• Title/Summary/Keyword: internal force

Search Result 997, Processing Time 0.028 seconds

Analytical study on cable shape and its lateral and vertical sags for earth-anchored suspension bridges with spatial cables

  • Gen-min Tian;Wen-ming Zhang;Jia-qi Chang;Zhao Liu
    • Structural Engineering and Mechanics
    • /
    • v.87 no.3
    • /
    • pp.255-272
    • /
    • 2023
  • Spatial cable systems can provide more transverse stiffness and torsional stiffness without sacrificing the vertical bearing capacity compared with conventional vertical cable systems, which is quite lucrative for long-span earth-anchored suspension bridges' development. Higher economy highlights the importance of refined form-finding analysis. Meanwhile, the internal connection between the lateral and vertical sags has not yet been specified. Given this, an analytic algorithm of form-finding for the earth-anchored suspension bridge with spatial cables is proposed in this paper. Through the geometric compatibility condition and mechanical equilibrium condition, the expressions for cable segment, the recurrence relationship between catenary parameters and control equations of spatial cable are established. Additionally, the nonlinear general reduced gradient method is introduced into fast and high-precision numerical analysis. Furthermore, the analytic expression of the lateral and vertical sags is deduced and discussed. This is very significant for the space design above the bridge deck and the optimization of the sag-to-span ratio in the preliminary design stage of the bridge. Finally, the proposed method is verified with the aid of two examples, one being an operational self-anchored suspension bridge (with spatial cables and a 260 m main span), and the other being an earth-anchored suspension bridge under design (with spatial cables and a 500 m main span). The necessity of an iterative calculation for hanger tensions on earth-anchored suspension bridges is confirmed. It is further concluded that the main cable and their connected hangers are in very close inclined planes.

Performing Inauthenticity: The Crisis of Asian America and Alternative Identity Politics ("가짜로 살아가기" -정체성으로서의 '아시아계 미국인'의 위기와 대안)

  • Im, Kyeong Kyu
    • Journal of English Language & Literature
    • /
    • v.56 no.5
    • /
    • pp.773-796
    • /
    • 2010
  • This essay examines, first, the possibility and limitation of Asian America as a category of identity and its political and cultural implications through various theoretical perspectives. Here, by closely reading David Mura's poem "The Colors of Desire," I will argue that "Asian America" as a category of identity is now on the verge of falling apart and its politics of identity is no longer an effective way of fighting back against racism in the US. It is because Asian America is indeed what might be called a historical block, a product of ad-hoc coalition between different ethnic groups historically situated and constructed. In this sense, it is a kind of phantasmal object that is marked by practical absence. This fabricatedness inherent in Asian America as an identity category signifies that it has no essence that is meant to define the group in a transcendental way. The internal totality and coherence of that identity can thus be achieved only by suppressing differences between various ethnic groups and positing a single 'authentic' Asian American identity and culture. More dangerously, according to Viet Nguyen, such idealization of a single subject position can reinforces ideological rigidity that might threaten the ability of Asian America to represent itself in a unified fashion. Then, he predicts, Asian America will lose its cohesive force and fall apart. Eventually, every group within Asian America will be ethnicized. The only way of escaping from this bleak situation, as Vincent Cheng argues, is to foregroud the fabricatedness and ad-hocness of Asian America and to perform "inauthenticity," because Asian America is nothing but a functional category that is marked by absence of essence or authenticity. If Asian Americans admit that they have no essence and that they are essentially inauthentic, the practice of performing inauthenticity can become what we might call an alternative Asian American culture and identity.

Effect of Flexural Performance on U-Shaped Precast Concrete Beams with Noncontact Lapped Splice (비접촉 겹침 이음된 프리캐스트 U형 보의 휨성능에 미치는 효과)

  • Ha, Sang-Su;Kim, Seung-Hun
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.12 no.6
    • /
    • pp.119-128
    • /
    • 2008
  • In this study, new moment-resisting precast concrete beam-column joint is proposed for moderate seismic regions. It has the connection reinforcing bars, penetrated the joint and lap-spliced with the bottom bars of precast U-shaped PC beam. To evaluate the performance for noncontact lapped splice, experimental and analytical works were conducted. Major variables for tests are the length of lap, the diameter of connection reinforcing bars, and the distance between lapped bars. Analytic research was performed nonlinear finite element method. Analytic research focused on crack pattern, load-deflection curve, comparison of internal force, evaluation of ductility strains of reinforcement bar. Results of experimental and analytical works show that the these variables has much influence on flexural strength and ductility, and joint behavior.

Insertions of the striated muscles in the skin and mucosa: a histological study of fetuses and cadavers

  • Ji Hyun Kim;Gen Murakami;Jose Francisco Rodriguez-Vazquez;Ryo Sekiya;Tianyi Yang;Sin-ichi Abe
    • Anatomy and Cell Biology
    • /
    • v.57 no.2
    • /
    • pp.278-287
    • /
    • 2024
  • Striated muscle insertions into the skin and mucosa are present in the head, neck, and pelvic floor. We reexamined the histology of these tissues to elucidate their role in transmission of the force. We examined histological sections of 25 human fetuses (gestational ages of ~11-19 weeks and ~26-40 weeks) and 6 cadavers of elderly individuals. Facial muscle insertion or terminal almost always formed as an interdigitation with another muscle or as a circular arrangement in which muscle fiber insertions were sandwiched and mechanically supported by other muscle fibers (like an in-series muscle). Our examination of the face revealed some limited exceptions in which muscle fibers that approached the dermis were always in the nasalis and mentalis muscles, and often in the levator labii superioris alaeque nasi muscle. The buccinator muscle was consistently inserted into the basement membrane of the oral mucosa. Parts of the uvulae muscle in the soft palate and of the intrinsic vertical muscle of the tongue were likely to direct toward the mucosa. In contrast, the pelvic floor did not contain striated muscle fibers that were directed toward the skin or mucosa. Although 'cutaneous muscle' is a common term, the actual insertion of a muscle into the skin or mucosa seemed to be very rare. Instead, superficial muscle insertion often consisted of interdigitated muscle bundles that had different functional vectors. In this case, the terminal of one muscle bundle was sandwiched and fixed mechanically by other bundles.

Effects of Insamjungchuntang on the Respiratory System in Experimental Animals (인삼정천탕(人蔘定喘湯)이 호흡기계(呼吸器系)에 미치는 영향(影響))

  • Kim, Ho-Soon;Shin, Jo-Young
    • The Journal of Internal Korean Medicine
    • /
    • v.19 no.1
    • /
    • pp.409-427
    • /
    • 1998
  • Insamjungchuntang has been used in Korea for many centuries as a treatment for respiratory disease. The effect of Insamjungchuntang on tracheal smooth muscle is not known. The purpose of the present study is to determine the effect of Insamjungchuntang on histamine and acetylcholine induced tracheal smooth muscle contraction in rats and guinea pigs. Guinea pig (500 g, male) and Sprague Dawley rats (200 g, male) were killed by $CO_2$ exposure and a segment (8-10 mm) of the thoracic trachea from each rat and guinea pig was cut into equal segments and mounted 'in pairs' in a tissue bath. Contractile force was measured with force displacement transducers under 0.5 g loading tension. The dose of histamine (His) and acetylcholine (Ach) which evoked 50% of maximal response $(ED_{50})$ was obtained from cumulative dose response curves for histamine and acetylcholine$(10^{-7}{\sim}10^{-4}\;M)$. Contractions evoked by His ($ED_{50}$) and Ach $(ED_{50})$ were inhibited significantly by Insamjungchuntang. In guinea pig tracheal smooth muscle, the mean percent inhibition of acetylcholine induced contraction was $38.58\(p<0.05)\;after\;10{\mu}l/ml$ Insamjungchuntang, $90.75\(p<0.01)\;after\;30{\mu}l/ml$. Insamjungchuntang and $133.17\(p<0.01)\;after\;100{\mu}l/ml$ Insamjungchuntang. In rat tracheal smooth muscle, the mean percent inhibition of acetylcholine induced contraction was $10.0\(p<0.05)\;after\;10{\mu}l/ml$ Insamjungchuntang, $80.71\(p<0.01)\;after\;30{\mu}/ml$ Insamjungchuntang and $118.29\(p<0.01)\;after\;100{\mu}l/ml$ Insamjungchuntang. Also, in guinea pig tracheal smooth muscle, the mean percent inhibition of histamine induced contraction was $45.5\(p<0.01)\;after\;10{\mu}l/ml$ lnsamjungchuntang, and $93.17\(p<0.01)\;after\;30{\mu}l/ml$. lnsamjungchuntang $134.50\(p<0.01)\;after\;100{\mu}l/ml$ Insamjungchuntang. In rat tracheal smooth muscle, the mean percent inhibition of histamine induced contraction was $37.83\(p<0.01)\;after\;10{\mu}l/ml$ lnsamjungchuntang, $90.5\(p<0.01)\;after\;30{\mu}l/ml$ Insamjungchuntang and $135.17\(p<0.01)\;after\;100{\mu}l/ml$ Insamjungchuntang. Propranolol $(10^{-7}\;M)$ slightly but significantly attenuated the inhibitory effects of Insamjungchuntang. Following treatment with propranolol, the mean percent inhibition caused by $100{\mu}l/ml$. Insamjungchuntang fell to 46.42% in guinea pig induced by acetylcholine contraction and by $100{\mu}l/ml$ Insamjungchuntang fell to 5.43% (p<0.05) in rat induced by acetylcholine contraction and the mean percent inhibition caused by $100{\mu}l/ml$ Insamjungchuntang fell to 49.0% in guinea pig induced by histamine contraction and by $100{\mu}l/ml$ Insamjungchuntang fell to 48.6% (p<0.05) in rat induced by histamine contraction. Indomethacin and methylene blue $(10^{-7}\;M)$ did not significantly alter the inhibitory effect of lnsamjungchuntang. Also, I could find the effects of lnsamjungchuntang and Insamjungchuntanggamorphine on the tracheal smooth muscle in guinea pig and rat did not change significantly. These results indicate that Insamjungchuntang can relax histamine and acetylcholine-induced contraction of guinea pig and rat tracheal smooth muscle, and that this inhibition involves sympathetic effects.

  • PDF

A STUDY ON IN VIVO AND IN VITRO AMALGAM CORROSION (아말감의 구강내 부식 및 인공 부식에 관한 연구)

  • Lim, Byong-Mok;Kwon, Hyuk-Choon;Um, Chung-Moon
    • Restorative Dentistry and Endodontics
    • /
    • v.22 no.1
    • /
    • pp.1-33
    • /
    • 1997
  • The objective of this study was to analyze the in vitro and in vivo corrosion products of low and high copper amalgams. The four different types of amalgam alloy used in this study were Fine cut, Caulk spherical, Dispersalloy, and Tytin. After each amalgam alloy and Hg were triturated according to the directions of the manufacturer by means of the mechanical amalgamator(Amalgam mixer. Shinhung Co. Korea), the triturated mass was inserted into a cylindrical metal mold which was 12mm in diameter and 10mm in height. The mass was condensed by 150Kg/cm compressive force. The specimen was removed from the mold and aged at room temperature for about seven days. The standard surface preparation was routinely carried out by emery paper polishing under running water. In vitro amalgam specimens were potentiostatically polarized ten times in a normal saline solution at $37^{\circ}C$(potentiostat : HA-301. Hukuto Denko Corp. Japan). Each specimen was subjected to anodic polarization scan within the potential range -1700mV to+400mV(SCE). After corrosion tests, anodic polarization curves and corrosion potentials were obtained. The amount of component elements dissolved from amalgams into solution was measured three times by ICP AES(Inductive Coupled Plasma Atomic Emission Spectrometry: Plasma 40. Perkim Elmer Co. U.S.A.). The four different types of amalgam were filled in occlusal and buccal class I cavities of four human 3rd molars. After about five years the restorations were carefully removed after tooth extraction to preserve the structural details including the deteriorated margins. The occlusal surface, amalgam-tooth interface and the fractured surface of in vivo amalgam corrosion products were analyzed. In vivo and in vitro amalgam specimens were examined and analyzed metallographically by SEM(Scanning Electron Microscope: JSM 840. Jeol Co. Japan) and EDAX(Energy Dispersive Micro X-ray Analyser: JSM 840. Jeol Co. Japan). 1. The following results are obtained from in vitro corrosion tests. 1) Corrosion potentials of all amalgams became more noble after ten times passing through the in vitro corrosion test compared to first time. 2) After times through the test, released Cu concentration in saline solution was almost equal but highest in Fine cut. Ag and Hg ion concentration was highest in Caulk spherical and Sn was highest in Dispersalloy. 3) Analyses of surface corrosion products in vitro reveal the following results. a)The corroded surface of Caulk spherical has Na-Sn-Cl containing clusters of $5{\mu}m$ needle-like crystals and oval shapes of Sn-Cl phase, polyhedral Sn oxide phase. b)In Fine cut, there appeared to be a large Sn containing phase, surrounded by many Cu-Sn phases of $1{\mu}m$ granular shapes. c)Dispersalloy was covered by a thick reticular layer which contained Zn-Cl phase. d)In Tytin, a very thin, corroded layer had formed with irregularly growing Sn-Cl phases that looked like a stack of plates. 2. The following results are obtained by an analysis of in vivo amalgam corrosion products. 1) Occlusal surfaces of all amalgams were covered by thick amorphous layers containing Ca-P elements which were abraded by occlusal force. 2) In tooth-amalgam interface, Ca-P containing products were examined in all amalgams but were most clearly seen in low copper amalgams. 3) Sn oxide appeared as a polyhedral shape in internal space in Caulk spherical and Fine cut. 4) Apical pyramidal shaped Sn oxide and curved plate-like Sn-Cl phases resulted in Dispersalloy. 5) In Tytin, Sn oxide and Sn hydroxide were not seen but polyhedral Ag-Hg phase crystal appeared in internal space which assumed a ${\beta}_l$ phase.

  • PDF

A Study on Driving Safety Evaluation Criteria of Personal Mobility (퍼스널 모빌리티(Personal Mobility)의 주행안전성 평가지표 연구)

  • Park, Bumjin;Roh, Chang-gyun;Kim, Jisoo
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.17 no.5
    • /
    • pp.1-13
    • /
    • 2018
  • Divers types of Personal Mobility(PM) are appeared on the market after the Segway is introduced. PMs have propagated very rapidly with their ease of use, and accidents related with PM show a sudden increase. Many studies on the PM are performed as its trend, but dring safety of passengers are excluded. In this study, criteria which can be adopted for PM's driving safety evaluation are reviewed. Also result of driving safety evaluation on 3 types of PM(wheel chair, kickboard, scooter(seating/standing) and walking using deducted criteria is given. COG(Center of the gravity) and SM(Stability Metric) are finally selected two criteria among many of them used in other fields. COG indicates how the center of mass deviates from the direction of the gravity. SM is a normalized value of generated force when PM moves as internal force, angular momentum, and ground reaction force. 0 means stop, and negative value means rollover, so it can be used for safety evaluation of PM. Average and standard deviation of measurement are standard of safety on the COG analysis. Wheel chair is the most safe and kickboard is the most unstable on the COG analysis. Wheel chair is also ranked as top safe on the SM analysis. Among two riding types(seating and standing) on the scooter, seating type is evaluated more safer than standing type. It is proposed that more various type of PMs are need to get safety evaluation for drivers and devices themselves together.

Case Study of 4-Bar Linkage KAFO in Person With Poliomyelitis (소아마비에서 4절 연쇄 장하지보조기 사례연구)

  • Kim, Jang-Hwan;Kwon, Oh-Yun;Yi, Chung-Hwi;Cho, Sang-Hyun;Cynn, Heon-Seock;Choi, Heung-Sik
    • Physical Therapy Korea
    • /
    • v.20 no.1
    • /
    • pp.18-27
    • /
    • 2013
  • The purpose of this study was to compare the ring lock type knee-ankle-foot orthosis (KAFO) with newly developed 4-bar linkage KAFO on the gait characteristics of persons with poliomyelitis clinically. This 4-bar linkage is the stance control type KAFO which provide the stability during stance phase and knee flexion during swing phase. Two subjects participated in this study voluntarily. We provided the customized 4-bar linkage KAFO then asked the subjects to walk in level surface and stairs under the two different KAFO conditions. The characteristics of gait in the persons with poliomyelitis were evaluated using a 3D motion analysis system and force plate. Additionally 6 minute walk test for physiological cost index were conducted using pulse oximeter to measure the energy consumption. In the results of this study, the differences of 4-bar linkage KAFO compared with ring lock type KAFO are as follows: (1) Walking speed, stride length, and step length on level increased in subjects, (2) The gait symmetry was improved by generated knee flexion and decreased pelvic external rotation on level and stairs walking, (3) Decreased vertical excursion of center of mass and pelvic elevation during swing phase was decreased on level, (4) Knee extension moment, hip flexion moment, hip and knee internal rotation moment of non-braced limb were decreased on level walking, (5) Walking speed in 6-minute walk test was increased and physiological cost index was decreased. These findings indicate that 4-bar linkage KAFO compared with ring lock type KAFO is effective in enhancing pattern, endurance, and energy consumption in level surface and stairs walking.

An Empirical Study on the Relationship between Role Stress and Personal Creativity: The Mediating Roles of Creative Self-Efficacy and Personal Initiative (역할스트레스와 개인 창의성 간의 관계에 대한 실증연구: 창의적 자아효능감과 자기주도성의 매개역할)

  • Heo, Myung Sook;Cheon, Myun Joong
    • The Journal of Information Systems
    • /
    • v.22 no.2
    • /
    • pp.51-83
    • /
    • 2013
  • Personal creativity is critically important for organizations seeking to survive and thrive in today's highly turbulent business environments. Organizations must effectively identify and mobilize the creative resources of their members. When organizational members perceive a work environment that restricts or fails to encourage individual creative expression, a gap may exist between the level of individual creative potential and the actual amount of individual creativity practiced within the organization. In this situation, this paper will examine the impact of role conflict, role ambiguity, creative self-efficacy, and personal initiative on personal creativity. Creative self-efficacy is the subjective belief in one's personal ability to be creative, that is, a personal assessment of one's own creative potential. A strong internal belief in one's ability to successfully engage in creative behaviors is generally considered an important part of the creative process. Personal Initiative refers to behaviors, mainly directed toward work and organizational issues, that are characterized by the following aspects: self-starting, proactive, and persistent in overcoming barriers. Creativity-related creative self-efficacy and personal initiative are critical components to understand motivation that coordinates the relationship between perception and behavior of individual employees. Based on role theory, researchers have focused on role conflict and role ambiguity as the two key ingredients of role stress. Role ambiguity is defined as an evaluation about the lack of salient information needed to perform a role effectively. Role conflict results from two or more sets of incompatible demands involving work-related issues. Employees are usually pursued work-roles more than one in work-focused organization. Too many work-roles and perceived uncertainties at employee's work can be obstacles to personal creativity. In an analysis of results, while role conflict is not negatively related significantly to creative self-efficacy, role ambiguity is negatively related significantly to creative self-efficacy. While role conflict is significantly related to personal creativity, role ambiguity is negatively related significantly to personal creativity. Creative self-efficacy mediates the relationship among role conflict, role ambiguity, and employee creativity. Personal initiative mediates the relationship between creative self-efficacy and employee creativity. This paper shows that creative self-efficacy and personal initiative are the driving force behind personal creativity. Organizations can get some implications of creative-related role conflict and role ambiguity that employees have experienced. As a result, organizations must not only encourage creativity of employees by greater involvement but also encourage their input towards their-focused own works and tasks. And employees should be developed to pace with the organizational needs and development. Management must enable employees to think of new ideas and practices that promotes personal creativity.

The Study on the Critical Success Factors of the Adoption and Use of the ASP-based ERP Systems (ASP방식의 ERP 도입 및 이용의 핵심성공요인에 관한 연구 : 중소제조업체를 중심으로)

  • Jeong Jung-Sik;Kwon Sun-Dong
    • Journal of Information Technology Applications and Management
    • /
    • v.13 no.3
    • /
    • pp.29-57
    • /
    • 2006
  • Small and medium-sized companies (SMEs) face a number of different kinds of barriers to adopt information technology, including the lack of information, limited financial and technical resources, and absence of the well-trained work force in the realm of information technology. But application service provider (ASP)enables these SMEs to informatize. This paper is focused on studying the cases of the adoption and use of the ASP-based ERP systems that 7 SME shad adopted. The factors that influence the adoption and use of SMEs' ASP-based ERP systems are divided into the user companies that adopted the systems, the systems vendors, and environment. From the viewpoint of the user company, the successful adoption and use of the systems is significantly influenced by the clear motive of adopting the systems, the financial readiness, and the strong intention of CEO for pushing ahead with e-Business. From the systems vendor, it is influenced by the technical expertise of the vendor, the knowledge of the user company, and the experience of the systems development. From the perspective of environment, it is influenced by the push from the players in the value chains. The companies that had adopted the ASP-based ERP systems and that had extended the level of systems use had the benefits through reducing the cost, improving the internal business process, and achieving the learning and growth of the organization.

  • PDF