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1

Propagation of electromagnetic solitons in nonlinear negative-index materials  

Microsoft Academic Search

The propagation property of electromagnetic solitons in the negative-index material with a nonlinear polarization is investigated numerically. The role of the negative self-steepening and the higher-order nonlinear dispersion effects, which are resulted from the dispersive permeability of negative-index material, in soliton propagation is identified. It is shown that, like the positive self-steepening effect, the negative self-steepening effect also leads to

Xiaoyan Song; Shuangchun Wen

2006-01-01

2

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

3

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

4

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

E-print Network

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

5

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

E-print Network

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

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

2013-01-01

6

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

SciTech Connect

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

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

2013-09-30

7

Gray solitary-wave solutions in nonlinear negative-index materials Penggang Li,1  

E-print Network

in negative-index materials on the basis of a derived higher-order nonlinear Schrödinger equation-index materials. The results show that the higher-order linear and nonlinear effects play a crucial role dispersion TOD and second-order nonlinear dispersion effects, which describes the propagation of few

8

Theoretical investigation of modulation instability in a three-core coupler with negative index material channel  

NASA Astrophysics Data System (ADS)

We investigate the modulation instability (MI) in a three-core oppositely-directed coupler with a particular emphasis on a negative index material (NIM) channel. In order to give a comprehensive picture, we consider the normal and the anomalous dispersion regimes. Special attention is paid to investigation of the influence of system parameters such as the power and the coupling coefficient on the MI. We also analyze the impact of different nonlinear configurations of coupler channels on MI.

Shafeeque Ali, A. K.; Nithyanandan, K.; Porsezian, K.

2015-01-01

9

Resonant modes and inter-well coupling in photonic quantum well with negative index materials  

NASA Astrophysics Data System (ADS)

The transfer matrix method was used to study the resonant modes in photonic quantum well by stacking different photonic crystals consisting of positive index materials and negative index materials. The eigenfrequency equation for the resonant modes is derived. It is found that these resonant modes are omnidirectional, and the number of resonant modes is equal to the period number of photonic quantum wells. Moreover, the resonant modes become N-fold splitting in the N photonic quantum wells. The splitting intervals increase with the deceasing of photonic barrier thickness due to the coupling among the wells.

Yin, C.-P.; Dong, J.-W.; Wang, H.-Z.

2009-01-01

10

A subwavelength near-infrared negative index material Xuhuai Zhang, Marcelo Davano, Yaroslav Urzhumov, Gennady Shvets, and Stephen R. Forrest  

E-print Network

A subwavelength near-infrared negative index material Xuhuai Zhang, Marcelo Davanço, Yaroslav://scitation.aip.org/termsconditions. Downloaded to IP: 129.116.140.116 On: Thu, 13 Mar 2014 15:08:47 #12;A subwavelength near-infrared negative.1063/1.3110957 Negative index materials NIMs 1,2 have recently been reported at near-infrared or higher optical

Texas at Austin, University of

11

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

12

Non-Bragg bandgaps of quasi-one-dimensional comb-like structures composed of positive and negative index materials  

NASA Astrophysics Data System (ADS)

Quasi-one-dimensional comb-like periodic and aperiodic structures composed of positive index materials branch resonators and negative index materials backbone waveguide are physically fabricated by using transmission line approach. It is theoretically shown that the structures possess a non-Bragg band-gap which is invariant with a change of scale length and robust against disorder. The gap edges are determined by zero average permittivity of the branch and the backbone and zero permeability of the backbone materials, respectively. The transmission properties of the structures are investigated by changing the (average) resonator size dBand the resonator spacing dArespectively. The experimental results agree well with the theoretical predictions and numerical simulations, which demonstrate the independence of the special gap on the scaling and disorder in the structures.

Zhang, L. W.; Zhang, Y. W.; He, L.; Wang, Z. G.

2009-10-01

13

Negative Index of Refraction Portland State University  

E-print Network

Negative Index of Refraction Portland State University PH 464--Dr. Andres LaRosa Joel Rieger March not only showed that these materials have a negative index of refraction, he also showed which have a negative index of refraction, and this confused me. This was rather confusing to me

La Rosa, Andres H.

14

DOI: 10.1002/adma.200600106 Negative-Index Materials: New Frontiers  

E-print Network

. Soukoulis,* Maria Kafesaki, and Eleftherios N. Economou 1. Introduction 1.1. History of Negative (electric field), and H (magnetic field) left handed and, hence, exhibiting phase and energy velocities); hence, their alternative name, negative-in- dex materials (NIMs). The latter leads, in particular

15

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

E-print Network

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

16

Negative Index of Refraction Mary (Betsey) Mathew  

E-print Network

Negative Index of Refraction Mary (Betsey) Mathew La Rosa, Winter 2006 #12;1 ABSTRACT In recent index of refraction materials. Negative index of refraction was an idea first theorized by Victor of refraction because I was amazed that such an apparently simple discovery could have been made only so lately

La Rosa, Andres H.

17

Achromatic negative index lens with diffractive optics  

NASA Astrophysics Data System (ADS)

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

Piao, Mingxu; Cui, Qingfeng; Zhang, Bo

2015-02-01

18

Nonlinear wave propagation in negative index metamaterials  

Microsoft Academic Search

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

Nikolaos L. Tsitsas; Dimitri J. Frantzeskakis

2011-01-01

19

Structures with negative index of refraction  

DOEpatents

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

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

2011-11-08

20

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

21

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

PubMed

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

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

2014-06-24

22

Entanglement creation with negative index metamaterials  

E-print Network

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

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

2012-05-21

23

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

PubMed

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

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

2010-08-16

24

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

NASA Astrophysics Data System (ADS)

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

Garcia-Meca, Carlos

2012-02-01

25

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

PubMed

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

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

2010-05-01

26

Active negative-index metamaterial powered by an electron beam  

E-print Network

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

Shapiro, Michael

27

Resonant coupling to a dipole absorber inside a metamaterial: Anticrossing of the negative index response  

E-print Network

Resonant coupling to a dipole absorber inside a metamaterial: Anticrossing of the negative index resonance in the permeability of a fishnet metamaterial and an electric dipole material resonance Vacuum Society. DOI: 10.1116/1.3503898 I. INTRODUCTION Metamaterials, first discussed by Veselago in 1968

New Mexico, University of

28

Tunable Metallic Photonic Crystals with an Effective Negative Index of Refraction  

E-print Network

Tunable Metallic Photonic Crystals with an Effective Negative Index of Refraction Mark S. Wheeler The design of negative refractive index (NRI) metamaterials is an exciting field of research, even though metamaterials [2-4]. Although in general PCs can produce "negative refraction" with and without BW behavior

Mojahedi, Mohammad

29

Sub-picosecond optical switching with a negative index metamaterial  

SciTech Connect

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

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

2009-01-01

30

Negative refraction without negative index in metallic photonic crystals  

E-print Network

Negative refraction without negative index in metallic photonic crystals Chiyan Luo, Steven G: It is shown that certain metallic photonic crystals can enable negative refraction and subwavelength imaging negative values of and µ," Sov. Phys. Usp. 10, 509-514 (1968). 5. J. B. Pendry, "Negative refraction makes

31

A generator of far-infrared and terahertz radiation in nonlinear metamaterials exhibiting negative index of refraction  

NASA Astrophysics Data System (ADS)

Laser oscillation conditions are analyzed in nonlinear composite metamaterials exhibiting a negative index of refraction. It is demonstrated that strong quadratic and cubic nonlinearities can be simultaneously realized in such structures. Based on the described composite material, a scheme of an optically pumped parametric generator of terahertz radiation is proposed.

Zolotovskii, I. O.; Korobko, D. A.; Minvaliev, R. N.; Ostatochnikov, V. A.

2014-11-01

32

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

E-print Network

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

Sridhar, Srinivas

33

Resonant nonlinear optics of backward waves in negative-index metamaterials  

E-print Network

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

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

2008-08-14

34

Negative-Index Refraction in a Lamellar Composite with Alternating Single Negative Layers  

E-print Network

Negative-index refraction is achieved 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 famous left-handed metamaterial comprising split ring resonators and wires is interpreted as an analogy of such an ENG-MNG lamellar composite. In addition, beyond the effective medium approximation, the propagating field squeezed near the ENG/MNG interface is demonstrated to be left-handed surface waves with backward phase velocity.

Z. G. Dong; S. N. Zhu; H. Liu

2005-08-17

35

Materials in design  

E-print Network

1970 Major Subject: Mechanical Engineering ABSTRACT Materials in Design Alfredo F. Perata Directed by: Dr. H. Richard Thornton The selection of the right material is one of the first and important steps in design. Because of this, a thoughtful.... The processing behavior plays a role of great importance in the selection of the material since for some products condi- tions . of good weldability, hardenability, workability or machinability are required. The design engineer must understand the properties...

Perata, Alfredo Ferando

1970-01-01

36

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. PMID:24129667

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

2013-01-01

37

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

38

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

NASA Astrophysics Data System (ADS)

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

Bethune-Waddell, Max; Chau, Kenneth J.

2012-03-01

39

Tunable split-ring resonators for nonlinear negative-index metamaterials  

E-print Network

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

40

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

E-print Network

Intra-connected three-dimensionally isotropic bulk negative index photonic metamaterial Durdu Ã? negative index metamaterials (NIMs) are highly desired, particularly for the realization of ultra of three-dimensionally (3D) isotropic bulk optical metamaterials, but only at the expense of an additional

41

Design a Sculpting Material  

ERIC Educational Resources Information Center

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

Roman, Harry T.

2011-01-01

42

Experimental Verification of a Negative Index of Refraction  

Microsoft Academic Search

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

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

2001-01-01

43

Tunable optical negative-index metamaterials employing anisotropic liquid crystals  

E-print Network

to the applied electric field or the Kerr effect where the refractive index change is proportional to the square possess the Kerr effect that allows similar index tuning at a similar voltage require- ment. Perhaps by tuning the director orientation of anisotropic LCs or by using temperature-dependent LCs. The design

Shalaev, Vladimir M.

44

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

E-print Network

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

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

2007-08-13

45

Ultrafast nonlinear optical spectroscopy of a dual-band negative index metamaterial  

E-print Network

Ultrafast nonlinear optical spectroscopy of a dual-band negative index metamaterial all of a fishnet structure- metamaterial all-optical switching device that exhibits two near-infrared negative into separately engineering the switching time and switching ratio of such a fishnet structure metamaterial all

New Mexico, University of

46

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

47

Material-based design computation  

E-print Network

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

Oxman, Neri

2010-01-01

48

Bi-anisotropy of multiple-layer fishnet negative-index metamaterials due to angled sidewalls.  

PubMed

Simulation results of near infrared (100- to 200-THz) fishnet-structure negative-index metamaterials (NIMs) with single and multiple functional layers exhibit bi-anisotropy - inhomogeneous asymmetry - due to the presence of a sidewall-angle. The influence of sidewall-angle resulting from realistic fabrication processes is investigated through the retrieved effective parameters by both a three-dimensional finite-difference time-domain (FDTD) method and a rigorous coupled wave analysis (RCWA). PMID:19365507

Ku, Zahyun; Zhang, Jingyu; Brueck, S R J

2009-04-13

49

Propagation of Gaussian beams in negative-index metamaterials with cubic nonlinearity  

Microsoft Academic Search

Propagation of Gaussian beams in the negative-index metamaterials (NIMs) with cubic nonlinearities is investigated, both theoretically and numerically. The role of the status of the incident Gaussian beam, which is scaled by a converging parameter in this paper, in beam self-focusing and self-defocusing in NIMs is specially identified. The expressions for beam self-focusing and self-defocusing for different converging parameter cases,

Yonghua Hu; Shuangchun Wen; Youwen Wang; Dianyuan Fan

2008-01-01

50

SHORT PROGRAMS Materials By Design  

E-print Network

techniques including 3D printing, self-assembly, microfluidics and other technologies. We will distribute and analyze material samples designed based on multiscale simulations and manufactured using 3D printing

Entekhabi, Dara

51

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

PubMed

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

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

2014-05-15

52

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

E-print Network

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

A. K. Popov; Vladimir M. Shalaev

2006-01-10

53

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

54

Composite materials: Testing and design  

NASA Technical Reports Server (NTRS)

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

Whitcomb, John D. (editor)

1988-01-01

55

Advanced Aerospace Materials by Design  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

56

Principles of Inorganic Materials Design  

NASA Astrophysics Data System (ADS)

A unique interdisciplinary approach to inorganic materials design Textbooks intended for the training of chemists in the inorganic materials field often omit many relevant topics. With its interdisciplinary approach, this book fills that gap by presenting concepts from chemistry, physics, materials science, metallurgy, and ceramics in a unified treatment targeted towards the chemistry audience. Semiconductors, metal alloys and intermetallics, as well as ceramic substances are covered. Accordingly, the book should also be useful to students and working professionals in a variety of other disciplines. This book discusses a number of topics that are pertinent to the design of new inorganic materials but are typically not covered in standard solid-state chemistry books. The authors start with an introduction to structure at the mesoscopic level and progress to smaller-length scales. Next, detailed consideration is given to both phenomenological and atomistic-level descriptions of transport properties, the metal-nonmetal transition, magnetic and dielectric properties, optical properties, and mechanical properties. Finally, the authors present introductions to phase equilibria, synthesis, and nanomaterials. Other features include: Worked examples demonstrating concepts unfamiliar to the chemist Extensive references to related literature, leading readers to more in-depth coverage of particular topics Biographies introducing the reader to great contributors to the field of inorganic materials science in the twentieth century With their interdisciplinary approach, the authors have set the groundwork for communication and understanding among professionals in varied disciplines who are involved with inorganic materials engineering. Armed with this publication, students and researchers in inorganic and physical chemistry, physics, materials science, and engineering will be better equipped to face today's complex design challenges. This textbook is appropriate for senior-level undergraduate and graduate course work.

Lalena, John N.; Cleary, David

2005-04-01

57

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

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

58

Valvetrain system design and materials  

SciTech Connect

Over the past twenty years, the valvetrain for the internal combustion engine has seen significant changes. Market and regulatory demands faced by the engine manufacturers have been the driving forces of this evolution. While these demands will continue in the future, so will the development of valvetrain systems and components. As in the past, the advances to be made will depend on the ingenuity and foresight of the many valvetrain system designers and engineers as well as the suppliers of valvetrain component designs and materials. The proceedings of this conference will provide a historical perspective that will lay the foundation of where valvetrain systems and components will be heading in the future from both aspects of design and materials. Experts from the valvetrain industry have been called upon to share their insight and foresight on where we`ve been and where we are going. It is hoped that this background and open forum will provide additional insight into what is an important topic - taking the valvetrain for the internal combustion engine into the next century. Separate abstracts have been indexed into the database for contributions to this proceedings.

Bolton, H.A.; Larson, J.M. [eds.

1997-12-31

59

Propagation of Gaussian beams in negative-index metamaterials with cubic nonlinearity  

NASA Astrophysics Data System (ADS)

Propagation of Gaussian beams in the negative-index metamaterials (NIMs) with cubic nonlinearities is investigated, both theoretically and numerically. The role of the status of the incident Gaussian beam, which is scaled by a converging parameter in this paper, in beam self-focusing and self-defocusing in NIMs is specially identified. The expressions for beam self-focusing and self-defocusing for different converging parameter cases, and the dependence of the critical power and the focus location of self-focusing in NIMs on the converging parameter are obtained. It is found that it is the divergent rather than convergent incident beams which are self-focused more quickly in NIMs with defocusing nonlinearities, in sharp contrast with the propagation property of Gaussian beams in conventional Kerr media, in which beam self-focusing only occurs in the media with focusing nonlinearities and a convergent incident beam self-focuses more quickly than a divergent one. By adjusting the converging parameter of incident Gaussian beam or the controllable magnetic permeability of NIM, or both, one can manipulate the beam self-focusing in NIMs at will.

Hu, Yonghua; Wen, Shuangchun; Wang, Youwen; Fan, Dianyuan

2008-05-01

60

Material and processes selection in conceptual design  

E-print Network

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

Krishnakumar, Karthikeyan

2005-02-17

61

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

E-print Network

Refraction of electromagnetic energy for wave packets incident on a negative-index medium is always February 2004 We analyze refraction of electromagnetic wave packets on passing from an isotropic positive to an isotropic negative-refractive-index medium. We definitively show that in all cases the energy is always

Sridhar, Srinivas

62

Translating materials design to the clinic  

NASA Astrophysics Data System (ADS)

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

Hubbell, Jeffrey A.; Langer, Robert

2013-11-01

63

Computational methodologies for designing materials  

Microsoft Academic Search

It would be fair to say that in the past few decades, theory and computer modeling have played a major role in elucidating the microscopic factors that dictate the properties of functional novel materials. Together with advances in experimental techniques, theoretical methods are becoming increasingly capable of predicting properties of materials at different length scales, thereby bringing in sight the

Talat S Rahman

2009-01-01

64

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

65

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

66

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

67

Design and Manufacture of Energy Absorbing Materials  

ScienceCinema

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

Duoss, Eric

2014-05-30

68

Design and Manufacture of Energy Absorbing Materials  

SciTech Connect

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

Duoss, Eric

2014-05-28

69

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

E-print Network

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

Rogers, John A.

70

Mimicry of natural material designs and processes  

NASA Astrophysics Data System (ADS)

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

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

1995-06-01

71

Spaces of electromagnetic and mechanical constitutive parameters for dissipative media with either positive or negative index  

NASA Astrophysics Data System (ADS)

Propagation of electromagnetic and acoustic plane waves in dissipative isotropic homogeneous media is described in terms of the Poynting vector and of the complex-valued wave vector. The negative sign of the refractive index, which is explained by the presence of backward bulk waves, is then directly related to the phase angle of the complex-valued wavenumber. Attention is focused on an alternative description dealing with the complex-valued dynamic material parameters: the relative permittivity ? and the relative permeability ? for the electromagnetic wave motion, and the bulk modulus ? and the mass density ? for the acoustic wave motion. The 2D spaces of material parameters (?,?) and (?,?) are found to be split into regions characterized by their abilities both to induce wave attenuation and to exhibit opposite directions between the energy flow and the direction of the plane wave propagation. Finally, the relevance of such representations is illustrated by superimposing experimentally retrieved and simulated constitutive parameters of media supporting both forward and backward wave motions.

Dubois, J.; Aristégui, C.; Poncelet, O.

2014-01-01

72

Concurrent design of hierarchical materials and structures  

Microsoft Academic Search

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

D. L. McDowell; G. B. Olson

2008-01-01

73

Concurrent design of hierarchical materials and structures  

Microsoft Academic Search

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

D. L. McDowell; G. B. Olson

74

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

E-print Network

Numerical simulations of negative-index refraction in wedge-shaped metamaterials Z. G. Dong, S. N to evalu- ate 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

Cao, Wenwu

75

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

76

Materials design principles of ancient fish armour.  

PubMed

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

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

2008-09-01

77

Syllabus ENMA 470 -Materials Selection for Engineering Design  

E-print Network

Syllabus ENMA 470 - Materials Selection for Engineering Design and applications, and teaching you the methodology of materials selection in engineering Description: Increasing your knowledge about materials classes, properties, limitations

Rubloff, Gary W.

78

Design concepts for pressurized lunar shelters utilizing indigenous materials  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

79

Tools for Material Design and Selection  

NASA Astrophysics Data System (ADS)

The present thesis focuses on applications of numerical methods to create tools for material characterization, design and selection. The tools generated in this work incorporate a variety of programming concepts, from digital image analysis, geometry, optimization, and parallel programming to data-mining, databases and web design. The first portion of the thesis focuses on methods for characterizing clustering in bimodal 5083 Aluminum alloys created by cryomilling and powder metallurgy. The bimodal samples analyzed in the present work contain a mixture of a coarse grain phase, with a grain size on the order of several microns, and an ultra-fine grain phase, with a grain size on the order of 200 nm. The mixing of the two phases is not homogeneous and clustering is observed. To investigate clustering in these bimodal materials, various microstructures were created experimentally by conventional cryomilling, Hot Isostatic Pressing (HIP), Extrusion, Dual-Mode Dynamic Forging (DMDF) and a new 'Gradient' cryomilling process. Two techniques for quantitative clustering analysis are presented, formulated and implemented. The first technique, the Area Disorder function, provides a metric of the quality of coarse grain dispersion in an ultra-fine grain matrix and the second technique, the Two-Point Correlation function, provides a metric of long and short range spatial arrangements of the two phases, as well as an indication of the mean feature size in any direction. The two techniques are implemented on digital images created by Scanning Electron Microscopy (SEM) and Electron Backscatter Detection (EBSD) of the microstructures. To investigate structure--property relationships through modeling and simulation, strategies for generating synthetic microstructures are discussed and a computer program that generates randomized microstructures with desired configurations of clustering described by the Area Disorder Function is formulated and presented. In the computer program, two-dimensional microstructures are generated by Random Sequential Adsorption (RSA) of voxelized ellipses representing the coarse grain phase. A simulated annealing algorithm is used to geometrically optimize the placement of the ellipses in the model to achieve varying user-defined configurations of spatial arrangement of the coarse grains. During the simulated annealing process, the ellipses are allowed to overlap up to a specified threshold, allowing triple junctions to form in the model. Once the simulated annealing process is complete, the remaining space is populated by smaller ellipses representing the ultra-fine grain phase. Uniform random orientations are assigned to the grains. The program generates text files that can be imported in to Crystal Plasticity Finite Element Analysis Software for stress analysis. Finally, numerical methods and programming are applied to current issues in green engineering and hazard assessment. To understand hazards associated with materials and select safer alternatives, engineers and designers need access to up-to-date hazard information. However, hazard information comes from many disparate sources and aggregating, interpreting and taking action on the wealth of data is not trivial. In light of these challenges, a Framework for Automated Hazard Assessment based on the GreenScreen list translator is presented. The framework consists of a computer program that automatically extracts data from the GHS-Japan hazard database, loads the data into a machine-readable JSON format, transforms the JSON document in to a GreenScreen JSON document using the GreenScreen List Translator v1.2 and performs GreenScreen Benchmark scoring on the material. The GreenScreen JSON documents are then uploaded to a document storage system to allow human operators to search for, modify or add additional hazard information via a web interface.

Wehage, Kristopher

80

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

ERIC Educational Resources Information Center

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

Altman, Reuben; And Others

81

Materials design for perovskite SOFC cathodes  

Microsoft Academic Search

\\u000a Abstract  This article focuses on perovskite materials for application as cathode material in solid oxide fuel cells. In order to develop\\u000a new promising materials it is helpful to classify already known perovskite materials according to their properties and to\\u000a identify certain tendencies. Thereby, composition-dependent structural data and materials properties are considered. Structural\\u000a data under consideration are the Goldschmidt tolerance factor, which

Jörg Richter; Peter Holtappels; Thomas Graule; Tetsuro Nakamura; Ludwig J. Gauckler

2009-01-01

82

An educational program on structural design with brittle /ceramic/ materials  

NASA Technical Reports Server (NTRS)

The organization of a proposed ceramic structural materials program is described, and a suggested course sequence for college-level and graduate-level courses is presented. The course work on ceramics and brittle fracture are intended to lead to a brittle material design project and a brittle material design problem. Criteria for the selection of appropriate projects/problems are considered.

Mueller, J. I.

1978-01-01

83

A Variable Fidelity Model Management Framework for Designing Multiphase Materials  

Microsoft Academic Search

Research applications involving design tool development for multi phase material design are at an early stage of development. The computational requirements of advanced nu- merical tools for simulating material behavior such as the finite element method (FEM) and the molecular dynamics (MD) method can prohibit direct integration of these tools in a design optimization procedure where multiple iterations are required.

John E. Renaud; Vikas Tomar

2008-01-01

84

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

85

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

86

Efficient material design for diesel particulate filters  

Microsoft Academic Search

This paper will give an overview about the filter development for diesel particulate emission control in automotive applications.\\u000a The material development for passenger car diesel particulate filters led to new materials like silicon carbide while for\\u000a heavy duty applications still Cordierite plays a major role. But in the future other materials might also be used for passenger\\u000a cars. This paper

A. Schaefer-Sindlinger; I. Lappas; C. D. Vogt; T. Ito; H. Kurachi; M. Makino; A. Takahashi

2007-01-01

87

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

Code of Federal Regulations, 2011 CFR

... MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Main Propulsion Machinery § 58.05-1 Material, design and construction...design, construction, workmanship, and arrangement of main propulsion machinery and of each auxiliary, directly...

2011-10-01

88

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

Code of Federal Regulations, 2013 CFR

... MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Main Propulsion Machinery § 58.05-1 Material, design and construction...design, construction, workmanship, and arrangement of main propulsion machinery and of each auxiliary, directly...

2013-10-01

89

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

Code of Federal Regulations, 2012 CFR

... MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Main Propulsion Machinery § 58.05-1 Material, design and construction...design, construction, workmanship, and arrangement of main propulsion machinery and of each auxiliary, directly...

2012-10-01

90

Design and analysis of novel photocatalytic materials  

NASA Astrophysics Data System (ADS)

The development of sustainable sources of energy to decrease our dependence on non-renewable fossil fuels and the reduction of emissions causing global warming are important technological challenges of the 21st century. Production of solar fuels by photocatalysis is one potential route to reduce the impact of those problems. The most widely applied photocatalyst is TiO2 because it is stable, non-toxic and inexpensive. Still, it cannot utilize the solar spectrum efficiently as its band gap is 3.2 eV thus able to absorb only 3% of sun light. This thesis therefore explores multiple avenues towards improving the light absorption capability of semiconductor materials without loss in activity. To achieve this objective, the valence band hybridization method of band gap reduction was utilized. This technique is based on introducing new orbitals at the top of valence band of the semiconductor that can then hybridize with existing orbitals. The hybridization then raises the maximum of the valence band thereby reducing the band gap. This technique has the added advantage of increasing the mobility of oxidizing holes in the now dispersed valence band. In practice, this can be achieved by introducing N 2p or Sn 5s orbitals in the valence band of an oxide. We initially designed novel zinc gallium oxy-nitrides, with the spinel structure and band gaps in the visible region of the solar spectrum, by nitridation of a zinc gallate precursor produced by sol-gel synthesis. These spinel oxy-nitrides have band gaps of 2.5 to 2.7 eV, surface areas of 16 to 36 m 2/g, and nitrogen content less than 1.5%. They are active towards degradation of organic molecules in visible light. Density functional theory calculations show that this band gap reduction in part is associated with hybridization between the dopant N 2p states with Zn 3d orbitals at the top of the valence band. While spinel oxy-nitrides are produced under nitridation at 550°C, at higher temperatures they are consumed to form wurzitic oxy-nitrides. The wurzite materials also have band gaps less than 3 eV but their surface areas are 2 to 5 m2/g. The thesis explores in detail the changes associated with the gallium coordination as the spinel zinc gallate precursor transforms into the spinel oxy-nitride at 550°C, and further changes into the wurzite oxy-nitride at 850°C are studied through X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, neutron powder diffraction, X-ray absorption spectroscopy and other techniques. We believe that the protocol developed in this thesis opens an avenue for the synthesis of semiconductors having the spinel crystal structure and band gaps engineered to the visible region with potential applications for opto-electronic devices and photocatalytic processes. Though these spinel oxynitrides are interesting, they suffer from vacancies and low surface areas from the high temperature nitridation step. This could be overcome by synthesizing photocatalysts hydrothermally. We proceeded to explore the interactions of Sn2+ 5s orbitals with O 2p orbitals towards hybridizing the valence band. This led to the development of novel visible-light-active Sn2+ - TiO2 and SnOx -- ZnGa2O4 materials. The former catalysts are prepared from the reaction of titanium butoxide and several tin precursors at 80°C in aqueous solutions. Samples synthesized with SnCl2 have lower band gaps (red-shifted to the visible region) with respect to anatase TiO2. The catalysts are isostructural with anatase TiO2 even at the highest loadings of Sn2+. When the precursor is changed to SnCl4, rutile is the predominant phase obtained but no reduction in the band gap is observed. The experiments also indicate the presence of chlorine in the samples, also influencing the optical and catalytic properties as confirmed by comparison to materials prepared using bromide precursors. These catalysts are photocatalytically active for the degradation of organic molecules with rates higher than the standard (P25 TiO2) and also evidenced from the generation of hydroxyl radicals using visible

Boppana, Venkata Bharat Ram

91

Instructional Design for Developing Computer-Based Learning Materials.  

ERIC Educational Resources Information Center

Reviews instructional design research and theory and relates it to the design of computer-based instructional materials. Instructional design guidelines are offered to aid software developers in making design decisions on three macrolevel and four microlevel of instruction. (Author/LRW)

Wedman, John F.; Ragan, Tillman J.

1986-01-01

92

Materials 4: Design Strategies for Transformative Innovation  

NSDL National Science Digital Library

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

Vanasupa, Linda

93

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

94

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

95

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

96

Computer-Aided Design Of Sheet-Material Parts  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

97

Impact of low activation materials on fusion reactor design  

Microsoft Academic Search

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

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

1998-01-01

98

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

99

Materials Process Design and Control Laboratory Cornell University  

E-print Network

. Rhodes Hall Cornell University Ithaca, NY 14853-3801 Email: bw336@cornell.edu URL: http://mpdc.mae.cornell.eduMaterials Process Design and Control Laboratory Cornell University STOCHASTIC MULTISCALE MODELING/ #12;Materials Process Design and Control Laboratory Cornell University Outline Introduction

Zabaras, Nicholas J.

100

Materials Process Design and Control Laboratory Cornell University  

E-print Network

Cornell University Ithaca, NY 14853-3801 Email: zabaras@cornell.edu URL: http://mpdc.mae.cornell.eduMaterials Process Design and Control Laboratory Cornell University A New Approach to Solve/ Jiang Wan and Nicholas Zabaras #12;Materials Process Design and Control Laboratory Cornell University

Zabaras, Nicholas J.

101

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

102

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

103

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

104

Designing Functional Nanoscale Materials and Structures  

Microsoft Academic Search

In the presentation, I shall discuss about the recent results from our laboratory on the development of newer forms of lithography, synthesis of nanoscale particles and composites, and their applications in developing principles for sensors and actuators. The talk will also delve into the newer principles of designing chemical locomotives. Some of the resent results of nanobiotechnology from our laboratory

Arun Chattopadhyay

2008-01-01

105

Designing Training Materials for Developing Countries.  

ERIC Educational Resources Information Center

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

Rosenweig, Fred

1984-01-01

106

Designing colloidal suspensions for directed materials assembly  

SciTech Connect

Recent advances in microfluidic and direct-write assembly of colloidal suspensions open new avenues for microscale patterning of functional materials with controlled composition, geometry, and properties. In this article, we describe fundamental aspects of suspension structure, elasticity, and flow behavior for three important systems: (1) dense liquids (and glasses), (2) gels, and (3) biphasic mixtures. We also highlight examples from the current literature of colloidal architectures patterned by these emerging methods.

Conrad, Jacinta C; Ferreira, Summer R; Yoshikawa, Jun; Shepherd, Robert F; Ahn, Bok Y; Lewis, Jennifer A

2011-01-01

107

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

E-print Network

, life cycle design engineering, modular design, design for manufacturing, intelligent design Design and Materials Design The Design area is a rapidly growing research area aimed at furthering the development

Calgary, University of

108

The automated design of materials far from equilibrium  

NASA Astrophysics Data System (ADS)

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

Miskin, Marc Z.

109

Designer Materials: An Introduction to the Application of Materials Science and Technology.  

ERIC Educational Resources Information Center

Explains how middle schoolers can learn about the basic types of materials and their properties, how to measure and safely use basic tools, and how to design and construct a prototype and final project using these materials. Includes a design activity. (JOW)

Fitzgerald, Mike

2002-01-01

110

Photovoltaic module encapsulation design and materials selection, volume 1  

NASA Astrophysics Data System (ADS)

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

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

1982-06-01

111

Photovoltaic module encapsulation design and materials selection, volume 1  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

112

Designing Radiation Resistance in Materials for Fusion Energy  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

113

A COMPUTER-AIDED MATERIAL SELECTION FOR DESIGN OF AUTOMOTIVE SAFETY CRITICAL COMPONENTS WITH NOVEL MATERIALS  

Microsoft Academic Search

An expert system for material selection for design of automotive component with fibre reinforced plastic materials has been developed. The expert-system shell KEE (Knowledge Engineering Environment) provides a tool to store and process expert knowledge. The system concentrates on selecting suitable materials for automotive components, in particular for major elements of pedal box system namely the mounting bracket, the accelerator,

S. M. Sapuan

1999-01-01

114

First Principles Modeling for Research and Design of New Materials  

E-print Network

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

Ceder, Gerbrand

115

Material Surface Design to Counter Electromagnetic Interrogation of Targets  

E-print Network

Material Surface Design to Counter Electromagnetic Interrogation of Targets H.T. Banks, K. Ito, G to protect parts of an irradiated target or to focus radiation to pinpoint specific regions of the target

116

Material evaluation and selection processes to enable design for manufacture  

E-print Network

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

Abler, Craig Bennett, 1975-

2006-01-01

117

Evaluation of materials and design modifications for aircraft brakes  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

118

Synthesis and Materials Design for Heteroanion Compounds  

NASA Astrophysics Data System (ADS)

Oxynitride phosphors, SrSi2O2N2:Eu2+ were synthesized through a conventional solid state reaction between Sr2SiO4:Eu2+ precursor and Si3N4 by using NH4Cl flux, and their luminescence properties were characterized from a viewpoint of the ionic and covalent bond natures as the "heteroanion compound" containing O2- and N3- anions. The structural framework of host lattice is constructed by covalently bonded layers of SiON3 units, suggesting that the rearrangement of O2- and N3- anions effectively takes place between isolated SiO44-anions of the Sr2SiO4:Eu2+ precursor and SiN4 units of the Si3N4 raw material. Furthermore, the layered structure consisting of (Si2O2N2)n2n- polyanions as tightly connected by Si-N-Si covalent bonds depresses the lattice vibration of Sr(Eu)-O or Si-O bond, so that the temperature quenching effect is lowered to give the intense emission for LED-based illumination lamps.

Machida, K.

2011-02-01

119

Designing Radiation Resistance in Materials for Fusion Energy  

SciTech Connect

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

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

2014-01-01

120

Energy flux pattern of inverse Goos-Hanchen shift in photonic crystals with negative index of refraction  

E-print Network

The energy flux patterns of inverse Goos-Hanchen (GH) shift around the interface between air and negatively refractive photonic crystal (NRPhC) with different surface terminations is investigated. Results show that NRPhC exhibits inverse GH shift in TM and TE polarization, and the localization and pattern of energy flux differ in TM and TE polarizations and are strongly affected by surface termination. This is different to the condition of negative permittivity materials (i.e., metal), which only presents inverse GH shift in TM polarization. In the case of TE polarization, the energy flux pattern exhibits the flux of backward wave whose localization changes from the surface to inside of NRPhC with the variation of surface termination. In the case of TM polarization, the energy flux pattern is always confined within the surface of NRPhC, whereas its pattern changes from the flux of backward wave to vortices at the surface of NRPhC, which is different to the energy flux of TM polarization of metal. By properly ...

Hu, Jinbing; Chen, Jiabi; Jiang, Qiang; Wang, Yan; Zhuang, Songlin

2015-01-01

121

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.

122

Chemical aspects of the design of thermoelectric materials  

Microsoft Academic Search

The relationship between the composition, structure and properties of promising thermoelectric materials is analysed. Different classes of chemical compounds that serve the basis for the development of thermoelectrics are considered. Special attention is drawn to chemical problems associated with the design of the new-generation thermoelectric materials. The prospects for the development of this research field are demonstrated.

A. V. Shevelkov

2008-01-01

123

The high-throughput highway to computational materials design  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

124

Design Guidelines for Digital Learning Material for Food Chemistry Education.  

ERIC Educational Resources Information Center

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

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

125

Structure-based design of functional amyloid materials.  

PubMed

Amyloid fibers, once exclusively associated with disease, are acquiring utility as a class of biological nanomaterials. Here we introduce a method that utilizes the atomic structures of amyloid peptides, to design materials with versatile applications. As a model application, we designed amyloid fibers capable of capturing carbon dioxide from flue gas, to address the global problem of excess anthropogenic carbon dioxide. By measuring dynamic separation of carbon dioxide from nitrogen, we show that fibers with designed amino acid sequences double the carbon dioxide binding capacity of the previously reported fiber formed by VQIVYK from Tau protein. In a second application, we designed fibers that facilitate retroviral gene transfer. By measuring lentiviral transduction, we show that designed fibers exceed the efficiency of polybrene, a commonly used enhancer of transduction. The same procedures can be adapted to the design of countless other amyloid materials with a variety of properties and uses. PMID:25474758

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

2014-12-31

126

Optimum place of piezoelectric material in the piezoactuator design  

NASA Astrophysics Data System (ADS)

Piezoelectric actuators offer significant promise in a wide range of applications. The piezoelectric actuators considered in this work essentially consist of a flexible structure actuated by piezoceramics that must generate output displacement and force at a certain specified point of the domain and direction. The flexible structure acts as a mechanical transformer by amplifying and changing the direction of piezoceramics output displacements. The design of these piezoelectric actuators are complex and a systematic design method, such as topology optimization has been successfully applied in the latest years, with appropriate formulation of the optimization problem to obtain optimized designs. However, in these previous design formulations, piezoceramics position are usually kept fixed in the design domain and only the flexible structure is designed by distributing only some non-piezoelectric material (Aluminum, for example). This imposes a constraint in the position of piezoelectric material in the optimization problem limiting the optimality of the solution. Thus, in this work, a formulation that allows the simultaneous search for an optimal topology of a flexible structure as well as the optimal positions of the piezoceramics in the design domain, to achieve certain specified actuation movements, will be presented. This can be achieved by allowing the simultaneous distribution of non-piezoelectric and piezoelectric material in the design domain. The optimization problem is posed as the design of a flexible structure together with optimum positions of piezoelectric material that maximizes output displacements or output forces in a certain specified direction and point of the domain. The method is implemented based on the SIMP material model where fictitious densities are interpolated in each finite element, providing a continuum material distribution in the domain. Presented examples are limited to two-dimensional models, once most of the applications for such piezoelectric actuators are planar devices.

Carbonari, Ronny C.; Nishiwaki, Shinji; Silva, Emílio C. N.

2006-03-01

127

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

NASA Technical Reports Server (NTRS)

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

Inman, Daniel J.; Cudney, Harley H.

2000-01-01

128

Design Exploration of Engineered Materials, Products, and Associated Manufacturing Processes  

NASA Astrophysics Data System (ADS)

In the past few years, ICME-related research has been directed towards the study of multi-scale materials design. However, relatively little has been reported on model-based methods that are of relevance to industry for the realization of engineered materials, products, and associated industrial manufacturing processes. Computational models used in the realization of engineered materials and products are fraught with uncertainty, have different levels of fidelity, are incomplete and are even likely to be inaccurate. In light of this, we adopt a robust design strategy that facilitates the exploration of the solution space thereby providing decision support to a design engineer. In this paper, we describe a foundational construct embodied in our method for design exploration, namely, the compromise Decision Support Problem. We introduce a problem that we are using to establish the efficacy of our method. It involves the integrated design of steel and gears, traversing the chain of steel making, mill production, and evolution of the material during these processes, and linking this to the mechanical design and manufacture of the gear. We provide an overview of our method to determine the operating set points for the ladle, tundish and caster operations necessary to manufacture steel of a desired set of properties. Finally, we highlight the efficacy of our method.

Shukla, Rishabh; Kulkarni, Nagesh H.; Gautham, B. P.; Singh, Amarendra K.; Mistree, Farrokh; Allen, Janet K.; Panchal, Jitesh H.

2015-01-01

129

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

130

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

SciTech Connect

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

Stephanie Austad

2010-06-01

131

Optimal Experiment Design for Thermal Characterization of Functionally Graded Materials  

NASA Technical Reports Server (NTRS)

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

Cole, Kevin D.

2003-01-01

132

Modular design in natural and biomimetic soft materials.  

PubMed

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

Kushner, Aaron M; Guan, Zhibin

2011-09-19

133

Soft computing in design and manufacturing of advanced materials  

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

134

New test-electrode design for active material characterization  

SciTech Connect

An electrode system which permits cost-effective electrochemical investigation of active materials under one-dimensional current distribution has been developed. Experimental results prove the reliability of electrode-bed characterization under a wide variety of conditions that include electrode composition and structure, different forms of distributed current collection, isometric or isobaric material confinement, etc. The method provides fundamental data elements for cell design and optimization.

Redey, L.; Vissers, D.R.

1983-01-01

135

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

136

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

137

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

138

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

139

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

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

2014-10-01

140

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

141

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

142

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

143

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

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

2014-10-01

144

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

145

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

146

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

Code of Federal Regulations, 2011 CFR

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

2011-10-01

147

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

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

2014-10-01

148

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

Code of Federal Regulations, 2012 CFR

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

2012-10-01

149

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

Code of Federal Regulations, 2013 CFR

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

2013-10-01

150

LUTE primary mirror materials and design study report  

NASA Technical Reports Server (NTRS)

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

Ruthven, Greg

1993-01-01

151

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

PubMed

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

Chau, Kenneth J; Lezec, Henri J

2012-04-23

152

The Cam Shell: An Innovative Design With Materials and Manufacturing  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

153

Designing silk-silk protein alloy materials for biomedical applications.  

PubMed

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

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

2014-01-01

154

Advanced High Temperature Turbine Seals Materials and Designs  

Microsoft Academic Search

Advanced turbine seal materials and designs are under development to achieve higher temperature capability, extended lifetime and reliability than the state of the art technology. Cooling air consumption, inspection cycles interval and repair costs of aero engines have to be reduced. In the following, results of a program funded by the European Community under the \\

W. Smarsly; N. Zheng; C. S. Buchheim; C. Nindel; C. Silvestro; D. Sporer; M. Tuffs; K. Schreiber; C. Langlade-Bomba; Olaf Andersen; H. Goehler; N. J. Simms; Gordon M. McColvin

2005-01-01

155

Ferroelectric materials for piezoelectric actuators by optimal design  

Microsoft Academic Search

Optimization methods provide a systematic means of designing heterogeneous materials with tailored properties and microstructures focussing on a specific objective. An optimization procedure incorporating a continuum modeling is used in this work to identify the ideal orientation distribution of ferroelectrics (FEs) for application in piezoelectric actuators. Piezoelectric actuation is dictated primarily by the piezoelectric strain coefficients di?. Crystallographic orientation is

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

2011-01-01

156

Empowering Materiality: Inspiring the Design of Tangible Interactions  

E-print Network

Empowering Materiality: Inspiring the Design of Tangible Interactions Magdalena Schmid BMW AG Knorrstr. 147, Munich, Germany Magdalena.Schmid@bmw.de +49 89 382 60947 Sonja Rümelin BMW Research and Technology Hanauerstr. 46, Munich, Germany Sonja.Ruemelin@bmw.de +49 89 382 51985 Hendrik Richter University

157

Designed amyloid fibers as materials for selective carbon dioxide capture  

E-print Network

Designed amyloid fibers as materials for selective carbon dioxide capture Dan Lia,b,c,1 , Hiroyasu demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide

158

Designing ECM-mimetic materials using protein engineering.  

PubMed

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

Cai, Lei; Heilshorn, Sarah C

2014-04-01

159

CubeSat Material Limits for Design for Demise  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

160

The design and modeling of periodic materials with novel properties  

NASA Astrophysics Data System (ADS)

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

Berger, Jonathan Bernard

161

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

162

Designed amyloid fibers as materials for selective carbon dioxide capture  

PubMed Central

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

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

2014-01-01

163

Rational Design of Pathogen-Mimicking Amphiphilic Materials as Nanoadjuvants  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

164

Design of nanostructured materials from block copolymer self-assembly  

Microsoft Academic Search

We present two classes of nanostructured materials by combining the self assembly of block copolymer (BCP) with suitable small molecule chemistry, which are applicable to organic electro-optics (EO) and as etch-resistant masks for nanofabrication. The underlying principles of designing the specific interactions between BCP host and guest molecules, driving the self-assembly in bulk and thin film, and dictating domain orientation

Melvina Leolukman

2010-01-01

165

Design of nanoscaled materials based on tetraoxa[8]circulene.  

PubMed

Nanotubes and two-dimensional sheet-like compounds containing tetraoxa[8]circulene core units are theoretically predicted. The large cavities with a diameter of 6 Å in the 2D sheets could be useful for hydrogen storage. The designed compounds are predicted to adsorb strongly in the visible region and to be a promising material for nanophotonics because of their electron-donor properties (p-type semiconductors). PMID:24595458

Baryshnikov, Gleb V; Minaev, Boris F; Karaush, Nataliya N; Minaeva, Valentina A

2014-04-14

166

Textile Materials for the Design of Wearable Antennas: A Survey  

PubMed Central

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

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

2012-01-01

167

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

Code of Federal Regulations, 2010 CFR

...supervision of materials, design, and building. 401...supervision of materials, design, and building. The Commission controls the design and prescribes regulations...in a foreign country or political division of the...

2010-07-01

168

Designs and Materials for Better Coronagraph Occulting Masks  

NASA Technical Reports Server (NTRS)

New designs, and materials appropriate for such designs, are under investigation in an effort to develop coronagraph occulting masks having broad-band spectral characteristics superior to those currently employed. These designs and materials are applicable to all coronagraphs, both ground-based and spaceborne. This effort also offers potential benefits for the development of other optical masks and filters that are required (1) for precisely tailored spatial transmission profiles, (2) to be characterized by optical-density neutrality and phase neutrality (that is, to be characterized by constant optical density and constant phase over broad wavelength ranges), and/or (3) not to exhibit optical- density-dependent phase shifts. The need for this effort arises for the following reasons: Coronagraph occulting masks are required to impose, on beams of light transmitted through them, extremely precise control of amplitude and phase according to carefully designed transmission profiles. In the original application that gave rise to this effort, the concern has been to develop broad-band occulting masks for NASA s Terrestrial Planet Finder coronagraph. Until now, experimental samples of these masks have been made from high-energy-beam-sensitive (HEBS) glass, which becomes locally dark where irradiated with a high-energy electron beam, the amount of darkening depending on the electron-beam energy and dose. Precise mask profiles have been written on HEBS glass blanks by use of electron beams, and the masks have performed satisfactorily in monochromatic light. However, the optical-density and phase profiles of the HEBS masks vary significantly with wavelength; consequently, the HEBS masks perform unsatisfactorily in broad-band light. The key properties of materials to be used in coronagraph occulting masks are their extinction coefficients, their indices of refraction, and the variations of these parameters with wavelength. The effort thus far has included theoretical predictions of performances of masks that would be made from alternative materials chosen because the wavelength dependences of their extinction coefficients and their indices of refraction are such that that the optical-density and phase profiles of masks made from these materials can be expected to vary much less with wavelength than do those of masks made from HEBS glass. The alternative materials considered thus far include some elemental metals such as Pt and Ni, metal alloys such as Inconel, metal nitrides such as TiN, and dielectrics such as SiO2. A mask as now envisioned would include thin metal and dielectric films having stepped or smoothly varying thicknesses (see figure). The thicknesses would be chosen, taking account of the indices of refraction and extinction coefficients, to obtain an acceptably close approximation of the desired spatial transmittance profile with a flat phase profile

Balasubramanian, Kunjithapatham

2010-01-01

169

Interfacial properties and design of functional energy materials.  

PubMed

Conspectus The vital importance of energy to society continues to demand a relentless pursuit of energy responsive materials that can bridge fundamental chemical structures at the molecular level and achieve improved functionality and performance. This demand can potentially be realized by harnessing the power of self-assembly, a spontaneous process where molecules or much larger entities form ordered aggregates as a consequence of predominately noncovalent (weak) interactions. Self-assembly is the key to bottom-up design of molecular devices, because the nearly atomic-level control is very difficult to realize in a top-down, for example, lithographic, approach. However, while function in simple systems such as single crystals can often be evaluated a priori, predicting the function of the great variety of self-assembled molecular architectures is complicated by the lack of understanding and control over nanoscale interactions, mesoscale architectures, and macroscale order. To establish a foundation toward delivering practical solutions, it is critical to develop an understanding of the chemical and physical mechanisms responsible for the self-assembly of molecular and hybrid materials on various support substrates. Typical molecular self-assembly involves noncovalent intermolecular and substrate-molecule interactions. These interactions remain poorly understood, due to the combination of many-body interactions compounded by local or collective influences from the substrate atomic lattice and electronic structure. Progress toward unraveling the underlying physicochemical processes that control the structure and macroscopic physical, chemical, mechanical, electrical, and transport properties of materials increasingly requires tight integration of theory, modeling, and simulation with precision synthesis, advanced experimental characterization, and device measurements. Theory, modeling, and simulation can accelerate the process of materials understanding and design by providing atomic level understanding of the underlying physicochemical phenomena (illuminating connections between experiments). It can also provide the ability to explore new materials and conditions before they are realized in the laboratory. With tight integration and feedback with experiment, it becomes feasible to identify promising materials or processes for targeted energy applications. In this Account, we highlight recent advances and success in using an integrated approach based on electronic structure simulations and scanning probe microscopy techniques to study and design functional materials formed from the self-assembly of molecules into supramolecular or polymeric architectures on substrates. PMID:24963787

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

2014-11-18

170

Materials, design and processing of air encapsulated MEMS packaging  

NASA Astrophysics Data System (ADS)

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

Fritz, Nathan T.

171

Design Of An Optical Linewidth Standard Reference Material For Wafers  

NASA Astrophysics Data System (ADS)

Optical linewidth measurements on patterned wafers are complicated by the wide variety of materials and correspondingly wide variation in optical parameters, complex refractive index and thickness, used in the manufacture of integrated circuits. It has been shown that in addition to linewidth, two key parameters, the normalized local reflectance R and the optical phase difference ? at the line edge, determine the characteristics of the optical image and, therefore, affect the accuracy and precision of linewidth measurements. Both of these parameters, R and ?, are dependent upon the illuminating wavelength or spectral bandpass and the coherence parameter of the optical system. To achieve the measurement precision and accuracy required for VLSI dimensions (e.g., 10% tolerance for 1-?m linewidths), it is necessary to control coherence, spectral bandpass, and image integrity as well as to achieve reproducible edge detection and focus criteria. When a system can be operated without further operator intervention despite changes in the materials being mea-sured, it is possible to calibrate the linewidth measurement system using a standard fabri-cated from only a few materials representing a range of image characteristics. The desirable characteristics of such a standard are discussed with respect to durability, edge definition, and equivalence of the image characteristics to materials used in the manufacture of ICs. A prototype design consisting of combinations of SiO2 and chromium layers on a silicon substrate is presented.

Nyyssonen, Diana

1982-10-01

172

Computational materials design for bulk heterojunction solar cells  

NASA Astrophysics Data System (ADS)

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

Lin, Xi; Shin, Yongwoo

2013-03-01

173

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

174

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

2013-09-15

175

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. PMID:23525884

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

2013-01-01

176

Topology design and optimization of nonlinear periodic materials  

NASA Astrophysics Data System (ADS)

This paper explores optimal topologies yielding large band gap shifts in one- and two-dimensional nonlinear periodic materials. The presence of a nonlinearity in a periodic material system results in amplitude-dependent dispersion behavior, leading to novel wave-based devices such as tunable filters, resonators, and waveguides. The performance of these devices over a broad frequency range requires large, tunable band gaps, motivating the present study. Consideration of a one-dimensional bilayer system composed of alternating linear and nonlinear layers shows that optimal designs consist of thin, compliant nonlinear layers. This is at first surprising considering the source of the shift originates from only the nonlinear layer; however, thin layers lead to localized stresses that activate the nonlinear character of the system. This trend persists in two-dimensional materials where optimization studies are performed on plane-stress models discretized using bilinear Lagrange elements. A fast algorithm is introduced for computing the dispersion shifts, enabling efficient parametric analyses of two-dimensional inclusion systems. Analogous to the one-dimensional system, it is shown that thin ligaments of nonlinear material lead to large dispersion shifts and group velocity variations. Optimal topologies of the two-dimensional system are also explored using genetic algorithms aimed at producing large increases in complete band gap width and shift, or group velocity variation, without presupposing the topology. The optimal topologies that result resemble the two-dimensional inclusion systems, but with small corner features that tend to enhance the production of dispersion shift further. Finally, the study concludes with a discussion on Bloch wave modes and their important role in the production of amplitude-dependent dispersion behavior. The results of the study provide insight and guidance on selecting topologies and materials which can yield large amplitude-dependent band gap shifts and group velocity variations, thus enabling sensitive nonlinear devices.

Manktelow, Kevin L.; Leamy, Michael J.; Ruzzene, Massimo

2013-12-01

177

From molecular design and materials construction to organic nanophotonic devices.  

PubMed

Conspectus Nanophotonics has recently received broad research interest, since it may provide an alternative opportunity to overcome the fundamental limitations in electronic circuits. Diverse optical materials down to the wavelength scale are required to develop nanophotonic devices, including functional components for light emission, transmission, and detection. During the past decade, the chemists have made their own contributions to this interdisciplinary field, especially from the controlled fabrication of nanophotonic molecules and materials. In this context, organic micro- or nanocrystals have been developed as a very promising kind of building block in the construction of novel units for integrated nanophotonics, mainly due to the great versatility in organic molecular structures and their flexibility for the subsequent processing. Following the pioneering works on organic nanolasers and optical waveguides, the organic nanophotonic materials and devices have attracted increasing interest and developed rapidly during the past few years. In this Account, we review our research on the photonic performance of molecular micro- or nanostructures and the latest breakthroughs toward organic nanophotonic devices. Overall, the versatile features of organic materials are highlighted, because they brings tunable optical properties based on molecular design, size-dependent light confinement in low-dimensional structures, and various device geometries for nanophotonic integration. The molecular diversity enables abundant optical transitions in conjugated ?-electron systems, and thus brings specific photonic functions into molecular aggregates. The morphology of these micro- or nanostructures can be further controlled based on the weak intermolecular interactions during molecular assembly process, making the aggregates show photon confinement or light guiding properties as nanophotonic materials. By adoption of some active processes in the composite of two or more materials, such as energy transfer, charge separation, and exciton-plasmon coupling, a series of novel nanophotonic devices could be achieved for light signal manipulation. First, we provide an overview of the research evolution of organic nanophotonics, which arises from attempts to explore the photonic potentials of low-dimensional structures assembled from organic molecules. Then, recent advances in this field are described from the viewpoints of molecules, materials, and devices. Many kinds of optofunctional molecules are designed and synthesized according to the demands in high luminescence yield, nonlinear optical response, and other optical properties. Due to the weak interactions between these molecules, numerous micro- or nanostructures could be prepared via self-assembly or vapor-deposition, bringing the capabilities of light transport and confinement at the wavelength scale. The above advantages provide great possibilities in the fabrication of organic nanophotonic devices, by rationally combining these functional components to manipulate light signals. Finally, we present our views on the current challenges as well as the future development of organic nanophotonic materials and devices. This Account gives a comprehensive understanding of organic nanophotonics, including the design and fabrication of organic micro- or nanocrystals with specific photonic properties and their promising applications in functional nanophotonic components and integrated circuits. PMID:25343682

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

2014-12-16

178

Materials Design for Joinable, High Performance Aluminum Alloys  

NASA Astrophysics Data System (ADS)

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

Glamm, Ryan James

179

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

180

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

181

Optical metamaterials: Design, simulation and feedback from experimental characterization  

NASA Astrophysics Data System (ADS)

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

Chettiar, Uday Krishnaswamy

182

Failure modes and materials design for biomechanical layer structures  

NASA Astrophysics Data System (ADS)

Ceramic materials are finding increasing usage in the area of biomechanical replacements---dental crowns, hip and bone implants, etc.---where strength, wear resistance, biocompatibility, chemical durability and even aesthetics are critical issues. Aesthetic ceramic crowns have been widely used in dentistry to replace damaged or missing teeth. However, the failure rates of ceramic crowns, especially all-ceramic crowns, can be 1%˜6% per year, which is not satisfactory to patients. The materials limitations and underlying fracture mechanisms of these prostheses are not well understood. In this thesis, fundamental fracture and damage mechanisms in model dental bilayer and trilayer structures are studied. Principle failure modes are identified from in situ experimentation and confirmed by fracture mechanics analysis. In bilayer structures of ceramic/polycarbonate (representative of ceramic crown/dentin structure), three major damage sources are identified: (i) top-surface cone cracks or (ii) quasiplasticity, dominating in thick ceramic bilayers; (iii) bottom-surface radial cracks, dominating in thin ceramic bilayers. Critical load P for each damage mode are measured in six dental ceramics: Y-TZP zirconia, glass-infiltrated zirconia and alumina (InCeram), glass-ceramic (Empress II), Porcelain (Mark II and Empress) bonded to polymer substrates, as a function of ceramic thickness d in the range of 100 mum to 10 mm. P is found independent of d for mode (i) and (ii), but has a d 2 relations for mode (iii)---bottom surface radial cracking. In trilayer structures of glass/core-ceramic/polycarbonate (representing veneer porcelain/core/dentin structures), three inner fracture origins are identified: radial cracks from the bottom surface in the (i) first and (ii) second layers; and (iii) quasiplasticity in core-ceramic layer. The role of relative veneer/core thickness, d1/d 2 and materials properties is investigated for three core materials with different modulus (114--270GPa) and strength (400--1400MPa): Y-TZP zirconia, InCeram alumina and Empress II glass-ceramic. Explicit relations for the critical loads P to produce these different damage modes in bilayer and trilayer structures are developed in terms of basic material properties (modulus E, strength, hardness H and toughness T) and geometrical variables (thickness d and contact sphere radius r). These experimentally validated relations are used to design of optimal material combinations for improved fracture resistance and to predict mechanical performance of current dental materials.

Deng, Yan

183

Harvesting bioenergy with rationally designed complex functional materials  

NASA Astrophysics Data System (ADS)

A key challenge in renewable energy is to capture, convert and store solar power with earth-abundant materials and environmentally benign technologies. The goal of this thesis is to develop rationally designed complex functional materials for bio-renewable energy applications. On one hand, photoconversion membrane proteins (MPs) are nature's nanoengineering feats for renewable energy management. Harnessing their functions in synthetic systems could help understand, predict, and ultimately control matter and energy at the nanoscale. This is particularly enticing in the post-genome era as recombinant or cell-free expression of many MPs with high yields becomes possible. However, the labile nature of lipid bilayers renders them unsuitable for use in a broad range of engineered systems. A knowledge gap exists about how to design robust synthetic nanomembranes as lipid-bilayer-mimics to support MP functions and how to direct hierarchical MP reconstitution into those membranes to form 2-D or 3-D ordered proteomembrane arrays. Our studies on proteorhodopsin (PR) and bacterial reaction center (BRC), the two light-harvesting MPs, reveal that a charge-interaction-directed reconstitution (CIDR) mechanism induces spontaneous reconstitution of detergent-solubilized MPs into various amphiphilic block copolymer membranes, many of which have far superior stability than lipid bilayers. Our preliminary data also suggest MPs are not enslaved by the biological membranes they derive from; rather, the chemically nonspecific material properties of MP-supporting membranes may act as allosteric regulators. Versatile chemical designs are possible to modulate the conformational energetics of MPs, hence their transport performance in synthetic systems. On the other hand, microalgae are widely regarded as a sustainable feedstock for biofuel production. Microalgae-derived biofuels have not been commercialized yet because current technologies for microalgae dewatering add a huge cost to the final product, and present a major bottleneck. We propose to solve the microalgae dewatering problem in the context of controlling colloidal stability, where inter-algal potential is tuned via surface engineering of novel coagulation agents. We report here a nanoparticle-pinched polymer brush design that combines two known colloidal destabilization agents (e.g., nanoparticle and polymer) into one system, and allows the use of an external field (e.g., magnetic force) to not only modulate inter-algae pair potentials, but also facilitate retrieval of the coagulation agents to be reused after algal oil extraction. We will discuss our extensive data on the preparation of well-defined nanoparticle-pinched polymer brushes, their structure-dependent coagulation performance on both fresh water and marine microalgae species, and their re-suability for continuous cycles of microalgae farming and harvesting.

Kuang, Liangju

184

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

185

Optimal Design of Honeycomb Material Used to Mitigate Head Impact  

PubMed Central

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

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

2013-01-01

186

Materials for Consideration in Standardized Canister Design Activities  

SciTech Connect

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

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

2014-10-01

187

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

188

Design of Functional Materials with Hydrogen-Bonded Host Frameworks  

NASA Astrophysics Data System (ADS)

The properties of molecular crystals are governed by the attributes of their molecular constituents and their solid-state arrangements, making control of crystal packing paramount when designing new materials with targeted functions. One effective strategy involves the use of robust host frameworks that encapsulate functional guests in molecular-scale cavities with tailored shapes, sizes, and chemical environments that enable systematic regulation of solid state properties. This approach promises to simplify the synthesis of molecular materials by decoupling the design of structure, provided by the host framework, from function, introduced by the guests. This thesis has reported a series of crystalline, structurally robust hosts based on guanidinium cations (G = (C(NH2) 3 +) and the sulfonate moieties of organodisulfonate anions (DS; S = -O3S-R-SO3 -). The host framework is based on layers of 2-D GS sheet, which are interconnected by the organic residues (pillars) of the disulfonates, thereby producing a lamellar architecture with inclusion cavities, occupied by guest molecules, between the sheets. Notably, the GDS inclusion compounds exhibit numerous architectures such as bilayer, simple brick, and zigzag brick -- each endowed with uniquely sized and shaped cavities, suggesting that the aggregation motifs of the included guests can be controlled within the host lattice. Furthermore, the selectivity toward different architectures is governed by the relative size of the pillars and guests, allowing the construction of a "structural phase diagram" which can be used to predict the solid-state architecture of untested host-guest combination. Consequently, a variety of functional molecules have been included in order to exploit these features. Chapter 3 reports the inclusion of polyconjugated molecules within the GDS hosts, generating various guest aggregation motifs -- edge-to-edge to face-to-edge to end-to-end. The effects of the various host and/or guest aggregation motifs on the optical properties of the confined guests are manifested in the bathochromic shifts in the absorption and emission spectra relative to those in dilute solution. The shifts in the absorption bands were corroborated by ab initio computations (using TDDFT at the PBE0/6-311G(d,p) level) based on the structures of the host-guest aggregates observed in the crystalline state. Chapter 4 describes the inclusion of several coumarin-based laser dyes. GDS hosts with the bilayer architectures include the dye as monomers, whereas those with the brick architectures include the dye as dimers. The ability to tune the emission wavelength through choice of dye and adjustment of framework architectures enables the design of a new class of efficient laser dye crystals. Furthermore, the excited state lifetime of some of the confined dyes in the host matrix were extended by up to ten times longer than those in dilute solutions -- an important characteristic for producing efficient lasing crystals. Chapter 5 details the inclusion of a variety of TEMPO-based radicals, whose molecular arrangement can be controlled depending on the host framework architecture. GDS hosts with the simple brick architecture generate 1-D channels which organize the radical guests into a two-leg ladder, whereas GDS hosts with the zigzag brick architecture distribute the radical guests into a 2-D square-planar lattice. Although magnetic susceptibility measurements indicate long-range antiferromagnetic ordering in these materials, the ability to form 1-D or 2-D spin systems in these frameworks may allow the design of low-dimensional magnets. Collectively, this thesis demonstrates the ability of the GDS hosts to regulate the solid-state structure of functional guest molecules, which suggests a route to the design and synthesis of materials with future applications in areas as diverse as optoelectronics, magnetics, and confined reactions.

Soegiarto, Airon Cosanova

189

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

E-print Network

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

Gonzalez Uribe, Carlos David

2014-01-01

190

Design of nanostructured materials from block copolymer self-assembly  

NASA Astrophysics Data System (ADS)

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

Leolukman, Melvina

191

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...of the Marine Protection, Research and Sanctuaries Act of...

2013-06-24

192

Institute for Critical Technology and Applied Science Seminar Series Materials & Design  

E-print Network

faculty in the Department of Materials Science and Engineering. In 1990, Dr. Balasubramanian returned; advanced materials and product creation for automotive, energy, processengineeringInstitute for Critical Technology and Applied Science Seminar Series Materials & Design

Beex, A. A. "Louis"

193

Controlling Emission Zone in Blue OLEDs by Material Design  

NASA Astrophysics Data System (ADS)

The blue component is one of the remaining challenges for the organic light emitting devices (OLED) based solid-state lighting technology. OLEDs have the potential to generate solid state white lighting with 50% power conversion efficiency. However realizing this potential will require optimization of not only blue emitter dopants but also host matrices. Charge balance is a key factor in achieving high quantum efficiency and low operating voltage in OLED devices. In this work, we studied the effect of the chemical structure of the phosphine oxide-based hosts and electron transport materials on the location of the emission zone. We observed that a strong domination of one carrier within the host results in highly localized emission zones in OLEDs. As a result, an alteration of the chemical design of the materials allows for the control of the emissive region location within the EML. By chemical modification of the host molecule, we achieved a relocation of the emissive zone in blue OLEDs from the EML/ETL interface to the EML/HTL interface.

Padmaperuma, Asanga; Polikarpov, Evgueni; Swensen, James; Cosimbescu, Lelia; Koech, Phillip; Wang, Liang

2010-03-01

194

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

195

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

SciTech Connect

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

NONE

1995-07-14

196

Multiscale materials design of natural exoskeletons : fish armor  

E-print Network

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

Song, Juha

2011-01-01

197

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

198

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

PubMed

Eutectics are a long known class of multi-component solids with important and useful applications in daily life. In comparison to other multi-component crystalline solids, such as salts, solid solutions, molecular complexes and cocrystals, eutectics are less studied in terms of molecular structure organization and bonding interactions. Classically, a eutectic is defined based on its low melting point compared to the individual components. In this article, we attempt to define eutectics not just based on thermal methods but from a structural organization view point, and discuss their microstructures and properties as organic materials vis-a-vis solid solutions and cocrystals. The X-ray crystal structure of a cocrystal is different from that of the individual components whereas the unit cell of a solid solution is similar to that of one of the components. Eutectics are closer to the latter species in that their crystalline arrangement is similar to the parent components but they are different with respect to the structural integrity. A solid solution possesses structural homogeneity throughout the structure (single phase) but a eutectic is a heterogeneous ensemble of individual components whose crystal structures are like discontinuous solid solutions (phase separated). Thus, a eutectic may be better defined as a conglomerate of solid solutions. A structural analysis of cocrystals, solid solutions and eutectics has led to an understanding that materials with strong adhesive (hetero) interactions between the unlike components will lead to cocrystals whereas those having stronger cohesive (homo/self) interactions will more often give rise to solid solutions (for similar structures of components) and eutectics (for different structures of components). We demonstrate that the same crystal engineering principles which have been profitably utilized for cocrystal design in the past decade can now be applied to make eutectics as novel composite materials, illustrated by stable eutectics of the hygroscopic salt of the anti-tuberculosis drug ethambutol as a case study. A current gap in the characterization of eutectic microstructure may be fulfilled through pair distribution function (PDF) analysis of X-ray diffraction data, which could be a rapid signature technique to differentiate eutectics from their components. PMID:24322207

Cherukuvada, Suryanarayan; Nangia, Ashwini

2014-01-28

199

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

200

Fab trees for designing complex 3D printable materials  

E-print Network

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

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

2013-01-01

201

Design and material selection for inverter transformer cores  

NASA Technical Reports Server (NTRS)

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

Mclyman, W. T.

1973-01-01

202

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

203

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

ERIC Educational Resources Information Center

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

Potter, Patricia

2013-01-01

204

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

NSDL National Science Digital Library

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

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

2007-03-01

205

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

Code of Federal Regulations, 2010 CFR

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

2010-10-01

206

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

NASA Astrophysics Data System (ADS)

The field of meta-materials engineering has largely expanded mechanical design possibilities over the last two decades; some notable design advances include the systematic engineering of negative Poisson's ratio materials and functionally graded materials, materials designed for optimal electronic and thermo-mechanical performances, and the design of materials under uncertainty. With these innovations, the systematic engineering of materials for design-specific uses is becoming more common in industrial and military uses. The motivation for this body of research is the design of the shear beam for a non-pneumatic wheel. Previously, a design optimization of a finite element model of the non-pneumatic wheel was completed, where a linear elastic material was simulated in the shear beam to reduce hysteretic energy losses. As part of the optimization, a set of optimal orthotropic material properties and other geometric properties were identified for the shear beam. Given that no such natural linear elastic material exists, a meta-material can be engineered that meets these properties using the aforementioned tools. However, manufacturing constraints prevent the use of standard homogenization analysis and optimization tools in the engineering of the shear beam due to limitations in the accuracy of the homogenization process for thin materials. In this research, the more general volume averaging analysis is shown to be an accurate tool for meta-material analysis for engineering thin-layered materials. Given an accurate analysis method, several optimization formulations are proposed, and optimality conditions are derived to determine the most mathematically feasible and numerically reliable formulation for topology optimization of a material design problem using a continuous material interpolation over the design domain. This formulation is implemented to engineer meta-materials for problems using the volume averaging analysis, which includes the use of variable linking and the derivation of first-order design sensitivities to increase computational efficiency. Inspired by honeycomb materials, a new method of discretizing the material design domain into unit cells with non-simple connectivity is proposed as a way of increasing the solution space of the topology optimization problem. Finally, these methods are used in the meta-material design process to identify several candidate meta-material geometries from a polycarbonate base material for the shear layer of the non-pneumatic wheel; notable geometries include an 'x'-like geometry, a bent column-like geometry identified previously as a bristle, and, remarkably, an auxetic honeycomb geometry. This is the first reported result demonstrating the auxetic honeycomb geometry to be a minimum weight structure in shear loading where a general topology optimization method was used.

Czech, Christopher

207

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

208

[Molecular design of polymeric materials for biotechnology and medicine].  

PubMed

This review describes new polymer materials for biomedical applications developed in the Polymers for Biology Laboratory of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences. These include composite rigid sorbents for biochromatography, polymer dispersions for immunoassay, polymer hydrogels for immobilization of enzymes and cells, and polymer ultra thin films as biomembrane models and materials for biosensors. Some general and specific properties of these new materials and models as well as examples of their applications are discussed. PMID:10645492

Zubov, V P; Ivanov, A E; Zhigis, L S; Rapoport, E M; Markvicheva, E A; Lukin, Iu V; Za?tsev, S Iu

1999-11-01

209

Material Characterization and Design Recommendations for Mechanically Stabilized Earth Retaining Walls  

E-print Network

the Federal Highway Administration and American Association of State Highway and Transportation Officials (AASHTO) guidelines for design of MSE walls. The research addresses three main issues expressed by TxDOT in their design and material selection process...

Dantal, Vishal

2013-12-04

210

Materials by Design—A Perspective From Atoms to Structures  

PubMed Central

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

Buehler, Markus J.

2013-01-01

211

Materials by Design-A Perspective From Atoms to Structures.  

PubMed

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

Buehler, Markus J

2013-02-01

212

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

ERIC Educational Resources Information Center

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

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

2007-01-01

213

Material and design considerations for the carbon armored ITER divertor  

NASA Astrophysics Data System (ADS)

The properties of materials for the carbon armored ITER divertor were evaluated from literature and manufacturers' documentation. Most of these data, however, have been not known or not published yet. We have evaluated an optimum data set of the candidate materials of the ITER divertor, which were needed for finite element analyses (FEM). The materials evaluated are as follows; MFC-1, CX2002U, SEP-N112, P-130, IG-430U for the carbon based materials, and Oxygen Free Copper (OFCu), Dispersion Strengthened Copper (DSCu), TZM, W5Re and W-Cu as a heat sink material. It should be noted that W-Cu is first proposed for a heat sink application of the ITER divertor plate. The finite element analyses were performed for the residual stress induced by brazing, thermal response and thermal stresses under a uniform heat flux of 15 MW/sq m to the plasma facing surface. The stress free temperature of 750 C is assumed for the residual stress by brazing. Ten different geometries of the divertor were considered in the analyses including possible material combinations. The FEM results show that the material combinations of MFC-1 and W-30Cu or DSUc in the flat-plate geometry satisfy the presently accepted ITER requirements. The combinations of CX2002U and TZM or W5Re is considered a good choice in terms of residual and thermal stresses, whereas the surface temperature exceeds the ITER requirements.

Smid, I.; Akiba, Masato; Araki, Masanori; Suzuki, Satoshi; Satoh, Kazuyoshi

1993-07-01

214

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

Microsoft Academic Search

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

Marcelo Coelho

215

Designer disordered materials with large, complete photonic band gaps  

E-print Network

of 2D, isotropic, disordered, photonic materials of arbitrary size with complete band gaps blocking all, including efficient radiation sources (3), sensors (4), and optical computer chips (5). To date, although

Torquato, Salvatore

216

Design of novel lithium storage materials with a polyanionic framework  

E-print Network

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

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

2014-01-01

217

Use of UHPC in Bridge Structures: Material Modeling and Design  

E-print Network

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

Gunes, Oguz

218

First Materials Science Research Rack Capabilities and Design Features  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

219

30 CFR 18.92 - Quality of material and design.  

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field Approval of Electrically Operated Mining Equipment § 18.92 Quality of material and...

2014-07-01

220

30 CFR 18.92 - Quality of material and design.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field Approval of Electrically Operated Mining Equipment § 18.92 Quality of material and...

2013-07-01

221

30 CFR 18.92 - Quality of material and design.  

Code of Federal Regulations, 2011 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field Approval of Electrically Operated Mining Equipment § 18.92 Quality of material and...

2011-07-01

222

30 CFR 18.92 - Quality of material and design.  

Code of Federal Regulations, 2012 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field Approval of Electrically Operated Mining Equipment § 18.92 Quality of material and...

2012-07-01

223

30 CFR 18.92 - Quality of material and design.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Field Approval of Electrically Operated Mining Equipment § 18.92 Quality of material and...

2010-07-01

224

Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth.  

PubMed

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

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

2014-05-15

225

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

226

Designing Web-Based Educative Curriculum Materials for the Social Studies  

ERIC Educational Resources Information Center

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

Callahan, Cory; Saye, John; Brush, Thomas

2013-01-01

227

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

228

ANL/ALCF/ESP-13/2 Materials Design and Discovery: Catalysis and  

E-print Network

ANL/ALCF/ESP-13/2 Materials Design and Discovery: Catalysis and Energy Storage (Mira Early Science Laboratory, or UChicago Argonne, LLC. #12;ANL/ALCF/ESP-13/2 Materials Design and Discovery: Catalysis Theory (DFT), and quantum Monte Carlo (QMC). The original scope for this Early Science Program (ESP

Kemner, Ken

229

New Materials Design Through Friction Stir Processing Techniques  

NASA Astrophysics Data System (ADS)

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

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

2007-04-01

230

Microstructure Optimization in Fuel Cell Electrodes using Materials Design  

SciTech Connect

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

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

2006-08-01

231

Materials technology assessment for a 1050 K Stirling Space Engine design  

SciTech Connect

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

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

1988-10-01

232

Materials technology assessment for a 1050 K Stirling space engine design  

NASA Technical Reports Server (NTRS)

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

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

1988-01-01

233

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

234

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

235

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

236

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

ERIC Educational Resources Information Center

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…

Wendell, Kristen Bethke; Lee, Hee-Sun

2010-01-01

237

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

E-print Network

thermoelectric materials T. Koga,a) X. Sun, S. B. Cronin, and M. S. Dresselhausb) Department of Physics to provide a promising strategy for designing materials with a large thermoelectric figure of merit ZT is already a good thermoelectric material, 3 the reduction of the lattice ther- mal conductivity ph due

Cronin, Steve

238

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

E-print Network

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

Paris-Sud XI, Université de

239

Design of a scientific probe for obtaining Mars surface material  

NASA Technical Reports Server (NTRS)

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

1990-01-01

240

Advanced elastomeric seal design and material for automotive crankshaft applications  

Microsoft Academic Search

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

R. Jackowski; R. Keller; D. Strubel

1987-01-01

241

Photovoltaic module encapsulation design and materials section, volume 2  

NASA Technical Reports Server (NTRS)

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

Cuddihy, E. F.

1984-01-01

242

Designing for time-dependent material response in spacecraft structures  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

243

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

NASA Astrophysics Data System (ADS)

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

Barthelat, Francois

2014-12-01

244

Nonstoichiometric Laser Materials: Designer Wavelengths in Neodymium Doped Garnets  

NASA Technical Reports Server (NTRS)

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

Walsh, Brian M.; Barnes, Norman P.

2008-01-01

245

Master's Degree Learners' Use of Theory in Designing Instructional Materials  

ERIC Educational Resources Information Center

Educational institutions offering a master's degree program in instructional design incorporate instructional design theory into the master's degree course offerings. The responsibility for the student is to develop coursework. Master's degree learners will use instructional design theory to develop course materials. This study…

Wojtecki, John A.

2012-01-01

246

POLYVINYL ALCOHOL FIBER REINFORCED ENGINEERED CEMENTITIOUS COMPOSITES: MATERIAL DESIGN AND PERFORMANCES  

Microsoft Academic Search

Polyvinyl alcohol (PVA) fiber is considered as one of the most suitable polymeric fibers to be used as the reinforcement of engineered cementitious composites (ECC), though the unique microstructure characteristics of PVA fiber add challenge to the material design. In this paper, the micromechanics based design procedure for a PVA-ECC suitable for structural applications is described, and practical design considerations

Shuxin Wang; Victor C. Li

247

Materials Selection and Design of Microelectrothermal Bimaterial Actuators  

Microsoft Academic Search

A common form of MEMS actuator is a thermally actuated bimaterial, which is easy to fabricate by surface micromachining and permits out of plane actuation, which is otherwise difficult to achieve. This paper presents an analytical framework for the design of such microelectrothermal bimaterial actuators. Mechanics relationships for a cantilever bimaterial strip subjected to a uniform temperature were applied to

Srinivasan Prasanna; S. Mark Spearing

2007-01-01

248

Evolutionary Design of a Robotic Material Defect Detection System  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

249

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

250

Self-expanding nitinol stents: material and design considerations.  

PubMed

Nitinol (nickel-titanium) alloys exhibit a combination of properties which make these alloys particularly suited for self-expanding stents. Some of these properties cannot be found in engineering materials used for stents presently. This article explains the fundamental mechanism of shape memory and superelasticity, and how they relate to the characteristic performance of self-expanding stents. Nitinol stents are manufactured to a size slightly larger than the target vessel size and delivered constrained in a delivery system. After deployment, they position themselves against the vessel wall with a low, "chronic" outward force. They resist outside forces with a significantly higher radial resistive force. Despite the high nickel content of Nitinol, its corrosion resistance and biocompatibility is equal to that of other implant materials. The most common Nitinol stents are listed and described. PMID:12955452

Stoeckel, Dieter; Pelton, Alan; Duerig, Tom

2004-02-01

251

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

252

Biochemically designed polymers as self-organized materials  

NASA Astrophysics Data System (ADS)

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

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

1997-02-01

253

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

254

SRM nozzle design breakthroughs with advanced composite materials  

NASA Astrophysics Data System (ADS)

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

Berdoyes, Michel

1993-06-01

255

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

256

First Materials Science Research Facility Rack Capabilities and Design Features  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

257

Design of responsive materials using topologically interlocked elements  

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

258

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

259

Effects of Buckling Knockdown Factor, Internal Pressure and Material on the Design of Stiffened Cylinders  

NASA Technical Reports Server (NTRS)

A design study was conducted to investigate the effect shell buckling knockdown factor (SBKF), internal pressure and aluminum alloy material selection on the structural weight of stiffened cylindrical shells. Two structural optimization codes were used for the design study to determine the optimum minimum-weight design for a series of design cases, and included an in-house developed genetic algorithm (GA) code and PANDA2. Each design case specified a unique set of geometry, material, knockdown factor combinations and loads. The resulting designs were examined and compared to determine the effects of SBKF, internal pressure and material selection on the acreage design weight and controlling failure mode. This design study shows that use of less conservative SBKF values, including internal pressure, and proper selection of material alloy can result in significant weight savings for stiffened cylinders. In particular, buckling-critical cylinders with integrally machined stiffener construction can benefit from the use of thicker plate material that enables taller stiffeners, even when the stiffness, strength and density properties of these materials appear to be inferior.

Lovejoy, Andrew E.; Hilburger, Mark W.; Chunchu, Prasad B.

2010-01-01

260

Microwave Nondestructive Evaluation of Dielectric Materials with a Metamaterial Lens  

NASA Technical Reports Server (NTRS)

A novel microwave Nondestructive Evaluation (NDE) sensor was developed in an attempt to increase the sensitivity of the microwave NDE method for detection of defects small relative to a wavelength. The sensor was designed on the basis of a negative index material (NIM) lens. Characterization of the lens was performed to determine its resonant frequency, index of refraction, focus spot size, and optimal focusing length (for proper sample location). A sub-wavelength spot size (3 dB) of 0.48 lambda was obtained. The proof of concept for the sensor was achieved when a fiberglass sample with a 3 mm diameter through hole (perpendicular to the propagation direction of the wave) was tested. The hole was successfully detected with an 8.2 cm wavelength electromagnetic wave. This method is able to detect a defect that is 0.037 lambda. This method has certain advantages over other far field and near field microwave NDE methods currently in use.

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

2008-01-01

261

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

NASA Technical Reports Server (NTRS)

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.

1982-01-01

262

Decoupling interrelated parameters for designing high performance thermoelectric materials.  

PubMed

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

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

2014-04-15

263

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

PubMed

We propose a procedure to rank the most interesting solutions from high-throughput materials design studies. Such a tool is becoming indispensable due to the growing size of computational screening studies and the large number of criteria involved in realistic materials design. As a proof of principle, the binary tungsten alloys are screened for both large-weight and high-impact materials, as well as for fusion reactor applications. Moreover, the concept is generally applicable to any design problem where multiple competing criteria have to be optimized. PMID:23992074

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

2013-08-16

264

Multi-criteria decision making and uncertainty analysis for materials selection in environmentally conscious design  

Microsoft Academic Search

Around the globe, manufacturers are increasingly trying to design products that are as ecological as possible, which is leading\\u000a to the establishment of new design methods focused on environmentally conscious design (ECD). Materials selection, as a key\\u000a element in ECD, differs from traditional design by introducing three additional requirements: life cycle viewpoint, consideration\\u000a on environmental impact and cost, and uncertainties

Haihong Huang; Lei Zhang; Zhifeng Liu; John W. Sutherland

2011-01-01

265

Ionomer Design Principles for Single Ion-Conducting Energy Materials  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

266

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

E-print Network

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

Kwan, Joyce G

2013-01-01

267

Computational Design of Photovoltaic Materials with Self Organized Nano Structures  

NASA Astrophysics Data System (ADS)

Chalcopyrite and II-VI semiconductors, such as Cu(In, Ga)Se2, Cu2ZnSn(S, Se)4 and Cd(S, Te), are one of the most promising materials for low cost photovoltaic solar-cells. In this paper, based on first-principles calculations, we propose that self-organized nano-structures in these compounds will enhance the conversion efficiency. Our calculations are based on the KKR-CPA-LDA [1] with the self-interaction correction [2]. We also use VASP package [3] for calculating mixing energy and effective interactions of the systems by using the cluster expansion method [4]. For phase separating systems, we simulate nano-structure formation by using the Monte Carlo method. It is expected that the photo-generated electron-hole pairs are efficiently separated by the type-II interface and then effectively transferred along the quasi-one-dimensional structures. Moreover, we can expect multiplication of generated carriers due to the multi-exciton effects in nano-structures [5]. [4pt] [1] H. Akai, http://sham.phys.sci.osaka-u.ac.jp/kkr/[0pt] [2] A. Filippetti and N. A. Spaldin, PRB 67 (2003) 125109.[0pt] [3] G. Kresse and J. Hafner, PRB 47 (1993) 558.[0pt] [4] A. Zunger, NATO ASI B 319 (1994) 361.[0pt] [5] Y. Tani et al., APEX 3 (2010) 101201, 4 (2011) 021201, JJAP 51 (2012) 050202.

Sato, Kazunori; Katayama-Yoshida, Hiroshi

2013-03-01

268

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

SciTech Connect

To facilitate materials selection, structural design, and future maintenance of the Generation IV nuclear reactor systems, an interactive, internet accessible materials property database, dubbed Gen IV Materials Handbook, has been under development with the support of the United States Department of Energy. The Handbook will provide an authoritative source of information on structural materials needed for the development of various Gen IV nuclear reactor systems along with powerful data analysis and management tools. In this paper, the background, history, framework, major features, contents, and development strategy of the Gen IV Materials Handbook are discussed. Current development status and future plans are also elucidated.

Ren, Weiju [ORNL

2008-01-01

269

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

Microsoft Academic Search

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

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

2007-01-01

270

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

Microsoft Academic Search

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

De-Liang Long; Eric Burkholder; Leroy Cronin

2007-01-01

271

Soft materials design via self assembly of functionalized icosahedral particles  

NASA Astrophysics Data System (ADS)

In this work we simulate self assembly of icosahedral building blocks using a coarse grained model of the icosahedral capsid of virus 1m1c. With significant advancements in site-directed functionalization of these macromolecules [1], we propose possible application of such self-assembled materials for drug delivery. While there have been some reports on organization of viral particles in solution through functionalization, exploiting this behaviour for obtaining well-ordered stoichiometric structures has not yet been explored. Our work is in well agreement with the earlier simulation studies of icosahedral gold nanocrystals, giving chain like patterns [5] and also broadly in agreement with the wet lab works of Finn, M.G. et al., who have shown small predominantly chain-like aggregates with mannose-decorated Cowpea Mosaic Virus (CPMV) [22] and small two dimensional aggregates with oligonucleotide functionalization on the CPMV capsid [1]. To quantify the results of our Coarse Grained Molecular Dynamics Simulations I developed analysis routines in MATLAB using which we found the most preferable nearest neighbour distances (from the radial distribution function (RDF) calculations) for different lengths of the functional groups and under different implicit solvent conditions, and the most frequent coordination number for a virus particle (histogram plots further using the information from RDF). Visual inspection suggests that our results most likely span the low temperature limits explored in the works of Finn, M.G. et al., and show a good degree of agreement with the experimental results in [1] at an annealing temperature of 4°C. Our work also reveals the possibility of novel stoichiometric N-mer type aggregates which could be synthesized using these capsids with appropriate functionalization and solvent conditions.

Muthukumar, Vidyalakshmi Chockalingam

272

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

E-print Network

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

273

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

ERIC Educational Resources Information Center

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

Ellison, John W.

274

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

E-print Network

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

Nagi, Rakesh

275

PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices  

E-print Network

PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices Yoav of material with embedded electronics such as PCB (Printed Circuit Boards) as the medium for origami folding functionalities. PCBs are produced as 2D shapes. By folding PCB arrays it is possible to create 3D objects

Demaine, Erik

276

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

277

Learning to Design and Analyze Materials Handling Systems: Developing Multimedia Tools  

ERIC Educational Resources Information Center

In this paper, we describe aspects related to learning and learning assessment including pedagogy, cognition, pilot study and results from the study. This study is conducted for an educational module on "10 Principles of Materials Handling". This module along with another on "Analysis and Design of Integrated Materials Handling Systems" constitute…

Heragu, Sunderesh; Jennings, Sybillyn

2003-01-01

278

SHAPE AND MATERIAL DESIGN IN PHYSICAL MODELING SOUND SYNTHESIS Pirouz Djoharian  

E-print Network

SHAPE AND MATERIAL DESIGN IN PHYSICAL MODELING SOUND SYNTHESIS Pirouz Djoharian A.C.R.O.E. 46 generation processes existing in various acoustic musical instruments. Thus, Physical Modeling sound is what we refer to the sound signature of the material. At the final step, the physical model ends up

Paris-Sud XI, Université de

279

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

280

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

281

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

282

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

283

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

284

Design of a smart textile mat to study pressure distribution on multiple foam material configurations  

Microsoft Academic Search

In this paper, we present a design of a smart textile pressure mat to study the pressure distribution with multiple foam material configurations for neonatal monitoring at Neonatal Intensive Care Units (NICU). A smart textile mat with 64 pressure sensors has been developed including software at the Department of Industrial Design, Eindhoven University of Technology (TU\\/e). The developed sensory mat

Rik van Donselaar; Wei Chen

2011-01-01

285

Representing Clarity: Using Universal Design Principles to Create Effective Hybrid Course Learning Materials  

ERIC Educational Resources Information Center

This article describes how the author applied principles of universal design to hybrid course materials to increase student understanding and, ultimately, success. Pulling the three principles of universal design--consistency, color, and icon representation--into the author's Blackboard course allowed her to change the types of reading skills…

Spiegel, Cheri Lemieux

2012-01-01

286

The synergistic effects of slip ring-brush design and materials  

NASA Technical Reports Server (NTRS)

The design, fabrication, and subsequent testing of four power slip rings for synchronous orbit application are described. The synergistic effects of contact materials and slip ring-brush design are studied by means of frequent and simultaneous recording of friction, wear, and electrical noise. Data generated during the test period are presented along with post test analysis data.

Lewis, N. E.; Cole, S. R.; Glossbrenner, E. W.

1974-01-01

287

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

NASA Technical Reports Server (NTRS)

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

Rodriguez, Pedro I.

1993-01-01

288

Packing design and materials for coal liquefaction slurry feed pumps. Interim Technical Report No. 2  

SciTech Connect

Seven packing vendors responded to MTI's solicitation and provided packing designs and materials for coal liquefaction slurry feed pumps at the existing pilot plants. The pilot plants include EDS at Baytown, Texas, H-Coal at Catlettsburg, Kentucky, and SRC-I at Wilsonville, Alabama. Two basic types of packing designs were proposed by the vendors. The first type is the compression or jam type of pre-molded or cut-fit packing design. The options include up to eight rings of either identical or a combination of soft and hard packing material with or without end adapters. The second type of design proposed to the program is a chevron shaped and spring loaded type of pre-molded packing. The options include two to four rings of homogeneous and/or composite packing material with end adapters or spacers.

Not Available

1982-02-18

289

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

PubMed Central

Halogen bonding is an emerging noncovalent interaction for constructing supramolecular assemblies. Though similar to the more familiar hydrogen bonding, four primary differences between these two interactions make halogen bonding a unique tool for molecular recognition and the design of functional materials. First, halogen bonds tend to be much more directional than (single) hydrogen bonds. Second, the interaction strength scales with the polarizability of the bond-donor atom, a feature that researchers can tune through single-atom mutation. In addition, halogen bonds are hydrophobic whereas hydrogen bonds are hydrophilic. Lastly, the size of the bond-donor atom (halogen) is significantly larger than hydrogen. As a result, halogen bonding provides supramolecular chemists with design tools that cannot be easily met with other types of noncovalent interactions and opens up unprecedented possibilities in the design of smart functional materials. This Account highlights the recent advances in the design of halogen-bond-based functional materials. Each of the unique features of halogen bonding, directionality, tunable interaction strength, hydrophobicity, and large donor atom size, makes a difference. Taking advantage of the hydrophobicity, researchers have designed small-size ion transporters. The large halogen atom size provided a platform for constructing all-organic light-emitting crystals that efficiently generate triplet electrons and have a high phosphorescence quantum yield. The tunable interaction strengths provide tools for understanding light-induced macroscopic motions in photoresponsive azobenzene-containing polymers, and the directionality renders halogen bonding useful in the design on functional supramolecular liquid crystals and gel-phase materials. Although halogen bond based functional materials design is still in its infancy, we foresee a bright future for this field. We expect that materials designed based on halogen bonding could lead to applications in biomimetics, optics/photonics, functional surfaces, and photoswitchable supramolecules. PMID:23805801

2013-01-01

290

Identifying target properties for the design of meta-material tank track pads  

NASA Astrophysics Data System (ADS)

On track vehicle systems, track pads are designed to provide traction and support the weight of the vehicle, they have limited service life due to common failure by blowout. According to the literature, blowout is a failure mode caused by overheating due to hysteresis in elastomeric materials during high speed operations. Elastomers are used primarily for their high compliance, which is essential to protect the suspension components and maintain structural integrity of the track pad. The objective of the work is to explore the use of linear elastic meta-materials with optimized topology to replace elastomers and reduce or eliminate the effect of hysteretic loss. This work presents a methodology to design an alternate meta-material that can provide some of the desired elastic properties of the track pads. To determine the requirements for linear elastic meta-materials, dynamic analyses of a rollover event were conducted. From these analyses the complex dependence of the strain history on different strain components is understood. Due to the non-linearity of elastomers, tangent stiffness matrices are required to update the stress states at different strain increments. The elasticity tensors (tangent operators) determined at a set of strain levels, are used as prescribed constitutive parameters to tailor the meta-material unit-cell topology. The optimal material properties according to which the elastomeric track pad is designed with linear elastic material are identified in this work.

Dangeti, Venkata Sampath

291

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

292

Data mining for materials design: A computational study of single molecule magnet  

NASA Astrophysics Data System (ADS)

We develop a method that combines data mining and first principles calculation to guide the designing of distorted cubane Mn4 +Mn^{3+}_3 single molecule magnets. The essential idea of the method is a process consisting of sparse regressions and cross-validation for analyzing calculated data of the materials. The method allows us to demonstrate that the exchange coupling between Mn4 + and Mn3 + ions can be predicted from the electronegativities of constituent ligands and the structural features of the molecule by a linear regression model with high accuracy. The relations between the structural features and magnetic properties of the materials are quantitatively and consistently evaluated and presented by a graph. We also discuss the properties of the materials and guide the material design basing on the obtained results.

Dam, Hieu Chi; Pham, Tien Lam; Ho, Tu Bao; Nguyen, Anh Tuan; Nguyen, Viet Cuong

2014-01-01

293

Data mining for materials design: A computational study of single molecule magnet  

SciTech Connect

We develop a method that combines data mining and first principles calculation to guide the designing of distorted cubane Mn{sup 4+} Mn {sub 3}{sup 3+} single molecule magnets. The essential idea of the method is a process consisting of sparse regressions and cross-validation for analyzing calculated data of the materials. The method allows us to demonstrate that the exchange coupling between Mn{sup 4+} and Mn{sup 3+} ions can be predicted from the electronegativities of constituent ligands and the structural features of the molecule by a linear regression model with high accuracy. The relations between the structural features and magnetic properties of the materials are quantitatively and consistently evaluated and presented by a graph. We also discuss the properties of the materials and guide the material design basing on the obtained results.

Dam, Hieu Chi [Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan) [Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Faculty of Physics, Vietnam National University, 334 Nguyen Trai, Hanoi (Viet Nam); Pham, Tien Lam; Ho, Tu Bao [Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)] [Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Nguyen, Anh Tuan [Faculty of Physics, Vietnam National University, 334 Nguyen Trai, Hanoi (Viet Nam)] [Faculty of Physics, Vietnam National University, 334 Nguyen Trai, Hanoi (Viet Nam); Nguyen, Viet Cuong [HPC Systems, Inc., 3-9-15 Kaigan, Minato-ku, Tokyo 108-0022 (Japan)] [HPC Systems, Inc., 3-9-15 Kaigan, Minato-ku, Tokyo 108-0022 (Japan)

2014-01-28

294

Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies  

SciTech Connect

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

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

2005-04-15

295

Sustainable manufacturing: Effect of material selection and design on the environmental impact in the manufacturing process  

NASA Astrophysics Data System (ADS)

The environmental impact of a manufacturing process is also dependent on the selection of the material and design of a product. This is because the manufacturing of a product is directly connected to the amount of carbon emitted in consuming the electrical energy for that manufacturing process. The difference in the general properties of materials such as strength, hardness and impact will have significant effect on the power consumption of the machine used to complete the product. In addition the environmental impact can also be reduced if the proposed designs use less material. In this study, an LCA tool called Eco-It is used. Evaluate the environmental impact caused by manufacturing simple jig. A simple jig with 4 parts was used as a case study. Two experiments were carried out. The first experiment was to study the environmental effects of different material, and the second experiment was to study the environmental impact of different design. The materials used for the jig are Aluminium and mild steel. The results showed a decrease in the rate of carbon emissions by 60% when Aluminium is use instead from mild steel, and a decrease of 26% when the-design is modified.

Hazwan Syafiq Harun, Mohd; Taha, Zahari; Salaam, Hadi Abdul

2013-12-01

296

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

297

Advanced composites structural concepts and materials technologies for primary aircraft structures: Design/manufacturing concept assessment  

NASA Technical Reports Server (NTRS)

Composite Wing and Fuselage Structural Design/Manufacturing Concepts have been developed and evaluated. Trade studies were performed to determine how well the concepts satisfy the program goals of 25 percent cost savings, 40 percent weight savings with aircraft resizing, and 50 percent part count reduction as compared to the aluminum Lockheed L-1011 baseline. The concepts developed using emerging technologies such as large scale resin transfer molding (RTM), automatic tow placed (ATP), braiding, out-of-autoclave and automated manufacturing processes for both thermoset and thermoplastic materials were evaluated for possible application in the design concepts. Trade studies were used to determine which concepts carry into the detailed design development subtask.

Chu, Robert L.; Bayha, Tom D.; Davis, HU; Ingram, J. ED; Shukla, Jay G.

1992-01-01

298

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

299

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

300

Taguchi statistical design and analysis of cleaning methods for spacecraft materials  

NASA Technical Reports Server (NTRS)

In this study, we have extensively tested various cleaning protocols. The variant parameters included the type and concentration of solvent, type of wipe, pretreatment conditions, and various rinsing systems. Taguchi statistical method was used to design and evaluate various cleaning conditions on ten common spacecraft materials.

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

2003-01-01

301

Designing synthetic materials to control stem cell phenotype Krishanu Saha1,*  

E-print Network

and differentiation ex vivo, tissue regeneration via implantation with stem cells, or implantation alone to directDesigning synthetic materials to control stem cell phenotype Krishanu Saha1,* , Jacob F Pollock2,3,* , David V Schaffer1,4 and Kevin E Healy2,3,5 The micro-environment in which stem cells reside regulates

Saha, Krishanu

302

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

303

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

E-print Network

exchange surfaces without sacrificing the heat transfer performance. A scholarship is available for studyAbove Ground Geothermal and Allied Technologies Masters Scholarship in Energy & Materials: design into the largest green energy resources; industrial waste heat, biomass combustion and geothermal energy. Research

Hickman, Mark

304

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

E-print Network

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

Harilal, S. S.

305

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

E-print Network

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

306

Design, Implementation, and Evaluation of GIS-Based Learning Materials in an Introductory Geoscience Course.  

ERIC Educational Resources Information Center

Investigates student learning that occurred with a Geographic Information Systems (GIS) based module on plate tectonics and geologic hazards. Examines factors in the design and implementation of the materials that impacted student learning. Reports positive correlations between student' spatial ability and performance. Includes 17 references.…

Hall-Wallace, Michelle K.; McAuliffe, Carla M.

2002-01-01

307

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

ERIC Educational Resources Information Center

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

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

2010-01-01

308

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

309

Accelerating the Design of Solar Thermal Fuel Materials through High Throughput Simulations.  

PubMed

Solar thermal fuels (STF) store the energy of sunlight, which can then be released later in the form of heat, offering an emission-free and renewable solution for both solar energy conversion and storage. However, this approach is currently limited by the lack of low-cost materials with high energy density and high stability. In this Letter, we present an ab initio high-throughput computational approach to accelerate the design process and allow for searches over a broad class of materials. The high-throughput screening platform we have developed can run through large numbers of molecules composed of earth-abundant elements and identifies possible metastable structures of a given material. Corresponding isomerization enthalpies associated with the metastable structures are then computed. Using this high-throughput simulation approach, we have discovered molecular structures with high isomerization enthalpies that have the potential to be new candidates for high-energy density STF. We have also discovered physical principles to guide further STF materials design through structural analysis. More broadly, our results illustrate the potential of using high-throughput ab initio simulations to design materials that undergo targeted structural transitions. PMID:25372463

Liu, Yun; Grossman, Jeffrey C

2014-12-10

310

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

NASA Astrophysics Data System (ADS)

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

Notghi, Bahram; Brigham, John C.

2013-12-01

311

Preliminary design polymeric materials experiment. [for space shuttles and Spacelab missions  

NASA Technical Reports Server (NTRS)

A typical Advanced Technology Laboratory mission flight plan was developed and used as a guideline for the identification of a number of experiment considerations. The experiment logistics beginning with sample preparation and ending with sample analysis are then overlaid on the mission in order to have a complete picture of the design requirements. The results of this preliminary design study fall into two categories. First specific preliminary designs of experiment hardware which is adaptable to a variety of mission requirements. Second, identification of those mission considerations which affect hardware design and will require further definition prior to final design. Finally, a program plan is presented which will provide the necessary experiment hardware in a realistic time period to match the planned shuttle flights. A bibliography of all material reviewed and consulted but not specifically referenced is provided.

Mattingly, S. G.; Rude, E. T.; Marshner, R. L.

1975-01-01

312

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

313

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

314

Criteria for design with structural materials in combined-cycle applications above 815 F  

NASA Astrophysics Data System (ADS)

A number of materials issues related to the design of piping and support components in high-temperature fluidized bed combustor systems were examined. These issues included 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 was placed on alloy 800H, but several other alloys were briefly examined for use at temperatures above 816 deg C (1500 deg F). It was concluded 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 deg C (1500 deg F).

Swindeman, R. W.; Marriott, D. L.

1994-04-01

315

Metal-organic Frameworks as A Tunable Platform for Designing Functional Molecular Materials  

PubMed Central

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

Wang, Cheng; Liu, Demin

2013-01-01

316

Specimen Designs for Testing Advanced Aeropropulsion Materials Under In-Plane Biaxial Loading  

NASA Technical Reports Server (NTRS)

A design study was undertaken to develop specimen designs for testing advanced aeropropulsion materials under in-plane biaxial loading. The focus of initial work was on developing a specimen design suitable for deformation and strength tests to be conducted under monotonic loading. The type of loading initially assumed in this study was the special case of equibiaxial, tensile loading. A specimen design was successfully developed after a lengthy design and optimization process with overall dimensions of 12 by 12 by 0.625 in., and a gage area of 3.875 by 3.875 by 0.080 in. Subsequently, the scope of the work was extended to include the development of a second design tailored for tests involving cyclic loading. A specimen design suitably tailored to meet these requirements was successfully developed with overall dimensions of 12 by 12 by 0.500 in. and a gage area of 2.375 by 2.375 by 0.050 in. Finally, an investigation was made to determine whether the specimen designs developed in this study for equibiaxial, tensile loading could be used without modification to investigate general forms of biaxial loading. For best results, it was concluded that specimen designs need to be optimized and tailored to meet the specific loading requirements of individual research programs.

Ellis, John R.; Abul-Aziz, Ali

2003-01-01

317

Fusion Engineering and Design 3940 (1998) 287294 Response of plasma-facing materials to high transient heat  

E-print Network

Fusion Engineering and Design 39­40 (1998) 287­294 Response of plasma-facing materials to high from a plasma onto a material surface triggers a sequence of dynamic plasma­material interaction experiments were carried out in the TEXTOR tokamak. The materials exposed to the plasma were carbon fibre

Harilal, S. S.

318

New classes of piezoelectrics, ferroelectrics, and antiferroelectrics by first-principles high-throughput materials design  

NASA Astrophysics Data System (ADS)

Functional materials, such as piezoelectrics, ferroelectrics, and antiferroelectrics, exhibit large changes with applied fields and stresses. This behavior enables their incorporation into a wide variety of devices in technological fields such as energy conversion/storage and information processing/storage. Discovery of functional materials with improved performance or even new types of responses is thus not only a scientific challenge, but can have major impacts on society. In this talk I will review our efforts to uncover new families of functional materials using a combined crystallographic database/high-throughput first-principles approach. I will describe our work on the design and discovery of thousands of new functional materials, specifically the LiAlSi family as piezoelectrics, the LiGaGe family as ferroelectrics, and the MgSrSi family as antiferroelectrics.

Bennett, Joseph

2013-03-01

319

Dynamic simulation of stent deployment - effects of design, material and coating  

NASA Astrophysics Data System (ADS)

Dynamic finite-element simulations have been carried out to study the effects of cell design, material choice and drug eluting coating on the mechanical behaviour of stents during deployment. Four representative stent designs have been considered, i.e., Palmaz-Schatz, Cypher, Xience and Endeavor. The former two are made of stainless steel while the latter two made of Co-Cr alloy. Geometric model for each design was created using ProEngineer software, and then imported into Abaqus for simulation of the full process of stent deployment within a diseased artery. In all cases, the delivery system was based on the dynamic expansion of a polyurethane balloon under applied internal pressure. Results showed that the expansion is mainly governed by the design, in particular open-cell design (e.g. Endeavor) tends to have greater expansion than closed-cell design (e.g. Cypher). Dogboning effect was strong for slotted tube design (e.g. Palmaz-Schatz) but reduced significantly for sinusoidal design (e.g. Cypher). Under the same pressure, the maximum von Mises stress in the stent was higher for the open-cell designs and located mostly at the inner corners of each cell. For given deformation, stents made of Co-Cr alloys tend to experience higher stress level than those made of stainless steels, mainly due to the difference in material properties. For artery-plaque system, the maximum stress occurred on the stenosis and dogboning led to stress concentration at the ends of the plaque. The drug eluting coating affected the stent expansion by reducing the recoiling phenomenon considerably, but also raised the stress level on the stent due to property mismatch.

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

2013-07-01

320

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

E-print Network

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

Paris-Sud XI, Université de

321

Design and Construction of Field Reversed Configuration Plasma Chamber for Plasma Material Interaction Studies  

NASA Astrophysics Data System (ADS)

A Field Reversed Configuration (FRC) plasma source was designed and constructed to conduct high energy plasma-materials interaction studies. The purpose of these studies is the development of advanced materials for use in plasma based electric propulsion systems and nuclear fusion containment vessels. Outlined within this thesis is the basic concept of FRC plasmoid creation, an overview of the device design and integration of various diagnostics systems for plasma conditions and characterization, discussion on the variety of material defects resulting from the plasma exposure with methods and tools designed for characterization. Using a Michelson interferometer it was determined that the FRC plasma densities are on the order of ~1021 m-3. A novel dynamic pressure probe was created to measure ion velocities averaging 300 km/s. Compensating flux loop arrays were used to measure magnetic field strength and verify the existence of the FRC plasmoid and when used in combination with density measurements it was determined that the average ion temperatures are ~130 eV. X-ray Photoelectron Spectroscopy (XPS) was employed as a means of characterizing the size and shape of the plasma jet in the sample exposure positions. SEM results from preliminary studies reveal significant morphological changes on plasma facing material surfaces, and use of XRD to elucidate fuel gas-ion implantation strain rates correlated to plasma exposure energies.

Smith, DuWayne L.

322

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

323

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

NASA Astrophysics Data System (ADS)

The introduction of 157 nm as the next optical lithography wavelength has created a need for new soft (polymeric) or hard (quartz) pellicle materials optimized for this wavelength. Materials design and development of ultra transparent fluoropolymers suitable for 157 nm soft pellicle applications has produced a number of promising candidate materials with absorbances below 0.03/micrometer as is necessary to achieve pellicle transmissions above 95%. We have developed 12 families of experimental TeflonAFR (TAFx) materials which have sufficient transparency to produce transmissions above 95%. For the successful fabrication of 157 nm pellicles from these materials, the fluoropolymers must have appropriate physical properties to permit the spin coating of thin polymer films and their lifting and adhesive mounting to pellicle frames, the processes which produce free standing pellicle membranes of micron scale thickness. Relevant physical properties include molecular weight, glass transition temperature, and mechanical strength and toughness. We have successfully developed various of the ultra transparent TAFx polymer families with these physical properties. Upon irradiation these 157 nm pellicle polymers undergo photochemical darkening, which reduces the 157 nm transmission of the material. Measurements of the photochemical darkening rate allow the estimation of the pellicle lifetime corresponding to a 10% drop in 157 nm transmission. Increasing the 157 nm lifetime of fluoropolymers involves simultaneous optimization of the materials, the pellicle and the end use. Similar optimization was essential to achieve the desired radiation durability lifetimes for pellicles successfully developed for use with KrF (248 nm) and ArF (193 nm) lithography.

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

2001-09-01

324

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

NASA Technical Reports Server (NTRS)

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

Scott, Elaine P.; Moncman, Deborah A.

1994-01-01

325

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

SciTech Connect

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

L. C. Cadwallader

2013-01-01

326

Design Features and Capabilities of the First Materials Science Research Rack  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

327

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

328

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

SciTech Connect

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

Trond Bjornard; John Hockert

2011-08-01

329

Space Shuttle Orbiter - Leading edge structural design/analysis and material allowables  

NASA Technical Reports Server (NTRS)

Reinforced Carbon-Carbon (RCC), a structural composite whose development was targeted for the high temperature reentry environments of reusable space vehicles, has successfully demonstrated that capability on the Space Shuttle Orbiter. Unique mechanical properties, particularly at elevated temperatures up to 3000 F, make this material ideally suited for the 'hot' regions of multimission space vehicles. Design allowable characterization testing, full-scale development and qualification testing, and structural analysis techniques will be presented herein that briefly chart the history of the RCC material from infancy to eventual multimission certification for the Orbiter. Included are discussions pertaining to the development of the design allowable data base, manipulation of the test data into usable forms, and the analytical verification process.

Johnson, D. W.; Curry, D. M.; Kelly, R. E.

1986-01-01

330

A review of materials for spectral design coatings in signature management applications  

NASA Astrophysics Data System (ADS)

The current focus in Swedish policy towards national security and high-end technical systems, together with a rapid development in multispectral sensor technology, adds to the utility of developing advanced materials for spectral design in signature management applications. A literature study was performed probing research databases for advancements. Qualitative text analysis was performed using a six-indicator instrument: spectrally selective reflectance; low gloss; low degree of polarization; low infrared emissivity; non-destructive properties in radar and in general controllability of optical properties. Trends are identified and the most interesting materials and coating designs are presented with relevant performance metrics. They are sorted into categories in the order of increasing complexity: pigments and paints, one-dimensional structures, multidimensional structures (including photonic crystals), and lastly biomimic and metamaterials. The military utility of the coatings is assessed qualitatively. The need for developing a framework for assessing the military utility of incrementally increasing the performance of spectrally selective coatings is identified.

Andersson, Kent E.; Škerlind, Christina

2014-10-01

331

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

332

Mechanical Design and Material Budget of the CMS Barrel Pixel Detector  

E-print Network

The Compact Muon Solenoid experiment at the Large Hadron Collider at CERN includes a silicon pixel detector as its innermost component. Its main task is the precise reconstruction of charged particles close to the primary interaction vertex. This paper gives an overview of the mechanical requirements and design choices for the barrel pixel detector. The distribution of material in the detector as well as its description in the Monte Carlo simulation are discussed in detail.

C. Amsler; K. Bösiger; V. Chiochia; W. Erdmann; K. Gabathuler; R. Horisberger; S. König; D. Kotlinski; R. Maier; B. Meier; Hp. Meyer; A. Rizzi; P. Robmann; S. Scherr; A. Schmidt; S. Steiner; S. Streuli

2009-04-30

333

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

Microsoft Academic Search

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

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

1998-01-01

334

The design of the building materials management system based on B\\/S structure  

Microsoft Academic Search

The building materials management system, as a system of electronic business application systems, is mainly designed for medium and small enterprises in the distribution of products. It is a distributed-oriented enterprise sales management system to support supply chain management plans and control systems. The feature of the system is a web-based inventory management system online, using browser\\/server structure, achieving online

Juan Zhang

2011-01-01

335

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

PubMed

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

Caposecco, Andrea; Hickson, Louise; Meyer, Carly

2011-12-01

336

Towards the first-principles design of materials with tailored magnetic properties  

Microsoft Academic Search

An important aspect in the design of materials with tailored magnetic properties is the determination of the key structural and electronic features that control those magnetic properties. Here we will address this issue by presenting first-principles results obtained within the LSDA and LDA+U approximations. In particular, we will discuss the family of molecule-based magnets M(N(CN)_2)2 (M=Mn, Co, Ni, etc.), whose

Jorge Iniguez; Taner Yildirim

2004-01-01

337

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

NASA Technical Reports Server (NTRS)

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

Salem, Jonathan A.; Jenkins, Michael G.

2003-01-01

338

Design of a smart material electro-hydraulic actuator with improved frequency bandwidth  

NASA Astrophysics Data System (ADS)

Smart material electro-hydraulic actuators utilize fluid rectification by one-way valves to convert the small, high-frequency, high-force motions of smart materials such as piezoelectrics and magnetostrictives into useful motions of a hydraulic cylinder. These actuators have potential to replace centralized hydraulic pumps and lines with lightweight, compact, power-by-wire systems. This paper presents the design and testing of an improved actuator system. To increase the frequency bandwidth of operation, a lumped-parameter model is developed and validated based on experimental study of a pump with a performance capacity of 18.4 W. The critical parameters for pump performance are identified and their effect on pump performance assessed. The geometry of the hydraulic manifold that integrates the smart material pump and the output hydraulic cylinder is found to be critical for determining the effective system bandwidth.

Larson, John P.; Dapino, Marcelo J.

2012-04-01

339

Materials effects and design implications of disruptions and off-normal events in ITER  

SciTech Connect

Damage to plasma-facing components (PFCs) and structural materials during abnormal plasma behavior such as hard disruptions, edge-localized modes (ELMs), and vertical displacement events (VDEs) is considered a serious life-limiting concern for these components. The PFCs in the International Thermonuclear Experimental Reactor (ITER), such as the divertor, limiter, and parts of the first wall, will be subjected to high energy deposition during these plasma instabilities. High erosion losses on material surfaces, high temperature rise in structural materials (particularly at the bonding interface), and high heat flux levels and possible burnout of the coolant tubes are critical constraints that severely limit component lifetime and therefore degrade reactor performance, safety, and economics. Recently developed computer models and simulation experiments are being used to evaluate various damage to PFCs during the abnormal events. The design implications of plasma-facing and nearby components are discussed, and recommendations are made to mitigate the effects of these events.

Hassanein, A. [Argonne National Lab., IL (United States); Federici, G. [ITER Garching Joint Central Team (Germany); Konkashbaev, I.; Zhitlukhin, A. [Troitsk Inst. for Innovation and Fusion Research (Russian Federation); Litunovsky, V. [Efremov Scientific Research Inst., St. Petersburg (Russian Federation)

1997-08-01

340

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

PubMed

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

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

2014-06-01

341

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

342

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

SciTech Connect

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

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

1995-11-01

343

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

344

Design rules for charge-transport efficient host materials for phosphorescent organic light-emitting diodes.  

PubMed

The use of blue phosphorescent emitters in organic light-emitting diodes (OLEDs) imposes demanding requirements on a host material. Among these are large triplet energies, the alignment of levels with respect to the emitter, the ability to form and sustain amorphous order, material processability, and an adequate charge carrier mobility. A possible design strategy is to choose a ?-conjugated core with a high triplet level and to fulfill the other requirements by using suitable substituents. Bulky substituents, however, induce large spatial separations between conjugated cores, can substantially reduce intermolecular electronic couplings, and decrease the charge mobility of the host. In this work we analyze charge transport in amorphous 2,8-bis(triphenylsilyl)dibenzofuran, an electron-transporting material synthesized to serve as a host in deep-blue OLEDs. We show that mesomeric effects delocalize the frontier orbitals over the substituents recovering strong electronic couplings and lowering reorganization energies, especially for electrons, while keeping energetic disorder small. Admittance spectroscopy measurements reveal that the material has indeed a high electron mobility and a small Poole-Frenkel slope, supporting our conclusions. By linking electronic structure, molecular packing, and mobility, we provide a pathway to the rational design of hosts with high charge mobilities. PMID:22845011

May, Falk; Al-Helwi, Mustapha; Baumeier, Björn; Kowalsky, Wolfgang; Fuchs, Evelyn; Lennartz, Christian; Andrienko, Denis

2012-08-22

345

Recycling issues facing target and RTL materials of inertial fusion designs  

NASA Astrophysics Data System (ADS)

Designers of heavy ion (HI) and Z-pinch inertial fusion power plants have explored the potential of recycling the target and recyclable transmission line (RTL) materials as an alternate option to disposal in a geological repository. This work represents the first time a comprehensive recycling assessment was performed on both machines with an exact pulse history. Our results offer two divergent conclusions on the recycling issue. For the HI concept, target recycling is not a "must" requirement and the preferred option is the one-shot use scenario as target materials represent a small waste stream, less than 1% of the total nuclear island waste. We recommend using low-cost hohlraum materials once-through and then disposing of them instead of recycling expensive materials such as Au and Gd. On the contrary, RTL recycling is a "must" requirement for the Z-pinch concept in order to minimize the RTL inventory and enhance the economics. The RTLs meet the low level waste and recycling dose requirements with a wide margin when recycled for the entire plant life even without a cooling period. While recycling offers advantages to the Z-pinch system, it adds complexity and cost to the HI designs.

El-Guebaly, L.; Wilson, P.; Sawan, M.; Henderson, D.; Varuttamaseni, A.

2005-05-01

346

Design, materials and R&D issues of innovative thermal contact joints for high heat flux applications  

Microsoft Academic Search

Plasma facing components in fusion machines are designed with a layer of sacrificial armour material facing the plasma and a high-conductivity material in contact with the coolant. One of the most critical issues associated with making the proposed design concept work, from a power handling point of view, is achieving the necessary contact conductance between the armour and the heat

G Federici; R Matera; S Chiocchio; J Dietz; G Janeschitz; D Driemeyer; J Haines; M. S Tillack; M Ulrickson

1995-01-01

347

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

ERIC Educational Resources Information Center

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

Bursal, Murat; Yigit, Nevzat

2012-01-01

348

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

SciTech Connect

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

NONE

1995-07-14

349

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

350

Spatial and temporal laser pulse design for material processing on ultrafast scales  

NASA Astrophysics Data System (ADS)

The spatio-temporal design of ultrafast laser excitation can have a determinant influence on the physical and engineering aspects of laser-matter interactions, with the potential of upgrading laser processing effects. Energy relaxation channels can be synergetically stimulated as the energy delivery rate is synchronized with the material response on ps timescales. Experimental and theoretical loops based on the temporal design of laser irradiation and rapid monitoring of irradiation effects are, therefore, able to predict and determine ideal optimal laser pulse forms for specific ablation objectives. We illustrate this with examples on manipulating the thermodynamic relaxation pathways impacting the ablation products and nanostructuring of bulk and surfaces using longer pulse envelopes. Some of the potential control factors will be pointed out. At the same time the spatial character can dramatically influence the development of laser interaction. We discuss spatial beam engineering examples such as parallel and non-diffractive approaches designed for high-throughput, high-accuracy processing events.

Stoian, R.; Colombier, J. P.; Mauclair, C.; Cheng, G.; Bhuyan, M. K.; Velpula, P. K.; Srisungsitthisunti, P.

2014-01-01

351

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

NASA Astrophysics Data System (ADS)

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

Kakeshita, Tomoyuki

2009-07-01

352

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

353

Journal of Materials Education Vol. 24 (4-6): 231-236 (2002) AN UNDERGRADUATE CAPSTONE SUBJECT IN DESIGN AND  

E-print Network

IN DESIGN AND PROCESSING David Roylance Department of Materials Science and Engineering, Massachusetts worked to increase the number and quality of topics oriented toward design, processing, and real.082) is a notable example of this, in which student teams conceive, design and defend the fabrication of a device

Roylance, David

354

Computational Materials Design for High Efficiency Photovoltaic Solar Cells and Transparent Conducting Sulfides  

NASA Astrophysics Data System (ADS)

Based on the first-principles electronic structure calculations we propose computational materials design for high efficiency and low price (In free) solar cell materials based on CuInSe2. Firstly, to avoid the use of In, we try to substitute In by Zn and Sn, or by Ga. The electronic structure calculations are performed by using the KKR-CPA method. To calculate band gap energy correctly, we use self interaction corrections proposed by Filippetti et al. It is found that the direct band gap does not collapse and there appears no deep impurity state in the gap, thus it should be possible to avoid In without any deterioration of photovoltaic effect. From the calculations of mixing energy, we predict that the present system favors the spinodal decomposition and we can expect the formation of nano-wire by two dimensional spinodal nano-decomposition. When the nano-wires are formed, we can expect Type 2 band alignment between host material and the nano-wires. Due to this band alignment, efficient electron hole separation is expected leading to highly efficient photovoltaic effect. As an extension of the present design, we also propose a new class of n-type and p-type transparent conducting sulfides with the negative activation energy for the application of high-efficiency photovoltaic solar-cells.

Katayama-Yoshida, Hiroshi; Tani, Yoshimasa; Sato, Kazunori

2011-03-01

355

A computational framework for the optimal design of morphing processes in locally activated smart material structures  

NASA Astrophysics Data System (ADS)

A proof-of-concept study is presented for a strategy to obtain maximally efficient and accurate morphing structures composed of active materials such as shape memory polymers (SMP) through synchronization of adaptable and localized activation and actuation. The work focuses on structures or structural components entirely composed of thermo-responsive SMP, and particularly utilizes the ability of such materials to display controllable variable stiffness. The study presents and employs a computational inverse mechanics approach that combines a computational representation of the SMP thermo-mechanical behavior with a nonlinear optimization algorithm to determine location, magnitude and sequencing of the activation and actuation to obtain a desired shape change subject to design objectives such as prevention of damage. Two numerical examples are presented in which the synchronization of the activation and actuation and the location of activation excitation were optimized with respect to the combined thermal and mechanical energy for design concepts in morphing skeletal structural components. In all cases the concept of localized activation along with the optimal design strategy were able to produce far more energy efficient morphing structures and more accurately reach the desired shape change in comparison to traditional methods that require complete structural activation prior to actuation.

Wang, Shuang; Brigham, John C.

2012-10-01

356

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

SciTech Connect

The Nuclear Materials Storage Facility (NMSF) at the Los Alamos National Laboratory (LANL) was a Fiscal Year (FY) 1984 line-item project completed in 1987 that has never been operated because of major design and construction deficiencies. This renovation project, which will correct those deficiencies and allow operation of the facility, is proposed as an FY 97 line item. The mission of the project is to provide centralized intermediate and long-term storage of special nuclear materials (SNM) associated with defined LANL programmatic missions and to establish a centralized SNM shipping and receiving location for Technical Area (TA)-55 at LANL. Based on current projections, existing storage space for SNM at other locations at LANL will be loaded to capacity by approximately 2002. This will adversely affect LANUs ability to meet its mission requirements in the future. The affected missions include LANL`s weapons research, development, and testing (WRD&T) program; special materials recovery; stockpile survelliance/evaluation; advanced fuels and heat sources development and production; and safe, secure storage of existing nuclear materials inventories. The problem is further exacerbated by LANL`s inability to ship any materials offsite because of the lack of receiver sites for mate rial and regulatory issues. Correction of the current deficiencies and enhancement of the facility will provide centralized storage close to a nuclear materials processing facility. The project will enable long-term, cost-effective storage in a secure environment with reduced radiation exposure to workers, and eliminate potential exposures to the public. This report is organized according to the sections and subsections outlined by Attachment III-2 of DOE Document AL 4700.1, Project Management System. It is organized into seven parts. This document, Part VII - Estimate Data, contains the project cost estimate information.

NONE

1995-07-14

357

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

358

Geomechanical Modeling to Predict Wellbore Stresses and Strains for the Design of Wellbore Seal Repair Materials  

NASA Astrophysics Data System (ADS)

A critical aspect of designing effective wellbore seal repair materials is predicting thermo-mechanical perturbations in local stress that can compromise seal integrity. For the DOE-NETL project 'Wellbore Seal Repair Using Nanocomposite Materials,' we are especially interested in the stress-strain history of abandoned wells, as well as changes in local pressure, stress, and temperature conditions that accompany carbon dioxide injection or brine extraction. Building on existing thermo-hydro-mechanical (THM) finite element modeling of wellbore casings subject to significant tensile and shear loads, we advance a conceptual and numerical methodology to assess responses of annulus cement and casing. Bench-scale models complement bench-top experiments of an integrated seal system in an idealized scaled wellbore mock-up being used to test candidate seal repair materials. Field scale models use the stratigraphy from a pilot CO2 injection operation to estimate the necessary mechanical properties needed for a successful repair material. We report on approaches used for adapting existing wellbore models and share preliminary results of field scale models. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND Number: 2013-6241A.

Gomez, S. P.; Sobolik, S. R.; Matteo, E. N.; Dewers, T. A.; Taha, M. R.; Stormont, J. C.

2013-12-01

359

Reactive self-tracking solar concentrators: concept, design, and initial materials characterization.  

PubMed

Étendue limits angular acceptance of high-concentration photovoltaic systems and imposes precise two-axis mechanical tracking. We show how a planar micro-optic solar concentrator incorporating a waveguide cladding with a nonlinear optical response to sunlight can reduce mechanical tracking requirements. Optical system designs quantify the required response: a large, slow, and localized increase in index of refraction. We describe one candidate materials system: a suspension of high-index particles in a low-index fluid combined with a localized space-charge field to increase particle density and average index. Preliminary experiments demonstrate an index change of aqueous polystyrene nanoparticles in response to a low voltage signal and imply larger responses with optimized nanofluidic materials. PMID:22410987

Baker, Katherine A; Karp, Jason H; Tremblay, Eric J; Hallas, Justin M; Ford, Joseph E

2012-03-10

360

Material compatibility issues in EU fusion fuel cycle R&D and design  

NASA Astrophysics Data System (ADS)

Many material selections for fusion Fuel Cycle systems are determined by the properties of tritium, including its behaviour as a hydrogen isotope, and its decay product, 3He. Within the EU R&D program, the following issues related to tritium service have been addressed. The mechanical integrity and longevity of the sorbent/bonding agent/substrate system used for cryosorption pumping have been extensively tested under tritium exposure. Extended testing of palladium/silver membranes used for separation of elemental hydrogens from impurities has been carried out to confirm longevity in tritium service. For all high temperature (˜150 °C) components, tritium permeation through primary containments must be confined by outer (low temperature) jackets, and designs have been developed to achieve this. For wetproof catalysts and solid polymer electrolysers used for water detritiation, tests are in progress to determine the operating life. Testing of the ITER reference tritium storage getter material is under way.

Murdoch, D. K.; Cristescu, I.; Day, C.; Glugla, M.; Lässer, R.; Mack, A.

2007-08-01

361

System Design and New Materials for Reversible, Solid-Oxide, High Temperature Steam Electrolysis  

SciTech Connect

High temperature solid oxide electrolysis cells (SOECs) offer high electrical efficiency and a potential path to large scale hydrogen production. Solid oxide technology is capable of both power generation and hydrogen production. That makes it possible for the development of a reversible solid-oxide system that can respond to market conditions to produce electricity or hydrogen on demand. New high-temperature electrolyzer cell materials are needed to enable cost-effective hydrogen production system designs based on reversible steam electrolysis. Two test methods were established for the eventual development of the reversible, durable electrode materials: the button cell test and the oxygen electrode test. The button cell test is capable of evaluating the performance and degradation of full solid oxide cells with dual atmosphere of air and hydrogen-steam. The oxygen electrode test is capable of isolating the performance and degradation of the oxygen electrode. It has higher throughput and sensitivity than the button cell test.

Ruud, J.A.

2007-12-20

362

Magnesium alloys as implant materials--principles of property design for Mg-RE alloys.  

PubMed

Magnesium alloys have attracted increasing interest in the past years due to their potential as implant materials. This interest is based on the fact that magnesium and its alloys are degradable during their time of service in the human body. Moreover magnesium alloys offer a property profile that is very close or even similar to that of human bone. The chemical composition triggers the resulting microstructure and features of degradation. In addition, the entire manufacturing route has an influence on the morphology of the microstructure after processing. Therefore the composition and the manufacturing route have to be chosen carefully with regard to the requirements of an application. This paper discusses the influence of composition and heat treatments on the microstructure, mechanical properties and corrosion behaviour of cast Mg-Gd alloys. Recommendations are given for the design of future degradable magnesium based implant materials. PMID:19788945

Hort, N; Huang, Y; Fechner, D; Störmer, M; Blawert, C; Witte, F; Vogt, C; Drücker, H; Willumeit, R; Kainer, K U; Feyerabend, F

2010-05-01

363

Design of a Protection Thermal Energy Storage Using Phase Change Material Coupled to a Solar Receiver  

NASA Astrophysics Data System (ADS)

Thermal Energy Storage (TES) is the key for a stable electricity production in future Concentrated Solar Power (CSP) plants. This work presents a study on the thermal protection of the central receiver of CSP plant using a tower which is subject to considerable thermal stresses in case of cloudy events. The very high temperatures, 800 °C at design point, impose the use of special materials which are able to resist at high temperature and high mechanical constraints and high level of concentrated solar flux. In this paper we investigate a TES coupling a metallic matrix drilled with tubes of Phase Change Material (PCM) in order to store a large amount of thermal energy and release it in a short time. A numerical model is developed to optimize the arrangement of tubes into the TES. Then a methodology is given, based from the need in terms of thermal capacity, in order to help the choice of the geometry.

Verdier, D.; Falcoz, Q.; Ferrière, A.

2014-12-01

364

Molecular design and ordering effects in ?-functional materials for transistor and solar cell applications.  

PubMed

Organic electronics are broadly anticipated to impact the development of flexible thin-film device technologies. Among these, solution-processable ?-conjugated polymers and small molecules are proving particularly promising in field-effect transistors and bulk heterojunction solar cells. This Perspective analyzes some of the most exciting strategies recently suggested in the design and structural organization of ?-functional materials for transistor and solar cell applications. Emphasis is placed on the interplay between molecular structure, self-assembling properties, nanoscale and mesoscale ordering, and device efficiency parameters. A critical look at the various approaches used to optimize both materials and device performance is provided to assist in the identification of new directions and further advances. PMID:21999757

Beaujuge, Pierre M; Fréchet, Jean M J

2011-12-21

365

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

SciTech Connect

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

Polikarpov, Evgueni; Padmaperuma, Asanga B.

2012-04-01

366

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

SciTech Connect

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

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

1983-11-01

367

Design and Implementation of a Facility for Discovering New Scintillator Materials  

SciTech Connect

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

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

2008-04-25

368

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

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

369

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

Microsoft Academic Search

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

H. Katayama-Yoshida; K. Sato

2003-01-01

370

Design of conformal lens by drilling holes materials using quasi-conformal transformation optics.  

PubMed

In this paper, based on quasi-conformal transformation optics, a 3D conformal lens made of isotropic and non-resonant metamaterial is designed, which can make a cylindrical conformal array behave similarly to a uniform linear array. After discussion and simplification in the two-dimensional model, we realize the proposed lens by utilizing drilling-hole material in the three-dimensional structure. The ring-like shape and forward-only radiation make it possible to equip the lens on a cylindrical device. PMID:25401578

Li, Shouliang; Zhang, Zhan; Wang, Junhong; He, Xianshi

2014-10-20

371

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

SciTech Connect

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

Luskin, Mitchell [University of Minnesota

2014-03-12

372

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

SciTech Connect

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

Thackeray, M.; Chemical Sciences and Engineering Division

2007-01-01

373

Applications of molecular modeling to the design and characterization of materials  

NASA Astrophysics Data System (ADS)

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

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

374

Thickness determination in textile material design: dynamic modeling and numerical algorithms  

NASA Astrophysics Data System (ADS)

Textile material design is of paramount importance in the study of functional clothing design. It is therefore important to determine the dynamic heat and moisture transfer characteristics in the human body-clothing-environment system, which directly determine the heat-moisture comfort level of the human body. Based on a model of dynamic heat and moisture transfer with condensation in porous fabric at low temperature, this paper presents a new inverse problem of textile thickness determination (IPTTD). Adopting the idea of the least-squares method, we formulate the IPTTD into a function minimization problem. By means of the finite-difference method, quasi-solution method and direct search method for one-dimensional minimization problems, we construct iterative algorithms of the approximated solution for the IPTTD. Numerical simulation results validate the formulation of the IPTTD and demonstrate the effectiveness of the proposed numerical algorithms.

Xu, Dinghua; Ge, Meibao

2012-03-01

375

An inverse problem of thickness design for bilayer textile materials under low temperature  

NASA Astrophysics Data System (ADS)

The human heat-moisture-comfort level is mainly determined by heat and moisture transfer characteristics in clothing. With respect to the model of steady-state heat and moisture transfer through parallel pore textiles, we propose an inverse problem of thickness design for bilayer textile material under low temperature in this paper. Adopting the idea of regularization method, we formulate the inverse problem solving into a function minimization problem. Combining the finite difference method for ordinary differential equations with direct search method of one-dimensional minimization problems, we derive three kinds of iteration algorithms of regularized solution for the inverse problem of thickness design. Numerical simulation is achieved to verify the efficiency of proposed methods.

Xu, Dinghua; Cheng, Jianxin; Chen, Yuanbo; Ge, Meibao

2011-04-01

376

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

SciTech Connect

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

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

2011-07-01

377

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

NASA Astrophysics Data System (ADS)

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 the same time to some extent just a few atomic layers sometimes determine the properties of the material, as is well known in semiconductor and other thin film technologies. Therefore, a detailed understanding of the materials properties at the atomic scale becomes more and more important. In addition many high tech materials have to be of high purity or selective dopant concentrations have to be adjusted to fulfill the desired functionality. Modern materials developments successfully use computational materials science to achieve that goal. Improved software tools and continuously growing computational power allow us to predict macroscopic properties of materials on the basis of microscopic/atomic ab initio simulation approaches. At Schott, special materials, in particular glasses and glass ceramics, are produced for a variety of applications. For a glass ceramic all the above mentioned difficulties for materials development arise. The properties of a glass ceramic are determined by the interplay of crystalline phases embedded in an amorphous glass matrix. For materials development the understanding of crystal structures and their properties, surfaces and interface phenomena, and amorphous systems are necessary, likewise. Each by itself is already a challenging problem. Many crystal phases that are grown within the glass matrix do not exist as single crystals or are difficult to grow in reasonable amounts for experimental investigations. The only way to obtain the properties of these crystalline phases is through 'ab initio' simulations in the computer. In this presentation results of density functional theory (DFT) calculations of various crystal structures, mainly oxides, are discussed. The focus is on the thermomechanical and optical properties. We present elastic properties and the anisotropic Young's modulus for spinel structures, pyrosilicates and further oxides like rutile. Their influence on the stiffness of a resulting glass ceramic is discussed. The thermal expansion of glass ceramics is an important feature and is strongly dependent on the coefficient of thermal expansion (CTE) of the crystalline phases. For selective oxides the calculation of the CTE in the harmonic approximation is presented and a comparison with experiments is given. Optical devices for microlithography use CaF2 crystal as a lens material. The optical properties and the influence of certain impurities in CaF2 are crucial for the performance of such devices. 'Ab initio' simulation helps us here to estimate the formation of defects and color centers. Local density approximation screened exchange calculations for the optical properties of CaF2 are presented as well as DFT simulation results for impurities and defects.

Mannstadt, Wolfgang

2008-02-01

378

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

SciTech Connect

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

Price, M. A.; Murphy, A.; Butterfield, J.; McCool, R.; Fleck, R. [CEIAT, School of Mechanical and Aerospace Engineering, Queens University, Belfast (United Kingdom)

2011-05-04

379

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

380

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

NASA Astrophysics Data System (ADS)

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

Kumar, Atul

381

Design of a high pulse repitition frequency carbon dioxide laser for processing high damage threshold materials  

NASA Astrophysics Data System (ADS)

The absence of an applications led design philosophy has compromised both the development of laser source technology and its effective implementation into manufacturing technology in particular. For example, CO2 lasers are still incapable of processing classes of refractory and non-ferrous metals. Whilst the scope of this paper is restricted to high power CO2 lasers; the design methodology reported herein is applicable to source technology in general, which when exploited, will effect an expansion of applications. The CO2 laser operational envelope should not only be expanded to incorporate high damage threshold materials but also offer a greater degree of controllability. By a combination of modelling and experimentation the requisite beam characteristics, at the workpiece, were determined then utilised to design the Laser Manufacturing System. The design of sub-system elements was achieved by a combination of experimentation and simulation which benefited from a comprehensive set of software tools. By linking these tools the physical processes in the laser - electron processes in the plasma, the history of photons in the resonator, etc. - can be related, in a detailed model, to the heating mechanisms in the workpiece.

Chatwin, Christopher R.; McDonald, Donald W.; Scott, Brian F.

1989-07-01

382

Design of Low Elastic Modulus Ti-Nb-Zr Alloys for Implant Materials  

NASA Astrophysics Data System (ADS)

Titanium alloys are expected to be much more widely used for hard tissue implant materials due to their superior biocompatibility and high corrosion. However, the larger Young's modulus of present titanium alloys always leads to stress shielding and harmful effects on human bones and results in premature failure of the implant. Recently a d-electron alloy design method has been proposed to design low elastic modulus titanium alloys and achieve some actual results. In this paper, a series of the Ti-Nb-Zr alloys has been designed with the d-electron alloy design method, and the phase structure, lattice parameter and elastic modulus have been investigated. The results show that with the increase of /line {Bo} and /line {Md} , the lattice parameters of these alloys increase monotonously with the single phase structure of bcc ? phase. The maximum increment reaches 4.5% compared with that of matrix ? phase. As the /line {Bo} and /line {Md} increase up further, the phase structure begins to change from bcc ? phase to hcp ? phase. Correspondingly the elastic modulus decreases first and then increase, from 96.8 GPa to 67.4 GPa, and then to 83.2GPa with the increase of /line {Bo} and /line {Md} . The lattice parameter and phase structure both exhibit significant influences on the elastic modulus of these alloys.

Song, Xiping; You, Li; Zhang, Bei; Song, Anna

2011-06-01

383

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

SciTech Connect

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

Rennich, M.J. [comp.

1996-12-01

384

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

NASA Technical Reports Server (NTRS)

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

Estrada, Hector; Smeltzer, Stanley S., III

1999-01-01

385

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

PubMed Central

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

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

2008-01-01

386

Performance improvement in amorphous silicon based uncooled microbolometers through pixel design and materials development  

NASA Astrophysics Data System (ADS)

Uncooled amorphous silicon microbolometers have been established as a field-worthy technology for a broad range of applications where performance and form factor are paramount, such as soldier-borne systems. Recent developments in both bolometer materials and pixel design at L-3 in the 17?m pixel node have further advanced the state-of-the-art. Increasing the a-Si material temperature coefficient of resistance (TCR) has the impact of improving NETD sensitivity without increasing thermal time constant (TTC), leading to an improvement in the NETD×TTC product. By tuning the amorphous silicon thin-film microstructure using hydrogen dilution during deposition, films with high TCR have been developed. The electrical properties of these films have been shown to be stable even after thermal cycling to temperatures greater than 300oC enabling wafer-level vacuum packaging currently performed at L-3 to reduce the size and weight of the vacuum packaged unit. Through appropriate selection of conditions during deposition, amorphous silicon of ~3.4% TCR has been integrated into the L-3 microbolometer manufacturing flow. By combining pixel design enhancements with improvements to amorphous silicon thin-film technology, L-3's amorphous silicon microbolometer technology will continue to provide the performance required to meet the needs to tomorrow's war-fighter.

Ajmera, Sameer; Brady, John; Hanson, Charles; Schimert, Tom; Syllaios, A. J.; Taylor, Michael

2011-06-01

387

Design of Bioactive Organic-inorganic Hybrid Materials with Self-setting Ability  

NASA Astrophysics Data System (ADS)

Paste-like materials with ability of self-setting are attractive for bone substitutes, since they can be injected from the small hole with minimized invasion to the patient. Although bone cements which set as apatite are clinically used, there is limitation on clinical applications due to their mechanical properties such as high brittleness and low fracture toughness. To overcome this problem, organic-inorganic hybrids based on a flexible polymer are attractive. We have obtained an idea for design of self-setting hybrids using polyion complex fabricated by ionic interaction of anionic and cationic polymers. We aimed at preparation of organic-inorganic hybrids exhibiting self-setting ability and bioactivity. The liquid component was prepared from cationic chitosan aqueous solution. The powder component was prepared by mixing various carrageenans with ?-tricalcium phosphate (?-TCP). The obtained cements set within 1 day. Compressive strength showed tendency to increase with increase in ?-TCP content in the powder component. The prepared cements formed the apatite in simulated body fluid within 3 days. Novel self-setting materials based on organic-inorganic hybrid can be designed utilizing ionic interaction of polysaccharide.

Miyazaki, T.; Machida, S.; Morita, Y.; Ishida, E.

2011-10-01

388

Peridynamics as a rigorous coarse-graining of atomistics for multiscale materials design.  

SciTech Connect

This report summarizes activities undertaken during FY08-FY10 for the LDRD Peridynamics as a Rigorous Coarse-Graining of Atomistics for Multiscale Materials Design. The goal of our project was to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. The goal of our project is to develop a coarse-graining of finite temperature molecular dynamics (MD) that successfully transitions from statistical mechanics to continuum mechanics. Our coarse-graining overcomes the intrinsic limitation of coupling atomistics with classical continuum mechanics via the FEM (finite element method), SPH (smoothed particle hydrodynamics), or MPM (material point method); namely, that classical continuum mechanics assumes a local force interaction that is incompatible with the nonlocal force model of atomistic methods. Therefore FEM, SPH, and MPM inherit this limitation. This seemingly innocuous dichotomy has far reaching consequences; for example, classical continuum mechanics cannot resolve the short wavelength behavior associated with atomistics. Other consequences include spurious forces, invalid phonon dispersion relationships, and irreconcilable descriptions/treatments of temperature. We propose a statistically based coarse-graining of atomistics via peridynamics and so develop a first of a kind mesoscopic capability to enable consistent, thermodynamically sound, atomistic-to-continuum (AtC) multiscale material simulation. Peridynamics (PD) is a microcontinuum theory that assumes nonlocal forces for describing long-range material interaction. The force interactions occurring at finite distances are naturally accounted for in PD. Moreover, PDs nonlocal force model is entirely consistent with those used by atomistics methods, in stark contrast to classical continuum mechanics. Hence, PD can be employed for mesoscopic phenomena that are beyond the realms of classical continuum mechanics and atomistic simulations, e.g., molecular dynamics and density functional theory (DFT). The latter two atomistic techniques are handicapped by the onerous length and time scales associated with simulating mesoscopic materials. Simulating such mesoscopic materials is likely to require, and greatly benefit from multiscale simulations coupling DFT, MD, PD, and explicit transient dynamic finite element methods FEM (e.g., Presto). The proposed work fills the gap needed to enable multiscale materials simulations.

Lehoucq, Richard B.; Aidun, John Bahram; Silling, Stewart Andrew; Sears, Mark P.; Kamm, James R.; Parks, Michael L.

2010-09-01

389

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

SciTech Connect

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

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

2013-01-01

390

Mechanics guided design of hybrid laser/waterjet system for machining hard and brittle materials  

NASA Astrophysics Data System (ADS)

The two main objectives of this work is (1) to develop a mathematical model to efficiently capture the fracture behavior of materials undergoing thermal shock and (2) to design and develop a mechanics based hybrid laser/waterjet manufacturing process that will be able to machine hard and brittle materials at higher speeds and with better cut quality. The mathematical model relates the temperature generated during the machining process to the fracture behavior observed during machining. The hybrid manufacturing processes produces a synergetic effect of both laser and waterjet processes and overcomes the disadvantages of both of them. The temperature distribution is obtained from the Green's solution of the Fourier Heat Conduction equation. Uncoupled thermoelastic stresses are obtained from the temperature distribution which in-turn is related to the stress intensity factor/Griffith Energy for Mode I crack growth by Bueckner's weight function approach. This model can also be used to predict fracture behavior for given laser processing conditions. This model can also be used to manipulate transformational stresses that occur during machining of high conductive materials. This model can be easily extended to many multi-physics problems involving thermo-elastic behavior.

Kalyanasundaram, Dinesh

391

Small optical gap molecules and polymers: using theory to design more efficient materials for organic photovoltaics.  

PubMed

Recent improvements in the power conversion efficiencies of organic solar cells have been derived through a combination of new materials, processing, and device designs. A key factor has also been quantum-chemical studies that have led to a better understanding not only of the intrinsic electronic and optical properties of the materials but also of the physical processes that take place during the photovoltaic effect. In this chapter we review some recent quantum-chemical investigations of donor-acceptor copolymers, systems that have found wide use as the primary absorbing and hole-transport materials in bulk-heterojunction solar cells. We underline a number of current limitations with regard to available electronic structure methods and in terms of the understanding of the processes involved in solar cell operation. We conclude with a brief outlook that discusses the need to develop multiscale simulation methods that combine quantum-chemical techniques with large-scale classically-based simulations to provide a more complete picture. PMID:23780413

Risko, Chad; Brédas, Jean-Luc

2014-01-01

392

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

SciTech Connect

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

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

1998-12-31

393

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

NASA Technical Reports Server (NTRS)

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

Bowman, Cheryl L.

2013-01-01

394

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

PubMed Central

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

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

2012-01-01

395

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

396

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

NSDL National Science Digital Library

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

Currie, Eddie

397

Polymer and Material Design for Lithography From 50 nm Node to the sub-16 nm Node  

NASA Astrophysics Data System (ADS)

Microlithography is one of the technologies which enabled the Information Age. Developing at the intersection of optical physics, polymer science and photochemistry, the need for ever smaller high fidelity patterns to build integrated circuits is currently pushing the technology evolution from 193 nm immersion lithography to extreme ultraviolet lithography (13.5 nm) to alternate patterning technologies such as directed self assembly (DSA) of block copolymers. Essential to the success of this progression is a rapid application of new concepts and materials in polymer science. We will discuss the requirements for 193 immersion lithography and how advanced acrylic random polymers are being designed with chemical amplification functionality to meet these needs. The special requirements of a water immersion lithography led to the invention and rapid commercial application of surface assembled embedded barrier layer polymers. Design of polymers for EUV lithography is having to respond to much different challenges, prominent being the dearth of photons in the exposure step, and the other being how to maximize the efficiency of photoacid production. In parallel, alternative lithographic approaches are being developed using directed self assembly of block copolymers which realize pattern frequency multiplication. We will update with our progress in the applications of polymers designed for DSA.

Trefonas, Peter

2012-02-01

398

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

SciTech Connect

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

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

1998-08-01

399

Modeling the Thermal Conductivity of Pure and Mixed Heavy n Alkanes Suitable for the Design of Phase Change Materials  

Microsoft Academic Search

Recent interest in the use of paraffin waxes is related to energy management provided by phase change materials (PCMs) where a tunable melting temperature range is used to store or release latent heat by means of the solid–liquid phase change. Thermal conductivity is an essential property for the correct design of these new materials, with applications as different as household

F. Paradela; A. J. Queimada; I. M. Marrucho; C. P. Neto; J. A. P. Coutinho

2005-01-01

400

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

E-print Network

WELDING & MATERIALS TECHNOLOGY The occupational endorsement certification in welding and materials technology is designed for beginning students who want to learn to cut and weld, as well as students seeking more advanced courses who would like to take their welding skills further. Our program emphasizes

Ickert-Bond, Steffi

401

DESIGN AND DEPLOYMENT OF A MOBILE SENSOR NETWORK FOR THE SURVEILLANCE OF NUCLEAR MATERIALS IN METROPOLITAN AREAS  

E-print Network

to sophisticated technologies and materials. Among all the threats, nuclear attacks are arguably the most, Latent Models, Cluster Detection, Scan Statistics Abstract--Nuclear attacks are among the mostDESIGN AND DEPLOYMENT OF A MOBILE SENSOR NETWORK FOR THE SURVEILLANCE OF NUCLEAR MATERIALS

402

Curriculum Materials as a Vehicle for Innovation: a case study of the Nuffield Design and Technology Project  

Microsoft Academic Search

Prior to the advent of the National Curriculum in England and Wales, the production of teaching materials was an established vehicle for curriculum change. The Nuffield Design and Technology Project recently published extensive materials which enlarge upon the National Curriculum. This paper presents an investigation based on case studies of two teachers in separate schools, each using Nuffield publications with

Nick Givens

2000-01-01

403

The effect of material properties and tooling design on deformation and fracture during equal channel angular extrusion  

Microsoft Academic Search

The effects of material constitutive behavior, tooling design, and friction conditions on metal flow, stress fields, and the tendency for tensile fracture during equal channel angular extrusion (ECAE) were established using a finite element modeling (FEM) technique. Three different material behaviors, typical of those encountered during cold and hot working, were investigated; these comprised (i) strain hardening, (ii) rigid, perfectly

S. L. Semiatin; D. P. DeLo; E. B. Shell

2000-01-01

404

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

ERIC Educational Resources Information Center

Many educational researchers have investigated how best to support conceptual learning in science education. In this study, the aim was to design learning materials using Physlets, small computer simulations, and to evaluate the effectiveness of these materials in supporting conceptual learning in secondary school physics. Students were taught in…

Ülen, Simon; Cagran, Branka; Slavinec, Mitja; Gerlic, Ivan

2014-01-01

405

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

NASA Astrophysics Data System (ADS)

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

Monti, Riccardo; Gasbarri, Paolo; Lecci, Umberto

2012-12-01

406

The design and evaluation of high barrier performance organic BARC material  

NASA Astrophysics Data System (ADS)

The pattern shrinkage of semiconductor devices has been achieved by moving to shorter and shorter wavelengths in the optical lithography technologies. According to the ITRS, it is estimated that this trend will be continued through advanced lithography techniques such as Hyper NA immersion lithography, double patterning technique and EUV lithography. In the future, photo-resist film thickness requirements will approach 100 nm or less to achieve suitable aspect ratios. Therefore, organic bottom anti-reflective coating (BARC) film thicknesses must also be reduced from the viewpoint of the etching process. Due to these design changes, the performance of BARCs, especially photo-resist profile control and maintaining enough of a lithography process margin at the critical CD has become more crucial. Problem of photo-resist profiles, such as missing holes or scumming for contact holes (C/H) and footing in line-space (L/S) patterns by contamination from the substrate are known as resist poisoning. In order to prevent this issue, BARC films need to have not only reflection control properties but they also need to capable of contamination or poison blocking. Therefore, barrier properties to prevent contamination or poisoning should be included in the design of these new BARC materials. For developing these BARC that are designed to have both barrier properties and reflection control at around 30 nm thickness, we investigated their performance by evaluating both the chemical and physical property of BARC film. The design of these barrier films and details of evaluation experiments are discussed in this paper.

Ishida, Tomohisa; Sakamoto, Rikimaru; Hiroi, Yoshiomi; Sakaida, Yasushi; Hamada, Takahiro

2008-03-01

407

Web-Based Tools for Designing and Developing Teaching Materials for Integration of Information Technology into Instruction  

ERIC Educational Resources Information Center

Educational software for teachers is an important, yet usually ignored, link for integrating information technology into classroom instruction. This study builds a web-based teaching material design and development system. The process in the system is divided into four stages, analysis, design, development, and practice. Eight junior high school…

Chang, Kuo-En; Sung, Yao-Ting; Hou, Huei-Tse

2006-01-01

408

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

Federal Register 2010, 2011, 2012, 2013

...ER-FRL-8991-4] Notice of Intent: Designation of an Ocean Dredged Material Disposal Site (ODMDS) Off the Mouth of the...action alternative is defined as not designating an additional ocean disposal site. The existing Jacksonville ODMDS would...

2010-07-09

409

Design of Inserts for Split-Hopkinson Pressure Bar Testing of Low Strain-to-Failure Materials  

E-print Network

Design of Inserts for Split-Hopkinson Pressure Bar Testing of Low Strain-to-Failure Materials G # Society for Experimental Mechanics 2008 Abstract In the present study a new insert design is presented the Split-Hopkinson Pressure Bar (SHPB) apparatus. Finite element-based simulations are conducted to better

Rollins, Andrew M.

410

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

NASA Technical Reports Server (NTRS)

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

1996-01-01

411

Enzymatically controlled material design with casein - from defined films to localized deposition of particles.  

PubMed

A new concept for deposition and material design of coatings from biological compounds is presented. An enzymatic reaction triggers the specific coagulation of particles on a support surface. The first examined model system is casein and is based on the natural rennet-reaction as applied in the process of cheese making. The aspartic protease chymosin is immobilized on a support surface and cleaves the hydrophilic parts of the casein micelles, inducing deposition. The concept allows for a high level of control over film characteristics and enables the formation of site-specific film structures. The variability rages from formation of casein films with several micrometers film thickness to the targeted deposition of casein micelles. PMID:25456052

Strube, Oliver I; Rüdiger, Arne A; Bremser, Wolfgang

2014-10-20

412

Design and synthesis of a new layered thermoelectric material LaPbBiS3O.  

PubMed

A new quinary oxysulfide LaPbBiS3O was designed and successfully synthesized via a solid-state reaction in a sealed evacuated quartz tube. This material, composed of stacked NaCl-like [M4S6] (where M = Pb, Bi) layers and fluorite-type [La2O2] layers, crystallizes in the tetragonal space group P4/nmm with a = 4.0982(1) Å, c = 19.7754(6) Å, and Z = 2. Electrical resistivity and Hall effect measurements demonstrate that it is a narrow gap semiconductor with an activation energy of ?17 meV. The thermopower and the figure of merit at room temperature were measured to be -52 ?V/K and 0.23, respectively, which makes LaPbBiS3O and its derivatives be promising for thermoelectric applications. PMID:25272272

Sun, Yun-Lei; Ablimit, Abduweli; Zhai, Hui-Fei; Bao, Jin-Ke; Tang, Zhang-Tu; Wang, Xin-Bo; Wang, Nan-Lin; Feng, Chun-Mu; Cao, Guang-Han

2014-10-20

413

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

PubMed

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

Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

2014-01-01

414

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

NSDL National Science Digital Library

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

Rais-Rohani, Masoud

415

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

NASA Astrophysics Data System (ADS)

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

Gibson, J. Murray

2009-05-01

416

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

417

Investigation of lightweight designs and materials for LO2 and LH2 propellant tanks for space vehicles, phase 1  

NASA Technical Reports Server (NTRS)

Design, analysis, and fabrication studies were performed on nonintegral (suspended) tanks using a representative space tug design. The LH2 and LO2 tank concept selection was developed. Tank geometries and support relationships were investigated using tug design propellant inertias and ullage pressures, then compared based on total tug systems effects. The tank combinations which resulted in the maximum payload were selected. Tests were conducted on samples of membrane material which was processed in a manner simulating production tank fabrication operations to determine fabrication effects on the fracture toughness of the tank material. Fracture mechanics analyses were also performed to establish a preliminary set of allowables for initial defects.

1975-01-01

418

Designing an embedded probe for hazardous material shelf-life monitoring  

NASA Astrophysics Data System (ADS)

Navy administrators estimate that hundreds of tons of hazardous material (HAZMAT) are being wastefully discarded due to premature disposal. Currently, HAZMAT items are coded when they are brought into the DoD supply system to indicate their storage lifetime. However, this process has come under criticism for generating shelf life codes that are too conservative and can not account for the varying storage conditions experienced by an individual item. Naturally, a detailed laboratory examination could determine when an time has reached the end of its useful shelf life, but this logistically clumsy approach is rarely undertaken, and thus HAZMAT is wastefully discarded. An ideal inspection method would be fast, reliable and non-invasive. We have investigated the development and use of an inexpensive nondestructive sensor to actively assess the shelf state of a ubiquitous HAZMAT, Silicon Alkyd Haze Gray paint. A simple sensor was designed to measure six features of the paint: ultrasonic velocity and attenuation, electric mobility and polarization and temperature and thermal diffusivity. To simulate the storage environment, an accelerated environmental degradation procedure was implemented to force the paint along realistic and prominent failure modes. During this degradation process, the material was monitored with the sensor and a set of standard laboratory measurement techniques. Pattern recognition techniques were applied to identify key characteristics of the data and to design a classifier to discriminate between different classes of the aged samples. Issues of sensitivity, uniqueness and indeterminacy in the problem were considered. Based on these results, a prototype sensor for shelf life management of hazardous silicon alkyd paint appears to be promising.

Gordon, Grant A.; McClintic, Katherine T.; Holder, A. G.; Babich, Gregory A.

1999-05-01

419

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

NASA Astrophysics Data System (ADS)

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

Deng, Meng

420

Evaluations of candidate encapsulation designs and materials for low-cost silicon photovoltaic arrays  

NASA Technical Reports Server (NTRS)

Three encapsulation designs for silicon photovoltaic arrays based on cells with silk-screened Ag metallization have been evaluated: transparent polymeric coatings over cells laminated between two films or sheets of polymeric materials; cells adhesively bonded to a glass cover with a polymer pottant and a glass or other substrate component. Silicone and acrylic coatings were assessed, together with acrylic sheet, 0.635 mm fiberglass-reinforced polyester sheet, 0.102 mm polycarbonate/acrylic dual-layer film, 0.127 mm fluorocarbon film, soda-lime glass, borosilicate glass, low-iron glass, and several adhesives. The encapsulation materials were characterized by light transmittance measurements, determination of moisture barrier properties and bond strengths, and by the performance of cells before and after encapsulation. Silicon and acrylic coatings provided inadequate protection. Acrylic and fluorocarbon films displayed good weatherability and acceptable optical transmittance. Borosilicate, low-iron and soda-lime-float glasses were found to be acceptable candidate encapsulants for most environments.

Gaines, G. B.; Carmichael, D. C.; Sliemers, F. A.; Brockway, M. C.; Bunk, A. R.; Nance, G. P.

1978-01-01

421

On the Properties of Materials for Designing Filters at Optical Frequencies  

SciTech Connect

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

E. Topsakal; J.L. Volakis

2003-05-05

422

Design of new generation femoral prostheses using functionally graded materials: a finite element analysis.  

PubMed

This study aimed to develop a three-dimensional finite element model of a functionally graded femoral prosthesis. The model consisted of a femoral prosthesis created from functionally graded materials (FGMs), cement, and femur. The hip prosthesis was composed of FGMs made of titanium alloy, chrome-cobalt, and hydroxyapatite at volume fraction gradient exponents of 0, 1, and 5, respectively. The stress was measured on the femoral prosthesis, cement, and femur. Stress on the neck of the femoral prosthesis was not sensitive to the properties of the constituent material. However, stress on the stem and cement decreased proportionally as the volume fraction gradient exponent of the FGM increased. Meanwhile, stress became uniform on the cement mantle layer. In addition, stress on the femur in the proximal part increased and a high surface area of the femoral part was involved in absorbing the stress. As such, the stress-shielding area decreased. The results obtained in this study are significant in the design and longevity of new prosthetic devices because FGMs offer the potential to achieve stress distribution that more closely resembles that of the natural bone in the femur. PMID:23516951

Oshkour, A A; Abu Osman, N A; Yau, Y H; Tarlochan, F; Abas, W A B Wan

2013-01-01

423

Rational design of original materials for the electrocatalytic hydrogenation reactions: concept, preparation, characterization, and theoretical analysis.  

PubMed

Original and versatile new materials for the electrocatalytic hydrogenation of organic compounds were designed. The materials consist of reticulated glassy carbon cathode electrodes in which the modified silica particles (average diameter 40-63 microm) were dynamically circulated. The modification of the silica surface is 2-fold. First, the silica is surface-modified using organic functions such as -OSi(CH3)2(CH2)3OCH2CH-(OH)(CH)2OH (SiO2-Diol), -OSi(CH3)2(CH2)7CH3 (SiO2-C8), and -OSi(CH3)2C6H5 (SiO2-Phenyl). Second, these silica particles were further modified by vapor phase deposition of nickel nanoaggregates (used as sites for hydrogen atoms and electric contacts with the electrode material), which does not destroy or alter the organic functionalization as demonstrated by thermogravimetric analysis-mass spectrometry and Raman, diffuse reflectance IR Fourier transform, and Auger electron spectroscopies. The new concept stems from relative adsorption and desorption properties of the organic molecules and their corresponding reduced products into the organic functionalization of the surface-modified silica. In this work, the electrocatalytic hydrogenation cyclohexanone was used to test the concept. The performances (amount of cyclohexanol vs time of generated electrolysis at constant current) are measured and compared for the various bonded organic functions of the silica surface listed above, along with the unmodified silica particles (but still containing nickel nanoaggregates) and the presence or absence of methanol in solution. The measurements of the adsorption isotherms of cyclohexanone, and the calculations of the interaction energies (MM3 force field) between the chemisorbed organic functions and the substrates, corroborate perfectly the electrocatalysis results. PMID:15248724

St-Pierre, Geneviève; Chagnes, Alexandre; Bouchard, Nicolas-Alexandre; Harvey, Pierre D; Brossard, Louis; Ménard, Hugues

2004-07-20

424

Effect of electrode material and design on sensitivity and selectivity for high temperature impedancemetric NOx sensors  

SciTech Connect

Solid-state electrochemical sensors using two different sensing electrode compositions, gold and strontium-doped lanthanum manganite (LSM), were evaluated for gas phase sensing of NO{sub x} (NO and NO{sub 2}) using an impedance-metric technique. An asymmetric cell design utilizing porous YSZ electrolyte exposed both electrodes to the test gas (i.e., no reference gas). Sensitivity to less than 5 ppm NO and response/recovery times (10-90%) less than 10 s were demonstrated. Using an LSM sensing electrode, virtual identical sensitivity towards NO and NO{sub 2} was obtained, indicating that the equilibrium gas concentration was measured by the sensing electrode. In contrast, for cells employing a gold sensing electrode the NO{sub x} sensitivity varied depending on the cell design: increasing the amount of porous YSZ electrolyte on the sensor surface produced higher NO{sub 2} sensitivity compared to NO. In order to achieve comparable sensitivity for both NO and NO{sub 2}, the cell with the LSM sensing electrode required operation at a lower temperature (575 C) than the cell with the gold sensing electrode (650 C). The role of surface reactions are proposed to explain the differences in NO and NO{sub 2} selectivity using the two different electrode materials.

Woo, L Y; Glass, R S; Novak, R F; Visser, J H

2009-09-23

425

Designing and nanoscale engineering of organic/inorganic electronic materials for organic light-emitting diodes  

NASA Astrophysics Data System (ADS)

Organic light-emitting diodes (OLEDs) have been intensively studied due to their emerging applications in flat panel display technologies. The motivation of the present research has been the desire to (a) explore new routes to OLED functional layers with rigorous control of layer properties; (b) probe the effects of OLED anode-hole transport layer interfacial energetics on charge injection, luminous efficiency; (c) acquire micron-scale multicolor OLED pixels for potential high resolution OLED display application; (d) better understand and further improve charge injection into molecular and macromolecular solids by designing and implementing novel OLED anode materials. In the first part, a spin-coating/siloxane cross-linking approach has been applied to OLED charge transport layers which provides a high throughput route to robust, pinhole-free, adherent thin films with covalently interlinked, glassy structures (Chapter 2). In anode-hole transport layer contact study (Chapter 3), it is shown that integrity of electrode/organic interfacial contact is crucial to the performance and stability of organic light emitting diodes (OLEDs). It is demonstrated that self-assembled or spincoated nm-scale thick silane derived hole transport layer on ITO can effectively prevent de-wetting of the vapor deposited TPD hole transport layers (Chapter 3), leading to significantly enhanced light output (15,000 cd/m2), luminous efficiency (1.2%), and thermal stability (up to 110°C). In applying soft lithography techniques to OLED micro-patterning, we designed and implemented high temperature micro-contact printing, which readily affords pixel features down to 1.0 micron dimensions, and which, by virtue of the length scale-dependent carrier tunneling through SAM structures, affords tenability in luminescence patterns (Chapter 4). To facilitate hole injection at anode side of OLED, MOCVD derived, highly transparent, high work function thin film TCO materials is synthesized and employed as OLED anodes (Chapter 5). Besides exhibiting high electrical conductivities (1000--3300 S/cm) and outstanding optical transparencies (>90%), these TCO films possess unusually high work functions (5.2--6.1 eV vs. 4.7 eV for ITO). OLED devices fabricated with these materials as anodes exhibit electroluminescence performance comparable to or better than ITO-based devices.

Cui, Ji

2001-07-01

426

Design, synthesis and characterization of novel materials with high ionic conductivity  

NASA Astrophysics Data System (ADS)

In this dissertation, the design, synthesis and characterization of several different types of new materials with high ionic conductivity are described. These new materials include Lewis acid-lithium salt complexes, new polymer electrolytes, mixed alkali halides and anhydrous proton conductors. Highly conductive materials were obtained by complex formation between lithium salts, such as CF3SO3Li, and Lewis acids, such as AlCl3 and NbF5. A room temperature ionic liquid containing the lithium cation was discovered in the CF3SO3Li-AlCl 3 system. This ionic liquid exhibits room temperature Conductivity higher than 10--3 S/cm. New polymer electrolytes containing rigid polymers were synthesized and characterized. These novel polymer electrolytes exhibit high conductivity and good mechanical properties. The best conductivity, 10--4 S/cm at room temperature, was observed for the poly(1,3-dioxolan-2-one-4,5-(diyl oxalate)-LiCF3SO3 system. Many properties of these new polymer electrolytes are significantly different from traditional polymer electrolytes. Addition of salt usually softens these new polymer systems instead of stiffening the polymers as in conventional polymer electrolytes. Unlike traditional polymer electrolytes, where conductivity predominates in amorphous phases, these new polymer electrolytes exhibit conductivity in both crystalline and amorphous phases. These properties indicate that the ion conduction mechanism in these rigid polymer electrolytes is different from that in the conventional polymer electrolytes. Solid electrolytes with high ionic conductivity were discovered in the LiI-MI systems, where M is K, Rb or Cs. The highest conductivity was observed with the LiI-RbI system. For example, Li2Rb3I5 exhibits a conductivity of 1.2 x 10--2 S/cm at 65°C. The conductive phases change to resistive phases at lower temperatures. Solid anhydrous proton conductors, with room temperature conductivity higher than 10--3 S/cm, were discovered in the mixtures of hydrogen sulfate and sulfate salts. These materials include Li2SO 4-LiHSO4, BeSO4-Be(HSO4)2 and Al2(SO4)3-Al(HSO4)3.

Wei, Xiangyun

1999-11-01

427

The Spacecraft Materials Selector: An Artificial Intelligence System for Preliminary Design Trade Studies, Materials Assessments, and Estimates of Environments Present  

NASA Technical Reports Server (NTRS)

Institutions need ways to retain valuable information even as experienced individuals leave an organization. Modern electronic systems have enough capacity to retain large quantities of information that can mitigate the loss of experience. Performance information for long-term space applications is relatively scarce and specific information (typically held by a few individuals within a single project) is often rather narrowly distributed. Spacecraft operate under severe conditions and the consequences of hardware and/or system failures, in terms of cost, loss of information, and time required to replace the loss, are extreme. These risk factors place a premium on appropriate choice of materials and components for space applications. An expert system is a very cost-effective method for sharing valuable and scarce information about spacecraft performance. Boeing has an artificial intelligence software package, called the Boeing Expert System Tool (BEST), to construct and operate knowledge bases to selectively recall and distribute information about specific subjects. A specific knowledge base to evaluate the on-orbit performance of selected materials on spacecraft has been developed under contract to the NASA SEE program. The performance capabilities of the Spacecraft Materials Selector (SMS) knowledge base are described. The knowledge base is a backward-chaining, rule-based system. The user answers a sequence of questions, and the expert system provides estimates of optical and mechanical performance of selected materials under specific environmental conditions. The initial operating capability of the system will include data for Kapton, silverized Teflon, selected paints, silicone-based materials, and certain metals. For situations where a mission profile (launch date, orbital parameters, mission duration, spacecraft orientation) is not precisely defined, the knowledge base still attempts to provide qualitative observations about materials performance and likely exposures. Prior to the NASA contract, a knowledge base, the Spacecraft Environments Assistant (SEA,) was initially developed by Boeing to estimate the environmental factors important for a specific spacecraft mission profile. The NASA SEE program has funded specific enhancements to the capability of this knowledge base. The SEA qualitatively identifies over 25 environmental factors that may influence the performance of a spacecraft during its operational lifetime. For cases where sufficiently detailed answers are provided to questions asked by the knowledge base, atomic oxygen fluence levels, proton and/or electron fluence and dose levels, and solar exposure hours are calculated. The SMS knowledge base incorporates the previously developed SEA knowledge base. A case history for previous flight experiment will be shown as an example, and capabilities and limitations of the system will be discussed.

Pippin, H. G.; Woll, S. L. B.

2000-01-01

428

A standard reference for chamber testing of material VOC emissions: Design principle and performance  

NASA Astrophysics Data System (ADS)

Environmental chambers are widely used to test formaldehyde and other volatile organic compound (VOC) emissions from indoor materials and furniture. However, there is a lack of a proven method to assess the precision of the test results of the chamber system. In this paper, we describe a new standard reference, LIFE (liquid-inner tube diffusion-film-emission), to address this problem. This reference has the following salient features: (1) Constant emission rate, with less than 3.0% change with an ambient airflow speed (>0.014 m/s) at furniture emission range (0.1-1.0 mg/m 3 in a 30 m 3 chamber with air change rate of 1/h) under standard chamber test conditions as specified by ISO 16000-9 (23 °C, 50% RH); (2) Long duration of emissions, on the order of 1000 h; (3) Easy to store, apply and maintain. The design principle and criteria of the LIFE reference are presented. An analytical model and dimensionless analysis were applied to optimize the factors influencing the emission rate, and experiments were conducted to validate the analytical results. In addition, the equivalent emission parameters of the reference, i.e., the initial emittable concentration, the diffusion coefficient and the partition coefficient, were determined through a three-parameter optimizing regression. This can then be used to check the reliability of a chamber method for testing these three parameters. The developed standard reference should prove useful for calibrating chamber systems for indoor material/furniture VOC emissions tests.

Wei, Wenjuan; Zhang, Yinping; Xiong, Jianyin; Li, Mu

2012-02-01

429

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

NASA Technical Reports Server (NTRS)

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

Luz, P. L.; Rice, T.

1998-01-01

430

Design, synthesis, and characterization of materials for controlled line deposition, environmental remediation, and doping of porous manganese oxide material  

NASA Astrophysics Data System (ADS)

This thesis covers three topics: (1) coatings formed from sol-gel phases, (2) environmental remediation, and (3) doping of a porous manganese oxide. Synthesis, characterization, and application were investigated for each topic. Line-formations were formed spontaneously by self-assembly from vanadium sol-gels and other metal containing solutions on glass substrates. The solutions were prepared by the dissolution of metal oxide or salt in water. A more straightforward method is proposed than used in previous work. Analyses using optical microscopy, atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and infrared spectroscopy showed discreet lines whose deposition could be controlled by varying the concentration. A mechanism was developed from the observed results. Microwave heating, the addition of graphite rods, and oxidants, can enhance HCB remediation from soil. To achieve remediation, a TeflonRTM vessel open to the atmosphere along with an oxidant, potassium persulfate (PerS) or potassium hydroxide, along with uncoated or aluminum oxide coated, graphite rods were heated in a research grade microwave oven. Microwave heating was used to decrease the heating time, and graphite rods were used to increase the absorption of the microwave energy by providing thermal centers. The results showed that the percent HCB removed was increased by adding graphite rods and oxidants. Tungsten, silver, and sulfur were investigated as doping agents for K--OMS-2. The synthesis of these materials was carried out with a reflux method. The doping of K--OMS-2 led to changes in the properties of a tungsten doped K--OMS-2 had an increased resistivity, the silver doped material showed improved epoxidation of trans-stilbene, and the addition of sulfur produced a paper-like material. Rietveld refinement of the tungsten doped K--OMS-2 showed that the tungsten was doped into the framework.

Calvert, Craig A.

431

The effect of material properties and tooling design on deformation and fracture during equal channel angular extrusion  

SciTech Connect

The effects of material constitutive behavior, tooling design, and friction conditions on metal flow, stress fields, and the tendency for tensile fracture during equal channel angular extrusion (ECAE) were established using a finite element modeling (FEM) technique. Three different material behaviors, typical of those encountered during cold and hot working, were investigated; these comprised (1) string hardening, (2) rigid, perfectly plastic, and (3) flow softening types of behavior. The tooling geometries consisted of a so-called simple design with no moving channel members and a complex design with a sliding bottom floor. The FEM results indicated that the most uniform flow was obtained during ECAE of a strain-hardening material having a low strain-rate sensitivity in tolling with a sharp inner corner (front leg) radius. The ECAE of materials with other constitutive behaviors or in tooling with a radiused front leg showed some degree of flow nonuniformity, even away from the head and tail of the extrusion. Tooling design and material properties were also predicted to have an important influence on the tensile stresses and hence tensile damage developed during ECAE. The FEM results were validated using visioplasticity and fracture observations for AISI 4340 steel and a near-gamma titanium aluminide alloy.

Semiatin, S.L.; Delo, D.P.; Shell, E.B.

2000-05-11

432

Design, Implementation, and Evaulation of GIS-Based Learning Materials in an Introductory Geoscience  

NSDL National Science Digital Library

Little is known about how well GIS-based learning lives up to its potential for improving students\\' skills in problem solving, analysis, and spatial visualization. This article describes a study in which researchers determined ways to quantify student learning that occurred with a GIS-based module on plate tectonics and geologic hazards, and to improve the materials design with the use of classroom observations and field testing. The study found that student difficulties in working with GIS-based activities can be overcome by making some features of the GIS transparent to the user, that a lack of basic geography skills can interfere in the progression of a GIS-based activity, and that some conceptual difficulties can be overcome by providing guiding questions that help students interrogate visual data. In addition, it was noted that some misconceptions in interpretation of two-dimensional maps and three-dimensional block diagrams can persist even after direct instruction. In general, a positive correlation was noted between spatial thinking and GIS-based learning.

Hall-Wallace, Michelle

433

Polymer microfabrication by scanning based microstereolithography: Optical design and material functionality  

NASA Astrophysics Data System (ADS)

Several research groups have attempted to optimize photopolymerization parameters to increase the throughput of scanning based microstereolithography (MSL) systems through modified beam scanning techniques. Efforts in reducing the curing line width have been implemented through high numerical aperture (NA) optical setups. However, the intensity contour symmetry and the depth of field of focus have led to grossly non-vertical and non-uniform curing profiles. This work tries to review the photopolymerization process in a scanning based MSL system from the aspect of material functionality and optical design. The focus has been to exploit the rich potential of photoreactor scanning system in achieving desired fabrication modalities (minimum curing width, uniform depth profile, and vertical curing profile) even with a reduced NA optical setup and a single movable stage. The present study tries to manipulate to its advantage the effect of optimized lower [c] (photoinitiator (PI) concentration) in reducing the minimum curing width to ˜10-20 ?m even with a higher spot size (˜21.36 ?m) through a judiciously chosen "monomer-PI" system. Optimization on grounds of increasing Emax (maximum laser exposure energy at surface) by optimizing the scan rate provides enough time for the monomer or resin to get cured across the entire resist thickness (surface to substrate ˜10-100 ?m), leading to uniform depth profiles along the entire scan lengths.

Goswami, Ankur; Phani, Arindam; Umarji, A. M.; Madras, Giridhar

2012-09-01

434

Tool design in friction stir processing: dynamic forces and material flow  

SciTech Connect

Friction stir processing involves severe plastic flow within the material; the nature of this flow determines the final morphology of the weld, the resulting microstructures, and the presence or absence of defects such as internal cavities or "wormholes." The forces causing this plastic flow are a function of process parameters, including spindle speed, travel speed, and tool design and angle. Some of these forces are directly applied or a result of the mechanical constraints and compliance of the apparatus, while others are resolved forces resulting from an interaction of these applied forces and tool forces governed by processing parameters, and can be diminished or even reversed in sign with appropriate choices of process parameters. The present investigation is concerned mostly with the friction stir processing of 6061-T6 aluminum plates in a low-cost apparatus built from a commercial milling machine. A rotating dynamometer allows in-process measurement of actual spindle speed, torque, and forces in the x-, y-, and z-directions, as well as force control on these axes. Two main types of tool, both unthreaded, were used. The first had a pin about 4 mm in diameter and 4 mm in length, with a shoulder about 10 mm in diameter, and produced wormhole defects; the second, with a tapered pin about 5 mm long, a base diameter of about 6 mm, a tip diameter of about 4 mm, and a shoulder diameter (flat or dished) of about 19 mm, produced sound welds over a wide range of parameters.

D. E. Clark; K. S. Miller; C. R. Tolle

2006-08-01

435

Guiding principles for printed education materials: design preferences of people with aphasia.  

PubMed

The objectives of this study were to obtain the preferences of people with aphasia for the design of stroke and aphasia printed education materials (PEMs) and to compare these preferences with recommendations in the literature for developing written information for other populations. A face-to-face quantitative questionnaire was completed with 40 adults with aphasia post-stroke. The questionnaire explored preferences for: (1) the representation of numbers, (2) font size and type, (3) line spacing, (4) document length, and (5) graphic type. Most preferences (62.4%, n = 146) were for numbers expressed as figures rather than words. The largest proportion of participants selected 14 point (28.2%, n = 11) and Verdana ref (33.3%, n = 13) as the easiest font size and type to read, and a preference for 1.5 line spacing (41.0%, n = 16) was identified. Preference for document length was not related to the participant's reading ability or aphasia severity. Most participants (95.0%, n = 38) considered graphics to be helpful, with photographs more frequently reported as a helpful graphic type. The identified preferences support many of the formatting recommendations found within the literature. This research provides guiding principles for developing PEMs in preferred formats for people with aphasia. PMID:22136650

Rose, Tanya A; Worrall, Linda E; Hickson, Louise M; Hoffmann, Tammy C

2012-02-01

436

New developments in the Inorganic Crystal Structure Database (ICSD): accessibility in support of materials research and design.  

PubMed

The materials community in both science and industry use crystallographic data models on a daily basis to visualize, explain and predict the behavior of chemicals and materials. Access to reliable information on the structure of crystalline materials helps researchers concentrate experimental work in directions that optimize the discovery process. The Inorganic Crystal Structure Database (ICSD) is a comprehensive collection of more than 60,000 crystal structure entries for inorganic materials and is produced cooperatively by Fachinformationszentrum Karlsruhe (FIZ), Germany, and the US National Institute of Standards and Technology (NIST). The ICSD is disseminated in computerized formats with scientific software tools to exploit the content of the database. Features of a new Windows-based graphical user interface for the ICSD are outlined, together with directions for future development in support of materials research and design. PMID:12037357

Belsky, Alec; Hellenbrandt, Mariette; Karen, Vicky Lynn; Luksch, Peter

2002-06-01

437

Predicting Material Performance in the Space Environment from Laboratory Test Data, Static Design Environments, and Space Weather Models  

NASA Technical Reports Server (NTRS)

Qualifying materials for use in the space environment is typically accomplished with laboratory exposures to simulated UV/EUV, atomic oxygen, and charged particle radiation environments with in-situ or subsequent measurements of material properties of interest to the particular application. Choice of environment exposure levels are derived from static design environments intended to represent either mean or extreme conditions that are anticipated to be encountered during a mission. The real space environment however is quite variable. Predictions of the on orbit performance of a material qualified to laboratory environments can be done using information on 'space weather' variations in the real environment. This presentation will first review the variability of space environments of concern for material degradation and then demonstrate techniques for using test data to predict material performance in a variety of space environments from low Earth orbit to interplanetary space using historical measurements and space weather models.

Minow, Josep I.; Edwards, David L.

2008-01-01

438

Towards rational design of peptides for selective interaction with inorganic materials  

E-print Network

Utilizing molecular recognition and self-assembly, material-specific biomolecules have shown great promise for engineering and ordering materials at the nanoscale. These molecules, inspired from natural biomineralization ...

Krauland, Eric Mark

2007-01-01

439

EFFECTIVE MATERIALS PROPERTIES: DETERMINATION AND APPLICATION IN MECHANICAL DESIGN AND OPTIMIZATION  

E-print Network

the effective properties of the cobalt-tungsten carbide (Co-WC) two-phase material. The organization of the paper is as follows: A brief overview of the procedure for computer-based generation of the materials

Grujicic, Mica

440

TRANSPORTATION ADMINISTRATION MANAGEMENT DESIGN INFORMATION SYSTEMS MATERIALS MULTIMODAL INTEGRATION RESEARCH SAFETY RAILROADS ITS TOLL ROADS LEGISLATURE  

E-print Network

INTEGRATION RESEARCH SAFETY RAILROADS ITS TOLL ROADS LEGISLATURE BRIDGE STRUCTURES AND HYDRAULICS RIGHT MATERIALS RESEARCH SAFETY RAILRO