• 제목/요약/키워드: A487

검색결과 1,473건 처리시간 0.027초

Numerical modeling of rapid impact compaction in loose sands

  • Ghanbari, Elham;Hamidi, Amir
    • Geomechanics and Engineering
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    • 제6권5호
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    • pp.487-502
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    • 2014
  • A three dimensional finite element model was used to simulate rapid impact compaction (RIC) in loose granular soils using ABAQUS software for one impact point. The behavior of soil under impact loading was expressed using a cap-plasticity model. Numerical modeling was done for a site in Assalouyeh petrochemical complex in southern Iran to verify the results. In-situ settlements per blow were compared to those in the numerical model. Measurements of improvement by depth were obtained from the in-situ standard penetration, plate loading, and large density tests and were compared with the numerical model results. Contours of the equal relative density clearly showed the efficiency of RIC laterally and at depth. Plastic volumetric strains below the anvil and the effect of RIC set indicated that a set of 10 mm can be considered to be a threshold value for soil improvement using this method. The results showed that RIC strongly improved the soil up to 2 m in depth and commonly influenced the soil up to depths of 4 m.

PERTURBATION OF DOMAINS AND AUTOMORPHISM GROUPS

  • Fridman, Buma L.;Ma, Daowei
    • 대한수학회지
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    • 제40권3호
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    • pp.487-501
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    • 2003
  • The paper is devoted to the description of changes of the structure of the holomorphic automorphism group of a bounded domain in \mathbb{C}^n under small perturbation of this domain in the Hausdorff metric. We consider a number of examples when an arbitrary small perturbation can lead to a domain with a larger group, present theorems concerning upper semicontinuity property of some invariants of automorphism groups. We also prove that the dimension of an abelian subgroup of the automorphism group of a bounded domain in \mathbb{C}^n does not exceed n.

Potential Profiles and Capacitances of an Ideally Polarizable Electrode/Hard Sphere Electrolyte System

  • Kim, Sang-Youl;Vedam, K.
    • Bulletin of the Korean Chemical Society
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    • 제11권6호
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    • pp.487-493
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    • 1990
  • A complete potential profile of an electrical double layer is calculated from a distribution function of charged particles based upon a model where the effect of a charged electrode and the finite size of ion are explicitly included. Electrons which are distributed on the electrode surface are assumed not to penetrate the electrode/electrolyte boundary. Formation of the constant density regions and their effects on potential and the electrical double layer capacitances are studied in great detail. The distribution of surface electrons as well as the constant density regions are found to be essential in characterizing the electrical double layer. The introduction of the ion size into the prior electrical double layer model of an ideally polarizable electrode/point charged electrolyte system, shows a great improvement in its characteristics mostly at negative potential region.

STUDY OF DYNAMICAL MODEL FOR PIEZOELECTRIC CYLINDER IN FRICTIONAL ANTIPLANE CONTACT PROBLEM

  • S. MEDJERAB;A. AISSAOUI;M. DALAH
    • Journal of applied mathematics & informatics
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    • 제41권3호
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    • pp.487-510
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    • 2023
  • We propose a mathematical model which describes the frictional contact between a piezoelectric body and an electrically conductive foundation. The behavior of the material is described with a linearly electro-viscoelastic constitutive law with long term memory. The mechanical process is dynamic and the electrical conductivity coefficient depends on the total slip rate, the friction is modeled with Tresca's law which the friction bound depends on the total slip rate with taking into account the electrical conductivity of the foundation both. The main results of this paper concern the existence and uniqueness of the weak solution of the model; the proof is based on results for second order evolution variational inequalities with a time-dependent hemivariational inequality in Banach spaces.

Rapidly Enlarging Pediatric Cortical Ependymoma

  • Yamasaki, Kouji;Yokogami, Kiyotaka;Yamashita, Shinji;Takeshima, Hideo
    • Journal of Korean Neurosurgical Society
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    • 제57권6호
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    • pp.487-490
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    • 2015
  • We report a 10-year-old boy with supratentorial cortical ependymoma that rapidly grew in the course of 3 years. He suffered generalized seizures when he was 5 years old; MRI showed a small cortical lesion in the right postcentral gyrus. MRI performed 2 years later revealed no changes. For the next 3 years he was free of seizures. However, at the age of 10 he again suffered generalized seizures and MRI disclosed a large parietal tumor. It was resected totally and he remains free of neurological deficits. The histopathological diagnosis was ependymoma. Pediatric supratentorial cortical ependymomas are extremely rare. We recommend including cortical ependymoma as a differential diagnosis in pediatric patients with cortical mass lesions presenting with seizures and careful follow-up even in the absence of symptoms because these tumors may progress.

Estimation for the Time-t Discounted Price of Multiple Defaultable Zero Coupon Bond

  • Park, Heung-Sik
    • Communications for Statistical Applications and Methods
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    • 제16권3호
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    • pp.487-493
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    • 2009
  • We consider a multiple defaultable zero coupon bond. Assuming defaults occur according to a marked point process, we explain how to estimate the time-t discounted price of zero coupon bond by simulation. For the special case of a given specific random face value, we show that the real probability measure is the risk neutral probability measure. In this case the time-t discounted conditional price can be obtained by observing a single sample path upto the time t in the real world. Furthermore the time-t discounted price can be estimated by observing real situations or by simulation under the real probability measure.

Analysis and Design of Separated Permanent-Magnet Actuator for 225AF Molded Case Circuit Breaker

  • Park, Hyeon-Jeong;Kim, So-Hyun;Ro, Jong-Suk;Jung, Hyun-Kyo
    • Journal of international Conference on Electrical Machines and Systems
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    • 제3권4호
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    • pp.487-490
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    • 2014
  • The conventional motor-driven MCCB (molded-case circuit breaker) is not only large in size, but also inefficient in performance. To solve these problems, this paper suggests SPMA (separate permanent-magnet actuator), a novel magnetic actuator. In this paper, SPMA is designed for a 225AF MCCB and compared to a conventional motor-driven MCCB and to an EMFA (electro-magnetic force driving actuator)-type MCCB.

Phthirus pubis Infestation of the Scalp: A Case Report and Review of The Literature

  • Veraldi, Stefano;Pontini, Paolo;Nazzaro, Gianluca
    • Parasites, Hosts and Diseases
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    • 제56권5호
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    • pp.487-489
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    • 2018
  • Phthirus pubis usually infests the pubis, groin, buttocks and perianal region. It can sometimes infest the thighs, abdomen, chest, axillae and beard. Eyelashes and eyebrows may be involved in children. The involvement of the scalp is very rare. We describe a case of P. pubis infestation located exclusively on the scalp in an adult woman. Neither lice/nits nor skin lesions were observed elsewhere, including eyebrows, eyelashes, axillae, pubis, buttocks and perianal region (the patient was hairless in the axillae and pubis). A review of the literature is enclosed.

수정진동자를 사용한 점탄성 유체의 점성계수와 전단 탄성계수 측정에 관한 이론해석 (Theoretical Analysis for the Measurement of Viscosity and Shear Modulus of Viscoelastic Fluids by Using a Quartz Crystal Oscillator)

  • 서용권;김영한
    • 대한기계학회논문집B
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    • 제32권7호
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    • pp.487-496
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    • 2008
  • Quartz crystal oscillator is frequently used in measuring a very small amount of mass attached to or adsorbed on the surface of an electrode on the quartz plate. The physical principle is that the resonance frequency of the shear vibration of the quartz caused by an applied electric field is a function of the mass. Recently, effort has been tried to measure physical properties of viscoelastic fluids, such as viscosity and shear modulus. This paper presents useful formula that can be used in estimating the properties of viscoelastic fluids. Important finding in this analysis is that the formula can produce multiple values for the physical properties of the viscoelastic materials.

A Recurrent Cellular Schwannoma

  • Kim, Eung Re;Choi, Eun Oh;Lee, Kyung Bun;Kang, Chang Hyun;Kim, Young Tae;Park, In Kyu
    • Journal of Chest Surgery
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    • 제47권5호
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    • pp.487-490
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    • 2014
  • Cellular schwannoma is an uncommon variant of schwannomas that can occur in a peripheral nerve. Although cellular schwannomas typically do not differ in prognosis from regular schwannomas, they are known to cause local recurrence when not completely resected. Here, we report the case of a patient with cellular schwannoma of the posterior mediastinum, which recurred after 13 years.