bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Optimization of Functionally Graded Superelastic NiTi Stents
Authors: Khurana Jivtesh B. , Frecker Mary , Pauli Eric M. 
Published: November 2020

Abstract
Endoscopic stents are being used by surgeons in off-label uses to manage leaks and perforations in the gastrointestinal tract. Commercially available stents are primarily designed to open strictures in the esophagus through tissue compression. The stents incorporate a woven NiTi wire to produce a stiff and linear tubular shape that conforms to the esophagus. In off-label uses, where the stents are placed in non-esophageal locations the stents must bend, the stents show a high propensity to migrate from their initial location causing unwanted complications. In this paper, a new stent design incorporating functionally graded NiTi is presented and explored. First, a functionally graded NiTi stent design is proposed. Next, a mechanical model using finite element analysis is developed to predict the bending moment and stiffness of the functionally graded stent designs. Finally, the mechanical model is coupled with a genetic algorithm in MATLAB to identify optimal designs. For a 90° bending angle, the best design parameters of the newly proposed flexible stents are found for three different stent design families. The results of the functionally graded stents show how tailoring the material properties locally in a structure can lead to highly compliant behavior. The tailoring of the geometric and material design developed may be applied to design of highly flexible and optimized medical devices.
Generative Infills for Additive Manufacturing Using Space-Filling Polygonal Tiles
Authors: Ebert Matthew , Subramanian Sai Ganesh , Akleman Ergun , Krishnamurthy Vinayak R. 
Published: November 2020

Abstract
We study a new class of infill patterns, that we call wallpaper-infills for additive manufacturing based on space-filling shapes. To this end, we present a simple yet powerful geometric modeling framework that combines the idea of Voronoi decomposition space with wallpaper symmetries defined in 2-space. We first provide a geometric algorithm to generate wallpaper-infills and design four special cases based on selective spatial arrangement of seed points on the plane. Second, we provide a relationship between the infill percentage to the spatial resolution of the seed points for our cases thus allowing for a systematic way to generate infills at the desired volumetric infill percentages. Finally, we conduct a detailed experimental evaluation of the of these four cases to study their mechanical behavior under tensile loading.
Stability Region-Based Analysis of Walking and Push Recovery Control
Authors: Peng William Z. , Song Hyunjong , Kim Joo H. 
Published: November 2020

Abstract
Push recovery is a vital aspect of balance stability control in biped robots. In this work, the response of a biped system to unexpected external perturbations is analyzed for different tasks and controllers using stability criteria based on balanced and steppable regions. The steppable region for a given step length and the balanced regions for single and double support contacts are constructed for a biped robot using optimization with its system dynamics, kinematic limits, actuation limits, and contact interactions with the environment. The regions are compared with those of a human subject to demonstrate that human gait exhibits unbalanced (but steppable) phases largely absent in robotic gait. These regions are also applied to a comparative analysis against capturability, where the computed steppable region is significantly larger than the capture region of an equivalent reduced-order model. The stability regions are also used to compare the performance of controllers during a double support balancing task. The implemented hip, knee, and ankle strategy-based controller led to improved stabilization — i.e., decreased foot tipping and time required to balance — relative to an existing hip and ankle controller and a gyro feedback controller. The proposed approaches are applicable to the analysis of any bipedal task and stability controller in general.
Design of an Onboard Directional Anemometer for Bicycles
Authors: Hurtado Valentina , Arango Santiago , Muñoz Luis , López Omar 
Published: November 2020

Abstract
Wind speed has large influence on the results of road tests applied to bicycles. For this reason, this paper presents the design process of an onboard anemometer dedicated to bicycle testing. The design provides an affordable way to quantify both magnitude and direction of the wind velocity relative to the bicycle, allowing recording on arbitrary wind conditions that could arise during a test.
The design methodology was structured with two major phases. The first was centered on the proof-of-concept for the use of a multi-hole pitot tube as main component for the onboard anemometer. The second was focused on the design of the structure, considering both packaging and structural integrity.
The prototype of anemometer was tested in a wind tunnel to verify its performance, and it was also tested under severe vibrations to verify its structural integrity. The results showed that this concept can be used as a part of the bicycle instrumentation for road tests.
Paired Computer-Aided Design: The Effect of Collaboration Mode on Differences in Model Quality
Authors: Arshad Hamza , Phadnis Vrushank , Olechowski Alison 
Published: November 2020

Abstract
We present the results of an experiment investigating two different modes of collaboration on a series of computer-aided design (CAD) tasks. Inspired by the pair programming literature, we anticipate that partners working in a fully synchronous collaborative CAD environment will achieve different levels of quality in CAD models depending on their mode of collaboration — one in which the pair is free to work in parallel, and another where the pair must coordinate to share one control.
We found that a shared CAD control led to significantly better overall CAD quality than parallel CAD control. In addition, the shared control mode led to more complete and consistent CAD models, as well as the tendency for participants to follow instructions to correctly replicate features for the design task. As is predicted in the literature, a trade-off relationship (albeit weak) between quality and speed via the parallel collaboration was found. In contrast, the shared control mode shows no clear relationship between speed and quality.
Collaborative CAD is increasingly seen as an appealing tool for modern product design teams. This study suggests that the benefits of this tool are not solely the effect of the tool itself, but result from the collaboration style of the designers using the tool.
Extracting Maximum Power in the Presence of Internal Inductance of Electromagnetic Energy Harvesting Systems
Authors: Sharma Yamini , Zuo Lei 
Published: November 2020

Abstract
In this paper, the effect of internal inductance of electromagnetic generators in the field of energy harvesting is discussed. Electromagnetic energy harvesters are typically operated at low frequencies. This results in the generator internal inductor impedance being significantly less than the generator internal resistance. However, at high frequencies, this inductance can no longer be ignored. Therefore, to maximize the harvested power, the internal inductance must be considered while designing the power electronics. This paper presents two methods to tackle this issue. The first method involves making use of a discrete capacitor which is able to reduce the inductance effect not just at resonant frequency but for the entire operating frequency range. The second method makes use of a concept similar to synchronized switching harvesting on inductors (SSHI) in piezoelectric energy harvesting. A capacitor and switch are added in the electromagnetic energy harvesting circuit to reduce the generator internal inductance effect. This method not only provides the benefit of performing well in the entire operating frequency range but also eliminates the need for precise maximum power tracking techniques, which further helps in reducing the circuit losses. Simulation results show a maximum power output increase of 56%.
Influence of the Chainring Geometry on the Critical Power of Recreational Cyclists
Authors: Acevedo Orlando , Muñoz Luis , Polanco Alejandra , Suárez Daniel 
Published: November 2020

Abstract
Science has come to a disagreement regarding the real effect that chainrings’ geometry has on cyclists’ performance. In this study, the influence of the use of a noncircular chainring on recreational cyclists’ performance is determined through experimental power delivery tests. A critical power model was used to estimate variations on cyclists’ performance. In addition, a new protocol for estimating critical power was proposed.
Fourteen recreational cyclists (two females and twelve males) performed a series of self-paced constant-time tests with a circular and a noncircular (i.e., Osymetric) chainring during two different test sessions. Power output, cadence and time were registered to compute the critical power.
According to the results of this study, it seems there is a change in the critical power of the majority of the recreational cyclists due to the use of a noncircular chainring. Thus, a performance improvement was obtained during long-endurance tests. However, the order of the tests (i.e., starting with the circular chainring or starting with the noncircular chainring) was proven to have an impact on the results due to a familiarization effect to the test conditions. Finally, a new protocol to estimate the critical power of a cyclist by performing a single riding session was proposed and assessed on a pilot test (i.e., error &lt; 3%).
Finite Element Model for Prediction of Ground Vehicle Mobility Over Vegetation Covered Terrains
Authors: Wasfy Tamer , Wasfy Hatem , Jayakumar Paramsothy , Sanikommu Srinivas 
Published: November 2020

Abstract
A finite element vegetation model is presented for predicting the dynamic interaction of ground vehicles with vegetation. The purpose of the model is to predict ground vehicle mobility over vegetation covered terrains. The types of vegetation can range from small diameter highly compliant stems to large stiff trees. Those include various types of vegetation such as grass, crops, shrubs/bushes, small trees, and large trees. Mobility measures which can be predicted include maximum safe vehicle speed along a specified path, tire slip, and fuel consumption. The ground vehicles are modeled using high-fidelity multibody dynamics models. The vegetation stems are modeled using an arrangement of thin and/or thick beam finite elements. The thin beam model uses the torsional spring beam formulation for small flexible vegetation and only includes the axial and bending beam responses. The thick beam model includes axial, bending, torsional, and shear beam responses and uses a lumped parameter beam element which connects two rigid body type nodes. The vegetation model includes the effects of normal contact and friction with the vehicle and between stems, stem breaking, and stem aerodynamic forces.
Stakeholder Perceptions of Requirements Elicitation Interviews With and Without Prototypes in a Cross-Cultural Design Setting
Authors: Coulentianos Marianna J. , Daly Shanna R. , Sienko Kathleen H. 
Published: November 2020

Abstract
Using prototypes during design requirements elicitation (RE) interviews with stakeholders can encourage stakeholder participation. Stakeholder engagement and the quality of the feedback provided can be influenced by the format of the RE interview, especially in a cross-cultural design setting. Although the selection of design practices is typically motivated by designer preferences and design outcomes, deliberate consideration of stakeholder preferences and perceptions may lead to a more nuanced understanding of when and how to best leverage particular design practices. This study investigated the influence of the number of prototypes (here, assistive devices for removing subdermal contraceptive implants) presented during RE interviews on Ghanaian stakeholder preferences. The findings revealed that most participants (n = 34, 94%) preferred the presence of one or more prototypes compared to no prototypes during the interviews because prototypes enabled participants to better understand the design space, provide accurate feedback, and evaluate ideas. Prototypes provided participants with a basis for answering designers’ questions. When they were not provided with a prototype, participants explained that they imagined a novel device concept or recalled a device from prior experiences. Further, participants preferred the use of three prototypes versus a single prototype because multiple prototypes enabled them to compare across designs and make choices. These findings suggest that designers seeking requirements-related input from stakeholders at the problem definition stage should consider using one or more prototypes, unless they are interested in collecting design ideas from stakeholders.
Early Physical Activity Adoption Predicts Longer-Term Physical Activity Among Individuals Inactive at Baseline
Authors: Unick Jessica L. , Walkup Michael P. , Miller Michael E. , Apolzan John W. , Brubaker Peter H. , Coday Mace , Hill James O. , Jakicic John M. , Middelbeek Roeland J.W. , West Delia , Wing Rena R. , _ _ 
Published: November 2020

Background: To examine the relationship between early physical activity (PA) adoption (2, 3, and 4 mo) and longer-term PA adherence (1 y) among individuals who were inactive at baseline and received a lifestyle intervention. Methods: Participants (n = 637) received weekly behavioral weight loss sessions, calorie reduction, and PA goals (50–175 min/wk progression). PA was assessed via self-reported measures at baseline, months 2 to 4, and 1 year. Results: PA at months 2 to 4 was significantly correlated with PA at 1 year (rs = .29–.35, P < .01). At all early time points, those failing to meet the prescribed PA goal (early nonadopters) engaged in significantly less PA at 1 year than those meeting the early PA goal (initial adopters). For example, using 2-month criteria, initial adopters engaged in 108.3 minutes per week more at 1 year compared with early nonadopters (P < .01) and had 2.8 times the odds (95% confidence interval, 1.9–4.2) of meeting the 1-year PA goal (≥175 min/wk, P < .01). Conclusions: Failure to achieve PA goals at 2, 3, or 4 months results in less overall PA at 1 year. Thus, PA observed as early as month 2 may be a useful indicator for identifying at-risk individuals who may benefit from more intensive PA intervention strategies.
i-CONTENT tool for assessing therapeutic quality of exercise programs employed in randomised clinical trials
Authors: Hoogeboom Thomas J , Kousemaker Martijn C , van Meeteren Nico LU , Howe Tracey , Bo Kari , Tugwell Peter , Ferreira Manuela , de Bie Rob A , van den Ende Cornelia HM , Stevens-Lapsley Jennifer E 
Published: November 2020

ObjectiveWhen appraising the quality of randomised clinical trial (RCTs) on the merits of exercise therapy, we typically limit our assessment to the quality of the methods. However, heterogeneity across studies can also be caused by differences in the quality of the exercise interventions (ie, ‘the potential effectiveness of a specific intervention given the potential target group of patients’)—a challenging concept to assess. We propose an internationally developed, consensus-based tool that aims to assess the quality of exercise therapy programmes studied in RCTs: the international Consensus on Therapeutic Exercise aNd Training (i-CONTENT) tool.MethodsForty-nine experts (from 12 different countries) in the field of physical and exercise therapy participated in a four-stage Delphi approach to develop the i-CONTENT tool: (1) item generation (Delphi round 1), (2) item selection (Delphi rounds 2 and 3), (3) item specification (focus group discussion) and (4) tool development and refinement (working group discussion and piloting).ResultsOut of the 61 items generated in the first Delphi round, consensus was reached on 17 items, resulting in seven final items that form the i-CONTENT tool: (1) patient selection; (2) qualified supervisor; (3) type and timing of outcome assessment; (4) dosage parameters (frequency, intensity, time); (5) type of exercise; (6) safety of the exercise programme and (7) adherence to the exercise programme.ConclusionThe i-CONTENT-tool is a step towards transparent assessment of the quality of exercise therapy programmes studied in RCTs, and ultimately, towards the development of future, higher quality, exercise interventions.
How sensitive are avoidable emergency department attendances to primary care quality? Retrospective observational study
Authors: Parkinson Beth , Meacock Rachel , Checkland Kath , Sutton Matt 
Published: November 2020

BackgroundImprovements in primary care quality are often proposed as a solution to rises in emergency department (ED) attendances. However, there is little agreement on what constitutes an avoidable attendance, and the relationship between primary care quality and ED demand remains poorly understood.ObjectiveTo estimate the size of the associations between primary care quality and volumes of ED attendances classified as avoidable.MethodsRetrospective observational study of all attendances at EDs in England during 2015/2016, applying three definitions of avoidable attendance. We linked practice-level counts of attendances to seven measures of primary care access, patient experience and clinical quality for 7521 practices. We used count data regressions to associate attendance counts with levels of quality. We then calculated proportions of attendances associated with levels of primary care quality below the national average.ResultsAttendance volumes were negatively related to three of the seven quality measures. Incidence rate ratios (IRRs) for all attendances associated with 10 percentage-point differences in quality were 0.987 for clinical quality and 0.987 for easy telephone access and 0.978 for ability to get an appointment. These associations were relatively stronger for narrower definitions of avoidable attendances (for the narrowest definition, IRRs=0.966, 0.976 and 0.934, respectively) but represented fewer attendances in absolute terms. 341 000 (2.4%) attendances were associated with levels of primary care quality below the national average in 2015/2016.ConclusionED attendances are sensitive to primary care quality, but magnitudes of these associations are small. Attendances are much less responsive to differences in primary care quality than indicated by estimates of the prevalence of avoidable attendances. This may explain the failure of initiatives to reduce attendances through primary care improvements.
Mutational profiling in suspected triple-negative essential thrombocythaemia using targeted next-generation sequencing in a real-world cohort
Authors: Michail Olga , McCallion Patrick , McGimpsey Julie , Hindley Andrew , Greenfield Graeme , McAllister Roisin , Feerick John , Arnold Claire , Cross Nick , Cuthbert Robert , McMullin Mary F , Catherwood Mark A 
Published: November 2020

Essential thrombocythaemia (ET) is driven by somatic mutations involving theJAK2,CALRandMPLgenes. Approximately 10% of patients lack driver mutations and are referred as ‘triple-negative’ ET (TN-ET). The diagnosis of TN-ET, however, relies on bone marrow examination that is not always performed in routine practice, and thus in the real-world setting, there are a group of cases with suspected TN-myeloproliferativeneoplasm.In this real-world cohort, patients with suspected TN-ET were initially rescreened forJAK2,CALRandMPLand then targeted next-generation sequencing (NGS) was applied.The 35 patients with suspected TN-ET had a median age at diagnosis of 43 years (range 16–79) and a follow-up of 10 years (range 2–28). The median platelet count was 758×109/L (range 479–2903). Thrombosis prior to and following diagnosis was noted in 20% and 17% of patients. Six patients wereJAK2V617F and two patients wereCALRpositive on repeat screening. NGS results showed that 24 of 27 patients harboured no mutations. Four mutations were noted in three patients.There was no evidence of clonality for the majority of patients with suspected TN-ET with targeted NGS analysis. Detection of driver mutations in those who were previously screened suggests that regular rescreening is required. This study also questions the diagnosis of TN-ET without the existence of a clonal marker.
Potential impact of eliminating illicit trade in cigarettes: a demand-side perspective
Authors: Goodchild Mark , Paul Jeremias , Iglesias Roberto , Bouw Annerie , Perucic Anne-Marie 
Published: November 2020

BackgroundThe Protocol to Eliminate Illicit Trade in Tobacco Products (the Protocol) entered into force in September 2018, and commits Parties to implement a package of measures to combat this global problem. The aim of this study is to assess the potential impact of eliminating illicit cigarettes on consumption, use and tax revenues.MethodsWe identified 36 countries where an independent (non-industry sponsored) study of the illicit cigarette market was available. We developed a conceptual framework for describing how the elimination of illicit cigarettes might impact on demand (consumption and use) and applied this framework to our sample of countries to assess the impact of eliminating illicit cigarettes across different settings.FindingsIllicit cigarettes account on average for 11.2% of the market in these 36 countries. The elimination of illicit cigarettes would reduce total cigarette consumption by 1.9% across these countries. The decrease in ‘group A’ countries—where illicit cigarettes are >15% of the market—would average 4.1%. The smoking rate would decrease by 1.0% in relative terms including by 2.2% in group A countries. Tax revenues from the legal sale of cigarettes would increase by 11.2% including by 25.1% in group A countries.ConclusionsThe illicit cigarette market reflects a complex interplay between supply and demand, with an array of different country conditions. Regardless of the situation, our study highlights the contribution that the elimination of illicit trade can make to tobacco control through demand reduction while at the same time generating significant tax revenues.
A coupled CFD–DEM investigation of internal erosion considering suspension flow
Authors: Liu Yajing , Yin Zhen-Yu , Wang Lizhong , Hong Yi 
Published: November 2020

The influence of two-phase flows containing suspension particles, which are common in nature, on internal erosion with coupling effect of clogging remains unclear. This paper presents a three-dimensional coupled computational fluid dynamics and discrete element method (CFD–DEM) analysis of internal erosion considering different concentrations of suspension C (i.e., mass of the suspended particles in unit volume of fluid) in gap-graded granular soils with different fine fraction Fc (i.e., the percentage by mass of the fine particles in the gap-graded sample). The influences of C and Fc on the erosion and clogging behavior of soils are investigated from both the macroscopic and microscopic perspectives. It is found that for gap-graded samples being underfilled with Fc = 15%, the suspension flow (i.e., influent fluid with suspending particles) decreases the cumulative eroded fine particle loss and the increasing rate of soil hydraulic conductivity due to clogging at the top of the sample. The degree of clogging is found to jointly be determined by both constriction size distribution and the suspension concentration. Clogging in a local area usually occurs with the formation of the clusters, which have a high resistance to the drag force applied by the fluid flow.