Water-soluble metalworking fluid additives derived from the derivatives of 3-mercaptopropionic acid

A number of derivatives of thiocarboxylic acid were prepared from the reaction of 3-mercaptopropionic acid and alkyl halides, and screened for anti-rust properties in water-soluble metalworking fluids. Aqueous metalworking fluids containing octylthiopropionic acid or hexylthioacetic acid showed excellent anti-rust properties for water-soluble metalworking fluids.     

Rate constant for CO insertion in the hydroformylation of ethene on Rh/SiO2 as determined by pulse surface reaction rate analysis

A new method of pulse surface reaction rate analysis (PSRA) was proposed for determining the rate constant of the step of CO insertion in ethene hydroformylation. On pulsing ethene onto Rh/SiO₂ via the continuous flow of a mixture of CO and H₂, propanal was found to be produced gradually. It is revealed here that rate analysis of the dynamic behavior of produced propanal allows the determination of the rate constant for CO insertion. The effect of metal carbonate and oxides, added to the catalyst, on CO insertion was discussed in terms of the rate constant determined.     

Electrochemical behavior of poly(3-hexylthiophene). Controlling factors of electric current in electrochemical oxidation of poly(3-hexylthiophene)s in a solution

Electrochemical response of regio-random and regio-controlled poly(3-hexylthiophene), P3HexTh, was investigated by cyclic voltammetry. P3HexTh underwent electrochemical oxidation at about 0.4 V vs. Ag⁺/Ag in a THF solution, and the peak anode electric current, i_pa, was proportional to the sweeping rate v; i_pa=const×v^1/2. These data indicated that diffusion of the P3HexTh molecule in the solution was important to determine i_pa. Application of a Matsuda's equation with assumptions gave a diffusion coefficient, D, of about 1×10⁻⁷ cm² s⁻¹ at molecular weight of about 5000, and the D value steeply decreased with increase in the molecular weight.     

Fabrication and characterization of tetragonal yttria-stabilized zirconia single-crystalline thin film

Tetragonal yttria-stabilized zirconia thin film was successfully fabricated by a pulsed laser deposition method. The thin film grew heteroepitaxially with the orientation relationship of ZrO₂‖Al₂O₃. Energy dispersive X-ray spectroscopy mapping revealed that Y³⁺ ions were distributed homogeneously without local segregations. X-ray and electron-diffraction analysis confirmed a single crystalline structural feature of the film. On the other hand, high-resolution scanning transmission electron microscopy observations show that this film contains small-angle tilt grain boundaries, which is composed of the periodic array of dislocations with the Burgers vector .     

A Stress Analysis of Butt Adhesive Joints Under Torsional Loads

The stress distribution and the displacement are examined when a butt adhesive joint, in which two dissimilar tubular shafts are joined, is subjected to a torsional load. In the analyses, general representations of the stresses and the displacements are given as a torsion problem when two dissimilar tubular shafts are band-adhesively bonded. Next, in the case of shafts with the same material, effects of the ratio of the shear modulus of an adhesive to that of shafts, the thickness of the adhesive and the bonded position of band-adhesive on the stress distribution are made clear by numerical computations. Moreover, when solid shafts are joined, these effects are made clear by the similar analyses and numerical computations.     

Stress Analysis of T-type Butt Adhesive Joint Subjected to External Bending Moments

Stress distributions and displacements at the interface between an adhesive and an adherend are examined when a T-type butt adhesive joint, in which two thin plates are joined, is subjected to an external bending moment. In the analyses, general representations of the stresses and the displacements are given using a two-dimensional theory of elasticity in the case where two dissimilar plates are joined. Next, in the case of plates with the same material, effects of Young's modulus of plates to that of an adhesive and the thickness of the adhesive on the stress distribution are made clear by numerical computations. For verification, experiments are performed and an analytical result is in a fairly good agreement with an experimental one.     

Fabrication of gold nanoparticle pattern using imprinted hydrogen silsesquioxane pattern for surface-enhanced Raman scattering

This is the first report of surface-enhanced Raman scattering (SERS) substrate fabrication using a combination of imprinted hydrogen silsesquioxane (HSQ: HSiO_3/2) patterns and self-assembly of gold nanoparticles (AuNPs). To assemble the AuNPs inside the imprinted HSQ pattern, it is important to understand the interactions between AuNPs and AuNPs, and those between AuNPs and HSQ. The authors investigated the effects HSQ surface charges on the self-assembly of AuNPs. It was found that the negatively charged AuNPs were successfully assembled according to the geometry of the negatively charged HSQ pattern. In addition, it was shown that the SERS substrate fabricated from an HSQ consisting of an inorganic polymer was suitable for organic chemical analysis, by comparing it with a substrate fabricated using an organic polymer.     

Carbonization of coals to produce anisotropic cokes: 3. Evaluation of low-rank bituminous and subbituminous coals by single and co-carbonizations with pitch

Single carbonizations and co-carbonizations of 17 low-rank bituminous and subbituminous coals have been studied to evaluate their suitability as sources of blast furnace coke in terms of pore-wall profile and anisotropic development within the cokes. Co-carbonizations suggest the possible use of low-rank coals which from single carbonizations would not have been considered suitable. To evaluate semi-quantitatively the coke quality, two structural characteristics of the cokes produced by single and co-carbonizations are graded on a scale of 1 to 5. Overall assessments for each coal are plotted against the atomic H/C and 0/C ratios of the original coals. Although there are a few exceptions, coals with similar assessments are located in the same region of the plot, indicating that, to a first approximation, the H/C and 0/C ratios are suitable indicators of the single and co-carbonization properties of a coal. The presence of cations in the coal appears to be an additional factor influencing the carbonization properties and may explain the exceptional behaviour of some coals. Removal of these cations by pretreatment of the coals improves the carbonization properties.     

Directed evolution of Pseudomonas aeruginosa lipase for improved amide-hydrolyzing activity

A lipase from Pseudomonas aeruginosa was subjected to directed molecular evolution for increased amide-hydrolyzing (amidase) activity. A single round of random mutagenesis followed by screening for hydrolytic activity for oleoyl 2-naphthylamide as compared with that for oleoyl 2-naphthyl ester identified five mutants with 1.7-2.0-fold increased relative amidase activities. Three mutational sites (F207S, A213D and F265L) were found to affect the amidase/esterase activity ratios. The combination of these mutations further improved the amidase activity. Active-site titration using a fluorescent phosphonic acid ester allowed the molecular activities for the amide and the ester to be determined for each mutant without purification of the lipase. A double mutant F207S/A213D gave the highest molecular activity of 1.1 min(-1) for the amide, corresponding to a 2-fold increase compared with that of the wild-type lipase. A structural model of the lipase indicated that the mutations occurred at the sites near the surface and remote from the catalytic triad, but close to the calcium binding site. This study is a first step towards understanding why lipases do not hydrolyze amides despite the similarities to serine proteases in the active site structure and the reaction mechanism and towards the preparation of a general acyl transfer catalyst for the biotransformation of amides.