Analysis of saturation currents and barrier height of Ta2O5 doped based on Ba0,5S0,5TiO3 photodiode

Ba_0,5Sr_0,5TiO₃ (BST) thin films have been prepared on Si (100) p-type substrates using a chemical solution deposition (CSD) method and doped with 0%, 2.5%, 5%, 7.5%, 10% tantalum pentaoxide (Ta₂O₅). Chemical Solution Deposition Method (CSD) used the spin coating techniques with a rotational speed of 3000?rpm for 30?seconds. BST thin films annealed at a temperature 850?°C. Various electrical parameters such as saturation current, series resistance and barrier height have been calculated from the analysis of experimental I–V results and discussed in detail. The series resistance was found from the experiment of 42.8 MΩ, 7.9 MΩ, 7.2 MΩ, 2.03 MΩ, 1.2 MΩ for variation doping content. The saturation current of 22.3 μA, 2.7 μA, 9.7 μA, 4.82 μA, 4.50 μA was obtained in BST thin film with variation doping content. Then, the barrier height of 0.56?eV, 0.62?eV, 0.58?eV, 0.54?eV, 0.60?eV was obtained in BST thin film with variation doping content. The optical characterization and analysis microstructure such as XRD, EDX were discussed in detail.     

Wettability and bonding quality of exterior coatings on jabon and sengon wood surfaces

Wettability and bonding quality of exterior coatings on fast-growing wood surfaces were studied. Samples of air-dried flat-grained (tangential surface) and edge-grained (radial surface) pattern of jabon (Anthocephalus cadamba) and sengon (Paraserianthes falcataria) woods were used. Before application of exterior coatings, the surfaces of the lumber samples were sanded. To provide wood surfaces with various degrees of roughness, abrasive papers of 120, 240, and 360 grits were used for the surface preparation. The wettability of two exterior coatings (water-based acrylic and oil-based alkyd varnishes) on the sanded wood surfaces was measured using a sessile drop contact angle method. The Shi and Gardner (S/G) model was used to evaluate and compare the wettability of the surface coatings on the wood. The sanded wood samples were coated with the two coatings (two layers each). Bonding quality of the coating layers was measured using a crosscut tape test method. Experimental results show that constant contact angle change rate (K value) of the S/G model decreased as the grit number of abrasive paper increased. This indicates that the wettability decreased as the roughness of the surface decreased (surface becomes smoother). There was no evidence of differences in wettability between tangential and radial wood surfaces. The oil-based alkyd coating generated better wettability compared to the water-based acrylic. The crosscut tests showed that the bonding quality of the coating films on both jabon and sengon wood decreased as the surface became smoother. The sengon wood compared to jabon wood provided better coating wettability and bonding quality. Wettability in terms of the K values was a good indication for determining the bonding quality of the two varnish layers.     

Feasibility study of utilization of commercially available polyurethane resins to develop non-biocidal wood preservation treatments

Evaluation of commercially available polyurethane resins used up to now for coating applications to develop non-biocidal wood preservation treatments has been conducted. A simple method of vacuum impregnation of these resins into beech wood (Fagus sylvatica L.) and pine wood (Pinus sylvestris L.) samples followed by varied curing processes at ambient temperature, 103, and 200 °C has been performed. Based on the analysis of weight percent gain before and after leaching, treatment resistance to leaching, anti-swelling efficiency, wettability and decay durability measured for treated and untreated blocks after leaching with the white-rot fungus Coriolus versicolor for both wood species and the brown-rot fungi Poria placenta and Gloeophyllum trabeum for pine wood, it can be concluded that such treatment can be considered as potential valuable non-biocidal treatments.     

Distribution of Defensive Metabolites in Nudibranch Molluscs

Many plants and animals store toxic or unpalatable compounds in tissues that are easily encountered by predators during attack. Defensive compounds can be produced de novo, or obtained from dietary sources and stored directly without selection or modification, or can be selectively sequestered or biotransformed. Storage strategies should be optimized to produce effective defence mechanisms but also prevent autotoxicity of the host. Nudibranch molluscs utilize a diverse range of chemical defences, and we investigated the accumulation and distribution of defensive secondary metabolites in body tissues of 19 species of Chromodorididae nudibranchs. We report different patterns of distribution across tissues, where: 1) the mantle had more or different (but structurally related) compounds than the viscera; 2) all compounds in the mantle were also in the viscera; and 3) the mantle had fewer compounds than the viscera. We found no further examples of species that selectively store a single compound, previously reported in Chromodoris species. Consistent with other studies, we found high concentrations of metabolites in mantle rim tissues compared to the viscera. Using bioassays, compounds in the mantle were more toxic than compounds found in the viscera for Glossodoris vespa Rudman, 1990 and Ceratosoma brevicaudatum Abraham, 1876. In G. vespa, compounds in the mantle were also more unpalatable to palaemonid shrimp than compounds found in the viscera. This indicates that these species may modify compounds to increase bioactivity for defensive purposes and/or selectively store more toxic compounds. We highlight clear differences in the storage of sequestered chemical defences, which may have important implications for species to employ effective defences against a range of predators.     

Biodesulfurization of alkylated forms of dibenzothiophene and benzothiophene by Sphingomonas subarctica T7b

Sphingomonas subarctica T7b was isolated from soil in Toyotomi, Hokkaido, Japan as an organism capable of desulfurizing aromatic hydrocarbons in light gas oil (LGO) through enrichment culture. S. subarctica T7b could grow on mineral salt sulfur-free (MSSF) medium with the n-tetradecane oil phase containing dibenzothiophene (DBT), alkyl dibenzothiophenes (alkyl DBTs) or alkyl benzothiophenes (alkyl BTs) as the sole sulfur source and desulfurize these compounds, but could not utilize the tetradecane as a carbon source. This is the first report of a gram-negative bacterium which can desulfurize 4,6-dibutyl DBT and 4,6-dipentyl DBT. The desulfurized product of DBT produced by this strain was 2-hydroxybiphenyl, as in the case of other DBT-desulfurizing bacteria. S. subarctica T7b could desulfurize LGO and the sulfur content was decreased to 41% within 36 h.     

Diploid porcine parthenotes produced by inhibition of first polar body extrusion during in vitro maturation of follicular oocytes

We investigated nuclear progression and in vitro embryonic development after parthenogenetic activation of porcine oocytes exposed to cytochalasin B (CB) during in vitro maturation (IVM). Nuclear progression was similar in control oocytes and oocytes matured in the presence of 1 microg/ml CB (IVM-CB group) by 37 h IVM; at this time the proportion of oocytes that had reached or passed through the anaphase-I stage did not differ significantly between the IVM-CB and the control groups (61.3 and 69.9% respectively; P < 0.05). After IVM for 37 h, no polar body extrusion was observed in the IVM-CB group. In these oocytes, the two lumps of homologous chromosomes remained in the ooplasm after their segregation and turned into two irregular sets of condensed chromosomes. By 41 h IVM, the double sets of chromosomes had reunited in 89.5% IVM-CB oocytes and formed a single large metaphase plate, whereas 68.8% of the control oocytes had reached the metaphase-II stage by this time. When IVM-CB oocytes cultured for 46 h were stimulated with an electrical pulse and subsequently cultured for 8 h without CB, 39.0% of them extruded a polar body and 82.9% of them had a female pronucleus. Chromosome analysis revealed that the majority of oocytes that extruded a polar body were diploid in both the control and the IVM-CB groups. However, the incidence of polyploidy in the IVM-CB group was higher than that in the control group (P < 0.05). In vitro development of diploid parthenotes in the control and the IVM-CB groups was similar in terms of blastocyst formation rates (45.8 and 42.8% respectively), number of blastomeres (39.9 and 44.4 respectively), the percentage of dead cells (4.3 and 2.9% respectively), and the frequency of apoptotic cells (7.3 and 6.3% respectively). Tetraploid embryos had a lower blastocyst formation rate (25.5%) and number of cells (26.2); however, the proportion of apoptotic nuclei (7.0%) was similar to that in diploid parthenotes. These results suggest that the proportion of homozygous and heterozygous genes does not affect in vitro embryo development to the blastocyst stage.     

Performance of laser-treated AISI-M2 cutting tools for peeling beech

For many wood machining processes, the interest of tool steels remains very important because of their good tool edge accuracy and easy grinding. The main problem is their low resistance to wearing and corrosion. In order to increase their performance, a laser melting and cladding applied on the tool edges is presented in this paper. Firstly, annealed AISI-M2 bar was melted, and M2 powder was cladded onto the AISI L2 substrate by a laser beam. The microstructure and microhardness of the M2 melted and M2 clad were characterised. Secondly, their wear resistance was tested for peeling beech wood. The experimental results show that metallurgical structure obtained by conventional heat treatment for the M2 was ferritic polycrystalline with coarse primary carbides, and the microstructure of the M2 melted and M2 clad, in which whole primary carbides were completely dissolved during laser melting and cladding, was observed to reveal fine iron dendritic structure. The M2 melted and M2 clad, which were almost the same in microhardness, had larger microhardness compared to the M2 conventional. The wear resistance and wear pattern of the M2 melted and M2 clad cutting tools in peeling beech were better than those of the M2 conventional cutting tool. Also the M2 melted and M2 clad cutting tools produced better surface quality of veneer and retained better cutting edges roughness compared to the M2 conventional.     

Mie scattering by a spherical particle in an absorbing medium

We show that the large-size parameter limit of the scattering efficiency of a spherical particle of relative refractive index m(r) embedded in an absorbing medium is equal to [m(r) - 1[2/]m(r) + 1]2 and not to zero as has been claimed in a recent article [J. Appl. Opt. 40, 1354-1361 (2001)].     

Clearance wear and normal force of TiN-coated P30 in cutting hardboards and wood-chip cementboards

This paper presents the clearance wear and normal force characteristics of TiN coated P30 when cutting hardboards and wood-chip cement boards. Hardboards and wood-chip cement boards of low density (about 0.8 g/cm³) and high density (about 1.2 g/cm³) were cut by using TiN coated P30. Cutting tests were performed at a cutting speed of 1000 m/min and a feed rate of 0.1 mm/rev to investigate the effect of the work materials on the clearance wear and normal force characteristics of the TiN coated P30. The experimental results showed that the TiN coated P30, compared to uncoated P30, is more advantageous in reducing the progression of wear on the clearance face, and in retaining lower normal force in cutting both hardboards and wood-chip cement boards. The amount of clearance wear suffered by the TiN coated P30 for the wood-chip cement board was larger compared to that for the hardboard. Though the TiN coated P30 suffers higher wear for the low density wood-chip cement board than the low density hardboard, its normal force, however, is always lower for the low density wood-chip cement board. It was observed that the clearance wear of the TiN coated P30 occurs due to delamination of TiN film and the wear of the substrate occurs after the coating film was disappeared from the substrate.     

Dynamical features of GPS PWV variation associated with lightning activity

Water vapour is one component that causes spatial and temporal fluctuations in the lower atmosphere, which, in turn, introduce time delays into the global positioning system (GPS) signal. These delays can be exploited to estimate the precipitable water vapour (PWV), which is beneficial for meteorological applications. Because the vertical transfer of warm air to the troposphere triggers instability and atmospheric charges, lightning phenomena can fundamentally affect the GPS signals through changes in water vapour. From this hypothesis, GPS-derived PWV data have been proposed as a tool for monitoring lightning activity. In this paper, the variation of PWV in days with lightning at four selected stations in Peninsular Malaysia during the past two inter-monsoon events in May and November 2009 was observed. To verify the response, a peak alignment method was proposed with regard to the lightning with more than 100 discharge events and lightning days from 07:00 to 20:00 LT. A total of 66 lightning series were assessed, and PWV was observed to increase by approximately 2.46 mm and decrease by 4.16 mm before and after the peak point, respectively, when compared to fair-weather conditions. Approximately 62% of the lightning start times were concentrated within a period of less than 1 h before or after the PWV reached a maximum peak, 24% were observed between 1–2 h, and 14% started after 2 h. This trend implies that the use of GPS PWV data was more consistent and robust for the detection of lightning activity compared to the use of surface temperature and relative humidity data.