An Equivalent 3-D Method for Analyzing Orthogonally Stiffened Plate Structures

1987 ◽  
Vol 31 (02) ◽  
pp. 101-106
Author(s):  
Kyu Nam Cho ◽  
William S. Vorus
Keyword(s):  
Bridge Decks ◽  
Three Dimensional ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Work Related ◽  
Beam Elements ◽  
Proposed Model ◽  
The Relationship

A new three-dimensional method is proposed for analyzing orthogonally stiffened grillage structures. The method is based on earlier work related to bridge decks. The relationship between system displacement and loads is described mathematically, and matrices are developed to examine the shear compatibility between plate and beam elements. The paper concludes with a comparison between deflections obtained by several different procedures and the proposed model.

scholarly journals Steering Algorithm for a Flexible Microrobot to Enhance Guidewire Control in a Coronary Angioplasty Application

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 617 ◽  
Author(s):  
Ali Kafash Hoshiar ◽  
Sungwoong Jeon ◽  
Kangho Kim ◽  
Seungmin Lee ◽  
Jin-young Kim ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Three Dimensional ◽  
Coronary Intervention ◽  
Molding Method ◽  
Proposed Model ◽  
Percutaneous Coronary ◽  
Identification Approach ◽  
The Right ◽  
The Relationship

Magnetically driven microrobots have been widely studied for various biomedical applications in the past decade. An important application of these biomedical microrobots is heart disease treatment. In intravascular treatments, a particular challenge is the submillimeter-sized guidewire steering; this requires a new microrobotic approach. In this study, a flexible microrobot was fabricated by the replica molding method, which consists of three parts: (1) a flexible polydimethylsiloxane (PDMS) body, (2) two permanent magnets, and (3) a micro-spring connector. A mathematical model was developed to describe the relationship between the magnetic field and the deformation. A system identification approach and an algorithm were proposed for steering. The microrobot was fabricated, and the models for steering were experimentally validated under a magnetic field intensity of 15 mT. Limitations to control were identified, and the microrobot was steered in an arbitrary path using the proposed model. Furthermore, the flexible microrobot was steered using the guidewire within a three-dimensional (3D) transparent phantom of the right coronary artery filled with water, to show the potential application in a realistic environment. The flexible microrobot presented here showed promising results for enhancing guidewire steering in percutaneous coronary intervention (PCI).

scholarly journals A Modeling Framework: To Analyze the Relationship between Accessibility, Land Use and Densities in Urban Areas

2021 ◽  
Vol 13 (2) ◽  
pp. 467
Author(s):  
Amila Jayasinghe ◽  
N. B. S. Madusanka ◽  
Chethika Abenayake ◽  
P. K. S. Mahanama
Keyword(s):  
Land Use ◽  
Land Use Planning ◽  
Urban Areas ◽  
Three Dimensional ◽  
Limited Attention ◽  
Modeling Framework ◽  
Transport Planning ◽  
Proposed Model ◽  
The Impact ◽  
The Relationship

The study proposes a framework to model the three-dimensional relationship among density, land use, and accessibility in urban areas constructively contributing to overcome the limitations noted in the domains of urban planning and transport planning. First, most of the existing studies have focused on the topological characteristics in capturing the accessibility, but a limited attention has been given on measuring the accessibility by considering both topological and roadway characteristics. Second, the existing research studies have acknowledged the relationship among density, land use, and accessibility while a limited attention has been given to develop a modeling framework to capture the three-dimensional relationship. The modelling framework was tested in three urban areas in Sri Lanka. The research first analyzed the three-dimensional link among density, land use, and accessibility in the case studies. Then, the study developed a set of regression models to capture the density from the land use and accesability. The proposed model recorded a satisfactory level of accuracy (i.e., R2 > 0.70) on a par with internationally accepted standards. The relationship was further elaborated through a decision tree analysis and 4D plot diagrams. Findings of the study can be utilized to model the density of a given land use and the correspondent accessibility scenarios. The proposed model is capable of quantifying the impact of the changes in the density correspondent to the accessibility and land use. Therefore, the study concludes that this will be an effective tool for decision-makers in the fields of land-use planning and transport planning for scenario building, impact analysis, and the formulation of land use zoning and urban development plans aiming at the overarching sustainability of future cities.

Dynamic stiffness formulation for the vibrations of stiffened plate structures with consideration of in-plane deformation

2017 ◽  
Vol 24 (20) ◽  
pp. 4825-4838 ◽  
Author(s):  
Xuewen Yin ◽  
Wenwei Wu ◽  
Kuikui Zhong ◽  
Hui Li
Keyword(s):  
Finite Element ◽  
Dynamic Stiffness ◽  
Plane Deformation ◽  
Element Model ◽  
The Finite Element Method ◽  
Plate Structures ◽  
Beam Elements ◽  
Stiffness Model ◽  
Out Of Plane ◽  
The Relationship

A dynamic stiffness method is presented for the vibrations of plate structures that are reinforced by eccentric stiffeners. The model incorporates both out-of-plane and in-plane deformations of the plates and the stiffeners. Based on the relationship between the forces and displacements along the common edges of the plate or beam elements, the dynamic stiffness formulae for the plate and the beam elements are derived, respectively. The globally assembled dynamic stiffness matrix is then obtained using the finite element method so that the dynamics of built-up stiffened plates can be readily addressed by using the present method. Compared to the conventional finite element model, the dynamic stiffness model can provide very accurate solutions using only one element over each uniform plate and beam member, regardless of its geometry.

scholarly journals How Does Irrigation Affect Crop Growth? A Mathematical Modeling Approach

Mathematics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 151
Author(s):  
Vicente Díaz-González ◽  
Alejandro Rojas-Palma ◽  
Marcos Carrasco-Benavides
Keyword(s):  
Plant Growth ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Three Dimensional ◽  
Nonlinear Dynamic System ◽  
Plant Size ◽  
Proposed Model ◽  
Exponentially Stable ◽  
The Relationship

This article presents a qualitative mathematical model to simulate the relationship between supplied water and plant growth. A novel aspect of the construction of this phenomenological model is the consideration of a structure of three phases: (1) The soil water availability, (2) the available water inside the plant for its growth, and (3) the plant size or amount of dry matter. From these phases and their interactions, a model based on a three-dimensional nonlinear dynamic system was proposed. The results obtained showed the existence of a single equilibrium point, global and exponentially stable. Additionally, considering the framework of the perturbation theory, this model was perturbed by incorporating irrigation to the available soil water, obtaining some stability results under different assumptions. Later through the control theory, it was demonstrated that the proposed system was controllable. Finally, a numerical simulation of the proposed model was carried out, to depict the soil water content and plant growth dynamic and its agreement with the results of the mathematical analysis. In addition, a specific calibration for field data from an experiment with wheat was considered, and these parameters were then used to test the proposed model, obtaining an error of about 6% in the soil water content estimation.

EFFECT OF STRESS INTENSITY FACTOR IN EVALUATION OF INSTABILITY OF ATHEROSCLEROTIC PLAQUE

2014 ◽  
Vol 14 (05) ◽  
pp. 1450072 ◽  
Author(s):  
HADI MOHAMMADI ◽  
KIBRET MEQUANINT
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Future Research ◽  
Plaque Morphology ◽  
Fe Model ◽  
Fibrous Cap ◽  
Arterial Blood ◽  
Proposed Model ◽  
Fibrous Cap Thickness ◽  
The Relationship

Understanding the relationship between coronary arterial blood pressure, plaque morphology and composition, and sites of fibrous cap (FC) bursting, has been the focus of many recent studies. Instability of atherosclerotic plaques, defined as the propensity for FCs to burst, has been thought to occur at places where FCs are thin and necrotic core (NC) areas are large and highly compliant. However, here we show quantitatively, using a fiber-reinforced, anisotropic and hyperelastic FE model, that FC thickness and NC size and compliance alone are limited in predicting vulnerable and high-risk plaques. We suggest that plaque instabilities primarily occur at sites of high and concentrated mechanical stresses irrespective of fibrous cap thickness or NC area and compliance. Also, limitations of imaging techniques, such as intravascular ultrasound and optical coherence tomography, for providing input into (FE) models of atherosclerosis are discussed. The proposed model can be used to predict vulnerable plaque sites and rupture risks in patients. The current study also provides a framework for future research in which three-dimensional platform and viscoelastic properties of plaque composition can be considered in time-dependent and fatigue studies.

Development and Construct Validation of the German Workplace Trust Survey (G-WTS)

2010 ◽  
Vol 26 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Nale Lehmann-Willenbrock ◽  
Simone Kauffeld
Keyword(s):  
Convergent Validity ◽  
Affective Commitment ◽  
Discriminant Validity ◽  
Organizational Context ◽  
Organizational Trust ◽  
Three Dimensional ◽  
Future Research ◽  
Work Related ◽  
Reliable Assessment ◽  
Workplace Trust

In research on trust in the organizational context, there is some agreement evolving that trust should be measured with respect to various foci. The Workplace Trust Survey (WTS) by Ferres (2002) provides reliable assessment of coworker, supervisor, and organizational trust. By means of a functionally equivalent translation, we developed a German version of the questionnaire (G-WTS) comprising 21 items. A total of 427 employees were surveyed with the G-WTS and questionnaires concerning several work-related attitudes and behaviors and 92 of these completed the survey twice. The hypothesized three-dimensional conceptualization of organizational trust was confirmed by confirmatory factor analysis. The G-WTS showed good internal consistency and retest reliability values. Concerning convergent validity, all of the three G-WTS dimensions positively predicted job satisfaction. In terms of discriminant validity, Coworker Trust enhanced group cohesion; Supervisor Trust fostered innovative behavior, while Organizational Trust was associated with affective commitment. Theoretical and practical contributions as well as opportunities for future research with the G-WTS are discussed.

The Influence of Cognitive and Affective Reactions to Feedback on Subsequent Goals

2010 ◽  
Vol 15 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Remus Ilies ◽  
Timothy A. Judge ◽  
David T. Wagner
Keyword(s):  
Performance Feedback ◽  
Business School ◽  
Structural Equation ◽  
Emotional Reactions ◽  
Equation Model ◽  
Proposed Model ◽  
And Performance ◽  
Dispositional Measure ◽  
The Relationship ◽  
Reactions To Feedback

This paper focuses on explaining how individuals set goals on multiple performance episodes, in the context of performance feedback comparing their performance on each episode with their respective goal. The proposed model was tested through a longitudinal study of 493 university students’ actual goals and performance on business school exams. Results of a structural equation model supported the proposed conceptual model in which self-efficacy and emotional reactions to feedback mediate the relationship between feedback and subsequent goals. In addition, as expected, participants’ standing on a dispositional measure of behavioral inhibition influenced the strength of their emotional reactions to negative feedback.

YENİDOĞAN YOĞUN BAKIM ÜNİTELERİNDE İŞ KAZALARI RİSKLERİ VE NEDENLERİNE YÖNELİK BİR ARAŞTIRMA

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Haluk Tanrıverdi ◽  
Orhan Akova ◽  
Nurcan Türkoğlu Latifoğlu
Keyword(s):  
Intensive Care ◽  
Intensive Care Units ◽  
Physical Environment ◽  
Neonatal Intensive Care ◽  
Organizational Factors ◽  
Occupational Accidents ◽  
Neonatal Intensive Care Units ◽  
Work Related ◽  
Physical Conditions ◽  
The Relationship

This study aims to demonstrate the relationship between the qualifications of neonatal intensive care units of hospitals (physical conditions, standard applications, employee qualifications and use of personal protective equipment) and work related causes and risks, employee related causes and risks when occupational accidents occur. Accordingly, a survey was prepared and was made among 105 nurses working in 3 public and 3 private hospital's neonatal intensive care units, in the January of 2010. The survey consists of questions about the qualifications of neonatal intensive care units, work related causes and risks, and employee related causes and risks. From the regression analysis conducted, it has been found that confirmed hypotheses in several studies in the literature were not significant in this study. The sub-dimensions in which relationships has been found show that the improvement of the physical environment in workplace, the improvement of the employee qualifications and standard applications can reduce the rate of occupational accidents. According to the results of this study management should take care of the organizational factors besides to improvement of the physical environment in workplace, the improvement of the employee qualifications and standard applications.

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