Global Search of a Three-dimensional Low Solidity Circular Cascade Diffuser for Centrifugal Blowers by Meta-model Assisted Optimization

A three-dimensional blade of a low solidity circular cascade diffuser in centrifugal blowers is designed by means of a multi-point optimization technique. The optimization aims at improving static pressure coefficient at a design point and at a small flow rate condition. Moreover, a clear definition of secondary flow expressed by positive radial velocity at hub side is taken into consideration in constraints. The number of design parameters for three-dimensional blade reaches to 10 in this study, such as a radial gap, a radial chord length and mean camber angle distribution of the LSD blade with five control points, control point between hub and shroud with two design freedom. Optimization results show clear Pareto front and selected optimum design shows good improvement of pressure rise in diffuser at small flow rate conditions. It is found that three-dimensional blade has advantage to stabilize the secondary flow effect with improving pressure recovery of the low solidity circular cascade diffuser.     

Increased proportion of medium chain fatty acids in nystatin-resistant yeast mutants

Fatty acid composition of phospholipids and steryl esters from four nystatin-resistant mutants ofSaccharomyces cerevisiae was compared to that from the wild strain. All the mutant strains which produce several ergosterol intermediates incorporated two-to three-fold as much medium chain fatty acids, especially 14:0 and 14:1 in phospholipids, and 12:0, 14:0 and 14:1 in steryl esters as the wild strain did. The increase in the relative amount of medium chain fatty acids in these mutants was found at all the growth temperatures and the growth phases examined, and in all the phospholipid species.     

Surface Friction of Poly(dimethyl Siloxane) Gel and Its Transition Phenomenon

The surface sliding friction of chemically cross-linked poly(dimethyl siloxane) (PDMS) swollen with linear PDMS as an oligomer is investigated. The friction force f increases with the normal pressure P in a power-law relation fP , where the exponent changes in a range of 0-1, depending on the degree of polymerization, N _poly, of the linear PDMS oligomer. When N _poly is in a range of 240-320, a dramatic decrease in friction force is observed at a critical normal pressure, P _c, leading to a very low friction coefficient on the order of 10^–3 at high-pressure ranges. The P _c increases with decreasing network size N _netof the gel and also with increasing polymer length related to N _poly. One possible explanation for this transition phenomenon in friction is that linear PDMS molecules are exuded from the gel network beyond a certain pressure and behave as polymer brushes, which are able to reduce the friction.     

Measurement of droplet size distribution in core region of high-speed spray by micro-probe L2F

In order to investigate the distribution of droplet sizes in the core region of diesel fuel spray, instantaneous measurement of droplet sizes was conducted by an advanced laser 2-focus velocimeter （L2F）. The micro-scale probe of the L2F is made up of two foci and the distance between them is 36 lain. The tested nozzle had a 0.2 mm diameter single-hole. The measurements of injection pressure, needle lift, and crank angle were synchronized with the measurement by the L2F at the position 10 mm downstream from the nozzle exit. It is clearly shown that the droplet near the spray axis is larger than that in the off-axis region under the needle full lift condition and that the spatial distribution of droplet sizes varies temporally. It is found that the probability density distribution of droplet sizes in the spray core region can be fitted m the Nukiyama-Tanasawa distribution in most injection periods.     

Remarkable improvement of NOx–PM trade-off in a diesel engine by means of bioethanol and EGR

In order to realize a premixed compression ignition (PCI) engine, the effects of bioethanol–gas oil blends and exhaust gas recirculation (EGR) on PM–NO_x trade-off have been investigated focusing on ignition delay, premixed combustion, diffusion combustion, smoke, NO_x and thermal efficiency. The present experiment was done by increasing the ethanol blend ratio and ethanol and by increasing the EGR ratio in a single cylinder direct injection diesel engine. It is found that a remarkable improvement in PM–NO_x trade-off can be achieved by promoting the premixing based on the ethanol blend fuel having low evaporation temperature, large latent heat and low cetane number as well, in addition, based on a marked elongation of ignition delay due to the low cetane number fuel and the low oxygen intake charge. As a result, very low levels of NO_x and PM, which satisfies the 2009 emission standards imposed on heavy duty diesel engines in Japan, were achieved without deterioration of brake thermal efficiency in the PCI engine fuelled with the 50% ethanol blend diesel fuel and the high EGR ratio. It is noticed that smoke can be reduced even by increasing the EGR ratio under the highly premixed condition.     

Inhibitory effects of an antiestrogen, toremifene, on the phorbol ester-induced adhesive capacity of breast carcinoma cells

Previous studies have revealed that protein kinase C (PKC) is responsible for malignant progression. In the present study, we investigated the potent inhibitory effects of an antiestrogen, toremifene, on PKC-mediated cellular adhesion. A phorbol ester, phorbol 12-myristate 13-acetate (PMA), significantly enhanced alpha2beta1 integrin-dependent adhesion of MCF-7 breast carcinoma cells. This PMA-induced adhesion was partially inhibited by incubating cells with toremifene prior to PMA exposure in a time- and dose-dependent manner. FACS analysis demonstrated that the PMA-induced alpha2beta1-dependent cellular adhesion was accompanied with elevated expression of alpha2beta1+integrin subunit on the cell surface. However, toremifene did not affect the elevated expression levels of these integrins but rather the avidity of alpha2beta1 integrin. We concluded that toremifene inhibited cellular adhesion activated by PMA, probably through mechanism which inhibits PKC.     

A case of recurrent breast cancer responding to combination therapy with mitoxantrone (MIT), 5'-deoxy-5-fluorouridine (5'-DFUR) and medroxyprogesterone acetate (MPA)

The patient was a 50-year-old woman who had undergone left standard radical mastectomy who had undergone left standard radical mastectomy on June 1, 1986. She showed multiple liver metastases with elevation of CEA level in July, 1991, and 5'-DFUR plus MPA combination therapy was started. The daily dosages were: 800 mg/body and 1,200 mg/body, respectively. After intra-arterial infusion of pirarubicin and Lipiodol, bilateral oophorectomy was performed and an implantable reservoir for intra-arterial infusion chemotherapy was implanted via the proper hepatic artery. Then she was treated by arterial-infusion of mitoxantrone 10mg/body intermittently every two weeks. The metastatic foci responded to this therapy and her CEA level decreased.     

Polishing and whitening properties of toothpaste containing hydroxyapatite

Toothpastes containing hydroxyapatite (HA-toothpaste) have demonstrated efficacy in preventing caries, treating hypersensitivity and curing periodontal diseases, however, their effects on whitening teeth have not been investigated. In this study, the polishing and whitening properties of hydroxyapatite contained toothpastes were evaluated in a combined experimental and clinical study. The polishing properties were evaluated in artificial teeth by polishing with different toothpastes, while the brightening and whitening properties were examined in volunteers using two colorimeters with two specially made fiberscopes. The results revealed that the addition of hydroxyapatite to toothpaste did not alter its polishing properties, while it did result in a marked increase in tooth-whiting. It was also found that the brightening and whitening properties increased as the amount of hydroxyapatite in the toothpaste increased. It is concluded that toothpaste containing hydroxyapatite are effective at whitening tooth and that whitening was not due to their polishing effect on tooth surface. © 2001 Kluwer Academic Publishers