High temperature thermoelectric efficiency in Ba8Ga16Ge30

The high thermoelectric figure of merit (zT) of Ba8Ga16Ge30 makes it one of the best n-type materials for thermoelectric power generation. Here, we describe the synthesis and characterization of a Czochralski pulled single crystal of Ba8Ga16Ge30 and polycrystalline disks. Measurements of the electrical conductivity, Hall effect, specific heat, coefficient of thermal expansion, thermal conductivity, and Seebeck coefficient were performed up to 1173 K and compared with literature results. Dilatometry measurements give a coefficient of thermal expansion of 16×10^−6 K^−1 up to 1175 K. The trend in electronic properties with composition is typical of a heavily doped semiconductor. The maximum in the thermoelectric figure of merit is found at 1050 K with a value of 0.8. The correction of zT due to thermal expansion is not significant compared to the measurement uncertainties involved. Comparing the thermoelectric efficiency of segmented materials, the effect of compatibility makes Ba8Ga16Ge30 more efficient than the higher zT n-type materials SiGe or skutterudite CoSb3

The Top Triangle Moose

We introduce a deconstructed model that incorporates both Higgsless and top-color mechanisms. The model alleviates the typical tension in Higgsless models between obtaining the correct top quark mass and keeping delta-rho small. It does so by singling out the top quark mass generation as arising from a Yukawa coupling to an effective top-Higgs which develops a small vacuum expectation value, while electroweak symmetry breaking results largely from a Higgsless mechanism. As a result, the heavy partners of the SM fermions can be light enough to be seen at the LHC.Comment: To appear in proceedings of SCGT09, Nagoya, Japan. 5 page

THE EFFECTS ON STRENGTH, POWER, AND GENU VALGUM FOLLOWING A FIVE WEEK TRAINING PROGRAM WITH WHOLE-BODY VIBRATION

Human movements are controlled by the motor and sensory command centers of the body, and evidence indicates that voluntary activation of muscles is limited in force, power, and strength production (Ronnestad, 2004). The increase of motor unit activation through whole-body vibration (WBV) allows the muscles to contract and relax at a higher rate utilizing more muscle fibers to enhance athletic performance. The purpose is to examine the effects on strength, power, and genu valgum angle following a five week resistance training program either with or without whole-body vibration

THE EFFECTS OF ACUTE WHOLE-BODY VIBRATION ON MAXIMAL COUNTERMOVEMENT VERTICAL JUMP IN RECREATIONALLY ACTIVE MALES AND FEMALES

Performance is a key factor in any type of training and competition, and even the smallest improvement can have a profound effect on the overall outcome. Some studies have shown that acute whole body vibration elicits a rapid increase in intra-muscular temperature and muscle contraction, thereby enhancing power, strength, and overall performance in the short-term (Cochrane, Stannard, Firth, & Rittweger, 2010). The purpose of this study was to examine the acute effects of three sets of 30 second body weight squats with and without whole-body vibration on maximal countermovement vertical jump in recreationally active males and females

Differential Very Long Baseline Interferometry (delta VLBI) spacecraft tracking system demonstration. Part 2: Data acquisition and processing

A set of experiments in the use of Differential Very Long Baseline Interferometry (delta VLBI) for spacecraft navigation were completed. Data using both Voyager spacecraft and a single quasar were acquired during the Jupiter encounter time period. The data were processed and analyzed to assess the navigation accuracy of delta VLBI. The data reduction and techniques for assessing data quality and consistency are discussed

Casimir energy density in closed hyperbolic universes

The original Casimir effect results from the difference in the vacuum energies of the electromagnetic field, between that in a region of space with boundary conditions and that in the same region without boundary conditions. In this paper we develop the theory of a similar situation, involving a scalar field in spacetimes with compact spatial sections of negative spatial curvature.Comment: 10 pages. Contribution to the "Fifth Alexander Friedmann International Seminar on Gravitation and Cosmology," Joao Pessoa, Brazil, 2002. Revised version, with altered Abstract and one new referenc

Paper Session II-B - The Selection of a Launch Vehicle

The selection of a launch vehicle should not depend on any single vehicle attribute (i.e., price, reliability, availability, insurance rate, final payload placement accuracy, etc.), but rather on the effect of the interaction of multiple vehicle attributes in combination with payload configuration and sparing/maintenance strategy. For commercial organizations, selection decisions should be based on performance measures such as ROI and risk. For government operations, selections should be based on measures such as present value of life cycle cost in combination with availability constraints. Methods for analyzing launch vehicle and related choices are described together with parametric results illustrating important tradeoffs

Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice

We demonstrate preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance $-14$ dB below the Poissonian noise level. A mesoscopic ensemble containing a few thousand atoms is trapped in the evanescent field of a nanofiber. The atom number is measured through dual-color homodyne interferometry with a pW-power shot noise limited probe. Strong coupling of the evanescent probe guided by the nanofiber allows for a real-time measurement with a precision of $\pm 8$ atoms on an ensemble of some $10^3$ atoms in a one-dimensional trap. The method is very well suited for generating collective atomic entangled or spin-squeezed states via a quantum non-demolition measurement as well as for tomography of exotic atomic states in a one-dimensional lattice