643 research outputs found

    Cases Histories and Recent Development of the Sand Compaction Pile Method as a Countermeasure Against Liquefaction

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    The Sand Compaction Pile (SCP) method is the most useful countermeasure against liquefaction in Japan. The investigation on the effectiveness of improved ground by the SCP method suffered from the past large-scale earthquakes (the 1993 Kushiro-Oki Earthquake, the 1994 Hokkaido Toho-Oki Earthquake, the 1995 Hyogo-ken Nambu Earthquake etc.) were conducted and found that the behavior of the compacted ground apparently differ from unimproved one. Especially less subsidence occurred on the compacted area compared with the unimproved area at Port Island and Rokko Island during even the 1995 Hyogo-ken Nambu (Kobe) earthquake. The conventional SCP method aims to increase the bearing capacity of soft ground by reinforcing it as compacted ground, or by increasing the density of loose sandy ground, through the vibratory installation of additional sand piles. However, the use of a vibro-hammer generates noise and vibration, which may adversely affect the surrounding environment. It is therefore difficult to use this method for ground improvement work in urban areas or on sites close to existing structures. To reduce noise and vibration, the non-vibratory SCP method which is based on a rotary penetration system using a forced lifting/driving device and a rotary drive motor were developed. This paper describes the case histories during the past large-scale earthquakes and newly development (objectives, applications etc.) of the SCP method applied as a countermeasure against liquefaction in Japan

    3-D finite element analysis of coupling current in multifilamentary AC superconducting cable

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    A method for analyzing the 3-D coupling current which is induced by an AC magnetic field in a multifilamentary superconducting cable is developed. In this method, such a superconducting cable, in which many twisted filaments are embedded in a matrix, is treated as macroscopic, having anisotropic conductivity. The method for treating the anisotropy of conductivity and the 3-D finite-element formulation are presented. The effectiveness of the technique is illustrated by the analysis of the 3-D coupling currents of superconducting cables.</p

    Local ras and ros in the hypertrophic differentiation of chondrocytes

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    Newsletter of the Boston University School of Medicine, Student American Medical Association (SAMA

    Hemodynamic Assessment of Celiaco-mesenteric Anastomosis in Patients with Pancreaticoduodenal Artery Aneurysm Concomitant with Celiac Artery Occlusion using Flow-sensitive Four-dimensional Magnetic Resonance Imaging

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    ObjectivesMany pancreaticoduodenal artery (PDA) aneurysms are associated with celiac artery (CA) stenosis. The pathogenesis of PDA aneurysm may be associated with hemodynamic changes due to CA stenosis/occlusion. The aim of this study was to assess the hemodynamic changes of celiaco-mesenteric anastomosis in patients with PDA aneurysms concomitant with CA occlusion using four-dimensional flow-sensitive magnetic resonance imaging (4D-Flow).Methods4D-Flow was performed preoperatively on five patients. Seven age- and sex-matched individuals were used as controls. Hemodynamic parameters such as flow volume and maximum flow velocity in PDAs, gastroduodenal arteries, common hepatic arteries, and superior mesenteric arteries were compared between both groups. Wall shear stress (WSS) and oscillatory shear index (OSI) were mapped in both groups.ResultsIn the patient group, 4D-Flow identified retrograde flow of both gastroduodenal arteries and common hepatic arteries. Heterogeneous distribution patterns of both WSS and OSI were identified across the entire PDA in the patient group. OSI mapping showed multiple regions with extremely high OSI values (OSI > 0.3) in all patients. All PDA aneurysms, which were surgically resected, were atherosclerotic.Conclusions4D-Flow identified hemodynamic changes in celiaco-mesenteric arteries in patients with PDA aneurysms with concomitant CA occlusion. These hemodynamic changes may be associated with PDA aneurysm formation

    Tumour enhancement with newly developed Mn-metalloporphyrin (HOP-9P) in magnetic resonance imaging of mice

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    The purpose of the study is to evaluate the tumour enhancing characteristics and biodistribution of a newly developed metalloporphyrin derivative, HOP-9P (13, 17-bis (1-carboxypropionyl) carbamoylethyl-3, 8-bis (1-phenylpropyloxyethyl)-2,7,12,18-tetra- methyl-porphynato manganese (III)). Seven mice bearing SCC VII tumours were imaged using T1-weighted conventional spin echo magnetic resonance images before and 5 min, 2 h and 24 h after intravenous injection of 0.1 mmol/kg of HOP-9P. For the acquired images, signal intensities of the tumour, muscle and oil-phantom were measured. Then, tumor/oil and tumor/muscle signal intensity ratios were calculated. Nineteen mice were sacrificed before or after the administration of HOP-9P (at 5 min, 2 h and 24 h), and the biodistribution of manganese in the tumour, muscle, liver, blood and kidneys was measured using optical emission spectrometers and was expressed as micrograms of manganese per gram of tissue. The tumour/muscle signal intensity ratio at 24 h (3.18 ± 0.34) was significantly higher than precontrast ratio (1.77 ± 0.20) (P < 0.05). The biodistribution assessment of manganese demonstrated that HOP-9P gradually and consistently accumulated in the tumour to reach the highest concentration at 24 h (3.49 ± 1.22 μ gMn/g). It is concluded that HOP-9P is a potential tumour-specific MR contrast agent. © 2001 Cancer Research Campaign http://www.bjcancer.co

    3-D time-periodic finite element analysis of magnetic field in non-oriented materials taking into account hysteresis characteristics

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    Problems in analyzing 3-D stationary nonlinear magnetic field in non-oriented material taking into account hysteresis characteristics and eddy current, such as finite element formulation and convergence of nonlinear iteration, are discussed</p

    Numerical and experimental investigations of current distribution at the joint between AC superconducting cable and normal conducting plate

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    The effect of the configuration of the joint between an ac superconducting cable and a normal conducting plate on the current distribution and the joule loss is investigated by using the 3-D finite element method. It is shown that the concentration of current can be reduced by changing the configuration of joint. The effectiveness of the analysis is verified by measuring the current distribution on the surface of a copper plate and the quenching current </p
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