Cyclopropenoid Fatty Acids of Sterculia Oils by Gas Liquid Chromatography

Silver nitrate treated methyl esters of the seed oils of Sterculia alata, Sterculia foetida, Sterculia guttata and Sterculia villosa were subjected to gas liquid chromatography and were found to contain sterculic and malvalic acids (4.0, 17.6; 55.7, 11.4; 5.8, 2.1 and 3.2, 2.5%, respectively), besides the conventional fatty acids. IR and NMR of the oils confirmed the cyclopropenoid moiety in these oils. Seed oil of Sterculia foetida was used as a standard reference.     

Multiple urethral calculi in children: report of two cases

Multiple urethral calculi are rarely found in children. We report herein two unusual cases of children found to have multiple urethral calculi. In one, the calculi formed proximal to a stricture and in the other they formed within a diverticulum. Both patients required urethrotomy for removal of the calculi. A unique cause of urethral stricture is also described in case 1.     

SiC fibre by chemical vapour deposition on tungsten filament

A CVD system for the production of continuous SiC fibre was set up. The process of SiC coating on 19 μ m diameter tungsten substrate was studied. Methyl trichloro silane (CH₃SiCl₃) and hydrogen reactants were used. Effect of substrate temperature (1300–1500°C) and concentration of reactants on the formation of SiC coating were studied. SiC coatings of negligible thickness were formed at very low flow rates of hydrogen (5 × 10⁻⁵ m³/min) and CH₃SiCl₃ (1.0 × 10⁻⁴ m³/min of Ar). Uneven coatings and brittle fibres were formed atvery high concentrations of CH₃SiCl₃ (6 × 10⁻⁴ m³/min of Ar). The flow rates of CH₃SiCl₃ and hydrogen were adjusted to get SiC fibre with smooth surface. The structure and morphology of SiC fibres were evaluated.     

A second ceramic age—A new materials frontier

A second ceramic age started in the mid-twentieth century as a new, exciting materials frontier. Electroceramics with phenomenally wide range of electrical resistivity (spread over 30 orders of magnitude) span insulators, semiconductors, metal-like conductors, ionic conductors, and, recently, superconductors. They also include ferroelectrics, piezoelectrics, pyroelectrics and electro-optics beside ferrites. Advances in electroceramics have been fascinating and rapid, leading to unprecedented rates of industrial growth. Age-old limitations of poor mechanical strength and brittleness of ceramics are being overcome by outstanding toughness and strength achieved in zirconiabased ceramics exploiting the martensitic transformation at the tetragonal-monoclinic phase change. The dimensional changes at this transition which prevented the use of zirconia earlier has now been turned into a mechanism for toughening ceramics to significant levels. Ceramics with near-zero overall thermal expansion coefficient offer new opportunities to science and industry. Distinguished Materials Scientist of the Year Award Lecture presented at the MRSI meeting, New Delhi, on February 9, 1991. Professor E C Subbarao, born on 8 August 1928 in Narsapur, Andhra Pradesh received his B.Sc. Tech degree in Glass Technology from Banaras Hindu University, Varanasi in 1949, his B.S. and M.S. degrees in Ceramic Engineering from the University of Washington, Seattle, WA, USA in 1952 and 1953 and his Ph.D. degree in Ceramic Technology from the Pennsylvania State University, University Park, PA, USA in 1957. He was employed by the Parry and Co. Ltd., Ranipet, TN from 1949 to 1951 and as a Research and Fellow Engineer by Westinghouse Research Laboratories, Pittsburgh, Pa, USA from 1956 to 1963. Joining the Metallurgical Engineering Department of the Indian Institute of Technology, Kanpur in 1963 as an Associate Professor, he continued as a Professor from 1964 to 1981. He is the Founder-Director of the Tata Research Development and Design Centre, Pune since 1981. At IIT, Kanpur, he organised the Metallurgical Engineering Department as its first Head from 1963 to 1967 and the Inter-disciplinary Program in Materials Science as its first Convenor from 1971 to 1975. He was also the first Dean of Faculties at IIT, Kanpur from 1966 to 1972. Professor Subbarao published or edited nine books and published over 140 papers. He was elected a Fellow of the Indian National Science Academy, the Indian Academy of Sciences, the Indian Institute of Ceramics, and the (International) Academy of Ceramics. He has been awarded the National Metallurgists Award, the Homi Bhabha Award in Applied Science, and the Varshnei Memorial Award.     

Gyrokinetic particle-in-cell optimization on emerging multi- and manycore platforms

The next decade of high-performance computing (HPC) systems will see a rapid evolution and divergence of multi- and manycore architectures as power and cooling constraints limit increases in microprocessor clock speeds. Understanding efficient optimization methodologies on diverse multicore designs in the context of demanding numerical methods is one of the greatest challenges faced today by the HPC community. In this work, we examine the efficient multicore optimization of GTC, a petascale gyrokinetic toroidal fusion code for studying plasma microturbulence in tokamak devices. For GTC’s key computational components (charge deposition and particle push), we explore efficient parallelization strategies across a broad range of emerging multicore designs, including the recently-released Intel Nehalem-EX, the AMD Opteron Istanbul, and the highly multithreaded Sun UltraSparc T2+. We also present the first study on tuning gyrokinetic particle-in-cell (PIC) algorithms for graphics processors, using the NVIDIA C2050 (Fermi). Our work discusses several novel optimization approaches for gyrokinetic PIC, including mixed-precision computation, particle binning and decomposition strategies, grid replication, SIMDized atomic floating-point operations, and effective GPU texture memory utilization. Overall, we achieve significant performance improvements of 1.3-4.7× on these complex PIC kernels, despite the inherent challenges of data dependency and locality. Our work also points to several architectural and programming features that could significantly enhance PIC performance and productivity on next-generation architectures.     

Interaction-aware scheduling of report-generation workloads

The typical workload in a database system consists of a mix of multiple queries of different types that run concurrently. Interactions among the different queries in a query mix can have a significant impact on database performance. Hence, optimizing database performance requires reasoning about query mixes rather than considering queries individually. Current database systems lack the ability to do such reasoning. We propose a new approach based on planning experiments and statistical modeling to capture the impact of query interactions. Our approach requires no prior assumptions about the internal workings of the database system or the nature and cause of query interactions, making it portable across systems. To demonstrate the potential of modeling and exploiting query interactions, we have developed a novel interaction-aware query scheduler for report-generation workloads. Our scheduler, called QShuffler, uses two query scheduling algorithms that leverage models of query interactions. The first algorithm is optimized for workloads where queries are submitted in large batches. The second algorithm targets workloads where queries arrive continuously, and scheduling decisions have to be made online. We report an experimental evaluation of QShuffler using TPC-H workloads running on IBM DB2. The evaluation shows that QShuffler, by modeling and exploiting query interactions, can consistently outperform (up to 4x) query schedulers in current database systems.     

Optimizing Recursive Information Gathering Plans in EMERAC

In this paper we describe two optimization techniques that are specially tailored for information gathering. The first is a greedy minimization algorithm that minimizes an information gathering plan by removing redundant and overlapping information sources without loss of completeness. We then discuss a set of heuristics that guide the greedy minimization algorithm so as to remove costlier information sources first. In contrast to previous work, our approach can handle recursive query plans that arise commonly in the presence of constrained sources. Second, we present a method for ordering the access to sources to reduce the execution cost. This problem differs significantly from the traditional database query optimization problem as sources on the Internet have a variety of access limitations and the execution cost in information gathering is affected both by network traffic and by the connection setup costs. Furthermore, because of the autonomous and decentralized nature of the Web, very little cost statistics about the sources may be available. In this paper, we propose a heuristic algorithm for ordering source calls that takes these constraints into account. Specifically, our algorithm takes both access costs and traffic costs into account, and is able to operate with very coarse statistics about sources (i.e., without depending on full source statistics). Finally, we will discuss implementation and empirical evaluation of these methods in Emerac, our prototype information gathering system.     

A facile route for synthesis of long-chain RAC-1-S-alkylglycerols

Alkyl allyl thioethers were prepared by reaction of longchain primary thiols in hexane with allyl bromide in the presence of a phase transfer catalyst (tetrabutylammonium bromide), and aqueous alkali and were hydroxylated to rac-1-S-alkylglycerols by means of a novel reagent, cetyltrimethylammonium permanganate, in dichloromethane.