Effect of electron beam radiation on the performance of biodegradable Bionolle-jute composite

To study the radiation effect on the physical, thermal, mechanical and degradable properties of biodegradable polymer Bionolle (chemosynthetic polyester poly(1,4-butylene succinate)), Bionolle films prepared by compression molding process and were irradiated with electron beam (EB) radiation of different doses. Gel content was found to increase with increase of radiation dose. Tensile strength of Bionolle was enhanced when Bionolle film was exposed under 20 kGy radiation. The loss of tensile strength of both unirradiated and irradiated Bionolle is 70% and 8% due to thermal aging at 70°C for 30 days. Both irradiated and unirradiated films of Bionolle were subjected to different degradation test in compost (soil burial), enzyme and storage degradation both in outdoor and indoors conditions. The loss of weight due to soil (compost) degradation test decreased with increase of radiation dose. The loss of weights of irradiated samples were found to be very less within the first three months of compost degradation. After 120 days, tensile strength of the Bionolle films irradiated at 20 kGy and 100 kGy were 68 MPa and 40 MPa, respectively, compared to the value (30 MPa) of the unirradiated Bionolle samples. Loss of tensile strength of irradiated Bionolle due to storage degradation like in roof, ground and indoors was minimum compared to unirradiated Bionolle. The weight loss due to enzymatic degradation was found to be decreased with increase of radiation dose. The tensile strength of jute reinforced Bionolle composites (23 wt.-% jute content) irradiated at 20 kGy was found to be higher (22%) than that of an unirradiated composite.     

Crosslinking of cis-1,4-polyisoprene rubber by electron beam irradiation

Various unsaturated polyfunctional monomers were kneaded into cis-1,4-polyisoprene containing fillers under 80°C and then irradiated using an electron beam accelerator to prepare vulcanized rubber with good quality. Results showed that 2G (diethyleneglycol dimethacrylate) is the best sensitizer. The optimal tensile strength of vulcanized IR was obtained by using 14 phr 2G and irradiated to 180 kGy. Compared with the sulfur vulcanizate, greater values of tensile strength, elongation at break, and 100% stress were found with the radiation-cured IR. Their Young's modulus and tan σ were similar. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 113–116, 1997     

Alcohol oxidase hybrid oligomers formed in vivo and in vitro

Cell‐free extract prepared from methanol‐grown cells of the methylotrophic yeast Pichia methanolica showed nine multiple alcohol oxidase (AOD) bands on active staining in native polyacrylamide gel electrophoresis. Their molecular basis was investigated and two AOD‐encoding genes, MOD1 and MOD2, were cloned from P. methanolica genome. When the two genes were expressed in a heterologous host, an alcohol oxidase‐depleted strain of Candida boidinii(aod1Δ strain), both MOD1 and MOD2 partially complemented growth defect of the host strain on methanol. While expression of either MOD1 or MOD2 in C. boidinii aod1Δ strain gave a single AOD band corresponding to the band with the largest and smallest mobility among the nine AOD bands, respectively, co‐expression of MOD1 and MOD2 resulted in multiple band formation. Mixed oligomerization of Mod1p and Mod2p in vitro also gave nine multiple bands. From these results, we concluded that the nine multiple forms of AOD observed on native–PAGE represent two homo‐octamers and seven hetero‐octamers of Mod1p and Mod2p. Using this zymogram analysis, we also found that Mod1p was preferably produced at low methanol concentrations in the media, while Mod2p was produced at higher methanol concentrations. This shows distinct regulatory features of the two AOD‐encoding genes in this methylotrophic yeast. Copyright © 1999 John Wiley & Sons, Ltd.     

Hydrogel coating of RVNRL film by electron‐beam irradiation

The tackiness properties of radiation‐vulcanized natural rubber latex (RVNRL) film surfaces coated by various monomers were investigated in order to define the suitable hydrogels which reduce the tackiness of the film. In this context, different types of monomers, namely, N‐vinyl‐2‐pyrrolidone (NVP), N,N‐dimethylaminoethylamide (DMAEA), acrylic acid (AAc), n‐butyl acrylate (n‐BA), and 2‐hydroxyethyl methacrylate (HEMA) as well as the monomer mixtures were tried with varying degrees of success. Coating the RVNRL film with 80% HEMA/20% n‐BA by irradiation at 80 kGy using a low‐energy electron beam gave a remarkable reduction in the surface tackiness of the RVNRL film. Several other attempts were made such as priming the RVNRL film with acid and aluminum sulfate prior to coating, mixing the aluminum sulfate into the monomer mixtures, and dipping the partially wet RVNRL film into the monomer to enhance the wettability of the monomers with the film. The photomicrographs taken illustrate that the decrease in tackiness with the coating is due to the increase of the surface roughness at an 80‐kGy irradiation dose. The studies also revealed that the reduction in the contact angle and the increase in water absorption of the RVNRL film after irradiation are due to the formation of the hydrogel layer. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1421–1428, 1999     

Heat transfer characteristics of fluid flow in an annulus with an inner rotating cylinder having a labyrinth structure

The convective heat transfer coefficient was experimentally investigated in an annulus with an inner rotating cylinder to estimate the thermal fatigue of the inner and outer cylinders on the rotating machine. The following three conclusions were obtained: (1) Within the range of the experimental conditions, the heat transfer coefficient did not depend on the axial flow rate; rather, it showed a larger dependence on the inner cylinder rotating speed. (2) The heat transfer coefficient at the top of the labyrinth was about three times as large as that at the bottom. (3) An empirical correlation equation considering the gap between the inner and outer cylinders is proposed, which predicts the heat transfer coefficient on the rotating machine within ±30 percent. © 1997 Scripta Technica. Inc. Heat Trans Jpn Res. 25 (2): 103–119, 1996     

Micro-mechanism of initiation of sliding

In order to understand the effects of contact shape and sliding direction on tangential coefficient a VTR (Video Tape Recorder) computer system has been developed to visualise the micro-slip distribution at the contact interface, during the process of micro displacement, before macro sliding. It is shown that micro-slip distribution is strongly affected by the shape of the contact area and the sliding direction, which gives a good explanation of the observed relationships between tangential coefficient (defined as tangential force divided by normal load) and tangential displacement. It is suggested, as a result, that the VTR-computer system developed in this study allows useful observation and understanding of the micro-mechanism of initiation of macro sliding.     

锥面包络环面蜗杆失配啮合传动的研究

提出了用不同产形面展成锥面包络环面蜗杆失配啮合传动的方法。用齿面接触分析法求解了失配啮合传动和齿面接触状态和运动精度。进行了相应的加工工艺试验和齿面啮合对检试验。理论计算和试验结果表明：该失配啮合传动可有效地降低包络环面蜗杆传动的啮合性能对制造误差的敏感性。     

Reaction of α-tocopherol in heated bulk phase in the presence of methyl linoleate (13S)-hydroperoxide or methyl linoleate

α-Tocopherol and methyl (9Z, 11E)-(S)-13-hydroperoxy-9, 11-octadecadienoate (13-MeLOOH) were allowed to stand at 100°C in bulk phase. The products were isolated and identified as methyl 13-hydroxyoctadecadienoate (1), stereoisomers of methyl 9,11,13-octadecatrienoate (2), methyl 13-oxo-9, 11-octadecadienoate (3), epoxy dimers of methyl linoleate with an ether bond (4), a mixture of methyl (E)-12, 13-epoxy-9-(α-tocopheroxy)-10-octadecenoates and methyl (E)-12, 13-epoxy-9-(α-tocopheroxy)-11-(α-tocopheroxy)-9-octadecenoates (5), a mixture of methyl 9-(α-tocopheroxy)-10,12-octadecadienoates and methyl 13-(α-tocopheroxy)-9, 11-octadecadienoates (6), α-tocopherol spirodiene dimer (7), and α-tocopherol trimer (8). α-Tocopherol and 13-MeLOOH were dissolved in methyl myristate, and the thermal decomposition rate and the distributions of reaction products formed from α-tocopherol and 13-MeLOOH were analyzed. α-Tocopherol disappeared during the first 20 min, and the main products of α-tocopherol were 5 and 6 with the accumulation of 1–4 which were the products of 13-MeLOOH. The results indicate that the alkyl and alkoxyl radicals from the thermal decomposition of 13-MeLOOH could be trapped by α-tocopherol to produce 5 and 6. The reaction products of α-tocopherol during the thermal oxidation of methyl linoleate were compounds 6 and 7. Since the radical flux during the autoxidation might be low, the excess α-tocopheroxyl radical reacted with each other to form 7.