• Title/Summary/Keyword: Axial skeleton

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Research on hysteretic characteristics of EBIMFCW under different axial compression ratios

  • Li, Sheng-cai;Lin, Qiang
    • Earthquakes and Structures
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    • v.22 no.5
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    • pp.461-473
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    • 2022
  • Energy-saving block and invisible multiribbed frame composite wall (EBIMFCW) is an important shear wall, which is composed of energy-saving blocks, steel bars and concrete. This paper conducted seismic performance tests on six 1/2-scale EBIMFCW specimens, analyzed their failure process under horizontal reciprocating load, and studied the effect of axial compression ratio on the wall's hysteresis curve and skeleton curve, ductility, energy dissipation capacity, stiffness degradation, bearing capacity degradation. A formula for calculating the peak bearing capacity of such walls was proposed. Results showed that the EBIMFCW had experienced a long time deformation from cracking to failure and exhibited signs of failure. The three seismic fortification lines of the energy-saving block, internal multiribbed frame, and outer multiribbed frame sequentially played important roles. With the increase in axial compression ratio, the peak bearing capacity and ductility of the wall increased, whereas the initial stiffness decreased. The change in axial compression ratio had a small effect on the energy dissipation capacity of the wall. In the early stage of loading, the influence of axial compression ratio on wall stiffness and strength degradation was unremarkable. In the later stage of loading, the stiffness and strength degradation of walls with high axial compression ratio were low. The displacement ductility coefficients of the wall under vertical pressure were more than 3.0 indicating that this wall type has good deformation ability. The limit values of elastic displacement angle under weak earthquake and elastic-plastic displacement angle under strong earthquake of the EBIMFCW were1/800 and 1/80, respectively.

GROWTH AND COMPOSITION OF THE OMANI DHOFARI CATTLE 2. DISTRIBUTION OF CARCASS TISSUES

  • Mahgoub, O.;Olvey, F.H.;Jeffrey, D.C.
    • Asian-Australasian Journal of Animal Sciences
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    • v.8 no.6
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    • pp.617-625
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    • 1995
  • Distribution of wholesale carcass cuts and tissues was studied in Omani Dhofari bulls and steers raised under intensive management and slaughtered over a range of 110 to 210 kg body weight. The fore quarter of Dhofari cattle carcasses was heavier than the hind quarter with the chuck being the heaviest cut in the half carcass followed by the round whereas the flank was the lightest cut. Proportions of the fore quarter and its cuts increased whereas that of the hind quarter and its cuts decreased with increasing carcass weight. The fore quarter contained higher proportions of carcass tissues especially intermuscular fat than the hind quarter. The chuck and round contained the highest proportions of lean and bone and the flank the least. There was a general trend of increasing proportions of fat and decreasing proportions of lean and bone in carcass cuts and fore and hind quarters with increasing slaughter weight and age. As % total body fat (TBF), total carcass fat (TCF) increased whereas total non-carcass fat (TNCF) decreased. The largest proportion of TBF was deposited in the intermuscular site. Among the TNCF depots, the kidney and omental contributed the highest proportions whereas the pelvic and channel were the lowest. Proportions of M. rhomboideus and M. splenius increased in the half carcass whereas that of M. semitendinosus decreased as the cattle increased in size. The axial skeleton contributed 47.4-51.1, the fore limb 21.6-22.6 and the hind limb 23.9-26.2% of the total carcass bone. Proportions of axial skeleton increased whereas that of fore and hind limbs decreased with increasing slaughter weight and age. There were no major effects of castration on the distribution of weight of carcass cuts or carcass tissues. Steers had higher total body fat at 160 kg body weight and higher proportions of mesenteric, scrotal, pelvic, kidney and total non-carcass fat at 210 kg weight than bulls. As % of total body fat, steers fad significantly higher kidney and total non-carcass fat. There was little effects of castration on proportions of dimensions of individual muscles or bones.

Experimental investigations of the seismic performance of bridge piers with rounded rectangular cross-sections

  • Shao, Guangqiang;Jiang, Lizhong;Chouw, Nawawi
    • Earthquakes and Structures
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    • v.7 no.4
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    • pp.463-484
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    • 2014
  • Solid piers with a rounded rectangular cross-section are widely used in railway bridges for high-speed trains in China. Compared to highway bridge piers, these railway bridge piers have a larger crosssection and less steel reinforcement. Existing material models cannot accurately predict the seismic behavior of this kind of railway bridge piers. This is because only a few parameters, such as axial load, longitudinal and transverse reinforcement, are taken into account. To enable a better understanding of the seismic behavior of this type of bridge pier, a simultaneous influence of the various parameters, i.e. ratio of height to thickness, axial load to concrete compressive strength ratio and longitudinal to transverse reinforcements, on the failure characteristics, hysteresis, skeleton curves, and displacement ductility were investigated. In total, nine model piers were tested under cyclic loading. The hysteretic response obtained from the experiments is compared with that obtained from numerical studies using existing material models. The experimental data shows that the hysteresis curves have significantly pinched characteristics that are associated with small longitudinal reinforcement ratios. The displacement ductility reduces with an increase in ratio of axial load to concrete compressive strength and longitudinal reinforcement ratio. The experimental results are largely in agreement with the numerical results obtained using Chang-Mander concrete model.

A CASE REPORT OF OSTEOCHONDROMA ON MANDIBULAR CONDYLE (하악골 과두에 발생한 골연골종의 치험례)

  • Kim, Mi-Suk;Lee, Mi-Hyang;Jang, Chang-Soo;Kim, Chul-Hwan
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.18 no.2
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    • pp.298-307
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    • 1996
  • Osteochondroma is a common benign tumor of the axial skeleton, especially the distal metaphysis of the femur and the proximal metaphysis of the tibia, however, is occurred rarely on the facial skeleton. Development of the tumor is most frequently seen in the second or third decades of life. Typically, it arises directly from the cortex of the underlying bone, without any intervening zone of abnormal osseous tissue, and is covered by a cap composed of cartilage undergoing calcification. In case of osteochondroma of the mandibular condyle, its clinical features are occulusal change, facial asymmetry, headache, pain and click on temporomandibular joint, mouth opening limitation, and jaw deviation to involved site. This is a case report of a 13-year old woman who had mouth opening limitation and severe temporomandibular joint pain. We obtained successful results with surgical removal of the osteochondroma on the mandibular condyle.

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Giant osteochondroma of the parapharyngeal space: a case report

  • Kim, Chul-Hwan;Lee, Yoon-Sun
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.39 no.1
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    • pp.35-40
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    • 2013
  • Osteochondroma is a common benign tumor of the axial skeleton, especially in the distal metaphysis of the femur and the proximal metaphysis of the tibia, that can occur on the facial skeleton (albeit rarely). Osteochondroma is differentiated from chondroma, osteochondromatosis and osteoma. Osteochondroma shows an irregular radiopaque lesion and chondromatic area surrounded by the osteoma. When it develops in the long bone, it has a marked tendency to occur at 10 to 20 years of age and ceases with the end of pubertal growth. However, when it develops in the mandibular condyle, it is prevalent in the third decade and continuous to develop. Tumors that develop in the long bone have a predilection for men, but tumors in the mandible have a predilection for women. In osteochondroma of the mandibular condyle, clinical features presented include occlusal changes, facial asymmetry, headaches, pain and joint noise on the temporomandibular joint, mouth opening limitations, and jaw deviation at the involved site. The first choice of treatment for the massive osteochondroma is surgical removal. A 70-year-old female patient with an osteochondroma on her right mandibular condyle visited our clinic. We surgically removed the mass with favorable results. It is presented here along with a review of literature on osteochondroma.

An applied model for steel reinforced concrete columns

  • Lu, Xilin;Zhou, Ying
    • Structural Engineering and Mechanics
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    • v.27 no.6
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    • pp.697-711
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    • 2007
  • Though extensive research has been carried out for the ultimate strength of steel reinforced concrete (SRC) members under static and cyclic load, there was only limited information on the applied analysis models. Modeling of the inelastic response of SRC members can be accomplished by using a microcosmic model. However, generally used microcosmic model, which usually contains a group of parameters, is too complicated to apply in the nonlinear structural computation for large whole buildings. The intent of this paper is to develop an effective modeling approach for the reliable prediction of the inelastic response of SRC columns. Firstly, five SRC columns were tested under cyclic static load and constant axial force. Based on the experimental results, normalized trilinear skeleton curves were then put forward. Theoretical equation of normalizing point (ultimate strength point) was built up according to the load-bearing mechanism of RC columns and verified by the 5 specimens in this test and 14 SRC columns from parallel tests. Since no obvious strength deterioration and pinch effect were observed from the load-displacement curve, hysteresis rule considering only stiffness degradation was proposed through regression analysis. Compared with the experimental results, the applied analysis model is so reasonable to capture the overall cyclic response of SRC columns that it can be easily used in both static and dynamic analysis of the whole SRC structural systems.

OSTEOCHONRDOMA OF THE MANDIBULAR CONDYLE : A CASE REPORT (하악골 과두에 생긴 골연골종의 치험례)

  • Ryu, Dong-Mok;Kim, Hye-Jin;Lee, Sang-Chull;Kim, Yeo-Gab;Lee, Baek-Soo
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.28 no.2
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    • pp.132-135
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    • 2002
  • The osteochondroma, also known as osteocartilaginous exostosis, is one of the most common benign tumors of the axial skeleton. These tumours rarely affect the facial skeleton and a true osteochondroma of the mandibular condyle is a very uncommon entity. The tumors are usually slow growing, and symptoms develop over a long time. The most common presentation of the condylar osteochondroma consists of a changing occlusion, the development of facial asymmetry, and a posterior open bite on the affected side. In this case, we treated an osteochondroma of Lt. mandibular condyle through excision of the lesion via the temporal approach to the temporomandibular joint.

Studies on restoring force model of concrete filled steel tubular laced column to composite box-beam connections

  • Huang, Zhi;Jiang, Li-Zhong;Zhou, Wang-Bao;Chen, Shan
    • Steel and Composite Structures
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    • v.22 no.6
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    • pp.1217-1238
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    • 2016
  • Mega composite structure systems have been widely used in high rise buildings in China. Compared to other structures, this type of composite structure systems has a larger cross-section with less weight. Concrete filled steel tubular (CFST) laced column to box-beam connections are gaining popularity, in particular for the mega composite structure system in high rise buildings. To enable a better understanding of the destruction characteristics and aseismic performance of these connections, three different connection types of specimens including single-limb bracing, cross bracing and diaphragms for core area of connections were tested under low cyclic and reciprocating loading. Hysteresis curves and skeleton curves were obtained from cyclic loading tests under axial loading. Based on these tested curves, a new trilinear hysteretic restoring force model considering rigidity degradation is proposed for CFST laced column to box-beam connections in a mega composite structure system, including a trilinear skeleton model based on calculation, law of stiffness degradation and hysteresis rules. The trilinear hysteretic restoring force model is compared with the experimental results. The experimental data shows that the new hysteretic restoring force model tallies with the test curves well and can be referenced for elastic-plastic seismic analysis of CFST laced column to composite box-beam connection in a mega composite structure system.

Seismic performance of mixed column composed of square CFST column and circular RC column in Chinese archaized buildings

  • Xue, Jianyang;Zhou, Chaofeng;Lin, Jianpeng
    • Steel and Composite Structures
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    • v.29 no.4
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    • pp.451-464
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    • 2018
  • This paper presents some quasi-static tests for 4 mixed columns composed of CFST column and RC column. The seismic performance and failure mode were studied under low-cyclic revised loading. The failure mode was observed under different axial compression ratios. The hysteretic curve and skeleton curve were obtained. The effects of axial compression ratio on yield mechanism, displacement ductility, energy dissipation, stiffness and strength attenuation were analyzed. The results indicate that the failure behavior of CFST-RC mixed column with archaized style is mainly caused by bending failure and accompanied by some shear failure. The axial compression ratio performs a control function on the yielding order of the upper and lower columns. The yielding mechanism has a great influence on the ductility and energy dissipation capacity of specimens. Based on the experiment, finite element analysis was made to further research the seismic performance by ABAQUS software. The variable parameters were stiffness ratio of upper and lower columns, axial compression ratio, yielding strength of steel tube, concrete strength and rebar ratio. The simulation results show that with the increase of stiffness ratio of the upper and lower columns, the bearing capacity and ductility of specimens can correspondingly increase. As the axial compression ratio increases, the ductility of the specimen decreases gradually. The other three parameters both have positive effect on the bearing capacity but have negative effect on the ductility. The results can provide reference for the design and engineering application of mixed column consisted of CFST-RC in Chinese archaized buildings.

Perforated TWCF steel beam-columns: European design alternatives

  • Baldassino, Nadia;Bernardi, Martina;Bernuzzi, Claudio;Simoncelli, Marco
    • Steel and Composite Structures
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    • v.35 no.5
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    • pp.701-715
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    • 2020
  • Steel storage racks are lightweight structures, made of thin-walled cold-formed members, whose behaviour is remarkably influenced by local, distortional and overall buckling phenomena, frequently mutually combined. In addition, the need of an easy and rapid erection and reconfiguration of the skeleton frame usually entails the presence of regular perforations along the length of the vertical elements (uprights). Holes and slots strongly influence their behaviour, whose prediction is however of paramount importance to guarantee an efficient design and a safe use of racks. This paper focuses on the behaviour of isolated uprights subjected to both axial load and bending moments, differing for the cross-section geometry and for the regular perforation systems. According to the European standards for routine design, four alternatives to evaluate the bending moment-axial load resisting domains are shortly discussed and critically compared in terms of member load carrying capacity.