GigaE PM: a high performance communication facility using a Gigabit Ethernet

A high performance communication facility, called theGigaE PM, has been designed and implemented for parallel applications on clusters of computers using a Gigabit Ethernet. The GigaE PM provides not only a reliable high bandwidth and low latency communication, but also supports existing network protocols such as TCP/IP. A reliable communication mechanism for a parallel application is implemented on the firmware on a NIC while existing network protocols are handled by an operating system kernel. A prototype system has been implemented using an Essential Communications Gigabit Ethernet card. The performance results show that a 58.3 μs round trip time for a four byte user message, and 56.7 MBytes/sec bandwidth for a 1,468 byte message have been achieved on Intel Pentium II 400 MHz PCs. We have implemented MPICH-PM on top of the GigaE PM, and evaluated the NAS parallel benchmark performance. The results show that the IS class S performance on the GigaE PM is 1.8 times faster than that on TCP/IP. Shinji Sumimoto: He is a Senior Researcher of Parallel and Distributed System Software Laboratory at Real World Computing Partnership, JAPAN. He received BS degree in electrical engineering from Doshisha University. His research interest include parallel and distributed systems, real-time systems, and high performance communication facilities. He is a member of Information Processing Society of Japan. Hiroshi Tezuka: He is a Senior Researcher of Parallel and Distributed System Software Laboratory at Real World Computing Partnership, JAPAN. His research interests include real-time systems and operating system kernel. He is a member of the Information Processing Society of Japan, and Japan Society for Software Science and Technology. Atsushi Hori, Ph.D.: He is a Senior Researcher of Parallel and Distributed System Software Laboratory at Real World Computing Partnership, JAPAN. His current research interests include parallel operating system. He received B.S. and M.S. degrees in Electrical Engineering from Waseda University, and received Ph.D. from the University of Tokyo. He worked as a researcher in Mitsubishi Research Institute from 1981 to 1992. Hiroshi Harada: He is a Senior Researcher of Parallel and Distributed System Software Laboratory at Real World Computing Partnership, JAPAN. His research interests include distributed/parallel systems and distributed shared memory. He received BS degree in physics from Science University of Tokyo. He is a member of ACM and Information Processing Society of Japan. Toshiyuki Takahashi: He is a Researcher at Real World Computing Partnership since 1998. He received his B.S. and M.S. from the Department of Information Sciences of Science University of Tokyo in 1993 and 1995. He was a student of the Information Science Department of the University of Tokyo from 1995 to 1998. His current interests are in meta-level architecture for programming languages and high-performance software technologies. He is a member of Information Processing Society of Japan. Yutaka Ishikawa, Ph.D.: He is the chief of Parallel and Distributed System Software Laboratory at Real World Computing Partnership, JAPAN. He is currently temporary retirement from Electrotechnical Laboratory, MITI. His research interests include distributed/parallel systems, object-oriented programming languages, and real-time systems. He received the B.S., M.S. and Ph.D degrees in electrical engineering from Keio University. He is a member of the IEEE Computer Society, ACM, Information Processing Society of Japan, and Japan Society for Software Science and Technology.     

Catalytic Properties of Ni3Al Foils for Methanol Decomposition

Hydrogen was produced by methanol decomposition over cold-rolled foils of intermetallic compound Ni₃Al which is known as an excellent high-temperature structural material. We found high catalytic activity and selectivity for methanol decomposition in flat cold-rolled Ni₃Al foils. The catalytic activity was enhanced above 713 K by the spontaneous formation of fine Ni particles dispersed on carbon nanofibers during the reaction, resulting in high catalytic performance. The results demonstrate that the Ni₃Al foils can be used both as catalyst precursors and as structural materials of microreactors for hydrogen production.     

Builder performance in detergent formulations and biodegradability of partially dicarboxylated cellulose and amylose containing sugar residues in the backbone

Poly(sodium carboxylate)s containing varying amounts of unreacted sugar residues as biodegradable segments in the polymer backbone were prepared by the partial oxidation of amylose and cellulose using periodic acid/chlorite. It was found that dicarboxy polysaccharides containing sugar residues showed improved biodegradability comparing to those having no sugar blocks in the polymer chain, and their biodegradability varied according to the glucopyranose content or the degree of dicarboxylation. Dicarboxy polysaccharides containing more than 60% glucopyranose residues tended to biodegrade quickly. When compared on an equal glucopyranose content basis, the biodegradability of dicarboxy amylose (2b) was slightly superior to that of dicarboxy cellulose (2a) . The builder performance in detergents was dependent on the degree of dicarboxylation, and a clear relation between the detergency and the content of carboxylate groups was observed. Dicarboxy polysaccharides with more than 40% dicarboxylation showed better builder performance than those of disodium 3-oxapentanedioate and trisodium citrate, with some of them superior to that of sodium tripolyphosphate (STPP). The detergency of 2b was more effective than that of 2a . It was also found that the detergency was improved much by increasing the amount of polymeric builder.     

Carbonization behavior of hydrogenated ethylene tar pitch

Carbonization behavior of ethylene tar pitch has been studied with respect to mesophase formation by means of modification of the chemical composition of the starting materials. The hydrogen treatment of ethylene tar pitch has been carried out over the temperature range from 473 to 673 K under a pressure of 10 MPa without catalyst. Then, the hydrogenated ethylene tar pitches were carbonized at 723 K and the optical texture of the resultant cokes were assesed by optical microscopy. It was revealed that the carbonization of the ethylene tar pitch hydrogenated at 673 K gives a coke of optical texture with enlarged flow-domain. The hydrogen-transfer ability of the ethylene tar pitches during the temperature range of mesophase formation was estimated by the method of 9,10 dihydroanthracene (DHA) formation through co-carbonization of the pitch with anthracene. It was recognized that the larger the amount of conversion of DHA, the better is the development of optical texture.     

Synthesis of polymer materials by low energy electron beam. III. Effects of polymerization temperature in EB solid-state polymerization of semicrystalline urethane-acrylate film

In an electron beam (EB) polymerization of a urethane-acrylate prepolymer, the polymerization temperature greatly affected the structure and properties of the resulting gel film. Urethaneacrylate, which was synthesized by the reaction of poly(butylene adipate)diol, 4,4′-diphenylmethane diisocyanate, and 2-hydroxyethyl acrylate, was used as a prepolymer. The prepolymer was semicrystalline and showed a melting point in the region of 50–60°C. The maximum polymerization rate of the prepolymer was obtained when the prepolymer film was irradiated in the temperature range of 25–40°C. EB polymerization below the melting point (T_m) of the prepolymer produced semicrystalline polyurethane-acrylate gel films with a spherulitic texture. On the other hand, EB polymerization above the T_m destroyed the crystalline phase of the prepolymer to give transparent gel films. The gel film cured below the T_m had higher stress at yield, Young's modulus, and tensile strength than those cured above the T_m. Such temperature effects are attributed to whether or not the EB polymerization proceeds with retention of crystalline structure of the prepolymer.     

A Stress Analysis of Butt Adhesive Joints Under Torsional Loads

The stress distribution and the displacement are examined when a butt adhesive joint, in which two dissimilar tubular shafts are joined, is subjected to a torsional load. In the analyses, general representations of the stresses and the displacements are given as a torsion problem when two dissimilar tubular shafts are band-adhesively bonded. Next, in the case of shafts with the same material, effects of the ratio of the shear modulus of an adhesive to that of shafts, the thickness of the adhesive and the bonded position of band-adhesive on the stress distribution are made clear by numerical computations. Moreover, when solid shafts are joined, these effects are made clear by the similar analyses and numerical computations.     

Plasma surface treatments of melt‐extruded sheets of poly(L‐lactic acid)

Poly(L‐lactic acid) sheets, prepared by melt extrusion, were treated with O₂?, He?, and N₂?plasmas generated in radio frequency (RF) at 13.56 MHz. Atmospheric pressure discharge at 20 kHz in helium was also applied to the modification of the sheets. The surface of the PLLA sheets was etched to form the characteristic morphology, and the patterns were different depending on the type of plasma. Polar groups composed of –COOH and –OH were incorporated by plasma treatment, and the surface became wettable. Surface modification became effective after a short treatment period, e.g., 30 seconds. Receding contact angles (θ_r) changed remarkably, and the surface properties were closely related to the increase in the surface energy of the polar contribution (γ_s^p). Biodegradation of the poly(L‐lactic acid) sheets was not enhanced practically, even though the surface became hydrophilic after plasma treatment.     

Stress Analysis of T-type Butt Adhesive Joint Subjected to External Bending Moments

Stress distributions and displacements at the interface between an adhesive and an adherend are examined when a T-type butt adhesive joint, in which two thin plates are joined, is subjected to an external bending moment. In the analyses, general representations of the stresses and the displacements are given using a two-dimensional theory of elasticity in the case where two dissimilar plates are joined. Next, in the case of plates with the same material, effects of Young's modulus of plates to that of an adhesive and the thickness of the adhesive on the stress distribution are made clear by numerical computations. For verification, experiments are performed and an analytical result is in a fairly good agreement with an experimental one.     

Enzymatic synthesis of carbohydrate esters of fatty acid (I) esterification of sucrose,glucose, fructose and sorbitol

The authors attempted to synthesize carbohydrate esters of fatty acids enzymatically in order to overcome the problems associated with the chemical processes for the synthesis of commercial sucrose esters. The enzymes used were lipases from microorganisms belonging toRhyzopus, Enterbacterium, Aspergillus, Pseudomonas, Chromobacterium, Candida, Mucor andPenicillium. Fatty acids (stearic, oleic and linoleic) and carbohydrates (sucrose, glucose, fructose and sorbitol) used for the reaction were obtained from commercial sources. The enzyme reaction was performed by mixing the enzyme and the substrates in the buffer solution and incubating at 40 C; after freeze-drying the mixture, the products were extracted and subjected to thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). It was observed by TLC and HPLC that carbohydrate esters of fatty acid were produced by the enzyme reaction, and their structures were confirmed by infra red (IR) and nuclear magnetic resonance (NMR) spectrometries. The lipase fromCandida cylindracea was the most enzyme active on the synthesis of carbohydrate esters. The optimum conditions for its activity were as follows: molar ratio of carbohydrate to fatty acid: 0.05mol/l : 0.2mol/l; amount of lipase: 4g/l; pH of the reaction mixture: 5.4 in phosphate buffer; reaction period: 72 hr.