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1

The Science of Negative Index Materials  

SciTech Connect

Metamaterials are designed to have structures that make available properties not found in Nature. Their unique properties (such as negative index of refraction, n) can be extended from GHz all the way to optical frequencies. We review the scaling properties of metamaterials that have been fabricated and give negative n and negative permeability, {mu}. It is found that most of the experimentally realized metamaterials have {lambda}/{alpha} between 2 (THz and optical region) and 12 (GHz region), where {lambda} is the operation wavelength and {alpha} is the size of the unit cell. The transmission losses for the experimental structures and the ratio {lambda}/{alpha} for the simulated structures are presented. Finally, a comparison of the different metamaterial designs (fishnet, cut and/or continuous wires, and split-ring resonators and wires) is given.

Costas M. Soukoulis; Jiangfeng Zhou; Thomas Koschny; Maria Kafesaki; Eleftherios N. Economou

2008-07-08

2

Simulations of ferrite-dielectric-wire composite negative index materials  

NASA Astrophysics Data System (ADS)

We have performed extensive finite difference time domain (FDTD) simulations to design ferrite based negative index of refraction (NIM) composites. Our simulations center on the use of Barium M type ferrite with in-plane anisotropy. A wire grid is employed to provide negative permittivity. The ferrite and wire grid interact to provide both negative and positive index of refraction transmission peaks in the vicinity of the BaM resonance. We find that the wires and the ferrite must be spatially separated by a low loss dielectric (Mylar). The ferrite and dielectric media are modeled as thin lamina with a mono-directional wire grid centered in the dielectric lamina. The ferrite and dielectric lamina are paired with combined thickness equal to the square wire grid lattice distance. We assume the presence of a in plane orienting magnetic field. Working with thin planar oriented ferrite lamina implies that the composites will have a negative index in only one direction of propagation. Notwithstanding the extreme anisotropy in the index of refraction of the composite, negative refraction is seen at the composite air interface allowing the construction of a focusing concave lens with magnetically tunable focal length.

Rachford, Frederic; Armstead, Douglas; Harris, Vincent; Vittoria, Carmine

2007-03-01

3

A Negative Index Material that Obeys Snell's Law  

Microsoft Academic Search

We measure two-dimensional profiles of collimated microwave beams transmitted through composite wire and split-ring resonator prisms. Prior experiments suggest these structures have a negative index of refraction, though these claims are questioned. Our 2D measurements demonstrate that transmission obeys Snell's Law with a negative index in a narrow frequency regime, confirming the refractive nature of this signal.

Andrew Houck; Jeffrey Brock; Isaac Chuang

2003-01-01

4

Designing a square invisibility cloak using metamaterials made of stacked positive-negative index slabs  

NASA Astrophysics Data System (ADS)

We present a design of a square invisibility cloak based on triangular transformations. In triangular transformations, certain areas of the cloak are squeezed to be infinitesimal in the virtual space. This results in cloak materials whose constitutive parameters are singular. We show rigorously that these prescribed singular materials can be emulated by metamaterials made of stacked positive-negative index slabs. We use numerical simulations to demonstrate the conceived square cloak, which in principle can be constructed using only homogenous and non-singular materials. The proposed square invisibility cloak suggests another important application of negative index media.

Zhu, Guanghao

2013-04-01

5

Design a symmetrical film stack as a negative index metamaterial  

NASA Astrophysics Data System (ADS)

In this work, the equivalent Herpin index and phase thickness of a symmetrical film stack that consists of a dielectric film D and a metal film M are analyzed using the film matrix method. Five-layered symmetrical MDMDM film stacks in which the thickness of each film is less than 1/10 of the incident wavelength are utilized. The positive real part of the equivalent Herpin index and the negative real part of the phase thickness result in a negative real part of the equivalent refractive index. The range of refractive indices of D and M that lead to a negative refractive index of the overall material is developed as a procedure. When a p-polarized light wave obliquely propagates into the material with the negative refractive index, negative refraction and backward wave propagation occur. To reduce the loss in the negative index metamaterial, a porous metal film is introduced as a substitute for the metal film M in MDMDM to increase the feasibility of the use of the metamaterial as an optical coating.

Jen, Yi-Jun; Liu, Wei-Chih; Jheng, Ci-Yao; Yang, Chih-Chieh

2014-08-01

6

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

7

Stability criterion for Gaussian pulse propagation through negative index materials  

SciTech Connect

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.

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

2010-02-15

8

Are negative index materials achievable with surface plasmon waveguides? A case study of  

E-print Network

Are negative index materials achievable with surface plasmon waveguides? A case study of three. Watson Laboratories of Applied Physics, California Institute of Technology, Mail Code 128-95, Pasadena and negative index modes. Particular attention is given to the modes sustained by metal-insulator-metal (MIM

Atwater, Harry

9

Realization of 3D Isotropic Negative Index Materials using Massively Parallel and Manufacturable Microfabrication and Micromachining Technology  

E-print Network

Realization of 3D Isotropic Negative Index Materials using Massively Parallel and Manufacturable Microfabrication and Micromachining Technology Logeeswaran VJ1 , M. Saif Islam1 , Mei Lin Chan2 , David A Horsley2 a method to realize a three dimensional (3D) homogeneous and isotropic negative index materials (3D

Islam, M. Saif

10

Enhancement of correlated photon-pair generation from a positive-negative index material heterostructure  

NASA Astrophysics Data System (ADS)

The generation efficiency of correlated photon pairs from a positive-negative index material heterostructure has been investigated by using a rigorous quantum model of spontaneous parametric down-conversion. The mean number of output photon pairs and the signal-field energy spectrum have been calculated. It is shown that the strong confinements of both the pump and signal fields around the resonance state result in a giant enhancement of the correlated photon-pair generation. The generation rate of the correlated photon pair can be improved by several orders of magnitude in the present structure in comparison with those in the corresponding conventional resonant cavity. This means that the present structure can be applied as a highly efficient potential source for entangled photon pairs.

Wei, Shaozhi; Dong, Yunxia; Wang, Haibo; Zhang, Xiangdong

2010-05-01

11

Negative-Index Metamaterials: Going Optical  

Microsoft Academic Search

The race toward engineering metamaterials comprising of negative refractive indexes in the optical range started with the realization of negative-index materials for gigahertz frequencies six years ago. Sheer miniaturization of the gigahertz resonant structures is one approach. Alternative designs make use of localized plasmon resonant metal nanoparticles or nanoholes in metal films. Following this approach, a negative refractive index has

Thomas A. Klar; Alexander V. Kildishev; Vladimir P. Drachev; Vladimir M. Shalaev

2006-01-01

12

Negative Index of Refraction Portland State University  

E-print Network

, because I thought a negative index of refraction would simply be a reflection, as it would have a negativeNegative Index of Refraction Portland State University PH 464--Dr. Andres LaRosa Joel Rieger March not only showed that these materials have a negative index of refraction, he also showed

La Rosa, Andres H.

13

Optical negative-index metamaterials  

Microsoft Academic Search

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

Vladimir M. Shalaev

2006-01-01

14

Novel microwave devices using tunable negative index metamaterials and ferrites  

Microsoft Academic Search

Next generation microwave devices require to be multifunctional for efficient, cost effective operation in light weight, low volume structures. A miniature tunable negative index metamaterial phase shifter and an ultra wideband phased array antenna have been designed using ferrite materials. Negative permeability ferrite material in combination with negative permittivity of plasmonic wires produces a tunable negative refractive index metamaterial (TNIM).

Patanjali V. Parimi; Peng Peyton; Joseph M. Kunze; Carmine Vittoria; Vincent G. Harris

2009-01-01

15

Negative index metamaterial combining magnetic resonators with metal films  

Microsoft Academic Search

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.

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

2006-01-01

16

Cover Picture: Rapid Research Letter - Focusing slabs made of negative index materials based on inhomogeneous dielectric rods  

NASA Astrophysics Data System (ADS)

In the Rapid Research Letter [1] it is shown that a flat array of dielectric rods can act as a focusing lens of good quality - provided the rods have specified gradients of the dielectric constant. This design is superior to conventional photonic crystals (PC) utilizing homogeneous rods since the lens can be smaller and has better properties in a broader wavelength range.The cover picture is an artist's view of the PC lens made from dielectric rods consisting of three layers with the refractive index increasing from the margin to the center of the rod, focusing a light beam into a small spot. The focusing spot is controlled by the parameters of the rods and their arrangement in the PC slab.The first author, Dr. Vladimir Sergentu, is a senior researcher of the Laboratory of Low Dimensional Semiconductor Structures in Chisinau, Moldova, which works on the design of PC based optical elements in collaboration with the Universities of Kiel and Rochester.

Sergentu, V. V.; Ursaki, V. V.; Tiginyanu, I. M.; Foca, E.; Föll, H.; Boyd, Robert W.

2006-05-01

17

Infrared magnetic and negative-index metamaterials  

Microsoft Academic Search

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 \\

Shuang Zhang

2005-01-01

18

Experimental demonstration of negative index of refraction Jiangfeng Zhou  

E-print Network

Experimental demonstration of negative index of refraction Jiangfeng Zhou Department of Electrical Structure and Laser--FORTH, and Department of Materials Science and Technology, University of Crete, Greece simpler approach in building negative-index materials. Using simulations and microwave experiments, we

19

Experimental demonstration of negative index of refraction Jiangfeng Zhou1  

E-print Network

Experimental demonstration of negative index of refraction Jiangfeng Zhou1 , Thomas Koschny2 Structure and Laser ­ FORTH, and Dept. of Materials Science and Technology, University of Crete, Greece metallic wires that offer a potentially simpler approach in building negative-index materials. Using

20

Robust wedge demonstration to optical negative index metamaterials  

E-print Network

A robust wedge setup is proposed to unambiguously demonstrate negative refraction for negative index metamaterials. We applied our setup to several optical metamaterials from the literature and distinctly observed the phenomena of negative refraction. This further consolidates the reported negative-index property. It is found there generally exists a lateral shift for the outgoing beam through the wedge. We derived a simple expression for calculating this beam shift and interestingly, it provides us a strategy to quantitatively estimate the loss of the wedge material (Im[n]). Addition- ally, we offered a design of metamaterials, compatible with nano-imprinting-lithography, showing negative refractive index in the visible regime (around yellow-light wavelengths). The multi-layer- system retrieval was utilized to extract the effective refractive index of the metamaterial. It was also intuitively characterized through our wedge setup to demonstrate corresponding phenomena of refraction.

Shen, Nian-Hai; Kafesaki, Maria; Soukoulis, Costas M

2014-01-01

21

Robust wedge demonstration to optical negative index metamaterials  

NASA Astrophysics Data System (ADS)

A robust wedge setup is proposed to unambiguously demonstrate negative refraction for negative index metamaterials. We applied our setup to several optical metamaterials from the literature and distinctly observed the phenomena of negative refraction. This further consolidates the reported negative-index property. It is found that there generally exists a lateral shift for the outgoing beam through the wedge. We derived a simple expression for calculating this beam shift and interestingly, it provides us a strategy to quantitatively estimate the loss of the wedge material (Im[n]). Additionally, we offered a design of metamaterials, compatible with nano-imprinting-lithography, showing negative refractive index in the visible regime (around yellow-light wavelengths). The multi-layer-system retrieval was utilized to extract the effective refractive index of the metamaterial. It was also intuitively characterized through our wedge setup to demonstrate corresponding phenomena of refraction.

Shen, Nian-Hai; Koschny, Thomas; Kafesaki, Maria; Soukoulis, Costas M.

2013-06-01

22

Structures with negative index of refraction  

DOEpatents

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

Soukoulis, Costas M. (Ames, IA); Zhou, Jiangfeng (Ames, IA); Koschny, Thomas (Ames, IA); Zhang, Lei (Ames, IA); Tuttle, Gary (Ames, IA)

2011-11-08

23

Loss-free and active optical negative-index metamaterials.  

PubMed

The recently emerged fields of metamaterials and transformation optics promise a family of exciting applications such as invisibility, optical imaging with deeply subwavelength resolution and nanophotonics with the potential for much faster information processing. The possibility of creating optical negative-index metamaterials (NIMs) using nanostructured metal-dielectric composites has triggered intense basic and applied research over the past several years. However, the performance of all NIM applications is significantly limited by the inherent and strong energy dissipation in metals, especially in the near-infrared and visible wavelength ranges. Generally the losses are orders of magnitude too large for the proposed applications, and the reduction of losses with optimized designs seems to be out of reach. One way of addressing this issue is to incorporate gain media into NIM designs. However, whether NIMs with low loss can be achieved has been the subject of theoretical debate. Here we experimentally demonstrate that the incorporation of gain material in the high-local-field areas of a metamaterial makes it possible to fabricate an extremely low-loss and active optical NIM. The original loss-limited negative refractive index and the figure of merit (FOM) of the device have been drastically improved with loss compensation in the visible wavelength range between 722 and 738 nm. In this range, the NIM becomes active such that the sum of the light intensities in transmission and reflection exceeds the intensity of the incident beam. At a wavelength of 737 nm, the negative refractive index improves from -0.66 to -1.017 and the FOM increases from 1 to 26. At 738 nm, the FOM is expected to become macroscopically large, of the order of 10(6). This study demonstrates the possibility of fabricating an optical negative-index metamaterial that is not limited by the inherent loss in its metal constituent. PMID:20686570

Xiao, Shumin; Drachev, Vladimir P; Kildishev, Alexander V; Ni, Xingjie; Chettiar, Uday K; Yuan, Hsiao-Kuan; Shalaev, Vladimir M

2010-08-01

24

Radiation Pressure and Photon Momentum in Negative-Index Media  

E-print Network

Radiation pressure and photon momentum in negative-index media are no different than their counterparts in ordinary (positive-index) materials. This is because the parameters responsible for these properties are the admittance, sqrt(epsilon/mu), and the group refractive index n_g of the material (both positive entities), and not the phase refractive index, n=sqrt(epsilon*mu), which is negative in negative-index media. One approach to investigating the exchange of momentum between electromagnetic waves and material media is via the Doppler shift phenomenon. In this paper we use the Doppler shift to arrive at an expression for the radiation pressure on a mirror submerged in a negative-index medium. In preparation for the analysis, we investigate the phenomenon of Doppler shift in various settings, and show the conditions under which a so-called "inverse" Doppler shift could occur. We also argue that a recent observation of the inverse Doppler shift upon reflection from a negative-index medium cannot be correct,...

Mansuripur, Masud

2013-01-01

25

From Scattering Parameters to Snell's Law: A Subwavelength Near-Infrared Negative-Index Metamaterial  

Microsoft Academic Search

A general relation is derived between the band structure of an arbitrary low-loss unit cell and its effective index of refraction. In addition, we determine the maximum unit cell size that defines the ``metamaterial regime'' [D. R. Smith , Phys. Rev. E 71, 036617 (2005)PLEEE81063-651X10.1103\\/PhysRevE.71.036617]. Furthermore, these general rules allow for the design of a subwavelength near-infrared negative-index material, where

Xuhuai Zhang; Marcelo Davanço; Yaroslav Urzhumov; Gennady Shvets; Stephen R. Forrest

2008-01-01

26

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

Microsoft Academic Search

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

Jason Valentine; Shuang Zhang; Thomas Zentgraf; Xiang Zhang

2011-01-01

27

Mirrorless Negative-index Parametric Microoscillator  

Microsoft Academic Search

The feasibility and extraordinary properties of mirrorless parametric\\u000aoscillations in strongly absorbing negative-index metamaterials are shown. They\\u000astem from the backwardness of electromagnetic waves inherent to this type of\\u000ametamaterials.

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

2008-01-01

28

Nanoimprinting techniques for large-area three-dimensional negative index metamaterials with operation in the visible and telecom bands.  

PubMed

We report advances in materials, designs, and fabrication schemes for large-area negative index metamaterials (NIMs) in multilayer "fishnet" layouts that offer negative index behavior at wavelengths into the visible regime. A simple nanoimprinting scheme capable of implementation using standard, widely available tools followed by a subtractive, physical liftoff step provides an enabling route for the fabrication. Computational analysis of reflection and transmission measurements suggests that the resulting structures offer negative index of refraction that spans both the visible wavelength range (529-720 nm) and the telecommunication band (1.35-1.6 ?m). The data reveal that these large (>75 cm(2)) imprinted NIMs have predictable behaviors, good spatial uniformity in properties, and figures of merit as high as 4.3 in the visible range. PMID:24730614

Gao, Li; Shigeta, Kazuki; Vazquez-Guardado, Abraham; Progler, Christopher J; Bogart, Gregory R; Rogers, John A; Chanda, Debashis

2014-06-24

29

Low-loss negative-index metamaterial at telecommunication wavelengths  

Microsoft Academic Search

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

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

2006-01-01

30

Entanglement creation with negative index metamaterials  

E-print Network

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.

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

2012-05-21

31

Large-Area Flexible 3D Optical Negative Index Metamaterial Formed by Nanotransfer Printing.  

National Technical Information Service (NTIS)

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...

A. Carlson, D. Chanda, K. Shigeta, S. Gupta, T. Cain

2011-01-01

32

Mechanically Tunable Negative-Index Photonic Crystal Lens  

E-print Network

Mechanically Tunable Negative-Index Photonic Crystal Lens Volume 2, Number 6, December 2010 Y. Cui;Mechanically Tunable Negative-Index Photonic Crystal Lens Y. Cui,1;2 V. A. Tamma,1 J.-B. Lee,2 and W. Park1 1 systems (MEMS)-enabled mechanically tunable negative-index photonic crystal lens, which was comprised of 2

Lee, Jeong-Bong

33

Experimental Verification and Simulation of Negative Index of Refraction Using Snell's Law  

Microsoft Academic Search

We report the results of a Snell's law experiment on a negative index of refraction material in free space from 12.6 to 13.2GHz. 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 12.6GHz we measure and compute

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

2003-01-01

34

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

PubMed

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

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

2010-05-01

35

Optical negative-index bulk metamaterials con-sisting of 2D perforated metal-dielectric stacks  

E-print Network

Optical negative-index bulk metamaterials con- sisting of 2D perforated metal-dielectric stacks for High Technology Materials and Department of Electrical and Computer Engineering, University of New-infrared negative-index metama- terial (NIM) slab consisting of multiple layers of perforated metal

New Mexico, University of

36

Microscopic mirrorless negative-index optical parametric oscillator  

E-print Network

the backwardness of electromagnetic waves inherent with this type of metamaterial. © 2009 Optical Society oscillations in a microscopic strongly absorbing slab of negative-index metamaterial are shown. They stem from of America OCIS codes: 190.4975, 190.4970, 160.4236, 270.1670. Optical negative-index (NI) metamaterials

Shalaev, Vladimir M.

37

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

E-print Network

that a material with a negative index of refraction can be used to construct a perfect lens [1], a quest for media at an inter- face of a positive index medium with the metamaterial. Indefinite materials form another class and the conversion of incident evanescent waves to propagating waves [8­11]. However, negatively refracting

Polman, Albert

38

Strongly birefringent cut-wire pair structure as negative index wave plates at THz frequencies  

E-print Network

We report a new approach for the design and fabrication of thin wave plates with high transmission in the terahertz (THz) regime. The wave plates are based on strongly birefringent cut-wire pair metamaterials that exhibit refractive indices of opposite signs for two orthogonal polarization components of an incident wave. As specific examples, we fabricated and investigated a quarter- and a half-wave plate that revealed a peak intensity transmittance of 74% and 58% at 1.34 THz and 1.3 THz, respectively. Furthermore, the half wave plate displayed a maximum figure of merit (FOM) of 23 at 1.3 THz where the refractive index was -1.7. This corresponds to one of the highest FOMs reported at THz frequencies so far. The presented results evidence that negative index materials enter an application stage in terms of optical components for the THz technology.

Weis, P; Imhof, C; Beigang, R; Rahm, M

2009-01-01

39

Mirrorless Negative-index Parametric Micro-oscillator  

E-print Network

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.

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

2008-07-22

40

Mirrorless Negative-index Parametric Micro-oscillator  

E-print Network

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.

Popov, Alexander K; Shalaev, Vladimir M

2008-01-01

41

Microscopic mirrorless negative-index optical parametric oscillator  

Microsoft Academic Search

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.

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

2009-01-01

42

Microscopic mirrorless negative-index optical parametric oscillator  

Microsoft Academic Search

The feasibility and extraordinary properties of mirrorless optical parametric oscillations in a microscopic strongly absorbing slab of negative-index metamaterial are shown. They stem from the backwardness of electromagnetic waves inherent with this type of metamaterial.

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

2009-01-01

43

Active negative-index metamaterial powered by an electron beam  

E-print Network

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 ...

Shapiro, Michael

44

Sub-picosecond optical switching with a negative index metamaterial  

SciTech Connect

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

Dani, Keshav M [Los Alamos National Laboratory; Upadhya, Prashant C [Los Alamos National Laboratory; Zahyum, Ku [CHTM-UNM

2009-01-01

45

Symmetry breaking and optical negative index of closed nanorings.  

PubMed

Metamaterials have extraordinary abilities, such as imaging beyond the diffraction limit and invisibility. Many metamaterials are based on split-ring structures, however, like atomic orbital currents, it has long been believed that closed rings cannot produce negative refractive index. Here we report a low-loss and polarization-independent negative-index metamaterial made solely of closed metallic nanorings. Using symmetry breaking that negatively couples the discrete nanorings, we measured negative phase delay in our composite 'chess metamaterial'. The formation of an ultra-broad Fano-resonance-induced optical negative-index band, spanning wavelengths from 1.3 to 2.3??m, is experimentally observed in this structure. This discrete and mono-particle negative-index approach opens exciting avenues towards symmetry-controlled topological nanophotonics with on-demand linear and nonlinear responses. PMID:23149726

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

2012-01-01

46

Symmetry breaking and optical negative index of closed nanorings  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

47

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

NASA Astrophysics Data System (ADS)

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

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

48

Discontinuous design of negative index metamaterials based on mode hybridization  

E-print Network

in mirrored single-gap asymmetric split ring resonator terahertz metamaterials Appl. Phys. Lett. 101, 071108 for Surface and Nanoanalytics, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria 3 and magnetic resonances of the same plasmon mode to realize a spectral region, in which permittivity and perme

49

All-semiconductor negative-index plasmonic absorbers.  

PubMed

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

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

2014-01-10

50

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

SciTech Connect

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

Guney, Durdu; Koschny, Thomas; Soukoulis, Costas

2010-05-26

51

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

PubMed

Isotropic negative index metamaterials (NIMs) are highly desired, particularly for the realization of ultra-high resolution lenses. However, existing isotropic NIMs function only two-dimensionally and cannot be miniaturized beyond microwaves. Direct laser writing processes can be a paradigm shift toward the fabrication of three-dimensionally (3D) isotropic bulk optical metamaterials, but only at the expense of an additional design constraint, namely connectivity. Here, we demonstrate with a proof-of-principle design that the requirement connectivity does not preclude fully isotropic left-handed behavior. This is an important step towards the realization of bulk 3D isotropic NIMs at optical wavelengths. PMID:20588360

Güney, Durdu O; Koschny, Thomas; Soukoulis, Costas M

2010-06-01

52

Realization of negative index in second-order dispersive metamaterials using standard dispersion models for electromagnetic parameters  

NASA Astrophysics Data System (ADS)

In recent work, electromagnetic propagation velocities for plane waves in dispersive metamaterials were calculated assuming frequency dispersion up to the second order. The three velocities were expressed in terms of dispersive coefficients under certain simplifying constraints. Frequency domains were found to exist around resonances where group and phase velocities are in opposition, implying possible negative index behavior. In this paper, we incorporate in the derived equations physical models (including Debye, Lorentz and Condon) for material dispersion in permittivity, permeability and chirality in order to further examine the consequences of second-order dispersion leading to negative index for practical cases, and also evaluate the resulting phase and group indices.

Algadey, Tarig A.; Chatterjee, Monish R.

2014-09-01

53

Theory of fishnet negative-index optical metamaterials  

E-print Network

We theoretically study fishnet metamaterials at optical frequencies. In contrast to earlier works, we provide a microscopic description by tracking the transversal and longitudinal flows of energy through the fishnet mesh composed of intersecting subwavelength plasmonic waveguides. The analysis is supported by a semi-analytical model based on surface-plasmon coupled-mode equations, which provides accurate formulas for the fishnet refractive index, including the real-negative and imaginary parts. The model simply explains how the surface plasmons couple at the waveguide intersections and it shines new light on the fishnet negative-index paradigm at optical frequencies. Extension of the theory for loss-compensated metamaterials with gain media is also presented.

Yang, J; Liu, H T; Lalanne, P

2011-01-01

54

Theory of fishnet negative-index optical metamaterials.  

PubMed

We theoretically study fishnet metamaterials at optical frequencies. In contrast with earlier works, we provide a microscopic description by tracking the transversal and longitudinal flows of energy through the fishnet mesh composed of intersecting subwavelength plasmonic waveguides. The analysis is supported by a semianalytical model based on surface-plasmon coupled-mode equations, which provides accurate formulas for the fishnet refractive index, including the real-negative and imaginary parts. The model simply explains how the surface plasmons couple at the waveguide intersections, and it shines new light on the fishnet negative-index paradigm at optical frequencies. Extension of the theory for loss-compensated metamaterials with gain media is also presented. PMID:21867008

Yang, J; Sauvan, C; Liu, H T; Lalanne, P

2011-07-22

55

Large Area 3D Negative Index Metamaterials Formed by Printing  

NASA Astrophysics Data System (ADS)

Negative index metamaterials (NIMS) are man-made structures with values of permittivity and permeability that are simultaneously negative over some range of frequencies. Although advanced lithographic techniques can form the necessary three dimensional (3D) nanoscale features for NIMS, such methods can be applied only over small areas (100's of ?m^2) on specialized substrates, with low throughput. This talk summarizes a 3D transfer printing method that can yield 3D-NIMs with excellent optical characteristics, in ways that are scalable to arbitrarily large areas and are compatible with manufacturing. We demonstrate 3D-NIMs with 11-layers and sub-micron unit cell dimensions, over areas > 75 cm^2, corresponding to >10^5x10^5 unit cells, all with excellent uniformity and minimal defects. These areas and numbers of unit cells both correspond to increases of more than 2x10^7 times, over previous results. Multiple cycles of printing with a single stamp demonstrate use in a manufacturing mode at throughputs that are ˜10^8 times higher than those possible with state-of-the-art focused-ion beam lithography systems (˜2.5 s per unit cell). Optical measurements show negative index of refraction in the NIR spectral range, with values as large as Re(n) ˜ -7 at ? = 2.4 ?m and high figures of merit (FOM) of ˜8 at ? = 1.95 ?m indicating low loss operation Related approaches can be used to form similar classes of 3D-NIMS with operation in the visible regime.

Rogers, John

2012-02-01

56

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

E-print Network

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

Sridhar, Srinivas

57

Resonant nonlinear optics of backward waves in negative-index metamaterials  

E-print Network

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.

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

2008-08-14

58

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

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

59

Creating wide-band negative-index-of-refraction metamaterials with fractal-based geometry  

NASA Astrophysics Data System (ADS)

A burgeoning topic of modern research in electrodynamics and antenna design is the design and fabrication of ``left-handed'' metamaterials. This ``left-handedness'' is often created through use of an array of conductive structures with geometry appropriate for coupling on the wavelength scale with incident radiation to produce a phase-shifted reflected wave that cancels out incoming radiation and prevents transmission. This property has been demonstrated in several papers published in the last decade. In every instance, though the ``left-handed'' response is only exhibited in a small bandwidth centered about a specific frequency (bandwidth typically less that 0.1 GHz). I will show that through use of tessellated, fractal-based structures, one can create a repeatable geometry that exhibits a negative index of refraction (NIR) for multiple frequency bands, limited only by fabrication precision, with the ultimate goal being a wide-band absorptive response.

Penney, Keith

2009-11-01

60

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

SciTech Connect

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

Bello, F. [Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain)

2011-07-15

61

Broadband optical resonator based on coupled positive- and negative-index waveguides  

NASA Astrophysics Data System (ADS)

We propose and design a broadband optical resonator fashioned from two types of waveguides: one sustaining a positive-index mode with a positive phase velocity and another sustaining a negative-index mode with a negative phase velocity. The former has a wavelength that decreases as a function of frequency, while the latter has a wavelength that increases as a function of frequency. Because frequency-dependent wavelength increases in one waveguide component of the resonator are compensated by wavelength decreases in the other component, the resonator can potentially support a continuum of standing wave patterns that all satisfy the same resonance condition, effectively widening the frequency range over which resonance is achievable. We have tailored the geometry of the resonator so that the net phase accrued within the resonator is nearly constant over a large portion of the visible frequency range, and, as shown through FDTD simulations and analytical calculations, a broadband optical resonance is achieved.

Bethune-Waddell, Max; Chau, Kenneth J.

2012-03-01

62

Experimental Verification of a Negative Index of Refraction  

Microsoft Academic Search

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

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

2001-01-01

63

Materials in design  

E-print Network

with machine tools. ~ytdb'1't ? b'lty 1 lit b 1 dt 111 different material by welding. Work hardenabilit ? property of a material to increase in hardness as it is mechanically worked. There are other properties such as color, odor, acoustical properties... processes that yield many design possibilities not economically obtainable by other production methods, Processes such as casting, powder metallurgy extrusion, welding, etc. must be studied by the engineer in order to select the best process to obtain...

Perata, Alfredo Ferando

2012-06-07

64

Subpicosecond Optical Switching with a Negative Index Metamaterial  

E-print Network

optical noise and require significant additional area for carrier injection and heat dissipation.1 High been devoted to the fabrication of these materials, the characterization of their linear optical and dynamically affect the resonance behav- ior. With 60 fs pulses and 3 nJ of pump pulse energy absorbed across

New Mexico, University of

65

Nonplanar chiral metamaterials with negative index Bingnan Wang,1  

E-print Network

. Similar to metamaterials designed for linear polarized waves, CMs are also periodic arrangements of the electromagnetic EM waves in chiral media are the right-handed circularly polarized RCP + wave and the left, the RCP and LCP waves interact with the chiral particles differently and are absorbed to a different

66

Synthesis of Low-Loss Metamaterials with Negative Index in the Visible Domain  

NASA Astrophysics Data System (ADS)

Over the last decade, negative index media have attracted much attention due to their potential applications, especially the possibility of constructing superlenses. However, achieving high-performance negative-index metamaterials at visible frequencies, where this kind of media could find many applications, still remains a challenge. In this article, we provide a brief overview of the main routes for the implementation of metamaterials with negative index in this band, with a special focus on the so-called fishnet metamaterial. We pay particular attention to a specific fishnet configuration that recently allowed for the experimental demonstration of a low-loss and polarization-insensitive negative-index band in the visible regime.

García-Meca, Carlos

2013-06-01

67

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

Microsoft Academic Search

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

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

2006-01-01

68

Strongly birefringent metamaterials as negative index terahertz wave plates  

NASA Astrophysics Data System (ADS)

We report an alternative approach for the design and fabrication of thin wave plates with high transmission in the terahertz regime. The wave plates are based on strongly birefringent cut-wire-pair metamaterials that exhibit refractive indices of opposite signs for orthogonal polarization components of an incident wave. As examples, we fabricated and investigated a quarter- and a half-wave plate with high intensity transmittance. The wave plates displayed a maximum figure of merit (FOM) of 23 at a frequency around 1.3 THz where the refractive index was n'=-1.7. This corresponds to one of the highest FOMs reported at terahertz frequencies.

Weis, P.; Paul, O.; Imhof, C.; Beigang, R.; Rahm, M.

2009-10-01

69

Compensating losses in negative-index metamaterials by optical parametric amplification  

E-print Network

with no cavity in strongly absorbing negative-index metamaterials. The opposite directions of the wave vector), also referred to as left-handed metamateri- als (LHMs), exhibit highly unusual electromagnetic- edented linear and nonlinear electromagnetic proper- ties. The opposite directions of the wave and Poyn

Shalaev, Vladimir M.

70

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

E-print Network

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.

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

2007-08-01

71

Negative index short-slab pair and continuous wires metamaterials in the far infrared regime  

E-print Network

transmission and reflection measurements under normal incidence in one and three layers of a m procedure, we demonstrate the occurrence of a negative refractive index regime in the far infrared range, ~2. Smith, and S. Schultz, "Experimental verification of a negative index of refraction," Science 292, 77

72

SHORT PROGRAMS Materials By Design  

E-print Network

SHORT PROGRAMS Materials By Design Overview The demand for high-performance materials with superior domains such as biomaterials and implants, adhesives, construction materials, and structural materials L O G Y About MIT Professional Education Short Programs: Approximately 40 courses are taught

Entekhabi, Dara

73

Material-based design computation  

E-print Network

The institutionalized separation between form, structure and material, deeply embedded in modernist design theory, paralleled by a methodological partitioning between modeling, analysis and fabrication, resulted in ...

Oxman, Neri

2010-01-01

74

Design Strategies for Educational Materials.  

ERIC Educational Resources Information Center

This manual, which is part of a series of training and information materials for managers and trainers of health staff in developing countries, is designed to assist individuals responsible for designing national health learning materials. The introduction explains the manual's purpose, organization, and use and discusses the importance of…

Fournier, Deborah; And Others

75

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

E-print Network

dispersion. Since super-lensing depends on the matching between the positive and negative index media 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

76

Microstructural design in cellular materials  

SciTech Connect

In last year's continuation proposal the work outlined for the period January 1991--January 1992 was focused on microstructural design of cellular materials; specifically we suggested honeycomb-like microstructures and composite foams with sandwich cell walls. We also planned to examine natural cellular materials to see if their structure suggests ways in which engineering cellular materials might be improved. We planned to make cellular materials with several different microstructures; to characterize their microstructure; and to measure their mechanical properties.

Gibson, L.J.

1992-01-31

77

Negative Index of Refraction Observed in a Single Layer of ClosedRing Magnetic Dipole Resonators  

SciTech Connect

We report the results of a spectroscopic study of a singlelayer of metallic single closed ring resonators on free-standing thinmembrane at near-normal and grazing angles of incidence. When themagnetic component of the light is perpendicular to the ring plane, weobserve a negative index of refraction down to -1 around 150 terahertz(THz), attributed to a strong magnetic dipolar resonance and a broadelectric resonance in this metamaterial. We experimentally identify thedifferent resonance modes and the spectral region of negative refractiveindex on a series of samples with different feature and lattice sizes,comparing to electromagnetic simulations.

Hao, Zhao; Martin, Michael C.; Harteneck, Bruce; Cabrini,Stefano; Anderson, Erik H.

2007-11-27

78

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

E-print Network

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.

A. K. Popov; Vladimir M. Shalaev

2006-01-10

79

Measurement of a Broadband Negative Index with Space-Coiling Acoustic Metamaterials  

NASA Astrophysics Data System (ADS)

We report the experimental demonstration of a broadband negative refractive index obtained in a labyrinthine acoustic metamaterial structure. Two different approaches were employed to prove the metamaterial negative index nature: one-dimensional extractions of effective parameters from reflection and transmission measurements and two-dimensional prism-based measurements that convincingly show the transmission angle corresponding to negative refraction. The transmission angles observed in the latter case also agree very well with the refractive index obtained in the one-dimensional measurements and numerical simulations. We expect this labyrinthine metamaterial to become the unit cell of choice for practical acoustic metamaterial devices that require broadband and significantly negative indices of refraction.

Xie, Yangbo; Popa, Bogdan-Ioan; Zigoneanu, Lucian; Cummer, Steven A.

2013-04-01

80

Deep-subwavelength negative-index waveguiding enabled by coupled conformal surface plasmons.  

PubMed

In this Letter we introduce a novel route for achieving negative-group-velocity waveguiding at deep-subwavelength scales. Our scheme is based on the strong electromagnetic coupling between two conformal surface plasmon structures. Using symmetry arguments and detailed numerical simulations, we show that the coupled system can be geometrically tailored to yield negative-index dispersion. A high degree of subwavelength modal confinement, of ?/10 in the transversal dimensions, is also demonstrated. These results can assist in the development of ultrathin surface circuitry for the low-frequency region (microwave and terahertz regimes) of the electromagnetic spectrum. PMID:24978255

Quesada, R; Martín-Cano, D; García-Vidal, F J; Bravo-Abad, J

2014-05-15

81

Measurement of a broadband negative index with space-coiling acoustic metamaterials.  

PubMed

We report the experimental demonstration of a broadband negative refractive index obtained in a labyrinthine acoustic metamaterial structure. Two different approaches were employed to prove the metamaterial negative index nature: one-dimensional extractions of effective parameters from reflection and transmission measurements and two-dimensional prism-based measurements that convincingly show the transmission angle corresponding to negative refraction. The transmission angles observed in the latter case also agree very well with the refractive index obtained in the one-dimensional measurements and numerical simulations. We expect this labyrinthine metamaterial to become the unit cell of choice for practical acoustic metamaterial devices that require broadband and significantly negative indices of refraction. PMID:23679743

Xie, Yangbo; Popa, Bogdan-Ioan; Zigoneanu, Lucian; Cummer, Steven A

2013-04-26

82

Refraction of electromagnetic energy for wave packets incident on a negative-index medium is always negative  

E-print Network

Refraction of electromagnetic energy for wave packets incident on a negative-index medium is always February 2004 We analyze refraction of electromagnetic wave packets on passing from an isotropic positive, since all physical sources of electromagnetic waves produce radiation fields of finite spatial

Sridhar, Srinivas

83

Material and processes selection in conceptual design  

E-print Network

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...

Krishnakumar, Karthikeyan

2005-02-17

84

Computational methodologies for designing materials  

Microsoft Academic Search

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

Talat S Rahman

2009-01-01

85

Translating materials design to the clinic  

NASA Astrophysics Data System (ADS)

Many materials-based therapeutic systems have reached the clinic or are in clinical trials. Here we describe materials design principles and the construction of delivery vehicles, as well as their adaptation and evaluation for human use.

Hubbell, Jeffrey A.; Langer, Robert

2013-11-01

86

Managing Training Materials with Structured Text Design.  

ERIC Educational Resources Information Center

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

Streit, Les D.; And Others

1986-01-01

87

Realization Robust Materials Design of  

E-print Network

metal sandwich panel with a square honeycomb core · Design objective: minimize deflection of the back of Clamped Sandwich Beams to Shock Loading". Journal of Applied Mechanics, Vol. 71, p. 386-401. #12;6Systems Sandwich Beams to Sho

88

Microstructural design in cellular materials. Progress report  

SciTech Connect

In last year`s continuation proposal the work outlined for the period January 1991--January 1992 was focused on microstructural design of cellular materials; specifically we suggested honeycomb-like microstructures and composite foams with sandwich cell walls. We also planned to examine natural cellular materials to see if their structure suggests ways in which engineering cellular materials might be improved. We planned to make cellular materials with several different microstructures; to characterize their microstructure; and to measure their mechanical properties.

Gibson, L.J.

1992-01-31

89

Tunable split-ring resonators for nonlinear negative-index metamaterials  

E-print Network

therein. 2. J. B. Pendry, A. J. Holden, W. J. Stewart, and I. Youngs, "Extremely low frequency plasmons, T. Koschny, and C. M. Soukoulis, "Magnetic response of metama- terials at 100-terahertz," Science. Boardman, and P. Egan, "Nonlinear surface waves in left-handed materials," Phys. Rev. E 69, 16617­9 (2004

90

Integrated design of structures, controls, and materials  

NASA Technical Reports Server (NTRS)

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.

Blankenship, G. L.

1994-01-01

91

A two-dimensional uniplanar transmission-line metamaterial with a negative index of refraction  

Microsoft Academic Search

A uniplanar transmission-line (TL) network has been loaded with lumped elements (chip or printed), enabling one to achieve a two-dimensional (2D) uniplanar negative-refractive-index (NRI) metamaterial. The metamaterial consists of a 2D array of unit cells, composed of TL sections connected in series and loaded in a specified manner. The unit cell dimensions can be designed to be much smaller than

Francis Elek; George V. Eleftheriades

2005-01-01

92

Design, discovery and growth of novel materials  

SciTech Connect

This editorial introduces the special issue on design, discovery, and growth of novel materials. The papers of this special issue review and reveal technical details of of how specific growths are developed and implemented.

Canfield, Paul

2012-06-07

93

Microstructural design in cellular materials. Final report  

SciTech Connect

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.

Gibson, L.J.

1995-12-01

94

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

METAMATERIALS: Large-area printed 3D negative-index metamaterial is flexible - Laser Focus World-area printed 3D negative-index metamaterial is flexible METAMATERIALS: Large-area printed 3D negative, with the advent of a printing process that produces large-area 3D multilayer optical NIMs --8.7 Ã? 8.7 cm square

Rogers, John A.

95

Functionally graded materials: Design, processing and applications  

SciTech Connect

In a Functionally Graded Material (FGM), the composition and structure gradually change over volume, resulting in corresponding changes in the properties of the material. By applying the many possibilities inherent in the FGM concept, it is anticipated that materials will be improved and new functions for them created. A comprehensive description of design, modeling, processing, and evaluation of FGMs as well as their applications is covered in this book. The contents include: lessons from nature; graded microstructures; modeling and design; characterization of properties; processing and fabrication; applications; and summary and outlook.

Miyamoto, Y. [ed.] [Osaka Univ. (JP); Kaysser, W.A.; Rabin, B.H.; Kawasaki, A.; Ford, R.G. [eds.

1999-09-01

96

Mimicry of natural material designs and processes  

NASA Astrophysics Data System (ADS)

Biological structural materials, although composed of unremarkable substances synthesized at low temperatures, often exhibit superior mechanical properties. In particular, the quality in which nearly all biologically derived materials excel is toughness. The advantageous mechanical properties are attributable to the hierarchical, composite, structural arrangements common to biological systems. Materials scientists and engineers have increasingly recognized that biological designs or processing approaches applied to man-made materials (biomimesis) may offer improvements in performance over conventional designs and fabrication methods. In this survey, the structures and processing routes of marine shells, avian eggshells, wood, bone, and insect cuticle are briefly reviewed, and biomimesis research inspired by these materials is discussed. In addition, this paper describes and summarizes the applications of biomineralization, self-assembly, and templating with proteins to the fabrication of thin ceramic films and nanostructure devices.

Bond, G. M.; Richman, R. H.; McNaughton, W. P.

1995-06-01

97

Hybrid materials design for SOFC interconnect applications  

NASA Astrophysics Data System (ADS)

Solid oxide fuel cells (SOFCs) offer distinct advantages when compared with alternative energy conversion techniques; however, problems with degradation, particularly interconnect degradation, are currently hindering adoption. One potential solution to minimize interconnect degradation is the use of novel hybrid materials which leverage the composite properties of well characterized, commercially available materials to create a new superior material. A model hybrid material has been developed based on functional laminate construction. A corrosion resistant Ni-200 layer was roll clad onto an inexpensive, low CTE 430 SS Core material. Finally, a conductivity boosting manganese cobalt spinel coating was applied using wet powder spray to the surface. This model material allows us to explore the orthogonal nature of different interconnect functions and their related properties and performance by utilizing our comprehensive screening procedure. Utilizing a factorial design experiment, the effects of simulated SOFC conditions on a model material was investigated through a series of tests. Oxide structure and morphology were investigated using XRD and SEM analysis, respectively, followed by high temperature conductivity testing. Cross sectional composition analysis was performed utilizing AES and optical microscopy evaluated using reflected light optical microscopy. Finally, elevated tensile testing and dilatometry provided mechanical data throughout the temperature range of interest. This broad screening process allows us to elucidate previously unknown connections between materials properties, operational parameters, and system performance. Interconnect resistance was demonstrated to be chiefly a function of surface resistance, more specifically surface chemistry, and operation temperature reductions could cause order of magnitude increases in resistance. Corrosion resistance, as expected, proved to be most closely dependent on laminate composition, although surface chemistry did affect oxidation rate. Surprisingly, thermal expansion was equally a function of laminate composition and surface oxidation rate. Ideally, the conclusions and design recommendations provided by this work will enable a new approach to functional design hybrid material interconnects.

Casteel, Micah

98

4.510/4.501 Materializing Design  

E-print Network

(Mon-Wed) TEXT Refabricated Architecture ­ Kerin & Timberlake Digital Design and Manufacturing ­ Schodek Digital Fabrications ­ Architectural and Material Techniques ­ Lisa Iwamoto COURSE DESCRIPTION AND REQUIREMENTS As information rich industries such as news and media, furniture manufacturing and automobile

Entekhabi, Dara

99

Principles for Designing Language Teaching Materials.  

ERIC Educational Resources Information Center

Key principles for designing language teaching materials are presented. They relate to the following: links with the curriculum; authenticity regarding text and task; stimulating interaction; allowing focus on formal aspects of the language; encouraging development of learning skills; and applying language skills to the wider world. (10…

Nunan, David

1988-01-01

100

Microstructure Sensitive Design: A Quantitative Approach to New Materials Development.  

National Technical Information Service (NTIS)

The central goal of the project is to develop a new spectral method for design of polycrystalline materials. The methodology (MSD) differs from other materials design approaches in that all components of the materials design enterprise are communicated in...

B. L. Adams, S. R. Kalidindi

2005-01-01

101

Saving Material with Systematic Process Designs  

NASA Astrophysics Data System (ADS)

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.

Kerausch, M.

2011-08-01

102

Computational Materials Program for Alloy Design  

NASA Technical Reports Server (NTRS)

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.

Bozzolo, Guillermo

2005-01-01

103

Peptoid polymers: a highly designable bioinspired material.  

PubMed

Bioinspired polymeric materials are attracting increasing attention due to significant advantages over their natural counterparts: the ability to precisely tune their structures over a broad range of chemical and physical properties, increased stability, and improved processability. Polypeptoids, a promising class of bioinspired polymer based on a N-substituted glycine backbone, have a number of unique properties that bridge the material gap between proteins and bulk polymers. Peptoids combine the sequence specificity of biopolymers with the simpler intra/intermolecular interactions and robustness of traditional synthetic polymers. They are highly designable because hundreds of chemically diverse side chains can be introduced from simple building blocks. Peptoid polymers can be prepared by two distinct synthetic techniques offering access to two material subclasses: (1) automated solid-phase synthesis which enables precision sequence control and near absolute monodispersity up to chain lengths of ~50 monomers, and (2) a classical polymerization approach which allows access to higher molecular weights and larger-scale yields, but with less control over length and sequence. This combination of facile synthetic approaches makes polypeptoids a highly tunable, rapid polymer prototyping platform to investigate new materials that are intermediate between proteins and bulk polymers, in both their structure and their properties. In this paper, we review the methods to synthesize peptoid polymers and their applications in biomedicine and nanoscience, as both sequence-specific materials and as bulk polymers. PMID:23721608

Sun, Jing; Zuckermann, Ronald N

2013-06-25

104

Numerical simulations of negative-index refraction in wedge-shaped metamaterials Z. G. Dong, S. N. Zhu,* and H. Liu  

E-print Network

confirmed that negative index of refraction indeed exists in such a composite metamaterial and also provided as experimentally to better understand such composite structures. Several meth- ods have been used to verify whether in the real- ized left-handed band very narrow bandwidths in micro- wave region 14 . Furthermore, although

Cao, Wenwu

105

Use of advanced composite materials for innovative building design solutions/  

E-print Network

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 ...

Lau, Tak-bun, Denvid

2009-01-01

106

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

Code of Federal Regulations, 2011 CFR

...strength properties and material design values. 25.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General...strength properties and material design values. (a)...

2011-01-01

107

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

Code of Federal Regulations, 2013 CFR

...strength properties and material design values. 25.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General...strength properties and material design values. (a)...

2013-01-01

108

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

Code of Federal Regulations, 2012 CFR

...strength properties and material design values. 25.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General...strength properties and material design values. (a)...

2012-01-01

109

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

...strength properties and material design values. 25.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General...strength properties and material design values. (a)...

2014-01-01

110

Designing Teaching Materials for Learning Problem Solving in Technology Education.  

ERIC Educational Resources Information Center

Considers domain-specific design specifications in the process of designing teaching materials for learning problem solving in technology education in order to raise learning outcomes with these materials. Focuses on a construction problem (open-ended) and an explanation problem (constrained). Compares these newly-designed teaching materials with…

Doornekamp, B. G.

2001-01-01

111

Design concepts for pressurized lunar shelters utilizing indigenous materials  

NASA Technical Reports Server (NTRS)

The objective is to design a pressurized shelter build of indigenous lunar material. The topics are presented in viewgraph form and include the following: lunar conditions which impact design; secondary factors; review of previously proposed concepts; cross section of assembly facility; rationale for indigenous materials; indigenous material choices; cast basalt properties; design variables; design 1, cylindrical segments; construction sequence; design 2, arch-slabs with post-tensioned ring girders; and future research.

Happel, John Amin; Willam, Kaspar; Shing, Benson

1991-01-01

112

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

NASA Astrophysics Data System (ADS)

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

Rajan, Krishna

2008-03-01

113

Nanoscale material design for photovoltaic applications  

NASA Astrophysics Data System (ADS)

Solar cell technology directly converts the clean, abundant energy of the sun into electricity. To build solar cell modules with low cost and high energy conversion efficiency, nanomaterials such as nanowires, nanotubes and quantum dots are very promising candidates, due to their novel thermal, electrical, and optical properties. This research seeks to use silicon nanowire, carbon nanotube, and semiconductor quantum dot to achieve high optical absorption and low electron-phonon coupling. Multiscale simulation and experiments are combined to investigate the thermal radiative properties of nanowire/nanotube array structures and the electron-phonon interaction in semiconductor quantum dots. Optical properties of nanowire/nanotube structures are numerically investigated by combined ab initio calculation and computational electromagnetic calculations. At the atomic scale, ab initio calculations based on density functional theory are performed to evaluate the spectral dielectric function of the material using the initial atomic structure as the only input parameter. This method considers different absorption mechanisms from far infrared to visible spectrum, and its effectiveness is demonstrated using the material GaAs and small carbon nanotubes. At the nanoscale, the predicted dielectric function of nanowire/nanotube is used as an input parameter in finite-difference time-domain method, so that the optical properties of devices such as nanowire/nanotube arrays can be obtained. Based on this scheme, we have shown that the vertically aligned multiwalled carbon nanotube arrays are nearly perfect absorber in the visible spectrum. Silicon nanowire arrays are less absorptive than carbon nanotube, but we propose and demonstrate that their optical absorption can be greatly enhanced by introducing structural randomness, including random positioning, diameter and length. The enhanced optical absorption implies potential enhancement of the overall efficiency of nanotube/nanowire array solar cells. Phonon-assisted electron decay in semiconductor quantum dots is also investigated in this work. In semiconductor solar cell, a large portion of energy loss is by the fast hot electron cooling, in which a high energy electron decays to the electronic band gap by creating a series of phonons. The excessive electrical energy is then converted to heat and wasted, so that the total photovoltaic energy conversion efficiency is limited. The electron decay rate reduces in semiconductor quantum dots, due to the discrete electron energy levels created by quantum confinement. To design quantum dots with the slowest decay rate, we use the non-adiabatic molecular dynamics to perform real-time simulations of the phonon-assisted electron decay process. This method is based on time-dependent density functional theory, and can directly predict the phonon-assisted electron decay time using the initial quantum dot structure as the only input. The numerical simulation shows that the phonon-induced electron decay can be slowed down in a small PbSe quantum dot. The temperature-dependent relaxation in this quantum dot is also studied, which helps us to propose a multi-channel relaxation mechanism. This mechanism provides new insights to the understanding of electron decay process in quantum dots. The results from this study have potentially important applications in solar energy harvesting and radiative thermal management. It offers a new perspective of nanoscale engineering of materials to achieve more efficient photovoltaic energy conversion.

Bao, Hua

114

FOREWORD: Computational methodologies for designing materials Computational methodologies for designing materials  

NASA Astrophysics Data System (ADS)

It would be fair to say that in the past few decades, theory and computer modeling have played a major role in elucidating the microscopic factors that dictate the properties of functional novel materials. Together with advances in experimental techniques, theoretical methods are becoming increasingly capable of predicting properties of materials at different length scales, thereby bringing in sight the long-sought goal of designing material properties according to need. Advances in computer technology and their availability at a reasonable cost around the world have made tit all the more urgent to disseminate what is now known about these modern computational techniques. In this special issue on computational methodologies for materials by design we have tried to solicit articles from authors whose works collectively represent the microcosm of developments in the area. This turned out to be a difficult task for a variety of reasons, not the least of which is space limitation in this special issue. Nevertheless, we gathered twenty articles that represent some of the important directions in which theory and modeling are proceeding in the general effort to capture the ability to produce materials by design. The majority of papers presented here focus on technique developments that are expected to uncover further the fundamental processes responsible for material properties, and for their growth modes and morphological evolutions. As for material properties, some of the articles here address the challenges that continue to emerge from attempts at accurate descriptions of magnetic properties, of electronically excited states, and of sparse matter, all of which demand new looks at density functional theory (DFT). I should hasten to add that much of the success in accurate computational modeling of materials emanates from the remarkable predictive power of DFT, without which we would not be able to place the subject on firm theoretical grounds. As we know and will also see from the collection of works here, DFT also provides a platform for testing, improving, and evaluating the feasibility of more approximate methods whose need has become even more urgent. This is understandable since functional materials, given their limited translational symmetry, necessitate the usage of unit cells with a large number of atoms (sometimes in hundreds). Even if DFT codes were efficient enough to handle several hundred atoms in the calculational super-cell, the extraction of equilibrium geometry for such systems requires injection of more efficient methodology, as geometry is the input and not the output of a DFT calculation. Equally important is the need to calculate the temperature dependencies of material properties and for simulations to be carried out at length scales suitable for incorporating kinetic effects from competing processes and cooperative effects from constituting entities. It is true that codes based on DFT are becoming increasingly efficient and that methods such as ab initio molecular dynamics simulations are available for simulations of systems at temperatures above 0 K. However, such approaches still have a way to go before they can be readily applied to materials with complex geometries and composition, and for time and length scales that are relevant to realistic environments in the laboratory. Several articles here represent some of the recent advances towards 'multi-scale' modeling of materials. Among the articles that focus exclusively on DFT, the contribution by Weinert et al [1] summarizes some of the advances made to better describe magnetic properties and entropic effects. The article by Kyrychenko and Ullrich [2] discusses recent developments in time dependent DFT to describe transport properties and absorption spectra of solids. Their model allows for a comprehensive treatment of electron--electron interaction, screening and correlation effects which are necessary for proper description of properties of the excited state. The contribution by Langreth and co-workers [3] summarizes their recent efforts at incorpo

Rahman, Talat S.

2009-02-01

115

Solid-fluid mixture microstructure design of composite materials with application to tissue engineering scaffold design  

Microsoft Academic Search

The ability to design the material microstructure brings the use of composite materials into the next generation. In this paper, we report pioneering research to implement the computational material microstructure design into the internal architecture design for a tissue engineering scaffold. A tissue engineering design postulate is that scaffolds should match specified healthy tissue stiffness, while concurrently providing sufficient porosity

Cheng-Yu Lin

2005-01-01

116

Print material content and design: is it relevant to effectiveness?  

Microsoft Academic Search

Printed materials are widely used in cancer education. There are a considerable number of guidelines in the literature on the content and design characteristics of print materials. However, there is little outcome-based evidence about whether materials containing these char- acteristics are more effective under real-world conditions. Six pamphlets were designed such that two had most of these characteristics, one had

C. L. Paul; S. Redman; R. W. Sanson-Fisher

2003-01-01

117

Thermoplastics as engineering materials: The mechanics, materials, design, processing link  

Microsoft Academic Search

While the use of plastics has been growing at a significant pace because of weight reduction, ease of fabrication of complex shapes, and cost reduction resulting from function integration, the engineering applications of plastics have only become important in the past fifteen years. An inadequate understanding of the mechanics issues underlying the close coupling among the design, the processing (fabrication),

Vijay K. Stokes

1995-01-01

118

COMPUTATIONAL DESIGN OF MULTIPHASE MATERIALS AT THE MESOLEVEL  

Microsoft Academic Search

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

Leon Mishnaevsky Jr; Nils Lippmann; Siegfried Schmauder

2001-01-01

119

Piezoactuator Design Considering the Optimum Placement of FGM Piezoelectric Material  

E-print Network

Piezoactuator Design Considering the Optimum Placement of FGM Piezoelectric Material Ronny C has been explored in piezoelectric materials to improve properties and to increase the lifetime of piezoelectric actuators. Elastic, piezoelectric, and dielectric properties are graded along the thickness

Paulino, Glaucio H.

120

Material, process, and product design of thermoplastic composite materials  

NASA Astrophysics Data System (ADS)

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

Dai, Heming

121

Multilayer filter design with high K materials  

NASA Astrophysics Data System (ADS)

A novel approach to filter design is presented. A high-K multilayer coupled line filter is designed for optimal performance within a dielectric resonator of rectangular cross section. The multilayer filter is shown to have a performance comparable to its planar counterpart as well as the Lange coupler while maintaining the design advantages that come with the multilayer approach to filter design such as increased flexibility in managing parameter constraints. The performance of the rectangular cross sectioned resonator in terms of modal response and resonant frequency has been evaluated through mathematical derivation and simulation. The reader will find the step by step process to designing the resonant structure as well as a MATLAB script that will graphically display the effect changing various parameters may have on resonator size to assist in the design analysis. The resonator has been designed to provide a finite package in terms of space and performance so that it may house the multilayer filter on a printed circuit board for ease of system implementation. The proposed design with analysis will prove useful for all multilayer coupled line filter types that may take advantage of the uniform environment provided by the finite packaging of the dielectric resonator. As with any microwave system, considerable effort must be put forth to maintain signal integrity throughout the delivery process from the signal input to reception at the output. As a result a large amount of effort and research has gone into answering the question of how to efficiently feed both a dielectric resonator filter of rectangular cross section as well as a coupled line filter that would be embedded within the resonators confines. Several methods for feeding have been explored and reported on. Of the feeding methods reported on the most feasible design includes a unique microstrip delivery to the embedded multilayer filter as pictured here.* *Please refer to dissertation for diagram.

Curtis, Nathaniel, II

122

Bridge : information as material for design  

E-print Network

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 ...

Kaijima, Sawako, 1976-

2005-01-01

123

Design and fabrication of materials with desired deformation behavior  

Microsoft Academic Search

This paper introduces a data-driven process for designing and fab- ricating materials with desired deformation behavior. Our process starts with measuring deformation properties of base materials. For each base material we acquire a set of example deformations, and we represent the material as a non-linear stress-strain relationship in a finite-element model. We have validated our material measure- ment process by

Bernd Bickel; Moritz Bächer; Miguel A. Otaduy; Hyunho Richard Lee; Hanspeter Pfister; Markus H. Gross; Wojciech Matusik

2010-01-01

124

Design and fabrication of materials with desired deformation behavior  

Microsoft Academic Search

This paper introduces a data-driven process for designing and fabricating materials with desired deformation behavior. Our process starts with measuring deformation properties of base materials. For each base material we acquire a set of example deformations, and we represent the material as a non-linear stress-strain relationship in a finite-element model. We have validated our material measurement process by comparing simulations

Bernd Bickel; Moritz Bächer; Miguel A. Otaduy; Hyunho Richard Lee; Hanspeter Pfister; Markus Gross; Wojciech Matusik

2010-01-01

125

Chemical design of solid inorganic materials  

Microsoft Academic Search

Newer strategies for the synthesis of inorganic solids have made a great impact on present-day materials chemistry. In this article, typical case studies of synthesis involving new methods and soft chemical routes are discussed besides recent results from nebulized spray pyrolysis and synthesis of nanoscale metal and alloy particles. Introduct ion Strategies for the synthesis of inorganic solids are being

C. N. R. Rao

1997-01-01

126

Construction Design anD Materials  

E-print Network

the Colorado State Forest Service at 970-491-6303 or online at csfs.colostate.edu #12;About the Author Peter, resource conserving materials. Peter was a firefighter and a officer in a high-risk mountain fire district, who over many years have developed, to this date, one of the most compre- hensive and systematic

127

Reticular synthesis and the design of new materials  

Microsoft Academic Search

The long-standing challenge of designing and constructing new crystalline solid-state materials from molecular building blocks is just beginning to be addressed with success. A conceptual approach that requires the use of secondary building units to direct the assembly of ordered frameworks epitomizes this process: we call this approach reticular synthesis. This chemistry has yielded materials designed to have predetermined structures,

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

2003-01-01

128

Impact of low activation materials on fusion reactor design  

Microsoft Academic Search

The following impact of low activation materials to the fusion reactor design are described based on the design of five fusion power reactors with different structural material\\/coolant combinations. (1) Reduce the radioactive impact to the environment in case of severe accidents. (2) Reduce the radioactive impact to the environment during normal operation. (3) Reduce the decay heat during the maintenance

Y. Seki; T Tabara; I Aoki; S Ueda; S Nishio; R Kurihara

1998-01-01

129

Designing Training Materials for Developing Countries.  

ERIC Educational Resources Information Center

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

Rosenweig, Fred

1984-01-01

130

Designing Spider Silk Genes for Materials Applications.  

National Technical Information Service (NTIS)

This project is designed to create new proteins based on naturally occurring spider silk proteins with the goal of controlling elasticity and tensile strength in fibers spun from the proteins. The new genes have been constructed in year 1, the proteins ha...

R. V. Lewis

2006-01-01

131

Computational materials design for energy applications  

NASA Astrophysics Data System (ADS)

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.

Ozolins, Vidvuds

2013-03-01

132

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

ERIC Educational Resources Information Center

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…

Wang, Hei-Chia; Hsu, Chien-Wei

2006-01-01

133

Concurrent materials and process selection in conceptual design  

SciTech Connect

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.

Kleban, S.D.

1998-07-01

134

Material transformation designing shape changing interfaces enabled by programmable material anisotropy  

E-print Network

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 ...

Ou, Jifei

2014-01-01

135

Characterization of material properties for tunable reflectarray antenna design  

NASA Astrophysics Data System (ADS)

The emerging field of communications has increased the demand of electronically tunable reflectarray antennas. Substrate material properties play an important role in the design of reflectarray antennas. Variable permittivity materials such as liquid crystals and ferroelectrics have received great deal of attention due to their non-linear material properties. A comparative analysis between the properties of liquid crystals and ferroelectrics for tunable reflectarray antenna design has been carried out by using Finite Integral Method (FIM). A thorough investigation based on reflectarray design analysis and tunable bias voltages of different non-linear materials is provided. It has been shown that due to higher dielectric permittivity values of non-linear materials, ferroelectrics require higher bias voltages for electronic tunability, as compared to liquid crystal materials. Barium strontium titanate (BST) with a dielectric permittivity ranging from 300 to 360 has been used as a ferroelectric substrate material to design a rectangular patch reflectarray which offers a frequency tunability of 3 GHz. The results show that ferroelectrics are only applicable for high frequency reflectarray operation due to materials' higher permittivity values. Furthermore a rectangular patch reflectarray antenna printed on 1 mm thick different liquid crystal materials has also been designed based on FIM. It has been shown that as the dielectric anisotropy of substrate material increases from 0.17 to 0.45, the frequency tunablity and dynamic phase range of reflectarray antenna also increase from 372 MHz to 795 MHz and 90° to 160°, respectively.

Ismail, M. Y.; Dahri, M. Hashim; Zaihasra, W. N.

2013-05-01

136

Material Compatibility with Space Storable Propellants. Design Guidebook  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

137

Designing Educative Curriculum Materials: A Theoretically and Empirically Driven Process  

ERIC Educational Resources Information Center

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

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

2014-01-01

138

Nondestructive evaluation of composite materials - A design philosophy  

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

139

Characterization of elastomeric materials with application to design  

NASA Technical Reports Server (NTRS)

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.

Bower, Mark V.

1986-01-01

140

Photovoltaic module encapsulation design and materials selection, volume 1  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

141

Designing Radiation Resistance in Materials for Fusion Energy  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

142

Design of meta-materials with novel thermoelastic properties  

NASA Astrophysics Data System (ADS)

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

Watts, Seth

143

Optimal Experiment Design for Thermal Characterization of Functionally Graded Materials.  

National Technical Information Service (NTIS)

The purpose of the project was to investigate methods to accurately verify that designed , materials meet thermal specifications. The project involved heat transfer calculations and optimization studies, and no laboratory experiments were performed. One p...

K. D. Cole

2003-01-01

144

Optimal Design and Scheduling of Unsteady State Material Recovery Networks  

E-print Network

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...

Rabie, Arwa H.

2010-01-14

145

Socio-material design for computer mediated social sensemaking  

E-print Network

control and understand the implications of their participation. Author Keywords Social media; socialSocio-material design for computer mediated social sensemaking Abstract Telemonitoring healthcare because of the difficulty interpreting sensor data remotely. Computer-Mediated Social Sensemaking (CMSS

Edinburgh, University of

146

First Principles Modeling for Research and Design of New Materials  

E-print Network

First principles computation can be used to investigate an design materials in ways that can not be achieved with experimental means. We show how computations can be used to rapidly capture the essential physics that ...

Ceder, Gerbrand

147

Material evaluation and selection processes to enable design for manufacture  

E-print Network

In order to optimize product designs it is necessary to quickly evaluate many candidate materials in terms of performance and processing costs. Evaluation using physical prototypes yields concrete results but is time ...

Abler, Craig Bennett, 1975-

2006-01-01

148

Inductor Design Methods With Low-Permeability RF Core Materials  

E-print Network

This paper presents a design procedure for inductors based on low-permeability magnetic materials, for use in very high frequency power conversion. The proposed procedure offers an easy and fast way to compare different ...

Han, Yehui

149

SketchSpace: Designing Interactive Behaviors with Passive Materials  

E-print Network

sketching tool that is as seamless as working with common design materials, such as tape or foam core-on and, consequently, triggers the serendipitous realizations arrived at with a concrete artifact [7

Benko, Hrvoje

150

Evaluation of materials and design modifications for aircraft brakes  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

151

The International Thermonuclear Experimental Reactor (ITER): Design and materials selection  

SciTech Connect

The success of ITER relies on aggressive design of the superconducting magnet systems. This design emphasized high radiation-damage tolerance, acceptance of high nuclear heat loads, and high operational stresses in the Toroidal Field (TF) magnets. The design of the Central Solenoid (CS) magnets, although they will be well shielded from the plasma, is equally aggressive due to the need for very high magnetic fields (14 T) and long term operation at high cyclic stresses. Success of these magnet designs depends, in part, on sound selection and fabrication of materials for structural, superconducting, and insulating components. Here we review the design of ITER and the selection of structural materials for some of the systems that will operate at cryogenic temperatures. In addition we will introduce some of the data that the materials selection is based on and suggest opportunities for future research in support of ITER. 10 refs., 1 fig., 4 tabs.

Summers, L.T.; Miller, J.R.; Heim, J.R.

1989-08-08

152

Designing Radiation Resistance in Materials for Fusion Energy  

SciTech Connect

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.

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

2014-01-01

153

The Instructional Design Transition from Distance to Flexible Delivery Materials.  

ERIC Educational Resources Information Center

The techniques of instructional design that have been applied to the preparation of distance materials for independent learning are now being applied to the production of materials that are to be used in flexible delivery of subjects. This allows subjects to be offered which require face to face work but can also have a major component of…

Ramsay, Grahame

154

Design and testing of innovative materials for passive fire protection  

Microsoft Academic Search

This study focuses on the characterization of panels for passive fire protection made with new composite materials, based on basalt fibers and both organic and inorganic impregnating matrixes. These materials were experimentally investigated to assess their suitability to bear strict exercise conditions imposed by accidental flame impingement. To this end, an experimental facility was specifically designed to simulate jet fires

Gabriele Landucci; Francesco Rossi; Cristiano Nicolella; Severino Zanelli

2009-01-01

155

The high-throughput highway to computational materials design  

NASA Astrophysics Data System (ADS)

High-throughput computational materials design is an emerging area of materials science. By combining advanced thermodynamic and electronic-structure methods with intelligent data mining and database construction, and exploiting the power of current supercomputer architectures, scientists generate, manage and analyse enormous data repositories for the discovery of novel materials. In this Review we provide a current snapshot of this rapidly evolving field, and highlight the challenges and opportunities that lie ahead.

Curtarolo, Stefano; Hart, Gus L. W.; Nardelli, Marco Buongiorno; Mingo, Natalio; Sanvito, Stefano; Levy, Ohad

2013-03-01

156

A tangible design tool for sketching materials in products  

Microsoft Academic Search

Industrial designers make sketches and physical models to start and develop ideas and concept designs. Such representations have advantages that they support fast, intuitive, rich, sensory exploration of solutions. Although existing tools and techniques provide adequate support where the shape of the product is concerned, the exploration of surface qualities such as material and printed graphics is supported to a

Daniel Saakes; Pieter Jan Stappers

2009-01-01

157

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

NASA Technical Reports Server (NTRS)

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.

Inman, Daniel J.; Cudney, Harley H.

2000-01-01

158

FOREWORD: Computational methodologies for designing materials Computational methodologies for designing materials  

Microsoft Academic Search

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

Talat S. Rahman

2009-01-01

159

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

PubMed

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

Chau, Kenneth J; Lezec, Henri J

2012-04-23

160

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

E-print Network

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 ...

Coelho, Marcelo

2008-01-01

161

Optimal design of piezoelectric materials and devices for energy harvesting  

NASA Astrophysics Data System (ADS)

Piezoelectric vibration energy harvesters (PVEHs) have received considerable attention as an enabling technology for self-powered wireless sensor networks. However, the biggest challenge with PVEHs has been their insufficient power generation for practical applications, which necessitates creative and disruptive materials and structure design on various scales. In this work, a model-based design study is performed that includes structural, materials, and device-level power optimizations of PVEHs. The optimization results help in understanding the behavior of the device performance, such as voltage and power, when the devices are optimized under various operating conditions, including input operating frequencies and mechanical damping. Furthermore, the optimization provides both an optimal device design scheme for power improvement and a better understanding of the correlation between the material property and the energy-harvesting output performance.

Kim, Miso; Dugundji, John; Wardle, Brian L.

2013-06-01

162

Modular design in natural and biomimetic soft materials.  

PubMed

Under eons of evolutionary and environmental pressure, biological systems have developed strong and lightweight peptide-based polymeric materials by using the 20 naturally occurring amino acids as principal monomeric units. These materials outperform their man-made counterparts in the following ways: 1) multifunctionality/tunability, 2) adaptability/stimuli-responsiveness, 3) synthesis and processing under ambient and aqueous conditions, and 4) recyclability and biodegradability. The universal design strategy that affords these advanced properties involves "bottom-up" synthesis and modular, hierarchical organization both within and across multiple length-scales. The field of "biomimicry"-elucidating and co-opting nature's basic material design principles and molecular building blocks-is rapidly evolving. This Review describes what has been discovered about the structure and molecular mechanisms of natural polymeric materials, as well as the progress towards synthetic "mimics" of these remarkable systems. PMID:21898722

Kushner, Aaron M; Guan, Zhibin

2011-09-19

163

Designer disordered materials with large, complete photonic band gaps  

PubMed Central

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

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

2009-01-01

164

LUTE primary mirror materials and design study report  

NASA Technical Reports Server (NTRS)

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.

Ruthven, Greg

1993-01-01

165

Accelerating the design of biomimetic materials by integrating RNA-seq with proteomics and materials science.  

PubMed

Efforts to engineer new materials inspired by biological structures are hampered by the lack of genomic data from many model organisms studied in biomimetic research. Here we show that biomimetic engineering can be accelerated by integrating high-throughput RNA-seq with proteomics and advanced materials characterization. This approach can be applied to a broad range of systems, as we illustrate by investigating diverse high-performance biological materials involved in embryo protection, adhesion and predation. In one example, we rapidly engineer recombinant squid sucker ring teeth proteins into a range of structural and functional materials, including nanopatterned surfaces and photo-cross-linked films that exceed the mechanical properties of most natural and synthetic polymers. Integrating RNA-seq with proteomics and materials science facilitates the molecular characterization of natural materials and the effective translation of their molecular designs into a wide range of bio-inspired materials. PMID:24013196

Guerette, Paul A; Hoon, Shawn; Seow, Yiqi; Raida, Manfred; Masic, Admir; Wong, Fong T; Ho, Vincent H B; Kong, Kiat Whye; Demirel, Melik C; Pena-Francesch, Abdon; Amini, Shahrouz; Tay, Gavin Z; Ding, Dawei; Miserez, Ali

2013-10-01

166

SUSTAINABLE INFRASTRUCTURE MATERIAL DESIGN Michael D. Lepech1  

E-print Network

SUSTAINABLE INFRASTRUCTURE MATERIAL DESIGN Michael D. Lepech1 , Victor C. Li1 , and Gregory A Engineering 2 Center for Sustainable Systems, School of Natural Resources and Environment University, sustainability has not been included in most infrastructure systems on any level. However, the engineering

Lepech, Michael D.

167

Iterative EM Design of an MRI Magnet Using HTS Materials  

Microsoft Academic Search

Conventional superconducting MRI magnet electromagnetic (EM) design involves the critical parameters of the magnet field and dimensional requirements, plus the low temperature superconductor (LTS) wire properties. When using HTS material for an MRI magnet, in addition to the conventional characteristics of a superconductor, the wire and the joint resistance need also to be considered. This is mainly due to the

Minfeng Xu; Michele Ogle; Xianrui Huang; Kathleen Amm; Evangelos T. Laskaris

2007-01-01

168

Materials Process Design and Control Laboratory Cornell University  

E-print Network

certain process satisfy some specific experimentally determined statistics of grain size distribution. 3D. Rhodes Hall Cornell University Ithaca, NY 14853-3801 Email: bw336@cornell.edu URL: http;Materials Process Design and Control Laboratory Cornell University Primary Development Employ model

Zabaras, Nicholas J.

169

Size effect of lattice material and minimum weight design  

NASA Astrophysics Data System (ADS)

The size effects of microstructure of lattice materials on structural analysis and minimum weight design are studied with extented multiscale finite element method (EMsFEM) in the paper. With the same volume of base material and configuration, the structural displacement and maximum axial stress of micro-rod of lattice structures with different sizes of microstructure are analyzed and compared. It is pointed out that different from the traditional mathematical homogenization method, EMsFEM is suitable for analyzing the structures which is constituted with lattice materials and composed of quantities of finite-sized micro-rods. The minimum weight design of structures composed of lattice material is studied with downscaling calculation of EMs-FEM under stress constraints of micro-rods. The optimal design results show that the weight of the structure increases with the decrease of the size of basic sub-unit cells. The paper presents a new approach for analysis and optimization of lattice materials in complex engineering constructions. [Figure not available: see fulltext.

Yan, Jun; Hu, Wen-Bo; Wang, Zhen-Hua; Duan, Zun-Yi

2014-04-01

170

Impact of low activation materials on fusion reactor design  

NASA Astrophysics Data System (ADS)

The following impact of low activation materials to the fusion reactor design are described based on the design of five fusion power reactors with different structural material/coolant combinations. (1) Reduce the radioactive impact to the environment in case of severe accidents. (2) Reduce the radioactive impact to the environment during normal operation. (3) Reduce the decay heat during the maintenance and in case of loss of cooling accidents. (4) Reduce the gamma-ray dose during the maintenance. (5) Reduce the amount and lower the level of radioactive waste from replaced components and at the decommissioning of a fusion reactor. In order to reduce environmental impact in case of severe accidents to the level such as to enable construction of a fusion reactor near big cities, the low activation material must be of very low activity such as may only be achievable by SiC/SiC composites.

Seki, Y.; Tabara, T.; Aoki, I.; Ueda, S.; Nishio, S.; Kurihara, R.

1998-10-01

171

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

Code of Federal Regulations, 2010 CFR

...and watertight bulkheads-materials and pressure design. 128.230 Section 128...EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.230 Penetrations of...watertight bulkheads—materials and pressure design. (a) Each piping...

2010-10-01

172

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

Code of Federal Regulations, 2010 CFR

...non-vital systems-materials and pressure design. 128.220 Section 128...EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.220 Class II non-vital systems—materials and pressure design. (a) Except as...

2010-10-01

173

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

Code of Federal Regulations, 2011 CFR

...pneumatic power and control-materials and pressure design. 128.240 Section 128...EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard...

2011-10-01

174

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

Code of Federal Regulations, 2011 CFR

...and watertight bulkheads-materials and pressure design. 128.230 Section 128...EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.230 Penetrations of...watertight bulkheads—materials and pressure design. (a) Each piping...

2011-10-01

175

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

Code of Federal Regulations, 2011 CFR

...non-vital systems-materials and pressure design. 128.220 Section 128...EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.220 Class II non-vital systems—materials and pressure design. (a) Except as...

2011-10-01

176

Designing ECM-mimetic materials using protein engineering.  

PubMed

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 20years, 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 (i) demonstrate exemplary use as matrices with cell-instructive and cell-responsive properties or (ii) demonstrate outstanding creativity in terms of novel molecular-level design and macro-level functionality. PMID:24365704

Cai, Lei; Heilshorn, Sarah C

2014-04-01

177

CubeSat Material Limits For Design for Demise  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

178

Design of electro-active polymer gels as actuator materials  

NASA Astrophysics Data System (ADS)

Smart materials, alternatively called active or adaptive, differ from passive materials in their sensing and activation capability. These materials can sense changes in environment such as: electric field, magnetic field, UV light, pH, temperature. They are capable of responding in numerous ways. Some change their stiffness properties (electro-rheological fluids), other deform (piezos, shape memory alloys, electrostrictive materials) or change optic properties (electrochromic polymers). Polymer gels are one of such materials which can change the shape, volume and even optical properties upon different applied stimuli. Due to their low stiffness property they are capable of having up to 100% of strain in a short time, order of seconds. Their motion resembles the one of biosystems, and they are often seen as possible artificial muscle materials. Despite their delicate nature, appropriate design can make them being used as actuator materials which can form controllable surfaces and mechanical switches. In this study several different groups of polymer gel material were investigated: (a) acrylamide based gels are sensitive to pH and electric field and respond in volume change, (b) polyacrylonitrile (PAN) gel is sensitive to pH and electric field and responds in axial strain and bending, (c) polyvinylalcohol (PVA) gel is sensitive to electric field and responds in axial strain and bending and (d) perfluorinated sulfonic acid membrane, Nafion RTM, is sensitive to electric field and responds in bending. Electro-mechanical and chemo-mechanical behavior of these materials is a function of a variety of phenomena: polymer structure, affinity of polymer to the solvent, charge distribution within material, type of solvent, elasticity of polymer matrix, etc. Modeling of this behavior is a task aimed to identify what is driving mechanism for activation and express it in a quantitative way in terms of deformation of material. In this work behavior of the most promising material as an actuator material, Nafion 117, was simulated. It was suggested that dominant phenomenon causing the material deformation is non-uniform water distribution within a material, that causes it to expand on one side and shrink on the other, macroscopically inducing bending of membrane. Uneven distribution of water is believed to be under the influence of two processes, electroosmosis and self-diffusion of free water.

Popovic, Suzana

179

Design of ceramic materials for chemical sensors with novel properties  

SciTech Connect

Recently, the search for novel functions has received increasing attention in the field of materials. Outstanding possibilities for innovative applications are given by electroceramics. One of the fields which may be improved by a different use of functional ceramics is that of chemical sensors. In fact, the materials conventionally used in this field show problems still to be solved, such as insufficient gas selectivity, inability to detect very low gas concentrations, and changing in sensing properties caused by surface contamination. One possible solution to these problems is the design of materials with novel detection mechanisms. The design of innovative properties may be achieved by integration or hybridization of materials with different properties. In this paper, examples of multiphase materials for humidity and gas sensors are reported, i.e., La{sub 2}CuO{sub 4}/ZnO p-n heterocontacts, Au/ZnO Schottky barriers, and sol-gel processed thin films of TiO{sub 2} with 10 at.% of K, based, respectively, on the interaction of p-type/n-type semiconductors, metal/ceramic, and conductor/insulator.

Traversa, E. [Univ. di Roma Tor Vergata (Italy). Dipt. di Scienze e Tecnologie Chimiche

1995-10-01

180

Bioinspiration from fish for smart material design and function  

NASA Astrophysics Data System (ADS)

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.

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

2011-09-01

181

Designed amyloid fibers as materials for selective carbon dioxide capture  

PubMed Central

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

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

2014-01-01

182

System design considerations for free-fall materials processing  

NASA Technical Reports Server (NTRS)

The design constraints for orbiting materials processing systems are dominated by the limitations of the flight vehicle/crew and not by the processes themselves. Although weight, size and power consumption are all factors in the design of normal laboratory equipment, their importance is increased orders of magnitude when the equipment must be used in an orbital facility. As a result, equipment intended for space flight may have little resemblance to normal laboratory apparatus although the function to be performed may be identical. The same considerations influence the design of the experiment itself. The processing requirements must be carefully understood in terms of basic physical parameters rather than defined in terms of equipment operation. Preliminary experiments and analysis are much more vital to the design of a space experiment than they are on earth where iterative development is relatively easy. Examples of these various considerations are illustrated with examples from the M518 and MA-010 systems. While these are specific systems, the conclusions apply to the design of flight materials processing systems both present and future.

Seidensticker, R. G.

1974-01-01

183

NSF Centers Will Use Nano-Interface Control and Bioengineering for Materials by Design  

NSF Publications Database

... Bioengineering for Materials by Design Scientists observed trapped electrical charge in an organic ... materials science and education beyond what is expected from any one Center. "Advanced materials are ...

184

Rational Design of Pathogen-Mimicking Amphiphilic Materials as Nanoadjuvants  

NASA Astrophysics Data System (ADS)

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.

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

185

Mechanical Design and Material Characterization of the Piezoelectric Energy Harvestor  

NASA Astrophysics Data System (ADS)

This paper is on the proposal of the methodology for the design and fabrication of the piezoelectric energy harvesting devices in viewpoint of the justification both structural and material properties. There has been developing various kinds of energy harvesting techniques using piezoelectric films. Most of them are for the justification of the design or the circuit. The output of the piezoelectric harvester is the product of the material and structural parts. It is, therefore, necessary to justify both of them simultaneously. In this paper cantilever structure was fabricated for the improvement of the power generation in the low frequency region. The resonant frequency and output voltage and charge from the following theory formula were calculated in this study.

Ichiki, M.; Komine, E.; Sueshige, K.; Iimura, K.; Kobayashi, T.; Kitahara, T.; Fujimoto, S.

2013-12-01

186

Design and engineering analysis of material procurement mobile operation platform  

NASA Astrophysics Data System (ADS)

The material procurement mobile operation platform (MPMOP) consists of six modules, including network operation, truck transportation, remote communication, satellite positioning, power supply and environment regulation. The MPMOP is designed to have six major functions, including online procurement, command control, remote communication, satellite positioning, information management and auxiliary decision. The paper implements an engineering analysis on the MPMOP from three aspects, including transportation transfinite, centroid, and power dissipation.

Ding, H.; Li, J.

2014-03-01

187

Thermo-magnetic materials for use in designing intelligent actuators  

SciTech Connect

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.

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

188

Overview on spallation target design concepts and related materials issues  

NASA Astrophysics Data System (ADS)

From a modest beginning of a few kW of beam power spallation sources have now evolved into systems that must be able to handle several MW, mostly delivered in short pulses of less than microsecond duration. The high radiation field and high instantaneous heat deposition which spallation targets, in particular for the new high power sources, are subject to have led to several different design concepts which aim at circumventing or reducing the deleterious effects on the materials in the targets. Efficient cooling and high neutron source density are competing requirements which can be best reconciled by moving the target material out of the reaction zone and removing the heat elsewhere before returning the material back into the proton beam. One option is the use of a flowing liquid metal, which has been the method of choice in most of the recent spallation source designs, but requires solutions to a variety of new problems, such as liquid metal corrosion, cavitation erosion and e.g. in the case of PbBi, or Pb, high temperature gradients. Using a rotating solid target is an option in certain cases but still has to cope with the instantaneous load levels. While it may help to keep the average heat load and radiation damage in the target material low and thus extend the target life time by more than an order of magnitude, it still has its own design and materials issues. Opportunities to carry out research in this field are rather limited because the effects can hardly be simulated off line and, apart from spallation targets in operation, almost no facilities are available.

Bauer, G. S.

2010-03-01

189

Design of standards for nondestructive assay of special nuclear material  

SciTech Connect

Nondestructive assay (NDA) of special nuclear material (SNM) involves a variety of measurement techniques, instruments, and nuclear materials. High-quality measurements require well-characterized SNM standards that represent the expected range of mass, chemical composition, and physical properties of the SNM to be measured. Due to the very limited commercial availability of NDA standards, facilities must usually produce their own standards, both to meet their specific measurement needs and to comply with existing regulations. This paper will describe the current extent to which NDA standards are commercially available. The authors will further describe the types of NDA standards used to calibrate and verify the measurement techniques commonly used in the safeguards of SNM. Several types of NDA standards will be discussed in detail to illustrate the considerations that go into specifying and designing traceable, representative standards for materials accounting measurements.

Smith, H.A. Jr.; Stewart, J.E. [Los Alamos National Lab., NM (United States); Ruhter W. [Lawrence Livermore National Lab., CA (United States)

1997-05-01

190

Fissile material storage vaults: Designing to enhance safety and efficiency  

SciTech Connect

There are several, sometimes conflicting, interests which must be accommodated in fissile material, storage vaults. These include criticality safety, radiation safety, fire protection, accountability, and safeguards in addition to the operational requirements of efficiency and, for automated vaults, reliability. A combination of these factors coupled with increasing demands on available vault space and the desire to minimize on-site transportation of special nuclear materials has resulted in current design and construction activities for three major fissile material storage vaults and the renovation of an existing vault at the Los Alamos National Laboratory. Two of these new vaults will be provided with automated stacker-retriever systems similar to those common in large warehouse operations while the third vault, being smaller and having less potential for radiation exposures will be operated in a hands-on mode.

McLaughlin, T.P.

1987-01-01

191

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

SciTech Connect

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.

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

2005-01-01

192

Design And Formability Of A New Composite Material  

SciTech Connect

Composite materials with metallic cover sheets have been established based on their low weight potential in industrial applications. Further requirements such as high stiffness of component, vibration damping and formability today are only partially met by these composites. For that reason, in current research work, great efforts are being made to develop materials which can be adapted to their later use and load in terms of improving noise, vibration and harshness. Thus, greater stiffness of component structure with a simultaneous reduction of weight can be achieved. This article presents a new composite material which consists of a plane sheet, a thin intermediate damping-layer and a sheet with formed elements to increase stiffness of component such as beads. The plane side can be used as the visible part side. The shape elements increase strength due to work hardening and can be used as design or functional elements. Thus, this composite material results in several advantages within the single layers. Possible flexibility in component design enables new semi-finished or tailored components.

Bolay, C.; Liewald, M. [Institute for Metal Forming Technology (IFU)-Holzgartenstr. 17, 70174 Stuttgart (Germany)

2011-05-04

193

Genetic algorithms in computational materials science and engineering: simulation and design of self-assembling materials  

Microsoft Academic Search

We introduce here two genetic algorithms that were developed in order to aid in the design of molecules for self-assembling materials. The first constructs molecules from sets of chemical building blocks, searching for candidates that are determined by an ancillary modeling program to assemble into low-energy aggregates. The results of running this Genetic Algorithm (GA) on a set of building

Milan Keser; Samuel I Stupp

2000-01-01

194

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

PubMed

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

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

2012-01-01

195

Design, processing, and materials for large-stroke actuators  

NASA Astrophysics Data System (ADS)

Adaptive optics (AO) applications in astronomy and vision science require deformable mirrors with larger stroke, higher packing density and at lower cost than currently available technology. The use of high-aspect ratio Micro-Electro- Mechanical Systems (MEMS) processing techniques to fabricate large-stroke actuators that can meet stroke, packing density and cost specifications for AO applications have been explored. Different actuator designs, materials and postprocessing procedures fabricated in two different high-aspect ratio processes have been investigated. These manufacturing processes allow high-precision multilayer fabrication, and both parallel plate and comb drive actuator deformable mirror designs have been created. Multilayer fabrication has reduced pull-in voltage requirements for large stroke comb-drive actuators. The design, modeling and simulation of these actuators are compared to experimental measurements of their pull-voltages, which characterizes their stiffness and maximum stroke.

Fernández, Bautista; Kubby, Joel

2007-02-01

196

Materials, design and processing of air encapsulated MEMS packaging  

NASA Astrophysics Data System (ADS)

This work uses a three-dimensional air cavity technology to improve the fabrication, and functionality of microelectronics devices, performance of on-board transmission lines, and packaging of micro-electromechanical systems (MEMS). The air cavity process makes use of the decomposition of a patterned sacrificial polymer followed by the diffusion of its by-products through a curing polymer overcoat to obtain the embedded air structure. Applications and research of air cavities have focused on simple designs that concentrate on the size and functionality of the particular device. However, a lack of guidelines for fabrication, materials used, and structural design has led to mechanical stability issues and processing refinements. This work investigates improved air gap cavities for use in MEMS packaging processes, resulting in fewer fabrication flaws and lower cost. The identification of new materials, such as novel photo-definable organic/inorganic hybrid polymers, was studied for increased strength and rigidity due to their glass-like structure. A novel epoxy polyhedral oligomeric silsesquioxane (POSS) material was investigated and characterized for use as a photodefineable, permanent dielectrics with improved mechanical properties. The POSS material improved the air gap fabrication because it served as a high-selectivity etch mask for patterning sacrificial materials as well as a cavity overcoat material with improved rigidity. An investigation of overcoat thickness and decomposition kinetics provided a fundamental understanding of the properties that impart mechanical stability to cavities of different shape and volume. Metallization of the cavities was investigated so as to provide hermetic sealing and improved cavity strength. The improved air cavity, wafer-level packages were tested using resonator-type devices and chip-level lead frame packaging. The air cavity package was molded under traditional lead frame molding pressures and tested for mechanical integrity. The development of mechanical models complimented the experimental studies. A model of the overcoat materials used the film properties and elastic deformations to study the stress-strain behavior of the suspended dielectric films under external forces. The experimental molding tests and mechanical models were used to establish processing conditions and physical designs for the cavities as a function of cavity size. A novel, metal-free chip package was investigated combining the in-situ thermal decomposition of the sacrificial material during post-mold curing of the lead frame molding compound. Sacrificial materials were characterized for their degree of decomposition during the molding cure to provide a chip package with improved mechanical support and no size restrictions. Improvements to the air cavities for MEMS packaging led to investigations and refinements of other microfabrication processes. The sacrificial polycarbonate materials were shown to be useful as temporary bonding materials for wafer-level bonding. The release temperature and conditions of the processed wafer can be changed based on the polycarbonates formulation. The electroless deposition of metal was investigated as an alternative process for metalizing the air cavities. The deposition of silver and copper using a Sn/Ag catalyst as a replacement for costly palladium activation was demonstrated. The electroless deposition was tested on polymer and silicon dioxide surfaces for organic boards and through-silicon vias.

Fritz, Nathan T.

197

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

SciTech Connect

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

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

1998-11-01

198

Test model designs for advanced refractory ceramic materials  

NASA Technical Reports Server (NTRS)

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.

Tran, Huy Kim

1993-01-01

199

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

Code of Federal Regulations, 2010 CFR

...supervision of materials, design, and building. 401.5 Section 401.5 ...supervision of materials, design, and building. The Commission controls the design and prescribes regulations for the building of all memorial monuments and...

2010-07-01

200

14 CFR 23.613 - Material strength properties and design values.  

Code of Federal Regulations, 2013 CFR

...Material strength properties and design values. 23.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction § 23.613...Material strength properties and design values. (a)...

2013-01-01

201

14 CFR 23.613 - Material strength properties and design values.  

Code of Federal Regulations, 2012 CFR

...Material strength properties and design values. 23.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction § 23.613...Material strength properties and design values. (a)...

2012-01-01

202

14 CFR 23.613 - Material strength properties and design values.  

...Material strength properties and design values. 23.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction § 23.613...Material strength properties and design values. (a)...

2014-01-01

203

14 CFR 23.613 - Material strength properties and design values.  

Code of Federal Regulations, 2011 CFR

...Material strength properties and design values. 23.613 Section...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction § 23.613...Material strength properties and design values. (a)...

2011-01-01

204

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

NASA Technical Reports Server (NTRS)

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.

1974-01-01

205

Testing and design life analysis of polyurea liner materials  

NASA Astrophysics Data System (ADS)

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

Ghasemi Motlagh, Siavash

206

Design of materials configurations for enhanced phononic and electronic properties  

NASA Astrophysics Data System (ADS)

The discovery of novel nonlinear dynamic and electronic phenomena is presented for the specific cases of granular materials and carbon nanotubes. This research was conducted for designing and constructing optimized macro-, micro- and nano-scale structural configurations of materials, and for studying their phononic and electronic behavior. Variation of composite arrangements of granular elements with different elastic properties in a linear chain-of-sphere, Y-junction or 3-D configurations led to a variety of novel phononic phenomena and interesting physical properties, which can be potentially useful for security, communications, mechanical and biomedical engineering applications. Mechanical and electronic properties of carbon nanotubes with different atomic arrangements and microstructures were also investigated. Electronic properties of Y-junction configured carbon nanotubes exhibit an exciting transistor switch behavior which is not seen in linear configuration nanotubes. Strongly nonlinear materials were designed and fabricated using novel and innovative concepts. Due to their unique strongly nonlinear and anisotropic nature, novel wave phenomena have been discovered. Specifically, violations of Snell's law were detected and a new mechanism of wave interaction with interfaces between NTPCs (Nonlinear Tunable Phononic Crystals) was established. Polymer-based systems were tested for the first time, and the tunability of the solitary waves speed was demonstrated. New materials with transformed signal propagation speed in the manageable range of 10-100 m/s and signal amplitude typical for audible speech have been developed. The enhancing of the mitigation of solitary and shock waves in 1-D chains were demonstrated and a new protective medium was designed for practical applications. 1-D, 2-D and 3-D strongly nonlinear system have been investigated providing a broad impact on the whole area of strongly nonlinear wave dynamics and creating experimental basis for new theories and models. Potential applications include (1) designing of a sound scrambler/decoder for secure voice communications, (2) improving invisibility of submarine to acoustic detection signal, (3) noise and shock wave mitigation for protection of vibration sensitive devices such as head mounted vision devices, (4) drastic compression of acoustic signals into centimeter regime impulses for artificial ear implants, hearing aid and devices for ease of conversion to electronic signals and processing, and acoustic delay lines for communication applications.

Daraio, Chiara

207

Taguchi method of experimental design in materials education  

NASA Technical Reports Server (NTRS)

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.

Weiser, Martin W.

1993-01-01

208

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

PubMed

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

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

2014-06-21

209

Activating efficient phosphorescence from purely organic materials by crystal design  

NASA Astrophysics Data System (ADS)

Phosphorescence is among the many functional features that, in practice, divide pure organic compounds from organometallics and inorganics. Considered to be practically non-phosphorescent, purely organic compounds (metal-free) are very rarely explored as emitters in phosphor applications, despite the emerging demand in this field. To defy this paradigm, we describe novel design principles to create purely organic materials demonstrating phosphorescence that can be turned on by incorporating halogen bonding into their crystals. By designing chromophores to contain triplet-producing aromatic aldehydes and triplet-promoting bromine, crystal-state halogen bonding can be made to direct the heavy atom effect to produce surprisingly efficient solid-state phosphorescence. When this chromophore is diluted into the crystal of a bi-halogenated, non-carbonyl analogue, ambient phosphorescent quantum yields reach 55%. Here, using this design, a series of pure organic phosphors are colour-tuned to emit blue, green, yellow and orange. From this initial discovery, a directed heavy atom design principle is demonstrated that will allow for the development of bright and practical purely organic phosphors.

Bolton, Onas; Lee, Kangwon; Kim, Hyong-Jun; Lin, Kevin Y.; Kim, Jinsang

2011-03-01

210

Induced multiferroics: and materials  

E-print Network

of high-frequency impedance � e.g. software- defined radio Negative index of refraction for rf antennae per function reduction) and performance (speed, power) and reliability values to the applications-geometrical process techniques and new materials that affect the electrical performance of the chip 2. Functional

Natelson, Douglas

211

Materials Design for Joinable, High Performance Aluminum Alloys  

NASA Astrophysics Data System (ADS)

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

Glamm, Ryan James

212

Designing intermediate-range order in amorphous materials.  

PubMed

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

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

2002-09-26

213

665: Building Material Selection and Air Quality in Healthcare Design: A Survey of the Design and Construction Industry  

Microsoft Academic Search

The decisions architects make over the selection of materials for interior spaces is crucial in the hospital setting. The depth of understanding the properties of the material influences these decisions. Design parameters include functionality, aesthetics, availability and cost, in addition to economic and social concerns, particularly when designing sustainable buildings. Common materials selected for interiors emit volatile organic compounds (VOCs),

Kelly Cook; Pamela Harght; Jae Chang

214

Ab initio materials design for transparent-conducting-oxide-based new-functional materials  

Microsoft Academic Search

Based upon ab initio electronic structure calculations for delafossite CuAlO2 and ZnO, we report on the design of new-functional materials for transparent conducting oxides (TCO), such as (i) low-resistive\\u000a p-type ZnO and CuAlO2 by co-doping, (ii) high-efficiency thermoelectric power in CuAlO2 (ZT>3) by p-type doping, (iii) half-metallic ferromagnetism in transition-metal-impurity doped CuAlO2 and ZnO-based diluted magnetic semiconductors, and (iv) CaO,

H. Katayama-Yoshida; K. Sato; H. Kizaki; H. Funashima; I. Hamada; T. Fukushima; V. A. Dinh; M. Toyoda

2007-01-01

215

Materials Design based on Predictive Ab Initio Thermodynamics  

NASA Astrophysics Data System (ADS)

A key requirement in developing predictive multi-scale modeling is the availability of accurate computational tools determining energies not only at T = 0 K but also under realistic conditions, i.e., at finite temperature. Combining accurate first principles calculations with mesoscopic/macroscopic thermodynamic and/or kinetic concepts allows now to address this issue and to determine free energies and derived thermodynamic quantities such as heat capacity, thermal expansion coefficients, and elastic constants with an accuracy that matches and often even rivals available experimental data. In the talk a brief overview of the fundamentals and recent developments of combining modern fully parameter-free ab initio methods with thermodynamic concepts will be given with special emphasize on structural materials. The flexibility and the predictive power of these approaches and the impact they can have in developing new strategies in materials design will be discussed e.g. for modern high strength TWIP/TRIP steels, for understanding failure mechanisms such as hydrogen embrittlement, or for identifying chemical trends in the performance of light weight metallic alloys. Work has been done in collaboration with Fritz Kormann, Blazej Grabowski, and Tilmann Hickel.

Neugebauer, Joerg

2013-03-01

216

Designing functionally graded materials with superior load-bearing properties.  

PubMed

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 guidelines for designing FGMs 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 (E(b)/E(s)) on stress distribution through the graded layer. Theory predicts that a low exponent (0.15materials with various n values and E(b)/E(s) 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, 20-50% 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

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

2012-03-01

217

advancing sustainable Interaction Design: two perspectives on material effects design philosophy papers #04 / 2006 ISSN 1448-7136  

E-print Network

advancing sustainable Interaction Design: two perspectives on material effects Eli Blevis design SUSTAINABLE INTERACTION DESIGN: TWO PERSPECTIVES ON MATERIAL EFFECTS Eli Blevis School of Informatics Indiana) Conference on Human Factors in Computing Systems, CHI 2007. The conference paper title is "Sustainable

Blevis, Eli

218

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

E-print Network

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 ...

Gonzalez Uribe, Carlos David

2014-01-01

219

Design of semi-active variable impedance materials using field-responsive fluids  

E-print Network

In this thesis, I explored the design of a thin variable impedance material using electrorheological (ER) fluid that is intended to be worn by humans. To determine the critical design parameters of this material, the shear ...

Eastman, Douglas Elmer

2004-01-01

220

Innovation and sustainability in mechanical design through materials selection  

Microsoft Academic Search

Materials selection is a difficult and subtle task, due to the immense number of different available materials. Dealing with such exhaustive information was made possible through the systematization of the materials by their properties. Systematization provides enlarging the classical list of materials and offers new possibilities, facing innovation and sustainability.A practical example concerning the selection of materials to substitute poly

M. J. Matos; M. H. Simplício

2006-01-01

221

Multiscale materials design of natural exoskeletons : fish armor  

E-print Network

Biological materials have developed hierarchical and heterogeneous material nanostructures and microstructures to provide protection against various environmental threats that, in turn, provide bioinspired clues to man-made, ...

Song, Juha

2011-01-01

222

Design and evaluation of digital activating learning materials for Food Chemistry education  

Microsoft Academic Search

The research described in this thesis is a design oriented research that aims at designing and developing activating digital learning materials for food chemistry education. It is expected that digital activating learning materials will provide an efficient and motivating situation for both teachers and students. The learning materials described in this thesis were designed and developed with the help of

J. Diederen

2005-01-01

223

Design of digital learning material for bioprocess-engineering-education  

Microsoft Academic Search

With the advance of computers and the internet, new types of learning material can be developed: web-based digital learning material. Because many complex learning objectives in the food- and bioprocess technology domain are difficult to achieve in a traditional learning environment, a project was started to explore the possibilities of digital learning material to address those learning objectives. The material

Schaaf van der H

2007-01-01

224

Optical metamaterials: Design, simulation and feedback from experimental characterization  

NASA Astrophysics Data System (ADS)

Artificially structured materials (metamaterials) demonstrating negative index of refraction have opened an entire area of research. Metamaterials are not limited to just negative index metamaterials, but could be extended to artificial magnetism, chirality, etc. Such materials extend the material properties, to beyond what is available in nature. This enables us to control and manipulate light in an unprecedented manner and creates an immense potential for applications. In this work, simulations tools were developed for the study and design of metamaterials. These tools were based on 3D Finite Difference Time Domain (FDTD) method and Spatial Harmonic Analysis (SHA). In addition to this, a commercial tool based on Finite Element Method was also used. The first negative index material at the optical range was demonstrated, which showed a refractive index of around --0.3 at the telecom wavelength of 1.5 mum. This was followed by the demonstration of a double negative material at the lowest wavelength till date. It showed a refractive index of --0.8 at a wavelength of 725 nm. The negative index material at the shortest wavelength was demonstrated at a wavelength of 710nm. It showed a refractive index of --0.6 at a wavelength of 710 nm. Structures with artificial negative magnetism were also demonstrated across the entire visible range up to a wavelength of 490 nm. Rigorous study was performed on the effect of roughness and size effects on the performance of the nanoscale structures that were used in the metamaterial prototypes. It was concluded that roughness decreases the quality factor of the resonances that are vital for the novel properties. Roughness affects only parts of the spectrum that are close to a resonance. The size effect increases the losses in the metal that makes up the structure and consequently decreases the quality factor of the resonances. Unlike roughness, the size effect does not show a wavelength dependence based on resonances. The parallel 3D FDTD solver was used to numerically study the local field response in semicontinuous metal films (SMFs). These solutions provide insight into the nature of the local field enhancements in SMFs.

Chettiar, Uday Krishnaswamy

225

Design and characterization of novel ?-cyclodextrin based copolymer materials.  

PubMed

Reported herein are the systematic design and characterization of several novel polyurethane (PU) copolymers containing a macrocyclic porogen (?-cyclodextrin; ?-CD). These copolymers were synthesized from the reaction between ?-CD with different types of diisocyanate linker molecules (e.g., 1,6-hexamethylene diisocyanate (HDI), 4,4'-dicyclohexylmethane diisocyanate (CDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,4-phenylene diisocyanate (PDI) and 1,5-naphthalene diisocyanate (NDI)) at variable synthetic conditions. The copolymers were characterized using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), solid state (13)C CP-MAS NMR, (1)H/(13)C solution NMR spectroscopy, thermogravimetric analysis (TGA) and elemental analyses (CHN). The PU copolymers were generally insoluble in water and the optimal preparation of copolymer materials for sorption-based applications is for ?-CD/linker synthetic mole ratios from 1:1 to 1:3. The practical upper limit of the crosslink density (approximately 1:7, ?-CD/linker) depends on the steric bulk of the cross linker units. PMID:21172695

Mohamed, Mohamed H; Wilson, Lee D; Headley, John V

2011-02-01

226

Materials design of substrates for gas adsorption and storage  

NASA Astrophysics Data System (ADS)

All the three chapters in the thesis are originated from the efforts of hydrogen storage, although the metal stabilization can be beyond that. It is well known that hydrogen storage is the bottleneck problem of a grand hydrogen economy, but its notorious low volumetric density creates an overwhelming challenge in storage. Materials-based storage might make it possible to store large quantities of hydrogen in small volume at practical temperature and pressure. However, the actual experiments are hard to perform and even to explain the results, which gives computer simulations a big chance to investigate the storage. In this thesis, I use the Density Functional Theory based software to explore the new materials. A brief introduction of DFT theoretical background is given in the first chapter. In Chapter 2, we study how to prevent the metal atoms from aggregating. In nature, low-coordinated metal atoms can provide new opportunities for gas storage and catalysis when they are exposed to their environment. But unfortunately, they are generally unstable against aggregation. We demonstrate that electron deficiency in an sp2 carbon layer, induced by heavy (but realistic) boron doping, can stabilize sparse metal layers (Be, Mg, Sc and Ti) against aggregation thermodynamically. If the atomically dispersed metals are not thermodynamically favored, take Pd as an example, local inhomogeneities in boron density will create large kinetic barriers against aggregation, so Pd layer can be kinetically stable. In Chapter 3, we first introduce the two new classes of materials. The compelling Ammonia Boron based materials used for chemical storage attract interests because of their high hydrogen content, but the overly stable products seriously eliminate any possibility of reversible storage. On the other hand, the organic frameworks exhibit strong structural stability and accessibility. Almost all of the atoms are on the surface. These amazing properties look like exclusively being tailored for the hydrogen release in one of the products, PAB polymer. We combine the advantages of the polymer and framework, then design four series of frame-works. They are proven stable through molecular dynamics simulations. Chapter 4 is focused on the essential issue of hydrogen applications: the release kinetics. We present a novel idea to tune the activation barrier by coupling the polymer with an external framework spring, and then apply it to the simple PAB -- PAB/H2 transformation. Our results for planar polymer transformations show that this coupling indeed change both the hydrogen binding energy EB and its release barrier DeltaEK, although the lowest barrier by this tuning is still too large. When the polymer is compressed, the EB and DeltaEK are lowered; when the polymer is stretched, the EB and DeltaEK are raised. Finally, we test a non-planar transformation and achieve a great improvement in DeltaEK, so the non-planar polymer transformation might be an much more effective way in hydrogen release.

Huang, Zhaohui

227

FireWise Construction: Site Design & Building Materials  

E-print Network

for Testing and Materials (ASTM) committees that develop standards on the performance of materials in fire with the Pike Hot Shots in 1977. He then worked for the Bureau of Land Management as a West Zone Fire Management

228

Fab trees for designing complex 3D printable materials  

E-print Network

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 ...

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

2013-01-01

229

Design and evaluation of lost circulation materials for severe environments  

SciTech Connect

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

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

1988-01-01

230

A demonstration of simple airfoils: Structural design and materials choices  

SciTech Connect

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

Bunnell, L.R. (Pacific Northwest Lab., Richland, WA (United States)); Piippo, S.W. (Richland School District, WA (United States))

1993-01-01

231

A spine layout design method for semiconductor fabrication facilities containing automated material-handling systems  

Microsoft Academic Search

A bay configuration arranged along a central spine and served by an automated monorail material-handling system are common designs for the layout and material-handling system in new semiconductor wafer fabrication facilities. Investigates the facility design problem in semiconductor fabrication facilities and proposes a procedure to determine the optimal spine layout design, given a design of the material-handling system. Explains and

Taho Yang; Brett A. Peters

1997-01-01

232

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

SciTech Connect

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

Hilton, Harry H. [Aerospace Engineering Department, Technology Research, Education and Commercialization Center, National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, 104 South Wright Street, MC-236 Urbana, IL 61801-2935 (United States)

2008-02-15

233

A study of learning performance of e-learning materials design with knowledge maps  

E-print Network

1 1 A study of learning performance of e-learning materials design with knowledge maps (Ruey Journal Articles (2006-2009) 1. R. S. Shaw, "A study of learning performance of e-learning materials "Information Security Awareness to "e-Learning Materials Design " 44 The Integrated Framework of Information

Ouhyoung, Ming

234

Design of materials with extreme thermal expansion using a three-phase topology optimization method  

Microsoft Academic Search

We show how composites with extremal or unusual thermal expansion coefficients can be designed using a numerical topology optimization method. The composites are composed of two different material phases and void. The optimization method is illustrated by designing materials having maximum thermal expansion, zero thermal expansion, and negative thermal expansion. Assuming linear elasticity, it is shown that materials with effective

Ole Sigmund; Salvatore Torquato

1997-01-01

235

Integrated Facility Layout And Material Handling System Design In Semiconductor Fabrication Facilities  

Microsoft Academic Search

Semiconductor manufacturing is an important component of the US manufacturing industry. Most oftoday's fabrication facilities and those being designed for the near future use a bay layout configuration andan overhead monorail system for moving material between bays. These material handling systems areusually designed with a spine or perimeter type of configuration. This paper investigates the layout andmaterial handling system design

Brett A. Peters; Taho Yang

1995-01-01

236

Optimal shape design as a material distribution problem  

Microsoft Academic Search

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

M. P. Bendsøe

1989-01-01

237

46 CFR 160.077-7 - Procedure for approval of design or material revision.  

Code of Federal Regulations, 2011 CFR

...HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING EQUIPMENT Hybrid Inflatable Personal Flotation Devices § 160.077-7 Procedure for approval of design or material revision....

2011-10-01

238

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. ...

239

Design of Geopolymeric Materials Based on Nanostructural Characterization and Modeling.  

National Technical Information Service (NTIS)

Geopolymers, a class of largely X-ray amorphous aluminosilicate binder materials, have been studied extensively over the past several decades, but largely from an empirical standpoint. The primary aim of this investigation has been to apply a more science...

G. C. Lukey, J. S. van Deventer, J. L. Provis, P. Duxson

2006-01-01

240

Design of novel lithium storage materials with a polyanionic framework  

E-print Network

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 ...

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

2014-01-01

241

Thermoelectric materials evaluation program spring design to minimize load relaxation  

SciTech Connect

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)

Grimm, F.R.

1980-03-31

242

Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth.  

PubMed

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

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

2014-05-15

243

30 CFR 18.20 - Quality of material, workmanship, and design.  

Code of Federal Regulations, 2010 CFR

...for its intended use. Since all possible designs, circuits, arrangements, or combinations of components and materials cannot be foreseen, MSHA reserves the right to modify design, construction, and test requirements to obtain the same...

2010-07-01

244

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

Code of Federal Regulations, 2010 CFR

...and is safe for its intended use. Since all possible designs, arrangements, or combinations of components and materials cannot be foreseen, MSHA reserves the right to modify the construction and design requirements of subassemblies or...

2010-07-01

245

Application of interactive design as teaching materials for learning disabled students  

Microsoft Academic Search

This study focuses on how to design teaching materials for learning disabled students. User-friendly and user-centred interface design are the basic rules. In this study, we understand different needs from different learning disabled students, then design and made customer-made teaching materials, it is discussed to explicate why the design worked well and how it can be improved on different case

Chien-Yu Lin; Chih-feng Lee; E. Chang; Jie-Ying Chen; Rain Chen; Yin-Yin Chang; Kai-Ping Yang

2010-01-01

246

New Materials Design Through Friction Stir Processing Techniques  

SciTech Connect

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

Buffa, G.; Fratini, L. [Dipartimento di Tecnologia Meccanica, Produzione e Ingegneria Gestionale, Universita di Palermo, Viale delle Scienze 90128 Palermo (Italy); Shivpuri, R. [Ohio State University, Department of Industrial, Welding and Systems Engineering, 1971 Neil Avenue, 210 Baker Systems, Columbus, Ohio 43210 (United States)

2007-04-07

247

Automated Design of MultiStage Molds for Manufacturing Multi-Material Objects  

Microsoft Academic Search

This paper describes a geometric algorithm for automated design of multi-stage molds for manufacturing multi-material objects. In multi-stage molding process, the desired multi-material object is produced by carrying out multiple molding operations in a sequence, adding one material in the target object in each mold-stage. We model multi-material objects as an assembly of single-material components. Each mold-stage can add only

Malay Kumar; Satyandra K. Gupta

2002-01-01

248

Design of a scientific probe for obtaining Mars surface material  

NASA Technical Reports Server (NTRS)

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.

1990-01-01

249

NANOSTRUCTURED MATERIAL DESIGN FOR HG, AS, AND SE CAPTURE  

EPA Science Inventory

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

250

The Empirical Attitude, Material Practice and Design Activities  

ERIC Educational Resources Information Center

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

Apedoe, Xornam; Ford, Michael

2010-01-01

251

Sustainable design and environmental impact of materials in sports products  

Microsoft Academic Search

New sports product innovations are rapidly developed and brought to market by the manufacturers in order to accommodate the diverse needs and changing personal preferences of the users. Over the years, this has resulted in a shorter life cycle of sports products and increased disposal rates and waste. Also, advances based on the use of new processes and high?performance materials

Aleksandar Subie; Adrian Mouritz; Olga Troynikov

2009-01-01

252

Photovoltaic module encapsulation design and materials section, volume 2  

NASA Technical Reports Server (NTRS)

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.

Cuddihy, E. F.

1984-01-01

253

Nonstoichiometric Laser Materials: Designer Wavelengths in Neodymium Doped Garnets  

NASA Technical Reports Server (NTRS)

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

Walsh, Brian M.; Barnes, Norman P.

2008-01-01

254

Recycling of plastic material in design world: examples from automotive industry  

Microsoft Academic Search

In this study, plastic materials recycling, which has the environmental and economic values, discussion with studies and design applications especially automotive industry are included. Pollution of sources and recycling of scrap materials are the two strong reasons for recycling concept. The designers, consumers, producers and governments are constrained to comprehend recycling subject because of the fact of increasing on consumption

Ceyda Vatan

255

Application of chiral cellular materials for the design of innovative components  

Microsoft Academic Search

Low-density cellular solids have demonstrated superior mechanical properties as well as multifunctional characteristics, which may provide a basis for the development of novel structured materials. In particular, cellular solids offer great design flexibility, owing to their topology, which can provide desired functionalities via targeted geometric design and proper selection of the constituent material. While stochastic configurations such as metallic foams

Alessandro Spadoni

2008-01-01

256

Exascale Co-Design Center for Materials In Extreme Environments  

E-print Network

physics refinement. · Our vision is an uncertainty quantification (UQ) driven adaptive physics refinement and weather prediction, structural engineering, plasma physics, and radiation hydrodynamics. One of Three DOE/SC/ASCR Co-Design Centers App SW M iddlew are Sim ulators, PrototypesHW Domain workload Functional Exascale

257

MULTI-SCALE COMPUTATIONAL TECHNIQUES FOR DESIGN OF POLYCRYSTALLINE MATERIALS  

E-print Network

properties in the component. By carefully designing the imposed deformation, one could poten- tially tailor. The techniques presented are an interplay of several new tools developed recently, such as reduced order modeling. #12;BIOGRAPHICAL SKETCH The author was born in Chennai, formerly Madras, India in September 1981

Zabaras, Nicholas J.

258

Design of a scientific probe for obtaining Mars surface material  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

259

Biochemically designed polymers as self-organized materials  

NASA Astrophysics Data System (ADS)

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

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

1997-02-01

260

Packaging Materials and Design for Improved PV Module Reliability  

SciTech Connect

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.

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

2005-01-01

261

Layered zeolitic materials: an approach to designing versatile functional solids.  

PubMed

Relevant layered zeolites have been considered in this perspective article from the point of view of the synthesis methodologies, materials characterization and catalytic implications, considering the unique physico-chemical characteristics of lamellar materials. The potential of layered zeolitic precursors to generate novel lamellar accessible zeolites through swelling, intercalation, pillarization, delamination and/or exfoliation treatments is studied, showing the chemical, functional and structural versatility exhibited by layered zeolites. Recent approaches based on the assembly of zeolitic nanosheets which act as inorganic structural units through the use of dual structural directing agents, the selective modification of germanosilicates and the direct generation of lamellar hybrid organic-inorganic aluminosilicates are also considered to obtain layered solids with well-defined functionalities. The catalytic applications of the layered zeolites are also highlighted, pointing out the high accessibility and reactivity of active sites present in the lamellar framework. PMID:24457617

Díaz, Urbano; Corma, Avelino

2014-07-21

262

Nonlinear Optical Polymeric Materials: From Chromophore Design to Commercial Applications  

Microsoft Academic Search

Polymeric electro-optic materials have recently been developed that, when fabricated into devices such as Mach-Zehnder interferometers,\\u000a permit drive ( V?) voltages of less than 1 V to be realized at the telecommunications wavelength of 1.3 and 1.55 microns. Operation of polymeric\\u000a electro-optic modulators to frequencies (bandwidths) of greater than 100 GHz has been demonstrated. The total insertion loss\\u000a of polymeric

Larry Dalton

263

Road Materials and Pavements Design. Volume X No X/2009, pages 1 to 16 Pavement Design for Curved Road Sections  

E-print Network

Road Materials and Pavements Design. Volume X ­ No X/2009, pages 1 to 16 Pavement Design for Curved pavements Christophe Petit* -- Malick Diakhaté* -- Anne Millien* -- Annabelle Phelipot-Mardelé* -- Bertrand@eurovia.com ABSTRACT. This paper focuses on damage processes other than the main one observed and studied in pavement

Paris-Sud XI, Université de

264

Virtual Welded - Joint Design Integrating Advanced Materials and Processing Technology  

SciTech Connect

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

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

2005-06-30

265

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 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...

2010-10-01

266

Above Ground Geothermal and Allied Technologies Masters Scholarship in Energy & Materials: design of a rig  

E-print Network

of a rig to test materials for Organic Rankine Cycle powerplant Department of Mechanical Engineering, for their thesis research project, design a rig to test corrosion and scaling of sample materials. The rig the completed rig and obtain the first set of results. The rig will expose the materials to flows of different

Hickman, Mark

267

A PROTOTYPE OF KBS FOR MATERIAL SELECTION IN BUMPER BEAM DESIGN  

Microsoft Academic Search

This paper describes the development of the Knowledge Based System (KBS) for material selection in bumper beam design. The KBS is an expert system used to select the most suitable material by defining constraint values into the system. The aim of this project is to select the most suitable material for an automotive bumper beam. The selection method was based

Mohd Nizam Sudin; Mohd Ruzi Harun; Ahmad Tajudin Hamzah

2007-01-01

268

Impact of materials and design changes on the recycling of automobiles  

Microsoft Academic Search

Current and prospective changes in automotive materials and design will in time affect the recycling of discarded automobiles. These changes are already altering the pattern of materials consumption and process-scrap generation in terms of size reduction, the use of ferrous metals, aluminum, plastics and composites, as well as of some other materials that will be used in future automobiles. Likely

1980-01-01

269

A simple simulation method for designing fibrous insulation materials R. Arambakam a  

E-print Network

to predict thermal insulation properties in terms of SVF and thermal conductivity of solid and interstitialA simple simulation method for designing fibrous insulation materials R. Arambakam a , H. Vahedi: Conductive heat transfer Fibrous materials Insulation materials Numerical simulation a b s t r a c

Tafreshi, Hooman Vahedi

270

Optimized Design of Radar Absorbing Materials for Complex Targets  

Microsoft Academic Search

Abstract—In this paper, we present a hybrid technique for designing RAM optimally to reduce the RCS of complex targets in a wide-band frequency range. The technique combines a high-frequency method and a genetic algorithm (GA) to obtain an optimal RAM in complex targets. By the virtue of the high-frequency method, such as the physical optics (PO) method and the method,of

H.-S. Park; I.-S. Choi; J.-K. Bang; S.-H. Suk; S.-S. Lee; H.-T. Kim

2004-01-01

271

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

SciTech Connect

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.

Hosokawa, H.; Higashi, K.

2000-07-01

272

Computational design of new A2BX4 materials  

NASA Astrophysics Data System (ADS)

The A2BX4 family of ternary compounds represents an important class of materials. Members of this group, in addition to being among the earth most abundant materials, also span a significant range of physical properties including ferromagnetism, coexistence of transparency and p-type conductivity, ferroelectricity, etc. Today we know for about 800 A2BX4 compounds that have been characterized experimentally. This is only a portion of nearly 5000 A2BX4 combinations that could be constructed throughout the periodic table. In this talk I will present a systematic theoretical approach, based on ab initio calculations, for predicting new A2BX4 compounds. For a given new A2BX4 combination we find the candidate crystal structures from the classification of the existing A2BX4 in terms of the atomic orbital radii of the constituent A and B atoms (Zhang and Zunger, Adv. Funct. Mat. 20, 1944, 2010). This step is followed by the set of high-throughput ab initio calculations which are used to sort out the ground-state structure and compute the corresponding heat of formation. The stability of a given A2BX4 with respect to decomposition into competing phases is then tested against all possible combinations of known compounds involving the same elements. This is done by comparing the heat of formation of the new ternary and the heats of formation of the competing (existing) binary and ternary compounds. I will also discuss the algorithms for searching the chemical space of ternary compounds in order to find the materials with target properties.

Stevanovic, Vladan

2011-03-01

273

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

NASA Astrophysics Data System (ADS)

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.

Barthelat, Francois

2014-12-01

274

Decoupling interrelated parameters for designing high performance thermoelectric materials.  

PubMed

The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for synergistically enhanced thermoelectric properties. This occurs through a significant reduction of thermal conductivity, without the deterioration of thermopower and electrical conductivity. In addition, we introduce the concept of spin entropy in wide band gap semiconductor nanocrystals, which acts to fully disentangle the otherwise interconnected quantities for synergistically optimized thermoelectric performance. Finally, we discuss a new concept we developed that is based on an ultrathin-nanosheet composite that we fabricated from ultrathin nanosheets of atomic thickness. These retain the original strong two-dimensional electron gas (2DEG) and allow for decoupled optimization of the three thermoelectric parameters, which improves thermoelectric performance. PMID:24517646

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

2014-04-15

275

Negative index of refraction in optical metamaterials  

Microsoft Academic Search

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

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

2005-01-01

276

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

E-print Network

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 ...

Ceder, Gerbrand

277

Materials Design and Discovery with High-Throughput Density Functional Theory: The Open Quantum Materials Database (OQMD)  

NASA Astrophysics Data System (ADS)

High-throughput density functional theory (HT DFT) is fast becoming a powerful tool for accelerating materials design and discovery by the amassing tens and even hundreds of thousands of DFT calculations in large databases. Complex materials problems can be approached much more efficiently and broadly through the sheer quantity of structures and chemistries available in such databases. Our HT DFT database, the Open Quantum Materials Database (OQMD), contains over 200,000 DFT calculated crystal structures and will be freely available for public use at http://oqmd.org. In this review, we describe the OQMD and its use in five materials problems, spanning a wide range of applications and materials types: (I) Li-air battery combination catalyst/electrodes, (II) Li-ion battery anodes, (III) Li-ion battery cathode coatings reactive with HF, (IV) Mg-alloy long-period stacking ordered (LPSO) strengthening precipitates, and (V) training a machine learning model to predict new stable ternary compounds.

Saal, James E.; Kirklin, Scott; Aykol, Muratahan; Meredig, Bryce; Wolverton, C.

2013-11-01

278

Characterization, numerical analysis and design of switched reluctance motor for improved material productivity and reduced noise  

Microsoft Academic Search

The material productivity and design certainty are becoming ever more important for a responsive motor manufacturer, and they can be improved by design optimization through more detailed analysis and simulation within manufacturing tolerance, in particular for a large and unconventional motor. Design by analysis and simulation of a switched reluctance motor is the subject of this paper, with numerical approaches

Yifan Tang

1996-01-01

279

Comparison of gap frame designs and materials for precision cathode strip chambers  

SciTech Connect

Precision cathode strip chamber perimeter designs that incorporate either continuous or discrete-post gap frames are analyzed. The effects of ten design and material combinations on gravity sag, mass, stress, and deflected shape are evaluated. Procedures are recommended for minimizing mass in the chamber perimeter region while retaining structural integrity and electrical design latitude.

Horvath, J.A.; Pratuch, S.M.; Belser, F.C. [Lawrence Livermore National Lab., CA (United States)

1993-09-16

280

Ionomer Design Principles for Single Ion-Conducting Energy Materials  

NASA Astrophysics Data System (ADS)

Single-ion conducting ionomers with low glass transition temperature, high dielectric constant and containing bulky ions with diffuse charge, are needed for polymer membranes that transport small counterions. Overarching design principles emerging from quantum chemistry calculations suggest that diffuse charge can be attained from simple considerations of atomic electronegativity. For lithium or sodium batteries, perfluorinated tetraphenyl borate ionomers with solvating polar comonomers are proposed. For fluoride or hydroxide batteries and for iodide transporting solar cells, tetra-alkyl phosphonium ionomers with anion receptors are proposed. First attempts to construct such ionomers to test these ideas will be discussed, with results from dielectric spectroscopy to measure conductivity, dielectric constant and number density of simultaneously conducting ions.

Colby, Ralph; Liang, Siwei; Liu, Wenjuan; Hyeok Choi, U.; Runt, James; Shiau, Huai-Suen; Janik, Michael

2012-02-01

281

Dedication to Degradation: The Beauty of Materials Designed to Lay in Ruin  

NASA Astrophysics Data System (ADS)

Degradation of materials is typically perceived to be a negative response in service. Many designs, and materials, have been and are ruined due to corrosion, fatigue, weathering, ultraviolet light, fungal attack, bacterial attack, erosion, wear, electromigration… and on the list goes. However, the carefully controlled and purposeful degradation of materials is a prerequisite for success for some designs—and such ability is a beautiful necessity when it comes to many regenerative biomaterials. In other instances, we must seek first to understand the degradation mechanisms before we can achieve degradation prevention—and the resistance of some materials to degradation is also beautiful. Regardless of whether we try to prevent or elicit degradation, our dedication to degradation of materials is ever present in materials design.

Nychka, John A.; Kruzic, Jaime

2014-04-01

282

Design and synthesis of inorganic/organic hybrid electrochemical materials  

NASA Astrophysics Data System (ADS)

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.

Harreld, John H.

283

Life Modeling and Design Analysis for Ceramic Matrix Composite Materials  

NASA Technical Reports Server (NTRS)

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.

2005-01-01

284

Ranking the stars: a refined Pareto approach to computational materials design.  

PubMed

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

Lejaeghere, Kurt; Cottenier, Stefaan; Van Speybroeck, Veronique

2013-08-16

285

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

E-print Network

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 ...

Kwan, Joyce G

2013-01-01

286

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

...Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS METHANE-MONITORING SYSTEMS Construction and Design Requirements § 27.20 Quality of material, workmanship, and...

2014-07-01

287

Achieving High Performance Polymer Tandem Solar Cells via Novel Materials Design.  

E-print Network

??Organic photovoltaic (OPV) devices show great promise in low-cost, flexible, lightweight, and large-area energy-generation applications. Nonetheless, most of the materials designed today always suffer from… (more)

Dou, Letian

2014-01-01

288

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

SciTech Connect

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.

Ren, Weiju [ORNL

2008-01-01

289

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

Microsoft Academic Search

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

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

2007-01-01

290

Curriculum Design for Inquiry: Preservice Elementary Teachers' Mobilization and Adaptation of Science Curriculum Materials  

ERIC Educational Resources Information Center

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…

Forbes, Cory T.; Davis, Elizabeth A.

2010-01-01

291

Brittle materials design, high temperature gas turbine. Interior report no. 11, 1 Jul31 Dec 76  

Microsoft Academic Search

The demonstration of uncooled brittle materials in structural applications at 2500 F is the objective of the 'Brittle Materials Design, High Temperature Gas Turbine' program. Ford Motor Company, the contractor, is utilizing a small vehicular gas turbine comprising an entire ceramic hot flow path including the highly stressed turbine rotors. Westinghouse, the subcontractor, originally planned to evaluate ceramic first stage

A. F. McLean; E. A. Fisher

1977-01-01

292

EIND 442 FACILITY AND MATERIAL HANDLING SYSTEM DESIGN Instructor: William Schell, PhD, PE  

E-print Network

production facilities and material handling systems. Product and process analysis, requirements, layout.edu/policy/studentconduct Objectives: Address fundamental concepts and tools in three areas: facility layout, material handling systems engineering design tools, 3. Identify different types of facility layout problems and apply existing

Dyer, Bill

293

Evaluating and Designing Language Teaching Materials. Practical Papers in English Language Education, Volume 2.  

ERIC Educational Resources Information Center

This article offers teachers a comprehensive set of questions to ask themselves in evaluating their instructional materials and offers proposals for the adaptation and design of materials. These suggestions are postulated on a definition of language as communication and language teaching as a communicative process. The following are discussed: (1)…

Candlin, Christopher N.; Breen, Michael P.

294

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Hydraulic or pneumatic power and control-materials and pressure...Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials and pressure...and standard valves) for hydraulic or pneumatic power and control systems must...

2013-10-01

295

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Hydraulic or pneumatic power and control-materials and pressure...Pressure Design § 128.240 Hydraulic or pneumatic power and control—materials and pressure...and standard valves) for hydraulic or pneumatic power and control systems must...

2012-10-01

296

Designing Gelatin Based Blood Compatible Materials with Hydrophilic and Hydrophobic Macromolecular Chains  

Microsoft Academic Search

Polymer matrices based on poly 2-hydroxyethyl methacrylate (PHEMA) have emerged as promising materials for developing applications in biomedical and tissue engineering fields. The major criteria of a material to be used as a support matrix in tissue engineering application rests on its biocompatible, hydrophilic, and mechanically strong nature. Although a great deal of research efforts have been put into designing

A. K. Bajpai; Sanjana Kankane; Sunil K. Singh

2011-01-01

297

Presented at 1999 EWEC Effects of Materials Parameters and Design Details on the Fatigue of  

E-print Network

Presented at 1999 EWEC Effects of Materials Parameters and Design Details on the Fatigue@sandia.gov ABSTRACT: This paper presents an analysis of the results of nine years of fatigue testing represented in the U.S. Department of Energy / Montana State University (DOE/MSU) Composite Materials Fatigue Database

298

Design of materials with extreme thermal expansion using a three-phase topology optimization method  

Microsoft Academic Search

Composites with extremal or unusual thermal expansion coefficients are designed using a three-phase topology optimization method. The composites are made of two different material phases and a void phase. The topology optimization method consists in finding the distribution of material phases that optimizes an objective function (e.g. thermoelastic properties) subject to certain constraints, such as elastic symmetry or volume fractions

O. Sigmund; S. Torquato

1997-01-01

299

An Annotated Bibliography of Materials Designed and Organized for Adult Use in Discussion Groups.  

ERIC Educational Resources Information Center

This first annotated bibliography of materials designed and organized for adult use in disucssion groups includes both book and nonbook material. Areas dealt with are: art, censorship, change, child guidance, communication, crime, democracy, economics, education, evolution, food, foreign affairs, forgetting, generation gap, gold, good and evil,…

Ellison, John W.

300

Design and fabrication of narrow band radar absorbing materials at terahertz frequencies  

Microsoft Academic Search

The technique of tailoring the complex refractive index of an artificial dielectric material has been developed at the University of Lowell Research Foundation (ULRF). Low reflection coatings, generally referred to as Dällenbach layers, have been designed for metal substrates using the artificial dielectric. The method of characterizing materials for the purpose of tailoring their dielectric properties at terahertz frequencies will

R. H. Giles; A. J. Gatesman; A. P. Ferdinand; J. Waldman

1990-01-01

301

A data mining approach to forming generic bills of materials in support of variant design activities  

E-print Network

1 A data mining approach to forming generic bills of materials in support of variant design. This research presents a novel, data mining approach to forming generic bills of materials (GBOMs), entities through data mining methods such as text and tree mining, a new tree union procedure, and embodying

Nagi, Rakesh

302

Design and selection of materialized views in a data warehousing environment: a case study  

Microsoft Academic Search

In this paper, we describe the design of a data warehousing system for an engineering company 'R'. A cost model was developed for this system to enable the evaluation of the total costs and benefits involved in selecting each materialized view. Using the cost analysis methodology for evaluation, an adapted greedy algorithm has been implemented for the selection of materialized

Goretti K. Y. Chan; Qing Li; Ling Feng

1999-01-01

303

Designing Hydrogels for Biomedical Applications Hydrogels represent a unique class of materials with wide spread application.  

E-print Network

. These copolymers are built on the same architectural designs as the ABA systems; however, one block is changed fromDesigning Hydrogels for Biomedical Applications Hydrogels represent a unique class of materials than 10,000 Pascals from a class of biocompatible ABA triblock copolymers. Figure 1 illustrates

Tew, Gregory N.

304

On the Design of Radar Absorbing Materials Using Left-Handed Transmission Line  

Microsoft Academic Search

A novel radar absorbing material is designed by combining a high impedance surface and a transitional structure. The high impedance surface consists of a two-dimensional periodic array of unit cells that are implemented using a left-handed transmission line printed on a dielectric substrate with lumped elements. A transition between free space and the vertically placed microstrip line is designed using

Hang Wang; Wei Tang; Zhongxiang Shen

2007-01-01

305

Left-Handed Materials in Microwave and Infrared Frequencies  

Microsoft Academic Search

Left-handed or negative index metamaterials, i.e. composite materials with electrical permittivity, magnetic permeability and refractive index negative over a common frequency range, have been a subject of extremely increased attention in the last seven years. This is due to the many novel and unusual properties of those materials (like opposite phase and group velocities, negative refraction, etc) which entail unique

M. Kafesaki; C. M. Soukoulis

2007-01-01

306

Comparison of negative refractive index materials with circular, elliptical and  

E-print Network

Comparison of negative refractive index materials with circular, elliptical and rectangular holes Zahyun Ku and S. R. J. Brueck Center for High Technology Materials and Department of Electrical: Negative-index metamaterials (NIMs) at near infrared wavelengths (~2 m) are fabricated with circular

New Mexico, University of

307

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

NASA Technical Reports Server (NTRS)

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.

Rodriguez, Pedro I.

1993-01-01

308

Materials selection for sustainable product design: a case study of wood based furniture eco-design  

Microsoft Academic Search

This article presents an analysis of the environmental impact of the materials and processes typically used in the wood based furniture manufacturing sector. Life cycle assessment methodology was applied to different kinds of wood based boards, surface and edge coverings, and their respective manufacturing processes. For each of these, a life cycle inventory was completed and the environmental impact generated

Mar??a D. Bovea; Rosario Vidal

2004-01-01

309

Materials, Processes and Manufacturing in Ares 1 Upper Stage: Integration with Systems Design and Development  

NASA Technical Reports Server (NTRS)

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.

Bhat, Biliyar N.

2008-01-01

310

Manufacturing process and material selection in concurrent collaborative design of MEMS devices  

NASA Astrophysics Data System (ADS)

In this paper we present knowledge of an intensive approach and system for selecting suitable manufacturing processes and materials for microelectromechanical systems (MEMS) devices in concurrent collaborative design environment. In the paper, fundamental issues on MEMS manufacturing process and material selection such as concurrent design framework, manufacturing process and material hierarchies, and selection strategy are first addressed. Then, a fuzzy decision support scheme for a multi-criteria decision-making problem is proposed for estimating, ranking and selecting possible manufacturing processes, materials and their combinations. A Web-based prototype advisory system for the MEMS manufacturing process and material selection, WebMEMS-MASS, is developed based on the client-knowledge server architecture and framework to help the designer find good processes and materials for MEMS devices. The system, as one of the important parts of an advanced simulation and modeling tool for MEMS design, is a concept level process and material selection tool, which can be used as a standalone application or a Java applet via the Web. The running sessions of the system are inter-linked with webpages of tutorials and reference pages to explain the facets, fabrication processes and material choices, and calculations and reasoning in selection are performed using process capability and material property data from a remote Web-based database and interactive knowledge base that can be maintained and updated via the Internet. The use of the developed system including operation scenario, use support, and integration with an MEMS collaborative design system is presented. Finally, an illustration example is provided.

Zha, Xuan F.; Du, H.

2003-09-01

311

Microwave Nondestructive Evaluation of Dielectric Materials with a Metamaterial Lens  

NASA Technical Reports Server (NTRS)

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.

Shreiber, Daniel; Gupta, Mool; Cravey, Robin L.

2008-01-01

312

The Halogen Bond in the Design of Functional Supramolecular Materials: Recent Advances  

PubMed Central

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

2013-01-01

313

Multiobjective control design including performance robustness for gust alleviation of a wing with adaptive material actuators  

NASA Astrophysics Data System (ADS)

The goal of this paper is to examine the use of covariance control to directly design reduced-order multi-objective controllers for gust alleviation using adaptive materials as the control effector. It will use piezoelectric actuators as control effectors in a finite element model of a full-size wing model. More precisely, the finite element model is of the F-16 Agile Falcon/Active Flexible Wing that is modified to use piezoelectric actuators as control effectors. The paper will also examine the interacting roles of important control design constraints and objectives for designing an aeroservoelastic system. The paper will also present some results of multiobjective control design for the model, illustrating the benefits and complexity of modern practical control design for aeroservoelastic systems that use adaptive materials for actuation.

Layton, Jeffrey B.

1997-06-01

314

Application Concept Maps into Teaching Materials Design: A Case Study of Program Design  

Microsoft Academic Search

Recent advances in network technology are an important form of IT-enabled learning and learning support for on line education. More and more learners obtain knowledge via the Web-learning Instruction (WBI). At present, most of the studies in the on line education are focus on the technological aspect (e.g. Personalizational technology development), while, how to design and arrange the content of

Ling-Hsiu Chen; Yi-Chun Lai

2008-01-01

315

Elementary Students' Learning of Materials Science Practices Through Instruction Based on Engineering Design Tasks  

NASA Astrophysics Data System (ADS)

Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline within the study of matter. This paper examines how third grade students' materials science performance changes over the course of instruction based on an engineering design challenge. We conducted a case study of nine students who participated in engineering design-based science instruction with the goal of constructing a stable, quiet, thermally comfortable model house. The learning outcome of materials science practices was assessed by clinical interviews conducted before and after the instruction, and the learning process was assessed by students' workbooks completed during the instruction. The interviews included two materials selection tasks for designing a sturdy stepstool and an insulated pet habitat. Results indicate that: (1) students significantly improved on both materials selection tasks, (2) their gains were significantly positively associated with the degree of completion of their workbooks, and (3) students who were highly engaged with the workbook's reflective record-keeping tasks showed the greatest improvement on the interviews. These findings suggest the important role workbooks can play in facilitating elementary students' learning of science through authentic activity such as engineering design.

Wendell, Kristen Bethke; Lee, Hee-Sun

2010-12-01

316

Designing and Developing Online Materials for Molecular Biology: Building Online Programs for Science  

PubMed Central

A well-accepted form of educational training offered in molecular biology is internships in research laboratories. However, the number of available research laboratories severely limits access by most students. Addressing this need, the University of Hawaii launched a project to expand this model to include newly developed online training materials in addition to a hands-on laboratory experience. This paper explores the design and development process of the online learning materials. This case study looks at the roles of the instructional designer, multimedia specialist, and research faculty who were the subject matter experts. The experiences of the design teams are shared in an effort to gain insight on how the collaborative efforts of the project group led to a successful deployment of the online learning materials. PMID:24319699

Boulay, Rachel

2013-01-01

317

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

SciTech Connect

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.

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

1992-08-01

318

Li-ion Battery Electrode Materials Design from First-Principles Calculations  

NASA Astrophysics Data System (ADS)

First-principles calculations can provide a powerful tool for investigating and optimizing electrode materials. While the strength of computations lies in the ability to control what is being calculated, the challenge is to ensure that the calculation is relevant for the physical processes that dominate the performance of the material. We will discuss this balance and show examples of how computations can aid in the design of current Li-ion rechargeable battery electrode materials by identifying and understanding the performance bottlenecks on the atomistic level. As the most commonly used anode in today's Li-ion batteries, graphite shows poor rate capability at lower temperatures, leading to over-potential and Li plating. Using first-principles calculations, coupled with a cluster expansion of Li interactions and kinetic Monte Carlo we were able to show that intrinsic Li diffusion in graphite can be very fast, providing guidance towards designing higher-rate carbonaceous anode materials. On the cathode side, we have studied the layered Li(Ni1/3,Mn1/3,Co1/3)O2 material, which is an interesting candidate if Co is partially substituted by the cheaper Al. Li migration in this material is influenced by several factors such as Li slab space, cation ordering and interlayer mixing. We present ab initio calculations of Li diffusivity as a function of Al content and slab spacing in the layered material, which elucidates the intrinsic rate performance effect of the Al substitution in the bulk material.

Persson, Kristin

2011-03-01

319

A rational design of cosolvent exfoliation of layered materials by directly probing liquid–solid interaction  

PubMed Central

Exfoliation of layered materials such as graphite and transition metal dichalcogenides into mono- or few-layers is of significant interest for both the fundamental studies and potential applications. Here we report a systematic investigation of the fundamental factors governing the liquid exfoliation process and the rational design of a cosolvent approach for the exfoliation of layered materials. We show that Young’s equation can be used to predict the optimal cosolvent concentration for the effective exfoliation of graphite and molybdenum disulphide in water mixtures with methanol, ethanol, isopropanol and t-butyl alcohol. Moreover, we find that the cosolvent molecular size has an important role in the exfoliation yield, attributed to the larger steric repulsion provided by the larger cosolvent molecules. Our study provides critical insight into the exfoliation of layered materials, and defines a rational strategy for the design of an environmentally friendly pathway to the high yield exfoliation of layered materials. PMID:23896793

Halim, Udayabagya; Zheng, Chu Ran; Chen, Yu; Lin, Zhaoyang; Jiang, Shan; Cheng, Rui; Huang, Yu; Duan, Xiangfeng

2014-01-01

320

Design of advanced porous graphene materials: from graphene nanomesh to 3D architectures.  

PubMed

In order to make full utilization of the high intrinsic surface area of graphene, recently, porous graphene materials including graphene nanomesh, crumpled graphene and graphene foam, have attracted tremendous attention and research interest, owing to their exceptional porous structure (high surface area, and high pore volume) in combination with the inherent properties of graphene, such as high electronic conductivity, good thermal stability, and excellent mechanical strength. Interestingly, porous graphene materials and their derivatives have been explored in a wide range of applications in the fields of electronic and photonic devices, energy storage, gas separation/storage, oil absorption and sensors. This article reviews recent progress in the synthesis, characterization, properties, and applications of porous graphene materials. We aim to highlight the importance of designing different porous structures of graphene to meet future challenges, and the trend on future design of porous graphene materials is analyzed. PMID:24301688

Jiang, Lili; Fan, Zhuangjun

2014-02-21

321

Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies  

SciTech Connect

The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce compressive residual stress at weld toe for weld fatigue resistance.

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

2005-04-15

322

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

Microsoft Academic Search

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

Meng Deng

2010-01-01

323

Cyclic fatigue testing of five endodontic post designs supported by four core materials  

Microsoft Academic Search

Purpose. This pilot study examined the cyclic fatigue of five endodontic post systems (AccessPost, Flexi-Flange, Flexi-Post, ParaPost, and Vlock) with four core materials (Tytin silver amalgam, Ti-Core, Ketac-Silver and G-C Miracle Mix).Material and methods. In vitro cyclic fatigue was performed with a machine designed to simulate masticatory fatigue forces. An instantaneous force of 22.2 N (5 pounds) was applied to

Brett I. Cohen; Mark K. Pagnillo; Ira Newman; Barry Lee Musikant; Allan S. Deutsch

1997-01-01

324

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

SciTech Connect

The design of a slurry-fed electric gas melter and an examination of the performance and condition of the construction materials were completed. The joule-heated, ceramic-lined melter was constructed to test the applicability of materials and processes for high-level waste vitrification. The developmental Liquid-Fed Ceramic Melter (LFCM) was operated for three years with simulated high-level waste and was subjected to conditions more severe than those expected for a nuclear waste vitrification plant.

Barnes, S.M.; Larson, D.E.

1981-08-01

325

Process Materialization Using Templates and Rules to Design Flexible Process Models  

NASA Astrophysics Data System (ADS)

The main idea in this paper is to show how flexible processes can be designed by combining generic process templates and business rules. We instantiate a process by applying rules to specific case data, and running a materialization algorithm. The customized process instance is then executed in an existing workflow engine. We present an architecture and also give an algorithm for process materialization. The rules are written in a logic-based language like Prolog. Our focus is on capturing deeper process knowledge and achieving a holistic approach to robust process design that encompasses control flow, resources and data, as well as makes it easier to accommodate changes to business policy.

Kumar, Akhil; Yao, Wen

326

The effects of the space environment on damping materials and damping designs on flexible structures  

NASA Technical Reports Server (NTRS)

The effects of space environments on damping materials and damping designs on flexible structures were investigated. The following items were examined: damping of flexible spacecraft appendages; composite loss factor (n sub s) vs. time in high vacuum for damped test beams and damping of flexible structures. The STEP experiments show inherent damping of flexible structures in space effective possible damping design configurations for space structures, effects of passively damped components on the system loss factor of flexible structures and the effect of space environment on properties of damping materials.

Kluesener, M. F.

1984-01-01

327

Design of phononic band gaps in functionally graded piezocomposite materials by using topology optimization  

NASA Astrophysics Data System (ADS)

One of the properties of composite materials is the possibility of having phononic band gaps, within which sound and vibrations at certain frequencies do not propagate. These materials are called Phononic Crystals (PCs). PCs with large band gaps are of great interest for many applications, such as transducers, elastic/ acoustic filters, noise control, and vibration shields. Most of previous works concentrates on PCs made of elastic isotropic materials; however, band gaps can be enlarged by using non-isotropic materials, such as piezoelectric materials. Since the main property of PCs is the presence of band gaps, one possible way to design structures which have a desired band gap is through Topology Optimization Method (TOM). TOM is a computational technique that determines the layout of a material such that a prescribed objective is maximized. Functionally Graded Materials (FGM) are composite materials whose properties vary gradually and continuously along a specific direction within the domain of the material. One of the advantages of applying the FGM concept to TOM is that it is not necessary a discrete 0-1 result, once the material gradation is part of the solution. Therefore, the interpretation step becomes easier and the dispersion diagram obtained from the optimization is not significantly modified. In this work, the main objective is to optimize the position and width of piezocomposite materials band gaps. Finite element analysis is implemented with Bloch-Floquet theory to solve the dynamic behavior of two-dimensional functionally graded unit cells. The results demonstrate that phononic band gaps can be designed by using this methodology.

Vatanabe, Sandro L.; Silva, Emílio C. N.

2011-04-01

328

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

NASA Astrophysics Data System (ADS)

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.

Huddleston, Jeremy; Symmons, Alan; Pini, Ray

2014-06-01

329

Systematic design of phononic band-gap materials and structures by topology optimization.  

PubMed

Phononic band-gap materials prevent elastic waves in certain frequency ranges from propagating, and they may therefore be used to generate frequency filters, as beam splitters, as sound or vibration protection devices, or as waveguides. In this work we show how topology optimization can be used to design and optimize periodic materials and structures exhibiting phononic band gaps. Firstly, we optimize infinitely periodic band-gap materials by maximizing the relative size of the band gaps. Then, finite structures subjected to periodic loading are optimized in order to either minimize the structural response along boundaries (wave damping) or maximize the response at certain boundary locations (waveguiding). PMID:12804226

Sigmund, Ole; Jensen, Jakob Søndergaard

2003-05-15

330

Wiki-Based Rapid Prototyping for Teaching-Material Design in E-Learning Grids  

ERIC Educational Resources Information Center

Grid computing environments with abundant resources can support innovative e-Learning applications, and are promising platforms for e-Learning. To support individualized and adaptive learning, teachers are encouraged to develop various teaching materials according to different requirements. However, traditional methodologies for designing teaching…

Shih, Wen-Chung; Tseng, Shian-Shyong; Yang, Chao-Tung

2008-01-01

331

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

ERIC Educational Resources Information Center

Nutritional genomics, or nutrigenomics, can be considered as the combination of molecular nutrition and genomics. Students who attend courses in nutrigenomics differ with respect to their prior knowledge. This study describes digital nutrigenomics learning material suitable for students from various backgrounds and provides design guidelines for…

Busstra, Maria C.; Hartog, Rob; Kersten, Sander; Muller, Michael

2007-01-01

332

A novel nozzle design for producing hydroentangled nonwoven materials with minimum jet-mark defects  

E-print Network

A novel nozzle design for producing hydroentangled nonwoven materials with minimum jet-mark defects characteris- tics. In this study, different nozzle diameters ranging from 100 lm to 130 lm for the 2nd row were examined in combination with a fixed diameter of 130 lm for the nozzles in the 1st row

Tafreshi, Hooman Vahedi

333

Fusion Engineering and Design 5152 (2000) 681694 Theory and models of material erosion and lifetime during  

E-print Network

Fusion Engineering and Design 51­52 (2000) 681­694 Theory and models of material erosion erosion, possible structural failure and frequent plasma contamination. Surface damage consists instabilities on reactor components. © 2000 Published by Elsevier Science B.V. Keywords: Plasma; Erosion

Harilal, S. S.

334

Design of high performance missile structures utilizing advanced composite material technologies  

Microsoft Academic Search

The U.S. Army Aviation and Missile Command (AMCOM) has demonstrated the ability to develop and utilize advanced composite material technologies for the design and fabrication of hypervelocity kinetic energy missiles for the next generation of Army air defense and anti-tank applications. Future kinetic energy missiles must be small, fast, lethal, and maneuverable, which requires the delivery vehicles to operate in

J. R. Esslinger; R. N. Evans; G. W. Snyder

1999-01-01

335

Facilities layout design optimization with single loop material flow path configuration  

Microsoft Academic Search

Here we formulate the facilities layout design optimization problem for a single loop material flow path configuration. Because of the NP-bard nature of the overall search space, we employ a genetic approach to sample the decomposed search spaces. In addition we analyse the following features of the problem: (1) we estimate lower bounds for the unidirectional flow problem along the

P. BANERJEE; Y. ZHOU

1995-01-01

336

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

E-print Network

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

Abdou, Mohamed

337

Enhancing Learning Through Innovative Technology: Education in 'Surf Equipment, Design, Materials and Construction' Course  

Microsoft Academic Search

This chapter deals with results obtained through active research conducted between 2004 and 2007 in the 'Surf Equipment, Design Materials and Construction' course unit. This 2nd year unit is offered at Edith Cowan (ECU) University (South West Campus) in Bunbury (W.A., Australia) as part of the Surf Science and Technology (SST) course. It aims to engage students in research and

Jaromir Audy

2008-01-01

338

Harnessing instabilities for design of soft reconfigurable auxetic/chiral materials  

E-print Network

instabilities have been traditionally viewed as a failure mode, here we exploit them to design a class of 2D demonstrate a proof-of-concept of the proposed materials. Since the proposed mechanism for reconfigurable-independent. Mechanical instabilities are not always deleterious though they are conventionally regarded as failure modes

339

Incorporating 4MAT Model in Distance Instructional Material--An Innovative Design  

ERIC Educational Resources Information Center

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…

Nikolaou, Alexandra; Koutsouba, Maria

2012-01-01

340

Graphic Design: A Sustainable Solution to Manage the Contents of Teaching Materials  

ERIC Educational Resources Information Center

There is a concern that the teaching of subjects is applied not only with support from a set of technological devices, but largely in the proper use of teaching and new technologies. Taking this idea, the authors develop a research and sustainable design that result in educational materials in solid content and technological innovation, also to…

Victor, Garcia Izaguirre; Luisa, Pier Castello Maria; Eduardo, Arvizu Sanchez

2010-01-01

341

Predicting the crashworthiness of vehicle structures made by lightweight design materials and innovative joining methods  

Microsoft Academic Search

New materials (high strength steel, aluminium) and new joining methods (spot weld-bonding, clinching, toxing, riveting) are increasingly important in body engineering due to the demands of weight and cost reduction in the automotive industry. At the same time manufacturers and customers demands on passive safety are growing. Thin-walled columns are basic components in the concept and design of automotive body

Henning Wallentowitz; Henrik Adam

1996-01-01

342

Design of broad-band radar-absorbing materials for large angles of incidence  

Microsoft Academic Search

A numerical technique, called the (modified) Powell method, is used to design radar-absorbing materials (RAMs) made up of several dielectric layers, usually on top of a conducting (ground) plane. The absorption of RF energy occurs mostly in the last layer. The other layers are used to match the wave impedance of the RAM to that of the medium on which

J. Perini; Lawrence S. Cohen

1993-01-01

343

Journal of Computer-Aided Materials Design, 6: 337347, 1999. KLUWER/ESCOM  

E-print Network

to design experiments on nano-phase materials with minimum adjustable parameters. Keywords: Carbon, Nano, or limited availability of suitable chemical precursors, can limit the composition, type and size [4] of nano Publishers. Printed in the Netherlands. Hierarchical modeling of C and Si nano-cluster nucleation utilizing

Ghoniem, Nasr M.

344

Taguchi statistical design and analysis of cleaning methods for spacecraft materials  

NASA Technical Reports Server (NTRS)

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.

Lin, Y.; Chung, S.; Kazarians, G. A.; Blosiu, J. O.; Beaudet, R. A.; Quigley, M. S.; Kern, R. G.

2003-01-01

345

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

346

APPLICATION FO FLOW FORMING FOR USE IN RADIOACTIVE MATERIAL PACKAGING DESIGNS  

SciTech Connect

This paper reports on the development and testing performed to demonstrate the use of flow forming as an alternate method of manufacturing containment vessels for use in radioactive material shipping packaging designs. Additionally, ASME Boiler and Pressure Vessel Code, Section III, Subsection NB compliance along with the benefits compared to typical welding of containment vessels will be discussed. SRNL has completed fabrication development and the testing on flow formed containment vessels to demonstrate the use of flow forming as an alternate method of manufacturing a welded 6-inch diameter containment vessel currently used in the 9975 and 9977 radioactive material shipping packaging. Material testing and nondestructive evaluation of the flow formed parts demonstrate compliance to the minimum material requirements specified in applicable parts of ASME Boiler and Pressure Vessel Code, Section II. Destructive burst testing shows comparable results to that of a welded design. The benefits of flow forming as compared to typical welding of containment vessels are significant: dimensional control is improved due to no weld distortion; less final machining; weld fit-up issues associated with pipes and pipe caps are eliminated; post-weld non-destructive testing (i.e., radiography and die penetrant tests) is not necessary; and less fabrication steps are required. Results presented in this paper indicate some of the benefits in adapting flow forming to design of future radioactive material shipping packages containment vessels.

Blanton, P.; Eberl, K.; Abramczyk, G.

2012-07-11

347

Optimal nondestructive test design for maximum sensitivity and minimal redundancy for applications in material characterization  

NASA Astrophysics Data System (ADS)

An approach to nondestructive test (NDT) design for material characterization and damage identification in structural components, and more generally in solid continua, is presented and numerically tested. The proposed NDT design approach is based on maximizing a measure of the sensitivity of the test responses to changes in the material properties of the structure while also maximizing a measure of the difference in the response components. As such, the optimally designed NDT provides significant improvement in the ability to solve subsequent inverse characterization problems by extracting the maximum amount of non-redundant information from the system to increase the inverse solution observability. The NDT design approach is theoretically able to include any and all possible design aspects, such as the placement of sensors and actuators and determination of actuation frequency, among others. Through simulated test problems based on the characterization of damage in aluminum structural components utilizing steady-state dynamic surface excitation and localized measurements of displacement, the proposed NDT design approach is shown to provide NDT designs with significantly higher measurement sensitivity as well as lower information redundancy when compared to alternate test approaches. More importantly, the optimized NDT methods are shown to provide consistent and significant improvement in the ability to accurately inversely characterize variations in the Young’s modulus distributions for the simulated test cases considered.

Notghi, Bahram; Brigham, John C.

2013-12-01

348

Materials data requirements for high power target design E. Noah, 4th HPTW, Malm, SE, 2-6 May 2011  

E-print Network

Materials data requirements for high power target design E. Noah, 4th HPTW, Malmö, SE, 2-6 May 2011 Materials Data Requirements For High Power Target Design E. Noah, C. Kharoua, F. Plewinski, P. Sabbagh ESS Target Division 4th HPTW May 2-6, 2011, Malmö #12;Materials data requirements for high power

McDonald, Kirk

349

Block copolymer self assembly for design and vapor phase synthesis of one-dimensional nanostructured materials  

NASA Astrophysics Data System (ADS)

Block copolymer thin films provide a robust method for generating regular, uniform patterns with sub-100 nanometer length scales over arbitrarily large areas. A significant advantage of such block copolymer-based patterning is its ease of integration with all other aspects of traditional thin-film processing, including plasma-based etching and metallization. Such process compatibility ensures a host of application opportunities in designing material properties through control of their nanostructure. Here, we describe our use of block copolymer self assembly for design and vapor phase synthesis of quasi one-dimensional nanostructured materials made of metals, semiconductors, and insulators. The precise control of surface texture afforded by block copolymer-based patterning can influence macroscopic materials properties such as optical reflectance and hydrophobicity.

Rahman, A.; Black, C. T.

2014-06-01

350

Shape optimization and material gradient design of the sharp hot structure  

NASA Astrophysics Data System (ADS)

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.

Ma, Yinji; Yao, Xuefeng; Su, Yunquan

2014-10-01

351

Computer simulations of realistic microstructures: Implications for simulation-based materials design  

NASA Astrophysics Data System (ADS)

The conventional route of materials development typically involves fabrication of numerous batches of specimens having a range of different microstructures generated via variations of process parameters and measurements of relevant properties of these microstructures to identify the combination of processing conditions that yield the material having desired properties. Clearly, such a trial and error based materials development methodology is expensive, time consuming, and inefficient. Consequently, it is of interest to explore alternate strategies that can lead to a decrease in the cost and time required for development of advanced materials such as composites. Availability of powerful and inexpensive computational power and progress in computational materials science permits advancement of modeling and simulations assisted materials design methodology that may require fewer experiments, and therefore, lower cost and time for materials development. The key facets of such a technology would be computational tools for (i) creating models to generate computer simulated realistic microstructures; (ii) capturing the process-microstructure relationship using these models; and (iii) implementation of simulated microstructures in the computational models for materials behavior. Therefore, development of a general and flexible methodology for simulations of realistic microstructures is crucial for the development of simulations based materials design and development technology. Accordingly, this research concerns development of such a methodology for simulations of realistic microstructures based on experimental quantitative stereological data on few microstructures that can capture relevant details of microstructural geometry (including spatial clustering and second phase particle orientations) and its variations with process parameters in terms of a set of simulation parameters. The interpolation and extrapolation of the simulation parameters can then permit generation of atlas of "virtual" microstructures that covers the complete range of variations of processing conditions of interest. These simulated and "virtual" microstructures can then be used in the micromechanical models such as FEM to analyze their constitutive properties.

Singh, Harpreet

352

Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design  

NASA Astrophysics Data System (ADS)

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.

Zhang, Yuxuan; Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David; Zhu, Wenzhong

2014-11-01

353

Metal-organic frameworks as a tunable platform for designing functional molecular materials.  

PubMed

Metal-organic frameworks (MOFs), also known as coordination polymers, represent an interesting class of crystalline molecular materials that are synthesized by combining metal-connecting points and bridging ligands. The modular nature of and mild conditions for MOF synthesis have permitted the rational structural design of numerous MOFs and the incorporation of various functionalities via constituent building blocks. The resulting designer MOFs have shown promise for applications in a number of areas, including gas storage/separation, nonlinear optics/ferroelectricity, catalysis, energy conversion/storage, chemical sensing, biomedical imaging, and drug delivery. The structure-property relationships of MOFs can also be readily established by taking advantage of the knowledge of their detailed atomic structures, which enables fine-tuning of their functionalities for desired applications. Through the combination of molecular synthesis and crystal engineering, MOFs thus present an unprecedented opportunity for the rational and precise design of functional materials. PMID:23944646

Wang, Cheng; Liu, Demin; Lin, Wenbin

2013-09-11

354

Engineered materials characterization report for the Yucca Mountain Site Characterization Project. Volume 2, Design data  

SciTech Connect

This is Volume 2 of the Engineered Materials Characterization Report which presents the design data for candidate materials needed in fabricating different components for both large and medium multi-purpose canister (MPC) disposal containers, waste packages for containing uncanistered spent fuel (UCF), and defense high-level waste (HLW) glass disposal containers. The UCF waste package consists of a disposal container with a basket therein. It is assumed that the waste packages will incorporate all-metallic multibarrier disposal containers to accommodate medium and large MPCs, ULCF, and HLW glass canisters. Unless otherwise specified, the disposal container designs incorporate an outer corrosion-allowance metal barrier over an inner corrosion-resistant metal barrier. The corrosion-allowance barrier, which will be thicker than the inner corrosion-resistant barrier, is designed to undergo corrosion-induced degradation at a very low rate, thus providing the inner barrier protection from the near-field environment for a prolonged service period.

Konynenburg, R.A.; McCright, R.D. [Lawrence Livermore National Lab., CA (United States); Roy, A.K. [B and W Fuel Co., Lynchburg, VA (United States); Jones, D.A. [Nevada Univ., Reno, NV (United States)

1995-08-01

355

The Effect of Rerouting and Tank Car Safety Design on the Risk of Rail Transport of Hazardous Materials  

E-print Network

The Effect of Rerouting and Tank Car Safety Design on the Risk of Rail Transport of Hazardous of Rerouting and Tank Car Safety Design on the Risk of Rail Transport of Hazardous Materials. Proceedings Car Safety Design on the Risk of Rail Transport of Hazardous Materials M. Rapik Saat, Christopher P

Barkan, Christopher P.L.

356

75 FR 22524 - Ocean Dumping; Designation of Ocean Dredged Material Disposal Sites Offshore of the Siuslaw River...  

Federal Register 2010, 2011, 2012, 2013

...Disposal Sites Offshore of the Siuslaw River, Oregon AGENCY: Environmental Protection...finalizes the designation of the Siuslaw River ocean dredged material disposal sites pursuant...dispose of material dredged from the Siuslaw River navigation channel, and to provide a...

2010-04-29

357

A new design of cemented stem using functionally graded materials (FGM).  

PubMed

One of the most frequent complications of total hip replacement (THR) is aseptic loosening of femoral component which is primarily due to changes of post-operative stress distribution pattern with respect to intact femur. Stress shielding of the femur is known to be a principal factor in aseptic loosening of hip replacements. Many designers show that a stiff stem shields the surrounding bone from mechanical loading causing stress shielding. Others show that reducing stem stiffness promotes higher proximal interface shear stress which increases the risk of proximal interface failure. Therefore, the task of this investigation is to solve these conflicting problems appeared in the cemented total hip replacement. The finite element method and optimization technique are used in order to find the optimal stem material which gives the optimal available stress distribution between the proximal medial femoral bone and the cement mantle interfaces. The stem is designed using the concept of functionally graded material (FGM) instead of using the conventional most common used stem material. The results showed that there are four feasible solutions from the optimization runs. The best of these designs is to use a cemented stem graded from titanium at the upper stem layer to collagen at the lower stem layer. This new cemented stem design completely eliminates the stress shielding problem at the proximal medial femoral region. The stress shielding using the cemented functionally graded stem is reduced by 98% compared to titanium stem. PMID:24840196

Hedia, H S; Aldousari, S M; Abdellatif, A K; Fouda, N

2014-01-01

358

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

NASA Technical Reports Server (NTRS)

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.

Scott, Elaine P.; Moncman, Deborah A.

1994-01-01

359

Improved design of cementless hip stems using two-dimensional functionally graded materials.  

PubMed

Increasingly, it is acknowledged that bone resorption around cementless hip implants may cause future problems. The solution is frequently sought in reducing implant stiffness. However, this confronts the designer with a true design conflict: how to reduce the stiffness without excessively loading the proximal bone/prosthesis interface? The aim of this work is to improve the design of cementless hip stem material, using two-dimensional (2D) functionally graded material (FGM) concept in order to solve the above problems. Two models were used in this analysis, using three materials with different elastic moduli, E(1), E(2), and E(3). In model I, the elastic moduli E(1) and E(2) gradually change along the upper stem surface, while E(3) is maintained constant along all the lower surface of the stem. However, in model II, the elastic moduli E(1) and E(2) gradually change along the lower stem surface, while E(3) is maintained constant all along the upper stem surface. It is found that the recommended model is model I, which has three distinct materials of hydroxyapatite, Bioglass, and collagen. The recommended design of 2D FGM is expected to reduce the stress shielding by 91% and 12%, respectively, compared with titanium stem and model II of FGM. It is found that this new design reduces the maximum interface shear stress at the lateral and medial sides of the femur by about 50%, compared with titanium stem. Furthermore, the maximum interface shear stress is reduced by about 17% and 11% at the lateral and medial sides of the femur, respectively, compared with that of model II of FGM. PMID:16506171

Hedia, H S; Shabara, M A N; El-Midany, T T; Fouda, N

2006-10-01

360

In silico design of porous polymer networks: high-throughput screening for methane storage materials.  

PubMed

Porous polymer networks (PPNs) are a class of advanced porous materials that combine the advantages of cheap and stable polymers with the high surface areas and tunable chemistry of metal-organic frameworks. They are of particular interest for gas separation or storage applications, for instance, as methane adsorbents for a vehicular natural gas tank or other portable applications. PPNs are self-assembled from distinct building units; here, we utilize commercially available chemical fragments and two experimentally known synthetic routes to design in silico a large database of synthetically realistic PPN materials. All structures from our database of 18,000 materials have been relaxed with semiempirical electronic structure methods and characterized with Grand-canonical Monte Carlo simulations for methane uptake and deliverable (working) capacity. A number of novel structure-property relationships that govern methane storage performance were identified. The relationships are translated into experimental guidelines to realize the ideal PPN structure. We found that cooperative methane-methane attractions were present in all of the best-performing materials, highlighting the importance of guest interaction in the design of optimal materials for methane storage. PMID:24611543

Martin, Richard L; Simon, Cory M; Smit, Berend; Haranczyk, Maciej

2014-04-01

361

Towards predictor based design of thermodynamic and kinetic properties of complex materials for hydrogen storage  

NASA Astrophysics Data System (ADS)

A calculational approach for the design of new complex materials for hydrogen storage with favorable thermodynamic stability and enhanced diffusion kinetics is presented. By combining density functional theory (DFT) calculations on stable crystal structures and local coordination models with database methods, we perform large-scale screening studies to determine a number of potential alloys/mixtures with favorable thermodynamic stabilities and identify simple descriptors for subsequent materials prediction. Predictors for the kinetic properties of the materials are derived from combining materials screening with path techniques and harmonic transition state theory (TST) to indentify materials parameters, e.g. the hydrogen binding energy, which correlate with the macroscopic diffusion rates. These predictors are then used to design new alloy/mixture compositions and ratios to favor structures with optimal diffusion kinetics. We present results from binary and ternary alkali-transition metal borohydrides and Perovskite based hydrogen permeable membranes, as well as results from studies of binary and mixed metal ammines. Results from the modeling of pathways and rates of dynamical processes involved in the ab-/desorption mechanisms will also be presented and compared to quasi elastic neutron scattering data.

Hummelshoej, Jens

2011-03-01

362

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

SciTech Connect

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.

L. C. Cadwallader

2013-01-01

363

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

SciTech Connect

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.

Stone, Timothy Amos [Los Alamos National Laboratory

2010-01-01

364

Design Features and Capabilities of the First Materials Science Research Rack  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

365

Safety Standard for Oxygen and Oxygen Systems: Guidelines for Oxygen System Design, Materials Selection, Operations, Storage, and Transportation  

NASA Technical Reports Server (NTRS)

NASA's standard for oxygen system design, materials selection, operation, and transportation is presented. Minimum guidelines applicable to NASA Headquarters and all NASA Field Installations are contained.

1996-01-01

366

Road Materials and Pavement Design. Volume X No. X/2001, pages 1 to n Towards a novel framework for handling  

E-print Network

Road Materials and Pavement Design. Volume X ­ No. X/2001, pages 1 to n Towards a novel framework and Pavement Design. Volume X ­ No. X/2001 1. Introduction Nowadays, enterprises are outsourcing their business

Paris-Sud XI, Université de

367

Material Control and Accounting Design Considerations for High-Temperature Gas Reactors  

SciTech Connect

The subject of this report is domestic safeguards and security by design (2SBD) for high-temperature gas reactors, focusing on material control and accountability (MC&A). The motivation for the report is to provide 2SBD support to the Next Generation Nuclear Plant (NGNP) project, which was launched by Congress in 2005. This introductory section will provide some background on the NGNP project and an overview of the 2SBD concept. The remaining chapters focus specifically on design aspects of the candidate high-temperature gas reactors (HTGRs) relevant to MC&A, Nuclear Regulatory Commission (NRC) requirements, and proposed MC&A approaches for the two major HTGR reactor types: pebble bed and prismatic. Of the prismatic type, two candidates are under consideration: (1) GA's GT-MHR (Gas Turbine-Modular Helium Reactor), and (2) the Modular High-Temperature Reactor (M-HTR), a derivative of Areva's Antares reactor. The future of the pebble-bed modular reactor (PBMR) for NGNP is uncertain, as the PBMR consortium partners (Westinghouse, PBMR [Pty] and The Shaw Group) were unable to agree on the path forward for NGNP during 2010. However, during the technology assessment of the conceptual design phase (Phase 1) of the NGNP project, AREVA provided design information and technology assessment of their pebble bed fueled plant design called the HTR-Module concept. AREVA does not intend to pursue this design for NGNP, preferring instead a modular reactor based on the prismatic Antares concept. Since MC&A relevant design information is available for both pebble concepts, the pebble-bed HTGRs considered in this report are: (1) Westinghouse PBMR; and (2) AREVA HTR-Module. The DOE Office of Nuclear Energy (DOE-NE) sponsors the Fuel Cycle Research and Development program (FCR&D), which contains an element specifically focused on the domestic (or state) aspects of SBD. This Material Protection, Control and Accountancy Technology (MPACT) program supports the present work summarized in this report, namely the development of guidance to support the consideration of MC&A in the design of both pebble-bed and prismatic-fueled HTGRs. The objective is to identify and incorporate design features into the facility design that will cost effectively aid in making MC&A more effective and efficient, with minimum impact on operations. The theft of nuclear material is addressed through both MC&A and physical protection, while the threat of sabotage is addressed principally through physical protection.

Trond Bjornard; John Hockert

2011-08-01

368

The SNL100-02 blade : advanced core material design studies for the Sandia 100-meter blade.  

SciTech Connect

A series of design studies are performed to investigate the effects of advanced core materials and a new core material strategy on blade weight and performance for large blades using the Sandia 100-meter blade designs as a starting point. The initial core material design studies were based on the SNL100-01 100- meter carbon spar design. Advanced core material with improved performance to weight was investigated with the goal to reduce core material content in the design and reduce blade weight. A secondary element of the core study was to evaluate the suitability of core materials from natural, regrowable sources such as balsa and recyclable foam materials. The new core strategy for the SNL100-02 design resulted in a design mass of 59 tons, which is a 20% reduction from the most recent SNL100-01 carbon spar design and over 48% reduction from the initial SNL100-00 all-glass baseline blade. This document provides a description of the final SNL100-02 design, includes a description of the major design modifications, and summarizes the pertinent blade design information. This document is also intended to be a companion document to the distribution of the NuMAD blade model files for SNL100-02 that are made publicly available.

Griffith, Daniel

2013-11-01

369

A Strategy to Support Design Processes for Fibre Reinforced Thermoset Composite Materials  

NASA Astrophysics Data System (ADS)

The concept stage in the design for a new composite part is a time when several fundamental decisions must be taken and a considerable amount of the budget is spent. Specialized commercial software packages can be used to support the decision making process in particular aspects of the project (e.g. material selection, numerical analysis, cost prediction,...). However, a complete and integrated virtual environment that covers all the steps in the process is not yet available for the composite design and manufacturing industry. This paper does not target the creation of such an overarching virtual tool, but instead presents a strategy that handles the information generated in each step of the design process, independently of the commercial packages used. Having identified a suitable design parameter shared in common with all design steps, the proposed strategy is able to evaluate the effects of design variations throughout all the design steps in parallel. A case study illustrating the strategy on an industrial part is presented.

Gascons, Marc; Blanco, Norbert; Mayugo, Joan Andreu; Matthys, Koen

2012-06-01

370

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

371

Non-equilibrium materials design: a case study of nanostructured soft magnets for cryogenic applications  

NASA Astrophysics Data System (ADS)

Nanocrystalline soft magnetic materials are the latest and most promising of the soft magnetic materials that were developed at the end of the 20th century. They have since been studied extensively, and various alloy compositions have been developed and optimized for ambient and extreme (cryogenic and elevated temperature) applications. Their advantage lies in the unique combination of fine microstructure, crystal structure and composition, which can be achieved by rapid solidification and subsequent controlled annealing. In this article, we discuss the requirements and the challenges of the alloy designing these alloys and how it affects the crystal structure, microstructure and eventually the magnetic performance of new alloys designed for use at temperatures below 150 K in applications as varied as cryo-power electronics and magnetic shielding. The results from our latest studied alloy series are mentioned as an example.

Daniil, Maria; Knipling, Keith E.; Fonda, Helen M.; Willard, Matthew A.

2014-05-01

372

Design and evaluation of carbon nanotube based optical power limiting materials.  

PubMed

Optical power limiters (OPLs) are "smart materials" that follow passive approaches to provide laser protection. They have the potential for protecting optical sensors and possibly even human eyes from laser-pulse damage. Optical power limiting has been a subject of increasing interest for more than two decades now. The interest is due to the increasingly large number of applications based on lasers that are currently available. Several research groups have been attempting to develop novel OPL materials based on nonlinear optical (NLO) chromophores. As a result, there are a large number of publications and patents on this subject. To date, however, there is not a single OPL material available which, taken individually, can provide ideal and smooth attenuation of an output beam. Therefore, the design and development of radically new types of materials for OPL is urgently required. During the last few years, materials containing carbon nanotubes (CNTs) have established themselves as some of the best-performing optical limiters; however, such materials are difficult to prepare and have issues with stability. In this review, the origin of OPL as well as the mechanisms of OPL are discussed. Ways to modify CNTs to make them suitable for OPL applications is also discussed. PMID:21125817

Rahman, Salma; Mirza, Shamim; Sarkar, Abhijit; Rayfield, George W

2010-08-01

373

Designing and Evaluating a Scientific Training Program and Virtual Learning Materials  

PubMed Central

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

van Raalte, Lisa; Boulay, Rachel

2014-01-01

374

Assembly and insertion of a self-fitting hearing aid: design of effective instruction materials.  

PubMed

A self-fitting hearing aid has been proposed as a viable option to meet the need for rehabilitation in areas where audiology services are unreliable. A successful outcome with a self-fitting hearing aid pivots in part on the clarity of the instructions accompanying the device. The aims of this article are (a) to review the literature to determine features that should be incorporated into written health-care materials and factors to consider in the design process when developing written instructions for a target audience of older adults and (b) to apply this information to the development of a set of written instructions as the first step in self-fitting of a hearing aid, assembling four parts and inserting the aid into the ear. The method involved a literature review of published peer reviewed research. The literature revealed four steps in the development of written health-care materials: planning, design, assessment of suitability, and pilot testing. Best practice design principles for each step were applied in the development of instructions for how to assemble and insert a hearing aid. Separate booklets were developed for the left and right aids and the content of each consisted of simple line drawings accompanied by captions. The reading level was Grade 3.5 equivalent and the Flesch Reading Ease Score was 91.1 indicating that the materials were "very easy" to read. It is essential to follow best practice design principles when developing written health-care materials to motivate the reader, maximize comprehension, and increase the likelihood of successful application of the content. PMID:22389434

Caposecco, Andrea; Hickson, Louise; Meyer, Carly

2011-12-01

375

New Lithium Solid Electrolytes, Thio-Lisicon Materials Design Concept and Application to Solid State Battery  

Microsoft Academic Search

Materials design concept of the new crystalline 'thio-LlSICON' (LIthium Superlonic CONductor) family was discussed. The thio-LISICON was found in the ternary systems, Li2S-MS2-M'xSy (M=Si, Ge, M'=P, Sb, Al, Zn, etc), and showed the highest conductivity of 2.2 × 10-3 Scm-1 at 25°C of any sintered ceramic, together with negligible electronic conductivity, high electrochemical stability, no reaction with lithium metal, and

Ryoji Kanno; Masahiro Murayama; Kazuyuki Sakamoto

2002-01-01

376

Design of single layer wave-absorbers based on lefthanded materials  

Microsoft Academic Search

A physical model of microwave-absorber with an air\\/left-handed material\\/metal structure is proposed, the absorbing characteristics of it is theoretically analyzed, the design fundamentals, ensuring that the absorber has a high absorbing performance in a certain frequency band, and the laws of the distributions of the electromagnetic parameters values satisfying the fundamentals are derived. The results of this work may be

Zhen Hui Zhang; Zheng Ping Wang; Shi Ming Qin; Zhen Ming Wang; Yue Kun Wang

2008-01-01

377

Hygroscopic Swelling Effect on Polymeric Materials and Thermo-hygro-mechanical Design on Finger Printer Package  

Microsoft Academic Search

The objective of this paper is focused on the hygroscopic swelling effect on polymeric material used in electronic package and thermo-hygro-structure coupled design and reliability analysis for finger printer package. For moisture absorption\\/desorption analysis, the ambient environment for temperature and humidity are set to be 60degC60%RH, 85degC60%RH and 85degC85%RH, respectively. The transient moisture diffusion analysis described by Fick's equation is

Hsiang-Chen Hsu; Yu-Teng Hsu; Wen-Lo Hsich; Meng-Chieh Weng; Shao-Tang ZhangJian; Feng-Jui Hsu; Yi-Feng Chen; Shen-Li Fu

2008-01-01

378

Design requirements for SiC\\/SiC composites structural material in fusion power reactor blankets  

Microsoft Academic Search

This paper recalls the main features of the TAURO blanket, a self-cooled Pb-17Li concept using SiC\\/SiC composites as structural material, developed for FPR. The objective of this design activity is to compare the characteristics of present-day industrial SiC-SiC composites with those required for a fusion power reactor blanket and to evaluate the main needs of further R&D. The performed analyses

L. Giancarli; J. P. Bonal; A. Caso; G. Le Marois; N. B. Morley; J. F. Salavy

1998-01-01

379

On the Role of Characterization in the Design of Interfaces in Nanoscale Materials Technology  

NASA Astrophysics Data System (ADS)

This work reviews recent research on the design and control of interfaces in engineering nanomaterials. Four case studies are presented that demonstrate the power of a multimodal approach to the characterization of different types of interfaces. We have used a combination of conventional, high resolution, and analytical transmission electron microscopy, microbeam electron diffraction, and three-dimensional atom probe to study polymer clay nanocomposites, turbine rotor steels used for power generation, multicomponent aluminum alloys, and nanocrystalline magnetic materials.

Ringer, S. P.; Ratinac, K. R.

2004-06-01

380

Strategic materials selection in the automobile body: Economic opportunities for polymer composite design  

Microsoft Academic Search

Previous studies on materials choice in automotive bodies have looked at both composite and aluminum alternatives, but have always found steel to be the most cost-effective option at the production volumes found in the overwhelming majority of vehicle models. This study finds composites to have significant economic potential when considering emerging advances in the polymer composite body-in-white design against the

Erica R. H. Fuchs; Frank R. Field; Richard Roth; Randolph E. Kirchain

2008-01-01

381

Lab 9 The Robust Design Supporting material: Ch 19 of WNC; Ch 15 of CW  

E-print Network

WILD 502 Lab 9 ­ The Robust Design Supporting material: Ch 19 of WNC; Ch 15 of CW Today's lab and the underlying process is described in chapter 15 of CW. All data are for 1 group without age structure_simple1.inp for the 3 models described in section 15.6.1 (page 15-14, 1st full paragraph) of CW: (i

Rotella, Jay J.

382

Materials and design development for bipolar/end plates in fuel cells  

NASA Astrophysics Data System (ADS)

Bipolar/end plate is one of the most important and costliest components of the fuel cell stack and accounts to more than 80% of the total weight of the stack. In the present work, we focus on the development of alternative materials and design concepts for these plates. A prototype one-cell polymer electrolyte membrane (PEM) fuel cell stack made out of SS-316 bipolar/end plate was fabricated and assembled. The use of porous material in the gas flow-field of bipolar/end plates was proposed, and the performance of these was compared to the conventional channel type of design. Three different porous materials were investigated, viz. Ni-Cr metal foam (50 PPI), SS-316 metal foam (20 PPI), and the carbon cloth. It was seen that the performance of fuel cell with Ni-Cr metal foam was highest, and decreased in the order SS-316 metal foam, conventional multi-parallel flow-field channel design and carbon cloth. This trend was explained based on the effective permeability of the gas flow-field in the bipolar/end plates. The use of metal foams with low permeability values resulted in an increased pressure drop across the flow-field which enhanced the cell performance.

Kumar, Atul; Reddy, Ramana G.

383

Information management in the design of materials control and accountability systems  

SciTech Connect

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.

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

1988-01-01

384

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

385

Three-dimensional microstructural design of woven fabric composite material by homogenization method  

SciTech Connect

The strength of woven fabric composite materials depends on the microstructural geometry. However, the conventional methods for mechanical analysis, which have been widely used so far, are insufficient because they cannot take into account for the three-dimensional microstructure. In this study, three-dimensional homogenization method is shown to be effective for the evaluations of the material constants, microscopic stresses and the strength. It has been found that the transverse stresses in the direction of lamination play an important role for the fracture of both fiber bundle and resin. Also, the effect of the mismatched lay-up on the strength has been investigated. It has well been predicted that the mismatched lay-up causes the reduction of the strength and the difference of crack initiation in the resin. These simulations give a new concept of the microstructural design of the composite materials.

Takano, Naoki; Zako, Masaru [Osaka Univ., Suita (Japan). Dept. of Welding and Production Engineering

1995-11-01

386

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

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

387

Computer-Aided Design of Materials for use under High Temperature Operating Condition  

SciTech Connect

The procedures in place for producing materials in order to optimize their performance with respect to creep characteristics, oxidation resistance, elevation of melting point, thermal and electrical conductivity and other thermal and electrical properties are essentially trial and error experimentation that tend to be tremendously time consuming and expensive. A computational approach has been developed that can replace the trial and error procedures in order that one can efficiently design and engineer materials based on the application in question can lead to enhanced performance of the material, significant decrease in costs and cut down the time necessary to produce such materials. The work has relevance to the design and manufacture of turbine blades operating at high operating temperature, development of armor and missiles heads; corrosion resistant tanks and containers, better conductors of electricity, and the numerous other applications that are envisaged for specially structured nanocrystalline solids. A robust thermodynamic framework is developed within which the computational approach is developed. The procedure takes into account microstructural features such as the dislocation density, lattice mismatch, stacking faults, volume fractions of inclusions, interfacial area, etc. A robust model for single crystal superalloys that takes into account the microstructure of the alloy within the context of a continuum model is developed. Having developed the model, we then implement in a computational scheme using the software ABAQUS/STANDARD. The results of the simulation are compared against experimental data in realistic geometries.

Rajagopal, K. R.; Rao, I. J.

2010-01-31

388

Material scarcity: a reason for responsibility in technology development and product design.  

PubMed

There are warning signs for impending scarcity of certain technology metals that play a critical role in high-tech products. The scarce elements are indispensable for the design of modern technologies with superior performance. Material scarcity can restrain future innovations and presents therefore a serious risk that must be counteracted. However, the risk is often underrated in the pursuit of technological progress. Many innovators seem to be inattentive to the limitations in availability of critical resources and the possible implications thereof. The present shortages in industrial supply with technology metals may be interpreted as a wake-up call for technology developers to tackle the issue with due consideration. The article reviews the materials scarcity phenomenon from the viewpoint of sustainable development ethics. The following questions are discussed: 'Should preventative actions be taken today in order to mitigate resource scarcity in future?' and 'Should technology developers feel responsible to do this?' The discussion presents arguments for industrial designers and engineers to create a sense of responsibility for the proactive mitigation of material scarcity. Being protagonists of the innovation system, they have the opportunity to lead change towards resource-aware technology development. The paper concludes by outlining ideas on how they can pioneer sustainable management of critical materials. PMID:23054676

Köhler, Andreas R

2013-09-01

389

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

SciTech Connect

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.

NONE

1995-07-14

390

A geometric algorithm for automated design of multi-stage molds for manufacturing multi-material objects  

Microsoft Academic Search

This paper describes a geometric algorithm for automated design of multi-stage molds for manufacturing multi-material objects. In multi-stage molding process, the desired multi-material object is produced by carrying out multiple molding operations in a sequence, adding one material in the target object in each mold-stage. We model multi-material objects as an assembly of single-material components. Each mold-stage can only add

Malay Kumar; Satyandra K. Gupta

2001-01-01

391

Shielding: quantifying the shielding requirements for portable electronic design and providing new solutions by using a combination of materials and design  

Microsoft Academic Search

Meeting FCC and CISPR 22 radiated EMI standards is a critical issue when designing and packaging electronics: (i) overshielding results in added cost, weight and design complexity; and (ii) undershielding can result in system qualification failures that could potentially delay a product introduction. There are many methods and materials available for shielding and enclosure design. In general, most methods work

David Markham

1999-01-01

392

Development of wideband spectral dispersers for exoplanetary science: comparative study of material, design, and fabrication  

NASA Astrophysics Data System (ADS)

We present the development of wideband spectral dispersers of which the primary scientific objective is the characterization of the atmospheres of exoplanets, including the challenge of detecting biomarkers. A disperser comprising a prism with a grating pattern on its surface provides simultaneous wideband coverage with low spectral resolution (R ? 300). The optics is simple, compact, and contains no moving parts. A comparative study of 21 materials for the disperser was carried out for use in the optical, near-infrared, and mid-infrared wavelength regions. KRS-5, CdZnTe, ZnS LiF, Sapphire, and S-TIH11 were selected, and designs of the optics for single-channel wideband spectrometers using the selected six materials were considered. Then, trial designs of the multi-channel spectrometers were carried out taking the properties of the detectors into consideration. The 3-channel design covers the wavelength region of ˜0.2-23 ?m using a CCD detector, an InSb detector, and a Si:As detector. The 2-channel design covers ˜0.4-23 ?m using a HgCdTe detector and a Si:As detector. A fabricated ZnS disperser is shown together with a CsI subprism which compensates for the optical axis. The application of defocusing, high dispersion spectroscopy, extension to the UV wavelength region, and the combination of the disperser with future space telescopes are discussed.

Enya, Keigo; Fujishiro, Naofumi

2014-09-01

393

High-Temperature Structures, Adhesives, and Advanced Thermal Protection Materials for Next-Generation Aeroshell Design  

NASA Technical Reports Server (NTRS)

The next generation of planetary exploration vehicles will rely heavily on robust aero-assist technologies, especially those that include aerocapture. This paper provides an overview of an ongoing development program, led by NASA Langley Research Center (LaRC) and aimed at introducing high-temperature structures, adhesives, and advanced thermal protection system (TPS) materials into the aeroshell design process. The purpose of this work is to demonstrate TPS materials that can withstand the higher heating rates of NASA's next generation planetary missions, and to validate high-temperature structures and adhesives that can reduce required TPS thickness and total aeroshell mass, thus allowing for larger science payloads. The effort described consists of parallel work in several advanced aeroshell technology areas. The areas of work include high-temperature adhesives, high-temperature composite materials, advanced ablator (TPS) materials, sub-scale demonstration test articles, and aeroshell modeling and analysis. The status of screening test results for a broad selection of available higher-temperature adhesives is presented. It appears that at least one (and perhaps a few) adhesives have working temperatures ranging from 315-400 C (600-750 F), and are suitable for TPS-to-structure bondline temperatures that are significantly above the traditional allowable of 250 C (482 F). The status of mechanical testing of advanced high-temperature composite materials is also summarized. To date, these tests indicate the potential for good material performance at temperatures of at least 600 F. Application of these materials and adhesives to aeroshell systems that incorporate advanced TPS materials may reduce aeroshell TPS mass by 15% - 30%. A brief outline is given of work scheduled for completion in 2006 that will include fabrication and testing of large panels and subscale aeroshell test articles at the Solar-Tower Test Facility located at Kirtland AFB and operated by Sandia National Laboratories. These tests are designed to validate aeroshell manufacturability using advanced material systems, and to demonstrate the maintenance of bondline integrity at realistically high temperatures and heating rates. Finally, a status is given of ongoing aeroshell modeling and analysis efforts which will be used to correlate with experimental testing, and to provide a reliable means of extrapolating to performance under actual flight conditions. The modeling and analysis effort includes a parallel series of experimental tests to determine TSP thermal expansion and other mechanical properties which are required for input to the analysis models.

Collins, Timothy J.; Congdon, William M.; Smeltzer, Stanley S.; Whitley, Karen S.

2005-01-01

394

General design of the International Fusion Materials Irradiation Facility deuteron injector: Source and beam line  

SciTech Connect

In the framework of the International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities (IFMIF-EVEDA) project, CEA/IRFU is in charge of the design and realization of the 140 mA cw deuteron Injector. The electron cyclotron resonance ion source operates at 2.45 GHz and a 4 electrode extraction system has been chosen. A 2 solenoid beam line, together with a high space charge compensation have been optimized for a proper beam injection in the 175 MHz radio frequency quadrupole. The injector will be tested with proton and deuteron beam production either in pulsed mode or in cw mode on the CEA-Saclay site before to be shipped to Japan. Special attention was paid to neutron emission due to (d,D) reaction. In this paper, the general IFMIF Injector design is reported, pointing out beam dynamics, radioprotection, diagnostics, and mechanical aspects.

Gobin, R.; Blideanu, V.; Bogard, D.; Bourdelle, G.; Chauvin, N.; Delferriere, O.; Girardot, P.; Jannin, J. L.; Langlois, S.; Loiseau, D.; Pottin, B.; Rousse, J.-Y.; Senee, F. [Commissariat a l'Energie Atomique, CEA/Saclay, DSM/IRFU, 91191 Gif/Yvette (France)

2010-02-15

395

General design of the International Fusion Materials Irradiation Facility deuteron injector: source and beam line.  

PubMed

In the framework of the International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities (IFMIF-EVEDA) project, CEA/IRFU is in charge of the design and realization of the 140 mA cw deuteron Injector. The electron cyclotron resonance ion source operates at 2.45 GHz and a 4 electrode extraction system has been chosen. A 2 solenoid beam line, together with a high space charge compensation have been optimized for a proper beam injection in the 175 MHz radio frequency quadrupole. The injector will be tested with proton and deuteron beam production either in pulsed mode or in cw mode on the CEA-Saclay site before to be shipped to Japan. Special attention was paid to neutron emission due to (d,D) reaction. In this paper, the general IFMIF Injector design is reported, pointing out beam dynamics, radioprotection, diagnostics, and mechanical aspects. PMID:20192424

Gobin, R; Blideanu, V; Bogard, D; Bourdelle, G; Chauvin, N; Delferrière, O; Girardot, P; Jannin, J L; Langlois, S; Loiseau, D; Pottin, B; Rousse, J-Y; Senée, F

2010-02-01

396

Pre-Service Science and Technology Teachers' Efficacy Beliefs about Information and Communication Technologies (ICT) Usage and Material Design  

ERIC Educational Resources Information Center

In this study, a scale entitled "Information and Communication Technologies Usage and Material Design Efficacy [ICT_MDE]" is developed to investigate pre-service science and technology teachers' efficacy beliefs regarding ICT usage and Material Design and the factors impacting these beliefs. By using the validity and reliability data from 310…

Bursal, Murat; Yigit, Nevzat

2012-01-01

397

Special optical fiber design to reduce reflection peak distortion of a FBG embedded in inhomogeneous material  

NASA Astrophysics Data System (ADS)

During the last decades, the use of optical fiber for sensing applications has gained increasing acceptance because of its unique properties of being intrinsically safe, unsusceptible to EMI, potentially lightweight and having a large operational temperature range. Among the different Fiber Optic sensor types, Fiber Bragg Grating (FBG) is most widely used for its unique multiplexing potential and the possibility of embedding in composite material for Structural Health Monitoring. When the fiber is embedded in an inhomogeneous environment, typically a material composed of filler and base material of different stiffness, local stiff material will generate extra lateral load to the fiber. Via the Poisson effect, this will be converted to a local axial strain. The narrow and sharp peak in the reflection spectrum of an FBG sensor relies on the constant periodicity of the grating. An inhomogeneous axial strain distribution will result in distortion or broadening of the FBG reflection spectrum. For the FBG strain sensitivity of about 1.2pm/??, the spectral distortion can be disastrous for strain measurements. A fiber design to tackle this critical problem is presented. Finite Element Modeling is performed to demonstrate the effectiveness of the solution. Modeling with different configurations has been performed to verify the influence of the design. The deformation of the core in the special fiber depends on the design. For a particular configuration, the core deformation in the axial direction is calculated to be a factor of 10 lower than that of a standard fiber. The first prototype fiber samples were drawn and the manufacturing of FBG in this special fiber using the phase mask method was demonstrated successfully.

Cheng, Lun-Kai; Toet, Peter; de Vreugd, Jan; Nieuwland, Remco; Tse, Ming-Leung Vincent; Tam, Hwayaw

2014-03-01

398

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

SciTech Connect

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.

NONE

1995-07-14

399

Design of a test chamber for the investigation of moisture transport in air flows and porous materials  

Microsoft Academic Search

SUMMARY : This paper describes the design of a test chamber for the investigation of the interaction of humid air and porous materials. Currently computational fluid dynamics (CFD) is gaining in importance as a tool to model the indoor climate in buildings. Meanwhile coupled CFD-material models are being developed which are capable of modelling moisture exchange between air and materials.

Marnix Van Belleghem; Hendrik-Jan Steeman; Michel De Paepe; Marijke Steeman; Arnold Janssens

400

Proceedings of 2008 NSF Engineering Research and Innovation Conference, Knoxville, Tennessee Grant # CMMI-0423485 Multiscale Design of Functionally Graded Materials  

E-print Network

# CMMI-0423485 Multiscale Design of Functionally Graded Materials Senthil S. Vel Associate Professor of functionally graded materials (FGMs). The FGM is engineered to have a spatially varying, but locally periodic that are commonly used to estimate the effective properties of two-phase functionally graded materials including

Vel, Senthil

401

Application of chiral cellular materials for the design of innovative components  

NASA Astrophysics Data System (ADS)

Low-density cellular solids have demonstrated superior mechanical properties as well as multifunctional characteristics, which may provide a basis for the development of novel structured materials. In particular, cellular solids offer great design flexibility, owing to their topology, which can provide desired functionalities via targeted geometric design and proper selection of the constituent material. While stochastic configurations such as metallic foams have proven to be effective for both thermal insulation and mechanical-energy absorption, the topology of deterministic architectures is not constrained by physical processes. This allows for a variety of configurations to be tailored to simultaneously fulfill disparate tasks. An additional aspect of deterministic cellular structures is the possibility of assembling materials or structures by the spatial repetition of a unit cell. The resulting periodicity of such systems simplifies the characterization of physical properties, which can be established by analyzing the unit cell only, and will provide new opportunities in the fields of structural dynamics, where periodicity-induced impedance leads to the control of both constructive and destructive interference on propagating waves. The objective of this work is to investigate the application of the chiral cellular topology for the design of novel macrostructural, mesostructural and microstructural configurations. A truss-core airfoil, and a truss-core beam are employed as a basis to demonstrate both large-displacement capabilities within the elastic regime of the constituent material, as well as operational deflection shapes with localized dynamic deformations. Large deformation capabilities and unique operational deflection shapes are to be attributed to the unusual deformation mechanism of the chiral lattice. Mesostructural and microstructural configurations, on the other hand, are characterized by an unique mechanical behavior, complex geometry, as well as geometric design flexibility to control both static and dynamic phenomena. The propagation of elastic waves, moreover, is characterized by significant band-gap density as well as strong energy focusing dependent on frequency and wavenumber. These features suggest the chiral topology as a basis for the development of acoustic meta-materials.

Spadoni, Alessandro

402

Design optimization of cementless metal-backed cup prostheses using the concept of functionally graded material.  

PubMed

Metal backing has been widely used in acetabular cup design. A stiff backing for a polyethylene liner was initially believed to be mechanically favourable. Yet, recent studies of the load transfer around acetabular cups have shown that a stiff backing causes two problems. It generates higher stress peaks around the acetabular rim than those caused by full polyethylene cups and reduces the stresses transferred to the dome of the acetabulum causing stress shielding. The aim of this study is to overcome these two problems by improving the design of cementless metal-backed acetabular cups using the two-dimensional functionally graded material (FGM) concept through finite-element analysis and optimization techniques. It is found that the optimal 2D FGM model must have three bioactive materials of hydroxyapatite, Bioglass and collagen. This optimal material reduces the stress shielding at the dome of the acetabulum by 40% and 37% compared with stainless steel and titanium metal backing shells, respectively. In addition, using the 2D FGM model reduces the maximum interface shear stress in the bone by 31% compared to the titanium metal backing shell. PMID:18458393

Hedia, H S; El-Midany, T T; Shabara, M A N; Fouda, N

2006-09-01

403

Computational materials design of defect-induced ferrimagnetic MnO.  

PubMed

We present a computational materials design for defect-induced ferrimagnetic MnO. The magnetic properties of MnO containing Mn vacancies were investigated using first-principle calculations. For these electronic structure calculations, we employed a pseudo-self-interaction-corrected local density approximation (PSIC-LDA). We used the Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) to create a random distribution of atoms at the assigned sites. Having described the magnetic properties with a classic Heisenberg model, we calculated the effective exchange coupling constants by applying the magnetic force theorem to two magnetic sites embedded in the CPA medium. We estimated the Curie temperatures from the calculated exchange interactions. This study found that the Mn vacancies induced ferrimagnetic ground states in MnO, and that the Curie temperature could reach room temperature at Mn vacancy concentrations above 20%. These findings suggest a new route for designing ferrimagnetic materials from anti-ferromagnetic host materials. PMID:24553070

Seike, Masayoshi; Fukushima, Tetsuya; Sato, Kazunori; Katayama-Yoshida, Hiroshi

2014-03-12

404

Preparation of Silicon Nitride Multilayer Ceramic Radome Material and Optimal Design of the Wall Structure  

SciTech Connect

A study of silicon nitride ceramic radomes, which includes preparation of the material and optimal design of the radome wall structure, is presented in this paper. Multilayer radome wall structure with high dielectric constant skins and a low dielectric constant core layer is used for broadband application. As a candidate material for both the skins and core layer, silicon nitride ceramics of controlled dielectric constant in the range 3.0{approx}7.5 were prepared by adding different content of sintering aids such as magnesia, alumina, silica and zirconium phosphate binder and choosing suitable sintering methods. A computer aided design (CAD) for the wall structure of silicon nitride multilayer ceramic radome based on microwave equivalent network method is carried out according to design requirements. By optimizing the thickness of skins and core layer, the power transmission efficiency of such a multilayer Si{sub 3}N{sub 4} ceramic radome is calculated. The calculated results suggest that when the dielectric constant of skins lies in the range 6{approx}7.5 and core layer in the range 3.5{approx}4, the power transmission efficiency is above 85% with frequency of 2{approx}18 GHz while the thickness of skins is less than 0.03{lambda} and the thickness ratio of skins to core layer is less than 1:15.

Chen Fei; Shen Qiang; Zhang Lianmeng [State Key Lab of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2008-02-15

405

Material  

E-print Network

This edition of MaterialEASE focuses on materials selection in general while paying particular attention to the increasing use of the computer in the selection process. Many of the commercial products associated with computer-aided materials selection are evaluated along with an analysis of the development trends. MaterialEASE is also available at AMPTIAC’s Web stie … www.rome.iitri.com/amptiac.

unknown authors

406

Material design for immersion lithography with high refractive index fluid (HIF)  

NASA Astrophysics Data System (ADS)

ArF immersion lithography is considered as the most promising next generation technology which enables to a 45 nm node device manufacturing and below. Not only depth of focus enlargement, immersion lithography enables to use hyper numerical aperture (NA) larger than 1.0 and achieve higher resolution capability. For 193nm lithography, water is an ideal immersion fluid, providing suitable refractive index and transmission properties. Furthermore the higher refractive index fluid is expected to provide a potential extension of optical lithography to the 32 nm node. This paper describes the material design for immersion lithography with high refractive index fluid. We have developed promising high refractive index fluids which satisfy the requirement for immersion fluid by screening wide variety of organic compounds. The physical and chemical properties of this high refractive index fluid are discussed in detail. Also the topcoat material which has good matching with high refractive index fluid is developed. While this topcoat material is soluble into aqueous TMAH developer, it does not dissolve into water or high refractive index fluid and gives suitable contact angle for immersion scan exposure. Immersion exposure experiments using high refractive index fluid with and w/o topcoat material was carried out and its lithographic performance is presented in this paper.

Miyamatsu, Takashi; Wang, Yong; Shima, Motoyuki; Kusumoto, Shiro; Chiba, Takashi; Nakagawa, Hiroki; Hieda, Katsuhiko; Shimokawa, Tsutomu

2005-05-01

407

Design of self-growing, self-sensing, and self-repairing materials for engineering applications  

NASA Astrophysics Data System (ADS)

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 the innate attributes of the material without much labor. They sense the environment, respond to it, and repair any damage. This composite bridge is designed from a self-forming polymer and concrete system. Internal release of chemicals, their properties and location account for responsiveness to change and for repair. The choice of matrix additives also allow for the responsiveness. Bridge frames were fabricated for dynamic testing. The results showed that self repair and response to loads could be accomplished by careful placement of chemicals for later release and by use of chemicals which could alter such attributes as stiffness, flexure and permanent deformation. Internal viewing sensors could determine the state of the frames after testing.

Dry, Carolyn M.

2001-04-01

408

Beetle forewings: Epitome of the optimal design for lightweight composite materials.  

PubMed

Based on studies of the forewings of two beetles, Allomyrina dichotoma and Prosopocoilus inclinatus, this paper reviews and identifies the potential benefits of studying the structure of the beetle forewing and the associated development of lightweight biomimetic composite materials. The forewings of both beetle species consist of an integrated border frame structure and a large center part with distributed trabecular supports in the hollow core. The forewings of the male A. dichotoma are constructed to reflect a lightweight honeycomb design. However, the forewings of P. inclinatus are a durable structure. The biological significance of these structures is also discussed. This work proposes an integrated honeycomb structure inspired by the beetle forewing. A series of biological models are also proposed for lightweight integrated honeycomb structures and durable sandwich structures with a trabecular core, which are intended to establish a new direction in the development of biomimetic composite materials. PMID:23121961

Chen, Jinxiang; Wu, Gang

2013-01-16

409

Design, synthesis, and characterization of KrF negative developable bottom anti-reflective coating materials  

NASA Astrophysics Data System (ADS)

Negative photoresist materials for 248 nm (KrF excimer laser) implant applications are of interest to research and development recently, due to the ever-present demand to shrink lithographically-patterned device dimensions at an affordable cost. Challenges to developing such a successful resist are the topography of the substrate and subsequent reflectivity complexities. Substrate reflectivity control, resist profile, and critical dimension (CD) uniformity are critical issues that must be addressed to enable robust lithography performance at high KrF numerical aperture. The design, synthesis and characterization of a series of polymers for negative developable bottom anti-reflective coating (NDBARC) materials suitable for KrF negative implant resists is described.

Liu, Sen; Chen, Kuang-Jung; Huang, Wu-Song; Holmes, Steven; Huang, Karen; Fender, Nicolette; Kwong, Ranee; Osborn, Brian; Tang, Cherry; Wu, Chung-Hsi; Slezak, Mark

2012-03-01

410

Materials design concepts for efficient blue OLEDs: A joint theoretical and experimental study  

SciTech Connect

Since their discovery, organic light emitting devices have evolved from a scientific curiosity into a technology with applications in flat panel displays and the potential to revolutionize the lighting market. During their relatively short history, the technology incorporated into OLEDs has rapidly advanced. Device quantum efficiencies have increased more than 20-fold since the first OLEDs, approaching the theoretical limit for internal quantum efficiencies. , , At this point, OLED research moves towards optimization of manufacturing processes, drive circuitry, light extraction, and overall cost reduction. However, finding the organic materials that provide both operational stability and high efficiency for the devices still remains one of the biggest challenges, particularly for blue emission. In this presentation, we will describe our approach to design functional OLED materials to meet the complex criteria set forth by device efficiency and stability goals.

Polikarpov, Evgueni; Padmaperuma, Asanga B.

2012-04-01

411

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

NASA Technical Reports Server (NTRS)

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.

Bednarcyk, Brett A.; Arnold, Steven M.

2011-01-01

412

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

SciTech Connect

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.

Thackeray, M.; Chemical Sciences and Engineering Division

2007-01-01

413

Three-dimensional biomaterial degradation - Material choice, design and extrinsic factor considerations.  

PubMed

The apparent difficulty to precisely control fine-tuning of biomaterial degradation has initiated the recent paradigm shift from conventional top-down fabrication methods to more nature-inspired bottom-up assemblies. Sophistication of material fabrication techniques allows today's scientists to reach beyond conventional natural materials in order to synthesise tomorrow's 'designer material'. Material degradation into smaller components and subsequent release of encapsulated cells or cell-signalling agents have opened medically exploitable avenues, transforming the area of regenerative medicine into a dynamic and self-propagating branch of modern medicine. The aim to synthesise ever more refined scaffolding structures in order to create micro- and nanoenvironments resembling those found in natural tissues now represents an ever growing niche in the materials sciences. Recently, we have developed and conducted the world's first in-human tracheal transplantation using a non-degradable completely synthetic biomaterial. Fuelled by such clinical potential, we are currently developing a biodegradable version suitable for skin tissue engineering and paediatric applications. However, despite enormous efforts, current, as yet insurmountable challenges include precise biomaterial degradation within pre-determined spatial and temporal confines in an effort to release bio-signalling agents in such orchestrated fashion as to fully regenerate functioning tissues. In this review, the authors, almost anti-climactically, ask the readers to step out of the artificially over-constructed spiral of ever more convoluted scaffold fabrication techniques and consider the benefits of controllable bottom-up scaffold fabrication methods. It will further be investigated how scaffold designs and fabrication methods may influence degradation and subsequent release of incorporated elements. A focus will be placed on the delivery of growth factors, stem cells and therapeutic agents alone or in parallel. The difficulties of designing a delivery vehicle capable of delivering multiple factors whilst maintaining distinct release kinetics will be highlighted. Finally, this review will be rounded off with an insight into current literature addressing the recurring issues of degradation product toxicities and suggests means of overcoming those. PMID:24858478

Yildirimer, Lara; Seifalian, Alexander M

2014-01-01

414

Uniformity Masks Design Method Based on the Shadow Matrix for Coating Materials with Different Condensation Characteristics  

PubMed Central

An intuitionistic method is proposed to design shadow masks to achieve thickness profile control for evaporation coating processes. The proposed method is based on the concept of the shadow matrix, which is a matrix that contains coefficients that build quantitive relations between shape parameters of masks and shadow quantities of substrate directly. By using the shadow matrix, shape parameters of shadow masks could be derived simply by solving a matrix equation. Verification experiments were performed on a special case where coating materials have different condensation characteristics. By using the designed mask pair with complementary shapes, thickness uniformities of better than 98% are demonstrated for MgF2 (m = 1) and LaF3 (m = 0.5) simultaneously on a 280?mm diameter spherical substrate with the radius curvature of 200?mm. PMID:24227996

2013-01-01

415

Design of spectrally tailored fusion reactor materials experiments in the HFIR RB? capsule irradiation facility  

NASA Astrophysics Data System (ADS)

Design of four spectrally tailored capsules to irradiate magnetic fusion energy (MFE) materials specimens in the new High Flux Isotope Reactor (HFIR) removable beryllium (RB?) facility at temperatures of 60, 200, 330 and 400°C, is described. These designs incorporate provisions for removal, examination and reencapsulation of the specimens at intermediate exposure levels en route to a target exposure level of 30 displacements per atom (dpa). With the exception of the 60°C capsule, where the test specimens are in direct contact with the reactor cooling water, the specimen temperatures (monitored by 21 thermocouples) are controlled by varying the thermal conductance of a small gap region between the specimen holder and the containment tube. Hafnium shields are used to tailor the neutron spectrum to closely match the helium production-to-atom displacement ratio ( {14 appm}/{dpa}) expected in an austenitic stainless steel fusion reactor first wall. These MFE capsule irradiations will begin in early 1988.

Longest, A. W.; Corum, J. E.; Heatherly, D. W.; Thoms, K. R.

1988-07-01

416

Applications of molecular modeling to the design and characterization of materials  

SciTech Connect

A variety of new molecular modeling tools are now available for studying molecular structures and molecular interactions, for building molecular structures from simple components using analytical data, and for studying the relationship of molecular structure to the energy of bonding and non-bonding interactions. These are proving quite valuable in characterizing molecular structures and intermolecular interactions and in designing new molecules. This paper describes the application of molecular modeling techniques to a variety of materials problems, including the probable modecular structures of coals, lignins, and hybrid inorganic-organic-organic systems (silsesquioxanes), the intercalation of small gas molecules in fullerene crystals, the diffusion of gas molecules through membranes, and the design, structure and function of biomimetic and nanocluster catalysts.

Carlson, G.A.; Faulon, J.L.; Pohl, P.I.; Shelnutt, J.A.

1994-06-01

417

Integrating Materials, Manufacturing, Design and Validation for Sustainability in Future Transport Systems  

NASA Astrophysics Data System (ADS)

The predictive methods currently used for material specification, component design and the development of manufacturing processes, need to evolve beyond the current `metal centric' state of the art, if advanced composites are to realise their potential in delivering sustainable transport solutions. There are however, significant technical challenges associated with this process. Deteriorating environmental, political, economic and social conditions across the globe have resulted in unprecedented pressures to improve the operational efficiency of the manufacturing sector generally and to change perceptions regarding the environmental credentials of transport systems in particular. There is a need to apply new technologies and develop new capabilities to ensure commercial sustainability in the face of twenty first century economic and climatic conditions as well as transport market demands. A major technology gap exists between design, analysis and manufacturing processes in both the OEMs, and the smaller companies that make up the SME based supply chain. As regulatory requirements align with environmental needs, manufacturers are increasingly responsible for the broader lifecycle aspects of vehicle performance. These include not only manufacture and supply but disposal and re-use or re-cycling. In order to make advances in the reduction of emissions coupled with improved economic efficiency through the provision of advanced lightweight vehicles, four key challenges are identified as follows: Material systems, Manufacturing systems, Integrated design methods using digital manufacturing tools and Validation systems. This paper presents a project which has been designed to address these four key issues, using at its core, a digital framework for the creation and management of key parameters related to the lifecycle performance of thermoplastic composite parts and structures. It aims to provide capability for the proposition, definition, evaluation and demonstration of advanced lightweight structures for new generation vehicles in the context of whole life performance parameters.

Price, M. A.; Murphy, A.; Butterfield, J.; McCool, R.; Fleck, R.

2011-05-01

418

Materials, design, and modeling for bipolar/end plates in polymer electrolyte membrane fuel cells  

NASA Astrophysics Data System (ADS)

New vehicle technologies are required to improve upon conventional internal combustion engine technologies. In this regard, the development of fuel cell (polymer electrolyte membrane type) vehicles with improved efficiency and reliability seems promising. However, some technical issues exist that hinder the commercialization of this technology. One such issue is the high cost, volume, and mass of the bipolar/end plates in the polymer electrolyte membrane fuel cell (PEMFC) stack. This research, therefore, focuses on materials, design, and modeling for bipolar/end plates in PEMFC stack. Alternative materials were tested that can replace the conventionally used graphite in the PEMFC stack. With regards to these, a two-cell PEMFC stack was fabricated with SS-316 multi-parallel flow-field (MPFF) designed bipolar/end plates. The stack was run for over 1000 hours and showed no appreciable drop in performance. To enhance the understanding and for determining the effect of operating parameters in PEMFC, a single cell model was developed. The model results agree well with the experimental data. The gas flow-field in bipolar/end plates of the PEMFC was optimized with respect to channel dimensions, channel shape, flow-field design, and flow-field permeability. It was seen that lower the flow-field permeability better is the fuel cell performance. Based on this, the concept of use of metal foams in the gas flow-field was proposed. Experiments were carried out to test the feasibility of metal foams in the gas flow-field of bipolar/end plates in PEMFC stack. Three different porous materials, viz. Ni-Cr metal foam (50 P PI, pores per inch), S S-316 metal foam (20 PPI), and carbon cloth were tested, and the results were compared to the conventional MPFF channel design concept. It was seen that the performance with Ni-Cr metal foam was highest, and decreased in the order of SS-316 metal foam, conventional MPFF design, and carbon cloth. This trend was explained based on the effective permeability of the gas flow-field. Lower permeability values result in more tortuous path for the gases and consequently in an increased pressure drop which enhanced the cell performance.

Kumar, Atul

419

Design and Development of a Composite Dome for Experimental Characterization of Material Permeability  

NASA Technical Reports Server (NTRS)

This paper presents the design and development of a carbon fiber reinforced plastic dome, including a description of the dome fabrication, method for sealing penetrations in the dome, and a summary of the planned test series. This dome will be used for the experimental permeability characterization and leakage validation of composite vessels pressurized using liquid hydrogen and liquid nitrogen at the Cryostat Test Facility at the NASA Marshall Space Flight Center (MSFC). The preliminary design of the dome was completed using membrane shell analysis. Due to the configuration of the test setup, the dome will experience some flexural stresses and stress concentrations in addition to membrane stresses. Also, a potential buckling condition exists for the dome due to external pressure during the leak testing of the cryostat facility lines. Thus, a finite element analysis was conducted to assess the overall strength and stability of the dome for each required test condition. Based on these results, additional plies of composite reinforcement material were applied to local regions on the dome to alleviate stress concentrations and limit deflections. The dome design includes a circular opening in the center for the installation of a polar boss, which introduces a geometric discontinuity that causes high stresses in the region near the hole. To attenuate these high stresses, a reinforcement system was designed using analytical and finite element analyses. The development of a low leakage polar boss system is also investigated.

Estrada, Hector; Smeltzer, Stanley S., III

1999-01-01

420

Design-Optimization and Material Selection for a Proximal Radius Fracture-Fixation Implant  

NASA Astrophysics Data System (ADS)

The problem of optimal size, shape, and placement of a proximal radius-fracture fixation-plate is addressed computationally using a combined finite-element/design-optimization procedure. To expand the set of physiological loading conditions experienced by the implant during normal everyday activities of the patient, beyond those typically covered by the pre-clinical implant-evaluation testing procedures, the case of a wheel-chair push exertion is considered. Toward that end, a musculoskeletal multi-body inverse-dynamics analysis is carried out of a human propelling a wheelchair. The results obtained are used as input to a finite-element structural analysis for evaluation of the maximum stress and fatigue life of the parametrically defined implant design. While optimizing the design of the radius-fracture fixation-plate, realistic functional requirements pertaining to the attainment of the required level of the devise safety factor and longevity/lifecycle were considered. It is argued that the type of analyses employed in the present work should be: (a) used to complement the standard experimental pre-clinical implant-evaluation tests (the tests which normally include a limited number of daily-living physiological loading conditions and which rely on single pass/fail outcomes/decisions with respect to a set of lower-bound implant-performance criteria) and (b) integrated early in the implant design and material/manufacturing-route selection process.

Grujicic, M.; Xie, X.; Arakere, G.; Grujicic, A.; Wagner, D. W.; Vallejo, A.

2010-11-01

421

IFMIF, International Fusion Materials Irradiation Facility conceptual design activity cost report  

SciTech Connect

This report documents the cost estimate for the International Fusion Materials Irradiation Facility (IFMIF) at the completion of the Conceptual Design Activity (CDA). The estimate corresponds to the design documented in the Final IFMIF CDA Report. In order to effectively involve all the collaborating parties in the development of the estimate, a preparatory meeting was held at Oak Ridge National Laboratory in March 1996 to jointly establish guidelines to insure that the estimate was uniformly prepared while still permitting each country to use customary costing techniques. These guidelines are described in Section 4. A preliminary cost estimate was issued in July 1996 based on the results of the Second Design Integration Meeting, May 20--27, 1996 at JAERI, Tokai, Japan. This document served as the basis for the final costing and review efforts culminating in a final review during the Third IFMIF Design Integration Meeting, October 14--25, 1996, ENEA, Frascati, Italy. The present estimate is a baseline cost estimate which does not apply to a specific site. A revised cost estimate will be prepared following the assignment of both the site and all the facility responsibilities.

Rennich, M.J. [comp.

1996-12-01

422

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

423

Design and validation of optimal experiments for estimating thermal properties of composite materials  

SciTech Connect

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 to harsh thermal loads. An understanding of the thermal behavior of these materials became necessary. The thrust of this work is the estimation of two thermal parameters: thermal conductivity and volumetric heat capacity. There are three main parts to the current research; each part describes a different aspect of estimating these thermal properties. The first part compares two experimental research paradigms pertaining to the effect of the temperature rise on the estimated parameters during transient parameter estimation experiments. The second part of this research relates to optimal experiments. Two one-dimensional experiments for finite and semi-infinite geometries are shown to be superior to some previously published ones. The two experimental parameters of heating time and cooling time are especially of interest for these experiments. A two-dimensional case is studied following the same methodology. Design curves relating the optimality criterion to the geometry and directional properties of the material of interest are obtained. The analytical results of the optimal experiments pertaining to the finite one-dimensional geometry are verified using an experimental technique developed by Garnier and Beck. In the third part of this research, the thermocouple-induced errors, which are usually small quantities, are quantified using an analytical approach. Finite difference and finite element methods are supplemented because of their limitations in calculating small differences.

Taktak, R.

1992-01-01

424

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

NASA Astrophysics Data System (ADS)

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).

Periasamy, Prakash

425

Multiscale design and multiobjective optimization of orthopedic hip implants with functionally graded cellular material.  

PubMed

Revision surgeries of total hip arthroplasty are often caused by a deficient structural compatibility of the implant. Two main culprits, among others, are bone-implant interface instability and bone resorption. To address these issues, in this paper we propose a novel type of implant, which, in contrast to current hip replacement implants made of either a fully solid or a foam material, consists of a lattice microstructure with nonhomogeneous distribution of material properties. A methodology based on multiscale mechanics and design optimization is introduced to synthesize a graded cellular implant that can minimize concurrently bone resorption and implant interface failure. The procedure is applied to the design of a 2D left implanted femur with optimized gradients of relative density. To assess the manufacturability of the graded cellular microstructure, a proof-of-concept is fabricated by using rapid prototyping. The results from the analysis are used to compare the optimized cellular implant with a fully dense titanium implant and a homogeneous foam implant with a relative density of 50%. The bone resorption and the maximum value of interface stress of the cellular implant are found to be over 70% and 50% less than the titanium implant while being 53% and 65% less than the foam implant. PMID:22482684

Arabnejad Khanoki, Sajad; Pasini, Damiano

2012-03-01

426

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

SciTech Connect

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.

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

1998-04-01

427

Materials  

Microsoft Academic Search

Materials play an important role in manufactured goods. Materials must possess both acceptable properties for their intended\\u000a applications and a suitable ability to be manufactured. These criteria hold true for micromanufacturing, in which parts have\\u000a overall dimensions of less than 1 mm. This chapter begins by reviewing materials usage in Asian and European research in micromanufacturing,\\u000a categorized by manufacturing process.

David Bourell; Kamlakar Rajurkar

428

Hierarchical zeolites: enhanced utilisation of microporous crystals in catalysis by advances in materials design.  

PubMed

The introduction of synthetic zeolites has led to a paradigm shift in catalysis, separations, and adsorption processes, due to their unique properties such as crystallinity, high-surface area, acidity, ion-exchange capacity, and shape-selective character. However, the sole presence of micropores in these materials often imposes intracrystalline diffusion limitations, rendering low utilisation of the zeolite active volume in catalysed reactions. This critical review examines recent advances in the rapidly evolving area of zeolites with improved accessibility and molecular transport. Strategies to enhance catalyst effectiveness essentially comprise the synthesis of zeolites with wide pores and/or with short diffusion length. Available approaches are reviewed according to the principle, versatility, effectiveness, and degree of reality for practical implementation, establishing a firm link between the properties of the resulting materials and the catalytic function. We particularly dwell on the exciting field of hierarchical zeolites, which couple in a single material the catalytic power of micropores and the facilitated access and improved transport consequence of a complementary mesopore network. The carbon templating and desilication routes as examples of bottom-up and top-down methods, respectively, are reviewed in more detail to illustrate the benefits of hierarchical zeolites. Despite encircling the zeolite field, this review stimulates intuition into the design of related porous solids (116 references). PMID:18949124

Pérez-Ramírez, Javier; Christensen, Claus H; Egeblad, Kresten; Christensen, Christina H; Groen, Johan C

2008-11-01

429

Recent progress in computer-aided materials design for compound semiconductors  

NASA Astrophysics Data System (ADS)

Recent progress in computational materials science in the area of semiconductor materials is reviewed. Reliable predictions can now be made for a wide range of problems, such as band structure and structural and thermodynamic properties of various compound semiconductors, using electronic theories such as the pseudopotential method. Further applications are examined by investigating the behavior of various atomic species in semiconductors, including the stability and band structure of heterostructures, superlattices, lattice defects, alloy systems, and surface-related properties such as surface reconstruction, surface passivation, and adatom migration during thin film growth. The empirical interatomic potentials, pseudopotential, and stochastic Monte Carlo methods are used. An overview of these issues is provided and the latest achievements are presented to illustrate the capability of the theoretical-computational approach by comparing experimental results. The constituents of the semiconductors that are most applicable to electronic and optical devices, mainly group-II, -III, -IV, -V, and -VI elements, are focused on. These successful applications of the theoretical-computational approach lead to future prospects for the computer-aided materials design for semiconductors introduced as ``bond engineering.''

Ito, Tomonori

1995-05-01

430

Life Predicted in a Probabilistic Design Space for Brittle Materials With Transient Loads  

NASA Technical Reports Server (NTRS)

Analytical techniques have progressively become more sophisticated, and now we can consider the probabilistic nature of the entire space of random input variables on the lifetime reliability of brittle structures. This was demonstrated with NASA s CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code combined with the commercially available ANSYS/Probabilistic Design System (ANSYS/PDS), a probabilistic analysis tool that is an integral part of the ANSYS finite-element analysis program. ANSYS/PDS allows probabilistic loads, component geometry, and material properties to be considered in the finite-element analysis. CARES/Life predicts the time dependent probability of failure of brittle material structures under generalized thermomechanical loading--such as that found in a turbine engine hot-section. Glenn researchers coupled ANSYS/PDS with CARES/Life to assess the effects of the stochastic variables of component geometry, loading, and material properties on the predicted life of the component for fully transient thermomechanical loading and cyclic loading.

Nemeth, Noel N.; Palfi, Tamas; Reh, Stefan

2005-01-01

431

Waste package design and container materials evaluation for the Yucca Mountain repository  

SciTech Connect

Container material concerns for the long-term containment of high-level reprocessed nuclear waste and spent nuclear fuel in a potential repository at Yucca Mountain, Nevada are discussed. The current container design focuses on a thin corrosion resistant inner barrier surrounded by a thick corrosion allowance outer barrier. Carbon steel is the principal candidate material for the outer barrier, while Ni-Cr-Mo alloys are the main focus for the inner barrier. The repository is initially expected to be hot and dry, but as the temperature decreases, the possibility of a humid environment and liquid water entry into the repository zone increases. Gradual wastage of the outer barrier delays access of water to the inner barrier, which is expected to be resistant to most forms of corrosion. The creviced region between the two barriers, however, may provide an area of localized corrosion on the inner barrier. Galvanic effects between the two barrier materials introduce some complexities in the same creviced region. A testing program has been initiated to measure corrosion rates, determine the kinds of corrosion attack, and provide input for the long-term performance modeling of the container.

McCright, R.D.; Clarke, W.L. [Lawrence Livermore National Lab., CA (United States)

1998-12-31

432

Novel Solar Energy Conversion Materials by Design of Mn(II) Oxides  

SciTech Connect

Solar energy conversion materials need to fulfill simultaneously a number of requirements in regard of their band-structure, optical properties, carrier transport, and doping. Despite their desirable chemical properties, e.g., for photo-electrocatalysis, transition-metal oxides usually do not have desirable semiconducting properties. Instead, oxides with open cation d-shells are typically Mott or charge-transfer insulators with notoriously poor transport properties, resulting from large effective electron/hole masses or from carrier self-trapping. Based on the notion that the electronic structure features (p-d interaction) supporting the p-type conductivity in d10 oxides like Cu2O and CuAlO2 occurs in a similar fashion also in the d5 (high-spin) oxides, we recently studied theoretically the band-structure and transport properties of the prototypical binary d5 oxides MnO and Fe2O3 [PRB 85, 201202(R)]. We found that MnO tends to self-trap holes by forming Mn+III, whereas Fe2O3 self-traps electrons by forming Fe+II. However, the self-trapping of holes is suppressed by when Mn is tetrahedrally coordinated, which suggests specific routes to design novel solar conversion materials by considering ternary Mn(II) oxides or oxide alloys. We are presenting theory, synthesis, and initial characterization for these novel energy materials.

Lany, S.; Peng, H.; Ndione, P.; Zakutayev, A.; Ginley, D. S.

2013-01-01

433

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

434

Design and performance of a vacuum-UV simulator for material testing under space conditions  

E-print Network

This paper describes the construction and performance of a VUV-simulator that has been designed to study degradation of materials under space conditions. It is part of the Complex Irradiation Facility at DLR in Bremen, Germany, that has been built for testing of material under irradiation in the complete UV-range as well as under proton and electron irradiation. Presently available UV-sources used for material tests do not allow the irradiation with wavelengths smaller than about $115$ nm where common Deuterium lamps show an intensity cut-off. The VUV-simulator generates radiation by excitation of a gas-flow with an electron beam. The intensity of the radiation can be varied by manipulating the gas-flow and/or the electron beam. The VUV simulator has been calibrated at three different gas-flow settings in the range from $40$ nm to $410$ nm. The calibration has been made by the Physikalisch-Technische Bundesanstalt (PTB) in Berlin. The measured spectra show total irradiance intensities from $24$ to $58$ mW$\\rm...

Sznajder, Maciej; Witzke, Andreas; Geppert, Ulrich; Thornagel, Reiner

2014-01-01

435

Design strategies for achieving high triplet energy electron transporting host materials for blue electrophosphorescence  

SciTech Connect

High efficiency small molecule organic light emitting devices (OLEDs) based on light emission from an electrophosphorescent dopant dispersed in an organic host matrix are well known. Achieving blue phosphorescent OLEDs is particularly challenging because the host triplet energy should ideally be > 2.8 eV to prevent back-transfer of energy from the dopant to the host matrix resulting in loss of efficiency. A design strategy for developing new host materials with high triplet energies by using phosphine oxide (P=O) moieties as points of saturation in order to build sublimable, electron transporting host materials starting from small, wide bandgap molecular building blocks (i.e., biphenyl, phenyl, naphthalene, octafluorobiphenyl, and N-ethylcarbazole) is described. Electrophosphorescent OLEDs using the organic phosphine oxide compounds as host materials for the sky blue organometallic phosphor, iridium(III)bis(4,6-(di-fluorophenyl)-pyridinato-N,C2’) picolinate (FIrpic) give maximum external quantum efficiencies of ~ 8% and maximum luminance power efficiencies up to 25 lm/W.

Sapochak, Linda S.; Padmaperuma, Asanga B.; Vecchi, Paul A.; Qiao, Hong (Amy); Burrows, Paul E.

2006-12-01

436

Design Issues for Using Magnetic Materials in Radiation Environments at Elevated Temperature  

NASA Technical Reports Server (NTRS)

One of the challenges of designing motors and alternators for use in nuclear powered space missions is accounting for the effects of radiation. Terrestrial reactor power plants use distance and shielding to minimize radiation damage but space missions must economize volume and mass. Past studies have shown that sufficiently high radiation levels can affect the magnetic response of hard and soft magnetic materials. Theoretical models explaining the radiation-induced degradation have been proposed but not verified. This paper reviews the literature and explains the cumulative effects of temperature, magnetic-load, and radiation-level on the magnetic properties of component materials. Magnetic property degradation is very specific to alloy choice and processing history, since magnetic properties are very much entwined with specific chemistry and microstructural features. However, there is basic theoretical as well as supportive experimental evidence that the negative impact to magnetic properties will be minimal if the bulk temperature of the material is less than fifty percent of the Curie temperature, the radiation flux is low, and the demagnetization field is small. Keywords: Magnets, Permanent Magnets, Power Converters, Nuclear Electric Power Generation, Radiation Tolerance.

Bowman, Cheryl L.

2013-01-01

437

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

NASA Astrophysics Data System (ADS)

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 Algorithms (GA) to optimize the diameter of its microchannels. In this work, a multi-objective GA scheme has been adopted to optimize the network topology against conflicting objectives, which include (i) optimizing the flow properties of the network (i.e., reducing the flow resistance of the network to a prescribed mass flow rate) and (ii) minimizing the impact of the network on the stiffness and strength of the resulting composite in terms of the void volume fraction associated with the presence of the microvascular network. The flow analysis of the network is performed based on the assumption of fully established Poiseuille flow in all segments of the network, leading to the classical proportionality relation between the pressure drop along a segment and the mass flow rate. The optimized structures resulting from the optimization can then be manufactured using an automated process ("robotic deposition") that involves the extrusion of a fugitive wax to define the network. Once manufactured, the computer-aided design can then be validated through a comparison with the results obtained from flow tests. This presentation focuses on the results of the optimization of an epoxy-based composite material containing a two-dimensional microvascular network.

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

2007-04-01

438

2006 Design Research Society . International Conference in Lisbon . IADE 1 Regarding Software as a Material of Design  

E-print Network

Indiana, United States eblevis@indiana.edu The Issue Design as a discipline has a long history, environments, and artifice that is informed by theories that range from engineering and cognitive psychology design as a distinct design discipline from other forms of design, it is also possible as hypothesis

Blevis, Eli

439

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

SciTech Connect

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.

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

1998-08-01

440

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

PubMed Central

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

Luo, Tianzhi; Kiick, Kristi L.

2013-01-01

441

Thermal control for space microelectronic equipment via pyroelectric material: Design, characterisation and experimental campaign  

NASA Astrophysics Data System (ADS)

In the last decades the development of new satellite platforms from a smaller to a bigger size goes in parallel with the development of the microelectronics equipment boarded on. Avionics, control systems and payloads equipment exploit the microelectronics in order to reduce the overall dimensions and masses and to increase the performances of each unit for the improvement of goals in each mission. A larger use of electronic elements with the relevant components increases the importance of a carefully equipment designed under different points of view. One of them is the thermal management. It is well known that the Joule Effect causes the heat overstocking which in turn reduces the efficiency of the electronic devices and increases the difficulties to manage the thermal power budget on board. A new design philosophy sees a possibility for a simpler and a more efficient thermal control on the use of the pyroelectric materials. Pyroelectrics are a "special" class of materials that demonstrates a spontaneous capacity to convert thermal fluxes in electrical charge and if applied on a "passive" structure they can "actively" reduce the heat overstocking. The electrical charge could be eventually stored for different purposes such as for instance the auto-feeding, or better the energy harvesting. With the reduction of the temperature of each component, and consequently with the reduction of the heat flux that flows through microelectronics, better efficiency and better performances are ensured. In this way the reliability is increased and the goals of the mission could be achieved easier and easier. In this paper the design of a thermal rig made up of pyroelectric devices and dummy electronics components in order to verify the thermo-electric conversion is presented. Furthermore an experimental campaign has been performed to validate the technology here introduced and the relevant results presented. In particular the characterisation of a typical aerospace pyroelectric material via scanning electron microscope (SEM) and a semi-quantitative analysis will be discussed. In order to verify the trustworthiness of the experimental campaign the results will be compared with the ones coming from an in-house-developed numerical code.

Monti, Riccardo; Gasbarri, Paolo; Lecci, Umberto

2012-12-01

442

Designing materials for energy storage with high power and energy density : LiFePO? cathode material  

E-print Network

LiFePO? has drawn a lot of attention as a cathode material in lithium rechargeable batteries because its structural and thermal stability, its inexpensive cost, and environmental friendliness meet the requirements of power ...

Kang, Byoungwoo

2010-01-01

443

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

NSDL National Science Digital Library

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.

Currie, Eddie; Doboli, Alex; Kane, Patrick; Van Ess, Dave

2010-03-05

444

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

Federal Register 2010, 2011, 2012, 2013

...Designation of an Expanded Ocean Dredged Material Disposal Site (ODMDS) off Fort Lauderdale...cooperation with the U.S. Army Corps of Engineers Jacksonville District (USACE), intends...in size, for the disposal of dredged material from the potential construction...

2011-05-09

445

Journal of Nuclear Materials, Volumes 367-370, 2007, 1586-1589 Designing Optimised Experiments for the International Fusion  

E-print Network

Journal of Nuclear Materials, Volumes 367-370, 2007, 1586-1589 Designing Optimised Experiments for the International Fusion Materials Irradiation Facility R. Kemp1 G.A. Cottrell2 and H.K.D.H. Bhadesia1 1 Department EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon., OX14 3DB, UK Abstract

Cambridge, University of

446

Comparing composite materials with structural steels in the design of the optical support structure of very large telescopes  

Microsoft Academic Search

The method of finite element analysis is used to study some candidate composite materials: carbon filter reinforced epoxy and glass fiber reinforced epoxy. These composites may have real applications in the design of the optical support structures of very large telescopes where stringent thermomechanical stability are needed. The lightweight property of these materials allows one to build very stiff members

Andrew Y. Cheng; Robert K. Li

1992-01-01

447

Effects of Design Variables on User Evaluation of Printed Materials Prepared for the Expanded Nutrition Education Program in Pennsylvania.  

ERIC Educational Resources Information Center

A research study investigated the effects of three design variables upon user evaluations of printed materials. Three handouts dealing with refrigeration, household pests, and germs were distributed to aides and low-income families participating in the Expanded Nutrition Education Program; these materials varied with respect to type size, presence…

Hayes, Kevin G.

448

Sustainable Design of Geopolymers - Integration of Economic and Environmental Aspects in the Early Stages of Material Development  

Microsoft Academic Search

Design of novel products is a complex, multi-level process. It may be divided into the two main phases of material and product development. Up to now, economic and ecological assessments have been carried out mainly after the development of materials. At that point of time, however, there is only a small degree of freedom to change the composition or process

Marcel Weil; Edgar Gasafi

449

Neutron and Synchrotron Radiation Studies for Designer Materials, Sustainable Energy and Healthy Lives  

NASA Astrophysics Data System (ADS)

Probably the most prolific use of large accelerators today is in the creation of bright beams of x-ray photons or neutrons. The number of scientific users of such sources in the US alone is approaching 10,000. I will describe the some of the major applications of synchrotron and neutron radiation and their impact on society. If you have AIDS, need a better IPOD or a more efficient car, or want to clean up a superfund site, you are benefitting from these accelerators. The design of new materials is becoming more and more dependent on structural information from these sources. I will identify the trends in applications which are demanding new sources with greater capabilities.

Gibson, J. Murray

2009-05-01

450

Design amphiphilic dipolar ?-systems for stimuli-responsive luminescent materials using metastable states  

NASA Astrophysics Data System (ADS)

?-Conjugated compounds that exhibit tunable luminescence in the solid state under external mechanical stimuli have potential applications in sensors and imaging devices. However, no rational designs have been proposed that impart these mechano-responsive luminescent properties to ?-conjugated compounds. Here we demonstrate a strategy for mechano-responsive luminescent materials by imparting amphiphilic and dipolar characteristics to a luminescent ?-conjugated system. The oligo(p-phenylenevinylene) luminophore with a didodecylamino group at one end and a tri(ethylene glycol) ester group at the other end yields segregated solid structures by separately aggregating its hydrophobic and hydrophilic moieties. The segregated structures force the molecules to align in the same direction, thereby generating a conflict between the side-chain aggregation and dipolar stabilization of the ?-system. Consequently, these metastable solid structures can be transformed through mechanical stimulation to a more stable structure, from a ?-? stacked aggregate to a liquid crystal and further to a crystalline phase with variable luminescence.

Yagai, Shiki; Okamura, Satoru; Nakano, Yujiro; Yamauchi, Mitsuaki; Kishikawa, Keiki; Karatsu, Takashi; Kitamura, Akihide; Ueno, Akira; Kuzuhara, Daiki; Yamada, Hiroko; Seki, Tomohiro; Ito, Hajime

2014-06-01

451

Design of Miniaturized Double-Negative Material for Specific Absorption Rate Reduction in Human Head  

PubMed Central

In this study, a double-negative triangular metamaterial (TMM) structure, which exhibits a resounding electric response at microwave frequency, was developed by etching two concentric triangular rings of conducting materials. A finite-difference time-domain method in conjunction with the lossy-Drude model was used in this study. Simulations were performed using the CST Microwave Studio. The specific absorption rate (SAR) reduction technique is discussed, and the effects of the position of attachment, the distance, and the size of the metamaterials on the SAR reduction are explored. The performance of the double-negative TMMs in cellular phones was also measured in the cheek and the tilted positions using the COMOSAR system. The TMMs achieved a 52.28% reduction for the 10 g SAR. These results provide a guideline to determine the triangular design of metamaterials with the maximum SAR reducing effect for a mobile phone. PMID:25350398

Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2014-01-01

452

Towards Designing E-learning Materials based on Multi Learner’s Styles  

E-print Network

Although each learner is provided at birth with a certain learning style specific to any of the three main ones, (Visual, Auditory and Kinesthetic). The ideal learning style remains to be a part or a mixture of all the three or any two of the three kinds. Some learners possess strong inclination, while others have a less effective mixture of two or the three common favored styles. The existing systems either follow Auditory, Visual or Kinesthetic type of learning or a static combination, but not a dynamic combination. In this research study, a proposal on a newly designed coursework for benefiting the students according to their preferred learning style and capabilities will be presented. The main goal of this proposed research study is to prepare a courseware material that fits the dynamic learning needs of all learner styles, (Visual, Auditory and Kinesthetic).

Buthaina Deeb; Universiti Tenaga Nasional (uniten; Zainuddin Bin Hassan

453

Design amphiphilic dipolar ?-systems for stimuli-responsive luminescent materials using metastable states.  

PubMed

?-Conjugated compounds that exhibit tunable luminescence in the solid state under external mechanical stimuli have potential applications in sensors and imaging devices. However, no rational designs have been proposed that impart these mechano-responsive luminescent properties to ?-conjugated compounds. Here we demonstrate a strategy for mechano-responsive luminescent materials by imparting amphiphilic and dipolar characteristics to a luminescent ?-conjugated system. The oligo(p-phenylenevinylene) luminophore with a didodecylamino group at one end and a tri(ethylene glycol) ester group at the other end yields segregated solid structures by separately aggregating its hydrophobic and hydrophilic moieties. The segregated structures force the molecules to align in the same direction, thereby generating a conflict between the side-chain aggregation and dipolar stabilization of the ?-system. Consequently, these metastable solid structures can be transformed through mechanical stimulation to a more stable structure, from a ?-? stacked aggregate to a liquid crystal and further to a crystalline phase with variable luminescence. PMID:24898172

Yagai, Shiki; Okamura, Satoru; Nakano, Yujiro; Yamauchi, Mitsuaki; Kishikawa, Keiki; Karatsu, Takashi; Kitamura, Akihide; Ueno, Akira; Kuzuhara, Daiki; Yamada, Hiroko; Seki, Tomohiro; Ito, Hajime

2014-01-01

454

Ratiometric optical oxygen sensing: a review in respect of material design.  

PubMed

The quantitative determination of oxygen concentration is essential for a variety of applications ranging from life sciences to environmental sciences. Optical oxygen sensing allows non-invasive measurements with biological objects, parallel monitoring of multiple samples, and imaging. In general, ratiometric optical oxygen sensing is more desirable, due to its advantages of selectivity, insensitivity to ambient or scattered light, and elimination of instrumental fluctuation. Moreover, it can provide the perceived colour change, which would be useful not only for the ratiometric method of detection but also for rapid visual sensing. Mainly focusing on material design for ratiometric measurement, this review describes the overall progress made in the past ten years on ratiometric optical ground-state triplet oxygen sensing and offers a critical comparison of various methods reported in the literature. It also provides a development blueprint for ratiometric optical oxygen sensing. PMID:22943050

Feng, Yan; Cheng, Jinghui; Zhou, Li; Zhou, Xiangge; Xiang, Haifeng

2012-11-01

455

Design of miniaturized double-negative material for specific absorption rate reduction in human head.  

PubMed

In this study, a double-negative triangular metamaterial (TMM) structure, which exhibits a resounding electric response at microwave frequency, was developed by etching two concentric triangular rings of conducting materials. A finite-difference time-domain method in conjunction with the lossy-Drude model was used in this study. Simulations were performed using the CST Microwave Studio. The specific absorption rate (SAR) reduction technique is discussed, and the effects of the position of attachment, the distance, and the size of the metamaterials on the SAR reduction are explored. The performance of the double-negative TMMs in cellular phones was also measured in the cheek and the tilted positions using the COMOSAR system. The TMMs achieved a 52.28% reduction for the 10 g SAR. These results provide a guideline to determine the triangular design of metamaterials with the maximum SAR reducing effect for a mobile phone. PMID:25350398

Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2014-01-01

456

Design and Synthesis of a New Layered Thermoelectric Material LaPbBiS3O.  

PubMed

A new quinary oxysulfide LaPbBiS3O was designed and successfully synthesized via a solid-state reaction in a sealed evacuated quartz tube. This material, composed of stacked NaCl-like [M4S6] (where M = Pb, Bi) layers and fluorite-type [La2O2] layers, crystallizes in the tetragonal space group P4/nmm with a = 4.0982(1) Å, c = 19.7754(6) Å, and Z = 2. Electrical resistivity and Hall effect measureme