bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictors of Home Health Care Services for Cerebral Vascular Disease Patients in Taiwan
Authors: Li I‐Chuan , Chang, M.S.N., R.N. Tsui‐Ming
Published: January 2004

Abstract  The National Health Insurance in Taiwan has rigid regulations for reimbursing home nursing care with payment only for technical/skill care such as changing nasogastric tubes, urine catheters, and tracheal tubes, wound care, and specimen collection. Patients with chronic illnesses who reside at home, however, require care that is holistic and focuses on wellness rather than illness. Cerebral vascular disease (CVD) patients are the largest group receiving home nursing care. They qualify for reimbursement under NHI. The purposes of this study were to quantify the home health care (HHC) needs of CVD patients and to understand predictors for HHC services for CVD patients in Taiwan. A descriptive correlation design was used to examine the relationship between a CVD patient's health status and the need for HHC services. In total, 195 patients were interviewed by one trained research assistant, with 124 patients being from Taipei (an urban area in Taiwan) and the remaining 71 from I‐lan (a rural area in Taiwan). The mean age of subjects was 74.8 years, with 60% of the sample being female. Physiological health status scores (M = 2.56, SD = 0.58, range = 1–5) were worse than the psychosocial health status scores (M = 2.37, SD = 0.91, range = 1–5), which indicates that the need for health education and skilled nursing services was higher than referral services for professional HHC services. Results suggest that there is a need to develop and shape NHI policy to cover more holistic HHC services for CVD patients.
Knowledge and Attitudes of Nurses Working in Sexual Health Clinics in the United Kingdom Toward Post‐Sexual Exposure Prophylaxis for HIV Infection
Authors: Hayter Mark
Published: January 2004

Abstract  The use of anti‐human immunodeficiency virus (HIV) drugs after occupational exposure to HIV is a proven method of preventing some HIV infections. There is anecdotal evidence that this treatment is being used to treat recently exposed sexual contacts of HIV infection, known as non‐occupational post‐exposure prophylaxis (NONOPEP). This raises the issues of the impact of such treatment on sexual behavior and public health. Six hundred questionnaires were distributed to nurses working in sexual health clinics. Four hundred and six (67%) were returned. Questionnaires contained items related to awareness of HIV NONOPEP and items included attitudes related to its use. Seventy two percent of respondents were aware of HIV NONOPEP, and 17% had experience of its use in their clinic. Twenty one percent of respondents indicated that their clinic had a specific HIV NONOPEP policy. In relation to attitudes, practitioners were more positive of NONOPEP in relation to an HIV exposure within a long‐term relationship than exposure within a casual relationship, indicating that the mode of HIV exposure was a factor in the justification of NONOPEP. Practitioners seemed to support the notion that HIV NONOPEP use in a casual exposure may increase the likelihood of unsafe sexual practice; however, practitioners with experience were less likely to express this view. It is suggested that an informed debate and NONOPEP policy development within all sexual health clinics will militate against judgmental views affecting access and care.
The Interaction Model of Client Health Behavior as a Conceptual Guide in the Explanation of Children's Health Behaviors
Authors: Robinson Carolyn H. , Thomas Sandra P.
Published: January 2004

Abstract  This study used the Interaction Model of Client Health Behavior (IMCHB) as a conceptual guide to explain the correlates of children's diet and physical activity and explore the relationships of sex with their diet and physical activity of the school‐aged child. A descriptive correlational study was conducted on 371 fifth‐grade students and their parents. Information on the family's demographics, health experience, social influence, and environmental resources was collected, as well as data on the children's intrinsic motivation, cognitive appraisal, and affective response to food/physical activity. Children's self‐reports on diet and physical activity were collected, as were parents' self‐reports on health habits. Food preferences and diet self‐efficacy explained the most variance in diet behavior for girls and boys. Girls scored healthier on food preferences and diet self‐efficacy than did boys, but no difference was detected in their diet behavior. Girls participated in more low‐intensity physical activity, but boys participated in more high‐intensity physical activity than did girls. Findings provide strong support for the use of the IMCHB to explain children's diet but weak support for the explanation of children's physical activity. Further study of additional factors predictive of physical activity is indicated.
A Comparison of Health Practices of Canadian and Jordanian Nursing Students
Authors: Haddad Linda , Kane Debbie , Rajacich Dale , Cameron Sheila , Al‐Ma'aitah Rowaida
Published: January 2004

Abstract  The purpose of this study was to compare health‐promoting practices of Canadian (n = 49) and Jordanian (n = 44) first‐year nursing students using the revised Health‐Promoting Lifestyle Profile II. Results indicated significant differences between the groups on three subscales: health responsibility, physical activity, and interpersonal relations; however, both groups had similarly low scores. Implications for nurse educators are discussed from both curricular and cross‐cultural perspective that focuses on health‐promotion activities and programs.
Congressional Supervision of America's Secret Agencies: The Experience and Legacy of the Church Committee
Authors: Johnson Loch K.
Published: January 2004

In 1947, the United States created a modern intelligence community to guard against another surprise attack like the one at Pearl Harbor. This community consists of 13 major agencies, among them the CIA and the FBI. Concealed from public view, they pose a significant challenge to the concept of government accountability in a democratic society. This article examines the failure of congressional lawmakers to hold the secret agencies accountable during the Cold War. Contrary to recent theoretical research on legislative oversight, which suggests reasons that accountability has been strong in the United States, this study finds that a weak system of legislative review has permitted a dangerous erosion of civil liberties. The study also explores the efforts of the Church Committee in 1975 to fashion new safeguards that would reduce the probability of further abuse of power by the intelligence community.
E‐Government and the Transformation of Service Delivery and Citizen Attitudes
Authors: West Darrell M.
Published: January 2004

The impact of new technology on public‐sector service delivery and citizens' attitudes about government has long been debated by political observers. This article assesses the consequences ofe‐government for service delivery, democratic responsiveness, and public attitudes over the last three years. Research examines the content of e‐government to investigate whether it is taking advantage of the interactive features of the World Wide Web to improve service delivery, democratic responsiveness, and public outreach. In addition, a national public opinion survey examines the ability of e‐government to influence citizens' views about government and their confidence in the effectiveness of service delivery. Using both Web site content as well as public assessments, I argue that, in some respects, the e‐government revolution has fallen short of its potential to transform service delivery and public trust in government. It does, however, have the possibility of enhancing democratic responsiveness and boosting beliefs that government is effective.
Strategy and Accountability: Structural Reform Litigation and Public Management
Authors: Bertelli Anthony Michael
Published: January 2004

Structural reform litigation involves legal action against public bureaucracies alleging that an official has violated the legal rights of an agency's client. A pattern of rights infringements raises the specter of systemic dysfunction. If the court finds for the plaintiffs, or if the defendant agency agrees to settle, the remedy reconstitutes agency operations. What are the incentives faced by public managers whose agencies are involved in structural reform litigation? How might public managers retain public accountability while strategically using the institutional arrangements present in such cases? This article examines these questions through a spatial bargaining model and discusses its analytical implications in the context of a comprehensive suit against the child welfare agency in Kansas City, Missouri.
Public Meetings and the Democratic Process
Authors: Adams Brian
Published: January 2004

Public meetings are frequently attacked as useless democratic rituals that lack deliberative qualities and fail to give citizens a voice in the policy process. Do public meetings have a role to play in fostering citizen participation in policy making? While many of the criticisms leveled against public meetings have merit, I argue that they do. In this article, I explore the functions that city council and school board meetings serve. While they may not be very good at accomplishing their primary goal of giving citizens the opportunity to directly influence decisions made by governing bodies, they can be used to achieve other ends, such as sending information to officials and setting the agenda. As a complement to deliberative political structures, public meetings have a role to play by offering a venue in which citizens can achieve their political goals, thereby enhancing governmental accountability and responsiveness.
Citizen Participation in Decision Making: Is It Worth the Effort?
Authors: Irvin Renée A. , Stansbury John
Published: January 2004

It is widely argued that increased community participation in government decision making produces many important benefits. Dissent is rare: It is difficult to envision anything but positive outcomes from citizens joining the policy process, collaborating with others and reaching consensus to bring about positive social and environmental change. This article, motivated by contextual problems encountered in a participatory watershed management initiative, reviews the citizen‐participation literature and analyzes key considerations in determining whether community participation is an effective policy‐making tool. We list conditions under which community participation may be costly and ineffective and when it can thrive and produce the greatest gains in effective citizen governance. From the detritus of an unsuccessful citizen‐participation effort, we arrive at a more informed approach to guide policy makers in choosing a decision‐making process that is appropriate for a community's particular needs.
Formal Procedures, Informal Processes, Accountability, and Responsiveness in Bureaucratic Policy Making: An Institutional Policy Analysis
Authors: West William F.
Published: January 2004

This study examines the role of public notice and comment in the development of 42 rules. These procedures can provide useful information to policy makers about the preferences of those who stand to be affected by agency actions. More importantly, they serve as cues for the accommodation of interests and the resolution of conflict through processes that are grounded in agencies' accountability to political officials. Yet, an examination of the interrelationship between formal, procedural constraints and the informal processes surrounding them reveals that the effects of notice and comment in promoting bureaucratic responsiveness are limited in ways that have received little systematic analysis. A consideration of the tension between the instrumental goal of procedural accountability and the political tasks that often dominate bureaucratic policy making suggests that it is desirable to return to the original use of notice and comment as a device for exposing agencies to the views of affected interests.
Decentralization and Democratic Instability: The Case of Costa Rica
Authors: Ryan Jeffrey J.
Published: January 2004

This article examines the consequences of the decentralization process that is under way in Costa Rica and which may undermine, rather than bolster, democracy in that country. I first outline three key contextual variables relating to the reform process: existing sociopolitical realities (constructing local legitimacy), the dynamics of the reform process (bottom‐up versus top‐down), and the timing or sequencing of the proposed reforms (what is being decentralized and when). Though I focus here on Costa Rica, these three variables are generally applicable in any case of decentralization. After considering these contextual factors, I evaluate the likelihood of four negative side effects arising from the ongoing decentralization process: party‐system fragmentation, reinforced or mutated clientelism, intermunicipal conflict and polarization, and local government instability. Early evidence suggests that some of these effects, particularly party‐system fragmentation and municipal instability, have begun to manifest themselves.
Routes to Scholarly Success in Public Administration: Is There a Right Path?
Authors: Schroeder Larry , O'Leary Rosemary , Jones Dale , Poocharoen Ora‐orn
Published: January 2004

The Successful Scholars Project examined the determinants of successful public administration scholars. We surveyed the top 89 public administration scholars alive today (nominated by leaders of five national organizations) and asked them to rank a set of characteristics and behaviors that may have helped them achieve their success. We then analyzed the curricula vitae of 63 of the scholars. This article reports our study's findings and the recommendations of our successful scholars. Scholars heralded good methodological training and quality mentoring as significant. For research, choosing important, cutting‐edge issues to write about, not following fads, being oneself, and publishing quality works were touted as important. Presenting research at national conferences also was highly recommended (while chairing committees and serving as discussants were not). Most scholars recommended steering away from administrative positions and university politics. We conclude with lessons for budding public administration scholars as well as lessons for designing public administration doctoral programs.
Civic Engagement and Public Policy Making in America
Authors: Doamekpor Francois K.
Published: January 2004

Larry N. Gerston, Public Policymaking in a Democratic Society: A Guide to Civic Engagement

Thomas A. Birkland, An Introduction to the Policy Process: Theories, Concepts, and Models of Public Policy Making

Mark E. Rushefsky, Public Policy in the United States: At the Dawn of the Twenty‐First Century
The Pursuit of Equality in Public Administration
Authors: Cheever Kathryn A.L.
Published: January 2004

Louis Kaplow and Steven Shavell, Fairness versus Welfare

Samuel Leiter and William M. Leiter, Affirmative Action in Antidiscrimination Law and Policy: An Overview and Synthesis

Stephen L. Ross and John Yinger, The Color of Credit: Mortgage Discrimination, Research Methodology, and Fair‐Lending Enforcement
BOOK REVIEW
Authors: Bigger J Thomas
Published: January 2004

edited by Ihor Gussak, and Charles Antzelevitch, coedited by Stephen C. Hammill, Win‐Kuang Shen, Preben Bjerregaard. Humana Press Inc., Totowa, New Jersey, 2003
The Imprisonment Crisis in America: Introduction
Authors: Shelden Randall G.
Published: January 2004

This article provides an overview of recent trends in imprisonment rates in America and introduces the articles in this issue of The Review of Policy Research. Incarceration rates have increased by more than 500 percent since the early 1970s and have now reached a rate of almost 700, higher than anywhere else in the world. The impact has been particularly hard on racial minorities, especially women (whose incarceration rate went from around 8 in 1975 to 59 in 2001). The “war on drugs” has been one of the main reasons behind the increases in imprisonment, along with the more general “get tough on crime” movement that began in the late 1970s. The articles in this issue center around how this recent trend in incarceration impacts the entire society, but especially poor communities. Several of the articles focus on race, age and gender as important variables, in addition to the tendency of the parole system to sort of “recycle” released prisoners back into the prison system.
The Risks and Needs of the Returning Prisoner Population
Authors: Austin James , Hardyman Patricia L.
Published: January 2004

There is a growing interest in the threat posed by the increase in the number of prisoners released from prison each year. Some have argued that unless new services and programs are funded, the increasing waves of released prisoners will pose a major threat to public safety in general. This paper reexamines these and other issues and finds that a significant portion of released prisoners pose little if any threat to public safety and that the current parole supervision system often serves to increase rather than reduce recidivism. While released prisoners have significant social, economic, residential, and family needs, they are not sufficient to restrict their release from prison.
Women Offenders and the Gendered Effects of Public Policy1
Authors: Bloom Barbara , Owen Barbara , Covington Stephanie
Published: January 2004

At 17%, women represent a significant proportion of all offenders under criminal justice supervision in the US. Drawing on the findings from their report, “Gender‐Responsive Strategies: Research, Practice, and Guiding Principles for Women Offenders,” the authors maintain that public policy has ignored the context of women's lives and that women offenders have disproportionately suffered from the impact of ill‐informed public policy. This discussion of the implications of gender within the criminal justice system is based on a simple assumption: responding to the differences between women and men in criminal behavior and to their antecedents is critical to gender‐responsive policy. Building on the pathway theoretical perspective, we find that in addition to the gendered impact of the war on drugs, policy changes in welfare reform, housing, and other social policy arenas combine to create a disparate impact on drug abusing women and women of color. Key policy areas affecting the lives of women offenders and their children include welfare benefits, drug treatment, housing, education, employment, and reunification with children. We conclude that addressing the realities of women's lives through gender‐responsive policy and programs is fundamental to improved outcomes at all criminal justice phases. A blueprint for gender‐responsive policy development is described through six guiding principles and their policy implications.
Commerce with Criminals: The New Colonialism in Criminal Justice
Authors: Hallett Michael
Published: January 2004

This article examines the reappearance of for‐profit imprisonment in the US by focusing specifically on the racial and colonialistic history of imprisonment for private profit in America. The article documents that during the two periods of American history in which corrections policy facilitated wholesale private profit through imprisonment, first during the proprietary operation of the convict lease system in the mid 1860s and again today (since the mid‐1980s), incarceration of disproportionately large numbers of African American men has been the industry's chief source of revenue. The article demonstrates a renewed focus on African American crime as the chief source of private profit in today's second era of African American mass imprisonment. The article notes the return of a transnational system of commerce capitalizing on economically and politically dispossessed prisoners for its coercive system of economic production.
A Failure of Good Intentions: An Analysis of Juvenile Justice Reform in San Francisco during the 1990s
Authors: Macallair Daniel , Males Mike
Published: January 2004

This study examines the impact of juvenile justice on San Francisco's youth detention population during the 1990s. Because successful juvenile justice reform is measured by reductions in both detention populations and the disproportionate impact on minority youth, this study attempts to evaluate two closely related issues: (1) Did San Francisco juvenile justice reform lead to reductions in juvenile detention bookings? (2) Did San Francisco juvenile justice reform reduce disproportionate minority confinement? The results of the study demonstrated that in fact neither of these results occurred. The data clearly show that what happened instead was “net widening” whereby offenders previously excluded from the juvenile justice system were processed. This was especially the case for minority females, whose rate of detention increased more than any other group. Implications for social policies are discussed.
Race, Class, and the Development of Criminal Justice Policy1
Authors: Mauer Marc
Published: January 2004

Racial disparities in the criminal justice system are profound and well documented. A range of scholarship has examined these trends to assess the degree to which they result from biased decision making at various levels of the justice system. Also key to understanding the origin of these disparities is an analysis of the race and class determinants of criminal justice policy. This can be seen most clearly in the development of drug policy, but also in the means by which policy choices in law enforcement, prosecution, and sentencing are formulated. To the extent that crime is perceived as a “black problem,” the means by which the problem is addressed and the resulting punitiveness of the approach serve to exacerbate societal inequalities.
Kentucky's Perpetual Prisoner Machine: It's about Money1
Authors: Richards Stephen C. , Austin James , Jones Richard S.
Published: January 2004

Kentucky is currently facing a severe budget crisis and is seeking ways to lower its prison and community corrections costs. This article focuses on our study of the prison and parole experience of men and women in Kentucky. What we found is a virtual “perpetual incarceration machine” where prisoners are recycled from prison to parole and back to prison. The following discussion includes: Kentucky's prison population continues to grow, parole failure, methods, description of interview samples, interview data, the structure producing parole failure, and Kentucky's perpetual incarceration mechine. Based on our findings, several promising reforms are recommended that if implemented would serve to reduce the prison population and the rate of parole failure.
Postsovereign Governance in a Globalizing and Fragmenting World: The Case of Mexico
Authors: Morales‐Moreno Isidro
Published: January 2004

Globalization and “global governance” have become the buzzwords at the turn of the century in order to name and explain the emerging post‐Cold War international order. The first one makes reference to the technological revolution that is modifying our notions of space, time, and production, while the latter attempts to illustrate how power and its regulatory practices are being transformed among polities. We discuss these two notions in the first part of this essay to argue that, in fact, the emerging “global” order will be different from that grounded on state‐centered notions of territory and sovereignty. Our arguments focus on the Mexican case to highlight how this country is moving from an inward‐looking, state‐centered, authoritarian machinery of governance, to a postsovereign, principle‐based, multilayered governance structure. This transition has mainly manifested in the governance mechanisms of corporate and human rights. This does not mean that policy tools of the “ancient regime” have completely disappeared. State‐centered structures of governance will remain important during this stage of economic and political change. Areas moving into postsovereign and principled regulatory practices will overlap with those that remain under the monopoly of national bureaucracies. Though Mexico's economic and political change could be explained as a reactive movement against the collapse of the state‐centered authoritarian model, an important conclusion of this essay is that the emerging pattern of postsovereign and principled bureaucratic governance will play a major role in shaping the future of those changes.
Gait asymmetry in patients with limb length discrepancy
Authors: Perttunen J. R. , Anttila E. , Södergård J. , Merikanto J. , Komi P. V.
Published: January 2004

Foot loading patterns and neuromuscular function of both limbs during walking were investigated on 25 patients with limb length discrepancy. Plantar pressures and 2‐D ground reaction forces were recorded simultaneously with electromyographic activities at two different walking speeds. Bilateral comparison indicated that moderate limb length discrepancies resulted in asymmetrical gait patterns. The duration of the stance phase was reduced in the short limb in both walking speeds. The vertical ground reaction force (F) in the push‐off phase was greater in the long limb both at normal (1.33 (SO, 0.05 BW) vs. 1.29 (SD, 0.09 BW)) (P=0.0027) and fast walking speed (1.55 (SD, 0.11) vs. 1.48 (SD, 0.15 BW)) (P=0.001). Peak plantar pressures were higher under the big toe in the long leg and the heel‐off occurred faster. The push‐off phase was initiated earlier in the short leg. The maximum isometric torque of the long limb was considerably greater (673 Nm vs. 239 Nm) (P=0.026). The results imply that the loading of the long limb is greater and the foot loading patterns shifted more to the forefoot in the long, limb to compensate walking disturbances caused by limb length discrepancies.
Tubular Adhesive Joints Under Axial Load
Authors: Pugno N. , Carpinteri A.
Published: January 2004

In this paper a general study on tubular adhesive joint under axial load is presented. We focus our attention on both static and dynamic behavior of the joint, including shear and normal stresses and strains in the adhesive layer, joint optimization, failure load for brittle crack propagation, and crack detection based on free vibrations. First, we have considered the shear and normal stresses and strains in the adhesive layer to propose an optimization to uniform axial strength (UAS) and to reduce the stress peaks in the bond. The stress analysis confirms that the maximum shear stresses are attained at the ends of the adhesive and that the peak of maximum shear stress is reached at the end of the stiffer tube and does not tend to zero as the adhesive length approaches infinity. A fracture energy criterion to predict brittle crack propagation for conventional and optimized joint is presented. The stability of brittle crack propagation and the strength of the joint, as well as the ductile-brittle failure transition, are analyzed. A detection method to predict crack severity, based on joint dynamic behavior, is also proposed. The crack detection is achieved through the determination of the axial natural frequencies of the joint as a function of the crack length, by determining the roots of a determinantal equation.
Dynamic Characteristics of Elastic Bonding in Composite Laminates: A Free Vibration Study
Authors: Liew K. M. , Zhang J. Z. , Ng T. Y. , Reddy J. N.
Published: January 2004

In conventional analyses of composite laminates, the assumption of perfect bonding of adjoining layers is well accepted, although this is an oversimplification of the reality. It is possible that the bond strength may be less than that of the laminae. Thus, the study of weak bonding is an interesting focus area. In this study, an elastic bonding model based on three-dimensional theory of elasticity in a layerwise framework is used to study composite laminates. The differential quadrature (DQ) discretization is used to analyze the layerwise model. The present model enables the simulation of actual bonding stress states in laminated structures. The interfacial characteristics of transverse stress continuity as well as the kinematic continuity conditions are satisfied through the inclusion of the elastic bonding layer. The present model is employed to investigate the free vibration of thick rectangular cross-ply laminates of different boundary conditions and lamination schemes.
Higher-Order Beam Theories for Mode II Fracture of Unidirectional Composites
Authors: Kumar D. V. T. G. Pavan , Prasad B. K. Raghu
Published: January 2004

Mathematical models, for the stress analyses of unidirectional end notch flexure and end notch cantilever specimens using classical beam theory, first, second, and third-order shear deformation beam theories, have been developed to determine the interlaminar fracture toughness of unidirectional composites in mode II. In the present study, appropriate matching conditions, in terms of generalized displacements and stress resultants, have been derived and applied at the crack tip by enforcing the displacement continuity at the crack tip in conjunction with the variational equation. Strain energy release rate has been calculated using compliance approach. The compliance and strain energy release rate obtained from present formulations have been compared with the existing experimental, analytical, and finite element results and found that results from third-order shear deformation beam theory are in close agreement with the existing experimental and finite element results.
Constant Flux Diffusion Across a Corner
Authors: Wang C. Y.
Published: January 2004

The temperature distribution of a curved barrier heated by constant flux on one side is studied. Both the right-angled corner and the rounded corner are solved by the method of domain decomposition and matching. It is found that hot spot temperatures may reach 2.5 times that of a flat barrier but may be tempered with appropriate rounding at the corner.
Application of a Hybrid Method to the Solution of the Nonlinear Burgers’ Equation
Authors: Kuo Bor-Lih , Chen Chao-Kuang
Published: January 2004

This paper presents the use of a hybrid method which combines differential transformation and finite difference approximation techniques in the solution of the nonlinear Burgers’ equation for various values of Reynolds number including high values. In order to demonstrate the accuracy and validity of the proposed method, it is used to solve several examples of Burgers’ equation, with each example having different initial conditions and boundary conditions. It is found that the results obtained are in good agreement with the analytical solutions, and that the results are more accurate than those provided by other approximate numerical methods.
Nonstick and Stick-Slip Motion of a Coulomb-Damped Belt Drive System Subjected to Multifrequency Excitations
Authors: Cheng G. , Zu J. W.
Published: January 2004

In this paper, the rotational vibration of a belt drive system with a dry friction tensioner subjected to multiple harmonic excitations is studied. The work is focused on the impact of the dry friction torque combined with the multiexcitation frequencies on dynamic characteristics of the system. An analytical solution procedure is developed for the first time to predict two kinds of periodic responses of the system, i.e., nonstop and one-stop motion characterized by the nonstick and stick-slip vibration of the tensioner arm in the system, respectively. Utilizing this method, parametric studies are carried out to obtain the frequency response of a prototypical belt drive system subjected to harmonic excitations from both the driving and driven pulleys. It is found that the tensioner Coulomb friction torque has a significant impact on the amplitude response of the system—it reduces the vibration amplitude of the tensioner arm, but for other components in the belt system it can either decrease or increase the amplitudes under different situations. Furthermore, if the excitation frequency from the driving pulley is larger than or equal to that from the driven pulley, the system vibration amplitudes are much larger than those under the opposite condition.
The Stress Field Caused by a Circular Cylindrical Inclusion in a Transversely Isotropic Elastic Solid
Authors: Hasegawa H. , Kisaki M.
Published: January 2004

Exact solutions are presented in closed form for the axisymmetric stress and displacement fields caused by a circular solid cylindrical inclusion with uniform eigenstrain in a transversely isotropic elastic solid. This is an extension of a previous paper for an isotropic elastic solid to a transversely isotropic solid. The strain energy is also shown. The method of Green’s functions is used. The numerical results for stress distributions are compared with those for an isotropic elastic solid.
Effective Constitutive Equations for Porous Elastic Materials at Finite Strains and Superimposed Finite Strains
Authors: Levin V. A. , Zingermann K. M.
Published: January 2004

A method is developed for derivation of effective constitutive equations for porous nonlinear-elastic materials undergoing finite strains. It is shown that the effective constitutive equations that are derived using the proposed approach do not change if a rigid motion is superimposed on the deformation. An approach is proposed for the computation of effective characteristics for nonlinear-elastic materials in which pores are originated after a preliminary loading. This approach is based on the theory of superimposed finite deformations. The results of computations are presented for plane strain, when pores are distributed uniformly.
Fiber-Reinforced Membrane Models of McKibben Actuators
Authors: Liu W. , Rahn C. R.
Published: January 2004

A McKibben actuator consists of an internally pressurized elastic cylindrical tube covered by a shell braided with two families of inextensible fibers woven at equal and opposite angles to the longitudinal axis. Increasing internal pressure causes the actuator to expand radially and, due to the fiber constraint, contract longitudinally. This contraction provides a large force that can be used for robotic actuation. Based on large deformation membrane theory, the actuator is modeled as a fiber-reinforced cylinder with applied inner pressure and axial load. Given the initial shape, material parameters, axial load, and pressure, the analytical model predicts the deformed actuator shape, fiber angle, and fiber and membrane stresses. The analytical results show that for a long and thin actuator the deformed fiber angle approaches 54°44′ at infinite pressure. The actuator elongates and contracts for actuators with initial angles above and below 54°44′ degrees, respectively. For short and thick actuators with initial angles relatively close to 0 deg or 90 deg, however, a fiber angle boundary layer extends to the middle of the actuator, limiting possible extension or contraction. The calculated longitudinal strain and radius change match experimental results to within 5%.
Transient Growth Before Coupled-Mode Flutter
Authors: Schmid P. J. , de Langre E.
Published: January 2004

Transient growth of energy is known to occur even in stable dynamical systems due to the non-normality of the underlying linear operator. This has been the object of growing attention in the field of hydrodynamic stability, where linearly stable flows may be found to be strongly nonlinearly unstable as a consequence of transient growth. We apply these concepts to the generic case of coupled-mode flutter, which is a mechanism with important applications in the field of fluid-structure interactions. Using numerical and analytical approaches on a simple system with two degrees-of-freedom and antisymmetric coupling we show that the energy of such a system may grow by a factor of more than 10, before the threshold of coupled-mode flutter is crossed. This growth is a simple consequence of the nonorthogonality of modes arising from the nonconservative forces. These general results are then applied to three cases in the field of flow-induced vibrations: (a) panel flutter (two-degrees-of-freedom model, as used by Dowell) (b) follower force (two-degrees-of-freedom model, as used by Bamberger) and (c) fluid-conveying pipes (two-degree-of-freedom model, as used by Benjamin and Pai¨doussis) for different mass ratios. For these three cases we show that the magnitude of transient growth of mechanical energy before the onset of coupled-mode flutter is substantial enough to cause a significant discrepancy between the apparent threshold of instability and the one predicted by linear stability theory.
Weakly Nonlinear Stability Analysis of Condensate/Evaporating Power-Law Liquid Film Down an Inclined Plane
Authors: Usha R. , Uma B.
Published: January 2004

Weakly nonlinear stability analysis of thin power-law liquid film flowing down an inclined plane including the phase change effects at the interface has been investigated. A normal mode approach and the method of multiple scales are employed to carry out the linear stability solution and the nonlinear stability solution for the film flow system. The results show that both the supercritical stability and subcritical instability are possible for condensate, evaporating and isothermal power-law liquid film down an inclined plane. The stability characteristics of the power-law liquid film show that isothermal and evaporating films are unstable for any value of power-law index ‘n’ while there exists a critical value of power-law index ‘n’ for the case of condensate film above which condensate film flow system is always stable. Thus, the results of the present analysis show that the mass transfer effects play a significant role in modifying the stability characteristics of the non-Newtonian power-law fluid flow system. The condensate (evaporating) power-law fluid film is more stable (unstable) than the isothermal power-law fluid film flowing down an inclined plane.
Tunneling ionization of atoms
Authors: Bisgaard Christer Z. , Madsen Lars Bojer
Published: January 2004

We discuss the theory for the ionization of atoms by tunneling due to a strong external static electric field or an intense low frequency laser field.
Nonoccupational noise: exposures associated with routine activities
Authors: Neitzel Richard , Seixas Noah , Olson John , Daniell William , Goldman Bryan
Published: January 2004

Efforts to characterize nonoccupational noise exposures have focused primarily on infrequent, episodic events. Few studies have assessed noise levels resulting from routine daily activities. In the current study, 112 construction workers wore datalogging noise dosimeters and simultaneously completed activity logs during two phases of data collection. The 81 subjects monitored in phase 1 received logs listing numerous preselected occupational and nonoccupational activities, while the 31 subjects monitored in phase 2 used free-field logs and reported nonoccupational activities in greater detail. Nearly all of the 221 439 1-min intervals of nonoccupational Leq level and activity reporting were below 70 dBA; only a small percentage exceeded 80 dBA. The primary contributor to nonoccupational noise exposure was traveling in a car or bus, while time at home contributed the least. One hundred seventy 24-h Leq levels were computed from the 1-min noise level data. The percentage of phase 2 workday Leq(24) levels which exceeded 80 dBA was higher than that of the nonworkday levels. The mean Leq(24) level of phase 2 workdays was higher than that of nonworkdays, and the difference was statistically significant. Routine nonoccupational noise exposures contributed much less to total noise dose than occupational exposures in the subjects evaluated.
Performance of time- and frequency-domain binaural beamformers based on recorded signals from real rooms
Authors: Lockwood Michael E. , Jones Douglas L. , Bilger Robert C. , Lansing Charissa R. , O’Brien William D. , Wheeler Bruce C. , Feng Albert S.
Published: January 2004

Extraction of a target sound source amidst multiple interfering sound sources is difficult when there are fewer sensors than sources, as is the case for human listeners in the classic cocktail-party situation. This study compares the signal extraction performance of five algorithms using recordings of speech sources made with three different two-microphone arrays in three rooms of varying reverberation time. Test signals, consisting of two to five speech sources, were constructed for each room and array. The signals were processed with each algorithm, and the signal extraction performance was quantified by calculating the signal-to-noise ratio of the output. A frequency-domain minimum-variance distortionless-response beamformer outperformed the time-domain based Frost beamformer and generalized sidelobe canceler for all tests with two or more interfering sound sources, and performed comparably or better than the time-domain algorithms for tests with one interfering sound source. The frequency-domain minimum-variance algorithm offered performance comparable to that of the Peissig–Kollmeier binaural frequency-domain algorithm, but with much less distortion of the target signal. Comparisons were also made to a simple beamformer. In addition, computer simulations illustrate that, when processing speech signals, the chosen implementation of the frequency-domain minimum-variance technique adapts more quickly and accurately than time-domain techniques.
Asymptotic solutions of the inhomogeneous Burgers equation
Authors: Bednarik Michal , Konicek Petr
Published: January 2004

The method of the active second harmonic suppression in resonators is investigated in this paper both analytically and numerically. The resonator is driven by a piston which vibrates with two frequencies. The first one agrees with an eigenfrequency and the second one is equal to the two times higher eigenfrequency. The phase shift of the second piston motion is 180 deg. It is known that for this case it is possible to describe generation of the higher harmonics by means of the inhomogeneous Burgers equation. This model equation was solved for stationary state analytically by a number of authors but only for ideal fluids. Unlike their solutions, new asymptotic solutions are presented here which take into account dissipative effects. The asymptotic solutions are compared with numerical ones. For study of generation higher harmonics the solutions are developed in a spectral form.
Spherical wave propagation through inhomogeneous, anisotropic turbulence: Log-amplitude and phase correlations
Authors: Ostashev Vladimir E. , Wilson D. Keith , Goedecke George H.
Published: January 2004

Inhomogeneity and anisotropy are intrinsic characteristics of daytime and nighttime turbulence in the atmospheric boundary layer. In the present paper, line-of-sight sound propagation through inhomogeneous, anisotropic turbulence with temperature and velocity fluctuations is considered. Starting from a parabolic equation and using the Markov approximation, formulas are derived for the correlation functions and variances of log-amplitude and phase fluctuations of a spherical sound wave. These statistical moments of a sound field are important for many practical applications in atmospheric acoustics. The derived formulas for the correlation functions and variances generalize those already known in the literature for two limiting cases: (a) homogeneous, isotropic turbulence, and (b) inhomogeneous, anisotropic turbulence with temperature fluctuations only. Furthermore, the formulas differ from those for the case of plane wave propagation. Using the derived formulas and Mann’s spectral tensor of velocity fluctuations for shear-driven turbulence, the correlation functions and variances of log-amplitude and phase fluctuations are studied numerically. The results obtained clearly show that turbulence inhomogeneity and anisotropy significantly affect sound propagation in the atmosphere.
Reverberation and frequency attenuation in forests—implications for acoustic communication in animals
Authors: Padgham Mark
Published: January 2004

Rates of reverberative decay and frequency attenuation are measured within two Australian forests. In particular, their dependence on the distance between a source and receiver, and the relative heights of both, is examined. Distance is always the most influential of these factors. The structurally denser of the forests exhibits much slower reverberative decay, although the frequency dependence of reverberation is qualitatively similar in the two forests. There exists a central range of frequencies between 1 and 3 kHz within which reverberation varies relatively little with distance. Attenuation is much greater within the structurally denser forest, and in both forests it generally increases with increasing frequency and distance, although patterns of variation differ between the two forests. Increasing the source height generally reduces reverberation, while increasing the receiver height generally reduces attenuation. These findings have considerable implications for acoustic communication between inhabitants of these forests, particularly for the perching behaviors of birds. Furthermore, this work indicates the ease with which the general acoustic properties of forests can be measured and compared.
Measurement of six acoustical properties of a three-layered medium using resonant frequencies
Authors: Yapura Carlos L. , Kinra Vikram K. , Maslov Konstantin
Published: January 2004

An ultrasonic technique for a simultaneous determination of traveling times and acoustic impedances of three-layered, platelike specimens using a normally incident longitudinal wave is presented. The acoustical properties are determined by minimizing the difference between measured and calculated resonant frequencies in the well-known least-squares sense. The resonant frequencies of the layered structure are deduced, in transmission, from the maxima of the magnitude of the transmission spectrum, or, in reflection, from the π values of the phase of the reflection spectrum. Measurements are carried out in the frequency range 1–20 MHz for steel/aluminum/steel and silver/copper/nickel specimens with individual layer thickness values ranging from 0.3 mm to 2 mm. The differences between the inverted thicknesses and those measured directly with an optical microscope range from −4 μm to +13 μm. Estimated error bounds suggest that the inverted travel times are accurate within ±1 ns with 95% probability.
Steady state unfocused circular aperture beam patterns in nonattenuating and attenuating fluids
Authors: Goldstein Albert
Published: January 2004

Single integral approximate formulas have been derived for the axial and lateral pressure magnitudes in the beam pattern of steady state unfocused circular flat piston sources radiating into nonattenuating and attenuating fluids. The nonattenuating formulas are shown to be highly accurate at shallow beam depths if a normalized form of the beam pattern is utilized. The axial depth of the beginning of the nonattenuated beam pattern far field is found to be at 6.41Y0. It is demonstrated that the nonattenuated lateral beam profile is represented at this and deeper depths by a Jinc function directivity term. Values of α and z are found that permit the attenuated axial pressure to be represented by a plane wave multiplicative attenuation factor. This knowledge should aid in the experimental design of high accuracy attenuation measurements. The shifts in depth of the principal axial pressure maxima and minima due to fluid attenuation are derived. Single integral approximate equations for the attenuated full beam pattern pressure are presented using complex Bessel functions.