bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rack-Level Thermosyphon Cooling and Vapor-Compression Driven Heat Recovery: Condenser Model
Authors: Khalid Rehan , Amalfi Raffaele Luca , Wemhoff Aaron P. 
Published: November 2021

Abstract
This paper is focused on the modeling of a brazed plate heat exchanger (BPHE) for a novel in-rack cooling loop coupled with heat recovery capability for enhanced thermal management of datacenters. In the proposed technology, the BPHE is acting as a condenser, and the model presented in this study can be applied in either the cooling loop or vapor recompression loop. Thus, the primary fluid enters as either superheated (in the vapor recompression loop) or saturated vapor (in the cooling loop), while the secondary fluid enters as a sub-cooled liquid. The model augments an existing technique from the open literature and is applied to condensation of a low-pressure refrigerant R245fa. The model assumes a two-fluid heat exchanger with R245fa and water as the primary and secondary fluids, respectively, flowing in counterflow configuration; however, the model can also handle parallel flow configuration. The 2-D model divides the heat exchanger geometry into a discrete number of slices to analyze heat transfer and pressure drops (including static, momentum and frictional losses) of both fluids, which are used to predict the exit temperature and pressure of both fluids. The model predicts the exchanger duty based on the local energy balance. The predicted values of fluid output properties (secondary fluid temperature and pressure, and primary fluid vapor quality and pressure) along with heat exchanger duty show good agreement when compared against a commercial software.
Effect of Aging on the Properties of Intermetallic Layers in SAC+Bi Solder Joints
Authors: Haq Mohammad Ashraful , Hoque Mohd Aminul , Suhling Jeffrey C. , Lall Pradeep 
Published: November 2021

Abstract
A major problem faced by electronic packaging industries is the poor reliability of lead free solder joints. One of the most common methods utilized to tackle this problem is by doping the alloy with other elements, especially bismuth. Researches have shown Bismuth doped solder joints to mostly fail near the Intermetallic (IMC) layer rather than the bulk of the solder joint as commonly observed in traditional SAC305 solder joints. An understanding of the properties of this IMC layer would thus provide better solutions on improving the reliability of bismuth doped solder joints. In this study, the authors have used three different lead free solders doped with 1%, 2% and 3% bismuth. Joints of these alloys were created on copper substrates. The joints were then polished to clearly expose the IMC layers. These joints were then aged at 125 °C for 0, 1, 2, 5 and 10 days. For each aging condition, the elastic modulus and the hardness of the IMC layers were evaluated using a nanoindenter. The IMC layer thickness and the chemical composition of the IMC layers were also determined for each alloy at every aging condition using Scanning Electron Microscopy (SEM) and EDS. The results from this study will give a better idea on how the percentage of bismuth content in lead free solder affects the IMC layer properties and the overall reliability of the solder joints.
Performance Analysis of Micro-Raman Spectroscopy Models for Thermal Conductivity Calculation
Authors: Meydando Taher , Donmezer Nazli 
Published: November 2021

Abstract
Micro-Raman spectroscopy has been preferred recently to measure the thermal conductivity of thin-films due to its nondestructive and non-contact nature. However, the thermal size effects originating from both localized heat generation from Raman laser and phonon scattering at boundaries may cause erroneous estimation of the thermal conductivities with the current approach. In this study, the gray phonon Boltzmann transport equation (BTE) is solved to improve the results of micro-Raman thermal conductivity measurements. Due to the frequency independence of single phonon mode in the gray BTE model, our method stays ahead of most theoretical methods in calculation time while giving adequate agreement with the literature data. The improved thermal conductivities are evaluated at various laser powers and focal lengths. Subsequently, the values of thermal conductivities are compared with a simple slab model in which the deduction of thermal conductivity in sub-micron thicknesses is calculated using reduced heat flux through the slab resulting from phonon directional energy densities. The results show that subsequent errors are present in measuring the thermal conductivity of relatively thick, thin films with this technique which are noticed by comparing with the simple slab model. Finally, a virtual micro-Raman thermography experiment is developed, and its validity is verified by the same slab model.
Lightweight, Cost-Effective Power Modules Using Polymer Baseplates With Integrated Microconvective Cooling
Authors: Earley David , Mizerak Jordan , May Chris , Malouin Bernard 
Published: November 2021

Abstract
The advent of wide bandgap (WBG) semiconductors, such as silicon carbide (SiC) and gallium nitride (GaN), has enabled power electronics with increasing current densities and switching frequencies. A byproduct of these improved electrical characteristics is an increase in thermal power density. Indeed, the full capability of WBG semiconductors may be underutilized if the thermal management solution cannot keep pace with the device heat generation density. Further, as many power electronics devices are integrated into a power module form factor containing a metal baseplate to allow heat spreading from high heat fluxes generated at semiconductor dies, system integrators are often sensitive to cost and weight considerations in building up systems with traditional power module designs.
In this paper, a polymer baseplate with integrated microconvective cooling (PBIMC) is designed and built as a low-weight, cost-effective alternative for metal baseplates on power module devices. Microconvective cooling, featuring optimized single-phase impingement cooling and effluent fluid flow control, provides high power density heat removal from localized heat flux areas in power module packages to obviate the need for a metal heat spreader. Thermal performance of the PBIMC is tested on a thermal test vehicle representative of an IGBT power module to power densities up to 200W/cm2 and compared to an off the shelf minichannel cold plate. The PBIMC achieved equivalent per IGBT case-to-fluid areal thermal resistances of 0.15 K-cm2/W, a 69% decrease compared to the baseline cold plate. Additionally, thermal crosstalk was shown to be reduced by up to 89% when moving from the cold plate to the PBIMC, demonstrating potential advantages in utilizing thermal management techniques that do not feature heat spreading. The prototype-level polymer baseplates showed a &gt; 80% decrease in weight compared to a traditional power module metal baseplate. The study concludes that the PBIMC shows promise as a solution for high current density power electronics in weight sensitive applications, while providing opportunities for cost savings.
Printed Flexible LC Filter Using Additive Micro-Dispensing With Silver Conductive Paste and ECA for Component Attachment
Authors: Lall Pradeep , Narangaparambil Jinesh , Schulze Kyle , Miller Scott 
Published: November 2021

Abstract
Filters are used in a variety of signal processing applications in commercial and defense electronics. The use of additively printed electronics in high-frequency applications requires an understanding of the process-performance interactions versus frequency of operation. Assembly of filters for integration into existing circuits requires additively printed metallization traces in addition to component attachment methods. Comparison of frequency response of the additively-printed filtering circuits vs conventional filters subtractively-fabricated on rigid substrates is needed to determine the performance parity of additive fabrication methods. In this paper, a micro-dispensing device is used to print conductive traces and electrically conductive adhesive (ECA) pads for the attachment of components. The effect of different print parameters on the width and height of the trace has been studied. Mechanical and electrical properties also play an important role in the study of different sintering conditions. Optimized parameters from the printing process and sintering analysis are used to print and compare commercially available LC filter circuitry using the Bode plot.
Life-Assessment for Thin Flexible Batteries Under U-Flex-to-Install and Dynamic Folding
Authors: Lall Pradeep , Soni Ved , Miller Scott 
Published: November 2021

Abstract
The growing need for wearable devices, fitness accessories and biomedical equipment has led to the upsurge in research and development of thin flexible battery research and development. The current state of art wearable electronics products being developed in several fields require installation of power sources in different configurations and at times require the battery to undergo mechanical folding during product operation. This requires the product batteries to robustly withstand the imposed mechanical stresses during use along with the other desirable characteristics attributed to the power source such as high C-rate capability, high capacity and low capacity degradation rate. Works that explore the effects of static and dynamic folding on li-ion power sources is limited and oftentimes doesn’t adhere to definite test protocols resulting in non-standardized experimental data that can’t be applied to real-life product scenarios. Specifically, the effect of fold diameter on the battery state of health degradation when subjected to both static and dynamic folding is not yet completely explored. Present study aims to address this gap in the literature by investigating the effect of varying the fold diameter is both static (U-flex-to-install) and dynamic (dynamic U-fold) tests. Four different values of fold diameters have been chosen for experimentation and to study its effect during the aforementioned tests. Multiple samples have been tested for a given test condition so as to generate high fidelity data. Ultimately, a regression model developed previously has been augmented with the results generated in the current study.
Thermal Transport Across Al-(AlxGa1-x)2O3 and Al-Ga2O3 Interfaces
Authors: Shi Jingjing , Krishnan Anusha , Bhuiyan A. F. M. Anhar Uddin , Koh Yee Rui , Huynh Kenny , Mauze Akhil , Mu Sai , Foley Brian M. , Ahmad Habib , Itoh Takeki , Zhang Yuewei , Yuan Chao , Kim Samuel , Doolittle W. Alan , Van de Walle Chris , Speck James S. , Goorsky Mark , Hopkins Patrick , Zhao Hongping , Graham Samuel 
Published: November 2021

Abstract
(AlxGa1−x)2O3 and Ga2O3 are promising wide bandgap semiconductors for application in power electronics and radio frequency devices because of their exceptional electrical transport properties. However, the heat dissipation in these devices will be limited by the ultra-low thermal conductivity of (AlxGa1−x)2O3 and Ga2O3. Previous studies showed that these devices could achieve high power density with double-sided or top-side cooling strategies. Therefore, the thermal transport across metal-(AlxGa1−x)2O3 and metal-Ga2O3 contacts is important, since heat will be conducted through the metal-semiconductor interface as a preferred pathway to extract heat from the devices. In this work, we study the thermal transport across Al-(AlxGa1−x)2O3 and Al-Ga2O3 interfaces with an (010) orientation for the semiconductors. We have applied thermal and material characterization (time-domain thermoreflectance (TDTR) and high-resolution transmission electron microscopy (HRTEM) together with theoretical approaches to understand the interfacial thermal transport at Al-(AlxGa1−x)2O3 and AlGa2O3 contacts. It is found that for different growth methods, the highest TBC at Al-Ga2O3 interface occurs with molecular beam epitaxy (MBE) deposition of the Al on Ga2O3. However, the experimentally measured TBC at E-beam evaporated Al interfaces is much lower than that at the MBE grown Al interfaces. The measured values are also much lower than theoretical predictions, and it is related to the interfacial chemical reactions that occur at the interfaces. The effect of Al composition on interfacial thermal transport at Al/(AlxGa1−x)2O3 interface is also studied. It is found that the TBC at the E-beam evaporated Al/(AlxGa1−x)2O3 interface is very close to that of the E-beam evaporated Al-Ga2O3 interface at different temperatures in the ternary alloy studied.
Can We Modify Maximal Speed Running Posture? Implications for Performance and Hamstring Injury Management
Authors: Mendiguchia Jurdan , Castaño-Zambudio Adrián , Jiménez-Reyes Pedro , Morin Jean–Benoît , Edouard Pascal , Conceição Filipe , Tawiah-Dodoo Jonas , Colyer Steffi L. 
Published: November 2021

Purpose: Sprint kinematics have been linked to hamstring injury and performance. This study aimed to examine if a specific 6-week multimodal intervention, combining lumbopelvic control and unning technique exercises, induced changes in pelvis and lower-limb kinematics at maximal speed and improved sprint performance. Methods: Healthy amateur athletes were assigned to a control or intervention group (IG). A sprint test with 3-dimensional kinematic measurements was performed before (PRE) and after (POST) 6 weeks of training. The IG program included 3 weekly sessions integrating coaching, strength and conditioning, and physical therapy approaches (eg, manual therapy, mobility, lumbopelvic control, strength and sprint “front-side mechanics”-oriented drills). Results: Analyses of variance showed no between-group differences at PRE. At POST, intragroup analyses showed PRE–POST differences for the pelvic (sagittal and frontal planes) and thigh kinematics and improved sprint performance (split times) for the IG only. Specifically, IG showed (1) a lower anterior pelvic tilt during the late swing phase, (2) greater pelvic obliquity on the free-leg side during the early swing phase, (3) higher vertical position of the front-leg knee, (4) an increase in thigh angular velocity and thigh retraction velocity, (5) lower between-knees distance at initial contact, and (6) a shorter ground contact duration. The intergroup analysis revealed disparate effects (possibly to very likely) in the most relevant variables investigated. Conclusion: The 6-week multimodal training program induced clear pelvic and lower-limb kinematic changes during maximal speed sprinting. These alterations may collectively be associated with reduced risk of muscle strain and were concomitant with significant sprint performance improvement.
Upper-Limb Force–Time Characteristics Determine Serve Velocity in Competition Tennis Players
Authors: Baiget Ernest , Colomar Joshua , Corbi Francisco 
Published: November 2021

Purpose: (1) To analyze the associations between serve velocity (SV) and various single-joint upper-limb isometric force–time curve parameters, (2) to develop a prediction model based on the relationship between these variables, and (3) to determine whether these factors are capable of discriminating between tennis players with different SV performances. Method: A total of 17 high-performance tennis players performed 8 isometric tests of joints and movements included in the serve kinetic chain (wrist and elbow flexion [EF] and extension; shoulder flexion [SHF] and extension [SHE], internal [SHIR] and external rotation). Isometric force (IF), rate of force development (RFD), and impulse (IMP) at different time intervals (0–250 ms) were obtained for analysis. Results: Significant (P < .05 to P < .01) and moderate to very large correlations were found between SV and isometric force (IF), RFD and impulse (IMP) at different time intervals in all joint positions tested (except for the EF). Stepwise multiple regression analysis highlighted the importance of RFD in the SHIR from 0 to 50 milliseconds and isometric force (IF) in the SHF at 250 milliseconds on SV performance. Moreover, the discriminant analyses established SHIR RFD from 0 to 30 milliseconds as the most important factor discriminating players with different serve performances. Conclusions: Force–time parameters in upper-limb joints involved in the serve moderate to very largely influence SV. Findings suggest that the capability to develop force in short periods of time (<250 ms), especially in the shoulder joint, seems relevant to develop high SV in competition tennis players.
Prehospital delay is an important risk factor for mortality in community-acquired bloodstream infection (CA-BSI): a matched case–control study
Authors: Holmbom Martin , Andersson Maria , Berg Sören , Eklund Dan , Sobczynski Pernilla , Wilhelms Daniel , Moberg Anna , Fredrikson Mats , Balkhed Åse Östholm , Hanberger Håkan 
Published: November 2021

ObjectivesThe aim of this study was to identify prehospital and early hospital risk factors associated with 30-day mortality in patients with blood culture-confirmed community-acquired bloodstream infection (CA-BSI) in Sweden.MethodsA retrospective case–control study of 1624 patients with CA-BSI (2015–2016), 195 non-survivors satisfying the inclusion criteria were matched 1:1 with 195 survivors for age, gender and microorganism. All forms of contact with a healthcare provider for symptoms of infection within 7 days prior CA-BSI episode were registered. Logistic regression was used to analyse risk factors for 30-day all-cause mortality.ResultsOf the 390 patients, 61% (115 non-survivors and 121 survivors) sought prehospital contact. The median time from first prehospital contact till hospital admission was 13 hours (6–52) for non-survivors and 7 hours (3–24) for survivors (p<0.01). Several risk factors for 30-day all-cause mortality were identified: prehospital delay OR=1.26 (95% CI: 1.07 to 1.47), p<0.01; severity of illness (Sequential Organ Failure Assessment score) OR=1.60 (95% CI: 1.40 to 1.83), p<0.01; comorbidity score (updated Charlson Index) OR=1.13 (95% CI: 1.05 to 1.22), p<0.01 and inadequate empirical antimicrobial therapy OR=3.92 (95% CI: 1.64 to 9.33), p<0.01. In a multivariable model, prehospital delay >24 hours from first contact remained an important risk factor for 30-day all-cause mortality due to CA-BSI OR=6.17 (95% CI: 2.19 to 17.38), p<0.01.ConclusionPrehospital delay and inappropriate empirical antibiotic therapy were found to be important risk factors for 30-day all-cause mortality associated with CA-BSI. Increased awareness and earlier detection of BSI in prehospital and early hospital care is critical for rapid initiation of adequate management and antibiotic treatment.
Investigating the impact of patient-centred labels on comprehension of medication dosing: a randomised controlled trial
Authors: Saleem Ahsan , Woodruff Gemma , Steadman Kathryn , La Caze Adam 
Published: November 2021

ObjectiveThis study aims to implement a version of patient-centred labels (PCL) consistent with current labelling practice in Australia; assess the effectiveness of PCL in relation to the proportion of participants that correctly comprehend dosing instructions, and explore the proportion of correct comprehension of PCL in participants with both low and high health literacy.DesignRandomised controlled trial.SettingA large tertiary care hospital in Brisbane, Queensland, Australia.Participants121 participants with a majority born in Australia (65.3%), New Zealand (14.0%), the UK (6.6%) and Ireland (2.5%).InterventionParticipants were randomly assigned to either a panel of three PCL (n=61) or three standard labels (n=60) and asked to comprehend their assigned panel of labels.Outcome measuresDifference in the proportion of participants that correctly comprehend dosing instructions provided on PCL compared with standard labels. The two-proportion test was used to measure the impact of PCL on the proportion of participants correctly comprehending dosing instructions.ResultsA greater proportion of participants were able to accurately comprehend PCL compared with standard labels. The proportion of participants who were able to correctly comprehend dose instructions provided on all three labels was significantly higher in the group that received PCL; 23.3% standard vs 83.6% PCL, p<0.001. The effect was observed in both low and high health literacy participants. The proportion of participants with accurate label comprehension was higher in participants with low Newest Vital Signs scores (8.3% standard vs 85.7% PCL, p<0.001) and low Rapid Estimate of Adult Literacy in Medicine scores (10.5% standard vs 96.0% PCL, p<0.001) who received PCL.ConclusionThis study supports the use of PCL in Australian pharmacy practice. PCL provide simple, clear and explicit dosing instructions to patients. Implementing PCL may reduce the risk of misinterpreting dosing instructions by patients and improve quality use of medicines.Trial registration numberACTRN12621000083897; Results.
Association between the number of visual fields and the accuracy of future prediction in eyes with retinitis pigmentosa
Authors: Asaoka Ryo , Oishi Akio , Fujino Yuri , Murata Hiroshi , Azuma Keiko , Miyata Manabu , Obata Ryo , Inoue Tatsuya 
Published: November 2021

PurposeTo evaluate the minimum number of visual fields (VFs) required to precisely predict future VFs in eyes with retinitis pigmentosa (RP).MethodsA series of 12 VFs (Humphrey Field Analyzer 10–2 test (8.9 years in average) were analysed from 102 eyes of 52 patients with RP. The absolute error to predict the 12th VF using the prior 11 VFs was calculated in a pointwise manner, using the linear regression, and the 95% CI range was determined. Then, using 3–10 initial VFs, next VFs (4th to 11th VFs, respectively) were also predicted. The minimum number of VFs required for the mean absolute prediction error to reach the 95% CI was identified. Similar analyses were iterated for the second and third next VF predictions. Similar analyses were conducted using mean deviation (MD).ResultsIn the pointwise analysis, the minimum number of VFs required to reach the 95% CI for the 12th VF was five (first and second next VF predictions) and six (third next VF prediction). For the MD analysis, three (first and second next VF predictions) and four (third next VF prediction) VFs were required to reach 95% CI for the 12th VF.ConclusionsThe minimum number of VFs required to obtain accurate predictions of the future VF was five or six in the pointwise analysis and three or four in the analysis with MD.