Thermal response in thermal energy storage material around heat transfer tubes: effect of additives on heat transfer rates

The effects of carbon-fiber chips and carbon brushes as additives on the thermal conductivity enhancement of phase change materials (PCMs) using in latent heat thermal energy storage are investigated experimentally and numerically by considering the wall effect of the additives. The carbon-fiber chips are effective for improving the heat transfer rate in PCMs. However, the thermal resistance near the heat transfer surface is higher than that for the carbon brushes. As a result, the overall heat transfer rate for the fiber chips is lower than that for the carbon brushes. Consequently, the carbon brushes are superior to the fiber chips for the thermal conductivity enhancement under the present experimental conditions. The carbon brushes are moreover applied to the packed beds of particles to overcome their low thermal conductivity in chemical heat pump/storage. The carbon brushes essentially improve the heat transfer characteristics in the packed beds, though the thermal resistance is observed because the particles obstruct contact between the fibers and the heat transfer surfaces.     

Non-linear current–voltage characteristics related to native defects in SrTiO3 and ZnO bicrystals

SrTiO₃ and ZnO bicrystals with various types of boundaries were fabricated in order to examine their current–voltage characteristics across single grain boundaries. Their grain boundary structures were also investigated by high-resolution transmission electron microscopy. In Nb-doped SrTiO₃, electron transport behaviors depend on the type of boundaries. Random type boundaries exhibit highly non-linear current–voltage characteristics, while low angle boundaries show a slight non-linearity. On the contrary, undoped ZnO does not exhibit non-linear current–voltage characteristics in any type of boundaries including random ones. It is suggested that the differences observed in current–voltage properties between the two systems are mainly due to the difference in the accumulation behavior of acceptor-like native defects at grain boundaries. A clear non-linearity is obtained by means of Co-doping even for the highly coherent Σ1 boundary in a ZnO bicrystal. This is considered to result from the production of acceptor-like native defects by Co-doping.     

Micro-computerized tomographic observation of the spinning apparatus in Bombyx mori silkworms

Silkworms and spiders have evolved complex spinning apparatus thought to use highly controlled conditions to optimize protein folding and crystallization to provide a tough fiber. Accordingly, the structure and function of the natural spinning apparatus has been studied with great attention as an interesting piece of biological engineering with potential for mimicry in an industrial process. However it is still not well understood. Here we used Micro-Computerized Tomographic equipment (mCT) to visualize the three-dimensional structure of the spinning apparatus in Bombyx mori silkworms. Multidirectional tomograms obtained by X-ray radioscopy provided valuable information on the detailed arrangement of each muscle of the silk press. It is suggested that the duct in the silk press part plays a part as an extrusion die whose cross-sectional area can be controlled by muscles to optimize applied stresses in the partially gelled silk within its lumen.     

Accelerator Analysis of Tributyltin Adsorbed onto the Surface of a Tributyltin Resistant Marine Pseudoalteromonas sp. Cell

Tributyltin (TBT) released into seawater from ship hulls is a stable marine pollutant and obviously remains in marine environments. We isolated a TBT resistant marine Pseudoalteromonas sp. TBT1 from sediment of a ship’s ballast water. The isolate (10^{9.3 ± 0.2} colony-forming units mL⁻¹) adsorbed TBT in proportion to the concentrations of TBTCl externally added up to 3 mM, where the number of TBT adsorbed by a single cell was estimated to be 10^8.2. The value was reduced to about one-fifth when the lysozyme-treated cells were used. The surface of ethanol treated cells became rough, but the capacity of TBT adsorption was the same as that for native cells. These results indicate that the function of the cell surface, rather than that structure, plays an important role to the adsorption of TBT. The adsorption state of TBT seems to be multi-layer when the number of more than 10^6.8 TBT molecules is adsorbed by a single cell.     

A new non-random chromosomal translocation t(3;6)(q27;p21.3) associated with BCL6 rearrangement in two patients with non-Hodgkin's lymphoma

We describe two cases of non-Hodgkin's lymphoma associated with t(3;6)(q27;p21.3) and BCL6 rearrangement. The first case was in a 78-year old woman, whose performance status (PS) was 1, the serum lactate dehydrogenase (LDH) level was elevated, and the Ann Arbor stage was IIIA with no extra nodal lymphomatous site. The pathological diagnosis from a biopsy of the inguinal lymph node was 'malignant lymphoma (ML), follicular, small cleaved' according to the Working Formulation. Complete remission was achieved. Although she had relapse in 1992, remission was obtained again. The second case was in a 62-year old man, whose PS was 1, the serum LDH was normal, and Ann Arbor stage was IVA with the involvement of the small intestine. Histological diagnosis of the cervical lymph node was 'ML, diffuse, large cell'. Complete remission was obtained without relapse. The 3q27 translocations, found in 20-30% of non-Hodgkin's lymphoma, are unique in having multiple chromosomal translocation partners. Chromosome band 6p21.3 is one of these partner sites that may be the site of a novel gene. The two cases presented here show that this translocation is a non-random chromosomal change involving 3q27 and BCL6. Since t(3;6) was the sole karyotypic abnormality in one case, this translocation may play a role in lymphomagenesis.     

Effect of MgO Addition on the Bondability and Interfacial Reaction between Dielectric and Glass-Ceramics for the Fabrication of Multi-Component Ceramic Substrates

Bondability and interfacial reaction between dielectric and insulator layers have been examined to obtain a basic understanding of bonding mechanisms. Lead-containing complex perovskite was used as a dielectric material. Two kinds of glass-ceramics were used as insulator material; lead borosilicate glass containing Al_2O3 (insulator A) and the same containing Al₂O₃ and M_gO (insulator B). Dielectric and insulator layers did not bond when insulator A was used. When insulator B was used, however, strong bonding was achieved between the two layers by firing the powder compacts at temperatures between 800° and 1000°C. Addition of M_gO to lead borosilicate glass increased the thermal expansion coefficient to that of the dielectric and enhanced the formation of reaction layers, resulting in good bonding. Two reaction layers were identified. The main reaction products were enstatite and bredigite for one layer contacting the dielectric, and enstatite and a compound with the same diffraction pattern as that of faujasite for the other layers contacting insulator B.     

Polymerization of methyl methacrylate by tri-n-butylborane in the presence of amino acid esters

The polymerization of methyl methacrylate by tri-n-butylborane in the presence of amino acid esters was investigated. The binary systems of tri-n-butylborane and amino esters were found to be more effective for initiating the polymerization than tri-n-butylborane alone. Co-catalytic effects of amino acid esters were in the order: tyrosinate > glutamate > aspartate ? phenyl alaninate > serinate > glycinate. The rate of polymerization in a mixture of dimethylsulphoxide and toluene was proportional to the square root of the concentration of the initiator system, to the monomer concentration, and to the concentration of dimethylsulphoxide in the solvent. The overall energy of activation was estimated to be 4.6 kcal/mol for the tri-n-butylborane/methyl tyrosinate system. Copolymerization curves gave a typical free-radical character.     

The effect of the N-linked glycans on structural features and physicochemical functions of soybean β-conglycinin homotrimers

β-Conglycinin is a trimeric protein consisting of three subunits, α,α′,and β, which are N-glycosylated. The α and α′ subunits contain extension regions in addition to core regions common to all subunits. We purified homogeneous trimers consisting of only α, α′, or β from mutant soybean cultivars containing β-conglycinin lacking one or two subunits: α homotrimers from an α′-lacking mutant, α′ homotrimers from an α-lacking mutant, and β homotrimers from an α-and α′-lacking mutant. Structural features and physicochemical functions of the three homotrimers were examined and compared with those of recombinant homotrimers having no N-linked glycans. The native homotrimers have secondary structures very similar to those of the recombinant ones. In analogy with the recombinant homotrimers, the native ones exhibit different thermal stabilities from one another (β>α′>α), and the native α and α′ homotrimers exhibit better solubility, emulsifying ability, and heat-induced association than the native β homotrimer. Further, the N-linked glycans contribute to solubilities of the three subunits at low ionic strength (μ=0.08) and to the emulsifying ability of the native β homotrimer. N-Linked glycans also prevent heat-induced associations of the native α and α′ homotrimers but do not contribute to the secondary structure and the thermal stability of β-conglycinin.     

Development of a high‐resolution RGBW flexible display using a white organic light‐emitting diode with microcavity structure and that of a side‐roll touch panel

In this study, white organic electroluminescent devices with microcavity structures were developed. A flexible high‐resolution active‐matrix organic light‐emitting diode display with low power consumption using red, green, blue, and white sub‐pixels formed by a color‐filter method was fabricated. In addition, a side‐roll touch display was developed in combination with a capacitive flexible touch screen.