Sample records for negative-index material design

  1. Design and applications of negative index metamaterials

    Microsoft Academic Search

    Tai Anh Lam

    2010-01-01

    Electromagnetic Negative Index Metamaterials (NIM) exhibit many novel phenomena such as negative Snell's law, backward wave propagation, reverse Cerenkov radiation, and reverse Doppler effect. Predicted theoretically by Veselago in 1968 and experimentally demonstrated and verified barely a decade ago, it has enabled many proof-of-concept applications not achievable with ordinary materials. However, from a practical perspective, synthesis issues such as material

  2. Design and applications of negative index metamaterials

    NASA Astrophysics Data System (ADS)

    Lam, Tai Anh

    Electromagnetic Negative Index Metamaterials (NIM) exhibit many novel phenomena such as negative Snell's law, backward wave propagation, reverse Cerenkov radiation, and reverse Doppler effect. Predicted theoretically by Veselago in 1968 and experimentally demonstrated and verified barely a decade ago, it has enabled many proof-of-concept applications not achievable with ordinary materials. However, from a practical perspective, synthesis issues such as material designs and fabrication techniques need to be improved for NIM to be useful. The goal of this work is to investigate and realize the practical potentials of NIM. To achieve this goal, the physical properties of NIM and their implications are reviewed to establish a fundamental theoretical understanding and appreciation. Experimentally, the constituent unit cells that make possible the realization of NIM are described. Unit cell simulation, fabrication, testing, and material properties extraction techniques and tools are developed to form the basic building blocks. In addition to being able to achieve negative index of refractions, NIM can be used to realize a continuum of material values with independent control of elect is permittivity and magnetic permeability. This newly found capability enables the development of the related field of transformation optics. An electromagnetic cloaking device, one of the first major proof-of-concept devices only made possible by the advent of NIM and transformation optics is simulated to demonstrate NIM's versatility. A major effort of this work is the design, fabrication, and testing of a NIM lens to scan phased-array antenna beams to the horizon. Lens design and optimization tools are developed, and the transformation optics technique of conformal mapping is used to transform the lens from a curved geometry to a faceted buckyball shell for easier fabrication. Other NIM applications also investigated are coated dielectric spheres for isotropic NIM unit cells, flat gradient index lenses, waveguide bandpass and bandstop filters, and a microstrip line bandstop filter. Finally, inspired by electromagnetic NIM, acoustic NIM has became a hot research topic in the last couple of years. The fundamentals of acoustic NIM and material synthesis are briefly reviewed. Potential applications in acoustic cloaking, noise cancellation and vibration damping are presented.

  3. Wave propagation in negative index materials

    NASA Astrophysics Data System (ADS)

    Aylo, Rola

    Properties of electromagnetic propagation in materials with negative permittivities and permeabilities were first studied in 1968. In such metamaterials, the electric field vector, the magnetic field vector, and the propagation vector form a left hand triad, thus the name left hand materials. Research in this area was practically non-existent, until about 10 years ago, a composite material consisting of periodic metallic rods and split-ring resonators showed left-handed properties. Because the dimension of the constituents of the metamaterial are small compared to the operating wavelength, it is possible to describe the electromagnetic properties of the composite using the concept of effective permittivity and permeability. In this dissertation, the basic properties of electromagnetic propagation through homogenous left hand materials are first studied. Many of the basic properties of left hand materials are in contrast to those in right hand materials, viz., negative refraction, perfect lensing, and the inverse Doppler effect. Dispersion relations are used to study wave propagation in negative index materials. For the first time to the best of our knowledge, we show that a reduced dispersion relation, obtained from the frequency dependence of the propagation constant by neglecting a linear frequency dependent term, obeys causality. Causality of the propagation constant enables us to use a novel and simple operator formalism approach to derive the underlying partial differential equations for baseband and envelope wave propagation. Various tools for understanding and characterizing left-handed materials are thereafter presented. The transfer matrix method is used to analyze periodic and random structures composed of positive and negative index materials. By random structures we mean randomness in layer position, index of refraction, and thickness. As an application of alternating periodic negative index and positive index structures, we propose a novel sensor using the zero average gap that only appears in such structures which has different properties from the usual Bragg gap occurring in alternating positive index structures. Also in this dissertation, we propose a novel negative index material in the visible range based on nanoparticle dispersed liquid crystal cells. The extended Maxwell Garnett theory, which is combination of the regular Maxwell Garnett and Mie scattering theories, is used to find the effective refractive index of the proposed cell. Nanoparticle dispersed liquid crystal cells can also be used as plasmonic sensors. A theoretical study of such sensors is presented. Finally, fabrication and testing of such cells is proposed and initial progress in fabrication is reported. The final assembly and testing of nanoparticle dispersed liquid crystal cells constitute ongoing and future work.

  4. Theoretical formulation for an electrically small microstrip patch antenna loaded with negative index materials

    Microsoft Academic Search

    J. S. Petko; D. H. Werner

    2005-01-01

    Composite metamaterials that possess simultaneously negative permeability and permittivity, causing them to exhibit a negative index of refraction known, are known as a negative index materials (NIM). An application of NIMs is to increase the power radiated from electrically small antennas. NIMs can also be used to design thin sub-wavelength cavity resonators. We expand on this principle by introducing a

  5. Slow-light-enhanced codirectional couplers with negative index materials.

    PubMed

    Zhao, L; Duan, Wenhui

    2011-05-23

    Optical codirectional coupling structures consisting of two parallel planar waveguides with negative index materials (NIMs) are systematically studied in different configurations using coupled-mode theory under the weak-coupling condition. As a result, we find that the coupling strength between copropagating optical modes can be enhanced in such structures. More importantly, both our analytical derivations and numerical simulations clearly indicate that the slow-light effect in the waveguides with NIMs plays an essential role in such enhancement. The configuration with two conventional positive-index-material cores embedded in NIM claddings (or vice versa) can lead to the strongest enhancement because it can give rise to the slowest light in our scheme. Therefore, as well as offering a fundamental understanding of the slow-light effect in codirectional coupling structures with NIMs for constructing compact photonic devices, our investigations suggest a useful guideline for optimizing the design of codirectional couplers using slow-light systems for both the classical and quantum information processing and communication networks. PMID:21643267

  6. Electromagnetic field energy density in homogeneous negative index materials.

    PubMed

    Shivanand; Webb, Kevin J

    2012-05-01

    An exact separation of both electric and magnetic energies into stored and lost energies is shown to be possible in the special case when the wave impedance is independent of frequency. A general expression for the electromagnetic energy density in such a dispersive medium having a negative refractive index is shown to be accurate in comparison with numerical results. Using an example metamaterial response that provides a negative refractive index, it is shown that negative time-averaged stored energy can occur. The physical meaning of this negative energy is explained as the energy temporarily borrowed by the field from the material. This observation for negative index materials is of interest when approaching properties for a perfect lens. In the broader context, the observation of negative stored energy is of consequence in the study of dispersive materials. PMID:22712096

  7. Design-related losses of double-fishnet negative-index photonic metamaterials

    E-print Network

    Design-related losses of double-fishnet negative-index photonic metamaterials G. Dolling1, M on the performance, especially on the losses, of negative-index metamaterials on the basis of the so-called double.9999) Metamaterials References and links 1. V. M. Shalaev, "Optical negative-index metamaterials," Nature Photon. 1

  8. Creating double negative index materials using the Babinet principle with one metasurface

    E-print Network

    Zhang, Lei; Soukoulis, Costas M; 10.1103/PhysRevB.87.045101

    2013-01-01

    Metamaterials are patterned metallic structures which permit access to a novel electromagnetic response, negative index of refraction, impossible to achieve with naturally occurring materials. Using the Babinet principle, the complementary split ring resonator (SRR) is etched in a metallic plate to provide negative \\epsilon, with perpendicular direction. Here we propose a new design, etched in a metallic plate to provide negative magnetic permeability \\mu, with perpendicular direction. The combined electromagnetic response of this planar metamaterial, where the negative \\mu comes from the aperture and the negative \\epsilon from the remainder of the continuous metallic plate, allows achievement of a double negative index metamaterial (NIM) with only one metasurface and strong transmission. These designs can be used to fabricate NIMs at microwave and optical wavelengths and three-dimensional metamaterials.

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

    NASA Astrophysics Data System (ADS)

    Joseph, Ancemma; Porsezian, K.

    2010-02-01

    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 Schrödinger 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.

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

    SciTech Connect

    Joseph, Ancemma; Porsezian, K. [Department of Physics, School of Physical, Chemical and Applied Sciences, Pondicherry University, Pondicherry 605 014 (India)

    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.

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

    SciTech Connect

    Petrin, A B [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow (Russian Federation)

    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)

  12. Observation of the inverse Doppler effect in negative-index materials at optical frequencies

    Microsoft Academic Search

    Jiabi Chen; Yan Wang; Baohua Jia; Tao Geng; Xiangping Li; Lie Feng; Wei Qian; Bingming Liang; Xuanxiong Zhang; Min Gu; Songlin Zhuang

    2011-01-01

    The Doppler effect is a fundamental frequency shift phenomenon that occurs whenever a wave source and an observer are moving with respect to one another. It has well-established applications in astrophotonics, biological diagnostics, weather and aircraft radar systems, velocimetry and vibrometry. The counterintuitive inverse Doppler effect was theoretically predicted in 1968 by Veselago in negative-index materials. However, because of the

  13. 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

  14. An adaptive Fourier Bessel split-step method and variational techniques applied to nonlinear propagation in negative index materials

    Microsoft Academic Search

    P. P. Banerjee; G. Nehmetallah

    2006-01-01

    Starting from a simple dispersion relation that models negative index materials, we derive and develop the underlying partial differential equation for wave propagation in such a medium. In the first part we study the linear characteristics of wave and beam propagation in NIMs. In the second part we heuristically perform a nonlinear extension of the linear partial differential equation by

  15. Polarization- and direction-independent defect modes in a wide incident-angle range within Bragg gaps by photonic heterostructures containing negative-index materials

    NASA Astrophysics Data System (ADS)

    Lin, M.; Xu, J.; Fang, Y.; Qiu, G.; Ouyang, Z.

    2010-03-01

    We propose a type of photonic heterostructure by combining dielectric one-dimensional (1D) defective photonic crystals (PCs) and magnetic 1D defective PCs. Both of the two PCs consist of alternating positive-index-material (PIM) layers with a negative-index-material (NIM) defect layer. It is demonstrated by transfer matrix method that there is a polarization- and direction-independent defect mode in a wide incident-angle range within Bragg gaps in the heterostructure. The field distributions prove that the dielectric 1D defective PC benefits to achieve the approximately omnidirectional defect mode for TE waves while the magnetic 1D defective PC benefits for TM waves. Such a structure is useful for designing polarization-independent and omnidirectional or large incident angle narrow-passband filters in optical devices.

  16. Optical negative-index metamaterials

    Microsoft Academic Search

    Vladimir M. Shalaev

    2006-01-01

    Artificially engineered metamaterials are now demonstrating unprecedented electromagnetic properties that cannot be obtained with naturally occurring materials. In particular, they provide a route to creating materials that possess a negative refractive index and offer exciting new prospects for manipulating light. This review describes the recent progress made in creating nanostructured metamaterials with a negative index at optical wavelengths, and discusses

  17. PHYSICAL REVIEW B 87, 045101 (2013) Creating double negative index materials using the Babinet principle with one metasurface

    E-print Network

    2013-01-01

    principle with one metasurface Lei Zhang,1,* Thomas Koschny,1 and C. M. Soukoulis1,2, 1 Ames Laboratory metallic plate, allows achievement of a double negative index metamaterial (NIM) with only one metasurface

  18. Graded negative index lens with designable focal length by phononic crystal

    E-print Network

    Deng, Ke; He, Zhaojian; Liu, Zhengyou; Zhao, Heping; Shi, Jing

    2009-01-01

    We realize a flat lens with graded negative refractive index by a two-dimensional phononic crystal. The index-grade is achieved by gradual modification of the filling fraction along the transverse direction to propagation. We demonstrate that this lens can realize the focusing and amplification of parallel incident acoustic waves. A formula for the refractive index profile is derived by which the lens with desired focal length can be precisely designed and the aberrations of image can be effectively reduced. This designable lens is expected to bear significance in applications such as coupling or integration with various types of acoustic devices.

  19. Achromatic negative index lens with diffractive optics

    NASA Astrophysics Data System (ADS)

    Piao, Mingxu; Cui, Qingfeng; Zhang, Bo

    2015-02-01

    In this paper, achromatization of a negative index lens is achieved by introducing the diffractive optical elements (DOEs) into the negative index lens. The diffraction efficiency of the negative index material (NIM) DOEs is deduced based on the special propagating laws and imaging properties of negative index lenses, and the expression for microstructure height is given. As an example, an achromatic refractive–diffractive negative index lens with 150 mm focal length and 15 mm entrance pupil diameter is discussed from wavelength 0.848 ?m through wavelength 0.912 ?m to wavelength 1.114 ?m. According to the deduced expression for the NIM DOEs, the diffraction efficiency is calculated, and the diffraction efficiency curve is fitted by interpolation.

  20. Negative index metamaterial combining magnetic resonators with metal films

    Microsoft Academic Search

    Uday K. Chettiar; Alexander V. Kildishev; Thomas A. Klar; Vladimir M. Shalaev

    2006-01-01

    We present simulation results of a design for negative index materials that\\u000auses magnetic resonators to provide negative permeability and metal film for\\u000anegative permittivity. We also discuss the possibility of using semicontinuous\\u000ametal films to achieve better manufacturability and enhanced impedance\\u000amatching.

  1. Infrared magnetic and negative-index metamaterials

    NASA Astrophysics Data System (ADS)

    Zhang, Shuang

    Negative-index materials have attracted much attention because of their many unconventional optical properties such as negative refractive angle, phase back propagation, reversed Doppler effect and reversed Cherenkov radiation. Recently, much progress has been made in this research area such as demonstrations of negative permeability "metamaterials" in the rf and microwave regimes, and the predictions and demonstrations (largely in the rf) of negative index materials (and predictions of diffraction-less "perfect" imaging in these materials). In this dissertation, fabrication and characterization of several novel metal-based metamaterial that show unconventional IR/optical properties are discussed. While metals provide a negative permittivity at frequencies below the plasma frequency, naturally occurring materials with negative permeability at optical frequencies are not available. Composite electromagnetic materials with resonant structures with sizes much less than the wavelength can act as an effective homogeneous media with a negative permeability. One widely used structure to achieve negative permeability in rf is the so called "split ring resonator" (SRR) proposed by Pendry. By using SRR, the highest resonant frequency that has been obtained is around 1 THz. The complexity of SRR makes it difficult to be further scaled down to reach magnetic resonance at infrared frequencies, even with electron beam lithography. As part of this dissertation, the fabrication, characterization and modeling of arrays of a new nanostructure design with resonances in the mid-IR region and properties that demonstrate strong magnetic activity indicative of negative permeability are described. This is the first experimental work on negative permeability reported in the mid-IR. In addition, interferometric lithography (IL) combined with self-aligned semiconductor processing techniques were used for the fabrication, leading to large area samples with good uniformity. By combining structures with magnetic response and electrical response, a negative refractive index metamaterial is designed and fabricated using IL. The refractive index of the fabricated structure is obtained uniquely from the experimental results by measuring both the amplitude and phase of the transmission and reflectance. This is the first demonstration of negative index metamaterials in the near-IR, about 4 orders of magnitude shorter than previously reported work. Furthermore, parametric studies and experimental results show that better design with very low loss can be achieved, which might lead to more useful applications.

  2. Nonlinear wave propagation in negative index metamaterials

    Microsoft Academic Search

    Nikolaos L. Tsitsas; Dimitri J. Frantzeskakis

    2011-01-01

    Wave propagation in nonlinear negative index meta­ materials is investigated by directly implementing the reductive perturbation method to Faraday's and Ampere's laws. In this way, we derive a second-order and a third-order nonlinear Schrodinger equation, describing solitons of moderate and ultra- short pulse widths, respectively. We find necessary conditions and derive exact bright and dark soliton solutions of these equations

  3. Mirrorless optical parametric oscillations in negative-index microstructures

    Microsoft Academic Search

    A. K. Popov; S. A. Myslivets; V. M. Shalaev

    2008-01-01

    The unique properties of resonant four-wave mixing of backward waves in negative-index materials are investigated. The possibility of realizing miniature mirrorless optical parametric oscillators is shown and their properties are numerically simulated.

  4. Active microwave negative-index metamaterial transmission line with gain.

    PubMed

    Jiang, Tao; Chang, Kihun; Si, Li-Ming; Ran, Lixin; Xin, Hao

    2011-11-11

    We studied the active metamaterial transmission line at microwave frequency. The active composite right-handed or left-handed transmission line was designed to incorporate a germanium tunnel diode with a negative differential resistance property as the gain device at the unit cell level. Measurements of the fabricated planar transmission line structures with one-, two-, and three-unit cells showed that the addition of the dc pumped tunnel diodes not only provided gain but also maintained the left handedness of the transmission line metamaterial. Simulation results agree well with experimental observation. This work demonstrated that negative index material can be obtained with a net gain when an external source is incorporated. PMID:22181744

  5. Development of Bulk Optical Negative Index Fishnet Metamaterials: Achieving a Low-Loss and Broadband Response Through Coupling

    Microsoft Academic Search

    Jason Valentine; Shuang Zhang; Thomas Zentgraf; Xiang Zhang

    2011-01-01

    In this paper, we discuss the development of a bulk negative refractive index metamaterial made of cascaded Bfishnet( structures, with a negative index existing over a broad spectral range. We describe in detail the design of bulk metamaterials, their fabrication and characterization, as well as the mechanism of how coupling of the unit cells can reduce loss in the material

  6. Genetic algorithm for true negative index in plasmonic metamaterials

    NASA Astrophysics Data System (ADS)

    Goforth, Ian A.; Fullager, Daniel B.; Alisafaee, Hossein; Fiddy, Michael A.

    2015-02-01

    We investigate negative index of refraction in plasmonic metamaterials with an emphasis on distinguishing and isolating contributions to negative refraction from spatial dispersion, as a function of metamaterial dimensions on the scale of the wavelength. We explain the design approach using genetic algorithm and provide sample applications including negative refraction.

  7. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    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.

  9. Low-loss negative-index metamaterial at telecommunication wavelengths

    Microsoft Academic Search

    Gunnar Dolling; Christian Enkrich; Martin Wegener; Costas M. Soukoulis; Stefan Linden

    2006-01-01

    We fabricate and characterize a low-loss silver-based negative-index metamaterial based on the design of a recent theoretical proposal. Comparing the measured transmittance and reflectance spectra with theory reveals good agreement. We retrieve a real part of the refractive index of Re(n)=-2 around 1.5 mum wavelength. The maximum of the ratio of the real to the imaginary part of the refractive

  10. 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

  11. 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

  12. Interferometric characterization of a sub-wavelength near-infrared negative index metamaterial.

    PubMed

    Zhang, Xuhuai; Davanço, Marcelo; Maller, Kara; Jarvis, Thomas W; Wu, Chihhui; Fietz, Chris; Korobkin, Dmitriy; Li, Xiaoqin; Shvets, Gennady; Forrest, Stephen R

    2010-08-16

    Negative phase advance through a single layer of near-IR negative index metamaterial (NIM) is identified through interferometric measurements. The NIM unit cell, sub-wavelength in both the lateral and light propagation directions, is comprised of a pair of Au strips separated by two dielectric and one Au film. Numerical simulations show that the negative phase advance through the single-layer sample is consistent with the negative index exhibited by a bulk material comprised of multiple layers of the same structure. We also numerically demonstrate that the negative index band persists in the lossless limit. PMID:20721166

  13. Entanglement creation with negative index metamaterials

    E-print Network

    Michael Siomau; Ali A. Kamli; Sergey A. Moiseev; Barry C. Sanders

    2012-05-21

    We propose a scheme for creating of a maximally entangled state comprising two field quanta. In our scheme, two weak light fields, which are initially prepared in either coherent or polarization states, interact with a composite medium near an interface between a dielectric and a negative index metamaterial. Such interaction leads to a large Kerr nonlinearity, reduction of the group velocity of the light and significant confinement of the light fields while simultaneously avoiding amplitude losses of the incoming radiation. All these considerations make our scheme efficient.

  14. Experimental verification and simulation of negative index of refraction using Snell's law.

    PubMed

    Parazzoli, C G; Greegor, R B; Li, K; Koltenbah, B E C; Tanielian, M

    2003-03-14

    We report the results of a Snell's law experiment on a negative index of refraction material in free space from 12.6 to 13.2 GHz. Numerical simulations using Maxwell's equations solvers show good agreement with the experimental results, confirming the existence of negative index of refraction materials. The index of refraction is a function of frequency. At 12.6 GHz we measure and compute the real part of the index of refraction to be -1.05. The measurements and simulations of the electromagnetic field profiles were performed at distances of 14lambda and 28lambda from the sample; the fields were also computed at 100lambda. PMID:12689029

  15. Active negative-index metamaterial powered by an electron beam

    E-print Network

    Shapiro, Michael

    An active negative index metamaterial that derives its gain from an electron beam is introduced. The metamaterial consists of a stack of equidistant parallel metal plates perforated by a periodic array of holes shaped as ...

  16. Mirrorless Negative-index Parametric Micro-oscillator

    E-print Network

    Alexander K. Popov; Sergei A. Myslivets; Vladimir M. Shalaev

    2008-07-22

    The feasibility and extraordinary properties of mirrorless parametric oscillations in strongly absorbing negative-index metamaterials are shown. They stem from the backwardness of electromagnetic waves inherent to this type of metamaterials.

  17. Robust wedge demonstration to optical negative index metamaterials Nian-Hai Shen,1,a)

    E-print Network

    ://dx.doi.org/10.1063/1.4812240] Nowadays, metamaterials (MMs) have been well-known in a variety of scientific, etc.1­8 To flexibly program the designs of MMs for objective applications, the characterization of MMs, based on Snell's Law. Since the beginning of the field of MMs, the study of negative index metamaterials

  18. Active negative-index metamaterial powered by an electron beam

    NASA Astrophysics Data System (ADS)

    Shapiro, M. A.; Trendafilov, S.; Urzhumov, Y.; Alù, A.; Temkin, R. J.; Shvets, G.

    2012-08-01

    An active negative index metamaterial that derives its gain from an electron beam is introduced. The metamaterial consists of a stack of equidistant parallel metal plates perforated by a periodic array of holes shaped as complementary split-ring resonators. It is shown that this structure supports a negative-index transverse magnetic electromagnetic mode that can resonantly interact with a relativistic electron beam. Such a metamaterial can be used as a coherent radiation source or a particle accelerator.

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

    PubMed

    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 µm(2)) 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 cm(2)) nano-manufactured in this way exhibit a strong, negative index of refraction in the near-infrared spectral range, with excellent figures of merit. PMID:21642984

  20. Negative index metamaterials based on metal-dielectric nanocomposites for imaging applications

    E-print Network

    Sridhar, Srinivas

    Negative index metamaterials based on metal-dielectric nanocomposites for imaging applications L; published online 25 September 2008 Negative index metamaterials are demonstrated based on metal such a negative index metamaterial, we have used a versatile bottom-up nanofabrication approach to prepare a high

  1. Resonant nonlinear optics of backward waves in negative-index metamaterials

    E-print Network

    Alexander K. Popov; Sergei A. Myslivets; Vladimir M. Shalaev

    2008-08-14

    The extraordinary properties of resonant four-wave mixing of backward waves in doped negative-index materials are investigated. The feasibility of independent engineering of negative refractive index and nonlinear optical response as well as quantum control of the nonlinear propagation process in such composites is shown due to the coherent energy transfer from the control to the signal field. Laser-induced transparency, quantum switching, frequency-tunable narrow-band filtering, amplification, and realizing a miniature mirrorless optical parametric generator of the entangled backward and ordinary waves are among the possible applications of the investigated processes.

  2. Subpicosecond optical switching with a negative index metamaterial.

    PubMed

    Dani, Keshav M; Ku, Zahyun; Upadhya, Prashanth C; Prasankumar, Rohit P; Brueck, S R J; Taylor, Antoinette J

    2009-10-01

    We demonstrate a nanoscale, subpicosecond (ps) metamaterial device capable of terabit/second all-optical communication in the near-IR. The 600 fs response, 2 orders of magnitude faster than previously reported, is achieved by accessing a previously unused regime of high-injection level, subpicosecond carrier dynamics in the alpha-Si dielectric layer of the metamaterial. Further, we utilize a previously unrecognized, higher-order, shorter-wavelength negative-index resonance in the fishnet structure, thereby extending device functionality (via structural tuning of device dimensions) over 1.0-2.0 microm. The pump energy required to modulate a single bit is only 3 nJ over our current 700 microm(2) area device and can be easily scaled into the picoJoule regime with smaller cross sectional areas. PMID:19737005

  3. Electromagnetism in multicoaxial negative-index metamaterial cables

    NASA Astrophysics Data System (ADS)

    Djafari-Rouhani, Bahram; Kushwaha, Manvir

    2011-03-01

    By using an elegant Green [or response] function theory, which does not require matching of the messy boundary conditions, we investigate the surface plasmon excitations in the multicoaxial cylindrical cables made up of negative-index metamaterials. The multicoaxial cables with {dispersive metamaterial components exhibit rather richer (and complex) plasmon spectrum with each interface supporting two modes: one TM and the other TE for (the integer order of the Bessel function) m ? 0 . The cables with nondispersive metamaterial components bear a different tale: they do not support simultaneously both TM and TE modes over the whole range of propagation vector. The computed local and total density of states enable us to substantiate spatial positions of the modes in the spectrum. Such quasi-one dimensional systems as studied here should prove to be the milestones of the emerging optoelectronics and telecommunications systems.

  4. Designing Printed Instructional Materials.

    ERIC Educational Resources Information Center

    Burbank, Lucille; Pett, Dennis

    1986-01-01

    Discusses the importance of identifying the audience and determining specific objectives when designing printed instructional materials that will communicate effectively and provides detailed guidelines for dealing with such design factors as content, writing style, typography, illustrations, and page organization. (MBR)

  5. Materials in design

    E-print Network

    Perata, Alfredo Ferando

    1970-01-01

    TBA" AS'", lJNIYKSIT'i LI8RARY MATERIALS IN DESIGN A Report by Alfredo Ferando Perata Submitted to the Graduate College of the Texas A&M University in partial fulfillment of the reouirement for the degree of MASTER OF EiVGINFERING January... 1970 Major Subject: Mechanical Engineering ABSTRACT Materials in Design Alfredo F. Perata Directed by: Dr. H. Richard Thornton The selection of the right material is one of the first and important steps in design. Because of this, a thoughtful...

  6. Tunable split-ring resonators for nonlinear negative-index metamaterials

    E-print Network

    Tunable split-ring resonators for nonlinear negative-index metamaterials Ilya V. Shadrivov, Steven; (999.9999) Metamaterials. References and links 1. C. Soukoulis, "Bending back light: The science. Drachev, and A. V. Kildishev, "Negative index of refraction in optical metamaterials," Opt. Lett. 30, 3356

  7. Materials in design 

    E-print Network

    Perata, Alfredo Ferando

    1970-01-01

    -Ferrous Metals Copper alloys Aluminum Magnesium Lead Zinc Tin Non-Metallic Materials Wood Stone Brick Cement Cont rete Rubber Leather Asbestos Mica Ceramics Glass Engineering design has to have in consideration, the use to which the material... certain lubrication (wettability) g) Good corrosion resistance h) Good wear resistance i) Adequate high softening point to withstand any service temperature j) High thermal conductivity to dissipate heat from the surface BBBM 1 Tin base Babbitts...

  8. 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…

  9. Designer quantum materials

    NASA Astrophysics Data System (ADS)

    Srinivasa, Vanita

    Spin-based quantum information processing relies on the ability to identify and coherently manipulate quantum bits (qubits) existing in nature in the form of spin-½ particles such as electrons. The work described in this thesis is based on an alternative perspective: that these spin-½ objects, together with their interactions, can be regarded as building blocks of a variety of "designer quantum materials" with features not present for isolated single spins. Theoretical proposals are presented for two classes of spin-based designer quantum materials relevant for quantum information transport and manipulation. The first class of materials involves spin-½ networks coupled by spatially-varying exchange interactions, in which moving domain walls can produce topologically-stable "flying spin qubits," and pairs of domain walls can be used to generate and transport Einstein-Podolsky-Rosen pairs of entangled qubits. The effective exchange between two domain-wall qubits can be tuned by adjusting the positions of the domain walls and can be ferromagnetic even when all spin-spin couplings are antiferromagnetic. The second class of designer quantum materials consists of electron spins in quantum wires with spatially-varying spin-orbit coupling. The presence of the spin-orbit interaction introduces pseudo-Zeeman couplings of the electron spins to effective magnetic fields and further enhances the building-block toolset: by periodically modulating this spin-orbit coupling in space, it is possible to create the spatial analogue of spin resonance, without the need for any real magnetic fields. The mapping of time-dependent operations onto a spatial axis suggests a new mode for quantum information processing in which gate operations are encoded into the band structure of the material.

  10. Experimental Verification of a Negative Index of Refraction

    Microsoft Academic Search

    R. A. Shelby; D. R. Smith; S. Schultz

    2001-01-01

    We present experimental scattering data at microwave frequencies on a structured metamaterial that exhibits a frequency band where the effective index of refraction (n) is negative. The material consists of a two-dimensional array of repeated unit cells of copper strips and split ring resonators on interlocking strips of standard circuit board material. By measuring the scattering angle of the transmitted

  11. Demonstration of metal-dielectric negative-index metamaterials with improved performance at optical frequencies

    Microsoft Academic Search

    Shuang Zhang; Wenjun Fan; Kevin J. Malloy; Steven R. J. Brueck; Nicolae C. Panoiu; Richard M. Osgood

    2006-01-01

    We experimentally demonstrate a comparatively low-loss negative-index metamaterial with the magnitude of the real part of the index comparable with the imaginary part. Over 40% transmission is achieved in the negative-index region by structural adjustment of the impedance matching between the metamaterial and the air-substrate claddings. This structure has the potential of achieving high transmission and small loss in the

  12. Extended slow-light field enhancement in positive-index/negative-index heterostructures

    NASA Astrophysics Data System (ADS)

    Foteinopoulou, S.; Vigneron, J. P.

    2013-11-01

    We present a biwaveguide paradigm composed of joined positive-index-material (PIM)/negative-index-material (NIM) slabs, demonstrating ultraslow-light propagation stemming from the competing propagation disposition in the PIM and NIM regions. We report for the first time a mesoscopic extended electromagnetic (EM) enhancement covering regions of the order of the free-space wavelength, enabled by the slow-light mode in our system. Our dynamic numerical results are consistent with our developed theoretical model, predicting an EM energy accumulation reminiscent of a charging capacitor. Our analysis reveals that spatial compression is not a requirement for EM enhancement in slow-light systems and stresses the merits of a high coupling efficiency, strong temporal compression, monomodality, and modal index bandwidth—all present in our proposed paradigm. Furthermore, we show that the heterostructure waveguide mode is an extraordinary entity with a unique energy velocity, which is opposite to the Poynting vector in one of the participant waveguides. We believe that these results will inspire new slow-light platforms relevant to the collective harvesting of strong light-matter interactions.

  13. Gain and plasmon dynamics in active negative-index metamaterials.

    PubMed

    Wuestner, Sebastian; Pusch, Andreas; Tsakmakidis, Kosmas L; Hamm, Joachim M; Hess, Ortwin

    2011-09-13

    Photonic metamaterials allow for a range of exciting applications unattainable with ordinary dielectrics. However, the metallic nature of their meta-atoms may result in increased optical losses. Gain-enhanced metamaterials are a potential solution to this problem, but the conception of realistic, three-dimensional designs is a challenging task. Starting from fundamental electrodynamic and quantum mechanical equations, we establish and deploy a rigorous theoretical model for the spatial and temporal interaction of lightwaves with free and bound electrons inside and around metallic (nano-) structures and gain media. The derived numerical framework allows us to self-consistently study the dynamics and impact of the coherent plasmon-gain interaction, nonlinear saturation, field enhancement, radiative damping and spatial dispersion. Using numerical pump-probe experiments on a double-fishnet metamaterial structure with dye molecule inclusions, we investigate the build-up of the inversion profile and the formation of the plasmonic modes in a low-Q cavity. We find that full loss compensation occurs in a regime where the real part of the effective refractive index of the metamaterial becomes more negative compared to the passive case. Our results provide a deep insight into how internal processes affect the overall optical properties of active photonic metamaterials fostering new approaches to the design of practical, loss-compensated plasmonic nanostructures. PMID:21807726

  14. 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

  15. Soft 3D acoustic metamaterial with negative index

    NASA Astrophysics Data System (ADS)

    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.

  16. Four-wave mixing, quantum control and compensating losses in doped negative-index photonic metamaterials

    E-print Network

    Alexander K. Popov; Sergey A. Myslivets; Thomas F. George; Vladimir M. Shalaev

    2007-08-13

    The possibility of compensating absorption in negative-index metatamterials (NIMs) doped by resonant nonlinear-optical centers is shown. The role of quantum interference and extraordinary properties of four-wave parametric amplification of counter-propagating electromagnetic waves in NIMs are discussed.

  17. Negative index metamaterials based on metal-dielectric nanocomposites for imaging applications

    Microsoft Academic Search

    L. Menon; W. T. Lu; A. L. Friedman; S. P. Bennett; D. Heiman; S. Sridhar

    2008-01-01

    Negative index metamaterials are demonstrated based on metal-dielectric nanocomposites prepared using a versatile bottom-up nanofabrication approach. The method involves the incorporation of vertically aligned metal nanowires such as Au and Ag inside dielectric aluminum oxide nanotemplates. Optical absorbance measurements show resonance peaks corresponding to the transverse and longitudinal surface plasmon modes. A quantitative model based on effective medium theory is

  18. Compensating losses in negative-index metamaterials by optical parametric amplification

    E-print Network

    Shalaev, Vladimir M.

    with no cavity in strongly absorbing negative-index metamaterials. The opposite directions of the wave vector- edented linear and nonlinear electromagnetic proper- ties. The opposite directions of the wave and Poyn- ting vectors inherent for NIMs lead to extraordinary properties for basic optical processes

  19. Nature-Based Optimization of 2D Negative-Index Metamaterials

    E-print Network

    Shalaev, Vladimir M.

    -based optimization tech- niques -- the genetic algorithm (GA) [1] and particle swarm optimization (PSO) [2 a properly-defined figure of merit. Genetic Algorithm and Particle Swarm Optimization The GA is a powerfulNature-Based Optimization of 2D Negative-Index Metamaterials Do-Hoon Kwon*1, Zikri Bayraktar1

  20. 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 ? × 0.29 ? 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

  1. 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 ? × 0.29 ? 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

  2. Negative-index metamaterials: second-harmonic generation, Manley–Rowe relations and parametric amplification

    Microsoft Academic Search

    A. K. Popov; Vladimir M. Shalaev

    2006-01-01

    Second harmonic generation and optical parametric amplification in negative-index metamaterials (NIMs) are studied. The opposite\\u000a directions of the wave vector and the Poynting vector in NIMs results in a “backward” phase-matching condition, causing significant\\u000a changes in the Manley–Rowe relations and spatial distributions of the coupled field intensities. It is shown that absorption\\u000a in NIMs can be compensated by backward optical

  3. Negative-index metamaterials: second-harmonic generation, Manley-Rowe relations and parametric amplification

    Microsoft Academic Search

    A. K. Popov; V. M. Shalaev

    2006-01-01

    Second harmonic generation and optical parametric amplification in negative-index metamaterials (NIMs) are studied. The opposite directions of the wave vector and the Poynting vector in NIMs results in a ``backward'' phase-matching condition, causing significant changes in the Manley-Rowe relations and spatial distributions of the coupled field intensities. It is shown that absorption in NIMs can be compensated by backward optical

  4. Comparing guided modal properties of surface waves along single- and double-negative indexed slab waveguides

    Microsoft Academic Search

    K. Y. Kim; Y. K. Cho

    2010-01-01

    The guided dispersion characteristics of the fundamental symmetric and asymmetric modes of surface waves along single- and\\u000a double-negative indexed slab waveguides are investigated, and a comparative analysis made when varying the single- and double-negative\\u000a permittivity and permeability. While the values of the permittivity and permeability of the slab region are varied to obtain\\u000a a salient picture of the guided dispersion

  5. Negative Index Metamaterials for Superlenses Based on Metal-Dielectric Nanocomposites

    Microsoft Academic Search

    Latika Menon; Wentao Lu; Adam Friedman; Steven Bennett; Donald Heiman; Srinivas Sridhar

    2008-01-01

    Negative index metamaterials are demonstrated based on metal-dielectric nanocomposites. The nanocomposites are prepared using a versatile bottom-up nanofabrication approach involving the incorporation of vertically aligned metal nanowires such as Au and Ag inside dielectric aluminum oxide nanotemplates. Aluminum oxide nanotemplates with specific pore dimensions are fabricated by means of electrochemical anodization. Following this, Au\\/Ag nanowires with specific wire dimensions are

  6. Material feedback in digital design tools

    E-print Network

    Stanton, Christian J

    2009-01-01

    How do design tools feedback material behavior to the designer? Digital design tools in use by designers today provide a rich environment for design of form but offer little feedback of the material that ultimately realize ...

  7. Negative-Index Metamaterials: Second-Harmonic Generation, Manley-Rowe Relations and Parametric Amplification

    E-print Network

    A. K. Popov; Vladimir M. Shalaev

    2006-01-10

    Second harmonic generation and optical parametric amplification in negative-index metamaterials (NIMs) are studied. The opposite directions of the wave vector and the Poynting vector in NIMs results in a "backward" phase-matching condition, causing significant changes in the Manley-Rowe relations and spatial distributions of the coupled field intensities. It is shown that absorption in NIMs can be compensated by backward optical parametric amplification. The possibility of distributed-feedback parametric oscillation with no cavity has been demonstrated. The feasibility of the generation of entangled pairs of left- and right-handed counter-propagating photons is discussed.

  8. 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.

  9. 4.510/4.501 Materializing Design

    E-print Network

    Entekhabi, Dara

    Cutting, FDM, 3D printing] - Materials and methods to compute designs through scripting, parametric4.510/4.501 Materializing Design Professor Lawrence Sass Department of Architecture MIT TEACHING ­ Schodek Digital Fabrications ­ Architectural and Material Techniques ­ Lisa Iwamoto COURSE DESCRIPTION

  10. Low-frequency surface plasmon excitations in multicoaxial negative-index metamaterial cables

    NASA Astrophysics Data System (ADS)

    Djafari-Rouhani, Bahram; Kushwaha, Manvir

    2010-03-01

    By using an elegant response function theory, which does not require matching of the messy boundary conditions, we investigate the surface plasmon excitations in the multicoaxial cylindrical cables made up of negative-index metamaterials. The multicoaxial cables with dispersive metamaterial components exhibit rather richer (and complex) plasmon spectrum with each interface supporting two modes: one TM and the other TE for (the integer order of the Bessel function) m 0. The cables with nondispersive metamaterial components bear a different tale: they do not support simultaneously both TM and TE modes over the whole range of propagation vector. The computed local and total density of states enable us to substantiate spatial positions of the modes in the spectrum. Such quasi-one dimensional systems as studied here should prove to be the milestones of the emerging optoelectronics and telecommunications systems.

  11. 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.

  12. Integrated Materials and Products Design: Design of Blast Resistance Panels and Materials

    Microsoft Academic Search

    H. J. Choi

    Integrated Materials and Products Design (IMPD) is a new paradigm of systems-based design to enhance product performance by concurrently tailoring materials and product. IMPD involves the development of new materials with specific properties to meet design requirements. In traditional approach, material selection design (Ashy, 2005) , the design alternatives from a material database are screened, ranked and then chosen from

  13. Free-space microwave focusing by a negative-index gradient lens T. Driscolla

    E-print Network

    Nemat-Nasser, Sia

    as steps forward in de- sign complexity and construction technique. Using ray-tracing software written and permeability are known as left-handed materials. Their complexity and our understanding of their properties structural integrity and is time consuming to construct, and limits design complexity.8,9 Limitations

  14. www.srl.gatech.edu Material Design vs. Material Selection

    E-print Network

    Laboratory Outline and Running Icon Motivation and Background Method: The Design Space Expansion Strategywww.srl.gatech.edu Material Design vs. Material Selection A Trade-off Between Design Freedom and Design Simplicity Stephanie C. Thompson Masters Thesis Presentation June 12, 2007 Reading committee

  15. Material and processes selection in conceptual design 

    E-print Network

    Krishnakumar, Karthikeyan

    2005-02-17

    Materials and manufacturing processes are an integral part of the design of a product. The need to combine materials and manufacturing processes selection during the early stages of the design has previously been realized. ...

  16. Material and processes selection in conceptual design

    E-print Network

    Krishnakumar, Karthikeyan

    2005-02-17

    Materials and manufacturing processes are an integral part of the design of a product. The need to combine materials and manufacturing processes selection during the early stages of the design has previously been realized. The work that generally...

  17. 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.

  18. Effects of Numerical Dispersion on the Accuracy of FDTD Modeling of Propagating and Evanescent Waves in Negative Index Media

    E-print Network

    Effects of Numerical Dispersion on the Accuracy of FDTD Modeling of Propagating and Evanescent Waves in Negative Index Media Costas D. Sarris The Edward S. Rogers Sr. Department of Electrical media. Yet, a survey of the relevant FDTD literature indicates a number of contradictory results, which

  19. 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.

  20. Optimal Design of Heterogeneous Materials

    E-print Network

    Torquato, Salvatore

    materials (phases), such as a composite, or the same material in different states, such as a polycrystal (1 examples include aligned and chopped fiber composites, particulate composites, powders, interpenetrating multiphase composites, cellular solids, colloids, gels, foams, phase- separated metallic alloys

  1. Computational methodologies for designing materials

    Microsoft Academic Search

    Talat S Rahman

    2009-01-01

    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

  2. Designing materials for plasmonic systems

    E-print Network

    Blaber, Martin G; Ford, Michael J

    2009-01-01

    We use electronic structure calculations based upon density functional theory to search for ideal plasmonic materials among the alkali noble intermetallics. Importantly, we use density functional perturbation theory to calculate the electron-phonon interaction and from there use a first order solution to the Boltzmann equation to estimate the phenomenological damping frequency in the Drude dielectric function. We discuss the necessary electronic features of a plasmonic material and investigate the optical properties of the alkali-noble intermetallics in terms of some generic plasmonic system quality factors. We conclude that at low negative permittivities, KAu with a damping frequency of 0.0224 eV and a high optical gap to bare plasma frequency ratio, outperforms gold and to some extent silver as a plasmonic material. Unfortunately, a low plasma frequency (1.54 eV) reduces its utility in modern plasmonics applications. We also discuss, briefly, the effect of local fields on the optical properties of these mat...

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

    SciTech Connect

    Bradley, Paul A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    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.

  4. 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.

  5. 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.

  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. Integrated design of structures, controls, and materials

    NASA Technical Reports Server (NTRS)

    Blankenship, G. L.

    1994-01-01

    In this talk we shall discuss algorithms and CAD tools for the design and analysis of structures for high performance applications using advanced composite materials. An extensive mathematical theory for optimal structural (e.g., shape) design was developed over the past thirty years. Aspects of this theory have been used in the design of components for hypersonic vehicles and thermal diffusion systems based on homogeneous materials. Enhancement of the design methods to include optimization of the microstructure of the component is a significant innovation which can lead to major enhancements in component performance. Our work is focused on the adaptation of existing theories of optimal structural design (e.g., optimal shape design) to treat the design of structures using advanced composite materials (e.g., fiber reinforced, resin matrix materials). In this talk we shall discuss models and algorithms for the design of simple structures from composite materials, focussing on a problem in thermal management. We shall also discuss methods for the integration of active structural controls into the design process.

  8. Microstructural design in cellular materials. Final report

    SciTech Connect

    Gibson, L.J.

    1995-12-01

    Cellular materials can be designed to have exceptional mechanical efficiency. In this project we have examined 2 cellular microstructures which give improved mechanical performance: honeycomb beams, with aligned holes parallel to the longitudinal axis of the beam and microsandwich foams, with cell walls designed to act as sandwich panels on a microstructural scale. We have also initiated work on interpenetrating composites using a cellular material as one phase.

  9. METAMATERIALS: Large-area printed 3D negative-index metamaterial is flexible -Laser Focus World http://www.laserfocusworld.com/articles/print/volume-47/issue-8/world-news/metamaterials-large-area-printed-3d-negative-index-metamaterial-is-flexible.html[8/1

    E-print Network

    Rogers, John A.

    METAMATERIALS: Large-area printed 3D negative-index metamaterial is flexible - Laser Focus World http://www.laserfocusworld.com/articles/print/volume-47/issue-8/world-news/metamaterials-large-area-printed-3d-negative-index-metamaterial-is-flexible.html[8/12/2011 3:45:06 PM] About · Advertise · Advertise

  10. 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.

  11. Optimization of material properties needed for material design of components made of multi-heterogeneous materials

    Microsoft Academic Search

    Xiu-Juan Zhang; Ke-Zhang Chen; Xin-An Feng

    2004-01-01

    In order to design the components made of multi-heterogeneous materials for high-tech applications, a new design method has been developed and is implemented from functional requirements in high-tech applications to a component’s configuration, to material properties, and to material microstructures and\\/or constituent compositions. Based on the new design method, this paper develops a detailed approach for the second phase (i.e.,

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

    E-print Network

    Sadatgol, Mehdi; Yang, Lan; Güney, Durdu Ö

    2015-01-01

    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 fundamental challenge to the most fascinating applications of metamaterials. Based on a novel plasmon injection (PI or \\Pi) 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 arbitrary form of incident waves. The \\Pi-scheme is fundamentally different than major optical amplification schemes. It does not require gain medium, interaction with phonons, or any nonlinear medium. The \\Pi-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 fin...

  13. Concurrent design of hierarchical materials and structures

    Microsoft Academic Search

    D. L. McDowell; G. B. Olson

    \\u000a Significant achievements have been demonstrated in computational materials design and its broadening application in concurrent\\u000a engineering. Best practices are assessed and opportunities for improvement identified, with implications for modeling and\\u000a simulation in science and engineering. Successful examples of integration in undergraduate education await broader dissemination.

  14. Concurrent design of hierarchical materials and structures

    Microsoft Academic Search

    D. L. McDowell; G. B. Olson

    2008-01-01

    Significant achievements have been demonstrated in computational materials design and its broadening application in concurrent\\u000a engineering. Best practices are assessed and opportunities for improvement identified, with implications for modeling and\\u000a simulation in science and engineering. Successful examples of integration in undergraduate education await broader dissemination.

  15. Phase control of switching from positive to negative index material in a four-level atomic system

    Microsoft Academic Search

    Hongjun Zhang; Yueping Niu; Hui Sun; Jian Luo; Shangqing Gong

    2008-01-01

    Electric and magnetic responses of the medium to the probe field are analysed in a four-level loop atomic system by taking into account the relative phase of the applied fields. An interesting phenomenon is found: under suitable conditions, a change of the refractive index from positive to negative can occur by modulating the relative phase of the applied fields. Then

  16. Rational Design of Optical Chemosensor Materials

    Microsoft Academic Search

    V. A. Sazhnikov; M. V. Alfimov

    A rational approach to the design of optical chemosensor materials based on consideration of intermolecular interactions between analytes, indicators and matrices is discussed. In a general case, all types of interactions between these components must be taken into account. The results of an experimental study of the fluorescence spectra of a relatively simple acridinic dye, 2,7-dimethyl-9-(ditolylamino)acridine, immobilized in polysterene, PMMA

  17. Saving Material with Systematic Process Designs

    NASA Astrophysics Data System (ADS)

    Kerausch, M.

    2011-08-01

    Global competition is forcing the stamping industry to further increase quality, to shorten time-to-market and to reduce total cost. Continuous balancing between these classical time-cost-quality targets throughout the product development cycle is required to ensure future economical success. In today's industrial practice, die layout standards are typically assumed to implicitly ensure the balancing of company specific time-cost-quality targets. Although die layout standards are a very successful approach, there are two methodical disadvantages. First, the capabilities for tool design have to be continuously adapted to technological innovations; e.g. to take advantage of the full forming capability of new materials. Secondly, the great variety of die design aspects have to be reduced to a generic rule or guideline; e.g. binder shape, draw-in conditions or the use of drawbeads. Therefore, it is important to not overlook cost or quality opportunities when applying die design standards. This paper describes a systematic workflow with focus on minimizing material consumption. The starting point of the investigation is a full process plan for a typical structural part. All requirements are definedaccording to a predefined set of die design standards with industrial relevance are fulfilled. In a first step binder and addendum geometry is systematically checked for material saving potentials. In a second step, blank shape and draw-in are adjusted to meet thinning, wrinkling and springback targets for a minimum blank solution. Finally the identified die layout is validated with respect to production robustness versus splits, wrinkles and springback. For all three steps the applied methodology is based on finite element simulation combined with a stochastical variation of input variables. With the proposed workflow a well-balanced (time-cost-quality) production process assuring minimal material consumption can be achieved.

  18. 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 detailed later in this Report.

  19. Use of advanced composite materials for innovative building design solutions/

    E-print Network

    Lau, Tak-bun, Denvid

    2009-01-01

    Advanced composite materials become popular in construction industry for the innovative building design solutions including strengthening and retrofitting of existing structures. The interface between different materials ...

  20. First principles materials design for semiconductor spintronics

    Microsoft Academic Search

    K. Sato; H. Katayama-Yoshida

    2002-01-01

    Materials design of new functional diluted magnetic semiconductors (DMSs) is presented based on first principles calculations. The stability of the ferromagnetic state in ZnO-, ZnS-, ZnSe-, ZnTe-, GaAs- and GaN-based DMSs is investigated systematically and it is suggested that V- or Cr-doped ZnO, ZnS, ZnSe and ZnTe are candidates for high-TC ferromagnetic DMSs. V-, Cr- or Mn-doped GaAs and GaN

  1. Optimized energy harvesting materials and generator design

    NASA Astrophysics Data System (ADS)

    Graf, Christian; Hitzbleck, Julia; Feller, Torsten; Clauberg, Karin; Wagner, Joachim; Krause, Jens; Maas, Jürgen

    2013-04-01

    Electroactive polymers are soft capacitors made of thin elastic and electrically insulating films coated with compliant electrodes offering a large amount of deformation. They can either be used as actuators by applying an electric charge or they can be used as energy converters based on the electrostatic principle. These unique properties enable the industrial development of highly efficient and environmentally sustainable energy converters, which opens up the possibility to further exploit large renewable and inexhaustible energy sources like wind and water that are widely unused otherwise. Compared to other electroactive polymer materials, polyurethanes, whose formulations have been systematically modified and optimized for energy harvesting applications, have certain advantages over silicones and acrylates. The inherently higher dipole content results in a significantly increased permittivity and the dielectric breakdown strength is higher, too, whereby the overall specific energy, a measure for the energy gain, is better by at least factor ten, i.e. more than ten times the energy can be gained out of the same amount of material. In order to reduce conduction losses on the electrode during charging and discharging, a highly conductive bidirectional stretchable electrode has been developed. Other important material parameters like stiffness and bulk resistivity have been optimized to fit the requirements. To realize high power energy harvesting systems, substantial amounts of electroactive polymer material are necessary as well as a smart mechanical and electrical design of the generator. In here we report on different measures to evaluate and improve electroactive polymer materials for energy harvesting by e.g. reducing the defect occurrence and improving the electrode behavior.

  2. Materials design principles of ancient fish armour

    NASA Astrophysics Data System (ADS)

    Bruet, Benjamin J. F.; Song, Juha; Boyce, Mary C.; Ortiz, Christine

    2008-09-01

    Knowledge of the structure-property-function relationships of dermal scales of armoured fish could enable pathways to improved bioinspired human body armour, and may provide clues to the evolutionary origins of mineralized tissues. Here, we present a multiscale experimental and computational approach that reveals the materials design principles present within individual ganoid scales from the `living fossil' Polypterus senegalus. This fish belongs to the ancient family Polypteridae, which first appeared 96 million years ago during the Cretaceous period and still retains many of their characteristics. The mechanistic origins of penetration resistance (approximating a biting attack) were investigated and found to include the juxtaposition of multiple distinct reinforcing composite layers that each undergo their own unique deformation mechanisms, a unique spatial functional form of mechanical properties with regions of differing levels of gradation within and between material layers, and layers with an undetectable gradation, load-dependent effective material properties, circumferential surface cracking, orthogonal microcracking in laminated sublayers and geometrically corrugated junctions between layers.

  3. Materials design principles of ancient fish armour.

    PubMed

    Bruet, Benjamin J F; Song, Juha; Boyce, Mary C; Ortiz, Christine

    2008-09-01

    Knowledge of the structure-property-function relationships of dermal scales of armoured fish could enable pathways to improved bioinspired human body armour, and may provide clues to the evolutionary origins of mineralized tissues. Here, we present a multiscale experimental and computational approach that reveals the materials design principles present within individual ganoid scales from the 'living fossil' Polypterus senegalus. This fish belongs to the ancient family Polypteridae, which first appeared 96 million years ago during the Cretaceous period and still retains many of their characteristics. The mechanistic origins of penetration resistance (approximating a biting attack) were investigated and found to include the juxtaposition of multiple distinct reinforcing composite layers that each undergo their own unique deformation mechanisms, a unique spatial functional form of mechanical properties with regions of differing levels of gradation within and between material layers, and layers with an undetectable gradation, load-dependent effective material properties, circumferential surface cracking, orthogonal microcracking in laminated sublayers and geometrically corrugated junctions between layers. PMID:18660814

  4. Designer protein-based performance materials.

    PubMed

    Kumar, Manoj; Sanford, Karl J; Cuevas, William A; Cuevas, William P; Du, Mai; Collier, Katharine D; Chow, Nicole

    2006-09-01

    Repeat sequence protein polymer (RSPP) technology provides a platform to design and make protein-based performance polymers and represents the best nature has to offer. We report here that the RSPP platform is a novel approach to produce functional protein polymers that have both biomechanical and biofunctional blocks built into one molecule by design, using peptide motifs. We have shown that protein-based designer biopolymers can be made using recombinant DNA technology and fermentation and offer the ability to screen for desired properties utilizing the tremendous potential diversity of amino acid combinations. The technology also allows for large-scale manufacturing with a favorable fermentative cost-structure to deliver commercially viable performance polymers. Using three diverse examples with antimicrobial, textile targeting, and UV-protective agent, we have introduced functional attributes into structural protein polymers and shown, for example, that the functionalized RSPPs have possible applications in biodefense, industrial biotechnology, and personal care areas. This new class of biobased materials will simulate natural biomaterials that can be modified for desired function and have many advantages over conventional petroleum-based polymers. PMID:16961316

  5. Material and methods Only males are designated as type material of the

    E-print Network

    Ribera, Ignacio

    Material and methods Only males are designated as type material of the new species, as although to be indistin- guishable (J. A. Diaz Pazos, pers. comm.). Some type material of species which following the revi

  6. 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 a wide slew of applications from directed self-assembly to biomaterial engineering.

  7. Porous materials. Function-led design of new porous materials.

    PubMed

    Slater, Anna G; Cooper, Andrew I

    2015-05-29

    Porous solids are important as membranes, adsorbents, catalysts, and in other chemical applications. But for these materials to find greater use at an industrial scale, it is necessary to optimize multiple functions in addition to pore structure and surface area, such as stability, sorption kinetics, processability, mechanical properties, and thermal properties. Several different classes of porous solids exist, and there is no one-size-fits-all solution; it can therefore be challenging to choose the right type of porous material for a given job. Computational prediction of structure and properties has growing potential to complement experiment to identify the best porous materials for specific applications. PMID:26023142

  8. COMPUTATIONAL DESIGN OF MULTIPHASE MATERIALS AT THE MESOLEVEL

    Microsoft Academic Search

    Leon Mishnaevsky Jr; Nils Lippmann; Siegfried Schmauder

    2001-01-01

    A concept of optimal design of multiphase materials on the basis of numerical simulation of damage and fracture growth in real and artificial microstructures of the materials is formulated. The suggested procedure includes the following steps: image analysis of the material structure; determination of properties of constituents of the materials; search for regularities or periodicity in the microstructure; simulation of

  9. Design optimization method for compliant mechanisms and material microstructure

    Microsoft Academic Search

    Noboru Kikuchi; Shinji Nishiwaki; Jun S. Ono Fonseca; Emílio C. Nelli Silva

    1998-01-01

    A design methodology based on the global-local modeling method is described along with its application to the design of the optimum layout of compliant mechanisms and the microstructure of composite materials.

  10. 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 wurzitic oxy-nitrides. The wurzite materials also have band gaps less than 3 eV but their surface areas are 2 to 5 m2/g. The thesis explores in detail the changes associated with the gallium coordination as the spinel zinc gallate precursor transforms into the spinel oxy-nitride at 550°C, and further changes into the wurzite oxy-nitride at 850°C are studied through X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, neutron powder diffraction, X-ray absorption spectroscopy and other techniques. We believe that the protocol developed in this thesis opens an avenue for the synthesis of semiconductors having the spinel crystal structure and band gaps engineered to the visible region with potential applications for opto-electronic devices and photocatalytic processes. Though these spinel oxynitrides are interesting, they suffer from vacancies and low surface areas from the high temperature nitridation step. This could be overcome by synthesizing photocatalysts hydrothermally. We proceeded to explore the interactions of Sn2+ 5s orbitals with O 2p orbitals towards hybridizing the valence band. This led to the development of novel visible-light-active Sn2+ - TiO2 and SnOx -- ZnGa2O4 materials. The former catalysts are prepared from the reaction of titanium butoxide and several tin precursors at 80°C in aqueous solutions. Samples synthesized with SnCl2 have lower band gaps (red-shifted to the visible region) with respect to anatase TiO2. The catalysts are isostructural with anatase TiO2 even at the highest loadings of Sn2+. When the precursor is changed to SnCl4, rutile is the predominant phase obtained but no reduction in the band gap is observed. The experiments also indicate the presence of chlorine in the samples, also influencing the optical and catalytic properties as confirmed by comparison to materials prepared using bromide precursors. These catalysts are photocatalytically active for the degradation of organic molecules with rates higher than the standard (P25 TiO2) and also evidenced from the generation of hydroxyl radicals using visible

  11. Materials 4: Design Strategies for Transformative Innovation

    NSDL National Science Digital Library

    2012-12-19

    What can we learn from nature's designs for sustainability? This video compares nature's methods with the industrial era methods of design. It recommends a design strategy based on the connection or relationship between things as a means to achieve transformative innovation for sustainability. This video is part of the Sustainability Learning Suites, made possible in part by a grant from the National Science Foundation. See 'Learn more about this resource' for Learning Objectives and Activities.

  12. Materials by computational design -- High performance thermoelectric materials

    SciTech Connect

    Sales, B. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Lyon, H. [Marlow Industries, Inc., Dallas, TX (United States)

    1997-04-15

    The objective of the project was to utilize advanced computing techniques to guide the development of new material systems that significantly improve the performance of thermoelectric devices for solid state refrigeration. Lockheed Martin Energy Systems, Inc. (LMES) was to develop computational approaches to refine the theory of the thermoelectric effect, establish physical limits, and motivate new materials development. Prior to the project, no major activity in thermoelectric research was visible as an observed limit in experimental data was commonly accepted as a practical limit by the majority of informed opinion in the physics and thermoelectric community. Due to the efforts of the project, new compounds have been isolated which indicates that there is a physical reason to search through the remaining uncharacterized compounds from a top down theoretical approach.

  13. Teaching-Material Design Center: An Ontology-Based System for Customizing Reusable e-Materials

    ERIC Educational Resources Information Center

    Wang, Hei-Chia; Hsu, Chien-Wei

    2006-01-01

    Use of electronic teaching materials (e-material) to support teaching is a trend. e-Material design is therefore an important issue. Currently, most e-material providers offer a package of solutions for different purposes. However, not all teachers and learners need everything from a single package. A preferable alternative is to find useful…

  14. Material transformation designing shape changing interfaces enabled by programmable material anisotropy

    E-print Network

    Ou, Jifei

    2014-01-01

    This thesis takes a material perspective on designing transformable interfaces. The structure of material and mechanical properties such as stiffness, can determine not only its static performances, but also, with the help ...

  15. "Safety Concrete" A Material Designed to Fail

    E-print Network

    Microstructure Binder based on blast furnace slag Slag has a strong tendency to form shrinkage cracks when dried sand #12;Design Variables Composition Variables Processing Variables Binder composition · Slag, OPC strength 1400 psi #12;General Safety Concrete Design 100% slag binder Maximize effect of high

  16. Design for containment of hazardous materials

    SciTech Connect

    Murray, R.C. (Lawrence Livermore National Lab., CA (United States)); McDonald, J.R. (Texas Tech Univ., Lubbock, TX (United States))

    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.

  17. Design and fabrication of new soft magnetic materials

    Microsoft Academic Search

    Ryusuke Hasegawa

    2003-01-01

    A review is given below selecting representative cases in which new soft magnetic materials are fabricated. Examples include bulk amorphous soft magnets, consolidated amorphous ribbon and powder-based magnets and magnetic wires, showing how controllable processes enable us to design new soft magnetic materials. These materials find applications in power electronics, high field magnets, sensors and electronic devices.

  18. SUSTAINABLE INFRASTRUCTURE MATERIAL DESIGN Michael D. Lepech1

    E-print Network

    Lepech, Michael D.

    SUSTAINABLE INFRASTRUCTURE MATERIAL DESIGN Michael D. Lepech1 , Victor C. Li1 , and Gregory A. Keoleian2 1 Advanced Civil Engineering Materials Research Laboratory Department of Civil and Environmental of civil infrastructure systems linking the micron-length scale of material microstructural tailoring

  19. 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.

  20. Bridge : information as material for design

    E-print Network

    Kaijima, Sawako, 1976-

    2005-01-01

    This thesis investigates architectural design as a sensory device that mediates the relationship between the body and the environment. I used a bridge as a site since the body is fully exposed to an open environment, vet ...

  1. 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.

  2. 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…

  3. Computer aided design of multifunctional composite materials

    Microsoft Academic Search

    V. V. Kafarov; I. N. Dorokhov; A. Ramirez; N. I. Kafarova

    1996-01-01

    This paper deal with a multicriterion compromise problem of production of a multifunctional material on the basis of a stochastic composite with several mutually distributed phases. A formal technique for solving this problem is proposed based on the methods of topological feedback, mathematical morphology, percolation theory, and the theory of discrete phase mappings. By way of illustration, this formal technique

  4. Synthesis and Design of Silicide Intermetallic Materials

    SciTech Connect

    Petrovic, J.J.; Castro, R.G.; Vaidya, R.U.; Park, Y.

    1999-05-14

    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 US 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 US processing industries. The program presently has a number of industrial connections, including a CRADA with Johns Manville Corporation targeted at the area of MoSi{sub 2}-based high temperature materials 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. With the Exotherm Corporation, they are developing advanced silicide powders for the fabrication of silicide materials with tailored and improved properties for industrial applications. In October 1998, the authors initiated a new activity funded by DOE/OIT on ``Molybdenum Disilicide Composites for Glass Processing Sensors''. With Accutru International Corporation, they are developing silicide-based protective sheaths for self-verifying temperature sensors which may be used in glass furnaces and other industrial applications. With Combustion Technology Inc., they are developing silicide-based periscope sight tubes for the direct observation of glass melts.

  5. Designing chromonic mesogens for the fabrication of anisotropic optical materials

    NASA Astrophysics Data System (ADS)

    Tam-Chang, Suk-Wah; Huang, Liming; Gyan, Aryal; Seo, Wonewoo; Mahinay, Delfin; Iverson, Isaac K.

    2008-02-01

    Perylene monoimides and diimides have applications as luminescent materials and in organic photovoltaic devices as chromophores and conducting materials. Materials in which these compounds are oriented in a preferred direction will possess useful anisotropic properties that are not attainable from materials in which the compounds are randomly oriented. Anisotropic materials of these compounds can be prepared by taking advantage of the unique properties of chromonic liquid crystals. In this paper we describe the principles for designing perylene monoimides and diimides with desired optical properties and chromonic liquid-crystalline properties. In addition, we demonstrate the fabrication of anisotropic optical materials via organization of these compounds into a lyotropic chromonic liquidcrystalline phase.

  6. 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.

  7. Designing nanostructured magnetic materials by symmetry

    NASA Astrophysics Data System (ADS)

    Cowburn, R. P.; Koltsov, D. K.; Adeyeye, A. O.; Welland, M. E.

    1999-10-01

    We have investigated experimentally the influence of the geometric shape of deep sub-micron nanomagnets on their magnetic properties. We have used high-resolution electron beam lithography to make arrays of nanomagnets in the size range 40-500 nm which had rectangular, triangular, square and pentagonal geometries, corresponding, respectively, to rotational symmetries of order 2, 3, 4 and 5. The parent material was Supermalloy (Ni80Fe14Mo5). We find that an enormously wide range of magnetic properties, including some not found in conventional unstructured materials, can be obtained by using different geometries. We demonstrate that this is because the geometric shape imposes a strong anisotropy field of related symmetry order on the nanomagnet via a recently discovered phenomenon called configurational anisotropy. We show that the coercive field and remanence of these structures is determined directly by this anisotropy.

  8. Designing nanostructured magnetic materials by symmetry

    Microsoft Academic Search

    R. P. Cowburn; D. K. Koltsov; A. O. Adeyeye; M. E. Welland

    1999-01-01

    We have investigated experimentally the influence of the geometric shape of deep sub-micron nanomagnets on their magnetic properties. We have used high-resolution electron beam lithography to make arrays of nanomagnets in the size range 40-500 nm which had rectangular, triangular, square and pentagonal geometries, corresponding, respectively, to rotational symmetries of order 2, 3, 4 and 5. The parent material was

  9. Digital Alchemy for Materials Design and Optimization

    E-print Network

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

    2015-07-17

    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 direct connection between building block attributes and bulk behavior 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 behavior 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.

  10. 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 density. We examine how the results of a design process are contingent upon operating conditions by studying which shapes dissipate energy fastest in a granular gas. We even move to create optimization algorithms for the expressed purpose of material design, by integrating them with statistical mechanics. In all of these cases, we show that turning to machines puts a fresh perspective on materials far from equilibrium. By matching forms to functions, complexities become possibilities, motifs emerge that describe new physics, and the door opens to rational design.

  11. 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.

  12. 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.

  13. 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. 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.

  14. Optimal Design and Scheduling of Unsteady State Material Recovery Networks 

    E-print Network

    Rabie, Arwa H.

    2010-01-14

    methodologies: the first is a hierarchical multi-step methodology developed for the design and scheduling of batch water (material of interest) recycle networks. A new source- double tank-sink arrangement is introduced to overcome the limitation of samecycle...

  15. A Design for Class Testing Mathematics Textbook Materials

    ERIC Educational Resources Information Center

    Zahn, Karl G.

    1972-01-01

    A study designed to test the teachability of new textbook material used small group discussions and daily quizzes as procedures in classroom organization; results showed that students gained significantly in mathematical knowledge. (DT)

  16. 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.

  17. Optimum material design of minimum structural compliance under seepage constraint

    Microsoft Academic Search

    Shengli Xu; Gengdong Cheng

    2010-01-01

    In filtration and chemical engineering industry the load carrying capacity and seepage performances are very important for\\u000a a successful filter design. We study a two-scale structural design optimization problem to minimize structural compliance\\u000a under given seepage flow rate and material porosity constraints. Structural size, shape and topology are given because of\\u000a other functional requirements. Structural material used is macro homogeneous

  18. Designing Radiation Resistance in Materials for Fusion Energy

    SciTech Connect

    Zinkle, Steven J [University of Tennessee (UT)] [University of Tennessee (UT); Snead, Lance Lewis [ORNL] [ORNL

    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.

  19. Topological design of structures and composite materials with multiobjectives

    Microsoft Academic Search

    Niek de Kruijf; Shiwei Zhou; Qing Li; Yiu-Wing Mai

    2007-01-01

    This paper studies the influence of heat conduction in both structural and material designs in two dimensions. The former attempts to find the optimal structures with the maximum stiffness and minimum resistance to heat dissipation and the latter to tailor composite materials with effective thermal conductivity and bulk modulus attaining their upper limits like Hashin–Shtrikman and Lurie–Cherkaev bounds. In the

  20. 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…

  1. Design of underfill materials for lead free flip chip applications

    Microsoft Academic Search

    Saketh Mahalingam; K. Goray; A. Joshi

    2004-01-01

    The reliability of flip chips (FC) is enhanced several orders of magnitude by the introduction of an underfill material between the chip and the substrate. The design of such underfill materials is not trivial due to the varied failure mechanisms that occur in the underfilled configuration. Reliability of underfilled flip chips not only depends on the thermo-mechanical properties of the

  2. A conceptual design method for structures and structural materials

    NASA Astrophysics Data System (ADS)

    Kosaka, Iku

    To this point in time, most topology design formulations have been applied strictly to applications involving the layout of linear elastic materials. An objective of this dissertation is to extend topology design optimization to structures involving general, elastic and inelastic material behaviors. The desired results of variable topology material layout computations are stable, discrete and optimal material arrangements throughout the design domain. Such layout designs of general materials are achieved herein using a continuous topology optimization formulation based on classical Voigt and Reuss mixing rules, and hybrid combinations thereof. The continuous topology optimization formulation is coupled with novel spatial filtering to solve the problem of checkerboarding instabilities, and spatial symmetry reduction methods to enforce symmetries and reduce the size of the optimization problem. The proposed methods are first applied to compliance minimization and eigenvalue tailoring problems involving linear elastic material behaviors. Uniqueness, stability, interpretability, and manufacturability issues of the formulation are studied and noted for the compliance minimization problem. Then, a software integration scheme involving the usage of general purpose commercial FEM codes for continuum linear elastic structural topology optimization is briefly discussed. Topology design software which makes use of commercial FEM codes and the proposed topology design optimization formulation is developed and demonstrated on practical engineering problems. The proposed topology formulation is also extended to other novel engineering applications such as the design of structures with compliant mechanisms and the design of high-performance structural composites. In these novel classes of problems, high quality material layout solutions are obtained. Finally, structural topology optimization problems involving inelastic material behaviors are formulated and accurate algorithms for incremental topology design sensitivity analysis of energy type functionals are developed. The consistency between the structural topology design formulation and the developed sensitivity analysis algorithms is established on structural topology problems separately involving linear elastic materials, elastoplastic materials, and viscoelastic materials. The performance of the proposed framework is demonstrated by solving three topology optimization problems to maximize the limit strength of elastoplastic structures as well as to maximize the mechanical damping of viscoelastic structures.

  3. Center for Intelligent Fuel Cell Materials Design

    SciTech Connect

    Santurri, P.R., (Chemsultants International); Hartmann-Thompson, C.; Keinath, S.E. (Michigan Molecular Inst.)

    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 provides a key element for the United States: 1) to transition the country from a fossil fuel based energy economy to a renewable energy based economy, and 2) to reduce our dependence on foreign oil. Developments of this program will serve as an important step toward continuing PEMFC technology and ultimately the broad-based commercial availability of this technology and its benefits.

  4. Designing new materials from wheat protein.

    PubMed

    Woerdeman, Dara L; Veraverbeke, Wim S; Parnas, Richard S; Johnson, Dave; Delcour, Jan A; Verpoest, Ignaas; Plummer, Christopher J G

    2004-01-01

    We recently discovered that wheat gluten could be formed into a tough, plasticlike substance when thiol-terminated, star-branched molecules are incorporated directly into the protein structure. This discovery offers the exciting possibility of developing biodegradable high-performance engineering plastics and composites from renewable resources that are competitive with their synthetic counterparts. Wheat gluten powder is available at a cost of less than dollars 0.5/lb, so if processing costs can be controlled, an inexpensive alternative to synthetic polymers may be possible. In the present work, we demonstrate the ability to toughen an otherwise brittle protein-based material by increasing the yield stress and strain-to-failure, without compromising stiffness. Water absorption results suggest that the cross-link density of the polymer is increased by the presence of the thiol-terminated, star-branched additive in the protein. Size-exclusion high performance liquid chromatography data of molded tri-thiol-modified gluten are consistent with that of a polymer that has been further cross-linked when compared directly with unmodified gluten, handled under identical conditions. Remarkably, the mechanical properties of our gluten formulations stored in ambient conditions were found to improve with time. PMID:15244439

  5. Optimal experimental design for estimating thermal properties of composite materials

    Microsoft Academic Search

    R. Taktak; J. V. Beck; E. P. Scott

    1993-01-01

    Design of optimal transient experiments is needed for the efficient estimation of thermal conductivity and volumetric heat capacity of composite materials. One criterion for optimal experiments is the minimization of the area (or volume) of the confidence region. The experimental designs are transient and involve both finite and semi-finite geometries with finite duration heating. Two cases are considered for the

  6. Design criteria for vault automation in special nuclear material storage

    Microsoft Academic Search

    W. T. McDuffee; W. R. Hamel; L. B. Shappert; A. S. Pruitt

    1978-01-01

    Design criteria for safeguards benefits derived for candidate designs of automated special nuclear material storage vault systems are developed. These are based on the safeguards benefit evaluation methodology reported earlier that is used in establishing performance standards for each element of the safeguards functions. Numerical values between 1 and 10 are obtained which minimize the effect of personal preferences or

  7. A design method for superconducting MRI magnets with ferromagnetic material

    Microsoft Academic Search

    Huawei Zhao; Stuart Crozier

    2002-01-01

    The emphasis of this work is on the optimal design of MRI magnets with both superconducting coils and ferromagnetic rings. The work is directed to the automated design of MRI magnet systems containing superconducting wire and both 'cold' and 'warm' iron. Details of the optimization procedure are given and the results show combined superconducting and iron material MRI magnets with

  8. Structure-based design of functional amyloid materials.

    PubMed

    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

    2014-12-31

    Amyloid fibers, once exclusively associated with disease, are acquiring utility as a class of biological nanomaterials. Here 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. 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. PMID:25474758

  9. 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.

  10. Designing optical elements from isotropic materials by using transformation optics

    SciTech Connect

    Schmiele, Martin; Varma, Vineeth S.; Rockstuhl, Carsten; Lederer, Falk [Institute of Solid State Theory and Optics, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

    2010-03-15

    By taking advantage of a conformal mapping technique, we propose designs for various optical elements such as directional antennas, flat lenses, or bends. In contrast to most of the existing design approaches, the elements can be implemented with isotropic materials, thus strongly facilitating their fabrication. We furthermore generalize the concept and show that under certain conditions previously suggested devices consisting of anisotropic materials may be replaced by isotropic ones using an appropriate transformation. The designs are double-checked by full-wave simulations. A comparison with their anisotropic counterparts reveals a similar performance.

  11. 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 materials, first as discrete actuators for vibration isolation, and second as structurally-distributed sensor/actuators for active acoustic control.

  12. Materials of interaction : responsive materials in the design of transformable interactive surfaces

    E-print Network

    Coelho, Marcelo

    2008-01-01

    Materials that embody computational properties are reshaping the ways in which we design, interact and communicate. This thesis looks at the topic of form transformation and how to bring the programmability and versatility ...

  13. Ceramic transactions: Ferroic materials - design, preparation, and characteristics. Volume 43

    SciTech Connect

    Bhalla, A.S.; Nair, K.M.; Lloyd, I.K.; Yanagida, H.; Payne, D.A. [eds.

    1994-12-31

    Ferroic materials have found application in both sensing and actuating devices such as detectors, high- and low-frequency transducers, capacitors, optical modulators, shutters, and photorestructive and electrostrictive devices. The application areas of ferroics in single-crystal, bulk ceramics, thin-film, and composite forms have been expanding quite rapidly in recent years. As a result, new materials design and fabrication techniques are needed to satisfy the new emerging applications of these smart materials and structures. With the drive of new national and international initiatives in the areas of advanced materials and technology, smart structures and systems, environmental beneficiation programs, etc., it is highly desirable to review and project the direction in materials design, preparation, and sensing properties. The decision of the American Ceramic Society to organize the first PAC RIM meeting, held in Honolulu, HI, November 7-10, 1993, gave an opportunity to review these topics in depth by bringing together leading researchers and device engineers from universities, national laboratories, and industry. This volume is a collection of selected papers from three closely related symposia on ferroelectric thin films, materials for intelligent/smart systems and adaptive structures, and processing of thin films. The papers have been organized into three broad categories: Thin Films: Preparation and Characteristics, Design and Properties of Materials, and sensor Characteristics. All the papers were reviewed through a peer review process.

  14. Design and Materials The Design area is a rapidly growing research area aimed at furthering the development of

    E-print Network

    Calgary, University of

    Design and Materials Design The Design area is a rapidly growing research area aimed at furthering the development of competitive products and systems. Research in this department focuses on design theories, design methodologies

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

    Microsoft Academic Search

    Talat S. Rahman

    2009-01-01

    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

  16. 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.

  17. MEMS Switch Material Dependency on Designing a Reconfigurable Antenna

    Microsoft Academic Search

    A. H. M. Zahirul Alam; M. R. Islam; Sheroz Khan; B. M. Azlani; M. M. Bt. Abdul Razak

    2006-01-01

    We report on reconfigurable antenna performance using RF MEMS switches dependency on material used for MEMS structure. Teflon as a MEMS structural material gives triple-band antenna operation at 17.21, 23.54 and 29.27 GHz with return loss -12.04, -19.37 and -17.34 dB, respectively. The design is performed using 3D electromagnetic simulators considering ideal MEMS switches. There is no shift of resonance

  18. Constitutive Modeling of Photostrictive Materials and Design Optimization of Microcantilevers

    Microsoft Academic Search

    Quantian Luo; Liyong Tong

    2009-01-01

    This article presents constitutive models for photo-induced strains in photostrictive materials and an optimal design of microcantilevers driven by light illumination. Behaviors of photo-induced strains in semiconductors and polymeric materials are reviewed first, and then new phenomenological constitutive models are developed that depict two distinctive features of photo-induced strain profile: (a) dependence on variation of light intensity which decreases with

  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. 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.

  2. The damage, repair and design of fiber composite structural materials

    SciTech Connect

    Chu, Fa-De Jack.

    1992-01-01

    Three aspects of the repair of fiber reinforced composite materials were examined in this study. First, the in-plane compression damage of four typical fiber composite materials was studied, and different repair strategies were explored. Second, an optimum composite sheet design for least damaged by buckling and easiest to repair was studied. Third, anhydride-cured epoxy adhesive and E-glass fibers/vinyl ester matrix, which is critical to the quality of the repair, was investigated. For none of the four typical fiber composite materials subjected to in-plane compression do all of the load carrying fibers break, and those do are usually in easily removal layers. Moreover, the behavior of each material was relatively consistent. As a result, a new repair strategy is proposed in which nor more of the load-carrying fibers are removed from the damage zone than are broken. For the two laminated materials, a transition in failure mode form tensile to shear was found as the effective gage length of the specimen decreased. This suggests that the composite structure can be designed to relieve the applied can be designed to relieve the applied load in desired locations and with benign failure modes. In the second part, ten composite materials with different fiber stacking sequences were subjected to in-plane compression. Three failure modes were dominant: shear, delamination buckling, and flexural failure. The volume of damage occurring in the 0[degrees]-fiber plies decreased lamination buckling failure. With respect to the amount of damage and repair strength recovery, it is best to have the composite structure designed to fail in delamination buckling when failure is inevitable. In the third part, model system were used to simulate the interfacial region between adhesive and adherent. These involved curing the adhesive against FTIR-ATR plate and against adherent material ground to a fine powder to greatly increase its surface area.

  3. A Loop Material Flow System Design for Automated Guided Vehicles

    E-print Network

    Dessouky, Maged

    Abstract We develop an exact integer programming formulation to design a loop material ow system for unit of LP/IP routines, analyzing the mathemati- cal properties of the problem, and developing an intelligent branch and bound solution procedure. Keywords and phrases: Facilities Planning, AGVS, Integer Programming

  4. 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.

  5. Design of piezocomposite materials and piezoelectric transducers using topology optimization

    Microsoft Academic Search

    Emilio Carlos Nelli Silva

    1998-01-01

    Piezoelectric materials are widely used in electromechanical sensors and actuators, in electronic equipment as resonators, and in acoustic applications as ultrasonic transducers and hydrophones for generating and detecting sound waves. Their development has been based on the use of simple analytical models, test of prototypes, and analysis by the finite element method (FEM), usually limiting their design to a parametric

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

    E-print Network

    Designed amyloid fibers as materials for selective carbon dioxide capture Dan Lia,b,c,1 , Hiroyasu demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence

  7. 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.

  8. Designing ECM-mimetic Materials Using Protein Engineering

    PubMed Central

    Cai, Lei; Heilshorn, Sarah C.

    2014-01-01

    The natural extracellular matrix (ECM), with its multitude of evolved cell-instructive and cell-responsive properties, provides inspiration and guidelines for the design of engineered biomaterials. One strategy to create ECM-mimetic materials is the modular design of protein-based engineered ECM (eECM) scaffolds. This modular design strategy involves combining multiple protein domains with different functionalities into a single, modular polymer sequence, resulting in a multifunctional matrix with independent tunability of the individual domain functions. These eECMs often enable decoupled control over multiple material properties for fundamental studies of cell-matrix interactions. In addition, since the eECMs are frequently composed entirely of bioresorbable amino acids, these matrices have immense clinical potential for a variety of regenerative medicine applications. This brief review demonstrates how fundamental knowledge gained from structure-function studies of native proteins can be exploited in the design of novel protein-engineered biomaterials. While the field of protein-engineered biomaterials has existed for over 20 years, the community is only now beginning to fully explore the diversity of functional peptide modules that can be incorporated into these materials. We have chosen to highlight recent examples that either (1) demonstrate exemplary use as matrices with cell-instructive and cell-responsive properties or (2) demonstrate outstanding creativity in terms of novel molecular-level design and macro-level functionality. PMID:24365704

  9. 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 simultaneously, over a wide range of relative densities, greatly expanding the property space of available materials with a pragmatic manufacturable structure. A variety of other novel and previously studied ordered foam topologies are also presented that are largely representative of the spectrum of performance of such materials, shedding insight into the behavior of all cellular materials.

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

    SciTech Connect

    Shappert, L.B.; Bowman, S.M. [Oak Ridge National Lab., TN (United States); Arnold, E.D. [Lockheed Martin Energy Systems, Oak Ridge, TN (United States)] [and others

    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.

  11. Thermal design of composite material high temperature attachments

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An evaluation has been made of the thermal aspects of utilizing advanced filamentary composite materials as primary structures on the shuttle vehicle. The technical objectives of this study are to: (1) establish and design concepts for maintaining material temperatures within allowable limits at TPS attachments and or penetrations applicable to the space shuttle; and (2) verify the thermal design analysis by testing selected concepts. Specific composite materials being evaluated are boron epoxy, graphite/epoxy, boron polyimide, and boron aluminum; graphite/polyimide has been added to this list for property data identification and preliminary evaluation of thermal design problems. The TPS standoff to composite structure attachment over-temperature problem is directly related to TPS maximum surface temperature. To provide a thermally comprehensive evaluation of attachment temperature characteristics, maximum surface temperatures of 900 F, 1200 F, 1800 F, 2500 F and 3000 F are considered in this study. This range of surface temperatures and the high and low maximum temperature capability of the selected composite materials will result in a wide range of thermal requirements for composite/TPS standoff attachments.

  12. Tunable structural color in organisms and photonic materials for design of bioinspired materials

    NASA Astrophysics Data System (ADS)

    Fudouzi, Hiroshi

    2011-12-01

    In this paper, the key topics of tunable structural color in biology and material science are overviewed. Color in biology is considered for selected groups of tropical fish, octopus, squid and beetle. It is caused by nanoplates in iridophores and varies with their spacing, tilting angle and refractive index. These examples may provide valuable hints for the bioinspired design of photonic materials. 1D multilayer films and 3D colloidal crystals with tunable structural color are overviewed from the viewpoint of advanced materials. The tunability of structural color by swelling and strain is demonstrated on an example of opal composites.

  13. 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 stiffness is still in its infancy, and the development of smart materials to assist in investigating the active control of stiffness and in the construction of robotic fish-like devices is a key challenge for the near future.

  14. 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

  15. 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.

  16. 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

    ...Waterway (SNWW) Ocean Dredged Material Disposal Site Designation AGENCY: Environmental...designate four new Ocean Dredged Material Disposal Site(s) (ODMDS) located offshore of Texas for the disposal of dredged material from the...

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

    SciTech Connect

    Germann, Timothy C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    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.

  18. 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.

  19. 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.

  20. 36 CFR 401.5 - Control and supervision of materials, design, and building.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Control and supervision of materials, design, and building. 401.5 Section 401.5 Parks... § 401.5 Control and supervision of materials, design, and building. The Commission controls the design...

  1. New Micro Structural Design Concept for Polycrystalline Composite Materials

    Microsoft Academic Search

    A. N. RYBJANETS; A. V. NASEDKIN; A. V. TURIK

    2004-01-01

    A new concept of microstructural designing of polymer-free polycrystalline composite materials is offered. The concept based on controllable substitution during composite formation of separate crystallites making a polycrystal by pores, crystallites with other composition and\\/or structure or amorphous substances with preliminary FEM modeling of polycrystalline composite properties. A line of precursor small-scale production technologies and polycrystalline composites with unique and

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

    SciTech Connect

    Ohtani, Yoshimutsu; Yoshimura, Fumikatsu; Hatakeyama, Iwao [NTT Interdisciplinary Research Labs., Tokai, Ibaraki (Japan); Ishii, Yoshikazu [NTT Interdisciplinary Research Labs., Musashino, Tokyo (Japan)

    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.

  3. 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.

  4. 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

  5. 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

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

    SciTech Connect

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

    2013-04-30

    For many decades, various radiation detecting material have been extensively researched, to find a better material or mechanism for radiation sensing. Recently, there is a growing need for a smaller and effective material or device that can perform similar functions of bulkier Geiger counters and other measurement options, which fail the requirement for easy, cheap and accurate radiation dose measurement. Here arises the use of thin film chalcogenide glass, which has unique properties of high thermal stability along with high sensitivity towards short wavelength radiation. The unique properties of chalcogenide glasses are attributed to the lone pair p-shell electrons, which provide some distinctive optical properties when compared to crystalline material. These qualities are derived from the energy band diagram and the presence of localized states in the band gap. Chalcogenide glasses have band tail states and localized states, along with the two band states. These extra states are primarily due to the lone pair electrons as well as the amorphous structure of the glasses. The localized states between the conductance band (CB) and valence band (VB) are primarily due to the presence of the lone pair electrons, while the band tail states are attributed to the Van der Waalâ??s forces between layers of atoms [1]. Localized states are trap locations within the band gap where electrons from the valence band can hop into, in their path towards the conduction band. Tail states on the other hand are locations near the band gap edges and are known as Urbach tail states (Eu). These states are occupied with many electrons that can participate in the various transformations due to interaction with photons. According to Y. Utsugi et. al.[2], the electron-phonon interactions are responsible for the generation of the Urbach tails. These states are responsible for setting the absorption edge for these glasses and photons with energy near the band gap affect these states. We have 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 â?? 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.

  7. Microstructure Informatics Successful design and development of new advanced materials with desired performance

    E-print Network

    Li, Mo

    , because a rigorous treatment of the material internal structure requires a very high dimensional of materials databases that allow quantitative comparison of material structures. Georgia Tech capabilitiesMicrostructure Informatics Successful design and development of new advanced materials with desired

  8. 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 predictions of performances of masks that would be made from alternative materials chosen because the wavelength dependences of their extinction coefficients and their indices of refraction are such that that the optical-density and phase profiles of masks made from these materials can be expected to vary much less with wavelength than do those of masks made from HEBS glass. The alternative materials considered thus far include some elemental metals such as Pt and Ni, metal alloys such as Inconel, metal nitrides such as TiN, and dielectrics such as SiO2. A mask as now envisioned would include thin metal and dielectric films having stepped or smoothly varying thicknesses (see figure). The thicknesses would be chosen, taking account of the indices of refraction and extinction coefficients, to obtain an acceptably close approximation of the desired spatial transmittance profile with a flat phase profile

  9. 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.

  10. High permittivity material selection for design of optimum Hk VDMOS

    NASA Astrophysics Data System (ADS)

    Naugarhiya, Alok; Kondekar, Pravin N.

    2015-07-01

    In this paper, we have proposed a novel approach for the selection of high permittivity (Hk) material for the optimum design of Hk vertical double diffused MOS (VDMOS). The optimum design parameters under consideration are geometry, doping concentration and breakdown voltage (BV). We have investigated reliability and sensitivity of the Hk VDMOS using BV and figure-of-merit (FOM) analysis, respectively. Further, we have compared results of Hk VDMOS with superjunction (SJ) VDMOS and conventional VDMOS. The observation clarifies that the higher doping concentration can be used in the drift region of Hk n-pillar when comparing with a SJ VDMOS and conventional VDMOS without affecting the BV. Due to this, the area-specific ON-resistance (Ron A) of the Hk VDMOS is less as compared to the SJ VDMOS and conventional VDMOS with the same BV. Using FOM, we can select the Hk material for maximum doping concentration and maximum BV with lowest Ron A for specific design application of Hk VDMOS.

  11. 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

  12. Material Discovery and Design with Dynamic Charge Reactive Potentials

    NASA Astrophysics Data System (ADS)

    Sinnott, Susan

    2015-03-01

    Atomic scale computational simulations of multi-phase systems is increasingly important as our ability to simulate nanometer-sized systems becomes routine. The recently developed charge optimized many body potential (COMB) potentials have significantly enhanced our ability to carry out atomic-scale simulations of heterogeneous material systems. The formalism of this potential combines variable charge electrostatic interactions with a classical analytical bond-order potential. It therefore has the capacity to adaptively model metallic, covalent, ionic, and van der Waals bonding within the same simulation cell and dynamically determine the charges on individual atoms according to the local environment. The utility of the COMB potentials is illustrated for materials design and discovery by exploring the structure, stability, mechanical properties, and thermal properties of intermetallic systems and oxide-metal interfaces. They are also used to address key questions associated with corrosion, thin film growth, and heterogeneous catalysis.

  13. 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.

  14. 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.

  15. 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

  16. 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 ?-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 materials, such as energy transfer, charge separation, and exciton-plasmon coupling, a series of novel nanophotonic devices could be achieved for light signal manipulation. First, we provide an overview of the research evolution of organic nanophotonics, which arises from attempts to explore the photonic potentials of low-dimensional structures assembled from organic molecules. Then, recent advances in this field are described from the viewpoints of molecules, materials, and devices. Many kinds of optofunctional molecules are designed and synthesized according to the demands in high luminescence yield, nonlinear optical response, and other optical properties. Due to the weak interactions between these molecules, numerous micro- or nanostructures could be prepared via self-assembly or vapor-deposition, bringing the capabilities of light transport and confinement at the wavelength scale. The above advantages provide great possibilities in the fabrication of organic nanophotonic devices, by rationally combining these functional components to manipulate light signals. Finally, we present our views on the current challenges as well as the future development of organic nanophotonic materials and devices. This Account gives a comprehensive understanding of organic nanophotonics, including the design and fabrication of organic micro- or nanocrystals with specific photonic properties and their promising applications in functional nanophotonic components and integrated circuits. PMID:25343682

  17. 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 final product, and present a major bottleneck. We propose to solve the microalgae dewatering problem in the context of controlling colloidal stability, where inter-algal potential is tuned via surface engineering of novel coagulation agents. We report here a nanoparticle-pinched polymer brush design that combines two known colloidal destabilization agents (e.g., nanoparticle and polymer) into one system, and allows the use of an external field (e.g., magnetic force) to not only modulate inter-algae pair potentials, but also facilitate retrieval of the coagulation agents to be reused after algal oil extraction. We will discuss our extensive data on the preparation of well-defined nanoparticle-pinched polymer brushes, their structure-dependent coagulation performance on both fresh water and marine microalgae species, and their re-suability for continuous cycles of microalgae farming and harvesting.

  18. Molding and filament winding of spatially graded material properties through computational design

    E-print Network

    Gonzalez Uribe, Carlos David

    2014-01-01

    Three-dimensional printing and computational design have enabled designers to spatially vary material properties in objects. Nevertheless, this technology has current limitations that include material durability, cost and ...

  19. Designing intermediate-range order in amorphous materials.

    PubMed

    Martin, James D; Goettler, Stephen J; Fossé, Nathalie; Iton, Lennox

    2002-09-26

    Amorphous materials are commonly understood to consist of random organizations of molecular-type structural units. However, it has long been known that structural organizations intermediate between discrete chemical bonds and periodic crystalline lattices are present even in liquids. Numerous models--including random networks and crystalline-type structures with networks composed of clusters and voids--have been proposed to account for this intermediate-range order. Nevertheless, understanding and controlling structural features that determine intermediate-range order in amorphous materials remain fundamental, yet presently unresolved, issues. The most characteristic signature of such order is the first peak in the total structure factor, referred to as the first sharp diffraction peak or 'low Q' structure. These features correspond to large real-space distances in the materials, and understanding their origin is key to unravelling details of intermediate-range order. Here we employ principles of crystal engineering to design specific patterns of intermediate-range order within amorphous zinc-chloride networks. Using crystalline models, we demonstrate the impact of various structural features on diffraction at low values of Q. Such amorphous network engineering is anticipated to provide the structure/property relationships necessary to tailor specific optical, electronic and mechanical properties. PMID:12353031

  20. 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

  1. Materials for Consideration in Standardized Canister Design Activities.

    SciTech Connect

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

    2014-10-02

    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 establish corrosion rates and component lifetimes. Finally, it is unlikely that the aluminum-based neutron absorber materials that are commonly used in existing DPCs would survive for 10,000 years in disposal environments, because the aluminum will act as a sacrificial anode for the steel. We recommend additional testing of borated and Gd-bearing stainless steels, to establish general and localized corrosion resistance in repository-relevant environmental conditions.

  2. 78 FR 37759 - Ocean Dumping; Atchafalaya-West Ocean Dredged Material Disposal Site Designation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-24

    ...Atchafalaya-West Ocean Dredged Material Disposal Site Designation AGENCY: Environmental...Atchafalaya-West Ocean Dredged Material Disposal Site pursuant to the draft EIS...River Bar Channel Ocean Dredged Material Disposal Site Pursuant to Section 102(c)...

  3. Optical sensor designs for the detection of cracks in optical materials

    Microsoft Academic Search

    J. R. Hodor; H. J. Decker Jr.; J. Barney

    1989-01-01

    Four basic sensor designs for detecting cracks in optical materials have been conceived. All of the designs rely upon the fact that a crack's cleavage in the material provides a total or nearly total internal reflection boundary. The basic designs use a radiation source to which the material is transmissive and a video camera which is sensitive to the source's

  4. Optimizing multifunctional materials: Design of microstructures for maximized stiffness and fluid permeability

    Microsoft Academic Search

    James K. Guest; Jean H. Prévost

    2006-01-01

    Topology optimization is used to systematically design periodic materials that are optimized for multiple properties and prescribed symmetries. In particular, mechanical stiffness and fluid transport are considered. The base cell of the periodic material serves as the design domain and the goal is to determine the optimal distribution of material phases within this domain. Effective properties of the material are

  5. Interfacial Properties and Design of Functional Energy Materials

    SciTech Connect

    Sumpter, Bobby G [ORNL; Liang, Liangbo [ORNL; Nicolai, Adrien [Rensselaer Polytechnic Institute (RPI); Meunier, V. [Rensselaer Polytechnic Institute (RPI)

    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 process of materials discovery by providing atomic level understanding of physicochemical phenomena and for making predictions of trends. In particular, this approach can provide understanding, prediction and exploration of new materials and conditions before they are realized in the lab, to illuminate connections between experimental observations, and help identify new materials for targeted synthesis. Toward this end, Density Functional Theory (DFT) can provide a suitable computational framework for investigating the inter- and intramolecular bonding, molecular conformation, charge and spin configurations that are intrinsic to self-assembly of molecules on substrates. This Account highlights recent advances in using an integrated approach based on DFT and scanning probe microscopy [STM(s), AFM] to study/develop electronic materials formed from the self-assembly of molecules into supramolecular or polymeric architectures on substrates. Here it is the interplay between molecular interactions and surface electrons that is used to control the final architecture and subsequent bulk properties of the two-dimensional patterns/assemblies. Indeed a rich variety of functional energy materials become possible.

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

    SciTech Connect

    NONE

    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.

  7. Design and Operation of Membrane Microcalorimeters for Thermal Screening of Highly Energetic Materials 

    E-print Network

    Carreto Vazquez, Victor 1976-

    2010-12-07

    -scale calorimetry to the screening of highly energetic materials. The prototypes presented here were designed using computer assisted design and finite element analysis tools. The design parameters were set to satisfy the requirements of a sensor that can...

  8. 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 Al2O3--MgO--CaO ternary system. Materials selection criteria for reinforcement materials was based on improved high temperature stability, increased strength, reduced thermal expansion mismatch, low thermal conductivity and increasing wear resistance. The reinforcement phases selected for this investigation are zircon (ZrSiO4), zirconia (ZrO2), spinel (MgAl2O4) and dead burnt magnesia (MgO). Batches of the formulations were tested for thermal conductivity, wear resistance and mechanical strength. Relative rankings of the formulations against commercial products indicate improved or similar performance with increased maximum temperature limits and improved thermal insulating power. The new cement formulations proved to exhibit superior high temperature stability with an increasing volume fraction of high temperature oxides. The addition of reinforcement aggregates and powder sizing to offset the loss of strength. The room temperature compression strength and wear resistance of the optimized formulations exceeded the properties of conventional refractory, brick and castable cement tested concurrently.

  9. Evaluation of critical materials in five additional advance design photovoltaic cells

    Microsoft Academic Search

    S. A. Smith; R. L. Watts; P. Martin; W. E. Gurwell

    1981-01-01

    Potential material supply constraints due to the large scale deployment of five advanced photovoltaic (PV) cell designs were identified and strategies to reduce the impacts of these production capacity limitations and potential future material are suggested. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large scale use of

  10. Materials selection in micromechanical design: an application of the Ashby approach

    Microsoft Academic Search

    V. T. Srikar; S. Mark Spearing

    2003-01-01

    The set of materials available to microsystems designers is rapidly expanding. Techniques now exist to introduce and integrate a large number of metals, alloys, ceramics, glasses, polymers, and elastomers into microsystems, motivating the need for a rational approach for materials selection in microsystems design. As a step toward such an approach, we focus on the initial stages of materials selection

  11. Simulation and design optimization of wave propagation in heterogeneous materials

    E-print Network

    Saà-Seoane, Joel

    2014-01-01

    Propagation of waves through heterogeneous structured materials has been the focus of considerable research in recent years. These materials consist of quasi periodic geometries combining two or more piecewise homogeneous ...

  12. Fab trees for designing complex 3D printable materials

    E-print Network

    Wang, Ye, M. Eng. Massachusetts Institute of Technology

    2013-01-01

    With more 3D printable materials being invented, 3D printers nowadays could replicate not only geometries, but also appearance and physical properties. On the software side, the tight coupling between geometry and material ...

  13. Geothermal turbines-materials evaluation and design aspects

    Microsoft Academic Search

    S. Toney; M. Cohen; O. Tuncel

    1982-01-01

    A considerable number of on-site material test programs have been conducted at different geothermal sites to provide a data base which permits characterization of materials used, or considered potentially useful, for geothermal turbine applications. These programs have included the exposure of test specimens of different materials to geothermal steam from a steam resource, as at the Geysers, or in flashed

  14. Material design method for the functionally graded cemented carbide tool

    Microsoft Academic Search

    Toshio Nomura; Hideki Moriguchi; Keiichi Tsuda; Kazutaka Isobe; Akihiko Ikegaya; Kiyoko Moriyama

    1999-01-01

    The aim of this study is to apply the concept of functionally graded materials (FGMs) to tool materials and to develop high-performance cutting tools. The requirement of the graded structure is that the surface is highly wear resistant cermet, and the inside is tough cemented carbide. Compressive residual stress was introduced to the material surface by grading the composition. To

  15. A knowledge-based system for materials selection in mechanical engineering design

    Microsoft Academic Search

    S. M Sapuan

    2001-01-01

    This paper studies various work on the development of computerized material selection system. The importance of knowledge-based system (KBS) in the context of concurrent engineering is explained. The study of KBS in material selection in an engineering design process is described. The development in materials databases, which sometimes serve as material selection packages, is also discussed. The use of KBS

  16. Design Guidelines for the Development of Digital Nutrigenomics Learning Material for Heterogeneous Target Groups

    NSDL National Science Digital Library

    Maria C. Busstra (Wageningen University Nutrition, Metabolism, and Genomics Group, Division of Human Nutrition)

    2007-03-01

    Nutritional genomics, or nutrigenomics, can be considered as the combination of molecular nutrition and genomics. This study describes digital nutrigenomics learning material suitable for students from various backgrounds and provides design guidelines for the development of the learning material.

  17. Category theory based solution for the building block replacement problem in materials design

    E-print Network

    Giesa, Tristan

    An important objective in materials design is to develop a systematic methodology for replacing unavailable or expensive material building blocks by simpler and abundant ones, while maintaining or improving the functionality ...

  18. Systematising EAP Materials Development: Design, Evaluation and Revision in a Thai Undergraduate Reading Course 

    E-print Network

    Sudajit-apa, Melada

    2008-01-01

    Materials design and evaluation have been regarded as inseparable processes for a systematic approach to materials development. But much less attention has been paid to the role and process of revision. This study reports ...

  19. 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 and the derivation of first-order design sensitivities to increase computational efficiency. Inspired by honeycomb materials, a new method of discretizing the material design domain into unit cells with non-simple connectivity is proposed as a way of increasing the solution space of the topology optimization problem. Finally, these methods are used in the meta-material design process to identify several candidate meta-material geometries from a polycarbonate base material for the shear layer of the non-pneumatic wheel; notable geometries include an 'x'-like geometry, a bent column-like geometry identified previously as a bristle, and, remarkably, an auxetic honeycomb geometry. This is the first reported result demonstrating the auxetic honeycomb geometry to be a minimum weight structure in shear loading where a general topology optimization method was used.

  20. A Schematic Method for Sustainable Material Selection of Toxic Chemicals in Design and Manufacturing

    E-print Network

    Yuan, Chris Yingchun; David Dornfeld

    2010-01-01

    products in both design and manufacturing processes. In this paper, a schematic methodMethod for Sustainable Material Selection of Toxic Chemicals in Design and Manufacturing Toxic chemicals used in product

  1. 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

  2. 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…

  3. Optimal shape design as a material distribution problem

    Microsoft Academic Search

    M. P. Bendsøe

    1989-01-01

    Shape optimization in a general setting requires the determination of the optimal spatial material distribution for given loads and boundary conditions. Every point in space is thus a material point or a void and the optimization problem is a discrete variable one. This paper describes various ways of removing this discrete nature of the problem by the introduction of a

  4. Design of Nanoscale Materials Using Silica-Coated Metal Nanocolloids

    Microsoft Academic Search

    Luis M. Liz-Marzán

    This chapter deals with the synthesis and properties of nanostructures based on the assembly of composite nanoparticles with core-shell morphology. The interest of such nanosystems relies mostly on the combination of the properties of the two (or more) materials involved, with the important feature that one of the materials (the shell) will determine the surface properties of the particles, while

  5. 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.

  6. Computational Design of Novel, Radiation Resistant Fusion Materials

    SciTech Connect

    Kubota, A; Caturla, M J; Wirth, B D; Latkowski, J

    2003-02-01

    The promise of fusion as a viable 21st century energy source requires the development of advanced structural (MFE and IFE) and optical (IFE) materials that are capable of withstanding the harsh radiation environment that leads to the degradation of physical and mechanical properties. Materials in fusion environments must be able to handle 14 MeV neutrons produced from Deuterium-Tritium nuclear reactions, as well as the insoluble He and reactive H gases that lead to swelling and embrittlement. Additionally, with the requirement of very high thermal loads makes the development of new advanced materials a formidable challenge. The scope of this study was to determine the feasibility of using atomistic simulations to predict the radiation response of novel materials engineered with potentially self-healing properties to survive in radiation environments over very long time-scales. The class of materials that shows promise is what is called a nanocrystalline material. Nanocrystalline materials are defined as those having very fine grains on the order of several to tens of nanometers in size, and consequently very high grain-boundary to volume ratio. Experimental observations [1] suggests that these grain-boundary networks can act as sinks for defects and hence promote self-repair.

  7. Experimental studies on particle impaction and bounce: effects of substrate design and material

    Microsoft Academic Search

    Mingchih Chang; Seongheon Kim; Constantinos Sioutas

    1999-01-01

    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 conducted using a personal particle sampler (PPS) developed by the University of Southern California. The PPS operates at flow rate of 4 lmin-1

  8. Programming the Material World A Proposition for the Application and Design of Transitive Materials

    Microsoft Academic Search

    Marcelo Coelho

    This paper explores technical and aesthetic possibilities for the convergence of smart materials and computation. It describes Pulp-Based Computing , Sprout I\\/O and Shutters , with particularly emphasis on how craft , collocated input\\/output and material intelligence can provide the framework for extending computation and interactivity into our everyday objects and spaces. By leveraging the dynamic properties of smart materials,

  9. Evaluation of Material Design Limits for TBM Applications

    Microsoft Academic Search

    R. Sunyk; J. Aktaa

    2005-01-01

    The aim of the work presented is, firstly, an evaluation of existing design rules considered for austenitic steels exhibiting hardening cycle by cycle contrary to the reduced activation ferritic-martensitic steels (RAFM), which soften under cyclic loading. Secondly, it is a definition of the range of operation temperatures and loads for the current design of the test blanket module (TBM). Results

  10. 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. ...

  11. Use of UHPC in Bridge Structures: Material Modeling and Design

    E-print Network

    Gunes, Oguz

    Ultra-high-performance concrete (UHPC) is a promising new class of concrete material that is likely to make a significant contribution to addressing the challenges associated with the load capacity, durability, sustainability, ...

  12. Thermoelectric materials evaluation program spring design to minimize load relaxation

    SciTech Connect

    Grimm, F.R.

    1980-03-31

    The recommended spring material for use in thermoelectric modules is either Inconel x or Elgiloy based on their excellent performance and availability. The stress level for generator applications is 75,000 psi. (FS)

  13. Design and Discovery of Highly Efficient Thermoelectric Materials

    NASA Technical Reports Server (NTRS)

    Fleurial, J. P.

    1998-01-01

    Thermoelectric energy conversion efficiency is directly related to the temperature difference over which the device operates, its average temperature of operation and the transport properties of the thermocouple material represented by ZT, the dimensionless figure of merit.

  14. 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.

  15. Thermoelectric materials evaluation program spring design to minimize load relaxation

    Microsoft Academic Search

    1980-01-01

    The recommended spring material for use in thermoelectric modules is either Inconel x or Elgiloy based on their excellent performance and availability. The stress level for generator applications is 75,000 psi. (FS)

  16. Design of novel lithium storage materials with a polyanionic framework

    E-print Network

    Kim, Jae Chul, Ph. D. Massachusetts Institute of Technology

    2014-01-01

    Lithium ion batteries for large-scale applications demand a strict safety standard from a cathode material during operating cycles. Lithium manganese borate (LiMnBO?) that crystallizes into a hexagonal or monoclinic framework ...

  17. Design, synthesis, and characterization of new materials for thermoelectric applications

    Microsoft Academic Search

    Thomas Kent Reynolds

    2003-01-01

    Currently, the best known material for thermoelectric refrigeration at room temperature is and alloy of Bi2Te3 and Sb 2Te3. This material has been the basis for room temperature thermoelectric cooling for over 40 years, but its low cooling efficiency (≈10% of Carnot Efficiency) has limited its adaptation to small-market specialty applications. Since Bi2Te3 and its alloys have been studied so

  18. 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

  19. Catalytic converter design and materials. (A bibliography from the Global Mobility database). Published Search

    SciTech Connect

    Not Available

    1993-12-01

    The bibliography contains citations concerning the various designs, configurations, and materials used in catalytic converters to diminish emissions from automotive, truck, diesel, and off-highway vehicles. Citations examine designs using internal flows and diffuser-monolith flows; the effects of flow maldistribution and steady state heat transfer; and materials, including platinum-palladium, urea-SCR, and copper-zeolite. Light-off and three-way catalysts and those designed for natural gas are emphasized. References also cite air/fuel tests, Taguchi techniques, and European and American standards affecting design and materials. (Contains a minimum of 220 citations and includes a subject term index and title list.)

  20. Catalytic converter design and materials. (Bibliography from the Global Mobility database). Published Search

    SciTech Connect

    NONE

    1997-06-01

    The bibliography contains citations concerning the various designs, configurations, and materials used in catalytic converters to diminish emissions from automotive, truck, diesel, and off-highway vehicles. Citations examine designs using internal flows and diffuser-monolith flows; the effects of flow maldistribution and steady state heat transfer; and materials, including platinum-palladium, urea-SCR, and copper-zeolite. Light-off and three-way catalysts and those designed for natural gas are emphasized. References also cite air/fuel tests, Taguchi techniques, and European and American standards affecting design and materials. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  1. 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.

  2. 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…

  3. Computational materials science aided design of glass ceramics and crystal properties (abstract only)

    Microsoft Academic Search

    Wolfgang Mannstadt

    2008-01-01

    Today's high tech materials have in many cases highly specialized properties and designed functionalities. Materials parameters like high temperature stability, high stiffness and certain optical properties have to be optimized and in many cases an adaptation to given processes is necessary. Many materials are compounds or layered structures. Thus, surface and interface properties need to be considered as well. At

  4. Vision for the University of Connecticut Technology Park Materials Discovery, Product Design & Development

    E-print Network

    Lozano-Robledo, Alvaro

    for the Tech Park which will house the Connecticut Collaboratory for Materials & Manufacturing (C2M2;2 The compelling reasons for the manufacturing and materials emphasis of the inaugural building of the Tech ParkVision for the University of Connecticut Technology Park Materials Discovery, Product Design

  5. 46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Hydraulic or pneumatic power and control-materials...Materials and Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials...flanges, and standard valves) for hydraulic or pneumatic power and control...

  6. Materials design and development of fluoropolymers for use as pellicles in 157-nm photolithography

    Microsoft Academic Search

    Roger H. French; Joseph S. Gordon; David J. Jones; M. F. Lemon; Robert C. Wheland; Xun Zhang; Fredrick C. Zumsteg; Kenneth G. Sharp; Weiming Qiu

    2001-01-01

    The introduction of 157 nm as the next optical lithography wavelength has created a need for new soft (polymeric) or hard (quartz) pellicle materials optimized for this wavelength. Materials design and development of ultra transparent fluoropolymers suitable for 157 nm soft pellicle applications has produced a number of promising candidate materials with absorbances below 0.03\\/micrometer as is necessary to achieve

  7. Materials Design and Development of Fluoropolymers for Use as Pellicles in 157nm Photolithography

    Microsoft Academic Search

    Roger H. Frencha; David J. Jonesa; M. F. Lemon; R obert C. Wheland

    The introduction of 157nm as the next optical lithography wavelength has created a need for new soft (polymeric) or hard (quartz) pellicle materials optimized for this wavelength. Materials design and development of ultra transparent fluoropolymers suitable for 157 nm soft pellicle applications has produced a number of promising candidate materials with absorbances below 0.03\\/µm as is necessary to achieve pellicle

  8. 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.

  9. Elementary Students’ Learning of Materials Science Practices Through Instruction Based on Engineering Design Tasks

    Microsoft Academic Search

    Kristen Bethke Wendell; Hee-Sun Lee

    2010-01-01

    Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline\\u000a within the study of matter. This paper examines how third grade students’ materials science performance changes over the course\\u000a of instruction based on an engineering design challenge. We conducted a case study of nine students who participated in engineering\\u000a design-based science instruction with the

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

    SciTech Connect

    Zacharia, T. [Oak Ridge National Lab., TN (United States). Metals and Ceramics

    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.

  11. 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.

  12. Advanced elastomeric seal design and material for automotive crankshaft applications

    SciTech Connect

    Jackowski, R.; Keller, R.; Strubel, D.

    1987-01-01

    The small, lightweight engines of today require elastomeric lip seals to operate at higher shaft speeds and elevated temperatures while retained in aluminum housings and subjected to aggressive cil additives. The use of fluorelastomer in place of silicone material has provided improved seal performance in engine applications. An advanced crankshaft seal, incorporating a half rubber/half metal O.D. and a superior fluoroelastomer material, has been developed to improve seal installation and retention in aluminum housings and extend seal life beyond the present seal technology.

  13. 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…

  14. 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.

  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. Photovoltaic module encapsulation design and materials section, volume 2

    NASA Astrophysics Data System (ADS)

    Cuddihy, E. F.

    1984-06-01

    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.

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

    Microsoft Academic Search

    E. F. Cuddihy

    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

  18. Advanced elastomeric seal design and material for automotive crankshaft applications

    Microsoft Academic Search

    R. Jackowski; R. Keller; D. Strubel

    1987-01-01

    The small, lightweight engines of today require elastomeric lip seals to operate at higher shaft speeds and elevated temperatures while retained in aluminum housings and subjected to aggressive cil additives. The use of fluorelastomer in place of silicone material has provided improved seal performance in engine applications. An advanced crankshaft seal, incorporating a half rubber\\/half metal O.D. and a superior

  19. Performance of pavements designed with low-cost materials

    NASA Astrophysics Data System (ADS)

    Grau, R. W.; Yrjanson, W. A.; Packard, R. G.; Barksdale, R. D.; Potts, C. F.; Ruth, B. E.; Smith, L. L.; Huddleston, I. J.; Vinson, T. S.; Hicks, R. G.

    1980-04-01

    The following areas are discussed. Utilization of marginal aggregate materials for secondary road surface layers; econocrete pavements; current practices; construction and performance of sand-asphalt bases and performance of sand-asphalt and limerock pavements in Florida. Cement stabilization of degrading aggregates use of crushed stone screenings in highway construction (abridgement); and sulfur-asphalt pavement technology are also reviewed.

  20. Designing materials for plasmonic systems: the alkali-noble intermetallics.

    PubMed

    Blaber, M G; Arnold, M D; Ford, M J

    2010-03-10

    We use electronic structure calculations based upon density functional theory to search for ideal plasmonic materials among the alkali-noble intermetallics. Importantly, we use density functional perturbation theory to calculate the electron-phonon interaction and from there use a first order solution to the Boltzmann equation to estimate the phenomenological damping frequency in the Drude dielectric function. We discuss the necessary electronic features of a plasmonic material and investigate the optical properties of the alkali-noble intermetallics in terms of some generic plasmonic system quality factors. We conclude that at low negative permittivities, KAu, with a damping frequency of 0.0224 eV and a high optical gap to bare plasma frequency ratio, outperforms gold and to some extent silver as a plasmonic material. Unfortunately, a low plasma frequency (1.54 eV) reduces its utility in modern plasmonics applications. We also discuss, briefly, the effect of local fields on the optical properties of these materials. PMID:21389416

  1. 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.

  2. A Practical Approach To Preform Design For Different Materials

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

    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.

  3. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1990-06-01

    The objective is to return a 1 Kg Martian soil sample from the surface of Mars to a mother-ship 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.

  5. 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.

  6. 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.

  7. The influence of material and design on total knee replacement wear.

    PubMed

    Essner, Aaron; Herrera, Lizeth; Hughes, Phillip; Kester, Mark

    2011-03-01

    It is difficult for surgeons to make the decision on which design or material to use given the different options available. Marketing claims and direct-to-consumer advertising certainly complicate this further. One company may claim a higher percentage of wear reduction with their bearing surfaces compared with those of another manufacturer. If the percentage of wear reduction is lower, it is unclear as to whether this creates a more effective technology for reducing wear in the clinical situation. The relative contribution and relationship of design and materials to wear performance must be considered before making that important judgment. To examine the overall influence of implant design on wear reduction, a knee simulator study was undertaken. This simulator study compared the Oxinium Genesis II system with the Triathlon Conventional and Triathlon X3 knee systems under physiologic stair-climb loading and motion profiles. This allows a similar comparison of material effect within one design but also a global comparison across designs. Test results show the Triathlon Conventional and Triathlon X3 knee systems have superior wear resistance compared with that of the Genesis II Oxinium system under stair-climbing simulation. This finding indicates that implant design plays a more significant role in knee wear reduction than material. Although material technology may improve a given knee system's ability to wear, design geometry has a first-order effect and should be addressed before materials. This study represents an effort to differentiate design effect from two different approaches to material enhancement. The results of this study support the predominance of design in knee replacement wear performance. Ultimately, only clinical evidence such as published studies or outcomes reported in the available joint registries will establish whether any material or design can achieve a 30-year outcome. PMID:21618933

  8. Self-expanding nitinol stents: material and design considerations

    Microsoft Academic Search

    Dieter Stoeckel; Alan Pelton; Tom Duerig

    2004-01-01

    Nitinol (nickel–titanium) alloys exhibit a combination of properties which make these alloys particularly suited for self-expanding stents. Some of these properties cannot be found in engineering materials used for stents presently. This article explains the fundamental mechanism of shape memory and superelasticity, and how they relate to the characteristic performance of self-expanding stents. Nitinol stents are manufactured to a size

  9. Rational design of organic electro-optic materials

    Microsoft Academic Search

    L R Dalton

    2003-01-01

    Quantum mechanical calculations are used to optimize the molecular first hyperpolarizability of organic chromophores and statistical mechanical calculations are used to optimize the translation of molecular hyperpolarizability to macroscopic electro-optic activity (to values of greater than 100 pm V?1 at telecommunications wavelengths). Macroscopic material architectures are implemented exploiting new concepts in nanoscale architectural engineering. Multi-chromophore-containing dendrimers and dendronized polymers not

  10. TOPICAL REVIEW: Rational design of organic electro-optic materials

    Microsoft Academic Search

    L. R. Dalton

    2003-01-01

    Quantum mechanical calculations are used to optimize the molecular first hyperpolarizability of organic chromophores and statistical mechanical calculations are used to optimize the translation of molecular hyperpolarizability to macroscopic electro-optic activity (to values of greater than 100 pm V-1 at telecommunications wavelengths). Macroscopic material architectures are implemented exploiting new concepts in nanoscale architectural engineering. Multi-chromophore-containing dendrimers and dendronized polymers not

  11. Performance of pavements designed with low-cost materials

    Microsoft Academic Search

    R. W. Grau; W. A. Yrjanson; R. G. Packard; R. D. Barksdale; C. F. Potts; B. E. Ruth; L. L. Smith; I. J. Huddleston; T. S. Vinson; R. G. Hicks

    1980-01-01

    The following areas are discussed. Utilization of marginal aggregate materials for secondary road surface layers; econocrete pavements; current practices; construction and performance of sand-asphalt bases and performance of sand-asphalt and limerock pavements in Florida. Cement stabilization of degrading aggregates use of crushed stone screenings in highway construction (abridgement); and sulfur-asphalt pavement technology are also reviewed. Bibtex entry for this abstract

  12. Structural materials for ITER in-vessel component design

    Microsoft Academic Search

    G. Kalinin; W. Gauster; R. Matera; A.-A. F. Tavassoli; A. Rowcliffe; S. Fabritsiev; H. Kawamura

    1996-01-01

    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\\/m2 in the basic performance phase (BPP)) within a temperature range from 20 to 300°C. Austenitic SS 316LN-ITER Grade was defined as

  13. (Design and licensing of radioactive material shipping containers)

    SciTech Connect

    Shappert, L.B.

    1987-06-29

    The Bundesanstalt fuer Materialpruefung (BAM) in West Berlin sponsored a seminar and workshop dealing with ductile cast iron (DCI) as a material of construction for spent fuel shipping casks. Tuesday, June 9, was given to US participants to discuss the United States licensing procedures for spent fuel shipping containers with emphasis on ductile cast iron (DCI) as a material of construction and the possible role of DCI containers in the DOE cask program. This author gave the first invited paper which provided a broad overview of the US regulations and how they are generally applied by the NRC, particularly as regards new materials of construction. The workshop was held on Wednesday, June 10, and covered, among other things, the development of International Atomic Energy Agency (IAEA) regulations, following by information on testing of DCI, non-destructive testing of DCI and quality assurance (QA) measures applied to spent fuel shipping and storage containers. Of greater interest were the technical topics in which the application of fracture mechanics on DCI, properties of thick-walled DCI pieces, dynamic fracture toughness tests, and manufacturing methods that are applied to DCI containers were discussed. In addition, a discussion was held on the experiences several countries have had with containers fabricated from DCI, as well as a discussion of the research on DCI that is being carried out at Sandia National Laboratories (SNL) for DOE.

  14. Design and processing of porous materials for electronic applications.

    PubMed

    Willoughby, A F W

    2006-01-15

    The use of porosity, either unintentionally or intentionally, in the fabrication of materials for electronic and optoelectronic applications is introduced. Unintentional uses include the fabrication of ceramic magnets, where high electrical resistivities are required to reduce eddy currents at high frequency, and the powder technology, often used, inevitably results in porosity. The generation of light from porous silicon created a huge impact in the early 1990s, followed by extensive work on the mechanism responsible, and has now been followed by a more balanced evaluation of its potential. Porous ferroelectrics have shown significant advantages over dense materials for positive temperature coefficient of resistance applications, and for sensors such as hydrophones, and these will be discussed. Low dielectric constant materials are required for the next generation of silicon integrated circuits, where a reduction compared with silicon dioxide is required, and here porosity is a convenient strategy. Finally, the use of deliberately engineered porous nanostructures, with dimensions in the range of the wavelength of light, are discussed for applications in optical processing. PMID:18272459

  15. 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.

  16. 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

  17. Design and fabrication of far ultraviolet filters based on ?-multilayer technology in high-k materials

    PubMed Central

    Wang, Xiao-Dong; Chen, Bo; Wang, Hai-Feng; He, Fei; Zheng, Xin; He, Ling-Ping; Chen, Bin; Liu, Shi-Jie; Cui, Zhong-Xu; Yang, Xiao-Hu; Li, Yun-Peng

    2015-01-01

    Application of ?-multilayer technology is extended to high extinction coefficient materials, which is introduced into metal-dielectric filter design. Metal materials often have high extinction coefficients in far ultraviolet (FUV) region, so optical thickness of metal materials should be smaller than that of the dielectric material. A broadband FUV filter of 9-layer non-periodic Al/MgF2 multilayer was successfully designed and fabricated and it shows high reflectance in 140–180?nm, suppressed reflectance in 120–137?nm and 181–220?nm. PMID:25687255

  18. Opportunities and challenges for first-principles materials design and applications to Li battery materials

    E-print Network

    Ceder, Gerbrand

    The idea of first-principles methods is to determine the properties of materials by solving the basic equations of quantum mechanics and statistical mechanics. With such an approach, one can, in principle, predict the ...

  19. 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.

  20. Optical design study in the 1-5?m spectral band with gradient-index materials

    NASA Astrophysics Data System (ADS)

    McCarthy, Peter; Berman, Rebecca; Williams, Daniel J. L.; Yee, Anthony; Moore, Duncan T.

    2014-12-01

    A design study is conducted in the 1-5?m wavelength band for an F/3, 15 degree full field of view, 38mm focal length imaging system. A survey of preferred materials shows the chromatic properties of homogeneous materials in different regions of this spectrum. A survey of GRIN materials, including zinc selenide zinc sulfide GRIN, aluminum oxynitride GRIN, and chalcogenide GRIN, expands the available chromatic properties in this spectral band. Baseline homogeneous triplet designs are explored and compared to previous studies in the literature. The inclusion of a GRIN material in the three element design improves the chromatic correction and results in a system that is nearly diffraction-limited. The three element design is reduced to two elements, where both elements are GRIN, while maintaining comparable performance to the homogeneous triplet.

  1. Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to

    E-print Network

    Rogers, John A.

    Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses complementary metal-oxide-semi- conductor (CMOS) integrated circuits approaching that of conven- tional devices of single crystalline silicon nanomaterials for the semiconductor pro- vides performance in stretchable

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    (a) The manufacturer shall not change the design, material, manufacturing process, or construction of a non-standard component unless it has been previously approved by the Commandant, in accordance with paragraph (b) of this...

  3. Design of electronics for a high-resolution, multi-material, and modular 3D printer

    E-print Network

    Kwan, Joyce G

    2013-01-01

    Electronics for a high-resolution, multi-material, and modular 3D printer were designed and implemented. The driver for a piezoelectric inkjet print head can fire its nozzles with one of three droplet sizes ranging from 6 ...

  4. Development of Digital Materials Database for Design and Construction of New Power Plants

    SciTech Connect

    Ren, Weiju [ORNL

    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.

  5. Design of phononic materials\\/structures for surface wave devices using topology optimization

    Microsoft Academic Search

    Cory J. Rupp; Anton Evgrafov; Kurt Maute; Martin L. Dunn

    2007-01-01

    We develop a topology optimization approach to design two- and three-dimensional phononic (elastic) materials, focusing primarily\\u000a on surface wave filters and waveguides. These utilize propagation modes that transmit elastic waves where the energy is contained\\u000a near a free surface of a material. The design of surface wave devices is particularly attractive given recent advances in\\u000a nano- and micromanufacturing processes, such

  6. 78 FR 939 - Notice of Public Meeting: Designation of an Ocean Dredged Material Disposal Sites (ODMDS) in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-07

    ...of Public Meeting: Designation of an Ocean Dredged Material Disposal Sites (ODMDS) in Eastern Long Island Sound; Connecticut...Potential Designation of One or More Ocean Dredged Material Disposal Sites (ODMDS) to Serve the Eastern Long Island Sound...

  7. Establishment of an advanced composite materials design capability - A case for cooperation?

    NASA Astrophysics Data System (ADS)

    Hall, Stephen R.; John, Leonard K.

    1986-09-01

    The development of a Canadian national data bank for the characterization of basic advanced composite materials data is proposed. The materials characterization program is aimed at defining the physical properties of a material so that an engineer can produce cost-effective hardware that complies with specified structural integrity requirements. The costs and benefits of a national data bank for characterization of materials are discussed. Consideration is given to selecting materials for the data bank; defining material processing and quality control techniques; initial acceptance and storage requirements; manufacturing procedures and inspection; the manufacture and design of test specimens; the testing of specimens; and methods for obtaining design allowables. The management of the data bank, it structure, and the membership criteria are examined.

  8. 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…

  9. Designer's Guide to Radiation Effects on Materials for Use on Jupiter Fly-Bys and Orbiters

    Microsoft Academic Search

    Frank L. Bouquet; William E. Price; Donald M. Newell

    1979-01-01

    This paper summarizes the state-of-the-art of the complex field of radiation effects on spacecraft materials. It is intended as a guide for designers of systems exposed to damaging electrons and protons. The emphasis is on the relative damage levels for the more common materials that may be used. Information on the preliminary flux and fluence levels of the yet to

  10. 46 CFR 160.176-6 - 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. ? 160.176-6 ? Section 160.176-6 ? Shipping ? COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ? EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL ?...

  11. A new era in cable designs and materials to resolve environmental issues

    Microsoft Academic Search

    Roger E. Barras; Kenneth E. Bow; Joseph H. Snow; D. A. Volz

    1997-01-01

    In recent years, environmental issues have had a profound influence on power cable designs and materials used in cable construction. This paper addresses the issues concerned with the effects of cables on the environment, as well as the effects of environmental conditions on cable performance and reliability. Effects on the environment include release of toxic materials and contamination of ground

  12. A new era in cable designs and materials to resolve environmental issues

    Microsoft Academic Search

    Roger E. Barras; J. H. Snow; K. E. Bow; Donald A. Voltz

    1996-01-01

    Environmental issues have had a profound influence on cable designs and materials used in cable construction. This paper addresses the issues concerned with the effects of cable on the environment, as well as the effects of environmental conditions on cable performance and reliability. Effects on the environment include release of toxic materials and contamination of ground water. Environmental effects on

  13. Design and evaluation of online courses containing media?enhanced learning materials

    Microsoft Academic Search

    Paul Lam; Carmel McNaught

    2006-01-01

    With the current state of web technology, multimedia materials are readily accessible by students. This paper reports on the design and evaluation of three online courses from a university in Hong Kong which incorporate media?enhanced learning materials. These cases are at different positions with respect to the types of knowledge and levels of cognitive reasoning outlined in the revised Bloom’s

  14. First wall and blanket module safety enhancement by material selection and design decision

    Microsoft Academic Search

    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

  15. A Co-designed Hardware\\/Software Architecture for Augmented Materials

    Microsoft Academic Search

    Simon Dobson; Kieran Delaney; Kafil Mahmood Razeeb; Sergey Tsvetkov

    2005-01-01

    Recent advances in materials, sensing, power harvesting, context- awareness and miniaturisation have opened-up the possibility of con- structing materials that directly include considerable computing power. We present an architecture for the hardware\\/software co-design of such \\

  16. Design ant1Implementation of an Automatic Material Handling System Using Petri Nets

    E-print Network

    Kim, Jongwon

    , simulation, design and implementation of an automatic material handling system in a batch production batch production line. The comparison of the performance capability expected by the Petri net simulation to shorten the overall delays of batch production. The automatic material handling system is classified

  17. Journal of Computer-Aided Materials Design, 8: 127149, 2001. KLUWER/ESCOM

    E-print Network

    Goddard III, William A.

    This paper is concerned with the development of a multiscale modeling approach for advanced materialsJournal of Computer-Aided Materials Design, 8: 127­149, 2001. KLUWER/ESCOM © 2002 Kluwer Academic IIIc and MICHAEL ORTIZd aDepartment of Mechanical and Aerospace Engineering, Rutgers University

  18. Carrier pocket engineering applied to ``strained'' Si/Ge superlattices to design useful thermoelectric materials

    E-print Network

    Cronin, Steve

    /Ge superlattices to obtain a large thermoelectric figure of merit ZT. In this system, the effect of the lattice to provide a promising strategy for designing materials with a large thermoelectric figure of merit ZT thermoelectric materials T. Koga,a) X. Sun, S. B. Cronin, and M. S. Dresselhausb) Department of Physics

  19. Materials issues in the design of the ITER first wall, blanket, and divertor

    SciTech Connect

    Mattas, R.F.; Smith, D.L. (Argonne National Lab., IL (United States)); Wu, C.H. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany). NET Team); Koroda, T. (Japan Atomic Energy Research Inst., Ibaraki-ken (Japan)); Shatalov, G. (Kurchatov Inst. of Atomic Energy, Moscow (USSR))

    1992-01-01

    During the ITER conceptual design study, a property data base was assembled, the key issues were identified, and a comprehensive R D plan was formulated to resolve these issues. The desired properties of candidate ITER divertor, first wall, and blanket materials are briefly reviewed, and the major materials issues are presented. Estimates of the influence of materials properties on the performance limits of the first wall, blanket, and divertor are presented.

  20. Materials issues in the design of the ITER first wall, blanket, and divertor

    SciTech Connect

    Mattas, R.F.; Smith, D.L. [Argonne National Lab., IL (United States); Wu, C.H. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany). NET Team; Koroda, T. [Japan Atomic Energy Research Inst., Ibaraki-ken (Japan); Shatalov, G. [Kurchatov Inst. of Atomic Energy, Moscow (USSR)

    1992-01-01

    During the ITER conceptual design study, a property data base was assembled, the key issues were identified, and a comprehensive R&D plan was formulated to resolve these issues. The desired properties of candidate ITER divertor, first wall, and blanket materials are briefly reviewed, and the major materials issues are presented. Estimates of the influence of materials properties on the performance limits of the first wall, blanket, and divertor are presented.

  1. Material Characterization and Design Recommendations for Mechanically Stabilized Earth Retaining Walls 

    E-print Network

    Dantal, Vishal

    2013-12-04

    Failure Modes AASHTO (2002) .................... 5 Table 2. Material Parameters Used by TxDOT Yoon (2011). ........................................... 8 Table 3. Unit Weights for Select Backfill TxDOT (2012... (Adams et al. 2011). 2 This research encompasses different aspects of MSE wall components required in selection of materials and assumption of design parameters. In the following section- 2, it includes a literature review on materials used by Tx...

  2. Design and synthesis of inorganic/organic hybrid electrochemical materials

    NASA Astrophysics Data System (ADS)

    Harreld, John H.

    An ambient pressure method for drying sol-gel materials is developed to synthesize high porosity (80--90%), high surface area vanadium oxide and silica aerogel materials (150--300 and 1000 m2/g for vanadium pentoxide and silica, respectively). The synthesis approach uses liquid exchange to replace the pore fluid with a low surface tension, nonpolar solvent which reduces the capillary pressures developed during drying. The Good-Girifalco interaction parameter is used to calculate pore stresses resulting from drying silica gels from various liquids. Vanadium oxide/polypyrrole hybrid aerogels are prepared using three strategies. These approaches focus on either sequential or consecutive polymerization of the inorganic and organic networks. Microcomposite aerogels are synthesized by encapsulating a dispersion of preformed polypyrrole in a vanadium pentoxide gel. In the second approach, pyrrole is polymerized and doped within the pore volume of preformed vanadium pentoxide gel. When the inorganic and organic precursors are polymerized simultaneously, the resulting gels exhibited a nanometer scaled microstructure with homogeneous distributions of either phases. Through this route, a suitable microstructure and composition for a lithium secondary battery cathode is obtained. Lithiated aerogels of hydrated nickel, cobalt, and mixed nickel-cobalt oxides are synthesized from lithium hydroxide and transition metal acetate precursors. The XRD analyses indicate that the nickel containing gels exhibit a lithium deficiency (less than 1 Li/transition metal. By increasing the concentration of the lithium precursor the lithium content in nickel oxides is increased, and additional base solution is no longer required to catalyze gelation. A non-hydrolytic sol-gel approach is utilized to create tin oxide and tin-aluminum binary oxide aerogels with high porosity (90%) and high surface area (300 m2/g). XRD data from single phase tin oxide aerogel indicates the growth of SnO2 crystallites between 150--400°C in air, accompanied by a reduction in surface area (30 m2/g). Heated tin oxide aerogel exhibits comparable reversible specific capacity (390 mAh/g) as that of commercial SnO2 (420 mAh/g). Amorphous tin oxide aerogel is stabilized to higher temperatures when aluminum oxide is incorporated into the structure. The tin oxide phase remains electrochemically active towards lithium insertion and exhibits excellent reversibility during cycling.

  3. 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.

  4. TOPICAL REVIEW: Rational design of organic electro-optic materials

    NASA Astrophysics Data System (ADS)

    Dalton, L. R.

    2003-05-01

    Quantum mechanical calculations are used to optimize the molecular first hyperpolarizability of organic chromophores and statistical mechanical calculations are used to optimize the translation of molecular hyperpolarizability to macroscopic electro-optic activity (to values of greater than 100 pm V-1 at telecommunications wavelengths). Macroscopic material architectures are implemented exploiting new concepts in nanoscale architectural engineering. Multi-chromophore-containing dendrimers and dendronized polymers not only permit optimization of electro-optic activity but also of auxiliary properties including optical loss (both absorption and scattering), thermal and photochemical stability and processability. New reactive ion etching and photolithographic techniques permit the fabrication of three-dimensional optical circuitry and the integration of that circuitry with semiconductor very-large-scale integration electronics and silica fibre optics. Electro-optic devices have been fabricated exploiting stripline, cascaded prism and microresonator device structures. Sub-1 V drive voltages and operational bandwidths of greater than 100 GHz have been demonstrated. Both single-and double-ring microresonators have been fabricated for applications such as active wavelength division multiplexing. Free spectral range values of 1 THz and per channel modulation bandwidths of 15 GHz have been realized permitting single-chip data rates of 500 Gb s-1. Other demonstrated devices include phased array radar, optical gyroscopes, acoustic spectrum analysers, ultrafast analog/digital converters and ultrahigh bandwidth signal generators.

  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. Path-following methods for shape optimal design of periodic microstructural materials

    Microsoft Academic Search

    Ronald H. W. Hoppe; Svetozara I. Petrova

    2009-01-01

    We are concerned with optimal shape design of composite materials with periodic microstructures. The homogenization approach is applied to obtain a computationally feasible macromodel. The microstructural geometrical details of the microcells (such as lengths and widths of the different layers forming the cell walls) are considered as design parameters. They have a tremendous impact on the macroscopic behaviour of the

  7. How to solve materials and design problems in solar heating and cooling

    Microsoft Academic Search

    D. S. Ward; H. S. Oberoi; S. D. Weinstein

    1982-01-01

    This book discusses the solving of materials and design problems in solar heating and cooling. Based on two studies - one for ASHRAE and the US Dept. of Energy, and one for Argonne National Laboratory, the book consolidates a large body of information on difficulties encountered in the design, installation, operation, testing, and maintenance of solar heating and cooling systems.

  8. Design and construction of model steam generators for corrosion testing of alternative materials. [PWR

    Microsoft Academic Search

    J. J. Krupowicz; J. E. Casteel; B. W. Kinyon

    1981-01-01

    This topical report describes the design and construction of two model steam generators which were built to test the corrosion resistance of contemporary and alternative steam generator materials under secondary water conditions. The models include several new design features rendering them more representative of actual steam generators. Extensive thermal and hydraulic analyses of the models are also presented and discussed.

  9. 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…

  10. Optimizing Tank Car Safety Design to Reduce Hazardous Materials Transportation Risk

    E-print Network

    Barkan, Christopher P.L.

    1 Optimizing Tank Car Safety Design to Reduce Hazardous Materials Transportation Risk M. Rapik Saat & Safety Population Density Improve tank car safety design Improve track condition Operational changes Total Cost & Safety Tank Car Derailment Release Quantity Hazard Exposure Area Population Density

  11. Optimal Design of Microstructures of Elastic Wave Band Gap Truss Materials

    Microsoft Academic Search

    Nolan Fox

    This paper deals with the modeling of band gaps in truss-like materials using a spring-mass model. It seeks to be a thorough examination of the properties, the classification, and the design of phononic band gaps. Consequently, this paper provides a rather thorough background explanation that should provide a good working knowledge on the design and properties of phononic band gaps.

  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. Design and material selection guidelines and strategies for transparent armor systems

    E-print Network

    Grujicic, Mica

    Design and material selection guidelines and strategies for transparent armor systems M. Grujicic Available online 2 August 2011 Keywords: Transparent-armor Ballistics Design a b s t r a c t As evidenced by the recent experience of the US Armed Forces involved in the missions in Iraq and Afghanistan, armoring

  14. Design assessment of ITER port plug plasma facing material options

    NASA Astrophysics Data System (ADS)

    Lisgo, S. W.; Börner, P.; Kukushkin, A.; Pitts, R. A.; Polevoi, A.; Reiter, D.

    2011-08-01

    The objective of this computational engineering design study is to assess whether the ITER confined plasma will be adversely affected if the diagnostic port plug and tritium breeding module plasma-facing surfaces are left as bare stainless steel or armoured with W, rather than with Be as on the rest of the main chamber first wall. The OSM-EIRENE-DIVIMP code package is employed to determine the 2D steady-state impurity distribution, after benchmarking the OSM plasma calculations against reference SOLPS simulations. For far-SOL transport, the computational domain is extended to explicitly include plasma contact with the wall. To sample a large area of the foreseen ITER parameter space, a range of boundary plasmas are assigned via OSM based on observed experimental trends, including radial decay lengths, parallel flows, and pedestal profiles. Taking core impurity limits from ASTRA simulations, the results indicate that Be cladding of the port plugs under consideration is not required, with the proviso that neutral particle injection directly in front of the ports is avoided.

  15. On the design of structural components using materials with time-dependent properties

    NASA Technical Reports Server (NTRS)

    Rodriguez, Pedro I.

    1993-01-01

    The application of the elastic-viscoelastic correspondence principle is presented as a design tool for structural design engineers for composite material applications. The classical problem of cantilever beams is used as the illustration problem. Both closed-form and approximate numerical solutions are presented for several different problems. The application of the collocation method is presented as a viable and simple design tool to determine the time-dependent behavior and response of viscoelastic composite beams under load.

  16. 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.

  17. 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 applications in biomimetics, optics/photonics, functional surfaces, and photoswitchable supramolecules. PMID:23805801

  18. Negative index of refraction in optical metamaterials

    Microsoft Academic Search

    Vladimir M. Shalaev; Wenshan Cai; Uday K. Chettiar; Hsiao-Kuan Yuan; Andrey K. Sarychev; Vladimir P. Drachev; Alexander V. Kildishev

    2005-01-01

    A double-periodic array of pairs of parallel gold nanorods is shown to have a negative refractive index in the optical range. Such behavior results from the plasmon resonance in the pairs of nanorods for both the electric and the magnetic components of light. The refractive index is retrieved from direct phase and amplitude measurements for transmission and reflection, which are

  19. Negative index bulk metamaterial at terahertz frequencies

    E-print Network

    -handed metallic metamaterials," Opt. Commun. 280, 213­216 (2007). 11. W. J. Padilla, A. J. Taylor, C. Highstrete Frequencies," Phys. Rev. Lett. 96, 107,401 (2006). 12. H.-T. Chen, W. J. Padilla, J. M. O. Zide, A. C. Gossard of and ," Soviet Physics Uspekhi 10, 509­514 (1968). 14. D. R. Smith, W. J. Padilla, D. C. Vier, S. C. Nemat

  20. 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.

  1. The effect of new priorities and new materials on residential refrigerator design

    SciTech Connect

    Benson, D.K.; Potter, T.F.

    1992-08-01

    Increasing energy-efficiency requirements, combined with environmental considerations, have resulted in designs for domestic refrigerators that incorporate new thermal insulating materials. The first series of tests of these materials have been sufficiently promising that incorporation of vacuum insulations if likely within the next several years. Initial designs will probably use a combination of vacuum insulations and foam; in future designs, major parts consolidation will be possible using structural and other characteristics of the new panel assemblies. Given optimization of the refrigerator thermal envelope according to life-cycle costs, energy use by refrigerators could be greatly reduced; refrigerators could lose their significance as a major component in residential energy-use. Possible forms in which these new materials will be used are discussed, including alternatives for composite assembly and requirements for reliability and durability.

  2. 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

  3. 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.

  4. Materials and mechanical design analysis of boron carbide reactor safety rods

    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.

  5. Materials and design experience in a slurry-fed electric glass melter

    Microsoft Academic Search

    S. M. Barnes; D. E. Larson

    1981-01-01

    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

  6. Computational design and optimization of a biomimetic self-healing\\/cooling composite material

    Microsoft Academic Search

    Alejandro M. Aragón; Christopher J. Hansen; Willie Wu; Philippe H. Geubelle; Jennifer Lewis; Scott R. White

    2007-01-01

    Inspired by natural examples of microvascular systems in a wide variety of living organisms, we perform the computational design of a new class of polymer-based composite materials with the unique ability to heal and\\/or cool in a completely autonomic fashion, i.e., without any external intervention. The design process combines graph theory to represent and evaluate the microvascular network and Genetic

  7. Comparison of the thermal effects on LWIR optical designs utilizing different infrared optical materials

    NASA Astrophysics Data System (ADS)

    Huddleston, Jeremy; Symmons, Alan; Pini, Ray

    2014-06-01

    The growing demand for lower cost infrared sensors and cameras has focused attention on the need for low cost optics for the long wave and mid-wave infrared region. The thermal properties of chalcogenides provide benefits for optical and optomechanical designers for the athermalization of lens assemblies as compared to Germanium, Zinc Selenide and other more common infrared materials. This investigation reviews typical infrared materials' thermal performance and the effects of temperature on the optical performance of lens systems manufactured from various optical materials.

  8. UCLA CHEMISTRY-MATERIALS SCIENCE MAJOR 2012-2013 CHEMISTRY-MATERIALS SCIENCE MAJOR (B.S.): This major is designed primarily for students who are interested in

    E-print Network

    Levine, Alex J.

    UCLA CHEMISTRY-MATERIALS SCIENCE MAJOR 2012-2013 CHEMISTRY-MATERIALS SCIENCE MAJOR (B.S.): This major is designed primarily for students who are interested in chemistry with an emphasis on material interdisciplinary research involving chemistry, engineering, and applied science. Refer to the UCLA General Catalog

  9. 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.

  10. An experimental study of thermal energy storage with phase change materials by design of experiments

    Microsoft Academic Search

    Belen Zalba; Belen Sanchez-valverde; Jose Marin

    2005-01-01

    Accurate theoretical modelling and simulation of thermal energy storage (TES) by means of phase change materials (PCM) is very complex and its results are not close enough to experimental values. This paper presents the empirical study of a thermal storage unit operating with a commercial PCM called RT25. The study is carried out by means of the statistical procedure, Design

  11. 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)

  12. Optimization design of multi-material micropump using finite element method

    Microsoft Academic Search

    Meiling Zhu; Paul Kirby; Martin Wacklerle; Markus Herz; Martin Richter

    2009-01-01

    This paper presents a micropump fabricated from low cost materials with specific goal of cost reduction. The micropump does not require any valve flap and comprises one plastic pump polyether–ether–ketone (PEEK) body, one metal diaphragm, and three piezoelectric ceramics to form piezoelectrically actuated diaphragm valves. The valve actuation simplifies micropump structural designs and assembly processes to make the pump attractive

  13. 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…

  14. Modeling of Eco Manufacturing Process Design for the Wood Material Coating Stage

    Microsoft Academic Search

    Suthep Butdee; Serge Tichkiewitch

    This paper proposes the model of Eco manufacturing process design for the wood material coating stage. The objective is to improve productivity of the process and ecological aspect for workplace environment. The manufacturing time should be the shortest and also the color spraying emission must be reduced. In this study, different types of coating processes are discussed and compared. The

  15. 46 CFR 160.133-23 - Procedure for approval of design, material, or construction change.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    (a) Each change in design, material, or construction from the plans approved under 46 CFR 159.005-13 and § 160.133-13(h) of this subpart must be approved by the Commandant before being used in any production release...

  16. 46 CFR 160.135-23 - Procedure for approval of design, material, or construction change.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    (a) Each change in design, material, or construction from the plans approved under 46 CFR 159.005-13 and § 160.135-13(h) of this subpart must be approved by the Commandant before being used in any production lifeboat. The manufacturer must submit any such change following the procedures in §...

  17. 46 CFR 160.115-23 - Procedure for approval of design or material change.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    (a) Each change in design, material, or construction from the plans approved under 46 CFR 159.005-13 and § 160.115-13(h) of this subpart must be approved by the Commandant before being used in any production winch. The manufacturer must submit any such change following the procedures in §...

  18. 46 CFR 160.156-23 - Procedure for approval of design, material, or construction change.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    (a) Each change in design, material, or construction from the plans approved under 46 CFR 159.005-13 and § 160.156-13(h) of this subpart must be approved by the Commandant before being used in any production rescue...

  19. Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies

    Microsoft Academic Search

    Z. Yang; P. Dong; S. Liu; S. Babu; G. Olson; T. DebRoy

    2005-01-01

    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

  20. Test blanket modules in ITER: An overview on proposed designs and required DEMO-relevant materials

    E-print Network

    Abdou, Mohamed

    Test blanket modules in ITER: An overview on proposed designs and required DEMO-relevant materials, Russian Federation Abstract Within the framework of the ITER Test Blanket Working Group, the ITER Parties have made several proposals for test blanket modules to be tested in ITER from the first day of H

  1. Improved Kolsky-bar design for mechanical characterization of materials at high strain rates

    Microsoft Academic Search

    Bo Song; Kevin Connelly; John Korellis; Wei-Yang Lu; Bonnie R. Antoun

    2009-01-01

    A Kolsky apparatus with numerous modifications has been designed for mechanical characterization of materials at high strain rates. These modifications include employing a highly precise optical table, pillow blocks with Frelon®-coated linear bearings as bar supports and a laser system for better precision bar alignment, etc. In addition, the striker bars were coated with Teflon® to minimize the friction with

  2. The Implementation of Braided Composite Materials in the Design of a Bend-Twist Coupled Blade

    Microsoft Academic Search

    JAMES LOCKE; CONTREARAS HIDALGO

    2002-01-01

    This report presents results for conceptual wind turbine blade designs that are manufactured using braided composite materials. The SERI-8 wind turbine blade was used to define a geometric model and establish the blade internal volume as well as the primary load-carrying box beam structure. The box beam was modeled in twelve pieces and characterized by its principal dimensions (height, width,

  3. The manufacture of microencapsulated phase change materials suitable for the design of thermally enhanced fabrics

    Microsoft Academic Search

    Nihal Sarier; Emel Onder

    2007-01-01

    Thermal comfort of a fabric is one of the important tasks of the designers that require an engineering approach. In this study, we first aimed to establish a manufacturing technique based on in situ polymerization in order to accomplish the microencapsulation of phase change materials (PCMs) that can ultimately be used in different textile applications, i.e. incorporating such products into

  4. Design and operation of multi-specimen fully reversed fatigue systems for advanced composite materials

    Microsoft Academic Search

    G. Waring; K. E. Hofer Jr.; I. Brown; R. E. Trabocco

    1979-01-01

    Advanced composite materials are finding extensive utilization in aerospace structural applications. The composites appear usually as the skins (surfacing elements) on sandwich components. The paper describes an experimental system designed to investigate the static compressive strengths of graphite\\/epoxy composite sandwich structures with various defects, after exposure to combined moisture-saturation and elevated temperature environment in the presence of fatigue stress cycling

  5. MECH/BIOM-532, Fall 2014 Materials Issues in Mechanical Design Department of Mechanical Engineering

    E-print Network

    MECH/BIOM-532, Fall 2014 ­ Materials Issues in Mechanical Design Department of Mechanical Engineering Colorado State University Course Instructor Dr. Troy B. Holland tbhollan@engr.colostate.edu A110 Engineering (970) 491-1961 Office Hours: Wednesday 12- 2pm, or by appointment Discussion: Mon/Wed, 4-5:15PM

  6. Design and analysis of the lithium target system for the International Fusion Materials Irradiation Facility (IFMIF)

    SciTech Connect

    Hua, T.; Smith, D.; Hassanein, A.; Gomes, I.

    1995-09-01

    Three lithium target design options are being evaluated for the IFMIF. The impact of various requirements on material selection, lifetime, operation and maintenance are discussed. Analysis for the free jet option is presented. Key aspects include jet stability, thermal and nuclear responses.

  7. 1. INTRODUCTION Current design methods focus on crack growth curves which are material properties for given

    E-print Network

    Hively, Lee M.

    1. INTRODUCTION Current design methods focus on crack growth curves which are material properties aluminum, and construction steel under pristine and corroded conditions, and for Mode I and Mode III fatigue, as well as Mode I low-temperature creep and stress corrosion. During the 1930s, A. A. Griffith

  8. Fabrication and device design of bulk and thin film photostrictive materials

    Microsoft Academic Search

    Patcharin Poosanaas-Burke; I. R. Abothu; K. Uchino

    2001-01-01

    Bulk and thin films of lanthanum-modified lead zirconate titanate (PLZT) were fabricated using sol-gel technique. The samples have been evaluated for their electrical, photovoltaic and photostrictive properties to assess their utility in advanced microactuators and sensors. Device based on these materials was designed which will be useful for optical and solar tracking actuators

  9. Carrier pocket engineering to design superior thermoelectric materials using GaAs/AlAs superlattices

    E-print Network

    Cronin, Steve

    Carrier pocket engineering to design superior thermoelectric materials using Ga September 1998 A large enhancement in the thermoelectric figure of merit for the whole superlattice, Z3DT is about 50 times greater than the corresponding ZT for bulk GaAs. © 1998 American Institute of Physics. S

  10. 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…

  11. 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.…

  12. 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.

  13. Shape optimization and material gradient design of the sharp hot structure

    NASA Astrophysics Data System (ADS)

    Ma, Yinji; Yao, Xuefeng; Su, Yunquan

    2014-10-01

    In this paper, the shape and material gradient of the sharp hot structure are designed and optimized to meet the hypersonic flight conditions. First, based on the single-objective optimization for the volume, the aerodynamic loading and the heat flow, respectively, the genetic algorithm (GA) is employed for optimizing the shape of the sharp hot structure. Second, the shape of the sharp hot structure is optimized using multi-objective GA by means of the objectives of the volume, the aerodynamic loading and the heat flow. Finally, the ABAQUS software is used to simulate both the temperature and the stress distribution with different material gradient distributions for the sharp hot structure. The optimal distributions of gradient materials for the sharp hot structure are proposed. The results will provide an important guidance for the design of the sharp hot structure.

  14. 76 FR 26720 - Notice of Intent: Designation of an Expanded Ocean Dredged Material Disposal Site (ODMDS) off...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-09

    ...Intent: Designation of an Expanded Ocean Dredged Material Disposal Site (ODMDS) off Fort Lauderdale, FL AGENCY: U.S. Environmental...ODMDS, approximately 4 square nautical miles in size, for the disposal of dredged material from the potential construction...

  15. 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.

  16. Functionalized graphene and other two-dimensional materials for photovoltaic devices: device design and processing.

    PubMed

    Liu, Zhike; Lau, Shu Ping; Yan, Feng

    2015-08-01

    Graphene is the thinnest two-dimensional (2D) carbon material and has many advantages including high carrier mobilities and conductivity, high optical transparency, excellent mechanical flexibility and chemical stability, which make graphene an ideal material for various optoelectronic devices. The major applications of graphene in photovoltaic devices are for transparent electrodes and charge transport layers. Several other 2D materials have also shown advantages in charge transport and light absorption over traditional semiconductor materials used in photovoltaic devices. Great achievements in the applications of 2D materials in photovoltaic devices have been reported, yet numerous challenges still remain. For practical applications, the device performance should be further improved by optimizing the 2D material synthesis, film transfer, surface functionalization and chemical/physical doping processes. In this review, we will focus on the recent advances in the applications of graphene and other 2D materials in various photovoltaic devices, including organic solar cells, Schottky junction solar cells, dye-sensitized solar cells, quantum dot-sensitized solar cells, other inorganic solar cells, and perovskite solar cells, in terms of the functionalization techniques of the materials, the device design and the device performance. Finally, conclusions and an outlook for the future development of this field will be addressed. PMID:26024242

  17. Design rules for phase-change materials in data storage applications.

    PubMed

    Lencer, Dominic; Salinga, Martin; Wuttig, Matthias

    2011-05-10

    Phase-change materials can rapidly and reversibly be switched between an amorphous and a crystalline phase. Since both phases are characterized by very different optical and electrical properties, these materials can be employed for rewritable optical and electrical data storage. Hence, there are considerable efforts to identify suitable materials, and to optimize them with respect to specific applications. Design rules that can explain why the materials identified so far enable phase-change based devices would hence be very beneficial. This article describes materials that have been successfully employed and dicusses common features regarding both typical structures and bonding mechanisms. It is shown that typical structural motifs and electronic properties can be found in the crystalline state that are indicative for resonant bonding, from which the employed contrast originates. The occurence of resonance is linked to the composition, thus providing a design rule for phase-change materials. This understanding helps to unravel characteristic properties such as electrical and thermal conductivity which are discussed in the subsequent section. Then, turning to the transition kinetics between the phases, the current understanding and modeling of the processes of amorphization and crystallization are discussed. Finally, present approaches for improved high-capacity optical discs and fast non-volatile electrical memories, that hold the potential to succeed present-day's Flash memory, are presented. PMID:21469218

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. The role of vacancies and local distortions in the design of new phase-change materials.

    PubMed

    Wuttig, Matthias; Lüsebrink, Daniel; Wamwangi, Daniel; We?nic, Wojciech; Gillessen, Michael; Dronskowski, Richard

    2007-02-01

    Phase-change materials are of tremendous technological importance ranging from optical data storage to electronic memories. Despite this interest, many fundamental properties of phase-change materials, such as the role of vacancies, remain poorly understood. 'GeSbTe'-based phase-change materials contain vacancy concentrations around 10% in their metastable crystalline structure. By using density-functional theory, the origin of these vacancies has been clarified and we show that the most stable crystalline phases with rocksalt-like structures are characterized by large vacancy concentrations and local distortions. The ease by which vacancies are formed is explained by the need to annihilate energetically unfavourable antibonding Ge-Te and Sb-Te interactions in the highest occupied bands. Understanding how the interplay between vacancies and local distortions lowers the total energy helps to design novel phase-change materials as evidenced by new experimental data. PMID:17173032

  4. Negative Dielectric Constant Material Based on Ion Conducting Materials

    NASA Technical Reports Server (NTRS)

    Gordon, Keith L. (Inventor); Kang, Jin Ho (Inventor); Park, Cheol (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

    2014-01-01

    Metamaterials or artificial negative index materials (NIMs) have generated great attention due to their unique and exotic electromagnetic properties. One exemplary negative dielectric constant material, which is an essential key for creating the NIMs, was developed by doping ions into a polymer, a protonated poly(benzimidazole) (PBI). The doped PBI showed a negative dielectric constant at megahertz (MHz) frequencies due to its reduced plasma frequency and an induction effect. The magnitude of the negative dielectric constant and the resonance frequency were tunable by doping concentration. The highly doped PBI showed larger absolute magnitude of negative dielectric constant at just above its resonance frequency than the less doped PBI.

  5. 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.

  6. Design Rules for Ce-activated scintillating radiation detection materials: Compromises between Luminosity and stopping power

    SciTech Connect

    Webb-Robertson, Bobbie-Jo M.; Ferris, Kim F.; Jones, Dumont M.

    2008-06-01

    In recent years, the scintillation properties of many specific cerium-doped scintillators (such as LSO and BaBr3) have been extensively studied. This paper presents new development methods for property-screening design rules ,using structure-property relationships for two fundamental target detector properties--luminosity and stopping power. The first and most evident goal in developing screening models of luminosity and stopping power is to obtain new candidate cerium scintillating materials. However, a second and more strategic goal is to extract design rules, which define the structural limitations on materials consistent with desirable detector properties. The design rules are based on our capability to predict the luminescence and stopping power of a material from a set of structural descriptors. These models are generated using statistical multiple linear regression techniques over a large set of 24 descriptors. We find that within a set of ten cerium-doped scintillator materials that we can quantitatively predict luminosity and stopping power with a correlation coefficient of ~0.99 based on 6 of the 24 descriptors. Furthermore, we show that in this circumstance the luminosity and stopping power are nominally related and only share one common descriptor in the developed models. In particular luminosity depends largely on matrix valence electron properties and their coupling to activator sites—properties that do not require high atomic masses per se, a requirement for high stopping power.

  7. Optimal experimental designs for the estimation of thermal properties of composite materials

    NASA Technical Reports Server (NTRS)

    Scott, Elaine P.; Moncman, Deborah A.

    1994-01-01

    Reliable estimation of thermal properties is extremely important in the utilization of new advanced materials, such as composite materials. The accuracy of these estimates can be increased if the experiments are designed carefully. The objectives of this study are to design optimal experiments to be used in the prediction of these thermal properties and to then utilize these designs in the development of an estimation procedure to determine the effective thermal properties (thermal conductivity and volumetric heat capacity). The experiments were optimized by choosing experimental parameters that maximize the temperature derivatives with respect to all of the unknown thermal properties. This procedure has the effect of minimizing the confidence intervals of the resulting thermal property estimates. Both one-dimensional and two-dimensional experimental designs were optimized. A heat flux boundary condition is required in both analyses for the simultaneous estimation of the thermal properties. For the one-dimensional experiment, the parameters optimized were the heating time of the applied heat flux, the temperature sensor location, and the experimental time. In addition to these parameters, the optimal location of the heat flux was also determined for the two-dimensional experiments. Utilizing the optimal one-dimensional experiment, the effective thermal conductivity perpendicular to the fibers and the effective volumetric heat capacity were then estimated for an IM7-Bismaleimide composite material. The estimation procedure used is based on the minimization of a least squares function which incorporates both calculated and measured temperatures and allows for the parameters to be estimated simultaneously.

  8. THE IMPACT OF MATERIAL AND DESIGN CRITERIA ON THE ASSESSMENT OF NEGLIGIBLE CREEP

    SciTech Connect

    Sham, Sam [ORNL] [ORNL; Jetter, Robert I [Consultant] [Consultant; Swindeman, Robert W [Consultant] [Consultant

    2009-01-01

    Two of the proposed High Temperature Gas Reactors (HTGRs) under consideration for a demonstration plant have the design object of avoiding creep effects during normal operation. The goal of negligible creep could have different interpretations depending upon what failure modes are considered and associated criteria for avoiding the effects of creep. This paper addresses the criteria for negligible creep in Subsection NH of Section III of the ASME B&PV Code, other international design codes and some currently suggested criteria modifications and their impact on permissible operating temperatures for various reactor pressure vessel materials. There are a number of other considerations for the selection of vessel material besides avoiding creep effects. Of particular interest for this review are (1) the material s allowable stress level and impact on wall thickness (the goal being to minimize required wall thickness) and (2) ASME Code approval (inclusion as a permitted material in the relevant Section and Subsection of interest) to expedite regulatory review and approval. The application of negligible creep criteria to two of the candidate materials, SA533 and Mod 9Cr-1Mo, and to a potential alternate, normalized and tempered 2 Cr-1Mo, are illustrated and the relative advantages and disadvantages are discussed.

  9. Breaking charge conjugation symmetry for novel ?-conjugated donor and acceptor materials design

    NASA Astrophysics Data System (ADS)

    Shin, Yongwoo; Lin, Xi

    2015-03-01

    Seeking for novel ?-conjugated electron-donating materials with targeted optical bandgaps and novel electron-accepting materials with compatible orbital alignments is not only a grand scientific challenge, but also in great practical needs for systematically improving the performance of organic optoelectronic devices. In this work, we will present the first combinatorial bandgap design map over 780 different copolymer donor materials with their targeted optical bandgap values effectively covering the entire solar spectrum from the infrared, visible, to ultraviolet regions. Novel electron acceptor materials are constructed with full flexibility in both the orbital alignments and functional side-group additions beyond the commonly used fullerene-based structures. All of these new materials designs are made possible through breaking the charge conjugation symmetry (CCS) in the underlying electron-phonon couplings that are intrinsic to these ?-conjugated systems. Combined with empirical arguments widely acknowledged in the literature, new ?-conjugated structures are identified with the optimal power conversion efficiencies for both single- and tandem-cells.

  10. In-Vessel Coil Material Failure Rate Estimates for ITER Design Use

    SciTech Connect

    L. C. Cadwallader

    2013-01-01

    The ITER international project design teams are working to produce an engineering design for construction of this large tokamak fusion experiment. One of the design issues is ensuring proper control of the fusion plasma. In-vessel magnet coils may be needed for plasma control, especially the control of edge localized modes (ELMs) and plasma vertical stabilization (VS). These coils will be lifetime components that reside inside the ITER vacuum vessel behind the blanket modules. As such, their reliability is an important design issue since access will be time consuming if any type of repair were necessary. The following chapters give the research results and estimates of failure rates for the coil conductor and jacket materials to be used for the in-vessel coils. Copper and CuCrZr conductors, and stainless steel and Inconel jackets are examined.

  11. Los Alamos National Laboratory new generation standard nuclear material storage container - the SAVY4000 design

    SciTech Connect

    Stone, Timothy Amos [Los Alamos National Laboratory

    2010-01-01

    Incidents involving release of nuclear materials stored in containers of convenience such as food pack cans, slip lid taped cans, paint cans, etc. has resulted in defense board concerns over the lack of prescriptive performance requirements for interim storage of nuclear materials. Los Alamos National Laboratory (LANL) has shared in these incidents and in response proactively moved into developing a performance based standard involving storage of nuclear material (RD003). This RD003 requirements document has sense been updated to reflect requirements as identified with recently issued DOE M 441.1-1 'Nuclear Material Packaging Manual'. The new packaging manual was issued at the encouragement of the Defense Nuclear Facilities Safety Board with a clear directive for protecting the worker from exposure due to loss of containment of stored materials. The Manual specifies a detailed and all inclusive approach to achieve a high level of protection; from package design & performance requirements, design life determinations of limited life components, authorized contents evaluations, and surveillance/maintenance to ensure in use package integrity over time. Materials in scope involve those stored outside an approved engineered-contamination barrier that would result in a worker exposure of in excess of 5 rem Committed Effective Does Equivalent (CEDE). Key aspects of meeting the challenge as developed around the SAVY-3000 vented storage container design will be discussed. Design performance and acceptance criteria against the manual, bounding conditions as established that the user must ensure are met to authorize contents in the package (based upon the activity of heat-source plutonium (90% Pu-238) oxide, which bounds the requirements for weapons-grade plutonium oxide), interface as a safety class system within the facility under the LANL plutonium facility DSA, design life determinations for limited life components, and a sense of design specific surveillance program implementation as LANL moves forward into production and use of the SAVY-3000 will all be addressed. The SAVY-3000 is intended as a work horse package for the DOE complex as a vented storage container primarily for plutonium in solid form.

  12. Materials and fractal designs for 3D multifunctional integumentary membranes with capabilities in cardiac electrotherapy.

    PubMed

    Xu, Lizhi; Gutbrod, Sarah R; Ma, Yinji; Petrossians, Artin; Liu, Yuhao; Webb, R Chad; Fan, Jonathan A; Yang, Zijian; Xu, Renxiao; Whalen, John J; Weiland, James D; Huang, Yonggang; Efimov, Igor R; Rogers, John A

    2015-03-11

    Advanced materials and fractal design concepts form the basis of a 3D conformal electronic platform with unique capabilities in cardiac electrotherapies. Fractal geometries, advanced electrode materials, and thin, elastomeric membranes yield a class of device capable of integration with the entire 3D surface of the heart, with unique operational capabilities in low power defibrillation. Co-integrated collections of sensors allow simultaneous monitoring of physiological responses. Animal experiments on Langendorff-perfused rabbit hearts demonstrate the key features of these systems. PMID:25641076

  13. Cyclic material properties at high strain ranges beyond the standard design codes

    NASA Astrophysics Data System (ADS)

    Maile, Karl; Bothe, Klaus; Blind, Dieter; Vazoukis, Georg

    1992-07-01

    Low cycle fatigue tests were performed at characteristic temperatures on materials employed in nuclear piping systems. The influence of strain rate, temperature, surface roughness, notches and welding on the number of cycles to crack initiation and failure were investigated in the high strain range regime. The crack initiation does not depend significantly on the strain rate, the surface conditions and the temperature. The fatigue endurance of notched specimens cannot be satisfactorily compared with that of smooth specimens. The influence of welding depends on the material. The results of the smooth specimens lie above the design curves of TRD, KTA and ASME code.

  14. Design and "As Flown" Radiation Environments for Materials in Low Earth Orbits

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; Altstatt, Richard L.; McWilliams, Brett; Koontz, Steven L.

    2006-01-01

    The design estimate for the materials for the International Space Station (ISS) specified in SSP 30512 was a conservative estimate. The environment dose was over estimated. The materials originally qualified for approximately 10-15 years are anticipated to be acceptable for periods of up to 20-30 years based on SSP-30512 or 40-60 years based on 2x SSP-30512. This viewgraph presentation shows charts and graphs that review the altitude, the solar minimum and maximum, and the radiation exposure of other satellite, among other graphics.

  15. Design Features and Capabilities of the First Materials Science Research Rack

    NASA Technical Reports Server (NTRS)

    Pettigrew, P. J.; Lehoczky, S. L.; Cobb, S. D.; Holloway, T.; Kitchens, L.

    2003-01-01

    The First Materials Science Research Rack (MSRR-1) aboard the International Space Station (ISS) will offer many unique capabilities and design features to facilitate a wide range of materials science investigations. The initial configuration of MSRR-1 will accommodate two independent Experiment Modules (EMS) and provide the capability for simultaneous on-orbit processing. The facility will provide the common subsystems and interfaces required for the operation of experiment hardware and accommodate telescience capabilities. MSRR1 will utilize an International Standard Payload Rack (ISPR) equipped with an Active Rack Isolation System (ARIS) for vibration isolation of the facility.

  16. Computational Design of Solar Energy Harvesting Materials Made of Earth-Abundant Elements

    NASA Astrophysics Data System (ADS)

    Sun, Yiyang

    2012-02-01

    Very large-scale deployment of photovoltaic (PV) technology based on both the first and second generation solar cells posts serious questions on the materials supply as they rely on either high-purity and high-quality silicon crystals or rare elements such as indium and tellurium. ``Ancient'' PV materials made of earth-abundant elements, such as oxides and sulfides of copper and iron, have attracted resurgent interests. There is also intensive research devoted to the search for ``modern'' earth-abundant PV materials, with a recent promising example being Cu2ZnSnSe4. Computational approaches play a key role in this endeavor by guiding the screening and optimization of the materials toward high device performance. In this paper, I will focus on two aspects of computational design of earth-abundant PV materials. First, I will discuss the methods for accurately predicting band gaps of semiconductor materials. The emphasis will be on the performance of hybrid functional method on different classes of materials. Based on these understandings, I will discuss how to tune the band gap of a material to match the solar spectrum. For example, one could reduce of the band gap of anatase to 1.5 eV by the chemical codoping approach. Second, I will discuss the methods for accurate computation of defect properties, which is important as the defectiveness is intrinsic to the low-cost synthesized materials. I will introduce a method for calculation of defect formation energies by minimizing the error due to the ``band-gap problem'' of the density functional theory. I will also discuss approaches to mitigating the effects of defects, e.g., by passivation.

  17. COMPARISON OF THE TRADITIONAL STRENGTH OF MATERIALS APPROACH TO DESIGN WITH THE FRACTURE MECHANICS APPROACH

    SciTech Connect

    Z. Ceylan

    2002-04-30

    The objective of this activity is to show that the use of the traditional strength of materials approach to the drip shield and the waste package (WP) designs is bounding and appropriate when compared to the fracture mechanics approach. The scope of this activity is limited to determining the failure assessment diagrams for the two materials at issue: Ti-7 and Alloy 22. This calculation is intended for use in support of the license application design of the drip shield and the WP. This activity is associated with the drip shield and the WP designs. The activity evaluation for work package number P32 12234F2, included in ''Technical Work Plan for: Waste Package Design Description for LA'' (Ref. 1, p. A-6), has determined that the development of this document is subject to ''Quality Assurance Requirements and Description'' requirements. The control of the electronic management of data is accomplished in accordance with the methods specified in Reference 1, Section 10. AP-3.124, ''Design Calculations and Analysis'' (Ref. 2), is used to develop and document the calculation.

  18. Design and "As Flown" Radiation Environments for Materials in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Minow, Joseph; McWilliams, Brett; Altstatt, Richard; Koontz, Steven

    2006-01-01

    A conservative design approach was adopted by the International Space Station Program for specifying total ionizing radiation dose requirements for use in selecting and qualifying materials for construction of the International Space Station. The total ionizing dose design environment included in SSP 30512 Space Station Ionizing Radiation Design Environment is based on trapped proton and electron fluence derived from the solar maximum versions of the AE-8 and AP-8 models, respectively, specified for a circular orbit at 500 km altitude and 51.7 degree inclination. Since launch, the range of altitudes utilized for Space Station operations vary from a minimum of approximately 330 km to a maximum of approximately 405 km with a mean operational altitude less than 400 km. The design environment, therefore, overestimates the radiation environment because the particle flux in the South Atlantic Anomaly is the primary contributor to radiation dose in low Earth orbit and flux within the Anomaly is altitude dependent. In addition, a 2X multiplier is often applied to the design environment to cover effects from the contributions of galactic cosmic rays, solar energetic particle events, geomagnetic storms, and uncertainties in the trapped radiation models which are not explicitly included in the design environment. Application of this environment may give radiation dose overestimates on the order of 1OX to 30X for materials exposed to the space environment, suggesting that materials originally qualified for ten year exposures on orbit may be used for longer periods without replacement. In this paper we evaluate the "as flown" radiation environments derived from historical records of the ISS flight trajectory since launch and compare the results with the SSP 30512 design environment to document the magnitude of the radiation dose overestimate provided by the design environment. "As flown" environments are obtained from application of the AE-8/AP-8 trapped particle models along the ISS flight trajectory including variations in altitude due to decay of the vehicle orbit and periodic reboosts to higher altitudes. In addition, an estimate of the AE-8 model to predict low Earth orbit electron flux (because the radiation dose for thin materials is dominated by the electron component of the radiation environment) is presented based on comparisons of the AE-8 model to measurements of electron integral flux at approximately 850 km from the Medium Energy Proton and Electron Detector on board the NOAA Polar Operational Environmental Satellite.

  19. Design and study of water-soluble positive- and negative-tone imaging materials

    NASA Astrophysics Data System (ADS)

    Havard, Jennifer M.; Pasini, Dario; Frechet, Jean M. J.; Medeiros, David R.; Patterson, Kyle; Yamada, Shintaro; Willson, C. Grant

    1998-06-01

    The interest in imaging materials with improved environmental characteristics has led us to consider imaging formulations coated from and developed in aqueous media, thus avoiding the need for both organic solvents and basic aqueous developer solutions. We have previously reported on the design of several negative-tone resists operating via radiation-induced crosslinking, and while the performance of these negative-tone systems met our basic goals, the resolution that could be achieved was limited due to swelling occurring during development. We now report on various other designs based on polyoxazoline, poly(vinyl alcohol), and methacrylate resins that circumvent this problem with approaches towards both negative- and positive- tone systems.

  20. Development of atomistic models to aid the design of new scintillator materials.

    SciTech Connect

    Doty, F. Patrick; Yang, Pin; Zhou, Xiao Wang

    2010-03-01

    The development of more reliable scintillator materials can significantly advance the gamma-ray detection technology. Scintillator materials such as lanthanum halides (e.g., LaBr{sub 3}, CsBr{sub 3}), elpasolites (e.g., Cs{sub 2}LiLaBr{sub 6}, Cs{sub 2}NaLaBr{sub 6}, and Cs{sub 2}LiLaI{sub 6}), and alkali halides (e.g., CsI, NaI) are extremely brittle. The fracture of the materials is often a problem causing the failure of the devices. Lanthanum halides typically have a hexagonal crystal structure. These materials have highly anisotropic thermal and mechanical properties, and therefore they are likely to fracture under cyclic thermal and mechanical loading conditions. For example, fracture of lanthanum halides is known to occur in the field. Fracture during synthesis also complicates the growth of large lanthanum halide single crystals needed for sensitive radiation detection, and accounts for the high production cost of these materials. Elpasolites can have both cubic and non-cubic crystal structures depending on the constituent elements and composition of the compounds. This provides an opportunity to design cubic elpasolites with more isotropic properties and therefore improved mechanical performances. However, the design of an optimized cubic elpasolite crystal remains elusive because there is a tremendous number of possible elpasolites and the design criterion for cubic crystals is not clear. Alkali halides have cubic crystal structures. Consequently, large CsI and NaI crystals have been grown and used in devices. However, these materials suffer from an aging problem, i.e., the properties decay rapidly over time especially under harsh environment. Unfortunately, the fundamental mechanisms of this aging have not been understood and the path to improve the alkali halide-based scintillators is not developed. Clearly, improved scintillator materials can be achieved via strengthened/toughened lanthanum halides, optimized cubic elpasolites, or new alkali halide-based crystals that are more resistant to aging. Without a fundamental understanding of the atomic origins of the mechanical and the thermodynamic properties of materials, past experimental efforts to develop improved scintillator materials have been prolonged. Here we report our recent progress on the development of atomistic models that can be used to accelerate the discovery of new scintillator materials with improved properties. First, we have developed a novel embedded-ion method interatomic potential approach that analytically addresses the variable charge interactions between atoms in ionic compound material systems. Based on this potential, molecular dynamics simulations have been used to study the mechanical properties of LaBr3 including slip systems, dislocation core structures, and material strength. We have also developed an atomistic model that can already be used to predict crystal structures and to derive crystal stability rules for alkali halides. This model is under further development for prediction of crystal structures of elpasolites. These efforts will facilitate the design of better scintillator materials.

  1. Designing and Evaluating a Scientific Training Program and Virtual Learning Materials

    PubMed Central

    van Raalte, Lisa; Boulay, Rachel

    2014-01-01

    The University of Hawaii's John A. Burns School of Medicine developed a professional development program and virtual learning materials to assist high school science teachers become familiar with laboratory techniques prior to engaging in authentic molecular biology research. The purpose of this paper is to provide an evaluative overview of the program with emphasis on the virtual materials that were designed to employ a blended learning approach to augment offline classroom learning. The virtual learning materials provide a unique sphere for scientific learning in which skills can be reproduced in an offline environment. Twelve high school science teachers participated in the training program and were given full access to the online materials. After participation in the program, teachers filled out a final survey and completed a final written reflective statement as a form of evaluating the program and online materials. Thematic analysis was used to code participants' responses. Results showed that teachers recounted meeting the scientists as a valuable experience, teachers were grateful to learn real-world application of current research, and teachers described the importance of learning skills to prepare students to succeed in higher education. Additionally, results showed teacher's intent to use the virtual learning materials as homework tools and in classroom lessons. PMID:24524091

  2. Collection, processing, and reporting of damage tolerant design data for non-aerospace structural materials

    NASA Technical Reports Server (NTRS)

    Huber, P. D.; Gallagher, J. P.

    1994-01-01

    This report describes the organization, format and content of the NASA Johnson damage tolerant database which was created to store damage tolerant property data for non aerospace structural materials. The database is designed to store fracture toughness data (K(sub IC), K(sub c), J(sub IC) and CTOD(sub IC)), resistance curve data (K(sub R) VS. delta a (sub eff) and JR VS. delta a (sub eff)), as well as subcritical crack growth data (a vs. N and da/dN vs. delta K). The database contains complementary material property data for both stainless and alloy steels, as well as for aluminum, nickel, and titanium alloys which were not incorporated into the Damage Tolerant Design Handbook database.

  3. An instrument design concept to minimize creep ringing during step-stress experiments with viscoelastic materials

    NASA Astrophysics Data System (ADS)

    Chan, Hubert K.; Mohraz, Ali

    2014-07-01

    A common observation in step-stress rheological measurements on viscoelastic materials is the prevalence of early stage strain oscillations, which result from a coupling between the measuring system's inertia and the sample's elasticity. This phenomenon, conventionally known as creep ringing, is generally undesirable because it can mask the material's inherent microstructural response to an external stress. In this work, we show how this undesirable effect can be dramatically suppressed in a custom-built shear cell designed for rheo-optical experiments. Using a combined theoretical/experimental approach, we demonstrate that the suppression of creep ringing is due to a low moment of inertia for the measuring system and a unique design concept, in which the torque source is coupled to the sample through a viscous transfer fluid.

  4. A method for developing design diagrams for ceramic and glass materials using fatigue data

    NASA Technical Reports Server (NTRS)

    Heslin, T. M.; Magida, M. B.; Forrest, K. A.

    1986-01-01

    The service lifetime of glass and ceramic materials can be expressed as a plot of time-to-failure versus applied stress whose plot is parametric in percent probability of failure. This type of plot is called a design diagram. Confidence interval estimates for such plots depend on the type of test that is used to generate the data, on assumptions made concerning the statistical distribution of the test results, and on the type of analysis used. This report outlines the development of design diagrams for glass and ceramic materials in engineering terms using static or dynamic fatigue tests, assuming either no particular statistical distribution of test results or a Weibull distribution and using either median value or homologous ratio analysis of the test results.

  5. New Organic Second-Order Nonlinear Optical Materials Developed By Using The Molecular Design Method

    NASA Astrophysics Data System (ADS)

    Itoh, Yuzo; Oono, Kayo; Isogai, Masato; Kakuta, Atsushi

    1989-03-01

    A molecular design method of second-order nonlinear optical materials for SHG device applications of diode lasers is proposed. The method consists of a semi-empirical MO calculation (CNDO/S3-CI) to evaluate molecular nonlinear optical properties, i.e. hyperpolarizability and the lowest excited energy, and an intermolecular interaction energy calculation to evaluate its crystallization property, in particular whether it crystallizes in a centrosymmetric structure or not. In the latter calculation, the empirical atom-atom pairwise potential functions, for example Lennard-Jones type, are used to evaluate intermolecular interaction energy of two molecules or the crystal energy. Using this method we design and synthesized novel second-order nonlinear optical materials for our target applications: xanthone and benzophenone derivatives which have relatively large optical nonlinearity and very short absorption cut-off wavelength.

  6. Evaluation of critical materials for five advanced design photovoltaic cells with an assessment of indium and gallium

    Microsoft Academic Search

    R. L. Watts; W. E. Gurwell; W. M. Jamieson; L. W. Long; W. T. Pawlewicz; S. A. Smith; R. R. Teeter

    1980-01-01

    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. This report presents the results of the screening of the five following advanced PV cell designs: polycrystalline silicon,

  7. An Analysis of Teaching Competence in Science Teachers Involved in the Design of Context-Based Curriculum Materials

    ERIC Educational Resources Information Center

    De Putter-Smits, Lesley G. A.; Taconis, Ruurd; Jochems, Wim; Van Driel, Jan

    2012-01-01

    The committees for the current Dutch context-based innovation in secondary science education employed teachers to design context-based curriculum materials. A study on the learning of science teachers in design teams for context-based curriculum materials is presented in this paper. In a correlation study, teachers with (n = 5 and 840 students)…

  8. 75 FR 39523 - Notice of Intent: Designation of an Ocean Dredged Material Disposal Site (ODMDS) Off the Mouth of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-09

    ...Designation of an Ocean Dredged Material Disposal Site (ODMDS) Off the Mouth of the St...mouth of the St. Johns River for the disposal of dredged material from the Jacksonville...as not designating an additional ocean disposal site. The existing Jacksonville...

  9. 77 FR 63312 - Notice of Intent: Designation of an Ocean Dredged Material Disposal Site (ODMDS) in Eastern Long...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-16

    ...Designation of an Ocean Dredged Material Disposal Site (ODMDS) in Eastern Long Island...of one or more Ocean Dredged Material Disposal Sites (ODMDS) to serve the eastern...Environmental Policy Act documents for all ocean disposal site designations. The SEIS will...

  10. Design and material variation for an improved power output of AMTEC cells

    Microsoft Academic Search

    M. A. K Lodhi; A Daloglu

    2001-01-01

    A number of design changes for improving the alkali metal thermo-electric converter (AMTEC) cell performance are investigated. In this study, both the material used in AMTEC cell and the dimensions of the cell are changed at the same time. Two different hot side temperatures, Thot=1173K and Thot=1023K, are tested. The condenser temperature, Tcond, is kept at 623K. Results show that

  11. Package design and materials selection optimization for overmolded flip chip packaging

    Microsoft Academic Search

    Yaomin Lin; Frank G. Shi

    2006-01-01

    In overmolded flip chip (OM-FC) packaging, interface delamination-particularly at the die\\/underfill interface-is often expected to be a main type of failure mode. In this paper, a systematic stress analysis is performed by means of numerical simulations for the optimal design of package geometries and materials combinations. The behavior of the interfacial stresses at the die\\/underfill and die\\/mold-compound (MC) during the

  12. Simultaneous Design Optimization of Permanent Magnet, Coils, and Ferromagnetic Material in Actuators

    Microsoft Academic Search

    Jaewook Lee; Ercan M. Dede; Tsuyoshi Nomura

    2011-01-01

    This paper presents structural topology optimization of an electro\\/permanent magnet linear actuator. The optimization goal is to maximize the average magnetic force acting on a plunger that travels over a distance of 20 mm. To achieve this goal, the magneticfield sources (i.e., permanent magnet, positive and negative direction coils), and ferromagnetic material of the yoke are simultaneously co-designed using four

  13. Standardization Efforts for Mechanical Testing and Design of Advanced Ceramic Materials and Components

    NASA Technical Reports Server (NTRS)

    Salem, Jonathan A.; Jenkins, Michael G.

    2003-01-01

    Advanced aerospace systems occasionally require the use of very brittle materials such as sapphire and ultra-high temperature ceramics. Although great progress has been made in the development of methods and standards for machining, testing and design of component from these materials, additional development and dissemination of standard practices is needed. ASTM Committee C28 on Advanced Ceramics and ISO TC 206 have taken a lead role in the standardization of testing for ceramics, and recent efforts and needs in standards development by Committee C28 on Advanced Ceramics will be summarized. In some cases, the engineers, etc. involved are unaware of the latest developments, and traditional approaches applicable to other material systems are applied. Two examples of flight hardware failures that might have been prevented via education and standardization will be presented.

  14. Preliminary Design of a Galactic Cosmic Ray Shielding Materials Testbed for the International Space Station

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Berkebile, Stephen; Sechkar, Edward A.; Panko, Scott R.

    2012-01-01

    The preliminary design of a testbed to evaluate the effectiveness of galactic cosmic ray (GCR) shielding materials, the MISSE Radiation Shielding Testbed (MRSMAT) is presented. The intent is to mount the testbed on the Materials International Space Station Experiment-X (MISSE-X) which is to be mounted on the International Space Station (ISS) in 2016. A key feature is the ability to simultaneously test nine samples, including standards, which are 5.25 cm thick. This thickness will enable most samples to have an areal density greater than 5 g/sq cm. It features a novel and compact GCR telescope which will be able to distinguish which cosmic rays have penetrated which shielding material, and will be able to evaluate the dose transmitted through the shield. The testbed could play a pivotal role in the development and qualification of new cosmic ray shielding technologies.

  15. Design, fabrication and characterization of a monolithic focusing piezoceramic transducer for an anisotropic material.

    PubMed

    Souris, Fabien; Grucker, Jules; Garroum, Nabil; Leclercq, Arnaud; Isac, Jean-Michel; Dupont-Roc, Jacques; Jacquier, Philippe

    2014-06-01

    Piezoceramic transducers shaped as spherical caps are widely used to focus ultrasound waves in isotropic materials. For anisotropic materials, the sound wave surface is not spherical and the transducer surface should be adjusted to reproduce a portion of this wave surface to focus the emitted sound properly. In this article, we show how to design such a transducer and how to fabricate it in lab on a standard machine from a rod of raw piezo ceramic material. The main features of its electrical impedance response are well reproduced by a numerical model, allowing the identification of most of its vibrational modes. We finally measured the sound field emitted by such a transducer and found its focusing efficiency similar to that of spherical caps in isotropic media. PMID:24985837

  16. Design and operation of a remotely operated plutonium waste size reduction and material handling process

    SciTech Connect

    Stewart, III, J A; Charlesworth, D L

    1986-01-01

    Noncombustible /sup 238/Pu and /sup 239/Pu waste is generated as a result of normal operation and decommissioning activity at the Savannah River Plant, and is being retrievably stored there. As part of the long-term plant to process the stored waste and current waste for permanent disposal, a remote size reduction and material handling process is being cold-tested at Savannah River Laboratory. The process consists of a large, low-speed shredder and material handling system, a remote worktable, a bagless transfer system, and a robotically controlled manipulator. Initial testing of the shredder and material handling system and a cycle test of the bagless transfer system has been completed. Fabrication and acceptance testing of the Telerobat, a robotically controlled manipulator has been completed. Testing is scheduled to begin in 3/86. Design features maximizing the ability to remotely maintain the equipment were incorporated. Complete cold-testing of the equipment is scheduled to be completed in 1987.

  17. Mechanical investigation of fibre reinforced materials for superconducting poloidal field coil design

    NASA Astrophysics Data System (ADS)

    Nyilas, A.; Jeske, U.

    This Paper reports the results of flexural and shear measurements of fibre reinforced plastic materials. The materials tested were carbon fibre reinforced plastics (CFRP) and glass fibre reinforced plastics (GFRP). The objectives of the tests were to determine the mechanical properties of the industrially manufactured thick walled structures. The rectangular hollow section made of CFRP material produced has a wall thickness of ?30 mm. The anisotropic characteristics of the flexural properties were determined at ambient temperature and at 77 K. In addition, pultruded GFRP complex shaped sections were measured with respect to their mechanical behaviour. Results on the thermal shrinkage measurements of CFRP- and GFRP-structures are also reported. An evaluation of the data and their impact on design were discussed under the consideration of superconducting poloidal field coil aspects.

  18. [Spectrum analysis methods of protein adsorption and design of biomedical materials].

    PubMed

    Xu, Dong; Zhou, Ning-Lin; Shen, Jian

    2010-12-01

    Protein absorption happens firstly when biological materials contact environment of organisms. The competitive adsorption behavior of different protein and the impact of biomaterial surfaces characteristics on protein adsorption are summarized. Materials with small surface free energy, high hydrophility, and a negative charge, or with the presence of micro-phase separation structure are able to reduce fibrinogen adsorption, showing good anti-clotting properties. FTIR, CD, NMR and FL are applied in protein adsorption analysis. XPS, Raman, AFM and other modern instruments have also emerged in this area. QCM appears to be more intuitive in the study of protein adsorption mechanism. The development of study on protein adsorption would guide the design of biomedical materials. PMID:21322223

  19. Information management in the design of materials control and accountability systems

    SciTech Connect

    Whitty, W.J.; Markin, J.T.; Strittmatter, R.B.

    1988-01-01

    This paper presents information management methods for materials accounting systems based on experience in systems development at DOE facilities. We describe principles for the acquistion and organization of data for a materials control and accountability (MC and A) system. Many of these principles are drawn from software engineering. These include the preparation of a requirements document, a functional specification, and the application of structured analysis and design. Insufficient effort and detail to these early fundamental activities for identifying and acquiring the appropriate data cause many problems later. Failure to provide for complete acquisition of all required information leads to potentially costly revisions to the data acquisition system or to a materials accounting system that cannot complete its intended functions. Likewise, unrealistic analyses requirements can cause catastrophic problems later on. 16 refs.

  20. Conceptual design report: Nuclear materials storage facility renovation. Part 3, Supplemental information

    SciTech Connect

    NONE

    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. It is organized into seven parts. Part I - Design Concept describes the selected solution. Part III - Supplemental Information contains calculations for the various disciplines as well as other supporting information and analyses.

  1. CAD/CAM (Computer Aided Design/Computer Aided Manufacture). A Brief Guide to Materials in the Library of Congress.

    ERIC Educational Resources Information Center

    Havas, George D.

    This brief guide to materials in the Library of Congress (LC) on computer aided design and/or computer aided manufacturing lists reference materials and other information sources under 13 headings: (1) brief introductions; (2) LC subject headings used for such materials; (3) textbooks; (4) additional titles; (5) glossaries and handbooks; (6)…

  2. Design, crystal growth, and physical properties of low-temperature thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Fuccillo, Michael K.

    Thermoelectric materials serve as the foundation for two important modern technologies, namely 1) solid-state cooling, which enables small-area refrigeration without vibrations or moving parts, and 2) thermoelectric power generation, which has important implications for waste heat recovery and improved sources of alternative energy. Although the overall field of thermoelectrics research has been active for decades, and several consumer and industrial products have already been commercialized, the design and synthesis of new thermoelectrics that outperform long-standing state of the art materials has proven extremely challenging. This is particularly true for low-temperature refrigeration applications, which is the focus of this work; however, scientific advances in this area generally support power generation as well. In order to achieve more efficient materials for virtually all thermoelectric applications, improved materials design principles must be developed and synthetic procedures must be better understood. We aim to contribute to these goals by studying two classes of materials, namely 1) the tetradymites Bi2TeSe 2 and Bi2Te2Se, which are close relatives of state of the art thermoelectric cooling materials, and 2) Kondo insulating (-like) FeSb2 and FeSi, which possess anomalously enhanced low-temperature thermoelectric properties that arise from exotic electronic and magnetic properties. The organization of this dissertation is as follows: Chapter 1 is a brief perspective on solid-state chemistry. Chapter 2 presents experimental methods for synthesizing and characterizing thermoelectric materials. In Chapter 3, two original research projects are discussed: first, work on the tetradymite Bi2TeSe2 doped with Sb to achieve an n- to p-type transition, and second, the tetradymite Bi2Te2Se with chemical defects through two different methods. Chapter 4 gives the magnetic and transport properties of FeSb 2--RuSb2 alloys, a family of compounds exemplifying what we consider to be the next generation of thermoelectric materials for low-temperature cooling due to their anomalously enhanced low-temperature thermoelectric properties, along with an outlook for seeking additional materials with similarly enhanced properties. Lastly, in Chapter 5, a brief outlook on the future of thermoelectrics is discussed, along with our current and future work on FeSi-RuSi alloys.

  3. Design of a broadband ?-negative planar material with low frequency dispersion

    NASA Astrophysics Data System (ADS)

    Tang, Ming-Chun; Xiao, Shaoqiu; Deng, Tianwei; Wang, Yan; Bai, Yanying; Liu, Changrong; Shang, Yuping; Xiong, Jiang; Wang, Bingzhong

    2012-03-01

    Compared with the traditional split-ring resonator reported by Pendry et al. (IEEE Trans. Microw. Theory Tech. 47:2075, 1999), the co-directional split-ring resonator, which has inherent low mutual coupling between its outer and inner rings, can provide distinct dual-band magnetic resonances. In this paper, we analyzed and compared different types of split-ring resonator, but selected the co-directional split-ring resonator for the tri-band magnetic resonator design because of its attractive dual-band magnetic resonance characteristics. We then accommodated the rings' resonant strengths in the co-directional split-ring resonator to be nearly equal, and added an arm-loaded ring to design a new tri-band magnetic resonator. Finally, we designed and experimentally demonstrated a broadband ?-negative planar material with low frequency dispersion, which consisted of three pairs of tri-band magnetic resonators with slightly different dimensions.

  4. Ten different hip resurfacing systems: biomechanical analysis of design and material properties

    PubMed Central

    Kleinhans, Jennifer A.; Menge, Michael; Kretzer, Jan Philippe

    2008-01-01

    This study gives an overview of the main macro- and microstructural differences of ten commercially available total hip resurfacing implants. The heads and cups of resurfacing hip implants from ten different manufacturers were analysed. The components were measured in a coordinate measuring machine. The microstructure of the heads and cups was inspected by scanning electron microscopy. The mean radial clearance was 84.86 ?m (range: 49.47–120.93 ?m). The implants were classified into three groups (low, medium and high clearance). All implants showed a deviation of roundness of less than 10 ?m. It was shown that all implants differ from each other and a final conclusion about the ideal design and material combination cannot be given based on biomechanical data. Widespread use of specific designs can only be recommended if clinical long-term follow-up studies are performed and analysed for each design. PMID:18600323

  5. PREFACE: International Conference on Advanced Structural and Functional Materials Design 2008

    NASA Astrophysics Data System (ADS)

    Kakeshita, Tomoyuki

    2009-07-01

    The Ministry of Education, Culture, Sports, Science and Technology of Japan started the Priority Assistance for the Formation of Worldwide Renowned Centers of Research - Global COE Program. This program is based on the competitive principle where a third party evaluation decides which program to support and to give priority support to the formation of world-class centers of research. Our program Center of Excellence for Advanced Structural and Functional Materials Design was selected as one of 13 programs in the field of Chemistry and Materials Science. This center is composed of two materials-related Departments in the Graduate School of Engineering: Materials and Manufacturing Science and Adaptive Machine Systems, and 4 Research Institutes: Center for Atomic and Molecular Technologies, Welding and Joining Research Institute, Institute of Scientific and Industrial Research and Research Center for Ultra-High Voltage Electron Microscopy. Recently, materials research, particularly that of metallic materials, has specialized only in individual elemental characteristics and narrow specialty fields, and there is a feeling that the original role of materials research has been forgotten. The 6 educational and research organizations which make up the COE program cooperatively try to develop new advanced structural and functional materials and achieve technological breakthrough for their fabrication processes from electronic, atomic, microstructural and morphological standpoints, focusing on their design and application: development of high performance structural materials such as space plane and turbine blades operating under a severe environment, new fabrication and assembling methods for electronic devices, development of evaluation technique for materials reliability, and development of new biomaterials for regeneration of biological hard tissues. The aim of this international conference was to report the scientific progress in our Global COE program and also to discuss related research topics. The organizing committee gratefully thanks participants for presenting their recent results and for discussions with our COE members and international attendees. November 2008 Professor Tomoyuki Kakeshita Chairman of the Conference Vice Dean, Graduate School of Engineering, Osaka University, Division of Materials and Manufacturing Science, Graduate School of Engineering Leader of Global COE Program, Osaka University, ''Center of Excellence for Advanced Structural and Functional Materials Design'' Organization Chairman: T Kakeshita (Osaka University) Advisory Board:H Mehrer (University Münster, Germany), E K H Salje (University of Cambridge, United Kingdom), H-E Schaefer (University of Stuttgart, Germany), P Veyssiere (CNRS-ONERA, France) Organizing Committee: T Kakeshita, H Araki, H Fujii, S Fujimoto, Y Fujiwara, A Hirose, S Kirihara, M Mochizuki, H Mori, T Nagase, H Nakajima, T Nakano, R Nakatani, K Nogi, Y Setsuhara, Y Shiratsuchi, T Tanaka, T Terai, H Tsuchiya, N Tsuji, H Utsunomiya, H Yasuda, H Yasuda (Osaka University) Executive Committee: T Kakeshita, S Fujimoto, Y Fujiwara, A Hirose, T Tanaka, H Yasuda (Osaka University) Conference Secretariat: Y Fujiwara (Osaka University) Proceedings Editors: T Kakeshita and Y Fujiwara (Osaka University) Conference photograph

  6. Conceptual design report: Nuclear materials storage facility renovation. Part 6, Alternatives study

    SciTech Connect

    NONE

    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 material 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 report is organized according to the sections and subsections outlined by Attachment 111-2 of DOE Document AL 4700.1, Project Management System. It is organized into seven parts. This document, Part VI - Alternatives Study, presents a study of the different storage/containment options considered for NMSF.

  7. Quantum Dot Intermediate Band Solar Cells: Design Criteria and Optimal Materials

    NASA Astrophysics Data System (ADS)

    Jenks, Steven Evans

    The main limitation of the conventional solar conversion device is that low energy photons cannot. excite charge carriers to the conduction band, therefore do not contribute to the devices's current, and high energy photons are not efficiently used due to a poor match of the solar spectrum to the energy gap. However, if intermediate levels are introduced into the energy gap of a conventional device, then low energy photons can be used to promote charge carriers in a stepwise mariner to the conduction band thereby enhancing the current while maintaining a large open-circuit voltage. This concept is called the intermediate band solar cell and increases the efficiency beyond the thermodynamic limits of the conventional device. A device based on the confined electron levels of quantum dots called the quantum dot intermediate band solar cell is a physical realization of the intermediate band solar cell. In this work, we propose design criteria and optimal material systems that are considered candidates for the quantum dot intermediate band solar cell. To search for optimal materials. the finite element method is developed and MATLAB code is designed in the context of quantum and continuum mechanics with the sophistication necessary to allow for three dimensional numerical simulations that incorporate realistic assumptions about the quantum dot. The materials considered in this work are the technologically important III-V compound semiconductors and their alloys. Numerical simulations are carried out on quantum dot geometries that have been experimentally observed during self-assembled growth, the technology proposed to achieve the quantum dot intermediate band solar cell, and those material systems that have properties that match those of the intermediate band solar cell with efficiency greater than 46% for unconcentrated light and greater than 62% for fully concentrated light are identified as optimal materials for the quantum dot intermediate band solar cell.

  8. How to solve materials and design problems in solar heating and cooling, Energy Technology Review No. 77

    Microsoft Academic Search

    D. S. Ward; H. S. Oberoi; S. D. Weinstein

    1982-01-01

    Difficulties encountered in active and passive solar space heating systems and active solar space cooling systems are reported. The problems include design errors, installation mistakes, inadequate durability of materials, unacceptable reliability of components, and wide variations in performance of operation of different solar systems. Feedback from designers and manufacturers involved in the solar market is summarized. The designers' experiences with

  9. Rational design of metal nitride redox materials for solar-driven ammonia synthesis.

    PubMed

    Michalsky, Ronald; Pfromm, Peter H; Steinfeld, Aldo

    2015-06-01

    Fixed nitrogen is an essential chemical building block for plant and animal protein, which makes ammonia (NH3) a central component of synthetic fertilizer for the global production of food and biofuels. A global project on artificial photosynthesis may foster the development of production technologies for renewable NH3 fertilizer, hydrogen carrier and combustion fuel. This article presents an alternative path for the production of NH3 from nitrogen, water and solar energy. The process is based on a thermochemical redox cycle driven by concentrated solar process heat at 700-1200°C that yields NH3 via the oxidation of a metal nitride with water. The metal nitride is recycled via solar-driven reduction of the oxidized redox material with nitrogen at atmospheric pressure. We employ electronic structure theory for the rational high-throughput design of novel metal nitride redox materials and to show how transition-metal doping controls the formation and consumption of nitrogen vacancies in metal nitrides. We confirm experimentally that iron doping of manganese nitride increases the concentration of nitrogen vacancies compared with no doping. The experiments are rationalized through the average energy of the dopant d-states, a descriptor for the theory-based design of advanced metal nitride redox materials to produce sustainable solar thermochemical ammonia. PMID:26052421

  10. Soft network composite materials with deterministic and bio-inspired designs

    NASA Astrophysics Data System (ADS)

    Jang, Kyung-In; Chung, Ha Uk; Xu, Sheng; Lee, Chi Hwan; Luan, Haiwen; Jeong, Jaewoong; Cheng, Huanyu; Kim, Gwang-Tae; Han, Sang Youn; Lee, Jung Woo; Kim, Jeonghyun; Cho, Moongee; Miao, Fuxing; Yang, Yiyuan; Jung, Han Na; Flavin, Matthew; Liu, Howard; Kong, Gil Woo; Yu, Ki Jun; Rhee, Sang Il; Chung, Jeahoon; Kim, Byunggik; Kwak, Jean Won; Yun, Myoung Hee; Kim, Jin Young; Song, Young Min; Paik, Ungyu; Zhang, Yihui; Huang, Yonggang; Rogers, John A.

    2015-03-01

    Hard and soft structural composites found in biology provide inspiration for the design of advanced synthetic materials. Many examples of bio-inspired hard materials can be found in the literature; far less attention has been devoted to soft systems. Here we introduce deterministic routes to low-modulus thin film materials with stress/strain responses that can be tailored precisely to match the non-linear properties of biological tissues, with application opportunities that range from soft biomedical devices to constructs for tissue engineering. The approach combines a low-modulus matrix with an open, stretchable network as a structural reinforcement that can yield classes of composites with a wide range of desired mechanical responses, including anisotropic, spatially heterogeneous, hierarchical and self-similar designs. Demonstrative application examples in thin, skin-mounted electrophysiological sensors with mechanics precisely matched to the human epidermis and in soft, hydrogel-based vehicles for triggered drug release suggest their broad potential uses in biomedical devices.

  11. Designing and Evaluating the Effectiveness of Physlet-Based Learning Materials in Supporting Conceptual Learning in Secondary School Physics

    NASA Astrophysics Data System (ADS)

    Ülen, Simon; ?agran, Branka; Slavinec, Mitja; Gerli?, Ivan

    2014-10-01

    Many educational researchers have investigated how best to support conceptual learning in science education. In this study, the aim was to design learning materials using Physlets, small computer simulations, and to evaluate the effectiveness of these materials in supporting conceptual learning in secondary school physics. Students were taught in two different physics courses (conditions): one group of students ( n = 40) was taught using Physlet-based learning materials, and the other ( n = 40) was taught using expository instruction. To evaluate the designed materials, we assessed students' thinking skills in relation to physics after the course and analyzed the results using an independent t test, multiple regression analyses, and one-way analysis of covariance. The results showed better thinking skills among students in the experimental group and supported a clear relationship between the physics course using Physlet-based materials and this improvement ( p < 0.05). These results indicate that properly designed Physlet-based materials can effectively support conceptual learning.

  12. Conceptual design report: Nuclear materials storage facility renovation. Part 7, Estimate data

    SciTech Connect

    NONE

    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 report is organized according to the sections and subsections outlined by Attachment III-2 of DOE Document AL 4700.1, Project Management System. It is organized into seven parts. This document, Part VII - Estimate Data, contains the project cost estimate information.

  13. Using experimental design modules for process characterization in manufacturing/materials processes laboratories

    NASA Technical Reports Server (NTRS)

    Ankenman, Bruce; Ermer, Donald; Clum, James A.

    1994-01-01

    Modules dealing with statistical experimental design (SED), process modeling and improvement, and response surface methods have been developed and tested in two laboratory courses. One course was a manufacturing processes course in Mechanical Engineering and the other course was a materials processing course in Materials Science and Engineering. Each module is used as an 'experiment' in the course with the intent that subsequent course experiments will use SED methods for analysis and interpretation of data. Evaluation of the modules' effectiveness has been done by both survey questionnaires and inclusion of the module methodology in course examination questions. Results of the evaluation have been very positive. Those evaluation results and details of the modules' content and implementation are presented. The modules represent an important component for updating laboratory instruction and to provide training in quality for improved engineering practice.

  14. Corrosion test plan to guide canister material selection and design for a tuff repository

    SciTech Connect

    McCright, R.D.; van Konynenburg, R.A.; Ballou, L.B.

    1983-11-01

    Corrosion rates and the mode of corrosion attack form a most important basis for selection of canister materials and design of a nuclear waste package. Type 304L stainless steel was selected as the reference material for canister fabrication because of its generally excellent corrosion resistance in water, steam and air. However, 304L may be susceptible to localized and stress-assisted forms of corrosion under certain conditions. Alternative alloys are also investigated; these alloys were chosen because of their improved resistance to these forms of corrosion. The fabrication and welding processes, as well as the glass pouring operation for defense and commercial high-level wastes, may influence the susceptibility of the canister to localized and stress forms of corrosion. 12 references, 2 figures, 4 tables.

  15. Design and Implementation of a Facility for Discovering New Scintillator Materials

    SciTech Connect

    Derenzo, Stephen; Derenzo, Stephen E; Boswell, Martin S.; Bourret-Courchesne, Edith; Boutchko, Rostyslav; Budinger, Thomas F.; Canning, Andrew; Hanrahan, Stephen M.; Janecek, Martin; Peng, Qiyu; Porter-Chapman, Yetta; Powell, James; Ramsey, Christopher A.; Taylor, Scott E.; Wang, Lin-Wang; Weber, Marvin J.; Wilson, David S.

    2008-04-25

    We describe the design and operation of a high-throughput facility for synthesizing thousands of inorganic crystalline samples per year and evaluating them as potential scintillation detector materials. This facility includes a robotic dispenser, arrays of automated furnaces, a dual-beam X-ray generator for diffractometery and luminescence spectroscopy, a pulsed X-ray generator for time response measurements, computer-controlled sample changers, an optical spectrometer, and a network-accessible database management system that captures all synthesis and measurement data.

  16. Space processing of electronic materials. [determining ther themal conductivity of mercury cadmium tellurides and furnace design

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Holland, L. R.

    1981-01-01

    The relative values of thermal conductivity of solid and liquid HgCdTe are critically important in the design configuration of the furnaces used for Bridgman crystal growth. The thermal diffusivity of the material is closely linked to the conductivity by the defining relation D = k/rho c, where D is the diffusivity, K is the thermal conductivity, rho is the density, and c is the specific heat. The use of transient and periodic heating approaches to measure the diffusivity are explored. A system for securing and extracting heat from silica or glass tubes under high C vacuum conditions is described.

  17. Materials design for semiconductor spintronics by ab initio electronic-structure calculation

    Microsoft Academic Search

    H. Katayama-Yoshida; K. Sato

    2003-01-01

    A systematic study for the materials design of III–V and II–VI compound-based ferromagnetic diluted magnetic semiconductors is given based on ab initio calculations within the local spin density approximation. The electronic structures of 3d-transition-metal-atom-doped GaN and Mn-doped InN, InP, InAs, InSb, GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs and AlSb were calculated by the Korringa–Kohn–Rostoker method combined with the coherent

  18. Design and characterization of bioceramic coating materials for Ti6Al4V

    Microsoft Academic Search

    Qiang Wei; Zhen-Duo Cui; Xian-Jin Yang; Lian-Yun Zhang; Jia-Yin Deng

    2010-01-01

    Novel bioceramics used as coating materials for Ti6Al4V were designed and characterized by adjusting the thermal expansion\\u000a coefficient. The results show that the thermal expansion coefficient (?) of 6PM-B5-F4 coating is 10.1 × 10?6\\/°C, which matched that of Ti6Al4V. The bonding strength between the alloy and 6PM-B5-F4 coating was further measured by the\\u000a longitudinal pull-off test. The in vitro response

  19. A Multiscale, Nonlinear, Modeling Framework Enabling the Design and Analysis of Composite Materials and Structures

    NASA Technical Reports Server (NTRS)

    Bednarcyk, Brett A.; Arnold, Steven M.

    2011-01-01

    A framework for the multiscale design and analysis of composite materials and structures is presented. The ImMAC software suite, developed at NASA Glenn Research Center, embeds efficient, nonlinear micromechanics capabilities within higher scale structural analysis methods such as finite element analysis. The result is an integrated, multiscale tool that relates global loading to the constituent scale, captures nonlinearities at this scale, and homogenizes local nonlinearities to predict their effects at the structural scale. Example applications of the multiscale framework are presented for the stochastic progressive failure of a SiC/Ti composite tensile specimen and the effects of microstructural variations on the nonlinear response of woven polymer matrix composites.

  20. Multiscale Design of Advanced Materials based on Hybrid Ab Initio and Quasicontinuum Methods

    SciTech Connect

    Luskin, Mitchell [University of Minnesota

    2014-03-12

    This project united researchers from mathematics, chemistry, computer science, and engineering for the development of new multiscale methods for the design of materials. Our approach was highly interdisciplinary, but it had two unifying themes: first, we utilized modern mathematical ideas about change-of-scale and state-of-the-art numerical analysis to develop computational methods and codes to solve real multiscale problems of DOE interest; and, second, we took very seriously the need for quantum mechanics-based atomistic forces, and based our methods on fast solvers of chemically accurate methods.

  1. Silicon-based elementary particle tracking system: Materials science and mechanical engineering design

    SciTech Connect

    Miller, W.O.; Gamble, M.T.; Thompson, T.C.; Hanlon, J.A.

    1993-01-01

    Research and development of the mechanical, cooling, and structural design aspects of a silicon detector-based elementary particle tracking system has been performed. Achieving stringent system precision, stability, and mass requirements necessitated the use of graphite fiber-reinforced cyanate-ester (C-E) resins. Mechanical test results of the effects of butane, ionizing radiation, and a combination of both on the mechanical properties of these materials are presented, as well as progress on developing compression molding of an ultralightweight graphite composite ring structure and TV holography-based noninvasive evaluation.

  2. Silicon-based elementary particle tracking system: Materials science and mechanical engineering design

    SciTech Connect

    Miller, W.O.; Gamble, M.T.; Thompson, T.C.; Hanlon, J.A.

    1993-05-01

    Research and development of the mechanical, cooling, and structural design aspects of a silicon detector-based elementary particle tracking system has been performed. Achieving stringent system precision, stability, and mass requirements necessitated the use of graphite fiber-reinforced cyanate-ester (C-E) resins. Mechanical test results of the effects of butane, ionizing radiation, and a combination of both on the mechanical properties of these materials are presented, as well as progress on developing compression molding of an ultralightweight graphite composite ring structure and TV holography-based noninvasive evaluation.

  3. The structural design of electrode materials for high energy lithium batteries.

    SciTech Connect

    Thackeray, M.; Chemical Sciences and Engineering Division

    2007-01-01

    Lithium batteries are used to power a diverse range of applications from small compact devices, such as smart cards and cellular telephones to large heavy duty devices such as uninterrupted power supply units and electric- and hybrid-electric vehicles. This paper briefly reviews the approaches to design advanced materials to replace the lithiated graphite and LiCoO{sub 2} electrodes that dominate today's lithium-ion batteries in order to increase their energy and safety. The technological advantages of lithium batteries are placed in the context of water-based- and high-temperature battery systems.

  4. Simulation tool for optical design of PET detector modules including scintillator material and sensor array

    SciTech Connect

    Jatekos, B.; Erdei, G.; Lorincz, E. [Budapest Univ. of Technology and Economics, Dept. of Atomic Physics, Budafoki ut 8, H-1111 Budapest (Hungary)

    2011-07-01

    The appearance of single photon avalanche diodes (SPADs) in the field of PET detector modules made it necessary to apply more complex optical design methods to refine the performance of such assemblies. We developed a combined simulation tool that is capable to model complex detector structures including scintillation material, light guide, light collection optics and sensor, correctly taking into account the statistical behavior of emission of scintillation light and its absorbance in SPADs. As a validation we compared simulation results obtained by our software and another optical design program. Calculations were performed for a simple PET detector arrangement used for testing purposes. According to the results, deviation of center of gravity coordinates between the two simulations is 0.0195 mm, the average ratio of total counts 1.0052. We investigated the error resulting from finite sampling in wavelength space and we found that 20 nm pitch is sufficient for the simulation in case of the given spectral dependencies. (authors)

  5. The Roles of Materials, Processing, and Design in Quantum Information Circuits

    NASA Astrophysics Data System (ADS)

    Pappas, David

    2015-03-01

    Significant progress has been made in the coherence of superconducting circuits for resonators and qubits. Over the last decade, the importance of loss and decoherence from defects at interfaces and on surfaces has been recognized and mitigated by optimizing the materials and minimizing their participation in the circuit. This has resulted in novel new designs for quantum circuits, both 3D and 2D circuits. Some or our new designs will be discussed, and these developments will be compared and contrasted to ongoing surface science studies of ion traps that has resulted in improved operations with two orders of magnitude lower heating rates. This work has been supported by DARPA, the Laboratory for Physical Sciences, and the NIST Quantum Information Initiative

  6. Blanc, I., Peuportier, B., "Eco-design of buildings and comparison of materials", In Proceedings of the 1 international seminar on Society & materials, SAM1, [CD ROM], 6-7 mars 2007, Sville, Spain, European

    E-print Network

    Paris-Sud XI, Université de

    Blanc, I., Peuportier, B., "Eco-design of buildings and comparison of materials", In Proceedings Commission DG Joint Research Centre 1/8 ECO-DESIGN OF BUILDINGS AND COMPARISON OF MATERIALS I. Blanc, B are highly related to the choice of building materials. Eco-design requires therefore a relevant inte- grated

  7. Metal-insulator-metal diodes towards THz and optical energy harvesting: Development of materials design principles

    NASA Astrophysics Data System (ADS)

    Periasamy, Prakash

    Metal-Insulator-Metal (MIM) structures are attractive candidates for high-frequency rectification applications such as THz imaging and sensors, and infrared/visible energy harvesting (rectenna) devices. This thesis develops materials selection principles to guide the choice of material pairs for MIM stacks with desired rectification performance. In particular, a first-of-its kind MIM materials space map is developed that correlates materials properties to rectification performance for different MIM combinations. The materials space diagram is generated based on systematic experimental studies that explore the role of both the metals and the insulator in the MIM stack in determining MIM device performance by evaluating the current-voltage response of a combinatorial set of MIM materials at low frequencies. A novel modified point-contact geometry is developed to rapidly examine a number of MIM material combinations. Material properties such as work function (phiM) of the metals and electron affinity (chi) of the insulator, as well as the thermodynamic chemical stability of the interface are identified as crucial elements for MIM materials selection. Investigations performed to identify the role of metals revealed that it is sufficient to choose the metals such that their Deltaphi is > ~ 300 meV to achieve desired rectification characteristics (high asymmetry and nonlinearity). Using the Nb/Nb2O5 bilayer as the model system, the asymmetry and the nonlinearity were found to be only weakly dependent on Deltaphi above ˜ 0.4 eV. A hypothesis is developed and tested that guides the insulator selection criteria. The proposed hypothesis states that, "to minimize the turn-on voltage and maximize asymmetry and nonlinearity, the electron affinity of the insulator should be close to one of the metal work function values so as to produce a low barrier height". Although the study validated the hypothesis across the material systems studied, preliminary experiments on two additional high potential MIM systems (Hf/TiO2/Pt and Sm/ZrO2/Pt) unexpectedly yielded much lower asymmetry and nonlinearity than predicted by the hypothesis. Thermodynamic and TEM cross-sectional analysis on these systems (Hf/TiO 2 and Sm/ZrO2) revealed a critical observation that these interfaces are reactive even at RT and result in an interfacial compound (˜ 3 nm thick). It is speculated that this reaction layer adversely influences the rectification performance. Thus it is proposed that in addition to choosing the materials based on their work function and electron affinity it is important to consider the thermodynamic stability of these interfaces as well. Band-offsets (electronic barrier height) at metal/insulator interfaces are measured via x-ray photoelectron spectroscopy (XPS). Band-diagrams constructed using the band-offset values agree well with their I-V response, verifying the proposed material design criteria. Measured electronic barrier height values are 0.1 (Nb2O5/Nb), 0 (Nb2O5 /Ti), 0.6 (Nb2O5/Cu) and 0.6 eV (Nb2O 5/Pt).

  8. Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations.

    PubMed

    Kim, Dae-Hyeong; Song, Jizhou; Choi, Won Mook; Kim, Hoon-Sik; Kim, Rak-Hwan; Liu, Zhuangjian; Huang, Yonggang Y; Hwang, Keh-Chih; Zhang, Yong-wei; Rogers, John A

    2008-12-01

    Electronic systems that offer elastic mechanical responses to high-strain deformations are of growing interest because of their ability to enable new biomedical devices and other applications whose requirements are impossible to satisfy with conventional wafer-based technologies or even with those that offer simple bendability. This article introduces materials and mechanical design strategies for classes of electronic circuits that offer extremely high stretchability, enabling them to accommodate even demanding configurations such as corkscrew twists with tight pitch (e.g., 90 degrees in approximately 1 cm) and linear stretching to "rubber-band" levels of strain (e.g., up to approximately 140%). The use of single crystalline silicon nanomaterials for the semiconductor provides performance in stretchable complementary metal-oxide-semiconductor (CMOS) integrated circuits approaching that of conventional devices with comparable feature sizes formed on silicon wafers. Comprehensive theoretical studies of the mechanics reveal the way in which the structural designs enable these extreme mechanical properties without fracturing the intrinsically brittle active materials or even inducing significant changes in their electrical properties. The results, as demonstrated through electrical measurements of arrays of transistors, CMOS inverters, ring oscillators, and differential amplifiers, suggest a valuable route to high-performance stretchable electronics. PMID:19015528

  9. Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations

    PubMed Central

    Kim, Dae-Hyeong; Song, Jizhou; Choi, Won Mook; Kim, Hoon-Sik; Kim, Rak-Hwan; Liu, Zhuangjian; Huang, Yonggang Y.; Hwang, Keh-Chih; Zhang, Yong-wei; Rogers, John A.

    2008-01-01

    Electronic systems that offer elastic mechanical responses to high-strain deformations are of growing interest because of their ability to enable new biomedical devices and other applications whose requirements are impossible to satisfy with conventional wafer-based technologies or even with those that offer simple bendability. This article introduces materials and mechanical design strategies for classes of electronic circuits that offer extremely high stretchability, enabling them to accommodate even demanding configurations such as corkscrew twists with tight pitch (e.g., 90° in ?1 cm) and linear stretching to “rubber-band” levels of strain (e.g., up to ?140%). The use of single crystalline silicon nanomaterials for the semiconductor provides performance in stretchable complementary metal-oxide-semiconductor (CMOS) integrated circuits approaching that of conventional devices with comparable feature sizes formed on silicon wafers. Comprehensive theoretical studies of the mechanics reveal the way in which the structural designs enable these extreme mechanical properties without fracturing the intrinsically brittle active materials or even inducing significant changes in their electrical properties. The results, as demonstrated through electrical measurements of arrays of transistors, CMOS inverters, ring oscillators, and differential amplifiers, suggest a valuable route to high-performance stretchable electronics. PMID:19015528

  10. Fracture mechanics based design for radioactive material transport packagings -- Historical review

    SciTech Connect

    Smith, J.A.; Salzbrenner, D.; Sorenson, K.; McConnell, P.

    1998-04-01

    The use of a fracture mechanics based design for the radioactive material transport (RAM) packagings has been the subject of extensive research for more than a decade. Sandia National Laboratories (SNL) has played an important role in the research and development of the application of this technology. Ductile iron has been internationally accepted as an exemplary material for the demonstration of a fracture mechanics based method of RAM packaging design and therefore is the subject of a large portion of the research discussed in this report. SNL`s extensive research and development program, funded primarily by the U. S. Department of Energy`s Office of Transportation, Energy Management and Analytical Services (EM-76) and in an auxiliary capacity, the office of Civilian Radioactive Waste Management, is summarized in this document along with a summary of the research conducted at other institutions throughout the world. In addition to the research and development work, code and standards development and regulatory positions are also discussed.

  11. Three-dimensional Dirac semimetals: Design principles and predictions of new materials

    NASA Astrophysics Data System (ADS)

    Gibson, Q. D.; Schoop, L. M.; Muechler, L.; Xie, L. S.; Hirschberger, M.; Ong, N. P.; Car, R.; Cava, R. J.

    2015-05-01

    Design principles and predictions of new three-dimensional (3D) Dirac semimetals are presented and placed in the context of currently known materials. Three different design principles are presented (cases I, II, and III), each of which yields predictions for new candidates. For case I, 3D Dirac semimetals based on charge-balanced compounds BaAgBi, SrAgBi, YbAuSb, PtBi2, and SrSn2As2 are identified as candidates. For case II, 3D Dirac semimetals in analogy to graphene, BaGa2 is identified as a candidate, and BaPt and Li2Pt are discussed. For case III, 3D Dirac semimetals based on glide planes and screw axes, TlMo3Te3 and the A Mo3X3 family, in general (A =K , Na, In, Tl; X =Se ,Te), as well as the Group IVb trihalides such as HfI3, are identified as candidates. Finally, we discuss conventional intermetallic compounds with Dirac cones and identify Cr2B as a potentially interesting material.

  12. New and Innovative Educational Material for Teaching Mixed-Domain, Embedded Systems Design to Undergraduate/Graduate Students

    NSDL National Science Digital Library

    Currie, Eddie

    Efforts related to development of innovative, mixed-signal system design, teaching materials and methodology are presented that focus on the co-design of performance-optimized modules for signal sensing, control, actuation, and communication in embedded systems. The methods developed to assess the quality and degree of assimilation by students of the key course concepts are also presented. Cypress Semiconductors PSoCTM mixed-signal architecture was used to illustrate the concepts covered by the developed materials.

  13. An effective evaluation method of material affinity between adjacent material regions of a component for component design

    Microsoft Academic Search

    Xiu-Juan Zhang; Ke-Zhang Chen; Xin-An Feng

    2008-01-01

    Components made of multi-materials become more and more important in high-tech applications. Such a component consists of several different homogeneous and\\/or heterogeneous materials in its different portions to satisfy the critical functional requirements from its applications. Under some working conditions, chemical reactions may be generated and relevant resultants will be produced on the interface between different materials in two adjacent

  14. Design principles and high-pressure syntheses of novel superhard materials

    NASA Astrophysics Data System (ADS)

    Tian, Yongjun

    2014-03-01

    The development of novel high-performance superhard materials, guided by reliable design theories, is highly anticipated for continuous progresses in processing techniques. In the past decade, we have established the hardness model for polar covalent single crystals, and revealed an extra hardening mechanism for polycrystalline materials, which shows a hardness -microstructural size correlation and provides further hardening at deep nanoscale due to quantum confinement effect. Therefore, nanostructuring diamond and cBN is still an effective way to enhance hardness. Based on our model, we estimate the hardness upper limits for diamond and cBN with nanograined and nanotwinned microstructures, respectively. Transformed from graphite-like carbon and BN precursors at high pressure and high temperature (HPHT), nanograined diamond and cBN with the smallest grain size of ~15 nm can be synthesized, showing enhanced hardness but reduced thermal stability. Starting from onion-like BN and carbon, we successfully synthesized nanotwinned cBN and diamond with average twin thickness of 5 nm or below at HPHT. The simultaneous enhancements in hardness, fracture toughness, and thermal stability were confirmed in our nanotwinned cBN and diamond. Our approach offers a general pathway to nano-structure superhard materials for excellent stability and ultrahardness, as well as exceptional tradeoff between hardness and toughness, through the creation of nanotwinned microstructure. This work is supported by NSFC under Grants No. 51332005 and No. 51121061.

  15. Design of a high-temperature experiment for evaluating advanced structural materials

    NASA Technical Reports Server (NTRS)

    Mockler, Theodore T.; Castro-Cedeno, Mario; Gladden, Herbert J.; Kaufman, Albert

    1992-01-01

    This report describes the design of an experiment for evaluating monolithic and composite material specimens in a high-temperature environment and subject to big thermal gradients. The material specimens will be exposed to aerothermal loads that correspond to thermally similar engine operating conditions. Materials evaluated in this study were monolithic nickel alloys and silicon carbide. In addition, composites such as tungsten/copper were evaluated. A facility to provide the test environment has been assembled in the Engine Research Building at the Lewis Research Center. The test section of the facility will permit both regular and Schlieren photography, thermal imaging, and laser Doppler anemometry. The test environment will be products of hydrogen-air combustion at temperatures from about 1200 F to as high as 4000 F. The test chamber pressure will vary up to 60 psia, and the free-stream flow velocity can reach Mach 0.9. The data collected will be used to validate thermal and stress analysis models of the specimen. This process of modeling, testing, and validation is expected to yield enhancements to existing analysis tools and techniques.

  16. Design of a high-temperature experiment for evaluating advanced structural materials

    NASA Astrophysics Data System (ADS)

    Mockler, Theodore T.; Castro-Cedeno, Mario; Gladden, Herbert J.; Kaufman, Albert

    1992-08-01

    This report describes the design of an experiment for evaluating monolithic and composite material specimens in a high-temperature environment and subject to big thermal gradients. The material specimens will be exposed to aerothermal loads that correspond to thermally similar engine operating conditions. Materials evaluated in this study were monolithic nickel alloys and silicon carbide. In addition, composites such as tungsten/copper were evaluated. A facility to provide the test environment has been assembled in the Engine Research Building at the Lewis Research Center. The test section of the facility will permit both regular and Schlieren photography, thermal imaging, and laser Doppler anemometry. The test environment will be products of hydrogen-air combustion at temperatures from about 1200 F to as high as 4000 F. The test chamber pressure will vary up to 60 psia, and the free-stream flow velocity can reach Mach 0.9. The data collected will be used to validate thermal and stress analysis models of the specimen. This process of modeling, testing, and validation is expected to yield enhancements to existing analysis tools and techniques.

  17. Progress on first-principles-based materials design for hydrogen storage.

    PubMed

    Park, Noejung; Choi, Keunsu; Hwang, Jeongwoon; Kim, Dong Wook; Kim, Dong Ok; Ihm, Jisoon

    2012-12-01

    This article briefly summarizes the research activities in the field of hydrogen storage in sorbent materials and reports our recent works and future directions for the design of such materials. Distinct features of sorption-based hydrogen storage methods are described compared with metal hydrides and complex chemical hydrides. We classify the studies of hydrogen sorbent materials in terms of two key technical issues: (i) constructing stable framework structures with high porosity, and (ii) increasing the binding affinity of hydrogen molecules to surfaces beyond the usual van der Waals interaction. The recent development of reticular chemistry is summarized as a means for addressing the first issue. Theoretical studies focus mainly on the second issue and can be grouped into three classes according to the underlying interaction mechanism: electrostatic interactions based on alkaline cations, Kubas interactions with open transition metals, and orbital interactions involving Ca and other nontransitional metals. Hierarchical computational methods to enable the theoretical predictions are explained, from ab initio studies to molecular dynamics simulations using force field parameters. We also discuss the actual delivery amount of stored hydrogen, which depends on the charging and discharging conditions. The usefulness and practical significance of the hydrogen spillover mechanism in increasing the storage capacity are presented as well. PMID:23161910

  18. The occupational endorsement certification in welding and materials technology is designed for beginning students who want to learn to

    E-print Network

    Ickert-Bond, Steffi

    technology is designed for beginning students who want to learn to cut and weld, as well as students seekingWELDING & MATERIALS TECHNOLOGY The occupational endorsement certification in welding and materials and structural metal fabrication. #12;· English · Algebra · Basic Computer Skills · Welding HIGHSCHOOLPREP

  19. A predictive machine learning approach for microstructure optimization and materials design

    PubMed Central

    Liu, Ruoqian; Kumar, Abhishek; Chen, Zhengzhang; Agrawal, Ankit; Sundararaghavan, Veera; Choudhary, Alok

    2015-01-01

    This paper addresses an important materials engineering question: How can one identify the complete space (or as much of it as possible) of microstructures that are theoretically predicted to yield the desired combination of properties demanded by a selected application? We present a problem involving design of magnetoelastic Fe-Ga alloy microstructure for enhanced elastic, plastic and magnetostrictive properties. While theoretical models for computing properties given the microstructure are known for this alloy, inversion of these relationships to obtain microstructures that lead to desired properties is challenging, primarily due to the high dimensionality of microstructure space, multi-objective design requirement and non-uniqueness of solutions. These challenges render traditional search-based optimization methods incompetent in terms of both searching efficiency and result optimality. In this paper, a route to address these challenges using a machine learning methodology is proposed. A systematic framework consisting of random data generation, feature selection and classification algorithms is developed. Experiments with five design problems that involve identification of microstructures that satisfy both linear and nonlinear property constraints show that our framework outperforms traditional optimization methods with the average running time reduced by as much as 80% and with optimality that would not be achieved otherwise. PMID:26100717

  20. Collagen-like peptides and peptide-polymer conjugates in the design of assembled materials

    PubMed Central

    Luo, Tianzhi; Kiick, Kristi L.

    2013-01-01

    Collagen is the most abundant protein in mammals, and there has been long-standing interest in understanding and controlling collagen assembly in the design of new materials. Collagen-like peptides (CLP), also known as collagen-mimetic peptides (CMP) or collagen-related peptides (CRP), have thus been widely used to elucidate collagen triple helix structure as well as to produce higher-order structures that mimic natural collagen fibers. This mini-review provides an overview of recent progress on these topics, in three broad topical areas. The first focuses on reported developments in deciphering the chemical basis for collagen triple helix stabilization, which we review not with the intent of describing the basic structure and biological function of collagen, but to summarize different pathways for designing collagen-like peptides with high thermostability. Various approaches for producing higher-order structures via CLP self-assembly, via various types of intermolecular interaction, are then discussed. Finally, recent developments in a new area, the production of polymer-CLP bioconjugates, are summarized. Biological applications of collagen contained hydrogels are also included in this section. The topics may serve as a guide for the design of collagen-like peptides and their bioconjugates for targeted application in the biomedical arena. PMID:24039275

  1. Thermal and flow analyses of the Nuclear Materials Storage Facility Renovation Title I 60% design

    SciTech Connect

    Knight, T.D.; Steinke, R.G.; Mueller, C.

    1998-08-01

    The authors are continuing to use the computational fluid dynamics code CFX-4.2 to evaluate the steady-state thermal-hydraulic conditions in the Nuclear Material Storage Facility Renovation Title 1 60% Design. The analyses build on those performed for the 30% design. They have run an additional 9 cases to investigate both the performance of the passive vault and of an individual drywell. These cases investigated the effect of wind on the inlet tower, the importance of resolving boundary layers in the analyses, and modifications to the porous-medium approach used in the earlier analyses to represent better the temperature fields resulting from the detailed modeling of the boundary layers. The difference between maximum temperatures of the bulk air inside the vault for the two approaches is small. They continued the analyses of the wind effects around the inflector fixture, a canopy and cruciform device, on the inlet tower by running a case with the wind blowing diagonally across the inflector. The earlier analyses had investigated a wind that was blowing parallel to one set of vanes on the inflector. Several subcases for these analyses investigated coupling the analysis to the facility analysis and design changes for the inflector.

  2. A predictive machine learning approach for microstructure optimization and materials design.

    PubMed

    Liu, Ruoqian; Kumar, Abhishek; Chen, Zhengzhang; Agrawal, Ankit; Sundararaghavan, Veera; Choudhary, Alok

    2015-01-01

    This paper addresses an important materials engineering question: How can one identify the complete space (or as much of it as possible) of microstructures that are theoretically predicted to yield the desired combination of properties demanded by a selected application? We present a problem involving design of magnetoelastic Fe-Ga alloy microstructure for enhanced elastic, plastic and magnetostrictive properties. While theoretical models for computing properties given the microstructure are known for this alloy, inversion of these relationships to obtain microstructures that lead to desired properties is challenging, primarily due to the high dimensionality of microstructure space, multi-objective design requirement and non-uniqueness of solutions. These challenges render traditional search-based optimization methods incompetent in terms of both searching efficiency and result optimality. In this paper, a route to address these challenges using a machine learning methodology is proposed. A systematic framework consisting of random data generation, feature selection and classification algorithms is developed. Experiments with five design problems that involve identification of microstructures that satisfy both linear and nonlinear property constraints show that our framework outperforms traditional optimization methods with the average running time reduced by as much as 80% and with optimality that would not be achieved otherwise. PMID:26100717

  3. Development of a Design Supporting System for Nano-Materials based on a Framework for Integrated Knowledge of Functioning-Manufacturing Process

    E-print Network

    Mizoguchi, Riichiro

    Development of a Design Supporting System for Nano-Materials based on a Framework for Integrated by a computer system. In this article, we aim to develop a conceptual design supporting system for nano-material of the system with some real examples. KEY WORDS ontology, nano-material, design support system 1. Introduction

  4. 75 FR 5708 - Ocean Dumping; Designation of Ocean Dredged Material Disposal Sites Offshore of the Siuslaw River...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-04

    ...too quickly in shallow water. The designation of...material disposal in ocean waters. The proposed Sites...locations within the footprint of each Site and will...Position, Depth of Water, Bottom Topography...designation of the Sites. Transportation of dredges or...

  5. Instructional Design, Cognitive Psychology and the Development of Computer?mediated Learning Materials for Communication Impaired Children

    Microsoft Academic Search

    D. F. Sewell

    1988-01-01

    This paper is concerned with two main themes: (a) an examination of the potential and actual influence of cognitive theory and instructional design, especially in the context of communication?impaired children; (b) a description of a research project, designed in this context, involving the development of ‘interactive’ learning materials for use with severely learning?disabled children.

  6. Effects of material, coating, design and plaque composition on stent deployment inside a stenotic artery--finite element simulation.

    PubMed

    Schiavone, A; Zhao, L G; Abdel-Wahab, A A

    2014-09-01

    Finite-element simulations have been carried out to study the effects of material choice, drug eluting coating and cell design on the mechanical behaviour of stents during deployment inside a stenotic artery. Metallic stents made of materials with lower yield stress and weaker strain hardening tend to experience higher deformation and stronger dogboning and recoiling, but less residual stresses. Drug eluting coatings have limited effect on stent expansion, recoiling, dogboning and residual stresses. Stent expansion is mainly controlled by the radial stiffness of the stent which is closely associated with the stent design. In particular, open-cell design tends to have easier expansion and higher recoiling than closed-cell design. Dogboning is stronger for slotted tube design and open-cell sinusoidal design, but reduced significantly for designs strengthened with longitudinal connective struts. After deployment, the maximum von Mises stress appears to locate at the U-bends of stent cell struts, with varying magnitude that depends on the materials and severity of plastic deformation. For the artery-plaque system, the stresses, especially in the plaque which is in direct contact with the stent, appear to be distinctly different for different stent designs and materials in terms of both distribution and magnitude. The plaque composition also strongly affects the expansion behaviour of the stent-artery system and modifies the stresses on the plaque. PMID:25063145

  7. The Effect of Applying Elements of Instructional Design on Teaching Material for the Subject of Classification of Matter

    ERIC Educational Resources Information Center

    Ozdilek, Zehra; Ozkan, Muhlis

    2009-01-01

    The aim of this study was to examine the effect of instructional materials for the subject of classification of matter as solids, liquids and gases that were developed using a holistic instructional design model on student achievement. In the study a pre-test/post-test with control group experimental design was used. The study was conducted in the…

  8. Band-limited image plane masks for the Terrestrial Planet Finder coronagraph: materials and designs for broadband performance.

    PubMed

    Balasubramanian, Kunjithapatham

    2008-01-10

    Coronagraphs for detection and characterization of exosolar earthlike planets require accurate masks with broadband performance in the visible and near infrared spectrum. Design and fabrication of image plane masks capable of suppressing broadband starlight to 10(-10) level contrast presents technical challenges. We discuss basic approaches, material choices, designs, and fabrication options for image plane masks with particular focus on material properties to obtain adequate spectral performance. Based on theoretical analysis, we show that metals such as Pt and Ni, and alloys such as Inconel, may be employed as promising mask materials that can meet broadband performance requirements. PMID:18188191

  9. Development of Design Standards and Guidelines for Electromagnetic Compatibility and Lightning Protection for Spacecraft Utilizing Composite Materials

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Preliminary design guidelines necessary to assure electromagnetic compatibility (EMC) of spacecraft using composite materials, are presented. A database of electrical properties of composite materials which may have an effect on EMC is established. The guidelines concentrate on the composites that are conductive but may require enhancement to be adequate for EMC purposes. These composites are represented by graphite reinforced polymers. Methods for determining adequate conductivity levels for various EMC purposes are defined, along with the methods of design which increase conductivity of composite materials and joints to adequate levels.

  10. Design and Application of a Beam Testing System for Experiential Learning in Mechanics of Materials

    NSDL National Science Digital Library

    Rais-Rohani, Masoud

    Research shows that students can significantly improve their understanding and retention of topics presented in an engineering course when discussions of theoretical and mathematical approaches are combined with active-learning exercises involving hands-on physical experiments. In this paper, the design and application of a beam testing system (BTS) to promote experiential learning in Mechanics of Materials are discussed. Students in the experimental group were given the opportunity to verify their analytical predictions on two separate projects by conducting experiments using the BTS whereas those in the control group only performed the analysis part. Based on the performance of the two student groups on a common exam problem, the experiential learning is found to have a positive impact. Moreover, the students responses to an anonymous survey indicate that the students in the experimental group generally showed a higher degree of satisfaction with the class projects than those in the control group.

  11. Concurrent Lifetime-Design of Emerging High Temperature Materials and Components

    NASA Astrophysics Data System (ADS)

    Kerans, Ronald J.

    We ask a great deal of structural components used at high temperatures. In addition to performing their primary load bearing function, most of them are subjected to sizable thermal stresses and aggressive atmospheres. Their microstructures and phase compositions, and hence their properties, evolve throughout their lifetime. Many are used in regimes where significant local creep deformation accumulates, so their shapes and residual stress states change also. Finally, many of them are used in situations where failure is extremely undesirable. Failure of a power generation turbine or an aircraft engine carries substantial fiscal costs, and the latter has potential for tragic human costs. The customers — all of us — have very low tolerance for other than extreme reliability. This is a challenging environment in which to introduce new materials. It is an equally challenging environment in which to substitute computation for time-proven testing and design techniques. The penalties for mistakes are extreme and the development costs are correspondingly large.

  12. Design and material variation for an improved power output of AMTEC cells

    NASA Astrophysics Data System (ADS)

    Lodhi, M. A. K.; Daloglu, A.

    A number of design changes for improving the alkali metal thermo-electric converter (AMTEC) cell performance are investigated. In this study, both the material used in AMTEC cell and the dimensions of the cell are changed at the same time. Two different hot side temperatures, Thot=1173 K and Thot=1023 K, are tested. The condenser temperature, Tcond, is kept at 623 K. Results show that the maximum cell conversion efficiency and the maximum electrical power output take place for different cases. Comparing the PX-3A in operation at Thot=1173 K with the one proposed here, the maximum electrical power output and the maximum cell conversion efficiency increased by 43 and 44%, respectively. The corresponding values for Thot=1023 K are 46 and 48%.

  13. Enhanced Diffraction from a Grating on the Surface of a Negative-Index Metamaterial D. R. Smith, P. M. Rye, J. J. Mock, D. C. Vier, and A. F. Starr

    E-print Network

    Nemat-Nasser, Sia

    with negative refractive index (n) have initiated an exploration into the use of these materials to investigate was roughly a factor of 6 smaller than the free space wavelength, so that the material could be expected was thus on the order of =2. The surface stepping on the metamaterial sample con- stitutes a grating, which

  14. Novel biocompatible polymeric blends for bone regeneration: Material and matrix design and development

    NASA Astrophysics Data System (ADS)

    Deng, Meng

    The first part of the work presented in this dissertation is focused on the design and development of novel miscible and biocompatible polyphosphazene-polyester blends as candidate materials for scaffold-based bone tissue engineering applications. Biodegradable polyesters such as poly(lactide-co-glycolide) (PLAGA) are among the most widely used polymeric materials for bone tissue engineering. However, acidic degradation products resulting from the bulk degradation mechanism often lead to catastrophic failure of the structure integrity, and adversely affect biocompatibility both in vitro and in vivo. One promising approach to circumvent these limitations is to blend PLAGA with other macromolecules that can buffer the acidic degradation products with a controlled degradation rate. Biodegradable polyphosphazenes (PPHOS), a new class of biomedical materials, have proved to be superior candidate materials to achieve this objective due to their unique buffering degradation products. A highly practical blending approach was adopted to develop novel biocompatible, miscible blends of these two polymers. In order to achieve this miscibility, a series of amino acid ester, alkoxy, aryloxy, and dipeptide substituted PPHOS were synthesized to promote hydrogen bonding interactions with PLAGA. Five mixed-substituent PPHOS compositions were designed and blended with PLAGA at different weight ratios producing candidate blends via a mutual solvent method. Preliminary characterization identified two specific side groups namely glycylglycine dipeptide and phenylphenoxy that resulted in improved blend miscibility and enhanced in vitro osteocompatibility. These findings led to the synthesis of a mixed-substituent polyphosphazene poly[(glycine ethyl glycinato)1(phenylphenoxy)1phosphazene] (PNGEGPhPh) for blending with PLAGA. Two dipeptide-based blends having weight ratios of PNGEGPhPh to PLAGA namely 25:75 (Matrix1) and 50:50 (Matrix2) were fabricated. Both of the blends were characterized for miscibility, mechanical properties, degradation kinetics, and in vitro osteocompatibility. Primary rat osteoblasts (PRO) isolated from rat calvaria were used to evaluate their in vitro osteocompatibility. The blends were also characterized for in vivo biodegradability and biocompatibility using a rat subcutaneous implantation model. Successful in vivo scaffold-based tissue regeneration greatly depends on the scaffold material biocompatibility, mechanical stability, and scaffold architecture to promote tissue in-growth. The other part of the work in the dissertation is focused on the development of mechanically competent bioresorbable nano-structured three-dimensional (3D) hiomimetic scaffolds for bone tissue engineering applications. Scaffold material selection was based on achieving improved mechanical stability, in vitro osteoblast performance, and in vivo biocompatibility. A miscible PNGEGPhPh-PLAGA blend system developed and characterized in the first part of the thesis work was chosen to fabricate a nanofiber-based mechanically competent biomimetic scaffold via electrospinning. Due to its versatility, controllability and reproducibility, the technique of electrospinning was adopted to produce blend nanofibers. The polymer solution concentration and electrospinning parameters were optimized to produce blend fibers in the range of 50-500 nm to mimic dimensions of collagen fibrils present in the natural extracellular matrix of native bone. These blend nanofiber matrices supported PRO adhesion, proliferation and showed an elevated phenotype expression compared to PLAGA nanofibers. Orienting electrospun nanofibers in a concentric manner with an open central cavity created a mechanically competent 3D scaffold mimicking the bone marrow cavity, as well as, the lamellar structure of bone. The 3D biomimetic scaffold exhibited a similar characteristic mechanical behavior to that of native bone. Compressive modulus of the scaffold was found to be within the range of human trabecular bone. To our knowledge this is the first mechanically competent 3D electrospun n

  15. On the Properties of Materials for Designing Filters at Optical Frequencies

    SciTech Connect

    E. Topsakal; J.L. Volakis

    2003-05-05

    Frequency Selective Surfaces/Volumes (FSS/Vs), periodic structures with frequency selective properties, have widely been used for millimeter and microwave applications. Some applications include filters (band pass, band stop), reflectors, radoms etc. FSS/Vs typically consist of a single or multiple material layers. Multiple layers (with each layer having a different frequency selectivity) are used for broadband applications. In recent years there has been an interest in using these structures at optical wavelengths. One of the applications is in thermophotovoltaic filters used to convert thermal energy into electricity. The filter is designed to transmit those wavelengths that can be efficiently converted into electricity, and to reflect other spectra, which leads to energy conservation and an increase in overall system efficiency. These filters can be used in space missions to help decrease energy consumption and reduce spacecraft mass, cost, and fuel loading. Numerical simulations of such filters are very limited in the literature. Existing modeling approaches are based on the assumption of purely metallic (perfectly conducting) structures on substrates. however, in practice, metals have finite conductivity that can lead to power absorption in the metal. At optical frequencies the usual material properties and perfect electric conductor (PEC) assumption is not applicable. Moreover, the conventional methods, such as using resistive sheets or lossy dielectrics to simulate metallic losses, are not accurate. The goal is to provide a new approach for modeling metallic losses more accurately at the optical frequencies.

  16. Functional design criteria for the Hazardous Materials Management and Emergency Response (HAMMER) Training Center. Revision 1

    SciTech Connect

    Sato, P.K.

    1995-03-10

    Within the United States, there are few hands-on training centers capable of providing integrated technical training within a practical application environment. Currently, there are no training facilities that offer both radioactive and chemical hazardous response training. There are no hands-on training centers that provide training for both hazardous material operations and emergency response that also operate as a partnership between organized labor, state agencies, tribes, and local emergency responders within the US Department of Energy (DOE) complex. Available facilities appear grossly inadequate for training the thousands of people at Hanford, and throughout the Pacific Northwest, who are required to qualify under nationally-mandated requirements. It is estimated that 4,000 workers at the Hanford Site alone need hands-on training. Throughout the Pacific Northwest, the potential target audience would be over 30,000 public sector emergency response personnel, as well as another 10,000 clean-up workers represented by organized labor. The HAMMER Training Center will be an interagency-sponsored training center. It will be designed, built, and operated to ensure that clean-up workers, fire fighters, and public sector management and emergency response personnel are trained to handle accidental spills of hazardous materials. Training will cover wastes at clean-up sites, and in jurisdictions along the transportation corridors, to effectively protect human life, property, and the environment.

  17. Designing materials for advanced microelectronic patterning applications using controlled polymerization RAFT technology

    NASA Astrophysics Data System (ADS)

    Sheehan, Michael T.; Farnham, William B.; Chambers, Charles R.; Tran, Hoang V.; Okazaki, Hiroshi; Brun, Yefim; Romberger, Matthew L.; Sounik, James R.

    2011-04-01

    Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization technology enables the production of polymers possessing low polydispersity (PD) in high yield for many applications. RAFT technology also enables control over polymer architecture. With synthetic control over these polymer characteristics, a variety of polymers can be designed and manufactured for use in advanced electronic applications. By matching the specific RAFT reagent and monomer combinations, we can accommodate monomer reactivity and optimize acrylate or methacrylate polymerizations (193 and 193i photoresist polymers) or optimize styrenic monomer systems (248 nm photoresist polymers) to yield polymers with PD as low as 1.05. For 193i lithography, we have used RAFT technology to produce block copolymers comprising of a random "resist" block with composition and size based on conventional dry photoresist materials and a "low surface energy" block The relative block lengths and compositions may be varied to tune solution migration behavior, surface energy, contact angles, and solubility in developer. Directed self assembly is proving to be an interesting and innovative method to make 2- and even 3-dimensional periodic, uniform patterns. Two keys to acceptable performance of directed self assembly from block copolymers are the uniformity and the purity of the materials will be discussed.

  18. Demonstration of improved vehicle fuel efficiency through innovative tire design, materials, and weight reduction technologies

    SciTech Connect

    Donley, Tim

    2014-12-31

    Cooper completed an investigation into new tire technology using a novel approach to develop and demonstrate a new class of fuel efficient tires using innovative materials technology and tire design concepts. The objective of this work was to develop a new class of fuel efficient tires, focused on the “replacement market” that would improve overall passenger vehicle fuel efficiency by 3% while lowering the overall tire weight by 20%. A further goal of this project was to accomplish the objectives while maintaining the traction and wear performance of the control tire. This program was designed to build on what has already been accomplished in the tire industry for rolling resistance based on the knowledge and general principles developed over the past decades. Cooper’s CS4 (Figure #1) premium broadline tire was chosen as the control tire for this program. For Cooper to achieve the goals of this project, the development of multiple technologies was necessary. Six technologies were chosen that are not currently being used in the tire industry at any significant level, but that showed excellent prospects in preliminary research. This development was divided into two phases. Phase I investigated six different technologies as individual components. Phase II then took a holistic approach by combining all the technologies that showed positive results during phase one development.

  19. Design and Application of The Painting Material Supply System of The Painting Robot for Steel Products

    NASA Astrophysics Data System (ADS)

    Miyawaki, Kunio; Hisayasu, Azuma; Mori, Tsunehito; Miyazaki, Tatsuo; Nakashima, Yoshio

    With the increase of painting works and the decrease of skilled workers, the demand for robot painting of the large-scale steel product is rapidly increasing. But there are many technical problems in the development of the painting robot for this use. The collision between a robot and a work-piece is one of the most important problems, because the robot operates in a small space of a work-piece. Above all, the collision of the painting material supply hose with painted film on a work-piece is very serious. To avoid the hose collision, we propose an in-line type of paint supply mechanism using swivel joints. The key point in this system is the sealing performance and its durability, and we propose the piping system with compliance to strengthen the sealing performance. In this paper, the design method of this system is discussed on the basis of the analysis of the fluctuatinal elastic deformation of a O-ring in the swivel joint. We produced a prototype of the painting robot with the in-line system designed by this method. Application of this robot to the painting of ship-hull block is also discussed. Results from this application show the effectiveness of the in-line system.

  20. Influence of design and material properties on the performance of dielectric elastomer compression sensors

    NASA Astrophysics Data System (ADS)

    Böse, Holger; Fuß, Eric; Lux, Philipp

    2015-04-01

    New designs of dielectric elastomer sensors (DES) which are capable to detect compression loads on rigid as well as on compliant surfaces are introduced in this paper. Currently, DES films exhibit only very poor sensitivity in terms of the change of electric capacitance upon increasing loads for compression measurements. In the new sensor mats, the compression load is converted to a tensile load which acts on an elastomer film located between two profiled elastomer components. In addition, the deformation of the elastomer profiles can also contribute to the sensor effect. All elastomer components were prepared of silicone. A number of parameters which have an influence on the characteristic dependence of capacitance on compression load are discussed. A main influence results from the shape of the elastomer profiles which stretch the elastomer film inside. Also very important are the number and the locations of electrode layers in the sensor mat between which the capacitance is measured. Finally, the hardness of the elastomer plays also a decisive role for the sensor sensitivity. This broad variability of the sensor design offers a high potential to tune the sensor characteristics. Various examples of compression sensors are described and the impact of structural and material parameters is discussed.

  1. WaterTransport in PEM Fuel Cells: Advanced Modeling, Material Selection, Testing and Design Optimization

    SciTech Connect

    J. Vernon Cole; Abhra Roy; Ashok Damle; Hari Dahr; Sanjiv Kumar; Kunal Jain; Ned Djilai

    2012-10-02

    Water management in Proton Exchange Membrane, PEM, Fuel Cells is challenging because of the inherent conflicts between the requirements for efficient low and high power operation. Particularly at low powers, adequate water must be supplied to sufficiently humidify the membrane or protons will not move through it adequately and resistance losses will decrease the cell efficiency. At high power density operation, more water is produced at the cathode than is necessary for membrane hydration. This excess water must be removed effectively or it will accumulate in the Gas Diffusion Layers, GDLs, between the gas channels and catalysts, blocking diffusion paths for reactants to reach the catalysts and potentially flooding the electrode. As power density of the cells is increased, the challenges arising from water management are expected to become more difficult to overcome simply due to the increased rate of liquid water generation relative to fuel cell volume. Thus, effectively addressing water management based issues is a key challenge in successful application of PEMFC systems. In this project, CFDRC and our partners used a combination of experimental characterization, controlled experimental studies of important processes governing how water moves through the fuel cell materials, and detailed models and simulations to improve understanding of water management in operating hydrogen PEM fuel cells. The characterization studies provided key data that is used as inputs to all state-of-the-art models for commercially important GDL materials. Experimental studies and microscopic scale models of how water moves through the GDLs showed that the water follows preferential paths, not branching like a river, as it moves toward the surface of the material. Experimental studies and detailed models of water and airflow in fuel cells channels demonstrated that such models can be used as an effective design tool to reduce operating pressure drop in the channels and the associated costs and weight of blowers and pumps to force air and hydrogen gas through the fuel cell. Promising improvements to materials structure and surface treatments that can potentially aid in managing the distribution and removal of liquid water were developed; and improved steady-state and freeze-thaw performance was demonstrated for a fuel cell stack under the self-humidified operating conditions that are promising for stationary power generation with reduced operating costs.

  2. How to solve materials and design problems in solar heating and cooling. Energy technology review No. 77

    SciTech Connect

    Ward, D.S.; Oberoi, H.S.; Weinstein, S.D.

    1982-01-01

    A broad range of difficulties encountered in active and passive solar space heating systems and active solar space cooling systems is covered. The problems include design errors, installation mistakes, inadequate durability of materials, unacceptable reliability of components, and wide variations in performance and operation of different solar systems. Feedback from designers and manufacturers involved in the solar market is summarized. The designers' experiences with and criticisms of solar components are presented, followed by the manufacturers' replies to the various problems encountered. Information is presented on the performance and operation of solar heating and cooling systems so as to enable future designs to maximize performance and eliminate costly errors. (LEW)

  3. Mirror Material Properties Compiled for Preliminary Design of the Next Generation Space Telescope (30 to 294 Kelvin)

    NASA Technical Reports Server (NTRS)

    Luz, P. L.; Rice, T.

    1998-01-01

    This technical memorandum reports on the mirror material properties that were compiled by NASA Marshall Space Flight Center (MSFC) from April 1996 to June 1997 for preliminary design of the Next Generation Space Telescope (NGST) Study. The NGST study began in February 1996, when the Program Development Directorate at NASA MSFC studied the feasibility of the NGST and developed the pre-phase A program for it. After finishing some initial studies and concepts development work on the NGST, MFSC's Program Development Directorate handed this work to the Observatory Projects Office at MSFC and then to NASA Goddard Space Flight Center (GSFC). This technical memorandum was written by MSFC's Preliminary Design Office and Materials and Processes Laboratory for the NGST Optical Telescope Assembly (OTA) team, in Support of NASA GSFC. It contains material properties for 9 mirror Substrate materials, using information from at least 6 industrial Suppliers, 16 textbooks, 44 technical papers, and 130 technical abstracts.

  4. Design and study of advanced photoresist materials: Positive tone photoresists with reduced environmental impact and materials for 157 nm lithography

    Microsoft Academic Search

    Shintaro Yamada

    2000-01-01

    Concern about using organic solvents in semiconductor manufacturing led us to consider a photoresist system that can be fully processed with aqueous media. A series of new polymers were designed and prepared that demonstrate fully aqueous processable positive tone imaging. Positive tone imaging requires two solubility switches, and this has been accomplished by two different methods. In both cases, a

  5. Designing and preparation of cytisine alkaloid surface-imprinted material and its molecular recognition characteristics

    NASA Astrophysics Data System (ADS)

    Gao, Baojiao; Bi, Concon; Fan, Li

    2015-03-01

    Based on molecular design, a cytisine surface-imprinted material was prepared using the new surface-imprinting technique of "pre-graft polymerizing and post-imprinting". The graft-polymerization of glycidyl methacrylate (GMA) on the surfaces of micron-sized silica gel particles was first performed with a surface-initiating system, preparing the grafted particles PGMA/SiO2. Subsequently, a polymer reaction, the ring-opening reaction of the epoxy groups of the grafted PGMA, was conducted with sodium 2,4-diaminobenzene sulfonate (SAS) as reagent, resulting in the functional grafted particles SAS-PGMA/SiO2. The adsorption of cytisine on SAS-PGMA/SiO2 particles reached saturation via strong electrostatic interaction between the sulfonate groups of SAS-PGMA/SiO2 particles and the protonated N atoms in cytisine molecule. Finally, cytisine surface-imprinting was successfully carried out with glutaraldehyde as crosslinker, obtaining cytisine surface-imprinted material MIP-SASP/SiO2. The binding and recognition characteristics of MIP-SASP/SiO2 towards cytisine were investigated in depth. The experimental results show that there is strong electrostatic interaction between particles and cytisine molecules, and on this basis, cytisine surface-imprinting can be smoothly performed. The surface-imprinted MIP-SASP/SiO2 has special recognition selectivity and excellent binding affinity for cytisine, and the selectivity coefficients of MIP-SASP/SiO2 particles for cytisine relative to matrine and oxymatrine, which were used as two contrast alkaloids, are 9.5 and 6.5, respectively.

  6. A web-based advisory system for process and material selection in concurrent product design for a manufacturing environment

    Microsoft Academic Search

    Xuan F. Zha

    2005-01-01

    This paper reports the work of selecting suitable manufacturing processes and materials in concurrent design for manufacturing environment. In the paper, a fuzzy knowledge-based decision support method is proposed for multi-criteria decision-making in evaluating and selecting possible manufacturing process\\/material combinations in terms of the total production cost. Based on the proposed method, a prototype Web-based knowledge-intensive manufacturing consulting service system

  7. MATERIALS MODELING - A KEY FOR THE DESIGN OF ADVANCED HIGH TEMPERATURE REACTOR COMPONENTS

    Microsoft Academic Search

    Maria Samaras; Wolfgang Hoffelner; Chu-chun Fu; Michel Guttmann; Roger E Stoller

    2007-01-01

    The safe and reliable performance of advanced fission plants is dependent on the choice of suitable materials and assessment of long-term materials degradation. These materials are degraded by their exposure to high temperatures, irradiation and a corrosive environment, therefore it is necessary to address the issue of long term damage evolution of materials under service exposure in advanced plants. A

  8. Design of a piezoelectric-based structural health monitoring system for damage detection in composite materials

    NASA Astrophysics Data System (ADS)

    Kessler, Seth S.; Spearing, S. Mark

    2002-07-01

    Cost-effective and reliable damage detection is critical for the utilization of composite materials. This paper presents the conclusions of an experimental and analytical survey of candidate methods for in-situ damage detection in composite structures. Experimental results are presented for the application of modal analysis and Lamb wave techniques to quasi-isotropic graphite/epoxy test specimens containing representative damage. Piezoelectric patches were used as actuators and sensors for both sets of experiments. Modal analysis methods were reliable for detecting small amounts of global damage in a simple composite structure. By comparison, Lamb wave methods were sensitive to all types of local damage present between the sensor and actuator, provided useful information about damage presence and severity, and present the possibility of estimating damage type and location. Analogous experiments were also performed for more complex built-up structures. These techniques are suitable for structural health monitoring applications since they can be applied with low power conformable sensors and can provide useful information about the state of a structure during operation. Piezoelectric patches could also be used as multipurpose sensors to detect damage by a variety of methods such as modal analysis, Lamb wave, acoustic emission and strain based methods simultaneously, by altering driving frequencies and sampling rates. This paper present guidelines and recommendations drawn from this research to assist in the design of a structural health monitoring system for a vehicle. These systems will be an important component in future designs of air and spacecraft to increase the feasibility of their missions.

  9. Photocatalytic water splitting: Materials design and high-throughput screening of molecular compositions

    NASA Astrophysics Data System (ADS)

    Khnayzer, Rony S.

    Due to the expected increases on energy demand in the near future, the development of new catalytic molecular compositions and materials capable of directly converting water, with the aid of solar photons, into hydrogen becomes obviated. Hydrogen is a combustible fuel and precious high-energy feedstock chemical. However, for the water-splitting reaction to proceed efficiently and economically enough for large-scale application, efficient light-absorbing sensitizers and water splitting catalysts are required. To study the kinetics of the water reduction reaction, we have used titania (TiO2) nanoparticles as a robust scaffold to photochemically grow platinum (Pt) nanoparticles from a unique surface-anchored molecular precursor Pt(dcbpy)Cl2 [dcbpy = 4,4'-dicarboxylic acid-2,2'-bipyridine]. The hybrid Pt/TiO 2 nanomaterials obtained were shown to be a superior water reduction catalyst (WRC) in aqueous suspensions when compared with the benchmark platinized TiO2. In addition, cobalt phosphate (CoPi) water oxidation catalyst (WOC) was photochemically assembled on the surface of TiO2, and its structure and mechanism of activity showed resemblance to the established electrochemically grown CoPi material. Both WRC and WOC described above possessed near unity Faradaic efficiency for hydrogen and oxygen production respectively, and were fully characterized by electron microscopy, x-ray absorption spectroscopy, electrochemistry and photochemistry. While there are established materials and molecules that are able to drive water splitting catalysis, some of these efficient semiconductors, including titanium dioxide (TiO2) and tungsten trioxide (WO3), are only able to absorb high-energy (ultraviolet or blue) photons. This high-energy light represents merely a fraction of the solar spectrum that strikes the earth and the energy content of those remaining photons is simply wasted. A strategy to mitigate this problem has been developed over the years in our laboratory. Briefly, photons of low energy are converted into higher energy light using a process termed photon upconversion. Using this technique, low energy photons supplied by the sun can be converted into light of appropriate energy to trigger electronic transitions in high energy absorbing photoactive materials without any chemical modification of the latter. We have shown, that this technology is capable of upconverting visible sunlight to sensitize wide-bandgap semiconductors such as WO3, subsequently extending the photoaction of these materials to cover a larger portion of the solar spectrum. Besides the engineering of different compositions that serve as either sensitizers or catalysts in these solar energy conversion schemes, we have designed an apparatus for parallel high-throughput screening of these photocatalytic compositions. This combinatorial approach to solar fuels photocatalysis has already led to unprecedented fundamental understanding of the generation of hydrogen gas from pure water. The activity of a series of new Ru(II) sensitizers along with Co(II) molecular WRCs were optimized under visible light excitation utilizing different experimental conditions. The multi-step mechanism of activity of selected compositions was further elucidated by pump-probe transient absorption spectroscopy.

  10. Five types of polyurethane vascular grafts in dogs: the importance of structural design and material selection.

    PubMed

    Xie, Xingyi; Eberhart, Andreas; Guidoin, Robert; Marois, Yves; Douville, Yvan; Zhang, Ze

    2010-01-01

    Five polyurethane vascular grafts with three different chemistries were investigated in terms of device function, healing characteristics and material stability in a canine abdominal aorta model for prescheduled periods of 1 and 6 months. Corvita-reinforced grafts, with walls made of poly(carbonate urethane) (PCU) filaments, displayed a relatively thin, uniform and partially endothelialized inner capsule with good tissue in-growth. The external polyester mesh separated from the underlying PCU wall due to the degradation of the melt adhesive between these two layers. Three types of Thoratec access graft exhibited a high degree of thrombus and little tissue in-growth, and were non-adhesive to both the inner and external capsules as the solid layer beneath their lumens completely blocked any transmural communication. The microporous poly(ether urethane urea) degraded extensively. Pulse-Tec grafts at one month also demonstrated non-adhesive properties because the external skin served as a barrier to tissue in-growth. At 6 months, its poly(ether urethane) wall displayed the most severe degradation, damaging graft structural integrity and causing significant tissue deposition in the degradation areas. This study shows the importance of multiple factors in vascular prosthesis design and demonstrates that collective and comprehensive thinking will be key in the future development of creative and novel approaches. PMID:20507718

  11. Yield Asymmetry Design of Magnesium Alloys by Integrated Computational Materials Engineering

    SciTech Connect

    Li, Dongsheng; Joshi, Vineet V.; Lavender, Curt A.; Khaleel, Mohammad A.; Ahzi, Said

    2013-11-01

    Deformation asymmetry of magnesium alloys is an important factor on machine design in automobile industry. Represented by the ratio of compressive yield stress (CYS) against tensile yield stress (TYS), deformation asymmetry is strongly related to microstructure, characterized by texture and grain size. Modified intermediate phi-model, a polycrystalline viscoplasticity model, is used to predict the deformation behavior of magnesium alloys with different grain sizes. Validated with experimental results, integrated computational materials engineering is applied to find out the route in achieving desired asymmetry by thermomechanical processing. In some texture, for example, rolled texture, CYS/TYS is smaller than 1 under different loading directions. In some texture, for example, extruded texture, asymmetry is large along normal direction. Starting from rolled texture, the asymmetry will increased to close to 1 along rolling direction after compressed to a strain of 0.2. Our model shows that grain refinement increases CYS/TYS. Besides texture control, grain refinement can also optimize the yield asymmetry. After the grain size decreased to a critical value, CYS/TYS reaches to 1 since CYS increases much faster than TYS. By tailoring the microstructure using texture control and grain refinement, it is achievable to optimize yield asymmetry in wrought magnesium alloys.

  12. Role of stem design and material on stress distributions in cemented total hip replacement.

    PubMed

    Christel, P S; Meunier, A; Blanquaert, D; Witvoet, J; Sedel, L

    1988-01-01

    The risk of fatigue fractures of the femoral stem in a cemented total hip arthroplasty can be minimized by either increasing the stem cross-section and/or using a very high strength alloy. The object of this study was to compare important mechanical characteristics of five selected stem designs, differing in configuration and material (stainless steel, cast chrome cobalt alloy, nickel based alloy and titanium alloy). The stain pattern on the stem was analysed in a 3-point-bending jig and also after cementing it into cadaver femurs. Regardless of stem type or test method, the typical tensile stress distribution on the lateral stem was a bell shaped curve. For the cobalt-chrome and stainless steel stems, the larger the stem the lower were the stem stresses and the stress gradient, and the higher was the factor of safety. However, the factor of safety was increased even further by the use of super alloys such as MP35N and Ti6Al4V. In addition, Ti6Al4V alloy allowed the use of larger and stronger stems without the extra penalty of rigidity, which was enforced by either the steel or cobalt based alloy. PMID:3347036

  13. Design and use of nonstandard tensile specimens for irradiated materials testing

    SciTech Connect

    Panayotou, N.F.; Atkin, S.D.; Puigh, R.J.

    1983-08-01

    Two types of miniature specimens been developed to utilize the limited irradiation volume of high energy neutron sources such as the Rotating Target Neutron Source (RTNS)-II and the Fusion Materials Irradiation Test (FMIT) facility. Wire-type specimens have been used to obtain tensile data for several metals irradiated at RTNS-II. Difficulties in the control of wire specimen dimensions led to the design of a miniature tensile specimen which could be fabricated from 0.25 mm thick sheet stock. Sheet-type tensile specimens are currently our standard tensile specimen for high energy neutron source experiments. These specimens are fabricated, like transmission electron microscopy (TEM) disks, by a punching technique. Precise test frame alignment is essential if reproducible test data are to be obtained. The dedicated test frame developed for miniature tensile specimen testing is briefly described. Miniature tensile specimens of a range of metals have been fabricated and tested. The data are reproducible and are in good agreement with data obtained from larger specimens.

  14. Design, synthesis, and characterization of materials for controlled line deposition, environmental remediation, and doping of porous manganese oxide material

    NASA Astrophysics Data System (ADS)

    Calvert, Craig A.

    This thesis covers three topics: (1) coatings formed from sol-gel phases, (2) environmental remediation, and (3) doping of a porous manganese oxide. Synthesis, characterization, and application were investigated for each topic. Line-formations were formed spontaneously by self-assembly from vanadium sol-gels and other metal containing solutions on glass substrates. The solutions were prepared by the dissolution of metal oxide or salt in water. A more straightforward method is proposed than used in previous work. Analyses using optical microscopy, atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and infrared spectroscopy showed discreet lines whose deposition could be controlled by varying the concentration. A mechanism was developed from the observed results. Microwave heating, the addition of graphite rods, and oxidants, can enhance HCB remediation from soil. To achieve remediation, a TeflonRTM vessel open to the atmosphere along with an oxidant, potassium persulfate (PerS) or potassium hydroxide, along with uncoated or aluminum oxide coated, graphite rods were heated in a research grade microwave oven. Microwave heating was used to decrease the heating time, and graphite rods were used to increase the absorption of the microwave energy by providing thermal centers. The results showed that the percent HCB removed was increased by adding graphite rods and oxidants. Tungsten, silver, and sulfur were investigated as doping agents for K--OMS-2. The synthesis of these materials was carried out with a reflux method. The doping of K--OMS-2 led to changes in the properties of a tungsten doped K--OMS-2 had an increased resistivity, the silver doped material showed improved epoxidation of trans-stilbene, and the addition of sulfur produced a paper-like material. Rietveld refinement of the tungsten doped K--OMS-2 showed that the tungsten was doped into the framework.

  15. Corrosion performance of alternative steam-generator materials and designs. Volume 1. Summary of corrosion tests of alternative materials and designs in two model steam generators. Final report

    Microsoft Academic Search

    J. J. Krupowicz; R. M. Rentler

    1983-01-01

    Corrosion results obtained from the post-test non-destructive and destructive examinations of two alternative-materials model steam generators are summarized and compared in this final report. The models operated under representative thermal and hydraulic and accelerated (high contaminant concentration) steam generator secondary water-chemistry conditions. One model was faulted with seawater to a level of 30 ppM chloride for 282 steaming days; the

  16. PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices

    E-print Network

    Sterman, Yoav

    Origami is traditionally implemented in paper, which is a passive material. This research explores the use of material with embedded electronics such as printed circuit boards (PCB) as the medium for origami folding to ...

  17. Stained glass : an investigation into the design potentials of an architectural material

    E-print Network

    Ransom, Shirley Anne

    1986-01-01

    Colored glass is a building material usually associated with churches or days of bygone glory. Yet the material would apparently have much to offer in window openings, curtain walls, even as structural block in the creating ...

  18. Design and fabrication of a modular multi-material 3D printer

    E-print Network

    Lan, Justin (Justin T.)

    2013-01-01

    This thesis presents 3DP-0, a modular, multi-material 3D printer. Currently, 3D printers available on the market are typically expensive and difficult to develop. In addition, the simultaneous use of multiple materials in ...

  19. DESIGN AND DEPLOYMENT OF A MOBILE SENSOR NETWORK FOR THE SURVEILLANCE OF NUCLEAR MATERIALS IN METROPOLITAN AREAS

    E-print Network

    , Latent Models, Cluster Detection, Scan Statistics Abstract--Nuclear attacks are among the most within a certain range of a nuclear source, the radiation energy from the source will trigger the sensorDESIGN AND DEPLOYMENT OF A MOBILE SENSOR NETWORK FOR THE SURVEILLANCE OF NUCLEAR MATERIALS

  20. From the Cover: Materials and noncoplanar mesh designs for integrated circuits with linear elastic responses to extreme mechanical deformations

    Microsoft Academic Search

    Dae-Hyeong Kim; Jizhou Song; Won Mook Choi; Hoon-Sik Kim; Rak-Hwan Kim; Zhuangjian Liu; Yonggang Y. Huang; Keh-Chih Hwang; Yong-Wei Zhang; John A. Rogers

    2008-01-01

    Electronic systems that offer elastic mechanical responses to high-strain deformations are of growing interest because of their ability to enable new biomedical devices and other applications whose requirements are impossible to satisfy with conventional wafer-based technologies or even with those that offer simple bendability. This article introduces materials and mechanical design strategies for classes of electronic circuits that offer extremely

  1. Critical Pedagogic Analysis: An Alternative to User Feedback for (Re)Designing Distance Learning Materials for Language Teachers?

    ERIC Educational Resources Information Center

    Reed, Yvonne

    2012-01-01

    Internationally, guidelines for distance education advise the use of feedback from students in designing and redesigning materials. As my own attempt to elicit such feedback was an instructive failure, I decided to draw on theorisations of pedagogy, mediation and subjectivity and on international and local (South African) conceptualisations of a…

  2. Learning-Goals-Driven Design Model: Developing Curriculum Materials that Align with National Standards and Incorporate Project-Based Pedagogy

    ERIC Educational Resources Information Center

    Krajcik, Joseph; McNeill, Katherine L.; Reiser, Brian J.

    2008-01-01

    Reform efforts in science education emphasize the importance of rigorous treatment of science standards and use of innovative pedagogical approaches to make science more meaningful and successful. In this paper, we present a learning-goals-driven design model for developing curriculum materials, which combines national standards and a…

  3. Using Design of Experiments and Virtual Instrumentation to Evaluate the Tribocharging of Pulverulent Materials in Compressed-Air Devices

    Microsoft Academic Search

    Lucian Dascalescu; Karim Medles; Subhankar Das; Mohamed Younes; Lucian Caliap; Adrian Mihalcioiu

    2008-01-01

    Tribocharging of pulverulent materials in compressed-air devices is a typical multifactorial process. Quantification of the effects of the factors and of their interactions is a prerequisite for the development of new tribocharging devices for industrial applications. This paper aims at demonstrating the interest of using the design of experiments methodology in association with virtual instrumentation for the study of such

  4. Design of self-growing, self-sensing, and self-repairing materials for engineering applications

    Microsoft Academic Search

    Carolyn M. Dry

    2001-01-01

    Like natural biological building systems these materials are inexpensive, and self-form through interaction of the materials. They sense and self-repair, respond to changes in the environment. The volume and scale, cost and end use are all considered from the start. The purpose of the particular system we will describe is an engineered bridge. The materials form as bone does from

  5. Materials data base and design equations for the UCLA solid breeder blanket

    SciTech Connect

    Sharafat, S.; Amodeo, R.; Ghoniem, N.M.

    1986-02-01

    The materials and properties investigated for this blanket study are listed. The phenomenological equations and mathematical fits for all materials and properties considered are given. Efforts to develop a swelling equation based on the few experimental data points available for breeder materials are described. The sintering phenomena for ceramics is investigated.

  6. Material Selection for Optimal Design of Thermally Actuated Pneumatic and Phase Change Microactuators

    Microsoft Academic Search

    Prasanna Srinivasan; S. Mark Spearing

    2009-01-01

    This paper discusses a methodology to select materials which deliver the best performance for thermally actuated pneumatic and phase change microactuators. The material selection is based on performance metrics estimated using simple closed form solutions for classical linear elastic theory for axisymmetric plates\\/membranes and lumped heat capacity thermal models. Although the elastic moduli of the diaphragm materials dictate the volume

  7. Design of multilayer antireflection coatings made from co-sputtered and low-refractive-index materials by genetic algorithm.

    PubMed

    Schubert, Martin F; Mont, Frank W; Chhajed, Sameer; Poxson, David J; Kim, Jong Kyu; Schubert, E Fred

    2008-04-14

    Designs of multilayer antireflection coatings made from co-sputtered and low-refractive-index materials are optimized using a genetic algorithm. Co-sputtered and low-refractive-index materials allow the fine-tuning of refractive index, which is required to achieve optimum anti-reflection characteristics. The algorithm minimizes reflection over a wide range of wavelengths and incident angles, and includes material dispersion. Designs of antireflection coatings for silicon-based image sensors and solar cells, as well as triple-junction GaInP/GaAs/Ge solar cells are presented, and are shown to have significant performance advantages over conventional coatings. Nano-porous low-refractive-index layers are found to comprise generally half of the layers in an optimized antireflection coating, which underscores the importance of nano-porous layers for high-performance broadband and omnidirectional antireflection coatings. PMID:18542630

  8. Unique application of plastics and composite materials in the design of the magnetometer instruments for the Ulysses and Cassini spacecraft

    SciTech Connect

    Noller, E.W. [California Institute of Technology, Pasadena, CA (United States)

    1996-12-31

    The Jet Propulsion Laboratory (JPL) vector helium magnetometer (VHM) design for the Ulysses solar polar mission is the first to explore the structure and characteristics of the magnetic field out of the ecliptic plane. A dual technique combination vector/scalar design that is a modified second generation sensor is currently being manufactured for the Cassini mission. Five major considerations were incorporated into the design: (1) greater use of lightweight composites and plastics, (2) interchangeability of the sensor components, (3) self-alignment of internal optical components, (4) long, projected, stable life of the materials in the deep space environment, and (5) elimination of mechanical fasteners, wherever possible. The nonmagnetic characteristics of plastics and their lightweight-to-strength properties worked together to meet the 900-gram weight limit for the boom-mounted sensor. During the selection process, a wide range of nonmetallic materials were candidates for use in the magnetometer components. The primary materials requirements, beyond environmental and structural, were stringent criteria that all materials and processes for parts be nonmagnetic and free from the thermocouple effect that results when there is the slightest thermal electric noise from the interaction of dissimilar materials. To accomplish this, the manufacturing and assembly had to be free of contamination from particle inclusion in the materials manufacturing, forming, processing, and finishing operations. There was a further requirement that no part of the sensor could have permeable properties in the plastics or adhesives. The dimensional stability of the instruments` optical axis was a critical consideration in the coefficient of thermal expansion (CTE) properties of the materials selected.

  9. Dependence of the mechanical behavior of alloys on their electron work function—An alternative parameter for materials design

    NASA Astrophysics Data System (ADS)

    Lu, Hao; Hua, Guomin; Li, Dongyang

    2013-12-01

    In this article, we demonstrate that the electron work function (EWF) as an intrinsic parameter can provide information or clues in a simple or straightforward way for material design, modification, and development. A higher work function of a material represents a more stable electronic state, which consequently generates a higher resistance to any attempt of changing the electronic state and other corresponding states, e.g., changes in structure or microstructure caused by mechanical and electrochemical actions. Using Cu-Ni alloy as an example, we demonstrate the correlation between the EWF and Young's modulus of the material as well as its hardness. The properties of a material can be modified using elements with appropriate work functions. This is also applicable for tailoring inter-phase boundaries or interfaces.

  10. Design and characterization of nanowire array as thermal interface material for electronics packaging

    E-print Network

    Chiang, Juei-Chun

    2009-05-15

    .................. 11 2.3 Characteristics of Anodic Aluminum Oxide (AAO) ............................ 14 2.4 Thermal Properties of Nanomaterials .................................................. 17 2.5 Proposed TIM Designs... TIM Designs ......................................................................... 22 3.3 Fabrication Process .............................................................................. 25 3.4 Specimen Analysis...

  11. Design and characterization of nanowire array as thermal interface material for electronics packaging 

    E-print Network

    Chiang, Juei-Chun

    2009-05-15

    , because it is non biodegradable, its potential impact on the environment is a concern. In this thesis research, two types of TIMs were designed, synthesized, and characterized. The first type, Designed TIM 1, consisted of anodic aluminum oxide (AAO...

  12. Breckinridge Project, initial effort. Report XI, Volume III. Critical design areas. [Identification of critical design areas; design or materials problems, trade-off areas, items affecting operability and reliability

    SciTech Connect

    none,

    1982-01-01

    Several meetings have been held with representatives from Ashland Synthetic Fuels, Inc.; Airco Energy Company, Inc.; Bechtel Group, Inc.; and HRI Engineering, Inc. to identify critical design areas in the Phase Zero work. (Critical design areas are defined as those requiring additional data or further work to finalize design or material selection, to optimize the trade-off between capital investment and operating cost, or to enhance system operability and reliability.) The critical design areas so identified are summarized by plant in this volume of Report XI. Items of a proprietary nature have been omitted from this report, but are included in the limited access version.

  13. The role of vacancies and local distortions in the design of new phase-change materials

    Microsoft Academic Search

    Matthias Wuttig; Daniel Lüsebrink; Daniel Wamwangi; Wojciech Welnic; Michael Gilleßen; Richard Dronskowski

    2007-01-01

    Phase-change materials are of tremendous technological importance ranging from optical data storage to electronic memories. Despite this interest, many fundamental properties of phase-change materials, such as the role of vacancies, remain poorly understood. `GeSbTe'-based phase-change materials contain vacancy concentrations around 10% in their metastable crystalline structure. By using density-functional theory, the origin of these vacancies has been clarified and we

  14. Design and validation of optimal experiments for estimating thermal properties of composite materials

    Microsoft Academic Search

    Taktak

    1992-01-01

    Composite materials have gained an unprecedented interest in the last twenty years. Their superior strength-to-weight ratios have made them very popular with aerospace, automotive, boat, biomedical, and even the sporting goods industry. The radar-absorbing quality of composite materials, together with their strength-to-weight ratios, make these attractive for military applications. When used in air and space vehicles, composite materials are exposed

  15. Test design description for the Fusion Materials Open Test Assembly (Fusion MOTA-2A): Volume 1A, Part 1

    SciTech Connect

    Bauer, R.E.

    1988-11-01

    This document encompasses the test requirements, hardware design, fabrication, and safety analysis for the Fusion Materials Open Test Assembly experiment for irradiation in FFTF Cycle 11 (Fusion MOTA-2A). Fusion MOTA is equally shared by the US Fusion Material (DOE), Japanese Fusion Materials (MONBUSHO), and BEATRIX-II (IEA) programs. In the interest of providing optimum use of the irradiation space in the Fusion MOTA-2A and LMR MOTA-1G, eight of the Fusion MOTA canisters will be placed in MOTA-1G and an equal number of LMR canisters placed in Fusion MOTA-2A (Powell/Doran 1988). This eliminates the need to process Fusion MOTA-2A through the IEM cell prior to insertion for FFTF Cycle 11A. The LMR MOTA design and safety analysis (Greenslade 1984) is the basis for much of this design and safety analysis report. This design description and safety analysis for the Fusion MOTA-2A is presented per the outline given in Chapter IV of the FTR User`s Guide (Taylor 1978). 35 refs., 17 figs., 9 tabs.

  16. A design strategy for intramolecular singlet fission mediated by charge-transfer states in donor–acceptor organic materials

    NASA Astrophysics Data System (ADS)

    Busby, Erik; Xia, Jianlong; Wu, Qin; Low, Jonathan Z.; Song, Rui; Miller, John R.; Zhu, X.-Y.; Campos, Luis M.; Sfeir, Matthew Y.

    2015-04-01

    The ability to advance our understanding of multiple exciton generation (MEG) in organic materials has been restricted by the limited number of materials capable of singlet fission. A particular challenge is the development of materials that undergo efficient intramolecular fission, such that local order and strong nearest-neighbour coupling is no longer a design constraint. Here we address these challenges by demonstrating that strong intrachain donor–acceptor interactions are a key design feature for organic materials capable of intramolecular singlet fission. By conjugating strong-acceptor and strong-donor building blocks, small molecules and polymers with charge-transfer states that mediate population transfer between singlet excitons and triplet excitons are synthesized. Using transient optical techniques, we show that triplet populations can be generated with yields up to 170%. These guidelines are widely applicable to similar families of polymers and small molecules, and can lead to the development of new fission-capable materials with tunable electronic structure, as well as a deeper fundamental understanding of MEG.

  17. Supramolecular step in design of nonlinear optical materials: Effect of ?...? stacking aggregation on hyperpolarizability.

    PubMed

    Suponitsky, Kyrill Yu; Masunov, Artëm E

    2013-09-01

    Theoretical estimation of nonlinear optical (NLO) properties is an important step in systematic search for optoelectronic materials. Density functional theory methods are often used to predict first molecular hyperpolarizability for compounds in advance of their synthesis. However, design of molecular NLO materials require an estimation of the bulk properties, which are often approximated as additive superposition of molecular tensors. It is therefore important to evaluate the accuracy of this additive approximation and estimate the extent by which intermolecular interactions influence the first molecular hyperpolarizability ?. Here we focused on the stacking aggregates, including up to 12 model molecules (pNA and ANS) and observed enhancement and suppression of molecular hyperpolarizability relative to the additive sum. We found that degree of nonadditivity depends on relative orientation of the molecular dipole moments and does not correlate with intermolecular interaction energy. Frenkel exciton model, based on dipole-dipole approximation can be used for qualitative prediction of intermolecular effects. We report on inaccuracy of this model for the molecules with long ?-systems that are significantly shifted relative to each other, when dipole-dipole approximation becomes inaccurate. To obtain more detailed information on the effect of intermolecular interactions on ? we proposed electrostatic approach which accounts for the mutual polarization of the molecules by each other. We measure the induced polarization of each molecule in the aggregate by the charge of its donor (or acceptor) group. The proposed approach demonstrates linear correlation ?(FF) vs ?(elm) (estimated by finite field theory and electrostatic model, respectively) and allows decomposition of the hyperpolarizability for a molecular aggregate into separate molecular contributions. We used this decomposition to analyze the reasons of deviation of aggregate ? from additivity, as well as the cooperative effect of intermolecular interactions on hyperpolarizability for stacks of growing size. In cases of positive cooperativity (enhancement), we found 6-8 molecules to be necessary to reach the asymptotic limit. In more frequent cases of negative cooperativity two opposite factors play role. The first one consists of direct lowering of ? due to repulsive dipole-dipole interactions. The second factor is originated in a decrease of molecular dipole moments, which in turn leads to a decrease of dipole-dipole repulsion, and therefore increases ?. For strong intermolecular repulsive dipole-dipole interactions these effects nearly cancel each other. In such cases the trimers and even dimers are sufficient to reach the asymptotic limit of the infinite stacks. Based on the observed trends we estimated non-additive correction to ? for well known NLO crystals NPAN and MNMA. In the case of NPAN, stacking effect on molecular hyperpolarizability represents the leading component of the crystal packing effect and improves the agreement between calculated and experimental data which is further improved when frequency dependence is taken in account. PMID:24028120

  18. Supramolecular step in design of nonlinear optical materials: Effect of ?…? stacking aggregation on hyperpolarizability

    NASA Astrophysics Data System (ADS)

    Suponitsky, Kyrill Yu; Masunov, Artëm E.

    2013-09-01

    Theoretical estimation of nonlinear optical (NLO) properties is an important step in systematic search for optoelectronic materials. Density functional theory methods are often used to predict first molecular hyperpolarizability for compounds in advance of their synthesis. However, design of molecular NLO materials require an estimation of the bulk properties, which are often approximated as additive superposition of molecular tensors. It is therefore important to evaluate the accuracy of this additive approximation and estimate the extent by which intermolecular interactions influence the first molecular hyperpolarizability ?. Here we focused on the stacking aggregates, including up to 12 model molecules (pNA and ANS) and observed enhancement and suppression of molecular hyperpolarizability relative to the additive sum. We found that degree of nonadditivity depends on relative orientation of the molecular dipole moments and does not correlate with intermolecular interaction energy. Frenkel exciton model, based on dipole-dipole approximation can be used for qualitative prediction of intermolecular effects. We report on inaccuracy of this model for the molecules with long ?-systems that are significantly shifted relative to each other, when dipole-dipole approximation becomes inaccurate. To obtain more detailed information on the effect of intermolecular interactions on ? we proposed electrostatic approach which accounts for the mutual polarization of the molecules by each other. We measure the induced polarization of each molecule in the aggregate by the charge of its donor (or acceptor) group. The proposed approach demonstrates linear correlation ?FF vs ?elm (estimated by finite field theory and electrostatic model, respectively) and allows decomposition of the hyperpolarizability for a molecular aggregate into separate molecular contributions. We used this decomposition to analyze the reasons of deviation of aggregate ? from additivity, as well as the cooperative effect of intermolecular interactions on hyperpolarizability for stacks of growing size. In cases of positive cooperativity (enhancement), we found 6-8 molecules to be necessary to reach the asymptotic limit. In more frequent cases of negative cooperativity two opposite factors play role. The first one consists of direct lowering of ? due to repulsive dipole-dipole interactions. The second factor is originated in a decrease of molecular dipole moments, which in turn leads to a decrease of dipole-dipole repulsion, and therefore increases ?. For strong intermolecular repulsive dipole-dipole interactions these effects nearly cancel each other. In such cases the trimers and even dimers are sufficient to reach the asymptotic limit of the infinite stacks. Based on the observed trends we estimated non-additive correction to ? for well known NLO crystals NPAN and MNMA. In the case of NPAN, stacking effect on molecular hyperpolarizability represents the leading component of the crystal packing effect and improves the agreement between calculated and experimental data which is further improved when frequency dependence is taken in account.

  19. PROCESS DESIGN AND CONTROL Rigorous Graphical Targeting for Resource Conservation via Material Recycle\\/Reuse Networks

    Microsoft Academic Search

    M. M. El-Halwagi; F. Gabriel; D. Harell

    Material recycle\\/reuse is one of the key strategies in reducing the consumption of fresh resources in the process industries. Over the past decade, several techniques have been developed to reduce the consumption of specific material utilities such as water and hydrogen. To date, none of the published techniques provides a noniterative, systematic, and graphical technique for identifying a target for

  20. Transforming Middle School Geometry: Designing Professional Development Materials that Support the Teaching and Learning of Similarity

    ERIC Educational Resources Information Center

    Seago, Nanette; Jacobs, Jennifer; Driscoll, Mark

    2010-01-01

    Although there are increasing numbers of professional development (PD) materials intended to foster teachers' mathematical knowledge for teaching within the topics of number and algebra, little attention has been given to geometry. In this article we describe the Learning and Teaching Geometry project's approach to the development of PD materials