Interconnect fatigue design for terrestrial photovoltaic modules

The results of comprehensive investigation of interconnect fatigue that has led to the definition of useful reliability-design and life-prediction algorithms are presented. Experimental data indicate that the classical strain-cycle (fatigue) curve for the interconnect material is a good model of mean interconnect fatigue performance, but it fails to account for the broad statistical scatter, which is critical to reliability prediction. To fill this shortcoming the classical fatigue curve is combined with experimental cumulative interconnect failure rate data to yield statistical fatigue curves (having failure probability as a parameter) which enable (1) the prediction of cumulative interconnect failures during the design life of an array field, and (2) the unambiguous--ie., quantitative--interpretation of data from field-service qualification (accelerated thermal cycling) tests. Optimal interconnect cost-reliability design algorithms are derived based on minimizing the cost of energy over the design life of the array field

The Chandra Dust Scattering Halo of Galactic Center transient Swift J174540.7-290015

We report the detection of a dust scattering halo around a recently discovered X-ray transient, Swift J174540.7-290015, which in early February of 2016 underwent one of the brightest outbursts (F_X ~ 5e-10 erg/cm^2/s) observed from a compact object in the Galactic Center field. We analyze four Chandra images that were taken as follow-up observations to Swift discoveries of new Galactic Center transients. After adjusting our spectral extraction for the effects of detector pileup, we construct a point spread function for each observation and compare it to the GC field before the outburst. We find residual surface brightness around Swift J174540.7-290015, which has a shape and temporal evolution consistent with the behavior expected from X-rays scattered by foreground dust. We examine the spectral properties of the source, which shows evidence that the object transitioned from a soft to hard spectral state as it faded below L_X ~ 1e36 erg/s. This behavior is consistent with the hypothesis that the object is a low mass X-ray binary in the Galactic Center.Comment: Accepted for publication in Ap

Thermodynamics predicts how confinement modifies hard-sphere dynamics

We study how confining the equilibrium hard-sphere fluid to restrictive one- and two-dimensional channels with smooth interacting walls modifies its structure, dynamics, and entropy using molecular dynamics and transition-matrix Monte Carlo simulations. Although confinement strongly affects local structuring, the relationships between self-diffusivity, excess entropy, and average fluid density are, to an excellent approximation, independent of channel width or particle-wall interactions. Thus, thermodynamics can be used to predict how confinement impacts dynamics.Comment: 4 pages, 4 figure

Estructura, fábrica magnética y emplazamiento de los granitos de Brealito y La Paya, basamento del valle Calchaquí, Salta, Argentina

Los granitoides de Brealito y La Paya son plutones de formas elípticas alargadas en dirección N-S emplazados respectivamente en las Formaciones Puncoviscana y La Paya. El estudio de la estructura interna de los plutones se ha abordado aplicando la anisotropía de la susceptibilidad magnética (ASM). El plutón de La Paya presenta un carácter paramagnético (K entre 1,9 y 6,7 x10- 5 SI) con una fábrica magnética controlada por la biotita, en cambio el plutón de Brealito muestra un carácter mixto (K entre 22 y 466 x10- 5 SI) con algunas estaciones en las que la contribución ferromagnética (originada por magnetita) es dominante. Las anisotropías totales medidas son coherentes con el carácter magmático de las muestras analizadas. Ambos plutones presentan semejanzas desde el punto de vista estructural. Son cuerpos de forma lenticular, concordantes con el encajante y buzando hacia el Oeste. La lineación magnética presenta buzamientos suaves en dirección N-S.The Brealito and La Paya granitoids are elliptical-shaped plutons with N-S elongation. They intrude into the Puncoviscana and La Paya Formations, respectively. The internal structure of these plutons has been studied by using field structures and applying the Anisotropy of the Magnetic Susceptibility (AMS). The magnetic fabric of the La Paya pluton reflects the orientation of biotite, the main paramagnetic mineral in this granite (K between 1.9 and 6.7 x10-5SI). Instead, the magnetic behavior of the Brealito granite is more complex since not only paramagnetic minerals, but also the ferromagnetic contribution (K between 22 and 466 x10-5SI) of magnetite crystals strongly control the magnetic fabric of some samples. Total anisotropy values of the magnetic fabrics are coherent with the magmatic nature of the analized samples. From the structural point of view, both plutons display similarities. These granites are lozenge-shaped bodies concordant with the host rocks. Their planar fabrics are mainly NS-trending and West dipping, and magnetic lineations plunge at low angles along the N-S direction

Monte Carlo Renormalization Group Analysis of Lattice ϕ4\phi^4 Model in D=3,4D=3,4

We present a simple, sophisticated method to capture renormalization group flow in Monte Carlo simulation, which provides important information of critical phenomena. We applied the method to $D=3,4$ lattice $\phi^4$ model and obtained renormalization flow diagram which well reproduces theoretically predicted behavior of continuum $\phi^4$ model. We also show that the method can be easily applied to much more complicated models, such as frustrated spin models.Comment: 13 pages, revtex, 7 figures. v1:Submitted to PRE. v2:considerably reduced redundancy of presentation. v3:final version to appear in Phys.Rev.

Roman mining on Exmoor: a geomorphological approach at Anstey's Combe, Dulverton

A survey of valley fills in south-facing combes (headwater valleys) along the south side of the Exmoor massif revealed an anomalously deep infill in one valley. This infill of up to 5 m depth had been gullied revealing a complex stratigraphy. Studies of the stratigraphy, clast orientation and shape suggested several accumulation episodes under different environmental conditions commencing in a periglacial climatic regime. Later units included sandy silts which can be dated using optically stimulated luminescence (OSL) of quartz grains. The OSL dates, indicate that the inter-gravel silts accumulated in two periods, the Romano-British period and the 16th-17th centuries AD. A survey of the very small valley catchment revealed a linear trench of a type associated with early iron mining. Given the anomalously high volume of accumulated sediment from such a small catchment and evidence of mining on the slope above the site, the geomorphic mechanism is almost certainly the downslope transport of mining debris from the slope to the valley floor. This study suggests that the systematic survey of headwater valleys in metalliferous uplands may be one way of locating areas of early mining activity and that such deposits could provide a chronology of working and abandonment

Profile and width of rough interfaces

In the context of Landau theory and its field theoretical refinements, interfaces between coexisting phases are described by intrinsic profiles. These intrinsic interface profiles, however, are neither directly accessible by experiment nor by computer simulation as they are broadened by long-wavelength capillary waves. In this paper we study the separation of the small scale intrinsic structure from the large scale capillary wave fluctuations in the Monte Carlo simulated three-dimensional Ising model. To this purpose, a blocking procedure is applied, using the block size as a variable cutoff, and a translationally invariant method to determine the interface position of strongly fluctuating profiles on small length scales is introduced. While the capillary wave picture is confirmed on large length scales and its limit of validity is estimated, an intrinsic regime is, contrary to expectations, not observed.Comment: 18 pages, 4 Postscript figures, LaTeX2e, formulation of sec.3.2 improved, 1 reference adde

Vortex structure and resistive transitions in high-Tc superconductors

The nature of the resistive transition for a current applied parallel to the magnetic field in high-Tc materials is investigated by numerical simulation on the three dimensional Josephson junction array model. It is shown by using finite size scaling that for samples with disorder the critical temperature Tp for the c axis resistivity corresponds to a percolation phase transition of vortex lines perpendicularly to the applied field. The value of Tp is higher than the critical temperature for j perpendicular to H, but decreases with the thickness of the sample and with anisotropy. We predict that critical behavior around Tp should reflect in experimentally accessible quantities, as the I-V curves.Comment: 8 pages + 6 figure

Magnetization Jump in a Model for Flux Lattice Melting at Low Magnetic Fields

Using a frustrated XY model on a lattice with open boundary conditions, we numerically study the magnetization change near a flux lattice melting transition at low fields. In both two and three dimensions, we find that the melting transition is followed at a higher temperature by the onset of large dissipation associated with the zero-field XY transition. It is characterized by the proliferation of vortex-antivortex pairs (in 2D) or vortex loops (in 3D). At the upper transition, there is a sharp increase in magnetization, in qualitative agreement with recent local Hall probe experiments.Comment: updated figures and texts. new movies available at http://www.physics.ohio-state.edu:80/~ryu/jj.html. Accepted for publication in Physical Review Letter

The effect of distance on reaction time in aiming movements

Target distance affects movement duration in aiming tasks but its effect on reaction time (RT) is poorly documented. RT is a function of both preparation and initiation. Experiment 1 pre-cued movement (allowing advanced preparation) and found no influence of distance on RT. Thus, target distance does not affect initiation time. Experiment 2 removed pre-cue information and found that preparing a movement of increased distance lengthens RT. Experiment 3 explored movements to targets of cued size at non-cued distances and found size altered peak speed and movement duration but RT was influenced by distance alone. Thus, amplitude influences preparation time (for reasons other than altered duration) but not initiation time. We hypothesise that the RT distance effect might be due to the increased number of possible trajectories associated with further targets: a hypothesis that can be tested in future experiments