Note: This page contains sample records for the topic negative-index material design from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

The science of negative index materials  

Microsoft Academic Search

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

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

2008-01-01

2

Development of AIM-Based Fast Solver for Efficient Design and Synthesis of Negative Index Materials.  

National Technical Information Service (NTIS)

This report presents a fast hybrid volume-surface integral equation approach for the computation of electromagnetic scattering from composite left- handed materials (LHM) such as split-ring resonators (SRR) with wires. The volume electric field integral e...

J. L. Li

2007-01-01

3

Design and applications of negative index metamaterials  

NASA Astrophysics Data System (ADS)

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

Lam, Tai Anh

4

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

PubMed

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

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

2008-08-01

5

Composite materials with giant anisotropy and negative index of refraction  

Microsoft Academic Search

We demonstrate that a nanostructured plasmonic composite material can show negative index of refraction at infrared and optical frequencies. In contrast to conventional negative refraction materials, our design does not require periodicity and thus is highly tolerant to fabrication defects. Moreover, since the proposed material is intrinsically non-magnetic (mu ? 1), its performance is not limited to proximity of a

Viktor A. Podolskiy; Leo A. Alekseyev; Evgenii E. Narimanov

2005-01-01

6

Origin of dissipative losses in negative index of refraction materials  

Microsoft Academic Search

Negative index of refraction materials have been postulated for many years but have only recently been realized in practice. In the microwave region these materials are constructed of rings and wires deposited on a dielectric substrate to form a unit cell. We have constructed, experimentally characterized, and simulated several of these structures operating in the 10–16 GHz range. The origin

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

2003-01-01

7

Origin of dissipative losses in negative index of refraction materials  

Microsoft Academic Search

Negative index of refraction materials have been postulated for many years but have only recently been realized in practice. In the microwave region these materials are constructed of rings and wires deposited on a dielectric substrate to form a unit cell. We have constructed, experimentally characterized, and simulated several of these structures operating in the 10-16 GHz range. The origin

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

2003-01-01

8

Photorealistic images of objects in effective negative-index materials  

Microsoft Academic Search

Using a ray-tracing approach, we calculate photorealistic images and simple movies of objects in a material with negative index of refraction. Our results show several surprising and drastic effects, for example reversal of apparent object velocity, extreme distortions of object shape, and even apparent loss of connectivity of simple objects. The material presented aims at giving both researchers and laymen

Gunnar Dolling; Martin Wegener; Stefan Linden; Christoph Hormann

2006-01-01

9

Numerical study of electromagnetic waves interacting with negative index materials  

NASA Astrophysics Data System (ADS)

We study numerically the electromagnetic scattering properties of structures with negative indices of refraction. To perform this analysis, we utilize a commercial finite-element based electromagnetic solver (HFSS, Ansoft), in which a negative index material can be formed from mesh elements whose permittivity and permeability are both negative. In particular, we investigate the expected transmission characteristics of a finite beam incident on negative index prisms and lenses. We also confirm numerically the predicted superlens effect of an image formed by a planar slab with index n=-1, using two subwavelength (ë/20) slits as objects.

Kolinko, Pavel; Smith, David R.

2003-04-01

10

Numerical study of electromagnetic waves interacting with negative index materials.  

PubMed

We study numerically the electromagnetic scattering properties of structures with negative indices of refraction. To perform this analysis, we utilize a commercial finite-element based electromagnetic solver (HFSS, Ansoft), in which a negative index material can be formed from mesh elements whose permittivity and permeability are both negative. In particular, we investigate the expected transmission characteristics of a finite beam incident on negative index prisms and lenses. We also confirm numerically the predicted superlens effect of an image formed by a planar slab with index n=-1, using two subwavelength (ë/20) slits as objects. PMID:19461776

Kolinko, Pavel; Smith, David

2003-04-01

11

Simulations of ferrite-dielectric-wire composite negative index materials  

Microsoft Academic Search

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

Frederic Rachford; Douglas Armstead; Vincent Harris; Carmine Vittoria

2007-01-01

12

Microwave Focusing Using Negative Index of Refraction Materials  

Microsoft Academic Search

We present experimental results testing the theoretical prediction that a flat slab of negative index material can act as a perfect lens, focusing propagating waves. Our data gives two-dimensional profiles of the electromagnetic field transmitted from a 10 GHz point source in a 2D waveguide through composite wire and split-ring resonator rectangular prisms. Prior experiments show that these structures have

Jeffrey Brock; Andrew Houck; Isaac Chuang

2003-01-01

13

Forward and backward propagation in positive and negative index materials  

NASA Astrophysics Data System (ADS)

Forward and backward propagation can both be modeled in terms ofWigner distributions or alternatively in terms of spatial frequency transfer functions. We use both formalisms to show that, for non-evanescent waves, forward propagation in a negative index material is equivalent to backward propagation in a positive index medium. We consider the implications of this fact for several specific problems, including imaging 3D objects, imaging through thin phase screens, Fresnel holography, and speckle.

Goodman, Joseph W.

2013-09-01

14

Loss compensated negative index material at optical wavelengths  

SciTech Connect

We present a computational approach, allowing for a self-consistent treatment of three-dimensional (3D) fishnet metamaterial operating at 710 nm wavelength coupled to a gain material incorporated into the nanostructure. We show numerically that loss-free negative index material is achievable by incorporating gain material inside the fishnet structure. The effective gain coefficient of the combined fishnet-gain system is much larger than its bulk counterpart and the figure-of-merit (FOM = | Re(n)/Im(n) |) increases dramatically with gain. Transmission, reflection, and absorption data, as well as the retrieved effective parameters, are presented for the fishnet structure with and without gain.

Fang, Anan; Huang, Zhixiang; Koschny, Thomas; Soukoulis, Costas M.

2012-05-20

15

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

16

Travelling wave solutions in negative index materials in the presence of external source  

NASA Astrophysics Data System (ADS)

Negative index materials (NIMs) are artificially designed materials which have attracted lot of interest due to their remarkable properties. In this work, we discuss some of the properties of NIMs and obtained travelling wave solutions for pulse propagation in NIMs in the presence of external source. The reported solutions are necessarily of the fractional-type containing trigonometric and hyperbolic functions.

Sharma, Vivek Kumar; Goyal, Amit; Kumar, C. N.; Goswamy, J.

2013-06-01

17

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

18

BAND STRUCTURES AND ABNORMAL BEHAVIOR OF ONE DIMENSIONAL PHOTONIC CRYSTAL CONTAINING NEGATIVE INDEX MATERIALS  

Microsoft Academic Search

Abstract—We have studied the optical properties,band structures and group velocities,of one dimensional photonic crystal (1-D PC) containing negative index materials using translational matrix method (TMM). The 1-D PC containing negative index materials is a periodic arrangement of positive index material (PIM) and negative index material (NIM). The observed group velocity of such structure is larger than the speed of light

Girijesh N. Pandey; Khem B. Thapa; Sanjeev Kumar Srivastava; Sant Prasad Ojha

2008-01-01

19

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

PubMed

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

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

2007-07-30

20

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

21

Are negative index materials achievable with surface plasmon waveguides? A case study of three plasmonic geometries.  

PubMed

We present a theoretical analysis of planar plasmonic waveguides that support propagation of positive and negative index modes. Particular attention is given to the modes sustained by metal-insulator-metal (MIM), insulator-metal-insulator (IMI), and insulator-insulator-metal (IIM) geometries at visible and near-infrared frequencies. We find that all three plasmonic structures are characterized by negative indices over a finite range of visible frequencies, with figures of merit approaching 20. Moreover, using finite-difference time-domain simulations, we demonstrate that visible-wavelength light propagating from free space into these waveguides can exhibit negative refraction. Refractive index and figure-of-merit calculations are presented for Ag/GaP and Ag/Si(3)N(4) - based structures with waveguide core dimensions ranging from 5 to 50 nm and excitation wavelengths ranging from 350 nm to 850 nm. Our results provide the design criteria for realization of broadband, visible-frequency negative index materials and transformation-based optical elements for two-dimensional guided waves. These geometries can serve as basic elements of three-dimensional negative-index metamaterials. PMID:19581993

Dionne, Jennifer A; Verhagen, Ewold; Polman, Albert; Atwater, Harry A

2008-11-10

22

Ultrashort Pulse Propagation in Negative Index Materials: From Negative Refraction to Nonlinear Pulse Propagation.  

National Technical Information Service (NTIS)

Negative index materials (NIMs) hold the promise for super lensing of electromagnetic radiation for applications in radar, THz, and possibly at optical frequencies. We have developed a new vector pulse propagation method that we use to study the electrody...

M. Scalora M. J. Bloemer C. M. Bowden G. D'Aguanno N. Mattiucci

2004-01-01

23

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

NASA Astrophysics Data System (ADS)

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

Petrin, A. B.

2013-09-01

24

Negative Index of Refraction in Anisotropic Nonmagnetic Materials  

Microsoft Academic Search

We analyze the possibility of negative refractive index and\\/or negative refraction of energy flow in a uniaxial nonmagnetic dielectric material. It is shown that an extraordinary p-polarized electromagnetic wave can exhibit a negative refraction provided the parallel (with respect to the optical axis) and perpendicular components of the permittivity have different signs. Such a situation can be encountered near phonon

V. Dvo?ák; P. Kužel

2006-01-01

25

Negative Index of Refraction in Anisotropic Nonmagnetic Materials  

Microsoft Academic Search

We analyze the possibility of negative refractive index and\\/or negative refraction of en- ergy flow in a uniaxial nonmagnetic dielectric material. It is shown that an extraordinary p-polarized electromagnetic wave can exhibit a negative refraction provided the parallel (with respect to the optical axis) and perpendicular components of the permittivity have different signs. Such a situation can be encountered near

V. DVO

26

Applicability of ferrimagnetic hosts to nanostructured negative index of refraction (left-handed) materials  

Microsoft Academic Search

There has been considerable interest generated by the demonstration of (epsilon) < 0, (mu) < 0 composite materials. These negative index of refraction materials, a subset of the class of materials labeled 'left-handed', possess two different arrays of resonant structures which separately give rise to negative (epsilon) and (mu) over the appropriate microwave frequency interval. Any attempt to significantly increase

Graeme Dewar

2002-01-01

27

Experimental determination and numerical simulation of the properties of negative index of refraction materials  

Microsoft Academic Search

Negative index of refraction materials have been postulated for many years but have only recently been realized in practice. In the microwave region these materials are constructed of rings and wires deposited on a dielectric substrate to form a unit cell. We have constructed, experimentally characterized and simulated several of these structures operating in the 10 - 15 GHz range.

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

2003-01-01

28

Application of DP-FETI domain decomposition method for the negative index of refraction materials  

Microsoft Academic Search

In this paper, NIM are modeled by a fast nonconforming dual primal-finite element tearing interconnecting (DP-FETI) domain decomposition method (DDM). We apply the DP-FETI-DDM method to model both positive and negative index materials, refer to as PIM and NIM. Since NIM are generally periodic in nature, the proposed method is capable of taking advantage of such periodicity and only requires

Kezhong Zhao; Marinos N. Vouvakis; Jin-Fa Lee

2005-01-01

29

Experimental determination and numerical simulation of the properties of negative index of refraction materials.  

PubMed

Negative index of refraction materials have been postulated for many years but have only recently been realized in practice. In the microwave region these materials are constructed of rings and wires deposited on a dielectric substrate to form a unit cell. We have constructed, experimentally characterized and simulated several of these structures operating in the 10 - 15 GHz range. Our simulations using Maxwell's Equations solvers have included wire arrays, ring arrays and assemblies of unit cells comprised of rings and wires. We find good agreement between the numerical simulations and experimental measurements of the scattering parameters and index of refraction. The procedure was to first model ring and wire structures on the unit cell level to obtain scattering parameters from which effective å, ì and n were retrieved. Next an assembled array of unit cells forming a 12 degrees wedge was used for the Snell's Law determination of the negative index of refraction. For the structure examined the computed value of n is within 20% of the one experimentally measured in the Snell's Law experiment from 13.6 to 14.8 GHz. PMID:19461780

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

2003-04-01

30

Focussing by Negative-Index Effect in Two-Dimensional Photonic Crystals in a High-Index-Contrast Material System  

Microsoft Academic Search

The paper presents a numerical and experimental study of focussing by the negative-index effect in two-dimensional photonic crystals in a high-index-contrast slab waveguide. The simulations and experiments are carried out at 21.5 GHz in a Rogers TMM10-(thermoset ceramic loaded plastic) teflon material system. It has about the same index contrast as the Si-SiO2 material system which is used for photonic

A. Rumberg; E. Dorner; M. Berroth

2006-01-01

31

Investigation of negative index in dispersive, chiral materials via contra-propagating velocities under second-order dispersion (GVD)  

NASA Astrophysics Data System (ADS)

Negative refractive index arises typically in metamaterials via multiple routes. One such avenue is the condition where the Poynting vector of the electromagnetic wave is in opposition to the group velocity in the material. An earlier work along this route in a chiral material led to the well-known result of requiring very large (non-realizable) chirality. Thereafter, a combination of chirality together with first-order dispersion was examined using plane wave electromagnetic analysis. To arrive at the conclusions in that approach, the three wave velocities (energy, group and phase) were derived under first-order dispersion in permittivity, permeability and chirality. Negative index in this approach was established under the condition of contra-propagating group and phase velocities. Regions of negative index were found analytically by assuming standard dispersive models (such as Condon). In this paper, we will re-visit the negative index problem under higher-order dispersion. In addition, we will re-examine the plane wave propagation model under parametric dispersion where each material parameter (?, ?, ?) is dispersively expanded up to the second order in frequency. Such a physical effect may be traced to group velocity dispersion (GVD) in the material. Field solutions are then obtained under the GVD effect, and extended to the evaluation of the energy, phase and group velocities.

Chatterjee, Monish R.; Algadey, Tarig

2013-09-01

32

Photonic approach to making a material with a negative index of refraction  

Microsoft Academic Search

An approach to producing a composite material with negative refraction index is demonstrated. It is shown that a photonic structure consisting of two dielectric materials, with positive and negative dielectric permittivities, can support electromagnetic surface waves which exhibit the unusual electromagnetic property of left handedness (or negative refraction index). Depending on the dielectric materials, these surface waves localized at the

Gennady Shvets

2003-01-01

33

Superconducting artificial materials with a negative permittivity, a negative permeability, or a negative index of refraction  

Microsoft Academic Search

Artificial materials are media made of inclusions such that the sizes and spacing of the inclusions is much smaller than the incident electromagnetic radiation. This allows a medium to act as an effective bulk medium to electromagnetic radiation. Artificial materials can be tailored to produce desired values of the permittivity, permeability, and index of refraction at specific frequencies. The applications

Michael Christopher Ricci

2007-01-01

34

Development of solid state materials with negative index of refraction and \\  

Microsoft Academic Search

We demonstrate that a photonic structure consisting of materials with positive and negative dielectric permittivity can exhibit left-handedness. Examples of plasmonic (Ag) and phononic (SiC) building blocks will be used. SiC is also attractive for a near-field \\

G. Shvets

2003-01-01

35

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

36

Relaxation in harmonic oscillator systems and wave propagation in negative index materials  

NASA Astrophysics Data System (ADS)

This dissertation is divided up into two parts, each examining a distinct theme. The first part of our work concerns itself with open quantum systems and the relaxation phenomena arising from the repeated application of an interaction Hamiltonian on systems composed of quantum harmonic oscillators. For the second part of our work, we shift gears and investigate the wave propagation in left-handed media, or materials with simultaneously negative electric permeability epsilon and magnetic permeability mu. Each of these two parts is complete within its own context. In the first part of this dissertation, we introduce a relaxation-generating when an interaction Hamiltonian is repeatedly applied to bipartite harmonic oscillator systems for some characteristic time interval tau. The two important time scales which enter our results are discussed in detail. We show that the relaxation time obtained by the application of this repeated interaction scheme is proportional to both the strength of interaction and to the characteristic time interval tau. Through discussing the implications of our model, we show that, for the case where the oscillator frequencies are equal, the initial Maxwell-Boltzmann distributions of the uncoupled parts evolve to a new Maxwell-Boltzmann distribution through a series of transient Maxwell-Boltzmann distributions, or quasi-stationary, non-equilibrium states. We further analyze the case in which the two oscillator frequencies are unequal and show how the application of the same model leads to a non-thermal steady state. The calculations are exact and the results are obtained through an iterative process, without using perturbation theory. In the second part of this dissertation, we examine the response of a plane wave incident on a at surface of a left-handed material, a medium characterized by simultaneously negative electric permittivity epsilon and magnetic permeability mu. We do this by solving Maxwell's equations explicitly. In the literature up to date, it has been assumed that negative refractive materials are necessarily frequency dispersive. We propose an alternative to this assumption by suggesting that the requirement of positive energy density can be relaxed, and discuss the implications of such a proposal. More specifically, we show that once negative energy solutions are accepted, the requirement for frequency dispersion is no longer needed. We further argue that, for the purposes of discussing left-handed materials, the use of group velocity as the physically significant quantity is misleading, and suggest that any discussion involving it should be carefully reconsidered.

Chimonidou, Antonia

37

Negative index metamaterials in magnetic composites  

Microsoft Academic Search

In this paper, we will review some works on negative index metamaterials in magnetic composites, basically based on our recent works. First, we explore the condition of the existence of negative index meta-materials made of magnetic materials. We will point out that the left-handed materials in the magnetic materials are closely related to the wave polarization and magnetic damping. Then,

Rui-xin Wu

2008-01-01

38

Design and Free-Space Measurements of Broadband, Low-Loss Negative-Permeability and Negative-Index Media  

Microsoft Academic Search

We present the design and measurement of broad- band, volumetric negative-permeability and negative-refrac- tive-index (NRI) media. Both of these media are fabricated using standard printed-circuit-board techniques and operate at X-band frequencies. The S-parameters of four-cell slabs of the negative-permeability and NRI media are measured, and the material parameters of the NRI lens are extracted. The four-cell-thick NRI lens exhibits a

Scott Michael Rudolph; Carl Pfeiffer; Anthony Grbic

2011-01-01

39

Experimental demonstration of negative index of refraction  

Microsoft Academic Search

We introduce an improved and simplified structure made of periodic arrays of pairs of H-shaped metallic wires that offer a potentially simpler approach in building negative-index materials. Using simulations and microwave experiments, we have investigated the negative-index n properties of these structures. We have measured experimentally both the transmittance and the reflectance properties and found unambiguously that a negative refractive

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

2006-01-01

40

Infrared magnetic and negative-index metamaterials  

NASA Astrophysics Data System (ADS)

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

Zhang, Shuang

41

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

42

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

43

Periodic layered waveguide with negative index of refraction  

Microsoft Academic Search

The authors demonstrate that a negative index of refraction can exist in a periodic layered waveguide composed of natural materials with either permittivity or permeability negative. They find that the negative index depends on component materials, their configurations, and working modes of the waveguide. In the long wave limit, the expressions of the effective permeability and permittivity of the waveguide

Rui-Xin Wu; Tianen Zhao; Ping Chen; Jie Xu; Xinyi Ji

2007-01-01

44

Negative index of refraction and distributed Bragg reflectors  

Microsoft Academic Search

The Bragg regime shifts when conventional materials in a multilayer distributed Bragg reflector (DBR) are replaced by artificial materials with the so-called negative index of refraction. This provides an avenue for characterizing the latter class of materials.

Jaline Gerardin; Akhlesh Lakhtakia

2002-01-01

45

Structures with negative index of refraction  

Microsoft Academic Search

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

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

2011-01-01

46

Simulation and testing of a graded negative index of refraction lens  

Microsoft Academic Search

A gradient index (GRIN) lens using a negative index of refraction material (NIM) has been designed and tested. The GRIN lens was fabricated using a NIM slab with a variable index of refraction perpendicular to the propagation direction. Ray tracing calculations based on the isotropic Eikonal equation determined the index of refraction gradient required for a given focal length. An

R. B. Greegor; C. G. Parazzoli; J. A. Nielsen; M. A. Thompson; M. H. Tanielian; D. R. Smith

2005-01-01

47

From scattering parameters to Snell's law: a subwavelength near-infrared negative-index metamaterial.  

PubMed

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 et al., Phys. Rev. E 71, 036617 (2005)]. Furthermore, these general rules allow for the design of a subwavelength near-infrared negative-index material, where the negative refractive index is verified by band calculations to be a bulk property. Full-wavelength simulations of prisms consisting of these unit cells suggest behavior consistent with Snell's law in the negative-index regime. PMID:19113786

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

2008-12-31

48

The Role of Multiferroics in the Negative Index of Refraction  

Microsoft Academic Search

We explore the possibility of realizing intrinsic far infrared negative index materials (NIM) in multiferroic crystals (crystals simultaneously possessing a ferroelectric and ferromagnetic phase) possessing electric and magnetic dipole resonances with nearby resonance frequencies, or overlapping regions of negative permittivity and permeability. We demonstrate the functionality of such a material using finite difference time domain simulations. In order to motivate

David W. Ward; Eric Statz; Kevin J. Webb; Keith A. Nelson

2004-01-01

49

Evidence of negative-index refraction in nonlinear chemical waves.  

PubMed

The negative index of refraction of nonlinear chemical waves has become a recent focus in nonlinear dynamics researches. Theoretical analysis and computer simulations have predicted that the negative index of refraction can occur on the interface between antiwaves and normal waves in a reaction-diffusion (RD) system. However, no experimental evidence has been found so far. In this Letter, we report our experimental design in searching for such a phenomenon in a chlorite-iodide-malonic acid (CIMA) reaction. Our experimental results demonstrate that competition between waves and antiwaves at their interface determines the fate of the wave interaction. The negative index of refraction was only observed when the oscillation frequency of a normal wave is significantly smaller than that of the antiwave. All experimental results were supported by simulations using the Lengyel-Epstein RD model which describes the CIMA reaction-diffusion system. PMID:21635131

Yuan, Xujin; Wang, Hongli; Ouyang, Qi

2011-05-06

50

Left handed metamaterials with negative index of refraction  

Microsoft Academic Search

Summary form only given. The author presents an introduction to the design and physical consequences of metamaterials with a frequency band with simultaneous negative permittivity and permeability. Negative index of refraction at microwave frequencies, and novel methods of construction are discussed.

S. Schultz

2002-01-01

51

Performance of a negative index of refraction lens  

Microsoft Academic Search

A plano-concave lens with negative index of refraction has been designed and fabricated. Such lenses have been postulated for many years, but only recently has their realization been made possible through improved simulation and fabrication procedures. We report here the simulation, fabrication, and performance of such a lens. The lens images the source field and reproduces the results of standard

C. G. Parazzoli; R. B. Greegor; J. A. Nielsen; M. A. Thompson; K. Li; A. M. Vetter; M. H. Tanielian; D. C. Vier

2004-01-01

52

Radiation pressure and photon momentum in negative-index media  

NASA Astrophysics Data System (ADS)

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 ?? /? and the group refractive index ng of the material (both positive entities), and not the phase refractive index n =??? , 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, because it violates the conservation laws.

Mansuripur, Masud; Zakharian, Armis R.

53

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

54

Coated nonmagnetic spheres with a negative index of refraction at infrared frequencies  

Microsoft Academic Search

A three-dimensional lattice of micron-scale coated spheres is shown to have an isotropic negative index of refraction at infrared frequencies. The materials used are entirely non-magnetic. The Mie scattering theory of the constituent spheres is used in the effective medium theory. The physical mechanisms and procedures are presented in the design of a negative effective permeability with solid polaritonic spheres,

Mark S. Wheeler; J. Stewart Aitchison; Mohammad Mojahedi

2006-01-01

55

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

56

Measured Polarization Response of Negative Index Metamaterial.  

National Technical Information Service (NTIS)

The geometrical anisotropy and bi-anisotropy of a split ring and post type metamaterial is studied by free space microwave measurements in a frequency band near 13.5 GHz where it exhibits negative index of refraction. The orientation of the linearly polar...

A. J. Drehman B. W. Turchinetz E. E. Crisman J. S. Derov S. R. Best

2005-01-01

57

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

NASA Astrophysics Data System (ADS)

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 the negative refractive index is verified by band calculations to be a bulk property. Full-wavelength simulations of prisms consisting of these unit cells suggest behavior consistent with Snell’s law in the negative-index regime.

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

2008-12-01

58

Metamaterials with gradient negative index of refraction.  

PubMed

We propose a new metamaterial with a gradient negative index of refraction, which can focus a collimated beam of light coming from a distant object. A slab of the negative refractive index metamaterial has a focal length that can be tuned by changing the gradient of the negative refractive index. A thin metal film pierced with holes of appropriate size or spacing between them can be used as a metamaterial with the gradient negative index of refraction. We use finite-difference time-domain calculations to show the focusing of a plane electromagnetic wave passing through a system of equidistantly spaced holes in a metal slab with decreasing diameters toward the edges of the slab. PMID:17912287

Pinchuk, Anatoliy O; Schatz, George C

2007-10-01

59

The Role of Multiferroics in the Negative Index of Refraction  

Microsoft Academic Search

We explore the possibility of realizing intrinsic far infrared negative index\\u000amaterials (NIM) in multiferroic crystals (crystals simultaneously possessing a\\u000aferroelectric and ferromagnetic phase) possessing electric and magnetic dipole\\u000aresonances with nearby resonance frequencies, or overlapping regions of\\u000anegative permittivity and permeability. We demonstrate the functionality of\\u000asuch a material using finite difference time domain simulations. In order to\\u000amotivate

David W. Ward; Eric Statz; Kevin J. Webb; Keith A. Nelson

2004-01-01

60

Low-loss single-layer metamaterial with negative index of refraction at visible wavelengths  

Microsoft Academic Search

We present a structure exhibiting a negative index of refraction at visible or near infrared frequencies using a single metal layer. This contrasts with recently developed structures based on metal-dielectric-metal composites. The proposed metamaterial consists of periodically arranged thick stripes interacting with each other to give rise to a negative permeability. Improved designs that allow for a negative index for

C. García-Meca; R. Ortuño; R. Salvador; A. Martínez; J. Martí

2007-01-01

61

Negative index of refraction, perfect lenses and transformation optics - some words of caution  

Microsoft Academic Search

In this paper we show that a negative index of refraction is not a direct implication of transformation optics with orientation-reversing diffeomorphisms. Rather, a negative index appears due to a specific choice of sign freedom. Furthermore, we point out that the transformation designed lens, which relies on the concept of spacetime folding, does not amplify evanescent modes, in contrast to

Luzi Bergamin; Alberto Favaro

2010-01-01

62

Negative index metamaterials and metaspacers for optical frequencies  

NASA Astrophysics Data System (ADS)

Metamaterials are artificial materials that exhibit properties, such as negative index of refraction, that are not possible through natural materials. Due to many potential applications of negative index metamaterials, significant progress in the field has been observed in the last decade. However, achieving negative index at visible frequencies is a challenging task. Generally, fishnet metamaterials are considered as a possible route to achieve negative index in the visible spectrum. However, so far no metamaterial has been demonstrated to exhibit simultaneously negative permittivity and permeability (double-negative) beyond the red region of the visible spectrum. This study is mainly focused on achieving higher operating frequency for low-loss, double-negative metamaterials. Two double-negative metamaterials have been proposed to operate at highest reported frequencies. The first proposed metamaterial is based on the interaction of surface plasmon polaritons of a thin metal film with localized surface plasmons of a metallic array placed close to the thin film. It is demonstrated that the metamaterial can easily be scaled to operate at any frequency in the visible spectrum as well as possibly to the ultraviolet spectrum. Furthermore, the underlying physical phenomena and possible future extensions of the metamaterial are also investigated. The second proposed metamaterial is a modification to the so-called fishnet metamaterial. It has been demonstrated that this 'modified fishnet' exhibits two double-negative bands in the visible spectrum with highest operating frequency in the green region with considerably high figure of merit. In contrast to most of the fishnet metamaterials proposed in the past, behavior of this modified fishnet is independent of polarization of the incident field. In addition to the two negative index metamaterials proposed in this study, the use of metamaterial as a spacer, named as metaspacer, is also investigated. In contrast to naturally available dielectric spacers used in microfabrication, metaspacers can be realized with any (positive or negative) permittivity and permeability. As an example, the use of a negative index metaspacer in place of the dielectric layer in a fishnet metamaterial is investigated. It is shown that fishnet based on negative index metaspacer gives many improved optical properties over the conventional fishnet such as wider negative index band, higher figure of merit, higher optical transmission and stronger magnetic response. In addition to the improved properties, following interesting features were observed in the metaspacer based fishnet metamaterial. At the resonance frequency, the shape of the permeability curve was `inverted' as compared to that for conventional fishnet metamaterial. Furthermore, dependence of the resonance frequency on the fishnet geometry was also reversed. Moreover, simultaneously negative group and phase velocities were observed in the low-loss region of the metaspacer based fishnet metamaterial. Due to interesting features observed using metaspacer, this study will open a new horizon for the metamaterial research.

Aslam, Muhammad Imran

63

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

64

Ferromagnetic metamaterial with tunable negative index of refraction  

Microsoft Academic Search

We investigate the index of refraction of the ferromagnetic metamaterial, which consists of periodic layered ferrite and semiconductor or metallic mesh. We find that the metamaterial has the negative index; the frequency range and magnitude of the negative index are tunable in applied magnetic fields. The frequency range of the negative index shifts to higher frequencies as the applied magnetic

Da-Yong Zou; Ai-Min Jiang; Rui-Xin Wu

2010-01-01

65

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

66

Low-loss single-layer metamaterial with negative index of refraction at visible wavelengths.  

PubMed

We present a structure exhibiting a negative index of refraction at visible or near infrared frequencies using a single metal layer. This contrasts with recently developed structures based on metal-dielectric-metal composites. The proposed metamaterial consists of periodically arranged thick stripes interacting with each other to give rise to a negative permeability. Improved designs that allow for a negative index for both polarizations are also presented. The structures are numerically analyzed and it is shown that the dimensions can be engineered to shift the negative index band within a region ranging from telecommunication wavelengths down to blue light. PMID:19547274

García-Meca, C; Ortuño, R; Salvador, R; Martínez, A; Martí, J

2007-07-23

67

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

68

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

2010-04-18

69

Evidence of Negative-Index Refraction in Nonlinear Chemical Waves  

Microsoft Academic Search

The negative index of refraction of nonlinear chemical waves has become a recent focus in nonlinear dynamics researches. Theoretical analysis and computer simulations have predicted that the negative index of refraction can occur on the interface between antiwaves and normal waves in a reaction-diffusion (RD) system. However, no experimental evidence has been found so far. In this Letter, we report

Xujin Yuan; Hongli Wang; Qi Ouyang

2011-01-01

70

Periodic ferrite semiconductor layered composite with negative index of refraction  

Microsoft Academic Search

We have studied the index of refraction of periodic layered semiconductor-ferrite composite. Both the transmission matrix analysis and full-wave simulations confirm the existence of a negative index of refraction in the composite. We find that the magnitude of the negative index of refraction and its frequency range depend on the ratio of the semiconductor and ferrite layer thicknesses and the

Rui-Xin Wu; Tianen Zhao; John Q. Xiao

2007-01-01

71

Wave packet incident on negative-index media  

Microsoft Academic Search

This paper presents a study of the refraction and reflection of a wave packet in time and space at the plane boundary between free space and a negative index medium (NIM). We derive an analytic asymptotic expression that shows negative refraction at the angle predicted by the negative index evaluated at the center frequency with a speed of propagation in

John Rhodes Thomas; Akira Ishimaru

2005-01-01

72

Effect of negative index of refraction in the propagation of electromagnetic waves  

Microsoft Academic Search

Consider a material slab situated between two half free spaces. An electromagnetic waves is obliquely incident on it. We investigate the effect of index of refraction of the material in the transmission of electromagnetic waves. We study three cases of the material: real positive index of refraction, real negative index of refraction and the refractive index is a function of

Muin F. Ubeid; Mohammed M. Shabat

2010-01-01

73

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

PubMed

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

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

2003-03-11

74

Structures with negative index of refraction  

Microsoft Academic Search

We review recent progress in the investigation of man made composites which exhibit negative refrac- tion of the electromagnetic waves. Results for both left-handed materials (LHM) and photonic crystals are presented. Experiments on LHM are mostly done in the microwave regime, while on photonic crystals can be performed in the optical or the far-infrared regime.

Peter Markos; C. M. Soukoulis

2003-01-01

75

Full wave simulations of coated spheres with negative index of refraction at infrared frequencies  

Microsoft Academic Search

In this work we have successfully performed 3D full wave simulations of coated spheres. Retrieved effective material properties shows negative index of refraction similar to earlier analytical results except for some quantitative differences. The next step is to explore metamaterial property sensitivity to intrinsic material properties and fabrication tolerance.

T. A. Lam; Y. Kuga

2007-01-01

76

Grating-Induced Dual Mode Couplings in the Negative-Index Slab Waveguide  

Microsoft Academic Search

In a slab waveguide where negative-index materials are adopted as a core layer, we show that a single-period grating can act as both a Bragg reflector and a transmission grating, which enables us to achieve dual-wavelength mode couplings via a single grating.

Kyoung-Youm Kim; Il-Min Lee; Byoungho Lee

2009-01-01

77

Negative Index Metamaterials at Optical Frequencies: Theory and Experiment  

NASA Astrophysics Data System (ADS)

Pafomov and Veselago showed in 1950-60s that negative refraction should occur in homogeneous media with simultaneously negative dielectric permittivity and magnetic permeability, ?<0, ?<0. Pendry (2000) speculated that the ideal Veselago lens can produce sub- wavelength resolution. We find a strong effect of surfaces on resolution limit and nontrivial relation of subwavelength imaging to EM ``softness'' of the lens [1]. We have designed the metamaterial by means of FDTD modeling, which is a stack of metallic films with periodic hole arrays separated by dielectric layers (called ``fishnet'', FN) to work at IR wavelengths ?=1.5- 1.6 ?m. The FN samples have been fabricated by nanoimprint lithography[2]. The transmission and reflectance characteristics of the samples have been measured by laser spectroscopic ellipsometry and showed unambiguously that the FN supports the ``backward'' waves and have overall negative index of refraction at IR frequencies. We also show that single layers of FN structure have positive index. We also address the questions of countering losses by using gain medium, limits sub-wavelength resolution, and focusing. 1. A.M. Bratkovsky, A.Cano, and A.P. Levanyuk, Appl. Phys. Lett. 87, 103507 (2005). 2. W. Wu et al., cond-mat/0610352.

Ponizovskaya, E.; Bratkovsky, A. M.

2007-03-01

78

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

Microsoft Academic Search

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

E. L. Fertman; A. B. Beznosov

2011-01-01

79

Negative index of refraction, spacetime folding and perfect imaging in transformation optics  

Microsoft Academic Search

Negative index of refraction has become an accepted part of transformation optics, which is encountered in transformations that change the orientation of the manifold. Based on this concept, various designs of perfect lenses have been proposed, which all rely on a folding of space or spacetime, where the maps from electromagnetic space to laboratory space are multi-valued. Recently, a new

Luzi Bergamin

2009-01-01

80

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

81

Symmetry Breaking and Optical Negative Index of Closed Nanorings  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

82

Negative Index Meta-Devices Imaging and Engineering Concerns  

Microsoft Academic Search

A Fourier spectrum theoretical model is applied to characterize the performance of a negative- index metamaterial slab. It is demonstrated that to provide a high-resolution imaging one needs to amplify the evanescent fields emanating from the source and at the same time tailor the phase of the propagating waves. Balancing these two important features will offer the high-performance imaging in

Akram Ahmadi; Hossein Mosallaei

83

Negative index of refraction in artificial chiral materials  

Microsoft Academic Search

A new class of negative refractive-index metamaterials made of metallic spheres arranged in a three-dimensional lattice of helicoidal symmetry is reported. The studied metamaterial possesses several frequency bands which give rise to negative refraction. The proposed structures constitute a viable solution to realizing optical metamaterials since they can exhibit negative refraction in the frequency region of the surface-plasmon excitations of

Vassilios Yannopapas

2006-01-01

84

Negative index of refraction: A subclass of electromagnetically metamorphic materials  

Microsoft Academic Search

Electromagnetic metamorphism is defined as the complete transformation of a scattering object of fixed shape and dimensions from one electromagnetic state such as from a perfect electric conductor (PEC) to a distinctly different state such as a perfect magnetic conductor. At a single frequency every scatterer has five metamorphic states. All smooth scattering objects regardless of shape exhibit a similar

Yunhong Liu; Nicólaos G. Alexópoulos

2006-01-01

85

Experimental Verification of an Optical Negative-Index material  

Microsoft Academic Search

Comprehensive studies for a periodic array of gold nanorod pairs demonstrate its unique optical properties, including a negative refractive index in the optical range. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

V. P. Drachev; W. Cai; H. K. Yuan; A. K. Sarychev; A. V. Kildishev; G. Klimeck

2005-01-01

86

An approach to achieving a negative index of refraction using coincident resonances  

Microsoft Academic Search

A novel method of achieving a negative index of refraction in the far-infrared region using intrinsic material properties is proposed. SrTiO3 has a dielectric resonance at ?100 cm?1 that can be lowered by lowering the temperature or with Ba doping. NiO has an antiferromagnetic resonance at ?35 cm?1 that can be raised with an applied field or with Co doping.

S D Kirby; M Lee; R B van Dover

2007-01-01

87

Numerical simulations of negative-index refraction in a lamellar composite with alternating single negative layers  

Microsoft Academic Search

Negative-index refraction is demonstrated in a lamellar composite with epsilon-negative (ENG) and mu-negative (MNG) materials stacked alternatively. Based on the effective medium approximation, simultaneously negative effective permittivity and permeability of such a lamellar composite are obtained theoretically and further proven by full-wave simulations. Consequently, the renowned left-handed metamaterial comprising split ring resonators and wires is interpreted as an analogy of

Zheng-Gao Dong; Shi-Ning Zhu; Hui Liu

2006-01-01

88

An approach to achieving a negative index of refraction using coincident resonances  

Microsoft Academic Search

A novel method of achieving a negative index of refraction in the far-infrared region using intrinsic material properties is proposed. SrTiO3 has a dielectric resonance at ~100 cm-1 that can be lowered by lowering the temperature or with Ba doping. NiO has an antiferromagnetic resonance at ~35 cm-1 that can be raised with an applied field or with Co doping.

S. D. Kirby; M. Lee; R. B. van Dover

2007-01-01

89

Dynamics of evanescent matter waves in negative-index media  

Microsoft Academic Search

Semi-evanescent and evanescent matter waves produced by an atom wave packet impinging on a repulsive barrier can be back-refracted and reconstructed by the application of negative-index 'comoving' potential pulses. One shows that those collapses and revivals generate a matter wave confined on both sides of the barrier border ('surface matter wave') and should be observable via the retardation of atom

M. Hamamda; V. Bocvarski; F. Perales; J. Baudon; G. Dutier; C. Mainos; M. Boustimi; M. Ducloy

2010-01-01

90

Positive phase evolution of waves propagating along a photonic crystal with negative index of refraction.  

PubMed

We analyze propagation of electromagnetic waves in a photonic crystal at frequencies at which it behaves as an effective medium with a negative index in terms of refraction at its interface with free space. We show that the phase evolution along the propagation direction is positive, despite the fact that the photonic crystal displays negative refraction following Snell's law, and explain it in terms of the Fourier components of the Bloch wave. Two distinct behaviors are found at frequencies far and close to the band edge of the negative-index photonic band. These findings contrast with the negative phase evolution that occurs in left-handed materials, so care has to be taken when applying the term left-handed to photonic crystals. PMID:19529372

Martínez, Alejandro; Martí, Javier

2006-10-16

91

Negative-index metamaterial with polymer-embedded wire-pair structures at terahertz frequencies.  

PubMed

Experimental demonstrations of metamaterials with negative index of refraction have been limited to microwave and IR frequencies. In this work, a freestanding multilayer thin-film metamaterial showing a strong negative index of refraction at terahertz frequencies is fabricated and characterized. The metamaterial consists of periodically arranged H-shaped wire-pair resonant structures separated by a 14.5-microm-thick and enclosed between two 26-microm-thick layers of benzocyclobutene polymer. Complex reflection and transmission parameters of the metamaterial are measured via terahertz time-domain spectroscopy and are used for the extraction of refractive material properties. Our results show good agreement with finite element field simulations. PMID:19015708

Awad, Mohammad; Nagel, Michael; Kurz, Heinrich

2008-11-15

92

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

PubMed

Negative-index metamaterials (NIMs) are engineered structures with optical properties that cannot be obtained in naturally occurring materials. Recent work has demonstrated that focused ion beam and layer-by-layer electron-beam lithography can be used to pattern the necessary nanoscale features over small areas (hundreds of µm(2)) for metamaterials with three-dimensional layouts and interesting characteristics, including negative-index behaviour in the optical regime. A key challenge is in the fabrication of such three-dimensional NIMs with sizes and at throughputs necessary for many realistic applications (including lenses, resonators and other photonic components). We report a simple printing approach capable of forming large-area, high-quality NIMs with three-dimensional, multilayer formats. Here, a silicon wafer with deep, nanoscale patterns of surface relief serves as a reusable stamp. Blanket deposition of alternating layers of silver and magnesium fluoride onto such a stamp represents a process for 'inking' it with thick, multilayer assemblies. Transfer printing this ink material onto rigid or flexible substrates completes the fabrication in a high-throughput manner. Experimental measurements and simulation results show that macroscale, three-dimensional NIMs (>75 cm(2)) nano-manufactured in this way exhibit a strong, negative index of refraction in the near-infrared spectral range, with excellent figures of merit. PMID:21642984

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

2011-06-05

93

Materials, bicycles, and design  

NASA Astrophysics Data System (ADS)

If the selection of materials is to be integrated into engineering design, a procedure is needed to identify, from among the enormous range of materials, the subset which most closely meets the design requirements. The elements of such a procedure are here described and illustrated by using it to select materials for bicycle frames.

Ashby, M. F.

1995-02-01

94

Materials, Bicycles, and Design  

NASA Astrophysics Data System (ADS)

If the selection of materials is to be integrated into engineering design, a procedure is needed to identify, from among the enormous range of materials, the subset which most closely meets the design requirements. The elements of such a procedure are here described and illustrated by using it to select materials for bicycle frames.

Ashby, M. F.

1995-12-01

95

Materials by Design: Cybersteels  

Microsoft Academic Search

A systems approach to the computational design of materials as dynamic hierarchical structures has been pioneered by the multi-institutional Steel Research Group centered at Northwestern University. Integrating process\\/structure\\/property\\/performance relations, the approach combines materials science, applied mechanics and quantum physics. Materials and design services based on the methods, tools and databases developed are being commercialized by QuesTek, employing QuesTek's Computational Materials

Hern-Jeng Jou

2001-01-01

96

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

PubMed

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

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

2010-11-23

97

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

PubMed

We experimentally demonstrate a low-loss multilayered metamaterial exhibiting a double-negative refractive index in the visible spectral range. To this end, we exploit a second-order magnetic resonance of the so-called fishnet structure. The low-loss nature of the employed magnetic resonance, together with the effect of the interacting adjacent layers, results in a figure of merit as high as 3.34. A wide spectral range of negative index is achieved, covering the wavelength region between 620 and 806 nm with only two different designs. PMID:21405495

García-Meca, Carlos; Hurtado, Juan; Martí, Javier; Martínez, Alejandro; Dickson, Wayne; Zayats, Anatoly V

2011-02-11

98

Experimental verification of a negative index of refraction.  

PubMed

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 beam through a prism fabricated from this material, we determine the effective n, appropriate to Snell's law. These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root of epsilon.mu for the frequencies where both the permittivity (epsilon) and the permeability (mu) are negative. Configurations of geometrical optical designs are now possible that could not be realized by positive index materials. PMID:11292865

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

2001-04-01

99

Optimizing low loss negative index metamaterial for visible spectrum using differential evolution.  

PubMed

A novel negative index metamaterial design methodology for the visible spectrum with low losses was presented in this paper. A robust differential evolution (DE) was employed to optimize the metamaterial design to achieve a desired set of values for the index of refraction. By using numerical simulation of a wedge-shaped model and S-parameter retrieval method, we found that the DE-designed optimal solution can exhibit a low loss LH frequency band with simultaneously negative values of effective permittivity and permeability at the violet-light wavelength of 408 nm, and the figure of merit is 15.2, that means it may have practical applications because of its low loss and high transmission. Therefore, the design methodology presented in this paper is a very convenient and efficient way to pursue a novel metamaterial with desired electromagnetic characteristics in the visible spectrum. PMID:21716393

Zhao, Yongxiang; Chen, Fei; Shen, Qiang; Liu, Qiwen; Zhang, Lianmeng

2011-06-01

100

On the constitutive relations of G-chiral media and the possibility to realize negative-index media  

Microsoft Academic Search

Gyro-chiral (G-chiral) media of different constitutive re- lations are studied as potential materials to realize the negative-index material (NIM). G-chiral media are believed to have advantages over chiral media: negative refractive index and backward waves can be achieved without requiring the permittivity and permeability to be quite small at working frequency. The gyrotropic parameters favor the real- ization of NIM

Cheng-Wei Qiu; Hai-Ying Yao; Saïd Zouhdi; Le-Wei Li; Mook-Seng Leong

2006-01-01

101

Tunability of graded negative index-based photonic crystal lenses for fine focusing  

NASA Astrophysics Data System (ADS)

Graded negative refractive index-based photonic crystal (PC) lenses are designed by gradually modifying the sizes of air holes along the transverse direction for focusing the incident plane wave. To study the tunability of the graded negative index-based PC, we introduce filling factor A, gradually tune the filling factor, and use the finite-difference and time-domain (FDTD) algorithm for numerical calculation. Our calculation results indicate that the focal length and the spot size increase with A increasing. For the same A value, the focal length of a PC with elliptical air holes is the longest, and those of PC with square and rectangular air holes are the shortest. Moreover, when the focal length is greater than 1 ?m, the focal parameters of the PC are highly insensitive to the variation of A. When the focal length is less than 1 ?m, the PC lenses have higher transmittances and all well focus with a beam spot size breaking the diffraction limit. This feature possibly makes the graded negative index-based PC lenses have some new applications in optoelectronic systems.

Jin, Lei; Zhu, Qing-Yi; Fu, Yong-Qi

2013-09-01

102

Metallo-dielectric core-shell nanospheres as building blocks for optical three-dimensional isotropic negative-index metamaterials  

NASA Astrophysics Data System (ADS)

Materials showing electromagnetic properties that are not attainable in naturally occurring media, so-called metamaterials, have been lately, and still are, among the most active topics in optical and materials physics and engineering. Among these properties, one of the most attractive ones is the sub-diffraction resolving capability predicted for media having an index of refraction of -1. Here, we propose a fully three-dimensional, isotropic metamaterial with strong electric and magnetic responses in the optical regime, based on spherical metallo-dielectric core-shell nanospheres. The magnetic response stems from the lowest, magnetic-dipole resonance of the dielectric shell with a high refractive index, and can be tuned to coincide with the plasmon resonance of the metal core, responsible for the electric response. Since the response does not originate from coupling between structures, no particular periodic arrangement needs to be imposed. Moreover, due to the geometry of the constituents, the metamaterial is intrinsically isotropic and polarization independent. It could be realized with current fabrication techniques with materials such as silver (core) and silicon or germanium (shell). For these particular realistic designs, the metamaterials present a negative index in the range of 1.2-1.55 ?m.

Paniagua-Domínguez, R.; López-Tejeira, F.; Marqués, R.; Sánchez-Gil, J. A.

2011-12-01

103

Optical waves in a gradient negative-index lens of a half-infinite length  

PubMed Central

Materials with negative permittivity and permeability can overcome the diffraction limit, thereby making the sub-wavelength imaging possible. In this study, we analyze the effects of gradient index on a half-infinite perfect lens. We assume that the sharp interface between the vacuum and the negative-index material is replaced by a smooth transition profile such that the index gradually changing from positive to negative. Interestingly, we find that if the graded index profile is modeled by a tanh function, we can have closed-form analytical solutions for this problem, which is a distinct advantage as numerical solutions are not accurate for evanescent waves with large transverse wave vectors. By analyzing the analytical formulas we confirm that a nonzero total absorption can occur even for a near-zero absorption coefficient in the steady-state limit and the image plane contains multiple sub-wavelength images of an object.

Ding, Yi S.; Chan, C. T.; Wang, R. P.

2013-01-01

104

Optical waves in a gradient negative-index lens of a half-infinite length.  

PubMed

Materials with negative permittivity and permeability can overcome the diffraction limit, thereby making the sub-wavelength imaging possible. In this study, we analyze the effects of gradient index on a half-infinite perfect lens. We assume that the sharp interface between the vacuum and the negative-index material is replaced by a smooth transition profile such that the index gradually changing from positive to negative. Interestingly, we find that if the graded index profile is modeled by a tanh function, we can have closed-form analytical solutions for this problem, which is a distinct advantage as numerical solutions are not accurate for evanescent waves with large transverse wave vectors. By analyzing the analytical formulas we confirm that a nonzero total absorption can occur even for a near-zero absorption coefficient in the steady-state limit and the image plane contains multiple sub-wavelength images of an object. PMID:24129667

Ding, Yi S; Chan, C T; Wang, R P

2013-10-16

105

Optical waves in a gradient negative-index lens of a half-infinite length  

NASA Astrophysics Data System (ADS)

Materials with negative permittivity and permeability can overcome the diffraction limit, thereby making the sub-wavelength imaging possible. In this study, we analyze the effects of gradient index on a half-infinite perfect lens. We assume that the sharp interface between the vacuum and the negative-index material is replaced by a smooth transition profile such that the index gradually changing from positive to negative. Interestingly, we find that if the graded index profile is modeled by a tanh function, we can have closed-form analytical solutions for this problem, which is a distinct advantage as numerical solutions are not accurate for evanescent waves with large transverse wave vectors. By analyzing the analytical formulas we confirm that a nonzero total absorption can occur even for a near-zero absorption coefficient in the steady-state limit and the image plane contains multiple sub-wavelength images of an object.

Ding, Yi S.; Chan, C. T.; Wang, R. P.

2013-10-01

106

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

107

Designer quantum materials  

NASA Astrophysics Data System (ADS)

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

Srinivasa, Vanita

108

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

Microsoft Academic Search

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

F. Bello

2011-01-01

109

Relationship between the Kramers-Kronig relations and negative index of refraction  

Microsoft Academic Search

The condition for a negative index of refraction with respect to the vacuum index is established in terms of permittivity and permeability susceptibilities. It is found that the imposition of analyticity to satisfy the Kramers-Kronig relations is a sufficiently general criterion for a physical negative index. The satisfaction of the Kramers-Kronig relations is a manifestation of the principle of causality

Alkim Akyurtlu; Adil-Gerai Kussow

2010-01-01

110

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

PubMed

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

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

2013-01-01

111

Multiresolution analysis for material design  

Microsoft Academic Search

The relationship between material microstructure and properties is the key to optimization and design of lightweight, strong, tough materials. Material properties are inherently a function of the microscale interactions at each distinct scale of deformation in a material. Currently, we rely on empirical data to define the structure–property link in the material design chain. A model is proposed here in

Cahal McVeigh; Franck Vernerey; L. Cate Brinson

2006-01-01

112

Negative beam displacements from negative-index photonic metamaterials.  

PubMed

It is well known that refraction of light at interfaces leads to a beam displacement for oblique incidence of light onto a slab of material. In ray optics and for homogeneous isotropic materials, the sign of this beam displacement is strictly identical to the sign of the refractive index. Our numerical calculations reveal negative beam displacements from state-of-the-art double-fishnet-type photonic metamaterials. This holds true for the "main" polarization corresponding to a negative phase velocity for normal incidence as well as for the "secondary" polarization with positive phase velocity. To understand and interpret these results, we also present exact analytical calculations for thin metal films showing that, in wave optics, the sign of the beam displacement (i.e., the sign of refraction) is generally not identical to the sign of the refractive index. PMID:19550696

Dolling, G; Klein, M W; Wegener, M; Schädle, Achim; Kettner, Benjamin; Burger, Sven; Linden, Stefan

2007-10-17

113

Three-Dimensional Approaches to Assembling Negative Index Metamedia.  

National Technical Information Service (NTIS)

This report describes progress accomplished in the past 5 years in the areas of (i) the design of plasmonic near-field plates for visible operation and corrugated near-field plates for point focusing; (ii) synthesis of gold nanoparticle patterns; (iii) pe...

R. D. Merlin

2012-01-01

114

Quantized-field description of light in negative-index media  

Microsoft Academic Search

Using a quantized-field approach, we show how radiative recoil, the Doppler effect, and spontaneous and stimulated radiation rates are affected when the radiator is embedded in a host medium having a negative index of refraction.

Peter W. Milonni; G. Jordan Maclay

2003-01-01

115

Design of a novel negative refractive index material based on numerical simulation  

NASA Astrophysics Data System (ADS)

This paper presents a novel metamaterial constructed with wires, spheres and hollow slabs (WSHS), which simultaneously exhibits negative permittivity and permeability. An electromagnetic wave simulation is performed based on the proposed metamaterial and shows that a negative refractive index is achieved for this metamaterial. Adjusting the lattice constant of the unit cell is an easy way to manipulate the frequency of negative index of this structure. A left-hand material prism is designed composed of metamaterial unit cells and the simulation on the proposed prism proves the left-hand behavior of the designed metamaterial.

Rizwan, Muhammad; Dou, Yan-Kun; Jin, Hai-Bo; Hou, Zhi-Ling; Kong, Ling-Bao; Li, Jing-Bo; Butt, Faheem K.; Rehman, Fida

2013-07-01

116

Energy, momentum, and force in classical electrodynamics: application to negative-index media  

NASA Astrophysics Data System (ADS)

The classical theory of electromagnetism is based on Maxwell's macroscopic equations, an energy postulate, a momentum postulate, and a generalized form of the Lorentz law of force. These seven postulates constitute the foundation of a complete and consistent theory, thus eliminating the need for physical models of polarization P and magnetization M - these being the distinguishing features of Maxwell's macroscopic equations. In the proposed formulation, P(r,t) and M(r,t) are arbitrary functions of space and time, their physical properties being embedded in the seven postulates of the theory. The postulates are self-consistent, comply with special relativity, and satisfy the laws of conservation of energy, linear momentum, and angular momentum. The Abraham momentum density pEM(r,t)=E(r, t)×H(r,t)/c2 emerges as the universal electromagnetic momentum that does not depend on whether the field is propagating or evanescent, and whether or not the host media are homogeneous, transparent, isotropic, linear, dispersive, magnetic, hysteretic, negative-index, etc. Any variation with time of the total electromagnetic momentum of a closed system results in a force exerted on the material media within the system in accordance with the generalized Lorentz law.

Mansuripur, Masud; Zakharian, Armis R.

2009-08-01

117

Energy, momentum, and force in classical electrodynamics: Application to negative-index media  

NASA Astrophysics Data System (ADS)

The classical theory of electromagnetism is based on Maxwell's macroscopic equations, an energy postulate, a momentum postulate, and a generalized form of the Lorentz law of force. These seven postulates constitute the foundation of a complete and consistent theory, thus eliminating the need for physical models of polarization P and magnetization M — these being the distinguishing features of Maxwell's macroscopic equations. In the proposed formulation, P(r, t) and M(r, t) are arbitrary functions of space and time, their physical properties being embedded in the seven postulates of the theory. The postulates are self-consistent, comply with special relativity, and satisfy the laws of conservation of energy, linear momentum, and angular momentum. The Abraham momentum density pEM(r,t) = E(r,t) × H(r,t) / c2 emerges as the universal electromagnetic momentum that does not depend on whether the field is propagating or evanescent, and whether or not the host media are homogeneous, transparent, isotropic, linear, dispersive, magnetic, hysteretic, negative-index, etc. Any variation with time of the total electromagnetic momentum of a closed system results in a force exerted on the material media within the system in accordance with the generalized Lorentz law.

Mansuripur, Masud; Zakharian, Armis R.

2010-12-01

118

Radar Absorbing Material Design.  

National Technical Information Service (NTIS)

Low observable platforms have extremely low radar cross section specifications that cannot be achieved by shaping alone. The application of radar absorbing material is necessary, in which case the appropriate constitutive parameters and thickness must be ...

C. K. Yuzcelik

2003-01-01

119

Advanced Materials by Design.  

National Technical Information Service (NTIS)

The study analyses 'the military and commercial opportunities presented by new structural materials technologies, and outlines the Federal policy objectives that are consistent with those opportunities'. The study also addresses 'the impact of advanced st...

1988-01-01

120

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

NASA Astrophysics Data System (ADS)

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 the operating wavelength, enabling one to identify the structure as an effective medium, with a negative index of refraction. This NRI metamaterial supports transverse electric (TE) waves, as opposed to related previous work on NRI-TL media that supported transverse magnetic (TM) waves. The dispersion characteristics are calculated using a simple, fast 2D loaded TL model with periodic (Bloch) boundary conditions. Subsequently the dispersion relation is simplified in the homogeneous limit, thus allowing one to identify effective permittivities and permeabilities, which are shown to be simultaneously negative. Simulations demonstrating the negative refraction of a plane wave on an interface between such a NRI uniplanar metamaterial and a commensurate positive-refractive-index (PRI) metamaterial verify the validity of the proposed concept and theory. A fully printed unit cell is presented at microwave frequencies (~10 GHz) along with a prescription for synthesizing an isotropic 3D transmission line NRI metamaterial based on this unit cell.

Elek, Francis; Eleftheriades, George V.

2005-08-01

121

Transmission line modelling method for planar boundaries containing positive and negative index media  

Microsoft Academic Search

In this paper, the analysis of the planar boundaries containing positive and negative index media by using transmission line modeling method is presented. This method is based on the similarity between the basic equations for uniform plane waves propagating through the boundaries and waves traveling across the connections of transmission lines. At the end of the analysis, it is observed

C. Sabah

2008-01-01

122

Negative index of refraction observed in a single layer of closed ring magnetic dipole resonators  

Microsoft Academic Search

We report the results of a spectroscopic study of a single layer of metallic single closed ring resonators on freestanding thin membrane at near normal and grazing angles of incidence. When the magnetic component of the light is perpendicular to the ring plane, we observe a negative index of refraction down to -1 around 150 THz, attributed to a strong

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

2007-01-01

123

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

Microsoft Academic Search

We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. Control of waveguide coupling yields a metamaterial consisting of a one-dimensional multilayer stack that exhibits

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

2010-01-01

124

Positive phase evolution of waves propagating along a photonic crystal with negative index of refraction  

Microsoft Academic Search

We analyze propagation of electromagnetic waves in a photonic crystal at frequencies at which it behaves as an effective medium with a negative index in terms of refraction at its interface with free space. We show that the phase evolution along the propagation direction is positive, despite the fact that the photonic crystal displays negative refraction following Snell's law, and

Alejandro Martínez; Javier Martí

2006-01-01

125

A negative index of refraction metamaterial based on a wire array embedded in ferrite  

Microsoft Academic Search

A metamaterial exhibiting a negative index of refraction can be fabricated from an array of conducting wires cladded with non-magnetic dielectric and embedded in a magnetic host medium. The wires are responsible for the ? < 0 property and the magnetic medium for the mu < 0 property. A near exact calculation of the electromagnetic response of this metamaterial indicated

G. Dewar

2005-01-01

126

Minimization of losses in a structure having a negative index of refraction  

Microsoft Academic Search

A structure consisting of an array of wires cladded with a nonmagnetic dielectric and embedded in a ferrimagnetic host has been calculated to have a negative index of refraction. The structure has moderate losses over a bandwidth of a few GHz. The calculation takes into account the skin effect within the wires and is valid provided the wavelength of electromagnetic

Graeme Dewar

2005-01-01

127

Wave Refraction in Negative-Index Media: Always Positive and Very Inhomogeneous  

Microsoft Academic Search

We present the first treatment of the refraction of physical electromagnetic waves in newly developed negative index media (NIM), also known as left-handed media (LHM). The NIM dispersion relation implies that group fronts refract positively even when phase fronts refract negatively. This difference results in rapidly dispersing, very inhomogeneous waves. In fact, causality and finite signal speed always prevent negative

P. M. Valanju; R. M. Walser; A. P. Valanju

2002-01-01

128

Calculations and Measurements of Wire\\/Split-Ring Negative Index Media  

Microsoft Academic Search

Broad band calculations (70 MHz - 20 GHz) and measurements (2 15 GHz) were performed on planar stacks of periodic arrays of double split rings interspersed with arrays of thin wires. Recent work on similar composite structures infers a negative index of refraction (n < 0) over a narrow frequency range. We have performed finite difference time domain (FDTD) calculations

Frederic Rachford; Douglas Smith; Peter Loschialpo; Donald Forester

2002-01-01

129

Comment on “Wave Refraction in Negative-Index Media: Always Positive and Very Inhomogeneous”  

Microsoft Academic Search

In a recent Physical Review Letter [1] Valanju Walser and Valanju (VWV)\\u000acalled into question the basis of work on the so called negative index media\\u000a(NIM). See for example [2,3]. The key point at issue is, `what is the group\\u000avelocity of a wave in NIM?'

JB Pendry; D. R. Smith

2003-01-01

130

Free space measured loss comparison of single and double Ring resonators for negative index media  

Microsoft Academic Search

Our work here investigates the combination of similar broadside coupled rings (BCRs) with negative permittivity posts in a metamaterial prism, rather than the previous guided-wave medium. Free space measurement of negative refraction through a prism has become our standard for proof of negative index.

John S. Derov; Beverly W. Turchinetz; James W. Dean; Everett E. Crisman; Alvin J. Drehman

2007-01-01

131

Characteristics of bound modes in coupled dielectric waveguides containing negative index media  

Microsoft Academic Search

We investigate the characteristics of guided wave modes in planar coupled waveguides. In particular, we calculate the dispersion relations for TM modes in which one or both of the guiding layers consists of negative index media (NIM)-where the permittivity and permeability are both negative. We find that the Poynting vector within the NIM waveguide axis can change sign and magnitude,

Klaus Halterman; J. Merle Elson; P. L. Overfelt

2003-01-01

132

Universal Description of Spherical Aberration Free Lenses Composed of Positive or Negative Index Media  

Microsoft Academic Search

We find that the function that describes the surface of spherical aberration free lenses can be used for both positive and negative refractive index media. With the inclusion of negative index, this function assumes the form of all the conic sections and expands the theory of aplanatic optical surfaces. There are two different symmetry centers with respect to the index

D. Schurig; D. R. Smith

2003-01-01

133

Unifying Approach to Left-Handed Material Design  

Microsoft Academic Search

In this letter we show that equivalent circuits offer a qualitative and even\\u000aquantitative simple explanation for the behavior of various types of\\u000aleft-handed (or negative index) meta-materials. This allows us to optimize\\u000adesign features and parameters, while avoiding trial and error simulations or\\u000afabrications. In particular we apply this unifying circuit approach in\\u000aaccounting for the features and in

Jiangfeng Zhou; Eleftherios N. Economon; Thomas Koschny; Costas M. Soukoulis

2006-01-01

134

Low loss broadband polarization independent fishnet negative index metamaterial at 40 GHz  

NASA Astrophysics Data System (ADS)

We present a polarization independent fishnet negative index metamaterial at 40 GHz. The structure is investigated theoretically using finite element method simulations and experimentally by measuring the amplitude and phase of the S-parameters. The experimental setup for free space measurements of both transmission and reflection is hereby introduced. The internal properties are thereafter retrieved and show the double-negative behavior of the structure. This negative index metamaterial exhibits very high transmission (-0.13 dB), low reflection (-33.1 dB) and a high figure of merit (FOM = |Re(n)/Im(n)| = 42), where the real part of the refractive index is nearly -1 (Re(n) = -0.93) at 40 GHz.

Zaoui, Wissem Sfar; Chen, Ke; Vogel, Wolfgang; Berroth, Manfred

2012-06-01

135

Negative index of refraction in metallic metamaterial comprising split-ring resonators  

Microsoft Academic Search

We numerically investigate the negative index of refraction in a metamaterial composed of metallic split-ring resonators, which exhibits simultaneously negative permittivity and permeability without resorting to additional metallic wires. It is confirmed that, in the left-handed band, negative permittivity is generated in analogy to the cut-wire metamaterial and negative permeability comes from the antisymmetric resonant mode, which occurs at a

Zheng-Gao Dong; Shuang-Ying Lei; Ming-Xiang Xu; Hui Liu; Tao Li; Fu-Ming Wang; Shi-Ning Zhu

2008-01-01

136

Double Negative Index of Refraction Observed in a Single Layer of Closed Ring Resonators  

Microsoft Academic Search

We report the results of a spectroscopic study of a single layer of nanoscale metallic single closed ring resonators on a free- standing thin membrane at near-normal and grazing angles of incidence^[1]. When the magnetic component of the light is perpendicular to the ring plane, we observe a so-called ``double'' negative index of refraction at near-infrared frequencies attributed to a

Zhao Hao; Michael Martin; Bruce Harteneck; Stefano Cabrini; Erik Anderson

2008-01-01

137

Propagation of a localized wavepacket in a metamaterial with a negative index of refraction  

Microsoft Academic Search

Propagation properties of electromagnetic waves in a medium with a negative index of refraction are investigated. A model\\u000a of a physical signal that combines simultaneously qualities of both a spatially-localized beam and a wavepacket was used as\\u000a the incident wave. Such a choice was necessary because of the strong frequency dispersion of metamaterials in the spectral\\u000a region with a negative

V. V. Grigor’ev; V. V. Kabanov

2008-01-01

138

Calculations and measurements of wire and\\/or split-ring negative index media  

Microsoft Academic Search

Broadband calculations (70 MHz-20 GHz) and measurements (2-15 GHz) were performed on planar stacks of two-dimensional double-split rings arrays interspersed with arrays of thin wires. Recent work on similar composite structures infers a negative index of refraction (n<0) over a narrow frequency range. We have performed finite-difference time-domain (FDTD) calculations on various combinations of ring geometries, wire arrays, and stack

F. J. Rachford; D. L. Smith; P. F. Loschialpo; D. W. Forester

2002-01-01

139

Characteristics of bound modes in coupled dielectric waveguides containing negative index media  

Microsoft Academic Search

We investigate the characteristics of guided wave modes in planar coupled\\u000awaveguides. In particular, we calculate the dispersion relations for TM modes\\u000ain which one or both of the guiding layers consists of negative index media\\u000a(NIM)-where the permittivity and permeability are both negative. We find that\\u000athe Poynting vector within the NIM waveguide axis can change sign and\\u000amagnitude,

Klaus Halterman; J. Merle Elson; P. L. Overfelt

2003-01-01

140

Experimental verification of negative refraction for a wedge-type negative index metamaterial operating at terahertz  

NASA Astrophysics Data System (ADS)

We report on angle-resolved time domain spectroscopy (TDS) carried out on a prismlike negative index metamaterial operating around 0.5 THz. The wedge-type devices are constituted of hole arrays etched in gold thin films, which are stacked according to a sequential mask shift. By means of a goniometric TDS setup and subsequent analysis of the temporal waveforms, negative refraction is demonstrated with values close to n=-1 around 0.5 THz. The dispersion of refractive index retrieved from the Snell-Descartes law shows comparable trends in comparison with the dispersion deduced from complex transmission and reflection measurements on slab-type samples.

Wang, Shengxiang; Garet, Frédéric; Blary, Karine; Lheurette, Eric; Coutaz, Jean Louis; Lippens, Didier

2010-11-01

141

Numerical simulations of negative-index refraction in wedge-shaped metamaterials.  

PubMed

A wedge-shaped structure made of split-ring resonators (SRR) and wires is numerically simulated to evaluate its refraction behavior. Four frequency bands, namely, the stop band, left-handed band, ultralow-index band, and positive-index band, are distinguished according to the refracted field distributions. Negative phase velocity inside the wedge is demonstrated in the left-handed band and the Snell's Law is conformed in terms of its refraction behaviors in different frequency bands. Our results confirmed that negative index of refraction indeed exists in such a composite metamaterial and also provided a convincing support to the results of previous Snell's Law experiments. PMID:16090107

Dong, Z G; Zhu, S N; Liu, H; Zhu, J; Cao, W

2005-07-12

142

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

SciTech Connect

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

Wang, Y.; Wang, X.; Rybczynski, J.; Wang, D.Z.; Kempa, K.; Ren, Z.F. [Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467 (United States)

2005-04-11

143

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

144

Negative index of refraction in metallic metamaterial comprising split-ring resonators.  

PubMed

We numerically investigate the negative index of refraction in a metamaterial composed of metallic split-ring resonators, which exhibits simultaneously negative permittivity and permeability without resorting to additional metallic wires. It is confirmed that, in the left-handed band, negative permittivity is generated in analogy to the cut-wire metamaterial and negative permeability comes from the antisymmetric resonant mode, which occurs at a frequency band about 3 times higher than the fundamental magnetic resonance proposed by Pendry [IEEE Trans. Microwave Theory Tech. 47, 2075 (1999)]. PMID:18643188

Dong, Zheng-Gao; Lei, Shuang-Ying; Xu, Ming-Xiang; Liu, Hui; Li, Tao; Wang, Fu-Ming; Zhu, Shi-Ning

2008-05-29

145

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

146

Reversal of the dipole vortex in a negative index of refraction material  

Microsoft Academic Search

When a small particle is illuminated by a circularly polarized laser beam, the induced electric dipole moment rotates in a plane. The flow lines of the emitted electromagnetic energy are the field lines of the Poynting vector. When the particle is embedded in a dielectric, these field lines have a vortex structure, and the rotation in the vortex has the

Xin Li; Henk F. Arnoldus

2010-01-01

147

Application of the transfer matrix method to reflection gratings in positive and negative index materials  

NASA Astrophysics Data System (ADS)

The transfer matrix method (TMM) has been used to analyze plane wave and beam propagation through linear photonic bandgap structures. Here, we apply TMM to determine the exact spatial behavior of TE and TM waves in periodic refractive index structures of arbitrary thickness. First, we extend the TMM approach to analyze plane wave propagation through Kerr type nonlinear media. Secondly, we analyze second harmonic fields in a 1D nonlinear photonic crystal for arbitrary angle of incidence of the fundamental plane wave. This allows us to construct the overall transfer matrix of nonlinear waves for the whole nonlinear optical structure from all the individual layer transfer matrices. We extend this method to analyze the effect of second order nonlinearity to beam propagation by applying TMM to the angular spectral components of the beam(s).

Aylo, R.; Li, H.; Nehmetallah, G.; Banerjee, P. P.

2012-10-01

148

Interplay between mode conversion and surface wave excitation phenomena in a transition layer between positive and negative index media  

Microsoft Academic Search

We investigate theoretically the interplay between the resonant absorption due to mode conversion and the excitation of extremely strong surface waves in a transition layer between positive and negative index media.

Dae Jung Yu; Kihong Kim; Dong-Hun Lee; Hanjo Lim

2009-01-01

149

Materials selection in mechanical design  

Microsoft Academic Search

A novel materials-selection procedure has been developed and implemented in software. The procedure makes use of Materials Selection Charts: a new way of displaying material property data; and performance indices: combinations of material properties which govern performance. Optimisation methods are employed for simultaneous selection of both material and shape.

M. F. ASHBY; D. CEBON

1993-01-01

150

Thrust Chamber Materials and Design Concepts Evaluation.  

National Technical Information Service (NTIS)

A program was conducted to investigate and evaluate new and unique designs of non-regenerative combustion chambers and nozzles using new materials or new techniques for applying the best materials. Analysis of information obtained through literature searc...

D. N. Crump E. G. Parks E. N. Poulos J. B. Pearson K. J. Smith

1967-01-01

151

Brittle Materials Design, High Temperature Gas Turbine.  

National Technical Information Service (NTIS)

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, will utilize a small vehicular gas turbine w...

A. F. McLean R. R. Baker R. J. Bratton D. G. Miller

1976-01-01

152

Some Thoughts on DIY Materials Design.  

ERIC Educational Resources Information Center

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

Block, David

1991-01-01

153

Brittle Materials Design, High Temperature Gas Turbine.  

National Technical Information Service (NTIS)

The 'Brittle Materials Design, High temperature Gas Turbine' program objective is to demonstrate successful use of brittle materials in demanding high temperature structural applications. A small vehicular gas turbine engine and a static test rig, each us...

A. F. McLean E. A. Fisher R. J. Bratton D. G. Miller

1975-01-01

154

Brittle Materials Design, High Temperature Gas Turbine.  

National Technical Information Service (NTIS)

The Brittle Materials Design, High Temperature Gas Turbine program is to demonstrate successful use of brittle materials in demanding high temperature structural applications. A small vehicular gas turbine and a large stationary gas turbine, each utilizin...

A. F. McLean E. A. Fisher R. J. Bratton

1974-01-01

155

Toward designing new sensoaesthetic materials  

Microsoft Academic Search

In ancient societies, there was no arts\\/science split. The development of materials was driven both by aesthetic and technological goals. At the end of the 19th century, things changed dramatically. Scientists started being able to analyze composition, detect structure, and make a link between structure and properties. The subsequent 20th-century revolution in new materials changed almost all aspects of human

Mark A. Miodownik

2007-01-01

156

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

Microsoft Academic Search

Metamaterials are engineered ring and wire composites whose response to an incident electromagnetic wave can be described\\u000a by an effective negative dielectric permittivity ? and magnetic permeability ?. Simultaneous negative ? and ? within a given frequency band of a metamaterial gives rise to a negative index of refraction n. This has been demonstrated via a Snell’s law experiment. The

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

157

Effects of numerical dispersion on the accuracy of FDTD modeling of propagating and evanescent waves in negative index media  

Microsoft Academic Search

Discrete space-time methods, primarily FDTD, have played a major role in illuminating the underlying physics of unconventional phenomena (negative refraction, growing evanescent waves and super-lensing) in negative index media. Yet, a survey of the relevant FDTD literature indicates a number of contradictory results, which stem from inherent limitations of the method. This paper is focused on the impact of numerical

Costas D. Sarris; Edward S. Rogers Sr

2009-01-01

158

OLED microdisplay design and materials  

Microsoft Academic Search

AMOLED microdisplays from eMagin Corporation are finding growing acceptance within the military display market as a result of their excellent power efficiency, wide operating temperature range, small size and weight, good system flexibility, and ease of use. The latest designs have also demonstrated improved optical performance including better uniformity, contrast, MTF, and color gamut. eMagin's largest format display is currently

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

2010-01-01

159

OLED microdisplay design and materials  

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

160

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

161

MATERIAL DESIGN IN PHYSICAL MODELING SOUND SYNTHESIS  

Microsoft Academic Search

This paper deals with designing material parameters for physical models. It is shown that the characteristic relation between modal frequencies and damping factors of a sound object is the acoustic invariant of the material from which the body is made. Thus, such characteristic relation can be used for designing damping models for a conservative physical model to represent a particular

Pirouz Djoharian

1999-01-01

162

Field data reflect improved bit material, design  

SciTech Connect

This article reports on the gains made in polycrystalline diamond compact (PDC) bit improvement as a result of materials and design technology advances in the past five years. It compares actual field performance of the new designs with older bits. Without the advances in materials technology, many of the bit designs now available would not be possible and the full benefits of oil-based mud would not be realized.

Dennis, M.; Kelety, J.T.; Clark, D.A.

1987-09-14

163

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

164

Microstructural design in cellular materials. Progress report.  

National Technical Information Service (NTIS)

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 w...

L. J. Gibson

1992-01-01

165

Optimal Design of Structures Incorporating 'Smart Materials'.  

National Technical Information Service (NTIS)

The purpose of this project was to develop a rigorous theoretical foundation of the design of structures incorporating general 'smart' materials, and to explore, extend and develop the use of sensors and actuators that employ 'finite length' paths. It is ...

P. D. Washabaugh J. E. Taylor A. M. Waas

1998-01-01

166

Multifunctional design of prismatic cellular materials  

Microsoft Academic Search

Low density, prismatic cellular materials have a combination of properties that make them suitable for multifunctional or multi-physics applications such as ultralight load-bearing combined with energy absorption and heat transfer. In this work, non-uniform, graded cellular materials are designed to achieve superior thermal and structural performance. A general multifunctional design approach is presented that integrates multiobjective decision-making with multi-physics analysis

Carolyn C. Seepersad; Rajesh S. Kumar; Janet K. Allen; Farrokh Mistree; David L. Mcdowell

2004-01-01

167

Materials and design interaction in advanced reactors  

Microsoft Academic Search

In the development of advanced gas-cooled, light-water-cooled, or heavy-water-cooled reactors, there are many challenges facing the materials engineer and the designer. High-temperature gas-cooled reactors offer considerable potential as efficient generators of electricity and producers of high quality process heat. Design innovations and further alloy development will be needed to overcome the many materials problems created by their high temperature of

Boulton

1978-01-01

168

Mimicry of natural material designs and processes  

SciTech Connect

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. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States); Richman, R.H. [Daedalus Associates, Inc., Mountain View, CA (United States); McNaughton, W.P. [Cornice Engineering, Durango, CO (United States)

1995-06-01

169

Thermophotovoltaic emitter material selection and design  

SciTech Connect

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

Saxton, P.C.; Moran, A.L.; Harper, M.J.; Lindler, K.W. [Naval Academy, Annapolis, MD (United States)

1997-07-01

170

Simulation-assisted materials design for the concurrent design of materials and products  

NASA Astrophysics Data System (ADS)

Engineering design has historically been taught using the paradigm of selecting materials on the basis of tabulated databases of properties (mechanical, physical, chemical, etc.). Recent trends have moved toward concurrent design of material composition and microstructure together with the component/system level. The goal is to tailor materials to meet specifi ed ranges of performance requirements of the overall system. Often these multiple performance requirements are in confl ict in terms of their demands on composition and microstructure. This paper explores the elements of a decision-based robust design framework for concurrent design of materials and products, focusing on enhancing the fraction of decisions supported by modeling and simulation.

McDowell, David L.

2007-09-01

171

Extending ITER materials design to welded joints  

NASA Astrophysics Data System (ADS)

This paper extends the ITER materials properties documentation to weld metals and incorporates the needs of Test Blanket Modules for higher temperature materials properties. Since the main structural material selected for ITER is type 316L(N)-IG, the paper is focused on weld metals and joining techniques for this steel. Materials properties data are analysed according to the French design and construction rules for nuclear components (RCC-MR) and design allowables are equally derived using the same rules. Particular attention is paid to the type of weld metal, to the type and position of welding and their influence on the materials properties data and design allowables. The primary goal of this work, starting with 19-12-2 weld metal, is to produce comprehensive materials properties documentations that when combined with codification and inspection documents would satisfy ITER licensing needs. As a result, structural stability and capability of welded joints during manufacturing of ITER components and their subsequent service, including the effects of irradiation and eventual incidental or accidental situations, are also covered.

Tavassoli, A.-A. F.

2007-08-01

172

Designer materials for a secure future  

NASA Astrophysics Data System (ADS)

Materials for armor applications are increasingly being required to be strong and light-weight as a consequence of increasing threat levels. We focus on materials response subjected to impact loads, understanding deformation and failure mechanisms, and developing validated mechanism-based models capable of predicting materials response under high rate loading conditions. As a specific example, we will examine the dynamic behavior of nanocrystalline aluminum using atomistic simulations. The dynamic behavior of this material is discussed in terms of competing deformation mechanisms--slip and twinning. Insights from high strain rate atomistic simulations were used in developing a fundamental mechanism-based analytical model to assist in the microstructural design of advanced materials to tailor their macroscopic properties.

Daphalapurkar, Nitin P.; Ramesh, K. T.

2012-05-01

173

Quantum Monte Carlo for Materials Design  

NASA Astrophysics Data System (ADS)

When designing new materials it is important to have an accurate measure of the material's formation energy to assess thermodynamic stability and chemical activity. Computational materials science holds the potential to accurately predict formation energies, but widely-used methods such as density functional theory often yield large errors when calculating energy differences between compounds with significantly different electronic structures. More accurate quantum chemical methods tend to scale poorly with system size, making it infeasible to apply them to many materials. One exception is quantum Monte Carlo (QMC), which effectively scales linearly or better with system size when calculating formation energy per atom. QMC scales perfectly with the number of processors, making it ideally positioned to take advantage of the rapidly growing core count in central and graphics processing units. It has been shown that quantum Monte Carlo can successfully predict formation energies for some solid state materials, but a broad assessment has been lacking. We have run QMC calculations on a variety of different materials for which high-quality experimental data exists. We present data on the cost and accuracy of QMC, providing insight into the role QMC will play in materials design.

Mueller, Tim; Wagner, Lucas; Grossman, Jeffrey

2011-03-01

174

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

SciTech Connect

The present investigation is concerned with the study of pulsed second-harmonic generation under conditions of phase and group velocity mismatch, and generally low conversion efficiencies and pump intensities. In positive-index, nonmetallic materials, we generally find qualitative agreement with previous reports regarding the presence of a double-peaked second harmonic signal, which comprises a pulse that walks off and propagates at the nominal group velocity one expects at the second-harmonic frequency, and a second pulse that is 'captured' and propagates under the pump pulse. We find that the origin of the double-peaked structure resides in a phase-locking mechanism that characterizes not only second-harmonic generation, but also {chi}{sup (3)} processes and third-harmonic generation. The phase-locking mechanism that we describe occurs for arbitrarily small pump intensities, and so it is not a soliton effect, which usually relies on a threshold mechanism, although multicolor solitons display similar phase locking characteristics. Thus, in second harmonic generation a phase-matched component is always generated, even under conditions of material phase mismatch: This component is anomalous, because the material does not allow energy exchange between the pump and the second-harmonic beam. On the other hand, if the material is phase matched, phase locking and phase matching are indistinguishable, and the conversion process becomes efficient. We also report a similar phase-locking phenomenon in negative index materials. A spectral analysis of the pump and the generated signals reveals that the phase-locking phenomenon causes the forward moving, phase-locked second-harmonic pulse to experience the same negative index as the pump pulse, even though the index of refraction at the second-harmonic frequency is positive. Our analysis further shows that the reflected second-harmonic pulse generated at the interface and the forward-moving, phase-locked pulse appear to be part of the same pulse initially generated at the surface, part of which is immediately back-reflected, while the rest becomes trapped and dragged along by the pump pulse. These pulses thus constitute twin pulses generated at the interface, having the same negative wave vector, but propagating in opposite directions. Almost any break of the longitudinal symmetry, even an exceedingly small {chi}{sup (2)} discontinuity, releases the trapped pulse which then propagates in the backward direction. These dynamics are indicative of very rich and intricate interactions that characterize ultrashort pulse propagation phenomena.

Roppo, Vito; Centini, Marco; Sibilia, Concita; Bertolotti, Mario; De Ceglia, Domenico; Scalora, Michael; Akozbek, Neset; Bloemer, Mark J.; Haus, Joseph W.; Kosareva, Olga G.; Kandidov, Valery P. [Dipartimento di Energetica, University of Rome La Sapienza, Via Scarpa 16, Rome (Italy); Charles M. Bowden Research Facility, RDECOM, US Army Aviation and Missile Command, Redstone Arsenal, AL 35803 (United States); Electro-Optics Program, University of Dayton, Dayton, Ohio 45469-0245 (United States); International Laser Center, Physics Department, Moscow State University, Moscow 119992 (Russian Federation)

2007-09-15

175

Carbon nanotube materials characterization and devices design  

NASA Astrophysics Data System (ADS)

The objective of this research is to characterize the electrical and mechanical properties of Carbon Nanotube (CNT) materials, and explore possible device applications for these materials. In order to achieve this goal, different forms of Carbon Nanotube materials---including Carbon Nanotubes, Carbon Nanotube Arrays, Carbon Nanotube Ribbon, Carbon Nanotube Thread, and sub-micrometer Carbon Nanotube Thread---were tested under a Scanning Electron Microscope (SEM) using a Micromanipulator (MM). Video and sound recording of the testing in the microscope provided new understanding how thread is formed and how nanotube materials fail. As-produced and thermally treated nanotubes were also tested. The main electrical parameters measured were electrical resistivity and maximum current density. The main mechanical property measured was strength. Together, these parameters are helping to determine the strongest and most conductive forms of CNT material. Putting nanotube materials into application is the ultimate goal of this continuing research. Several aggressive application ideas were investigated in a preliminary way in this work. In biomedical applications, a bundle of CNTs was formed for use as an electrode for accurate biosensing. A simple robot was designed using CNT electrical fiber. The robot was powered by two solenoids and could act as an in-body sensor and actuator to perform some impossible tasks from the viewpoint of current medical technology. In aerospace engineering, CNT materials could replace copper wire to reduce the weight of aircraft. Based on the excellent mechanical properties of CNT materials, a challenging idea is to use CNT material to build elevators to move payloads to outer space without using rockets. This dissertation makes contributions in the characterization of nanotube materials and in the design of miniature electromagnetic devices.

Li, Weifeng

176

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

Microsoft Academic Search

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

Keith Penney

2009-01-01

177

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

Code of Federal Regulations, 2013 CFR

...statistical basis. (b) Material design values must be chosen to...shown by selecting material design values which assure material...environmental conditions, such as temperature and moisture, on material design values used in an...

2013-01-01

178

Negative index metamaterial for selective angular separation of microwaves by polarization  

Microsoft Academic Search

Materials with simultaneously negative electric permittivity and magnetic permeability are referred to as left handed, and are also called backward wave and double negative media. The first experimental demonstration of such a metamaterial combined metallic split ring resonators with posts etched on opposite sides of dielectric boards. The boards are usually stacked in parallel planes with insulating spacers to form

J. S. Derov; B. Turchinetz; E. E. Crisman; A. J. Drehman; R. Wing

2004-01-01

179

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

180

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Material, design and construction. 58...SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY...58.05-1 Material, design and construction. (a) The material, design, construction,...

2011-10-01

181

Bistable and self-tunable negative-index metamaterial at optical frequencies.  

PubMed

We introduce a metamaterial design composed of square plasmonic loops loaded by Kerr nonlinearities that combines enhanced nonlinear response with strong artificial magnetism, ensuring a negative refractive index with bistable and self-tunable response. We verify with full-wave simulations that positive-to-negative switching of refractive index may be obtained with moderate loss. The design of a finite-size metamaterial prism is also presented, supporting at the same frequency, and for the same light intensity, positive or inverted Snell refraction as a function of its previous excitation history. PMID:21469804

Chen, Pai-Yen; Farhat, Mohamed; Alù, Andrea

2011-03-08

182

Negative index of refraction microwave frequency structures based on high permittivity inclusions and effective medium theory  

Microsoft Academic Search

A metamaterial designed to have simultaneous negative permittivity and permeability may be built from a cubic lattice of spheres and a three dimensional wire grid embedded in a host medium. Based on reported theory, the spheres must have higher permittivity than the surrounding medium and be smaller than the wavelength of the electromagnetic radiation in the host medium. Metamaterials based

James M. L. Cramer; Andrew J. Gatesman; Robert H. Giles; William E. Nixon

2008-01-01

183

Group theoretical description of artificial magnetic metamaterials utilized for negative index of refraction  

Microsoft Academic Search

Group theoretical methods are used to determine the electromagnetic\\u000aproperties of artificial magnetic meta-materials, based solely upon the\\u000asymmetries of the underlying constituent particles. Point groups for such\\u000amaterials are determined. From the transformation properties of an\\u000aelectromagnetic (EM) basis under symmetries of the particles, it is possible to\\u000adetermine, (i) the EM modes of the particles, (ii) the form

W. J. Padilla

2005-01-01

184

Materials Design of Advanced Performance Metal Catalysts  

SciTech Connect

The contribution of materials design to the fabrication of advanced metal catalysts is highlighted, with particular emphasis on the construction of relatively complex contact structures surrounding metal nanoparticles. Novel advanced metal catalysts can be synthesized via encapsulation of metal nanoparticles into oxide shells, immobilization of metal oxide core-shell structures on solid supports, post-modification of supported metal nanoparticles by surface coating, and premodification of supports before loading metal nanoparticles. Examples on how these materials structures lead to enhanced catalytic performance are illustrated, and a few future prospects are presented.

Ma, Zhen [ORNL; Dai, Sheng [ORNL

2008-01-01

185

Real space observation of two-dimensional Bloch wave interferences in a negative index photonic crystal cavity  

NASA Astrophysics Data System (ADS)

We report here the direct observation of two-dimensional (2D) Bloch wave interferences in a negative index photonic crystal by using optical near-field microscopy techniques. The photonic crystal is formed by a defectless honeycomb lattice of air holes etched in III-V semiconductor slab. A scanning near-field optical microscope is used to visualize spatially, as well as spectrally, the light distribution inside the photonic crystal. The recorded near-field spectra and maps presented here unambiguously demonstrate the Bloch wave interferences within the photonic crystal. Then, the spectral and spatial evolution of these interferences allows us to recover experimentally the 2D band diagram of the photonic crystal demonstrating that this structure operates in a negative refraction regime and acts as a left-handed cavity.

Lalouat, Loïc; Cluzel, Benoit; Salomon, Laurent; Dumas, Colette; Seassal, Christian; Louvion, Nicolas; Callard, Ségolène; de Fornel, Frédérique

2008-12-01

186

Computational design of microvascular biomimetic materials  

NASA Astrophysics Data System (ADS)

Biomimetic microvascular materials are increasingly considered for a variety of autonomic healing, cooling and sensing applications. The microvascular material of interest in this work consists of a network of hollow microchannels, with diameters as small as 10 mum, embedded in a polymeric matrix. Recent advances in the manufacturing of this new class of materials have allowed for the creation of very complex 2D and 3D structures. The computational design of such network structures, which is the focus of this work, involves a set of particular challenges, including a large number of design variables (e.g., topology of the network, number of diameters to consider and their sizes) that define the network, and a large number of multidisciplinary objective functions and constraints that drive the optimization process. The computational design tool to be developed must be capable of capturing the trade-off between the different objective and constraint functions, as, for example, networks designed for flow efficiency are likely to have a topology that is very different from those designed for structural integrity or thermal control. In this work, we propose to design these materials using Genetic Algorithms (GAs), the most common methodology within a broader category of Evolutionary Algorithms (EAs). GAs can be combined with a Pareto-selection mechanism to create Multi-Objective Genetic Algorithms (MOGAs), which enable the optimization of an arbitrary number of objective functions. As a result, a Pareto-optimal front is obtained, where all candidates are optimal solutions to the optimization problem. Adding a procedure to deal with constraints results in a powerful tool for multi-objective constrained optimization. The method allows the use of discrete variable problems and it does not require any a priori knowledge of the optimal solution. Furthermore, GAs search the entire decision space so the optimal solutions found are likely to be global. TheMOGAoptimization framework is also combined with a physical solver based on advanced finite element methods to study the thermal behavior of these materials. Because the MOGA requires a vast number of individual evaluations, emphasis is placed on the computational efficiency of the solver. Thus, a simplified formulation is used to take into account the cooling effect of the fluid, instead of solving the conjugate heat transfer problem for obtaining the temperature field in both solid and fluid domains. The Generalized Finite Element Method (GFEM) is adopted because accurate finite element approximations of the temperature field can be obtained on finite element meshes that are independent of the geometry of the embedded network. Numerical experiments of multi-physics optimization involving flow efficiency, void volume fraction and thermal control are presented. Results show that the tradeoffs between conflicting objectives is well captured so that the optimal design is readily available to the analyst.

Aragon, Alejandro Marcos

187

First principles materials design for semiconductor spintronics  

Microsoft Academic Search

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

K. Sato; H. Katayama-Yoshida

2002-01-01

188

Designing Educative Curriculum Materials to Promote Teacher Learning  

Microsoft Academic Search

Curriculum materials for Grades K–12 that are intended to promote teacher learning in addition to student learning have come to be called educative curriculum materials. How can K–12 curriculum materials be designed to best promote teacher learning? What might teacher learning with educative curriculum materials look like? The authors present a set of design heuristics for educative curriculum materials to

Elizabeth A. Davis; Joseph S. Krajcik

2005-01-01

189

First principles materials design for semiconductor spintronics  

NASA Astrophysics Data System (ADS)

Materials design of new functional diluted magnetic semiconductors (DMSs) is presented based on first principles calculations. The stability of the ferromagnetic state in ZnO-, ZnS-, ZnSe-, ZnTe-, GaAs- and GaN-based DMSs is investigated systematically and it is suggested that V- or Cr-doped ZnO, ZnS, ZnSe and ZnTe are candidates for high-TC ferromagnetic DMSs. V-, Cr- or Mn-doped GaAs and GaN are also candidates for high-TC ferromagnets. It is also shown that Fe-, Co- or Ni-doped ZnO is ferromagnetic. In particular, the carrier-induced ferromagnetism in ZnO-based DMSs is investigated and it is found that their magnetic states are controllable by changing the carrier density. The origin of the ferromagnetism in the DMSs is also discussed.

Sato, K.; Katayama-Yoshida, H.

2002-04-01

190

Robust Design of Cellular Materials With Topological and Dimensional Imperfections  

Microsoft Academic Search

A paradigm shift is underway in which the classical materials selection approach in engineering design is being replaced by the design of material structure and processing paths on a hierarchy of length scales for multifunctional performance requirements. In this paper, the focus is on designing mesoscopic material topology—the spatial arrangement of solid phases and voids on length scales larger than

Carolyn Conner Seepersad; Janet K. Allen; David L. McDowell; Farrokh Mistree

2006-01-01

191

Bi-objective optimization design of functionally gradient materials  

Microsoft Academic Search

In this paper, a procedure for bi-objective optimization design of functionally gradient materials (FGM) is presented. Different microstructures formed by two primary materials are evaluated by a micromechanical analysis method. Macroscopically, FGMs are optimally designed by using these microstructures. Instead of using conventional simply assumed power law material distribution functions, a generic material distribution function is used. The bi-objective FGM

Jinhua Huang; George M. Fadel; Vincent Y. Blouin; Mica Grujicic

2002-01-01

192

A framework for material handling system design justification  

Microsoft Academic Search

The integrating nature of material handling systems renders their design and economic justification critical to the performance of a manufacturing system. This paper describes a framework for the concurrent design and economic justification of a material handling system (MHS). An approach to concurrent design and economic justification termed design justification is presented, followed by a discussion of the nature of

J. S. NOBLE; J. M. A. TANCHOCO

1993-01-01

193

Generation of highly directional beam by k-space filtering using a metamaterial flat slab with a small negative index of refraction  

Microsoft Academic Search

The authors show how a flat slab made of a metamaterial engineered to have a small negative index of refraction can be used to reshape radiation emitted from an isotropic source and produce a highly directional output beam. The slab makes a filtering of high transverse wave vectors of the input diverging beam. The predicted phenomenon is demonstrated at microwave

Alejandro Martínez; Miguel A. Piqueras; Javier Martí

2006-01-01

194

Material Design of High Performance Glasses Discussed.  

National Technical Information Service (NTIS)

High-grade materials are necessary for building a highly advanced system. This is the reason new and up-to-date materials attract attention. In the field of glass, a material called the new glass is attracting attention as an up-to-date glass. In view of ...

1987-01-01

195

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

196

Space & Materials: A Second Year Design Curriculum.  

ERIC Educational Resources Information Center

|Design students provide a constant source of energy that moves into the mainstream of society. Their energy needs to be directed toward improving the characteristics of the built environment at every physical and economic scale of activity. Teaching design involves a broad range of decisions on how to present relevant design education content to…

Ziff, Matthew

197

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

198

Printed circuit board material and design considerations for wireless applications  

Microsoft Academic Search

Designers are moving towards material systems which can be fabricated using conventional epoxy\\/glass printed circuit board (PCB) processes. This allows microwave circuits to be built using the vast fabrication infrastructure available for digital circuits. This paper provides basic background information about substrate material characteristics and design considerations, which are critical for wireless applications. Material characteristics discussed include dissipation factor, dielectric

Bob Daigle

1996-01-01

199

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

200

Material, process, and product design of thermoplastic composite materials  

Microsoft Academic Search

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

Heming Dai

2001-01-01

201

Synthesis and design of silicide intermetallic materials  

SciTech Connect

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

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

1998-11-01

202

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

203

New Generation Photonics Materials: Design, Development, Characterization and Applications.  

National Technical Information Service (NTIS)

A significant amount of research was accomplished in the design, development, characterization and applications of two types of photonic materials: Multiphoton absorbing materials and hybrid nanocomposites for photorefractivity. We synthesized a new class...

P. N. Prasad

2004-01-01

204

Brittle Materials Design, High Temperature Gas Turbine.  

National Technical Information Service (NTIS)

The program objective is to demonstrate successful use of brittle materials in high temperature structural applications. A small vehicular gas turbine and a large stationary gas turbine, each using uncooled ceramic components, will be utilized in this pro...

A. F. McLean E. A. Fisher R. J. Bratton D. G. Miller

1975-01-01

205

Design for containment of hazardous materials  

SciTech Connect

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

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

1991-03-01

206

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

207

Design optimization method for compliant mechanisms and material microstructure  

Microsoft Academic Search

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

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

1998-01-01

208

Towards the Molecular Design of Composite Materials.  

National Technical Information Service (NTIS)

The objective of this project is to develop a theory of the statistical thermodynamics at polymer blends and block copolymer systems in which the theory relates microscopic and macroscopic properties and thereby assists in the molecular design of composit...

K. F. Freed

1994-01-01

209

The design of exotic superhard materials  

Microsoft Academic Search

Diamond has the highest bond energy per unit volume of all known materials, and hence it is assumed to possess the highest hardness. Diamond’s hardness comes from its small atoms that each of them forms four covalent bonds. To make a structure harder than diamond, its atoms must be smaller than carbon, and\\/or these atoms form at least four covalent

James Sung

2001-01-01

210

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

211

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

212

Synthesis and Design of Silicide Intermetallic Materials  

SciTech Connect

The overall objective of this program is to develop structural silicide-based materials with optimum combinations of elevated temperature strength/creep resistance, low temperature fracture toughness, and high temperature oxidation and corrosion resistance for applications of importance to the US processing industry. A further objective is to develop silicide-based prototype industrial components. The ultimate aim of the program is to work with industry to transfer the structural silicide materials technology to the private sector in order to promote international competitiveness in the area of advanced high temperature materials and important applications in major energy-intensive US processing industries. The program presently has a number of industrial connections, including a CRADA with Johns Manville Corporation targeted at the area of MoSi{sub 2}-based high temperature materials for fiberglass melting and processing applications. The authors are also developing an interaction with the Institute of Gas Technology (IGT) to develop silicides for high temperature radiant gas burner applications, for the glass and other industries. With the Exotherm Corporation, they are developing advanced silicide powders for the fabrication of silicide materials with tailored and improved properties for industrial applications. In October 1998, the authors initiated a new activity funded by DOE/OIT on ``Molybdenum Disilicide Composites for Glass Processing Sensors''. With Accutru International Corporation, they are developing silicide-based protective sheaths for self-verifying temperature sensors which may be used in glass furnaces and other industrial applications. With Combustion Technology Inc., they are developing silicide-based periscope sight tubes for the direct observation of glass melts.

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

1999-05-14

213

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

214

Bio-inspired design of intelligent materials  

NASA Astrophysics Data System (ADS)

Several examples of sensors and actuators inherent in biological species are reviewed with emphasis on their mechanisms for a given set of stimuli. Examples include, action plants (Venus flytrap, Cucumber tendrils) and bamboo, and algae. Based on these examples and their mechanisms, we designed artificial actuators, FGM piezo actuators and electroactive polymer actuators.

Taya, Minoru

2003-07-01

215

Evaluating Course Design Principles for Multimedia Learning Materials  

ERIC Educational Resources Information Center

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

Scott, Bernard; Cong, Chunyu

2010-01-01

216

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

217

Decision support system for material handling and packaging design  

Microsoft Academic Search

The reliability of the materials handling process involving automated stacking of packages on a pallet or automated sorting of packages in a distribution system depends mainly on the design of the package and the material used for the package. Many problems can be eliminated that result in a higher utilization of the system if the package is designed not only

Mats I. Johnsson; Abdel K. Mazouz; Chingping Han

1992-01-01

218

Scientific Design of Digital Materials for Technology Enhanced Learning1  

Microsoft Academic Search

In this paper, based on recent scientific findings in the fields of neurology, evolutionary psychology and cognitive psychology that throw a very strong insight about how digital materials for training and education should be designed, we propose a series of guidelines for digital materials design and development.

Raul V. Ramirez-Velarde

219

Design of a smart material actuator for rotor control  

NASA Astrophysics Data System (ADS)

The results of a study to conceptually define an on-blade smart material actuator for primary and active control on a servoflap rotor are presented. Actuator design drivers, goals, and requirements are defined. For a previously developed hybrid actuator concept, the design of the cyclic and active (high speed) control actuator and feasibility of the collective (low speed) actuator and stroke multiplier are investigated. Sizing of actuator components based on AH-64 servoflap requirements shows that collective control using shape memory alloys is well within the capability of the material. Cyclic and active control using magnetostrictive material, leads to a reduced maneuver envelope due to weight and volume constraints. The promise of smart materials can be realized incrementally as the materials and actuator design approaches mature. Future improvements in smart material performance and actuator technology, and additional rotor system design changes to reduced load and motion requirements should provide the full AH-64 maneuver envelope.

Straub, Friedrich K.; Merkley, Donald J.

1995-05-01

220

Design of a smart material actuator for rotor control  

NASA Astrophysics Data System (ADS)

The results of a study to conceptually define an on-blade smart material actuator for primary and active control on a servoflap rotor are presented. Actuator design drivers, goals, and requirements are defined. For a previously developed hybrid actuator concept, the design of the cyclic and active (high speed) control actuator and feasibility of the collective (low speed) actuator and stroke multiplier are investigated. Sizing of actuator components based on AH-64 servoflap requirements shows that collective control using shape memory alloys is well within the capability of the material. Cyclic and active control using magnetostrictive material, leads to a reduced maneuver envelope due to weight and volume constraints. The promise of smart materials can be realized incrementally as the materials and actuator design approaches mature. Future improvements in smart material performance and actuator technology, and additional rotor system design changes to reduce load and motion requirements should provide the full AH-64 maneuver envelope.

Straub, Friedrich K.; Merkley, Donald J.

1997-06-01

221

Double Negative Materials (DNM), Phenomena and Applications.  

National Technical Information Service (NTIS)

In this document we examine recent developments in double negative materials (DNM) or negative index of refraction materials (NIR) and consider their potential military applications. These materials are artificially engineered, composite structures that p...

B. Balko J. Biddle J. Franklin

2009-01-01

222

Design of electromagnetic actuators using optimizing material distribution methods  

Microsoft Academic Search

This paper deals with the design of electromagnetic actuators via topology optimization methods. It focuses on the development of an optimizing material distribution tool based on a genetic algorithm, the NSGA-II. The originality of this tool is to use a material distribution formalism based on Voronoi cells and to allow not only the material, but also the number and position

B. Dehez; J. Denies; H. Ben Ahmed

2008-01-01

223

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

224

Microdisharges: novel designs and novel materials  

NASA Astrophysics Data System (ADS)

Following an initial surge in microdischarge applications, research in this area has followed two main approaches, with one approach focused on expanding the range of applications for both new and existing devices and the other approach concentrating on understanding the basic physics underlying device operation in these small-volume, high-pressure discharge devices. Despite the application of increasingly sophisticated diagnostic methods, there are still many areas where understanding is, at best, limited. The research reported here centres on understanding the importance of the materials used to fabricate microplasma devices, focusing on the operational behaviour of microhollow cathode discharges. We operate a range of devices that include discharges constructed from simple metal-insulator-metal sandwich structures, Si-SiO2-metal devices fabricated on silicon wafers and, most interestingly, diamond-diamond-metal devices fabricated using a combination of diamond CVD deposition and microlithography. We report on the effect of materials on device ignition, breakdown voltage, and IV characteristics, and we make tentative conclusions about device lifetimes. We will also report on new work involving novel geometries for microhollow cathode discharges, including multi- electrode devices.

Bowden, Mark

2011-11-01

225

Material Design, Selection, and Manufacturing Methods for System Sustainment  

SciTech Connect

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

David Sowder, Jim Lula, Curtis Marshall

2010-02-18

226

Material design of aerated concrete—An optimum performance design  

Microsoft Academic Search

An optimum design for Autoclaved Aerated Concrete (AAC) panel is proposed on the basis of the performance requirements for\\u000a dwellings. With bulk density representing “property” as an intensive variable and thickness of the wall representing “quantity”\\u000a as an extensive variable. Performance requirements such as cost, thermal, acoustic insulation and structural safety are illustrated\\u000a in terms of bulk density d and

S. Tada

1986-01-01

227

Center for Intelligent Fuel Cell Materials Design  

SciTech Connect

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

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

2008-08-26

228

Decision support system for material handling and packaging design  

NASA Astrophysics Data System (ADS)

The reliability of the materials handling process involving automated stacking of packages on a pallet or automated sorting of packages in a distribution system depends mainly on the design of the package and the material used for the package. Many problems can be eliminated that result in a higher utilization of the system if the package is designed not only for the product and its requirements but also for an automated handling system with different types of grasping devices. A decision support system is being developed to help the package designer select the most appropriate material and design to satisfy the requirements of the automated materials handling process. The decision support system is programmed in C++ which gives the flexibility and portability needed for this type of system. The user interface is using graphics to ease the understanding of different design options during the selection process.

Johnsson, Mats I.; Mazouz, Abdel K.; Han, Chingping

1992-02-01

229

Photovoltaic-module encapsulation design and materials selection: Volume 1  

SciTech Connect

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

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

1982-06-01

230

Design for product retirement and material life-cycle  

Microsoft Academic Search

Life-cycle design seeks to maximize the life-cycle value of a product at the early stages of design, while minimizing cost and environmental impact. This paper focuses on product retirement and advanced planning for material recycling. Design for Product Retirement (DFPR) applies to retirement strategies, i.e., designers' intent for product disassembly and reprocessing of subassemblies and components. The method combines quantitative

Kosuke Ishii; Charles F. Eubanks; P DIMARCO

1994-01-01

231

Fundamental Understanding and Theoretical Design of Novel Nanostructured Semiconductor Materials.  

National Technical Information Service (NTIS)

This research was for the fundamental understanding and theoretical design of novel nanostructured semiconductor materials with a potential impact in the areas of thermoelectrics, solar energy, and the role of impurities and embedded nanoparticles. The mo...

A. J. Freeman H. Peng J. Medvedeva J. Song M. S. Park

2012-01-01

232

Evaluation of Materials and Design Modifications for Aircraft Brakes.  

National Technical Information Service (NTIS)

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...

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

1975-01-01

233

Generation of highly directional beam by k-space filtering using a metamaterial flat slab with a small negative index of refraction  

NASA Astrophysics Data System (ADS)

The authors show how a flat slab made of a metamaterial engineered to have a small negative index of refraction can be used to reshape radiation emitted from an isotropic source and produce a highly directional output beam. The slab makes a filtering of high transverse wave vectors of the input diverging beam. The predicted phenomenon is demonstrated at microwave frequencies using a two-dimensional photonic crystal made of alumina rods. Simulations using the finite-difference time-domain method support the experiments.

Martínez, Alejandro; Piqueras, Miguel A.; Martí, Javier

2006-09-01

234

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

235

Designing learning material for Digital Inclusion to elderly People  

Microsoft Academic Search

This paper is about the development of learning material concerning the use of computers, basic software tools and internet services specially designed for third age people. The project, called Infocenter for the third age, has involved 12 elderly people, who participated voluntarily with suggestions for the contents in the first version of the material. The main goal in the project

Márcia Barros de Sales; Ricardo Azambuja Silveira

236

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

ERIC Educational Resources Information Center

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

Dubocq, Edward R.

237

Design, synthesis, and evaluation of materials for microelectronics applications  

Microsoft Academic Search

The advancement of the microelectronics industry is heavily dependent on the design, synthesis, and integration of new materials. Non-chemically amplified photoresists (NCAR) consist of a base resin and photoactive additive which inhibits the dissolution of the this resin. The robustness of NCARs has made them well suited to the unique material requirements of the photomask making industry for many years.

William Hoy Heath

2006-01-01

238

Design of resonators using materials with negative refractive index  

Microsoft Academic Search

By optimizing the design we show that inhomogeneous electromagnetic\\u000aresonators with almost uniform field intensity and up to twice the energy\\u000adensity of conventional structures are possible by exploiting the properties of\\u000anegative refractive index materials. materials. We demonstrate that using\\u000anegative refractive index materials it is possible to make full width at half\\u000amaximum (FWHM) of the transmission coefficient

Petra Schmidt; Ilya Grigorenko; A. F. J. Levi

2007-01-01

239

Design of a smart material actuator for rotor control  

Microsoft Academic Search

The results of a study to conceptually define an on-blade smart material actuator for primary and active control on a servoflap rotor are presented. Actuator design drivers, goals, and requirements are defined. For a previously developed hybrid actuator concept, the design of the cyclic and active (high speed) control actuator and feasibility of the collective (low speed) actuator and stroke

Friedrich K. Straub; Donald J. Merkley

1995-01-01

240

Design of a smart material actuator for rotor control  

Microsoft Academic Search

The results of a study to conceptually define an on-blade smart material actuator for primary and active control on a servoflap rotor are presented. Actuator design drivers, goals, and requirements are defined. For a previously developed hybrid actuator concept, the design of the cyclic and active (high speed) control actuator and feasibility of the collective (low speed) actuator and stroke

Friedrich K. Straub; Donald J. Merkley

1997-01-01

241

Materials and techniques for electrochemical biosensor design and construction  

Microsoft Academic Search

New developments in biosensor design are appearing at a high rate as these devices play increasingly important roles in daily life. This review aims to highlight recent developments in materials and techniques for electrochemical biosensor design and construction. Rapid growth in biomaterials, especially the availability and application of a vast range of polymers and copolymers associated with new sensing techniques

S. Zhang; G. Wright; Y. Yang

2000-01-01

242

Designing optical elements from isotropic materials by using transformation optics  

SciTech Connect

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

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

2010-03-15

243

Ferromagnetic wire lattice with a tunable negative index of refraction for microwaves using an external magnetic field  

Microsoft Academic Search

A new structure of negative-refractive-index material is proposed, which is composed of ferromagnetic wires setting in two-dimensional Bravais lattice (FWL) with the application of external magnetic field. The refractive index of the FWL consisting of ferrum wires arranged in square lattice is calculated. The refractive index exhibits negative value in the GHz region. A notable characteristic of the FWL is

Yun-Song Zhou; Ben-Yuan Gu; Fu-He Wang

2006-01-01

244

Broadband, low-loss negative-permeability and negative-index media for free-space applications  

Microsoft Academic Search

We present broadband negative permeability and negative-refractive-index (NRI) media that operate in free space. Both of these media operate at X-band frequencies and are fabricated using standard printed-circuit-board techniques. The S-parameters of four-cell slabs of the negative permeability and NRI media are measured using a quasi-optical Gaussian beam measurement system. Using these data, the material parameters of the NRI lens

Scott M. Rudolph; Anthony Grbic

2009-01-01

245

68 FR 46428 - Revised Requirement for Material Strength Properties and Design Values for Transport Airplanes  

Federal Register 2010, 2011, 2012, 2013

...Requirement for Material Strength Properties and Design Values for Transport Airplanes; Final...Requirement for Material Strength Properties and Design Values for Transport Airplanes AGENCY...material strength properties and material design values. It incorporates changes...

2003-08-05

246

67 FR 4318 - Revised Requirement for Material Strength Properties and Design Values for Transport Airplanes  

Federal Register 2010, 2011, 2012, 2013

...Requirement for Material Strength Properties and Design Values for Transport Airplanes and Notice...Requirement for Material Strength Properties and Design Values for Transport Airplanes AGENCY...material strength properties and material design values requirement for transport...

2002-01-29

247

Materials by design. A hierarchical approach to the design of new materials  

SciTech Connect

Major developments in materials characterization instrumentation over the past decade have helped significantly to elucidate complex processes and phenomena connected with the microstructure of materials and interfacial interactions. Equally remarkable advances in theoretical models and supercomputers also have been taking place during this period. These latter now permit, for example, in selected cases the computation of material structures, bonding and the prediction of some material properties. Two assessments of the state-of-the-art of instrumental techniques and theoretical methods for the study of material structures and properties have recently been conducted. This paper discusses aspects of computational theoretical methods applied to materials from these assessments. In addition, an approach is presented which uses advanced instrumentation and complementary theoretical computational techniques in tandem in an effort to construct and verify hierarchies of models to translate engineering materials performance requirements into microscopic and atomic level materials specifications (compositions, structure and bonding). Areas of practical interest include: catalysis, tribology (contacting surfaces in relative motion), protective coatings and metallurgical grain boundaries. A first attempt involving modeling of grain boundary adhesion in Ni/sub 3/Al is discussed.

Eberhardt, J.J.; Hay, P.J.; Carpenter, J.A. Jr.

1985-01-01

248

Effective Materials Properties of Interconnections in Industrial Microprocessor Designs  

NASA Astrophysics Data System (ADS)

This talk presents a methodology to evaluate tradeoffs between technology and design to obtain the highest performance in industrial VLSI designs [1]. It is well known that the most significant circuitry constraint is that signals must arrive on time. Since the design cycle is time-consuming and complex, there is a need to migrate designs to future technology nodes to amortize design cost. However, models do not exist [1] to guide designers in their evaluation of whether migrated designs will operate successfully in a future technology or whether migrated designs will cause chip failure. There is therefore a need to evaluate the impact of design changes on performance. This talk evaluates this impact and describes it as an effective change in material properties of the design interconnections. Model estimates are compared with industrial microprocessor design data [1]. References [1] M. Y. Lanzerotti, G. Fiorenza, R. Rand, "Impact of interconnect length changes on effective materials properties (dielectric constant)," Proc. Ninth International ACM Workshop on System-Level Interconnect Prediction (SLIP 2007), Austin, TX, USA, March 17-18, 2007. Online: http://www.informatik.uni-trier.de/˜ley/db/conf/slip/slip2007.html, current as of 11-16-2010.

Lanzerotti, Mary; Fiorenza, Giovanni; Rand, Rick

2011-03-01

249

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

250

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

2011-09-05

251

Teaching-Material Crystallization: Wiki-based Rapid Prototyping for Teaching-Material Design  

Microsoft Academic Search

To support individualized and adaptive learning, teachers are encouraged to develop various teaching materials according to different requirements. However, traditional methodologies for designing teaching materials are time-consuming. To speed up the development process of teaching materials, our idea is to use a rapid prototyping approach which is based on automatic draft generation and Wiki-based revision. Since the Wiki-based authoring is

Wen-Chung Shih; Shian-Shyong Tseng; Jui-Feng Weng

252

Materials and design technology -- 1995. PD-Volume 71  

Microsoft Academic Search

Composite materials, their micromechanics, macromechanics, manufacturing, fabrication, design, failure, and applications continues to be the strong focal point of the symposium. In this year`s symposium two major sessions containing over sixteen research papers are devoted to these very aspects of the composite technology. However, the symposium papers also cover such topics as cold reliability of alloys, silicon microimplants, their fabrication

T. J. Kozik; K. S. Surana

1995-01-01

253

Design of piezocomposite materials and piezoelectric transducers using topology optimization  

Microsoft Academic Search

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

Emilio Carlos Nelli Silva

1998-01-01

254

Silicone materials in new high temperature liquid transformer designs  

Microsoft Academic Search

This paper is a general review of past and current work on the use of silicone materials in high temperature transformer applications. Though the concept of using silicone fluid and Nomeg(R) aramid fiber based solid insulation has been proven technically feasible, commercial acceptance has been limited by a reluctance to change from traditional designs for many power applications. Silicone fluid

James L. Goudie

1997-01-01

255

Materials-based receptors: design principle and applications.  

PubMed

This review focuses on recent developments and growth potential in colorimetric and/or fluorimetric chemosensors based on rationally designed materials and suitable for use in highly selective and sensitive naked-eye detection of environmental and biological analytes. PMID:23606221

Singh, Kamaljit; Sareen, Divya; Kaur, Paramjit; Miyake, Hiroyuki; Tsukube, Hiroshi

2013-04-18

256

The psychophysical approach to manual materials handling task design.  

PubMed

For approximately three decades, researchers have utilized psychophysics to develop guidelines (weights, forces and frequencies) for manual materials handling tasks. Early work by Stover Snook and his colleagues provided the foundations of the experimental methodologies that would be used by other researchers as well as design data that would be used by practitioners. Currently, there are extensive psychophysical data for designing a variety of materials handling tasks. The current state of psychophysical data will be examined, and the psychophysical approach will be compared to the biomechanical and physiological approaches to setting limits for materials handling tasks. The advantages and disadvantages of the psychophysical approach will be discussed, as will the research needs required to address the current limitations of the psychophysical approach. PMID:9973869

Ayoub, M M; Dempsey, P G

1999-01-01

257

46 CFR 160.176-6 - Procedure for approval of design or material revision.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Procedure for approval of design or material revision. 160.176-6 ...160.176-6 Procedure for approval of design or material revision. (a) Each change in design, material, or construction must be...

2011-10-01

258

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Procedure for approval of design or material revision. 160.077-7 ...160.077-7 Procedure for approval of design or material revision. (a) Each change in design, material, or construction of an...

2011-10-01

259

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

Code of Federal Regulations, 2011 CFR

...Procedure for acceptance of revisions of design, process, or materials. 164...Procedure for acceptance of revisions of design, process, or materials. (a) The manufacturer shall not change the design, material, manufacturing...

2011-10-01

260

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

Code of Federal Regulations, 2012 CFR

...acceptance of revisions of design, process, or materials. (a...change the design, material, manufacturing process, or construction of a...revisions in design, material, manufacturing process, or construction of a...

2012-10-01

261

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

SciTech Connect

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

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

1998-08-01

262

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

263

Gradient-index ophthalmic lens design and polymer material studies  

NASA Astrophysics Data System (ADS)

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

Fischer, David Joel

264

Photovoltaic module encapsulation design and materials selection. Volume II  

SciTech Connect

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

Cuddihy, E.

1984-06-01

265

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

NASA Astrophysics Data System (ADS)

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

Fudouzi, Hiroshi

2011-12-01

266

Designing and Planning of Material Handling Systems for Mass Customization  

Microsoft Academic Search

\\u000a Mass customization (MC) involves the challenge of high product proliferation and frequent production volumes change. Flexible\\u000a manufacturing has been treated as the main solution for these challenges. However, without a flexible material handling system\\u000a (MHS), flexible manufacturing cannot be implemented successfully. Therefore, the designing and planning of the flexible MHS\\u000a has attracted intensive research. This chapter first reviews different types

Neville K. S. Lee; James B. Dai

267

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

268

Designing Graphene-based Thermoelectric materials with Chemical Functionalization  

NASA Astrophysics Data System (ADS)

Graphene has been explored as a thermoelectric (TE) material recently due to its superior mobility and ambipolar nature. However, the extremely high thermal conductivity (?) and only moderate Seebeck coefficient (S) make a graphene monolayer a highly inefficient TE material. Graphene superlattices made with chemical functionalization offer the possibility of tuning both the thermal and electronic properties via nano-patterning of the graphene surface. In this work, we investigate the effects of chemical functionalization on the thermoelectric transport properties of graphene using classical and quantum mechanical calculations. Our calculations show that chemical functionalization can control the power factor by changing the width of the pure graphene region and functionalization configuration, as well as ? depending on the functional groups and functionalization coverage. These results suggest that chemical functionalization could be an efficient route to designing graphene-based TE materials.

Kim, Jeong Yun; Grossman, Jeffrey

2013-03-01

269

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

270

Design And Formability Of A New Composite Material  

NASA Astrophysics Data System (ADS)

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.

2011-05-01

271

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

2012-11-15

272

Engineering and Design: Controlled Low Strength Material With Coal- Combustion Ash and Other Recycled Materials.  

National Technical Information Service (NTIS)

This letter provides information and guidance for design and construction of controlled low strength material (CLSM). CLSM has many applications but has been primarily used as a flowable, self-compacting fill in place of a compacted fill. An example speci...

D. A. Beranek

1996-01-01

273

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

274

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

2007-03-01

275

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

Code of Federal Regulations, 2012 CFR

...for approval of design, material, or construction change. 160.133-23 Section...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND...for approval of design, material, or construction change. (a) Each change in...

2012-10-01

276

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

Code of Federal Regulations, 2012 CFR

...for approval of design, material, or construction change. 160.135-23 Section...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND...for approval of design, material, or construction change. (a) Each change in...

2012-10-01

277

46 CFR 160.170-23 - Procedure for approval of design, material, or construction change.  

Code of Federal Regulations, 2012 CFR

...for approval of design, material, or construction change. 160.170-23 Section...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND...for approval of design, material, or construction change. (a) Each change in...

2012-10-01

278

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

Code of Federal Regulations, 2012 CFR

...for approval of design, material, or construction change. 160.156-23 Section...SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND...for approval of design, material, or construction change. (a) Each change in...

2012-10-01

279

System design for safe robotic handling of nuclear materials  

SciTech Connect

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

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

1996-03-01

280

Experimental Design for Combinatorial and High Throughput Materials Development  

NASA Astrophysics Data System (ADS)

In the past decade, combinatorial and high throughput experimental methods have revolutionized the pharmaceutical industry, allowing researchers to conduct more experiments in a week than was previously possible in a year. Now high throughput experimentation is rapidly spreading from its origins in the pharmaceutical world to larger industrial research establishments such as GE and DuPont, and even to smaller companies and universities. Consequently, researchers need to know the kinds of problems, desired outcomes, and appropriate patterns for these new strategies. Editor James Cawse's far-reaching study identifies and applies, with specific examples, these important new principles and techniques. Experimental Design for Combinatorial and High Throughput Materials Development progresses from methods that are now standard, such as gradient arrays, to mathematical developments that are breaking new ground. The former will be particularly useful to researchers entering the field, while the latter should inspire and challenge advanced practitioners. The book's contents are contributed by leading researchers in their respective fields. Chapters include: -High Throughput Synthetic Approaches for the Investigation of Inorganic Phase Space -Combinatorial Mapping of Polymer Blends Phase Behavior -Split-Plot Designs -Artificial Neural Networks in Catalyst Development -The Monte Carlo Approach to Library Design and Redesign This book also contains over 200 useful charts and drawings. Industrial chemists, chemical engineers, materials scientists, and physicists working in combinatorial and high throughput chemistry will find James Cawse's study to be an invaluable resource.

Cawse, James N.

2002-12-01

281

Variance calculations for materials accounting system design and evaluation  

SciTech Connect

Error propagation/variance calculations are used for establishing alarm limits for materials balance closures. Variance calculations may also be employed in the evaluation of accounting system designs for a proposed facility, as well as for upgrades of existing facilities. Information from such an exercise may be used to allocate resources for system improvements and identify process areas that require strict access or material controls. Simplifying assumptions are normally required since detailed data are not available for proposed facilities and may be difficult to obtain for existing facilities. Transfer, inventory, and measurement data are input into a code that calculates the variance for each term in the materials balance equation. Provision should be made for treatment of measurement correlations and holdup. The results are analyzed to determine major contributors to the total materials balance area (MBA) variance. A sensitivity analysis may be performed to determine the effect of changes in the measurements, measurement errors, or MBA structure. Examples of how variance calculations are used in accounting system analysis are discussed in the paper.

Thomas, K.E.

1987-01-01

282

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

283

ATRP in the design of functional materials for biomedical applications  

PubMed Central

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

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

2013-01-01

284

Connecting drug delivery reality to smart materials design.  

PubMed

Inflated claims to both design and mechanistic novelty in drug delivery and imaging systems, including most nanotechnologies, are not supported by the generally poor translation of these systems to clinical efficacy. The "form begets function" design paradigm is seductive but perhaps over-simplistic in translation to pharmaceutical efficacy. Most innovations show few clinically important distinctions in their therapeutic benefits in relevant preclinical disease and delivery models, despite frequent claims to the contrary. Long-standing challenges in drug delivery issues must enlist more realistic, back-to-basics approaches to address fundamental materials properties in complex biological systems, preclinical test beds, and analytical methods to more reliably determine fundamental pharmaceutical figures of merit, including drug carrier purity and batch-batch variability, agent biodistribution, therapeutic index (safety), and efficacy. PMID:23624177

Grainger, David W

2013-04-24

285

ATRP in the design of functional materials for biomedical applications.  

PubMed

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

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

2011-08-25

286

Molecular design of aminopolynitroazole-based high-energy materials.  

PubMed

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

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

2011-12-09

287

First-principles structural design of superhard materials.  

PubMed

We reported a developed methodology to design superhard materials for given chemical systems under external conditions (here, pressure). The new approach is based on the CALYPSO algorithm and requires only the chemical compositions to predict the hardness vs. energy map, from which the energetically preferable superhard structures are readily accessible. In contrast to the traditional ground state structure prediction method where the total energy was solely used as the fitness function, here we adopted hardness as the fitness function in combination with the first-principles calculation to construct the hardness vs. energy map by seeking a proper balance between hardness and energy for a better mechanical description of given chemical systems. To allow a universal calculation on the hardness for the predicted structure, we have improved the earlier hardness model based on bond strength by applying the Laplacian matrix to account for the highly anisotropic and molecular systems. We benchmarked our approach in typical superhard systems, such as elemental carbon, binary B-N, and ternary B-C-N compounds. Nearly all the experimentally known and most of the earlier theoretical superhard structures have been successfully reproduced. The results suggested that our approach is reliable and can be widely applied into design of new superhard materials. PMID:23534621

Zhang, Xinxin; Wang, Yanchao; Lv, Jian; Zhu, Chunye; Li, Qian; Zhang, Miao; Li, Quan; Ma, Yanming

2013-03-21

288

First-principles structural design of superhard materials  

NASA Astrophysics Data System (ADS)

We reported a developed methodology to design superhard materials for given chemical systems under external conditions (here, pressure). The new approach is based on the CALYPSO algorithm and requires only the chemical compositions to predict the hardness vs. energy map, from which the energetically preferable superhard structures are readily accessible. In contrast to the traditional ground state structure prediction method where the total energy was solely used as the fitness function, here we adopted hardness as the fitness function in combination with the first-principles calculation to construct the hardness vs. energy map by seeking a proper balance between hardness and energy for a better mechanical description of given chemical systems. To allow a universal calculation on the hardness for the predicted structure, we have improved the earlier hardness model based on bond strength by applying the Laplacian matrix to account for the highly anisotropic and molecular systems. We benchmarked our approach in typical superhard systems, such as elemental carbon, binary B-N, and ternary B-C-N compounds. Nearly all the experimentally known and most of the earlier theoretical superhard structures have been successfully reproduced. The results suggested that our approach is reliable and can be widely applied into design of new superhard materials.

Zhang, Xinxin; Wang, Yanchao; Lv, Jian; Zhu, Chunye; Li, Qian; Zhang, Miao; Li, Quan; Ma, Yanming

2013-03-01

289

Designing Meaningful Density Functional Theory Calculations in Materials Science  

NASA Astrophysics Data System (ADS)

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

Mattsson, A. E.

2005-07-01

290

Self assembled materials: design strategies and drug delivery perspectives.  

PubMed

Self assembly of small molecules in complex supramolecular structures provides a new avenue in the development of materials for drug delivery applications. Owing to the low aqueous solubility of various drugs, an effective delivery system is often required to reach sufficient drug bioavailability and/or to facilitate clinical use. Micelles, amphiphilic gels, vesicles (liposomes), nanodisks, cubosomes, colloidosomes, tubules, microemulsions, lipid particles, polyelectrolyte capsules etc. are some of the intriguing structures formed via self assembly. As well as enabling improved solubilization, such materials can be tuned to offer a range of other advantages, including controlled or stimuli sensitive drug release, protection from drug hydrolysis and chemical or enzymatic degradation, a reduction in toxicity, improvement of drug availability, prevention of RES uptake or selective targeting to organelles etc. Such multiple functionalities can be brought together by self assembly of different functional molecules. This route offers a cost effective means of developing drug delivery carriers tailored to specific needs. Our current understanding of the microstructure evolution of self assembled materials will go a long way towards designing/selecting molecules to create well defined structures. We believe that most of the potential resources mentioned above are untapped and that there is a need to further strengthen research in this area to fully exploit their potential. Selective cross linking of core or shell, stimuli sensitive amphiphiles, prodrug amphiphiles, antibody coupled amphiphiles etc. are only some of the new approaches for the development of effective drug delivery systems via self assembly. PMID:23907560

Verma, Gunjan; Hassan, P A

2013-09-25

291

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

292

Materials characterization and design for solar-thermal propulsion  

NASA Astrophysics Data System (ADS)

Solar-thermal propulsion relies on the convection of concentrated solar energy into kinetic energy (in the exhaust gases) in order to provide thrust. Solar radiation is focused into a blackbody cavity in which the heat is absorbed and transferred to the hydrogen fuel through a thermal absorber/heat exchanger. Performance increases are obtained by increasing the efficiency of the absorber, thereby increasing the heat transfer to the hydrogen fuel. The absorber/exchanger itself provides structural properties, which involves the severe structural constraint of needing to withstand the high internal hydrogen pressure. Thus, the absorber/exchanger becomes the critical component in the thruster, and the enabling technology for the development of a successful solar-heated hydrogen propulsion system is a combination of materials and processing. The maximum operating temperature of a solar-thermal propulsion devices is governed primarily by the strength and resistance of hydrogen degradation of the constituent materials at the operating temperature of 3000 K and above. Six candidate refractory materials were selected for investigation with regard to their potential for use in solar-thermal propulsion, with the aim of developing a properties and processing database in advance of designing, fabricating, and testing a solar-powered rocket engine (SPRE).

Delarosa, M. J.; Tuffias, R. H.

1993-11-01

293

Process design of press hardening with gradient material property influence  

SciTech Connect

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

Neugebauer, R. [Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz (Germany); Professorship for Machine Tools and Forming Technology, TU Chemnitz (Germany); Schieck, F. [Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz (Germany); Rautenstrauch, A. [Professorship for Machine Tools and Forming Technology, TU Chemnitz (Germany)

2011-05-04

294

A new design concept for multifunctional fasteners using smart materials  

NASA Astrophysics Data System (ADS)

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

Yoon, Hwan-Sik

2009-03-01

295

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

Code of Federal Regulations, 2013 CFR

...material, workmanship, and design. (a) MSHA will test...intended use. Since all possible designs, arrangements, or combinations...modify the construction and design requirements of components...shall be so designed that the temperatures of the external surfaces,...

2013-07-01

296

Computational materials design of filled tetrahedral compound magnetic semiconductors  

NASA Astrophysics Data System (ADS)

Based on first-principles calculations within the density functional theory, materials design of filled tetrahedral compound magnetic semiconductors is proposed. By using the Korringa-Kohn-Rostoker coherent potential approximation, electronic structures of Mn-doped LiZnAs, LiZnP and LiZnN are calculated. First, by estimating free energy, phase diagrams of these systems are predicted. It is shown that these systems are phase separating systems and favor spinodal decomposition. However, by introducing Li vacancies, spinodal decomposition is strongly suppressed and Mn can be doped up to high concentration. Moreover, the introduced Li vacancies induce ferromagnetic interaction between Mn and thus we can expect high Curie temperature (TC) in these systems. To see the chemical trend, electronic structure and TC of Li(Zn, Cr)As are also calculated.

Sato, K.; Fujimoto, S.; Fujii, H.; Fukushima, T.; Katayama-Yoshida, H.

2012-08-01

297

Optimum mixture design of granular materials reinforced by short fiber  

NASA Astrophysics Data System (ADS)

The strength and deformation characteristics of the granular sand are improved by mixing the flexible short fibers. Many factors such as the mixture ratio, fiber materials, fiber length and orientation affect the improvement effect of the short fiber reinforcement sands. Especially, the mixture ratio of short fiber play very important role for the improvement effect and the mixture design. Although the strength of sand increases by mixing a fiber, excessive mixture reduces that of reinforced sand. In this study, we focused on the relationship between the strength and the mixture ratio of fibers by the triaxial compression experiments and the discrete element simulations. Also, we tried to find the critical point of the improvement effect which would be maximized for the strength of granular sand. As a result, the existence of optimum mixture ratio for the strength of granular sand was confirmed.

Nozoe, Shigeaki; Kaneko, Kenji; Hashizume, Yutaka

2013-06-01

298

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

299

Polyoxometalate clusters, nanostructures and materials: from self assembly to designer materials and devices.  

PubMed

Polyoxometalates represent a diverse range of molecular clusters with an almost unmatched range of physical properties and the ability to form structures that can bridge several length scales. The new building block principles that have been discovered are beginning to allow the design of complex clusters with desired properties and structures and several structural types and novel physical properties are examined. In this critical review the synthetic and design approaches to the many polyoxometalate cluster types are presented encompassing all the sub-types of polyoxometalates including, isopolyoxometalates, heteropolyoxometalates, and reduced molybdenum blue systems. As well as the fundamental structure and bonding aspects, the final section is devoted to discussing these clusters in the context of contemporary and emerging interdisciplinary interests from areas as diverse as anti-viral agents, biological ion transport models, and materials science. PMID:17173149

Long, De-Liang; Burkholder, Eric; Cronin, Leroy

2006-10-30

300

Preconceptual Accelerator-Breeder Design for Fissile Material and Energy Production.  

National Technical Information Service (NTIS)

A preconceptual accelerator-breeder design has been developed with improved capability to produce fissile material and thermal power. These improvements allow the design to have the dual role of fissile material and electricity production. (ERA citation 0...

P. S. K. Lam

1979-01-01

301

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

Code of Federal Regulations, 2013 CFR

...Design Requirements § 36.20 Quality of material, workmanship...suitable materials, is of good quality workmanship, based on sound engineering principles...C of this part. (b) The quality of material,...

2013-07-01

302

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Quality of material, workmanship...Design Requirements § 18.20 Quality of material, workmanship...suitable materials, is of good quality workmanship, based on sound engineering...

2010-07-01

303

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

Code of Federal Regulations, 2010 CFR

...Design Requirements § 36.20 Quality of material, workmanship...suitable materials, is of good quality workmanship, based on sound engineering principles...C of this part. (b) The quality of material,...

2010-07-01

304

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

Code of Federal Regulations, 2010 CFR

...Design Requirements § 36.20 Quality of material, workmanship...suitable materials, is of good quality workmanship, based on sound engineering principles...C of this part. (b) The quality of material,...

2009-07-01

305

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

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Quality of material, workmanship...Design Requirements § 18.20 Quality of material, workmanship...suitable materials, is of good quality workmanship, based on sound engineering...

2009-07-01

306

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

Federal Register 2010, 2011, 2012, 2013

...Dumping; Atchafalaya-West Ocean Dredged Material Disposal Site...designate the Atchafalaya-West Ocean Dredged Material Disposal Site...Atchafalaya River Bar Channel Ocean Dredged Material Disposal Site...Environmental protection, Water pollution control. Dated: June...

2013-06-24

307

DESIGN GUIDELINES FOR STRENGTHENING OF STEEL-CONCRETE COMPOSITE BEAMS WITH HIGH MODULUS CFRP MATERIALS  

Microsoft Academic Search

This paper proposes guidelines for the design and installation of high modulus carbon fiber reinforced polymer (CFRP) materials for strengthening typical steel-concrete composite bridge girders. A flexural model is proposed which can be used for the design including determination of the required geometric configuration and material properties of the composite materials. The design procedure is based on a specified increase

David Schnerch; Mina Dawood; Emmett Sumner; Sami Rizkalla

308

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

309

Dynamic Contact Performance of Rubber Materials for Designing Wiper Blades  

NASA Astrophysics Data System (ADS)

A printer assembly consisting of a pen, wiper with two blades, and wiper blade holder is investigated in this study. The two wiper blades press onto the pen surface via proper dimension interference, while wiping across the pen at a certain speed. A finite element model (FEM) was set up with ANSYS-LSDYNA. The hyper-elastic rubber wiper blades are described by Christensen’s model with n = 1 for the strain energy density function. Dynamic contact forces between the wiper blades and the pen, number of contacts, and the duration of the wiper blades jumping over the pen are numerically simulated. Effects of the mechanical properties of the rubber materials, i.e., the coefficient of the Christensen’s model, C 10, on the dynamic contact performance are investigated. The wiper blades are found to periodically touch and jump off from the pen. For the contact between the front blade and the pen, results show that the average contact forces and the number of the contact will increase with C 10, and for the back wiper blade there exist the same conclusions, except that the jumping duration of the back wiper blade does not decrease steadily, but shows a minimum. These results suggest that a new design with two curved sides of the blade tip could be beneficence.

Jiang, Dazhi; Shu, Dongwei

2009-04-01

310

Design of liquid-crystalline electronic functional materials through nanosegregation  

NASA Astrophysics Data System (ADS)

Conventional liquid-crystalline (LC) semiconductors have been molecules consisting of a ?-conjugated moiety and alkyl chains. For example, phenylterthiophene derivatives bearing alkyl chains exhibit ordered smectic phase at room temperature and are applied to field-effect transistors. In this paper, we report a molecular designs of LC electronic materials based on nanosegregation. Terthiophene derivatives bearing an imdazolium moiety exhibit supremolecular smectic phases, in which hole- and ion-conductive layers are formed separately. In the LC phase, electrochrmism is observed under the application of a DC bias without any electrolyte solutions. In simple side-chain LC polysiloxanes bearing terthiophene pendant groups, suprastructures based on nanosegregation are observed. The presence of flexible sublayers consisting of the polysiloxane backbones can relax the applied strain and decrease defect density, resulting in high hole mobility on the order of 10-2 cm2/Vs. For perylene tetracarboxylic bisimide (PTCBI) derivatives bearing oligosiloxane chains, nanosegregation between the rigid aromatic cores and flexible oligosiloxane chains promotes the formation of columnar and layer structures, in which efficient electron transport is observed. The electron mobility in the columnar phase of the PTCBI derivative bearing four trisiloxane chains exceeds 10-3 cm2/Vs at room temperature.

Funahashi, Masahiro

2012-10-01

311

14 CFR 23.613 - Material strength properties and design values.  

Code of Federal Regulations, 2013 CFR

...statistical basis. (b) Design values must be chosen to...must be shown by selecting design values that ensure material...confidence. (c) The effects of temperature on allowable stresses used for design in an essential...

2013-01-01

312

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

313

Guiding the design and application of new materials for enhancing sustainability performance: Framework and infrastructure application  

Microsoft Academic Search

This paper presents a framework for guiding the design of new materials to enhance the sustainability of systems that utilize these materials throughout their production, use and retirement. Traditionally, materials engineering has focused on the interplay between material microstructure, physical properties, processing, and performance. Environmental impacts related to the system's life cycle are not well integrated into the materials engineering

Gregory A. Keoleian; Alissa M. Kendall; Michael D. Lepech; Victor C. Li

2006-01-01

314

Chemical and Materials Information Management for Sustainable Engineering and Design.  

National Technical Information Service (NTIS)

Topics discussed in these briefing charts are: acquisition life cycle, impact of materials and process information on product lifecycle, chemical and materials dilemma, technology dilemma -- differing, sometimes conflicting perspectives/values, business t...

S. McKnight

2010-01-01

315

Material Design of High-Purpose Glass Discussed.  

National Technical Information Service (NTIS)

The purpose of glass material planning is to obtain new glass promptly. Its analysis and essence is examined. The history of the application of high temperature, high strength materials is discussed with silicon nitride used as the example.

I. Yasui

1987-01-01

316

Geothermal turbines-materials evaluation and design aspects  

Microsoft Academic Search

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

S. Toney; M. Cohen; O. Tuncel

1982-01-01

317

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

318

Role of dislocation theory in the design of engineering materials  

SciTech Connect

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

Morris, J.W. Jr.

1980-06-01

319

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

320

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

Microsoft Academic Search

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

Xuan F. Zha; H. Du

2003-01-01

321

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

322

An approach to materials processing and selection for high-field magnet design  

Microsoft Academic Search

In this paper, the physical principles and design criteria for materials selection for high-field, pulsed magnets is discussed. Selection charts are developed based on the design constraints of minimizing ohmic heating and resisting Lorentz forces. Using the selection charts, the merits of various materials are compared. The effects of processing techniques on the material properties and, therefore, the performance of

J. T. Wood; J. D. Embury; M. F. Ashby

1997-01-01

323

Topology design of material layout in structured composites of high stiffness and strength  

Microsoft Academic Search

General continuous topology design formulations based on families of classical Voigt and Reuss mixing assumptions are developed and applied to solve the multiple material layout problem for the design of high stiffness\\/high strength composites. In the novel design framework, computational homogenization is employed to compute stiffness and strength characteristics of individual composite designs. Alternative design formulations for both high stiffness

C. C. Swan; J. S. Arora

1997-01-01

324

Magnetic characterisation of recording materials: design, instrumentation and experimental methods  

Microsoft Academic Search

The progress being made in the field of magnetic recording is extremely fast. The need to keep this progress going, leads to new types of recording materials which require advanced measurement systems and measurement procedures. Furthermore, the existing measurement methods need to be reviewed as due to the differing morphology of novel materials the conventional way to interpretate the measurement

E. O. Samwel

1995-01-01

325

Enclosed mechanical seal face design for brittle materials{copyright}  

Microsoft Academic Search

Metal carbides are widely used as seal face material due to their hardness and wear resistance. Silicon carbide (SiC) has excellent performance as a seal face material, but it is relatively brittle and may break due to accidental overloads outside the boundary of normal operating conditions. In mechanical seals for nuclear primary coolant pumps, the shattered SiC pieces can get

Marsi

1994-01-01

326

Design of smart composite materials using topology optimization  

Microsoft Academic Search

The topology optimization method is used to find the distribution of material phases that extremizes an objective function (e.g., thermal expansion coefficient, piezoelectric coefficients etc) subject to constraints, such as elastic symmetry and volume fractions of the constituent phases, within a periodic base cell. The effective properties of the material structures are found using a numerical homogenization method based on

O. Sigmund; S. Torquato

1999-01-01

327

New Generation Photonics Materials: Design, Development, Characterization and Applications.  

National Technical Information Service (NTIS)

Recent successes in developing two-photon absorption (2PA) materials and applications have now created significant interest in exploring three-photon absorption (3PA) based novel optical materials and new applications. 3PA-based techniques may exhibit two...

P. N. Prasad G. S. He

2003-01-01

328

Materials science in context using design parameters for musical instruments  

Microsoft Academic Search

Students enrolled in any introductory course in materials science are for the first time confronted with integrating knowledge of mathematics, chemistry and physics to solve a wide variety of, at times, abstract problems. However, fundamental materials science concepts can easily be placed in context, thereby creating an enhanced learning environment. This paper describes one such contextual arena-stringed musical instruments. Any

Kathleen L. Kitto

2003-01-01

329

An integrated knowledge-based system for alternative design and materials selection and cost estimating  

Microsoft Academic Search

Building design and material type used are the two main parameters that have a significant impact on the cost of a building. Therefore, it is important for a cost estimating tool to have a mechanism that allows the designer to perform a rapid `what if' analysis on design alternatives and materials selection at the early planning stage without the accompaniment

Abdulrezak Mohamed; Tahir Celik

1998-01-01

330

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

Code of Federal Regulations, 2012 CFR

...AND SYSTEMS Materials and Pressure Design § 128.220 Class...non-vital systemsâmaterials and pressure design. (a) Except...requirements for materials and pressure design of subchapter F of this... (b) Piping for salt-water service must be of a...

2012-10-01

331

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

332

Computational Design of Novel, Radiation Resistant Fusion Materials  

SciTech Connect

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

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

2003-02-01

333

22 CFR 706.41. - How should business submitters designate business information in materials submitted to OPIC?  

Code of Federal Regulations, 2013 CFR

...business submitters designate business information in materials submitted to OPIC? 706.41. ...business submitters designate business information in materials submitted to OPIC? All business submitters may...

2013-04-01

334

Non-Destructive Inspection and Relationships to Aircraft Design and Materials.  

National Technical Information Service (NTIS)

Because the existence of poor communications and limited rate of integration among materials technologists, design engineers and NDI experts was realized by AGARD, the Structures and Materials Panel took the initiative of organizing a Specialists Meeting ...

1978-01-01

335

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

336

A Proposed Design for a Vocational Instructional Materials Evaluation.  

ERIC Educational Resources Information Center

Before vocational instructional products are adopted for statewide dissemination in South Carolina, they must undergo a field test. An effective field test design incorporates collection of data about the instructional products, the students, and the teachers who use the products. The design of a control group and an experimental group compares…

Reynolds, Amelia B.

337

Curriculum Development, Design, Specification and Assessment and Supplemental Materials.  

ERIC Educational Resources Information Center

This document consists of a workshop presentation on curriculum development, design, specification, and assessment in the engineering classroom. Ten sessions focus on: (1) the format and purpose of the workshop, which is designed to help instructors develop an understanding of the basic principles of curriculum and instruction and the ability to…

McNeill, Barry W.; Bellamy, Lynn

338

Advanced computational research in materials processing for design and manufacturing  

Microsoft Academic Search

The computational requirements for design and manufacture of automotive components have seen dramatic increases for producing automobiles with three times the mileage. Automotive component design systems are becoming increasingly reliant on structural analysis requiring both overall larger analysis and more complex analyses, more three-dimensional analyses, larger model sizes, and routine consideration of transient and non-linear effects. Such analyses must be

Zacharia

1994-01-01

339

A method for optimal design of automotive body assembly using multi-material construction  

Microsoft Academic Search

This paper proposes a new method for designing lightweight automotive body assemblies using multi-material construction with low cost penalty. Current constructions of automotive structures are based on single types of materials, e.g., steel or aluminium. The principle of the multi-material construction concept is that proper materials are selected for their intended functions. The design problem is formulated as a multi-objective

Xintao Cui; Shuxin Wang; S. Jack Hu

2008-01-01

340

15 CFR 922.22 - Development of designation materials.  

Code of Federal Regulations, 2013 CFR

...shall notify the appropriate Regional Fishery Management Council(s) which shall...recommendations and, if appropriate, prepare draft fishery regulations and to submit them to...of the proposed Sanctuary designation. Fishery activities not proposed for...

2013-01-01

341

Advanced optimal design concepts for composite material aircraft repair  

NASA Astrophysics Data System (ADS)

The application of an automated optimization approach for bonded composite patch design is investigated. To do so, a finite element computer analysis tool to evaluate patch design quality was developed. This tool examines both the mechanical and the thermal issues of the problem. The optimized shape is obtained with a bi-quadratic B-spline surface that represents the top surface of the patch. Additional design variables corresponding to the ply angles are also used. Furthermore, a multi-objective optimization approach was developed to treat multiple and uncertain loads. This formulation aims at designing according to the most unfavorable mechanical and thermal loads. The problem of finding the optimal patch shape for several situations is addressed. The objective is to minimize a stress component at a specific point in the host structure (plate) while ensuring acceptable stress levels in the adhesive. A parametric study is performed in order to identify the effects of various shape parameters on the quality of the repair and its optimal configuration. The effects of mechanical loads and service temperature are also investigated. Two bonding methods are considered, as they imply different thermal histories. It is shown that the proposed techniques are effective and inexpensive for analyzing and optimizing composite patch repairs. It is also shown that thermal effects should not only be present in the analysis, but that they play a paramount role on the resulting quality of the optimized design. In all cases, the optimized configuration results in a significant reduction of the desired stress level by deflecting the loads away from rather than over the damage zone, as is the case with standard designs. Furthermore, the automated optimization ensures the safety of the patch design for all considered operating conditions.

Renaud, Guillaume

342

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...

343

Microstructural design of composite materials for crashworthy structural applications  

Microsoft Academic Search

Traditionally, metals are used for crashworthy structural applications, mainly due to their plastic deformation characteristics that enable them to absorb impact energy in a controlled manner. Unlike the metals, polymer composite materials display little plastic deformation characteristics. The use of polymer composites for crashworthy structural applications is a major challenge for the composite community. Current research work clearly suggests that

S Ramakrishna

1997-01-01

344

Molecular design of temperature-responsive polymers as intelligent materials  

Microsoft Academic Search

In recent years, temporal control of drug delivery has been of interest in basic and applied fields as a new approach to achieve improved drug therapies. This new drug delivery may be achieved by utilization of intelligent polymeric materials having the functions of sensing, processing and acting. Stimuli-responsive polymers have been investigated as potential molecular devices to achieve intelligent drug

Teruo Okano

345

Photovoltaic module encapsulation design and materials section, volume 2  

NASA Astrophysics Data System (ADS)

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.

1984-06-01

346

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

347

Molecularly Designed Ultrafine/Nanostructured Materials, volume 351  

NASA Astrophysics Data System (ADS)

Nanostructured materials are usually defined as having some length scale smaller than 100 nm in at least one dimension. An important subset of this group of materials is powders with particle size less than 100 nm, and polycrystalline materials, made by consolidating these powders in such a way as to retain a grain size below this limit. The choice of 100 nm stems from the fact that many physical, optical, and magnetic properties have characteristic lengths in this range. As grain or particle size is reduced below this characteristic length, the properties associated with these phenomena are radically altered. A frequently cited example is the freezing out of mechanisms for generating glissile dislocations. Another reason for expecting remarkable properties in nanostructured polycrystalline materials is the very high proportion of atoms at, or near, grain boundaries (as high as fifty percent or greater for grain sizes below five or ten nanometers). This leads, for example, to very rapid diffusion coupled with very short diffusion distances.

Gonsalves, Kenneth E.; Chow, Gan-Moog; Xiao, Tongsan D.; Cammarata, Robert C.

1994-04-01

348

Design of a scientific probe for obtaining Mars surface material  

NASA Astrophysics Data System (ADS)

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.

1990-11-01

349

A Practical Approach To Preform Design For Different Materials  

SciTech Connect

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

Harrer, Otto; Ruef, Guntram; Buchmayr, Bruno [University of Leoben, Franz Josefstr. 18, A-8700 Leoben (Austria); Sommitsch, Christof [Christian Doppler Laboratory for Materials Modelling and Simulation, University of Leoben, Franz Josefstr. 18, A-8700 Leoben (Austria)

2007-04-07

350

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

PubMed

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

Wang, Yonggang; Xia, Yongyao

2013-06-28

351

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

352

Conceptual Design of a Refractory Materials Propulsion Reactor  

Microsoft Academic Search

A propulsion reactor conceptual design is proposed utilizing current technology, where the performance characteristics are expected to surpass those thought to be the limits for this technology. This would be achieved by using several compatible fuel forms, each near its temperature limit, by fine tuning the theoretical computations, and by utilizing innovative engineering. The fuel consists of metallic uranium in

Salim N. Jahshan; Richard L. Moore; Lynn B. Lundberg

1994-01-01

353

DESIGNING OF COURSE MATERIAL FOR E-LEARNING IN PHOTOGRAMMETRY  

Microsoft Academic Search

Distance learning via the Internet (e-learning) requires good course material and a high degree of interactivity. On the basis of an e- learning course of the European Organisation for Spatial Data Research (EuroSDR, formerly OEEPE) about a photogrammetric research topic various tools for producing the user interface, the knowledge pages, multiple-choice quizzes, and interactive learning programs are described. The applied

J. Höhle

354

Design and processing of porous materials for electronic applications.  

PubMed

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

Willoughby, A F W

2006-01-15

355

(Design and licensing of radioactive material shipping containers)  

SciTech Connect

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

Shappert, L.B.

1987-06-29

356

Design guidelines for the development of digital nutrigenomics learning material for heterogeneous target groups  

Microsoft Academic Search

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 the development of the learning material. These design guidelines, derived from theories on cognitive

Maria C. Busstra; R. J. M. Hartog; Sander Kersten

2007-01-01

357

BIOPRODUCTS OF AUTOMOTIVE ACCESSORIES: RETHINKING DESIGN MATERIALS THROUGH CORNSTARCH, SUGARCANE AND HEMP  

Microsoft Academic Search

Current bioproducts or bio-based products do not only require less energy to produce than petroleum-based products, they are made with renewable sources that engineered from excessive waste and natural local materials. This paper identifies alternative design solutions by suggesting a use of natural materials such as cornstarch, sugarcanes and hemp in designing automotive accessories. Leading automotive industries have focused on

Apisak Sindhuphak

358

Design Elements for the Development of Cancer Education Print Materials for a Latina\\/o Audience  

Microsoft Academic Search

Health educators can help reduce cancer disparities in Latino populations through the creation of effective print materials. In this effort, the National Cancer Institute conducted a comprehensive needs assessment to identify key design elements of cancer education programs and create a cost-effective process that would ensure consistency in the development of materials. This article introduces the Checklist of Design Elements

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

2009-01-01

359

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

360

A comparison of MRI magnet design using a Hopfield network and the optimized material distribution method  

Microsoft Academic Search

Two approaches to device design, the Hopfield network and optimized material distribution (OMD), are compared. The comparison is based on a previously published MRI dipole magnet design problem. Since this problem is already formulated as a material distribution problem, the results focus on the optimization procedures used in the two methods, i.e. the learning algorithm of the Hopfield network versus

D. A. Lowther; W. Mai; D. N. Dyck

1998-01-01

361

Materials Performance Issues in the Design of Fuel Elements for Externally Fueled Thermionic Hybrid Systems  

Microsoft Academic Search

Externally fueled thermionic power systems for space applications require nuclear reactors that are capable of operating under severe conditions. Many reactor design requirements, such as high operating temperature, long lifetime and high power density, place stringent constraints on the materials of fuel element construction. Materials performance issues that impact the design of tungsten clad uranium dioxide fuel elements for these

Russell R. Jensen

1994-01-01

362

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

363

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

SciTech Connect

The bibliography contains citations concerning the various designs, configurations, and materials used in catalytic converters to diminish emissions from automotive, truck, diesel, and off-highway vehicles. Citations examine designs using internal flows and diffuser-monolith flows; the effects of flow maldistribution and steady state heat transfer; and materials, including platinum-palladium, urea-SCR, and copper-zeolite. Light-off and three-way catalysts and those designed for natural gas are emphasized. References also cite air/fuel tests, Taguchi techniques, and European and American standards affecting design and materials. (Contains a minimum of 222 citations and includes a subject term index and title list.)

Not Available

1994-12-01

364

Catalytic converter design and materials. (Bibliography from the global mobility database). Published Search  

SciTech Connect

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

NONE

1996-03-01

365

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

SciTech Connect

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

Not Available

1993-12-01

366

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

SciTech Connect

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

NONE

1997-06-01

367

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

368

Materials and design features for the modular HTGR steam generator  

Microsoft Academic Search

The steam generator for the current modular high temperature gas-cooled reactor (MHTGR) has evolved from a technology basis developed in U.S. and European gas-cooled reactor programs. Typical design features of the MHTGR steam generator are the once-through principle and the helical tube bundle arrangement with helium on the shell side and water\\/steam in the tubes. This paper presents an overview

Basol

1990-01-01

369

The Animation Design of Fusible Material Based on Graphics  

NASA Astrophysics Data System (ADS)

In the animation production process, often of different elements to describe the fusion state, this paper takes the single phase reaction-feldspar fusion in the process of ceramic body as example, adopts graphics in its graphics technology to generate fusion style animation design, and makes use of the software Visual C + + language to realize the formation process showing the ceramics microstructure with animation procedure.

Yang, Yun; Yang, Hongli

370

Development, testing, and evaluation of MHD materials and component designs. Volume 1: Executive summary  

Microsoft Academic Search

Results of studies on gas electrical properties, coal combustion, and MHD materials intended to support the Waltz Mill channel experiments are presented. Materials testing indicated that stabilized zirconia should be an acceptable electrode material. Cyclone coal combustors were studied and designs developed for a Waltz Mill size unit and a 25,000 lb\\/h prototype. The Waltz Mill facility performed in a

W. E. Young

1980-01-01

371

Design of Hospital Material Financial Information Management System Based on ASP.NET Technology  

Microsoft Academic Search

This paper describes and analyzes the network architecture and the function modules of the material financial information management system for hospital. The designs of main modules are described. Hospital material financial information management system based on ASP.NET technology achieves the dynamic management of material financial information, increases timeliness of management, and greatly improves the management efficiency.

Geping Zhou; Yunhua Zhang

2011-01-01

372

New magnetic material impact in electric machine design: high speed operation and reduction of losses  

Microsoft Academic Search

The paper presents electrical actuator design considerations introduced by exploiting new magnetic material characteristics. The materials considered are amorphous alloy ribbons as well as neodymium alloy permanent magnets involving very low eddy current losses. Such materials enable electric machine operation at higher frequencies compared with the standard iron laminations used in the traditional magnetic circuit construction and provide better efficiency.

G. Kalokiris; A. Kladas

2003-01-01

373

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

Microsoft Academic Search

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

Wolfgang Mannstadt

2008-01-01

374

Photovoltaic module encapsulation design and materials selection, volume 1, abridged  

NASA Astrophysics Data System (ADS)

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

Cuddihy, E. F.

1982-09-01

375

Polymerizable semi-fluorinated gemini surfactants designed for antimicrobial materials.  

PubMed

Introduction of biocide monomers during the process of polymerization is one of promising approaches in the development of new permanent non leaching biocide materials. In this perspective, new polymerizable semi-fluorinated gemini surfactants, with quaternary ammonium groups as polar heads and an acrylic function as the polymerizable moiety, were synthesized and tested to evaluate their surface active properties alongside with their antibacterial and antifungal properties. Four microbial strains, known for their implication in nosocomial infections, were used to perform the study: Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans and Aspergillus niger. The biocide efficacy measured by bacterial and fungal growth inhibition expressed as MIC (minimal inhibitory concentration) and MLC (minimal lethal concentration) values was discussed as a function of molecular parameters. As compared to homologue compounds without acrylic part, this study shows that even the introduction of a polymerizable moiety allows to keep remarkable both surfactant and bacteriostatic activities, and allows us to envisage the use of these surfactant monomers to build up advanced biocide materials. Moreover, semi-fluorinated gemini surfactant monomers with an amide connector came out as broad spectrum biocides (against Gram positive and negative bacteria and fungi). PMID:19144354

Caillier, Laurent; Taffin de Givenchy, Elisabeth; Levy, Richard; Vandenberghe, Yves; Geribaldi, Serge; Guittard, Frederic

2008-12-24

376

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

National Technical Information Service (NTIS)

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 modeli...

S. Jia T. M. Nenoff P. Provencio Y. Qiu J. A. Shelnutt

1998-01-01

377

Fabrication of a novel micron scale Y-structure-based chiral metamaterial: Simulation and experimental analysis of its chiral and negative index properties in the terahertz and microwave regimes.  

PubMed

In this report, we describe the fabrication of a chiral metamaterial based on a periodic array of Y-shaped Al structures on a dielectric Mylar substrate. The unit cell dimensions of the Y-structure are approximately 100 microm on a side with 8 microm linewidths. The fabricated Y-structure elements are characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Quantitative elemental analyses were carried out on both the Y-structure, comprised of Al and its oxide, as well as adjacent regions of the underlying mylar substrate using the energy dispersive X-ray spectroscopy (EDS) capability of the SEM. Finite-Difference Time-Domain (FDTD) calculations of the negative index of refraction for a 3D wedge of multiple layers of the 2D metamaterials showed that these metamaterials possess double negative (-mu,-epsilon) electromagnetic bulk properties at THz frequencies. The same negative index of refraction was determined for a wedge comprised of appropriately scaled larger Y-structures simulated in the microwave region. This double negative property was confirmed experimentally by microwave measurements on a 3D wedge comprised of stacked and registered Y-structure sheets. PMID:17457819

Wongkasem, Nantakan; Akyurtlu, Alkim; Marx, Kenneth A; Goodhue, William D; Li, Jin; Dong, Qi; Ada, Earl T

2007-06-01

378

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

Microsoft Academic Search

The present investigation is concerned with the study of pulsed second-harmonic generation under conditions of phase and group velocity mismatch, and generally low conversion efficiencies and pump intensities. In positive-index, nonmetallic materials, we generally find qualitative agreement with previous reports regarding the presence of a double-peaked second harmonic signal, which comprises a pulse that walks off and propagates at the

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

2007-01-01

379

Bridging the Design-Manufacturing-Materials Data Gap: Material Properties for Optimum Design and Manufacturing Performance in Light Vehicle Steel-Intensive Body Structures  

NASA Astrophysics Data System (ADS)

As safety and fuel economy regulations become increasingly more challenging around the world, light vehicle manufacturers are facing increasing pressure to reduce the weight of their vehicles cost effectively while maintaining or improving safety performance. Optimum light vehicle steel body structure weight and performance are achieved when the constraints of design, manufacturing, and material properties are considered simultaneously. ArcelorMittal has invested heavily over the past several years to close the gap between material property knowledge and the inter-relation between material performance and design and manufacturing efficiency. Knowledge gained through this process is presented and the importance of achieving this simultaneous 3-way optimization is illustrated by a lightweight steel door design example from ArcelorMittal's S-in motion catalog of lightweight steel solutions.

Zuidema, Blake K.

2012-09-01

380

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.

2013-09-01

381

Design and Application of Electron-Transporting Organic Materials  

NASA Astrophysics Data System (ADS)

Operating lifetime is the main problem that complicates the use of polymeric light-emitting diodes (LEDs). A class of electron transport (ET) polymers [poly(aryl acrylate) and poly(aryl ether)s] is reported in which moieties with high electron affinities are covalently attached to stable polymer backbones. Devices based on poly(p-phenylenevinylene) (PPV) prepared with these materials exhibited a 30-fold improvement in stability and, in one case, dramatically lower (10 volts versus about 30 volts) operating voltage relative to those having conventional ET layers. The current-carrying capacity of indium tin oxide-PPV-polymeric ET layer-aluminum LEDs was also increased by a factor of 30. These improvements lead to an enhancement in power efficiency of nearly an order of magnitude. Choosing polymers with high glass transition temperatures increases device lifetime.

Strukelj, Marko; Papadimitrakopoulos, Fotis; Miller, Timothy M.; Rothberg, Lewis J.

1995-03-01

382

The Siting and Design of a Manufacturing Facility Using Hazardous Materials  

Microsoft Academic Search

A meaningful freshman engineering design experience course with an interdisciplinary environmental approach was offered at New Jersey Institute of Technology in Spring term 1997 and was taught by faculty from the Chemical and Civil Engineering Departments. The problem assigned was the Siting and Design of a Manufacturing Facility using Hazardous Materials and the process design was for a plant to

E. Golub; D. Hanesian; H. Hsieh; A. J. Perna

383

High-temperature mechanical and material design for SiC composites  

Microsoft Academic Search

Silicon carbide (SIC) fiber reinforced composites (FRCs) are strong potential candidate structural and high heat flux materials for fusion reactors. A concise discussion of the main material and design issues related to the use of SiC FRCs as structural materials in future fusion systems is given in this paper. The status of material processing of SiC\\/SiC composites is first reviewed.

Nasr M. Ghoniem

1992-01-01

384

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.

385

Study of left-handed materials  

Microsoft Academic Search

Left handed materials (LHMs) are artificial materials that have negative electrical permittivity, negative magnetic permeability, and negative index of refraction across a common frequency band. They possess electromagnetic (EM) properties not found in nature. LHMs have attracted tremendous attention because of their potential applications to build the perfect lens and cloaking devices. In the past few years there has been

Jiangfeng Zhou

2008-01-01

386

TOPICAL REVIEW: Rational design of organic electro-optic materials  

NASA Astrophysics Data System (ADS)

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

Dalton, L. R.

2003-05-01

387

Materials study supporting thermochemical hydrogen cycle sulfuric acid decomposer design  

NASA Astrophysics Data System (ADS)

Increasing global climate change has been driven by greenhouse gases emissions originating from the combustion of fossil fuels. Clean burning hydrogen has the potential to replace much of the fossil fuels used today reducing the amount of greenhouse gases released into the atmosphere. The sulfur iodine and hybrid sulfur thermochemical cycles coupled with high temperature heat from advanced nuclear reactors have shown promise for economical large-scale hydrogen fuel stock production. Both of these cycles employ a step to decompose sulfuric acid to sulfur dioxide. This decomposition step occurs at high temperatures in the range of 825°C to 926°C dependent on the catalysis used. Successful commercial implementation of these technologies is dependent upon the development of suitable materials for use in the highly corrosive environments created by the decomposition products. Boron treated diamond film was a potential candidate for use in decomposer process equipment based on earlier studies concluding good oxidation resistance at elevated temperatures. However, little information was available relating the interactions of diamond and diamond films with sulfuric acid at temperatures greater than 350°C. A laboratory scale sulfuric acid decomposer simulator was constructed at the Nuclear Science and Engineering Institute at the University of Missouri-Columbia. The simulator was capable of producing the temperatures and corrosive environments that process equipment would be exposed to for industrialization of the sulfur iodide or hybrid sulfur thermochemical cycles. A series of boron treated synthetic diamonds were tested in the simulator to determine corrosion resistances and suitability for use in thermochemical process equipment. These studies were performed at twenty four hour durations at temperatures between 600°C to 926°C. Other materials, including natural diamond, synthetic diamond treated with titanium, silicon carbide, quartz, aluminum nitride, and Inconel were also tested in the simulator to determine corrosion resistances. The study concluded that boron treated diamonds were not suitable for use in decomposer process equipment. Unacceptable corrosion rates were observed at 600°C and increased linearly with temperature up to 700°C. The boron treated diamonds completely disassociated at temperatures above 700°C. The researcher postulated that the high corrosion rates resulted from diamond carbon having a higher preference for oxygen free radicals formed during the decomposition process. Oxygen free radical concentration also increased as a function of increasing temperature. The study also concluded that natural diamond and synthetic titanium treated diamond were unsuitable for use in decomposer process equipment. The corrosion results were similar to that of the boron treated diamonds. Silicon carbide may have potential for used in decomposer process equipment. No appreciable silicon carbide corrosion was observed and more study is warranted. Small amounts of quartz and aluminum nitride corrosion was observed. Inconel corrosion rates were very high at all temperatures tested.

Peck, Michael S.

388

Ranking the Stars: A Refined Pareto Approach to Computational Materials Design  

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

389

Generating material strength standards of aluminum alloys for research reactors II. Design fatigue curve under non-effective creep condition  

Microsoft Academic Search

Aluminum alloys are frequently used as structural materials for research reactors. The material strength standards, however, such as the yield strength values (Sy), the tensile strength values (Su) and the design fatigue curve—which are needed to use aluminum alloys as structural materials in “design by analysis”—for these materials have not been determined yet. Hence, a series of material tests was

Hirokazu Tsuji; Kenzo Miya

1995-01-01

390

Construction of irradiated material examination facility. Detail design and underground structure construction.  

National Technical Information Service (NTIS)

A detail design of the examination process, the hot cell facility and the annexed facility of the irradiated material examination facility (IMEF) which will be utilized to examine and evaluate physical and mechanical properties of neutron-irradiated mater...

S. G. Ro K. S. Lee Y. H. Herr

1990-01-01

391

Simulation of Reaction for the Design of Energetic Materials, Resistant Coatings, and Laser Protection Devices.  

National Technical Information Service (NTIS)

The objective of this research was the development of theoretical and computational methods to guide the design and characterization of materials relevant to the Air Force. The research centered on the development of new methodology for the simulation of ...

S. Hammes-Schiffer

2006-01-01

392

Design of Materials with Extreme Thermal Expansion Using a Three-Phase Topology Optimization Method.  

National Technical Information Service (NTIS)

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 finds the distrib...

O. Sigmund S. Torquato

1996-01-01

393

Evaluation of critical materials in five additional advance design photovoltaic cells  

NASA Astrophysics Data System (ADS)

Potential material supply constraints due to the large scale deployment of five advanced photovoltaic (PV) cell designs were identified and strategies to reduce the impacts of these production capacity limitations and potential future material are suggested. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large scale use of the technologies. The results of the screening of five advanced v cell designs are presented: (1) indium phosphide/cadmium sulfide; (2) zinc phosphide; (3) cadmium telluride/cadmium sulfide; (4) copper indium selenium; and (5) cadmium selenide photoelectrochemical. Each of these five cells is screened individually. The CMAP methodology, used to identify critical materials, is described. Detailed characterizations of the advanced photovoltaic cell designs, descriptions of additional cell production processes, and the results are presented.

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

1981-02-01

394

Advanced Systems Development - Interior Piping Materials/Configuration. Topical Report, Design Concepts March 1985-October 1986.  

National Technical Information Service (NTIS)

New material and component design concepts were developed for interior distribution of natural gas. The objective was to create safe and reliable piping systems with total installed costs that are competitive with electrical wiring serving the same types ...

U. K. Kashalikar R. C. Sykes

1986-01-01

395

Computational methods for design of organic materials with high charge mobility.  

PubMed

Charge carrier mobility is at the center of organic electronic devices. The strong couplings between electrons and nuclear motions lead to complexities in theoretical description of charge transport, which pose a major challenge for the fundamental understanding and computational design of transport organic materials. This tutorial review describes recent progresses in developing computational tools to assess the carrier mobility in organic molecular semiconductors at the first-principles level. Some rational molecular design strategies for high mobility organic materials are outlined. PMID:20111768

Wang, Linjun; Nan, Guangjun; Yang, Xiaodi; Peng, Qian; Li, Qikai; Shuai, Zhigang

2009-10-14

396

Review and needs assessment of materials designed to prevent tobacco use.  

PubMed Central

Over the past 25 years, numerous educational materials and strategies have been developed for the prevention and control of tobacco use. However, there has been no comprehensive assessment of the available materials designed to educate the public to avoid the use of tobacco. A search for materials and a review process was conducted in the fall of 1993, and a panel of experts reviewed the materials that were collected. In conducting the search, 240 persons and organizations associated with tobacco control efforts across the United States were contacted, and 207 materials were identified and evaluated. All materials were assessed by at least two members of the expert panel. Of the 207 items, 188 were found to be acceptable according to standardized review criteria. The authors drew conclusions about the current availability of tobacco use prevention materials and present recommendations for increasing the availability of materials to community-level and other control programs.

Arkin, E B; Gitchell, J G; Pinney, J M

1995-01-01

397

Design case study for a comparative performance analysis of aerospace materials  

Microsoft Academic Search

Reduction of the life cycle cost of aircraft is the main focus of aerospace material development at the moment. By improving the performance of aluminium alloys and using other material systems such as carbon fibre reinforced plastics (CFRP), the life cycle cost can be reduced. This paper presents a design study of a pressurised fuselage section in aluminium and CFRP,

B. Vermeulen; M. J. L. van Tooren

2006-01-01

398

Writing and Designing Print Materials for Beneficiaries: A Guide for State Medicaid Agencies.  

National Technical Information Service (NTIS)

The Writing and Designing Guide is for people who produce information materials and for those who get involved in other ways, such as planning or field testing or answering questions from people who are using the materials. It is full of practical hints a...

1999-01-01

399

Design and Operation of a MEMS-Based Material Testing System for Nanomechanical Characterization  

Microsoft Academic Search

In situ mechanical characterization of nanostructures, such as carbon nanotubes and metallic nanowires, in scanning and transmission electron microscopes is essential for the understanding of material behavior at the nanoscale. This paper describes the design, fabrication, and operation of a novel microelectromechanical-systems (MEMS)-based material testing system used for in situ tensile testing of nanostructures. The device consists of an actuator

Horacio D. Espinosa; Yong Zhu; Nicolaie Moldovan

2007-01-01

400

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

401

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

402

Solder joint fatigue life of fine pitch BGAs – impact of design and material choices  

Microsoft Academic Search

The impact of design and material choices on solder joint fatigue life for fine pitch BGA packages is characterized. Package variables included die size, package size, ball count, pitch, mold compound, and substrate material. Test board variables included thickness, pad configuration, and pad size. Three thermal cycle conditions were used.Fatigue life increased by up to 6× as die size was

Robert Darveaux; Jim Heckman; Ahmer Syed; Andrew Mawer

2000-01-01

403

Design of nanostructured biological materials through self-assembly of peptides and proteins  

Microsoft Academic Search

Several self-assembling peptide and protein systems that form nanotubes, helical ribbons and fibrous scaffolds have recently emerged as biological materials. Peptides and proteins have also been selected to bind metals, semiconductors and ions, inspiring the design of new materials for a wide range of applications in nano-biotechnology.

Shuguang Zhang; Davide M Marini; Wonmuk Hwang; Steve Santoso

2002-01-01

404

Multimedia and Cognition: Examining the Effect of Applying Cognitive Principles to the Design of Instructional Materials  

ERIC Educational Resources Information Center

|The human cognitive system possesses a finite processing capacity, which is split into channels for various modalities, and learning can be inhibited if any of the cognitive channels is overloaded. However, although the amount of e-learning materials is increasing steadily, the design of instructional material has been largely based on intuition…

Thompson, Nik; McGill, Tanya Jane

2008-01-01

405

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

Microsoft Academic Search

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

Chen Fei; Shen Qiang; Zhang Lianmeng

2008-01-01

406

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

407

Design of nanostructured biological materials through self-assembly of peptides and proteins.  

PubMed

Several self-assembling peptide and protein systems that form nanotubes, helical ribbons and fibrous scaffolds have recently emerged as biological materials. Peptides and proteins have also been selected to bind metals, semiconductors and ions, inspiring the design of new materials for a wide range of applications in nano-biotechnology. PMID:12470743

Zhang, Shuguang; Marini, Davide M; Hwang, Wonmuk; Santoso, Steve

2002-12-01

408

LEARNING PROGRESSIONS TO SUPPORT COHERENCE CURRICULA IN INSTRUCTIONAL MATERIAL, INSTRUCTION, AND ASSESSMENT DESIGN  

Microsoft Academic Search

Topics that receive broad coverage with little integration provide a fragile foundation for integrated knowledge growth. In order to support the development of integrated understanding in science, coherent instructional materials should be developed to emphasize not only the learning of individual topics, but also the connections between ideas and across topics and disciplines. To build coherent instructional materials, designers can

Namsoo Shin; Shawn Y. Stevens; Joseph Krajcik

409

Materials design and related R&D issues for the force-free helical reactor (FFHR)  

Microsoft Academic Search

Materials issues related to the Force-Free Helical Reactor (FFHR) design are presented. In FFHR, which uses the Flibe liquid breeder from the main reason of safety, if there is no need to replace in-vessel materials in the lifetime of 30 years, the reactor can be operated with not only the high safety margin but also a high availability of the

A. Sagara; T Muroga; O Motojima; T Noda; S Tanaka; T Terai; A Kohyama; H Matsui

1998-01-01

410

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

SciTech Connect

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

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

1992-01-01

411

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

SciTech Connect

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

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

1992-01-01

412

Materials design considerations and selection for a large rad waste incinerator  

SciTech Connect

A new incinerator has been built to process self-generated, low level radioactive wastes at the Department of Energy`s Savannah River Site. Wastes include protective clothing and other solid materials used during the handling of radioactive materials, and liquid chemical wastes resulting from chemical and waste management operations. The basic design and materials of construction selected to solve the anticipated corrosion problems from hot acidic gases are reviewed. Problems surfacing during trial runs prior to radioactive operations are discussed.

Vormelker, P.R.; Jenkins, C.F.; Burns, H.H.

1997-01-01

413

An intelligent multi-criteria optimization method for quick and market-oriented textile material design  

Microsoft Academic Search

Owing to various end-uses and good performance\\/cost ratio, the multifunctional textile materials have been significantly developed\\u000a within a decade. Such materials are mostly dedicated to niche or limited markets and used for producing high-valued products.\\u000a Facing the international competition, designers are strongly involved in the development of new advanced materials in order\\u000a to satisfy complex customer requirements and specifications with

Xiaoguang Deng; Xianyi Zeng; Philippe Vroman; Ludovic Koehl

2011-01-01

414

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Penetrations of hulls and watertight bulkheads-materials...and Pressure Design § 128.230 Penetrations of hulls and watertight bulkheads...pressure design. (a) Each piping penetration, in each bulkhead required by...

2012-10-01

415

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

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Penetrations of hulls and watertight bulkheads-materials...and Pressure Design § 128.230 Penetrations of hulls and watertight bulkheads...pressure design. (a) Each piping penetration, in each bulkhead required by...

2009-10-01

416

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

417

Material design optimization for a sport shoe sole by evolutionary computation and FEM analysis  

Microsoft Academic Search

This paper describes the material design optimization for a sport shoe sole by the evolutionary computation coupled with the eigenmode analysis based on finite element method. In the present evolutionary computation, a genetic algorithm assisted by the Kriging response surface model was used for global and efficient optimization. The present study implemented two optimization cases based on equivalent design problem

Koji Shimoyama; Kazuya Seo; Tsuyoshi Nishiwaki; Shinkyu Jeong; Shigeru Obayashi

2010-01-01

418

Design and Development of Curricular Materials. Self-Instructional Text, Volume 1.  

ERIC Educational Resources Information Center

|This self-instructional text presents information on the design and development of curricular materials. Three broad divisions provide a framework for the text. Part I, "Background to Instructional Design," examines the goals of education, psychological bases of instruction, determination of subject matter, and necessary skills in formulating…

Gow, Doris T.

419

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

420

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

SciTech Connect

A thermal/mechanical study has been performed which illustrates the behavior of a fusion reactor first wall and blanket module during a loss of coolant flow event. The relative safety advantages of various material and design options were determined. A generalized first wall-blanket concept was developed to provide the flexibility to vary the structural material (stainless steel vs titanium), coolant (helium vs water), and breeder material (liquid lithium vs solid lithium aluminate). In addition, independent vs common first wall-blanket cooling and coupled adjacent module cooling design options were included in the study. The comparative analyses were performed using a modified thermal analysis code to handle phase change problems.

Merrill, B.J.

1980-01-01

421

Effects of Materials Parameters and Design Details on the Fatigue of Composite Materials for Wind Turbine Blades  

SciTech Connect

This paper presents an analysis of the results of nine years of fatigue testing represented in the USDOE/Montana State University (DOE/MSU) Composite Materials Fatigue Database. The focus of the program has been to explore a broad range of glass-fiber-based materials parameters encompassing over 4500 data points for 130 materials systems. Significant trends and transitions in fatigue resistance are shown as the fiber content and fabric architecture are varied. The effects of structural details including ply drops, bonded stiffeners, and other geometries that produce local variations in fiber packing and geometry are also described. Fatigue tests on composite beam structures are then discussed; these show generally good correlation with coupon fatigue data in the database. Goodman diagrams for fatigue design are presented, and their application to predicting the service lifetime of blades is described.

Mandell, J.F.; Samborsky, D.D.; Sutherland, H.J.

1999-03-04

422

Dissipative structures in left-handed material cavity optics  

Microsoft Academic Search

We study the spatiotemporal dynamics of spatially extended nonlinear cavities containing a left-handed material. Such materials, which have a negative index of refraction, have been experimentally demonstrated recently, and allow for novel electromagnetic behavior. We show that the insertion of a left-handed material in an optical resonator allows for controlling the value and the sign of the diffraction coefficient in

Philippe Tassin; Lendert Gelens; Jan Danckaert; Irina Veretennicoff; Guy van der Sande; Pascal Kockaert; Mustapha Tlidi

2007-01-01

423

Application of the ASME code in designing containment vessels for packages used to transport radioactive materials  

SciTech Connect

The primary concern governing the design of shipping packages containing radioactive materials is public safety during transport. When these shipments are within the regulatory jurisdiction of the US Department of Energy, the recommended design criterion for the primary containment vessel is either Section III or Section VIII, Division 1, of the ASME Boiler and Pressure Vessel Code, depending on the activity of the contents. The objective of this paper is to discuss the design of a prototypic containment vessel representative of a packaging for the transport of high-level radioactive material.

Raske, D.T.; Wang, Z.

1992-07-01

424

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

425

The negative index of refraction demystified  

Microsoft Academic Search

We study electromagnetic wave propagation in media in which the effective relative permittivity and the effective relative permeability are allowed to take any value in the upper half of the complex plane. A general condition is derived for the phase velocity to be oppositely directed to the power flow. That extends the recently studied case of propagation in media for

Martin W. McCall; Akhlesh Lakhtakia; Werner S. Weiglhofer

2002-01-01

426

Photon mass and negative index of refraction  

Microsoft Academic Search

A mathematical expression is established for negative refractive index within the context of non-zero photon rest-mass. From this expression, a key inequality involving the mass in question as a function of wavelength is derived. In addition, an approximate parabolic relationship for the refractive index is obtained.

M. Grado-Caffaro

2007-01-01

427

Optical momentum in negative-index media  

Microsoft Academic Search

The correct form of the energy-momentum tensor in a dielectric has been the subject of a controversy spanning the last hundred years. Three principal forms for the momentum, in particular, have been identified for dispersive media. These are the Abraham, Minkowski and canonical momenta. We investigate whether any of these forms can be distinguished by considering pulses of light incident

Mark G. Scullion; Stephen M. Barnett

2008-01-01

428

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

429

Left Handed Materials Based on Magnetic Nanocomposites.  

National Technical Information Service (NTIS)

A new measurement technique has been proposed to determine the sign of the index of refraction in thin film samples. We have observed signature of negative index in NiFe-SiO2 magnetic granular materials and in NiFe/SiO2 multilayers. However, the signal is...

J. Q. Xiao

2006-01-01

430

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

431

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

PubMed

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

2013-01-01

432

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

SciTech Connect

The purpose of this task was to analyze the materials and mechanical design bases for the new boron carbide safety rod. These analyses included examination of the irradiation response of the materials, chemical compatibility of component materials, moisture considerations for the boron carbide pellets and susceptibility of the rod to corrosion under reactor environmental conditions. A number of issues concerning the mechanical behavior were also addressed. These included: safety rod dynamic response in scram scenarios, flexibility and mishandling behavior, and response to thermal excursions associated with gamma heating. A surveillance program aimed at evaluating the integrity of the safety rods following actual operating conditions and justifying life extension for the rods was also proposed. Based on the experimental testing and analyses associated with this task, it is concluded that the boron carbide safety rod design meets the materials and mechanical criteria for successful operational performance.

Marra, J.C.

1992-04-01

433

Preliminary Design and Investigation of Integrated Compressor with Composite Material Wheel  

NASA Astrophysics Data System (ADS)

An integrated water vapor compressor with composite material wheel is developed and strength analysis using FEM is presented. The design of wound composite material allows for integrating all rotating parts of the drive that may simply reduce to only the rotor of the electrical motor, since no drive shaft is required anymore. This design can reduce the number of parts and mass, which is convenient for engineers to maintain the compressor. The electrical motors are brushless DC motors operating through a frequency drive and apply a torque on the wheels through the materials bonded in the wheel shrouds. This system allows a large amount of compression to be produced in a multi-stage compression setup. To determine the stress and vibration characteristics of this integrated compressor, numerical analysis is carried out using FEM. The simulation result shows that the integrated compressor with composite material wheel can be used in a chiller system where water as a refrigerant.

Wang, Jifeng; Müller, Norbert

2012-06-01

434

Bioactive ceramic-based materials with designed reactivity for bone tissue regeneration  

PubMed Central

Bioactive ceramics have been used clinically to repair bone defects owing to their biological affinity to living bone; i.e. the capability of direct bonding to living bone, their so-called bioactivity. However, currently available bioactive ceramics do not satisfy every clinical application. Therefore, the development of novel design of bioactive materials is necessary. Bioactive ceramics show osteoconduction by formation of biologically active bone-like apatite through chemical reaction of the ceramic surface with surrounding body fluid. Hence, the control of their chemical reactivity in body fluid is essential to developing novel bioactive materials as well as biodegradable materials. This paper reviews novel bioactive materials designed based on chemical reactivity in body fluid.

Ohtsuki, Chikara; Kamitakahara, Masanobu; Miyazaki, Toshiki

2009-01-01

435

Design of an Authoring Tool for Producing User-Adaptive Educational Materials  

NASA Astrophysics Data System (ADS)

The authors are studying a u-learning system called KUSEL, which is characterized by being user-adaptive, a property achieved by using scenario-driven operation and a causal network. While highly flexible in providing user adaptability, KUSEL requires completion of a set or complex tasks for the purpose of creating educational materials. This paper reports on the design of an authoring tool that facilitates the creation of educational materials for KUSEL.

Abe, Satoki; Fujiwara, Yoshitaka; Okada, Shin-Ichirou; Maeda, Yasunari

436

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

437

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

438

Hierarchical bioactive materials for tissue reconstruction: Integrated design and manufacturing challenges  

NASA Astrophysics Data System (ADS)

Although the paradigm shift from synthetic implants and tissue grafts to regenerative-medicine-based tissue reconstruction has been promised for well over a decade, the reality has yet to emerge. A significant reason for this delay is that regenerative medicine reconstruction solutions involve complex systems in which bioresorbable materials are integrated with surface modifications delivering cells and growth factors. These systems must not only fill complex shapes and provide temporary mechanical function; they must deliver biologic factors that stimulate tissue growth in a controlled, safe, yet rapid manner. Finally, the materials should degrade on a timeline matched to the time it takes to grow tissues. As such, these material device systems are multifunctional and require design techniques that can address multifunctionality, coupled with multiple material manufacturing processes that can be integrated to achieve the design. In this paper, we review these design and manufacturing processes as well as the challenges to integrate these multiple design and manufacturing processes to engineer bioactive material devices.

Hollister, Scott J.

2011-04-01

439

Corrosion performance of alternative steam-generator materials and designs. Volume 1. Summary of corrosion tests of alternative materials and designs in two model steam generators. Final report  

SciTech Connect

Corrosion results obtained from the post-test non-destructive and destructive examinations of two alternative-materials model steam generators are summarized and compared in this final report. The models operated under representative thermal and hydraulic and accelerated (high contaminant concentration) steam generator secondary water-chemistry conditions. One model was faulted with seawater to a level of 30 ppM chloride for 282 steaming days; the other model was faulted with concentrated, acidified (H/sub 2/SO/sub 4/) fresh water to a level of 40 ppM sulfate for 358 steaming days. Various support-plate and lattice-strip-support designs incorporated Types 347, 405, 409, and SCR-3 stainless steels; Alloys 600 and 690; and carbon steel. Heat-transfer-tube materials included Alloy 600 in various heat treated conditions, Alloy 690, and Alloy 800.

Krupowicz, J.J.; Rentler, R.M.

1983-07-01

440

Linac Coherent Light Source soft x-ray materials science instrument optical design and monochromator commissioning  

NASA Astrophysics Data System (ADS)

We present the x-ray optical design of the soft x-ray materials science instrument at the Linac Coherent Light Source, consisting of a varied line-spaced grating monochromator and Kirkpatrick-Baez refocusing optics. Results from the commissioning of the monochromator are shown. A resolving power of 3000 was achieved, which is within a factor of two of the design goal.

Heimann, Philip; Krupin, Oleg; Schlotter, William F.; Turner, Joshua; Krzywinski, Jacek; Sorgenfrei, Florian; Messerschmidt, Marc; Bernstein, David; Chalupský, Jaromir; Hájková, Vera; Hau-Riege, Stefan; Holmes, Michael; Juha, Libor; Kelez, Nicholas; Lüning, Jan; Nordlund, Dennis; Fernandez Perea, Monica; Scherz, Andreas; Soufli, Regina; Wurth, Wilfried; Rowen, Michael

2011-09-01

441

Design and control of a heavy material handling manipulator for agricultural robots  

Microsoft Academic Search

In this paper, we propose a manipulation system for agricultural robots that handle heavy materials. The structural systems\\u000a of a mobile platform and a manipulator are selected and designed after proposing new knowledge about agricultural robots.\\u000a Also, the control systems for these structural systems are designed in the presence of parametric perturbation and uncertainty\\u000a while avoiding conservative results. The validity

Satoru Sakai; Michihisa Iida; Koichi Osuka; Mikio Umeda

2008-01-01

442

Design and testing criteria for bipolar plate materials for PEM fuel cell applications  

NASA Astrophysics Data System (ADS)

Bipolar plates for proton exchange membrane (PEM) fuel cells are currently under development. These plates separate individual cells of the fuel cell stack, and thus must be sufficiently strong to support clamping forces, be electrically conducting, be fitted with flow channels for stack thermal control, be of a low permeability material to separate safely hydrogen and oxygen feed streams, be corrosion resistant, and be fitted with distribution channels to transfer the feed streams over the plate surface. To date, bipolar plate costs dominate stack costs, and therefore future materials need to meet strict cost targets. A first step in the bipolar plate development program is an assessment of design constraints. Such constraints have been estimated and evaluated and are discussed here. Conclusions point to promising advanced materials, such as conductive, corrosion resistant coatings on metal substrates, as candidates for mass production of fuel cell bipolar plates. Possible candidate materials are identified, and testing procedures developed to determine suitability of various materials.

Borup, Rodney L.; Vanderborgh, Nicholas E.

443

Design and testing criteria for bipolar plate materials for PEM fuel cell applications  

SciTech Connect

Bipolar plates for proton exchange membrane (PEM) fuel cells are currently under development. These plates separate individual cells of the fuel cell stack, and thus must be sufficiently strong to support clamping forces, be electrically conducting, be fitted with flow channels for stack thermal control, be of a low permeability material to separate safely hydrogen and oxygen feed streams, be corrosion resistant, and be fitted with distribution channels to transfer the feed streams over the plate surface. To date, bipolar plate costs dominate stack costs, and therefore future materials need to meet strict cost targets. A first step in the bipolar plate development program is an assessment of design constraints. Such constraints have been estimated and evaluated and are discussed here. Conclusions point to promising advanced materials, such as conductive, corrosion resistant coatings on metal substrates, as candidates for mass production of fuel cell bipolar plates. Possible candidate materials are identified, and testing procedures developed to determine suitability of various materials.

Borup, R.L.; Vanderborgh, N.E.

1995-05-01

444

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

445

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

446

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

National Technical Information Service (NTIS)

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 Nucl...

J. Hockert T. Bjornard

2011-01-01

447

Strength and design of adhesive joints in cylindrical elements made of metal and reinforced polymeric materials  

Microsoft Academic Search

The present study is a continuation of the research begun in [1]. The designs of adhesive joints formed by winding a steel tip in cross winding of a tube made of reinforced polymeric material (RPM) with an infinite fiber and winding of a layer of RPM on the joint of steel tubes, respectively, are shown in Fig. 1. The practical

B. L. Pelekh; M. V. Marchuk; I. S. Kogut

1992-01-01

448

Aspects of material and design of optimized silicon carbide seal rings  

Microsoft Academic Search

The production of mechanical seal rings made of silicon infiltrated silicon carbide (SiSiC) is described with emphasis on the effect of different topographies on their performance. In particular, attention is given to optimization of the design of the seals for achieving the elastohydrodynamic effect between the sealing faces, and optimization of the microstructure of the sealing face material with regard

J. Heinrich; O. Rosenfelder; W. Benker; H. Schelter

1991-01-01

449

Understanding Naïve Reasonings in Signals and Systems: A Foundation for Designing Effective Instructional Material  

Microsoft Academic Search

Student naive reasonings in an undergraduate engineering course, signals and systems, were investigated in order to provide the groundwork for designing effective instructional material. Students majoring in aerospace engineering at the Massachusetts Institute of Technology were interviewed to probe their reasoning about different signals and systems topics, particularly in their analysis of continuous-time, linear, time-invariant systems using the fundamental properties

Reem Nasr; Steven R. Hall; Peter Garik

2009-01-01

450

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

SciTech Connect

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

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

1995-09-01

451

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

Microsoft Academic Search

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

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

2009-01-01

452

A Study of Learning Performance of E-Learning Materials Design with Knowledge Maps  

ERIC Educational Resources Information Center

|This research investigated the application of knowledge maps in e-learning materials design and hypothesized that knowledge maps would be more effective than e-learning in general at improving the performance and satisfaction of e-learning. In order to test the hypotheses, we conducted an experiment with 175 participants and randomly assigned…

Shaw, Ruey-Shiang

2010-01-01

453

Evaluation of critical materials in five additional advance design photovoltaic cells  

SciTech Connect

The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. The Critical Materials Assessment Program (CMAP) screens the designs and their supply chains and identifies potential shortages which might preclude large-scale use of the technologies. The results of the screening of five advanced PV cell designs are presented: (1) indium phosphide/cadmium sulfide, (2) zinc phosphide, (3) cadmium telluride/cadmium sulfide, (4) copper indium selenium, and (5) cadmium selenide photoelectrochemical. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 Gwe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has a 5 GWe of peak capacity by the year 2000, so that the total online capacity for the five cells is 25 GWe. Based on a review of the preliminary baseline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. The CMAP methodology used to identify critical materials is described; and detailed characterizations of the advanced photovoltaic cell designs under investigation, descriptions of additional cell production processes, and the results are presented. (WHK)

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

1981-02-01

454

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

455

Minimum Cost Design (MCD) Material Screening. Test Report No. 2 - Dow Corning DC93-104.  

National Technical Information Service (NTIS)

This is the second of a series of reports describing the results of test firings conducted to determine the performance of low-cost ablative materials which are candidates for use as thrust chamber and nozzle liners for MCD (Minimum Cost Design) Booster e...

J. A. Hintz

1969-01-01

456

Development of methods for designing structural elements made of structurally heterogeneous materials by developing physicomechanical models  

Microsoft Academic Search

Methods for designing structural elements made of structurally heterogeneous materials by developing vectorial models and\\u000a studying the scale effect of elastic properties have been developed. Results of calculation of stress-strain states with allowance\\u000a for structural and geometric factors of stress and strain concentration are presented.

L. V. Kuksa; L. M. Arzamaskova; E. E. Evdokimov; A. V. Sergeev

2006-01-01

457

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

458

Design of a high frequency switching amplifier for smart material actuators with improved current mode control  

Microsoft Academic Search

A high frequency switching amplifier using current mode control strategy is designed and developed to drive the newly developed smart material actuators. Different from ordinary PWM converters, this kind of switching amplifier typically deals with a reactive load, which usually gives the amplifier a low current loop gain for low frequencies. This low current loop gain usually results in a

Jiyuan Luan; Fred C. Lee

1998-01-01

459

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

460

Color research and its application to the design of instructional materials  

Microsoft Academic Search

This paper is divided into three major sections: Color as Seen—Physiological; Color as Seen—Psychological; and Color and Learning. The first section deals with color adaptations and the effects of color on acuity and relates these to the design of instructional materials. The second section covers color meanings and preferences, as well as color harmony and the relationships of these factors

Dennis Pett; Trudy Wilson

1996-01-01

461

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

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

2008-01-01

462

Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies  

Microsoft Academic Search

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

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

2005-01-01

463

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

Microsoft Academic Search

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

Atul Kumar; Ramana G. Reddy

2004-01-01

464

Design, Development and Space Qualification of a Prototype Phase Change Material Device.  

National Technical Information Service (NTIS)

The small prototype PCM (Phase Change Material) device designed for spacecraft thermal control and having a latent storage capacity of 100 watt-hours, is a hermetically sealed unit made from aluminum alloy, filled with octadecane serving as the PCM and us...

A. Abhat

1975-01-01

465

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

466

Design study of a capacitive pressure sensor in non-silicon materials  

Microsoft Academic Search

This paper reports on the design of a capacitive pressure sensor fabricated in non-silicon materials. The sensor consists of a thin membrane placed parallel to a rigid reference plane. The membrane and the reference plane act as the two electrodes of a capacitor. Deflection of the membrane due to a pressure difference results in a change in capacity. These capacity

M. H. H. Meuwissen; E. P. Veninga; M. W. W. J. Tijdink; M. G. H. Meijerink

2006-01-01

467

Professor Co-Ops: Media Students Design and Develop Instructional Materials with Professors.  

ERIC Educational Resources Information Center

|Undergraduate students enrolled in ten-week media and methods courses in the teacher education program at Valdosta State College are provided the opportunity to work cooperatively on a one-to-one basis with professors in the selection, design, production, and evaluation of instructional materials. (Author)|

Ackerman, Amy S.

1979-01-01

468

Design, synthesis, and optimization of materials for 193 nm and 157 nm photoresists  

Microsoft Academic Search

A series of alicyclic polymers was designed and synthesized for use in 193 nm photoresists. When incorporated into photoresists, polymers containing these alicyclic units are capable of providing dry etch resistance while offering minimal absorbance at 193 nm. Two different polymerization techniques, ring-opening metathesis polymerization (ROMP) and free radical polymerization, were utilized to create these alicyclic materials from cycloolefinic monomers.

Kyle William Patterson

2000-01-01

469

Design length scales for carbon nanotube photoabsorber based photovoltaic materials and devices  

NASA Astrophysics Data System (ADS)

Semiconducting carbon nanotubes are attractive materials for harvesting light in photovoltaic solar cells and photodetectors. A crucial aspect of designing efficient photovoltaic devices using nanotubes is minimizing the length scale for the absorption of light (LA) and maximizing the length scale across which excitons diffuse (LD) in fibers and films of these materials. In order to facilitate the optimization of these parameters, here we model how LA and LD are affected by nanotube bandgap polydispersity, inter-nanotube coupling, film disorder, orientation, and defects. Our models are guided by previous experimental measurements of optical absorption spectra and exciton inter-nanotube transfer rates made on isolated and bundled nanotubes in conjunction with kinetic Monte Carlo simulations. Our results provide criteria for materials selection and the design of efficient carbon nanotube-based light harvesting devices, in various architectures.

Wu, Meng-Yin; Jacobberger, Robert M.; Arnold, Michael S.

2013-05-01

470

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

471

[Design of plant leaf bionic camouflage materials based on spectral analysis].  

PubMed

The influence of structure parameters and contents of plant leaves on their reflectance spectra was analyzed using the PROSPECT model. The result showed that the bionic camouflage materials should be provided with coarse surface and spongy inner structure, the refractive index of main content must be close to that of plant leaves, the contents of materials should contain chlorophyll and water, and the content of C-H bond must be strictly controlled. Based on the analysis above, a novel camouflage material, which was constituted by coarse transparent waterproof surface, chlorophyll, water and spongy material, was designed. The result of verifiable experiment showed that the reflectance spectra of camouflage material exhibited the same characteristics as those of plant leaves. The similarity coefficient of reflectance spectrum of the camouflage material and camphor leaves was 0.988 1, and the characteristics of camouflage material did not change after sunlight treatment for three months. The bionic camouflage material, who exhibited a high spectral similarity with plant leaves and a good weather resistance, will be an available method for reconnaissance of hyperspectral imaging hopefully. PMID:21847955

Yang, Yu-Jie; Liu, Zhi-Ming; Hu, Bi-Ru; Wu, Wen-Jian

2011-06-01

472

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

PubMed

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

Lencer, Dominic; Salinga, Martin; Wuttig, Matthias

2011-04-05

473

Alternative routes for highway shipments of radioactive materials and lessons learned from state designations  

SciTech Connect

Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under docket numbers HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select altemative routes. First, the state must establish a ``state routing agency``, defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with DOTs Guidelines for Selecting Preferred Highway Routes for Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice to DOT of any alternative route designation before the routes are deemed effective. The purpose of this report is to discuss the ``lessons learned`` by the five states within the southern region that have designated alternative or preferred routes under the regulations of the Department of Transportation (DOT) established for the transportation of radioactive materials. The document was prepared by reviewing applicable federal laws and regulations, examining state reports and documents and contacting state officials and routing agencies involved in making routing decisions. In undertaking this project, the Southern States Energy Board hopes to reveal the process used by states that have designated alternative routes and thereby share their experiences (i.e., lessons learned) with other southern states that have yet to make designations.

Not Available

1990-07-01

474

Alternative routes for highway shipments of radioactive materials and lessons learned from state designations  

SciTech Connect

Pursuant to the Hazardous Materials Transportation Act (HMTA), the Department of Transportation (DOT) has promulgated a comprehensive set of regulations regarding the highway transportation of high-level radioactive materials. These regulations, under docket numbers HM-164 and HM-164A, establish interstate highways as the preferred routes for the transportation of radioactive materials within and through the states. The regulations also provide a methodology by which a state may select altemative routes. First, the state must establish a state routing agency'', defined as an entity authorized to use the state legal process to impose routing requirements on carriers of radioactive material (49 CFR 171.8). Once identified, the state routing agency must select routes in accordance with DOTs Guidelines for Selecting Preferred Highway Routes for Large Quantity Shipments of Radioactive Materials or an equivalent routing analysis. Adjoining states and localities should be consulted on the impact of proposed alternative routes as a prerequisite of final route selection. Lastly, the states must provide written notice to DOT of any alternative route designation before the routes are deemed effective. The purpose of this report is to discuss the lessons learned'' by the five states within the southern region that have designated alternative or preferred routes under the regulations of the Department of Transportation (DOT) established for the transportation of radioactive materials. The document was prepared by reviewing applicable federal laws and regulations, examining state reports and documents and contacting state officials and routing agencies involved in making routing decisions. In undertaking this project, the Southern States Energy Board hopes to reveal the process used by states that have designated alternative routes and thereby share their experiences (i.e., lessons learned) with other southern states that have yet to make designations.

Not Available

1990-07-01

475

Criteria for design with structural materials in combined-cycle applications above 815[degree]C  

SciTech Connect

A number of materials issues related to the design of piping and support components in high-temperature fluidized bed combustor systems are examined. These issues include the availability of long-time design data on structural materials, the general character of the creep and stress rupture behavior, the performance of weldments, and the assessment of damage accumulation. Emphasis is placed on alloy 800H, but several other alloys were briefly examined for use at temperature above 816 C (1,500 F). The paper concludes that the character of the creep curve ranged significantly with chemistry, processing variables, and environment, and that the specification of design allowable stresses and life estimation techniques must be approached with caution for service above 816 C (1,500 F).

Swindeman, R.W. (Oak Ridge National Lab., TN (United States)); Marriott, D.L. (Stress Engineering Services, Cincinnati, OH (United States))

1994-04-01

476

Design of a cryogenic absolute prism refractometer for infrared optical materials  

NASA Astrophysics Data System (ADS)

In order to enable high quality infrared lens designs at cryogenic temperature, we decided to study the IR materials' optical properties, such as the refractive index, the thermo-optic coefficient (dn/dT) etc. As a matter of fact, accurate precision refractive index data for infrared optical materials at cryogenic temperatures is scarce, so we decided to design a cryogenic absolute prism refractometer for infrared optical materials. Considering the most accurate and precise measurements of the real part of the refractive index, n, optical materials are obtained through minimum deviation refractometry, we decided to choose this classic refractometer for our cryogenic IR materials index measuring. Given the thermo-optic coefficient of many IR materials, which was reported by NASA, the measurement precision is at least 10-3. In order to achieve this precision, the error of apex angle of sample prism and deviation angle must be less than 20 arc-second. The thermal stress of the prism must be in control, or the volume change of the prism may lead to stress birefringence (photo-elastic effect). The bandwidth of IR source must be less than 20nm and the error caused by dispersion (dn/d?) will generally be negligible in our system. The hardware system consists of 5 subsystems: the rotating sample chamber subsystem, the rotating plat mirror subsystem, the cryogenic vacuum subsystem, auto control subsystem, exit image collimation subsystem. Finally, the system is designed to measure IR materials' indices between 1-4, at the wavelength of 1.0-12?m, at room (300K) and cryogenic temperature (100K), with a precision of 10-4.

Liao, Sheng; Ni, Lei; Ren, Qi-Feng

2011-08-01

477

Synthesis of designed materials by laser-based direct metal deposition technique: Experimental and theoretical approaches  

NASA Astrophysics Data System (ADS)

Direct metal deposition (DMD), a laser-cladding based solid freeform fabrication technique, is capable of depositing multiple materials at desired composition which makes this technique a flexible method to fabricate heterogeneous components or functionally-graded structures. The inherently rapid cooling rate associated with the laser cladding process enables extended solid solubility in nonequilibrium phases, offering the possibility of tailoring new materials with advanced properties. This technical advantage opens the area of synthesizing a new class of materials designed by topology optimization method which have performance-based material properties. For better understanding of the fundamental phenomena occurring in multi-material laser cladding with coaxial powder injection, a self-consistent 3-D transient model was developed. Physical phenomena including laser-powder interaction, heat transfer, melting, solidification, mass addition, liquid metal flow, and species transportation were modeled and solved with a controlled-volume finite difference method. Level-set method was used to track the evolution of liquid free surface. The distribution of species concentration in cladding layer was obtained using a nonequilibrium partition coefficient model. Simulation results were compared with experimental observations and found to be reasonably matched. Multi-phase material microstructures which have negative coefficients of thermal expansion were studied for their DMD manufacturability. The pixel-based topology-optimal designs are boundary-smoothed by Bezier functions to facilitate toolpath design. It is found that the inevitable diffusion interface between different material-phases degrades the negative thermal expansion property of the whole microstructure. A new design method is proposed for DMD manufacturing. Experimental approaches include identification of laser beam characteristics during different laser-powder-substrate interaction conditions, an investigation of extended solubility in multi-material laser cladding, and a study of DMD manufacturing technology for its impact on energy and environment with the comparison of traditional machining process. Experimental results show the feasibility of depositing multiple materials at arbitrary compositions and forming clad with unlimited solubility and uniform distribution in DMD process. DMD technology presents great potential for reducing energy consumption and environmental impact in parts repairing/remanufacturing and situations where the part to be built has small solid-to-cavity volume ratio.

Qi, Huan

478

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

SciTech Connect

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

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

2008-06-01

479

Army Aircraft Protective Structures Designs. Report 3. Response of Selected Materials to High-Speed Fragment Impact.  

National Technical Information Service (NTIS)

In order to design effective fragment protection schemes that will allow optimum use of time, personnel, and materials, it is necessary to understand the behavior of various materials under fragment impact. Therefore, a study has been conducted using text...

J. W. Brown W. G. Dykes

1971-01-01

480

Characterization of Unbound Pavement Materials From Virginia Sources for Use in the New Mechanistic-Empirical Pavement Design Procedure.  

National Technical Information Service (NTIS)

The implementation of mechanistic-empirical pavement design requires mechanistic characterization of pavement layer materials. The subgrade and base materials are used as unbound, and their characterization for Virginia sources was considered in this stud...

M. S. Hossain

2010-01-01