A FAST METHOD OF RADIATIVE HEAT TRANSFER ANALYSIS BETWEEN ARBITRARY THREE-DIMENSIONAL BODIES COMPOSED OF SPECULAR AND DIFFUSE SURFACES

The radiation element method by ray emission model (REM²) has been improved by using the law of reciprocity for the specular view factor and the incomplete Cholesky conjugate gradient (ICCG) method to reduce computational time. This improved method was applied to analyze the radiative heat transfer between arbitrary three-dimensional bodies composed of specular and diffuse surfaces. The accuracy of the improved method was evaluated by comparing analytical solutions. And the method was used to calculate radiative heat transfer between machine elements and heater panels. CPU time to calculate the radiative exchange for a model composed of 3193 elements was reduced to 1/430 of that by the previous numerical method using a decomposition method.     

Characterization of alternative plasticizers in poly(vinyl chloride) sheets for blood containers

This study aimed to optimize the ratio of dioctyl 4‐cyclohexene‐1,2‐dicarboxylate (DOTH) and di‐isononyl‐cyclohexane‐1,2‐dicarboxylate (DINCH^®) for use as plasticizers in poly(vinyl chloride) (PVC) sheets. We also evaluated the biological safety of DOTH for its potential to be part of a safe PVC‐based blood container. The suppression of hemolysis in mannitol‐adenine‐phosphate / red cell concentrates (MAP/RCC) with DOTH/(DINCH^®‐PVC) sheets and the elution of plasticizers from the sheets increased with higher DOTH compositions. The properties of the PVC sheet containing DOTH and DINCH^® in the ratio of 25:33 parts against PVC 100 parts as a weight were almost identical to the PVC sheet made of di(2‐ethylhexyl) phthalate. From a subchronic toxicity test, DOTH did not show any adverse effects on all organs, including the testes, epididymis, liver, and kidneys. The no‐observed‐adverse‐effect level was 300 mg/kg body weight/day in a rat. These results suggest that DOTH/DINCH^® (25:33) is a promising candidate for the replacement of di(2‐ethylhexyl) phthalate in blood containers. J. VINYL ADDIT. TECHNOL., 22:520–528, 2016. © 2015 Society of Plastics Engineers     

Excess Solute Carbon and Retained Tetragonality in Tempered Fe-0.6C-1Mn Martensite and the Effect of Silicon Addition

The tetragonality and carbon distribution in tempered Fe-0.6C-1Mn martensite were investigated by X-ray diffraction and atom probe tomography to elucidate strain relaxation in the tetragonal lattice during tempering and its relationship with the solubility of excess carbon in martensite. Even though tetragonality (c/a) decreased with an increase in the tempering temperature, it persisted at low levels up to 400 °C. Si addition suppressed the decrease in tetragonality at 400 °C by inhibiting recovery in the dislocated matrix. Such persistence implies that dislocation migration is crucial for the complete release of tetragonal lattice strain at such a temperature, in addition to the decrease in the amount of solute carbon in martensite. A low level of tetragonality was observed for martensite containing carbon in the solid solution below the critical value of ~ 0.2 mass pct, at which a bcc structure was predicted. The amount of solute carbon after tempering was linearly correlated with tetragonality in the solute carbon content range of 0.07 to 0.6 mass pct, and the correlation coefficient was similar to those for as-quenched auto-tempered martensite and bainitic ferrite; these results indicate that the amount of excess carbon is simply determined by the amount of tetragonal lattice distortions remaining after carbide precipitation and recovery.

     

Novel functional polymers: Poly(dimethylsiloxane)–polyamide multiblock copolymer. III. Synthesis and surface properties of disiloxane–aromatic polyamide multiblock copolymer

Disiloxane–aromatic polyamide(aramid) multiblock copolymers(2SiPASs) were synthesized using 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane(BATS) as an analog of aramidsilicone resin consisting of aromatic polyamide and poly(dimethylsiloxane) (PDMS). 2SiPASs afford a transparent and toughened plastic film. The surface properties of 2SiPAS were investigated by X-ray photoelectron spectroscopy (xps) and static contact angle measurement. The results of surface analysis suggested that BATS content of the 2SiPAS surface increased with increasing BATS content in bulk. The interaction between the platelets and the 2SiPAS surface was found to be very weak when the BATS content reached 26 wt % in bulk. © 1996 John Wiley & Sons, Inc.     

High-melt-strength polypropylene with electron beam irradiation in the presence of polyfunctional monomers

High-melt-strength polypropylene (PP) was achieved with irradiation by an electron beam generated from an accelerator in the presence of polyfunctional monomers (PFM). Among 16 PFMs, the relatively shorter molecular chain bifunctional monomers such as 1,4-butanediol diacrylate (BDDA) and 1,6-hexanediol diacrylate (HDDA) were the most effective for enhancing the melt strength of PP. The concentration and dose of the HDDA to obtain the high melt strength PP in irradiation under nitrogen gas atmosphere were 1.5 mmol/100 g PP and 1 kGy, respectively. DSC measurement and dynamic mechanical analysis showed that the thermal behavior of the high-melt-strength PP was different from that of the original PP. Crystallinity and crystallization temperature during cooling after heating were lower and higher in high melt strength PP than original PP, respectively. Elongational viscosity at 180°C of the high-melt-strength PP showed a remarkable increase at a certain elongational time with constant strain rate, demonstrating the typical property of high-melt-strength samples. This implies that a few higher molecular chains of PP, formed by intermolecular combination of its chain by HDDA in irradiation, give higher melt strength to induce entanglement of molecular chains. © 1996 John Wiley & Sons, Inc.     

Effect of poly(vinyl acetate/vinyl alcohol) copolymer with a thiol end group as a steric stabilizer on dispersion polymerization of styrene

In dispersion polymerization of styrene in ethanol, effects of a reactive steric stabilizer, poly(vinyl acetate/vinyl alcohol) copolymer with a thiol end group (P(VAc/VA)-SH), were investigated. In the absence of the thiol end group, the dispersion coagulated at the middle stage of the polymerization, while in the presence of the thiol end group, the polymerization proceeded successfully to result in close to monodisperse particles. The reactive thiol group acts as a site of formation of the block copolymer, that is, polystyrene-b-P(VAc/VA), which is utilized as an effective dispersant. From the measurement on molecular weights during the course of polymerization, two polymerization loci were realized. Addition of butyl methacrylate to styrene affected markedly not only rate of polymerization but also particle size. © 1996 John Wiley & Sons, Inc.     

Characteristics of a-Si solar cells prepared by the super chamber at a high substrate temperature

A new approach to high-performance a-Si solar cells was studied. a-Si films prepared at a high substrate temperature (> 250°C) have a higher absorption coefficient and a low Si H₂ bond density. the effect of deposition temperature on the open-circuit voltage (V_oc) has been investigated systematically for glass/SnO2 Ipin/metal and glass/metal/nip/indium tin oxide (ITO) structure a-Si solar cells. The V_oc is found to depend strongly on the thermal history of the p/i interface. A short-circuit current of 19.5 mA/cm⁻⁻² was achieved for an a-Si solar cell using an a-Si i-layer with a thickness of 4000 Å, which was prepared at a substrate temperature of 270°C.     

Color and Vanadium Valency in V-Doped ZrO2

The distribution and chemical states of vanadium in V-doped ZrO₂ were studied to clarify the origin of the color of vanadium-zirconium yellow pigment in comparison with vanadium-tin yellow pigment. ESCA data and measurements of lattice constants of V-doped ZrO₂ revealed that vanadium was dissolved mainly as V⁴⁺ substituting for Zr in ZrO₂ lattice, and its solubility limit was 0.5 wt% as V₂O₅. It was found that the yellow color of vanadium-zirconium yellow was produced predominantly by the dissolved vanadium and that the contribution of vanadium oxide on ZrO₂ grains to the yellow color was about 1/30 of that of the dissolved vanadium when compared on the basis of equimolar quantity of vanadium. Most of the undissolved vanadium oxide was in an amorphous or a poorly crystallized state.     

Synthesis of stable and soluble one-handed helical poly(substituted acetylene)s without chiral pendant groups via polymer reaction in membrane state

A soluble and stable one-handed helical conjugated polymer without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer having two hydroxyl groups followed by desubstitution of the chiral groups in a solid membrane state. The reason for the success was the polymer reaction was carried out in the membrane state. This is an alternative method to obtain such a unique chiral polymer which was obtained only by the helix-sense-selective polymerization (HSSP) we reported before. In addition the efficiency of the chiral induction was higher than that of the HSSP. It is interesting that the “Membrane state” acted like as if a protecting group.