Influence of output power out of a synchronous generator installed in a customer system on current limiting effects due to a fault current limiter

In this paper, it was assumed that a synchronous generator in a customer system was connected to a distribution system via the fault current limiter (FCL). We theoretically investigated the influence of the output power of the generator on the limiting effect of the fault current when a three‐phase short‐circuit fault occurs. It was shown that the fault current out of the customer system, limited by the FCL, rises with the output power of the generator. It was found that the larger the output, the higher the fault current at the fault point is when the limiting resistance is less than 15 Ω in the case of the resistive‐type FCL. On the other hand, the fault current at the fault point decreases with an increase in the output power for a limiting resistance more than 15 Ω. In contrast, it was found that the suppressing effect on the fault current at the fault point due to the inductive‐type FCL hardly depends on the output power. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(3): 15–24, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10357     

p27 Is a Critical Prognostic Biomarker in Non-Alcoholic Steatohepatitis-Related Hepatocellular Carcinoma

Non-alcoholic steatohepatitis (NASH) is a recently identified chronic liver disease, which progresses to liver cirrhosis and hepatocellular carcinoma (HCC). As the number of patients studied to date has been limited, clinically useful prognostic biomarkers of NASH-related HCC have not been available. In this study, we investigated the status of a cell-cycle regulator, p27, in NASH-related HCC. p27 has been regarded as a prognostic factor in various types of cancer patients. A total of 22 cases with NASH-related HCC were analyzed for p27 protein expression, and phosphorylation at threonine 157 (T157) and serine 10 (S10) by immunohistochemical analysis. The correlation of p27 with tumor characteristics, disease-free survival (DFS), and overall survival was analyzed. p27 expression was decreased in 13 HCCs (59%), and was significantly correlated with enlarged tumor size (p = 0.01) and increased cell proliferation (p < 0.01). Phospho-p27 at T157 and S10 was detected in four (18%) and seven (32%) cases, respectively, and patients positive for phospho-p27 (S10) showed reduced DFS (hazard ratio 7.623, p = 0.016) by univariate analysis. Further studies with more patients are required to verify the usefulness of p27 as a biomarker for predicting tumor recurrence in NASH patients.     

Risk assessment for optimum low‐voltage distribution facilities constructed by using genetic algorithms

The influences of uncertainty of the load growth rate and interest rate on the total cost of low‐voltage distribution facilities was investigated. We assumed that the total cost was composed of the initial construction cost, the improvement cost, and the cost of power loss. We also assumed that the distribution facilities were operated for 30 years. Genetic algorithms were used to determine how to construct cost‐effective distribution facilities that did not compromise power quality. Two investment methods were compared: one in which the utility cut down the initial construction cost and improves the initial facilities along with the load growth, and one in which the utility bears the large initial cost without the improvement cost. It was found that the lower cost method depends on the load growth rate and the interest rate. It was also found that the influence of uncertainty in the load growth rate increases with an increase in the differential between the actual load growth rate and the expected one. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(2): 10–19, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20976     

Distribution voltage rise at dense photovoltaic generation area and its suppression by SVC

An SVC is proposed as a reactive power compensation device to suppress the rise in the customer voltage due to photovoltaic power generation systems. The SVC produces a reactive power by controlling a thyristor. The effect of the SVC on the rise in the customer voltage has been investigated. Calculation results show that installing an SVC on the low‐voltage side is more effective for suppressing the rise in the customer voltage compared to an SVC located on the high‐voltage side. As far as the calculation conditions are concerned, it is found that the rated capacity of the SVC needed to maintain the customer voltage within 101±6V is over ±11.1kVA. The slope reactance required to suppress the customer voltage lower than 107 V is found to be under 1.28%. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(2): 47–53, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20478     

Safety assessment of genetically engineered potatoes with designed soybean glycinin: compositional analyses of the potato tubers and digestibility of the newly expressed protein in transgenic potatoes

The compositions of transgenic potatoes with intact and modified genes for soybean glycinin were compared with those of control potatoes; non-transgenic or transgenic ones with a vector. The expression levels of glycinin proteins in the transgenic potato tubers were approximately 12–31 mg g⁻¹-total soluble protein. With reference to six major components, moisture, protein, lipid, fiber, ash and carbohydrate, there were no significant differences between transgenic and control potatoes. The levels of glycoalkaloids in transgenic potato tubers, as well as in transgenic controls, increased in comparison with those in non-transgenic ones, though the level was within the permitted limit. The modified glycinin expressed in the transgenic potato tuber was digested under the simulated gastric conditions. From these results, the transgenic potatoes with intact and modified glycinin genes are considered to be as safety utilization for food as non-transgenic potatoes. © 1999 Society of Chemical Industry     

Enhancement of nucleate boiling on composite surfaces

A composite heating surface composed of materials with different thermal conductivities can be expected to enhance heat transfer in nucleate boiling. This is because the end surface, with higher conductivity, will attain a higher temperature and as a result will serve to provide preferential nucleation sites. To confirm this idea, several composite surfaces were fabricated by uniaxially imbedding thin copper cylinders in the heat flow direction on a stainless steel circular plate 30 mm in diameter and 5 mm thick. The imbedded copper cylinders ranged from 1 mm to 4 mm in diameter and one to 77 in number. The heat transfer performance of these composite surfaces was investigated for pool boiling of saturated water at atmospheric pressure. It was confirmed that the copper cylinder surfaces exposed to water functioned as local hot spots to initiate preferential nucleate boiling, leading to higher boiling heat transfer coefficients than those on a homogeneous stainless steel surface. The measured void fraction above the heating surface verified intensive bubble generation on the surface of the copper cylinders. This situation continued up to a certain heat flux level and was then followed by nucleation on the mother surface of stainless steel around the copper cylinders. A numerical analysis of heat conduction within a composite wall simulated the temperature distribution within the wall and the variation in surface heat flux at the time of boiling incipience. © 1998 Scripta Technica, Heat Trans Jpn Res, 27(3): 216–228, 1998     

配电系统二线短路时故障电流抑制效果的模拟

研究了在配电系统中引入限流器后的系统行为。假设二线短路故障分别发生在电源侧母线出口和负荷馈线末端,在三点分别设置了限流器,利用ＥＭＴＰ软件对限流器的故障电流抑制效果进行了模拟。结果表明限流器的引入具有明显的限流效果,并可改善因故障引起的母线电压瞬时降低。     

Discharge of a shock wave from an open end of a tube

IntroductionWhen a Pressure wave such as the shock waveprOPagates along a constant area straight tube andreaches at the open end, an impulsive wave is emittedOutward from the tube exit toward the surrounding areaand causes an impulsive noise laal a sonic boomproduced by a supersonic aircraft. Therefore, someauthors have investigated the discharge of a weakcompression wave from an open end in order to reducethe impulsive noise in relation to'the high speed railWaytUImel in the previous paped'…     

Temperature distribution on inclined plate caused by interaction with supersonic jet

IntroductionThe phenomena of the impingement of a supersonicjet on a solid obstacle is very interesting and importantin relation to the aeronautical and other industrialengineerings[']-l']. A large number of papers hadconcerned with the impingement on a perpendicularplate and evidenced the flow phenomena and thepressure distribuhon on a plate and so on. However, theinvestigation of the impingement on an inclined platecan only be found in merely several papers['-']. Ih thesestudies, it is menti…