• Title/Summary/Keyword: Leg press

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Current effects on global motions of a floating platform in waves

  • Shen, Meng;Liu, Yuming
    • Ocean Systems Engineering
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    • v.7 no.2
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    • pp.121-141
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    • 2017
  • The purpose of this paper is to understand and model the slow current (~2 m/s) effects on the global response of a floating offshore platform in waves. A time-domain numerical simulation of full wave-current-body interaction by a quadratic boundary element method (QBEM) is applied to compute the hydrodynamic loads and motions of a floating body under the combined influence of waves and current. The study is performed in the context of linearized potential flow theory that is sufficient in understanding the leading-order current effect on the body motion. The numerical simulations are validated by quantitative comparisons of the hydrodynamic coefficients with the WAMIT prediction for a truncated vertical circular cylinder in the absence of current. It is found from the simulation results that the presence of current leads to a loss of symmetry in flow dynamics for a tension-leg platform (TLP) with symmetric geometry, resulting in the coupling of the heave motion with the surge and pitch motions. Moreover, the presence of current largely affects the wave excitation force and moment as well as the motion of the platform while it has a negligible influence on the added mass and damping coefficients. It is also found that the current effect is strongly correlated with the wavelength but not frequency of the wave field. The global motion of a floating body in the presence of a slow current at relatively small encounter wave frequencies can be satisfactorily approximated by the response of the body in the absence of current at the intrinsic frequency corresponding to the same wavelength as in the presence of current. This finding has a significant implication in the model test of global motions of offshore structures in ocean waves and currents.

Assessment of Isokinetic Muscle Strength in the Knee Extensor Through the Ankle Joint Angles (발목관절 각도에 따른 무릎 폄근의 등속성 근력 평가)

  • Park, Sang-Young;Kim, Chung?Sun;Kim, Joong?Hwi;Lee, In?Hee;Jang, Jong?Sung;Seo, Tae?Soo
    • The Journal of Korean Physical Therapy
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    • v.23 no.1
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    • pp.13-19
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    • 2011
  • Purpose:This study was designed to investigate difference in isokinetic muscle strength in the knee extensor muscle and characteristic differences in muscle strength between males and females through the ankle joint angles. Methods: Seventy-four subjects participated in this study. There were two groups: 36 males and 38 females. The mean age of the men was 24.58 years and women was 23.74 years. Subjects were seated on a CON-TREX LP (leg press) lean to back of chair, and there bodies were fixed by straps with the hip joint at an angle of $130^{\circ}$. After randomly fixing the ankle joint at $0^{\circ}$, $20^{\circ}$, and $40^{\circ}$ of plantar flexion (PF) in range of full extension of knee joint. We studied force max average, force max average/kg, power average, and total work through the angle of the ankle joint when the knee joint was extended from $90^{\circ}$ to $180^{\circ}$. Results: In the male group, all maximum measured value showed at the ankle joint $0^{\circ}$, all minimum measured value showed at $40^{\circ}$ PF (p<0.01). In the female group, all maximum measured value showed at the ankle joint $20^{\circ}$ PF, especially the power average increased significantly. All minimum measured value showed $40^{\circ}$ PF (p<0.01). Conclusion: There are differences between males and females in isokinetic muscle strength of the knee extensor through ankle joint angles in healthy adults. Males and Females have different characteristics of muscle strength through the ankle joint angles.

Structural health rating (SHR)-oriented 3D multi-scale finite element modeling and analysis of Stonecutters Bridge

  • Li, X.F.;Ni, Y.Q.;Wong, K.Y.;Chan, K.W.Y.
    • Smart Structures and Systems
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    • v.15 no.1
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    • pp.99-117
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    • 2015
  • The Stonecutters Bridge (SCB) in Hong Kong is the third-longest cable-stayed bridge in the world with a main span stretching 1,018 m between two 298 m high single-leg tapering composite towers. A Wind and Structural Health Monitoring System (WASHMS) is being implemented on SCB by the Highways Department of The Hong Kong SAR Government, and the SCB-WASHMS is composed of more than 1,300 sensors in 15 types. In order to establish a linkage between structural health monitoring and maintenance management, a Structural Health Rating System (SHRS) with relevant rating tools and indices is devised. On the basis of a 3D space frame finite element model (FEM) of SCB and model updating, this paper presents the development of an SHR-oriented 3D multi-scale FEM for the purpose of load-resistance analysis and damage evaluation in structural element level, including modeling, refinement and validation of the multi-scale FEM. The refined 3D structural segments at deck and towers are established in critical segment positions corresponding to maximum cable forces. The components in the critical segment region are modeled as a full 3D FEM and fitted into the 3D space frame FEM. The boundary conditions between beam and shell elements are performed conforming to equivalent stiffness, effective mass and compatibility of deformation. The 3D multi-scale FEM is verified by the in-situ measured dynamic characteristics and static response. A good agreement between the FEM and measurement results indicates that the 3D multi-scale FEM is precise and efficient for WASHMS and SHRS of SCB. In addition, stress distribution and concentration of the critical segments in the 3D multi-scale FEM under temperature loads, static wind loads and equivalent seismic loads are investigated. Stress concentration elements under equivalent seismic loads exist in the anchor zone in steel/concrete beam and the anchor plate edge in steel anchor box of the towers.

Anti-collapse performance analysis of unequal span steel-concrete composite substructures

  • Meng, Bao;Li, Liangde;Zhong, Weihui;Tan, Zheng;Zheng, Yuhui
    • Steel and Composite Structures
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    • v.39 no.4
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    • pp.383-399
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    • 2021
  • In the study, three 1:3-scale unequal span steel-concrete composite substructures with top-seat angle and double web angle connection were designed and identified as specimens GTSDWA-0.6, GTSDWA-1.0, and GTSDWA-1.4. Pseudo-static tests and refined numerical model analysis were conducted to examine the anti-progressive collapse performance of a semi-rigid steel-concrete composite substructure. The results indicated that the failure modes of the three specimens revealed that the fracture occurred in the root of the long leg of the top/seat angle in tension at the connection. With increases in the span ratio of the left and right composite beams, the bearing capacities of the composite substructures decreased, and the corresponding displacement increased. With respect to GTSDWA-0.6 and GTSDWA-1.4, the resistance due to the short composite beam corresponded to 62% and 60%, respectively, and the total resistance provided by the short composite beam exceeded that of the long composite beam. With respect to GTSDWA-1.0, the resistance due to the left and right composite beams was similar. All three specimens underwent the flexure mechanism and flexure-axial mixed mechanism stages. They resisted the external load mainly via the flexure mechanism. Moreover, the addition of stiffeners on both sides of the top and seat angles is advantageous in terms of improving the collapse resistance and ductility of unequal span composite substructures.

Seismic response study of tower-line system considering bolt slippage under foundation displacement

  • Jia-Xiang Li;Jin-Peng Cheng;Zhuo-Qun Zhang;Chao Zhang
    • Steel and Composite Structures
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    • v.52 no.2
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    • pp.135-143
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    • 2024
  • Once the foundation displacement of the transmission tower occurs, additional stress will be generated on the tower members, which will affect the seismic response of transmission tower-line systems (TTLSs). Furthermore, existing research has shown that the reciprocating slippage of joints needs to be considered in the seismic analysis. The hysteretic behavior of joints is obtained by model tests or numerical simulations, which leads to the low modeling efficiency of TTLSs. Therefore, this paper first utilized numerical simulation and model tests to construct a BP neural network for predicting the skeleton curve of joints, and then a numerical model for a TTLS considering the bolt slippage was established. Then, the seismic response of the TTLS under foundation displacement was studied, and the member stress changes and the failed member distribution of the tower were analyzed. The influence of foundation displacement on the seismic performance were discussed. The results showed that the trained BP neural network could accurately predict the hysteresis performance of joints. The slippage could offset part of the additional stress caused by foundation settlement and reduce the stress of some members when the TTLS with foundation settlement was under earthquakes. The failure members were mainly distributed at the diagonal members of the tower leg adjacent to the foundation settlement and that of the tower body. To accurately analyze the seismic performance of TTLSs, the influence of foundation displacement and the joint effect should be considered, and the BP neural network can be used to improve modeling efficiency.

Effect of Complex Training on Inflammatory Markers and Homocysteine of Obese Men (복합트레이닝이 비만남성의 염증지표와 homocysteine에 미치는 영향)

  • Jin, Chan-Ho;Kwak, Yi-Sub
    • Journal of Life Science
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    • v.25 no.8
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    • pp.932-935
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    • 2015
  • The purpose of this study was the effect of complex training of obese men in their 30s on inflammatory markers and homocysteine, a risk factor for cardiovascular disease. The subjects consisted of obese men (n=12) with the body fat ratio of 25% or above in their mid 30s who had no medical conditions and can follow the exercise routine required by this study. To achieve the purpose of this study measured the maximum oxygen intake (VO2max) and 1RM of 5 kinds of machine(bench press, lat pull down, arm curl, leg press, squat) as a preliminary test; based on the results, performed 8 weeks complex training (aerobic exercise + weight training); and then analyzed the variation in body composition (body weight, body fat and BMI), blood inflammatory markers (IL-6, TNF-α and CRP), and homocysteine between before and after training. The results exhibited that 8 weeks complex training reduced weight, body fat and BMI significantly (p<0.01) and also reduced inflammatory marker CRP and homocysteine, a risk factor for cardiovascular disease, significantly (p<0.05). In conclusion, 8 weeks complex training confirmed the variation in body composition, and this variation has a positive effect on the inflammatory marker and the risk factor for cardiovascular disease.

'Studies on diagnosis and Treatment of tumor.abscess.ulcer in intestinal carbuncle' (장옹(腸癰)에 있어서 종양(腫瘍).농양(膿瘍).궤양(潰瘍)의 진단(診斷)과 치료(治療)에 관(關)한 고찰(考察))

  • Han, Gyu-Eon;Ryu, Bong-Ha;Park, Dong-Won;Ryu, Gi-Won;Jang, In-Gyu
    • The Journal of Internal Korean Medicine
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    • v.11 no.1
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    • pp.93-107
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    • 1990
  • Studies on diagnosis and treatment of tumor . abscess . ulcer in intestinal carbuncle were carried out. The result of studies were summerized as follows: 1. By Nai-Gyung carbuncle-tumor arose from disharmony between nutrient and defensive because of cold, abscess arose from fever victory between cold and fever, ulcer arose from decreasing function of Bi-Kam year. By latter literature Bi-Kam year could be interpreted that spleen stomach was invaded evil influence from unattainable vital force of the earth. 2. Sites of intestinal carbuncle were large intestine, small intestine, intestinal inside or outside between large and small intestine, Intestinal carbuncle was common name of a disease about large intestinal carbuncle, small intestinal carbuncle, pelvic intestinal carbuncle, shrink leg intestinal carbuncle etc.. Pain appeared Chunchu-Hyul in large intestinal carbuncle, and Gwanweon-Hyul in small intestinal carbuncle. 3. On abdominal diagnosis tumor had indistinct pain of Gwanweon Chunchu, edema and heary feeling in low abdomen, no excessive pain by hand press and intestinal boiling sound. In abscess pain descended from right side of low abdomen to huckle, and there was rejection against press, feeling about fever,water sound with flank movement. In ulcer hand approach was difficult since excessive pain diffuse to whole abdomen, and perforating ulcer sometimes caused a serious symptom of umbilical pus. 4. On fecal and urinary diagnosis in tumor urine was yellowish red pollakiuria like gonorrhoea and occasional constipation. In abscess uncomfortable rough pain short red early urine like gonorrhoea appeared during urination, and constipation with stinging pain appeared during defecation. In ulcer red rough pyuria appeared, and stinging and pain with puruloid blood appeared during defecation. 5. On treatment in tumor Daiwhang-Tang Daisenggi-Tang Dangui-Jun by dissipation method, calming down method, interior reliance maturation method, in abscess Mokdan-San Euiiin-Tang Jeokduiin-Tang by the method of water repelling pus discharge, acute breaking, in ulcer Takridanggui-Tang Paljin-Tang Bojungikki-Tang were each used by the method of interior reliance, virulence astriction, supplement vital force and blood, supplement spleen stomach. 6. On treatment patient may have to be careful of excessive moving and suprising anxiety. Abuse of acupuncture and moxibustion made patient worse, misuse of analgesics purgative intestinal irrigation etc. could provoke difficult diagnosis and perforation. So you must treat after exact diagnosis. 7. Prognosis of ease tumor ease abscess ease ulcer and ease astriction was good. If the intestinal carbuncle were not to promote to abscess and ulcer for a long time, its prognosis was bad and it could metastasize to cancer because of dark purple with hardness. So tumor abscess ulcer in intestinal carbuncle may be significant of precancerous lesion.

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The Effect of Kinesio Taping on Muscle Strength Improvement, Blood Fatigue Factors, Muscle Fatigue and Damage Index (Kinesio taping이 근력, 혈중 피로물질 및 근 손상 물질 농도변화에 미치는 영향)

  • Lee, Min-Sun;Paik, Il-Young;Kwak, Yi-Sub;No, Hee-Tae;Jin, Hwa-Eun
    • Journal of Life Science
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    • v.20 no.6
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    • pp.870-876
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    • 2010
  • The purpose of this study was to examine the effect of kinesio taping on muscle strength and changes of muscle fatigue and damage. 10 male subjects participated in 1-RM and isometric cybex muscle strength tests with and without taping application. Muscle strength (bench press, leg press) and extension (knee, shoulder) strength were significantly increased after taping, but there was no significant difference in flexion (knee, shoulder) strength. The concentration of fatigue factors (ammonia, phosphorous), muscle damage index substances (CK, LDH), IGF-I and creatinine were reduced after taping, but there were no significant differences.