bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design of Curved Annular Diffusers
Authors: Kuchana Vinayender , Balakrishnan N. , Srinivasan Balamurugan 
Published: February 2020

Abstract
Influence of curvature distribution and area-ratio (AR) distribution on the pressure fields within the curved annular diffuser are discussed. General guidelines for end-wall contouring to control the pressure gradients on the diffuser walls are evolved and further demonstrated through computational fluid dynamics (CFD) simulations. Also, detailed guidelines for controlling the adverse pressure gradients (APG) on duct walls are presented. A geometry generation methodology (GGM) which enables both design and evaluation of curved annular diffusers based on the guidelines evolved is presented. The approach presented deals with the sensitivity of the duct performance parameters to duct wall modifications. In that sense, the work per se is not a description of an automated optimization process, but rather about the physical principles that can guide such an optimization. An aggressive diffuser design space is identified with ducts of maximum slope of 50 deg and maximum divergence angle between the outer and inner walls of 10 deg for length to inlet height ratio ranging from 1.25 to 2.5. Part of the identified design space for which the flow separation can be eliminated based on the guidelines evolved is demarcated. The need for flow control, possibly passive, is established for more aggressive designs.
Design for Clean Technology Adoption: Integration of Usage Context, User Behavior, and Technology Performance in Design
Authors: Pakravan Mohammad H. , MacCarty Nordica A. 
Published: February 2020

AbstractClean technologies aim to address climatic, environmental, and health concerns associated with their conventional counterparts. However, such technologies achieve these goals only if they are adopted by users and effectively replace conventional practices. Despite the important role that users play to accomplish these goals by making decisions whether to adopt such clean alternatives or not, currently, there is no systematic framework for quantitative integration of the behavioral motivations of users during the design process for these technologies. In this study, the theory of planned behavior (TPB) is integrated with usage-context-based design to provide a holistic approach for predicting the market share of clean versus conventional product alternatives based on users’ personal beliefs, social norms, and perception of behavioral control. Based on the mathematical linkage of the model components, technology design attributes can then be adjusted, resulting in the design of products that are more in line with users’ behavioral intentions, which can lead to higher adoption rates. The developed framework is applied in a case study of adoption of improved cookstoves in a community in Northern Uganda. Results indicate that incorporating TPB attributes into utility functions improves the prediction power of the model and that the attributes that users in the subject community prioritize in a clean cookstove are elicited through the TPB. Households’ decision-making behavior before and after a trial period suggests that design and marketing strategy should systematically integrate user’s behavioral tendencies prior to interventions to improve the outcomes of clean technology implementation projects.
Large-Stroke Constant-Force Mechanisms Utilizing Second Buckling Mode of Flexible Beams: Evaluation Metrics and Design Approach
Authors: Ma Fulei , Chen Guimin , Wang Haitian 
Published: February 2020

AbstractCompliant constant-force mechanisms (CCFMs), which provide a near constant-force output over a range of displacement, can benefit many applications. This work proposes a novel large-stroke CCFM (abbreviated as B2CCFM) that utilizes the second buckling mode of flexible beams. Two general nondimensionalized metrics, one describing the variation of output force and the other describing the operational displacement, are proposed to effectively characterize the performances of various CCFMs. Based on the general metrics, design formulas that can help designers quickly find suitable B2CCFM design for a specific application are obtained. A kinetostatic model for B2CCFM is also provided based on the chained beam constrain model to verify B2CCFM designs. An example accompanied with a prototype is presented to verify this novel CCFM and the effectiveness of the design formulas. The experimental results show that the B2CCFM example outputs a constant-force in a range as large as 45% of the beam length with variation less than 4.7%. The nondimensionalized metrics were demonstrated in comparison of several CCFMs, and the comparison results show the superior performances of B2CCFMs.
Numerical Review of Jones–Wilkins–Lee Parameters for Trinitrotoluene Explosive in Free-Air Blast
Authors: Giam Anthoni , Toh William , Tan Vincent Beng Chye 
Published: February 2020

AbstractThe analysis of complex blast scenarios typically requires advanced computational methods such as multi-material Eulerian and coupled Eulerian–Lagrangian (CEL) analysis where Jones–Wilkins–Lee (JWL) equation of state is used to model the explosive material. While multiple sets of empirical JWL parameters for trinitrotoluene (TNT) explosives have been published over the past few decades, there is also a lack of guidelines and comparative studies on their applications for the blast analysis. A standardized description of the explosive material behavior allows for a better interpretation of results from research studies involving different blast scenarios and JWL parameters. In this paper, the authors utilize numerical finite element (FE) simulations to investigate the influence of different TNT JWL parameter sets on the blast wave characteristics of a free-air blast across different scaled distances. Utilizing multi-material Eulerian analysis, a series of spherical free-air blasts involving a 100-kg TNT charge modeled with different TNT JWL parameters are conducted. The blast wave characteristics including the incident overpressure, impulse, and time of arrival (TOA) are benchmarked against the empirical-based Kingery–Bulmash air blast formulations through the conventional weapon effect calculator conwep. It was found that the incident overpressure and impulse are highly sensitive to the JWL parameters, with differences as high as 40% at smaller scaled distances, while the influence on TOA is much less significant. This paper hopes to provide a guide for future users on the appropriate JWL parameter sets to model the air blast events involving TNT explosives.
Ceramic Binder Jetting Additive Manufacturing: A Literature Review on Density
Authors: Du Wenchao , Ren Xiaorui , Pei Zhijian , Ma Chao 
Published: February 2020

AbstractThe objective of this review paper is to summarize the current status and identify the knowledge gaps in ceramic binder jetting additive manufacturing, with a particular focus on density. This paper begins with an overview of ceramic binder jetting. Then, it discusses different aspects of density, including various terminologies, measurement methods, and achieved values. Afterward, it reviews two categories of techniques to increase the part density: material preparation techniques (powder granulation, mixing powders of different sizes, using slurry feedstock, and mixing different materials) and postprocessing techniques (sintering, chemical reaction, infiltration, and isostatic pressing). Finally, it presents the knowledge gaps in the literature.
Exergy and Cost Optimization of a Two-Stage Refrigeration System Using Refrigerant R32 and R410A
Authors: Roy Ranendra , Bhowal Arup Jyoti , Mandal Bijan Kumar 
Published: February 2020

Abstract
An attempt has been made to investigate numerically a two-stage refrigeration system with flash intercooler of 50 kW cooling capacity using refrigerant R410A and its possible alternative R32. Development of the simulation model for the analysis of the system has been carried out in engineering equation solver considering the energetic, exergetic, economic, and environmental aspects. Evaporator and condenser temperatures have been varied from −50 °C to −25 °C and 40 °C to 55 °C, respectively, to carry out the simulation work. Co-efficient of performance (COP), exergetic efficiency, and plant cost rate are the three performance parameters computed in this present work. Results show that the performances of the system using R32 are comparable with those of the system using R410A. It is also observed that R32 shows slightly better thermo-economic performances at higher condenser temperature. Multi-objective optimization has also been carried out using the toolbox available for optimization in matlab to obtain the optimum performance and optimum operating conditions for both the refrigerants. Optimization results also show better thermo-economic performances of R32 over R410A though compressor discharge temperature is higher in case of R32.
Improved Physical Performance and Decreased Muscular and Oxidative Damage With Postlunch Napping After Partial Sleep Deprivation in Athletes
Authors: Romdhani Mohamed , Souissi Nizar , Chaabouni Yassine , Mahdouani Kacem , Driss Tarak , Chamari Karim , Hammouda Omar 
Published: February 2020

Purpose:To investigate the effects of napping after partial sleep deprivation (PSD) on reaction time, mood, and biochemical response to repeated-sprint exercise in athletes.Methods:Nine male judokas performed 4 test sessions in a counterbalanced and randomized order. Participants accomplished 1 control session after a normal sleep night (NSN) and 3 after PSD with (1) no nap, (2) ∼20-min nap (N20), and (3) ∼90-min nap (N90) opportunities. Test sessions included the running-based anaerobic sprint test, reaction time, Hooper index, and Epworth Sleepiness Scale. Muscle-damage biomarkers and antioxidant status were evaluated before and after exercise.Results:PSD decreased maximum (P < .001,d = 1.12), mean (P < .001,d = 1.33), and minimum (P < .001,d = 1.15) powers compared with NSN. However, N20 and N90 enhanced maximum power compared with PSD (P < .05,d = 0.54;P < .001,d = 1.06, respectively). Minimum power and mean power increased only after N90 (P < .001,d = 1.63;P < .001,d = 1.16, respectively). Epworth Sleepiness Scale increased after PSD (P < .001,d = 0.86) and decreased after N20 (P < .001,d = 1.36) and N90 (P < .001,d = 2.07). N20 reduced multiple-choice reaction time (P < .001,d = 0.61). Despite performance decrement, PSD increased postexercise aspartate aminotransferase (P < .001,d = 4.16) and decreased glutathione peroxidase (P < .001,d = 4.02) compared with NSN. However, the highest performances after N90 were accompanied with lesser aspartate aminotransferase (P < .001,d = 1.74) and higher glutathione peroxidase (P < .001,d = 0.86) compared with PSD.Conclusions:Napping could be preventive against performance degradation caused by sleep loss. A short nap opportunity could be more beneficial when the subsequent effort is brief and requires frequent decision making. However, a longer nap opportunity could be preventive against muscle and oxidative damage, even for higher performances.
Thirty-five-year trend in the prevalence of refractive error in Austrian conscripts based on 1.5 million participants
Authors: Yang Lin , Vass Clemens , Smith Lee , Juan Alfred , Waldhör Thomas 
Published: February 2020

BackgroundTo quantify the current burden of myopia and hyperopia in Austrian young men and the time trend of myopia in the past 35 years by individual and social correlates.MethodWe included data on all Austrian military conscripts from 1983 to 2017 (n=1 507 063) from six medical investigation stations. Young men provided data on education, weight and height for calculating body mass index, blood pressure and resting heart rate. Non-cycloplegic refractions were measured by an autorefractometer. Spherical equivalent was calculated by standard formula (sphere+cylinder/2, unit dioptres (D)). Myopic refractive error was defined as <−0.5 D). Hyperopic refractive error was defined as >0.5 D.ResultsThe largest burden of refractive error in Austria is myopia, which rose from 13.8% to 24.4% over 35 years, with less than 5% hyperopic population. Over time, the prevalence of myopia was constantly lower yet increased more rapidly among those with low education levels (11.4%–21.7%) compared with those with higher education (24.5%–29.6%) in all medical investigation stations. We found consistent associations of some unfavourable health indicators (underweight: ORs 1.1–1.4, higher resting heart rate: all p trend <0.001) with higher myopia prevalence, which point towards lifestyle factors playing an important role in the development of myopia.ConclusionPrimary preventive measures are needed to curb the observed trend in myopia among Austrian young men. Future research should investigate the impact of modifiable factors on myopia development and progression, particularly lifestyle factors that are dramatically shifting.
Orbital MRI versus fundus photography in the diagnosis of optic nerve hypoplasia and prediction of vision
Authors: Kruglyakova Jacqueline , Garcia-Filion Pamela , Nelson Marvin , Borchert Mark 
Published: February 2020

IntroductionIn patients with optic nerve hypoplasia (ONH), the visualisation of the optic disc can be challenging and the definitive diagnosis difficult to ascertain without fundus photography. The use of MRI for diagnosis has been reported as a diagnostic alternative with conflicting results. We retrospectively analysed a disease registry to determine the reliability of orbital MRI measurements of the optic nerve diameter to diagnose ONH, and the correlation with vision outcomes.Materials and methodsFrom a cohort of 140 patients with ONH (13% unilateral) that had reached age 5 years, we identified 43 subjects who had orbital MRI in addition to fundus photography performed prior to 2 years of age. We compared measurements of the optic nerve diameter from orbital MRI scans to the standard relative optic disc size (disc diameter/disc-macula (DD/DM) distance) by fundus photography. All patients had visual acuity tested at age 5 years. Spearman’s correlation coefficient was used to determine the correlation of orbital MRI measurements and fundus photography with the diagnosis of ONH, and with vision outcomes.ResultsRelative disc size (DD/DM)<0.35 showed 100% sensitivity and 100% specificity for the diagnostic confirmation of ONH. The optic nerve diameter measurements by orbital MRI displayed a moderate correlation (rs=0.471; p<0.001) with DD/DM and moderate sensitivity for the diagnosis of ONH. Final visual acuity correlated well with DD/DM measurements by fundus photography (rs=−0.869; p<0.001) and moderately with optic nerve diameter by orbital MRI (rs=−0.635; p<0.001).DiscussionOrbital optic nerve diameter from MRI scans has moderate reliability in diagnosing ONH and predicting vision outcomes. Fundus photography for measurements of the optic nerve size should remain the reference for diagnostic confirmation of ONH. These data further support the prognostic value of fundus photography for eventual vision outcomes in this population.
Out-of-pocket spending and financial burden among low income adults after Medicaid expansions in the United States: quasi-experimental difference-in-difference study
Authors: Gotanda Hiroshi , Jha Ashish K , Kominski Gerald F , Tsugawa Yusuke 
Published: February 2020

Abstract

Objective
To examine the association between expansion of the Medicaid program under the Affordable Care Act and changes in healthcare spending among low income adults during the first four years of the policy implementation (2014-17).

Design
Quasi-experimental difference-in-difference analysis to examine out-of-pocket spending and financial burden among low income adults after Medicaid expansions.

Setting
United States.

Participants
A nationally representative sample of individuals aged 19-64 years, with family incomes below 138% of the federal poverty level, from the 2010-17 Medical Expenditure Panel Survey.

Main outcomes and measures
Four annual healthcare spending outcomes: out-of-pocket spending; premium contributions; out-of-pocket plus premium spending; and catastrophic financial burden (defined as out-of-pocket plus premium spending exceeding 40% of post-subsistence income). P values were adjusted for multiple comparisons.

Results
37 819 adults were included in the study. Healthcare spending did not change in the first two years, but Medicaid expansions were associated with lower out-of-pocket spending (adjusted percentage change −28.0% (95% confidence interval −38.4% to −15.8%); adjusted absolute change −$122 (£93; €110); adjusted P<0.001), lower out-of-pocket plus premium spending (−29.0% (−40.5% to −15.3%); −$442; adjusted P<0.001), and lower probability of experiencing a catastrophic financial burden (adjusted percentage point change −4.7 (−7.9 to −1.4); adjusted P=0.01) in years three to four. No evidence was found to indicate that premium contributions changed after the Medicaid expansions.

Conclusion
Medicaid expansions under the Affordable Care Act were associated with lower out-of-pocket spending and a lower likelihood of catastrophic financial burden for low income adults in the third and fourth years of the act’s implementation. These findings suggest that the act has been successful nationally in improving financial risk protection against medical bills among low income adults.
Differences in prevalence and associated factors of underweight and overweight/obesity according to rural–urban residence strata among women of reproductive age in Bangladesh: evidence from a cross-sectional national survey
Authors: Hashan Mohammad Rashidul , Das Gupta Rajat , Day Brendan , Al Kibria Gulam Muhammed 
Published: February 2020

ObjectivesThis study aimed to investigate the differences in prevalence and factors influencing underweight and overweight/obesity stratified by region of residence among women of reproductive age in Bangladesh.DesignSecondary analysis of cross-sectional nationwide data.SettingThis study used Bangladesh Demographic and Health Survey 2014 data.ParticipantsA weighted sample of 16 478 women of reproductive age (15–49 years) were included in the analysis.Primary and secondary outcome measuresUsing the Asian-specific cut-off for body mass index, the primary outcome of this study was categorised as: underweight (<18.5 kg/m2), normal weight (18.5 to <23.0) kg/m2and overweight/obese (≥23.0 kg/m2) stratified according to rural–urban residence.ResultsMore than half of urban women (53%, n=2493) and one-third of rural women (33%, n=3968) were found to be overweight/obese. Around one-fifth of rural women (21%, n=2490) and almost one in eight urban women (12%, n=571) were reported as underweight. In the final multivariable analyses, increasing age, higher educational status and higher order wealth quintile, each had a significant positive association with being overweight/obese and an inverse association with being underweight. Urban unmarried women had lower odds of being overweight/obese compared with their married counterparts. Rural women who used contraceptives had significantly decreased odds (adjusted OR (AOR) 0.8, 95% CI 0.7 to 0.9) of being underweight compared with contraceptive non-users; no such association was noted in urban women. Women from Sylhet division in both urban (AOR 1.7, 95% CI 1.2 to 2.5) and rural regions (AOR 1.5, 95% CI 1.2 to 1.8) had increased odds of being underweight compared with women in Barisal division.ConclusionsThis study found association of multiple factors with both overweight/obesity and underweight among Bangladeshi women of reproductive age. Public health programmes in Bangladesh aiming to prevent the double burden of malnutrition should focus these factors through comprehensive public awareness and cost-effective operational health interventions.
Does the sampling instrument influence corneal culture outcome in patients with infectious keratitis? A retrospective study comparing cotton tipped applicator with knife blade
Authors: Sagerfors Susanna , Ejdervik-Lindblad Birgitta , Söderquist Bo 
Published: February 2020

ObjectiveThis study aimed to compare the efficacy of a cotton tipped applicator and a knife blade in obtaining corneal samples in patients with infectious keratitis.Methods and analysisThis is a retrospective cohort study of patients with suspected infectious keratitis during 2004–2014. Samples for corneal culture were obtained by a cotton tipped applicator and a knife blade, and directly inoculated on GC agar, blood agar and Sabouraud agar.ResultsIn all, 355 patients were included. Corneal sampling by cotton tipped applicator yielded a significantly higher rate of patients with positive corneal culture, 156/355 (43.9%), compared with knife blade, 111/355 (31.3%) (p<0.001). On a patient level, the culture results obtained by the cotton tipped applicator and the knife blade were identical in 269/355 (76%) of the patients. The overall agreement between the two instruments on microbial level was 0.66 (Cohen’s kappa 95% CI 0.60 to 0.72).ConclusionCorneal sampling by cotton tipped applicator generated a higher rate of positive corneal cultures and a higher proportion of isolated microbes than by knife blade. Future studies with randomised sampling order are needed to establish which instrument, cotton tipped applicator or knife blade, is the most effective in sampling microbes for direct inoculation in patients with infectious keratitis.
Barbell back squat: how do resistance bands affect muscle activation and knee kinematics?
Authors: Reece Madeleine B , Arnold Graham P , Nasir Sadiq , Wang Weijie W , Abboud Rami 
Published: February 2020

ObjectivesThis study aimed to determine whether looped resistance bands affect knee kinematics and lower body muscle activation during the barbell back squat.MethodsTwenty-six healthy participants (13 female, 13 male) calculated their one repetition maximum (RM) prior to data collection. Each participant performed three squats at both 80% and 40% 1RM wearing a light resistance band, an extra-heavy resistance band and no resistance band.Vicon 3D motion analysis cameras were used to collect the kinematic data, and Delsys Trigno Lab wireless electromyography (EMG) system was used to measure vastus medialis, vastus lateralis, gluteus maximus, gluteus medius and biceps femoris muscle activity. Peak knee flexion angle, peak knee valgus angle and maximum tibial rotation values were examined. Peak EMG values were also analysed after being normalised and expressed as a percentage of maximum voluntary contraction (MVC).ResultsGluteus maximus (GM) activity is significantly increased when a resistance band is used during squatting. However, squatting with a resistance band is detrimental to knee kinematics as it leads to an increase in knee valgus angle and maximum tibial rotation angle. A direct correlation is recorded between an increase in resistance and an increase in these two angles.ConclusionsSquatting with resistance bands is likely to increase the risk of knee injury. Coaches and clinicians who already implement this technique are advised to remove resistance band squats from training and rehabilitation programmes. Further research evaluating the long-term effects of using resistance bands during the barbell back squat should be considered.