scholarly journals Frictional Detachment Between Slender Whisker and Round Obstacle

2020 ◽  
Vol 87 (10) ◽  
Author(s):  
T. J. Wang ◽  
J. F. Nie ◽  
Q. Peng ◽  
X. Liu ◽  
Y. G. Wei
Keyword(s):  
Contact Problem ◽  
Contact Force ◽  
Beam Theory ◽  
Small Deformation ◽  
Comprehensive Understanding ◽  
Rotational Mode ◽  
Motion Modes ◽  
Frictional Dissipation ◽  
Round Obstacle ◽  
The Relationship

Abstract In nature, hair-like whiskers are used to detect surrounding information, such as surface texture and air flow field. The detection requires a comprehensive understanding of the relationship between whisker deformation and the contact force. With a whisker being modeled as a slender beam, the contact problem cannot be solved by small deformation beam theory and thus requires a new mechanical model to build up the relationship between whisker deformation and the contact force. In this work, the contact problem between a whisker and a round obstacle is solved, considering three factors: large deformation of the whisker, size of the obstacle, and frictional effect of the interface. Force and energy histories during the contact are analyzed under two motion modes: translation and rotation. Results show that the rotational mode is preferred in nature, because rotation of a whisker over an obstacle requires less energy for frictional dissipation. In addition, there are two types of detachment during the slip between the whisker and the obstacle. The detachment types are dependent on the whisker’s length and can be explained by the buckling theory of a slender beam.

Relationship between self-care and comprehensive understanding of heart failure and its signs and symptoms

2017 ◽  
Vol 17 (6) ◽  
pp. 496-504 ◽  
Author(s):  
Kyoung Suk Lee ◽  
Debra K Moser ◽  
Kathleen Dracup
Keyword(s):  
Heart Failure ◽  
Confidence Interval ◽  
Self Care ◽  
Signs And Symptoms ◽  
Comprehensive Understanding ◽  
Behavior Scale ◽  
Heart Failure Exacerbation ◽  
The Relationship ◽  
Different Levels ◽  
Care Behavior

Background: Although incomplete understanding of heart failure and its signs and symptoms appears to be a barrier to successful self-care, there are few studies examining the relationship between self-care and levels of comprehensive understanding of heart failure and its signs and symptoms. Aim: To determine whether incomplete understanding of heart failure and its signs and symptoms is associated with self-care in heart failure patients who were recently discharged from the hospital due to heart failure exacerbation. Methods: Patients completed the nine-item European Heart Failure Self-care Behavior scale and questionnaire to assess knowledge of heart failure and its signs and symptoms. Three groups were formed by their different levels of understanding of heart failure and its signs and symptoms. Multivariable linear regression was used to determine whether these three levels of understanding groups predicted self-care after controlling for demographic and clinical variables. Results: Of 571 patients 22.1%, 40.1% and 37.8% had poor, moderate, and complete understanding, respectively. Compared with patients in the poor understanding group, patients in complete and moderate understanding groups were more likely to have better adherence to self-care activities (standardized β = −0.14, 95% confidence interval −3.41, −0.47; standardized β = −0.19, 95% confidence interval −4.26, −1.23, respectively). Conclusions: Fewer than half of the patients had a comprehensive understanding of heart failure and its signs and symptoms, which was associated with poor self-care. Our study suggests that patient education should include contents to promote comprehensive understanding of heart failure and its symptoms, as well as the importance of self-care behaviors.

Aerodynamic study of single corrugated variable-camber morphing aerofoil concept

2021 ◽  
pp. 1-29
Author(s):  
K. Dhileep ◽  
D. Kumar ◽  
P.N. Gautham Vigneswar ◽  
P. Soni ◽  
S. Ghosh ◽  
...  
Keyword(s):  
Finite Volume ◽  
Interpolation Method ◽  
Beam Theory ◽  
Small Deformation ◽  
Aerodynamic Characteristics ◽  
Ansys Fluent ◽  
Aerodynamic Efficiency ◽  
Finite Element Software ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Abstract Camber morphing is an effective way to control the lift generated by any aerofoil and potentially improve the range (as measured by the lift-to-drag ratio) and endurance (as measured by $C_l^{3/2}/C_d$ ). This can be especially useful for fixed-wing Unmanned Aerial Vehicles (UAVs) undergoing different flying manoeuvres and flight phases. This work investigates the aerodynamic characteristics of the NACA0012 aerofoil morphed using a Single Corrugated Variable-Camber (SCVC) morphing approach. Structural analysis and morphed shapes are obtained based on small-deformation beam theory using chain calculations and validated using finite-element software. The aerofoil is then reconstructed from the camber line using a Radial Basis Function (RBF)-based interpolation method (J.H.S. Fincham and M.I. Friswell, “Aerodynamic optimisation of a camber morphing aerofoil,” Aerosp. Sci. Technol., 2015). The aerodynamic analysis is done by employing two different finite-volume solvers (OpenFOAM and ANSYS-Fluent) and a panel method code (XFoil). Results reveal that the aerodynamic coefficients predicted by the two finite-volume solvers using a fully turbulent flow assumption are similar but differ from those predicted by XFoil. The aerodynamic efficiency and endurance factor of morphed aerofoils indicate that morphing is beneficial at moderate to high lift requirements. Further, the optimal morphing angle increases with an increase in the required lift. Finally, it is observed for a fixed angle-of-attack that an optimum morphing angle exists for which the aerodynamic efficiency becomes maximum.

Effect of links deformation on motion precision of parallel manipulator based on flexible dynamics

2017 ◽  
Vol 44 (6) ◽  
pp. 776-787 ◽  
Author(s):  
Chunxia Zhu ◽  
Jay Katupitiya ◽  
Jing Wang
Keyword(s):  
Parallel Manipulator ◽  
High Speed ◽  
Beam Theory ◽  
Parallel Manipulators ◽  
Dynamic Responses ◽  
Axial Deformation ◽  
Content Type ◽  
High Performing ◽  
Coupling Equations ◽  
The Relationship

Purpose Manipulator motion accuracy is a fundamental requirement for precision manufacturing equipment. Light weight manipulators in high speed motions are vulnerable to deformations. The purpose of this work is to analyze the effect of link deformation on the motion precision of parallel manipulators. Design/methodology/approach The flexible dynamics model of the links is first established by applying the Euler–Bernoulli beam theory and the assumed modal method. The rigid-flexible coupling equations of the parallel mechanism are further derived by using the Lagrange multiplier approach. The elastic energy resulting from spiral motion and link deformations are computed and analyzed. Motion errors of the 3-link torque-prismatic-torque parallel manipulator are then evaluated based on its inverse kinematics. The validation experiments are also conducted to verify the numerical results. Findings The lateral deformation and axial deformation are largest at the middle of the driven links. The axial deformation at the middle of the driven link is approximately one-tenth of the transversal deformation. However, the elastic potential energy of the transversal deformation is much smaller than the elastic force generated from axial deformation. Practical implications Knowledge on the relationship between link deformation and motion precision is useful in the design of parallel manipulators for high performing dynamic responses. Originality/value This work establishes the relationship between motion precision and the amount of link deformation in parallel manipulators.

scholarly journals Welfare and citizenship

Intersections ◽  
2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Mariann Dósa
Keyword(s):  
Welfare State ◽  
Democratic Citizenship ◽  
Policy Implications ◽  
Comprehensive Understanding ◽  
Alternative Perspective ◽  
Academic Discourses ◽  
The Relationship ◽  
The Welfare State

Ever since Marshall (1965), the relationship between welfare and citizenship has been a key topic in political and academic discourses, and this interrelationship is still far from being unambiguous. This paper reviews mainstream approaches to the welfare–citizenship nexus and argues that shifting our focus to an alternative perspective – viewing welfare as an agent of citizenship socialisation – provides a more comprehensive understanding of both democratic citizenship as a concept and its interrelationship with the welfare state. This view broadens our understanding of the functions of welfare, being a key agent of democracy among others; therefore it has crucial policy implications.   

The relationship between the knee adduction torque and medial contact force during gait

2006 ◽  
Vol 39 ◽  
pp. S70 ◽  
Author(s):  
D. Zhao ◽  
S.A. Banks ◽  
K. Mitchell ◽  
D. D'Lima ◽  
C. Colwell ◽  
...  
Keyword(s):  
Contact Force ◽  
The Relationship

Study on Machining Deformation Errors in Spiral Finish Milling of Thin-Walled Blades

2011 ◽  
Vol 314-316 ◽  
pp. 1773-1777
Author(s):  
Wei Wei Liu ◽  
Pei Chen ◽  
Xiao Juan Gao ◽  
Chen Wei Shan ◽  
Min Wan
Keyword(s):  
Geometric Dimension ◽  
Beam Theory ◽  
Milling Process ◽  
Simplified Model ◽  
Machining Deformation ◽  
Proposed Model ◽  
Thin Walled ◽  
The Relationship ◽  
Torsion Deformation

In this paper, a new procedure is proposed to study the deformation errors for spiral milling process of blade, which can be simplified as a stepwise beam based on the geometry and clamping characteristics. Kirchhoff beam theory is adopted to analyze the bending and torsion deformation. The relationship between machining deformation errors and the workpiece’s geometric dimension are also established based on the simplified model. Corresponding algorithms are realized by MATLAB codes. Experiment test shows that the results predicted by the proposed model are in well agreement with measured ones.

CEO Overconfidence and the Effects of Equity-Based Compensation on Strategic Risk-Taking in the U.S. Restaurant Industry

2014 ◽  
Vol 42 (2) ◽  
pp. 224-259 ◽  
Author(s):  
Kwanglim Seo ◽  
Amit Sharma
Keyword(s):  
Risk Behaviors ◽  
Empirical Analysis ◽  
Risk Taking ◽  
Restaurant Industry ◽  
Positive Relation ◽  
Comprehensive Understanding ◽  
Strategic Risk ◽  
Strategic Risk Taking ◽  
The Relationship ◽  
The U.S

The purpose of this study was to investigate (a) the moderating effect of CEO overconfidence on the relationship between equity-based compensation and strategic risk-taking and (b) the relationship between franchising and strategic risk-taking in the U.S. restaurant industry. Given wide use of a franchise system among U.S. restaurant firms, an understanding of the association between equity-based compensation and strategic risk-taking relative to CEOs’ risk behaviors seems particularly important. We conducted our empirical analysis in the U.S. restaurant industry using a sample of 659 firm-year observations from 1992 to 2013. Our findings showed that (a) overconfident CEOs, while holding equity-based compensation, tended to take on more strategically risky investments, and (b) there was a positive relation between franchising and risk-taking. Considering the behavioral and industry-specific characteristics, study findings could provide a more comprehensive understanding of how equity-based compensation influences strategic risk-taking in the U.S. restaurant industry.

Substitutes or complements? Individual-focused and group-focused transformational leadership in different organizational structures in new firms

2017 ◽  
Vol 38 (5) ◽  
pp. 699-718 ◽  
Author(s):  
Xiumei Zhu ◽  
Mingxu Bao
Keyword(s):  
Transformational Leadership ◽  
Organizational Structure ◽  
Design Methodology ◽  
Organizational Structures ◽  
New Firms ◽  
Comprehensive Understanding ◽  
Content Type ◽  
Significant Performance ◽  
Established Firms ◽  
The Relationship

Purpose The significant performance implications of individual-focused and group-focused transformational leadership have been documented for established firms, but the issue of whether they are complementary or substitutive still remains a puzzle, and whether their relationship differs in new firms remains unanswered. The purpose of this paper is to investigate the relationship between individual-focused and group-focused transformational leadership in different organizational structures in new firms. Design/methodology/approach The study draws on survey data of 209 questionnaires from 63 teams in 63 new firms in China. Findings The results suggest that individual-focused and group-focused transformational leadership are substitutive when the organizational structure is mechanistic, and are complementary when the structure is organic. Originality/value The study contributes to the debate on the relationship between individual-focused and group-focused transformational leadership by comparing organizational structure characteristics and offering a comprehensive understanding of the issue.

Stability Analysis of Planar Grasp with 2D-Virtual Spring Model

1999 ◽  
Vol 11 (4) ◽  
pp. 274-282 ◽  
Author(s):  
Takayoshi Yamada ◽  
◽  
Sushanta Kumar Saha ◽  
Nobuharu Mimura ◽  
Yasuyuki Funahashi ◽  
...  
Keyword(s):  
Contact Force ◽  
External Disturbance ◽  
Rolling Contact ◽  
Initial Contact ◽  
Spring Model ◽  
Spring Stiffness ◽  
Grasp Stability ◽  
Stiffness Matrices ◽  
The Relationship ◽  
Special Case

We analyze stability of planar grasp using a 2D virtual spring model. A 2D virtual spring model is widely used to explore frictionless grasp, but the direction of contact force has not been studied for a grasped object displaced by external disturbance. Finger displacement is restricted to the normal at initial contact. We introduce a 2D spring model for a frictionless case. The direction of contact force is explicitly formulated. Using potential energy, we analyze stability of frictionless grasp and show that the 1D-spring model is a special case of our proposed 2D-spring model. Frictional grasp stability is also studied using rolling contact. Numerical examples of 2-fingered grasp demonstrate the effects of parameters such as spring stiffness and contact force. It is shown that an optimum force exists for stabilizing frictionless grasp. It is proved that friction enhances grasp stability from the relationship between frictionless and frictional stiffness matrices. Stiffness conditions for stabilizing 3-fingered grasp is clarified.

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