bluuebunny/crossref_metadata_2025 huggingface dataset:
Shifting urban mobility patterns due to COVID-19: comparative analysis of implemented urban policies and travel behaviour changes with an assessment of overall GHG emissions implications
Authors: Creutzig Felix , Lohrey Steffen , Franza Mercedes Vázquez
Published: September 2022

COVID-19-induced confinements rapidly change behavioural patterns and social norms of street space use worldwide. In the following study we compile data to assess shifting urban mobility during confinement (phase 1), and in reaction to COVID-19 induced physical distancing policies (phase 2). In a comparative analysis of 16 cities, we show that public transit decreased by 80% during confinement, but individual motorized transport only by 64%. Cycling modal share increased in some cities. COVID-19 and sustainability are intertwined via risks, susceptibility, and positive and negative outcomes, in particular via sustainable development goal 3 (SDG3) (health), SDG5 (gender equality), SDG11 (sustainable cities) and SDG13 (climate action). Confinement-induced social gains are realized in reduced congestion, improved air quality, and less accidents, partially compensated by unhealthy eating, and domestic violence. Our analysis reveals that cities around the world provided more space for cyclist and pedestrians as part of pandemic-related measures, pedestrianizing streets, implementing 550 km ad-hoc bicycle infrastructure and planning additional 1500 km. Our computation indicates that GHG emissions savings due to increased uptake of cycling in the EU reduced urban land transport GHG emissions by 0.3% (1 Mt CO2), while GHG emission savings were larger in cities with pop-up bicycle lanes (between 0.43% and 1.87%). Our findings also demonstrate that proactive cities had already plans in their drawers and demonstrated institutional alignment of vocal civil society, administrations and politicians. We argue that long-term sustainability trajectories of cities will depend on transformation of both physical and digital infrastructures.
Increased glutamatergic synaptic transmission during development in layer II/III mouse motor cortex pyramidal neurons
Authors: Burnsed Jennifer , Matysik Weronika , Yang Lu , Sun Huayu , Joshi Suchitra , Kapur Jaideep
Published: September 2022

Postnatal maturation of the motor cortex is vital to developing a variety of functions, including the capacity for motor learning. The first postnatal weeks involve many neuronal and synaptic changes, which differ by region and layer, likely due to different functions and needs during development. Motor cortex layer II/III is critical to receiving and integrating inputs from somatosensory cortex and generating attentional signals that are important in motor learning and planning. Here, we examined the neuronal and synaptic changes occurring in layer II/III pyramidal neurons of the mouse motor cortex from the neonatal (postnatal day 10) to young adult (postnatal day 30) period, using a combination of electrophysiology and biochemical measures of glutamatergic receptor subunits. There are several changes between p10 and p30 in these neurons, including increased dendritic branching, neuronal excitability, glutamatergic synapse number and synaptic transmission. These changes are critical to ongoing plasticity and capacity for motor learning during development. Understanding these changes will help inform future studies examining the impact of early-life injury and experiences on motor learning and development capacity.
Top-down modulation and cortical-AMG/HPC interaction in familiar face processing
Authors: Fan Xiaoxu , Guo Qiang , Zhang Xinxin , Fei Lingxia , He Sheng , Weng Xuchu
Published: September 2022

Humans can accurately recognize familiar faces in only a few hundred milliseconds, but the underlying neural mechanism remains unclear. Here, we recorded intracranial electrophysiological signals from ventral temporal cortex (VTC), superior/middle temporal cortex (STC/MTC), medial parietal cortex (MPC), and amygdala/hippocampus (AMG/HPC) in 20 epilepsy patients while they viewed faces of famous people and strangers as well as common objects. In posterior VTC and MPC, familiarity-sensitive responses emerged significantly later than initial face-selective responses, suggesting that familiarity enhances face representations after they are first being extracted. Moreover, viewing famous faces increased the coupling between cortical areas and AMG/HPC in multiple frequency bands. These findings advance our understanding of the neural basis of familiar face perception by identifying the top-down modulation in local face-selective response and interactions between cortical face areas and AMG/HPC.
Increased Efficiency of Mitochondrial Coupling With a Reduction in Other Mitochondrial Respiratory Parameters in Peripheral Blood Mononuclear Cells Is Observed in Older Adults
Authors: Sriwichaiin Sirawit , Apaijai Nattayaporn , Phrommintikul Arintaya , Jaiwongkam Thidarat , Kerdphoo Sasiwan , Pratchayasakul Wasana , Thongmung Nisakron , Mahantassanapong Usanee , Vathesatogkit Prin , Kitiyakara Chagriya , Sritara Piyamitr , Chattipakorn Nipon , Chattipakorn Siriporn C
Published: September 2022

Mitochondrial dysfunction is a factor potentially contributing to the Aging process. However, evidence surrounding changes in mitochondrial function and aging is still limited; therefore, this study aimed to investigate further the association between them. Possible confounding factors were included in the statistical analysis to explore the possibility of any independent associations. One thousand seven hundred and sixty-nine participants (619 middle-aged adults [age < 65] and 1,150 older adults [age ≥ 65]) from the Electricity Generating Authority of Thailand were enrolled in the study. The clinical characteristics and medical history were collected. Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood and used for analysis of mitochondrial function. Several parameters pertinent to mitochondrial respiration including non-mitochondrial respiration, basal respiration, maximal respiration, proton leak, and spare respiratory capacity were found to be two to three times lower in the mitochondria isolated from the cells of older adults. Interestingly, the mitochondrial ATP production was only slightly reduced, and the percentage of coupling efficiency of PBMC mitochondria was significantly higher in the older adult group. The mitochondrial mass and oxidative stress were significantly reduced in older adult participants; however, the ratio of oxidative stress to mass was significantly increased. The association of these parameters with age was still shown to be the same from the outcome of the multivariate analyses. The mitochondrial functions and mitochondrial mass in PBMCs were shown to decline in association with age. However, the upregulation of mitochondrial oxidative stress production and mitochondrial coupling efficiency might indicate a compensatory response in mitochondria during aging.
A two-stage deep neural model with capsule network for personality identification
Authors: Naseri Zahra , Momtazi Saeedeh
Published: September 2022

People have different ways of thinking, feeling, and hence acting, which resulted in different personalities. Understanding one’s personality and how it can be automatically identified considering the way he/she communicates to the world around can be challenging; but it can also be useful in many cases. Deep learning algorithms perform fairly well in text-based personality detection. However, many computational personality assessment models rely on limited domain knowledge. There are different personality models for classifying personality traits according to the definitions of psychologists. In this paper, we focus on the Myers–Briggs Type Indicator (MBTI) model and explain how a two-stage deep neural model for personality identification can use more information from text and therefore, have better performance in classifying input data. To this end, in the first stage, we use capsule neural networks to extract meaningful hidden patterns from word-level semantic representation to be used for calculating personality traits. Moreover, in the second stage of the proposed architecture, we benefit from contextualized document-level representation of text as well as statistical psychological features. Our experimental results on the Myers–Briggs Personality Type dataset from Kaggle which has been labeled based on the MBTI model show improvement in personality identification compared to the state-of-the-art models in the field.
An openness framework for ex ante evaluation of societal impact of research
Authors: Benneworth Paul , Olmos-Peñuela Julia
Published: September 2022

Over the last decade, the idea of societal impact resulting from publicly funded research has changed from being a relatively fringe concern related to high-technology entrepreneurship and spin-off companies to becoming an increasingly important public policy concern. This has stimulated academic science policy research to investigate the impact of research and conceptualize how knowledge created in academic contexts can be coupled to real-world problems or needs. Most of the work in this stream of research focuses on ex post impacts, that is, the impacts created by individual research activities or research strands after their completion and likewise there has been much research on ex post impact evaluation. However, ex ante impact evaluations have become increasingly important for funding decisions, but little is known about how to evaluate impact when considering research project proposals. In this article, we propose a conceptual framework to evaluate ex ante impact of research based on the idea that a research proposal is a ‘promise’ to achieve impact. We suggest that evaluators could assess social impact promises by considering two elements, namely the activities that couple their knowledge with non-academic users and the interdependency and consistency of such activities throughout the overall project proposal. We ultimately propose an analytical framework for refining our ‘openness’ conceptual framework in future empirical research.
A Multicenter, Randomized, Double-Blinded, Clinical Trial Comparing Cattell-Warren and Blumgart Anastomoses Following Partial Pancreatoduodenectomy
Authors: Halloran Christopher M. , Neoptolemos John P. , Jackson Richard , Platt Kellie , Psarelli Eftychia-Eirini , Reddy Srikanth , Gomez Dhanwant , O’Reilly Derek A. , Smith Andrew , Pausch Thomas M. , Prachalias Andreas , Davidson Brian , Ghaneh Paula
Published: September 2022

Objective:

Whether a Blumgart anastomosis (BA) is superior to Cattell-Warren anastomosis (CWA) in terms of postoperative pancreatic fistula (POPF) following pancreatoduodenectomy.

Importance:

Complications driven by POPF following pancreatic cancer resection may hinder adjuvant therapy, shortening survival. BA may reduce complications compared to CWA, improving the use of adjuvant therapy and prolonging survival.

Methods:

A multicenter double-blind, controlled trial of patients undergoing resection for suspected pancreatic head cancer, randomized during surgery to a BA or CWA, stratified by pancreatic consistency and duct diameter. The primary end point was POPF, and secondary outcome measures were adjuvant therapy use, specified surgical complications, quality of life, and survival from the date of randomization. For a 10% POPF reduction, 416 patients were required, 208 per arm (two-sided α = 0·05; power = 80%).

Results:

Z-score at planned interim analysis was 0.474 so recruitment was held to 238 patients; 236 patients were analyzed (112 BA and 124 CWA). No significant differences in POPF were observed between BA and CWA, odds ratio (95% confidence interval [CI]) 1·04 (0.58–1.88), P = 0.887, nor in serious adverse events. Adjuvant therapy was delivered to 98 (62%) of 159 eligible patients with any malignancy; statistically unrelated to arm or postoperative complications. Twelve-month overall survival, hazard ratio (95% CI), did not differ between anastomoses; BA 0.787 (0.713–0.868) and CWA 0.854 (0.792–0.921), P = 0.266, nor for the 58 patients with complications, median (IQR), 0.83 (0.74–0.91) compared to 101 patients without complications 0.82 (0.76–0.89) (P = 0.977).

Conclusions:

PANasta represents the most robust analysis of BA versus CWA to date.
Perception of higher frequency of daily hot flashes in 50-year-old women today: a study of trends over time during 48 years in the Population Study of Women in Gothenburg, Sweden
Authors: Rödström Kerstin , Weman Lilian , Sundh Valter , Björkelund Cecilia
Published: September 2022

Objective

The aim of this study was to examine if there are any differences in the prevalence of daily hot flashes in 50-year-old women in a longitudinal perspective (from 1968 to 2017).

Methods

Cohort comparisons of four population-based samples of 50-year-old women born in 1918, 1930 (earlier-born cohorts), 1954, and 1966 (later-born cohorts) from the Prospective Population Study of Women in Gothenburg examined in 1968-1969, 1980-1981, 2004-2005, and 2016-2017. Questions about frequency of hot flashes have been formulated in the same way throughout all follow-up examinations. Changes between four generations of 50-year-old women were studied.

Results

In the unadjusted model, we found an increased prevalence of daily hot flashes in 50-year-old women born in 1954 and 1966 compared with 50-year-old women born in 1918 and 1930 (odds ratio, 1.74; 95% confidence interval, 1.37-2.22). When considering potential predictors for daily hot flashes (smoking, perceived level of high stress, BMI, waist-to-hip ratio, hormone therapy, and hormonal contraceptives) in the adjusted model, there was a notable difference; odds ratio increases from 1.74 to 1.92 (95% confidence interval, 1.46-2.52). Smoking frequency was substantially lower in the later-born cohorts, 39% compared with 17%.

Conclusions

In this prospective longitudinal study of 50-year-old women, we found nearly twice as high odds of reporting daily hot flashes in the later-born women compared with earlier-born. When controlling for potential predictors, there was still an obvious difference, which cannot be explained in our study. These findings have not earlier been described, and there is a need for further longitudinal population studies investigating the prevalence of hot flashes over time. Moreover, additional research is required exploring the underlying mechanism of hot flashes, as well as studies that take into account potential risk factors in the environment and societal development over time, that is, impacts of endocrine-disrupting chemicals changes in lifestyle, environmental, and dietary factors, as well as working conditions.
Disseminated Gonococcal Infections (DGI) in Manitoba, Canada: 2013 to 2020
Authors: Sawatzky Pam , Martin Irene , Thorington Robyn , Alexander David
Published: September 2022

Background

Gonorrhea, when left untreated, can enter the blood and cause disseminated gonococcal infections (DGI). DGI, which can include dermatitis, tenosynovitis, migratory polyarthralgia and arthritis, have been increasing in Manitoba (MB), Canada since 2013. Endocarditis, a rare DGI was identified in three MB patients in 2018 and 2019.

Methods

Antimicrobial resistance, molecular types and resistance-associated mutations were determined for MB DGI isolates (n = 103) identified from 2013-2020 using phenotypic and genotypic methods. Neisseria gonorrhoeae Multi-Antigen Sequence Typing (NG-MAST) of residual nucleic acid amplification testing (NAAT) samples (n = 13) from 2019 and 2020 were also determined.

Results

The increase in DGI in MB in 2019 and 2020 was due to the NG-MAST-11508 molecular type with porB-2206, a persistent PorB protein structure type 'A' allele. These isolates had low level resistance to erythromycin and tetracycline.

Conclusions

Molecular surveillance of gonorrhea and in particular, gonococcal strains resulting in DGI is imperative to monitor clonal transmission within populations. This data can be used to alert public health of emerging issues and support public health interventions.
Transforming health science libraries around the globe: The impact of technology
Authors: Murphy Jeannette
Published: September 2022

Health science libraries have been using information technology since the late 1960s, shaping both the profession and the mission of these libraries. To explore the impact of technology, a series of articles has been commissioned for the HILJ Regular Feature, International Perspectives and Initiatives. This editorial sets the scene for this series of articles, which starts in this issue. These articles, written by health science librarians from around the globe, will explore the impact of technology on the way health science libraries provide information in the digital age. Some articles will look at national trends and others will focus on a particular library. A key theme is how technology is being used to support the mission of health science libraries and whether technology has altered that mission. This editorial provides a brief overview of the technologies libraries have adopted, from the 1970s to the present day. From this, it is clear that information technology has transformed the way health information is collected, catalogued, and disseminated to users. And it is certain that in the coming decade new technologies will be incorporated into health science libraries, which will pose challenges for both users and librarians. However, librarians will continue to find ways to adapt and use these tools to meet the needs of their users.
Experimental and Modelling Analysis of a Large-Scale Two-Phase Loop Thermosyphon
Authors: Isaac Aragones Debraliz , Chen Chien-Hua , Weibel Justin A. , Warsinger David M. , Bonner Richard W.
Published: September 2022

Liquid pumping requires large quantities of electrical energy, including about 7% of the energy of building heating, ventilation, and air conditioning (HVAC) systems. To replace pumped condenser-cooling tower water loops with a passive alternative system, we implemented a commercial-scale two-phase loop thermosyphon (TPLT). The unit consists of a 13 m riser integrated with a commercially available cooling tower and circulation water heater that simulates heat loads up to 25 kW. In addition to providing passive cooling capabilities, the cooling tower unit is also maintenance free, reliable, and can operate in both dry and wet modes. This study characterizes the performance (temperature difference between the evaporator and condenser) and the two-phase flow behavior of the loop under various refrigerant charges. Sight glasses installed throughout the loop are used to identify the operating flow regimes in the riser and downcomer. Over the range of operating conditions, we identified that there is an optimal refrigerant charge range for a specific heat load at which near-isothermal operation can be achieved. We further developed a model to predict the operating flow rate and gravitational height in the downcomer and compared it with the experimental data. The results show that the model agrees with the experimental data, in particular the threshold gravitational head height at which there will be subcooled liquid at the condenser exit, indicating that it can be used as a predictive tool for identifying the optimal loop charge for a given heat load.
Characterization of Vented Gas Predictions in Lithium-Ion Modeling With 1-D Thermal Runaway (LIM1TR)
Authors: Qatramez Ala' E. , Kurzawski Andrew , Hewson John , Parker Michael , Porter Adam , Foti Daniel , Headley Alexander J.
Published: September 2022

Thermal runaway and its propagation are major safety issues in containerized lithium-ion battery energy storage systems. While conduction-driven propagation has received much attention, the thermal hazards associated with propagation via hot gases vented from failing cells are still not fully understood. Vented gases can lead to global safety issues in containerized systems, via heat transfer to other parts of the system and potential combustion hazards. In this work, we validate the characteristics of vented gases from cells undergoing thermal runaway in the thermal propagation model LIM1TR (Lithium-ion Modeling with 1-D Thermal Runaway). In particular, we assess the evolution of vented gases, venting time, and temperature profiles of single cell and multi-cell arrays based on experiments performed in Archibald et al (Fire Technology, 2020). While several metrics for estimating the venting time are assessed, a metric based on the CO2 generation results in consistent predictions. Vented gas evolution, and venting times predicted by the simulations are consistent with those estimated during the experiments. The simulation resolution and other model parameters, especially the use of an intra-particle diffusion limiter, have a large role in prediction of venting time.
Experimental Results of Simulation of a Combined Flash Evaporation and Phase Separation System for Desalination of Sea Water
Authors: Chandramouli Vasudevan , Jen Jin , Dhir Vijay
Published: September 2022

With demand for fresh water ever-increasing, it is essential to find ways for producing fresh water. Due to its abundance, sea water near coastal regions is a logical choice for desalination. Developing desalination systems that are scalable, energy efficient, and cost effective becomes imperative. A novel system combining dynamic flash evaporation and vapor separation for desalination in a single step was investigated in this work. Water from a primary tank at atmospheric pressure was pumped to higher pressure and simultaneously heated to temperature close to saturation. Heated water was injected tangentially into a separator tube section through two injection passages and injectors. Dynamic pressure drop due to friction and acceleration occurs when the initially subcooled water passes through the injection passages and injectors resulting in flashing. Flashing produces liquid-vapor two phase mixture which when tangentially injected results in centrifugal separation. A vapor core with liquid annulus forms in the separator tube. Vapor was removed with a retrieval tube placed in the vapor core and was directed to the condenser where condensation at atmospheric pressure take place. Thermal conversion efficiency based on the utilization of available superheat for vapor production and phase separation efficiency dependent on the mass-based quality of condensate were defined to evaluate the system. Thermal conversion efficiencies and phase separation efficiencies of up to 98% were achieved in the experiments. Parametric effects of flowrate, superheat, retrieval tube size on thermal conversion and phase separation efficiencies were studied. Experimental results with sea water as test fluid and purity of condensate achieving 98% by weight were reported.
An Experimental Investigation of Flow Boiling Characteristics in Interconnected Microchannels With Different Slot Arrangement
Authors: Li Yun , Wu Huiying
Published: September 2022

Flow boiling in microchannels is a promising approach to solve the heat dissipation problems of the electronic components. In this work, two types of interconnected slot microchannels (SM) with the staggered (SSM) and in-line (ISM) arrangement of the slots (W = 300μm, H = 600μm) are fabricated. Flow boiling experiments are conducted in the SMs (W = 300μm, H = 600μm, L = 35mm) at mass fluxes of 118–370 kg/m2·s, with the deionized water being used as the working fluid. It is found that compared with plain-wall microchannels (PM), the critical heat fluxes (CHF) in ISM are increased by 24.3%∼50.0%, and 30.8∼53.1% for SSM within the test range. The comparative study with PM reveals that SMs can significantly promote the bubbly flow. Equally important, IMs increase the effective heat transfer area while facilitating the redevelopment of the liquid film. Therefore, the heat transfer coefficient (HTC) in ISM and SSM are significantly enhanced by 44.8% ∼ 60.9% and 43.7% ∼ 68.3%, respectively. Furthermore, the connection of the microchannels promotes the mixing of the fluid and enables a more uniform flow distribution in microchannels. The interconnected slots provide the lateral expansion space for bubbles, thus suppressing the reversal flow of the bubbles. Compared with ISM, SSM could break out the long slug bubbles more effectively and prevent gigantic bubbles from forming. The two-phase pressure drop in SSM could be reduced by 23% on average compared with ISM. This work is trying to provide an improved design for microchannels to enhance the flow boiling process.
A New Battery Thermal Management System With Integrated Phase Change Materials and Cold Plate: A Numerical Study
Authors: Xiang Xinrui , Yang Ruibo , Nagarajan Ramaswamy , Sun Hongwei
Published: September 2022

Lithium-ion battery (LIB), as a renewable energy storage device has received considerable attention in recent years for its zero-emission, long life, and high energy density. However, the performance, lifespan, and safety of the LIB systems are greatly affected by their operation and storage temperatures. To ensure the batteries to work in the optimum temperature range, various battery thermal management systems (TMS) have been investigated. This research focuses on the numerical study of the thermal performance of a hybrid battery cooling system which consists of an integrated forced cooling (e.g., liquid flow in a cold plate) and phase change materials (PCM) composite — a graphite foam impregnated by paraffin wax. In the numerical model, the non-equilibrium thermodynamics model and Darcy’s law are utilized to simulate the thermal and momentum transports in the PCM composite. The heat generation rates of the battery cells are mainly determined by the depth-of-discharge (DOD) dependent internal resistance. In addition, the numerical model takes into consideration the anisotropic axial and radius thermal conductivities of the LIB battery. The results show that PCM composite plays a critical role in achieving the temperature control and maintaining the temperature difference of the LIB battery module. The melting rate of paraffin wax in the graphite foam is directly related to the coolant flowrate, coolant inlet temperature, porosity of the graphite foam, and the internal resistance of the LIB battery.
Numerical Study on the Dominant Condensation Mechanism in the Cross-Flow Transport Membrane Condenser
Authors: Al-rifai Saja , Lin Cheng-Xian
Published: September 2022

Interest in the use of transport membrane condenser (TMC) technology for heat and mass recovery from the flue gas of the power plant has been in an increase in recent years. TMC is based on using nanoporous ceramic membrane as a tube wall of the heat exchanger. The heat and mass transfer from the TMC tube bundle have been studied experimentally and numerically, and several models have been proposed to calculate the condensation rate. Researchers have reported that the transport of the flue gas through the membrane condenser involves two mechanisms: the wall condensation and the capillary condensation. However, the dominant condensation mechanism is still under debate and needs more investigation. In this study, a single-phase multi-species model coupled with mixed condensation model was used to investigate the dominant condensation mechanism at different membrane porosity and water vapor mass fraction. The Numerical simulation was executed using ANSYS/FLUENT 2021 R1 software. The mixed condensation model, which is based on the wall condensation and capillary condensation, was written in the user-defined functions (UDF). The flue gas turbulent was modeled using the shear stress transport SST k-ω turbulence model. The results showed that, at the same membrane porosity and water vapor mass fraction, the wall condensation mechanism is the dominant condensation mechanism. As the porosity increases from 0.15 to 0.50, the percentage of the capillary condensation increases from 17% to 50%, which impact in a decrease in the wall condensation percentage from 83% to 50%. Furthermore, about 69% to 87% of the total condensation rate was obtained from the wall condensation mechanism, as a result of an increase in the water vapor mass fraction from 8% to 21%. Consequently, the wall condensation was able to recover more latent heat than the capillary condensation mechanism. The convection Nusselt number decreases as the porosity increases, because of the significant reduction in the effective thermal conductivity of the nanoporous ceramic tubes.
Measuring Thermal Energy From Cross Correlated Modulation in Single Walled Carbon Nanotubes
Authors: Koh Heeyuen , Maruyama Shigeo
Published: September 2022

Recently, it has shown that the equation of motion (EOM) modified with heat diffusion process can replace the drift-diffusion terms in Langevin equation as conserving the total energy and temperature without extra thermalization process for single-walled carbon nanotubes (SWCNT) in coarse-grained (CG) model.[1] The motion of simple beads model from modified EOM maintains well-synchronized macroscopic behavior as observed in all-atom molecular dynamics simulation (AAMD) over couple of nano seconds. The same definition of heat diffusion which is derived from the cross correlated momentum is applied to suspended SWCNT in non-equilibrium molecular dynamics (NEMD) to visualize the heat energy related to macroscopic motion. The energy proportion involved in modulation by heat diffusion process has well observed by analyzing the data from simplified coordinate of trajectory of NEMD result into simple beads condition by averaging the coordinates from all atomic simulation. Further discussion on second sound and Green-Kubo relation from the trend in dispersion plot and Markovian characteristics of heat diffusion are included alongside the brief introduction of derivation.
Anisotropy of Flow and Heat Transfer of Gaseous MHD Flows in a Circular Tube Under the Control of Transverse Magnetic Field: A Preliminary Study
Authors: Zhao Qijin , Mao Baoquan , Bai Xianghua , Guo Jintao , Chen Chunlin
Published: September 2022

Given the potential application of the magnetic field to control the gaseous magnetohydrodynamic (MHD) flows in the tube, the effect of the transverse magnetic field (TMF) on the gaseous MHD flow and heat transfer characteristics in a circular tube is studied. Taking the conductive circular tube as the research object, the physical model and mathematical model are constructed by considering the influence of the non-uniformity of the TMF. The control equations are discretized and the numerical algorithm is designed under the theoretical framework of the finite volume method. On this basis, the distributions of the velocity and temperature under different magnetic induction intensities are numerically simulated, and the influence of the Hartmann number (Ha) on the flow and heat transfer characteristics is analyzed. The results show that the velocity and temperature of the flow near the Hartmann boundary layer and Robert boundary layer show anisotropy. Affected by the transition gradient of the applied TMF, a high-speed jet region appears near the Robert boundary layer. The convective heat transfer intensity of the magnetized region first decreases and then increases with the increase of the value of Ha.
Water Thermodynamic Behavior Under Influence of Electric Field: A Molecular Dynamics Study
Authors: Porterfield Malcolm , Borca-Tasciuc Diana
Published: September 2022

Water phase-change is one of the most widely used mechanisms to transfer heat, with applications in both cooling and energy conversion. Augmenting phase-change effectiveness by application of an electric field is of interest in many situations and may lead to increased system efficiency with sustainability implications. Thus, it is important to develop a better understanding of the effect of an electric field on the thermodynamic properties of water. In this work, molecular dynamics (MD) was utilized to assess two distinct water models, the TIP4P-Ew and the SWM4-NDP, for predicting the effect of an electric field on the density and the enthalpy of vaporization of water. Both water models possess rigid molecular geometry, but the SWM4-NDP model has a negatively charged Drude particle (the “NDP”) attached to the oxygen site in the water molecule, making the SWM4-NDP model polarizable. It is desired to observe how important this polarizability is to predicting density and enthalpy of vaporization. Applying an electric field in MD simulations with each water model results in increased values for both the density and enthalpy of vaporization. The magnitude of these increases are comparable between water models and increase with increasing field strength.
A Loop Heat Pipe for Vehicle CPU Cooling: Peak Performance and Partial Flooding and Dryout Regimes
Authors: Ferreira Julio , Kaviany Massoud , Dupont Vincent , de Laet Olivier , Nicolle Thomas , Yen Erik
Published: September 2022

A Loop Heat Pipe (LHP) is assembled and tested for removing up to 400 W from two vehicle CPUs, while keeping their temperature under 95°C and using a 2 m-distanced, 45°C-air cooled condenser, and working fluid R1233zd(E). The capillary evaporator wick uses a liquid artery wick supplying liquid to a sawtooth copper wall evaporator. This novel sawtooth structure extends the evaporation area, spreads the liquid, and allows for the vapor escape space, while minimizing the evaporator resistance. For the application flexibility, it is preferred to place the condenser away from the CPUs. The air-cooled condenser fan-power consumption is also important, influencing the condenser thermal resistance. The loop thermal-hydraulics are analyzed (including the wick effective thermal conductivity, permeability, and maximum capillary pressure) and modeled. These include the role of the liquid accumulation on the evaporator, and the partial, local wick dryout under statistical variation in the microlayer wick thickness. The condenser thermal resistance and pressure drop, the transfer lines pressure drops, and the accumulator volume, which can dominate and limit the overall performance, are addressed in the design selection. The model predictions are compared with the performance of the fabricated LHP under variable thermal load and CPU-condenser separation distance. Good agreements are found, under partial flooding at low thermal load, under partial dryout at high thermal load, as well as under thermal loads with peak evaporator performance. Further improvements realized in the second-generation evaporator wick is expected to raise the peak performance and the maximum thermal load significantly.
Nucleate Pool Boiling of Water on a Heater of the Size of a Capillary Length
Authors: Reed Julia , Dhir Vijay
Published: September 2022

Nucleate pool boiling of saturated water at one atmosphere pressure was investigated on a horizontal circular surface of diameter 2.7 mm. For such a surface aside from the contact angle of the surface itself, the wettability of the surrounding surface is found to have a significant effect on both the dependence of nucleate boiling heat flux on wall superheat as well as the critical heat flux. For heated surface with a contact angle of 90°, with a hydrophobic surface surrounding it, the nucleate boiling heat transfer and critical heat flux are much lower than for the hydrophilic surrounding surface. However, when the heater surface is well wetting, contact angle less than 50°, there was significant improvement that could only be seen with hydrophilic surrounding. Nucleate boiling heat transfer and critical heat flux data are found to correlate with bubble departure volume and frequency of the bubble release.
Numerical Simulation on the Flow and Heat Transfer Characteristics of the Condenser Shell Side in a 3rd Generation Nuclear Power Plant
Authors: Yan Dong , Chen Lin , Xia Yingpei , Sun Yueheng
Published: September 2022

Aiming at the improvement of the band-shaped tube bundle condenser of a 1000MW thermal power unit, this paper uses a porous media model to study the vapor phase flow and heat transfer characteristics of the condenser shell side. The distributions of streamline, velocity, temperature, air mass fraction, and heat transfer coefficient were conducted and analyzed. The back pressure of the condenser with improved band-shaped tube bundle is 5.03 kPa, which is higher than the HEI standard by 0.30 kPa. Analysis shows that the condenser air cooling zone has a better cooling effect, but there are more local vortices at the top and middle of the tube bundle module, which leads to chaos in the flow field and a decrease in heat transfer coefficient. The auxiliary steam inlet channels at the top and middle can be optimized by reducing the flow velocity in the free flow zone, thereby improving the flow field of the condenser and increasing the heat transfer coefficient. The increase of the inlet vapor velocity can enhance the heat transfer of the condenser, but also increase the inhomogeneity of heat transfer coefficient. Therefore, there is still room for optimization of the 1000MW improvement of the peripheral strip tube bundle layout. This study provides a theoretical basis for the optimization design for the condenser.
Optimal Design of Additively Manufactured Metal Lattice Heat Sinks for Electronics Cooling
Authors: Bharadwaj Bharath , Singh Prashant , Mahajan Roop L.
Published: September 2022

With increasing thermal footprint in electronic packages, metal lattices offer avenues for better thermal management in passively cooled heat sinks. Combined with the advances in metal additive manufacturing, these can be leveraged to realize complex designs that offer superior heat transfer characteristics with smaller and lighter components. In this work, design, analysis, and optimization of metal lattice-based heat sinks for passive cooling by buoyancy-driven convection is presented. Heat sinks based on three types of lattice structures — Simple Cubic, Voronoi and Octet — have been studied by varying lattice parameters such as thickness and height to obtain the optimal design. Numerical computations using the ANSYS® commercial package have been carried out and the steady state junction temperature at the base of the heat sink monitored. The Voronoi lattice structure provides the best enhancement in heat transfer with ∼18% reduction in junction-to-ambient temperature difference as compared to a standard baseline longitudinal heat sink (LHS), while simultaneously reducing the mass of the heat sink by ∼2.1 times. This behavior is attributed to the enhanced surface area, open-celled lattice structure with lower flow resistance and enhanced thermal dissipation due to local flow disturbances. Based on the junction-to-ambient temperature difference and mass of each heat sink, a Figure of Merit (FOM) is defined to quantify the relative performance of all the designs. The Voronoi lattice at 0.8 mm thickness and 25.4 mm height was found to be the optimal design. It provides the best improvement of ∼3 times compared to the baseline LHS. Also, a Design for Additive Manufacturing (DFAM) approach has been implemented. Virtual build-up simulation indicated suitability of the design for fabrication. The predicted deviation after printing was within the commercially acceptable tolerance limits for use in applications. The workflow presented here from design to analysis, optimization and preparation for fabrication is useful for rapid development of customized passive cooling solutions and determination of optimal designs. We believe that the analysis and methodology presented in this paper would be helpful in the development of better thermal management devices aided by additive manufacturing in future.
Analysis of Corner Radius on the Free Oscillating Cylinder With Heat Transfer and Flow Pattern at Low Reynolds Number
Authors: Sarout Yuvraj , Islam Md Didarul , Fatt Yap Yit , Janajreh Isam
Published: September 2022

Flow-induced vibration (FIV) of the modified single-cylinder with a change in corner radius has been investigated in a laminar flow regime with Re = 100 and Pr = 0.7. The corner radius (r: corner radius, :R cylinder characteristic length) is changed from 1 to 0 and two angles α; 0° and 45° are used. The Cylinder is elastically supported with heating at a constant temperature at the boundaries. Vibrations are restricted to the transverse direction. Computation is carried out with a fixed mass ratio m* = 10 and varying reduced velocity Ur = 2 ∼ 8. The two-dimensional incompressible Navier-Stokes equations and energy equations are coupled together. Navier stokes equation used with FIV equation of elastically supported cylinder to have flow solutions. Lock-in synchronization can be observed at Ur = 5 and Re = 100 at r* = 1 which leads to severe vibration and maximum vibrational amplitude A/D while amplitude modulation has been observed at Ur = 5 for the square cylinder. Based on the mode of vibration whole study has been divided into 4 ranges of vibration. Mode-I, where the amplitude is very low; Mode-II, fluctuating amplitude known as hysteresis (Beating); Mode-III; amplitude is at the maximum because of lock-in synchronization; Mode-IV, normal vibrational amplitude. Different modes are compared with the change in Ur, r* and α. The effect of Ur is visible on the Nusselt number as more vibration leads to a high value of averaged Nusselt number NuAvg. Vortex shedding is changed from C(2S) to 2S as the corner radius is modified. Results give a deep insight into heat transfer getting changed by changing three different parameters and will make a base for future study of tube bundles in heat exchangers with FIV.
Improved Femtosecond 3D Light Field Lithography With a Phase-Controlled Spatial Light Modulator
Authors: Jakkinapalli Aravind , Wen Sy-Bor
Published: September 2022

Through years of development, we have successfully demonstrated 3D light field lithography with UV continuous light. We recently combined this approach with femtosecond laser sources as two-photon femtosecond 3D light lithography. It is found that consistent results can happen under limited conditions with this direct combination. Our theoretical analysis reported last year shows that the experimental difficulty can be attributed to digital micro-mirror devices (DMD) and microlens arrays (MLA) used in the current 3D light field projection. Though they can control the propagation directions and interact at designed 3D locations, rays from such a system diverge with respect to the propagation distance. As a result, 3D voxel intensity in the 3D projection changes as a function of the separation distance with respect to the MLA in the 3D projection. To solve this problem, we replace the combination of DMD and MLA with a phase-controlled spatial light modulator. With a lab-developed algorithm, a single femtosecond laser pulse can generate up to a million sub-rays through the phase-controlled spatial light modulator. These sub-rays with a precisely controlled propagation direction can intersect at designed 3D locations as voxels for 3D virtual object constructions. Moreover, these sub-rays have minimum divergence angles to ensure that the voxel intensities are maintained consistently at each 3D location. We also demonstrated that versatile 3D patterns could be generated with two-photon femtosecond 3D light field lithography based on this innovative approach.
Buoyancy-Driven Convection in Additively Manufactured Cubic Lattices
Authors: Singh Prashant , Phanikumar Mantha S. , Mahajan Roop L.
Published: September 2022

We present an experimental study on buoyancy-driven convection transport in additively manufactured lattices comprising of cubic unit cells, where we have studied the effect of lattice aspect ratio (width-to-height ratio) and heating orientation with respect to the gravity vector. The lattices were manufactured via Binder jetting process in Stainless Steel 420 (with 40% bronze infiltration). The solid-phase thermal conductivity was measured on a solid sample manufactured through the same technique and was found to be 20.8 W/mK. Each lattice configuration had a porosity of 0.87. These lattices with aspect ratio varying from 0.5 to 2 and three different heating orientations, viz. bottom wall (0°), side wall (90°), and top wall (180°) heating, were tested for Rayleigh numbers ranging from 105 to 4 × 105. We found that the lowest aspect ratio lattice had the highest convective heat transfer coefficient for all three heating orientations. Further, an inter-comparison of the heating orientations at a fixed lattice aspect ratio revealed that the sideways heating orientation (90°) had the highest heat transfer, followed by bottom wall (0°) and top wall heating orientations (180°).
Supplemental Material: A tool to distinguish magmatic from secondarily recrystallized carbonatites—Calcite/apatite rare earth element partitioning
Authors: Sartori Gino , al. et
Published: September 2022

Methods and materials, detailed descriptions of experiments and experimental and natural compositions. 
Supplemental Material: Kovdor to Oldoinyo Lengai—The missing link in carbonatitic magma evolution
Authors: Vasyukova Olga V. , al. et
Published: September 2022

Methods, leaked experiments, and tables.  
Delayed Functional Independence After Neurothrombectomy (DEFIANT) score: analysis of the Trevo Retriever Registry
Authors: Jadhav Ashutosh P , Desai Shashvat M , Gupta Rishi , Baxter Blaise W , Bartolini Bruno , Krajina Antonin , English Joey D , Nogueira Raul G , Liebeskind David S , Veznedaroglu Erol , Budzik Ronald F
Published: September 2022

Background

Chronological heterogeneity in neurological improvement after endovascular thrombectomy (EVT) for large vessel occlusion (LVO) stroke is commonly observed in clinical practice. Understanding the temporal progression of functional independence after EVT, especially delayed functional independence in patients who do not improve early, is essential for prognostication and rehabilitation. We aim to determine the incidence of early functional independence (EFI) and delayed functional independence (DFI), identify associated predictors after EVT, and develop the Delayed Functional Independence After Neurothrombectomy (DEFIANT) score.

Methods

Demographic, clinical, radiological, treatment, and procedural information were analyzed from the Trevo Registry (patients undergoing EVT due to anterior LVO using the Trevo stent retriever). Incidence and predictors of EFI (modified Rankin Scale (mRS) score 0–2 at discharge) and DFI (mRS score 0–2 at 90 days in non-EFI patients) were analyzed.

Results

A total of 1623 patients met study criteria. EFI was observed in 45% (730) of patients. Among surviving non-EFI patients (884), DFI was observed in 35% (308). Younger age (p=0.003), lower discharge National Institutes of Health Stroke Scale (NIHSS) score (p<0.0001), and absence of any hemorrhage (p=0.021) were independent predictors of DFI. After age 60, the probability of DFI declines significantly with 5 year age increments (approximately 7% decline for every 5 years; p(DFI)= 1.3559–0.0699, p for slope=0.001). The DEFIANT score is available online (https://bit.ly/3KZRVq5).

Conclusion

Approximately 45% of patients experience EFI. About one-third of non-early improvers experience DFI. Younger age, lower discharge NIHSS score, and absence of any hemorrhage were independent predictors of DFI among non-early improvers.