Outdoor Thermal Environments of Main Types of Urban Areas during Summer: A Field Study in Wuhan, China

Under the influence of the urban heat island effect, the thermal environments of urban built-up areas are poor, leading to the loss of urban vitality and the extreme deterioration of thermal comfort. In this paper, the outdoor thermal environment in Wuhan’s main urban area is studied via the use of field measurements. From June to August in the years 2015 to 2017, 20 measurement points were selected for monitoring from 08:00 to 19:00 h, which were located in spaces such as residential areas, parklands, commercial streets, and college/university campuses. The measurements for the same types of land and different types of land use are analyzed. A comprehensive thermal environment index is used to quantitatively evaluate the overall situations of thermal environments. The results showed that the cooling effect of vegetation shading was stronger than the effect of water evaporation and the maximum temperature difference between the two cooling methods reached 6.1 °C. The cooling effect of the canopy shading of tall trees was stronger than the effect of grassland transpiration and the maximum temperature difference was 2.8 °C. The streets with higher aspect ratios might improve the ventilation, but the wind speeds remained low, which did not provide a strong cooling effect. This study helps urban planners understand the thermal environment of Wuhan or similar cities with hot summer and diversified urban areas, and puts forward suggestions to reduce the heat island effect from the aspect of building layout, green coverage, shading mode, and street aspect ratio, so as to establish sustainable cities that are climate adaptable and environmentally friendly.

Characterizing the Effect of Processing Parameters on Temperature Distribution of 7075 Aluminum Alloy Slurry Prepared by Enthalpy Control Process

There is a strong demand for high-strength aluminum alloys such as 7075 aluminum alloy to be applied for rheocasting industry. The overriding challenge for the application of 7075 alloy is that its solid fraction is very sensitive to the variation of temperature in the range of 40% ~ 50% solid fraction, which inevitably narrows down the processing window of slurry preparation for rheocasting process. Therefore, in this work, a novel method to prepare semi-solid slurry of the 7075 alloy, so called Enthalpy Control Process (ECP), has been developed to grapple with this issue. In the method, a medium-frequency electromagnetic field was applied on the outside of slurry preparation crucible to reduce the temperature difference throughout the slurry. The effect of processing parameters, including heating power, heating time, the initial temperature of crucible and melt weight, on the temperature field of the semi-solid slurry was investigated. The results exhibited that although the all the processing parameters had a great influence on the average temperature of the slurry, heating time was the main factor affecting the maximum temperature difference of the slurry. The optimum processing parameters during ECP were found to be heating power of 7.5 KW, the initial temperature of crucible of 30 °C ~ 200 °C and melt weight of 2 kg.

The Effect of Different Cover and Flooring Materials on Climatic Comfort in Landscape Design

In this study, it is aimed to understand the effects of structural and vegetative elements that can be used in landscape designs on the temperature factor, which will greatly affect the climatic comfort, by using artificial neural networks. In this context, measurements were carried out in the morning (08:00-09:00), noon (13:00-14:00) and evening (17:00-18:00) of a total of 100 days, 50 days in each of the winter and summer seasons, at 7 randomly selected points in the Akdeniz University Campus. In these measurements, the temperature difference values of 11 cover elements on 7 different floor covering types were measured, and the ambient air temperature, humidity and wind values were also determined. The temperature differences between the areas where the flooring elements are exposed to direct sun and the shadow effect of different plant and cover elements were determined using an infrared laser thermometer. These values were processed with Neural Designer software and possible temperature difference prediction values were created for 57.750 different alternatives with the help of artificial neural network model from 837 sets of data. Evaluation shows that the maximum temperature difference is 15.6°C at noon in the summer months in the red tartan flooring material and Callistemon viminalis cover material. While the artificial neural network model predicts that there will be a high 2-3° C temperature difference for the alternatives, it has made predictions for temperature differences between 0-10°C in winter and 0-16°C in summer months. Although the temperature differences that will occur in the noon hours are distributed over a wide range of values, it seems that the morning and evening forecasts are concentrated between 0-7°C values. Also, it has been determined that the wind and humidity in the environment are more important factors than the ambient temperature in terms of temperature differences.

Energy exchanges between ocean and atmosphere in relation to southwest monsoon performance over India

Energy fluxes over Indian seas have been computed for pre-monsoon and monsoon months of the years 1987 and 1988 using bulk aerodynamic equations with exchange coefficients which vary with wind speed and stability, The years 1987 and 1988 have bee~ chosen due to the constrasting nature of the performances of Indian summer monsoon during these years. Besides energy fluxes several other oceanographic parameters, viz., SST, sea-air temperature difference, 'Bowen ratio'and 'rate of wind work' have been computed and examined. The distributions of these parameters over Indian seas during 1987 and 1988 reveal several constrasting features. Some of these features provide predictive indications of monsoon performance.

Long-ranged order in a thermally driven system with temperature dependent interactions

Aggregation of macro-molecules under external drive is far from understood. An important driving situation is achieved by temperature difference. The inter-particle interaction in metallic nanoparticles with ligand capping is reported...

NOCTURNAL SURFACE INVERSIONS IN CENTRAL EASTERN INDIA

Monitoring of nocturnal su rface inversions in the vicinit y of Steel Authority of Ind ia lid. Steelplants at Bhila i. Bokaro. Durgapur and Rourk-cia in central eas tern Ind ia. for 40 niahu in January. February andMarch 1990. indi cated that surface inversions developed every night when weathe r conditions were favourable (clea rskies and light winds) , Th e ceiling heiaht of surface inversions eenerally increased as the niah t progressed. withrouahly two-th irds hiefler th an 100 m and a maximum record ed heigh t of 520 m. Th e maximum recorded surfaceinversio n strt"ngth (temperature difference between th e surface and the ceilingjwas 8.6C· at Dura:apur.1 .4C· at Bhilaiand aroun d 5-SC· at both Bokam and Rourkela. A reaso nable estimate of the .srrongest surface inversion would beJOC· to 12C· in the lOwnl 250 m of th e atmosphere.The proportion of surface invers ions greater than 4C· was 80%atDurgapur. .s5llb at 8hilal4.s% at Bokaro an d If.'" at Rourkela.These differences between loca tion!'wee- caused la l'iel yby varying weathe r conditions during the monit oring period.

PERPINDAHAN PANAS HYBRID PHOTOVOLTAIC DAN THERMOELEKTRIC GENERATOR DENGAN HOT MIRROR

Heat transfer is the transfer of energy from one area to another due to the temperature difference between these areas. Wasted heat energy can be converted into electricity using (TEG) between the hot and cold sides. If the temperature difference is more significant, the efficiency may increase along with the operating temperature of the TEG-type material. So in this study, the author will calculate the heat transfer that occurs in Photovoltaic (PV), Thermoelectric Generator (TEG), and Hot Mirrors by utilizing thermal energy light produced from Muxindo LED bulbs with 10 Watt, 15 Watt, and 20 Watt power. The results of this study indicate that by using 10, 15, and 20 Watt LED bulbs for free convection heat transfer, the power generated from each point increases because it passes through several obstacles from objects that experience a decrease in temperature to PV and TEG, with the characteristics of the displacement. The movement of molecules from the medium importance follows convection heat at every point of transfer in the intermediate substance. The most significant power generated from radiant heat transfer is about 0.1873 Watt. It occurs on the surface of the fresnel lens using a 20 Watt LED bulb with the characteristic that the radiation propagates in a straight line and does not require an intermediate medium to transfer heat from one substance to another. The most significant conduction heat transfer power, 0.2453 Watt, occurs in Fresnel Lens using a 20 Watt LED bulb with heat transfer characteristics in solid objects.