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Purpose: While the individual impacts of long-term residence and food insecurity on overweight/obesity are well-documented, their combined effect on immigrants' weight status is less understood. This study examines the interaction between length of residence and food insecurity in predicting overweight/obesity among immigrants and investigates whether this relationship is gender-specific. Design: A national cross-sectional survey. Setting: The 2017-2018 Canadian Community Health Survey. Subjects: Immigrants aged 18 and older (N = 13 680). Measures: All focal variables were self-reported. Analysis: Logistic regression models were employed. Results: Long-term immigrants were more likely to report overweight/obesity than their short-term counterparts (OR = 1.39; P <.001). Moreover, immigrants from food-insecure households were at a higher risk of reporting overweight/obesity (OR = 1.27; P <.05) compared to those from food-secure households. The analysis further revealed that food insecurity exacerbated the detrimental association between length of residence and overweight/obesity in men (OR = 2.63; P <.01) but not in women (OR =.66; P >.05). Conclusion: The findings suggest that long-term immigrant men may be especially susceptible to the compounded chronic stressors of extended residence and food insecurity. Health professionals and policymakers should advocate for psychosocial resources to help mitigate these adverse effects and support the well-being of immigrant populations. [ABSTRACT FROM AUTHOR]

AbstractThe performance of recuperative printed circuit heat exchangers is critical in supercritical CO2 (sCO2) power generation applications. This article presents a three-dimensional numerical model of sCO2 flowing in a printed circuit heat exchanger and investigates its thermohydraulic performance under different operation conditions. The simulations employ the standard k-ε turbulent model, and consider entrance effects, conjugate heat transfer, real gas thermophysical properties and buoyancy effects. The heat exchanger operation parameters cover mass flux from 254.6 to 1273.2 kg/m2s, inlet temperature 50–150 °C and outlet pressure 100–250 bar on the cold side, and 300–500 °C and 75–150 bar on the hot side. Results show that increasing CO2 mass flux leads to a significantly increased heat transfer coefficient, a slight increase in temperature difference between the hot and cold CO2, as well as larger pressure drop and lower friction factor on both sides. Increasing the cold CO2 pressure, decreasing the cold CO2 temperature, and increasing the hot CO2 temperature result in a higher heat transfer rate of the heat exchanger. Increasing the CO2 temperature on each side causes increased pressure drops on both sides. Increasing the CO2 pressure on each side reduces the pressure drop on each side. [ABSTRACT FROM AUTHOR]

Purpose: Despite a growing body of literature on the link between residential mobility and suicidal ideation, research into potential mediating or moderating factors, especially among socioeconomically disadvantaged populations, is sparse. This study explores the mediating and moderating roles of food insecurity in the relationship between residential mobility and suicidal ideation in Indigenous Canadian adults. Methods: Data from the 2017 Aboriginal Peoples Survey, which represent a national sample of off-reserve First Nations peoples, Métis, and Inuit in Canada (N = 16,214), were analyzed using logistic regression models. Results: Food insecurity partially mediated the association between residential mobility in the past 5 years and increased suicidal ideation risk among Indigenous adults. Moreover, food insecurity intensified the adverse link between residential mobility during this same timeframe and suicidal ideation. Yet, while food insecurity did mediate the adverse relationship between residential mobility in the past year and suicidal ideation, it did not function as a moderator. Conclusion: The results emphasize that food insecurity, as a systemic challenge, acts as both a partial mediator and, in some circumstances, an amplifier of the detrimental impacts of residential mobility on suicidal ideation. [ABSTRACT FROM AUTHOR]

This study examined the moderating role of perceived community belonging in the relationship between childhood abuse and health and well-being outcomes among Canadian individuals aged 55 and older. Using data from the 2014 Canadian General Social Survey (n = 14,416), multiple linear regression models revealed that women who experienced either childhood physical or sexual abuse reported poorer self-rated general and mental health, as well as lower life satisfaction, compared to those without such histories. The most pronounced effects were observed among women who experienced both types of abuse. For men, a similar pattern was evident only for those who experienced childhood physical abuse. Notably, among women, a strong sense of community belonging lessened the negative effects of both types of childhood abuse on all examined outcomes. These findings underscore the protective role of perceived community belonging against the consequences of childhood abuse for older women. They illuminate the crucial role of gerontological social workers and scholars in promoting community integration and support. Focusing on these areas, especially for those with traumatic histories, can potentially improve their overall health and well-being. [ABSTRACT FROM AUTHOR]

The present study asks: Is disability associated with suicidal ideation among Indigenous adults in Canada? And if so, do cultural resources—as measured by cultural identity affect, cultural group belonging, cultural engagement, and cultural exploration—modify this association? Data were from a nationally representative sample of First Nations peoples living off-reserve, Métis, and Inuit across Canada—the 2017 Aboriginal Peoples Survey (N = 16,125). A series of weighted logistic regression models were performed. Indigenous adults with disabilities were significantly more likely than those without disabilities to report suicidal ideation, even after controlling for socio-demographic characteristics and physical and mental health conditions. At the same time, people with multiple disabilities were at greater risk for suicidal ideation, with the largest association among those with five or more disabilities. Furthermore, the detrimental association between disability status and suicidal ideation attenuated among those who reported cultural group belonging. In a similar vein, the buffering role of cultural group belonging was also observed in the association between the number of disabilities and suicidal ideation. This study provides compelling evidence that disability is a risk factor for suicidal ideation among Indigenous adults and that cultural group belonging plays a stress-buffering role in this relationship. [ABSTRACT FROM AUTHOR]

Despite growing interest in the health disparities associated with food insecurity, research focusing on Indigenous peoples has been limited, especially in studies using nationally representative samples. This study investigates the association between food insecurity and various health outcomes – self-rated general and mental health, chronic health conditions, suicidal ideation, and obesity – among Indigenous peoples in Canada. It also explores the potential moderating effects of culture-based resources, which include cultural identity affect, cultural group belonging, cultural engagement, and cultural exploration. The study utilized data from the 2017 Aboriginal Peoples Survey, a nationally representative sample of First Nations individuals living off-reserve, Métis, and Inuit across Canada (N = 15 ,533). Logistic regression models were used to analyze the data. Food insecurity was negatively associated with all examined health outcomes. Culture-based resources demonstrated a mixture of anticipated and unexpected effects on these relationships. Consistent with the stress process model, cultural group belonging mitigated the negative impact of food insecurity on all health outcomes. A similar pattern was observed for cultural engagement. However, contrary to expectations from the stress-buffering perspective, little evidence was found to support the moderating effects of cultural identity affect and cultural exploration. The results underscore the detrimental effects of food insecurity on the health of Indigenous peoples in Canada and suggest that culture-based resources, particularly cultural group belonging, play a crucial role in mitigating health disparities. [ABSTRACT FROM AUTHOR]

AbstractObjectivesParticipants and methodsResultsConclusionsResearch increasingly focuses on the mental health implications of both actual and perceived weight, particularly among post-secondary students. Considering their unique socio-cultural context and the frequent oversight in research, this study examines these implications specifically among Canadian Indigenous post-secondary students. Recent evidence indicates that students with normal weight may also experience increased mental health risks due to negative weight perceptions. Therefore, this study explores the independent and combined effects of actual and perceived weight on the mental health of this group.This study utilized data from the 2017 Aboriginal Peoples Survey, a nationally representative sample of First Nations peoples living off-reserve, Métis, and Inuit. The focus was on Canadian Indigenous post-secondary students aged 19-34 years (n = 1,518). Logistic regression models, stratified by sex, were employed to analyze the data.Perceptions of being overweight were linked to a higher risk of mood and anxiety disorders, poor self-rated mental health, and suicidal ideation among female students. This pattern was less evident among male students. Notably, female students who were overweight and perceived themselves as such were more likely to report poor mental health across all four indicators examined. In contrast, male students exhibited a less clear pattern. Diverging from recent studies, the findings indicated less robust mental health disparities among students with normal weight who perceived themselves as overweight, potentially due to the insufficient cell size of this category among Indigenous post-secondary students.The study highlights the complex interplay between actual and perceived weight and its impact on mental health, particularly among female Indigenous post-secondary students. [ABSTRACT FROM AUTHOR]

Purpose: This study examines the moderating role of perceived community belonging in the association between sexual orientation and various health and well-being outcomes. Design: A national cross-sectional survey. Setting: Confidential microdata from the 2021 Canadian Community Health Survey. Subjects: Individuals aged 15 and older, with a sample size ranging from 43,000 to 44,100. Measures: Sexual orientation, health and well-being outcomes, and sense of community belonging were all self-reported. Outcomes included self-rated general and mental health, depressive symptoms, and life satisfaction. Analysis: A series of multiple linear regression models. Results: Compared to heterosexual individuals, bisexual individuals reported poorer self-rated general health (b =.402, P <.001 for men; b =.454, P <.001 for women) and mental health (b =.520, P <.001 for men; b =.643, P <.001 for women), higher depressive symptoms (b = 2.140, P <.001 for men; b = 2.685, P <.001 for women), and lower life satisfaction (b =.383, P <.05 for men; b =.842, P <.001 for women). Few disparities were observed among gay men and lesbians. Contrary to some recent findings, no disparities were observed among individuals uncertain about their sexual orientation or those who chose not to disclose it, even without controlling for covariates. A stronger sense of community belonging mitigated the disadvantages associated with self-rated general health (b = -.276, P <.01) and depressive symptoms (b = -.983, P <.01) for gay men, and life satisfaction (b = -.621, P <.01) for lesbians. Conclusion: This study is among the first to highlight the stress-buffering role of community belonging in the association between sexual orientation and health and well-being outcomes. [ABSTRACT FROM AUTHOR]

Heat exchangers for supercritical CO2 power generation and waste heat to power conversion systems have a significant impact on the overall cycle efficiency and system footprint. Key challenges for supercritical CO2 heat exchangers include ability to withstand high temperature and high pressure (typical temperature range of heat source 350 to 800 °C and typical required operating pressure range 150 to 300 bars), and large pressure differential between fluid streams. Other requirements are low pressure drop, high effectiveness and high reliability under thermal cycling. This paper presents recent developments in supercritical CO2 heat exchangers in terms of material selection, design, manufacture, and operation. Since heat exchangers represent a significant portion of the total system cost, another key challenge is to find a compromise between the heat exchanger type, cost, durability, and performance. This paper explores heat exchanger technologies, manufacturing techniques and materials for high temperature and high pressure heat exchangers for supercritical CO2 applications. It also identifies technology gaps and research needs to accelerate the development of effective designs to facilitate the commercialization of both supercritical CO2 heat exchanger technologies and power cycles. [ABSTRACT FROM AUTHOR]

This study investigates the association between financial strain and psychological distress among middle-aged and older adults, exploring how this association is mediated by sleep problems and moderated by marital status. A subsample of 12,095 adults aged 50 and older was selected from the 2018 National Health Interview Survey. Results showed that financial strain was associated with higher psychological distress, and sleep problems partially mediated this association. Marital status moderated the association between sleep problems and psychological distress, and between financial strain and psychological distress, but not between financial strain and sleep problems. These findings partially support the stress-buffering role of marriage. The study offers valuable insights into the complex relationship between financial strain, sleep problems, marital status, and psychological distress among middle-aged and older adults in the United States, highlighting the need for interventions targeting financial stressors and sleep problems, especially for unmarried individuals, to improve mental health outcomes in this population. [ABSTRACT FROM AUTHOR]

Supercritical CO2 power systems offer the potential of reduced system footprint and improved thermal efficiency, through the development and adoption of compact heat exchangers. Among these heat exchangers, the microtube, printed circuit, and plate heat exchangers are emerging as the most promising technologies for heat addition to the cycle, heat recuperation and heat rejection, respectively. To investigate the performance of supercritical CO2 recuperated Brayton cycle for heat to power conversion, simulation models of the heater, recuperator and cooler were developed using the distributed modeling approach and the ε-NTU method and then integrated with turbomachinery models to form the cycle model. The influences of flow rates of the heat carrier, cooling and working fluids on the heat exchanger performance and the integrated system were investigated. For the studied power system and under the off-design operating conditions, the net thermal efficiency of the cycle varies between 14.1% and 16.8%. Results show that increasing in the working fluid flow rate remains the net power output of the cycle but decreases the net cycle thermal efficiency, while increasing in the heat carrier fluid increases both, and the increase of cooling fluid increases the net power output but maintains the net thermal efficiency. [ABSTRACT FROM AUTHOR]

The present study examines (1) whether perceived life stress mediates the associations between length of residence in Canada and self-rated mental health and general health and (2) how these processes differ across levels of perceived local community belonging. Data are from the 2017–2018 Canadian Community Health Survey (N = 14,570)—a nationally representative survey collected by Statistics Canada. Simple mediation and moderated mediation models are employed. The simple mediated associations are evaluated first and found to be statistically significant for both self-rated mental health (b = 0.046, 95% PBCI = 0.035, 0.058) and general health (b = 0.045, 95% PBCI = 0.034, 0.056). Moderated mediation analysis then reveals that while perceived local community belonging does not moderate the effects of length of residence on perceived life stress, it does moderate the effects of perceived life stress on self-rated mental health (b = − 0.042, 95% PBCI = − 0.057, − 0.028) and general health (b = − 0.026, 95% PBCI = − 0.042, − 0.011), suggesting that the adverse associations between perceived life stress and self-rated mental health and general health are weaker among immigrants with greater perceived local community belonging. Consistent with the predictions, the indirect effects are significant at all levels of local community belonging. Findings from this study highlight the need to focus more research and policy interventions on community-based coping resources. [ABSTRACT FROM AUTHOR]

Intracranial aneurysm (IA) is a prevalent disease that poses a significant threat to human health. The use of computed tomography angiography (CTA) as a diagnostic tool for IAs remains time-consuming and challenging. Deep neural networks (DNNs) have made significant advancements in the field of medical image segmentation. Nevertheless, training large-scale DNNs demands substantial quantities of high-quality labeled data, making the annotation of numerous brain CTA scans a challenging endeavor. To address these challenges and effectively develop a robust IAs segmentation model from a large amount of unlabeled training data, we propose a triple learning framework (TLF). The framework primarily consists of three learning paradigms: pseudo-supervised learning, contrastive learning, and confident learning. This paper introduces an enhanced mean teacher model and voxel-selective strategy to conduct pseudo-supervised learning on unreliable labeled training data. Concurrently, we construct the positive and negative training pairs within the high-level semantic feature space to improve the overall learning efficiency of the TLF through contrastive learning. In addition, a multi-scale confident learning is proposed to correct unreliable labels, which enables the acquisition of broader local structural information instead of relying on individual voxels. To evaluate the effectiveness of our method, we conducted extensive experiments on a self-built database of hundreds of cases of brain CTA scans with IAs. Experimental results demonstrate that our method can effectively learn a robust CTA scan-based IAs segmentation model using unreliable labeled data, outperforming state-of-the-art methods in terms of segmentation accuracy. Codes are released at https://github.com/XueShuangqian/TLF. • Triple learning collaborative training for intracranial aneurysm segmentation. • Applying multi-scale confident learning to improve the accuracy of label correction. • Applying voxel-selective strategy to enhance the effectiveness of information regions. • Building a database named IA-CTA for intracranial aneurysm research. [ABSTRACT FROM AUTHOR]

While prior research has well-documented the detrimental effect of cyberbullying victimization on health and well-being among children and adolescents, less is known about whether the same adverse pattern can be observed among adults. Moreover, it is unclear about what psychosocial resources might moderate this association. The present study uses a nationally representative cross-sectional survey—2014 Canadian General Social Survey (N = 17,548)—to examine three research questions. First, is cyberbullying victimization associated with adults' self-rated health, mental health, and life satisfaction? Second, how does religiosity—religious service attendance and religious beliefs—moderate this association? Third, do any observed patterns further differ for men and women? Through a series of logistic and ordinary least squares regression models, the results show that adults who experienced cyberbullying victimization in the past 5 years are more likely to report poor self-rated health and mental health compared to those who did not experience cyberbullying victimization in the past 5 years. Likewise, cyberbullying victimization is also associated with lower levels of life satisfaction. In addition, the adverse associations of cyberbullying victimization in the past 5 years with self-rated health and life satisfaction are weaker among those who attended religious service at least once a week in the past twelve months. A similar pattern is observed for the buffering effect of viewing religious beliefs as very important in the adverse association of cyberbullying victimization in the past 5 years with self-rated life satisfaction. There is also evidence suggesting the gendered buffering effect of the importance of religious beliefs in the association between cyberbullying victimization and self-rated health. This study makes important empirical and theoretical contributions to the growing field of research on the association between cyberbullying victimization and health and well-being and to our understanding of how religion matters to individuals dealing with stressful experiences. [ABSTRACT FROM AUTHOR]

Compact recuperative heat exchangers are critical components in supercritical carbon dioxide (sCO2) waste heat to power conversion systems. To investigate their thermohydraulic performance, a model based on the segmental design and the ε-NTU method has been developed. Four different types of heat exchanger have been considered: printed circuit heat exchanger with straight channels (PCHE-SC); printed circuit heat exchanger with zigzag channels (PCHE-ZC); microtube heat exchanger (MTHE); and microtube heat exchanger with separator sheets (MTHE-SS). The performance of the heat exchangers for different fluid mass flow rates, temperatures, and lengths was investigated in terms of Nusselt number, heat transfer coefficient, friction factor, pressure drop, heat transfer rate, entropy generation rate, and augmentation entropy generation number. Results show that these parameters significantly impact on the thermohydraulic performance of compact recuperative heat exchangers and their optimal design. For the same operating conditions and equal heat transfer rate, PCHE-ZC and MTHE-SS can have a significantly smaller size than PCHE-SC and MTHE. The augmentation entropy generation number also demonstrates the improved performance and compactness that can arise from zigzag channels and separator sheets, making them suitable for demanding high pressure and temperature applications such as sCO2 heat to power conversion systems. [ABSTRACT FROM AUTHOR]

The recent advances usually mine market information from the chaotic data to conduct a stock movement prediction task. However, the current stock price movement prediction approaches mainly compute attention weighted sum of the global contextual semantic embeddings, which fails to combine local word-level or char-level ones to jointly learn news-level representation. Moreover, for Chinese stock price movement prediction task, some collected news texts are chaotic even irrelevant to the target stock. It suggests that the models need filter some news-level representations (viewed as noises) to enhance the performance. To that aim, we develop a novel stock price movement prediction network via bidirectional gated recurrent unit (GRU) network based on reinforcement learning (RL) with incorporated attention mechanism. In specific, to reduce the noise of news texts and learn news-level representation with more abundant semantics, two novel attention mechanisms respectively based on add and dot operation were first proposed in this work. We then design a novel GRU structure based on RL to filter some irrelated news-level representations (i.e., news-level noises) and capture abundant long-term dependencies. Finally, the experimental results show that the proposed model far outperforms the recent advances and achieves state-of-the-art performances. [ABSTRACT FROM AUTHOR]

Purpose: The present study examines the extent to which (mis)matched weight and weight perceptions predict adolescents' self-rated health, mental health, and life satisfaction. Design: Quantitative, cross-sectional study. Setting: Data from the 2017-2018 Canadian Community Health Survey (CCHS)—a nationally representative sample collected by Statistics Canada. Participants: Canadian adolescents aged between 12 and 17 (n = 8,081). Measures: The dependent variables are self-rated health, mental health, and life satisfaction. The independent variable is (mis)matched weight and weight perceptions. Analysis: We perform a series of ordinary least squares (OLS) regression models. Results: Overweight adolescents with overweight perceptions are associated with poorer self-rated health (b = −.546, p <.001 for boys; b = −.476, p <.001 for girls), mental health (b = −.278, p <.001 for boys; b = −.433, p <.001 for girls), and life satisfaction (b = −.544, p <.001 for boys; b = −.617, p <.001 for girls) compared to their counterparts with normal weight and normal weight perceptions. Similar patterns have also been observed among normal weight adolescents with overweight perceptions (e.g., normal weight adolescents with overweight perceptions are associated with poorer self-rated health (b = −.541, p <.01 for boys; b = −.447, p <.001 for girls)). Conclusion: Normal weight adolescents are not immune to adverse self-rated health, mental health, and life satisfaction because their weight perceptions are also a contributing factor to health and well-being consequences. [ABSTRACT FROM AUTHOR]

This study examines Taiwan's ecological footprint (EF) and its Overshoot Day from 2000 to 2018. The latest EF calculation method is used to determine the conversion rates and equivalent factors of bioproductive lands in each year to establish a database of Taiwan's EF in that period. The results reveal that Taiwan's EF was 7.69 gha/person in 2000, dropping steadily to 6.46 gha/person in 2018. Taiwan's carbon footprint accounted for about 61% of Taiwan's total EF, slightly higher than the world average (60%). The carbon footprint as a proportion of the total EF has been increasing annually. This study adopts social communication tools, such as the overshoot day and the earth clock, to promote sustainable development goals and climate change policy initiatives. Global Footprint Network (GFN) updates the overshoot day of each country in its database yearly, based on each country's EF and biocapacity. Since Taiwan is not included in GFN, this study adopts the same method and finds out that Taiwan's Overshoot Day in 2018 was March 14th, meaning that on March 14th, 2018, Taiwan exhausted all of the biological resources that its bioproductive lands can regenerate in the year. If the global population lived like Taiwanese, four Earths would be required to provide the resources used. This result not only reflects the consumption of natural resources in Taiwan, but also indicates that Taiwan should focus on sustainable development and reduce that consumption. [ABSTRACT FROM AUTHOR]

The recent advances usually attempt to mine the effective market information from the chaotic data and learn multilevel representations by using attention mechanisms to conduct a stock prediction task. However, such methods usually lack the full utilization of local semantic embedding which contains the abundant textual semantics information. Moreover, these models suffer from the severe noise diffusion in contextual embeddings from a sequence after passing through the RNN. The noises diffusion constrains the performance of the proposed methods. In this work, we propose a stock movement predictive network via incorporative attention mechanisms. The core innovation is that the incorporative attention combines local and contextual attention mechanisms to clean the contextual embeddings by using local semantics. As a result, the attention effectively reduce the noises in the constructed higher-level representations and enhance the performance. Moreover, the local semantics and context are merged into the constructed higher-level representations which provide more abundant local semantic and contextual information. The experimental results demonstrate the state-of-the-art performance of the proposed approach on tweet and historical price dataset. [ABSTRACT FROM AUTHOR]

• We proposed a forecasting framework with multiple source heterogeneous data. • We constructed a domain-specific relation map to reduce the sparsity issue in news events data. • We built a domain specific dictionary for better quantifying the text-related information. • A Hidden Mixture Gaussian Markov Model is applied for the time-series data. Most previous works on future market price forecasting only utilize the historical transaction data, while ignoring many other valuable factors. Recently, many research works propose multiple-source data-based predicting approaches in the stock market. Although the futures market and the stock market are very similar, the futures market still has its uniqueness. Most importantly, the subject matter of futures is usually commodity entities with prominent competing products or upstream, downstream industries, which can significantly influence the price. Therefore, it is essential to propose a future specific analysis framework by considering different factors. In this study, we constructed a Multi-source Heterogeneous Data Analysis (MHDA) method for future price prediction by integrating multiple-source information, i.e., trading data, news event data, and investor comments. Firstly, we first constructed a relation map to capture all related news events from upstream and downstream commodities and then built a future-specific sentiment dictionary to accurately quantify the sentiment impact of related news and investor comments during the feature extraction. Finally, we model the quantified multi-source heterogeneous information by an extended Hidden Markov Model to capture the underlying temporal dependency in the data. Evaluations on the data of palm oil futures from 2016.9 to 2017.9 show the effectiveness of our proposed framework. [ABSTRACT FROM AUTHOR]

Although a sizeable body of research has examined the labor market outcomes for sexual minority men, suggesting that gay and bisexual men earn less than their heterosexual counterparts, fewer studies have addressed whether any apparent earnings disadvantages for sexual minority men extend to economic insecurity more broadly. Using 1991–2016 U.S. General Social Survey (GSS) data, we examine three measures of economic insecurity—household income, perceived financial satisfaction, and views about family income—among gay and bisexual men. We find that most sexual minority men experience multiple types of economic insecurity with larger disparities present for bisexual men. Consistent with the labor market literature, we observe that family structure and human capital acquisition primarily accounted for economic insecurity disparities for gay men, and family structure partially explained disparities for bisexual men. [ABSTRACT FROM AUTHOR]

Lithium metal, with ultrahigh theoretical specific capacity, is considered as an ideal anode material for the lithium‐ion batteries. However, its practical application is severely plagued by the uncontrolled formation of dendritic Li. Here, a cation‐loaded porous Mg2+‐Zeolite layer is proposed to enable the dendrite‐free deposition on the surface of Li metal anode. The skeleton channels of zeolite provide the low coordinated Li+‐solvation groups, leading to the faster desolvation process at the interface. Meanwhile, anions‐involved solvation sheath induces a stable, inorganic‐rich SEI, contributing to the uniform Li+ flux through the interface. Furthermore, the co‐deposition of sustained release Mg2+ realizes a new faster migration pathway, which proactively facilitates the uniform diffusion of Li on the lithium substrate. The synergistic modulation of these kinetic processes facilitates the homogeneous Li plating/stripping behavior. Based on this synergistic mechanism, the high‐efficiency deposition with cyclic longevity exceeding 2100 h is observed in the symmetric Li/Li cell with Mg2+‐Zeolite modified anode at 1 mA cm−2. The pouch cell matched with LiFePO4 cathode fulfills a capacity retention of 88.4% after 100 cycles at a severe current density of 1 C charge/discharge. This synergistic protective mechanism can give new guidance for realizing the safe and high‐performance Li metal batteries. [ABSTRACT FROM AUTHOR]

This paper addresses distributed multi-sensor multi-object tracking based on probability hypothesis density (PHD) filter. Due to the scalar fusion weights, existing distributed fusion methods only work well in cases where the information confidence within multi-object densities (MODs) returned by local filters remains unchanged over the object state space. Therefore, severe performance degradation can be observed as, in practice, the information confidence of an MOD is usually space-varying and can be utterly different due to the limited sensor abilities and various environment impacts. We make three contributions towards addressing this problem. Firstly, we propose a heterogeneous fusion method for multi-object Poisson process (MPP) MODs. The resulting MOD has a parallelizable structure that allows multiple clusters of sub-densities to be fused independently based on different sets of heterogeneous fusion weights. Secondly, a density-based heterogeneous fusion weights design method is proposed, in which the fusion weights are determined according to the relative information confidence of MODs. Lastly, to enhance the adaptability and robustness of the proposed fusion method, we extend it to decentralized sensor networks in conjunction with consensus and flooding protocols, respectively. The implementation of the proposed fusion algorithms using Gaussian approximation is also presented. The efficacy of the proposed fusion methods is demonstrated in various numerical experiments, including a challenging scenario in which each sensor in a decentralized network has dynamic detection probability and space-varying detection accuracy. In the experiments, the proposed method significantly outperforms the state-of-the-art in distributed fusion. In fact, the Optimal Sub-Pattern Assignment (OSPA) distances returned by the proposed method are at least 38.8% less than other solutions. • Heterogeneous fusion to fuse densities with space-varying information confidence. • Knowledge-free fusion weights without knowledge of sensors and environment. • The analytic implementation in decentralized sensor networks. [ABSTRACT FROM AUTHOR]

Graphical abstract The PCE of the TiO 2 modified device improved 50.46% and shows still more than 83% after 168 h, compared to that of ZnO-based cell which decreased to less than 50%. Highlights • The PSC based on ZnO@TiO 2 NRs as ETL was prepared in ambient air (RH55%). • The PCE of the core-shell device improved 50.46% compared to that of ZnO-based cell. • The PCE of the TiO 2 modified device shows still more than 83% after 168 h. • I atoms of PbI 2 slabs bond with Ti atoms of the TiO 2 surface at PbI 2 /TiO 2 interface. Abstract The serious charge recombination originates from the thermal instability of perovskite/ZnO and the low electron injection efficiency of ZnO. It is the important issue to be improved in ZnO-based perovskite solar cell (PSC). In this paper, the core-shell structure of ZnO@TiO 2 nanorod arrays (NRs) is designed as electron transport layer (ETL) for PSC. A novel synthesis of PSC based on ZnO@TiO 2 NRs in ambient atmosphere was proposed. The photoelectric conversion efficiency (PCE) of the core-shell device is 50.46% higher than that of common ZnO nanorod device. This is due to the improved interface contact between nanorods and perovskite layer, and the suppression of charge recombination. The PCE of the TiO 2 modified device shows still more than 83% after 168 h, compared to that of the pristine one which decreased to less than 50%. This is due to TiO 2 modification which can serve as a buffer layer to avoid direct contact between perovskite films and ZnO NRs, and inhibit s the decomposition of perovskite film on ZnO NRs. Both theoretical calculation and Raman test result show that the interaction between CH 3 NH 3 PbI 3 and TiO 2 is mainly the bonding between I atoms of PbI 2 slabs and Ti atoms of the TiO 2 surface at PbI 2 /TiO 2 interface. The mechanism of carrier transport and recombination in the PSC based on ZnO and ZnO@TiO 2 NRs was also discussed. These results highlight the potential of ZnO@TiO 2 NRs as ETL for all-solid-state PSC with high efficiency and good stability. [ABSTRACT FROM AUTHOR]

Highlights • Microchannel heat sink with triangular ribs on sidewalls. • Triangular ribs can significantly improve the heat transfer performance. • Different arrangement leads to different thermohydraulic characteristics. • Geometry of rib exerts significant influence on thermohydraulic performance. • New pressure drop and heat transfer correlations are proposed. Abstract Triangular ribs mounted in the microchannel heat sink generally result in higher heat transfer coefficient, but are usually accompanied by higher pressure drop per unit length. In order to obtain some insight into the effect of geometry parameters of triangular ribs on laminar flow and heat transfer characteristics, three-dimensional conjugated heat transfer models taking account of the entrance effect, viscous heating and temperature-dependent thermophysical properties are conducted, and four non-dimensional variables related to the width, height, converging-diverging ratio and spacing of the triangular rib for both aligned and offset arrangements are designed. Effects of the geometry and arrangement of triangular ribs on thermohydraulic performance are examined by the variations of average friction factor and Nusselt number for Reynolds number (Re) ranging from 187 to 715. The studied microchannels have the same width (W c) of 0.1 mm and same depth (H c) of 0.2 mm in the constant cross-section region. The geometric parameters of aligned or offset triangular ribs are ranged in 0.025–0.4 mm for width (W r), 0.005–0.025 mm for height (H r), 0.2–5 mm for spacing (S r) and 0–1 for the width ratio of converging region to a single rib (W con / W r). Based on the total 660 computational cases of the microchannel heat sinks with triangular ribs, the correlations of average friction factor and Nusselt number are proposed, respectively for aligned and offset arrangements. For the studied Reynolds number range and geometry parameters of flow passage, the microchannel heat sinks with aligned triangular ribs present 1.03–2.01 times higher of average Nusselt number and 1.06–9.09 times larger of average friction factor, and those with offset triangular ribs show 1.01–2.16 times higher of average Nusselt number and 1.04–7.43 times larger of average friction factor, compared with the reference straight microchannel heat sink. Proposed heat transfer and friction factor correlations show good agreements with the computational results for the microchannel heat sinks within the parameter ranges of 187 ≤ Re ≤ 715, 0.25 ≤ W r / W c ≤ 4, 0.05 ≤ H r / W c ≤ 0.25, 0 ≤ W con / W r ≤ 1, and 2 ≤ S r / W c ≤ 50. [ABSTRACT FROM AUTHOR]

Highlights • Microchannel heat sinks with triangular ribs on sidewalls. • Three-dimensional numerical model of laminar flow and heat transfer. • The triangular ribs effectively prevent the decline of local heat transfer. • Different arrangements result in different local thermohydraulic characteristics. • Geometry of rib shows significant influence on local thermohydraulic performance. Abstract Triangular ribs are mounted on the parallel sidewalls of microchannels in order to reinitialize the thermal boundary layer and improve the mixing of cold and hot fluids. This paper presents a detailed numerical study on local laminar fluid flow and heat transfer characteristics in microchannel heat sinks with tandem triangular ribs for Reynolds number of 443. Three-dimensional conjugate heat transfer models considering entrance effect, viscous heating, as well as temperature-dependent thermophysical properties are employed. Water and silicon are respectively used as fluid and solid for the computational domain. Triangular ribs are attached in microchannels with either aligned or offset arrangement. Four non-dimensional geometry parameters relative to the width, height, converging-diverging ratio and spacing of triangular ribs are proposed to investigate the influence on local fluid flow and heat transfer characteristics. Velocity contour, pressure and temperature distributions are examined to demonstrate the basic fluid flow and heat transfer mechanism. Local pressure and temperature profiles are studied to show the influence of the triangular ribs on fluid flow and heat transfer process. Local friction factor and Nusselt number for different non-dimensional geometry variables are further investigated to comprehensively indicate the impact of triangular ribs. Results shows that the triangular ribs can significantly reduce the temperature rise of the heat sink base and efficiently prevent the drop of local heat transfer coefficient along the flow direction, but also result in higher local friction factor than the straight microchannel. For the studied operation conditions and geometry parameters of flow passage, the heat sink base temperature varies in the range of from 301.90 to 324.31 K, the computed pressure drop and heat transfer coefficient fluctuate from one triangular rib to the next and their amplitude and wavelength significantly depend on the geometry and arrangement of triangular ribs. Compared to the reference straight microchannel heat sink, a superior configuration considered in this paper can yield an improvement of up to 2.15 times higher of average Nusselt number. [ABSTRACT FROM AUTHOR]

In this paper, highly uniform and band gap tunable CH 3 NH 3 PbI 3-x Br x perovskite film was successfully prepared by a polymer blends (Polyvinyl Pyrrolidone/polyethylene glycol) modified sequential deposition method in ambient atmosphere. Moreover, the influences of the Br content on the surface morphology, structure, optical absorption and luminescence properties of CH 3 NH 3 PbI 3-x Br x films and the photovoltaic performance of the corresponding perovskite solar cells based on ZnO-TiO 2 nanorod arrays were investigated. The results revealed that introducing bromine ion can decrease the convert rate from PbI 2 to CH 3 NH 3 PbI 3 . Furthermore, bromine doping can expand the bang gap of the CH 3 NH 3 PbI 3 , which is benefit to the improvement of open-circuit voltage. The CH 3 NH 3 PbI 3-x Br x perovskite solar cell shows the best device performance with an open-circuit voltage ( Voc ) of 0.87 V, a short-circuit current density ( Jsc ) of 17.41 mA/cm 2 , fill factor ( FF ) of 0.6 and power conversion efficiency of 9.12% when the molar ratio of PbBr 2 /PbI 2  = 15/85. [ABSTRACT FROM AUTHOR]

The thermal-hydraulic performance of microchannel heat sinks with ribs in the interrupted transverse microchambers is studied using a three-dimensional conjugated heat transfer model and considering entrance effect, viscous heating and temperature-dependent thermophysical properties. Five different configurations of ribs and four lengths along the flow direction for every rib configuration are selected to analyze the effects of rib geometry on the thermal-hydraulic performance. The five rib configurations are rectangular, backward triangular, diamond, forward triangular and ellipsoidal, and the rib geometry parameters include expansion-constriction profile, ratio and length. The effects of rib geometry on thermal-hydraulic performance are firstly examined by the variations of friction factor and Nusselt number with Reynolds number, and corresponding correlations are proposed. Then, the conductive, convective and fluid capacitive thermal resistances are analyzed to obtain some insight into the basic heat transfer mechanism. Next, the entropy generation rates due to heat transfer and fluid friction are investigated for the analysis of the lost available work and irreversibility in the heat transfer process. Finally, the performance evaluation criteria is calculated to comprehensively assess the performance of such interrupted microchannel heat sinks with different rib geometry. For the studied operation parameters and rib geometries, the interrupted microchannel heat sinks with ribs in the transverse microchambers show a 4–31% decrease in the total thermal resistance, a 4–26% decrease in the total entropy generation rates, the maximum value 1.39 in performance evaluation criteria, compared with the straight microchannel heat sink. [ABSTRACT FROM AUTHOR]

• A robust and efficient joint sensor registration and multi-object tracking method for PHD filter to address the distributed fusion in networks where the relative positions of sensors are unknown. • The pairwise registration strategy which can transform the high-dimension optimization to low-dimension optimization for computationally efficient. • The two-step optimization method which can transform the formulated non-convex problem of the proposed method to a convex one. This paper addresses the joint sensor registration and multi-object tracking in distributed sensor networks wherein the accurate positions of sensors are unknown. Each local sensor runs the probability hypothesis density filter (PHD) in its local coordinate system, having no knowledge about the relative positions of other sensors in the network. The generalized covariance intersection (GCI) fusion rule is employed to fuse the local densities. To tackle the sensor registration problem, a cost function expressing the information discrepancy between local densities is constructed based on the GCI divergence, then the relative positions of sensors are estimated by minimizing such a cost function. As the constructed cost function leads to a high-dimension optimization problem, for computational efficiency, a pairwise sensor registration strategy is proposed which is proved equally sound with the high-dimension registration method but more computationally efficient. Lastly, we demonstrate that the formulated registration method involves a non-convex problem. To solve such a non-convex problem, a two-step optimization method is proposed which can transform the non-convex problem into a convex one. The efficacy of the proposed method is demonstrated in a challenging tracking scenario via numerical experiments. [ABSTRACT FROM AUTHOR]

Silicon thin-film is one of the most promising silicon anode materials for lithium-ion batteries, with the advantages of high cycle stability and initial coulombic efficiency. The excellent performance of silicon thin-films is due to their ultra-thin thickness (< 200 nm), but this results in their areal capacity too low to be compatible with commercial cathode materials, and only films thicker than 500 nm are practical. However, frequent volume changes in non-ultra-thin silicon films during cycling may cause layer misalignment and separation of the film from substrate. In this paper, silicon films with a thickness of ∼700 nm are prepared by magnetron sputtering on the inhomogeneous surface of a copper foil. The properties of the silicon films and mechanisms involved in the cycling process is investigated by combining experimental means during cycling with calculations of the atomic-scale amorphous lithium-silicon Zintl Phases' structural volumes before and after cycling. The results show that the volume of silicon doesn't recover after delithiation and there is still significant swelling. The cyclic process causes a superimposed expansion of the volume, but the non-uniform film substrate causes the lateral expansion stresses to offset each other, thereby retaining a relatively stable structure. At the end of 100 cycles, the specific capacity of the silicon film electrode is 1461.5 mAh g −1 (areal capacity 0.242 mAh cm−2), with a capacity retention of 64.35%, and the silicon film thickness becomes 8.5 μm. We believe that by reducing the longitudinal expansion volume or stress of the silicon film, the cycle life of the silicon film can be further optimized. [Display omitted] [ABSTRACT FROM AUTHOR]

Considerable research has established the harmful impacts of the COVID-19 pandemic on children's and adolescents' health and well-being. However, the literature has been constrained by studies using less representative samples, hindering the generalization of the findings. This study aimed to investigate the associations of employment disruption and school closures during the pandemic with suicidal ideation and behavior in children and adolescents—and to consider the potential mediating effects of child psychological and physical abuse and subsequent mental health conditions. This study used the Adolescent Behaviors and Experiences data (n = 4692) — a nationally representative survey administered by the CDC of the United States from January to June 2021. Logistic regression models were conducted to investigate the associations. A series of multiple mediation models were performed. School closures directly reduced child psychological and physical abuse and suicidal ideation and behavior. Employment disruption did not directly predict suicidal ideation and behavior but primarily through child abuse. Mental health's mediation role was significant in the associations between child psychological abuse and suicidal ideation and behavior, but no evidence suggested the same mediating pattern for the physical abuse-suicidal ideation and behavior relationship. Within the covariates, sexual orientation was the most consistent and highest risk factor. This study contributes to current knowledge on disaster impact, child abuse, and suicidal ideation and behavior, and it can also provide policy and intervention awareness for social workers. • The most recent national representative survey in the United States about children and adolescents was analyzed. • The associations between COVID-19 impacts, child abuse, mental health and four suicidality measures were investigated. • School disruptions directly reduced child psychological and physical abuse experience and suicidal ideation and behaviors. • Employment disruption did not directly predict suicidal ideation and behavior but primarily through child abuse. • Mental health's mediation role was significant between psychological abuse and suicidality but not for physical abuse. [ABSTRACT FROM AUTHOR]

The paper is focused on the investigation of the laminar flow and heat transfer characteristics in the interrupted microchannel heat sink with ribs in the transverse microchambers. A three-dimensional model based on finite volume approach and SIMPLEC algorithm is performed considering entrance effect, conjugate heat transfer, viscous heating and temperature-dependent thermo-physical properties. Five different rib configurations are considered, including rectangular, backward triangular, diamond, forward triangular and ellipsoidal. The present study firstly examines the effect of such ribs on velocity contour, pressure distribution and temperature distribution, further the local pressure drop and heat transfer characteristics in such microchannel heat sinks. Result shows that the ribs in the transverse microchambers can effectively prevent the decline of local heat transfer coefficient along the flow direction. Secondly, the average friction factor and Nusselt number for such microchannel heat sinks have been studied. Results show that for Reynolds number ranging from 187 to 715, there is a 24–57% increase in the Nusselt number for the interrupted microchannel heat sinks with ribs, while the friction factor increased by 3–70%, comparing with the straight microchannel heat sink. Finally, based on the performance evaluation criteria, the performance of such microchannel heat sink has been comprehensively evaluated. Results shows that for the studied Reynolds number range and microchannel geometries in this paper, the interrupted microchannel heat sink with ellipsoidal ribs in the transverse microchambers shows the best heat transfer performance, with maximum 1.39 of performance evaluation criteria. [ABSTRACT FROM AUTHOR]

In this first part of a three-part study, a three-dimensional numerical model has been conducted to study the heat transfer characteristics of laminar flow in microchannel heat sinks with different geometric fan-shaped ribs on sidewalls for Reynolds number ranging from 187 to 715. The numerical model considers entrance effect, conjugate heat transfer, viscous heating and temperature-dependent thermo-physical properties. The water and silicon are used as fluid and solid for the computational domain. The computations base on the finite volume method and implement the SIMPLEC algorithm. The microchannel has the width of 0.1 mm and depth of 0.2 mm in the constant cross-section region. The geometric parameters include the width (0.05–0.4 mm), height (0.005–0.025 mm) and spacing (0.2–5 mm) of aligned or offset fan-shaped ribs. The present study firstly examines the effect of fan-shaped ribs on velocity contour, temperature distribution and local heat transfer characteristics for laminar flow in such microchannel heat sinks. It is apparent that the fan-shaped ribs can effectively prevent the decline of local heat transfer coefficient along the flow direction. Secondly, the average Nusselt number and the total thermal resistance for such microchannel heat sinks have been studied. Results show that the height and spacing of fan-shaped ribs have significant influences on the heat transfer characteristics, while the width of ribs shows less. For the microchannel heat sinks with lower height and lager spacing of fan-shaped ribs, the aligned arrangement shows higher heat transfer coefficient than the offset one. For the studied Reynolds number range and geometric parameters of fan-shaped ribs, there are a 6–101% increase in average Nusselt number and a 3–40% decrease in total thermal resistance for the microchannel heat sink with aligned fan-shaped ribs, while a 4–103% increase in average Nusselt number and a 2–42% decrease in total thermal resistance for the microchannel heat sink with offset fan-shaped ribs, comparing with the smooth one. New heat transfer correlations for such microchannel heat sinks are developed, which fit the present data with a mean absolute error of 2.5% for the ones with aligned fan-shaped ribs and 3.8% for the ones with offset fan-shaped ribs. [ABSTRACT FROM AUTHOR]

In order to comprehensively assess the performance of microchannel heat sink with fan-shaped ribs on sidewalls, this third part of a three-part study focuses on the relationship between thermal resistance and pumping power, and further the entropy generation rate and performance evaluation criteria, with water and silicon used as fluid and solid for the computational domain. The microchannel has the width of 0.1 mm and depth of 0.2 mm in the constant cross-section region. The geometric parameters include the width (0.05–0.4 mm), height (0.005–0.025 mm) and spacing (0.2–5 mm) of aligned or offset fan-shaped ribs. For deep insight into the basic mechanisms and properties of such heat sinks, the entropy generation rate due to heat transfer and fluid friction are separately studied. Results show that the fan-shaped ribs can lead to better comprehensive performance and the geometric parameters of fan-shaped ribs have a significant influence on the performance of such microchannel heat sinks. With the increase of the rib’s height, the microchannel heat sinks with offset fan-shaped ribs gradually perform better than the ones with aligned fan-shaped ribs. With the decrease of the rib’s spacing, the comprehensive performance firstly becomes better and then gradually deteriorates. For the microchannel heat sink with large rib’s height and small rib’s spacing, the increase of Reynolds number can lead to tremendously increase of entropy generation rate due to fluid friction, which can withdraw the decrease of entropy generation rate due to heat transfer and lead to the increase of total entropy generation rate, making the comprehensive performance worse than the smooth one. For Reynolds number ranging from 187 to 715 and studied geometric parameters, the best microchannel heat sink shows a 32% decrease in entropy generation rate and 1.33 in performance evaluation criteria, comparing with the smooth one. [ABSTRACT FROM AUTHOR]

This second part of a three-part study concerns pressure drop of laminar flow in microchannel heat sinks with water and silicon used as fluid and solid for the computational domain. In the rectangular microchannel with width of 0.1 mm and depth of 0.2 mm, the repeating aligned or offset fan-shaped ribs are mounted to the channel sidewalls. To examine the influence of fan-shaped rib’s geometry on thermal and hydraulic characteristics of laminar flow, three non-dimensional variables, representing the width (0.05–0.4 mm), height (0.005–0.025 mm) and spacing (0.2–5 mm) of fan-shaped ribs are designed. The present study firstly presents the pressure distributions in microchannels to analyze the local hydraulic characteristics, and then examines the local pressure and friction factor along the flow direction for different geometry of fan-shaped ribs. Results show that the fan-shaped ribs can lead to large increase of local pressure in comparison with the smooth microchannel, especially for the aligned fan-shaped ribs. Further, the effect of fan-shaped ribs’ geometry on the average friction factor has been investigated. Results show that with the increase of fan-shaped ribs’ width, the friction factor ratio of the studied microchannels to the smooth one firstly decreases and then increases. The increase of fan-shaped ribs’ height and decrease of ribs’ spacing can lead to the extreme increase of average friction factor, especially for the microchannels with aligned fan-shaped ribs. For Reynolds number ranging from 187 to 715, the microchannels with aligned fan-shaped ribs show the average friction factor 1.1–8.28 times larger than the smooth one, while those with offset fan-shaped ribs show 1.22–6.27 times higher. New pressure drop correlations for such microchannel heat sinks are developed, which fit the present data with a mean absolute error of 13.2% for the ones with aligned fan-shaped ribs and 13.5% for the ones with offset fan-shaped ribs. [ABSTRACT FROM AUTHOR]

Gas–liquid two-phase intermittent flow pattern and frictional pressure drop in new silicon multi-microchannel were investigated experimentally by means of the IDT high-speed camera mounted together with a Nikon microscope. Each test section consisted of 10 parallel microchannels with 0.1 mm wide and 0.2 mm deep in constant cross-section segment and each microchannel consisted of an array of periodic reentrant cavities. The major two-phase flow pattern observed was intermittent in the test sections, and the intermittent sub regimes in the new microchannels were different from those displayed in the rectangular straight microchannel. Using nitrogen and deionized water as working fluids, the intermittent sub regime maps for the new multi-microchannel were obtained. Meanwhile, the pressure drops were compared with several existing correlations based on the homogeneous or separated mixture assumption. Results show that the homogeneous flow model cannot predict the two-phase pressure drop data well, while the separated flow model is proposed to provide a better prediction of the two-phase frictional pressure drop. Among the separated flow models investigated, the best two correlations of C value can provide mean deviations within less than 16% for all the three microchannels and all the predictions lie in the bound of ±30%. [ABSTRACT FROM AUTHOR]

In order to reduce the cost of thermal energy recovery, a packed bed closed loop thermal energy storage system has been proposed and is investigated. The main components of the system include a closed air cycle, a heat exchanger, and a packed bed storage column. This paper is aimed at analyzing the performance of the packed bed in the system. Packed bed column experiments have been carried out to provide a basic understanding of the thermal energy storage process in the closed loop system with different flow directions in the packed bed and different energy storage temperatures. The detailed temperature distributions in the interior of the packed bed and the temperature differences along the axial and radial directions are presented. The influence of flow direction within the packed bed and structure of the gas distributer on the temperature distribution are also analyzed. The performance of packed beds in the closed loop thermal energy storage system is then evaluated based on energy and exergy analyses. These experimental results would be useful in the optimal design of the structure of packed bed columns and thus closed loop thermal energy storage systems. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two-phase flow pattern in microchannel with uniform reentrant cavities. [•] Evolution characteristic for two-phase flow pattern along flow direction. [•] Correlation for describing two-phase flow pattern transition. [Copyright &y& Elsevier]

Abstract: The heat transfer enhancement of microchannel heat sinks with periodic expansion–constriction cross-sections is investigated both experimentally and numerically. Each heat sink consists of 10 parallel microchannels with 0.1mm wide and 0.2mm deep in constant cross-section segment and each microchannel consists of an array of periodic expansion–constriction cross-sections. Three-dimensional laminar numerical simulations, based on the Navier–Stokes equations and energy equation, are obtained for pressure drop and heat transfer in these microchannel heat sinks under the same experimental conditions. Multi-channel effect, entrance effect, conjugate heat transfer, viscous heating and temperature dependent properties are considered. It is found that the numerical predictions of apparent friction factor and Nusselt number are in good agreement with experimental data. The influences of periodic expansion–constriction cross sections on pressure drop, heat transfer and thermal resistance are discussed, respectively. The effects of the entrance and exit plenum regions and the lateral parts of silicon wafer on fluid flow and heat transfer are discussed. Special attentions are given to analyze the variation of thermal resistance for each term with pumping power, corresponding to three stages of heat release at the substrate of heat sink. [Copyright &y& Elsevier]

An experimental investigation has been performed on the laminar flow and heat transfer of water in trapezoidal silicon microchannels. Two three-dimensional (3D) heat transfer models have been developed to simulate the heat transfer performance under the same experimental conditions. Due to the sudden contraction, the velocity develops a little faster, which makes the pressure drop slightly lower than that of the neglected entrance and exit plenum regions. Due to the heat conduction in the lateral parts of wafer, the maximum temperature appears near the outlet of microchannel and the temperature is slightly different among the microchannels. Nearer to the lateral parts of wafer, the the temperature reaches the maximum for the sidewall later. With a given pumping power, the thermal resistance decreases as increase of the heating power at the substrate. However, the subthermal resistance proportion is nearly unchanged. With an increase of pumping power, the subthermal resistance proportion of convection increases rapidly at first, then gradually approaches an asymptote. [ABSTRACT FROM AUTHOR]

Abstract: The paper is focused on the investigation of fluid flow and heat transfer characteristics in a microchannel heat sink with offset fan-shaped reentrant cavities in sidewall. In contrast to the new microchannel heat sink, the corresponding conventional rectangular microchannel heat sink is chosen. The computational fluid dynamics is used to simulate the flow and heat transfer in the heat sinks. The steady, laminar flow and heat transfer equations are solved in a finite-volume method. The SIMPLEX method is used for the computations. The effects of flow rate and heat flux on pressure drop and heat transfer are presented. The results indicate that the microchannel heat sink with offset fan-shaped reentrant cavities in sidewall improved heat transfer performance with an acceptable pressure drop. The fluid flow and heat transfer mechanism of the new microchannel heat sink can attribute to the interaction of the increased heat transfer surface area, the redeveloping of the hydraulic and thermal boundary layers, the jet and throttling effects and the slipping over the reentrant cavities. The increased heat transfer surface area and the periodic thermal developing flow are responsible for the significant heat transfer enhancement. The jet and throttling effects enhance heat transfer, simultaneously increasing pressure drop. The slipping over the reentrant cavities reduces pressure drop, but drastically decreases heat transfer. [Copyright &y& Elsevier]

Abstract: We provide three-dimensional numerical simulations of conjugate heat transfer in the newly proposed microchannels with different structural parameters. The structural parameters include the lengths and widths of the constant cross-section region and the arcuate region. The effects of structural parameters on pressure drop and thermal resistance are presented. For the first part of the effect analysis, we study the fluid flow and heat transfer mechanism of the microchannel with aligned fan-shaped reentrant cavities in detail, which can attribute to the interaction of the increased heat transfer surface area, the redeveloping boundary layers, the jet and throttling effect and the slipping over the reentrant cavities. As to the second part of the present analysis, the effects of two design structural parameters on fluid flow and heat transfer of the new microchannel are individually prescribed and the two suitable ranges of structural parameter are found for the optimum geometric configuration. [ABSTRACT FROM AUTHOR]

[Display omitted] • Various indices and PMF were used to explore contaminations, health risk and sources of metals heavy metal. • 86.91% of sampling points in the soil belong to moderate, high and extreme ecological risks. • Carcinogenic and non-carcinogenic risks of heavy metals to the human body are insignificant. • The four main sources mainly include natural sources, transportation sources, agricultural sources and industrial sources. For the purpose of pollution assessment, human health risk assessment and quantitative source apportionment of heavy metals in cultivated soils, a total of 382 cultivated soil samples were collected from cultivated of Lanzhou in September 2019. Various indices, including pollution index (PI), Nemerow integrated pollution index (NIPI) and potential ecological risk index (RI) were used to analyze the pollution levels caused by heavy metals. Human health risk assessment, geographic information system (GIS) and positive matrix factorization (PMF) receptor modeling were employed to analyze the human health risk and source of heavy metals. The results showed that mean concentrations of Hg exceeded the national soil pollution risk screening value (GB 15618–2018). Spatially, except Cr in the study area, Pb, Cd, As, Cu, Zn and Ni have high value in Chengguan and Qilihe. Hg has high values in study areas outside Chengguan, Anning and Qilihe. The Nemerow integrated pollution index showed that the moderate and severe samples sites were 37.70% and 3.66%, respectively. The potential ecological risk indicates that most of the sampling sites are moderate risks. According to the health risk assessment results, the carcinogenic and non-carcinogenic risks of heavy metals to the human body are insignificant. Based on positive matrix factorization, there are four main sources of eight heavy metals. Pb, Cd, Zn and Ni were attributed to traffic sources; Hg were closely related to agricultural activities and medical treatment; Cr, Cu and Ni originated from natural source, As was derived from industrial activity. In this study enhance understanding of the pollution levers of heavy metals in Lanzhou cultivated soils, and also serves as reference for pollution source apportionment in other regions. [ABSTRACT FROM AUTHOR]

• Perovskite film modified by PVP/PEG mixture was prepared by a two-step method in air. • The cell with 1.5 wt%PVP/0.5 wt%PEG shows 30% PCE increasement compared with pure one. • The cell with 1.5 wt% PVP/0.5 wt%PEG retains 76% of its initial PCE value for 30 days. • The interactions between CH 3 NH 3 PbI 3 and PVP/PEG improve film quality and stability. • The bondings between perovskite and PVP/PEG increase cell efficiency and stability. The synergistic effect including the strong attraction between the C˭O in PVP and Pb2+ in perovskite, and the intense hydrogen bond between O atoms from PEG and H atoms in CH 3 NH 3 + results in the improved photoelectric conversion efficiency and air stability of PVP/PEG mixture added perovskite solar cell based on ZnO-TiO 2 nanorod arrays compared to those of the pristine one and single polymer added perovskite solar cells. ga1 The key to commercialization of organic‐inorganic lead halide perovskite solar cells (PSCs) is to achieve high photoelectric conversion efficiency (PCE) and long-term stability under ambient condition. In this paper, polymer mixture of polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) with appropriate mass ratio are incorporated into PbI 2 precursor solution in the preparation process of perovskite film via two-step sequential deposition method in air. The PCE of polymer mixture modified PSC based on ZnO@TiO 2 nanorod arrays is better than those of the PSC with single polymer（PVP or PEG）and the pristine one, and the PCE of 1.5 wt%PVP/0.5 wt%PEG modified device increased by 30% compared with that of the unmodified one, which is mainly a consequence of the better quality of perovskite film caused by the synergistic effect including the strong attraction between the C=O in PVP and Pb2+ in perovskite, and the intense hydrogen bond between O atoms from PEG and H atoms in CH 3 NH 3 +. Moreover, polymer mixture modified PSC also represents better air stability compared with the device with single polymer or the pristine one，which is largely attributed to the exceptional hygroscopicity of PVP/PEG mixture, the synergistic stabilization of perovskite structure and inhibition of ion migration by the bondings between polymer mixture and perovskite. Furthermore, the mechanism of the interaction between PVP/PEG mixture and CH 3 NH 3 PbI 3 to increase the efficiency and stability of the PSC was also studied. Our work offers an effective additive to simultaneously improve the efficiency and stability of the PSCs in high humidity environment for further commercial application. [ABSTRACT FROM AUTHOR]

Using a nationally representative survey of urban areas from China, the present study examines three research questions: (1) how are alcohol and tobacco use associated with academic performance among Chinese children and adolescents? (2) how does skipping class mediate those associations? And (3) do any observed patterns differ for boys and girls? Our results show that alcohol and tobacco use are associated with poor academic performance. However, alcohol use fully accounts for the detrimental effect of tobacco use on academic performance. Moreover, skipping class partially and fully mediates the effects of alcohol and tobacco use on poor academic performance. The adverse effect of tobacco use on academic performance is stronger for girls than boys. To improve children's and adolescents' academic performance, it is important to document the potential contributing factors. [ABSTRACT FROM AUTHOR]

Using a nationally representative survey of urban areas from China collected in 2016, we examine two research questions: (1) how is school bullying victimization associated with self-rated health and life satisfaction; and (2) how do relationships with parents, teachers, and peers mediate those associations? We find that, among students of higher primary, middle, high, and vocational schools, bullying victims are more likely to report poor self-rated health and life satisfaction, regardless of whether the victims experience traditional bullying or cyberbullying. In addition, both traditional bullying and cyberbullying victims are associated with poor relationships with parents, teachers, and peers, which, in turn, partially mediate the effect of bullying victimization on poor self-rated health and life satisfaction. The present study underscores that the impact of adults and peers might be an important mechanism contributing to the health and well-being disparities by school bullying victimization. [ABSTRACT FROM AUTHOR]

Ample work has established the adverse impact of school bullying victimization on health and well-being outcomes. However, few studies have explored the potential coping mechanisms. To address this shortcoming, the present study examines three questions. First, how is school bullying victimization associated with self-rated health and life satisfaction? Second, how do educational expectations moderate those associations? Third, do any observed patterns further differ for boys and girls? Using a nationally representative survey of urban areas from China collected in 2016, we found that traditional bullying victims were more likely than non-victims to report poor self-related health and life satisfaction We observed similar patterns for cyberbullying victims. Interestingly, traditional bullying victimization fully explained the effect of cyberbullying victimization on poor self-rated health and life satisfaction among boys. The patterns for girls remained less clear. Finally, educational expectations appeared to buffer the effect of cyberbullying victimization on poor self-rated health and life satisfaction for boys only. Overall, our findings underscored the complexity of documenting health and well-being disparities by bullying victimization. [ABSTRACT FROM AUTHOR]

• To address the tracking problem of multiple maneuvering targets in low SNR environment, a multi-Bernoulli filter based track-before-detect (MB-TBD) for multiple model (MM) is proposed. • To enhance the tracking performance of multi-Bernoulli filtering when tracking multiple maneuvering targets, a measurement driven adaptive birth distribution for MB filter is generalized to TBD measurement model. • A new likelihood based adaptive birth distribution for MB-TBD filter is proposed which is able to reduce the computational cost and eliminate the time delay during target birth. • The sequential Monte Carlo implementation of the proposed MB-TBD filtering method is presented to estimate multi-target states. In this paper, a novel multi-Bernoulli filter based track-before-detect (MB-TBD) algorithm is proposed, to solve the tracking problem of multiple maneuvering targets. We incorporate the multiple motion models into the basic MB-TBD filtering, and then derive the closed-form recursive equations including both prediction and update steps based on optimal Bayesian filtering. Moreover, to accommodate the case of unknown prior knowledge for target births, a likelihood based adaptive birth distribution for the MB-TBD is proposed. The implementation of the proposed algorithm with adaptive birth distribution is presented using sequential Monte Carlo (SMC) technique. The performance of the proposed algorithm is demonstrated in challenging scenarios including multiple highly maneuvering objects. [ABSTRACT FROM AUTHOR]

This paper investigates the thermohydraulic performance of finned-tube supercritical carbon dioxide (sCO2) gas coolers operating with refrigerant pressures near the critical point. A distributed modelling approach combined with the ε-NTU method has been developed for the simulation of the gas cooler. The heat transfer and pressure drop for each evenly divided segment are calculated using empirical correlations for Nusselt number and friction factor. The model was validated against test results and then used to investigate the influence of design and operating parameters on local and overall gas cooler performance. The results show that the refrigerant heat-transfer coefficient increases with decreasing temperature and reaches its maximum close to the pseudocritical temperature before beginning to decrease. The pressure drop increases along the flow direction with decreasing temperature. Overall performance results illustrate that higher refrigerant mass flow rate and decreasing finned-tube diameter lead to improved heat-transfer rates but also increased pressure drops. Design optimization of gas coolers should take into consideration their impact on overall refrigeration performance and life cycle cost. This is important in the drive to reduce the footprint of components, energy consumption, and environmental impacts of refrigeration and heat-pump systems. The present work provides practical guidance to the design of finned-tube gas coolers and can be used as the basis for the modelling of integrated sCO2 refrigeration and heat-pump systems. [ABSTRACT FROM AUTHOR]