (2), and C18 (3); salmmen = N,N‧-monomethylenebis-salicylideneimine) with “banana shaped” molecular structures were synthesized, and their ferroelectric properties were investigated. These complexes exhibit well-defined hysteresis loops in their viscous phases, moreover, 1 also displays liquid crystal behaviour. We observed a synergetic effect influenced by three structural aspects; the methyl substituents on the ethylene backbone, the banana shaped structure and the square pyramidal metal cores all play an important role in generating the observed ferroelectricity, pointing the way to a useful strategy for the creation of advanced ferroelectric soft materials.

  14. First principles materials design of novel functional oxides

    NASA Astrophysics Data System (ADS)

    Cooper, Valentino R.; Voas, Brian K.; Bridges, Craig A.; Morris, James R.; Beckman, Scott P.

    2016-05-01

    We review our efforts to develop and implement robust computational approaches for exploring phase stability to facilitate the prediction-to-synthesis process of novel functional oxides. These efforts focus on a synergy between (i) electronic structure calculations for properties predictions, (ii) phenomenological/empirical methods for examining phase stability as related to both phase segregation and temperature-dependent transitions and (iii) experimental validation through synthesis and characterization. We illustrate this philosophy by examining an inaugural study that seeks to discover novel functional oxides with high piezoelectric responses. Our results show progress towards developing a framework through which solid solutions can be studied to predict materials with enhanced properties that can be synthesized and remain active under device relevant conditions.

  15. Molecular Designs for Enhancement of Polarity in Ferroelectric Soft Materials

    PubMed Central

    Ohtani, Ryo; Nakaya, Manabu; Ohmagari, Hitomi; Nakamura, Masaaki; Ohta, Kazuchika; Lindoy, Leonard F.; Hayami, Shinya

    2015-01-01

    The racemic oxovanadium(IV) salmmen complexes, [VO((rac)-(4-X-salmmen))] (X = C12C10C5 (1), C16 (2), and C18 (3); salmmen = N,N′-monomethylenebis-salicylideneimine) with “banana shaped” molecular structures were synthesized, and their ferroelectric properties were investigated. These complexes exhibit well-defined hysteresis loops in their viscous phases, moreover, 1 also displays liquid crystal behaviour. We observed a synergetic effect influenced by three structural aspects; the methyl substituents on the ethylene backbone, the banana shaped structure and the square pyramidal metal cores all play an important role in generating the observed ferroelectricity, pointing the way to a useful strategy for the creation of advanced ferroelectric soft materials. PMID:26568045

  16. Materials design of ceramic-based layer structures for crowns.

    PubMed

    Lawn, B R; Deng, Y; Lloyd, I K; Janal, M N; Rekow, E D; Thompson, V P

    2002-06-01

    Radial cracking has been identified as the primary mode of failure in all-ceramic crowns. This study investigates the hypothesis that critical loads for radial cracking in crown-like layers vary explicitly as the square of ceramic layer thickness. Experimental data from tests with spherical indenters on model flat laminates of selected dental ceramics bonded to clear polycarbonate bases (simulating crown/dentin structures) are presented. Damage initiation events are video-recorded in situ during applied loading, and critical loads are measured. The results demonstrate an increase in the resistance to radial cracking for zirconia relative to alumina and for alumina relative to porcelain. The study provides simple a priori predictions of failure in prospective ceramic/substrate bilayers and ranks ceramic materials for best clinical performance. PMID:12097438

  17. First principles materials design of novel functional oxides

    DOE PAGESBeta

    Cooper, Valentino R.; Voas, Brian K.; Bridges, Craig A.; Morris, James R.; Beckman, Scott P.

    2016-05-31

    We review our efforts to develop and implement robust computational approaches for exploring phase stability to facilitate the prediction-to-synthesis process of novel functional oxides. These efforts focus on a synergy between (i) electronic structure calculations for properties predictions, (ii) phenomenological/empirical methods for examining phase stability as related to both phase segregation and temperature-dependent transitions and (iii) experimental validation through synthesis and characterization. We illustrate this philosophy by examining an inaugural study that seeks to discover novel functional oxides with high piezoelectric responses. Lastly, our results show progress towards developing a framework through which solid solutions can be studied to predictmore » materials with enhanced properties that can be synthesized and remain active under device relevant conditions.« less

  18. Computational design of materials for solar hydrogen generation

    NASA Astrophysics Data System (ADS)

    Umezawa, Naoto

    Photocatalysis has a great potential for the production of hydrogen from aquerous solution under solar light. In this talk, two different approaches toward the computational materials desing for solar hydrogen generation will be presented. Tin (Sn), which has two major oxidation states, Sn2+ and Sn4+, is abundant on the earth's crust. Recently, visible-light responsive photocatalytc H2 evolution reaction was identified over a mixed valence tin oxide Sn3O4. We have carried out crystal structure prediction for mixed valence tin oxides in different atomic compositions under ambient pressure condition using advanced computational methods based on the evolutionary crystal-structure search and density-functional theory. The predicted novel crystal structures realize the desirable band gaps and band edge positions for H2 evolution under visible light irradiation. It is concluded that multivalent tin oxides have a great potential as an abundant, cheap and environmentally-benign solar-energy conversion photofunctional materials. Transition metal doping is effective for sensitizing SrTiO3 under visible light. We have theoretically investigated the roles of the doped Cr in STO based on hybrid density-functional calculations. Cr atoms are preferably substituting for Ti under any equilibrium growth conditions. The lower oxidation state Cr3+, which is stabilized under an n-type condition of STO, is found to be advantageous for the photocatalytic performance. It is firther predicted that lanthanum is the best codopant for stabilizing the favorable oxidation state, Cr3+. The prediction was validated by our experiments that La and Cr co-doped STO shows the best performance among examined samples. This work was supported by the Japan Science and Technology Agency (JST) Precursory Research for Embryonic Science and Technology (PRESTO) and International Research Fellow program of Japan Society for the Promotion of Science (JSPS) through project P14207.

  19. Master's Degree Learners' Use of Theory in Designing Instructional Materials

    ERIC Educational Resources Information Center

    Wojtecki, John A.

    2012-01-01

    Educational institutions offering a master's degree program in instructional design incorporate instructional design theory into the master's degree course offerings. The responsibility for the student is to develop coursework. Master's degree learners will use instructional design theory to develop course materials. This study…

  20. Materials Design and Discovery with High-Throughput Density Functional Theory: The Open Quantum Materials Database (OQMD)

    NASA Astrophysics Data System (ADS)

    Saal, James E.; Kirklin, Scott; Aykol, Muratahan; Meredig, Bryce; Wolverton, C.

    2013-11-01

    High-throughput density functional theory (HT DFT) is fast becoming a powerful tool for accelerating materials design and discovery by the amassing tens and even hundreds of thousands of DFT calculations in large databases. Complex materials problems can be approached much more efficiently and broadly through the sheer quantity of structures and chemistries available in such databases. Our HT DFT database, the Open Quantum Materials Database (OQMD), contains over 200,000 DFT calculated crystal structures and will be freely available for public use at http://oqmd.org. In this review, we describe the OQMD and its use in five materials problems, spanning a wide range of applications and materials types: (I) Li-air battery combination catalyst/electrodes, (II) Li-ion battery anodes, (III) Li-ion battery cathode coatings reactive with HF, (IV) Mg-alloy long-period stacking ordered (LPSO) strengthening precipitates, and (V) training a machine learning model to predict new stable ternary compounds.

  1. An advanced microcomputer design for processing of semiconductor materials

    NASA Technical Reports Server (NTRS)

    Bjoern, L.; Lindkvist, L.; Zaar, J.

    1988-01-01

    In the Get Away Special 330 payload two germanium samples doped with gallium will be processed. The aim of the experiments is to create a planar solid/liquid interface, and to study the breakdown of this interface as the crystal growth rate increases. For the experiments a gradient furnace was designed which is heated by resistive heaters. Cooling is provided by circulating gas from the atmosphere in the cannister through cooling channels in the furnace. The temperature along the sample are measured by platinum/rhodium thermocouples. The furnace is controlled by a microcomputer system, based upon the processor 80C88. A data acquisition system is integrated into the system. In order to synchronize the different actions in time, a multitask manager is used.

  2. Ionomer Design Principles for Single Ion-Conducting Energy Materials

    NASA Astrophysics Data System (ADS)

    Colby, Ralph; Liang, Siwei; Liu, Wenjuan; Hyeok Choi, U.; Runt, James; Shiau, Huai-Suen; Janik, Michael

    2012-02-01

    Single-ion conducting ionomers with low glass transition temperature, high dielectric constant and containing bulky ions with diffuse charge, are needed for polymer membranes that transport small counterions. Overarching design principles emerging from quantum chemistry calculations suggest that diffuse charge can be attained from simple considerations of atomic electronegativity. For lithium or sodium batteries, perfluorinated tetraphenyl borate ionomers with solvating polar comonomers are proposed. For fluoride or hydroxide batteries and for iodide transporting solar cells, tetra-alkyl phosphonium ionomers with anion receptors are proposed. First attempts to construct such ionomers to test these ideas will be discussed, with results from dielectric spectroscopy to measure conductivity, dielectric constant and number density of simultaneously conducting ions.

  3. Material property for designing, analyzing, and fabricating space structures

    NASA Technical Reports Server (NTRS)

    Kolkailah, Faysal A.

    1991-01-01

    An analytical study was made of plasma assisted bullet projectile. The finite element analysis and the micro-macromechanic analysis was applied to an optimum design technique for the multilayered graphite-epoxy composite projectile that will achieve hypervelocity of 6 to 10 Km/s. The feasibility was determined of dialectics to monitor cure of graphite-epoxies. Several panels were fabricated, cured, and tested with encouraging results of monitoring the cure of graphite-epoxies. The optimum cure process for large structures was determined. Different orientation were used and three different curing cycles were employed. A uniaxial tensile test was performed on all specimens. The optimum orientation with the optimum cure cycle were concluded.

  4. Computational Design of Photovoltaic Materials with Self Organized Nano Structures

    NASA Astrophysics Data System (ADS)

    Sato, Kazunori; Katayama-Yoshida, Hiroshi

    2013-03-01

    Chalcopyrite and II-VI semiconductors, such as Cu(In, Ga)Se2, Cu2ZnSn(S, Se)4 and Cd(S, Te), are one of the most promising materials for low cost photovoltaic solar-cells. In this paper, based on first-principles calculations, we propose that self-organized nano-structures in these compounds will enhance the conversion efficiency. Our calculations are based on the KKR-CPA-LDA with the self-interaction correction. We also use VASP package for calculating mixing energy and effective interactions of the systems by using the cluster expansion method. For phase separating systems, we simulate nano-structure formation by using the Monte Carlo method. It is expected that the photo-generated electron-hole pairs are efficiently separated by the type-II interface and then effectively transferred along the quasi-one-dimensional structures. Moreover, we can expect multiplication of generated carriers due to the multi-exciton effects in nano-structures.

  5. Life Modeling and Design Analysis for Ceramic Matrix Composite Materials

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The primary research efforts focused on characterizing and modeling static failure, environmental durability, and creep-rupture behavior of two classes of ceramic matrix composites (CMC), silicon carbide fibers in a silicon carbide matrix (SiC/SiC) and carbon fibers in a silicon carbide matrix (C/SiC). An engineering life prediction model (Probabilistic Residual Strength model) has been developed specifically for CMCs. The model uses residual strength as the damage metric for evaluating remaining life and is posed probabilistically in order to account for the stochastic nature of the material s response. In support of the modeling effort, extensive testing of C/SiC in partial pressures of oxygen has been performed. This includes creep testing, tensile testing, half life and residual tensile strength testing. C/SiC is proposed for airframe and propulsion applications in advanced reusable launch vehicles. Figures 1 and 2 illustrate the models predictive capabilities as well as the manner in which experimental tests are being selected in such a manner as to ensure sufficient data is available to aid in model validation.

  6. Materials modeling by design: applications to amorphous solids

    NASA Astrophysics Data System (ADS)

    Biswas, Parthapratim; Tafen, D. N.; Inam, F.; Cai, Bin; Drabold, D. A.

    2009-02-01

    In this paper, we review a host of methods used to model amorphous materials. We particularly describe methods which impose constraints on the models to ensure that the final model meets a priori requirements (on structure, topology, chemical order, etc). In particular, we review work based on quench from the melt simulations, the 'decorate and relax' method, which is shown to be a reliable scheme for forming models of certain binary glasses. A 'building block' approach is also suggested and yields a pleading model for GeSe1.5. We also report on the nature of vulcanization in an Se network cross-linked by As, and indicate how introducing H into an a-Si network develops into a-Si:H. We also discuss explicitly constrained methods including reverse Monte Carlo (RMC) and a novel method called 'Experimentally Constrained Molecular Relaxation'. The latter merges the power of ab initio simulation with the ability to impose external information associated with RMC.

  7. Materials modeling by design: applications to amorphous solids.

    PubMed

    Biswas, Parthapratim; Tafen, D N; Inam, F; Cai, Bin; Drabold, D A

    2009-02-25

    In this paper, we review a host of methods used to model amorphous materials. We particularly describe methods which impose constraints on the models to ensure that the final model meets a priori requirements (on structure, topology, chemical order, etc). In particular, we review work based on quench from the melt simulations, the 'decorate and relax' method, which is shown to be a reliable scheme for forming models of certain binary glasses. A 'building block' approach is also suggested and yields a pleading model for GeSe(1.5). We also report on the nature of vulcanization in an Se network cross-linked by As, and indicate how introducing H into an a-Si network develops into a-Si:H. We also discuss explicitly constrained methods including reverse Monte Carlo (RMC) and a novel method called 'Experimentally Constrained Molecular Relaxation'. The latter merges the power of ab initio simulation with the ability to impose external information associated with RMC. PMID:21817359

  8. Effects of Buckling Knockdown Factor, Internal Pressure and Material on the Design of Stiffened Cylinders

    NASA Technical Reports Server (NTRS)

    Lovejoy, Andrew E.; Hilburger, Mark W.; Chunchu, Prasad B.

    2010-01-01

    A design study was conducted to investigate the effect shell buckling knockdown factor (SBKF), internal pressure and aluminum alloy material selection on the structural weight of stiffened cylindrical shells. Two structural optimization codes were used for the design study to determine the optimum minimum-weight design for a series of design cases, and included an in-house developed genetic algorithm (GA) code and PANDA2. Each design case specified a unique set of geometry, material, knockdown factor combinations and loads. The resulting designs were examined and compared to determine the effects of SBKF, internal pressure and material selection on the acreage design weight and controlling failure mode. This design study shows that use of less conservative SBKF values, including internal pressure, and proper selection of material alloy can result in significant weight savings for stiffened cylinders. In particular, buckling-critical cylinders with integrally machined stiffener construction can benefit from the use of thicker plate material that enables taller stiffeners, even when the stiffness, strength and density properties of these materials appear to be inferior.

  9. Accelerated materials design of fast oxygen ionic conductors based on first principles calculations

    NASA Astrophysics Data System (ADS)

    He, Xingfeng; Mo, Yifei

    Over the past decades, significant research efforts have been dedicated to seeking fast oxygen ion conductor materials, which have important technological applications in electrochemical devices such as solid oxide fuel cells, oxygen separation membranes, and sensors. Recently, Na0.5Bi0.5TiO3 (NBT) was reported as a new family of fast oxygen ionic conductor. We will present our first principles computation study aims to understand the O diffusion mechanisms in the NBT material and to design this material with enhanced oxygen ionic conductivity. Using the NBT materials as an example, we demonstrate the computation capability to evaluate the phase stability, chemical stability, and ionic diffusion of the ionic conductor materials. We reveal the effects of local atomistic configurations and dopants on oxygen diffusion and identify the intrinsic limiting factors in increasing the ionic conductivity of the NBT materials. Novel doping strategies were predicted and demonstrated by the first principles calculations. In particular, the K doped NBT compound achieved good phase stability and an order of magnitude increase in oxygen ionic conductivity of up to 0.1 S cm-1 at 900 K compared to the experimental Mg doped compositions. Our results provide new avenues for the future design of the NBT materials and demonstrate the accelerated design of new ionic conductor materials based on first principles techniques. This computation methodology and workflow can be applied to the materials design of any (e.g. Li +, Na +) fast ion-conducting materials.

  10. Structural materials for ITER in-vessel component design

    NASA Astrophysics Data System (ADS)

    Kalinin, G.; Gauster, W.; Matera, R.; Tavassoli, A.-A. F.; Rowcliffe, A.; Fabritsiev, S.; Kawamura, H.

    1996-10-01

    The materials proposed for ITER in-vessel components have to exhibit adequate performance for the operating lifetime of the reactor or for specified replacement intervals. Estimates show that maximum irradiation dose to be up to 5-7 dpa (for 1 MWa/m 2 in the basic performance phase (BPP)) within a temperature range from 20 to 300°C. Austenitic SS 316LN-ITER Grade was defined as a reference option for the vacuum vessel, blanket, primary wall, pipe lines and divertor body. Conventional technologies and mill products are proposed for blanket, back plate and manifold manufacturing. HIPing is proposed as a reference manufacturing method for the primary wall and blanket and as an option for the divertor body. The existing data show that mechanical properties of HIPed SS are no worse than those of forged 316LN SS. Irradiation will result in property changes. Minimum ductility has been observed after irradiation in an approximate temperature range between 250 and 350°C, for doses of 5-10 dpa. In spite of radiation-induced changes in tensile deformation behavior, the fracture remains ductile. Irradiation assisted corrosion cracking is a concern for high doses of irradiation and at high temperatures. Re-welding is one of the critical issues because of the need to replace failed components. It is also being considered for the replacement of shielding blanket modules by breeding modules after the BPP. Estimates of radiation damage at the locations for re-welding show that the dose will not exceed 0.05 dpa (with He generation of 1 appm) for the manifold and 0.01 dpa (with He generation 0.1 appm) for the back plate for the BPP of ITER operation. Existing experimental data show that these levels will not result in property changes for SS; however, neutron irradiation and He generation promote crack formation in the heat affected zone during welding. Cu based alloys, DS-Cu (Glidcop A125) and PHCu CuCrZr bronze) are proposed as a structural materials for high heat flux

  11. Materials study supporting thermochemical hydrogen cycle sulfuric acid decomposer design

    NASA Astrophysics Data System (ADS)

    Peck, Michael S.

    Increasing global climate change has been driven by greenhouse gases emissions originating from the combustion of fossil fuels. Clean burning hydrogen has the potential to replace much of the fossil fuels used today reducing the amount of greenhouse gases released into the atmosphere. The sulfur iodine and hybrid sulfur thermochemical cycles coupled with high temperature heat from advanced nuclear reactors have shown promise for economical large-scale hydrogen fuel stock production. Both of these cycles employ a step to decompose sulfuric acid to sulfur dioxide. This decomposition step occurs at high temperatures in the range of 825°C to 926°C dependent on the catalysis used. Successful commercial implementation of these technologies is dependent upon the development of suitable materials for use in the highly corrosive environments created by the decomposition products. Boron treated diamond film was a potential candidate for use in decomposer process equipment based on earlier studies concluding good oxidation resistance at elevated temperatures. However, little information was available relating the interactions of diamond and diamond films with sulfuric acid at temperatures greater than 350°C. A laboratory scale sulfuric acid decomposer simulator was constructed at the Nuclear Science and Engineering Institute at the University of Missouri-Columbia. The simulator was capable of producing the temperatures and corrosive environments that process equipment would be exposed to for industrialization of the sulfur iodide or hybrid sulfur thermochemical cycles. A series of boron treated synthetic diamonds were tested in the simulator to determine corrosion resistances and suitability for use in thermochemical process equipment. These studies were performed at twenty four hour durations at temperatures between 600°C to 926°C. Other materials, including natural diamond, synthetic diamond treated with titanium, silicon carbide, quartz, aluminum nitride, and Inconel

  12. Ranking the stars: a refined Pareto approach to computational materials design.

    PubMed

    Lejaeghere, Kurt; Cottenier, Stefaan; Van Speybroeck, Veronique

    2013-08-16

    We propose a procedure to rank the most interesting solutions from high-throughput materials design studies. Such a tool is becoming indispensable due to the growing size of computational screening studies and the large number of criteria involved in realistic materials design. As a proof of principle, the binary tungsten alloys are screened for both large-weight and high-impact materials, as well as for fusion reactor applications. Moreover, the concept is generally applicable to any design problem where multiple competing criteria have to be optimized. PMID:23992074

  13. Soft materials design via self assembly of functionalized icosahedral particles

    NASA Astrophysics Data System (ADS)

    Muthukumar, Vidyalakshmi Chockalingam

    In this work we simulate self assembly of icosahedral building blocks using a coarse grained model of the icosahedral capsid of virus 1m1c. With significant advancements in site-directed functionalization of these macromolecules [1], we propose possible application of such self-assembled materials for drug delivery. While there have been some reports on organization of viral particles in solution through functionalization, exploiting this behaviour for obtaining well-ordered stoichiometric structures has not yet been explored. Our work is in well agreement with the earlier simulation studies of icosahedral gold nanocrystals, giving chain like patterns [5] and also broadly in agreement with the wet lab works of Finn, M.G. et al., who have shown small predominantly chain-like aggregates with mannose-decorated Cowpea Mosaic Virus (CPMV) [22] and small two dimensional aggregates with oligonucleotide functionalization on the CPMV capsid [1]. To quantify the results of our Coarse Grained Molecular Dynamics Simulations I developed analysis routines in MATLAB using which we found the most preferable nearest neighbour distances (from the radial distribution function (RDF) calculations) for different lengths of the functional groups and under different implicit solvent conditions, and the most frequent coordination number for a virus particle (histogram plots further using the information from RDF). Visual inspection suggests that our results most likely span the low temperature limits explored in the works of Finn, M.G. et al., and show a good degree of agreement with the experimental results in [1] at an annealing temperature of 4°C. Our work also reveals the possibility of novel stoichiometric N-mer type aggregates which could be synthesized using these capsids with appropriate functionalization and solvent conditions.

  14. Research Update: Towards designed functionalities in oxide-based electronic materials

    SciTech Connect

    Rondinelli, James M.; Poeppelmeier, Kenneth R.; Zunger, Alex

    2015-08-01

    One of the grand challenges facing materials-by-design approaches for complex oxide deployment in electronic devices is how to balance transformative first-principles based predictions with experimental feasibility. Here, we briefly review the functionality-driven approach (inverse design) for materials discovery, encapsulated in three modalities for materials discovery (m{sup 3}D) that integrate experimental feedback. We compare it to both traditional theoretical and high-throughput database-directed approaches aimed at advancing oxide-based materials into technologies.

  15. EDITORIAL: Photonic materials on demand Photonic materials on demand

    NASA Astrophysics Data System (ADS)

    Zheludev, Nikolay; Padilla, Willie J.; Brener, Igal

    2012-11-01

    As David Payne famously said, 'we never have a photonic material that we want...'. This has changed with the proliferation of nanotechnology. Metamaterials—artificial media structured on a sub-wavelength scale—offer a radical paradigm for the engineering of optical properties. Some remarkable advances have been possible with metamaterials. These include, for instance, negative-index media that refract light in the opposite direction from that of conventional materials, chiral materials that rotate the polarization state of light hundreds of thousands of times more strongly than natural optical crystals, and structured thin films with remarkably strong dispersion that can slow light in much the same way as resonant atomic systems with electromagnetically induced transparency. The research agenda is now shifting towards achieving tunable and switchable functionalities with metamaterials [1] where the goal is, paraphrasing Dave Payne, 'to have on demand the photonic material that we want'. The papers in this Journal of Optics special issue explore and review the different approaches to both switching and tuning of metamaterial properties through exploiting effects such as phase conjugation, intense photo-excitation and photoconductivity, the use of electro-optical effects in conductive oxides, the exploitation global quantum coherency and resonantly coupled classical resonator and quantum structures, hybridization with gain media and the manipulation with shapes and constitution of the complex metamolecules and metamaterial reliefs by design, or using MEMS actuation. References [1] Zheludev N I and Kivshar Y 2012 From metamaterials to metadevices Nature Mater.11 917

  16. The Role of Engineering Design in Materials Science and Engineering Curricula

    NASA Astrophysics Data System (ADS)

    Allen, Emily

    2008-03-01

    Undergraduate materials engineering curricula diverge from materials science curricula in two important ways. An underlying requirement is to prepare the graduates for industrial positions, so they need a good grounding in processing and statistical methods, as well as a strong set of hands-on skills in materials characterization and metrology. The other distinguishing feature of an engineering education is the focus on design rather than research. In the case of materials science and engineering, the design deliverable is often a process design, a materials selection, or a failure analysis. Some of the features of education for design include the exercise of thinking about the customer's needs, functional requirements of the product, the cost of production, and the broader context of the design project in society. These ideas can be integrated or at least introduced early in the curriculum and in many different types of courses. Materials Science and Engineering programs have the dual requirement of educating both future scientists and future engineers. Graduating baccalaureate students need to be ready for engineering practice, yet many also are being readied for graduate study and research. One aspect of this ambiguity is that research and design activities are not always as clearly differentiated as they are in other engineering programs. How can one undergraduate curriculum be successful at both? One key distinguishing element in engineering practice is engineering design. Design activities occur in many aspects of the profession and may be practiced by both scientists and engineers; however it is engineering curricula, not science curricula, that tend to explicitly focus on developing the skills and methods of design practice in students. Accredited programs within colleges of engineering are required to emphasize engineering practice and design, while still providing the necessary conceptual development of the underlying science. Current practices and

  17. Perspective: NanoMine: A material genome approach for polymer nanocomposites analysis and design

    NASA Astrophysics Data System (ADS)

    Zhao, He; Li, Xiaolin; Zhang, Yichi; Schadler, Linda S.; Chen, Wei; Brinson, L. Catherine

    2016-05-01

    Polymer nanocomposites are a designer class of materials where nanoscale particles, functional chemistry, and polymer resin combine to provide materials with unprecedented combinations of physical properties. In this paper, we introduce NanoMine, a data-driven web-based platform for analysis and design of polymer nanocomposite systems under the material genome concept. This open data resource strives to curate experimental and computational data on nanocomposite processing, structure, and properties, as well as to provide analysis and modeling tools that leverage curated data for material property prediction and design. With a continuously expanding dataset and toolkit, NanoMine encourages community feedback and input to construct a sustainable infrastructure that benefits nanocomposite material research and development.

  18. Development of Digital Materials Database for Design and Construction of New Power Plants

    SciTech Connect

    Ren, Weiju

    2008-01-01

    To facilitate materials selection, structural design, and future maintenance of the Generation IV nuclear reactor systems, an interactive, internet accessible materials property database, dubbed Gen IV Materials Handbook, has been under development with the support of the United States Department of Energy. The Handbook will provide an authoritative source of information on structural materials needed for the development of various Gen IV nuclear reactor systems along with powerful data analysis and management tools. In this paper, the background, history, framework, major features, contents, and development strategy of the Gen IV Materials Handbook are discussed. Current development status and future plans are also elucidated.

  19. Computational nano-materials design of high efficiency photovoltaic materials by spinodal nano-decomposition in Chalcopyrite-type semiconductors

    NASA Astrophysics Data System (ADS)

    Asahina, Hideo; Tani, Yoshimasa; Sato, Kazunori; Katayama-Yoshida, Hiroshi

    2014-03-01

    Chalcopyrite-type semiconductor CuInSe2 (CIS) is one of the most promising materials for low cost photovoltaic solar-cells due to its self-regeneration mechanism. However, from the point of resource security, high concentration of In in CIS is serious disadvantage. Recently, Cu2ZnSnS4 (CZTS) attracts much attention to overcome this disadvantage of CIS. This material has already been investigated as a photovoltaic material but the efficiency is not high enough. Based on the first-principles calculations by the KKR-CPA method, we propose how we can enhance the efficiency of CZTS by utilizing the self-organization phenomena caused by spinodal nano-decomposition of Cu & Cu-vacancy, S & Se, and Se & Oxygen. We will compare our design with the available experimental data of STEM-EDX, EELS, Atom Probe Tomography and Raman Scattering data. In addition to the above materials design, we also discuss intermediate band type solar-cells caused by the spinodal nano-decomposition, and propose Fe-doped CuFeS2-CuAlS2 (CFS-CAS), CuFeS2-CuGaS2 (CFS-CGS) and CuFeS2-CuInS2 (CFS-CIS) as promising materials with enhanced conversion efficiency up to 50%.

  20. Dedication to Degradation: The Beauty of Materials Designed to Lay in Ruin

    NASA Astrophysics Data System (ADS)

    Nychka, John A.; Kruzic, Jaime

    2014-04-01

    Degradation of materials is typically perceived to be a negative response in service. Many designs, and materials, have been and are ruined due to corrosion, fatigue, weathering, ultraviolet light, fungal attack, bacterial attack, erosion, wear, electromigration… and on the list goes. However, the carefully controlled and purposeful degradation of materials is a prerequisite for success for some designs—and such ability is a beautiful necessity when it comes to many regenerative biomaterials. In other instances, we must seek first to understand the degradation mechanisms before we can achieve degradation prevention—and the resistance of some materials to degradation is also beautiful. Regardless of whether we try to prevent or elicit degradation, our dedication to degradation of materials is ever present in materials design.

  1. Design finalization and material qualification towards procurement of the ITER vacuum vessel

    NASA Astrophysics Data System (ADS)

    Ioki, K.; Barabash, V.; Bachmann, C.; Chappuis, P.; Choi, C. H.; Cordier, J.-J.; Giraud, B.; Gribov, Y.; Heitzenroeder, Ph.; Her, N.; Johnson, G.; Jones, L.; Jun, C.; Kim, B. C.; Kuzmin, E.; Loesser, D.; Martin, A.; Merola, M.; Pathak, H.; Readman, P.; Sugihara, M.; Terasawa, A.; Utin, Yu.; Wang, X.; Wu, S.; Yu, J.; ITER Organization; ITER Parties

    2011-10-01

    Procurement arrangements for ITER key components including the vacuum vessel (VV) have been signed and the ITER activities are now fully devoted towards construction. Final design reviews have been carried out for the main vessel and ports. One of the design review topics is the selection of materials, material procurement, and assessment of material performance during operation. The width of the inner shell splice plates was increased from 120 mm to 160 mm to minimize risk during the assembly of the Thermal shields and the VV. Instead of facet shaping, 3D shaping was introduced for the outboard inner shell. The material qualification procedures have been started for VV structural materials such as 316L(N) IG for licensing as a nuclear pressure equipment component. In accordance with the regulatory requirements and quality requirements for operation, common material specifications have been prepared in collaboration with the domestic agencies.

  2. Curriculum Design for Inquiry: Preservice Elementary Teachers' Mobilization and Adaptation of Science Curriculum Materials

    ERIC Educational Resources Information Center

    Forbes, Cory T.; Davis, Elizabeth A.

    2010-01-01

    Curriculum materials are crucial tools with which teachers engage students in science as inquiry. In order to use curriculum materials effectively, however, teachers must develop a robust capacity for pedagogical design, or the ability to mobilize a variety of personal and curricular resources to promote student learning. The purpose of this study…

  3. 46 CFR 160.077-7 - Procedure for approval of design or material revision.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Procedure for approval of design or material revision. 160.077-7 Section 160.077-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Hybrid...

  4. Learning to Design and Analyze Materials Handling Systems: Developing Multimedia Tools

    ERIC Educational Resources Information Center

    Heragu, Sunderesh; Jennings, Sybillyn

    2003-01-01

    In this paper, we describe aspects related to learning and learning assessment including pedagogy, cognition, pilot study and results from the study. This study is conducted for an educational module on "10 Principles of Materials Handling". This module along with another on "Analysis and Design of Integrated Materials Handling Systems" constitute…

  5. An Annotated Bibliography of Materials Designed and Organized for Adult Use in Discussion Groups.

    ERIC Educational Resources Information Center

    Ellison, John W.

    This first annotated bibliography of materials designed and organized for adult use in disucssion groups includes both book and nonbook material. Areas dealt with are: art, censorship, change, child guidance, communication, crime, democracy, economics, education, evolution, food, foreign affairs, forgetting, generation gap, gold, good and evil,…

  6. 46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Hydraulic or pneumatic power and control-materials and... Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component (such as pipe runs, fittings, flanges, and standard valves) for hydraulic or pneumatic power and...

  7. 75 FR 19311 - Ocean Dumping; Guam Ocean Dredged Material Disposal Site Designation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ...The EPA is proposing to designate the Guam Deep Ocean Disposal Site (G-DODS) as a permanent ocean dredged material disposal site (ODMDS) located offshore of Guam. Dredging is essential for maintaining safe navigation at port and naval facilities in Apra Harbor and other locations around Guam. Not all dredged materials are suitable for beneficial re-use (e.g., construction materials, landfill......

  8. Materials design considerations and selection for a large rad waste incinerator

    SciTech Connect

    Vormelker, P.R.; Jenkins, C.F.; Burns, H.H.

    1997-01-01

    A new incinerator has been built to process self-generated, low level radioactive wastes at the Department of Energy`s Savannah River Site. Wastes include protective clothing and other solid materials used during the handling of radioactive materials, and liquid chemical wastes resulting from chemical and waste management operations. The basic design and materials of construction selected to solve the anticipated corrosion problems from hot acidic gases are reviewed. Problems surfacing during trial runs prior to radioactive operations are discussed.

  9. 30 CFR 27.20 - Quality of material, workmanship, and design.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Quality of material, workmanship, and design. 27.20 Section 27.20 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS METHANE-MONITORING SYSTEMS Construction and Design Requirements § 27.20 Quality of...

  10. Solid state photochemistry. Subpanel A-2(a): Design of molecular precursors for electronic materials

    SciTech Connect

    Wells, R.L.

    1996-09-01

    Recent achievements of synthetic chemistry in the field of electronic materials are presented in three categories; viz, precursor design for improved processing, new chemistry for selective growth, and new growth techniques. This is followed by a discussion of challenges and opportunities in two general areas designated as composition and structure, and growth and processing.

  11. Representing Clarity: Using Universal Design Principles to Create Effective Hybrid Course Learning Materials

    ERIC Educational Resources Information Center

    Spiegel, Cheri Lemieux

    2012-01-01

    This article describes how the author applied principles of universal design to hybrid course materials to increase student understanding and, ultimately, success. Pulling the three principles of universal design--consistency, color, and icon representation--into the author's Blackboard course allowed her to change the types of reading skills…

  12. The synergistic effects of slip ring-brush design and materials

    NASA Technical Reports Server (NTRS)

    Lewis, N. E.; Cole, S. R.; Glossbrenner, E. W.

    1974-01-01

    The design, fabrication, and subsequent testing of four power slip rings for synchronous orbit application are described. The synergistic effects of contact materials and slip ring-brush design are studied by means of frequent and simultaneous recording of friction, wear, and electrical noise. Data generated during the test period are presented along with post test analysis data.

  13. 14 CFR 29.613 - Material strength properties and design values.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Material strength properties and...

  14. 14 CFR 27.613 - Material strength properties and design values.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Material strength properties and...

  15. 14 CFR 29.613 - Material strength properties and design values.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Material strength properties and...

  16. 14 CFR 29.613 - Material strength properties and design values.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Material strength properties and...

  17. 14 CFR 27.613 - Material strength properties and design values.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Material strength properties and...

  18. 14 CFR 27.613 - Material strength properties and design values.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Material strength properties and...

  19. 14 CFR 29.613 - Material strength properties and design values.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Material strength properties and...

  20. 14 CFR 27.613 - Material strength properties and design values.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Material strength properties and...

  1. 14 CFR 29.613 - Material strength properties and design values.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Material strength properties and...

  2. 14 CFR 27.613 - Material strength properties and design values.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... probability with 95 percent confidence. (c) The strength, detail design, and fabrication of the structure must... the actual strength properties of that particular item will equal or exceed those used in design... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Material strength properties and...

  3. 30 CFR 27.20 - Quality of material, workmanship, and design.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Quality of material, workmanship, and design. 27.20 Section 27.20 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS METHANE-MONITORING SYSTEMS Construction and Design Requirements § 27.20 Quality of...

  4. Computational nano-material design of exotic luminescent materials based upon europium doped gallium nitrides

    NASA Astrophysics Data System (ADS)

    Masago, Akira; Fukushima, Tetsuya; Sato, Kazunori; Katayama-Yoshida, Hiroshi

    2015-03-01

    Eu-doped GaN has attracted much attention, because the red light luminescence ability provides us with expectations to realize monolithic full-color LEDs, which work on seamless conditions such as substrates, electrodes, and operating bias voltages. Toward implementation of multifunctional activity into the luminescent materials using the spinodal nano-structures, we investigate atomic configurations and magnetic structures of the GaN crystal codoped with Eu, Mg, Si, O, and/or the vacancies using the density functional method (DFT) calculations. Our calculations show that the impurity clusterized distributions are energetically favorable more than the homogeneous distribution. Moreover, analyses of the formation energy and binding energy suggest that the clusterized distributions are spontaneously formed by the nano-spinodal decomposition. Though the host matrix has no magnetic moments, the cluster has finite magnetic moments, where Zener's p-f exchange interaction works between the Eu f-state and the nearby N p-states.

  5. James C. McGroddy Prize for New Materials Talk: From discovery to design of new materials

    NASA Astrophysics Data System (ADS)

    Kanatzidis, Mercouri G.

    The design and discovery of new materials and their crystal growth is critical for continued scientific and technological progress far into the future. It is also a fundamental goal of condense matter science. We have been developing the chemistry of novel chalcogenide and intermetallic materials which define a remarkably broad set of structurally diverse compounds, associated with a wide range of physical properties and impacting a variety of physics and materials science issues. In contrast to solid-state methods, materials syntheses in liquid fluxes permit crystallization at lower temperatures due to facile diffusion and possible chemical reactions with the flux itself. These reactions can produce a wide range of materials, often metastable such as oxides, chalcogenides and intermetallics, but typically the formation paths are obscure or poorly understood. In this talk I will describe how we observe, understand, and engineer the formation of compounds from inorganic melts and an approach we call ``panoramic synthesis''. I will also highlight some of our recent results on the discovery of remarkable materials and crystal structures and how they can be leveraged for achieving unusual or enhanced properties of interest in a variety of fields such as thermoelectrics, γ ray detection, superconductivity, topological properties, nonlinear optics, etc.

  6. First wall and blanket module safety enhancement by material selection and design decision

    SciTech Connect

    Merrill, B.J.

    1980-01-01

    A thermal/mechanical study has been performed which illustrates the behavior of a fusion reactor first wall and blanket module during a loss of coolant flow event. The relative safety advantages of various material and design options were determined. A generalized first wall-blanket concept was developed to provide the flexibility to vary the structural material (stainless steel vs titanium), coolant (helium vs water), and breeder material (liquid lithium vs solid lithium aluminate). In addition, independent vs common first wall-blanket cooling and coupled adjacent module cooling design options were included in the study. The comparative analyses were performed using a modified thermal analysis code to handle phase change problems.

  7. Study of materials for the design of MEMS capacitive pressure sensor

    NASA Astrophysics Data System (ADS)

    Jindal, Sumit Kumar; Raghuwanshi, Sanjeev Kumar

    2016-04-01

    Highly sensitive MEMS capacitive pressure sensor is nowadays used for many different applications such as aerospace, automobile, Bio-MEMS etc. This paper deals with study and comparison of different types of materials that can be used in design of MEMS capacitive pressure sensor. Initially principle and design of basic MEMS capacitive pressure sensor is explained. In the next section the properties of different materials is elaborated. The centre deflection of the diaphragm is calculated using COMSOL Multiphysics and Capacitance is calculated using MATLAB simulation. From the capacitance calculated sensitivity of the materials can be interpreted. The analysis is carried out for a pressure range of 0 to 0.1 MPa.

  8. Effects of Materials Parameters and Design Details on the Fatigue of Composite Materials for Wind Turbine Blades

    SciTech Connect

    Mandell, J.F.; Samborsky, D.D.; Sutherland, H.J.

    1999-03-04

    This paper presents an analysis of the results of nine years of fatigue testing represented in the USDOE/Montana State University (DOE/MSU) Composite Materials Fatigue Database. The focus of the program has been to explore a broad range of glass-fiber-based materials parameters encompassing over 4500 data points for 130 materials systems. Significant trends and transitions in fatigue resistance are shown as the fiber content and fabric architecture are varied. The effects of structural details including ply drops, bonded stiffeners, and other geometries that produce local variations in fiber packing and geometry are also described. Fatigue tests on composite beam structures are then discussed; these show generally good correlation with coupon fatigue data in the database. Goodman diagrams for fatigue design are presented, and their application to predicting the service lifetime of blades is described.

  9. Directed Self Assembly (DSA) compliant flow with immersion lithography: from material to design and patterning

    NASA Astrophysics Data System (ADS)

    Ma, Yuansheng; Wang, Yan; Word, James; Lei, Junjiang; Mitra, Joydeep; Torres, J. Andres; Hong, Le; Fenger, Germain; Khaira, Daman; Preil, Moshe; Yuan, Lei; Kye, Jongwook; Levinson, Harry J.

    2016-03-01

    In this paper, we present a DSA compliant flow for contact/via layers with immersion lithography assuming the grapho-epitaxy process for cylinders' formation. We demonstrate that the DSA technology enablement needs co-optimization among material, design, and lithography. We show that the number of DSA grouping constructs is countable for the gridded-design architecture. We use Template Error Enhancement Factor (TEEF) to choose DSA material, determine grouping design rules, and select the optimum guiding patterns. Our post-pxOPC imaging data shows that it is promising to achieve 2-mask solution with DSA for the contact/via layer using 193i at 5nm node.

  10. Application of the ASME code in designing containment vessels for packages used to transport radioactive materials

    SciTech Connect

    Raske, D.T.; Wang, Z.

    1992-07-01

    The primary concern governing the design of shipping packages containing radioactive materials is public safety during transport. When these shipments are within the regulatory jurisdiction of the US Department of Energy, the recommended design criterion for the primary containment vessel is either Section III or Section VIII, Division 1, of the ASME Boiler and Pressure Vessel Code, depending on the activity of the contents. The objective of this paper is to discuss the design of a prototypic containment vessel representative of a packaging for the transport of high-level radioactive material.

  11. Materials, Processes and Manufacturing in Ares 1 Upper Stage: Integration with Systems Design and Development

    NASA Technical Reports Server (NTRS)

    Bhat, Biliyar N.

    2008-01-01

    Ares I Crew Launch Vehicle Upper Stage is designed and developed based on sound systems engineering principles. Systems Engineering starts with Concept of Operations and Mission requirements, which in turn determine the launch system architecture and its performance requirements. The Ares I-Upper Stage is designed and developed to meet these requirements. Designers depend on the support from materials, processes and manufacturing during the design, development and verification of subsystems and components. The requirements relative to reliability, safety, operability and availability are also dependent on materials availability, characterization, process maturation and vendor support. This paper discusses the roles and responsibilities of materials and manufacturing engineering during the various phases of Ares IUS development, including design and analysis, hardware development, test and verification. Emphasis is placed how materials, processes and manufacturing support is integrated over the Upper Stage Project, both horizontally and vertically. In addition, the paper describes the approach used to ensure compliance with materials, processes, and manufacturing requirements during the project cycle, with focus on hardware systems design and development.

  12. Multiphysics design optimization model for structural walls incorporating phase-change materials

    NASA Astrophysics Data System (ADS)

    Stockwell, A.; Neithalath, N.; Rajan, S. D.

    2015-03-01

    The development of energy-efficient building envelopes has been an ongoing effort in many countries owing to the pressing need to achieve energy independence. In this study numerical optimization techniques and finite element analysis provide the means to find a compromise point between adding phase-change materials (PCMs) to a concrete wall, the energy savings and the wall's structural capacity. The primary objective is to minimize the overall lifetime cost of a wall by understanding the implications of PCM layer thickness, material properties and position in the wall on the overall energy consumption. While it is difficult to manually configure a typical wall for the lowest total cost, the developed computational framework provides an automated tool for searching for the best design. The results show that successful designs can be obtained where material and energy costs can be minimized through a judicious combination of existing building materials with thermal energy storage materials.

  13. Manufacturing process and material selection in concurrent collaborative design of MEMS devices

    NASA Astrophysics Data System (ADS)

    Zha, Xuan F.; Du, H.

    2003-09-01

    In this paper we present knowledge of an intensive approach and system for selecting suitable manufacturing processes and materials for microelectromechanical systems (MEMS) devices in concurrent collaborative design environment. In the paper, fundamental issues on MEMS manufacturing process and material selection such as concurrent design framework, manufacturing process and material hierarchies, and selection strategy are first addressed. Then, a fuzzy decision support scheme for a multi-criteria decision-making problem is proposed for estimating, ranking and selecting possible manufacturing processes, materials and their combinations. A Web-based prototype advisory system for the MEMS manufacturing process and material selection, WebMEMS-MASS, is developed based on the client-knowledge server architecture and framework to help the designer find good processes and materials for MEMS devices. The system, as one of the important parts of an advanced simulation and modeling tool for MEMS design, is a concept level process and material selection tool, which can be used as a standalone application or a Java applet via the Web. The running sessions of the system are inter-linked with webpages of tutorials and reference pages to explain the facets, fabrication processes and material choices, and calculations and reasoning in selection are performed using process capability and material property data from a remote Web-based database and interactive knowledge base that can be maintained and updated via the Internet. The use of the developed system including operation scenario, use support, and integration with an MEMS collaborative design system is presented. Finally, an illustration example is provided.

  14. The Halogen Bond in the Design of Functional Supramolecular Materials: Recent Advances

    PubMed Central

    2013-01-01

    Halogen bonding is an emerging noncovalent interaction for constructing supramolecular assemblies. Though similar to the more familiar hydrogen bonding, four primary differences between these two interactions make halogen bonding a unique tool for molecular recognition and the design of functional materials. First, halogen bonds tend to be much more directional than (single) hydrogen bonds. Second, the interaction strength scales with the polarizability of the bond-donor atom, a feature that researchers can tune through single-atom mutation. In addition, halogen bonds are hydrophobic whereas hydrogen bonds are hydrophilic. Lastly, the size of the bond-donor atom (halogen) is significantly larger than hydrogen. As a result, halogen bonding provides supramolecular chemists with design tools that cannot be easily met with other types of noncovalent interactions and opens up unprecedented possibilities in the design of smart functional materials. This Account highlights the recent advances in the design of halogen-bond-based functional materials. Each of the unique features of halogen bonding, directionality, tunable interaction strength, hydrophobicity, and large donor atom size, makes a difference. Taking advantage of the hydrophobicity, researchers have designed small-size ion transporters. The large halogen atom size provided a platform for constructing all-organic light-emitting crystals that efficiently generate triplet electrons and have a high phosphorescence quantum yield. The tunable interaction strengths provide tools for understanding light-induced macroscopic motions in photoresponsive azobenzene-containing polymers, and the directionality renders halogen bonding useful in the design on functional supramolecular liquid crystals and gel-phase materials. Although halogen bond based functional materials design is still in its infancy, we foresee a bright future for this field. We expect that materials designed based on halogen bonding could lead to

  15. Multiobjective control design including performance robustness for gust alleviation of a wing with adaptive material actuators

    NASA Astrophysics Data System (ADS)

    Layton, Jeffrey B.

    1997-06-01

    The goal of this paper is to examine the use of covariance control to directly design reduced-order multi-objective controllers for gust alleviation using adaptive materials as the control effector. It will use piezoelectric actuators as control effectors in a finite element model of a full-size wing model. More precisely, the finite element model is of the F-16 Agile Falcon/Active Flexible Wing that is modified to use piezoelectric actuators as control effectors. The paper will also examine the interacting roles of important control design constraints and objectives for designing an aeroservoelastic system. The paper will also present some results of multiobjective control design for the model, illustrating the benefits and complexity of modern practical control design for aeroservoelastic systems that use adaptive materials for actuation.

  16. Elementary Students' Learning of Materials Science Practices Through Instruction Based on Engineering Design Tasks

    NASA Astrophysics Data System (ADS)

    Wendell, Kristen Bethke; Lee, Hee-Sun

    2010-12-01

    Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline within the study of matter. This paper examines how third grade students' materials science performance changes over the course of instruction based on an engineering design challenge. We conducted a case study of nine students who participated in engineering design-based science instruction with the goal of constructing a stable, quiet, thermally comfortable model house. The learning outcome of materials science practices was assessed by clinical interviews conducted before and after the instruction, and the learning process was assessed by students' workbooks completed during the instruction. The interviews included two materials selection tasks for designing a sturdy stepstool and an insulated pet habitat. Results indicate that: (1) students significantly improved on both materials selection tasks, (2) their gains were significantly positively associated with the degree of completion of their workbooks, and (3) students who were highly engaged with the workbook's reflective record-keeping tasks showed the greatest improvement on the interviews. These findings suggest the important role workbooks can play in facilitating elementary students' learning of science through authentic activity such as engineering design.

  17. Microwave Nondestructive Evaluation of Dielectric Materials with a Metamaterial Lens

    NASA Technical Reports Server (NTRS)

    Shreiber, Daniel; Gupta, Mool; Cravey, Robin L.

    2008-01-01

    A novel microwave Nondestructive Evaluation (NDE) sensor was developed in an attempt to increase the sensitivity of the microwave NDE method for detection of defects small relative to a wavelength. The sensor was designed on the basis of a negative index material (NIM) lens. Characterization of the lens was performed to determine its resonant frequency, index of refraction, focus spot size, and optimal focusing length (for proper sample location). A sub-wavelength spot size (3 dB) of 0.48 lambda was obtained. The proof of concept for the sensor was achieved when a fiberglass sample with a 3 mm diameter through hole (perpendicular to the propagation direction of the wave) was tested. The hole was successfully detected with an 8.2 cm wavelength electromagnetic wave. This method is able to detect a defect that is 0.037 lambda. This method has certain advantages over other far field and near field microwave NDE methods currently in use.

  18. Analysis of the requirements on modern energetics and their impact on materials design

    NASA Astrophysics Data System (ADS)

    Foster, Joseph C., Jr.; Glumac, Nick; Stewart, D. Scott

    2012-03-01

    We characterized the "design" of explosive materials as represented by the complete suite of engineering specifications on ingredients and processes used in the manufacture of specific components used in various applications. The detonation of explosive materials and the associated high power density of this process have historically been accepted as essential elements of the design. Evolving requirements such as the desire for insensitive munitions and the broadened demands of controlling the power output are producing a new class on energetic materials whose thermo-chemical response to specific intentional trigger mechanisms result in reactive behavior far removed the classical detonation modeling represented by the physics and chemistry of Chapman-Jouguet [CJ] or Zel'dovich, VonNeuman, Doering [ZND] detonation models. Experimental studies of representative designs and analysis of the role of processes controlled by the mesostructure suggest functional paths to establishing the desired output.

  19. Analysis of the Requirements on Modern Energetics and Their Impact on Materials Design

    NASA Astrophysics Data System (ADS)

    Foster, Joseph C., Jr.; Glumac, Nick; Stewart, D. Scott

    2011-06-01

    We have characterized the ``design'' of explosive materials as represented by the complete suite of engineering specifications on ingredients and processes used in the manufacture of specific components used in various application. The detonation of explosive materials and the associated high power density of this process has historically been an essential element of the design. Evolving requirements such as the desire for insensitive munitions and broadened demands on the control of the power output are producing a new class on energetic materials whose thermo-chemical response to specific intentional trigger mechanisms result in reactive behavior far removed the classical detonation modeling represented by the physics and chemistry of Chapman-Jouguet [CJ] or Zel'dovich, VonNeuman, Doering [ZND] detonation model. Experimental studies of representative designs and analysis of the role of processes controlled by the mesostructure suggest functional paths to establishing the desired output.

  20. Designing and Developing Online Materials for Molecular Biology: Building Online Programs for Science

    PubMed Central

    Boulay, Rachel

    2013-01-01

    A well-accepted form of educational training offered in molecular biology is internships in research laboratories. However, the number of available research laboratories severely limits access by most students. Addressing this need, the University of Hawaii launched a project to expand this model to include newly developed online training materials in addition to a hands-on laboratory experience. This paper explores the design and development process of the online learning materials. This case study looks at the roles of the instructional designer, multimedia specialist, and research faculty who were the subject matter experts. The experiences of the design teams are shared in an effort to gain insight on how the collaborative efforts of the project group led to a successful deployment of the online learning materials. PMID:24319699

  1. Rational Design of Diketopyrrolopyrrole-Based Small Molecules as Donating Materials for Organic Solar Cells

    PubMed Central

    Jin, Ruifa; Wang, Kai

    2015-01-01

    A series of diketopyrrolopyrrole-based small molecules have been designed to explore their optical, electronic, and charge transport properties as organic solar cell (OSCs) materials. The calculation results showed that the designed molecules can lower the band gap and extend the absorption spectrum towards longer wavelengths. The designed molecules own the large longest wavelength of absorption spectra, the oscillator strength, and absorption region values. The optical, electronic, and charge transport properties of the designed molecules are affected by the introduction of different π-bridges and end groups. We have also predicted the mobility of the designed molecule with the lowest total energies. Our results reveal that the designed molecules are expected to be promising candidates for OSC materials. Additionally, the designed molecules are expected to be promising candidates for electron and/or hole transport materials. On the basis of our results, we suggest that molecules under investigation are suitable donors for [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and its derivatives as acceptors of OSCs. PMID:26343640

  2. Rational Design of Diketopyrrolopyrrole-Based Small Moleculesas Donating Materials for Organic Solar Cells.

    PubMed

    Jin, Ruifa; Wang, Kai

    2015-01-01

    A series of diketopyrrolopyrrole-based small molecules have been designed to explore their optical, electronic, and charge transport properties as organic solar cell(OSCs) materials. The calculation results showed that the designed molecules can lower the band gap and extend the absorption spectrum towards longer wavelengths.The designed molecules own the large longest wavelength of absorption spectra,the oscillator strength, and absorption region values. The optical, electronic, and charge transport properties of the designed molecules are affected by the introduction of different π-bridges and end groups. We have also predicted the mobility of the designed molecule with the lowest total energies. Our results reveal that the designed molecules are expected to be promising candidates for OSC materials. Additionally, the designed molecules are expected to be promising candidates for electron and/or hole transport materials. On the basis of our results, we suggest that molecules under investigation are suitable donors for[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and its derivatives as acceptors of OSCs. PMID:26343640

  3. Bioactive ceramic-based materials with designed reactivity for bone tissue regeneration

    PubMed Central

    Ohtsuki, Chikara; Kamitakahara, Masanobu; Miyazaki, Toshiki

    2009-01-01

    Bioactive ceramics have been used clinically to repair bone defects owing to their biological affinity to living bone; i.e. the capability of direct bonding to living bone, their so-called bioactivity. However, currently available bioactive ceramics do not satisfy every clinical application. Therefore, the development of novel design of bioactive materials is necessary. Bioactive ceramics show osteoconduction by formation of biologically active bone-like apatite through chemical reaction of the ceramic surface with surrounding body fluid. Hence, the control of their chemical reactivity in body fluid is essential to developing novel bioactive materials as well as biodegradable materials. This paper reviews novel bioactive materials designed based on chemical reactivity in body fluid. PMID:19158015

  4. Data mining for materials design: A computational study of single molecule magnet

    NASA Astrophysics Data System (ADS)

    Dam, Hieu Chi; Pham, Tien Lam; Ho, Tu Bao; Nguyen, Anh Tuan; Nguyen, Viet Cuong

    2014-01-01

    We develop a method that combines data mining and first principles calculation to guide the designing of distorted cubane Mn4 +Mn^{3+}_3 single molecule magnets. The essential idea of the method is a process consisting of sparse regressions and cross-validation for analyzing calculated data of the materials. The method allows us to demonstrate that the exchange coupling between Mn4 + and Mn3 + ions can be predicted from the electronegativities of constituent ligands and the structural features of the molecule by a linear regression model with high accuracy. The relations between the structural features and magnetic properties of the materials are quantitatively and consistently evaluated and presented by a graph. We also discuss the properties of the materials and guide the material design basing on the obtained results.

  5. Data mining for materials design: A computational study of single molecule magnet

    SciTech Connect

    Dam, Hieu Chi; Pham, Tien Lam; Ho, Tu Bao; Nguyen, Anh Tuan; Nguyen, Viet Cuong

    2014-01-28

    We develop a method that combines data mining and first principles calculation to guide the designing of distorted cubane Mn{sup 4+} Mn {sub 3}{sup 3+} single molecule magnets. The essential idea of the method is a process consisting of sparse regressions and cross-validation for analyzing calculated data of the materials. The method allows us to demonstrate that the exchange coupling between Mn{sup 4+} and Mn{sup 3+} ions can be predicted from the electronegativities of constituent ligands and the structural features of the molecule by a linear regression model with high accuracy. The relations between the structural features and magnetic properties of the materials are quantitatively and consistently evaluated and presented by a graph. We also discuss the properties of the materials and guide the material design basing on the obtained results.

  6. Materials and mechanical design analysis of boron carbide reactor safety rods. Final report

    SciTech Connect

    Marra, J.C.

    1992-04-01

    The purpose of this task was to analyze the materials and mechanical design bases for the new boron carbide safety rod. These analyses included examination of the irradiation response of the materials, chemical compatibility of component materials, moisture considerations for the boron carbide pellets and susceptibility of the rod to corrosion under reactor environmental conditions. A number of issues concerning the mechanical behavior were also addressed. These included: safety rod dynamic response in scram scenarios, flexibility and mishandling behavior, and response to thermal excursions associated with gamma heating. A surveillance program aimed at evaluating the integrity of the safety rods following actual operating conditions and justifying life extension for the rods was also proposed. Based on the experimental testing and analyses associated with this task, it is concluded that the boron carbide safety rod design meets the materials and mechanical criteria for successful operational performance.

  7. Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies

    SciTech Connect

    Yang, Z.; Dong, P.; Liu, S.; Babu, S.; Olson, G.; DebRoy, T.

    2005-04-15

    The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce

  8. Materials and design experience in a slurry-fed electric glass melter

    SciTech Connect

    Barnes, S.M.; Larson, D.E.

    1981-08-01

    The design of a slurry-fed electric gas melter and an examination of the performance and condition of the construction materials were completed. The joule-heated, ceramic-lined melter was constructed to test the applicability of materials and processes for high-level waste vitrification. The developmental Liquid-Fed Ceramic Melter (LFCM) was operated for three years with simulated high-level waste and was subjected to conditions more severe than those expected for a nuclear waste vitrification plant.

  9. Sustainable manufacturing: Effect of material selection and design on the environmental impact in the manufacturing process

    NASA Astrophysics Data System (ADS)

    Hazwan Syafiq Harun, Mohd; Taha, Zahari; Salaam, Hadi Abdul

    2013-12-01

    The environmental impact of a manufacturing process is also dependent on the selection of the material and design of a product. This is because the manufacturing of a product is directly connected to the amount of carbon emitted in consuming the electrical energy for that manufacturing process. The difference in the general properties of materials such as strength, hardness and impact will have significant effect on the power consumption of the machine used to complete the product. In addition the environmental impact can also be reduced if the proposed designs use less material. In this study, an LCA tool called Eco-It is used. Evaluate the environmental impact caused by manufacturing simple jig. A simple jig with 4 parts was used as a case study. Two experiments were carried out. The first experiment was to study the environmental effects of different material, and the second experiment was to study the environmental impact of different design. The materials used for the jig are Aluminium and mild steel. The results showed a decrease in the rate of carbon emissions by 60% when Aluminium is use instead from mild steel, and a decrease of 26% when the-design is modified.

  10. The effects of the space environment on damping materials and damping designs on flexible structures

    NASA Technical Reports Server (NTRS)

    Kluesener, M. F.

    1984-01-01

    The effects of space environments on damping materials and damping designs on flexible structures were investigated. The following items were examined: damping of flexible spacecraft appendages; composite loss factor (n sub s) vs. time in high vacuum for damped test beams and damping of flexible structures. The STEP experiments show inherent damping of flexible structures in space effective possible damping design configurations for space structures, effects of passively damped components on the system loss factor of flexible structures and the effect of space environment on properties of damping materials.

  11. Analysis of Photothermal Characterization of Layered Materials: Design of Optimal Experiments

    NASA Technical Reports Server (NTRS)

    Cole, Kevin D.

    2003-01-01

    In this paper numerical calculations are presented for the steady-periodic temperature in layered materials and functionally-graded materials to simulate photothermal methods for the measurement of thermal properties. No laboratory experiments were performed. The temperature is found from a new Green s function formulation which is particularly well-suited to machine calculation. The simulation method is verified by comparison with literature data for a layered material. The method is applied to a class of two-component functionally-graded materials and results for temperature and sensitivity coefficients are presented. An optimality criterion, based on the sensitivity coefficients, is used for choosing what experimental conditions will be needed for photothermal measurements to determine the spatial distribution of thermal properties. This method for optimal experiment design is completely general and may be applied to any photothermal technique and to any functionally-graded material.

  12. [Design and Preparation of Plant Bionic Materials Based on Optical and Infrared Features Simulation].

    PubMed

    Jiang, Xiao-jun; Lu, Xu-liang; Pan, Jia-liang; Zhang, Shuan-qin

    2015-07-01

    Due to the life characteristics such as physiological structure and transpiration, plants have unique optical and infrared features. In the optical band, because of the common effects of chlorophyll and water, plant leafs show spectral reflectance characteristics change in 550, 680, 1400 and 1900 nm significantly. In the infrared wave band, driven by transpiration, plants could regulate temperature on their own initiative, which make the infrared characteristics of plants different from artificial materials. So palnt bionic materials were proposed to simulate optical and infrared characteristics of plants. By analyzing formation mechanism of optical and infrared features about green plants, the component design and heat-transfer process of plants bionic materials were studied, above these the heat-transfer control formulation was established. Based on water adsorption/release compound, optical pigments and other man-made materials, plant bionic materials preparation methods were designed which could simulate the optical and infrared features of green plants. By chemical casting methods plant bionic material films were prepared, which use polyvinyl alcohol as film forming and water adsorption/release compound, and use optical pigments like chrome green and macromolecule yellow as colouring materials. The research conclusions achieved by testings figured out: water adsorption/release testing showed that the plant bionic materials with a certain thickness could absorb 1.3 kg water per square meter, which could satisfy the water usage of transpiration simulation one day; the optical and infrared simulated effect tests indicated that the plant bionic materials could preferably simulate the spectral reflective performance of green plants in optical wave band (380-2500 nm, expecially in 1400 and 1900 nm which were water absorption wave band of plants), and also it had similar daily infrared radiation variations with green plants, daily average radiation temperature

  13. Advanced composites structural concepts and materials technologies for primary aircraft structures: Design/manufacturing concept assessment

    NASA Technical Reports Server (NTRS)

    Chu, Robert L.; Bayha, Tom D.; Davis, HU; Ingram, J. ED; Shukla, Jay G.

    1992-01-01

    Composite Wing and Fuselage Structural Design/Manufacturing Concepts have been developed and evaluated. Trade studies were performed to determine how well the concepts satisfy the program goals of 25 percent cost savings, 40 percent weight savings with aircraft resizing, and 50 percent part count reduction as compared to the aluminum Lockheed L-1011 baseline. The concepts developed using emerging technologies such as large scale resin transfer molding (RTM), automatic tow placed (ATP), braiding, out-of-autoclave and automated manufacturing processes for both thermoset and thermoplastic materials were evaluated for possible application in the design concepts. Trade studies were used to determine which concepts carry into the detailed design development subtask.

  14. 75 FR 54497 - Ocean Dumping; Guam Ocean Dredged Material Disposal Site Designation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-08

    ... Register (FR). Historically, dredged material generated around Guam by the Navy and the Port Authority of... will, wherever feasible, designate ocean dumping sites beyond the edge of the continental shelf and... continental land mass and does not have a continental shelf. In the ] absence of a shelf break,...

  15. A Study of Learning Performance of E-Learning Materials Design with Knowledge Maps

    ERIC Educational Resources Information Center

    Shaw, Ruey-Shiang

    2010-01-01

    This research investigated the application of knowledge maps in e-learning materials design and hypothesized that knowledge maps would be more effective than e-learning in general at improving the performance and satisfaction of e-learning. In order to test the hypotheses, we conducted an experiment with 175 participants and randomly assigned them…

  16. Designing a Materials Development Course for EFL Student Teachers: Principles and Pitfalls

    ERIC Educational Resources Information Center

    Bouckaert, Marina

    2016-01-01

    This article presents an overview of a newly designed course in materials development at a teacher education institute in the Netherlands. It also includes an evaluation of the course by its participants, student teachers of English as a foreign language (EFL) in Dutch secondary schools. The course overview describes the aims and objectives of the…

  17. Design, Implementation, and Evaluation of GIS-Based Learning Materials in an Introductory Geoscience Course.

    ERIC Educational Resources Information Center

    Hall-Wallace, Michelle K.; McAuliffe, Carla M.

    2002-01-01

    Investigates student learning that occurred with a Geographic Information Systems (GIS) based module on plate tectonics and geologic hazards. Examines factors in the design and implementation of the materials that impacted student learning. Reports positive correlations between student' spatial ability and performance. Includes 17 references.…

  18. Exploring the Effect of Materials Designed with Augmented Reality on Language Learners' Vocabulary Learning

    ERIC Educational Resources Information Center

    Solak, Ekrem; Cakir, Recep

    2015-01-01

    The purpose of this study was to determine the motivational level of the participants in a language classroom towards course materials designed in accordance with augmented reality technology and to identify the correlation between academic achievement and motivational level. 130 undergraduate students from a state-run university in Turkey…

  19. Nickel cadmium cell designs negative to positive material ratio and precharge levels

    NASA Technical Reports Server (NTRS)

    Gross, S.

    1977-01-01

    A review is made of the factors affecting the choices of negative-to-positive materials ratio and negative precharge in nickel-cadmium cells. The effects of these variables on performance are given, and the different methods for setting precharge are evaluated. The effects of special operating requirements on the design are also discussed.

  20. Taguchi statistical design and analysis of cleaning methods for spacecraft materials

    NASA Technical Reports Server (NTRS)

    Lin, Y.; Chung, S.; Kazarians, G. A.; Blosiu, J. O.; Beaudet, R. A.; Quigley, M. S.; Kern, R. G.

    2003-01-01

    In this study, we have extensively tested various cleaning protocols. The variant parameters included the type and concentration of solvent, type of wipe, pretreatment conditions, and various rinsing systems. Taguchi statistical method was used to design and evaluate various cleaning conditions on ten common spacecraft materials.

  1. Evaluation of critical materials in five additional advance design photovoltaic cells

    SciTech Connect

    Smith, S.A.; Watts, R.L.; Martin, P.; Gurwell, W.E.

    1981-02-01

    The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large-scale use of the technologies. The results of the screening of five advanced PV cell designs are presented: (1) indium phosphide/cadmium sulfide, (2) zinc phosphide, (3) cadmium telluride/cadmium sulfide, (4) copper indium selenium, and (5) cadmium selenide photoelectrochemical. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 Gwe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has a 5 GWe of peak capacity by the year 2000, so that the total online capacity for the five cells is 25 GWe. Based on a review of the preliminary baseline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. The CMAP methodology used to identify critical materials is described; and detailed characterizations of the advanced photovoltaic cell designs under investigation, descriptions of additional cell production processes, and the results are presented. (WHK)

  2. A Design and Assessment of a Formative Evaluation of the Principles of Technology Curriculum Materials.

    ERIC Educational Resources Information Center

    McKinney, Floyd L.; Kohan, Alan

    The National Center for Research in Vocational Education (NCRVE) was consulted to improve the formative evaluation design for the Principles of Technology (PT) curriculum materials developed by the Center for Occupational Research and Development (CORD) and the Agency for Instructional Technology (AIT). Because the NCRVE entered the formative…

  3. Graphic Design: A Sustainable Solution to Manage the Contents of Teaching Materials

    ERIC Educational Resources Information Center

    Victor, Garcia Izaguirre; Luisa, Pier Castello Maria; Eduardo, Arvizu Sanchez

    2010-01-01

    There is a concern that the teaching of subjects is applied not only with support from a set of technological devices, but largely in the proper use of teaching and new technologies. Taking this idea, the authors develop a research and sustainable design that result in educational materials in solid content and technological innovation, also to…

  4. Investigating Bandgap Energies, Materials, and Design of Light-Emitting Diodes

    ERIC Educational Resources Information Center

    Wagner, Eugene P., II

    2016-01-01

    A student laboratory experiment to investigate the intrinsic and extrinsic bandgaps, dopant materials, and diode design in light-emitting diodes (LEDs) is presented. The LED intrinsic bandgap is determined by passing a small constant current through the diode and recording the junction voltage variation with temperature. A second visible…

  5. Design for Cataloging Non-Book Materials: Adaptable to Computer Use.

    ERIC Educational Resources Information Center

    Genesee Valley School Development Association, Rochester, NY.

    This design was developed in response to a need for cataloging non-book materials compatible to schools in a nine-county region. Cataloging procedures are outlined for charts, disc recordings, filmloops, filmstrips, flash cards, games, kits, maps and globes, picture slides, audio and video tapes, and transparencies. (AB)

  6. Design Guidelines for the Development of Digital Nutrigenomics Learning Material for Heterogeneous Target Groups

    ERIC Educational Resources Information Center

    Busstra, Maria C.; Hartog, Rob; Kersten, Sander; Muller, Michael

    2007-01-01

    Nutritional genomics, or nutrigenomics, can be considered as the combination of molecular nutrition and genomics. Students who attend courses in nutrigenomics differ with respect to their prior knowledge. This study describes digital nutrigenomics learning material suitable for students from various backgrounds and provides design guidelines for…

  7. Improving Transfer of Learning through Designed Context-Based Instructional Materials

    ERIC Educational Resources Information Center

    Bahtaji, Michael Allan A.

    2015-01-01

    This study investigates the outcome of designed source-text materials in context-based physics learning using validated test questions in mechanics. Two groups of students received context-based instruction (experimental group) and one group received content-based instruction (control group). These three groups of students are only different with…

  8. Incorporating 4MAT Model in Distance Instructional Material--An Innovative Design

    ERIC Educational Resources Information Center

    Nikolaou, Alexandra; Koutsouba, Maria

    2012-01-01

    In an attempt to improve the effectiveness of distance learning, the present study aims to introduce an innovative way of creating and designing distance learning instructional material incorporating Bernice McCarthy's 4MAT Model based on learning styles. According to McCarthy's theory, all students can learn effectively in a cycle of learning…

  9. Instructional Design Considerations in Converting Non-CBT Materials into CBT Courses.

    ERIC Educational Resources Information Center

    Ng, Raymond

    Instructional designers who are asked to convert existing training materials into computer-based training (CBT) must take special precautions to avoid making the product into a sophisticated page turner. Although conversion may save considerable time on subject research and analysis, courses to be delivered through microcomputers may require…

  10. APPLICATION FO FLOW FORMING FOR USE IN RADIOACTIVE MATERIAL PACKAGING DESIGNS

    SciTech Connect

    Blanton, P.; Eberl, K.; Abramczyk, G.

    2012-07-11

    This paper reports on the development and testing performed to demonstrate the use of flow forming as an alternate method of manufacturing containment vessels for use in radioactive material shipping packaging designs. Additionally, ASME Boiler and Pressure Vessel Code, Section III, Subsection NB compliance along with the benefits compared to typical welding of containment vessels will be discussed. SRNL has completed fabrication development and the testing on flow formed containment vessels to demonstrate the use of flow forming as an alternate method of manufacturing a welded 6-inch diameter containment vessel currently used in the 9975 and 9977 radioactive material shipping packaging. Material testing and nondestructive evaluation of the flow formed parts demonstrate compliance to the minimum material requirements specified in applicable parts of ASME Boiler and Pressure Vessel Code, Section II. Destructive burst testing shows comparable results to that of a welded design. The benefits of flow forming as compared to typical welding of containment vessels are significant: dimensional control is improved due to no weld distortion; less final machining; weld fit-up issues associated with pipes and pipe caps are eliminated; post-weld non-destructive testing (i.e., radiography and die penetrant tests) is not necessary; and less fabrication steps are required. Results presented in this paper indicate some of the benefits in adapting flow forming to design of future radioactive material shipping packages containment vessels.

  11. Accelerating the Design of Solar Thermal Fuel Materials through High Throughput Simulations

    SciTech Connect

    Liu, Y; Grossman, JC

    2014-12-01

    Solar thermal fuels (STF) store the energy of sunlight, which can then be released later in the form of heat, offering an emission-free and renewable solution for both solar energy conversion and storage. However, this approach is currently limited by the lack of low-cost materials with high energy density and high stability. In this Letter, we present an ab initio high-throughput computational approach to accelerate the design process and allow for searches over a broad class of materials. The high-throughput screening platform we have developed can run through large numbers of molecules composed of earth-abundant elements and identifies possible metastable structures of a given material. Corresponding isomerization enthalpies associated with the metastable structures are then computed. Using this high-throughput simulation approach, we have discovered molecular structures with high isomerization enthalpies that have the potential to be new candidates for high-energy density STF. We have also discovered physical principles to guide further STF materials design through structural analysis. More broadly, our results illustrate the potential of using high-throughput ab initio simulations to design materials that undergo targeted structural transitions.

  12. Optimal nondestructive test design for maximum sensitivity and minimal redundancy for applications in material characterization

    NASA Astrophysics Data System (ADS)

    Notghi, Bahram; Brigham, John C.

    2013-12-01

    An approach to nondestructive test (NDT) design for material characterization and damage identification in structural components, and more generally in solid continua, is presented and numerically tested. The proposed NDT design approach is based on maximizing a measure of the sensitivity of the test responses to changes in the material properties of the structure while also maximizing a measure of the difference in the response components. As such, the optimally designed NDT provides significant improvement in the ability to solve subsequent inverse characterization problems by extracting the maximum amount of non-redundant information from the system to increase the inverse solution observability. The NDT design approach is theoretically able to include any and all possible design aspects, such as the placement of sensors and actuators and determination of actuation frequency, among others. Through simulated test problems based on the characterization of damage in aluminum structural components utilizing steady-state dynamic surface excitation and localized measurements of displacement, the proposed NDT design approach is shown to provide NDT designs with significantly higher measurement sensitivity as well as lower information redundancy when compared to alternate test approaches. More importantly, the optimized NDT methods are shown to provide consistent and significant improvement in the ability to accurately inversely characterize variations in the Young’s modulus distributions for the simulated test cases considered.

  13. A Data Envelopment Analysis Model for Selecting Material Handling System Designs

    NASA Astrophysics Data System (ADS)

    Liu, Fuh-Hwa Franklin; Kuo, Wan-Ting

    The material handling system under design is an unmanned job shop with an automated guided vehicle that transport loads within the processing machines. The engineering task is to select the design alternatives that are the combinations of the four design factors: the ratio of production time to transportation time, mean job arrival rate to the system, input/output buffer capacities at each processing machine, and the vehicle control strategies. Each of the design alternatives is simulated to collect the upper and lower bounds of the five performance indices. We develop a Data Envelopment Analysis (DEA) model to assess the 180 designs with imprecise data of the five indices. The three-ways factorial experiment analysis for the assessment results indicates the buffer capacity and the interaction of job arrival rate and buffer capacity affect the performance significantly.

  14. Sensory evaluation based fuzzy AHP approach for material selection in customized garment design and development process

    NASA Astrophysics Data System (ADS)

    Hong, Y.; Curteza, A.; Zeng, X.; Bruniaux, P.; Chen, Y.

    2016-06-01

    Material selection is the most difficult section in the customized garment product design and development process. This study aims to create a hierarchical framework for material selection. The analytic hierarchy process and fuzzy sets theories have been applied to mindshare the diverse requirements from the customer and inherent interaction/interdependencies among these requirements. Sensory evaluation ensures a quick and effective selection without complex laboratory test such as KES and FAST, using the professional knowledge of the designers. A real empirical application for the physically disabled people is carried out to demonstrate the proposed method. Both the theoretical and practical background of this paper have indicated the fuzzy analytical network process can capture expert's knowledge existing in the form of incomplete, ambiguous and vague information for the mutual influence on attribute and criteria of the material selection.

  15. New Designs, Materials and Processes for Interstage Structures of Future Launchers

    NASA Astrophysics Data System (ADS)

    Mangas, C. B.; Diaz, V.

    2012-07-01

    Since the 1990’s EADS CASA Espacio has been leading the development of structures made out of advanced composite materials for the upper stage of Ariane 5: Inter Stage Structure (ISS), Vehicle Equipment Bay (VEB), different Payload Adaptor Systems, Satellite Dispensers and other structures. The next generation of launchers will demand an improvement on mechanical performances, reduction of mass and cost, and an optimization of the manufacturing processes. In the frame of the Future Launcher Preparatory Programme (FLPP) promoted by ESA, new designs, materials and processes are being studied and tested, in order to mature the most promising technologies and implement them in the future launchers. Specifically, in this programme these efforts are focused on different ISS structures. Taking as starting point the current ISS of Ariane 5 and IS3 of VEGA, new designs are suggested. Monocoque stiffened with omega stringers is the concept proposed for the ISS, while carbon fibre reinforced plastic (CFRP) - syntactic core sandwich is the one planned for IS3. This paper outlines the work performed in the programme: • Design and analysis of two Inter Stage Structures • Basic characterization tests for new materials: CFRP, syntactic core • Development tests at sample level for the different design solutions: different omega stringers, syncore sandwich • Manufacturing trials for the selected designs • Manufacturing of a sub-scaled demonstrator of the ISS

  16. Computer simulations of realistic microstructures: Implications for simulation-based materials design

    NASA Astrophysics Data System (ADS)

    Singh, Harpreet

    The conventional route of materials development typically involves fabrication of numerous batches of specimens having a range of different microstructures generated via variations of process parameters and measurements of relevant properties of these microstructures to identify the combination of processing conditions that yield the material having desired properties. Clearly, such a trial and error based materials development methodology is expensive, time consuming, and inefficient. Consequently, it is of interest to explore alternate strategies that can lead to a decrease in the cost and time required for development of advanced materials such as composites. Availability of powerful and inexpensive computational power and progress in computational materials science permits advancement of modeling and simulations assisted materials design methodology that may require fewer experiments, and therefore, lower cost and time for materials development. The key facets of such a technology would be computational tools for (i) creating models to generate computer simulated realistic microstructures; (ii) capturing the process-microstructure relationship using these models; and (iii) implementation of simulated microstructures in the computational models for materials behavior. Therefore, development of a general and flexible methodology for simulations of realistic microstructures is crucial for the development of simulations based materials design and development technology. Accordingly, this research concerns development of such a methodology for simulations of realistic microstructures based on experimental quantitative stereological data on few microstructures that can capture relevant details of microstructural geometry (including spatial clustering and second phase particle orientations) and its variations with process parameters in terms of a set of simulation parameters. The interpolation and extrapolation of the simulation parameters can then permit generation

  17. [Design of plant leaf bionic camouflage materials based on spectral analysis].

    PubMed

    Yang, Yu-Jie; Liu, Zhi-Ming; Hu, Bi-Ru; Wu, Wen-Jian

    2011-06-01

    The influence of structure parameters and contents of plant leaves on their reflectance spectra was analyzed using the PROSPECT model. The result showed that the bionic camouflage materials should be provided with coarse surface and spongy inner structure, the refractive index of main content must be close to that of plant leaves, the contents of materials should contain chlorophyll and water, and the content of C-H bond must be strictly controlled. Based on the analysis above, a novel camouflage material, which was constituted by coarse transparent waterproof surface, chlorophyll, water and spongy material, was designed. The result of verifiable experiment showed that the reflectance spectra of camouflage material exhibited the same characteristics as those of plant leaves. The similarity coefficient of reflectance spectrum of the camouflage material and camphor leaves was 0.988 1, and the characteristics of camouflage material did not change after sunlight treatment for three months. The bionic camouflage material, who exhibited a high spectral similarity with plant leaves and a good weather resistance, will be an available method for reconnaissance of hyperspectral imaging hopefully. PMID:21847955

  18. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design

    NASA Astrophysics Data System (ADS)

    Zhang, Yuxuan; Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David; Zhu, Wenzhong

    2014-11-01

    In the developing DEMO divertor, the design of joints between tungsten to other fusion related materials is a significant challenge as a result of the dissimilar physical metallurgy of the materials to be joined. This paper focuses on the design and fabrication of dissimilar brazed joints between tungsten and fusion relevant materials such as EUROFER 97, oxygen-free high thermal conductivity (OFHC) Cu and SS316L using a gold based brazing foil. The main objectives are to develop acceptable brazing procedures for dissimilar joining of tungsten to other fusion compliant materials and to advance the metallurgical understanding within the interfacial region of the brazed joint. Four different butt-type brazed joints were created and characterised, each of which were joined with the aid of a thin brazing foil (Au80Cu19Fe1, in wt.%). Microstructural characterisation and elemental mapping in the transition region of the joint was undertaken and, thereafter, the results were analysed as was the interfacial diffusion characteristics of each material combination produced. Nano-indentation tests are performed at the joint regions and correlated with element composition information in order to understand the effects of diffused elements on mechanical properties. The experimental procedures of specimen fabrication and material characterisation methods are presented. The results of elemental transitions after brazing are reported. Elastic modulus and nano-hardness of each brazed joints are reported.

  19. Space shuttle seal material and design development for earth storable propellant systems

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The results of a program to investigate and characterize seal materials suitable for space shuttle storable propellant systems are given. Two new elastomeric materials were identified as being potentially superior to existing state-of-the art materials for specific sealing applications. These materials were AF-E-124D and AF-E-411. AF-E-124D is a cured perfluorinated polymer suitable for use with dinitrogen tetroxide oxidizer, and hydrazine base fuels. AF-E-411 is an ethylene propylene terpolymer material for hydrazine base fuel service. Data are presented relative to low and high temperature characteristics as well as propellant exposure effects. Types of data included are: mechanical properties, stress strain curves, friction and wear characteristics, compression set and permeability. Sealing tests with a flat poppet-seal valve were conducted for verification of sealing capability. A bibliography includes over 200 references relating to seal design or materials and presents a concise tabulation of the more useful seal design data sources.

  20. Alternative routes for highway shipments of radioactive materials and lessons learned from state designations

    SciTech Connect

    Not Available

    1990-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under docket numbers HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select altemative routes. First, the state must establish a ``state routing agency``, defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with DOTs Guidelines for Selecting Preferred Highway Routes for Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice to DOT of any alternative route designation before the routes are deemed effective. The purpose of this report is to discuss the ``lessons learned`` by the five states within the southern region that have designated alternative or preferred routes under the regulations of the Department of Transportation (DOT) established for the transportation of radioactive materials. The document was prepared by reviewing applicable federal laws and regulations, examining state reports and documents and contacting state officials and routing agencies involved in making routing decisions. In undertaking this project, the Southern States Energy Board hopes to reveal the process used by states that have designated alternative routes and thereby share their experiences (i.e., lessons learned) with other southern states that have yet to make designations.

  1. Alternative routes for highway shipments of radioactive materials and lessons learned from state designations

    SciTech Connect

    Not Available

    1990-07-01

    Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under docket numbers HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select altemative routes. First, the state must establish a state routing agency'', defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with DOTs Guidelines for Selecting Preferred Highway Routes for Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice to DOT of any alternative route designation before the routes are deemed effective. The purpose of this report is to discuss the lessons learned'' by the five states within the southern region that have designated alternative or preferred routes under the regulations of the Department of Transportation (DOT) established for the transportation of radioactive materials. The document was prepared by reviewing applicable federal laws and regulations, examining state reports and documents and contacting state officials and routing agencies involved in making routing decisions. In undertaking this project, the Southern States Energy Board hopes to reveal the process used by states that have designated alternative routes and thereby share their experiences (i.e., lessons learned) with other southern states that have yet to make designations.

  2. Metal-organic Frameworks as A Tunable Platform for Designing Functional Molecular Materials

    PubMed Central

    Wang, Cheng; Liu, Demin

    2013-01-01

    Metal-organic frameworks (MOFs), also known as coordination polymers, represent an interesting class of crystalline molecular materials that are synthesized by combining metal-connecting points and bridging ligands. The modular nature of and mild conditions for MOF synthesis have permitted the rational structural design of numerous MOFs and the incorporation of various functionalities via constituent building blocks. The resulting designer MOFs have shown promise for applications in a number of areas, including gas storage/separation, nonlinear optics/ferroelectricity, catalysis, energy conversion/storage, chemical sensing, biomedical imaging, and drug delivery. The structure-property relationships of MOFs can also be readily established by taking advantage of the knowledge of their detailed atomic structures, which enables fine-tuning of their functionalities for desired applications. Through the combination of molecular synthesis and crystal engineering MOFs thus present an unprecedented opportunity for the rational and precise design of functional materials. PMID:23944646

  3. Engineered materials characterization report for the Yucca Mountain Site Characterization Project. Volume 2, Design data

    SciTech Connect

    Konynenburg, R.A.; McCright, R.D.; Roy, A.K.; Jones, D.A.

    1995-08-01

    This is Volume 2 of the Engineered Materials Characterization Report which presents the design data for candidate materials needed in fabricating different components for both large and medium multi-purpose canister (MPC) disposal containers, waste packages for containing uncanistered spent fuel (UCF), and defense high-level waste (HLW) glass disposal containers. The UCF waste package consists of a disposal container with a basket therein. It is assumed that the waste packages will incorporate all-metallic multibarrier disposal containers to accommodate medium and large MPCs, ULCF, and HLW glass canisters. Unless otherwise specified, the disposal container designs incorporate an outer corrosion-allowance metal barrier over an inner corrosion-resistant metal barrier. The corrosion-allowance barrier, which will be thicker than the inner corrosion-resistant barrier, is designed to undergo corrosion-induced degradation at a very low rate, thus providing the inner barrier protection from the near-field environment for a prolonged service period.

  4. Responsive materials: A novel design for enhanced machine-augmented composites

    PubMed Central

    Bafekrpour, Ehsan; Molotnikov, Andrey; Weaver, James C.; Brechet, Yves; Estrin, Yuri

    2014-01-01

    The concept of novel responsive materials with a displacement conversion capability was further developed through the design of new machine-augmented composites (MACs). Embedded converter machines and MACs with improved geometry were designed and fabricated by multi-material 3D printing. This technique proved to be very effective in fabricating these novel composites with tuneable elastic moduli of the matrix and the embedded machines and excellent bonding between them. Substantial improvement in the displacement conversion efficiency of the new MACs over the existing ones was demonstrated. Also, the new design trebled the energy absorption of the MACs. Applications in energy absorbers as well as mechanical sensors and actuators are thus envisaged. A further type of MACs with conversion ability, viz. conversion of compressive displacements to torsional ones, was also proposed. PMID:24445490

  5. Responsive materials: A novel design for enhanced machine-augmented composites

    NASA Astrophysics Data System (ADS)

    Bafekrpour, Ehsan; Molotnikov, Andrey; Weaver, James C.; Brechet, Yves; Estrin, Yuri

    2014-01-01

    The concept of novel responsive materials with a displacement conversion capability was further developed through the design of new machine-augmented composites (MACs). Embedded converter machines and MACs with improved geometry were designed and fabricated by multi-material 3D printing. This technique proved to be very effective in fabricating these novel composites with tuneable elastic moduli of the matrix and the embedded machines and excellent bonding between them. Substantial improvement in the displacement conversion efficiency of the new MACs over the existing ones was demonstrated. Also, the new design trebled the energy absorption of the MACs. Applications in energy absorbers as well as mechanical sensors and actuators are thus envisaged. A further type of MACs with conversion ability, viz. conversion of compressive displacements to torsional ones, was also proposed.

  6. Responsive materials: a novel design for enhanced machine-augmented composites.

    PubMed

    Bafekrpour, Ehsan; Molotnikov, Andrey; Weaver, James C; Brechet, Yves; Estrin, Yuri

    2014-01-01

    The concept of novel responsive materials with a displacement conversion capability was further developed through the design of new machine-augmented composites (MACs). Embedded converter machines and MACs with improved geometry were designed and fabricated by multi-material 3D printing. This technique proved to be very effective in fabricating these novel composites with tuneable elastic moduli of the matrix and the embedded machines and excellent bonding between them. Substantial improvement in the displacement conversion efficiency of the new MACs over the existing ones was demonstrated. Also, the new design trebled the energy absorption of the MACs. Applications in energy absorbers as well as mechanical sensors and actuators are thus envisaged. A further type of MACs with conversion ability, viz. conversion of compressive displacements to torsional ones, was also proposed. PMID:24445490

  7. Lyotropic liquid crystal engineering-ordered nanostructured small molecule amphiphile self-assembly materials by design.

    PubMed

    Fong, Celesta; Le, Tu; Drummond, Calum J

    2012-02-01

    Future nanoscale soft matter design will be guided to a large extent by the teachings of amphiphile (lipid or surfactant) self-assembly. Ordered nanostructured lyotropic liquid crystalline mesophases may form in select mixtures of amphiphile and solvent. To reproducibly engineer the low energy amphiphile self-assembly of materials for the future, we must first learn the design principles. In this critical review we discuss the evolution of these design rules and in particular discuss recent key findings regarding (i) what drives amphiphile self-assembly, (ii) what governs the self-assembly structures that are formed, and (iii) how can amphiphile self-assembly materials be used to enhance product formulations, including drug delivery vehicles, medical imaging contrast agents, and integral membrane protein crystallisation media. We focus upon the generation of 'dilutable' lyotropic liquid crystal phases with two- and three-dimensional geometries from amphiphilic small molecules (225 references). PMID:21975366

  8. Specimen Designs for Testing Advanced Aeropropulsion Materials Under In-Plane Biaxial Loading

    NASA Technical Reports Server (NTRS)

    Ellis, John R.; Abul-Aziz, Ali

    2003-01-01

    A design study was undertaken to develop specimen designs for testing advanced aeropropulsion materials under in-plane biaxial loading. The focus of initial work was on developing a specimen design suitable for deformation and strength tests to be conducted under monotonic loading. The type of loading initially assumed in this study was the special case of equibiaxial, tensile loading. A specimen design was successfully developed after a lengthy design and optimization process with overall dimensions of 12 by 12 by 0.625 in., and a gage area of 3.875 by 3.875 by 0.080 in. Subsequently, the scope of the work was extended to include the development of a second design tailored for tests involving cyclic loading. A specimen design suitably tailored to meet these requirements was successfully developed with overall dimensions of 12 by 12 by 0.500 in. and a gage area of 2.375 by 2.375 by 0.050 in. Finally, an investigation was made to determine whether the specimen designs developed in this study for equibiaxial, tensile loading could be used without modification to investigate general forms of biaxial loading. For best results, it was concluded that specimen designs need to be optimized and tailored to meet the specific loading requirements of individual research programs.

  9. An Evaluation of Frangible Materials as Veneers on Vented Structural Member Designs

    SciTech Connect

    Jameson, Kevin Jay

    2015-10-01

    Literature shows there has been extensive research and testing done in the area of wall panels and frangible materials. There is evidence from past research that shows it is possible to vent a structure that has had an accidental internal explosion [1]. The reviewed literature shows that most designs vent the entire wall panel versus a frangible material attached to the wall panel. The frangible material attachment points are important to determine the overall loading of the wall panel structure [2]. The materials used in the reviewed literature were securely attached as well as strong enough to remain intact during the pressure loading to move the entire wall panel. Since the vented wall panel was the weakest part of the overall structure, the other walls of the structure were substantially larger. The structure was usually built from concrete and large amounts of steel with dirt and sand over the top of the structure.The study will be conducted at Sandia National Laboratories located in Albuquerque New Mexico. The skeletal structural design for evaluation is a rectangular frame with a square grid pattern constructed from steel. The skeletal structure has been given to the researcher as a design requirement. The grid pattern will be evaluated strictly on plastic deformation and the loading that is applied from the frangible material. The frangible material tested will either fit into the grid or will be a veneer lightly attached to the structure frame. The frangible material may be required on both sides of the structure to adequately represent the application.

  10. Porous materials with pre-designed single-molecule traps for CO2 selective adsorption

    SciTech Connect

    Li, JR; Yu, JM; Lu, WG; Sun, LB; Sculley, J; Balbuena, PB; Zhou, HC

    2013-02-26

    Despite tremendous efforts, precise control in the synthesis of porous materials with pre-designed pore properties for desired applications remains challenging. Newly emerged porous metal-organic materials, such as metal-organic polyhedra and metal-organic frameworks, are amenable to design and property tuning, enabling precise control of functionality by accurate design of structures at the molecular level. Here we propose and validate, both experimentally and computationally, a precisely designed cavity, termed a 'single-molecule trap', with the desired size and properties suitable for trapping target CO2 molecules. Such a single-molecule trap can strengthen CO2-host interactions without evoking chemical bonding, thus showing potential for CO2 capture. Molecular single-molecule traps in the form of metal-organic polyhedra are designed, synthesised and tested for selective adsorption of CO2 over N-2 and CH4, demonstrating the trapping effect. Building these pre-designed single-molecule traps into extended frameworks yields metal-organic frameworks with efficient mass transfer, whereas the CO2 selective adsorption nature of single-molecule traps is preserved.

  11. Synthesis of designed materials by laser-based direct metal deposition technique: Experimental and theoretical approaches

    NASA Astrophysics Data System (ADS)

    Qi, Huan

    Direct metal deposition (DMD), a laser-cladding based solid freeform fabrication technique, is capable of depositing multiple materials at desired composition which makes this technique a flexible method to fabricate heterogeneous components or functionally-graded structures. The inherently rapid cooling rate associated with the laser cladding process enables extended solid solubility in nonequilibrium phases, offering the possibility of tailoring new materials with advanced properties. This technical advantage opens the area of synthesizing a new class of materials designed by topology optimization method which have performance-based material properties. For better understanding of the fundamental phenomena occurring in multi-material laser cladding with coaxial powder injection, a self-consistent 3-D transient model was developed. Physical phenomena including laser-powder interaction, heat transfer, melting, solidification, mass addition, liquid metal flow, and species transportation were modeled and solved with a controlled-volume finite difference method. Level-set method was used to track the evolution of liquid free surface. The distribution of species concentration in cladding layer was obtained using a nonequilibrium partition coefficient model. Simulation results were compared with experimental observations and found to be reasonably matched. Multi-phase material microstructures which have negative coefficients of thermal expansion were studied for their DMD manufacturability. The pixel-based topology-optimal designs are boundary-smoothed by Bezier functions to facilitate toolpath design. It is found that the inevitable diffusion interface between different material-phases degrades the negative thermal expansion property of the whole microstructure. A new design method is proposed for DMD manufacturing. Experimental approaches include identification of laser beam characteristics during different laser-powder-substrate interaction conditions, an

  12. Dynamic simulation of stent deployment - effects of design, material and coating

    NASA Astrophysics Data System (ADS)

    Schiavone, A.; Zhao, L. G.; Abdel-Wahab, A. A.

    2013-07-01

    Dynamic finite-element simulations have been carried out to study the effects of cell design, material choice and drug eluting coating on the mechanical behaviour of stents during deployment. Four representative stent designs have been considered, i.e., Palmaz-Schatz, Cypher, Xience and Endeavor. The former two are made of stainless steel while the latter two made of Co-Cr alloy. Geometric model for each design was created using ProEngineer software, and then imported into Abaqus for simulation of the full process of stent deployment within a diseased artery. In all cases, the delivery system was based on the dynamic expansion of a polyurethane balloon under applied internal pressure. Results showed that the expansion is mainly governed by the design, in particular open-cell design (e.g. Endeavor) tends to have greater expansion than closed-cell design (e.g. Cypher). Dogboning effect was strong for slotted tube design (e.g. Palmaz-Schatz) but reduced significantly for sinusoidal design (e.g. Cypher). Under the same pressure, the maximum von Mises stress in the stent was higher for the open-cell designs and located mostly at the inner corners of each cell. For given deformation, stents made of Co-Cr alloys tend to experience higher stress level than those made of stainless steels, mainly due to the difference in material properties. For artery-plaque system, the maximum stress occurred on the stenosis and dogboning led to stress concentration at the ends of the plaque. The drug eluting coating affected the stent expansion by reducing the recoiling phenomenon considerably, but also raised the stress level on the stent due to property mismatch.

  13. A Review of Material Degradation Modelling for the Analysis and Design of Bioabsorbable Stents.

    PubMed

    Boland, Enda L; Shine, Rosa; Kelly, Nicola; Sweeney, Caoimhe A; McHugh, Peter E

    2016-02-01

    The field of percutaneous coronary intervention has witnessed many progressions over the last few decades, more recently with the advancement of fully degradable bioabsorbable stents. Bioabsorbable materials, such as metallic alloys and aliphatic polyesters, have the potential to yield stents which provide temporary support to the blood vessel and allow native healing of the tissue to occur. Many chemical and physical reactions are reported to play a part in the degradation of such bioabsorbable materials, including, but not limited to, corrosion mechanisms for metals and the hydrolysis and crystallization of the backbone chains in polymers. In the design and analysis of bioabsorbable stents it is important to consider the effect of each aspect of the degradation on the material's in vivo performance. The development of robust computational modelling techniques which fully capture the degradation behaviour of these bioabsorbable materials is a key factor in the design of bioabsorable stents. A critical review of the current computational modelling techniques used in the design and analysis of these next generation devices is presented here, with the main accomplishments and limitations of each technique highlighted. PMID:26271520

  14. Molecular Understanding and Structural-Based Design of Polyacrylamides and Polyacrylates as Antifouling Materials.

    PubMed

    Chen, Hong; Zhao, Chao; Zhang, Mingzhen; Chen, Qiang; Ma, Jie; Zheng, Jie

    2016-04-12

    Design and synthesis of highly bioinert and biocompatible antifouling materials are crucial for a broad range of biomedical and engineering applications. Among antifouling materials, polyacrylamides and polyacrylates have proved so promising because of cheap raw materials, ease of synthesis and applicability, and abundant functional groups. The strong surface hydration and the high surface packing density of polyacrylamides and polyacrylates are considered to be the key contributors to their antifouling property. In this article, we review our studies on the design and synthesis of a series of polyacrylamides and polyacrylates with different molecular structures. These polymers can be fabricated into different architectural forms (brushes, nanoparticles, nanogels, and hydrogels), all of which are highly resistant to the attachment of proteins, cells, and bacteria. We find that small structural changes in the polymers can lead to large enhancement in surface hydration and antifouling performance, both showing a positive correlation. This reveals a general design rule for effective antifouling materials. Furthermore, polyacrylamides and polyacrylates are readily functionalized with other bioactive compounds to achieve different new multifunctionalities. PMID:26986442

  15. Optimal design variable considerations in the use of phase change materials in indirect evaporative cooling

    NASA Astrophysics Data System (ADS)

    Chilakapaty, Ankit Paul

    The demand for sustainable, energy efficient and cost effective heating and cooling solutions is exponentially increasing with the rapid advancement of computation and information technology. Use of latent heat storage materials also known as phase change materials (PCMs) for load leveling is an innovative solution to the data center cooling demands. These materials are commercially available in the form of microcapsules dispersed in water, referred to as the microencapsulated phase change slurries and have higher heat capacity than water. The composition and physical properties of phase change slurries play significant role in energy efficiency of the cooling systems designed implementing these PCM slurries. Objective of this project is to study the effect of PCM particle size, shape and volumetric concentration on overall heat transfer potential of the cooling systems designed with PCM slurries as the heat transfer fluid (HTF). In this study uniform volume heat source model is developed for the simulation of heat transfer potential using phase change materials in the form of bulk temperature difference in a fully developed flow through a circular duct. Results indicate the heat transfer potential increases with PCM volumetric concentration with gradually diminishing returns. Also, spherical PCM particles offer greater heat transfer potential when compared to cylindrical particles. Results of this project will aid in efficient design of cooling systems based on PCM slurries.

  16. Design and Construction of Field Reversed Configuration Plasma Chamber for Plasma Material Interaction Studies

    NASA Astrophysics Data System (ADS)

    Smith, DuWayne L.

    A Field Reversed Configuration (FRC) plasma source was designed and constructed to conduct high energy plasma-materials interaction studies. The purpose of these studies is the development of advanced materials for use in plasma based electric propulsion systems and nuclear fusion containment vessels. Outlined within this thesis is the basic concept of FRC plasmoid creation, an overview of the device design and integration of various diagnostics systems for plasma conditions and characterization, discussion on the variety of material defects resulting from the plasma exposure with methods and tools designed for characterization. Using a Michelson interferometer it was determined that the FRC plasma densities are on the order of ~1021 m-3. A novel dynamic pressure probe was created to measure ion velocities averaging 300 km/s. Compensating flux loop arrays were used to measure magnetic field strength and verify the existence of the FRC plasmoid and when used in combination with density measurements it was determined that the average ion temperatures are ~130 eV. X-ray Photoelectron Spectroscopy (XPS) was employed as a means of characterizing the size and shape of the plasma jet in the sample exposure positions. SEM results from preliminary studies reveal significant morphological changes on plasma facing material surfaces, and use of XRD to elucidate fuel gas-ion implantation strain rates correlated to plasma exposure energies.

  17. Designing small molecule polyaromatic p- and n-type semiconductor materials for organic electronics

    NASA Astrophysics Data System (ADS)

    Collis, Gavin E.

    2015-12-01

    By combining computational aided design with synthetic chemistry, we are able to identify core 2D polyaromatic small molecule templates with the necessary optoelectronic properties for p- and n-type materials. By judicious selection of the functional groups, we can tune the physical properties of the material making them amenable to solution and vacuum deposition. In addition to solubility, we observe that the functional group can influence the thin film molecular packing. By developing structure-property relationships (SPRs) for these families of compounds we observe that some compounds are better suited for use in organic solar cells, while others, varying only slightly in structure, are favoured in organic field effect transistor devices. We also find that the processing conditions can have a dramatic impact on molecular packing (i.e. 1D vs 2D polymorphism) and charge mobility; this has implications for material and device long term stability. We have developed small molecule p- and n-type materials for organic solar cells with efficiencies exceeding 2%. Subtle variations in the functional groups of these materials produces p- and ntype materials with mobilities higher than 0.3 cm2/Vs. We are also interested in using our SPR approach to develop materials for sensor and bioelectronic applications.

  18. Design and Optimization of Passive UHF RFID Tag Antenna for Mounting on or inside Material Layers

    NASA Astrophysics Data System (ADS)

    Shao, Shuai

    There is great desire to employ passive UHF RFID tags for inventory tracking and sensing in a diversity of applications and environments. Owing to its battery-free operation, non-line-of sight detection, low cost, long read range and small form factor, each year billions of RFID tags are being deployed in retail, logistics, manufacturing, biomedical inventories, among many other applications. However, the performance of these RFID systems has not met expectations. This is because a tag's performance deteriorates significantly when mounted on or inside arbitrary materials. The tag antenna is optimized only for a given type of material at a certain location of placement, and detuning takes place when attached to or embedded in materials with dielectric properties outside the design range. Thereby, different customized tags may be needed for identifying objects even within the same class of products. This increases the overall cost of the system. Furthermore, conventional copper foil-based RFID tag antennas are prone to metal fatigue and wear, and cannot survive hostile environments where antennas could be deformed by external forces and failures occur. Therefore, it is essential to understand the interaction between the antenna and the material in the vicinity of the tag, and design general purpose RFID tag antennas possessing excellent electrical performance as well as robust mechanical structure. A particularly challenging application addressed here is designing passive RFID tag antennas for automotive tires. Tires are composed of multiple layers of rubber with different dielectric properties and thicknesses. Furthermore, metallic plies are embedded in the sidewalls and steel belts lie beneath the tread to enforce mechanical integrity. To complicate matters even more, a typical tire experiences a 10% stretching during the construction process. This dissertation focuses on intuitively understanding the interaction between the antenna and the material in the

  19. Influence of design and bearing material on polyethylene wear particle generation in total knee replacement.

    PubMed

    Utzschneider, S; Paulus, A; Datz, J-C; Schroeder, C; Sievers, B; Wegener, B; Jansson, V

    2009-09-01

    Periprosthetic osteolysis is one of the main reasons for revision of arthroplasty. The osteolytic reaction is influenced by the dose, size and shape of the wear particles. For arthroplasty, a low number and biologically less active particles are required. This is the first study which analyzes the impact of different knee designs, combined with crosslinked polyethylenes (sequentially irradiated and annealed as well as remelted techniques), on the amount, size and shape of particles. Overall, six material combinations, four of them with crosslinked polyethylene (XPE) and two of them with ultra-high molecular weight polyethylene (UHMWPE) inserts, including fixed and mobile bearings, were tested in a knee joint simulator. After isolation nearly 100,000 particles were analyzed in size, shape and number by scanning electron microscopy and image analysis. For all the designs, the wear was predominantly smooth and granular with few fibrillar particles. The Scorpio design with the X3 insert, the Natural Knee II design with the Durasul insert and the LCS design, also combined with a crosslinked polyethylene insert, generated statistically significant (P<0.05) lower particle numbers. The particle size was independent of the radiation dose. The wear generated by the LCS knee design (XPE and UHMWPE) had a higher percentage fraction of particles >1microm in size (equivalent circle diameter). The NexGen design, tested with the Prolong insert, showed a high number of particles in the biologically active size range compared with the other crosslinked designs, which could be a predictor for higher biological reactivity. PMID:19375997

  20. A new design of cemented stem using functionally graded materials (FGM).

    PubMed

    Hedia, H S; Aldousari, S M; Abdellatif, A K; Fouda, N

    2014-01-01

    One of the most frequent complications of total hip replacement (THR) is aseptic loosening of femoral component which is primarily due to changes of post-operative stress distribution pattern with respect to intact femur. Stress shielding of the femur is known to be a principal factor in aseptic loosening of hip replacements. Many designers show that a stiff stem shields the surrounding bone from mechanical loading causing stress shielding. Others show that reducing stem stiffness promotes higher proximal interface shear stress which increases the risk of proximal interface failure. Therefore, the task of this investigation is to solve these conflicting problems appeared in the cemented total hip replacement. The finite element method and optimization technique are used in order to find the optimal stem material which gives the optimal available stress distribution between the proximal medial femoral bone and the cement mantle interfaces. The stem is designed using the concept of functionally graded material (FGM) instead of using the conventional most common used stem material. The results showed that there are four feasible solutions from the optimization runs. The best of these designs is to use a cemented stem graded from titanium at the upper stem layer to collagen at the lower stem layer. This new cemented stem design completely eliminates the stress shielding problem at the proximal medial femoral region. The stress shielding using the cemented functionally graded stem is reduced by 98% compared to titanium stem. PMID:24840196