scholarly journals Elastic Simulation of Joints with Particle-Based Fluid

2021 ◽  
Vol 11 (15) ◽  
pp. 6900
Author(s):  
Su-Kyung Sung ◽  
Sang-Won Han ◽  
Byeong-Seok Shin
Keyword(s):  
Principal Stress ◽  
Human Body ◽  
Yield Condition ◽  
Maximum Principal Stress ◽  
Human Motion ◽  
The Difference ◽  
The Moment ◽  
External Forces ◽  
Physical Changes ◽  
Elastic Simulation

Skinning, which is used in skeletal simulations to express the human body, has been weighted between bones to enable muscle-like motions. Weighting is not a form of calculating the pressure and density of muscle fibers in the human body. Therefore, it is not possible to express physical changes when external forces are applied. To express a similar behavior, an animator arbitrarily customizes the weight values. In this study, we apply the kernel and pressure-dependent density variations used in particle-based fluid simulations to skinning simulations. As a result, surface tension and elasticity between particles are applied to muscles, indicating realistic human motion. We also propose a tension yield condition that reflects Tresca’s yield condition, which can be easily approximated using the difference between the maximum and minimum values of the principal stress to simulate the tension limit of the muscle fiber. The density received by particles in the kernel is assumed to be the principal stress. The difference is calculated by approximating the moment of greatest force to the maximum principal stress and the moment of least force to the minimum principal stress. When the density of a particle increases beyond the yield condition, the object is no longer subjected to force. As a result, one can express realistic muscles.

scholarly journals How many implants are needed for mandibular full-arch rehabilitation?

2020 ◽  
Vol 19 ◽  
pp. e209191
Author(s):  
Karina Giovanetti ◽  
Ricardo Armini Caldas ◽  
Paulo Henrique Ferreira Caria
Keyword(s):  
Bone Tissue ◽  
Principal Stress ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Von Mises Stress ◽  
Principal Stresses ◽  
Dimensional Finite Element ◽  
The Difference ◽  
Von Mises ◽  
Three Dimensional Finite Element

Aim: To analyze the stress distribution at the peri-implant bone tissue of mandible in full-arch implant-supported rehabilitation using a different number of implants as support. Methods: Three-dimensional finite element models of full-arch prosthesis with 3, 4 and 5 implants and those respective mandibular bone, screws and structure were built. ANSYS Workbench software was used to analyze the maximum and minimum principal stresses (quantitative analysis) and modified von Mises stress (qualitative analysis) in peri-implant bone tissue after vertical and oblique forces (100N) applied to the structure at the cantilever site (region of the first molars). Results: The peak of tensile stress values were at the bone tissue around to the distal implant in all models. The model with 3 implants presented the maximum principal stress, in the surrounding bone tissue, higher (~14%) than the other models. The difference of maximum principal stress for model with 4 and 5 implants was not relevant (~1%). The first medial implant of the model with 5 implants presented the lower (17%) stress values in bone than model with 3 implants. It was also not different from model with 4 implants. Conclusion: Three regular implants might present a slight higher chance of failure than rehabilitations with four or five implants. The use of four implants showed to be an adequate alternative to the use of classical five implants.

scholarly journals Heating and Cooling Anomaly of a Rotating Body

10.14311/664 ◽  
2005 ◽  
Vol 45 (1) ◽  
Author(s):  
O. Brůha ◽  
T. Brůha
Keyword(s):  
Angular Momentum ◽  
The Body ◽  
Temperature Changes ◽  
Rotating Body ◽  
Heating And Cooling ◽  
Stress Energy ◽  
The Difference ◽  
Velocity Changes ◽  
The Moment ◽  
External Forces

This paper deals with an effect which appears when heating or cooling a rotating body. No external forces acting on the body are supposed. Due to thermal expansion, the moment of inertia of the body varies together with the temperature changes. In agreement with the principle of conservation of angular momentum [1], the angular momentum is constant. This results in angular velocity changes and subsequently in kinetic energy changes. Also the stress energy varies together with the changes in thermal dimension. To satisfy the principle of energy conservation we have to suppose that the changes in kinetic and stress energy are compensated by the changes in internal energy, which is correlated with temperature changes of the body. This means that the rules for the heating or cooling process of a rotating body are not the same as those for a body at rest. This idea, applied to a cylinder rotating around its geometric axis under specific parameters, has been mathematically treated. As a result, the difference between the final temperature of the rotating cylinder and the temperature of the cylinder at rest has been found. 

The Art of Drawing Distinctions

2019 ◽  
pp. 407-433
Author(s):  
Alexander Kluge
Keyword(s):  
Nineteenth Century ◽  
Human Body ◽  
Cerebral Hemispheres ◽  
Human Being ◽  
The Will ◽  
The Difference ◽  
Alexander Kluge ◽  
The Moment ◽  
The Mind

This chapter highlights the individual's capacity for differentiation. Imagine the human body: take, for example, the mouth, whose capacity for differentiation would be called a sensation. The largest organ, the skin, also has sensation. The ear: therein lies musicality, the sense of balance, the sense of hearing, and rhythm. These sensations are divided between two cerebral hemispheres. All of these sensations play a role in an encounter with another person. The moment when related sensations reach a decision about another human being is called feeling. This is not something sentimental, but rather is subject to the sentimentalization and commercialization of the nineteenth century. In reality, feeling is something very human. It is what a person adds to an objective relation. In order to be able to convey more clearly the difference between sensation and feeling, Alexander Kluge introduces another term: passion. There is the passion of the mind and there is the mind of passion. This is the intensification of the will, feeling, the sum of various feelings pointed in a single direction.

scholarly journals Acceleration Feature Extraction of Human Body Based on Wearable Devices

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 924
Author(s):  
Zhenzhen Huang ◽  
Qiang Niu ◽  
Ilsun You ◽  
Giovanni Pau
Keyword(s):  
Genetic Algorithm ◽  
Feature Extraction ◽  
Kalman Filter ◽  
Human Body ◽  
Wearable Devices ◽  
Human Motion ◽  
Data Set ◽  
Feature Extraction Method ◽  
Motion Data ◽  
Kalman Filter Algorithm

Wearable devices used for human body monitoring has broad applications in smart home, sports, security and other fields. Wearable devices provide an extremely convenient way to collect a large amount of human motion data. In this paper, the human body acceleration feature extraction method based on wearable devices is studied. Firstly, Butterworth filter is used to filter the data. Then, in order to ensure the extracted feature value more accurately, it is necessary to remove the abnormal data in the source. This paper combines Kalman filter algorithm with a genetic algorithm and use the genetic algorithm to code the parameters of the Kalman filter algorithm. We use Standard Deviation (SD), Interval of Peaks (IoP) and Difference between Adjacent Peaks and Troughs (DAPT) to analyze seven kinds of acceleration. At last, SisFall data set, which is a globally available data set for study and experiments, is used for experiments to verify the effectiveness of our method. Based on simulation results, we can conclude that our method can distinguish different activity clearly.

scholarly journals Loading Effect of Prosthetic Feet’s Anthropomorphicity on Transtibial Osseointegrated Implant

2021 ◽  
Vol 186 (Supplement_1) ◽  
pp. 681-687
Author(s):  
Mark Pitkin ◽  
Laurent Frossard
Keyword(s):  
Free Flow ◽  
Convex Shape ◽  
Bone Implant ◽  
Concave Shape ◽  
Early Loosening ◽  
Osseointegrated Implants ◽  
Osseointegrated Implant ◽  
Quantitative Characteristics ◽  
The Difference ◽  
The Moment

ABSTRACT Introduction Osseointegrated implants for direct skeletal attachment of transtibial prosthesis carry risks that are yet to be fully resolved, such as early loosening, mechanical failure of percutaneous and medullar parts of implant, periprosthetic issues, and infections. Underloading could lead to early loosening and infection. Overloading might compromise the bone–implant interface. Therefore, Goldilocks loading regimen applied by transtibial bone-anchored prostheses is critical for safe and efficient development of osseointegration around the implant during rehabilitation and beyond. We hypothesized that Goldilocks loading could be achieved when ambulating with a so-called anthropomorphic prosthetic ankle showing moment–angle relationship similar to a sound ankle. Materials and Methods Quantitative characteristics of the moment–angle curve of the sound ankle during dorsiflexion phase of a free-pace walking were extracted for 4 able-bodied participants (experiment 1). A slope of the moment–angle curve (stiffness) was calculated twice: for the first half and for the second half of the moment–angle curve. The difference of stiffnesses (those at the second half minus at the first half) was called the index of anthropomorphicity (IA). By definition, positive IA is associated with concave shape of the moment–angle curve, and the negative IA is associated with convex shape. In experiment 2, the same recordings and calculations were performed for 3 participants fitted with transtibial osseointegrated fixation during walking with their usual feet and the Free-Flow Foot (Ohio Willow Wood). The Free-Flow Foot was selected for its anthropomorphicity demonstrated in the previous studies with amputees using traditional socket attachment. Results The IA was 5.88 ± 0.93 for the able-bodied participants, indicating that the stiffness during the first part of the dorsiflexion phase was substantially fewer than during the second parts, as the calf muscles resisted to angulation in ankle substantially less than during the second part of dorsiflexion phase. For amputees fitted with Free-Flow Foot, IA was 2.68 ± 1.09 and −2.97 ± 2.37 for the same amputees fitted with their usual feet. Conclusions Indexes of anthropomorphicity, while of different magnitude, were positive in control able-bodied group and in the amputee group wearing Free-Flow Foot, which was qualitatively associated with concave shape of their moment–angle curves. The 3 usual feet worn by the participants were classified as nonanthropomorphic as their individual moment–angle curves were convex and the corresponding IAs were negative. Furthermore, this study showed that a foot with anthropomorphic characteristics tends to decrease maximal loads at the bone–implant interface as compared to the nonanthropomorphic feet and possibly may minimize the risks to compromise the integrity of this interface.

FEM Stress Analysis and Strength of Scarf Adhesive Joints of Similar Adherend Subjected to Impact Tensile Loadings

2007 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Yuya Hirayama ◽  
He Dan
Keyword(s):  
Young’S Modulus ◽  
Principal Stress ◽  
Stress Wave ◽  
Young's Modulus ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Adhesive Joints ◽  
Stress Wave Propagation ◽  
Adhesive Thickness ◽  
Three Dimensional Finite Element

The stress wave propagation and stress distribution in scarf adhesive joints have been analyzed using three-dimensional finite element method (FEM). The FEM code employed was LS-DYNA. An impact tensile loading was applied to the joint by dropping a weight. The effect of the scarf angle, Young’s modulus of the adhesive and adhesive thickness on the stress wave propagations and stress distributions at the interfaces have been examined. As the results, it was found that the point where the maximum principal stress becomes maximum changes between 52 degree and 60 degree under impact tensile loadings. The maximum value of the maximum principal stress increases as scarf angle decreases, Young’s modulus of the adhesive increases and adhesive thickness increases. In addition, Experiments to measure the strains and joint strengths were compared with the calculated results. The calculated results were in fairly good agreements with the experimental results.

Influence of Slope Gradient on Distribution Rule of Geostress Field in River Valleys

2013 ◽  
Vol 404 ◽  
pp. 365-370 ◽  
Author(s):  
Qi Tao Pei ◽  
Hai Bo Li ◽  
Ya Qun Liu ◽  
Jun Gang Jiang
Keyword(s):  
Numerical Simulation ◽  
Stress Concentration ◽  
Principal Stress ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Slope Gradient ◽  
Bank Slope ◽  
Distribution Rule ◽  
River Valleys ◽  
Gradient Change

During the construction of hydropower station, the change of slope gradient in river valleys often takes place. In order to study influence of slope gradient change on distribution rule of geostress field, the three dimensional unloading models under different slope gradients were established by finite difference software (FLAC3D). After numerical simulation, the results were as follows: (1) The phenomenon of stress concentration at the bottom of river valleys was obvious, which appeared the typical stress fold. Both the depth of stress concentration zone and the principal stress values significantly increased with the increment of slope gradient. (2) Maximum principal stress values increased less in shallow part of upper bank slope (low stress zone) but increased more in the nearby slope foot with the increment of slope gradient, causing great difference in geostress field of bank slope. (3) There was some difference in released energy of bank slope due to slope gradient change in river valleys. In order to distinguish the difference, stress relief zone was further divided into stress stably released zone and stress instability released zone. Finally, take Ada dam area of the western route project of South-to-North Water Transfer as an example, the results by numerical simulation were reliable through comparing the distribution rule of geostress field for the dam, which could provide important reference for stability of the design and construction of steep and narrow river valleys.

Video-Based Human Motion Analysis

2011 ◽  
Vol 403-408 ◽  
pp. 2593-2597
Author(s):  
Hong Bao ◽  
Zhi Min Liu
Keyword(s):  
Motion Analysis ◽  
Human Body ◽  
Body Shape ◽  
Human Motion ◽  
Random Motion ◽  
Human Motion Analysis ◽  
Mass Center ◽  
Shape Features ◽  
Skeleton Model ◽  
Regular Motion

In the analysis of human motion, movement was divided into regular motion (such as walking and running) and random motion (such as falling down).Human skeleton model is used in this paper to do the video-based analysis. Key joints on human body were chosen to be traced instead of tracking the entire human body. Shape features like mass center trajectory were used to describe the movement, and to classify human motion. desired results achieved.

Open access to scientific information: comparative study in DOAJ

2014 ◽  
Vol 35 (4/5) ◽  
pp. 364-374 ◽  
Author(s):  
Tereza Stoyanova Trencheva ◽  
Tania Yordanova Todorova
Keyword(s):  
Open Access ◽  
Comparative Study ◽  
Scientific Information ◽  
Comparative Approach ◽  
Content Type ◽  
Open Access Journals ◽  
Global Movement ◽  
The Difference ◽  
Important Position ◽  
The Moment

Purpose – The purpose of the paper is to provide a comparative retrospective analysis of Bulgarian, Turkish and Croatian Open Access (OA) journals added in Directory of Open Access journals (DOAJ) in the period 2002-2013. Design/methodology/approach – First of all, the study is focussed on brief review of definitions and descriptions of the OA as a global movement. In the study were analyzed the three main OA initiatives and was shown the difference between Golden Road and Green Road. Second of all, the authors used the comparative approach and made a comparative study of the OA journals in Bulgaria, Turkey and Croatia and present the evaluation results and findings. Findings – Qualitative and quantitative data for the study are collected by the DOAJ. The data are analyzed in terms of quantity and period, and the results are presented graphically and tabular and finally there are made major specific conclusions and recommendations. Originality/value – The paper shows that OA in the digital space has an important position in scientific research. There are many discussion issues related to the problems of OA, but overall study of OA to scientific information, and in particular comparative study of Bulgarian, Turkish and Croatian journals in the DOAJ does not exist at the moment.

scholarly journals Against Declarativity

2020 ◽  
pp. 103-117
Author(s):  
Hans Kellner
Keyword(s):  
Literary Form ◽  
Literary Realism ◽  
Declarative Sentence ◽  
Romantic Literature ◽  
Realist Novel ◽  
Historical Discourse ◽  
The World ◽  
The Difference ◽  
The Moment ◽  
Declarative Statement

Historical discourse is a period phenomenon shaped by the rhetorical and genre understanding of the moment in which it became formalized and professionalized - that is, the second half of the nineteenth century. In the figurative arts, realist painting and its rival, photography, was dominant, and the literary form this notion of consciousness took was the realist novel. Literary realism devices replaced romantic literature devices, just as those latter devices had succeeded, but never replaced the eighteenth-century devices. Historical discourse and the very notion of proper history followed realism devices, mostly the single-lens photographic perspective, one viewer’s viewpoint. From a discourse perspective, this approach took the form of declarative, statement-making. Also, it is not to say that the declarative sentence which gives this term its name was rejected as the preferred way of making assertions about the world - far from it. Although a few self-conscious stylists (Derrida, for instance) work hard to avoid it, the declarative sentence is almost inevitable. Their readers work even harder. But just as narrativity encompasses a realm that extends far beyond narratives, so that narratives can proliferate in an environment that has, in a crucial sense, rejected grand narratives, so declarative statements will exist without entailing statement-making. The declarative act became the defining mark of professional history and remained its principal mode, just as it remains the predominant mode of literature and any number of other discourses. Indeed, this essay is written in the declarative rhetorical mode. However, literary modernism, philosophy, and a host of scientific developments have left this way of representing the world behind. Moreover, the same technological and intellectual changes that caused the modernist vision have, at the same time, created a different world to be depicted, a different sort of event to be represented historically. Not only the form but also the content have changed. The ethical and practical frustrations of representing such events have led to a theoretical challenge to the declarative form of knowing and to a challenge for the genre distinctions that constitute guild history: the idea of the past produced by academically professionalized individuals. For example, the difference between history and fiction - or rather, their respective relationship to truth and reality - has blurred. In contrast, history has adopted some of the modernist literature devices and the present’s practical demands.

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