The equilibrium vapor pressure of antimony triiodide (SbI3) has been measured over a temperature range from 20 to 47 C using a classical Knudsen cell method. An analysis of the slope of that data as a function of temperature yields an enthalpy of sublimation (Hvapor) value of Hvapor = 128.48 kJ/mol for SbI3.
Topics: DTIC Archive, Taylor, Patrick J, US Army Research Laboratory Adelphi United States, doping,...
This project aims to develop a novel three-stage coupled multi-scale QM-MD-SPH approach for modeling and simulation of complex heterogeneous multicomponent reactive systems, considering both high explosive (HE) explosion effects. The novelty of our approach is that the unified particle-based approaches couples the dynamic events over nine orders of magnitude length scales (nm-m) and twelve orders of magnitude timescales (ps-s). This is achieved by using ab initio quantum mechanics (QM)...
Topics: DTIC Archive, Liu,Guirong, University of Cincinnati Cincinnati United States, crystal structure,...
We have designed and grown LaAlO3/SrTiO3 oxide hetero-interfaces and switchable 2DEG by using pulsed laser deposition atomic within-situ reflection high-energy electron diffraction (RHEED). We have also demonstrated that the inline electron holography can directly visualize the 2DEG at the both (001) and (111) LAO/STO interface. Taking an example of 2DEGs forming at LAO/STO interfaces with different crystal symmetry, we have shown that the selective orbital occupation and spatial quantum...
Topics: DTIC Archive, EOM, CHANG BEOM, UNIVERSITY OF WISCONSIN SYSTEM MADISON United States, metamaterials,...
Alumina (Al2O3, aluminum oxide) is an excellent candidate as an optical material for laser gain media due to its high thermal conductivity. However, a rare earth (RE) cation dopant is necessary for the material to lase. To combat the dopant issue, nanosized alumina particles were synthesized via co-precipitation to trap RE ions in the alumina lattice before calcination. The wet co-precipitation process allowed for high purity and homogeneous distribution of the RE ions within the particles. A...
Topics: DTIC Archive, Ku,Nicholas, US Army Research Laboratory Aberdeen Proving Ground United States,...
The objective of this project is to investigate, theoretically and experimentally, the flexoelectricity at nanometer scale, and explore the feasibility of using flexoelectric micro/nanostructures for novel sensing including seismic, acoustic and IR detections. FE induced effective piezoelectric properties in FE nanostructures could be a few order of magnitudes higher over their conventional bulk materials properties, which will lead to ultrasensitive electromechanical sensors using FE...
Topics: DTIC Archive, Jiang, Xiaoning, North Carolina State University Raleigh United States, dielectric...
The burgeoning field of high-entropy alloys (HEAs) is underpinned by two foundational concepts, and early research has been motivated by several hypotheses known as core effects. The field is now entering its teenage years, and sufficient data have been collected to evaluate these hypotheses and to take a fresh look at the foundational concepts. Although recent assessments have concluded that two of the four HEA hypotheses are not supported by available data, new studies are already coming...
Topics: DTIC Archive, Miracle,Daniel B, AFRL Materials and Manufacturing Directorate Wright Patterson Air...
NUCu-140 and 10 wt% Ni steel were developed as candidate materials for use in naval and structural applications. However, prior to this research project, a fundamental understanding of the phase transformation behavior under the high heating and cooling rates associated with welding thermal cycles was not available for these alloys. For NUCu-140, the potential use of multiple thermal cycles was investigated with HAZ simulations using a Gleeble thermo-mechanical simulator. For 10 wt% Ni steel,...
Topics: DTIC Archive, DuPont, John N, Lehigh University, Department of Materials Science and Engineering...
The primary aim of this research project was to apply a novel topological and electronic-based model recently developed by the principal investigator in collaboration with the US Air Force Research Laboratory for accurately predicting compositions of new amorphous alloys specifically based on aluminium with properties superior to commercial crystalline metals and existing amorphous alloys. This research investigated alloy families that contained a variety of elements including Al, Cu, Ni, Zr,...
Topics: DTIC Archive, Laws,Kevin, UNIVERSITY OF NEW SOUTH WALES KENSINGTON Australia, crystal structure,...
In this final report, they highlight their attempt to develop a method for generating networks of micro- and nano-capillaries within a ceramic composite during the sintering process at atmospheric pressure. They then present test results of the multifunctional composites for self-powered supply of fluids to the contact (load-bearing) surface via the capillary networks from a fluid reservoir. As a further extension, a self-regulation mechanism is added into the design to enable...
Topics: DTIC Archive, Xu, Jingming, BROWN UNIVERSITY IN PROVIDENCE IN STATE OF RI AND PROVIDENCE...
The goal of the research was to develop a new methodology for the fabrication and the design of new multifunctional composites and devices using 3D printing. The main accomplishments of this project can be summarized as follows: 1) Proposing and demonstrating the 4D printing concept and novel printed active composites (PACs); 2) developing multiple PAC continuum mechanics PAC models of various levels of accuracy and complexity; 3) developing the 4D printing concept to design PACs undergoing...
Topics: DTIC Archive, Maute,Kurt, University of Colorado Boulder Boulder United States, additive...
This project studies collisional phenomena such as thermalization and diffusion in strongly coupled plasmas. In strongly coupled plasmas, the Coulomb interaction energy per particle exceeds the thermal energy. This occurs in high-energy-density plasmas such as inertial confinement fusion experiments and in nature in the interiors of gas giant planets and the crusts of neutron stars. Classical plasma theory breaks down in strongly coupled systems because of the non-perturbative nature of...
Topics: DTIC Archive, Killian,Thomas C, Rice University Houston United States, complex systems, laser...
Polyhedral Oligomeric Silsesquioxanes (POSS) are inorganic/organic cages that are used as high-tech additives to enhance the thermal, mechanical and surface properties of many polymeric systems. A useful analogy is that a POSS is nano-sized particle of silica solubilzed with organic modifiers (RSiO1.5)n; the organic periphery determines how well the POSS can interact with any host polymer, while the siliceous core adds thermoxidative stability. Beginning in 1993 and continuing today, there has...
Topics: DTIC Archive, Haddad, Timothy S, AIR FORCE RESEARCH LAB EDWARDS AFB CA EDWARDS AFB United States,...
A high-pressure phase of croconic acid is being investigated as a novel energetic material. When pressed at high pressures (5.5 GPa), as-received croconic acid transforms into a beta-phase that is recoverable to ambient conditions. This phase has a higher density and heat of combustion than the as-received material. Rectangular crystals, which are darker than the original powder, can be observed in the recovered material and are thought to indicate formation of the beta-phase. When croconic...
Topics: DTIC Archive, Isert ,Sarah, US Army Research Laboratory Aberdeen Proving Ground United States,...
Research with the goal of understanding the chemistry of an Inorganic Aqueous Solution (IAS)used as a working fluid in copper and aluminum phase change heat transfer devices, finding the advantages and limits of IAS in various heat transfer applications, and providing a general guideline of how to correctly use IAS for performance enhancement and surface passivation purposes was performed.
Topics: DTIC Archive, Yao,Qi, University of California, Los Angeles Los Angeles United States, chemistry,...
A fundamental research program of combined shock loading and intense terahertz-frequency (THz) irradiation of energetic materials was supported. The program has high risk since the effects of high THz fields on shocked energetic materials or shocked materials of any kind were entirely unexplored. The program has potential for high payoff in the form of fundamental discovery that could be exploited for greatly accelerated release of chemical energy stored in energetic materials. Support for the...
Topics: DTIC Archive, Nelson,Keith A, MASSACHUSETTS INST OF TECH CAMBRIDGE CAMBRIDGE United States,...
Damage in polymer and composite materials is often rapid and catastrophic. Preventing damage requires a new class of material that can autonomically respond to imminent damage by rapidly changing its physical properties. Herein we report several mechanisms by which autonomic material self-protection may be realized. The incorporation of encapsulated super cooled fluids into a polymer matrix allows for rapid changes in mechanical properties. Frontal polymerization within a microvascular network...
Topics: DTIC Archive, Moore, Jeff, University of Illinois at Urbana-Champaign Champaign United States,...
Topics: DTIC Archive, Miracle,D B, UES INC DAYTON OH DAYTON United States, alloys, microstructure,...
Temperature histories of structural steel deep-penetration welds are presented, which are calculated using numerical-analytical basis functions and solidification-boundary constraints. These weld temperature histories can be adopted as input data to various types of computational procedures, which include numerical models for prediction of solid-state phase transformations and mechanical response. In addition, these temperature histories can be used parametrically for inverse thermal analysis...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC CENTER FOR COMPUTATIONAL MATERIALS SCIENCE,...
Thin layers of single-crystal, epitaxial semiconductor tin (alpha-Sn) were grown by molecular beam epitaxy (MBE) on cadmium telluride (CdTe) substrates. X-ray diffraction and Raman scattering measurements confirm that the thin layers of alpha-Sn are slightly strained, which supports theoretical prediction that alpha-Sn is a 3-D topological insulator (TI). Future studies will aim at the growth of alpha-Sn with improved transport characteristics using high-quality CdTe buffer layers, studies of...
Topics: DTIC Archive, Folkes,P, Sensors Electron and Devices Directorate, US Army Research Laboratory...
Real-life quantum computers are inevitably affected by intrinsic noise resulting in dissipative nonunitary dynamics realized by these devices. We consider an open-system quantum annealing algorithm optimized for such a realistic analog quantum device which takes advantage of noise-induced thermalization and relies on incoherent quantum tunneling at finite temperature. We theoretically analyze the performance of this algorithm considering a p-spin model that allows for a mean-field...
Topics: DTIC Archive, Kechedzhi, Kostyantyn, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA...
Recent years have seen exciting new developments in mathematics and computer science, which have opened up new domains of application for computational mathematics. These come with new challenges, for which new approaches and tools must be and are being developed. Machine learning and compressive sensing are two typical examples; they draw not only from traditional linear algebra based numerical analysis or approximation theory, but also from information theory, graph theory, the geometry of...
Topics: DTIC Archive, Singer,Amit, Princeton University Princeton United States, INFORMATION THEORY,...
We have studied the properties of layered transition metal compounds in search of unconventional superconductors. The aim is to identify ground states competing with superconductivity, and to use tuning parameters such as doping or pressure, to reveal the effects of this competition. The key results from the project are: -the discovery of remarkable transport properties in the doped layered dichalcogenide TiSe2, where Pt doping or Se deficiency result in a 10 order of magnitude change in the...
Topics: DTIC Archive, Morosan,Emilia, Rice University Houston United States, superconductivity, magnetism,...
During 2012-2013, some analytical models have been developed and the results were inputted to the Synopsys Sentaurus TCAD. Thedevice structure and dimension were optimized and the device performance was tested for conductive substrate and semi-insulatingsubstrate. The wafer specification and mask layout were prepared by the combination of Synopsys Sentaurus TCAD and analyticalmodeling. In 2014, high quality oxide development has been obtained by the combination of thermal oxidation and...
Topics: DTIC Archive, Chattopadhyay,Somnath, California State University - Northridge Northridge United...
The project period features multiple advances at different frontiers of ultracold atom science. Our approach has been a joint experimental and theoretical effort. Experimentally, new technologies for optical lattices were implemented, including a two-layer quantum microscope, a flexible hexagonal lattice where the geometry of the lattice can be changed by polarization control, and a new fluorescence detection scheme for potassium using blue light.
Topics: DTIC Archive, Ketterle,Wolfgang, Massachusetts Institute of Technology Cambridge United States,...
This project develops a theoretical model for gases of bosonic atoms at ultracold, but finite temperatures. Under these circumstances, the gas can undergo a phase transition to a purely quantum mechanical state, a Bose-Einstein condensate (BEC), where the atoms cease to behave like distinguishable entities, and instead form a single macroscopic matter wave. At exactly zero temperature, all of the atoms occupy the BEC; at finite temperatures, a significant fraction of the atoms leave the BEC and...
Topics: DTIC Archive, NAVAL ACADEMY ANNAPOLIS MD ANNAPOLIS United States, bose einstein condensates,...
The focus of this proposal was theoretical research on various nonequilibrium phenomena in isolated quantum systems and applications to experimental setups largely to cold atoms. All goals stated in the proposal were addressed. In addition two conceptually new ideas have emerged (Floquet systems and application of phase space methods to strongly interacting systems). These ideas were partly addressed in recent publications and partly they underlined the renewal proposal of this grant. Overall...
Topics: DTIC Archive, Polkovnikov,Anatoli, Trustees of Boston University Boston United States, dynamics,...
Concepts from Finsler differential geometry are applied toward a theory of deformable continua with microstructure. The general model accounts for finite strains, nonlinear elasticity, and various kinds of structural defects in a solid body. The general kinematic structure of the theory includes macroscopic and microscopic displacement fields (i.e., a multiscale theory) whereby the latter are represented mathematically by the director vector of pseudo-Finsler space, not necessarily of unit...
Topics: DTIC Archive, Clayton, John D, US Army Research Laboratory Aberdeen Proving Ground United States,...
Electron microscopy, X-ray energy dispersive spectroscopy, and tomographic reconstructions were used to characterize a high entropy alloy predominantly composed of refractory elements. The intragranular microstructure was found to consist of a periodic two phase mixture, where a disordered bcc phase is aligned orthogonally in an ordered B2 phase. The phases were found to exhibit continuous lattice registry and an orientation relationship given by 100 bcc//100 B2, {001}bcc//{001}B2. X-ray energy...
Topics: DTIC Archive, Senkov,O N, electron microscopy, electron tomography, xray computed tomography, phase...
Majorana fermions (MFs) are quantum particles that are their own anti-particles, and satisfy non-Abelian exchange statistics. The latter is the key for their potential use in fault-tolerant topological quantum computation. In this project, we proposed to investigate the possibility of realizing MFs in much more physically robust s-wave superfluids by utilizing two additional components: spin-orbit coupling and Zeeman fields. In the last year grant period, we have made the following important...
Topics: DTIC Archive, Zhang,Chuanwei, University of Texas at Dallas Richardson United States, Fermions,...
Microstructure, phase composition and mechanical properties of a refractory high entropy super alloy, AlMo(sub 0.5)NbTa(sub 0.5)TiZr, are reported in this work. The alloy consists of a nano-scale mixture of two phases produced by the decomposition from a high temperature body-centered cubic (BCC) phase. The first phase is present in the form of cuboidal-shaped nano-precipitates aligned in rows along 100-type directions, has a disordered BCC crystal structure with the lattice parameter a(sub 1)...
Topics: DTIC Archive, Senkov,Oleg N, AFRL Materials and Manufacturing Directorate Wright Patterson Air...
Complex networks have been shown to exhibit universal properties, with one of the most consistent patterns being the scale-free degree distribution, but are there regularities obeyed by the r-hop neighborhood in real networks? We answer this question by identifying another power-law pattern that describes the relationship between the fractions of node pairs C(r) within r hops and the hop count r. This scale-free distribution is pervasive and describes a large variety of networks, ranging from...
Topics: DTIC Archive, Papalexakis,Evangelos, CARNEGIE-MELLON UNIV PITTSBURGH PA PITTSBURGH United States,...
Topics: DTIC Archive, FENG,ZHILI, US ARMY TARDEC WARREN United States, Hydrogen embrittlement, Steel,...
Characterizing the fast evolution of microstructural defects is key to understanding crackling phenomena during the deformation of solid materials. For example, it has been proposed using atomistic simulations of crack propagation in elastic materials that the formation of a nonlinear hyperelastic or plastic zone around moving crack tips controls crack velocity. To date, progress in understanding the physics of this critical zone has been limited due to the lack of data describing the complex...
Topics: DTIC Archive, Ghaffari,H O, TEXAS UNIV AT ARLINGTON ARLINGTON United States, phase transformations,...
Vanadium dioxide (VO2) is known to have a semiconductor-to-metal phase transition at 68C. Therefore, it can be used as a tunable component of an active metamaterial. The lamellar metamaterial studied in this work is composed of subwavelength VO2 and Au layers and is designed to undergo a temperature controlled transition from the optical hyperbolic phase to the metallic phase. VO2 films and VO2/Au lamellar metamaterial stacks have been fabricated and studied in electrical conductivity and...
Topics: DTIC Archive, Liberman,Vladimir, MASSACHUSETTS INST OF TECH LEXINGTON LEXINGTON United States, THIN...
The stochastic gradient decent algorithm is the now the algorithm of choice for very large machine learning problems. We introduced the idea of stochastic modified equation to the analysis of such algorithms. This approach allows us to obtain very precise information about the behavior of the algorithm. At the same time, we were also able to formulate various acceleration techniques in precise math terms (e.g. formulate them as stochastic control problems) and obtain precise information about...
Topics: DTIC Archive, PRINCETON UNIV NJ, *STOCHASTIC CONTROL, ALGORITHMS, BEHAVIOR, DIFFERENTIAL EQUATIONS,...
The AFOSR support has enabled us to discover new superconductors with higher Tc, for science and potential new applications, or with low Tc but with novel structure-types for new discoveries; to realize new superconducting mechanism for higher Tc; to unravel new physics important to high Tc and Jc; to discover new physics and phenomena in non-superconducting but related compounds for HTS development and devices; to develop single-crystal growth capability and new techniques; to evaluate...
Topics: DTIC Archive, Chu,Ching-Wu, University of Houston Houston United States, superconductors, HIGH...
The Institute for Science and Engineering Simulation (ISES), at the University of North Texas, has developed and applied novel materials characterization, modeling, and simulation tools to aid in the future inspection, repair and design of improved materials and processes for aerospace applications. Specifically, the program has aided in establishing the fundamental understanding required to support safety engineers in their ability to upgrade and maintain the Air Forces aging fleet by...
Topics: DTIC Archive, Banerjee,Rajarshi, University of North Texas Denton United States, alloys,...
Inverse thermal analyses of structural steel deep-penetration welds are presented. These analyses employ a methodology that is in terms of numerical-analytical basis functions and multiple constraint conditions for inverse thermal analysis of steady state energy deposition in plate structures. These analyses provide parametric representations of weld temperature histories that can be adopted as input data to various types of computational procedures, such as those for prediction of solid-state...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC MATERIALS SCIENCE AND TECHNOLOGY DIV, *LASERS,...
Inverse thermal analyses of structural steel deep-penetration welds are presented. These analyses employ a methodology that is in terms of numerical-analytical basis functions and multiple constraint conditions for inverse thermal analysis of steady state energy deposition in plate structures. These analyses provide parametric representations of weld temperature histories that can be adopted as input data to various types of computational procedures, such as those for prediction of solid-state...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC MATERIALS SCIENCE AND TECHNOLOGY DIV, *LASERS,...
We discovered the buckling of elastically heterogeneous nano-containers into regular and irregular polyhedral geometries observed in organelles of multicomponent proteins and in halophilic organisms. We determined the physical properties of ionic membranes. By co-assembling cationic and anionic amphiphiles programmed to form ionic crystalline vesicles we demonstrated the buckling model and produced biomimetic organelles. We extended the model to describe the blebbing of nuclear lamina in cells...
Topics: DTIC Archive, Olvera de la Cruz,Monica, Northwestern University Evanston United States, chemistry,...
Luminescent rare-earth doped metal oxides are evaluated as potential temperature sensors that are seeded into explosive fireballs and collected post-detonation for analysis. The sensors consist of amorphous precursors which, once subjected to thermal exposure, undergo irreversible phase transitions such as decomposition, nucleation, and grain growth. The extent and degree of these phase transitions depends on temperature and heating duration. The phase transitions are monitored via spectral...
Topics: DTIC Archive, Hergen,Eilers, Washington State University Pullman, heat treatment, explosions, METAL...
A common problem in modern graph analysis is the detection of communities, an example of which is the detection of a single anomalously dense subgraph. Recent results have demonstrated a fundamental limit for this problem when using spectral analysis of modularity. In this paper, we demonstrate the implication of these results on community detection when a cue vertex is provided, indicating one of the vertices in the community of interest. Several recent algorithms for local community detection...
Topics: DTIC Archive, Miller,Benjamin A, MIT Lincoln Laboratory Lexington United States, graphs,...
Using theoretical and computational chemistry methods, we have studied the oxygen reduction and proton transfer in molten carbonate salts related to solid oxide fuel cells, and adsorption of nerve agents of sarin on surfaces of CaO, graphene and graphane. The mechanism of oxygen reduction through CO52- and CO42- is confirmed for the first time by DFT. It was found the proton has very good mobility in molten carbonate salts with activation energy of 8.0 kcal/mol, which agrees with the value...
Topics: DTIC Archive, Whitten,Jerry L, Benedict College Columbia United States, Oxidation reduction...
This project primarily investigated computationally the infusion of liquid elements from the Hf family (i.e., Hf, Ti and Zr) into a capillary to understand the effects of surface tension and viscosity during processing of melts with a packed bed of B4C to form boridecarbide precipitates. Although the ultimate goal of the research endeavor is to enhance significantly the oxidation resistance of ultrahigh temperature ceramic composites (UHTCC), the processing of these reactive metals and...
Topics: DTIC Archive, TEXAS UNIV AT EL PASO, *BORIDES, *CARBIDES, *COMPUTATIONAL FLUID DYNAMICS, *OXIDATION...
Because phase change materials (PCMs) can absorb or release heat when they undergo phase changes (solid to liquid, liquid to solid, or solid to gas), they are considered especially promising candidates for use in heating and cooling applications for building envelopes. This work investigated the stability of four commercially available PCMs, and developed an accelerated testing protocol to simulate the long-term performance of PCMs in an operational scenario. The selected PCM s were subjected...
Topics: DTIC Archive, ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING...
Objectives of this project included the preparation of novel chemical explosive compounds capable of producing biocidal products of explosion (particularly hydrogen fluoride) as well as one or more explosive formulations suitable for determination of their feasibility as effective agent defeat weapon components. Such new formulations could provide significantly better airborne-agent neutralization/defeat capabilities than existing high-explosive, thermobaric, and high-temperature incendiary...
Topics: DTIC Archive, NAVAL AIR WARFARE CENTER WEAPONS DIV CHINA LAKE CA, *BIOCIDES, *BIOLOGICAL AGENTS,...
Work under this grant focused on methods for extracting hidden information from network data, including data from social networks, networks of communications and interactions, heath or disease networks, and brain networks. During the last 12 months of this project, the funding level was cut substantially. Nevertheless, over this period, our team worked on several substantial projects, including the development of several powerful new algorithms for analyzing networks and their application to...
Topics: DTIC Archive, SANTA FE INST NM, *SYSTEMS ANALYSIS, ALGORITHMS, ANOMALIES, BAYES THEOREM, BEHAVIOR,...
Case study inverse thermal analyses of Ti-6Al-4V pulsed-mode laser welds are presented. These analyses employ a methodology that is in terms of numerical-analytical basis functions for inverse thermal analysis of steady state energy deposition in plate structures. The results of the case studies provide parametric representations of weld temperature histories that can be adopted as input data to various types of computational procedures, such as those for prediction of solid-state phase...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC, *LASER WELDING, *THERMAL ANALYSIS, *TITANIUM, CASE...
In this work, we discuss the design and fabrication of a nickel-titanium (Ni50Ti50) shape memory alloy (SMA) cantilever array that was thermally actuated by harnessing the residual stress difference during the martensite-to-austenite phase transformation during heating. The cantilever devices were fabricated on a silicon (Si) wafer using standard microfabrication techniques and released using a xenon difluoride (XeF2) dry-etch technique and may therefore be applicable to microelectromechanical...
Topics: DTIC Archive, ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE, *SHAPE MEMORY...
This report details the development of a co-sputtering process to yield a shape memory alloy (SMA) film with a controllable composition of nickel-titanium (Ni50Ti50) and transformation temperature around 60 C. Shape memory effects were characterized using differential scanning calorimetry (DSC), for which we demonstrated martensite-austenite phase change at 57 C for 1 3 m films annealed at 600 C for 1 h. We used wafer stress versus temperature measurements as additional confirmation for the...
Topics: DTIC Archive, ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE, *PHASE...
