bluuebunny/crossref_metadata_2025 huggingface dataset:
Qualitative research on the Belgian Cancer Rehabilitation Evaluation System (CARES): An evaluation of the content validity and feasibility
Authors: Schouten Bojoura , Hellings Johan , Vankrunkelsven Patrick , Mebis Jeroen , Bulens Paul , Buntinx Frank , Vandijck Dominique , Van Hoof Elke
Published: January 2017

Rationale, aims, and objectives

The systematic assessment of cancer patients well‐being and care needs is internationally recommended to optimize comprehensive cancer care. The Cancer Rehabilitation Evaluation System (CARES) is a psychometrically robust quality of life and needs assessment tool of US origin, developed in the early 1990s. This article describes Belgian patients' view on the content validity and feasibility of the CARES for use in current cancer care.

Methods

Participants were cancer patients recruited through media. Data were gathered in 4 focus groups (n = 26). The focus group discussions were facilitated with key questions. A moderator and an observer conducted and followed up the discussion. The audio file was transcribed verbatim and afterwards analyzed thematically.

Results

Participants experience concerns and needs in a wide range of life domains such as physical, emotional, cognitive, social, relational, sexual, financial, and work‐related and in the interaction with care professionals. According to participants, the items of the CARES are all relevant to capture the possible life disruption that cancer patients and survivors experience. One important theme is missing in the CARES, namely, the well‐being of loved ones. The completion time of the CARES was judged to be feasible, and according to participants, only a few items need a reformulation.

Conclusions

In general, the results of this study support the content validity and feasibility of the CARES. However, little adjustments in formulation and a few extra items are needed. The instrument can be used to obtain a comprehensive assessment of a cancer patients' overall well‐being and care needs to take dedicated action in care.
A Current Perspective on Screw‐Retained Single‐Implant Restorations: A Review of Pertinent Literature
Authors: Priest George
Published: January 2017

Objective

There is a trend toward increased use of screw‐retained single‐implant restorations. A comprehensive literature review was undertaken to examine the data related to screw‐ and cement‐retention and to objectively evaluate the innovations in implant dentistry that have led to this resurgence.

Overview

When comparing the two options, survival and complication rates are similar, bone and soft‐tissue levels are comparable, and zirconia offers esthetic advantages for both selections. Zirconia abutments with bonded titanium inserts provide esthetic alternatives to titanium abutments for both choices. Bone‐ and soft‐tissue responses are similar, but residual cement of cement‐retained restorations is associated with significant soft‐ and hard‐tissue complications. The potential weakness of ceramic discontinuity of screw‐access openings can be lessened by the incorporation of stronger ceramic materials such as zirconia and lithium disilicate. The overriding remaining indication for cement‐retained restorations is to compensate for angled implants.

Conclusions

Screw‐retained single‐implant crowns should be reconsidered for many clinical situations for the following reasons:

Predictable retention and retrievability

No potential for the biologic consequences associated with residual cement

As with cement‐retained restorations, the choice between metal ceramics or all ceramics

Only one margin, at the implant/abutment interface

A single abutment/crown ceramic margin that can extend gingivally to the implant interface

Nearly imperceptible blend of a composite resin in ceramic abutment access openings

One component instead of two, which may simplify the restorative process

CLINICAL SIGNIFICANCE

Innovations in implant and ceramic technology now give screw‐retained prostheses the potential for esthetic, functional, and biologic outcomes that are comparable to those for cement‐retained prostheses, while providing the advantages of predictable retrievability and avoidance of residual cement. Angled implants, however, remain a major indication for cement‐retained single‐implant prostheses. (J Esthet Restor Dent 29:161–171, 2017)
Patients in Haemodialysis Experienced Uraemic Pruritus as a Dual Phenomenon
Authors: Tarp Helene , Bonde‐Petersen Malene , Finderup Jeanette
Published: January 2017

Background

Uraemic pruritus (UP) is one of the most frequent symptoms for patients in haemodialysis. Studies show that UP decreases quality of life including sleep. Patients find it difficult to describe the symptoms of UP to healthcare professionals.

Objectives

To explore how patients in haemodialysis experience the phenomenon of UP.

Methods

A qualitative phenomenological‐hermeneutic framework was used. Fifteen semi‐structured interviews were undertaken at a Danish university hospital in November 2015. The interviews were transcribed and analysed using Malterud's principles of systematic text condensation.

Results

Patients gave conflicting descriptions of the phenomenon. Patients experienced UP as a dual phenomenon described as ‘the itch’ and ‘itching’. ‘The itch’ will never disappear and is unmanageable, and ‘itching’ appears intermittently and is possible to prevent and alleviate.

Conclusion/Application to practice

It is impossible for patients to manage UP on their own but it may be possible to manage it as a dual phenomenon. This knowledge can give both patients and healthcare professionals a new perspective on UP and its symptoms.
The Dynamics of Religious Practice in Spain from the Mid‐19th Century to 2010
Authors: Rossi Maurizio , Scappini Ettore
Published: January 2017

Like other Western countries, Spain is rapidly becoming more secularized. While there is almost unanimous agreement that this is happening, significant discord exists about the phases of the process and the speed of its development. This is mostly due to the use of partial and sometimes unreliable data. The aim of this study is to remedy these uncertainties. Our work is based on the data provided by time‐use surveys conducted in 2003 and 2010. Using some basic provisional but reasonable assumptions, we demonstrate that it is possible to identify a plausible dynamic of secularization in Spain starting in the second half of the 19th century. We also highlight the fact that the different indicators feature some significant time lags. Indeed, the dating of the start of the secularization process varies depending on whether reference is made to data on birth cohorts, the overall population, or the “visibility” of the phenomenon.
Profile and outcome of first 109 cases of paediatric acute liver failure at a specialized paediatric liver unit in India
Authors: Alam Seema , Khanna Rajeev , Sood Vikrant , Lal Bikrant B. , Rawat Dinesh
Published: January 2017

Background & Aims

The outcome of paediatric acute liver failure largely depends on age and aetiology. The aim of this work was to study the aetiological spectrum and outcome of the paediatric acute liver failure cases.

Methods

This prospective observational study included all children (<18 years age) fulfilling paediatric acute liver failure study group definition. Aetiological evaluation was done and predictive factors for poor outcome (death or liver transplantation) were analysed.

Results

There were 109 children in total. The commonest aetiology was viral infections (50, 45.8%) followed by metabolic liver diseases (14, 13.2%) and drug‐induced liver injury (12, 11%). Viral, indeterminate and drug‐induced liver injury group were older in age, had higher international normalized ratio and alanine transaminases in comparison with those with metabolic liver diseases and other aetiologies (P<.05). At 90 days from presentation, 52 (47.7%) children survived with native liver. On multivariate analysis, jaundice to encephalopathy interval >7 days (adjusted OR: 9.16, 95% CI: 1.55‐53) and higher paediatric/model for end‐stage liver disease scores at 72 hours (adjusted OR: 1.2, 95% CI: 1.08‐1.32) were associated with poor outcome.

Conclusion

Viral infections, indeterminate and drug‐induced liver injury‐related paediatric acute liver failure usually present in older children with higher international normalized ratio and alanine transaminases. Jaundice to encephalopathy interval >7 days and paediatric/model for end stage liver disease score >24 at 72 hours are associated with poor outcome.
Mortality from cirrhosis and hepatocellular carcinoma in Western Europe over the last 40 years
Authors: Ascione Antonio , Fontanella Luca , Imparato Michele , Rinaldi Luca , De Luca Massimo
Published: January 2017

Background & Aims

Cirrhosis (LC) and hepatocellular carcinoma (HCC) are highly prevalent in Europe, with accompanying high mortality rates and social costs. As epidemiological data on these diseases are scarce, age‐standardized death rate (ASDR) can serve as an indirect assessment of their burden.

Methods

We analysed the ASDRs for LC and HCC from data reported in the WHO official death registries from 1970 to 2010, and compared ASDRs over the decades. The European Detailed Mortality Database was also used as source of data.

Results

In 1970, Portugal had the highest reported mortality for LC, followed by France and Italy. However, in 2010, Finland, Austria and Germany were respectively the three highest, while the UK showed the highest increase over those four decades (+284.8%). The annual ASDRs for LC have dropped in Europe from 20.4/105 inhabitants in 1970 to 9.6 in 2010; a 53% decrease. For HCC, Spain, Italy and Denmark were ranked first through third, while in 2010 Italy, France and Luxembourg replaced them. Portugal had the highest increase (+654.7%). In 1980‐2010, the ASDR for HCC in Europe increased from 3.4/105 inhabitants to 6.3, up 85.4%. In the majority of nations—except for the UK, Finland and Ireland—there was a decrease in LC mortality and an increase for HCC mortality.

Conclusions

The LC mortality rate is decreasing in Europe, yet there is a significant increase in HCC mortality. This phenomenon requires greater attention so we can understand the risk factors and implement preventive measures.
Expressive Law, Social Norms, and Social Groups
Authors: Nadler Janice
Published: January 2017

To understand how law works outside of sanctions or direct coercion, we must first appreciate that law does not generally influence individual behavior in a vacuum, devoid of social context. Instead, the way in which people interact with law is usually mediated by group life. In contrast to the instrumental view that assumes law operates on autonomous individuals by providing a set of incentives, the social groups view holds that a person's attitude and behavior regarding any given demand of law are generally products of the interaction of law, social influence, and motivational goals that are shaped by that person's commitments to specific in-groups. Law can work expressively, not so much by shaping independent individual attitudes as by shaping group values and norms, which in turn influence individual attitudes. In short, the way in which people interact with law is mediated by group life.
Antihyperalgesic, Antiallodynic, and Antinociceptive Effects of Cebranopadol, a Novel Potent Nociceptin/Orphanin FQ and Opioid Receptor Agonist, after Peripheral and Central Administration in Rodent Models of Neuropathic Pain
Authors: Tzschentke Thomas M. , Linz Klaus , Frosch Stefanie , Christoph Thomas
Published: January 2017

Cebranopadol is a novel and highly potent analgesic acting via nociceptin/orphanin FQ peptide (NOP) and opioid receptors. Since NOP and opioid receptors are expressed in the central nervous system as well as in the periphery, this study addressed the question of where cebranopadol exerts its effects in animal models of chronic neuropathic pain. Mechanical hypersensitivity in streptozotocin (STZ)‐treated diabetic rats, cold allodynia in the chronic constriction injury (CCI) model in rats, and heat hyperalgesia and nociception in STZ‐treated diabetic and control mice was determined after intraplantar (i.pl.), intracerebroventricular (i.c.v.), or intrathecal (i.th.) administration. In STZ‐treated rats, cebranopadol (i.pl.) reduced mechanical hypersensitivity in the ipsilateral paw, but had no effect at the contralateral paw. In CCI rats, cebranopadol (i.pl.) showed antiallodynic activity at the ipsilateral paw. After administration to the contralateral paw, cebranopadol also showed ipsilateral antiallodynic activity, but with reduced potency and delayed onset. In diabetic mice, cebranopadol i.th. and i.c.v. decreased heat hyperalgesia with full efficacy and similar potency for both routes. Cebranopadol also produced significant antinociception in nondiabetic controls. Thus, cebranopadol exerts potent and efficacious antihyperalgesic, antiallodynic, and antinociceptive effects after local/peripheral, spinal, and supraspinal administration. The contralateral effects after i.pl. administration were likely due to systemic redistribution. After central administration of cebranopadol, antihyperalgesic efficacy is reached at doses that are not yet antinociceptive. This study shows that cebranopadol is effective after peripheral as well as central administration in nociceptive and chronic neuropathic pain. Thus, it may be well‐suited for the treatment of chronic pain conditions with a neuropathic component.
Comparison of Salivary Cortisol and α‐amylase Levels and Psychological Profiles in Patients with Burning Mouth Syndrome
Authors: Nosratzehi Tahereh , Salimi Saeedeh , Parvaee Azadeh
Published: January 2017

Purpose

The aim of the study was to compare salivary cortisol and α‐amylase levels and psychological profiles in patients with burning mouth syndrome (BMS) and healthy subjects.

Methods and Materials

Spitting method was used to collect unstimulated salivary. Salivary cortisol and α‐amylase levels were determined using ELISA and the Caraway starch‐iodine technique. SLC‐90 questionnaire was used to determine the psychological profiles.

Results

The difference between mean of salivary cortisol levels in patients with BMS and in healthy subjects was not significant (4.50 ± 3.68 ng/mL vs. 3.69 ± 3.07 ng/mL, p = 0.377). The difference between mean of α‐amylase levels in the BMS patients and healthy subjects was significant (351.68 ± 142.5 and 146.22 ± 130.4, p = 0.001). Note that, 83.4% and 18% of the patients in the case and control groups had psychological problems (p = 0.001).

Conclusion

The results showed higher salivary levels of cortisol and α‐amylase in patients with BMS compared to healthy individuals. Psychological problem was prevalent in patients.
Orchestrating rapid long‐distance signaling in plants with Ca2+, ROS and electrical signals
Authors: Choi Won‐Gyu , Miller Gad , Wallace Ian , Harper Jeffrey , Mittler Ron , Gilroy Simon
Published: January 2017

Plants show a rapid systemic response to a wide range of environmental stresses, where the signals from the site of stimulus perception are transmitted to distal organs to elicit plant‐wide responses. A wide range of signaling molecules are trafficked through the plant, but a trio of potentially interacting messengers, reactive oxygen species (ROS), Ca2+ and electrical signaling (‘trio signaling’) appear to form a network supporting rapid signal transmission. The molecular components underlying this rapid communication are beginning to be identified, such as the ROS producing NAPDH oxidase RBOHD, the ion channel two pore channel 1 (TPC1), and glutamate receptor‐like channels GLR3.3 and GLR3.6. The plant cell wall presents a plant‐specific route for possible propagation of signals from cell to cell. However, the degree to which the cell wall limits information exchange between cells via transfer of small molecules through an extracellular route, or whether it provides an environment to facilitate transmission of regulators such as ROS or H+ remains to be determined. Similarly, the role of plasmodesmata as both conduits and gatekeepers for the propagation of rapid cell‐to‐cell signaling remains a key open question. Regardless of how signals move from cell to cell, they help prepare distant parts of the plant for impending challenges from specific biotic or abiotic stresses.
El proceso de construcción de normas sistémicas visto desde una epistemología genética neoconstructivista basada en Jean Piaget
Authors: Sánchez Mendioroz Ángel
Published: January 2017

Los procesos de globalización y de regionalización en el mundo exigen nuevas formas de regulación, las cuales deberán superar, coordinar y organizar las estructuras normativas institucionales actuales características de la modernidad. El presente trabajo es un ensayo epistemológico, basado en Jean Piaget, que propone la necesidad de ampliar las actuales estructuras normativas y pasar de un estadio institucional-moderno a un estadio sistémico-posmoderno. Esta pro-puesta está basada, primero, en la existencia de estadios sociocognitivos que determinan las características esenciales de toda estructura social de regulación. Segundo, en el surgimiento y en la construcción global de un nuevo estadio sociocognitivo de estructuras regulativas: el estadio constructivista-sistémico. Tercero, el enfoque predice el surgimiento de una nueva estructura estatal con carácter sistémico: el Estado internacional. Esta nueva estructura de gobernanza sistémica deberá poder surgir solo sobre la base de las estructuras institucionales de normación del actual Estado-nación. El análisis metodológico neopiagetiano —con carácter dialéctico— que expone este artículo pretende demostrar la tesis sociocognitiva mencionada.
Conocimientos en salud bucal de los cuidadores del Programa Buen Comienzo
Authors: González-Penagos Catalina , Cano-Gómez Melissa , Meneses-Gómez Edwin J. , Saldarriaga-Bolívar Verónica
Published: January 2017

Objetivo: analizar los conocimientos en salud bucal de los cuidadores del Programa Buen Comienzo, Fantasías de las Américas, 2015. Materiales y métodos: estudio cualitativo histórico-hermenéutico, la información se obtuvo a partir de la técnica interactiva descriptiva del mural de situaciones. Población conformada por 183 padres, madres y cuidadores de los Centros Infantiles Fantasías de las Américas. Se identificaron unidades de análisis y se crearon categorías y subcategorías, con el fin de reducir los datos y realizar la contrastación y la triangulación de la información. Resultados: se evidenció una pluralidad en las necesidades expresadas por los cuidadores en relación con la salud bucal y aspectos relacionados con su prevención y tratamiento. Se identificaron necesidades específicas relacionadas con patologías y condiciones asociadas a los hábitos, así como las alteraciones en la variabilidad de la salud bucal. Conclusiones: la identificación de las necesidades expresadas y sentidas por los cuidadores exige que se tengan en cuenta nuevas temáticas para enriquecer los saberes desde las actividades de educación y promoción de la salud. Se abre una mirada pluralista en la que todos participan, conocen, discuten y exigen calida
Hydrodynamic and Thermal Performance of Microchannels With Different Staggered Arrangements of Cylindrical Micro Pin Fins
Authors: Mohammadi Ali , Koşar Ali
Published: January 2017

This study focuses on microheat sinks with different staggered arrangements of micro pin fins (MPFs). A rectangular microchannel with the dimensions of 5000 × 1500 × 100 μm3 (l′ × w′ × h′) was considered for all the configurations while different MPF diameters, height over diameter ratio (H/D), and longitudinal and transversal pitch ratios (SL/D and ST/D) were considered in different arrangements. Using the ansys fluent 14.5 commercial software, the simulations were done for different Reynolds numbers between 20 and 160. A constant heat flux of 30 W/cm2 was applied through the bottom heating section. The performances of the microheat sinks were evaluated using design parameters, namely pressure drop, friction factor, Nusselt number, and thermal-hydraulic performance index (TPI). The effect of each geometrical parameter as well as wake-pin fin interaction patterns were carefully studied using the streamline patterns and temperature profiles of each configuration. The results reveal a great dependency of trends in pressure drops and Nusselt numbers on the wake region lengths as well as the local velocity and pressure gradients. Moreover, the wake region lengths mostly contribute to the increase in obtained pressure drop and Nusselt number with Reynolds number. Although an increase in the H/D and SL/D ratios results in an increase and a decrease in pressure drop, respectively, the effect on the Nusselt number depends on other geometrical parameters and Reynolds number. A larger ST/D ratio generally results in a decrease in the pressure drop and Nusselt number. Finally, while the friction factor decreases with Reynolds number, two different trends are seen for the TPI values of configurations with the H/D ratio of 1 and 2 (D = 100 and 50 μm). While the trend in the TPIs is increasing for Reynolds numbers between 20 and 40, it reverses for higher Reynolds numbers with a steeper slope in the configurations with the ST/D ratio of 1.5.
The Statistical Analysis of Droplet Train Splashing After Impinging on a Superheated Surface
Authors: Qiu Lu , Dubey Swapnil , Hoong Choo Fook , Duan Fei
Published: January 2017

An orderly droplet splashing is established when a water droplet train impinges onto a superheated copper surface. The droplets continuously impinge onto the surface with a rate of 40,000 Hz, a diameter of 96 μm or 120 μm, and a velocity of 8.4 m/s or 14.5 m/s. The heat transfers under different wall temperatures are measured, and the corresponding droplet splashing is recorded and analyzed. The effects of wall temperature, droplet Weber number, and surface roughness on the transition of the droplet splashing are investigated. The results suggest that the transferred energy is kept a constant in the transition regime, but a sudden drop of around 25% is observed when it steps into post-transition regime, indicating that the Leidenfrost point is reached. A higher Weber number of droplet train results in a more stable splashing angle and a wider range of splashed droplet diameter. The surface roughness plays no significant role in influencing the splashing angle in the high Weber number case, but the rougher surface elevates the fluctuation of the splashing angle in the low Weber number case. On the rougher surface, the temporary accumulation of the impact droplets is observed, a “huge” secondary droplet can be formed and released. The continuous generation of the huge droplets is observed at a higher wall temperature. Based on the result of droplet tracking of the splashed secondary droplets, the diameter and velocity are correlated.
Characterizing Flow Effects of Ported Shroud Casing Treatment on Centrifugal Compressor Performance
Authors: Christou George A. , Tan Choon S. , Sirakov Borislav T. , Lei Vai-Man , Alescio Giuseppe
Published: January 2017

This paper presents an investigation of the effects of ported shroud (PS) self-recirculating casing treatment used in turbocharger centrifugal compressors for increasing the operable range. The investigation consists of computing three-dimensional flow in a representative centrifugal compressor with and without PS at various levels of approximations in flow physics and geometrical configuration; this provides an enabler for establishing the causal link between PS flow effects and compressor performance changes. It is shown that the main flow path perceives the PS flow as a combination of flow actuations that include injection and removal of mass flow and injection of axial momentum and tangential momentum. A computational model in which the presence of the PS is replaced by imposed boundary conditions (BCs) that reflect the individual flow actuations has thus been formulated and implemented. The removal of a fraction of the inducer mass flow has been determined to be the dominant flow actuation in setting the performance of PS compressors. Mass flow removal reduces the flow blockage associated with the impeller tip leakage flow and increases the diffusion in the main flow path. Adding swirl to the injected flow in the direction opposite to the wheel rotation results in an increase of the stagnation pressure ratio and a decrease of the efficiency. The loss generation in the flow path has been defined to rationalize efficiency changes associated with PS compressor operation.
A New Extrapolation-Based Uncertainty Estimator for Computational Fluid Dynamics
Authors: Phillips Tyrone S. , Roy Christopher J.
Published: January 2017

A new Richardson extrapolation-based uncertainty estimator is developed which utilizes a global order of accuracy. The most significant difference between the proposed uncertainty estimator (referred to as the global deviation uncertainty estimator) and others in the literature is that we compute uncertainty estimates at all cells/nodes in the domain regardless of the local convergence behavior (i.e., even if the local solution is oscillatory with grid refinement). Various metrics are used to quantitatively calibrate and evaluate the uncertainty estimator compared to the true solution. The metrics are used to assess the global deviation uncertainty estimator compared to other commonly used uncertainty estimators of the same type such as the original grid convergence index (GCI) and the factor of safety method. Four two-dimensional, steady, inviscid flow fields with exact solutions are used to calibrate the parameters in the proposed uncertainty estimator and make up about 30% of the total solution data set. The evaluation data set is composed of several additional steady, two-dimensional and three-dimensional solutions computed using different computational fluid dynamics codes with exact solutions including a zero pressure gradient turbulent flat plate with a well-defined numerical benchmark. All solutions are formally first- or second-order accurate. The global deviation uncertainty estimator is developed using an empirical approach with a focus on local variables and shows significant improvement compared to existing extrapolation-based uncertainty estimates, even when applied to regions where the local convergence behavior is divergent or oscillatory.
Experimental Validation of a Nonlinear Model Calibration Method Based on Multiharmonic Frequency Responses
Authors: Chen Yousheng , Linderholt Andreas , Abrahamsson Thomas J. S.
Published: January 2017

Correlation and calibration using test data are natural ingredients in the process of validating computational models. Model calibration for the important subclass of nonlinear systems which consists of structures dominated by linear behavior with the presence of local nonlinear effects is studied in this work. The experimental validation of a nonlinear model calibration method is conducted using a replica of the École Centrale de Lyon (ECL) nonlinear benchmark test setup. The calibration method is based on the selection of uncertain model parameters and the data that form the calibration metric together with an efficient optimization routine. The parameterization is chosen so that the expected covariances of the parameter estimates are made small. To obtain informative data, the excitation force is designed to be multisinusoidal and the resulting steady-state multiharmonic frequency response data are measured. To shorten the optimization time, plausible starting seed candidates are selected using the Latin hypercube sampling method. The candidate parameter set giving the smallest deviation to the test data is used as a starting point for an iterative search for a calibration solution. The model calibration is conducted by minimizing the deviations between the measured steady-state multiharmonic frequency response data and the analytical counterparts that are calculated using the multiharmonic balance method. The resulting calibrated model's output corresponds well with the measured responses.
Adaptive Semi-Implicit Integrator for Articulated Mechanical Systems
Authors: Hewlett Joe , Kovacs Laszlo , Callejo Alfonso , Kry Paul G. , Kövecses József , Angeles Jorge
Published: January 2017

This paper concerns the dynamic simulation of constrained mechanical systems in the context of real-time applications and stable integrators. The goal is to adaptively find a balance between the stability of an over-damped implicit scheme and the energetic consistency of the symplectic, semi-implicit Euler scheme. As a starting point, we investigate in detail the properties of a recently proposed timestepping scheme, which approximates a full nonlinear implicit solution with a single linear system, without compromising stability. This scheme introduces a geometric stiffness term that improves numerical stability up to a certain time-step size, but it does so at the cost of large mechanical dissipation in comparison to the traditional constrained dynamics formulation. Dissipation is sometimes undesirable from a mechanical point of view, especially if the dissipation is not quantified. In this paper, we propose to use an additional control parameter to regulate “how implicit” the Jacobian matrix is, and change the degree to which the geometric stiffness term contributes. For the selection of this parameter, adaptive schemes are proposed based on the monitoring of energy drift. The proposed adaptive method is verified through the simulation of open-chain systems.
Reliability-Based Design Optimization Using Confidence-Based Model Validation for Insufficient Experimental Data
Authors: Moon Min-Yeong , Choi K. K. , Cho Hyunkyoo , Gaul Nicholas , Lamb David , Gorsich David
Published: January 2017

The conventional reliability-based design optimization (RBDO) methods assume that a simulation model is able to represent the real physics accurately. However, this assumption may not always hold as the simulation model could be biased. Accordingly, designed product based on the conventional RBDO optimum may either not satisfy the target reliability or be overly conservative design. Therefore, simulation model validation using output experimental data, which corrects model bias, should be integrated in the RBDO process. With particular focus on RBDO, the model validation needs to account for the uncertainty induced by insufficient experimental data as well as the inherent variability of the products. In this paper, a confidence-based model validation method that captures the variability and the uncertainty, and that corrects model bias at a user-specified target confidence level, has been developed. The developed model validation helps RBDO to obtain a conservative RBDO optimum design at the target confidence level. The RBDO with model validation may have a convergence issue because the feasible domain changes as the design moves (i.e., a moving-target problem). To resolve the issue, a practical optimization procedure is proposed. Furthermore, the efficiency is achieved by carrying out deterministic design optimization (DDO) and RBDO without model validation, followed by RBDO with confidence-based model validation. Finally, we demonstrate that the proposed RBDO approach can achieve a conservative and practical optimum design given a limited number of experimental data.
Thick Rigidly Foldable Origami Mechanisms Based on Synchronized Offset Rolling Contact Elements
Authors: Lang Robert J. , Nelson Todd , Magleby Spencer , Howell Larry
Published: January 2017

We present a general technique for achieving kinematic single degree of freedom (1DOF) origami-based mechanisms with thick rigid panels using synchronized offset rolling contact elements (SORCEs). We present general design analysis for planar and 3D relative motions between panels and show physically realized examples. The technique overcomes many of the limitations of previous approaches for thick rigidly foldable mechanisms.
Current Severe Accident Research and Development Topics for Wolsong PHWR Safety in Korea
Authors: Song Y. M. , Kim D. H. , Park S. Y. , Song J. H.
Published: January 2017

In Korea, pressurized heavy water-cooled reactors (PHWR) account for 17% of operating units and have taken an important role in providing national energy supply. The recent biggest issue in domestic PHWR community was the continued operation of the Wolsong-1 CANada Deuterium Uranium (CANDU) plant, which has recently been approved to operate for 10 more years after a 30 year design life. In relation to this issue, various actions from both post-Fukushima lessons and Wolsong-1 (WS1) stress test results are being taken. In KAERI R&D, the following topics are studied to support the basis for these actions. First, PHWR severe accident issues such as (1) primary heat transport system (PHTS) overpressure protection capability, (2) containment overpressure protection capability, and (3) bypass source term are evaluated. Second, a computer tool (called MAAP–ISAAC) has been modified and updated to support analyzing Wolsong severe accident issues. Third, a decision supporting tool, called Severe Accident Management Expert (SAMEX)–CANDU, has been developed to aid emergency response experts under severe accident conditions.
Effect of Condition Monitoring on Risk Mitigation for Steam Turbines in the Forest Products Industry
Authors: Zhou Bin , Bhimavarapu Kumar
Published: January 2017

Industry has been implementing condition monitoring (CM) for turbines to minimize losses and to improve productivity. Deficient conditions can be identified before losses occur by monitoring the equipment parameters. For any loss scenario, the effectiveness of monitoring depends on the stage of the loss scenario when the deficient condition is detected. A scenario-based semi-empirical methodology was developed to assess various types of condition monitoring techniques, by considering their effect on the risk associated with mechanical breakdown of steam turbines in the forest products (FPs) industry. A list of typical turbine loss scenarios was first generated by reviewing loss data and leveraging expert domain knowledge. Subsequently, condition monitoring techniques that can mitigate the risk associated with each loss scenario were identified. For each loss scenario, an event tree analysis (ETA) was used to quantitatively assess the variations in the outcomes due to condition monitoring, and resultant changes in the risk associated with turbine mechanical breakdown. An application was developed following the methodology to evaluate the effect of condition monitoring on turbine risk mitigation.
Response of Steel Fiber Reinforced Cementitious Composite Panels Subjected to Extreme Loading Conditions
Authors: Prakash Amar , Srinivasan S. M. , Rama Mohan Rao A.
Published: January 2017

Application of steel fiber reinforced cementitious composites (SFRCC) in the construction of protective structures against extreme loading conditions, such as high-velocity impact and blasts, is an active area of research. It is a challenging task to capture the material behavior under such harsh conditions where strain rate of loading exceeds beyond 104 s−1. In this paper, an effort is made to simulate numerically the multihits of short projectiles on SFRCC panels. A total of 90 numbers of SFRCC panels consist of various core layer materials, thicknesses, fiber volumes, and angle of obliquity, are tested under high-velocity impacts of short projectiles. In numerical simulations, the boundary conditions and impact loading sequence are maintained, similar to that used during impact tests. In order to carry out a realistic numerical simulation, in-service munitions and ammunitions are used. The numerical response is found to corroborate with experimental results. It is observed that, if two consecutive hits are made within a distance of ten times the diameter of the projectile, then it is considered a case of multihit, else, it is considered as single hit case. The damage contours based on effective plastic strain are found to correlate with impact-tested SFRCC panels.
Forming Mechanism of Bump Shape in Pulsed Laser Melting of Stainless Steel
Authors: Shen Hong , Pan Yanqing , Zhou Jing , Yao Zhenqiang
Published: January 2017

Laser surface topography has great applications in mechanical, medical, and electrical industries. This paper proposes a mechanism for the shape formation of stainless steel by pulsed laser melting. A 2D axisymmetric finite element model considering the temperature-dependent surface tension is developed, in which the melt flow and free surface deformation are analyzed by using the normal and shear surface forces. The numerical results show that the molten flows toward the place of the greatest surface tension and the free surface deformation are dominated by the shear force (Marangoni effects), generated by the surface tension gradient during heating phase, and the normal stress, generated by the surface tension at the curved surface during the cooling period.
Heat Transfer Modeling of the Capillary Fiber Drawing Process
Authors: Xue Shicheng , Barton Geoffrey , Fleming Simon , Argyros Alexander
Published: January 2017

Considerable recent research has focused on the ability of microstructured fibers to exhibit diverse optical functionalities. However, accurately preserving the structure imposed at the preform stage after drawing it down to fiber, while avoiding Rayleigh–Plateau style instabilities, has proven to be a major fabrication challenge. This modeling/analytical study was carried out in support of an experimental program into possible fabrication options for various microstructured optical fibers and considers the generic case of the nonisothermal drawing of a capillary preform to fiber. Model development was carried out in two stages. Initially, a fully conjugate multiphase model, which includes all heat transfer modes within an operational fiber drawing furnace, was validated against available experimental data. To evaluate the external radiative heat flux using the net-radiation method, a Monte Carlo ray-tracing (MC-RT) method was coupled to the commercial polyflow package to obtain all view factors between the various furnace walls and the deforming preform/fiber. A simplified model was also developed (to shorten simulation run times) by explicitly calculating the convective heat transfer between the air within the furnace and the preform/fiber surface using a heat transfer coefficient determined by matching predicted results with those obtained from the multiphase model.
A Six Degrees-of-Freedom Vibration Isolation Platform Supported by a Hexapod of Quasi-Zero-Stiffness Struts
Authors: Zhou Jiaxi , Wang Kai , Xu Daolin , Ouyang Huajiang , Li Yingli
Published: January 2017

A platform supported by a hexapod of quasi-zero-stiffness (QZS) struts is proposed to provide a solution for low-frequency vibration isolation in six degrees-of-freedom (6DOFs). The QZS strut is developed by combining a pair of mutually repelling permanent magnets in parallel connection with a coil spring. Dynamic analysis of the 6DOFs QZS platform is carried out to obtain dynamic responses by using the harmonic balance method, and the vibration isolation performance in each DOF is evaluated in terms of force/moment transmissibility, which indicates that the QZS platform perform a good function of low-frequency vibration isolation within broad bandwidth, and has notable advantages over its linear counterpart in all 6DOFs.
Thrombogenicity Testing of Medical Devices in a Minimally Heparinized Ovine Blood Loop
Authors: Grove Kent , Deline Steve M. , Schatz Tim F. , Howard Sarah E. , Porter Deanna , Smith Mark E.
Published: January 2017

ISO 10993-4 in vivo thrombogenicity testing is frequently performed for regulatory approval of many blood-contacting medical devices and is often a key part of submission packages. Given the current state of in vivo thrombogenicity assays, a more robust and reproducible assay design, including in vitro models, is needed. This study describes an in vitro assay that integrates freshly harvested ovine blood containing minimal heparin in a closed pumped loop. To confirm the reproducibility of this assay, control materials were identified that elicited either a positive or a negative thrombogenic response. These controls demonstrated reproducibility in the resulting thrombogenicity scores with median scores of 5 and 0 for the positive and negative controls, respectively, which also demonstrated a significant difference (p < 0.0001). For a direct comparison of the in vitro blood loop assay to the traditional in vivo nonanticoagulated venous implant (NAVI) assay, seven sheep were used as blood donors for the loop and then as subjects for an NAVI assay. In each assay—loop or NAVI—three study articles were used: the positive and negative controls and a marketed, approved catheter. The resulting thrombogenicity scores were similar when comparing the loop to the NAVI results. For each study article, the median thrombogenicity scores were the same in these two different assays, being 0, 1, and 5 for the negative control, the marketed catheter, and the positive control, respectively. These data suggest that the in vitro assay performs similarly to the in vivo NAVI assay. This in vitro blood loop method has the potential to predict a materials' in vivo thrombogenicity, can substantially de-risk the materials or coating selection process, and may eventually be able to replace the in vivo models currently in use.
Benchmarking Severe Accident Computer Codes for Heavy Water Reactor Applications
Authors: Nitheanandan Thambiayah , Cao X. , Choi J.-H. , Dupleac D. , Kim D.-H. , Lele H. G. , Nayak A. K. , Rammohan H. P.
Published: January 2017

The International Atomic Energy Agency (IAEA) organized a coordinated research project (CRP) on “Benchmarking Severe Accident Computer Codes for Heavy Water Reactors (HWR) Applications,” (IAEA TECDOC Series No. 1727), and the activity was completed in 2012. This paper summarizes the results from the CRP: the selection of a severe accident sequence, definition of appropriate geometrical and boundary conditions, benchmarking code analyses, comparison of the code results, evaluation of the capabilities of existing computer codes to predict important severe accident phenomena, and suggestions for code improvements and/or new experiments to reduce uncertainties.
A Similarity Solution for Mixed-Convection Boundary Layer Nanofluid Flow on an Inclined Permeable Surface
Authors: Ziaei-Rad Masoud , Kasaeipoor Abbas , Mehdi Rashidi Mohammad , Lorenzini Giulio
Published: January 2017

This paper concerns with calculation of heat transfer and pressure drop in a mixed-convection nanofluid flow on a permeable inclined flat plate. Solution of governing boundary layer equations is presented for some values of injection/suction parameter (f0), surface angle (γ), Galileo number (Ga), mixed-convection parameter (λ), volume fraction (φ), and type of nanoparticles. The numerical outcomes are presented in terms of average skin friction coefficient (Cf) and Nusselt number (Nu). The results indicate that adding nanoparticles to the base fluid enhances both average friction factor and Nusselt number for a wide range of other effective parameters. We found that for a nanofluid with φ = 0.6, injection from the wall (f0 = −0.2) offers an enhancement of 30% in Cf than the base fluid, while this growth is about 35% for the same case with wall suction (f0 = 0.2). However, increasing the wall suction will linearly raise the heat transfer rate from the surface, similar for all range of nanoparticles volume fraction. The computations also showed that by changing the surface angle from horizontal state to 60 deg, the friction factor becomes 2.4 times by average for all φ's, while 25% increase yields in Nusselt number for the same case. For assisting flow, there is a favorable pressure gradient due to the buoyancy forces, which results in larger Cf and Nu than in opposing flows. We can also see that for all φ values, enhancing Ga/Re2 parameter from 0 to 0.005 makes the friction factor 4.5 times, while causes 50% increase in heat transfer coefficient. Finally, we realized that among the studied nanoparticles, the maximum influence on the friction and heat transfer belongs to copper nanoparticles.
Optimization Method and Simulation Study of a Diesel Engine Using Full Variable Valve Motions
Authors: Lu Yong , Olsen Daniel B.
Published: January 2017

Variable valve timing technologies for internal combustion engines are used to improve power, torque, and increase fuel efficiency. Details of a new solution are presented in this paper for optimizing valve motions of a full variable valve actuation (FVVA) system. The optimization is conducted at different speeds by varying full variable valve motion (variable exhaust open angle, intake close angle, velocity of opening and closing, overlap, dwell duration, and lift) parameters simultaneously; the final optimized valve motions of CY4102 diesel engine are given. The CY4102 diesel engine with standard cam drives is used in large quantities in Asia. An optimized electrohydraulic actuation motion used for the FVVA system is presented. The electrohydraulic actuation and optimized valve motions were applied to the CY4102 diesel engine and modeled using gt-power engine simulation software. Advantages in terms of volumetric efficiency, maximum power, brake efficiency, and fuel consumption are compared with baseline results. Simulation results show that brake power is improved between 12.8% and 19.5% and torque is improved by 10%. Brake thermal efficiency and volumetric efficiency also show improvement. Modeling and simulation results show significant advantages of the full variable valve motion over standard cam drives.
Disturbance Observer-Based Pitch Control of Wind Turbines for Enhanced Speed Regulation
Authors: Yuan Yuan , Chen X. , Tang J.
Published: January 2017

Time-varying unknown wind disturbances influence significantly the dynamics of wind turbines. In this research, we formulate a disturbance observer (DOB) structure that is added to a proportional-integral-derivative (PID) feedback controller, aiming at asymptotically rejecting disturbances to wind turbines at above-rated wind speeds. Specifically, our objective is to maintain a constant output power and achieve better generator speed regulation when a wind turbine is operated under time-varying and turbulent wind conditions. The fundamental idea of DOB control is to conduct internal model-based observation and cancelation of disturbances directly using an inner feedback control loop. While the outer-loop PID controller provides the basic capability of suppressing disturbance effects with guaranteed stability, the inner-loop disturbance observer is designed to yield further disturbance rejection in the low frequency region. The DOB controller can be built as an on–off loop, that is, independent of the original control loop, which makes it easy to be implemented and validated in existing wind turbines. The proposed algorithm is applied to both linearized and nonlinear National Renewable Energy Laboratory (NREL) offshore 5-MW baseline wind turbine models. In order to deal with the mismatch between the linearized model and the nonlinear turbine, an extra compensator is proposed to enhance the robustness of augmented controller. The application of the augmented DOB pitch controller demonstrates enhanced power and speed regulations in the above-rated region for both linearized and nonlinear plant models.