1,057 research outputs found

    Estimation of a Multimass System Using the LWTLS and a Coefficient Diagram for Vibration-Controller Design

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    Vibration caused by mechanical resonance and time delay caused by signal detection and transmission degrade the control performance of a servo controller for a multimass mechanical system. A precise numerical model that represents resonance characteristics and time delay is necessary to design a desired control system. This paper presents an identification method using the iterative process of the linearized and weighted total least-squares method. The proposed method derives a transfer function without any prior knowledge of resonance characteristics and time delay. The order of the transfer function is determined with a coefficient diagram that shows coefficients of the denominator of the transfer function. Identification results with an experimental setup are shown to demonstrate the performance of the proposed method. A velocity servo controller with vibration-suppression control is designed with the transfer function, and control performance is verified with the experimental setup to validate the transfer function

    DDPWM-based power conversion system using three to four phase matrix converter for stand-alone power system

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    This paper presents a novel stand-alone power system using a three to four phase matrix converter (MC) for use with renewable energy sources such as a micro hydro turbine or a tiny wind turbine with a permanent magnet synchronous generator (PMSG). MCs are able to convert AC power to AC power directly without using DC link capacitors, and AC to DC conversion is also possible because DC is considered to be a type of AC power. Here, two single phase AC outputs with constant frequency and two DC outputs for a battery storage system are described for a fluctuating voltage source. Direct duty ratio pulse width modulation (DDPWM) is used to achieve the desired output because it is easy to expand an ordinary three to three phase MC to produce a three to four phase MC. In addition, fictitious reference iterative tuning (FRIT) is used to design the controller gains. The validity of the proposed method is demonstrated using MATLAB/Simulink simulations

    Premedication with midazolam in intellectually disabled dental patients: intramuscular or oral administration? A retrospective study

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    Background: The use of midazolam for dental care in patients with intellectual disability is poorly documented. The purpose of this study was to determine which method of premedication is more effective for these patients, 0.15 mg/kg of intramuscular midazolam or 0.3 mg/kg of oral midazolam. Material and Methods: This study was designed and implemented as a non-randomized retrospective study. The study population was composed of patients with intellectual disability who required dental treatment under ambulatory general anesthesia from August 2009 through April 2013. Patients were administered 0.15 mg/kg of midazolam intramuscularly (Group IM) or 0.3 mg/kg orally (Group PO). The predictor variable was the method of midazolam administration. The outcome variables measured were Observer’s Assessment of Alertness/ Sedation (OAA/S) Scale scores, the level of cooperation when entering the operation room and for venous cannulation, post-anesthetic agitation and recovery time. Results: Midazolam was administered intramuscularly in 23 patients and orally in 21 patients. More patients were successfully sedated with no resistance behavior during venous cannulation in Group PO than in Group IM ( p =0.034). There were no differences in demographic data and other variables between the groups. Conclusions: The results of this study suggest that oral premedication with 0.3 mg/kg of midazolam is more effective than 0.15 mg/kg of midazolam administered intramuscularly, in terms of patient resistance to venous cannulation. If both oral and intramuscular routes of midazolam are acceptable in intellectually disabled patients, the oral route is recommended

    Performance Improvement of a Portable Electric Generator Using an Optimized Bio-Fuel Ratio in a Single Cylinder Two-Stroke Engine

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    The performance of an electrical generator using bio-fuel and gasoline blends of different composition as fuel in a single cylinder engine is presented. The effect of an optimized blend ratio of bio-fuel with gasoline on engine performance improvement and thereby on the electrical generator output is studied. Bio-fuels such as ethanol, butanol and methanol are blended with gasoline in different proportions and evaluated for performance. The effects of different bio-fuel/gasoline blending ratios are compared experimentally with that of the gasoline alone using the output power developed by the electric generator as the evaluation parameter. With a composition of 10% ethanol–gasoline, the engine performance is increased up to 6% and with a blending ratio of 20% butanol–gasoline the performance is increased up to 8% compared to the use of 100% gasoline. The investigations are performed on a portable generator used in palm tree harvesting applications

    岡山大学における核燃料物質の安全管理のための劣化ウランと天然ウランの鑑別について

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    In Japan, the Law for the Regulation of Nuclear Source Materials, Nuclear Fuel Materials and Reactors (Regulation Law) controls the nuclear fuel materials such as thorium (Th), uranium (U) and plutonium (Pu). Under the Regulation Law, all related materials and reactors are needed to register to the Government. In Okayama University, many nuclear fuel materials, mainly uranium compounds, are registered and stored in 11 departments, separately. Discrimination between depleted uranium and natural uranium is important for the observance of the Regulation Law and the safety management of the nuclear fuel materials in the Okayama University. However, the discrimination of the two kind of uranium has poorly analyzed. In this study, we analyzed several uranium compounds by using γ-ray spectrometry to determine whether the depleted uranium or not

    Power mapping characteristic of double stator permanent magnet generator for electrical harvesting machine

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    The Malaysia's average of oil palm production have been increasing every year since last two decades. This is due to the increase global demands. Therefore, it is an urgent need to improve the harvesting productivity in the field. For such reasons, a harvesting machine had been developed to overcome this problem. This harvesting machine consists of DC motor and powered by electrical generator. Due to limitation of space and weight, Double Stator Permanent Magnet Generator (DSPMG) topology is being used. DSPMG has an advantage in producing high power density compared to conventional generator due to its large coil area. Sudden changes of current can be seen as the load changes when the harvester operates. Obviously, the generator performance needs to be studied. Therefore, this paper discusses on the performance of DSPMG by evaluating the power mapping characteristic. From the power mapping characteristic, the overall view of generator performance can be presented. The DSPMG shows that the highest output power (180W) can be achieved at load impedance of 10 Ω

    Sharp lines in the absorption edge of EuTe and Pb0.1_{0.1}Eu0.9_{0.9}Te in high magnetic fields

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    The optical absorption spectra in the region of the \fd transition energies of epitaxial layers of of EuTe and \PbEuTe, grown by molecular beam epitaxy, were studied using circularly polarized light, in the Faraday configuration. Under \sigmam polarization a sharp symmetric absorption line (full width at half-maximum 0.041 eV) emerges at the low energy side of the band-edge absorption, for magnetic fields intensities greater than 6 T. The absorption line shows a huge red shift (35 meV/T) with increasing magnetic fields. The peak position of the absorption line as a function of magnetic field is dominated by the {\em d-f} exchange interaction of the excited electron and the \Euion spins in the lattice. The {\em d-f} exchange interaction energy was estimated to be JdfS=0.15±0.01J_{df}S=0.15\pm 0.01 eV. In \PbEuTe the same absorption line is detected, but it is broader, due to alloy disorder, indicating that the excitation is localized within a finite radius. From a comparison of the absorption spectra in EuTe and \PbEuTe the characteristic radius of the excitation is estimated to be 10\sim 10\AA.Comment: Journal of Physics: Condensed Matter (2004, at press

    Evidence of mature adipocyte proliferation regulated by proliferin

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    Despite much research, whether mature adipocytes proliferate remains controversial. Here, we examined 5-bromo-2′-deoxyuridine (BrdU)-labelling of mature adipocytes. Although BrdU incorporation into subcutaneous adipocytes was less than that in visceral adipocytes, pioglitazone (Pio) treatment increased BrdU incorporation in subcutaneous, but not visceral, adipocytes in rats. Fully differentiated 3T3-L1 adipocytes exhibited an increase in cell number and BrdU incorporation with time, with this increase enhanced by Pio treatment. We therefore screened for genes that encode growth factors regulated by Pio, and selected proliferin (PLF). Both gene silencing of PLF by small interfering RNA and treatment with anti-PLF antibody suppressed proliferation in 3T3-L1 adipocytes. In adipocytes isolated from Pio-treated rats, the tissue-specific pattern of PLF expression was similar to that of BrdU incorporation. Administration of an anti-PLF antibody to mice reduced BrdU incorporation into adipocytes. Mature adipocytes thus have the ability to replicate, and this proliferation is positively regulated by PLF

    Radioactivity and radon emanation fraction of the granites sampled at Misasa and Badgastein

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    The chemical composition was analyzed and the radioactivity, radon exhalation rate and emanation fraction were measured to investigate the characteristics of the granites sampled at Misasa and Badgastein, world famous for radon therapy. The Misasa granite was probably composed of quartz, albite and microcline. The Badgastein granite was probably composed of quartz and muscovite. The radon exhalation rates and emanation fractions of the Misasa granite were much higher than those of the Badgastein granite, regardless of the Ra-226 activity concentrations

    The Combination of Gemcitabine, Cisplatin, and Paclitaxel as Salvage Chemotherapy for Advanced Urothelial Carcinoma

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    There is no standard second-line or salvage treatment for advanced urothelial carcinoma (UC). Here we investigated the efficacy and safety of gemcitabine, cisplatin, and paclitaxel (GCP) combination chemotherapy as salvage chemotherapy for advanced UC. We retrospectively analyzed the cases of 23 patients with advanced UC who showed progression or recurrence after cisplatin-based chemotherapy. Gemcitabine (1000 mg/m2), and paclitaxel (80 mg/m2) were administered on days 1 and 8. Cisplatin (70 mg/m2) was administered on day 1. The 3-week cycle regimen was repeated until disease progression if it had no intolerable toxicity. The overall response rate was 61% (95%CI, 41-78%). The median overall survival and progression-free survival times were 14 months and 5.5 months, respectively. Of the already known risk factors of chemotherapy for advanced UC, only the performance status was a prognostic factor for OS. Overall, 16 of the 23 patients (70%) experienced grade 3/4 toxicities, and no fatal adverse events were observed. GCP therapy was a promising option as second-line or salvage therapy for advanced UC
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