Study on non-equilibrium solidification microstructure of Al-16Si alloy

The goal of the present work is to investigate the effects of target plate temperature on heat transfer features of representative active clearance control (ACC) geometries presenting 0.8 mm circular impingement holes arranged in a single row pattern. The jets generated by such holes cool a flat target surface, which is replicated by a metal plate in the experimental setup. A steady-state technique with controlled wall heat flux is used to measure averaged heat transfer values along the target plate. The target plate is composed by a series of insulated blocks to limit lateral conduction effects and also to assure a fine control of the supplied power. A full characterization of pipe, target plate and flow temperature is obtained using thermocouples and IR camera. Target plate temperature level ranges from 330 K to 570 K, while the manifold inlet temperature is kept at ambient level. The jet-to-target plate temperature ratio (TR) thus ranges from 1 to 2 circa. The investigated jet Reynolds numbers range from 4000 to 10000. The obtained results reveal that heat transfer features are affected by the target plate temperature level, as it plays a role on the interaction between the impingement jets, the spent flow and the manifold surfaces. An in-depth analysis of the obtained results provides valuable information about the extrapolation of ambient test results to engine conditions.

Ignition characteristics of a vertical solid fuel plate with block have been investigated experimentally. For low radiant heat flux, ignition does not occur in a vertical solid fuel plate without block. In the case with the block on a vertical fuel plate, however, ignition can occur by increasing the residence time and the time to absorb the incident radiation flux by fuel vapor in gas phase. The ignition occurs below block and the point varies according to the block location and the block height. As the block height increases, the block locates at higher position, and the hot wall temperature increases, the ignition delay time decreases. Also as the initial temperature of fuel plate rises, the ignition delay time of the solid fuel plate decreases. The temperature distribution of solid fuel plate with block is nearly proportional to the radiant heat flux distribution. Therefore, the effect temperature by natural convection heat transfer is of the same order as that of inhibition of temperature increase by pyrolysis.

Effects of melt temperature on as-cast structure and mechanical properties of AZ31B magnesium alloy

Freeze-drying has been widely used in the production of pharmaceuticals,vaccines and high-valued foods.Foam freeze-drying is a new type of drying technology,in which the sample is foamed and frozen before drying.Compared with traditional freeze-drying method,the new method can reduce operation time and cost significantly.Some foreign researchers have used this method to produce heat-resistant vaccines which can endure higher temperature and remain effective after a longer storage in refrigerator.Up to now,little research about foam freeze-drying has been reported domestically.In this study,newcastle disease vaccine was used as an example to illustrate the procedure of foam freeze-drying method and to test its capability of producing heat-resistant vaccine.The ingredient of the foam freeze drying(FFD)sample included w(trehalose)= 10%,w(hydrolyzed gelatin)=5%,w(pluronic F-108)=3%,w(arginine)=2%,25mmol/L phosphate buffer(pH =7.2).The sample was prepared through the following procedure:1)One milliliter sample was placed on the plate of the freeze dryer and cooled to 15℃;2)then the pressure was lowered to 5Pa and foaming began;3)after one hour the plate temperature was increased up to 31℃at a velocity of 0.7℃/min and kept for another 48hours.The samples made by foam freeze drying were analyzed with thermal analysis and aging test,and were compared with live attenuated samples and heat-resistant samples prepared by traditional freeze drying.The latter two kinds of sample were bought from market(Tianbang Biotechnology Corporation,Nanjing,China).Thermal analysis was done with a differential scanning calorimetry(DSC 200F3Maia,NETZSCH,Germany).The procedure was as follows:1)the sample was cooled to-20℃at a rate of 10℃/min and held for 3minutes;2)the sample was heated to 80 ℃ at the rate of 10℃/min and held for 3minutes;3)the sample was cooled to room temperature at the rate of 10 ℃/ min.Aging test was carried out by placing the sample at 37℃for 10 days and thereafter measuring its EID50.EID50 was determined by vaccination with chick embryo and Reed-Muench calculation method.The appearance of the FFD sample was like sponge,totally different from the flat biscuit-like sample made by traditional freeze drying method.The average glass transition temperature of FFD vaccine was 33.9℃,higher than 30.2 ℃ of live attenuated vaccine,but lower than 40.1 ℃ of heat-resistant vaccine.This means that the heat resistance ability of FFD vaccine is physically better than that of live attenuated vaccine.After aging test the titers decreased for FFD vaccine was 1.1,which was a little higher than 0.8 for heat-resistant vaccine.The latter result was in consistent with the former result.It is clear that FFD vaccine has its own superiority on heat resistance ability,although the formula and operation parameters still need to be improved.Considering its obvious economic prospect,it is worth to carry out further work on the study of FFD vaccine.

Effect of melt temperature on the electrical resistivity and crystallization temperature of Al 91La 5Ni 4 and Al 91Ce 5Ni 4 amorphous alloys

Spectral study of ferrous iron in CaAlborosilicate glass at room and melt temperatures

The structure of Ni-Cu alloys processed by high pressure torsion by 5 revolutions at room temperature (saturation stage) has been studied by the methods of transmission electron microscopy and microhardness measurements. It is demonstrated that moving from copper possessing lower melting temperature and lower stacking fault energy (SFE) to nickel the melting temperature and SFE of which are considerably higher, the submicrocrystalline structure of alloys is markedly refined (by about a factor of 2), whereas the microhardness increases by more than 1.5 times. The simultaneous effect of two factors (changing of homological temperature and SFE) results in the non-linear dependence of these parameters (crystallite sizes and microhardness) on alloy composition.

Conversion of temperature differences to electric voltage and vice versa is the thermoelectric effect. Voltage is created when there is a different temperature on each side of a thermoelectric device and when a voltage is applied to it, temperature difference is created. This is used to attain cooling effect on thermoelectric cooling (TEC) plate. In this project, two TEC plates are used on two sides of copper plate heat exchanger to build an air cooler of portable type. Two heat sink fans with fins are adjusted with the TEC plates. Water is pumped through the ice box inside the cooler and cooled water gets circulated through copper tubing and flows back to ice box. The air gets cool from the cooled tube surface. COP of the system was found to be approximately 7. The system is useful due to its affordability of less cost requirement during the manufacturing process. The humidity of the environment is not changed due to cool air supplied by the system, as there is no direct contact of warm air and cooled water. The advantage of using it in more humid hot conditions is the motivation of the project.

This paper deals with the performance evaluvation of portable mist humidifier, for producing a cooling effect in a specified area. A humidifier is an electrical device that increases the humidity of an environment. So the room temperature got reduced with the help of increasing the humidity. This devise provides a cooling effect at low cost without health hazards. The experimental arrangement made with the components of axial fan, copper tubes, hydraulic pump, nozzles, respectively. The misting nozzles are placed into the holes which are made in the copper tube and the copper tube is fitted over the frame on the axial fan. The hydraulic pump is kept in the water tank to circulate the water to the copper tube. When the water flows through the tube it emits water droplets with the help of misting nozzles. Due to the high-speed axial fan, the emitted water droplets are sprayed into the atmosphere as a mist. When there is a increase in the moisture content there will be decrease in room temperature. Due to this effect the room temperature has been decreased by 12% with the help of humidifier.

This paper is concerned with thermo-elasto-plastic dynamic response of a conductive plate in a magnetic pulse field. The influence of the strain rate effect and the temperature effect are taken into account for the electromagnetic elasto-plastic dynamic transient response and deformation of the conductive plate which made of strain-rate sensitive materials. The Johnson-Cook model is employed to study the strain rate effect and the temperature effect on the deformation of the plate. Basic governing equations are derived for electro-magnetic field considering the eddy current. The analysis includes the elastoplastic transient dynamic response and the heat transfer of a conductive rectangular plate, and then an appropriate numerical code based on the finite element method to quantitatively simulate the electro-magneto-elasto-plastic mechanical behaviors of the conductive rectangular plate. The numerical results indicate that the strain rate effect has to be considered for the conductive plates, especially for those with high strain rate sensitivity. Comparison of the influence of the temperature effect on the deformation of the plate with that of the strain rate effect shows that the influence of the temperature effect on the deformation of a plate is not significant.

The effect of temperature on an end-cell plate in a proton exchange membrane (PEM) fuel cell stack is presented in this paper. Numerical analysis and experimental work investigated the impact of a heat exchanger filled with metal foam on the end-cell plate used for cooling a PEM stack. One side of the edge plate was subjected to constant heat flux (1.55 W/cm2) while the other side was insulated. A metal foam with a pore density of 40 and having a porosity of 60% was analysed. The model was simulated in ANSYS R3-CFD, and the thermal problem was solved using the local thermal non-equilibrium (LTNE) to investigate the heat transfer between the fluid and solid phases. The thermal solution studied the effect of metal foam heat exchangers at different airflow velocities between 0.2 and 1.5 m/s on end-cell plate’s temperature. The results showed heat transfer enhancement in plate temperature, proving that the use of the LTNE assumption illustrated the difference between the end-cell plate and fluid flow temperatures. The effect of inlet air velocity on the plate temperature was also examined. An experimental model of a commercial PEM stack was constructed out of aluminium. This model was tested at the same conditions as those employed in the numerical solution. The heat generated by a fuel cell was simulated by a surface heater providing the same heat flux as the actual PEM cell. The numerical and experimental results for the end-cell plate for both at flow direction and different inlet velocities were assessed. There was a good agreement between the numerical and experimental results.

The Cabinet-type ERK solar dryer is manufactured by a temperature distribution process so that the temperature inside the appliance is well distributed. The cabinet-type ERK solar dryer comprises several components to maintain the water content, including a drying oven, air blower, heat-resistant pipe, hot water pump, thermostat, heat exchanger, and heater. These tools are used to convert heat radiation into conduction or convection so that the dried agricultural products' water content is relatively low. The data needed to show the quality of the tool include temperature on temperature received by the wall (Tw), absorbent plate (Tp) and room temperature (Tr). And as for other supporting data including the environmental air/ ambient temperature (Ta) and solar irradiation (I) for optimal tool usage time. The experiment results for 5.5 hours, as many as 23 measurements with time interval 15 minutes, obtained a relatively unchanged temperature distribution. During that time, the average temperature received by the wall (Tw) was 41.26 °C, while the middle plate temperature (Tp) was 40.65 °C and room temperature (Tr) was 40.71 °C. Thus, the temperature in the Cabinet-type ERK solar dryer is well distributed. The distribution percentage between wall temperature and plate temperature is 98.52 %, while wall temperature and room temperature are 98.67 %. The result indicates that the Cabinet-type ERK solar dryer is potential as a drying device for agricultural commodities. It is hoped that the Cabinet-type ERK solar dryer will be an alternative to a drying system that can improve the quality of agricultural commodities for farmers in Indonesia

Recently, injection molding process has generated growing interest, exhibiting great potential to easily fabricate unique polymeric materials for industrial applications. To increase the sustainability of the process, determinative parameters and their effects should be examined. This study focuses on the effect of melt temperature on as-injection molded product, thereby high-density polyethylene samples were fabricated by performing three different melt temperatures (180, 190, and 200 °C), and subsequently, their mechanical, thermal, and morphological and surface quality properties were examined. The results showed that higher melting temperature lowered crystallization rate and decreased the strength of tensile and bending; however, it increased crystal lamellar thickness and impact strength. Moreover, the type of fibrillation changed with the temperature. Moreover, defects formation increased with the temperature. For further application, the effect of the temperature on surface quality was discussed. This work will provide a guide for manufacturing injection-molded products at desired properties by arranging melt temperature.

The structure, phase composition, and thermal stability of the industrial zirconium alloys, namely, E110 (Zr–1% Nb) and E635 (Zr–1% Nb–0.3% Fe–1.2% Sn), which are subjected to high‐pressure torsion (HPT) at room temperature (RT), 200, and 400 °С have been studied. HPT of Zr‐alloys at RT (10 revolutions) leads to the formation of grain–subgrain nano‐sized structure and to increase the microhardness by 2.1…2.8 times. The increase in the HPT temperature to 200–400 °С leads to the increase in the structural‐element average size. The structural‐element size in the complexly alloyed E635 alloy in all cases is lower compared with the E110 alloy. The hardening of the alloys after HPT at RT and 200 °С is close, and at 400 °С is much less. HPT initiates the α‐Zr → (ω‐Zr + β‐Zr) transformation, which is the main factor for alloys hardening. The α‐Zr → (ω‐Zr + β‐Zr) transformation in the E635 alloy occurs less quickly. The maximum amount (ω‐Zr + β‐Zr) phase in the structure of the alloys is observed after HPT at RT and 200 °C, and the minimum − at 400 °C. During heating, the alloys undergo the reverse (ω‐Zr + β‐Zr) → α transformation which depends on both the alloy composition and HPT temperature.

Glass-fiber reinforced polymer (GFRP) composites offer significant advantages, including high performance, light weight, excellent insulation, and corrosion resistance. It is an ideal material for transmission towers as a replacement for steel. Understanding the performance of GFRP composites in service environments is a key issue to promote the application. In this paper, the influence of low temperature on the static and fatigue properties of GFRP plates for composite transmission towers is investigated through tests conducted at room temperature (RT, 20°C) and low temperature (LT, −40°C). The results show that the elastic modulus, ultimate strength, and fatigue life of GFRP plates are substantially enhanced at LT. The effect of temperature on Poisson’s ratio is limited. The S - N - T model with reference to the Arrhenius model can accurately describe the relationship between stress level, fatigue life, and test temperature of GFRP plates. In addition, the relationship between the normalized fatigue stiffness and the normalized fatigue life of GFRP plates is described using a three-stage fatigue damage prediction model. The results show that the fatigue stiffness degradation trend predicted by the model aligns closely with the test results.