bluuebunny/crossref_metadata_2025 huggingface dataset:
In Mistral's footsteps: “The Other” (1954) as the substrate poem for contemporary Chilean women poets
Authors: Fernández Melleda Bárbara
Published: September 2020

This study proposes that Gabriela Mistral's poem “The Other” (1954) is a work that has inspired many contemporary Chilean women poets. Evidence from three poetry collections—Alejandra Del Río's Written in Braille (1999), Marina Arrate's Uranium (1999), and Malú Urriola's Butterfly Stroke (2007)—connect directly to Mistral's proposal in “The Other.” These contemporary poets take up the psychic unfolding of the speaker in that poem to vindicate the woman that in Mistral's work was annihilated. These three contemporary poets prove that now is time for women to freely express themselves and their desires through the written word, subverting traditional patriarchal discourse.
Responses of humpback whales to a changing climate in the Southern Hemisphere: Priorities for research efforts
Authors: Meynecke Jan‐Olaf , Seyboth Elisa , De Bie Jasper , Menzel Barraqueta Jan‐Lukas , Chama Abdoulkadri , Prakash Dey Subhra , Lee Serena Blyth , Tulloch Vivitskaia , Vichi Marcello , Findlay Ken , Roychoudhury Alakendra Narayan , Mackey Brendan
Published: September 2020

Globally, baleen whales were severely depleted by historic whaling. Recovering populations have been observed to alter their behaviour. These changes have been attributed to climate change in some cases and raise concerns over the successful recovery of baleen whale populations. Current data‐driven statistical habitat and behavioural models have proven useful for addressing questions of whale distribution changes within their limitations. Given observed changes in oceanic conditions, a new approach to managing baleen whale population recovery is necessary. Model predictions of future whale movements and distributions under climate change scenarios are vital to enable adequate conservation management. This paper presents a new perspective on understanding the impacts of climate change on humpback whales, arguing the need for a system‐based multidisciplinary research approach. Our approach includes coupled, mechanistic models based upon robust ecological principles, and integrates key physical, biogeochemical, biological and ecological modules to address long‐term changes associated with climate change. To illustrate the need for this system‐based multidisciplinary approach, we focus on Southern Hemisphere humpback whales, the recovery of which may be impacted by rapid changes in habitat conditions brought about by anthropogenic climate change.
Abundance, survival, and annual rate of change of Cuvier's beaked whales (Ziphius cavirostris) on a Navy sonar range
Authors: Curtis K. Alexandra , Falcone Erin A. , Schorr Gregory S. , Moore Jeffrey E. , Moretti David J. , Barlow Jay , Keene Erin
Published: September 2020

Bayesian mark‐recapture estimates of survival, abundance, and trend are reported for Cuvier's beaked whales (Ziphius cavirostris) using a Navy training range off southern California. The deep‐diving beaked whale family is exceptionally vulnerable to mid‐frequency active sonar (MFAS), which has been implicated in mass strandings and altered foraging behavior. Extremely low sighting probabilities impede studies of population‐level impacts of MFAS on beaked whales. The San Nicolas Basin hosts a Navy training range subject to frequent MFAS use and attracts high densities of Z. cavirostris. An 11‐year (2007–2018) photo‐identification program leveraged automated acoustic detection and location capabilities on the range's 1,800‐km2 hydrophone array to enhance capture probability. Estimated population parameters for Z. cavirostris using the range included mean (90% credibility intervals) apparent annual survival of 0.950 (0.899–0.986), annual number of individuals as 121 (71–219), and annual rate of change of −0.8% (−5.6%–4.1%). Simulations show the probability of detecting abundance changes is currently low, but can be greatly improved through continued monitoring and increased effort. Complementary data collection on habitat use and demographic rates in San Nicolas and surrounding basins is also essential to relating direct effects of MFAS use to changes in vital rates and broader population outcomes.
Epidemiology, clinical features, diagnosis and treatment of cerebral mucormycosis in diabetic patients: A systematic review of case reports and case series
Authors: Chegini Zahra , Didehdar Mojtaba , Khoshbayan Amin , Rajaeih Shahin , Salehi Mohammadreza , Shariati Aref
Published: September 2020

Background

Patients with diabetes are known as an important high‐risk group for cerebral mucormycosis (CM).

Method

We conducted a structured search using PubMed/MEDLINE to collect both case reports and case series case (ie including at least two patients) onto CM in diabetic patient published between 2000 and March 2020.

Results

Forty‐five reports of individual cases and eighteen case series articles were included. India accounted for the largest share of reports with 37.7% and 38.8% of individual cases and case series, respectively. Mortality ranged from 0% to 100% in the case series. The overall mortality in the individual cases was 46.3%, and 64.2% of deaths were reported in patients with ketoacidosis diabetes. Facial swelling (53.3%), headache (44.4%), loss of vision (35.5%) and ophthalmoplegia (35.5%) were the most frequently reported clinical symptoms. In all patients except 4 (91.1%), CM was treated surgically; however, in many cases (42%), despite the use of surgery, death occurred. Amphotericin B deoxycholate (AMB) and lipid‐based AMB (LAMB) were used as the first lines of treatment for all patients; however, posaconazole, echinocandins, hyperbaric oxygen therapy (HBOT) and deferasirox were used in combination for a number of patients. Posaconazole has been shown to have positive therapeutic effect; however, posaconazole, LAMB and HBOT are not commonly used in low‐income and health‐challenged countries.

Conclusion

Cerebral mucormycosis is a rapidly progressive infection in diabetic patients and carries immense morbidity despite early diagnosis and treatment. Low‐income countries have had the highest number of reports of the disease in recent years, indicating the need to control diabetes in these countries.
Nodakenin alleviates renal ischaemia‐reperfusion injury via inhibiting reactive oxygen species‐induced NLRP3 inflammasome activation
Authors: Liao Yuan , Lin Xiao , Li Jianchun , Tan Ruizhi , Zhong Xia , Wang Li
Published: September 2020

Background

Acute kidney injury (AKI) is a vital contributor to chronic kidney disease and limited therapeutic options are existed to preserve the renal injury. The research presented here investigated the protective effect of nodakenin against AKI and the underlying mechanism.

Methods

The effect of nodakenin was investigated in ischaemia reperfusion‐induced renal injury (IRI) of AKI mice and hypoxia‐treated primary renal tubular cells. Briefly, renal functions including creatinine and urea nitrogen were determined and mechanisms associated inflammation were investigated by the advantage of immunohistochemistry, western blot, RT‐PCR and flow cytometry.

Results

Deterioration of renal functions including and creatinine, urea nitrogen and tubular necrosis were observed in IRI‐AKI model. In contrast, nodakenin strikingly alleviated the deterioration of creatinine, urea nitrogen and tubular necrosis when compared with IRI model. Moreover, nodakenin could significantly inhibit the expression of pro‐inflammatory cytokines including interleukin (IL)‐1β, IL‐6 and tumour necrosis factor‐α both in hypoxia‐treated primary renal tubular cells and in AKI model. Mechanistic studies revealed that nodakenin dramatically suppressed the production of reactive oxygen species and subsequent NLPR3 inflammasome activation.

Conclusion

In summary, these findings provided a solid evidence base and a new drug option for the treatment of AKI.
Treatment of Chronic Anterior Shoulder Dislocation by Coracoid Osteotomy with or without Bristow–Latarjet Procedure
Authors: Yang Yong‐liang , Li Qing‐hu , Zhang Qi , Jia Hong‐lei , Wang Bo‐min , Dong Jin‐lei , Zhou Dong‐sheng , Wang Xiao‐mei , Li Lian‐xin
Published: September 2020

Objective

To investigate the clinical efficacy and outcomes of the coracoid osteotomy with or without Bristow–Latarjet procedures in the treatment of chronic anterior shoulder dislocation (CASD).

Methods

Between January 2013 and January 2019, 20 shoulders of 18 patients who were diagnosed with chronic anterior dislocation and underwent open reduction in our trauma center were retrospectively studied. Open coracoid osteotomy with Bristow–Latarjet procedures were performed on 16 shoulders and open coracoid osteotomy without Bristow–Latarjet procedures were performed on four shoulders. Open coracoid osteotomy with or without Bristow–Latarjet procedures were chosen on the basis of the stability of the shoulder after reduction. Outcomes were assessed preoperatively and postoperatively with the visual analog scale (VAS) for pain, the American Shoulder and Elbow Surgeons (ASES) score, the University of California Los Angeles (UCLA) shoulder rating scale, and the range of motion (ROM) for shoulder activity.

Results

There were three males and 15 females with an average age of 60.94 ± 2.69 years. The time between dislocation and treatment ranged from 21 to 240 days with an average of 73.3 ± 14.4 days. All patients were available for a mean follow‐up of 15.2 ± 4.3 months. No procedure‐related death or incision‐related superficial or deep tissue infection was identified in all cases. No iatrogenic neurovascular injuries or fractures were found in this study. At the time of 12 months follow‐up, the range of motion and the shoulder functional evaluation (VAS [P < 0.001], ASES [P < 0.001], and UCLA score [P < 0.001]) in patients who underwent Bristow–Latarjet procedures were significantly improved. Subluxation after surgical procedure was found and confirmed in one patient and this patient refused to undergo revision surgery. According to the Samilson and Prieto classification system, 16 shoulders were assessed as grade 0, three shoulders were grade 1, one shoulder was grade 2.

Conclusions

Coracoid osteotomy with or without Bristow–Latarjet procedure yielded an acceptable clinical result in this study. This method has the advantages of enlarging the exposure of surgical field, assisting reduction of shoulder, and convenient conversion to Bristow–Latarjet procedure. It is an efficient and reliable method for treatment of chronic anterior shoulder dislocation.

A 69‐year‐old woman diagnosed with right chronic anterior shoulder dislocation with large Hill–Sachs lesion. The latarjet procedure with remplissage technique was applied for this patient.
Diagnosis of Sacroiliac Joint Pain: Predictive Value of Three Diagnostic Clinical Tests
Authors: Mekhail Nagy , Saweris Youssef , Sue Mehanny Diana , Makarova Natalya , Guirguis Maged , Costandi Shrif
Published: September 2020

Introduction

To date, there have been no acceptable and accurate diagnostic criteria or standards of care for the management of sacroiliac joint (SIJ) pain. Several studies have yielded different contributions of clinical presentation, history, and physical examination in the diagnosis of SIJ pain. Our goal in this study was to assess the sensitivity and specificity of the diagnostic clinical tests and their predictive value in accurately diagnosing SIJ pain.

Methodology

Upon enrolling 200 eligible patients with SIJ pain as their primary diagnosis, they were re‐evaluated and their verbal rating scale (VRS) pain scores and demographic data were obtained. Thereafter, three SIJ diagnostic tests were performed: the thigh thrust test, the Patrick test, and a modified version of the Gaenslen test that is referred to as the Mekhail test. Subsequently, the patients were taken to the procedure room to undergo SIJ injection, for which a confirmative result was ≥50% pain relief. The physicians performing the procedure were blinded of the results of the 3 tests performed. Results from the 3 tests were incorporated with the procedure results, from which we drew statistical and medical conclusions determining their predictive value and degree of aid to physicians in diagnosing SIJ pain.

Results

We found that the cumulative effect of adding simultaneous tests increased the sensitivity of the testing but decreased the specificity, which generates a powerful screening tool. The combination of the Patrick and Mekhail tests demonstrated the best accuracy, with 94% sensitivity, 17% specificity, 81% positive predictive value, and 44% negative predictive value. The Patrick test was better than other tests for differentiating patients with SIJ pain from those with non‐SIJ pain. No combination yielded both significant sensitivity and specificity. Generally, the overall predictive value of any of the tests on their own or their combination did not vary significantly from the predictive value of baseline demographics, including pre‐injection pain score and pain referral diagram.

Conclusion

In conclusion, our study results were similar to those of previous investigators who found that physical examination plays a limited role in diagnosing SIJ pain. Specifically, we found that the clinical tests and/or their combinations added no significant predictive capacity compared to patients’ baseline characteristics in predicting the response to diagnostic SIJ injection, albeit the combination of the Mekhail and Patrick tests yielded high sensitivity (94%), making them viable for consecutive screening, possibly reducing the unnecessary costs of diagnostic SIJ injection procedures.
The risks and benefits of initiating change at work: Social consequences for proactive employees who take charge
Authors: Zhang Melody Jun , Law Kenneth S. , Wang Lin
Published: September 2020

We study employee taking charge behavior in a team context and investigate how it influences social consequences in work teams. Drawing on the person perception perspective and the warmth–competence framework, we develop a theoretical model outlining how coworkers view and react to those team members who take charge more at work. We conducted two studies to test our model. Using a three‐wave, multisource study with a round‐robin design (Study 1), we find that members who take charge relatively more in their work teams tend to be perceived as more competent and are more likely to emerge as informal leaders; however, they are also likely to be seen as less warm and receive less coworker support, especially in teams with a low initiative climate. In a follow‐up vignette experimental study (Study 2), we replicate the results in a more controlled setting and expand our understanding of the social consequences for employee taking charge behavior. We discuss the theoretical and practical implications of these results.
The impact of occlusive vs non‐occlusive application of 5‐aminolevulinic acid (BF‐200 ALA) on the efficacy and tolerability of photodynamic therapy for actinic keratosis on the scalp and face: A prospective within‐patient comparison trial
Authors: Meierhofer C. , Silic K. , Urban M. V. , Tanew Adrian , Radakovic Sonja
Published: September 2020

Background

Photodynamic therapy (PDT) is an effective treatment for actinic keratoses (AK). PDT is usually performed with occlusion of the photosensitizer prior to subsequent illumination.

Objectives

This study aimed to compare the efficacy and tolerability of occlusive versus non‐occlusive application of a 5‐aminolevulinic gel (BT‐200 ALA) for PDT of multiple AK on the scalp or face.

Methods

Prospective, investigator‐blinded, within‐patient comparison study on 45 patients. PDT with occlusion of ALA was performed in a target area on one randomized side of the scalp or face. One week later a contralateral target area received the same treatment except that no occlusion of the ALA gel was performed. 3 and 6 months after PDT, the clearance rate of a predetermined target lesion and the total clearance rate of all AK within the treated areas were determined. PDT‐induced pain and skin phototoxicity and cosmetic outcome were also recorded.

Results

Clearance rate of the target AK and total AK clearance rate at 3 months after PDT was 88.4% and 90.6% for occlusive PDT and 58.1% (P = .001) and 70.4% (P = .04) for non‐occlusive PDT. The corresponding values at 6 months after PDT were 69.7% and 72.1% for occlusive PDT and 30.2% (P < .001) and 35.6% (P = .001) for non‐occlusive PDT. Pain score and skin phototoxicity were significantly higher after occlusive ALA application. No difference was observed with respect to cosmetic outcome.

Conclusions

Occlusive application of ALA significantly improves the efficacy of PDT but is associated with more pain and increased phototoxicity.
Moral demands and the far future*
Authors: Mogensen Andreas L.
Published: September 2020

I argue that moral philosophers have either misunderstood the problem of moral demandingness or at least failed to recognize important dimensions of the problem that undermine many standard assumptions. It has been assumed that utilitarianism concretely directs us to maximize welfare within a generation by transferring resources to people currently living in extreme poverty. In fact, utilitarianism seems to imply that obligations to help people who are currently badly off are trumped by obligations to undertake actions targeted at improving the value of the long‐term future. Reflecting on the demands of beneficence in respect of the value of the far future forces us to view key aspects of the problem of moral demandingness in a different light.
How to make fire: Resonant rupture within Melanesian charismatic revivalism
Authors: Macdonald Fraser
Published: September 2020

Recent theoretical developments within the anthropology of Christianity have shifted away from conceptualising the uptake of Pentecostal‐charismatic Christianity in polarised terms of rupture versus continuity towards more inclusive, dynamic interpretations that appreciate both underlying cultural synergies alongside deeply felt projects of personal and collective moral and spiritual transformation. Drawing upon Marshall's concept of ‘resonant rupture’, I explore how a series of interconnected revivals that occurred in many places throughout Solomon Islands and Papua New Guinea resonated with pre‐existing elements of indigenous religion and cosmology. At the same time, however, I show that, although a broad conjuncture between tradition and Pentecostal‐charismatic Christianity existed, the events that constituted these movements were understood by revival participants as unequivocally Christian, innovative and radically new, thus revealing the simultaneous processes of resonance and rupture at work. In support of my argument I focus upon reports of religious intensification during this formative period from three different ethnographic settings, namely, Malaita, Solomon Islands, Enga Province, Papua New Guinea and the Min culture area, Papua New Guinea, respectively. All of the examples vividly exemplify Melanesian Christians absorbing existing religiosity into their new worship while at the same time imposing a radical change on the level of asserted meaning.
Do migration networks worsen trade deficit? Evidence from the United States and Germany
Authors: Tomohara Akinori
Published: September 2020

This study investigates how cross‐border movements of goods (trade), people (migration) and capital (FDI) interact comprehensively. While previous studies have examined partial interactions of these factors, such as trade–immigration relationships, little work has been done to examine the effects of global networks on trade balance. Using bilateral trade data, our dynamic panel‐data analysis provides empirical evidence of bidirectional migration networks (i.e. immigration and emigration) and business networks (i.e. inward and outward FDI). The analysis shows that the migration network effect is not definitive but varies depending on countries. The trade deficit in the United States (Germany) increases (decreases) with an increase of immigrants in these countries. For both countries, the trade deficit decreases with emigrants moving abroad. The results imply that the acceptance of immigrants is not a universal cause of trade deficit. Considering that the origin of immigrants differs between the two countries, their respective trade balance is subject to the influence of not only the number of immigrants but also the immigrants' skill level.
Evaluation of the rectal‐interdigital temperature gradient as a diagnostic marker of shock in dogs
Authors: Schaefer Jonathan D. , Reminga Christin L. , Reineke Erica L. , Drobatz Kenneth J.
Published: September 2020

Objective

To evaluate the difference in the rectal‐interdigital temperature gradient (RITG) between dogs that were presented to an emergency room with clinical signs of shock compared to those without signs of shock, and if this gradient can be used as a diagnostic marker for shock.

Design

Prospective, single center, observational study conducted from 2014 to 2015.

Setting

University veterinary teaching hospital.

Animals

Twenty dogs with a clinical diagnosis of shock and 60 dogs without a clinical diagnosis of shock (controls).

Measurements and main results

Upon presentation to the emergency room and prior to intervention, measurements of rectal temperature, interdigital temperature, ambient temperature, systemic markers of perfusion (capillary refill time [CRT], heart rate [HR], respiratory rate [RR], Doppler blood pressure [DBP], and venous plasma lactate concentration), and venous blood gas analytes were recorded. Dogs were initially determined to be in shock by the attending clinician, and post hoc inclusion criteria were applied. Shock was defined as abnormalities in ≥3 of the 6 following criteria: HR > 120/min, RR > 40/min, CRT > 2 seconds, rectal temperature <37.8°C (100.0°F), venous plasma lactate concentration >2.5 mmol/L, or DBP < 90 mm Hg. Animals with circulatory shock had a significantly increased RITG. An increased RITG was also correlated with individual perfusion parameters including prolonged CRT (ρ = .353, P = 0.0013), tachycardia (ρ = .3485, P = 0.0015), decreased DBP (ρ = –0.6162, P = 0.0003), and shock index (ρ = 0.6168, P = 0.0003). Receiver operator curve analysis indicated a RITG cutoff point of 11.6°F had 90% specificity for the diagnosis of shock (area under the curve = 0.7604).

Conclusions

The RITG in this study was associated with a diagnosis of shock and therefore may serve as a diagnostic marker of circulatory shock. Future studies with larger sample sizes to validate the use of temperature gradients and other peripheral perfusion abnormalities as diagnostic and monitoring tools are warranted.
Investigation of Supercritical Flow and Shape of Flip Bucket Spillways on Coefficients of Dynamic Pressure
Authors: Vatandoust Hessam , Yarmohammadi Hamidreza , Kavianpour Mohammadreza
Published: September 2020

Pressure fluctuation is one of the major turbulent flow characteristics. It may cause crucial problems for hydraulic structures. This research is based on experimental studies, and it focuses on the measurements of pressure fluctuations along flip bucket spillways with different geometrical characteristics. The function of the flip bucket spillway is discharging floods from reservoir dams which are energy storage source measurements of dynamic pressures on three different models of flip buckets that were performed for this investigation. Pressure fluctuation of the flip buckets have been measured within a range of Froude numbers from 5 to 13 (Fr = u/gy, where u is the flow speed, y is the depth, and g is 9.81 m/s2). Statistical characteristics of pressure fluctuations, the location, and the values of maximum and minimum fluctuations have also supplemented the study. The results show that the coefficients of pressure fluctuations (Cp = RMS/(0.5(u2/g)) where RMS is the root-mean-square of pressure fluctuation, u is the flow speed, and g is 9.81 m/s2) reduce as the Froude number (Fr) of flow increases, except a maximum Froude number. Pressure coefficients increase along the flip bucket with incremental mutations in the transformation area of the flip bucket. In the middle part of the flip bucket spillway, pressure coefficient values decrease. Additionally, as B/r (B is the width of the flip bucket and r is the radius of the flip bucket) ratio increases, pressure coefficients become larger and this process continues along the flip bucket.
Assimilation of Experimental Data to Create a Quantitatively Accurate Reduced-Order Thermoacoustic Model
Authors: Garita Francesco , Yu Hans , Juniper Matthew P.
Published: September 2020

We combine a thermoacoustic experiment with a thermoacoustic reduced order model using Bayesian inference to accurately learn the parameters of the model, rendering it predictive. The experiment is a vertical Rijke tube containing an electric heater. The heater drives a base flow via natural convection, and thermoacoustic oscillations via velocity-driven heat release fluctuations. The decay rates and frequencies of these oscillations are measured every few seconds by acoustically forcing the system via a loudspeaker placed at the bottom of the tube. More than 320,000 temperature measurements are used to compute state and parameters of the base flow model using the Ensemble Kalman Filter. A wave-based network model is then used to describe the acoustics inside the tube. We balance momentum and energy at the boundary between two adjacent elements, and model the viscous and thermal dissipation mechanisms in the boundary layer and at the heater and thermocouple locations. Finally, we tune the parameters of two different thermoacoustic models on an experimental dataset that comprises more than 40,000 experiments. This study shows that, with thorough Bayesian inference, a qualitative model can become quantitatively accurate, without overfitting, as long as it contains the most influential physical phenomena.
Laboratory Assessment of a Headband-Mounted Sensor for Measurement of Head Impact Rotational Kinematics
Authors: Huber Colin M. , Patton Declan A. , Wofford Kathryn L. , Margulies Susan S. , Cullen D. Kacy , Arbogast Kristy B.
Published: September 2020

Head impact sensors measure head kinematics in sports, and sensor accuracy is crucial for investigating the potential link between repetitive head loading and clinical outcomes. Many validation studies mount sensors to human head surrogates and compare kinematic measures during loading from a linear impactor. These studies are often unable to distinguish intrinsic instrumentation limitations from variability caused by sensor coupling. The aim of the current study was to evaluate intrinsic sensor error in angular velocity in the absence of coupling error for a common head impact sensor. Two Triax SIM-G sensors were rigidly attached to a preclinical rotational injury device and subjected to rotational events to assess sensor reproducibility and accuracy. Peak angular velocities between the SIM-G sensors paired for each test were correlated (R2 > 0.99, y = 1.00x, p < 0.001). SIM-G peak angular velocity correlated with the reference (R2 = 0.96, y = 0.82x, p < 0.001); however, SIM-G underestimated the magnitude by 15.0% ± 1.7% (p < 0.001). SIM-G angular velocity rise time (5% to 100% of peak) correlated with the reference (R2 = 0.97, y = 1.06x, p < 0.001) but exhibited a slower fall time (100% to 5% of peak) by 9.0 ± 3.7 ms (p < 0.001). Assessing sensor performance when rigidly coupled is a crucial first step to interpret on-field SIM-G rotational kinematic data. Further testing in increasing biofidelic conditions is needed to fully characterize error from other sources, such as coupling.
A Comparative Study Between Two-Dimensional and Three-Dimensional Simulation Results of Melting Inside a Container
Authors: Hu Nan , Fan Li-Wu
Published: September 2020

Bother two-dimensional (2D) and three-dimensional (3D) simulations on two example melting problems, i.e., melting in a differentially-heated rectangular cavity and constrained melting in a horizontal cylindrical capsule, were carried out to investigate the rationality of 2D simplification. The effects of thermophysical properties of the phase change material, size of the container along the direction perpendicular to the 2D cross-section, as well as wall superheat were taken into consideration for a systematic and detailed comparison. It was shown that a small length of the container perpendicular to 2D plane will result in a confine space to limit the development of velocity distribution (i.e., parabolic velocity profile) due to the end effects, leading to to an almost identical melting rate to that obtained by the 2D simplified case. A larger size indicates stronger thermal convection (bulk uniform velocity profile) and faster melting rate. When fixing a large size of the container perpendicular to the 2D plane, decreasing the heating temperature and increasing the viscosity of liquid PCM (e.g., by adding nanoparticles) reduce the discrepancy between 2D and 3D simulation results.
Comparative Study of Heat Transfer in a Mini/Micro Pipe With Water and Liquid Metal As Fluid
Authors: Zhang Xu-Dong , Gao Jian-Ye , Liu Jing
Published: September 2020

Recently, the new research field of room temperature liquid metal cooling for extreme heat flux electronic devices has gradually attracted much attention. And many investigations claimed that liquid metal cooling has a better heat transfer performance than water cooling. However, such a conclusion was just applicable to the special geometry sizes. This paper is dedicated to deeply interpret and systematically compare the laminar heat transfer in a mini/micro pipe with water and liquid metal as heat transfer fluid. Theoretical analysis for the laminar fully developed segment and numerical investigation for the laminar developing segment were conducted. The results indicated that liquid metal galinstan shows a better heat transfer performance in mini-pipe. And the shorter the pipe, the better performance the liquid metal cooling has. However, when the velocity is small, the galinstan cooling is worse than water cooling in micro-pipe. Moreover, based on thermal resistance analysis, the general criterion equation for laminar developed segment was derived to judge which cooling method possesses a better heat transfer performance. Overall, this comparative study provides a comparison method and criterion about liquid metal cooling and water cooling, which will attribute to the coolant selection and heat sink design.
Thermal Performance of Sensible Energy Storage Module Consisting of a Cementitious Matrix: The Effect of Operating Conditions
Authors: Caspar Justin , Bravo Julio , Wang Shuoyu , Abdulridha Ahmed , Neti Sudhakar , Romero Carlos , Naito Clay , Sulieman Muhannad , Quiel Spencer , Yao Zheng , Oztekin Alparslan
Published: September 2020

The fluid flow and heat transfer inside a concrete thermal energy storage module is simulated for various heat transfer fluid flow rates and inlet temperatures. The storage performance of the module is characterized based on the volume-averaged temperature and normalized energy distribution through the block versus time. In the turbulent flow regime, induced mixing in the pipe strongly enhanced the performance of the module compared to the laminar regime. The block was able to fully charge and discharge in a turbulent flow regime, whereas that behavior was not present in the laminar flow regime.

Varying the heat transfer temperature had an effect on the time rate of change of temperature as well as the charge times. As the thermal gradient increased, the initial time rate of temperature in the block increased as well as the charge time. Since the block has higher theoretical energy at a larger gradient, power over a longer duration is necessary to reach a saturation point. By characterizing the thermal performance of the module, the effect of material properties and operational parameters can be studied in order to design a module that can meet the needs of a power generation plant.
Condensation and Evaporation Heat Transfer Characteristics in Horizontal Smooth and Three-Dimensional Enhanced Tubes
Authors: Zhang Jianghui , Guo Yu , Zhang Chuancai , He Yan , Kukulka David J. , Li Wei
Published: September 2020

An experimental investigation of condensation and evaporation heat transfer characteristics was performed in a smooth tube and two enhanced tubes (1EHT, 3EHT) using R134A as refrigerant. All tested tubes have the same inner diameter of 14.68mm and outer diameter of 15.88mm. The enhanced surface of the 1EHT tube is made up by dimples and a series of petal arrays, while that of 3EHT tube is rectangular cavities. The test runs are performed at a saturation temperature of 45°C, over the quality range of 0.8–0.2 for condensation and at a saturation temperature of 6°C, over the quality range of 0.1–0.6 for evaporation. For evaporation, the heat transfer coefficient ratio (hEHT/hs) is approximately 1.2–1.4 for mass from 50–90 kg/m2s. For condensation, the 1EHT tube provides the best condensation heat transfer performance. This is mainly due to the dimples and rectangular cavities that increase heat transfer surface area and interface turbulence, producing additional disturbances, secondary flows near the boundary and flow separation.
A Multiobjective Parameter Study of Two-Phase Flow Channel Design
Authors: Evich Nicholas A. , Larimer Nicholas R. , Frecker Mary I. , Rau Matthew J.
Published: September 2020

Advanced manufacturing techniques have improved dramatically in recent years and design freedom for engineered components and systems has never been greater. Despite these advancements, the majority of our design tools for thermal-fluids systems are still rooted within traditional architectures and manufacturing techniques. In particular, the complex nature of two-phase flow and heat transfer has made the development of design methods that can accommodate these complex geometries enabled by new manufacturing techniques challenging. Here, we investigate a new design method for two-phase flow systems. We conduct a multiobjective parameter study considering two-phase flow and heat transfer through a single channel with a circular cross section. To increase our design degrees of freedom, we allow the channel to increase or decrease in cross-sectional area along its flow length, but constrain the channel inlet and outlet to a constant hydraulic diameter. Maximizing heat transfer and minimizing pressure drop are the two design objectives, which we evaluate using two-phase heat transfer correlations and the Homogeneous Equilibrium Model. We find that using small expansion angles can greatly reduce two-phase flow pressure drop and also provide high heat transfer coefficients when compared to straight channel designs. We present a set of feasible designs for varying input heat fluxes, liquid mass flow rates, and channel orientation angles and show how the ideal expansion channel angle varies with these operational conditions.
Application of Artificial Neural Network As a Near-Real Time Technique for Solving Non-Linear Inverse Heat Conduction Problems in a One-Dimensional Medium With Moving Boundary
Authors: Najafi Hamidreza , Uyanna Obinna , Zhang Jian
Published: September 2020

Developing accurate and stable solutions for inverse heat conduction problems (IHCPs) is crucial in many industrial applications where direct measurement of surface conditions, such as heat flux or temperature, is not possible in practice and temperature measurement from interior points can be obtained alternatively. IHCPs are mathematically ill-posed and therefore developing stable solutions for them is challenging. Application of intelligent algorithms for solving IHCPs has been successfully explored for several cases. In the present paper, the problem of near real-time surface heat flux estimation in a one-dimensional domain with temperature dependent material properties and moving boundary is considered. An artificial neural network (ANN) is developed to use the temperature measurement data from interior points for limited number of time steps as the inputs and calculate the surface heat flux and recession rate at the current time step as the output of the network. For this purpose, a multi-layer perceptron (MLP) network is selected, trained and tested using heat flux-temperature data that were evaluated via COMSOL Multiphysics for a 1D medium that is exposed to standard heat flux profiles on its surface (including triangular, parabolic and step function). A randomly generated heat flux profile is also applied to the surface of the medium and temperature distribution is calculated via COMSOL Multiphysics. The temperature data are then used as the inputs to the network and surface heat flux is evaluated under this condition to assess the capability of the developed ANN in surface heat flux estimation. The performance of the network when using different number of inputs (previous and future time steps from which temperature data are needed for surface heat flux estimation) as well as different network topology are explored in the presence of random measurement error. The results show that the developed approach allows accurate near real-time surface heat flux estimation in a 1-D medium with temperature dependent material properties and moving boundary. The solution of this problem can be further extended to be used in sensors for ablative thermal protection system in space vehicles.
Use of Genetic Algorithms and Machine Learning to Explore Parametric Trends in Nucleate Boiling Heat Transfer Data
Authors: McClure Emma R. , Carey Van P.
Published: September 2020

Exploring parametric effects in pool boiling is particularly challenging because the dependence of the resulting surface heat flux on many parameters is non-linear, and the mechanisms can interact in complex ways. Historically, parametric effects in nucleate boiling processes have most often been deduced by fitting relations obtained from physical models to experimental data, or looking for correlated trends in non-dimensionalized data. Using such approaches, observed trends are often influenced by the framing of the analysis that results from the modeling or the collection of dimensionless variables used. Machine learning strategies can be attractive alternatives because they can be constructed either to minimize biases or to emphasize specific biases that reflect knowledge of the physics of the system. The investigation summarized here explored the use of machine learning methods as a tool for determining parametric trends in boiling heat transfer data, and as a means for developing methods to predict boiling heat transfer. Results are presented that demonstrate how genetic algorithms and other machine learning tools can be used to extract heat flux dependencies on system parameters. A key element of the machine learning analysis process is preparation of the data used. Use of raw data and use of dimensionless rescaled data are explored, and the advantages and disadvantages of each are assessed. Data for nucleate boiling of a binary mixture are analyzed to determine the heat flux dependence on wall superheat, gravity, Marangoni effects and pressure. The results provide new insight into how gravity and Marangoni effects interact in boiling processes of this type. The results also demonstrate how machine learning tools can clarify how different mechanisms interact in the boiling process, as well as directly providing the ability to predict heat transfer performance for design of heat transfer devices that involve nucleate boiling. Potential use of machine learning tools on big data collections for nucleate boiling processes to more broadly assess parametric effects is also discussed.
Design and Optimization of Microchannel Heat Sink for Densely Packed High Concentration Solar Cells
Authors: M. Ali Abdallah Y. , Abo-Zahhad Essam M. , Radwan Ali , Elqady Hesham I. , El-Kady M. F. , Ookawara Shinichi , El-Shazly A. H.
Published: September 2020

High cell operation temperature causes a significant reduction in cell efficiency. Besides, this high temperature reduces the cell lifespan and physical damages could happen due to thermal stresses. An advanced and efficient cooling scheme is obligatory to operate a high concentration solar module under its recommended operating conditions. The main objective of this work is to design and optimize a microchannel heat sink in terms of channel geometry for high concentration photovoltaic module works under high solar concentration for more efficient and uniform cooling. A complete three-dimensional model for the high concentrator photovoltaic module coupled with the microchannel heat sink is developed. A densely packed high concentration solar module consists of AZURSPACE product triple-junction solar cells (electrical efficiency is 43.2% at a cell temperature of 25 °C) is considered as a heat source in this work. The multi-objective optimization method is adopted to obtain the optimum channel dimensions. Both channel width and height are defined as variable parameters. The optimum design is obtained then its thermal performance is investigated under different working conditions. The results confirmed the ability of the optimized cooling device to offer efficient thermal management and uniform cooling for a densely packed high concentration solar module.
Numerical Investigation of Thermal Properties for Li-Ion Battery
Authors: Wang Xiuling
Published: September 2020

Li-ion battery is becoming a popular energy storage device in Hybrid Electric Vehicles (HEV) and Electric Vehicles (EV) due to its high energy density, high voltage and low self-discharge rate. The major concerns in designing Li-ion batteries are their life, performance and safety, which have close relations to their thermal behaviors. The temperature of Li-ion batteries rises during charge/discharge process. It goes faster especially with high charge/discharge rate during fast charging procedure. In this research, CFD models are developed based on ANSYS/FLUENT MSMD battery model coupled with electrochemical submodel-Newman, Tiedeman, Gu and Kim (NTGK) empirical model. Detailed simulation results are obtained in battery thermal and electrochemical behavior for different bi-cell electrode and current collector tab configurations. The temperature, potential, current density distribution at the battery length scale are determined, temperature gradient distribution is computed, and the maximum temperature at different discharge rate are also compared. The thermal investigation can provide valuable input for Li-ion battery design and analysis, especially for fast-charging batteries where heat distribution and cooling is critical for the battery design.
Numerical Simulation of Heat, Air, and Moisture Transfer Through a Wall of Porous Media
Authors: Tesfamariam Kiflom B. , Lin Cheng-Xian (Charlie) , Liu Fang
Published: September 2020

This paper presents the results of two-dimensional (2D) numerical simulation of heat, air, and moisture transfer through porous walls, which have important application background in the built environment and other engineering fields. The air flows, heat and moisture transfer in the walls are studied using a transient heat, air, and moisture (HAM) model. This model treats the non-isothermal airflow through two-dimensional porous geometries in a time-dependent format. The model includes the Brinkman equation describes the flow of air and other mathematical equations that calculate the heat and moisture transfer through the porous region. The equations are solved by a finite element method (FEM) using physics-based modeling, which is implemented in the commercial simulation software, COMSOL Multiphysics. The model prediction is first validated by using published benchmark solutions. Eventually, the numerical results are presented to illustrate the complex effects of material porosity and permeability on the heat and moisture transport, and moisture content variation in space and time through the walls, at different humidity and temperature conditions. Within the investigated parameter ranges, it is demonstrated that the relative humidity and temperature difference are the driving forces for the transient heat, air, and moisture transport processes through the porous area in the porous walls.
Numerical Investigation on a Compact Heat Exchanger Partially Filled With Metal Foam
Authors: Buonomo Bernardo , di Pasqua Anna , Manca Oronzio , Nappo Sergio , Umavathi Jawali C.
Published: September 2020

In this paper a numerical investigation has been accomplished to study the thermal and fluid dynamic behavior of a tubular heat exchanger partially filled with metal foam. The Darcy – Brinkman - Forchheimer model and the local thermal non-equilibrium hypothesis (LTNE) for the thermal energy are used to execute two-dimensional analyses on the aluminum foam heat exchanger. The heat exchanger is studied for several air flow rates and a fixed temperature on the surface tube. The results are shown in terms of heat transfer rate and pumping power. Furthermore, the ratios in terms of heat transfer rate and pumping power are given for the two different configurations (partially and totally filled) in order to find the most convenient scheme. Furthermore, the temperature and pressure fields are evaluated. a comparison among the different thickness of the metal foam between two adjacent tubes and the fully filled configuration is given. The results show that the smaller value of metal foam thickness is characterized by a better performance.
The Effects of Occupancy and Solar Energy on Homes in the Pacific Northwest Constructed According to Improved Thermal Standards
Authors: Heerwagen D. R. , Nicoliasen K. , Emery A. F.
Published: September 2020

The space heating energy needed during the winter heating season in Seattle Washington, USA, was monitored over a 15 year period, 1987–2002. Single family residence houses were constructed to building code standards in force at the time of construction and two more to standards calling for envelopes with improved thermal resistance. Although space conditioning energy needs are strongly affected by occupant behavior, simulations generally ignore the temporal occupant behavior in estimating the energy needed for heating and cooling. Vigorous conservation tactics, which produce a thermal response that is highly transient, can lead to substantially different energy needs. No correlation could be established from the measured space heating when aggressive conservation made use of thermostat setback at every opportunity. In this paper we investigate the effects of occupant behavior and the effect of temporal solar heating of walls in the Seattle area for improved thermal construction.
3D Shape Prediction of a Paper Model for a Brassiere Cup Consisting of Multiple Polygonal Patterns
Authors: Wakamatsu Hidefumi , Shirai Kyosuke , Morinaga Eiji , Kubo Takahiro
Published: September 2020

A general method is proposed to predict the shape of a paper model of a brassiere cup. A brassiere cup consists of several cloth and wire parts and the shapes of cloth parts are determined by repeating creation of a paper cup model, check of its 3D shape, and modification of 2D shapes of parts. For efficient design of a brassiere cup, prediction of its 3D shape with a simulation is required. The deformed shape of a paper part is represented as a single or multiple developable surfaces. So, a model that can represent a part both as a single surface and as multiple surfaces is proposed. Which case is selected depends on the magnitude of the potential energy of the part in each case. The potential energy of the part and geometric constraints imposed on the part are formulated based on the model. Minimizing the potential energy under geometric constraints derives the stable shape of the part in either case. Furthermore, our proposed method can be applied to prediction of the paper cup model consisting of parts with complex shapes.