Method of measuring thermal conductivity of high performance insulation

Method accurately measures the thermal conductivity of high-performance sheet insulation as a discrete function of temperature. It permits measurements to be made at temperature drops of approximately 10 degrees F across the insulation and ensures measurement accuracy by minimizing longitudinal heat losses in the system

Fitting EXAFS data using molecular dynamics outputs and a histogram approach

The estimation of metal nanoparticle diameter by analysis of extended x-ray absorption fine structure (EXAFS) data from coordination numbers is nontrivial, particularly for particles <5 nm in diameter, for which the undercoordination of surface atoms becomes an increasingly significant contribution to the average coordination number. These undercoordinated atoms have increased degrees of freedom over those within the core of the particle, which results in an increase in the degree of structural disorder with decreasing particle size. This increase in disorder, however, is not accounted for by the standard means of EXAFS analysis, where each coordination shell is fitted with a single bond length and disorder term. In addition, the surface atoms of nanoparticles have been observed to undergo a greater contraction than those in the core, further increasing the range of bond distances. Failure to account for this structural change results in an increased disorder being measured, and therefore, a lower apparent coordination number and corresponding particle size are found. Here, we employ molecular dynamics (MD) simulations for a range of nanoparticle sizes to determine each of the nearest neighbor bond lengths, which were then binned into a histogram to construct a radial distribution function (RDF). Each bin from the histogram was considered to be a single scattering path and subsequently used in fitting the EXAFS data obtained for a series of carbon-supported platinum nanoparticles. These MD-based fits are compared with those obtained using a standard fitting model using Artemis and the standard model with the inclusion of higher cumulants, which has previously been used to account for the non-Gaussian distribution of neighboring atoms around the absorber. The results from all three fitting methods were converted to particle sizes and compared with those obtained from transmission electron microscopy (TEM) and x-ray diffraction (XRD) measurements. We find that the use of molecular dynamics simulations resulted in an improved fit over both the standard and cumulant models, in terms of both quality of fit and correlation with the known average particle size

Making Open Access Viable Economically

The Editors-in-Chief have decided that we will provide our much-cherished readers with an editorial every so often as a way of sharing insights from the “machine room” where so much of the thinking and work is done to publish the German Law Journal. We want to let you in on the ideas that are on our minds, share with you our observations, and include you in the conversations we are having that might be of interest to you. We begin this tradition with this issue, Volume 21 – Number 6. Andrew Hyde, a member of the editorial team with which the Journal has partnered at Cambridge University Press, as well as Russell A. Miller and Emanuel V. Towfigh, two of the Journal’s co-Editors-in-Chief, open our From the Headquarters Essay with a piece on the Journal’s experiences with and its further plans for making open-access (OA) publishing economically viable. Related to that theme, we also want to share news with you about the introduction of a voluntary article processing charge this fall. Finally, we want to draw your attention to a videos and podcasts service we will start to produce to accompany the scholarship published in the Journal as a way of promoting our authors’ work and expanding access to their ideas. If you are interested only in these latter initiatives, you can also read the short section in the GLJ Instructions for Authors

LMC X-1: A New Spectral Analysis of the O-star in the binary and surrounding nebula

We provide new observations of the LMC X-1 O star and its extended nebula structure using spectroscopic data from VLT/UVES as well as H$\alpha$ imaging from the Wide Field Imager on the Max Planck Gesellschaft / European Southern Observatory 2.2m telescope and ATCA imaging of the 2.1 GHz radio continuum. This nebula is one of the few known to be energized by an X-ray binary. We use a new spectrum extraction technique that is superior to other methods to obtain both radial velocities and fluxes. This provides an updated spatial velocity of $\simeq 21.0~\pm~4.8$ km s$^{-1}$ for the O star. The slit encompasses both the photo-ionized and shock-ionized regions of the nebula. The imaging shows a clear arc-like structure reminiscent of a wind bow shock in between the ionization cone and shock-ionized nebula. The observed structure can be fit well by the parabolic shape of a wind bow shock. If an interpretation of a wind bow shock system is valid, we investigate the N159-O1 star cluster as a potential parent of the system, suggesting a progenitor mass of $\sim 60$ M$_{\odot}$ for the black hole. We further note that the radio emission could be non-thermal emission from the wind bow shock, or synchrotron emission associated with the jet inflated nebula. For both wind and jet-powered origins, this would represent one of the first radio detections of such a structure.Comment: 7 Figures, 4 Table

Donor tricuspid annuloplasty during orthotopic heart transplantation: Long-term results of a prospective controlled study

Background: Development of tricuspid regurgitation after orthotopic heart transplantation can cause heart failure along with renal and hepatic impairment and portends a poor prognosis. If tricuspid regurgitation causes significant symptoms, tricuspid valve repair or replacement is often required. This study was designed to study the effects of prophylactic tricuspid valve annuloplasty (TVA) during orthotopic heart transplantation on long-term survival, renal function, and amount of tricuspid regurgitation. Methods: Between April 1997 and March 1998, 60 patients (aged 18 to 70 years; 22 female) randomly received either standard bicaval orthotopic heart transplantation (group STD; n = 30) or bicaval orthotopic heart transplantation with DeVega TVA (group TVA; n = 30). Tricuspid valve annuloplasty was performed on the donor heart before implantation using pledgeted 2-0 polypropylene and sized to an annulus of 29 mm. Echocardiographic measurements, laboratory values, and hemodynamics were obtained prospectively and reviewed by an independent data analyst. Results: Follow-up of patients as of December 2003 was complete. Although there was a perioperative mortality advantage in group TVA, there was no difference between groups in long-term survival. At the end of the study, however, there was a statistical difference (group STD versus group TVA, p \u3c 0.05) with regard to cardiac mortality (7 of 30 versus 3 of 30), average amount of tricuspid regurgitation (1.5 ± 1.3 versus 0.5 ± 0.4), percentage of patients with 2+ or greater tricuspid regurgitation (34% versus 0%), serum creatinine (2.9 ± 2.0 versus 1.8 ± 0.7), and difference in serum creatinine over baseline (2.0 ± 2.1 versus 0.7 ± 0.8). Conclusions: Prophylactic DeVega TVA of the donor heart is durable and decreases the incidence of cardiac-related mortality and tricuspid regurgitation after orthotopic heart transplantation. In addition, there is improved protection of renal function. Considering the ease and safety of TVA and its advantages, it should be performed as a routine adjunct to orthotopic heart transplantation

Code Assesses Risks Posed by Meteoroids and Orbital Debris

BUMPER II version 1.92e is a computer code for assessing the risk of damage from impacts of micrometeoroids and orbital debris on the International Space Station (ISS), including those parts of the ISS covered by shielding that affords partial protection against such impacts. (Other versions of BUMPER II have been written for other spacecraft.) Bumper II quantifies the probability of penetration of shielding and the damage to spacecraft equipment as functions of the size, shape, and orientation of the spacecraft; the parameters of its orbit; failure criteria that quantify impact damage at the threshold of failure for each spacecraft surface; and the impact-damage resistance of each spacecraft surface as defined by "ballistic limit equations" that return the size of a failure-causing particle as a function of target parameters (including materials, configurations, thicknesses, and gap distances) and impact conditions (impact velocity and the density and shape of the impactor). BUMPER II version 1.92e contains several dozen ballistic limit equations that are based on results from thousands of hypervelocity impact tests conducted by NASA on ISS shielding and other hardware, and on results from numerical simulations of impacts