Free-form curves cutting using flexible circular saw

A flexible circular saw, which can be used in a novel machining process for high-speed carbon fiber-reinforced plastic (CFRP) plate cutting, was developed. In this process, the saw is deflected like a bowl-like shape. A cross-section of the saw body then forms a circular arc. A curved line can therefore be cut without interference by the bowl-like deflection. In addition, the radius of the cross-section of the saw body can be controlled by adjusting the deflection. This process therefore allows curves to be cut with a varied radius using a single saw. This process can carry out high-speed curved-line cutting with a feed rate of 3 m/min on a CFRP plate. However, it is difficult to cut free-form curves using a flexible circular saw. Therefore, in this research, a new technique that can cut free-form curves using a flexible circular saw was proposed. Then, a cutting test applying the technique was carried out.     

Rate acceleration of Diels–Alder reactions utilizing a fluorous micellar system in water

A fluorous micellar system in water has been created to produce a large interfacial area between these media that retains substrates, effectively facilitating intermolecular Diels–Alder reactions due to repulsion effects from both media. Because LiFOS functioned not only as a surfactant but also as a supporting electrolyte, an electrochemical approach could be introduced to evaluate the rate acceleration effects. The measurement of the particle size distribution of the fluorous micelles clearly supported these evaluations.     

Electroreductive block copolymerization of dichlorosilanes in the presence of disilane additives

The electroreductive polymerization of dichloromethylphenylsilane in the presence of triphenylsilyl group‐containing disilanes such as hexaphenyldisilane followed by the electroreductive termination with chlorotriphenylsilane afforded triphenylsilyl group‐terminated polymethylphenylsilane in 15–32% yield. The isolated polymethylphenylsilane (M_n = 3350 g mol^?1, M_w/M_n = 1.4) was found to react as a macroinitiator to copolymerize with dibutyldichlorosilane under electroreductive conditions producing the corresponding block copolymer (M_n = 4730 g mol^?1, M_w/M_n = 1.2) in 38% yield. The ratio of monomer units (? MeSiPh? to? BuSiBu? ) of the copolymer was determined to be 75:25 using ¹H NMR analysis, which was in good agreement with the calculated ratio (74:26) on the assumption that molecular weight of the macroinitiator was not changed. The block structure of the resulting copolymer, poly(methylphenylsilane)‐block‐poly(dibutylsilane), was also confirmed by comparing its ¹H NMR and UV absorption spectra with those of polymethylphenylsilane, polydibutylsilane and a statistical copolymer prepared by electroreductive polymerization of dichloromethylphenylsilane with dibutyldichlorosilane. This method is applicable to the preparation of other types of macroinitiator such as triphenylsilyl group‐terminated polydibutylsilane, and polydibutylsilane‐block‐polymethylphenylsilane was also obtained using this macroinitiator. Copyright © 2011 Society of Chemical Industry     

Computational fluid dynamics simulation of Hyperloop pod predicting laminar–turbulent transition

Railway Engineering Science - Three-dimensional compressible flow simulations were conducted to develop a Hyperloop pod. The novelty is the usage of Gamma transition model, in which the transition...     

Palladium‐Catalyzed Hydroxymethylation of Aryl‐ and Heteroarylboronic Acids using Aqueous Formaldehyde

Cyclometallated NHC palladium complexes prepared from palladium(II) acetate [Pd(OAc)₂] and unsymmetrical 1,3‐diarylimidazolinium salts catalyzed the hydroxymethylation of (hetero)arylboronic acids using an excess amount of formalin to afford (hetero)arylmethanols in good to satisfactory yields.

     

Photocarrier generation in organic thin-film solar cells with an organic heterojunction

Photocurrent–voltage characteristics for organic solar cells with a heterojunction formed between copper phthalocyanine and a perylene derivative (or C₆₀) were studied. The photocurrent was observed under both reverse and forward biases. From the analysis of the photocurrent action spectra, the origin of the reverse photocurrent was attributed to the excitons formed in both the organic layers, whereas that of the forward photocurrent was attributed to the excitons formed in the perylene derivative (or C₆₀) layer. The photocurrent density under reverse bias increased at higher temperatures, suggesting that the charge recombination possibility was lowered at higher temperatures. On the basis of the time responses of the photocurrents observed after pulsed photoirradiation, the charge separation and transport processes are discussed.     

Incidence of delayed onset infection after trabeculectomy with adjunctive mitomycin C or 5-fluorouracil treatment

AIMS/BACKGROUND: The introduction of the adjunctive use of antiproliferatives to trabeculectomy has greatly improved the success rate of this operation. Trabeculectomy with antiproliferative treatment, however, is usually associated with a cystic and thin walled filtering bleb, which may be more susceptible to infection. The objective of this study was to evaluate the incidence, clinical findings, and risk factors of delayed onset, bleb related infection after trabeculectomy with adjunctive mitomycin C (MMC) or 5-fluorouracil (5-FU) treatment. METHODS: The records of 632 glaucoma patients who underwent 966 trabeculectomies, with and without the use of adjunctive MMC or 5-FU treatment, between January 1985 and February 1995 were analysed. The mean follow up period was 3.5 (2.4) years (range 0.1 to 11.2 years). The mean patient age was 54.8 (18.8) years (range 0 to 88 years). RESULTS: Bleb related infection occurred in one of 76 trabeculectomies that did not receive antiproliferatives (1.3%), three of 228 treated with 5-FU (1.3%) trabeculectomies, and seven of 662 treated with MMC (1.1%). Five eyes developed blebitis; six eyes developed endophthalmitis. Bleb related infection developed an average of 3.1 (1.6) (range 0.4 to 6.0) years after trabeculectomy. All eyes had avascular or hypovascular blebs that were cystic in shape before infection and all eyes had reduced intraocular pressure. Early wound leaks and chronic, intermittent bleb leaks were identified to be risk factors for the bleb related infection. CONCLUSION: The incidence of delayed onset, bleb related infection after trabeculectomy with antiproliferative treatment is similar to that after trabeculectomy without antiproliferatives.     

Study on Shock Wave and Turbulent Boundary Layer Interactions in a Square Duct at Mach 2 and 4

In this paper, the outline of the Mach 4 supersonic wind tunnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach 2 and Mach 4 pseudo-shock waves in a square duct were investigated by color schlieren photographs and duct wall pressure fluctuation measurements. Finally, the wall shear stress distributions on the side, top and bottom walls of the square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear stress-sensitive liquid crystal visualization method. The side wall boundary layer separation region under the first shock is narrow near the top wall, while the side wall boundary layer separation region under the first shock is very wide near the bottom wall.     

A Dual Selection Module for Directed Evolution of Genetic Circuits

We have developed a genetic selection module which enables us to select for positive and negative expression of a gene by controlling the expression of two antibiotic resistance genes. This module can be used to tune the performance of genetic circuits that yield simple ON/OFF gene expression outputs depending on the environment (input). We have demonstrated the utility of the module by selecting a genetic inverter from a 200 fold excess of nonfunctional inverters in two rounds.