bluuebunny/crossref_metadata_2025 huggingface dataset:
The implementation of a successful medication safety program in a primary care
Authors: Khalil Hanan , Lee Sarah
Published: January 2018

Rationale, aims, and objectives

Improving patient safety is now a government priority in many economically developed and underdeveloped countries. Various medication safety interventions and programs that have been described in the literature focus on hospital settings, and only very few studies report on the implementation of such interventions in primary care.

The main objectives of this study were firstly to describe the steps involved for the successful implementation of a medication safety program in primary care in rural Australia and secondly to report on its evaluation and provide recommendations for future initiatives.

Method

The implementation of the medication safety program within the study organization included several steps, and these were as follows: collection of baseline medications incidents within the organization over the last 2 years, delivery of a medication safety training to clinicians working within the organization, formation of a medication safety group, and implementation of the newly developed medication safety guidelines within the organization. Clinicians' knowledge, behaviour, confidence, and satisfaction were also collected before and after the implementation.

Results

The results show that medication safety training has improved clinicians' knowledge, confidence, behaviour, and utilization positively. There was a significant increase in the clinicians' confidence and satisfaction in applying the training to their daily practice (P value of 0.02).

The implementation of the medication safety program across the study organization sites relied on 3 main stages. These were connect and communicate, collaboration, and consolidation. In the first stage of the project, we focused on identifying the key issues contributing to medication errors across the organization using an evidence‐based approach to identify the types of medications errors.

Conclusion

The success of the implementation of a collaborative medication safety program within a large organization is dependent on emphasizing a wide culture of patient safety and understanding the medication incident reports within an organization.
A study of environmental factors affecting nurses’ comfort and protection in wearing N95 respirators during bedside procedures
Authors: Or Peggy PL , Chung Joanne WY , Wong Thomas KS
Published: January 2018

Aims and objectives

To investigate room temperature and relative humidity affecting nurses’ comfort and protection in wearing N95 respirators during clinical bedside procedures.

Background

N95 respirators are most commonly used to protect healthcare workers against airborne diseases. The elastic head straps required for tight‐fit may cause headache, facial pain and/or ear lobe discomfort. Although some past fit test results showed that these respirators are likely to fit comfortably, in reality, any discomfort from use may influence negatively their appeal and acceptability and thus lower their effectiveness to protect the wearers.

Design

This study used a comparative study design to compare nurses’ comfort and protection in wearing N95 respirator during clinical nursing procedures.

Method

The participants (84) were first‐year undergraduate nursing students from a university in Hong Kong. They were divided randomly into four groups (A, B, C and D), with 21 in each group. In this study, they performed the Personal Respirator Sampling Test (PRST), a self‐developed portable, real‐time fit test method based on the conventional fit test set‐up. After this, they were asked to complete a usability questionnaire, which was used to record their evaluations of the six perceptions of comfort of wearing N95 respirators.

Results

The participants expressed being comfortable with the respirators at warm temperatures of 20 to 24°C. For those participants in Group A who had performed fit tests and fit checks, they did not feel hot nor had difficulties with breathing. However, they did feel tightness in the respirators and experienced discomfort on their ear lobes.

Conclusion

Room temperature is the significant factor affecting the comfort in wearing N95 respirators. It is noteworthy that any discomforts from wearing respirators will negatively influence their appeal and proper use. Without doubt, comfortable fit makes healthcare workers more likely use respirators, hence complying with occupational health and safety regulations.

Relevance to clinical practice

N95 respirator wearer's comfort is affected by room temperature. Wearer's comfort can affect his/her morale in performing bedside procedures in clinical practice.
Experiences of living kidney donors during the donation process
Authors: Agerskov Hanne , Bistrup Claus , Ludvigsen Mette S. , Pedersen Birthe D.
Published: January 2018

Background

The shortage of organs from deceased donors has led to more living donation. Furthermore, immunological developments have made it possible to perform kidney transplantation despite preformed antibodies against the donor organ. This has led to a broader recruitment base of living donors.

Objective

The objective was to investigate experiences and considerations on becoming, and during the process of being, a living kidney donor.

Materials and Methods

: Interviews and participant observation were conducted before, during and after the donation. Data were analysed in accordance with Ricoeur's theory of interpretation on three levels: naïve reading, structural analysis and critical interpretation and discussion. Eighteen potential donors over the age of 18 were included.

Results

Potential donors’ decision to donate was based on a desire to help the recipient. At all stages of the process, donors experienced joy, dilemmas, vulnerability and hope. Rejected donors experienced frustration and disappointment. The accepted donors experienced both joy and vulnerability. Interaction between the donor and the recipient and the relatives played a significant role. The transition from being a healthy individual to being a surgical patient was an overwhelming experience.

Conclusion

The process of donating a kidney and the return to everyday life involved significant experiences of joy, dilemmas, vulnerability and hope that influenced donors’ lives on physical, psychological and social levels. Support and clear communication from the health professionals was essential.
“The Masks We Wear”: A Qualitative Study of Suicide in Australian Farmers
Authors: Kunde Lisa , Kõlves Kairi , Kelly Brian , Reddy Prasuna , de Leo Diego
Published: January 2018

Purpose

Farmer suicide is a major public issue in Australia. Using the psychological autopsy method, this study aimed to examine the life and death circumstances of Australian male farmers who died by suicide through verbal reports from their close significant others.

Methods

Individual semistructured interviews were conducted with 12 relatives of male farmers who had died by suicide in Queensland or New South Wales, Australia (2006‐2014). This study followed the COREQ checklist criteria for the reporting of qualitative research.

Findings

Six interrelated themes were identified: (1) masculinity, (2) uncertainty and lack of control in farming, (3) feelings of failure in relationships and farming, (4) escalating health problems, (5) maladaptive coping, and (6) acquired capability with access to means.

Conclusions

Effective clinical interventions, as well as suicide prevention strategies, need to consider the importance of 3 key issues in suicide among farmers: adherence to masculine norms and socialization; expectations of self in maintaining family traditions and occupation; and a male subtype of depression.
Inter‐rater agreement of novel high‐resolution impedance manometry metrics: Bolus flow time and esophageal impedance integral ratio
Authors: Carlson D. A. , Lin Z. , Kou W. , Pandolfino J. E.
Published: January 2018

Background

Novel high‐resolution impedance manometry (HRIM) metrics of bolus flow time (BFT) and esophageal impedance integral (EII) ratio have demonstrated clinical utility, though the reliability of their analysis has not been assessed. We aimed to evaluate the inter‐rater agreement of the BFT and EII ratio.

Methods

HRIM studies including five upright, liquid swallows from 40 adult patients were analyzed by two raters using a customized MATLAB program to generate the BFT and EII ratio. Inter‐rater agreement was assessed using the intraclass correlation coefficient (ICC) for median values generated per patient and also for all 200 swallows.

Key Results

The ICC (95% confidence interval, CI) for BFT was 0.873 (0.759‐0.933) for median values and 0.838 (0.778‐0.881) for all swallows. The ICC (95% CI) for EII ratio was 0.983 (0.968‐0.991) for median values and 0.905 (0.875‐0.928) for all swallows. Median values for both BFT and EII ratio were similar between the two raters (P‐values .05).

Conclusions and Inferences

The BFT and EII ratio can be reliably calculated as supported by generally excellent inter‐rater agreement. Thus, broader utilization of these measures appears feasible and would facilitate further evaluation of their clinical utility.
Constituent Approval, Electoral Marginality, and Congressional Support for the President
Authors: Cohen Jeffrey E. , Rottinghaus Brandon
Published: January 2018

Controversy exists concerning the effects of approval on congressional support for the president. One source of confusion is the paucity of constituent‐level data for testing the approval–support hypothesis. This study applies multilevel regression poststratification techniques on the Cooperative Congressional Election Study from 2006 through 2012 to estimate constituent approval for both the House and Senate at the member level. Using these data, we test a marginality hypothesis, which suggests that electorally marginal legislators will be more responsive to constituent approval than safe ones. Results indicate support for the approval–support linkage as well as the marginality hypothesis. The marginality effect operates differently across the two chambers and is stronger in the House. The conclusion puts the findings into context and suggests directions for future research.
Success rate of medical thoracoscopy and talc pleurodesis in malignant pleurisy: A single‐centre experience
Authors: Leemans Joke , Dooms Christophe , Ninane Vincent , Yserbyt Jonas
Published: January 2018

Background and objective

Malignant pleurisy is associated with advanced oncological disease and dyspnoea is the most common presenting symptom. Pleurodesis is the preferred palliative and supportive treatment option, targeting symptom relief. The identification of clinical and endoscopic features that determine the success of talc pleurodesis in malignant pleurisy could guide clinical decision‐making.

Methods

All symptomatic patients with malignant pleurisy subjected to talc pleurodesis through medical thoracoscopy between January 2012 and December 2015 were included. Univariate and multivariate analyses were performed to identify factors associated with successful pleurodesis.

Results

Of the 155 patients, 122 (78%) were classified as having a successful pleurodesis based on clinical and radiological criteria. Factors associated with unsuccessful pleurodesis (univariate analysis) were the presence of pleural adhesions (odds ratio (OR): 0.43 (95% CI: 0.19–0.96); P = 0.04), extensive spread of pleural lesions (OR: 0.17 (95% CI: 0.05–0.59); P = 0.001), the use of systemic corticosteroids (OR: 0.28 (95% CI: 0.10–0.83); P = 0.02) and a prolonged time period between the clinical diagnosis of the pleural effusion and the moment of pleurodesis (OR: 0.14 (95% CI: 0.06–0.32); P < 0.0001). The latter being associated with failure of pleurodesis in a multivariate analysis (OR: 0.08 (95% CI: 0.01–0.25); P < 0.0001). Chest ultrasound prior to pleurodesis showed a sensitivity of 91% and a specificity of 88% in predicting the success of pleurodesis.

Conclusion

The success rate of pleurodesis in malignant pleurisy could potentially be enhanced by correct patient selection and early referral for pleurodesis. Ultrasonic assessment of pleural adhesions and potential lung expansion prior to pleurodesis is useful in clinical decision‐making.
Zika virus RNA polymerase chain reaction on the utility channel of a commercial nucleic acid testing system
Authors: Boujnan Mohamed , Duits Ashley J. , Koppelman Marco H.G.M.
Published: January 2018

BACKGROUND

Several countries have implemented safety strategies to reduce the risk of Zika virus (ZIKV) transmission through blood transfusion. These strategies have included nucleic acid amplification testing (NAT) of blood donations. In this study, a new real‐time polymerase chain reaction (PCR) assay including internal control for the detection of ZIKV on the cobas omni Utility Channel (UC) on the cobas 6800 system is presented.

STUDY DESIGN AND METHODS

PCR conditions and primer/probe concentrations were optimized on the LightCycler 480 instrument. Optimized conditions were transferred to the cobas omni UC on the cobas 6800 system. Subsequently, the limit of detection (LOD) in plasma and urine, genotype inclusivity, specificity, cross‐reactivity, and clinical sensitivity were determined.

RESULTS

The 95% LOD of the ZIKV PCR assay on the cobas 6800 system was 23.0 IU/mL (95% confidence interval [CI], 16.5‐37.5) in plasma and 24.5 IU/mL (95% CI, 13.4‐92.9) in urine. The assay detected African and Asian lineages of ZIKV. The specificity was 100%. The clinical concordance between the newly developed ZIKV PCR assay and the investigational Roche cobas Zika NAT test was 83% (24/29).

CONCLUSIONS

We developed a sensitive ZIKV PCR assay on the cobas omni UC on the cobas 6800 system. The assay can be used for large‐scale screening of blood donations for ZIKV or for testing of blood donors returning from areas with ZIKV to avoid temporal deferral. This study also demonstrates that the cobas omni UC on the cobas 6800 system can be used for in‐house–developed PCR assays.
Clinical characteristics and outcome in dogs with small cell T‐cell intestinal lymphoma
Authors: Couto K. M. , Moore P. F. , Zwingenberger A. L. , Willcox J. L. , Skorupski K. A.
Published: January 2018

Small cell intestinal lymphoma has not been well characterized in dogs. The objective of this study was to describe clinical characteristics and outcome in dogs with small cell intestinal lymphoma. We hypothesized that affected dogs would have prolonged survival compared with high‐grade gastrointestinal (GI) lymphoma. Pathology records were searched for dogs with histologically confirmed small cell GI lymphoma. Seventeen dogs with confirmed small cell intestinal lymphoma were identified, and clinical and outcome data were retrospectively collected. Histopathology was reviewed by a board‐certified pathologist, and tissue sections were subjected to immunophenotyping and molecular clonality assessment. All dogs had small cell, T‐cell, lymphoma confirmed within various regions of small intestine, with 1 dog also having disease in abdominal lymph nodes. All dogs had clinical signs attributable to GI disease; diarrhoea (n = 13) was most common. Ultrasonographic abnormalities were present in 8 of 13 dogs with abnormal wall layering (n = 7) and hyperechoic mucosal striations (n = 7) representing the most common findings. In total, 14 dogs received some form of treatment. The median survival time (MST) for all dogs was 279 days and the MST for the 14 dogs that received any treatment was 628 days. Dogs with anaemia and weight loss at presentation had significantly shorter survival times and dogs that received a combination of steroids and an alkylating agent had significantly longer survival times. Small cell, T‐cell, intestinal lymphoma is a distinct disease process in dogs, and those undergoing treatment may experience prolonged survival.
Effect of an oxygen‐generating scaffold on the viability and insulin secretion function of porcine neonatal pancreatic cell clusters
Authors: Lee Eun Mi , Jung Ji‐In , Alam Zahid , Yi Hee‐Gyeong , Kim Heejin , Choi Jin Woo , Hurh Sunghoon , Kim Young June , Jeong Jong Cheol , Yang Jaeseok , Oh Kook‐Hwan , Kim Hee Chan , Lee Byeong Chun , Choi Inho , Cho Dong‐Woo , Ahn Curie
Published: January 2018

Background

Islet encapsulation techniques have shown limited success in maintaining islet survival and function because encapsulation decreases oxygen supply. In this study, an oxygen‐generating scaffold was fabricated to prevent hypoxic cell damage and improve the viability and insulin secretion of islets.

Methods

We fabricated an oxygen‐generating scaffold by mixing calcium peroxide (CaO2) with polydimethylsiloxane (PDMS). We evaluated the effects of the oxygen‐generating PDMS + CaO2 scaffold on viability, caspase‐3 and caspase‐7 activity, oxygen consumption rate (OCR), glucose‐stimulated insulin secretion (GSIS), hypoxic cell marker expression, and reactive oxygen species (ROS) levels in porcine neonatal pancreatic cell clusters (NPCCs). We also fabricated a microfluidic device that allowed measuring the effects of the oxygen‐generating scaffold on viability.

Results

Oxygen generation by the PDMS + CaO2 scaffold was sustained for more than 24 hours in vitro. NPCCs encapsulated in PDMS + CaO2 showed higher viability than NPCCs in PDMS scaffolds and control NPCCs grown without a scaffold. PDMS + CaO2‐encapsulated NPCCs showed lower caspase‐3 and caspase‐7 activity, hypoxic cell expression, and ROS levels, and higher OCR and GSIS than those in PDMS or control cells. Using the microfluidic device, we observed that the viability of PDMS + CaO2‐encapsulated NPCCs was higher than that of PDMS‐encapsulated NPCCs.

Conclusions

NPCCs in PDMS + CaO2 scaffolds show higher viability and insulin secretion than do NPCCs in PDMS scaffolds and control cells. Therefore, this oxygen‐generating scaffold has potential for application in future islet transplantation studies.
Observer variation in the delineation of organs at risk for head and neck radiation therapy treatment planning: a systematic review protocol
Authors: Moore Alisha
Published: January 2018

Review question:

The objective of this review is to examine inter- and intra-observer agreement and reliability in the delineation of head and neck organs at risk (OAR) as part of the radiation therapy treatment planning process.

More specifically, the objectives are to identify:

i. The level of agreement and reliability among multiple observers in defining normal tissue in the head and neck region in both computed tomography (CT) and magnetic resonance imaging (MRI) scans.

ii. The level of agreement and reliability for single observers at different time points in defining normal tissue in the head and neck region on both CT and MRI scans.

iii. The contouring methods used to delineate head and neck organs at risk (OAR) in studies of intra and inter-observer reliability and agreement. Such contouring methods may include the use of software packages, education, technology and multi-modality imaging such as CT and MRI.
The association between paternal body mass index, pregnancy success and child health outcomes: a systematic review protocol
Authors: Campbell Jared M. , McPherson Nicole O.
Published: January 2018

Review question:

The objective of this review is to investigate the association between paternal body mass index (BMI) (particularly elevated paternal BMI) and complications of conception and pregnancy as well as neonatal and childhood health.
The impact of outpatient telehealth compared to standard care on emergency room visits and hospital admissions in pediatric diabetes patients: a systematic review protocol
Authors: Armstrong Katelyn , Moore Mary M.
Published: January 2018

Review question:

What is the effectiveness of outpatient telehealth compared to standard care on emergency room and hospital admissions in patients aged 0 to 18 years with type 1 or type 2 diabetes?
Additive Manufacturing-Enabled Part Count Reduction: A Lifecycle Perspective
Authors: Yang Sheng , Zhao Yaoyao Fiona
Published: January 2018

Part count reduction (PCR) is one of the typical motivations for using additive manufacturing (AM) processes. However, the implications and trade-offs of employing AM for PCR are not well understood. The deficits are mainly reflected in two aspects: (1) lifecycle-effect analysis of PCR is rare and scattered; (2) current PCR rules lack full consideration of AM capabilities and constraints. To fill these gaps, this paper first summarizes the main effect of general PCR (G-PCR) on lifecycle activities to make designers aware of potential benefits and risks and discusses in a point-to-point fashion the new opportunities and challenges presented by AM-enabled PCR (AM-PCR). Second, a new set of design rules and principles are proposed to support potential candidate detection for AM-PCR. Third, a dual-level screening and refinement design framework is presented aiming at finding the optimal combination of AM-PCR candidates. In this framework, the first level down-samples combinatory space based on the proposed new rules while the second one exhausts and refines each feasible solution via design optimization. A case study of a motorcycle steering assembly is considered to demonstrate the effectiveness of the proposed design rules and framework. In the end, possible challenges and limitations of the presented design framework are discussed.
Towards a Numerical Approach of Finding Candidates for Additive Manufacturing-Enabled Part Consolidation
Authors: Yang Sheng , Santoro Florian , Zhao Yaoyao Fiona
Published: January 2018

Part consolidation (PC) is one of the typical design freedoms enabled by additive manufacturing (AM) processes. However, how to select potential candidates for PC is rarely discussed. This deficiency has hindered AM from wider applications in industry. Currently available design guidelines are based on obsolete heuristic rules provided for conventional manufacturing processes. This paper first revises these rules to take account of AM constraints and lifecycle factors so that efforts can be saved and used at the downstream detailed design stage. To automate the implementation of these revised rules, a numerical approach named PC candidate detection (PCCD) framework is proposed. This framework is comprised of two steps: construct functional and physical interaction (FPI) network and PCCD algorithm. FPI network is to abstractly represent the interaction relations between components as a graph whose nodes and edges have defined physical attributes. These attributes are taken as inputs for the PCCD algorithm to verify conformance to the revised rules. In this PCCD algorithm, verification sequence of rules, conflict handling, and the optimum grouping approach with the minimum part count are studied. Compared to manual ad hoc design practices, the proposed PCCD method shows promise in repeatability, retrievability, and efficiency. Two case studies of a throttle pedal and a tripod are presented to show the application and effectiveness of the proposed methods.
Severe Accident Context Quantification for Long-Term Station Blackout in Boiling Water Reactor Nuclear Power Plants
Authors: Petkov Gueorgui I. , Vela-Garcia Monica
Published: January 2018

The realistic study of dynamic accident context is an invaluable tool to address the uncertainties and their impact on safety assessment and management. The capacities of the performance evaluation of teamwork (PET) procedure for dynamic context quantification and determination of alternatives, coordination, and monitoring of human performance and decision-making are discussed in this paper. The procedure is based on a thorough description of symptoms during the accident scenario progressions with the use of thermo-hydraulic (TH) model and severe accident (SA) codes (melcor and maap). The opportunities of PET procedure for context quantification are exemplified for the long-term station blackout (LT SBO) accident scenario at Fukushima Daiichi #1 and a hypothetic unmitigated LT SBO at peach bottom #1 boiling water reactor (BWR) reactor nuclear power plants (NPPs). The context quantification of these LT SBO scenarios is based on the IAEA Fukushima Daiichi accident report, “State-of-the-Art Reactor Consequence Analysis” and TH calculations made by using maap code at the EC Joint Research Centre.
Finite Element and Smoothed Particle Hydrodynamics Modeling of Fluid–Structure Interaction Using a Unified Computational Methodology
Authors: Challa Ravi , Yim Solomon C.
Published: January 2018

This study illustrates a comparison of two numerical methods under a unified computational platform for solving fluid–structure interaction (FSI) problems. The first is an arbitrary Lagrangian–Eulerian (ALE)-based fluid model coupled to a structural finite element (FE) method (ALE-FE/FE), and the second is a smoothed particle hydrodynamics (SPH) method coupled to the same structural FE code (SPH/FE). The predictive capabilities and computational efficiency of both the numerical methods are evaluated and validated against a canonical problem of a rapidly varying flow past an elastic gate for which experimental data are available. In both numerical solutions, the fluid flow is governed by the Navier–Stokes equation, and the elastic gate is modeled as a flexible structure. Numerical simulation results show that the ALE-FE/FE continuum approach not only captures the dynamic behavior properly but also predicts the water-free surface profiles and the elastic gate deformations accurately. On the other hand, the coupled purely Lagrangian approach of the SPH/FE under an identical computational platform is found to be less accurate and efficient in predicting the dynamics of the elastic gate motion and the water-free surface profiles.
Utilization of a Two-Beam Cantilever Array for Enhanced Atomic Force Microscopy Sensitivity
Authors: Jackson Samuel , Gutschmidt Stefanie
Published: January 2018

An array of cantilevers offers an alternative approach to standard single beam measurement in the context of atomic force microscopy (AFM). In comparison to a single beam, a multi-degrees-of-freedom system offers a greater level of flexibility with regard to parameter selection and tuning. By utilizing changes in the system eigenmodes as a feedback signal, it is possible to enhance the sensitivity of AFM to changes in sample topography above what is achievable with standard single beam techniques. In this paper, we analyze a two-beam array operated in FM-AFM mode. The array consists of a single active cantilever that is excited with a 90 deg phase-shifted signal and interacts with the sample surface. The active beam is mechanically coupled to a passive beam, which acts to vary the response between synchronized and unsynchronized behavior. We use a recently developed mathematical model of the coupled cantilever array subjected to nonlinear tip forces to simulate the response of the described system with different levels of coupling. We show that the sensitivity of the frequency feedback signal can be increased significantly in comparison to the frequency feedback from a single beam. This is a novel application for an AFM array that is not present in the literature.
Ultraviolet-Activated Frequency Control of Beams and Plates Based on Isogeometric Analysis
Authors: Guo Yujie , Tzou Hornsen
Published: January 2018

A new light-activated shape memory polymer (LaSMP) smart material exhibits shape memory behaviors and stiffness variation via ultraviolet (UV) light exposures. This dynamic stiffness provides a new noncontact actuation mechanism for engineering structures. Isogeometric analysis (IGA) utilizes high order and high continuity nonuniform rational B-spline (NURBS) as basis functions which naturally fulfills C1-continuity requirement of Euler–Bernoulli beam and Kirchhoff plate theories. Compared with the traditional finite elements of beams and plates, IGA does not need extra rotational degrees-of-freedom while providing accurate results. The UV light-activated frequency control of LaSMP fully and partially laminated beam and plate structures based on the IGA is presented in this study. For the analysis of LaSMP partially laminated plates, the finite cell approach in the framework of IGA is proposed to handle NURBS geometries containing trimming features. The accuracy and efficiency of the proposed isogeometric approach are demonstrated via several numerical examples in frequency control. The results show that, with LaSMPs, broadband frequency control of beam and plate structures can be realized. Furthermore, changing LaSMP patch sizes on beams and plates further broadens its frequency control ranges. Studies suggest that: (1) the newly developed IGA combining finite cell approach is an effective numerical tool and (2) the maximum frequency manipulation ratios of beam and plate structures, respectively, reach 24.30% and 16.75%, which demonstrates the feasibility of LaSMPs-induced vibration control of structures.
Transfer Function Analysis of Constrained, Distributed Piezoelectric Vibration Energy Harvesting Beam Systems
Authors: An Tan Chin , Amoozegar Shahram , Lai Heather L.
Published: January 2018

This paper presents a novel formulation and exact solution of the frequency response function (FRF) of vibration energy harvesting beam systems by the distributed transfer function method (TFM). The method is applicable for coupled electromechanical systems with nonproportional damping, intermediate constraints, and nonclassical boundary conditions, for which the system transfer functions are either very difficult or cumbersome to obtain using available methods. Such systems may offer new opportunities for optimized designs of energy harvesters via parameter tuning. The proposed formulation is also systematic and amenable to algorithmic numerical coding, allowing the system response and its derivatives to be computed by only simple modifications of the parameters in the system operators for different boundary conditions and the incorporation of feedback control principles. Examples of piezoelectric energy harvesters with nonclassical boundary conditions and intermediate constraints are presented to demonstrate the efficacy of the proposed method and its use as a design tool for vibration energy harvesters via tuning of system parameters. The results can also be used to provide benchmarks for assessing the accuracies of approximate techniques.
A Fast Approximate Method for Heat Conduction in an Inhomogeneous Half-Space Subjected to Frictional Heating
Authors: Shi Xiujiang , Wang Liqin , Zhou Qinghua , Wang Qian
Published: January 2018

This paper reports a new three-dimensional model for heat conduction in a half-space containing inhomogeneities, applicable to frictional heat transfer, together with a novel combined algorithm of the equivalent inclusion method (EIM) and the imaging inclusion approach for building this model. The influence coefficients (ICs) for temperature and heat flux are obtained via converting the frequency response function (FRF) and integrating Green's function. The model solution is based on the discrete convolution and fast Fourier transform (DC-FFT) algorithm using the ICs, convenient for solving problems involving multiple elliptical inhomogeneities with arbitrary orientations. A group of parametric studies are conducted for understanding the thermal fields in the inhomogeneous half-space due to surface frictional heating, influenced by the properties of the inhomogeneity, its depth, and orientation.
Handling Perception Uncertainty in Simulation-Based Singulation Planning for Robotic Bin Picking
Authors: Kumbla Nithyananda B. , Thakar Shantanu , Kaipa Krishnanand N. , Marvel Jeremy , Gupta Satyandra K.
Published: January 2018

Robotic bin picking requires using a perception system to estimate the posture of parts in the bin. The selected singulation plan should be robust with respect to perception uncertainties. If the estimated posture is significantly different from the actual posture, then the singulation plan may fail during execution. In such cases, the singulation process will need to be repeated. We are interested in selecting singulation plans that minimize the expected task completion time. In order to estimate the expected task completion time for a proposed singulation plan, we need to estimate the probability of success and the plan execution time. Robotic bin picking needs to be done in real-time. Therefore, candidate singulation plans need to be generated and evaluated in real-time. This paper presents an approach for utilizing computationally efficient simulations for generating singulation plans. Results from physical experiments match well with the predictions obtained from simulations.
Building Vibration Control by Active Mass Damper With Delayed Acceleration Feedback: Multi-Objective Optimal Design and Experimental Validation
Authors: Zheng Yuan-Guang , Huang Jing-Wen , Sun Ya-Hui , Sun Jian-Qiao
Published: January 2018

The building structural vibration control by an active mass damper (AMD) with delayed acceleration feedback is studied. The control is designed with a multi-objective optimal approach. The stable region in a parameter space of the control gain and time delay is obtained by using the method of stability switch and the numerical code of NDDEBIFTOOL. The control objectives include the setting time, total power consumption, peak time, and the maximum power. The multi-objective optimization problem (MOP) for the control design is solved with the simple cell mapping (SCM) method. The Pareto set and Pareto front are found to consist of two clusters. The first cluster has negative feedback gains, i.e., the positive acceleration feedback. We have shown that a proper time delay can enhance the vibration suppression with controls from the first cluster. The second cluster has positive feedback gains and is located in the region which is sensitive to time delay. A small time delay will deteriorate the control performance in this cluster. Numerical simulations and experiments are carried out to demonstrate the analytical findings.
Divers Augmented Vision Display (DAVD)
Authors: Manley Richard J. , Gallagher Dennis G. , Hughes William W. , Pilcher Allie M.
Published: January 2018

Military diving operations are routinely conducted in what can be one of the most inhospitable environments on the planet, frequently characterized by zero visibility. The inability to clearly see the immediate operational environment has historically been a serious limitation to manned diving operations — whether the mission is ship husbandry, under water construction, salvage, or scientific research.

U.S. Navy diving is an integral part of the nation’s defense strategy with a continuing requirement to conduct manned intervention in the water column. To ensure technical superiority across the entire spectrum of diving operations we must identify, exploit, and de velop technology to advance the state-of-the-art in diving equipment. This can only be achieved by investing in, and supporting, focused research and development with specific goals to further diving capabilities.

Under a project sponsored by the Office of Naval Research (ONR) and Naval Sea Systems Command (NAVSEA), the Naval Surface Warfare Center-Panama City Division (NSWC PCD) has de veloped a prototype see-through head-up display system for a U. S. Navy diving helmet — the Divers Augmented Vision Display (DAVD). The DAVD system uses waveguide optical display modules that couple images from a micro display into a waveguide optic, translate the images through a series of internal reflections, finally exiting toward the diver’s eye providing a magnified, see-through virtual image at a specific distance in front of the diver. The virtual images can be critical information and sensor data including sonar images, ship husbandry and underwater construction schematics, enhanced navigation displays, augmented reality, and text messages.

NSWC PCD is the U.S. Navy’s leading laboratory for research, development, testing, evaluation, and technology transition of diver visual display systems; with unique facilities for rapid prototyping and manufacturing, human systems integration and extreme environment testing. Along with NSWC PCD, the Navy Experimental Diving Unit (NEDU), and Naval Diving and Salvage Training Center (NDSTC) are co-located tenant commands at the Naval Support Activity Panama City (NSA PC).

This paper provides a brief background on the development of diver head-up display systems, waveguide optical display technology, development of the DAVD prototype, results of diver evaluations, and recommendations for accelerated development of this game changing capability.
Modelling, Analyses and Optimization for Exergy Performance of an Irreversible Intercooled Regenerated Brayton CHP Plant: Part 2 — Performance Optimization
Authors: Yang Bo , Chen Lingen , Feng Huijun , Ding Zemin
Published: January 2018

In the Part 1 of this paper, a variable temperature heat reservoir irreversible intercooling regenerative Brayton combined heat and power (CHP) plant model is set up, and the exergy efficiency and exergy output rate formulae are obtained. The optimization of pressure ratios and the influence analyses of some vital parameters on the exergy performances are carried out. In this Part, the heat conductance distributions about the high temperature-side heat exchanger, regenerator, intercooler, thermal consumer exchanger and low temperature-side heat exchanger, and the pressure ratios are optimized step by step. The effects of main parameters (such as of turbine and compressor efficiencies, working substance pressure drop loss, heat consumer required temperature, and so on) on the optimum exergy performances are investigated, and the heat capacitance rate matching between the heat reservoirs and working substance is studied.
Anisotropic Behavior of Aluminum Alloy 2024-Graphene Composites at Varying Strain Rates
Authors: Anthony Xavior M. , Hosamane Prashantha Kumar , Paulchamy Jeyapandiarajan
Published: January 2018

In fabrication of high strength materials coupled with improved mechanical properties; focus on integration of multifunctional reinforcements are increasing along with novel processing methods. Single layer 2-D material Graphene are among one such novel material with huge aspect ratio, posse’s high strength. But the real challenge is processing and incorporation of these reinforcements with appropriate content in metals or its alloys matrix. Current research work focus to study the anisotropic behavior on addition of pristine Graphene/MWCNT and processing methods like ball milling under constant ball to powder precursor ratio (BPR) of AA 2024 nanocomposites. The extent change in aspect ratio, size of the nanoparticle mixtures during ball milling were analyzed under SEM and Raman spectroscopy. Thus obtained (ball milled) precursors are consolidated through vacuum hot press and hot extruded to get typical flat specimen at optimized processing parameters. XRD analysis, relative density and hardness measurement is done on extruded composites. Thus developed composites are subjected to study the anisotropic behavior at various orientations and strain rates (0.5, 1.0, 1.5 mm/min) using uniaxial tensile testing instrument and corresponding stress strains graphs were obtained. The fracture surfaces were characterized by scanning electron microscope (SEM) and its shows the nucleation of the dimple size are varies with increasing the strain rate and also deeper dimple size were noticed. Negative strain sensitivity were observed for the lower strain rate (0.1 and 0.3 mm/min) and positive strain sensitivity for higher strain rates. Microstructural anisotropy infers that AA2024-Graphene/MWCNT composites are sensitive to strain rate and shear type of failure is observed on increasing the strain rate.
Geometrical Variation Simulation for Assembly With Form Defects
Authors: Goka Edoh , Homri Lazhar , Beaurepaire Pierre , Dantan Jean-Yves
Published: January 2018

To improve product quality, tolerance analysis represents nowadays a key element in industry. It aims to verify whether allocated tolerances satisfy functional and assembly requirements. Tolerance analysis approaches are generally proposed considering idealized surfaces (such as planes, cylinders, spheres, etc.) and the shape of the components is parameterized to take into account the geometric deviations. However, this approach considers only ideal substitute models, which may strongly differ from the actual geometry of the manufactured components. To enable high-precision products, there is a strong need to integrate parts form defects in the assembly modeling. Form defects are firstly generated by modal decomposition: a basis of modes of deviation is predefined and each mode is associated with a randomly generated weight to account the variability in the geometry of the components. The form defects are subsequently taken into account when handling with constraints in assembly with gaps. Assembly simulation is defined by a mathematical optimization problem, which includes the definition of the signed distance between points of the surfaces undergoing form defects and potentially in contact. The contact configuration is assessed by determining the relative positioning of parts in the assembly. An application example demonstrates the relevance of the procedure; it considers two surfaces classes: planes and cylinders. The assembly probability and functional probability are computed when mechanism is rigid and which is firstly without form defects and then with form defects. The paper closes with a comparison between the reference methods and the proposed procedure.
A Comparative Analysis and Evaluation of Model Selection Criteria
Authors: Kamel Ahmed H. , Shaqlaih Ali S. , Rozyyev Arslan
Published: January 2018

The ongoing research for model choice and selection has generated a plethora of approaches. With such a wealth of methods, it can be difficult for a researcher to know what model selection approach is the proper way to proceed to select the appropriate model for prediction.

The authors present an evaluation of various model selection criteria from decision-theoretic perspective using experimental data to define and recommend a criterion to select the best model. In this analysis, six of the most common selection criteria, nineteen friction factor correlations, and eight sets of experimental data are employed. The results show that while the use of the traditional correlation coefficient, R2 is inappropriate, root mean square error, RMSE can be used to rank models, but does not give much insight on their accuracy. Other criteria such as correlation ratio, mean absolute error, and standard deviation are also evaluated. The Akaike information criterion, AIC has shown its superiority to other selection criteria. The authors propose AIC as an alternative to use when fitting experimental data or evaluating existing correlations. Indeed, the AIC method is an information theory based, theoretically sound and stable. The paper presents a detailed discussion of the model selection criteria, their pros and cons, and how they can be utilized to allow proper comparison of different models for the best model to be inferred based on sound mathematical theory. In conclusion, model selection is an interesting problem and an innovative strategy to help alleviate similar challenges faced by the professionals in the oil and gas industry is introduced.
Study of Gas Flow Through a Stirling Engine Regenerator
Authors: Rogdakis E. , Bitsikas P. , Dogkas G.
Published: January 2018

In the present work, a three dimensional (3D) Computational Fluid Dynamics (CFD) analysis is applied to a designed small compact regenerator with specific porosity and wire diameter. The regenerator was studied as a part of a Stirling Engine designed in a simple way.

The gas temperature along the regenerator followed an approximately linear profile, while the metal temperature showed a small deviation during the engine cycle. The heat transfer coefficient between the gas and the matrix of the regenerator, along with the associate heat transferred were also derived. The heat exchanged in the regenerator is significantly higher to the respective heat in the engine’s heater and cooler.

Additionally, the pressure drop and the related energy dissipation are studied. Their variation is largely dependent on both mass flow-rate and working gas velocity. The friction factor coefficient for the designed regenerator is correlated with Reynolds number and an equation of two variables is derived.

Finally, the results of the CFD simulation are compared to those produced by a one-dimensional numerical model. These results include gas mass, mass flow-rate and Reynolds number, as well as the heat transferred between the gas and the regenerator matrix. Except for the case of the exchanged heat, the deviation between the two approaches is very small.
Investigation of Damping Nonlinearity in Duffing-Type Vibration Isolation System With Geometric and Magnetic Stiffness Nonlinearities
Authors: Mofidian S. M. Mahdi , Bardaweel Hamzeh
Published: January 2018

In this work, the effect of nonlinear damping in presence of geometric nonlinearities and magnetic stiffness nonlinearities in vibration isolation system is investigated. The dynamic behavior of the isolation system design is modeled. Harmonic Balance Method (HBM) is used to investigate the dynamic behavior of the vibration isolation system in response to sinusoidal input waveform. Results obtained using the HBM are compared to the results from numerical simulation attained using Runge-kutta method. Results show that introducing nonlinear viscous damping into the vibration isolation system suppresses frequency jump phenomena observed in Duffing-type vibration isolation systems. Additionally, results show that nonlinear damping can suppress transmissibility around resonant peak. For frequencies lower than resonant frequency the effect of nonlinear damping is minimum compared to a linear isolation system. Beyond resonant frequency higher nonlinear damping may slightly alter transmissibility of the isolation system.
Rarefied Gas Flow Analysis of a Suborbital Shuttle With the Academic CFD Code Galatea
Authors: Klothakis Angelos G. , Lygidakis Georgios N. , Nikolos Ioannis K.
Published: January 2018

During the past decade considerable efforts have been exerted for the simulation of rarefied gas flows in a wide range of applications, like the flow over suborbital vehicles, in microelectromechanical systems, etc. Such flows appear to be significantly different from those at the continuum regime, making the Navier-Stokes equations to fail without further amendment. In this study an in-house academic CFD solver, named Galatea, is modified appropriately to account for rarefied gases. The no-slip condition on solid walls is no longer valid, hence, velocity slip and temperature jump boundary conditions are applied instead. Additionally, a second-order accurate slip model has been incorporated, namely, this of Beskok and Karniadakis, increasing the accuracy in the same area but avoiding simultaneously the numerical difficulties, entailed by the computation of the second derivative of slip velocity when complex geometries and unstructured grids are coupled. The proposed solver is validated against rarefied laminar flow over a suborbital shuttle, designed by the Azim’UTBM team. The obtained results are compared with those extracted with the parallel open-source kernel SPARTA, which is based on the DSMC method. A satisfactory agreement is reported between the two methodologies, demonstrating the potential of the modified solver to simulate effectively such flows.