Hotta Y.,Niigata Institute of Technology
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2011
This study assessed muscle fatigue during low-level contraction, which is sometimes difficult to observe. Surface EMG signals were recorded with monopolar and bipolar configurations during low-level isometric muscle contraction under a blood flow restriction condition (BFR condition) and a non-blood flow restriction condition (CON condition). As indices of fatigue, center frequency (CF) of the power spectral density (PSD) of the surface EMG and rating of perceived exertion (RPE) with the Borg CR-10 Scale were used. Results suggested that the monopolar configuration, which has a wider detection area relative than the bipolar one, was well suited for obtaining wave slowing accompanied by muscle fatigue. In addition, the monopolar configuration could detect differences in muscle condition in the BFR and CON conditions.
Yoshimoto Y.,Niigata Institute of Technology
Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B | Year: 2010
This paper investigates the performance, exhaust emissions, and combustion characteristics of a dual fuel diesel engine fueled by CNG (Compressed Natural Gas) as the main fuel. The experiments used two fuels for the ignition: one is OME (Oléate Methyl Ester), a major component of biodiesel, and the other is ordinary gas oil. The CNG supply rate was defined as the heat energy ratio of the supplied CNG to the total heat energy available in the cylinder. The results show that the conditions where operation with CNG/OME is possible are very similar to those of CNG/gas oil. When the CNG supply rate was raised to 75%, the brake thermal efficiency was similar to that of ordinary diesel operation at BMEP=0.65 MPa. When the CNG supply rate was higher than 75% ignition became very unstable and the brake thermal efficiency decreased significantly as well as the HC and NOx emissions increased sharply. The reason for this is considered to be that the appearance of miss fire cycles gave rise to combustion fluctuations.
Yoshimoto Y.,Niigata Institute of Technology
SAE Technical Papers | Year: 2010
This paper investigates the performance, exhaust emissions, and combustion characteristics of a dual fuel diesel engine fueled by CNG (compressed natural gas) as the main fuel. The experiments used a small single cylinder DI diesel engine and two kinds of fuels for the ignition: FAME (fatty acid methyl ester) fuels such as Methyl Oleate (OME) and OME-Methyl Palmitate (PME) blends, major components of biodiesel, and ordinary gas oil. The rate of the CNG supply was defined as the proportion of the heat energy of the supplied CNG to the total heat energy available in the cylinder. Compared with gas oil ignition, the FAME fuels had shorter ignition delays and significantly reduced smoke densities regardless of the PME contents. The PME contained in the FAME fuels gave rise to slight improvements in ignitability. The results also showed that the conditions where operation with CNG/FAME fuels is possible are very similar to those of the CNG/gas oil. When the CNG supply rate was raised to 75%, the brake thermal efficiency was similar to that of ordinary diesel operation at BMEP=0.67MPa. When the CNG supply rate was higher than 75% ignition became very unstable and the brake thermal efficiency decreased significantly as well as the HC and NOx emissions increased sharply. The reason for this is considered to be the appearance of misfiring, which gives rise to combustion fluctuations. Copyright © 2010 SAE International and Copyright © 2010 SAE Japan.
Ito K.,Niigata Institute of Technology
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2012
The center frequency (CF) of the power spectral density of a bipolar-configured surface electromyogram is typically used as an index of muscle fatigue. However, this index may be inadequate for measuring wave slowing due to muscle fatigue during low-level contractions. A previous study in which strong muscle fatigue was mimicked by compressing the proximal region of the forearm during isometric contractions showed that the differences in the degree of fatigue under compression and non-compression conditions were undetectable. The purpose of this study was to improve detection sensitivity of surface EMG variation caused by muscle fatigue using two approaches. The first approach employed recurrence quantification analysis (RQA) instead of traditional frequency analysis (FA) to compute the muscle fatigue index. The second approach employed a monopolar configuration for measuring surface EMG. We measured the surface EMG signal by using monopolar and bipolar configurations simultaneously during low-level isometric contractions under blood flow-restricted (BFR) and unrestricted (CON) conditions, and then compared and evaluated the detected differences in muscle fatigue. The results showed that the effect of BFR was better detected by RQA than by FA, and that the fatigability change was larger in the monopolar configuration than in the bipolar configuration.
Yoshimoto Y.,Niigata Institute of Technology |
Kinoshita E.,Kagoshima University |
Shanbu L.,Niigata Institute of Technology |
Ohmura T.,Niigata Diamond Electronic Co Ltd
Energy | Year: 2013
PME (Palm oil methyl ester) is a promising alternative fuel among biodiesels, because palm oil is the most produced feedstock and its yield is the highest among vegetable oil crops. However, PME has a serious drawback in its relatively high pour point. The aim of this investigation is to extend the range of utilization of PME by improving its low temperature fluidity. The present study used three kinds of blended fuels composed of PME/gas oil/1-butanol to show the effect of lower pour points. Neat PME has a pour point of 19°C, for a PME blend with 20% PME (PME20) the pour point is-5°C, and with 40 mass% 1-butanol blended into the PME20 the pour point is-10°C. Using four kinds of PME/gas oil blends as the base fuels the influence of 1-butanol addition on the engine performance, combustion characteristics, and exhaust emissions of a small single cylinder DI (direct injection) diesel engine was examined. The brake thermal efficiency of the base fuels changed little when 1-butanol was added up to 40 mass%. The results also showed that at the rated output condition the smoke emissions decreased considerably with increasing 1-butanol addition ratios. © 2012 Elsevier Ltd.