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Study on the mechanism and law of temperature,humidity and moisture content on the mechanical properties of molded fiber products

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Journal of Bioresources and Bioproducts 2024年第3期9卷 351-368页

作者： Zhiqiang Fu Tong Zhao Hu Wang Jingyi Wei Haozhe Liu Liying Duan Yan Wang Ruixiang Yan School of Light Industry Science and Engineering Tianjin University of Science and TechnologyTianjin 300457China Department of Transportation and Vehicle Engineering Tangshan UniversityTangshan 063000HebeiChina College of Mechanical Engineering Tianjin University of Science and TechnologyTianjin 300457China

The change of temperature, humidity and moisture content (MC) will lead to the change of mechanical properties of molded fiber products (MFP). However, it is difficult to decouple the effects of temperature, humidity and MC on the mechanical properties of MFP, and predict the mechanical properties of MFP during the use. In this study, the laws and mechanism of mechanical properties of MFP with ambient temperature, humidity and MC were studied. The results showed that the direct effect of temperature (20−70 °C) on mechanical properties of MFP was insignificant, and the mechanical properties of MFP were mainly changed by MC. The MC was related to ambient temperature and humidity, and the relationship between the three could be described by the modified Guggenheim-Anderson-de Boer (GAB) model (20−70 °C and 30 %–90 % relative humidity). With the increase of MC, the elastic modulus and fracture strain was increased and decreased linearly, the yield strength and failure strength were presented GaussAmp laws, and the failure strain was presented asymptotic regressed distribution law. Two fracture modes of MFP, brittle fracture and ductile fracture, were revealed by the scanning electron microscopy of the mesoscopic fiber structure of sugarcane bagasse molded fiber products. The mathematical models and the changes of fiber structure were verified by wheat straw molded fiber products and waste paper molded fiber products. This study was contributed to understand the effects and mechanism of the change of temperature, humidity and MC on the mechanical properties of MFP.

关键词： temperature Relative humidity Moisture content Molded fiber products Mechanical properties

Adhesion Performances Between Two Orthotropic Solids Influenced by temperature Increment

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Acta Mechanica Solida Sinica 2024年第3期37卷 430-443页

作者： Luo Q.-H. Zhou Y.-T. School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai 200092 China

The classical adhesive contact models belong to isothermal adhesion theories, where the effect of temperature on adhesion was neglected. However, a number of experimental results indicated that the adhesion behaviors can be significantly affected by temperature. In this paper, the two-dimensional non-slipping anisothermal adhesion behaviors between two orthotropic elastic cylinders are investigated within the framework of the Johnson–Kendall–Roberts theory. The stated problem is reduced to the coupled singular integral equations by virtue of the Fourier integral transform, which are solved analytically with the analytical function theory. The closed-form solutions for the stress fields in the presence of thermoelastic effect are obtained. The stable equilibrium state of contact system is determined by virtue of the Griffith energy balance. The effect of temperature difference on adhesion behaviors between orthotropic solids is discussed. It is found that the difference between the oscillatory and non-oscillatory solutions increases with increasing the degree of anisotropy of orthotropic materials. The oscillatory solution cannot be well approximated by the non-oscillatory solution for the orthotropic materials with relatively high anisotropy. © The Chinese Society of Theoretical and Applied Mechanics 2024.

关键词： Adhesive contact Griffith energy balance JKR model Non-slipping temperature

Combined Effect of temperature and Cadmium on Molecular Responses of Hsp70 and P-gp Genes in Crassostrea gigas

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Journal of Ocean University of China 2024年第04期23卷 1115-1120页

作者： HU Fanguang SUN Ming LIU Guangbin JING Yuanyuan CHEN Qun ZHANG Tianwen Marine Science Research Institute of Shandong Province

To evaluate the combined effect of temperature and cadmium on the molecular responses of heat shock protein 70 （hsp70）and P-glycoprotein （P-gp） in mantle,digestive gland and gills of Crassostrea gigas,oysters were exposed to combinations of five temperature levels （10,15,20,25,and 30℃） and 10μg L-1cadmium for 21 *** were sampled for mRNA quantification by qPCR,and the results showed that the P-gp gene expression changed significantly after treatment at different temperatures and different treatment *** P-gp gene expression was the highest in the digestive *** with the control group,the P-gp gene expression in cadmium treatment groups at all the different temperatures were significantly higher than the control *** control oysters （kept at 10℃during the whole experiment without cadmium） expressed low levels of hsp70,but the groups treated with cadmium displayed somewhat higher *** present study demonstrated hsp70 and P-gp played an important role in the detoxification of Cd in ***,and confirmed temperature should be considered for the assessment of Cd-induced toxicity in oysters.

关键词： temperature cadmium P-gp hsp70 Crassostrea gigas

Morphological Evolution of Self-Assembled Sodium Dodecyl Sulfate/Dodecyltrimethylammonium Bromide@Epoxy-β-Cyclodextrin Supramolecular Aggregates Induced by temperature

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Journal of Renewable Materials 2024年第4期12卷 629-641页

作者： Qingran Meng Wenwen Xu Zuobing Xiao Qinfei Ke Xingran Kou Key Laboratory of Textile Science&Technology Ministry of EducationCollege of TextilesDonghua UniversityShanghai201620China Collaborative Innovation Center of Fragrance Flavor and Cosmetics School of Perfume and Aroma Technology(Shanghai Research Institute of Fragrance&Flavour Industry)Shanghai Institute of TechnologyShanghaiChina

Bio-based cyclodextrins(CDs)are a common research object in supramolecular *** special cavity structure of CDs can form supramolecular self-assemblies such as vesicles and microcrystals through weak interaction with guest *** different forms of supramolecular self-assemblies can be transformed into each other under certain *** regulation of supramolecular self-assembly is not only helpful to understand the self-assembly principle,but also beneficial to its *** the present study,the self-assembly behavior of epoxy-β-cyclodextrin(EP-β-CD)and mixed anionic and cationic surfactant system(sodium dodecyl sulfate/dodecyltrimethylammonium bromide,SDS/DTAB)in aqueous solution was *** and particle size characterization found that the SDS/DTAB@EP-β-CD complex,as the basic building unit,self-assembled into worm-like micelles at lower temperatures and vesicles at higher *** magnetic resonance(NMR)and Fourier transform infrared spectroscopy(FT-IR)analysis revealed that the driving force for the formation of vesicles and worm-like micelles was the hydrogen bonds between EP-β-CD molecules,while water molecules played an important role in promoting vesicle formation between SDS/DTAB@EP-β-CD ***,the mechanism of the morphologic transformation of SDS/DTAB@EP-β-CD supramolecular aggregates induced by temperature was elucidated by exploring the self-assembly process,which may provide an excellent basis for the development of delivery carriers.

关键词： Epoxy-β-cyclodextrin SDS/DTAB self-assembly temperature morphological evolution

Spatiotemporal dynamics of land use/land cover(LULC)changes and its impact on land surface temperature:A case study in New Town Kolkata,eastern India

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Regional Sustainability 2024年第2期5卷 26-48页

作者： Bubun MAHATA Siba Sankar SAHU Archishman SARDAR Laxmikanta RANA Mukul MAITY Department of Geography Ravenshaw UniversityCuttack753003India Department of Geography Sri Krushna Chandra Gajapati(Autonomous)CollegeParalakhemundi761200India

Rapid urbanization creates complexity,results in dynamic changes in land and environment,and influences the land surface temperature(LST)in fast-developing *** this study,we examined the impact of land use/land cover(LULC)changes on LST and determined the intensity of urban heat island(UHI)in New Town Kolkata(a smart city),eastern India,from 1991 to 2021 at 10-a intervals using various series of Landsat multi-spectral and thermal *** study used the maximum likelihood algorithm for image classification and other methods like the correlation analysis and hotspot analysis(Getis–Ord Gi^(*) method)to examine the impact of LULC changes on urban thermal *** study noticed that the area percentage of built-up land increased rapidly from 21.91%to 45.63%during 1991–2021,with a maximum positive change in built-up land and a maximum negative change in sparse *** mean temperature significantly increased during the study period(1991–2021),from 16.31℃to 22.48℃in winter,29.18℃to 34.61℃in summer,and 19.18℃to 27.11℃in *** result showed that impervious surfaces contribute to higher LST,whereas vegetation helps decrease *** ecological status has been found in built-up land,and excellent ecological status has been found in vegetation and water *** hot spot and cold spot areas shifted their locations every decade due to random LULC *** after New Town Kolkata became a smart city,high LST has been ***,this study indicated that urbanization and changes in LULC patterns can influence the urban thermal environment,and appropriate planning is needed to reduce *** study can help policy-makers create sustainable smart cities.

关键词： Urbanization Land use/land cover (LULC)changes Land surface temperature Urban heat island Hotspot analysis Smart city

temperature Trends and Accumulation of Chill Hours, Chill Units, and Chill Portions in South Carolina

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Atmospheric and Climate Sciences 2024年第2期14卷 173-190页

作者： José O. Payero Edisto Research and Education Center Clemson University Blackville SC USA Department of Agricultural Sciences Clemson University Clemson SC USA

There is considerable concern about the potential impact of climate change on agriculture, such as the accumulation of chilling hours needed to break the dormancy of many perennial plants, like fruit trees. Therefore, this study aimed to determine if there had been a significant change in air temperatures and chill hours, chill units, and chill portion accumulation in South Carolina over the last two decades. Two decades of daily maximum (Tmax) and minimum (Tmin) air temperature records were obtained from weather stations in thirty-one counties in South Carolina. Hourly temperature data, reconstructed from the daily data, were used to calculate the daily and annual chill hours, chill units, and chill portions accumulation using four different chill models for each location and year. The chill models included the T(t) °C model, the 0°C °C model, the Utah model, and the Dynamic model. For each county, regression analyses were conducted to evaluate the historical trends. Despite year-to-year variability, the tendency was a statistically significant (α = 0.05) increase in air temperature, averaging 0.089°C per year for 20 out of 31 counties in South Carolina. The other 11 counties had no significant change in temperature. The average temperature increase in the 31 counties was 0.072°C per year. The temperature increase resulted in a decrease in annual chill accumulation during the fall to spring, averaging 17.7 chill hours, 8.6 chill hours, 17.0 chill units, and 0.40 chill portions per year calculated with the T(t) °C, 0°C °C, Utah, and Dynamic models, respectively. However, whether this decrease in chill values was statistically significant or not depended on the chill model used. This study did not investigate the cause of the observed historical trends in temperature and chill accumulation. Still, if the trends continue, they could significantly impact the future of the temperate fruit tree industry in the state.

关键词： Chill Hours Chill Units Chill Portions temperature Fruit Trees Climate Change Dormancy

Impacts of Climate Change on Seawater temperature and Total Dissolved Solids: Challenges and Sustainable Solutions for Reverse Osmosis Desalination in the Arabian Gulf Region

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Computational Water, Energy, and Environmental Engineering 2024年第1期13卷 86-93页

作者： Ahmed Al Kubaish Jamal Salama Water Quality Section Saline Water Conversion Corporation Al-Khobar Saudi Arabia

This article examines the influence of seawater temperature and total dissolved solids (TDS) on reverse osmosis (RO) desalination in the Arabian Gulf region, with a focus on the impact of climate change. The study highlights the changes in seawater temperature and TDS levels over the years and discusses their effects on the efficiency and productivity of RO desalination plants. It emphasizes the importance of monitoring TDS levels and controlling seawater temperature to optimize water production. The article also suggests various solutions, including intensive pre-treatment, development of high-performance membranes, exploration of alternative water sources, and regulation of discharges into the Gulf, to ensure sustainable water supply in the face of rising TDS levels and seawater temperature. Further research and comprehensive monitoring are recommended to understand the implications of these findings and develop effective strategies for the management of marine resources in the Arabian Gulf.

关键词： Climate Change temperature Reverse Osmosis Seawater Total Dissolved Solids Desalination

Further Analysis of Machine Tool Dimensional Accuracy and Thermal Stability under Varying Floor temperature

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World Journal of Engineering and Technology 2024年第2期12卷 258-273页

作者： Joel Arumun Shadrack Abiola Department of Control Systems and Instrumentation University of Huddersfield Huddersfield UK

Machining is as old as humanity, and changes in temperature in both the machine’s internal and external environments can be of great concern as they affect the machine’s thermal stability and, thus, the machine’s dimensional accuracy. This paper is a continuation of our earlier work, which aimed to analyze the effect of the internal temperature of a machine tool as the machine is put into operation and vary the external temperature, the machine floor temperature. Some experiments are carried out under controlled conditions to study how machine tool components get heated up and how this heating up affects the machine’s accuracy due to thermally induced deviations. Additionally, another angle is added by varying the machine floor temperature. The parameters mentioned above are explored in line with the overall thermal stability of the machine tool and its dimensional accuracy. A Robodrill CNC machine tool is used. The CNC was first soaked with thermal energy by gradually raising the machine floor temperature to a certain level before putting the machine in operation. The machine was monitored, and analytical methods were deplored to evaluate thermal stability. Secondly, the machine was run idle for some time under raised floor temperature before it was put into operation. Data was also collected and analyzed. It is observed that machine thermal stability can be achieved in several ways depending on how the above parameters are joggled. This paper, in conclusion, reinforces the idea of machine tool warm-up process in conjunction with a carefully analyzed and established machine floor temperature variation for the approximation of the machine tool’s thermally stability to map the long-time behavior of the machine tool.

关键词： Dimensional Accuracy Machine Tool Machine Floor Thermal Stability temperature Thermal Deviation

Evaluation of Cold Resistance and Semi-lethal Low temperature(LT_(50))of Nine Pear Cultivars

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Asian Agricultural Research 2024年第6期16卷 45-47页

作者： Huan LIU Lijuan GAO Jintao XU Minghui JI Longfei LI Baofeng HAO Changli Institute of Pomology Hebei Academy of Agriculture and Forestry SciencesChangli 066600China

[Objectives]To evaluate the cold resistance and semi-lethal temperature of pear cultivars,and provide a theoretical basis for the regional extension and breeding of cold-resistant pear cultivars.[Methods]Nine pear cultivars were used to study the changes in relative conductivity and cell injury rate of pear branches under low temperature stress,and the semi-lethal temperature(LT_(50))of pear branches was analyzed by fitting Logistic equation.[Results]The relative conductivity and cell injury rate of pear branches took on the trend of slow increase,rapid increase,and slow increase the decrease of treatment *** LC_(50) of the nine pear cultivars were as follows:Nanguo pear-33.9℃,Wanyu-32.3℃,Red D Anjou-31.8℃,Jinfeng-31.3℃,Wujiuxiang-29.2℃,20 th Century Pear-29.1℃,Hanxiang-35.1℃,Yuluxiang-27.9℃ and Korla Fragrant Pear-29.2℃.[Conclusions]The semi-lethal temperature could reflect the cold resistance of pear trees,and Wanxiang had better cold *** evaluation of cold resistance and semi-lethal temperature of pear cultivars can provide theoretical basis for regional extension and breeding of cold-resistant pear cultivars.

关键词： Pear Cold resistance Semi-lethal temperature (LT_(50)) Low temperature