Fracture strength and behavior of carbon steel pipes with local wall thinning subjected to cyclic bending load

The power plant piping is designed to withstand seismic events using the design fatigue curve. However, the fatigue strength of a pipe with local wall thinning caused by erosion/corrosion is not clear. To evaluate the fatigue strength of pipes with local wall thinning, low cycle fatigue tests were conducted on 100A carbon steel pipes with local wall thinning. In load controlled tests on these pipes, ratcheting deformation was observed, and the fatigue strength became lower than that of cracked pipes. In displacement controlled tests, the fatigue strength of eroded pipes with 100 mm in eroded axial length, 0.5 in normalized eroded depth and 90° in eroded angle was almost equal to that given by the design fatigue curve in ASME B&PV Code Sec. III. To evaluate the local strain range in the maximum wall thinning area, the finite element analysis was conducted on the eroded pipes in the displacement controlled tests. It is concluded that the Mises strain range in the maximum wall thinning area and the low cycle fatigue curve can be used to conservatively estimate the low cycle fatigue life of an eroded pipe and the validity of estimated results can be confirmed experimentally.     

Angiotensin induces the urinary peristaltic machinery during the perinatal period

The embryonic development of mammalian kidneys is completed during the perinatal period with a dramatic increase in urine production, as the burden of eliminating nitrogenous metabolic waste shifts from the placenta to the kidney. This urine is normally removed by peristaltic contraction of the renal pelvis, a smooth muscle structure unique to placental mammals. Mutant mice completely lacking angiotensin type 1 receptor genes do not develop a renal pelvis, resulting in the buildup of urine and progressive kidney damage. In mutants the ureteral smooth muscle layer is hypoplastic and lacks peristaltic movements. We show that angiotensin can induce the ureteral smooth muscles in organ cultures of wild-type, but not mutant, ureteral tissues and that, in wild-type mice, expression of both renal angiotensin and the receptor are transiently upregulated at the renal outlet at birth. These results reveal a new role for angiotensin in the unique cellular adaptations of the mammalian kidney to the physiological stresses of postnatal life.     

Modeling and real‐time simulation of UPFC

We have developed a digital real‐time simulator of Power Electronics Controllers, so‐called FACTS (Flexible AC Transmission Systems) Controllers and/or Custom Power by using MATLAB^TM/SIMULINK^TM and dSPACE^TM System. This paper describes the modeling and the calculation accuracy of a UPFC (Unified Power Flow Controller) model. Hence, the developed simulator operates at a large time step, in order to improve simulation accuracy, a correction processing of the switching delay is implemented into the UPFC model. Calculation accuracy of the real‐time UPFC model is at the same level as EMTDC^TM results. We confirm stable operation of the developed UPFC model by connecting a commercial real‐time digital simulator (RTDS^TM). © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 19–26, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20200     

尿基复合肥中游离水的快速测定

直接把复合肥粉碎样加到卡尔·费休滴定容器中测定其游离水,省去萃取和离心步骤,简化了操作,分析结果重现性和准确度更高。     

Optimal network configuration of FRIENDS taking power supply reliability into account

FRIENDS (Flexible, Reliable and Intelligent ENergy Delivery System) is a new concept for a future power delivery system in which so‐called QCC (Quality Control Center) plays an important role to realize the customized power quality services and to connect a large number of distributed generators to distribution systems. In FRIENDS, QCCs are connected as a network through distribution cables to realize a reliable power supply. In this paper, a method to find the optimal network configuration of FRIENDS is proposed. The method can minimize the sum of facility installation cost and operational cost (distribution loss) under the constraint that the expected power interruption cost is less than a predetermined endurable value. The solution algorithm is based on tabu search, and employs a sensitivity analysis to select efficient facilities to be installed or to eliminate constraint violations. In the algorithm, single and double faults of power distribution system are taken into account to calculate the power supply reliability or expected power interruption cost. Several numerical real‐world examples are shown to demonstrate the validity of the algorithm. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 32–40, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20264     

Transfixion of cervical cord by a glass fragment--report of a case (author's transl)

Stab wound of the spinal cord caused by accident occurred in the home life is rare absolutely. One case of stab wound of the cervical spinal cord caused by penetrated and retained glass fragment within the spinal canal was reported. A 30-year-old woman was hospitarized on August 16, 1971. with complaint of left hemiparesis, gait disturbance and sensory impairment on the right side. A glass door fell down on the patient's neck on April 14, 1971. and one glass fragment was removed from the patient's left neck by one of the patient's family and no immediate spinal cord symptom appeared and no physician was consulted at that time. One and a half month after the injury the patient rod a motor bicycle and pain and severe stiffness in the shoulder and neck, and headache. These subjective symptom disappeared by rest and same subjective symptom repeated in following five days. Three and a half months after the injury the patient found sensation loss in the right foot and gait distrubance appeared. After the sensory impairment extended to the cervical level which was accompanied by left hemiparesis. On examination, the patient was found to have merked weakness of left limbs, spastic gait and severe impairment of touchpain- and thermosensation below the fifth cervical level but deep sensation was preserved. All tendon reflexes showed marked exaggeration and pathological reflexes were proved. Roentgenograms of the cervical spine revealed a long triangular glass fragment which had been retained in the spinal canal between the first and second cervical vertebrae. The air myelogram suggested the glass fragment had transfixed the cervical spinal cord. Laminectomy was performed and the glass fragment which had a shape of a sharp pointed surgical knife was removed by gentle move in the opposite direction of invation. Following removal of the foreign body, the patient's left hemiparesis recovered to normal state at four months after the operation and right sensory impairment also improved. The cervical spinal cord may be injured in the following way: the right lateral spinothalamic tract may be injured by the skewer injury due to glass fragment but injury of the left same tract may be avoided because of oblique direction of penetration of the glass fragment in the spinal cord. On the other hand, the left pyramidal tract may be compressed by glass fragment and not injured, because left hemiparesis recovered very well postoperatively.     

Element-free Galerkin method using directed graph and its application to creep problems

The element-free Galerkin method (EFGM) is one of the meshless methods proposed by Belytschko et al. Since node-element connectivities used in the finite element method (FEM) are not needed in the EFGM, the EFGM is expected to be applied to many problems of the continuum mechanics and to be utilized for a tool in a CAE system instead of the FEM. However the EFGM requires more CPU time to search nodes of the MLSM than the FEM. In this paper, the method of the directed graph and the Delaunay triangulation are respectively used for searching nodes and the division of the integral domain respectively. These techniques are useful for saving the CPU time and the simplification of the analysis for the EFGM. Furthermore, the EFGM has not been applied to nonlinear problems such as creep problems under elevated temperature. In this paper, the EFGM using the method of the directed graph and the Delaunay triangulation is applied to several creep problems. The CPU times for the analyses are reduced by the proposed EFGM. The results obtained from the EFGM analyses agree well with those of the FEM.     

A statistical interpretation of fatigue limit on the basis of the extreme theory

The theoretical consideration of the scatter of fatigue limit was made on the basis of the theory of extreme value. And then, the experimental examination on this theory was conducted through the various fatigue tests on induction-hardened low carbon steel specimens. As the results, it was found that the theory of extreme value is applicable to the interpretation of the scatter of fatigue limit.     

Thermodynamics of alcohol-unassociated active component liquid mixtures

An associated solution theory based on the UNIQUAC equation is developed to describe the excess properties of the alcohols in unassociated active components. The theory includes two association constants: the one for the alcohols, the other for alcohol-unassociated active component complexes. The theory reproduces well the activity coefficients of the ethanol—trichloromethane system having a maximum and a minimum and it also fits very skewed excess enthalpy curves for alcohol—benzene, alcohol—tetrachloromethane, etc. Prediction of ternary vapor—liquid and liquid—liquid equilibrium and excess enthalpy data has been carried out with good accuracy from binary parameters without adding any ternary constant.