Increase In Ambient Temperature Research Articles

Experimental Investigation of Thermal Effect on the Frictional Characteristics of HCC Friction Clutch Material

Increasing temperature due to frictional heat from sliding between contacting surfaces leads to increased wear and friction. Therefore, the researchers continue investigations to find the most suitable friction materials with good mechanical and thermal properties for frictional facings of clutch performance under this condition. In this research paper, the behavior and performance of the friction material HCC was studied under different normal load conditions (125, 175, 225, and 275 N) and different working environment temperatures (300 K and 390 K), where the rotation speed was 300 rpm. The results of the coefficient of friction and friction forces variation under different working conditions were analyzed and discussed in detail. XTM 500 tribometer test rig was used to perform the required tests, and the samples were made of the HCC friction material. The obtained results proved that the ambient temperature of the friction system has a significant negative effect on both the coefficient of friction and the force of friction. So, when the friction system's ambient temperature increases, the magnitude of the friction coefficient will decrease, and, thus, the transmitted torque will reduce too.

Climate-adaptive resilience in district buildings and cross-regional energy sharing in Guangzhou-Shenzhen-Hong Kong Greater Bay Area

Climate change imposes challenges on Sustainable Develop Goals (SDGs) with uncertainty in the energy supply, energy consumption, climate-adaptive design and operation, renovation and retrofit on traditional energy systems. However, academic studies focus on district energy system sizing, operation and energy analysis under typical year, without considering future climate change due to the lack of updated meteorological database. In this study, models are developed to predict meteorological parameters in Greater Bay Area. Building physical models are developed in TRNSYS 18 platform with power-to-cooling/heating conversions and thermal/electrical energy storages to quantitatively analyse the impact of climate change on cooling/heating/electric loads, rated capacity resizing and onsite renewable energy supply. Considering the differences in building intensity, types, available spatiotemporal spaces in the Greater Bay Area, spatiotemporal energy sharing networks with E-mobility in cross-boundary Guangdong-Hong Kong-Macao are developed for cross-regional renewable self-consumption and stablising local microgrid power/voltage. Results indicate that, both solar radiation and ambient temperature increase under the future climate change, while building services systems designed in the typical year fail to cover cooling demands due to future climate change. Immediate response and sufficient reaction to climate change with climate-adaptive design require gradual increase on rated capacities of chillers, together with the increase in total electricity consumptions (i.e., increased by 34.3%, 29.9%, 14.2% and 20.5% for residential buildings, hotel, office, and commercial buildings from typical year to the year 2100). Technical strategies for future climate change adaption include complementary solar-wind energy integration, E-mobility based cross-regional energy sharing, renewable-to-EV charging and EV discharging for grid support under the Vehicle-to-Grid (V2G) mode. The V2G mode is economically beneficial with overwhelming superiority in grid import cost saving than battery degradation cost. This study can contribute to future climate change prediction, climate-adaptive designs, operations and controls, and energy resilience improvement.

Investigation on the bearing capacity evolution of building pile foundation during permafrost degradation

The warming and melting of permafrost due to climate warming pose a considerable threat to the integrity of the Pan Arctic building, thus jeopardizing sustainable development. The increase in ambient temperature in permafrost areas will cause deterioration in the bearing capacity of building pile foundations. Considering the continuous deepening of the active layer (za), the present paper used small-scale physical modeling to investigate the potential variation of bearing capacity and load transfer mechanism of pile foundations under the scenario of continuous degradation of permafrost. The ultimate bearing capacity of a single pile and the undrained shear strength of the ground under different za are estimated by cone penetration tests. In the static load test of single piles, the axial load-settlement, axial force of pile shaft, and earth pressure at the pile tip are measured. The results show that the rise in ground temperature and the deepening of the za shorten the elastic and elastic-plastic stages of the load-displacement curve, resulting in a gradual decline in the bearing capacity of a single pile. The pile-soil interface temperature is always higher than the adjacent ground temperature at the same depth. Adfreezing force of the pile-soil interface decreases due to the increase in ground temperature and water content. With the deepening of za, the peak point of the shaft resistance decreases from −30 cm to −60 cm under the ultimate state. Meanwhile, with more axial load transfer along the pile shaft to the pile tip, the share ratio of pile tip resistance to ultimate stress gradually increases. In addition, the temperature rise of frozen soil at the pile tip accelerates the settling rate of the pile, which eventually causes the pile foundation failure.

Bottom-hole pressure inversion method for nature gas wells based on blowout combustion flame shape parameters

In response to the challenges associated with the difficulty of obtaining critical well control parameters, particularly bottom-hole pressure, during a well blowout fire, a comprehensive computational fluid dynamics (CFD) model for analyzing well blowout fires is developed based on fluid mechanics and combustion theory, considering factors such as gas composition, pressure, wellhead diameter, wind speed, and temperature, and is validated by published experiment date. Then, a CFD simulation database is constructed by conducting a sensitivity analysis of the flame height to investigate the correlations among flow field, operating conditions and flame parameters. Subsequently, an approach incorporates an AutoEncoder (AE) to reduce the dimensionality of the highly correlated raw data, and a Bayesian Optimization-based Radial Basis Function Network (BO-RBFN) to explore the inherent patterns within the established CFD dataset and then establishes a fuzzy relation between immeasurable wellhead flow velocity and well blowout fires operating parameters, achieving an accurate prediction of wellhead flow velocity. Furthermore, utilizing the wellhead gas velocity and the calculated wellhead pressure as the initial conditions, the bottom hole pressure during blowout fire is inversed based on wellbore temperature and pressure model. As a result of this study, a model integrating numerical model, databases, intelligent algorithms is developed for determining bottom-hole pressure in the presence of a blowout fire. And the proposed deep learning-based approach demonstrated exceptional accuracy in predicting wellhead gas flow velocity, with an average absolute difference of less than 2% between validation set and test set. In addition, as the ambient temperature, wellhead pressure, and wellhead diameter increase, the height of the blowout flame increases. In contrast, as the gas temperature and wind speed increase, the height of the blowout flame gradually decreases. Notably, only marginal changes in flame height resulted from alterations in gas composition. This study can quantitatively reveal the cause of well blowout and evaluate the severity of well blowout, and have practical significance in guiding the design and execution of subsequent rescue operations for uncontrolled blowouts fires.

Employing the spray system to alleviate the thermal action of air-conditioning in summer

Widespread adoption of air-conditioning significantly enhances indoor thermal comfort in summer, but the heat dissipation from these outdoor units contributes to an increase in ambient air temperature, exacerbating urban heat island effects. Consequently, as outdoor thermal conditions worsen, the energy consumption associated with air-conditioning is likely to escalate. The spray system becomes a suitable choice due to the obvious advantage of heat absorption through the droplet evaporation. To assess the effectiveness of the spray system in reducing heat release, a comparative study was conducted between two identical buildings with the same air-conditioning system, but only one of which incorporated the spray system. Three installed locations are considered with the spray location in inlet (Case 1), outlet (Case 2) and both inlet & outlet (Case 3) of outdoor units. The results demonstrated the average temperatures of air outlet were reduced by 4.0 °C, 6.3 °C, and 7.9 °C for Cases 1–3, respectively, accompanied by a reduction in energy consumption of the air-conditioning system by 18.8%, 13.9%, and 37.3% respectively. The most significant benefits were observed when the spray location was installed in both outdoor unit inlet and outlet (Case 3). The spray system established a virtuous cycle in heat dissipation improvement, evaporation enhancement, and air temperature reduction.

Application of the thermoelectric cooling system in making a cooling belt: A case of heat stress control measure device.

Climate change and global warming are emerging as new challenges worldwide. The World Meteorological Organization has reported that the temperature is expected to rise by an average of 1.2°C between 2021-2025. This increase in temperature will expose more and more workers to extreme heat. This study aimed to explore the possibility of using thermoelectric coolers for cooling the water circulation circuit of a cooling belt, which can be used for extended periods in high-temperature environments. A cooling belt was designed using thermoelectric coolers (TEC) and two blowers. The TECs were equipped with heat sinks and heat exchange block made of aluminum at hot and cold sides to exchange heat effectively. The experiment was conducted under actual environmental temperature conditions during three different time periods, with mean temperatures of 31, 48, and 41°C. The mean temperature of the belt section was recorded as 20.73, 24.52, and 21.38°C, respectively. The maximum average difference between the inlet air temperature and the inside cooling belt temperature was 40.45°C. The experiment revealed that the cooling performance of the designed prototype remained within an acceptable range (18°C) despite the increase in ambient temperature. Moreover, the cooling system can be utilized in high-heat environments to reduce thermal stress.

Contrasting responses to microhabitat and temperature determine breeding habitat differentiation between two Viola‐feeding butterflies

Abstract Since widespread monitoring began in 1976 in the UK, habitat‐specialist butterfly populations have declined dramatically. The main driver is habitat degradation, caused primarily by land‐use change, perhaps interacting with changes in vegetation phenology. Here, we focus on two declining species: Boloria selene (Dennis & Schiffermüller) and Boloria euphrosyne L., Lepidoptera: Nymphalidae. We hypothesise that these species differ in their preferred breeding habitat, and this is driven by differences in their temperature preferences, mediated by vegetation cover. We use mark‐release‐recapture techniques and oviposition observations to characterise and compare adult distribution, habitat use and oviposition site preferences of the two species. Egg‐laying females of both species are shown to occur in areas with relatively high abundance of the larval food plants, Viola spp. (violets), principally V. riviniana, and they oviposit where Viola spp. abundance is locally high. However, in contrast to B. selene, ovipositing B. euphrosyne tends to occur in areas with relatively short and sparse cover of vegetation. B. euphrosyne oviposit in sites with a relatively high plant surface temperature irrespective of ambient temperatures, in contrast with B. selene in which the temperature of oviposition sites increases as ambient temperature increases. These differential temperature strategies likely underlie differences in breeding habitat preference. Microclimatic cooling caused by increased vegetation growth in spring may be one reason B. euphrosyne is declining in the UK, while both B. euphrosyne and B. selene may be affected by declining Viola spp. availability. Our data provide further evidence that drivers of butterfly declines can be multi‐factorial, and paradoxically, that thermophilic species do not necessarily benefit from climate warming if responses of other species result in cooling of their habitats.

Air Temperature Modeling Based on Land Surface Factors by the Cubist Method (Case Study of Hamoun International Wetland)

The drying up of Hamoun International Wetland (HIW) and the loss of vegetation in this area have led to an increase in ambient temperature. This research examines the changes in the surface of HIW and its role in air temperature (Tair) using data on land surface temperature (LST), vegetation, wind speed, and relative humidity. The Cubist regression model (CRM) is used to simulate the effects of land surface factors (LSFs) on Tair. Four microsites with different plant cover percentages were selected for this purpose. After data collection, 75% of the data were used for modeling and 25% of the data were used for model testing. The results showed that CRM has adequate performance for estimating Tair. The assessment of the relationship between land surface temperature (LST) and Tair at 2 meter height showed that there was a high correlation coefficient between 0.86 and 0.91 in the different microsites. The results of using CRM for estimating Tair showed that this model can estimate air temperature from independent parameters of LST, wind speed, vegetation percentage, and relative humidity with a correlation coefficient of 0.98. In this model, the LST, relative humidity, and vegetation percentage were entered with values of 100%, 93%, and 83% respectively. Wind speed was not included in the model because the measurements were constant and less than 4 m/s throughout the period (no changes).

Effect of controlled solvent evaporation on the electroactive phase content of P (VDF-HFP) films

Poly (vinylidene fluoride)-based dielectric materials have attracted much attention in the field of high power density electric energy storage due to their ferroelectric properties, high dielectric breakdown strength and superior processability. However, it is a key challenge how to obtaining high content electroactive phases with ferroelectric and piezoelectric properties in PVDF. Up till now, researchers have prepared PVDF films with high content of electroactive phase via irradiation with high-energy electron-beam or γ-ray radiations and pressing-and-folding process. In this paper, P(VDF-HFP) films were prepared by controlled solvent evaporation method at different ambient temperature. The results showed that the morphologiy of the film showed insignificant changes with the increase of ambient temperature. Total contents of β and γ phases were nearly 100 % in the PVDF films prepared at ambient temperature below 110 °C. The microcrystals in P(VDF-HFP) was more and more perfect with the increase of the ambient temperature under the condition of controlled solvent evaporation. The films prepared at 70 °C showed a dielectric constant of 12.76 under the test condition of 100 Hz with the remnant polarization of 0.54 μC/cm2. All of these results demonstrated that the formation of the electroactive phase of P(VDF-HFP) thin films was related to the evaporation process and evaporate rate of the solvent.

Body temperature and thermoregulatory behaviour in the Endangered African Penguin Spheniscus demersus

Summary Heat stress from high temperatures has been recognised as a threat to several bird species and one that is likely to increase in severity and frequency as a result of global environmental change. Many seabirds are particularly vulnerable as their adaptations to forage in cold water can make it hard for them to resist heat gain while on land. The African Penguin Spheniscus demersus forages in cool water (10–20°C) but breeds and moults on land where temperatures can exceed 30°C. Little is known about its thermal physiology and when heat stress will occur. Here, we provide the first account of changes in body temperature and behaviour in African Penguins in response to an experimental increase in ambient temperature from 20°C to 35°C. Surprisingly, the highest body temperature observed (39.2°C) was recorded at the start of the study. Presumably, this response in body temperature was due to the stress of transport and handling. Penguins returned to normal body temperature (37.3°C) after 3.5 hours and maintained normothermia for roughly an hour. We then observed the onset of heat storage at an ambient temperature of 29°C, whereafter body temperature increased steadily at a rate of ca.0.2°C per 1°C increase in ambient temperature. Panting commenced at an ambient temperature of 31.4°C, when body temperature was 37.8°C. In addition to panting, penguins changed their posture to facilitate heat dissipation by standing, raising their heads, and extending their flippers. Our results corroborate field observations and support the argument that African Penguins are highly vulnerable to heat stress in the near future as extreme heat events become more severe and frequent due to climate change. Our results also confirm that penguins are sensitive to handling, which elicits a hyperthermic response. Given the general sensitivity of penguins to disturbance, from a conservation perspective, we advise that cautionary measures be implemented at colonies during critical life-history stages.

Temperature dependence of MXenes plasmons induced hot carrier generation and transport

Unlike conventional optoelectronic devices, plasmon-driven optoelectronic devices can efficiently realize energy conversion and regulate the energy distribution of hot carriers through high-energy, non-equilibrium “hot” electron-hole pairs (hot carriers) generated by surface plasmon non-radiative decay, thereby presenting new opportunities for realizing hot carrier optoelectronic devices. As the basis for the practical application of plasmon optoelectronic devices, searching for plasmon metal materials with exceptional performance has always been an important topic in the field of hot carrier optoelectronic devices. Currently, MXenes can be synthesized on a large scale and has excellent photoelectric properties, so it can be used to build a variety of hot carrier photodetectors with unique structures and functions. Unlike the fixed surface ends of two-dimensional materials such as graphene, MoS<sub>2</sub> and borophene, MXenes has an abundance of surface functional groups. However, the increase of ambient temperature will accelerate the oxidation modification of surface functional groups, thus affecting the life and performance stability of optoelectronic devices. In view of the inherent limitations of experimental research on dynamic characteristics of hot carriers at continuous temperatures, we study the temperature effects on the electronic state distributions and scattering effects by using the theory of multi-body perturbation and quantum mechanics. Particularly, we introduce temperature effect into interband electron transition and phonon-assisted electron transition process to obtain temperature dependent dielectric function. From the perspective of non-radiative decay of surface plasmon, we quantify the hot carrier generation efficiency, energy distribution and transport characteristics by first principles calculations, in order to systematically study the ambient temperature dependence of plasmon-induced hot carriers in MXenes. The results show that the interband transition and the phonon-assisted electron transition in MXenes together efficiently produce high-energy hot hole-dominated carriers with a long lifetime and transport distance, which is comparable to borophene. The increase of ambient temperature significantly improves the hot carrier generation efficiency in the infrared range. Meanwhile, the physical mechanism of hot carrier generation in visible light is almost unaffected by the increase of ambient temperature, and the generated hot holes show excellent ambient temperature stability. In addition, the lifetime and transport distance of hot carriers decrease with ambient temperature increasing, which is mainly due to the enhanced scattering of electrons and optical phonons. The research results will provide theoretical and data support for quantitatively evaluating the ambient temperature stability of MXenes plasmon optoelectronic devices in practical environment.

Multi-stimuli responsive photonic hydrogel based on a novel photonic crystal template containing gold nanorods.

Multi-stimuli responsive photonic hydrogels (MRPHs) fabricated by doping nanoparticles into hydrogels show promising potential value in the fields of visual detection and drug delivery. However, complicated surface chemical modification is selected to improve the compatibility between nanoparticles and a pre-gel solution of hydrogel. Herein, we developed a simple and convenient vertical deposition method to prepare a novel photonic crystal (PC) template containing gold nanorods (Au NRs) (Au NRs/PC template), which could respond to near-infrared (NIR) light due to the conversion capability of Au NRs from NIR light to heat. Additionally, carboxyl groups on the surface of polystyrene (PS) colloids endowed the Au NRs/PC template with pH-stimulus responsiveness. Based on the Au NRs/PC template, MRPH film was fabricated by infiltrating the pre-gel solution of poly(N-isopropylacrylamide) (PNIPAM) hydrogel into the gap of a 'sandwich' structure through capillary forces and then polymerizing at 25 °C for 24 h. The obtained MRPH film could respond to NIR light, pH and temperature. Under the irradiation of NIR light, only the irradiated position lost structural color while the film volume had no distinct change. With the increase of ambient temperature, the whole MRPH film completely lost structural color and shrank significantly, which was greatly different from the phenomenon irradiated by NIR light. Besides, the structural color of the MRPH film exhibited a red shift from green to orange-red as the pH increased. Overall, both the Au NRs/PC template and the MRPH film may have potential applications in visual detection, due to their multi-stimuli responsiveness.

РЕЗУЛЬТАТЫ НАТУРНОГО ЭКСПЕРИМЕНТА ПО УСТАНОВЛЕНИЮ ЗАВИСИМОСТИ ПОТРЕБЛЯЕМОЙ МОЩНОСТИ ЭЛЕКТРОМОБИЛЕМ ОТ ВНЕШНИХ ФАКТОРОВ

The article is devoted to the problems of operation of cars with an electric power plant in country mode. In the course of the work, a full-scale experiment was planned and conducted to establish the quantitative dependence of changes in the power consumption of an electric vehicle on external factors: speed of movement and ambient temperature. It is established that an increase in the speed from 70 to 110 km / h will lead to an increase in power consumption by more than 4 times. At the same time, the ambient air temperature has less influence and an increase in ambient air temperature by 15° C, the power consumption during operation increases by 17,6%.

Effects of magnetism on porous rectangular fins with convection and radiation

A fin is an extended surface used to enhance the surface area of a heat transfer surface between a hot source and the outside environment. To maximise the rate of heat transportation, the exterior surface of heated equipment is equipped with fins of various geometries. Heat is exchanged using fins in radiators, refrigeration systems, superheaters, combustion engines, electrical equipment, electric transformers, space vehicles, and aircraft engines. Reflecting these applications, we analyse the effect of a magnetic field on the thermal properties of radiating porous rectangular fins. The proposed model is numerically analysed using the shooting method under the influence of radiation and convection, then compared with the DTM solution and both the solution found closer to each other. The effect of various dimensionless parameters on temperature transmission in magnetized rectangular-shaped porous fins is revealed using numerical results. It is revealed that, when the Raleigh, Hartmann, Peclet numbers, convective and radiative parameters increase, the fin?s thermal profile decreases, whereas the thermal profile increases with an increase in surface temperature, porosity, and ambient temperature. It is observed that the magnetic effect increases the heat transfer rate from porous rectangular fin surfaces. Accordingly, efficiency increases as Hartmann number, Raleigh number, and radiative parameter rise. Increasing Peclet number, surface temperature, and ambient temperature leads to a reduction in efficiency.

Laser flowmetry of microcirculation of the finger depending on the external temperature and the limb position

Introduction. The use of laser Doppler flowmetry (LDF) makes it possible to assess the condition and disorders of blood microcirculation, improving the quality of diagnosis of various cardiovascular diseases. Additional functional tests with laser flowmetric measurements are used to assess the state of the mechanisms that regulate the tissue blood flow. Objective. To identify patterns of blood flow changes in the microcirculatory bed when combining a postural test and a change in air temperature. Materials and methods. The study was conducted on a group of 20 subjects, which included an equal number of girls and boys aged 21–23 years, who were considered healthy and did not have cardiovascular diseases. The experiment was carried out in two stages: first in a room with an air temperature of 201 °C, then at 301 °C. To assess the difference in data between arm positions within the same study phase at the same temperature, the Student’s t-test was used to compare quantitative variables in two dependent samples. The Wilcoxon test was used to assess statistical differences in data for the same hand position but at different air temperatures. Changes were considered statistically significant at p<0.05. The subjects were measured the microcirculation of peripheral blood vessels on the phalanx of the finger in three positions relative to the level of the heart using a portable laser Doppler flowmeter LAZMA PF (Russia). Results. It is shown that an increase in ambient temperature leads to an increase in the difference in microcirculation of peripheral vessels when the arm position changes relative to the level of the heart. When a person is in a room with a temperature of 301 °C, dilation of blood vessels and changes in their tone occur, which explains the increase in microcirculation values in relative perfusion units. Conclusions. The results of the study showed an increase in statistically significant differences according to the Student’s t-test between the different hand positions with increasing room temperature (p<0.0001). In a comparative sample between the first stage (at an air temperature of 20±1 °C) and the second stage of the study (at an air temperature of 30±1 °C), statistically significant results (p<0.001) were obtained according to the Wilcoxon test for the hand position at the heart level and the raised arm.

Tissue Lipid Profiles of Rainbow Trout, Oncorhynchus mykiss, Cultivated under Environmental Variables on a Diet Supplemented with Dihydroquercetin and Arabinogalactan.

Reared rainbow trout are vulnerable to environmental stressors, in particular seasonal water warming, which affects fish welfare and growth and induces a temperature response, which involves modifications in tissue lipid profiles. Dietary supplements of plant origin, including the studied mix of a flavonoid, dihydroquercetin and a polysaccharide, arabinogalactan (25 and 50 mg per 1 kg of feed, respectively), extracted from larch wood waste, were shown to facilitate stress tolerance in fish and also to be beneficial for the safety of natural ecosystems and the sustainability of aquaculture production. This four-month feeding trial aimed to determine the effects of the supplement on liver and muscle lipid accumulation and the composition in rainbow trout reared under environmental variables. During periods of environmental optimum for trout, a consistent increase in energy lipid stores, particularly triacylglycerols (2.18 vs. 1.49-fold over a growing season), and an overall increase in lipid saturation due to lower levels of PUFAs, such as eicosapentaenoic (20:5n-3), docosahexaenoic (22:6n-3) and arachidonic (20:4n-6) acids, were observed in both control and supplement-fed fish, respectively. However, in fish stressed by an increase in ambient temperature, dietary supplementation with dihydroquercetin and arabinogalactan reduced mortality (3.65 in control vs. 2.88% in supplement-fed fish, p < 0.05) and alleviated the high-temperature-induced inhibition of lipid accumulation. It also stabilised the membrane phospholipid ratio and moderated the fatty acid composition of fish muscle and liver, resulting in higher levels of n-3 PUFAs and their precursors. Thus, the natural compounds tested are beneficial in accelerating fish tolerance to environmental stressors, reducing mortality and thermal response, and moderately improving fillet quality attributes by increasing the protein/lipid ratio and the abundance of fatty acids essential for human nutrition.

Study on spray characteristics of biodiesel alternative fuels for in-cylinder environment of diesel engine

This paper presents an experimental study of spray characterization of MD-NH (a blend of methyl decanoate and n-heptane in a molar ratio of 1:1 to characterize biodiesel) in an in-cylinder environment of diesel engines to provide a reference for the experimental study of engines in advanced combustion mode. Based on the Peng-Robinson state equation, the thermodynamic model of real fluid was established, and the influence law of ambient temperature and pressure on the diffusion characteristics of fuel flow was analyzed. Based on the constant volume combustion bomb experiments, the variations of spray penetration distance, spray cone angle, spray projection area, spray air entrainment mass, and spray fragmentation forms in different critical environment conditions were studied. The results show that the transport properties of the fuel change abruptly within the critical point neighborhood of the fuel. As the ambient temperature increases, near the critical temperature, the thermal conductivity of biodiesel decreases and then increases; density and kinematic viscosity decrease at an accelerated rate; and surface tension increases to a maximum and then disappears sharply. The diffusion coefficient decreases sharply when the ambient pressure reaches the critical pressure. The spray characteristics of biodiesel in sub/supercritical conditions were different. Compared with the subcritical environment, the biodiesel spray penetration distance decreases, the spray cone angle increases, the spray projection area decreases, and the air entrainment mass increases in the supercritical atmosphere, which induces a gas-liquid interface mixing layer and promotes the mixing of biodiesel with the atmosphere gas. The experimental data in this paper fill the gap in the study of biodiesel spray characteristics in supercritical environments and provide a basis for high-fidelity numerical simulation of the spray model.

Changes in Intergranular Air Properties and Chemical Parameters of Short-term Stored Bulk Shelled Corn with Slightly High Moisture Content

Objective: This study is to determine the main parameters influencing the storage of shelled corn with slightly high moisture content (MC) so that its quality can be maintained. Methods: The intergranular air properties and chemical changes was determined in 4,169 tonnes of shelled corn bulk with an average MC of 15.3% and a height of 5m, which was stored for 90 days in a large warehouse in Shandong Province, China, from winter to early spring. The intergranular air property parameters were calculated with self-compiled software. Results: Fans were used to achieve temperature-equalizing aeration at a low rate (5.87m3/h/t) after warehousing, which decreased the bulk temperature from 6.8 to 4.7℃. Afterwards, with the increase in ambient temperature, the surface-layer grain temperature increased drastically, while that of the bottom layer increased slowly and those of the middle layers increased even more slowly. The minimum and mean cumulative dry-bulb, wet-bulb and dew-point temperatures (DPT) increased in the order of middle layer˂ bottom layer˂ surface layer. Free fatty acid content, kernel breakage percentage, water adsorption rate, gelatinization enthalpy, peak enthalpy, and fatty acid profiles (C16:0, C18:0, C18:3n3, C20:0 and C20:1) were significantly related to the cumulative intergranular air properties of grain bulk. Conclusion: The above physio-chemical parameters were significantly influenced by the minimum and mean cumulative values of relative humidity, Humidity ratio and DPT in the bulk, and can be used to evaluate the quality of shelled corn with slightly high MC during short-term storage.

Neutron Nanomediators for Non-Invasive Temperature Mapping of Fuel Cells

Polymer electrolyte fuel cells (PEFCs) have gained significant attention in the past century for their ability to convert hydrogen chemical energy into electrical energy. However, the technology still requires refinement due to losses in polarization, ohmic resistance, and mass transport that result in heat generation, negatively affecting the device water management and durability. To better understand these processes, researchers initiate studies to improve knowledge of the temperature at the cell structure core. However, current methods using micro-thermocouples [1] are highly invasive, impeding cell operation and limiting data accuracy.The project aims to overcome the latter problem using ferromagnetic nanoparticles for non-invasive temperature mapping on these devices. A key part of this novel method is the application of Neutron Imaging through a polarized beam [2], which allows to detection of the temperature distribution on the surrounding nanosensors. The dispersed ferromagnetic nanomediators, in these conditions, depolarize the incoming neutron beam due to the random magnetic field produced by the nanoparticles themselves. Furthermore, as the temperature rises toward the Curie temperature (Tc), the nanosensors tend to lose their magnetic preferential orientation, influencing the neutron beam polarization gradually less as the ambient temperature increases.This project includes identifying a suitable material, synthesizing nanoparticles through solution techniques [3], and performing physical and magnetic ex-situ characterizations. By dispersing them in Polytetrafluoroethylene micro-powders, nickel, iron, and Nd2Fe14B alloys were initially studied at different concentrations, grain sizes, and magnetic environments, showing promising signal detection (η) and absolute thermal variation (Δη) results.

Investigation of green roofs effects on reducing of the urban heat islands formation (The case of a municipal district of Tehran City, Iran)

Urban heat islands (UHI) are of the most common urban phenomena according to which some urban regions, especially downtowns, are hotter than the surrounding by some degrees. Urban development and its relationship with UHIs are important topics that should be first understood and then controlled by devising relevant plans for the trend of urban development. Municipal District 6 (MD-6) is an oldest and the most populous areas of Tehran city in Tehran province-Iran, which also has a high building density. In order to reduce the calculation error, this area is divided into 23 sections. And modeling in each section is done by comparing closely related sections separately. The results of this study can be generalized to all same parts of the world. Initially, earth surface temperature is estimated using Landsat 8 satellite data. Then, the vegetation area of each section is calculated using Normalized Difference Vegetation Index (NDVI). And in the next step, by establishing a relationship between the obtained data, the rate of reduction of UHI is determined by adding a certain area of vegetation. Also, a map was prepared that showing the buildings on UHI, thus measuring the area of roofs with the ability to add vegetation. Finally, the modeling is based on this information. Results show with the addition of vegetation to the roofs of buildings, an average of% 38.58 of the area and 0.68°C of the intensity of the UHI was reduced in this area. Modeling gave different results for other sections depending on their location and the area of buildings inside heat islands that can be used for green roof development. When the material of urban surface changes and water and humidity penetration increases due to the replacement of these surfaces with plants, more time will be required for the increase in ambient temperature by plants versus impermeable surfaces like asphalt and concrete. Therefore temperature rise in plants needs more time than in impermeable surfaces.