Study on the Radial Vibration of an Annular Plate Ultrasonic Concentrator with Edge Section

2011 ◽  
Vol 215 ◽  
pp. 95-102
Author(s):  
H. Xu ◽  
S.Q. Liu
Keyword(s):  
Radial Displacement ◽  
Vibration Mode ◽  
Second Order ◽  
Radius Ratio ◽  
Displacement Amplitude ◽  
Radial Vibration ◽  
Order Resonance ◽  
Resonance Frequencies ◽  
The Relationship ◽  
Edge Section

The radial vibration of an annular ultrasonic concentrator with edge section is studied. Based on the electromechanical analogy, the radial equivalent circuit and the frequency equation of the concentrator are derived, the radial displacement amplitude magnification and the nodal circle equation are given. The relationship between the radial displacement amplitude magnification and radius ratio of the annular vibrator at the first and second order vibration mode is obtained. The relationship between the first and the second order radial resonance frequencies and the radius ratio of the annular edge section concentrator is analyzed. The displacement amplitude magnification of the annular vibrator at the second order resonance is lager than that of the first order vibration mode. Especially, when the radius ratio tends to one, the second order resonance frequency of the annular vibrator tends toward infinity. It can be concluded that there is no higher order vibration mode for a thin-walled circular ring. Furthermore, the experimental results show that the theoretical resonance frequencies and the amplitude magnification are in good agreement with the measured results.

Research on Piezoelectric Tube Stack for Radial Vibration Mode

2013 ◽  
Vol 721 ◽  
pp. 437-442
Author(s):  
Chao Zhong ◽  
Li Kun Wang ◽  
Lei Qin ◽  
Jing Jing Zhou ◽  
Cui Ying Chen ◽  
...  
Keyword(s):  
Vibration Mode ◽  
Analytical Calculation ◽  
Fem Simulation ◽  
Average Radius ◽  
Radial Vibration ◽  
Mechanical Equivalent ◽  
Thin Tube ◽  
Resonance Frequencies ◽  
Simulation Results ◽  
The Relationship

According to electro-mechanical equivalent principle, piezoelectric tube stack electro-mechanical equivalent circuit is derived by the admittance of single piezoelectric thin tube. The resonance frequency of piezoelectric tube stack for radial vibration mode is also calculated. The relationship between resonance frequencies and average radius, thickness and height with radial vibration mode are obtained through analytical calculation. And radial vibration mode is simulated by FEM .Analytical calculation and FEM simulation results are compared. They coincide well with each other.

Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 315-318 ◽  
Author(s):  
K. Momose ◽  
K. Komiya ◽  
A. Uchiyama
Keyword(s):  
Visual System ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Second Order ◽  
First Order ◽  
The Relationship ◽  
Perceived Color ◽  
Second Order Nonlinearity ◽  
Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

Eating Behavior of Brazilian College Students: Influences of Lifestyle, Negative Affectivity, and Personal Characteristics

2020 ◽  
pp. 003151252098308
Author(s):  
Bianca G. Martins ◽  
Wanderson R. da Silva ◽  
João Marôco ◽  
Juliana A. D. B. Campos
Keyword(s):  
College Students ◽  
Eating Behavior ◽  
Emotional Eating ◽  
Eating Behaviors ◽  
Structural Model ◽  
Negative Affectivity ◽  
Personal Characteristics ◽  
Second Order ◽  
The Impact ◽  
The Relationship

In this study we proposed to estimate the impact of lifestyle, negative affectivity, and college students’ personal characteristics on eating behavior. We aimed to verify that negative affectivity moderates the relationship between lifestyle and eating behavior. We assessed eating behaviors of cognitive restraint (CR), uncontrolled eating (UE), and emotional eating (EE)) with the Three-Factor Eating Questionnaire-18. We assessed lifestyle with the Individual Lifestyle Profile, and we assessed negative affectivity with the Depression, Anxiety and Stress Scale-21. We constructed and tested (at p < .05) a hypothetical causal structural model that considered global (second-order) and specific (first-order) lifestyle components, negative affectivity and sample characteristics for each eating behavior dimension. Participants were 1,109 college students ( M age = 20.9, SD = 2.7 years; 65.7% females). We found significant impacts of lifestyle second-order components on negative affectivity (β = −0.57–0.19; p < 0.001–0.01) in all models. Physical and psychological lifestyle components impacted directly only on CR (β=−0.32–0.81; p < 0.001). Negative affectivity impacted UE and EE (β = 0.23–0.30; p < 0.001). For global models, we found no mediation pathways between lifestyle and CR or UE. For specific models, negative affectivity was a mediator between stress management and UE (β=−0.07; p < 0.001). Negative affectivity also mediated the relationship between thoughts of dropping an undergraduate course and UE and EE (β = 0.06–0.08; p < 0.001). Participant sex and weight impacted all eating behavior dimensions (β = 0.08–0.34; p < 0.001–0.01). Age was significant for UE and EE (β=−0,14– −0.09; p < 0.001–0.01). Economic stratum influenced only CR (β = 0.08; p = 0.01). In sum, participants’ lifestyle, negative emotions and personal characteristics were all relevant for eating behavior assessment.

The Geometry of d2y1/dt2 = f (y, ẏ, t) and d2y2/dt2 = g(y, ẏ, t), and Euclidean Spaces

2006 ◽  
Vol 49 (2) ◽  
pp. 170-184
Author(s):  
Richard Atkins
Keyword(s):  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Shortest Paths ◽  
Equivalence Problem ◽  
Second Order ◽  
System Of Differential Equations ◽  
Lagrange Equations ◽  
Invariant Functions ◽  
Underlying Geometry ◽  
The Relationship

AbstractThis paper investigates the relationship between a system of differential equations and the underlying geometry associated with it. The geometry of a surface determines shortest paths, or geodesics connecting nearby points, which are defined as the solutions to a pair of second-order differential equations: the Euler–Lagrange equations of the metric. We ask when the converse holds, that is, when solutions to a system of differential equations reveals an underlying geometry. Specifically, when may the solutions to a given pair of second order ordinary differential equations d2y1/dt2 = f (y, ẏ, t) and d2y2/dt2 = g(y, ẏ, t) be reparameterized by t → T(y, t) so as to give locally the geodesics of a Euclidean space? Our approach is based upon Cartan's method of equivalence. In the second part of the paper, the equivalence problem is solved for a generic pair of second order ordinary differential equations of the above form revealing the existence of 24 invariant functions.

scholarly journals Kinetics and optimization on discoloration of dyeing wastewater by schorl-catalyzed fenton-like reaction

2014 ◽  
Vol 79 (3) ◽  
pp. 361-377 ◽  
Author(s):  
Huan-Yan Xu ◽  
Wei-Chao Liu ◽  
Shu-Yan Qi ◽  
Yan Li ◽  
Yuan Zhao ◽  
...  
Keyword(s):  
Response Surface ◽  
Reaction Rate Constant ◽  
Second Order ◽  
Order Kinetic ◽  
Reaction Conditions ◽  
Design And Optimization ◽  
Order Kinetic Model ◽  
Kinetic Investigations ◽  
The Relationship ◽  
Experimental Design And Optimization

Kinetics and optimization on the discoloration of an active commercial dye, Argazol Blue BFBR (ABB) by heterogeneous Fenton-like reaction catalyzed by natural schorl were investigated in this study. Kinetic investigations revealed that the first-order kinetic model was more favorable to describe the discoloration of ABB at different reaction conditions than the second-order and Behnajady-Modirshahla-Ghanbery models. The relationship between the reaction rate constant k and reaction temperature T followed the Arrhenius equation, with the apparent activation energy Ea of 51.31kJ?mol-1. The central composite design under the response surface methodology was employed for the experimental design and optimization of the ABB discoloration process. The significance of a second order polynomial model for predicting the optimal values of ABB discoloration was evaluated by the analysis of variance and 3D response surface plots for the interactions between two variables were constructed. Then, the optimum conditions were determined.

scholarly journals Integrated cosine functions

1996 ◽  
Vol 19 (3) ◽  
pp. 575-580 ◽  
Author(s):  
Quan Zheng
Keyword(s):  
Banach Space ◽  
Cauchy Problem ◽  
Second Order ◽  
Basic Theory ◽  
Cosine Function ◽  
Integrated Semigroups ◽  
Approximation Theorems ◽  
The Relationship ◽  
Cosine Functions

In order to the second order Cauchy problem(CP2):x″(t)=Ax(t),x(0)=x∈D(An),x″(0)=y∈D(Am)on a Banach space, Arendt and Kellermann recently introduced the integrated cosine function. This paper is concerned with its basic theory, which contain some properties, perturbation and approximation theorems, the relationship to analytic integrated semigroups, interpolation and extrapolation theorems.

Linking transformational leadership and “multi-dimensions” of project success

2019 ◽  
Vol 13 (1) ◽  
pp. 103-127 ◽  
Author(s):  
Umer Zaman ◽  
Shahid Nawaz ◽  
Sidra Tariq ◽  
Asad Afzal Humayoun
Keyword(s):  
Transformational Leadership ◽  
Structural Equation ◽  
Structural Model ◽  
Project Success ◽  
Higher Order ◽  
Project Managers ◽  
Second Order ◽  
Equation Modeling ◽  
Content Type ◽  
The Relationship

Purpose Transformational leadership, flexibility and visibility improves project responsiveness to highly unpredictable and impactful events referred as the ‘black swans’ in mega projects (Bloch et al., 2012; Raziq et al., 2018; Zailani et al., 2016). However, these concepts have never been empirically tested in a single framework to determine their significant impact on multi-dimensional project success. The purpose of this paper is to investigate the interactional effects of project flexibility and project visibility on the relationship between transformational leadership and “multi-dimensions” of project success including meeting design goals; impact on customers and benefits to project-based organization. Design/methodology/approach Empirical data derived from cross-sectional survey of 160 project managers from telecom intensive companies in Pakistan were used to test the conceptual framework developed from recent literature. Partial least squares-structural equation modeling (PLS-SEM) provided detailed analysis of the measurement and structural model. The most recent reflective–formative PLS-SEM approach for higher-order constructs has been introduced. Findings The results indicate that project managers’ transformational leadership (β = 0.348, p < 0.01), project flexibility (β = 0.221, p < 0.01) and project visibility (β = 0.366, p < 0.01) are positively related with the multi-dimensional project success (second-order formative) construct. Interestingly, the relationship between transformational leadership and project success is influenced by significantly negative moderations established through project flexibility (β = −0.100, p < 0.01) and project visibility (β = −0.093, p < 0.05). Research limitations/implications This study in the telecom sector examined the interactional effects of risk mitigating strategies (i.e. project flexibility and project visibility) on the relationship between transformational leadership and multi-dimensional project success. This study creates a basis for future investigations extending to various project types and relevant to different industries especially those involving higher-order (formative) assessments of project success. Practical implications The study findings assist project leaders to meet their escalating commitments in achieving project success from a multi-dimensional standpoint. Additionally, this study underscores a renewed perspective of transformational leadership and project outcomes. Despite prevailing understanding developed through prior research, transformational leadership may become less favorable for project success in conditions of increased flexibility and visibility in projects. Originality/value Earlier studies have overlooked the multi-dimensional nature of project success (second-order formative) construct, despite several attempts to examine the interplay between transformational leadership and project success. Based on the knowledge gap and non-existence of empirical evidence, the authors introduced and empirically tested the moderating role of project flexibility and project visibility in the relationship between transformational leadership and multi-dimensional project success.

scholarly journals Lagrangians, Gauge Functions, and Lie Groups for Semigroup of Second-Order Differential Equations

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Z. E. Musielak ◽  
N. Davachi ◽  
M. Rosario-Franco
Keyword(s):  
Differential Equations ◽  
Lie Groups ◽  
Lie Group ◽  
Algebraic Structure ◽  
Second Order ◽  
Lagrangian Formalism ◽  
Group Approach ◽  
Second Order Differential Equations ◽  
Gauge Functions ◽  
The Relationship

A set of linear second-order differential equations is converted into a semigroup, whose algebraic structure is used to generate novel equations. The Lagrangian formalism based on standard, null, and nonstandard Lagrangians is established for all members of the semigroup. For the null Lagrangians, their corresponding gauge functions are derived. The obtained Lagrangians are either new or generalization of those previously known. The previously developed Lie group approach to derive some equations of the semigroup is also described. It is shown that certain equations of the semigroup cannot be factorized, and therefore, their Lie groups cannot be determined. A possible solution of this problem is proposed, and the relationship between the Lagrangian formalism and the Lie group approach is discussed.

Evaluation of High-Order Resonance of Blade Under Wake Excitation

2010 ◽  
Author(s):  
Lin Li ◽  
Peiyi Wang
Keyword(s):  
Force Field ◽  
Aerodynamic Force ◽  
Engineering Problem ◽  
High Order ◽  
Order Resonance ◽  
High Order Resonance ◽  
Resonance Frequencies ◽  
The Common ◽  
Turbo Machinery ◽  
Two Parameters

Avoiding the low-order resonances of blades is one of the main design goals for a mechanical structure designer of turbo machinery. However, we have to accept that there are resonance frequencies in the operating speed range of the blade, for the following reasons: Firstly, the natural frequencies of the blade are closely spaced sometimes, it is impossible to avoid them all. Secondly, in general, the higher of the resonance frequency, the lower the energy of resonance will be. But in recent 10 years, the high-order blade resonances present more and more frequently in turbo machinery, which induce a lot of HCF problems. As the considerations above, studies on the high-order vibration of blades become necessary and important. In the cascade, the high-order vibration of blades is mainly induced by the wakes from upstream. An obvious difference of the wake excitation from the common excitations resides in its asynchronism, that is, the maximum value of aerodynamic force from wakes at each point doesn’t appear at the same time, because except the frequency, the distribution of the aerodynamic force field depends on two parameters: not only amplitude but also phase angle. Both are functions of coordinates. In this paper, the related position in Euclidean Space between the asynchronous excitation field and the modal displacement of blade were deal with to evaluate the strength of the high-order resonance of blade. The effect of the asynchronous aerodynamic force field on the blade resonance was studied either. Finally a method for evaluation of high-order resonance of blade excited by wake fluid is proposed. A numerical case was studied either, which demonstrates that the proposed evaluation on high-order resonance is practical in engineering problem.

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