Thermodynamic Analysis of a Combined Power and Ejector Refrigeration Cycle Using Zeotropic Mixtures

AbstractIn this paper, a combined power and refrigeration cycle is studied. The proposed cogeneration system consists an organic Rankine cycle and a refrigeration cycle, connected by an ejector. The performance of the combined cycle is analyzed when the system running in different working fluids, including pure working fluids, R245fa and R600a, and zeotropic mixtures, R245fa/R600a. The mass fraction of the mixtures varies from 10/90 to 70/30, and the results show that the mixtures generate more refrigeration than pure working fluids, and they have better performance under certain conditions. Besides, the effect of some thermodynamic parameters, including evaporator temperature, condenser temperature, boiler temperature and turbine outlet temperature, on the performance of the system is studied

Effects of Plants for Gravity Erosion on the Loess Gully Sidewall under Intense Rainfalls

&amp;lt;p&amp;gt;To study the mechanism of vegetation on gravity erosion may provide the theoretical basis for the design of soil and water conservation on the Loess Plateau, China. This study explores the effects of vegetation on the gravity erosion using the models of loess gully sidewall with the slope degree of 70 &amp;amp;#176; and height of 1.5 m under series of rainfall simulations, in which vegetational and bare lands were used, respectively. The experimental results are shown as follows: (1) The influence of the vegetation on the total amount of gravity erosion may be ignored. The average amount of gravity erosion for each event of rainfall on the vegetational sidewall was only decreased by 12% compared with that on the bare sidewall. (2) The plant had a positive effect on the mass failures after rainfalls. The ratio of the failure mass volume after rainfall to the total on the planted slope was almost 12%, while the ratio on the bare slope was only 1%. (3) The vegetation on the gully sidewall had different influences on the varied types of gravity erosion. Compared with those on the bare land, the average amounts of the avalanche and mudslide on the vegetational slope was decreased by 72% and 69%, respectively. In the meantime, the average amount of landslide in the vegetational slope was increased by 220% compared with that in bare slope. (4) The effects of vegetation on gravity erosion were caused by several factors. The plant roots may reinforce the soil and reduce the amount of gravity erosion, but the self-gravity of the plant and increase of the permeability on the planted slope might increase the gravity erosion. In addition, the soil permeability was increased by the plant roots, which could intensify the landslides. As a result, the plant practice was preferable for the sidewall vulnerable to mudslide. The results may be referred to analyze the mechanism of gravity erosion and design the control of mass failure.&amp;lt;/p&amp;gt; </jats:p

The paradox of pandemic mitigation? Moderating role of pandemic severity on the impact of social distancing policies: a cultural value perspective

Abstract Background Social distancing policies were of utmost importance during the early stages of the COVID-19 pandemic. These policies aimed to mitigate the severity of local outbreaks by altering public behavior. However, if the severity of the pandemic reduces, the impact of these policies on actual behavior may decrease. This study aims to examine, from a global perspective, whether the impact of social distancing policies on actual mobility is moderated by local pandemic severity and whether this moderating effect varies across cultural value contexts. Methods We combined multiple publicly available global datasets for structural equation model analysis. 17,513 rows of data from 57 countries included in all databases were analyzed. Multilevel moderated moderation models were constructed to test the hypotheses. Results More stringent policies in a region mean less regional mobility (β = -0.572, p < 0.001). However, the severity of local outbreaks negatively moderated this effect (β = -0.114, p < 0.001). When the pandemic was not severe, the influence of policy intensity on mobility weakened. Furthermore, based on Schwartz’s cultural values theory, cultural values of autonomy (β = -0.109, p = 0.011), and egalitarianism (β = -0.108, p = 0.019) reinforced the moderating effect of pandemic severity. On the other hand, cultural values of embeddedness (β = 0.119, p = 0.006) and hierarchy (β = 0.096, p = 0.029) attenuated the moderating effect. Conclusions Social distancing policies aim to reduce the severity of local pandemics; however, the findings reveal that mitigating local pandemics may reduce their impact. Future policymakers should be alert to this phenomenon and introduce appropriate incentives to respond. The results also show that the moderating role of pandemic severity varies across cultures. When policies are promoted to deal with global crises, policymakers must seriously consider the resistance and potential incentives of cultural values

The complete mitochondrial genome and phylogenetic analysis of Tipula (Yamatotipula) nova Walker, 1848 (Diptera, Tipulidae) from Qingdao, Shandong, China

The genus Tipula Linnaeus, is a large group of crane flies with more than 2400 known species from 41 subgenera. In this study, we report the first complete mitochondrial (mt) genome sequence of the subgenus Tipula (Yamatotipula), which is a circular molecule of 15,668 bp with an AT content of 77.2%. The mt genome contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a long non-coding region. Three conserved overlapping regions, 8 bp between tRNATrp and tRNACys, 7 bp between ATP8 and ATP6, and 7 bp between ND4 and ND4L, are found. Phylogenetic analysis reveals that the Tipulomorpha includes the family Trichoceridae and the Trichoceridae is sister-group to the remaining Tipulomorpha

Conflict-Based Search and Improvement Strategies for Solving a New Lexicographic Bi-Objective Multi-Agent Path Finding Problem

Multi-Agent Path Finding (MAPF) is an important problem with a variety of applications. Its aim is to find collision-free paths for agents having separate start and goal positions. This work proposes a new lexicographic bi-objective MAPF considering different task types, where agents are divided into two kinds to perform critical and acritical tasks. This is common in practical intelligent warehousing scenarios where a critical/acritical-task-performing agent (called c-agent and a-agent, respectively) may represent a full-load/no-load one or the one conducting urgent/non-urgent tasks. The primary objective is to minimize the sum-of-costs of c-agents, while the secondary objective is to minimize the sum-of-costs of a-agents. Two MAPF algorithms are modified to fit and solve the concerned problem for the first time. Moreover, four improvement strategies are embedded to the proposed algorithms and proved to be effective in solving MAPF problems with different task types