scholarly journals Modular hemipelvic endoprosthesis with a sacral hook: a finite element study

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Bo Wang ◽  
Peidong Sun ◽  
Hao Yao ◽  
Jian Tu ◽  
Xianbiao Xie ◽  
...  
Keyword(s):  
Aseptic Loosening ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Biomechanical Properties ◽  
Stress Distributions ◽  
Three Dimensional Model ◽  
Connection Component ◽  
Static Conditions ◽  
Distribution Of Stress

Abstract Background A novel hemipelvic endoprosthesis with a sacral hook was introduced previously, and its clinical outcome with midterm follow-up showed decreased prosthesis-related complications, especially decreased rate of aseptic loosening. The aim of present study was to evaluate the role of a sacral hook in prosthesis stability and the biomechanical properties of this hemipelvic endoprosthesis. Methods A three-dimensional model of the postoperative pelvis was developed using computed tomography (CT) images. A force of 500 N was applied, and the distribution of stress and displacement was evaluated. Comparisons were performed to explore the role of the sacral hook in prosthesis stability. Prosthesis improvement was simulated to reduce unexpected breakage of the pubic connection plate. Results In the reconstructed hemipelvis, stress distributions were concentrated on the superior area of the acetabulum, sacral connection component, and sacral hook. A maximum stress of 250 MPa was observed at the root of the sacral connection component. The sacral hook reduced the maximum stress and displacement by 14.1% and 32.5%, respectively, when the prosthesis was well fixed and by 10.0% and 42.1%, respectively, when aseptic loosening occurred. Increasing the thickness of the pubic connection plate from 2 to 3.5 mm reduced the maximum stress by 32.0% and 15.8%, respectively. Conclusion A hemipelvic endoprosthesis with a sacral hook fulfills the biomechanical demands of the hemipelvis and is safe under static conditions. The sacral hook is important for prosthesis stability. Increasing the thickness of the pubic connection plate can reduce the maximum stress and risk of fatigue breakage.

The Role of Binary and Ion Nucleation of Sulfuric Acid and Water Vapor in the Dynamics of Sulfate Aerosol Formation in the Atmosphere

2021 ◽  
pp. 53-60
Author(s):  
A. E. Aloyan ◽  
◽  
A. N. Yermakov ◽  
V. O. Arutyunyan ◽  
◽  
...  
Keyword(s):  
Water Vapor ◽  
Sulfuric Acid ◽  
Three Dimensional ◽  
Ionization Rate ◽  
Sulfate Aerosol ◽  
Aerosol Formation ◽  
Three Dimensional Model ◽  
Aerosol Composition ◽  
Transport And Transformation

The results of one-dimensional calculations of the height profiles of nucleated sulfate aerosol particles for the northern mid-latitudes and tropics in winter are presented. Numerical calculations were performed using a three-dimensional model of the transport and transformation of multicompo- nent gas and aerosol substances in the atmosphere, incorporating photochemistry, nucleation involving neutral molecules and ions, as well as condensation/evaporation and coagulation. It is found that the resulting dynamics of the formation of aerosol particle nuclei is not a simple sum of ion and binary (water vapor/sulfuric acid) nucleation rates. This dynamics is determined by the ratio of critical radii of nucleated particles due to binary and ion nucleation of these substances (rcr_bin and rcr_ion) depending on temperature, relative humidity, and ionization rate. This should be taken into account in modeling the gas and aerosol composition of the atmosphere and comparing calculated and observed data.

A Fast Three-Dimensional Model for Strip Rolling

2016 ◽  
Vol 716 ◽  
pp. 566-578 ◽  
Author(s):  
Christian Overhagen ◽  
Paul Josef Mauk
Keyword(s):  
Finite Element ◽  
Stress Gradient ◽  
Three Dimensional ◽  
Significant Loss ◽  
Three Dimensions ◽  
Beam Model ◽  
Stress Distributions ◽  
Three Dimensional Model ◽  
Strip Rolling ◽  
Lateral Direction

Rolling Models have come a long way from the first empirical relations about forward slip and bite conditions to their current state, which allows local quantities to be calculated in two and three dimensions. In this paper, state-of-the-art of analytical modelling of the rolling process is shown with a fully three-dimensional rolling model for hot and cold strip rolling with stress distributions in the longitudinal, vertical and lateral directions. For this purpose, von Karman’s strip approach is extended to account for the stress gradient in lateral direction, as was already shown in different papers. The stress gradient in the vertical (through-thickness) direction is introduced by a modern implementation of Orowan’s inhomogeneous deformation theory. The local stress distributions are compared to results from Finite-Element Calculations obtained with modern FEM codes. It will be shown, under which circumstances expensive FEM calculations can be replaced by simpler models like the one proposed here, which are more time and cost-effective without a significant loss in result precision. The rolling model is extended with a Finite Element Beam Model for work and backup roll deformation, as well as local work roll flattening and thermal crown for hot rolling. The Effects of those features on stress distribution and exit strip profile are shown for hot and cold rolling.

scholarly journals The role of a mid-air collision in drifting snow

2018 ◽  
Author(s):  
Shuming Jia ◽  
Zhengshi Wang ◽  
Shumin Li
Keyword(s):  
Friction Velocity ◽  
Global Climate ◽  
Three Dimensional ◽  
Particle Collision ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Two Phase ◽  
Drifting Snow ◽  
Collision Mechanism

Abstract. Drifting snow, a common two-phase flow movement in high and cold areas, contributes greatly to the mass and energy balance of glacier and ice sheets and further affects the global climate system. Mid-air collisions occur frequently in high-concentration snow flows; however, this mechanism is rarely considered in current models of drifting snow. In this work, a three-dimensional model of drifting snow with consideration of inter-particle collisions is established; this model enables the investigation of the role of a mid-air collision mechanism in openly drifting snow. It is found that the particle collision frequency increases with the particle concentration and friction velocity, and the blown snow with a mid-air collision effect produces more realistic transport fluxes since inter-particle collision can enhance the particle activity under the same condition. However, the snow saltation mass flux basically shows a cubic dependency with friction velocity, which distinguishes it from the quadratic dependence of blown sand movement. Moreover, the snow saltation flux is found to be largely sensitive to the particle size distribution since the suspension snow may restrain the saltation movement. This research could improve our understanding of the role of the mid-air collision mechanism in natural drifting snow.

Dynamics Analyses of Rigid-Flexible Coupling of Spot-Welding Robot

2020 ◽  
Vol 19 (04) ◽  
pp. 855-867
Author(s):  
Xiangru Wang ◽  
Wei Song ◽  
Tao Xue ◽  
He Tian
Keyword(s):  
Industrial Production ◽  
Spot Welding ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Welding Robot ◽  
Three Dimensional Model ◽  
Production Lines ◽  
Flexible Coupling ◽  
Simulation Functions ◽  
Dynamics Analyses

With the development of electronics, mechanical automation, computer and other related disciplines, and the improvement of product efficiency and quality in modern industry, welding robots are born and play an increasingly important role in industrial production lines. 6R welding robot is most commonly used in industrial production lines, so the research on 6R welding robot has practical application values. In this paper, MS165 Yaskawa robot is selected as the target robot. SolidWorks software is used to establish the three-dimensional model of Yaskawa robot, which is imported into Adams. Dynamics analyses of the rigid–flexible coupling system of 6R spot welding robot are studied by powerful dynamic simulation functions of Adams. The maximum stress position of the spot-welding robot working under load is also studied, and the maximum stress curve is obtained.

Three-Dimensional Stress State Around Corrosive Cavities on Pressure Vessels

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Z. Abdulaliyev ◽  
S. Ataoglu ◽  
O. Bulut ◽  
E. S. Kayali
Keyword(s):  
Maximum Stress ◽  
High Stress ◽  
Three Dimensional ◽  
Pressure Vessels ◽  
Empirical Expression ◽  
Ellipsoidal Cavity ◽  
Industrial Sectors ◽  
Internal Surfaces ◽  
Different Types ◽  
Distribution Of Stress

Internal surfaces of pressure vessels used in many industrial sectors are subjected to corrosive effects leading to cavities. In this study, corrosive cavities on investigated pressure vessels are classified according to their shapes and dimensions. Distribution of stress was experimentally investigated around regions of different types of cavities using three-dimensional photoelastic models. An empirical expression is proposed to determine where maximum stress occurs in type of ellipsoidal cavity in the case of uniaxial loading. The obtained results show quite high stress levels around the cavity regions in pressure vessels, which increase the risk of crack formation.

scholarly journals Substrate (aglycone) specificity of human cytosolic beta-glucosidase

2003 ◽  
Vol 373 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Jean-Guy BERRIN ◽  
Mirjam CZJZEK ◽  
Paul A. KROON ◽  
W. Russell MCLAUCHLAN ◽  
Antoine PUIGSERVER ◽  
...  
Keyword(s):  
Structural Model ◽  
Homology Modelling ◽  
Three Dimensional ◽  
Amino Acid Residues ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Mutant Proteins ◽  
Metabolizing Enzyme ◽  
Beta Glucosidase

Human cytosolic β-glucosidase (hCBG) is a xenobiotic-metabolizing enzyme that hydrolyses certain flavonoid glucosides, with specificity depending on the aglycone moiety, the type of sugar and the linkage between them. Based upon the X-ray structure of Zea mays β-glucosidase, we generated a three-dimensional model of hCBG by homology modelling. The enzyme exhibited the (β/α)8-barrel fold characteristic of family 1 β-glucosidases, with structural differences being confined mainly to loop regions. Based on the substrate specificity of the human enzymes, sequence alignment of family 1 enzymes and analysis of the hCBG structural model, we selected and mutated putative substrate (aglycone) binding site residues. Four single mutants (Val168→Tyr, Phe225→Ser, Tyr308→Ala and Tyr308→Phe) were expressed in Pichia pastoris, purified and characterized. All mutant proteins showed a decrease in activity towards a broad range of substrates. The Val168→Tyr mutation did not affect Km on p-nitrophenyl (pNP)-glycosides, but increased Km 5-fold on flavonoid glucosides, providing the first biochemical evidence supporting a role for this residue in aglycone-binding of the substrate, a finding consistent with our three-dimensional model. The Phe225→Ser and Tyr308→Ala mutations, and, to a lesser degree, the Tyr308→Phe mutation, resulted in a drastic decrease in specific activities towards all substrates tested, indicating an important role of those residues in catalysis. Taken together with the three-dimensional model, these mutation studies identified the amino-acid residues in the aglycone-binding subsite of hCBG that are essential for flavonoid glucoside binding and catalysis.

scholarly journals Make-Belief in Language and Verity of Legitimized Oppression: A Critical Analysis of Selected Extracts From Anita Shreve's Body Surfing

2018 ◽  
Vol III (I) ◽  
pp. 298-324
Author(s):  
Abdul Waheed Qureshi ◽  
Rab Nawaz Khan
Keyword(s):  
Critical Discourse Analysis ◽  
Meaning Making ◽  
Three Dimensional ◽  
Critical Discourse ◽  
The Novel ◽  
Three Dimensional Model ◽  
Dominant Ideology ◽  
Truth Claim ◽  
Opposite Gender

The research in hand is a textual analysis of the novel Body Surfing by Anita Shreve which explains the role of language in the construction of an ideology as reality. The aim is to highlight the construction of a certain concept or ideology as a dominant truth claim in society through discourse and how is it blindly followed by all the members without the least strife to change that socalled dominant ideology. Language as a major agent in the construction and perpetuation of an ideology is forever the discourse of those who are in power. This research will propound the discourse active behind the verity of 'oppression' done to women as taken-for-granted and fair. By employing Critical Discourse Analysis (CDA) as research method, the study will critically examine the role of language in legalizing women oppression. We have cultivated the idea of 'women as weak' into something real, that has come to us generation after generation, through language. This supposition provides theoretical underpinnings for the research, which is arrived at through CDA by treating language post-structurally. The literature analyzed highlights the role of language in the process of meaning-making by considering it to convey reality. The various words and phrases from the extracts in hand with contextual and conceptual affiliation, are dealt with under the backdrop of Fairclough's (1992) Three Dimensional Model of CDA, which results in the recognition of oppression thought as legitimate by the ultimate use of language. The analysis done under the backdrop of poststructuralism will show that language is not the depiction of maximum reality rather; it is we, the users of language, who make it real by considering some concepts as truth and others as myth. The paper concludes that the opposite gender is actually oppressed and that this oppression is not given, rather the constructed one. CDA challenges this oppression and declares it the work of language only. It (language) has no signs of reality, subsistence or truth.

Effect of Range of Stress on Fatigue of 76S-T61 Aluminum Alloy Under Combined Stresses Which Produce Yielding

1953 ◽  
Vol 20 (3) ◽  
pp. 365-374
Author(s):  
W. N. Findley
Keyword(s):  
Test Data ◽  
Maximum Stress ◽  
Crack Formation ◽  
Static Tests ◽  
Combined Stresses ◽  
The Mean ◽  
Distribution Of Stress ◽  
Nonlinear Distribution ◽  
Mean Stresses

Abstract Fatigue test data under bending, torsion, and combined bending and torsion are presented for mean stresses from zero to values which cause substantial yielding. The mean nominal stresses in the bending and the torsion tests were corrected for the effect of the nonlinear distribution of stress resulting from yielding. Static tests in tension, compression, bending, and torsion also are described. The applicability of several theories of failure are compared with these test data. The role of anisotropy of the material, mechanism of crack formation, mean stress, and maximum stress are discussed.

Media and Religious Tourism

2021 ◽  
pp. 210-231
Author(s):  
Rizwan Shabbir ◽  
Aysha Batool
Keyword(s):  
Thematic Analysis ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Tourist Behavior ◽  
Visitor Management ◽  
Religious Tourism ◽  
The Subject ◽  
Socio Economic Impact ◽  
Research Domains

This chapter aims at presenting a thematic analysis of 64 research articles on religious tourism published from 2009 to 2020 by adopting a systematic literature review method. The results indicate that prominent topics discussed were amplification of concepts, tourist motivations, and experience. The evolution of religious tourism concept through nexus of diverse scholarly terms, related domains, and religious practices needs a comprehensive literary debate to refine the subject. The socio-economic impact of religious tourism also calls for the enrichment of topics on scholarly and practical grounds. Issues such as host and tourist behavior, social interaction, visitor management, marketing components, and the role of media need to be explored for the progression of religious tourism in line with sustainability. The chapter contributes to the literature by proposing a three-dimensional model focusing on the role of media and potential research domains for further exploration.

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