The lubrication mechanism in low speed plastic deformation with a synthetic lubricant — infiltration of lubricant into the boundary contact region

To investigate and evaluate the micro-pool mechanism in a mixed lubrication regime using polybutene lubricants, experiments were performed using 1 mm brass sheet, for various surface rough nesses of a work piece and die, lubricant viscosities and extrusion speeds. Systematic study showed that (1) the lower viscosity lubricant is easily squeezed out from the micro-pools into the flat are a through the troughs between the tool and work piece caused by plastic deformation of work piece, and (2) with decrease in lubricant viscosity and speed, or the larger the tool surface roughness becomes, the more lubricant infiltrates into the tool-work piece interface, which reduces the actual friction coefficient.     

Am1 MO Study of Benzene Nitro Derivatives

Molecular properties of benzene nitro derivatives were investigated by using semi-empirical MO calculations. As the results, the molecular structures and the rotational barrier of the nitro group calculated by AM1 showed a good agreement with the experimental values. The heats of formation in gaseous and condensed phases were obtained by considering isodesmic reactions. By this procedure, the heat of formation of hexanitrobenzene in solid phase was calculated to be +22.7 kcal/mol. The detonation parameters were also calculated by using four equations of state. The predicted detonation velocities showed a good agreement with the experimental values.     

A Multiple‐Labeling Strategy for Nonribosomal Peptide Synthetases Using Active‐Site‐Directed Proteomic Probes for Adenylation Domains

Genetic approaches have greatly contributed to our understanding of nonribosomal peptide biosynthetic machinery; however, proteomic investigations are limited. Here, we developed a highly sensitive detection strategy for multidomain nonribosomal peptide synthetases (NRPSs) by using a multiple‐labeling technique with active‐site‐directed probes for adenylation domains. When applied to gramicidin S‐producing and ‐nonproducing strains of Aneurinibacillus migulanus (DSM 5759 and DSM 2895, respectively), the multiple technique sensitively detected an active multidomain NRPS (GrsB) in lysates obtained from the organisms. This functional proteomics method revealed an unknown inactive precursor (or other inactive form) of GrsB in the nonproducing strain. This method provides a new option for the direct detection, functional analysis, and high‐resolution identification of low‐abundance active NRPS enzymes in native proteomic environments.     

A photocatalytic membrane reactor for gas-phase reactions using porous titanium oxide membranes

Photocatalytic membrane reactors using porous titanium oxide membranes having pore sizes of several nanometers were utilized for a gas-phase reaction of methanol. Air mixed with methanol (MeOH) vapor, the concentration of which was controlled in the range of 500–6000 ppm, was fed to the photocatalytic membrane reactor in the range of 50–500 cm³/min using several types of flow patterns. Photocatalysis with membrane permeation resulted in a large decomposition rate, compared to photocatalysis without membrane permeation. The characteristics of the reaction such as decomposition ratio of MeOH, the conversion of the decomposed MeOH to CO₂ and H₂O were found to be a function of the residence time in the reactor. The photocatalytic reaction was analyzed based on pseudo-first-order kinetics to ascertain its simplicity, and the fitted curves were found to be in a relatively good agreement with the experimental data. Apparent rate constants with and without membrane permeation were 2.5 and 1.5×10⁻⁶ m s⁻¹, respectively, indicating that the performance of the photocatalytic reaction system with membrane permeation was enhanced.     

Effects of conservation tillage,crop residue and cropping systems on changes in soil organic matter and maize–legume production: a case study in Teso District

The effects of conservation tillage, crop residue and cropping systems on the changes in soil organic matter (SOM) and overall maize–legume production were investigated in western Kenya. The experiment was a split-split plot design with three replicates with crop residue management as main plots, cropping systems as sub-plots and nutrient levels as sub-sub plots. Nitrogen was applied in each treatment at two rates (0 and 60 kg N ha⁻¹). Phosphorus was applied at 60 kg P/ha in all plots except two intercropped plots. Inorganic fertilizer (N and P) showed significant effects on yields with plots receiving 60 kg P ha⁻¹ + 60 kg N ha⁻¹ giving higher yields of 5.23 t ha⁻¹ compared to control plots whose yields were as low as 1.8 t ha⁻¹ during the third season. Crop residues had an additive effect on crop production, soil organic carbon and soil total nitrogen. Crop rotation gave higher yields hence an attractive option to farmers. Long-term studies are needed to show the effects of crop residue, cropping systems and nutrient input on sustainability of SOM and crop productivity.     

Computational fluid dynamics simulation and statistical procedure for estimating wide-area distributions of airborne sea salt considering local ground conditions

Steel corrosion under atmospheric conditions is a critical issue in the maintenance of structures such as electric transmission towers and bridges during their long-term operation, which are generally located at many places over a wide area. Since a major factor causing corrosion is airborne salt particles coming from the sea, wide-area distributions of the long-term cumulative amount of sea salt deposited on surfaces are needed. Moreover, since the amount of airborne sea salt varies locally with the topography, it is also important to consider the effects of topography. In this paper, a method combining a computational fluid dynamics model and a statistical procedure is proposed to efficiently estimate wide-area distributions of the cumulative amount of airborne sea salt by considering the local topography. The predicted amount of airborne sea salt decreases with increasing distance from the coast and varies with the topography and the offshore wind. A comparison between predicted and observed amounts revealed that: (1) this method appropriately estimates topographical effects on sea-salt transport and enables the estimation of deposited sea salt on structure surfaces, and (2) consideration of the trapping efficiency of sea-salt particles on structure surfaces improves the prediction accuracy.     

Short-term irradiation behavior of minor actinide doped uranium plutonium mixed oxide fuels irradiated in an experimental fast reactor

A fuel irradiation program is being conducted using the experimental fast reactor ‘Joyo’. Two short-term irradiation tests in the program were completed in 2006 using a uranium and plutonium mixed oxide fuel which contains minor actinides (MA-MOX fuel). The objective of the tests is the investigation of early thermal behavior of MA-MOX fuel such as fuel restructuring and redistribution of minor actinides. Three fuel pins which contained MA-MOX: 2% neptunium and 2% americium doped uranium plutonium mixed oxide (Am,Pu,Np,U)O_2−x fuel were supplied for testing. The first test was conducted with high-linear heating rate of approximately 430 W cm⁻¹ for only 10 min. After the first test, one fuel pin was removed for examinations. Then the second test was conducted with the remaining two pins at nearly the same linear power for 24 h. In these tests, two oxygen-to-metal molar ratios were used for fuel pellets as a test parameter. Non-destructive and destructive post-irradiation examinations results are discussed with early on the behavior of the fuel during irradiation.