Heat pipes for wing leading edges of hypersonic vehicles

Wing leading edge heat pipes were conceptually designed for three types of vehicle: an entry research vehicle, aero-space plane, and advanced shuttle. A full scale, internally instrumented sodium/Hastelloy X heat pipe was successfully designed and fabricated for the advanced shuttle application. The 69.4 inch long heat pipe reduces peak leading edge temperatures from 3500 F to 1800 F. It is internally instrumented with thermocouples and pressure transducers to measure sodium vapor qualities. Large thermal gradients and consequently large thermal stresses, which have the potential of limiting heat pipe life, were predicted to occur during startup. A test stand and test plan were developed for subsequent testing of this heat pipe. Heat pipe manufacturing technology was advanced during this program, including the development of an innovative technique for wick installation

Serum eosinophil cationic protein (S-ECP) in a population with low prevalence of atopy

AbstractThe study is a part of the European Community Respiratory Health Survey. A random sample (n=351) of 20–44-year olds and persons of the same age with asthma-like symptoms or current asthma medication according to a postal questionnaire (n=95) were studied. Interview was taken, methacholine challenge was done and ECP, total and specific IgE were measured from serum. The median S-ECP value was 8.0 μg/l in the random sample. The geometric mean of S-ECP was higher in subjects with, than without atopy (10.2. vs 8.9 μg/l, P<0.01) and in subjects with bronchial hyperresponsiveness (BHR) than in subjects without BHR (9.9 vs 8.0 μg/l,P <0.01). The levels correlated weakly to forced expiratory volume in one second (FEV1) (r=0.13, P<0.01) and were not independently correlated with respiratory symptoms, asthma or FEV1 after adjusting for BHR, IgE, sensitisation and smoking. Our results indicate that the level of eosinophil activation is low in a population with a low prevalence of atopy, even when BHR is common

Primary malignant melanoma of breast: A unique case report

Malignant melanoma is a clinical entity that occurs commonly in the skin, mucous membrane, and choroid; its occurrence in breast tissue is extremely rare. Evidence suggests that most malignant melanoma cases present as a metastatic manifestation of primary cutaneous melanoma. It is rare to find primary malignant melanoma of breast tissue. There is a dearth of data on this topic in the academic literature; moreover, there are no standard guidelines or consensus statements available on the management of primary malignant melanoma of the breast. Therefore, we, herein, report one such rare case of malignant melanoma with breast as its primary site

Two-Stage Block Orthogonalization to Improve Performance of ss-step GMRES

On current computer architectures, GMRES' performance can be limited by its communication cost to generate orthonormal basis vectors of the Krylov subspace. To address this performance bottleneck, its $s$-step variant orthogonalizes a block of $s$ basis vectors at a time, potentially reducing the communication cost by a factor of $s$. Unfortunately, for a large step size $s$, the solver can generate extremely ill-conditioned basis vectors, and to maintain stability in practice, a conservatively small step size is used, which limits the performance of the $s$-step solver. To enhance the performance using a small step size, in this paper, we introduce a two-stage block orthogonalization scheme. Similar to the original scheme, the first stage of the proposed method operates on a block of $s$ basis vectors at a time, but its objective is to maintain the well-conditioning of the generated basis vectors with a lower cost. The orthogonalization of the basis vectors is delayed until the second stage when enough basis vectors are generated to obtain higher performance. Our analysis shows the stability of the proposed two-stage scheme. The performance is improved because while the same amount of computation as the original scheme is required, most of the communication is done at the second stage of the proposed scheme, reducing the overall communication requirements. Our performance results with up to 192 NVIDIA V100 GPUs on the Summit supercomputer demonstrate that when solving a 2D Laplace problem, the two-stage approach can reduce the orthogonalization time and the total time-to-solution by the respective factors of up to $2.6\times$ and $1.6\times$ over the original $s$-step GMRES, which had already obtained the respective speedups of $2.1\times$ and $1.8\times$ over the standard GMRES. Similar speedups were obtained for 3D problems and for matrices from the SuiteSparse Matrix Collection.Comment: Accepted for publication in IPDPS'2