Highly Efficient Ge-Rich Ge<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Pb<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Te Thermoelectric Alloys

The search for alternative energy sources is presently at the forefront of applied research. In this context, thermoelectricity for direct energy conversion from thermal to electrical energy plays an important role. This paper is concerned with the development of highly efficient p-type Ge _x Pb_1−x Te alloys for thermoelectric applications, using spark plasma sintering. The carrier concentration of GeTe was varied by alloying of PbTe and/or by Bi₂Te₃ doping. Very high ZT values up to ~1.8 at 500°C were obtained by doping Pb_0.13Ge_0.87Te with 3 mol% Bi₂Te₃.     

Structural Evolution Following Spinodal Decomposition of the Pseudoternary Compound (Pb0.3Sn0.1Ge0.6)Te

Pseudoternary (Ge,Sn,Pb)Te compounds display favorable thermoelectric properties. Spinodal decomposition in the quasiternary (Ge,Sn,Pb)Te system is at the origin of a wide solubility gap at low Sn concentrations. The structural evolution of the spinodal decomposition was investigated as a function of aging time at 500°C, using x-ray diffraction, electron microscopy, and scanning electron microscopy. The evolution of the structure at 500°C consists initially of a short diffusion-controlled demixing stage into Pb- and Ge-rich coherent areas, with compositions corresponding to the inflection points of the free-energy curve. The Pb-rich areas adopt configurations associated with the directions of the soft elastic moduli of the cubic compound. Both the Pb- and Ge-rich areas are supersaturated and undergo in a second stage a nucleation and growth process and give rise to a biphased structure with equilibrium compositions corresponding to the boundaries of the miscibility gap. The resulting Pb-rich areas display a relatively stable microstructure suggesting the presence of long-range interactions between the Pb-rich precipitates in the Ge-rich matrix.     

The structure and electro‐mechanical properties of novel hybrid CNT/PANI nanocomposites

Electrically conductive elastomeric nanocomposites containing carbon nanotubes (CNT) and polyaniline (PANI) are reported in the present investigation. The synthesis procedure included an in situ inverse emulsion polymerization of aniline doped with dodecylbenzene sulfonic acid (DBSA) in the presence of CNT and dissolved styrene‐isoprene‐styrene (SIS) block copolymer. The PANI synthesis step was carried out by applying ultrasonic energy. The dispersions obtained were processed by two methods: a recently developed precipitation‐filtration procedure, and a conventional drop‐cast procedure. The techniques developed resulted in homogeneous exfoliated PANI coated nanotubes within the elastomeric matrix. The presence of CNT/PANI in the SIS elastomeric matrix affects thermal, mechanical, and electrical properties of the nanocomposites. The formation of continuous three‐dimensional CNT/PANI networks prepared via the precipitation‐filtration method enhances the nanocomposite properties. Contrarily, the intermittent three‐dimensional network prepared by conventional drop‐cast method leads to inferior properties. Nanocomposites produced by both techniques are observed by HRSEM. The two processing techniques result in different structures, which affect the physical properties of the materials produced. A relatively low percolation threshold for both methods was determined. The Young's modulus of the SIS/CNT/PANI significantly increased in the presence of CNT. The precipitation‐filtration technique yields an improved nanocomposite product compared to the drop‐cast route. POLYM. COMPOS., 35:788–794, 2014. © 2013 Society of Plastics Engineers     

Development of a plasma panel muon detector

A radiation detector technology based on plasma display panels (PDPs), the underlying engine of panel plasma television displays, is being investigated. Emerging from this well-established television technology is the Plasma Panel Sensor (PPS), a novel variant of the micro-pattern radiation detector. The PPS is fundamentally a fast, high-resolution detector comprised of an array of plasma discharge cells, operating in a hermetically sealed gas mixture. We report on the PPS development effort, including proof-of-principle results of laboratory signal observations.     

THE SHAPE OF A GAS/LIQUID INTERFACE IN A RECTANGULAR CAVITY ALLOWING FOR AN ARBITRARY DIRECTION OF THE BODY FORCE

A method to calculate the shape of the gas/liquid interface in a rectangular cavity is presented. This article is an expansion of investigations carried out in the 1960s, where the direction of the body force was assumed to be parallel to the side walls of the cavity. In the present work this assumption is eliminated, thus introducing the tilt angle as an additional variable affecting the interface shape. The shape of the interface for several values of Bond number, contact angle, and tilt angle is calculated. A critical Bond number below which the interface shape does not change is identified. The implications to liquid-phase processing in micromachining and microelectronics fabrication are discussed.     

Screen time: Clinical notes regarding Meissner's (2006) chronically late patient.

This communication is a commentary on William W. Meissner's presentation (see record 2006-20697-003) of a patient who chronically came late for sessions. The time duration of analytic work-relatively restricted per hour yet potentially limitless in overall duration-represents an existential paradox that is fundamental to the basic representational qualities of mental experience, and inherent in a mute way in the analytic frame. It is to be expected that the latent temporal elements of the patient's conflicts will inevitably challenge this aspect of the frame, subtly coercing patient and analyst to recreate these novel dimensions. If the analyst is too cautious regarding the inevitability of countertransference reactions to such a patient, important developmental opportunities may be missed. I suspect that the chronic lateness and absence that characterized the work with this patient screened an early, nonmentalized trauma that had torn a hole in the foundations of the patient's sense of time, and was inadvertently expressed by Meissner in an entirely atypical manner. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stochastically bounded burstiness for communication networks

A network calculus is developed for processes whose burstiness is stochastically bounded by general decreasing functions. This calculus is useful for a large class of input processes, including important processes exhibiting “subexponentially bounded burstiness” such as fractional Brownian motion. Moreover, it allows judicious capture of the salient features of real-time traffic, such as the “cell” and “burst” characteristics of multiplexed traffic. This accurate characterization is achieved by setting the bounding function as a sum of exponentials     

Computerization of school administration: impact on the principal’s role—a case study

Changes in the principal’s role, resulting from the computerization of a high-school’s instruction-administration subsystem (i.e. a significant technological change), occurred in six major categories: accountability, instruction evaluation, supervision, feedback, frequency of meetings, and shared decision-making. The principal’s interrelations with department heads, homeroom teachers and teachers, tightened significantly. The principal’s interrelations with the school computer administrator (a new role created as a result of the introduction of a school management information system), were found to be tight and on a daily basis. The results of this research might have significant theoretical and practical implications. They should be related to SMIS impact on schooling in general and on the principal’s role in particular.     

Authorship attribution in the wild

Most previous work on authorship attribution has focused on the case in which we need to attribute an anonymous document to one of a small set of candidate authors. In this paper, we consider authorship attribution as found in the wild: the set of known candidates is extremely large (possibly many thousands) and might not even include the actual author. Moreover, the known texts and the anonymous texts might be of limited length. We show that even in these difficult cases, we can use similarity-based methods along with multiple randomized feature sets to achieve high precision. Moreover, we show the precise relationship between attribution precision and four parameters: the size of the candidate set, the quantity of known-text by the candidates, the length of the anonymous text and a certain robustness score associated with a attribution.