bluuebunny/crossref_metadata_2025 huggingface dataset:
“Trabajando Duro Todos Los Días”: Learning From the Life Experiences of Mexican‐Origin Migrant Families*
Authors: Parra‐Cardona José Rubén , Bulock Laurie A. , Imig David R. , Villarruel Francisco A. , Gold Steven J.
Published: June 2006

Abstract: The agricultural economy in the United States has relied heavily on migrant farmworkers and, in particular, on Latinos. However, migrant families remain one of the most disadvantaged groups in the United States. This research focuses on a subsample of migrant families of Mexican origin (n= 13), who participated in the Rural Families Speak multistate study. Qualitative findings described numerous challenges that Mexican‐origin migrant families continue to experience. Results were also illustrative of the resilience of migrant families, which is influenced by specific Latino cultural values and is reflected in the successful adaptation of these families to the challenges associated with a migrant lifestyle.
“It’s a Balancing Act!”: Exploring School/Work/Family Interface Issues Among Bilingual, Rural Nebraska, Paraprofessional Educators
Authors: Dalla Rochelle L. , MoulikGupta Pallabi , Lopez William E. , Jones Vicky
Published: June 2006

Abstract: Nebraska’s rural school districts have a rapidly growing Spanish‐speaking student body and few qualified instructors to meet their educational needs. This investigation examined factors that promote and challenge the ability of rural Nebraska paraprofessional educators to complete an online B.S. program in elementary education, with a K‐12 English as a second language endorsement. Interviews focused on the interface between school, work, and family, with special attention on family system change and adaptation. Twenty‐six bilingual paraprofessional educators enrolled (or formerly enrolled) in the education program were interviewed. Twenty were first‐ (n= 15) or second‐generation (n= 5) immigrant Latino/as. Influences of program involvement on the marital and parent‐child relationships are discussed, as are implications for future work with unique populations.
Prevention Research and Latino Families: Resources for Researchers and Practitioners
Authors: Maldonado‐Molina Mildred M. , Reyes Nenetzin A. , Espinosa‐Hernández Graciela
Published: June 2006

Abstract: This article reviews cultural and methodological considerations when developing effective preventive interventions among Latino families. A prevention approach guides the discussion of five key issues in prevention science, including (a) the role of risk and protective factors, (b) fidelity and adaptation strategies, (c) program effectiveness, (d) methodological consideration, and (e) bridging prevention research and practice. An annotated bibliography complements our discussion of conceptual and methodological considerations and prevention and intervention practices when working with Latinos.
Alfred the Great’s Boethius1
Authors: Discenza Nicole Guenther
Published: June 2006

Alfred the Great’s translation of Boethius’s Consolation of Philosophy into the Old English Boethius is notable both for its richness and for its difficulties. After briefly introducing Boethius and his greatest text, this essay will turn to the OE Boethius and its problems, which include questions about authorship and poor editions. Soon, however, a new electronic and a new print edition will help scholars better see what medieval audiences read. Those audiences included upper‐class laity of some leisure and poorly educated clergy, not the most obvious recipients of Boethius’s difficult prosimetrum – yet Alfred’s translation conveys Boethius’s key themes and shows great interest in both theology and philosophy. At the same time, the Boethius also seeks to inculcate the king’s own sense of the responsibilities of subjects and leaders. Despite its difficulty, later readers found the text worth copying and preserving.
Of Cyder and Sallets: The Hortulan Saints and The Garden of Cyrus
Authors: Preston Claire
Published: June 2006

Little in the way of politics has ever been detected in Thomas Browne’s The Garden of Cyrus (1658). The following essay, however, reconsiders Cyrus in relation to the politically sensitive May Day celebrations of the mid‐seventeenth century, and to the host of orchard and planting manuals which were appearing at the same time, a genre able to contain the ideological, economic and spiritual aspirations of Anglicans and Puritans, Royalists and radicals alike. Like most of Browne’s other major works, Cyrus avoids direct political or pragmatic interventions and instead enacts, structurally and rhetorically, the competing ideas of order which animated the public antagonisms of the late 1650s.
Presenting Romantic Texts: Editorial Theory and Practice
Authors: Bajetta Carlo M.
Published: June 2006

Modern editorial thinking has been much influenced by the practice of editing Romantic texts. Having confronted the complex transmission histories of the poems of Byron, Keats and Shelley, and the ‘multiple authorities’ implicit in the production of many Romantic texts, editors such as Jerome McGann, Jack Stillinger and Donald Reiman started reconsidering the idea of ‘final authorial intention’ and/or the very idea of an ‘edition’ of a given work. Understanding the crucial theoretical issues of Romantic editing means being able to grasp not only the rationale behind current editions of the major writers of the Romantic era, but the very principles of modern textual criticism.
Development and Testing of Tools to Assess Physical Restraint Use
Authors: Edwards Nancy , Danseco Evangeline , Heslin Kathleen , Ploeg Jenny , Santos Josephine , Stansfield Melanie , Davies Barbara
Published: June 2006

Background: To implement best practice in restraint use, healthcare providers and decision makers require current, accurate, and easily accessible information about restraint practices in their setting. There is a need for a reliable and valid instrument that is feasible for use in these settings to rapidly assess physical restraint use.

Method: Two instruments to assess physical restraint use were developed and tested: an observation tool and a chart audit. The instruments were tested in complex continuing care units and rehabilitation units at two healthcare organizations. The restraint use observation tool was administered by trained observers in a series of five observations over a 2‐week period. Chart audits were conducted for a sample of residents. Inter‐rater agreement of the observation tool and chart audit was assessed. Point prevalence estimates were obtained for each site. The time required to use the observation tool and complete chart audits as well as the comparability of findings from the two data sources were described.

Findings: Restraint use observations were completed for 289 patients and chart audits were completed for 207 patients. Prevalence and patterns of restraint use varied between sites and across time periods. Observations took an average of 2.6 (Site A) and 0.6 (Site B) minutes per patient. There was excellent inter‐rater agreement for most items on the observation tool with the exception of whether or not the patient was able to release or loosen the restraint. There was significant concordance but as expected, not complete agreement between paired estimates of prevalence using the observational tool and the chart audit.

Conclusion: The observation and chart audit tools are feasible to use and reliably assess physical restraint use in healthcare organizations. The patient's physical capacity to move independently, the patient's waking status, and the restraint's restriction of mobility are items that should be added to the observation tool. The tools are complementary and should be used in tandem to capture the multifaceted complexity of restraint use in health service organizations.

Worldviews on Evidence‐Based Nursing 2006; 3(2):73–85.
Changing Paradigms from a Historical DSM-III and DSM-IV View Toward an Evidence-Based Definition of Premature Ejaculation. Part II—Proposals for DSM-V and ICD-11
Authors: Waldinger Marcel D. , Schweitzer Dave H.
Published: June 2006

Background

In the Diagnostic and Statistical Manual of Mental Disorders (DSM), a descriptive definition for premature ejaculation (PE) that was based on historical assumptions has been accepted.

Aim

To formulate a new functional definition of PE in the DSM.

Methods

A “syndrome” approach instead of a “complaint” approach is applied and evidence-based data from epidemiological and clinical studies are used.

Results

A new functional definition of PE should pertain to a cluster of “symptoms” of a distinct “syndrome.” A syndrome rather than a descriptive definition should distinguish Lifelong and Acquired PE variants. Evidence-based data also suggest another PE type “Natural Variable PE,” which is not a typical syndrome but rather a cluster of inconsistent symptoms of rapid ejaculation. Moreover, in “Natural Variable PE” the occurrence of rapid ejaculation is not based on neurobiological or psychological pathology, but belongs to the normal variability of sexual performance. Its prevalence is probably much higher than that of Lifelong and Acquired PE. We propose three separate operationalized definitions of these three PE types for the pending DSM-V and ICD-11, which include a quantification of the ejaculation time (intravaginal ejaculation latency time), inability of ejaculatory control, and a description of severity of PE in terms of psychological distress.

Conclusion

The use of the intravaginal ejaculation latency time into the DSM-V and ICD-11 would mean that statistical evidence becomes accepted as one of the mainstays for establishing an evidence-based definition of the three PE types.
Relationship Between Caregiver Knowledge and Socioeconomic Factors on Glycemic Outcomes of Young Children With Diabetes
Authors: Stallwood Lynda
Published: June 2006

PURPOSE.  To describe the relationship between caregiver diabetes knowledge and socioeconomic factors on glycemic outcomes of young children with type 1 diabetes.

DESIGN AND METHODS.  Seventy‐three caregivers of children less than 9 years of age were conveniently sampled and completed the Michigan Diabetes Research and Training Center Diabetes Knowledge Test and a demographic questionnaire.

RESULTS.  Higher caregiver knowledge was associated with lower hemoglobin A

1c

(HbA

1c

) levels, higher income levels, and being married. Thirty‐three (44%) children had HbA

1c

levels within the target range.

PRACTICE IMPLICATIONS.  Perform ongoing knowledge assessments and educational interventions related to deficits, with a special focus on families in lower socioeconomic situations.
Results of an Asthma Disease Management Program in an Urban Pediatric Community Clinic
Authors: Newcomb Patricia
Published: June 2006

PURPOSE.  Asthma is increasing in incidence, but adherence to national diagnosis and treatment guidelines is poor. The Children's Asthma Management Program (CHAMP) was designed and implemented by nurse practitioners to address the problem of inconsistent asthma management.

DESIGN AND METHODS.  This is an outcome‐based evaluation of a novel asthma management program in which practitioners created a structured mechanism for implementing national evidence‐based asthma treatment guidelines.

RESULTS.  Children who completed the program experienced an 85% decrease in hospitalizations for asthma, 87% decrease in emergency room visits for asthma, and 71% decrease in acute office visits for asthma exacerbations.

PRACTICE IMPLICATIONS.  Patients may benefit from microsystem structures intentionally designed to facilitate implementation of evidence‐based guidelines.
The Real Reasons Enron Failed
Authors: Stewart Bennett
Published: June 2006

Why did Enron fail? Was it the criminality of key corporate executives, and their resort to deceptive bookkeeping and off‐balance sheet financing, as the popular accounts suggest?

This article argues that the popular accounts may confuse causes and consequences and suggests that the seeds of Enron's demise were sown years before criminal behavior took root. The more fundamental causes appear to have been matters of organizational design—in particular, bonus plans that paid managers to increase reported earnings; the use of mark‐to‐market accounting, with the blessing of the SEC, in generating those earnings; and CEO Skilling's decision to permit CFO Fastow to make finance a “profit center”—all of which happened five to ten years before Enron's bankruptcy filing.

In desperate attempts to keep up with aggressive earnings targets, Enron's managers became so indiscriminate in committing the firm's capital that, in 1999, the international energy division presented Skilling with a plan that contemplated earning just $100 million in profit on a capital base of $7 billion. With that kind of performance—which amounts to a loss of several hundred million in terms of economic profits—the CFO faced considerable pressure to use deceptive tactics to put off the day of reckoning. The real Enron story may thus be more than the morality play told in press accounts. A major part of the blame must be assigned to the design of the company's performance measures and internal controls.
California's Proposition 69: A Dangerous Precedent for Criminal DNA Databases
Authors: Simoncelli Tania , Steinhardt Barry
Published: June 2006

On November 2, 2004, California voters approved Proposition 69, “The DNA Fingerprint, Unsolved Crime, and Innocence Protection Act” by a margin of approximately 60 to 40 percent. Given the limited amount of information provided to voters during the initiative process, it is unclear how many of the yea-sayers were apprised of the full implications of this measure. Indeed, by voting “yes” on Proposition 69, California has elected to house the most radical and costly state criminal DNA database in the country. This dangerous expansion of California's database poses tremendous threats to civil liberties and social justice while offering little, if anything, by way of increasing the safety of its citizens.

Prior to November 2, California law required the permanent retention of DNA samples from felons convicted of serious, violent crimes.
Currents in Contemporary Ethics: Informed Trust and the Financing of Biomedical Research
Authors: Sharp Richard R. , Yarborough Mark
Published: June 2006

Academic medical centers and drug manufacturers have traditionally occupied very distinct positions with regard to public trust. As collaborations among medical researchers and pharmaceutical companies expand, however, worries about the aggressive pursuit of profit that has tarnished the reputation of the pharmaceutical industry may be transferred to medical institutions and clinical investigators, suggesting to some that biomedical research is more about increasing profit than promoting public health. Consequently, when medical institutions forge research collaborations with industry they should be mindful of the potential for these relationships to erode public confidence in the integrity of clinical research.

Recent events have heightened concerns about the financing of clinical research. These include the widely publicized deaths of several research volunteers, scandals at the nation's largest funder of biomedical research, and evidence of fabricated research findings in prominent medical journals. These unfortunate events have prompted many to re-examine strategies for managing industry relationships and the financial conflicts of interest they may create.
Differential effect of troponin T mutations on the inotropic responsiveness of mouse hearts – role of myofilament Ca2+ sensitivity increase
Authors: Sirenko Syevda G. , Potter James D. , Knollmann Björn C.
Published: June 2006

Troponin T (TnT) mutations that cause familial hypertrophic cardiomyopathy (FHC) and sudden cardiac death frequently increase myofilament Ca2+ sensitivity, suggesting that their Ca2+‐sensitizing effect contributes importantly to the FHC pathogenesis. To test this hypothesis, we compared transgenic mice expressing the Ca2+‐sensitizing TnT‐I79N mutant (I79N), which causes a high rate of sudden cardiac death in patients, with mice expressing the more benign TnT‐R278C mutant (R278C) that does not affect myofilament Ca2+ sensitivity. Acutely increasing myofilament Ca2+ sensitivity with EMD57033 served as a positive control. Isovolumically contracting hearts were compared over a range of loading conditions (Frank‐Starling curve). Consistent with their increased myofilament Ca2+ sensitivity, I79N‐Tg hearts demonstrated significantly higher systolic performance at low perfusate [Ca2+] compared with R278C‐Tg hearts, which were not statistically different from control hearts expressing either human wild‐type TnT or no transgene (CON). Diastolic function was impaired in both FHC mutants (time to 90% relaxation: I79N 48 ± 1.0 ms, n= 10 or R278C 47 ± 0.4 ms, n= 7, versus CON 44 ± 1.0 ms, n= 20, P < 0.05). In the presence of isoproterenol, almost all contractile parameters of R278C hearts became indistinguishable from control hearts, whereas both systolic and diastolic function of I79N hearts significantly worsened (end‐diastolic pressure: I79N 20 ± 4 mmHg versus CON 13 ± 2 mmHg or R278C 11 ± 2 mmHg, P < 0.05). The Ca2+ sensitizer EMD57033 produced an even greater contractile dysfunction than the I79N mutation at fast pacing rates. In vivo, maximal exercise tolerance was significantly impaired only in I79N mice. Pretreatment with β‐adrenergic receptor antagonists abolished differences in exercise tolerance. In conclusion, the Ca2+‐sensitizing effects of TnT mutations may reduce the responsiveness of mouse hearts to inotropic stimuli.
Angiotensin II regulates neuronal excitability via phosphatidylinositol 4,5‐bisphosphate‐dependent modulation of Kv7 (M‐type) K+channels
Authors: Zaika Oleg , Lara Lucienne S. , Gamper Nikita , Hilgemann Donald W. , Jaffe David B. , Shapiro Mark S.
Published: June 2006

Voltage‐gated Kv7 (KCNQ) channels underlie important K+currents in many different types of cells, including the neuronal M current, which is thought to be modulated by muscarinic stimulation via depletion of membrane phosphatidylinositol 4,5‐bisphosphate (PIP2). We studied the role of modulation by angiotensin II (angioII) of M current in controlling discharge properties of superior cervical ganglion (SCG) sympathetic neurons and the mechanism of action of angioII on cloned Kv7 channels in a heterologous expression system. In SCG neurons, which endogenously express angioII AT1 receptors, application of angioII for 2 min produced an increase in neuronal excitability and a decrease in spike‐frequency adaptation that partially returned to control values after 10 min of angioII exposure. The increase in excitability could be simulated in a computational model by varying only the amount of M current. Using Chinese hamster ovary (CHO) cells expressing cloned Kv7.2 + 7.3 heteromultimers and AT1 receptors studied under perforated patch clamp, angioII induced a strong suppression of the Kv7.2/7.3 current that returned to near baseline within 10 min of stimulation. The suppression was blocked by the phospholipase C inhibitor edelfosine. Under whole‐cell clamp, angioII moderately suppressed the Kv7.2/7.3 current whether or not intracellular Ca2+was clamped or Ca2+stores depleted. Co‐expression of PI(4)5‐kinase in these cells sharply reduced angioII inhibition, but did not augment current amplitudes, whereas co‐expression of a PIP25′‐phosphatase sharply reduced current amplitudes, and also blunted the inhibition. The rebound of the current seen in perforated‐patch recordings was blocked by the PI4‐kinase inhibitor, wortmannin (50 μm), suggesting that PIP2re‐synthesis is required for current recovery. High‐performance liquid chromatographic analysis of anionic phospholipids in CHO cells stably expressing AT1 receptors revealed that PIP2and phosphatidylinositol 4‐phosphate levels are to be strongly depleted after 2 min of stimulation with angioII, with a partial rebound after 10 min. The results of this study establish how angioII modulates M channels, which in turn affects the integrative properties of SCG neurons.
Experimental Response of Simple Gas Hybrid Bearings for Oil-Free Turbomachinery
Authors: Osborne Deborah A. , San Andre´s Luis
Published: June 2006

Gas film bearings offer unique advantages enabling successful deployment of high-speed microturbomachinery (<0.4 MW). Current applications encompass micropower generators, air cycle machines and turbo expanders. Mechanically complex gas foil bearings are in use; however, their excessive cost and lack of calibrated predictive tools deters their application to mass-produced systems. The present investigation provides experimental results for the rotordynamic performance of a small rotor supported on simple and inexpensive hybrid gas bearings with static and dynamic force characteristics desirable in high-speed turbomachinery. These characteristics are adequate load support, stiffness and damping coefficients, low friction and wear during rotor startup and shutdown, and most importantly, enhanced rotordynamic stability. The test results evidence the paramount effect of feed pressure on early rotor lift-off and substantially higher threshold speeds of rotordynamic instability. Higher supply pressures also determine larger bearing direct stiffnesses, and thus bring an increase in the rotor-bearing system critical speed albeit with a reduction in damping ratio.
A High-Pressure Droplet Model for Spray Simulations
Authors: Yan Changlin , Aggarwal Suresh K.
Published: June 2006

Droplet vaporization models that are currently employed in simulating sprays are based on a quasisteady, low-pressure formulation. These models do not adequately represent many high-pressure effects, such as nonideal gas behavior, solubility of gases into liquid, pressure dependence of gas- and liquid-phase thermophysical properties, and transient liquid transport in the droplet interior. In the present study, a high-pressure quasisteady droplet vaporization model is developed for use in comprehensive spray simulations for which more rigorous vaporization models, such as those based on unsteady formulations, are beyond the present computational capabilities. Except for the gas-phase quasisteady assumption that is retained in the model, the model incorporates all high-pressure effects. The applicability of the model for predicting droplet vaporization in diesel and gas turbine combustion environments is evaluated by comparing its predictions with the available experimental data and with those from a more comprehensive transient model. Results indicate a fairly good agreement between the quasisteady (QS) and transient (TS) models for a wide range of pressures at low ambient temperatures, and for pressure up to the fuel critical pressure at high ambient temperatures. The QS model generally underpredicts the vaporization rate during the earlier part of droplet lifetime and overpredicts during the later part of lifetime compared to those using the TS model, and the difference becomes increasingly more significant at higher ambient pressure and temperature. The differences can be attributed to the quasisteady gas-phase average temperature and composition assumption for the QS model that reduces and increases the gas-phase heat and mass fluxes at the droplet surface during the earlier and later part of lifetime, respectively. The applicability of the QS model is quantified in terms of the maximum pressure as a function of ambient temperature.
Active Rotor-Blade Vibration Control Using Shaft-Based Electromagnetic Actuation
Authors: Christensen René H. , Santos Ilmar F.
Published: June 2006

In this paper the feasibility of actively suppressing rotor and blade vibration via shaft-based actuation is studied. A mathematical model is derived, taking into account the special dynamical characteristics of coupled rotor-blade systems, such as centrifugal stiffened blades and parametric vibration modes. An investigation of controllability and observability shows that if the blades are properly mistuned, it is possible to suppress shaft as well as blade vibration levels by using only shaft-based actuation and sensing; though, in tuned bladed systems, shaft as well as blade actuation and sensing are required. In order to cope with the time-variant dynamics of the coupled rotor-blade system, a periodic time-variant modal controller is designed, implemented, and experimentally tested. A test rig built by four flexible blades is specially designed for this purpose. The rig is equipped with six electromagnetic actuators and different types of sensors (eddy-current displacement transducers, acceleration transducers, and strain gages) with the aim of monitoring and controlling shaft and blade vibration levels. Two different actively controlled rotor-blade system configurations are considered in the present study: (i) a tuned bladed rotor, controlled with help of actuators attached to the rotating blades and shaft-based actuators; (ii) a deliberately mistuned bladed rotor controlled only via shaft-based actuation. Experimental tests are carried out for both configurations. Some experimental problems regarding control implementation are identified and discussed, especially when the controller order and the number of actuators in the centralized control scheme become too high; though, for the mistuned bladed rotor controlled by using only shaft-based actuation, the controller works well.
Unbalance Response of Rotors Supported on Hydrodynamic Bearings Placed Close to Nodal Points of Excited Vibration Modes
Authors: Zachariadis Demetrio C.
Published: June 2006

The traditional 8-coefficient bearing model, used in linear rotor dynamics, is shown here to be inadequate for the unbalance response calculation of rotor systems supported on hydrodynamic journal bearings placed close to nodal points of excited modes of vibration. In such situations, one cannot neglect the time varying tilt angle between journals and bearings, whose consideration leads to the adoption of a 32-coefficient bearing model. Numerical results indicate that the differences between vibration amplitudes calculated using both bearing models can be greater than 100%, while discrepancies in the predicted stability thresholds are small. The conclusions of the study are coherent with previously published theoretical and experimental results.
Reduction of Nitric Oxides and Soot by Premixed Fuel in Partial HCCI Engine
Authors: Kim Dae Sik , Kim Myung Yoon , Lee Chang Sik
Published: June 2006

In order to obtain the reduction effect of NOx and soot emission in a partial homogeneous charge compression ignition engine, premixed fuel was supplied with direct injection diesel fuel. Several additional systems such as a premixed fuel injection system, exhaust gas recirculation (EGR) system, supercharger, and air heating system were equipped in the intake manifold of conventional diesel engine. Premixed fuel with air was compressed and ignited by the directly injected diesel fuel in the combustion chamber at the end of compression stroke. The effect of premixed fuel on combustion and emission characteristics of HCCI diesel engine was investigated experimentally under various conditions of intake air temperature, pressure, and EGR rate. The results showed that in case of the use of gasoline as a premixed fuel, single stage ignition is found, but premixing the diesel fuel accompanies the cool flame prior to the combustion of the directly injected diesel fuel. For the gasoline premixed fuel, both NOx and soot can be reduced by the increase of premixed ratio simultaneously. However, for the diesel premixed fuel, the increase of premixed ratio does not have a significant effect in reducing the soot emission.
Injection Pressure Fluctuations Model Applied to a Multidimensional Code for Diesel Engines Simulation
Authors: Ubertini Stefano
Published: June 2006

This paper deals with the pressure supply fluctuations that occur in the fuel rail and in the injector on the immediate upstream side of the atomizer. It has been experimentally demonstrated that this has a considerable effect on the instantaneous mass flow and spray velocity thus affecting the spray hard-core structure and the atomization process. Moreover, considering the oscillatory nature of the phenomenon, the effects on a given spray can change from one injection to the other (in modern multijet systems) and from one engine cycle to the next. The needed computing time and the uncertainty related to a detailed simulation of the injection system fluid dynamics would be unacceptable in a multidimensional computational code. Therefore a simplified model able to predict fuel pressure supply fluctuations on the upstream side of the injector has been developed and is described in this paper. The model is validated and calibrated by comparing numerical results with available experimental data. Some numerical results on a fuel spray injected into a vessel at constant pressure are finally presented, in order to quantify the impact of a given level of pressure fluctuations on fuel spray characteristics.
Remaining Life Prediction of Thermal Barrier Coatings Based on Photoluminescence Piezospectroscopy Measurements
Authors: Wen Mei , Jordan Eric H. , Gell Maurice
Published: June 2006

Nondestructive determination of the remaining life of thermal barrier coatings (TBCs) is highly desirable for components removed from service engines. Remaining life predictions for EB-PVD/Pt-Al TBCs cycled at two temperatures (1151°C and 1121°C) were made based on the thermally grown oxide stresses measured by the photoluminescence piezospectroscopy technique without knowing the test temperature. The predictions were compared using regression methods and neural network methods. It was found that both methods produce accurate life remaining predictions, but the neural network methods were superior. The lowest root-mean-square (rms) error and maximum absolute error for the prediction was 6.1% and 8.2%, respectively. For a data set with a 48.7% rms spallation life variation about the mean, the prediction results obtained are highly encouraging.
A Study on Transient Performance Characteristics of the Canard Rotor Wing Type Unmanned Aerial Vehicle Propulsion System During Flight Mode Transition
Authors: Kong Changduk , Park Jongha , Kang Myoungcheol
Published: June 2006

A propulsion system of the CRW (Canard rotor wing) type UAV (unmanned aerial vehicle) was composed of the turbojet engine, exhaust nozzles (including some tip jet nozzles and a main nozzle), and the duct system (including straight ducts, curved ducts, and master valve). The CRW-type UAV has three different flight modes, such as the rotary wing mode for takeoff and landing, the high-speed forward flight mode with the fixed wing, and the transition flight mode between the previously mentioned two flight modes. In order to evaluate transient performance characteristics of the CRW-type UAV propulsion system during flight mode transition, the propulsion system was modeled using SIMULINK®, which is a user-friendly graphical-user-interface-(GUI) type dynamic analysis tool provided by MATLAB, in this study. The transition flight mode between the rotary wing mode and the fixed wing mode was simulated by considering area variation of the master valve and the main exhaust nozzle. In order to verify acceptability of the main turbojet engine model, performance simulation results using SIMULINK were compared to results using the commercial program GSP. Through this simulation, proper operation of the master valve and the variable area main nozzle can be found for safe flight transition. Therefore, performance characteristics were investigated depending on various angle positions of the master valve.
Modeling and Identification of Hysteresis in Piezoelectric Actuators
Authors: Yeh T.-J. , Lu Shin-Wen , Wu Ting-Ying
Published: June 2006

In this paper, a model and the associated identification procedure are proposed to precisely portray the hysteresis behavior in piezoelectric actuators. The model consists of basic physical elements and utilizes a Maxwell-slip structure to describe hysteresis. By analyzing the model, the influence of initial strain/charges on the hysteresis behavior is revealed. It is also found that if all the spring elements in the model are linear, the resultant hysteresis loop is anti-symmetric and does not match the experimental behavior. To account for this mismatch, a nonlinear spring element is included into the model. The constitutive relation of the nonlinear spring and the parameters of the basic elements in the model are identified from experimental data by linear programming. Simulations of the identified model indicate that the model can reproduce the major as well as the minor hysteresis loops. An inverse control is further implemented to validate the accuracy of the identified model. Experiments show that hysteresis is effectively canceled and accurate tracking of a reference trajectory is achieved.
Robustness Limitations in Self-Sensing Magnetic Bearings
Authors: Maslen Eric H. , Montie Dominick T. , Iwasaki Tetsuya
Published: June 2006

Self-sensing magnetic bearings use measurements of voltage and current in electromagnets to estimate the position of a magnetically levitated object. By estimating position in this manner, explicit proximity sensors are eliminated, along with significant cost, weight, and hardware complexity. Motivated by early and discouraging experimental studies, several theoretical papers have concluded an inherent difficulty in employing self-sensing. In light of later experimental work that appears to avoid this difficulty, we argue that these conclusions may be attributed to an over-simplification in the model from which this apparent difficulty is inferred. Specifically, if a linear time-invariant (LTI) model is derived from the underlying nonlinear model by linearizing the system at a fixed equilibrium point, analysis of this LTI model leads to the incorrect conclusion that self-sensing cannot be robust. The present work establishes that, if essential features of the nonlinearity are retained by linearization along a periodic trajectory, analysis of the resulting linear periodic model predicts more acceptable levels of robustness.
Modeling and Analysis of Automatic Transmission Engagement Dynamics-Linear Case
Authors: Deur Joško , Asgari Jahan , Hrovat Davor , Kovač Petar
Published: June 2006

A control-oriented model of a typical four-speed automatic transmission is developed by using the bond graph modeling method. The planetary gear set model utilizes the Karnopp friction model for hydraulic and one-way clutches, in order to provide a favorable computing efficiency. The full gear set model is reduced for various phases of the park/reverse and park/drive engagements. The reduced gear set models and linearized torque converter model are used as a basis for an algebraic analysis of the engagement dynamics. The analysis is originally conducted for the basic case of fully applied brake, and it is then extended by an analysis of the influence of wheel dynamics in the brake-off case. The analysis results are verified by computer simulations and experiments.
Experimental Verification of Real-Time Control for Flexible Systems With On-Off Actuators
Authors: Singhose William , Biediger Erika , Okada Hideto , Matunaga Saburo
Published: June 2006

A technique for driving a flexible system with on-off actuators is presented and experimentally verified. The control system is designed to move the rigid body of a structure a desired distance without causing residual vibration in the flexible modes. The on-off control actions are described by closed-form functions of the system’s natural frequency, damping ratio, actuator force-to-mass ratio, and the desired move distance. Given the closed-form equations, the control sequence can be determined in real time without the need for numerical optimization. Performance measures of the proposed controller such as speed of response, actuator effort, peak transient deflection, and robustness to modeling errors are examined. Experiments performed on a flexible satellite testbed verify the utility of the proposed method.
Identification of Contact Dynamics Model Parameters From Constrained Robotic Operations
Authors: Weber M. , Patel K. , Ma O. , Sharf I.
Published: June 2006

With the fast advances in computing technology, contact dynamics simulations are playing a more important role in the design, verification, and operation support of space systems. The validity of computer simulation depends not only on the underlying mathematical models but also on the model parameters. This paper describes a novel strategy of identifying contact dynamics parameters based on the sensor data collected from a robot performing contact tasks. Unlike existing identification algorithms, this methodology is applicable to complex contact geometries where contact between mating objects occurs at multiple surface areas in a time-variant fashion. At the same time, the procedure requires only measurements of end-effector forces/moments and the kinematics information for the end-effector and the environment. Similarly to other methods, the solution is formulated as a linear identification problem, which can be solved with standard numerical techniques for overdetermined systems. Efficacy, precision, and sensitivity of the identification methodology are investigated in simulation with two examples: A cube sliding in a wedge and a payload/fixture combination modeled after a real space-manipulator task.
Dynamics of a Basketball Rolling Around the Rim
Authors: Liu C. Q. , Li Fang , Huston R. L.
Published: June 2006

Governing dynamical equations of motion for a basketball rolling on the rim of a basket are developed and presented. These equations form a system of five first-order, ordinary differential equations. Given suitable initial conditions, these equations are readily integrated numerically. The results of these integrations predict the success (into the basket) or failure (off the outside of the rim) of the basketball shot. A series of examples are presented. The examples show that minor changes in the initial conditions can produce major changes in the subsequent ball motion. Shooting and coaching strategies are recommended.
Localization and Quantification of Breathing Crack
Authors: Musil Milos
Published: June 2006

The possibility of localizing and quantifying a crack in a vibrating structure based on measured vibration amplitudes of the first and second harmonic in some locations of the structure and utilizing the mathematical model of an undamaged system, will be the focus of this paper. The structure is modeled by means of the finite element method. The effect of the breathing crack is modeled by the nonlinear (bilinear) stiffness of the element with the crack. The excitation of the system is characterized by the simultaneous effect of static and dynamic harmonic load. The Fourier series representations of the approximate analytical solution of a weakly bilinear system was used to obtain the localization and quanification a weak bilinearity. The method was documented on an elementary example, in which simulated measured data were determined by the use of the numerical solution of the nonlinear analytical model of a structure with a crack.
Delay-Dependent γ-Suboptimal H∞ Model Reduction for Neutral Systems With Time-Varying Delays
Authors: Wang Qing , Lam James , Xu Shengyuan , Zhang Liqian
Published: June 2006

In this paper, the model reduction problem of neutral systems with time-varying delays is studied with γ suboptimality under the H∞ measure. A delay-dependent bounded realness condition of the H∞ norm is given via linear matrix inequalities (LMIs). Based on such a condition, a sufficient condition to characterize the existence of the reduced-order models is given in terms of LMIs with inverse constraints. By employing a sequential convex optimization approach, a reduced-order model can be computed with H∞ error less than some prescribed scalar γ.
A Reliable Algorithm to Compute the Spectral Set of a Polytope of Polynomials to Prescribed Accuracy
Authors: Paluri Nataraj S. V. , Barve Jayesh J.
Published: June 2006

We propose an algorithm to compute the spectral set of a polytope of polynomials. The proposed algorithm offers several key guarantees that are not available with existing techniques. It guarantees that the generated spectral set: (i) contains all the actual points, (ii) is computed to a prescribed accuracy, (iii) is computed reliably in face of all kinds of computational errors, and (iv) is computed in a finite number of algorithmic iterations. A further merit is that the computational complexity of the proposed algorithm is O(n) in contrast to O(n2) for existing techniques, where n is the degree of the polynomial. The algorithm is demonstrated on a few examples.
A Sensor Placement Strategy for the Hybrid Adaptive Feedforward Observer
Authors: Tran Chau M. , Southward Steve C.
Published: June 2006

A sensor placement technique is proposed for implementing the hybrid adaptive feedforward observer. The observer is a conventional dynamic observer augmented with an adaptive feedforward component for estimating the effect of persistent, nonstationary disturbances. The placement technique searches for the least possible number of sensors that satisfy two criteria, the observability of the plant, and the lowest condition number of the error dynamic system's state matrix. Demonstration was performed on a one-dimensional acoustic duct. The results show that the proposed technique is an effective guideline for identifying the optimal sensor locations.
A Theoretical Control Strategy for a Diesel Engine
Authors: Outbib R. , Dovifaaz X. , Rachid A. , Ouladsine M.
Published: June 2006

In this paper we present a theoretical strategy for diesel engine control. More precisely, we propose a new approach to control the speed of the engine using the fuel rate as the control law and we show how this approach can be used to control the opacity. We first establish a mathematical model that describes the behavior of the engine. Afterward, we propose a new nonlinear method to design a controller for a class of nonlinear systems. The proposed method, based on Lyapunov theory, is used to design a smooth feedback law that renders the closed-loop system asymptotically stable around a desired engine speed value. Finally, simulation results are proposed to highlight the performances of the closed-loop system.
Kinematic Analysis and Design of a New 3-DOF Translational Parallel Manipulator
Authors: Li Yangmin , Xu Qingsong
Published: June 2006

A new three degrees of freedom (3-DOF) translational parallel manipulator (TPM) with fixed actuators called a 3-PRC TPM is proposed in this paper. The mobility of the manipulator is analyzed via screw theory. The inverse kinematics, forward kinematics, and velocity analysis are performed and the singular and isotropic configurations are identified afterward. Moreover, the mechanism design to eliminate all singularities and generate an isotropic manipulator has been presented. With the variation on architectural parameters, the reachable workspace of the manipulator is generated and compared. Especially, it is illustrated that the manipulator in principle possesses a uniform workspace with a constant hexagon shape cross section. Furthermore, the dexterity characteristics are investigated in the local and global sense, respectively, and some considerations for real machine design have been proposed as well.
Automatic Loop Shaping of MIMO Controllers Satisfying Sensitivity Specifications
Authors: Yaniv O.
Published: June 2006

An existing automatic loop shaping algorithm for designing SISO controllers is extended to automatic loop shaping of MIMO controllers that is based on the sequential QFT method. The algorithm is efficient and fast and can search for controllers satisfying many types of restrictions, including constraints on each one of the controller’s elements such as hard restrictions on the high-frequency amplitude or damping factor of notch filters. Moreover, the algorithm can be applied to unstructured uncertain plants, be they stable, unstable, or nonminimum phase, including pure delay.
Monotonicity and Active Set Strategies in Probabilistic Design Optimization
Authors: Chan Kuei-Yuan , Skerlos Steven , Papalambros Panos Y.
Published: June 2006

Probabilistic design optimization addresses the presence of uncertainty in design problems. Extensive studies on reliability-based design optimization, i.e., problems with random variables and probabilistic constraints, have focused on improving computational efficiency of estimating values for the probabilistic functions. In the presence of many probabilistic inequality constraints, computational costs can be reduced if probabilistic values are computed only for constraints that are known to be active or likely active. This article presents an extension of monotonicity analysis concepts from deterministic problems to probabilistic ones, based on the fact that several probability metrics are monotonic transformations. These concepts can be used to construct active set strategies that reduce the computational cost associated with handling inequality constraints, similarly to the deterministic case. Such a strategy is presented as part of a sequential linear programming algorithm along with numerical examples.
NON-ABELIAN BORN–INFELD THEORY WITHOUT THE SQUARE-ROOT
Authors: OBREGÓN O.
Published: June 2006

A non-Abelian Born–Infeld theory is presented. Its construction does not require the square-root structure that characterizes the Dirac–Born–Infeld (DBI) action. The procedure is based on an Abelian theory proposed by Schrödinger that, as he showed, is equivalent to Born–Infeld theory. Various non-Abelian generalizations are possible. We focus our attention on one of them. For it, it is shown that instantons solutions exist. Our formalism could be of interest in connection with string theory and possible extensions of well-known physical results in the usual Born–Infeld Abelian case.
COUPLING CONSTANT ga0ωγAS DERIVED FROM LIGHT-CONE QCD SUM RULES
Authors: AYDIN C. , YILMAZ A. H.
Published: June 2006

We investigate the a0ωγ vertex and estimate the coupling constant ga0ωγin the framework of the light-cone QCD sum rules. We compare our result with the value of the coupling constant calculated in the QCD sum rules.
THEORETICAL INVESTIGATION OF PULSE SHAPES OF DOUBLE BETA EVENTS IN A 76Ge DETECTOR, THEIR DEPENDENCE ON PARTICLE PHYSICS PARAMETERS, AND THEIR SEPARABILITY FROM BACKGROUND GAMMA EVENTS
Authors: KLAPDOR-KLEINGROTHAUS H. V. , KRIVOSHEINA I. V. , TITKOVA I. V.
Published: June 2006

For the first time the expected pulse shapes to be observed for neutrinoless double beta events in a big 76 Ge detector have been calculated starting from their Monte Carlo calculated time history and spatial energy distribution. It is shown that with the spatial resolution of a large size Ge detector for the majority of 0νββ events it is not possible to differentiate between the contributions of different particle physics parameters entering into the 0νββ decay process — in the mass mechanism the effective neutrino mass and the right-handed weak current parameters λ, η. It is shown that on the other hand it is possible in a 76 Ge double beta decay experiment to reject a background of larger sizes (high multiplicity) gamma events by selecting low size (low multiplicity) events. First comparison of the theoretical ββ pulses to events from the line observed at3,4Qββ shows very good agreement. It is shown further that a rather good radial position determination of ββ events in the detector is possible. By the same type of calculation it is shown that use of the pulse shapes of the 1592 keV double escape line of the 2614 keV γ-transition from 228 Th for calibrating a neuronal net for search of events of neutrinoless double beta decay should be helpful.