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Search Results: 1 - 10 of 890 matches for " Yasushi Kogo "
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New liquid crystals in the series of 1, 3, 5-triazine compounds containing azobenzene at the peripheral arms
A Salisu, A Kogo
Bayero Journal of Pure and Applied Sciences , 2010,
Abstract: Novel liquid crystal materials whose molecular structures consist of disc-like 1,3,5-triazine unit as a central core and three rod-like azobenzenes as the peripheral arms unit has been prepared and characterized by spectroscopic methods, and X-ray diffraction. The Series of compounds were prepared by nucleophilic addition of the primary amino nucleophile to 1,3,5-triazine electrophilic ring via alkyl spacers in presence of potassium carbonate as hydrochloride acceptor. Differencial scanning calorimetry (DSC), polarizing optical microscopy and x-ray diffraction confirmed Smectic mesophase textures of the materials. Increase in the polymethylene spacer length influence the thermal and phase stability of the compounds studied.
Effects of Pitavastatin on the Intima-Media Thickness of the Carotid Artery in Patients with Ischemic Stroke: The Pitavastatin Efficacy Study on Surrogate Markers and Imaging for Stroke (PESSMIST)  [PDF]
Yasushi Shibata
World Journal of Neuroscience (WJNS) , 2014, DOI: 10.4236/wjns.2014.44034

Pitavastatin is a strong statin that was developed in Japan. The clinical impact of pitavastatin treatment in patients with ischemic stroke has not been reported. We conducted a prospective, open label, clinical case-control study to determine the secondary preventive effects of pitavastatin for patients with cerebral infarction and hyperlipidemia. The pitavastatin group included 20 Japanese patients diagnosed with cerebral infarction and hyperlipidemia without previous statin intake. The control group included 22 patients diagnosed with cerebral infarction without hyperlipidemia. The pitavastatin group of patients received 2 mg of pitavastatin once a day after dinner. The mean age of the patients was 69.3 and 75.5 years for the pitavastatin and control groups, respectively, and the age of the pitavastatin group was significantly younger than that of the control group (P < 0.05). The serum TCho and LDL-C levels significantly decreased two months after the initiation of pitavastatin treatment. The mean and maximum intima-media thickness (IMT) also decreased after the initiation of pitavastatin. The mean and maximum IMT did not show any significant changes in the control group. The change of IMT %/year was less than zero for the pitavastatin group, and was almost zero or higher for the control group. Pitavastatin showed beneficial effects by improving the surrogate makers of stroke. These surrogate makers were effective to evaluate the efficacy of pitavastatin to prevent secondary stroke. Although a prospective randomized study is required to elucidate the long-term effects of pitavastatin, the current study suggests that pitavastatin may be effective to prevent secondary stroke in patients with stroke and hyperlipidemia.

Optimum-Welfare and Maximum-Revenue Tariffs in Vertically Related Markets  [PDF]
Yasushi Kawabata
Modern Economy (ME) , 2014, DOI: 10.4236/me.2014.55055

This paper compares the optimum-welfare tariffs with the maximum-revenue tariffs in a model of vertically related markets characterized by Cournot competition. It shows that the optimum-welfare tariff on the intermediate good exceeds the maximum-revenue tariff if the home intermediate-good firm is much more cost-competitive than the foreign intermediate-good firm. Further, the optimum-welfare tariff on the final good exceeds the maximum-revenue tariff if the home intermediate-good firm is significantly inefficient compared to the foreign intermediate-good firm. It is less likely that the optimum-welfare tariffs on the intermediate and the final good, respectively, exceed the maximum-revenue tariffs on the intermediate and the final good in the presence of vertical trade structures than in their absence.

Optimized Design of a Hybrid Biological Sewage Treatment System for Domestic Wastewater Supply  [PDF]
Benjamin K. Kogo, Elijah K. Biamah, Philip K. Langat
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.55002
Abstract: This study is aimed at evaluating alternative designs of waste stabilization ponds (WSPs) and constructed wetlands (CWs) for Kaputiei Housing Estate consisting of 2000 low cost housing units in Kenya. The entire analysis was carried out by simulating the effectiveness and purification efficiencies of WSPs and CWs in terms of Biological Oxygen Demand (BOD) reduction and faecal coliform (FC) removal under different scenarios of water treatment systems that included Re-sizing of the initial sewage treatment system, optimizing the design of the initial system and design of hybrid system for the estate. The graphic comparison of the simulated parameters under different scenarios showed that a hybrid design that combines both the WSPs and CWS provides an effluent BOD of 20 mg/l and 195 FC per 100 ml that meets the standard effluent discharge that is acceptable for unrestricted crop irrigation and thus will be reused in the housing estate for kitchen gardening and agroforestry.
Economic Evaluation Method of Photovoltaic Power Generation Installed in Ordinary Homes  [PDF]
Yasushi Iwasaki, Kayoko Yamamoto
Smart Grid and Renewable Energy (SGRE) , 2014, DOI: 10.4236/sgre.2014.56013

This study aims to develop an economic evaluation method for installing photovoltaic power generation in ordinary homes using GIS (Geographic Information Systems). The conclusions can be summarized in the following three points: 1) This method determines the profit and loss and payback period in order to evaluate the installation of photovoltaic power generation, taking into account the price of equipment, solar battery module conversion efficiency, subsidy, electricity purchase price, service life and rate for selling electricity. 2) The proposed evaluation method was applied to Kanagawa Prefecture in Japan, providing plural scenarios. Using a solar battery module conversion efficiency of more than 15%, it is possible to make the payback period shorter than the 20-year service life and anticipate a profit in almost the whole area. 3) The areas suitable for photovoltaic power generation are Kawasaki City and Ninomiya-machi. It is necessary to adopt measures to increase the subsidy and install photovoltaic power generating systems in specific places in areas where subsidies are not provided in enough amounts.

Transcervical Interstitial Microwave Ablation Therapy for the Treatment of Adenomyosis: A Novel Alternative to Hysterectomy  [PDF]
Yasushi Kanaoka, Hirosumi Imoto
Open Journal of Obstetrics and Gynecology (OJOG) , 2014, DOI: 10.4236/ojog.2014.414118
Abstract: Objectives: To investigate the clinical effects of transcervical interstitial microwave irradiation of adenomyotic tissues as an alternative to hysterectomy. Methods: Thirty-three patients who were candidates for hysterectomy for the treatment of adenomyosis associated with menorrhagia were treated by interstitial microwave irradiation using a specifically developed transabdominal ultrasound probe attachment for transcervical puncture along with microwave endometrial ablation, as an alternative to hysterectomy. Primary outcomes were changes in the venous hemoglobin level and the volume of the uterine body before and after treatment. Secondary outcomes were the visual-analogue scale (VAS) score for menorrhagia and dysmenorrhea after treatment. Results: At 3 months after surgery, the average hemoglobin level significantly increased by 4.6 g/dL. The volume of the uterine body significantly decreased to 53% and 52% of the volume before treatment at 3 and 12 months, respectively. VAS scores indicated an improvement in menorrhagia and dysmenorrhea. Conclusions: Transcervical interstitial microwave ablation therapy combined with microwave endometrial ablation reduced the uterine body volume and relieved menorrhagia and dysmenorrheal caused by adenomyosis. This strategy is a promising alternative to hysterectomy for the treatment of symptomatic adenomyosis.
A Sputtering Deposition of Al Enhances the Output Reproducibility in a Conducting Rubber Force Sensor  [PDF]
Masato Ohmukai, Yasushi Kami
Journal of Sensor Technology (JST) , 2016, DOI: 10.4236/jst.2016.63004
Abstract: Compressive force sensors or pressure sensors are indispensable to tactile sensors in humanoid robots. It is investigated that low-cost electro-conducting rubber sheets are applied to the force sensor, of which the biggest problem is its poor reproducibility. It was found that the aluminum deposition by a vacuum evaporation method shows excellent characteristics but suffers deterioration by a radiation heating effect. The aluminum electrode was deposited by a sputtering method, known to have an advantage of a low-temperature method, and the reproducibility of the output was improved.
Improvement of Fire Extinguishing Performance by Decentralized Supply of Fire-Fighting Agents  [PDF]
Yasushi Iwatani, Hiroyuki Torikai
Open Journal of Safety Science and Technology (OJSST) , 2017, DOI: 10.4236/ojsst.2017.73008
Abstract: One of the central problems in fire safety science and technology is to reduce damage caused by both fires and fire-fighting processes. This paper provides a potential solution to the problem, and it derives from decentralization of fire-fighting agents. In particular, this paper investigates fire extinguishing performance when a fire-fighting agent is supplied to a fire from one direction with one extinguisher and from two directions with two extinguishers. The two methods are called the centralized supply and the decentralized supply, respectively, in this paper. It is demonstrated that the decentralized supply reduces damage caused by both fires and fire-fighting processes. This follows from the facts that fire extinguishment by the decentralized supply is more certain than the centralized supply, and that the decentralized supply requires less total amount of a fire-fighting agent than the centralized supply for fire extinguishment.
Numerical Study on Heat Transfer Characteristics of Heated/Cooled Rods Having a Composite Board in between: Effect of Thermal Vias  [PDF]
Yasushi Koito, Toshio Tomimura
Journal of Electronics Cooling and Thermal Control (JECTC) , 2017, DOI: 10.4236/jectc.2017.74008
Abstract: By placing a sample between a heated and a cooled rod, a thermal conductivity of the sample can be evaluated easily with the assumption of a one-dimensional heat flow. However, a three-dimensional constriction/spreading heat flow may occur inside the rods when the sample is a composite having different thermal conductivities. In order to investigate the thermal resistance due to the constriction/spreading heat flow, the three-dimensional numerical analyses were conducted on the heat transfer characteristics of the rods. In the present analyses, a polymer-based composite board having thermal vias was sandwiched between the rods. From the numerical results, it was confirmed that the constriction/spreading resistance of the rods was strongly affected by the thermal conductivity of the rods as well as the number and size of the thermal vias. A simple equation was also proposed to evaluate the constriction/spreading resistance of the rods. Fairly good agreements were obtained between the numerical results and the calculated ones by the simple equation. Moreover, the discussion was also made on an effective thermal conductivity of the composite board evaluated with the heated and the cooled rod.
Effects of Terrain-Induced Turbulence on Wind Turbine Blade Fatigue Loads  [PDF]
Yasushi Kawashima, Takanori Uchida
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.913053
Abstract: Recently, the issue has surfaced that the availability factors for wind farms built on complex terrain are lower than the originally projected values. In other words, problems have occurred such as extreme decreases in generation output, failures of components inside and outside wind turbines including yaw motors and yaw gears, and cracking on wind turbine blades. As one of the causes of such issues, the effects of wind turbulence (terrain-induced turbulence) have been pointed out. In this study, we investigated the effects of terrain-induced turbulence on the structural strength of wind turbines through the measurement of strains in wind turbine blades and the analysis of wind data in order to establish a method for optimal wind turbine deployment that uses numerically simulated wind data and takes the structural strength of wind turbines into consideration. The investigation was conducted on Wind Turbine #10 of the Kushikino Reimei Wind Farm (in operation since Nov. 2012) in cooperation with Kyudenko New Energy Co., Ltd. Subsequently, we conducted numerical wind simulations (diagnoses of terrain-induced turbulence) to study the effects of the properties of airflow on the structural strength of wind turbines. For these simulations, the natural terrain version of the RIAM-COMPACT software package, which is based on large eddy simulation (LES), was used. The numerical simulations successfully reproduced the characteristics of the wind conditions and the structure of the three-dimensional airflow. These results enabled us to determine the threshold value for a turbulence index to be used for optimal wind turbine deployment planning that utilizes quantitative data from simulations with the natural terrain version of the RIAM-COMPACT software package.
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