Structure of the near-surface layer of NiTi on the meso- and microscale levels after ion-beam surface treatment

Using the EBSD, SEM and TEM methods, the structure of surface layer of polycrystalline NiTi alloy samples was examined after the modification of material surface by the pulsed action of mean-energy silicon ion beam. It was found that the ion beam treatment would cause grain fragmentation of the near-surface layer to a depth 5-50 [mu]m; a higher extent of fragmentation was observed in grains whose close-packed planes were oriented approximately in the same direction as the ion beam was. The effect of high-intensity ion beam treatment on the anisotropic behavior of polycrystalline NiTi alloy and the mechanisms involved were also examined

Synchronic variation in the expression of French negation - a Distributed Morphology approach

This article discusses ne-variation in French sentential negation based on the phonologically transcribed corpus T-zéro (cf. Meisner, in preparation) which allows a new interpretation of the facts. In the last decades, sociolinguistic and stylistic approaches to linguistic variation in French (cf. Armstrong, 2001) have shown that extra-linguistic factors, such as the speaker's age, sex, social background or geographic origin as well as the communication situation may have considerable influence on variable ne-omission. However, in contrast to most sociolinguistic studies dedicated to this phenomenon (cf. Ashby, 1976, 1981, 2001; Armstrong and Smith, 2002; Coveney, 2002) we will focus on the linguistic factors influencing ne-variation, since their importance is empirically evident but not yet fully exploited on a theoretical level. One leading assumption with respect to ne-variation in literature is that the particle ne is most frequently retained in combination with a proper name or a full DP and is commonly omitted when combined with clitic subjects. However, there are many exceptions to this rule which, as we argue, can be better explained by considering the phonological form of the involved subject. Ne-realisation is treated here as an inner-grammatical phenomenon that is triggered by context sensitivity with regard to the element to its left, i.e. usually the grammatical subject, and not as a consequence of ‘code-switching’ between two grammars nor as a sociolinguistic variable characterising certain groups of speakers in the Labovian sense (cf. Labov, 1972), since we seek to describe general variational tendencies, present in nearly all speakers of contemporary European French. Our analysis, which is implemented in a Distributed Morphology framework (Halle & Marantz, 1994), is compatible, however, with stylistic approaches to ne-variation, such as audience design (cf. Bell, 1984, 2001)

Non-dissipative Thermal Transport and Magnetothermal Effect for the Spin-1/2 Heisenberg Chain

Anomalous magnetothermal effects are discussed in the spin-1/2 Heisenberg chain. The energy current is related to one of the non-trivial conserved quantities underlying integrability and therefore both the diagonal and off diagonal dynamical correlations of spin and energy current diverge. The energy-energy and spin-energy current correlations at finite temperatures are exactly calculated by a lattice path integral formulation. The low-temperature behavior of the thermomagnetic (magnetic Seebeck) coefficient is also discussed. Due to effects of strong correlations, we observe the magnetic Seebeck coefficient changes sign at certain interaction strengths and magnetic fields.Comment: 4 pages, references added, typos corrected, Conference proceedings of SPQS 2004, Sendai, Japa

ARTIFICIAL INTELLIGENCE AND HUMAN INTERACTION: HOW TO KEEP THE HUMAN IN THE LOOP

Army leaders are looking to procure and implement artificial intelligence (AI) technologies to solve a variety of problems and enhance existing capabilities across multiple portfolios. While there are benefits to implementing new technologies, including AI, there is often a major pitfall: the human factor as a user is consistently underrepresented. This disparity between how AI-enabled systems are being acquired and how they should be acquired is often related to a gap in the development of systems not aligning with Human Systems Integration (HSI) best practices. The design of systems that facilitate human-agent learning requires further guidance. We use data from the System for Award Management (SAM) along with discussions from subject-matter experts both in government and industry to capture how AI-enabled systems are currently being procured by the Army. The combined results of the team's methodology revealed that there are varying understandings across the Army of what an AI requirement is, and there are no obvious processes or specific AI acquisition guidelines that are universally followed when developing an AI requirement. It was also apparent that HSI was not always included in requirements as required by Army regulations. This disparity appeared to have three major root causes: immaturity of DOD Army guidance, shortcomings in AI-related training for acquisition personnel, and a negligence surrounding the incorporation of HSI elements into Army requirements.CRUSERCivilian, Department of the ArmyCivilian, Department of the ArmyCivilian, Department of the ArmyCivilian, Department of the ArmyCivilian, Department of the ArmyApproved for public release. Distribution is unlimited

Optical Properties of MFe_4P_12 filled skutterudites

Infrared reflectance spectroscopy measurements were made on four members of the MFe_4P_12 family of filled skutterudites, with M=La, Th, Ce and U. In progressing from M=La to U the system undergoes a metal-insulator transition. It is shown that, although the filling atom induces such dramatic changes in the transport properties of the system, it has only a small effect on lattice dynamics. We discuss this property of the compounds in the context of their possible thermoelectric applications.Comment: Manuscript in ReVTeX format, 7 figures in PostScirpt forma

Thermomagnetic Power and Figure of Merit for Spin-1/2 Heisenberg Chain

Transport properties in the presence of magnetic fields are numerically studied for the spin-1/2 Heisenberg XXZ chain. The breakdown of the spin-reversal symmetry due to the magnetic field induces the magnetothermal effect. In analogy with the thermoelectric effect in electron systems, the thermomagnetic power (magnetic Seebeck coefficient) is provided, and is numerically evaluated by the exact diagonalization for wide ranges of temperatures and various magnetic fields. For the antiferromagnetic regime, we find the magnetic Seebeck coefficient changes sign at certain temperatures, which is interpreted as an effect of strong correlations. We also compute the thermomagnetic figure of merit determining the efficiency of the thermomagnetic devices for cooling or power generation.Comment: 8 page

Ubik: efficient cache sharing with strict qos for latency-critical workloads

Chip-multiprocessors (CMPs) must often execute workload mixes with different performance requirements. On one hand, user-facing, latency-critical applications (e.g., web search) need low tail (i.e., worst-case) latencies, often in the millisecond range, and have inherently low utilization. On the other hand, compute-intensive batch applications (e.g., MapReduce) only need high long-term average performance. In current CMPs, latency-critical and batch applications cannot run concurrently due to interference on shared resources. Unfortunately, prior work on quality of service (QoS) in CMPs has focused on guaranteeing average performance, not tail latency. In this work, we analyze several latency-critical workloads, and show that guaranteeing average performance is insufficient to maintain low tail latency, because microarchitectural resources with state, such as caches or cores, exert inertia on instantaneous workload performance. Last-level caches impart the highest inertia, as workloads take tens of milliseconds to warm them up. When left unmanaged, or when managed with conventional QoS frameworks, shared last-level caches degrade tail latency significantly. Instead, we propose Ubik, a dynamic partitioning technique that predicts and exploits the transient behavior of latency-critical workloads to maintain their tail latency while maximizing the cache space available to batch applications. Using extensive simulations, we show that, while conventional QoS frameworks degrade tail latency by up to 2.3x, Ubik simultaneously maintains the tail latency of latency-critical workloads and significantly improves the performance of batch applications.United States. Defense Advanced Research Projects Agency (Power Efficiency Revolution For Embedded Computing Technologies Contract HR0011-13-2-0005)National Science Foundation (U.S.) (Grant CCF-1318384