Papers by Keyword: Thermal Insulator

Abstract: Every year, the Philippines experiences hot and rainy weather. For those who choose to remain at home, summer feels like torture. So, Filipinos have no choice but to turn on their air-conditioning system, which can cause their electricity bill to skyrocket. Corn husk fibers, being a waste product, have great potential to be applied in home textiles, home furnishing, carpet, rugs, and packaging of food grains and crops. The researchers thought of making thermal insulation ceiling panels made of corn husk fibers. The study yielded a result of 0.119 W/m.K for thermal conductivity using a calibrated hot box, below the 0.25 W/m.K maximum threshold for thermal conductivity value. Furthermore, its fire resistance characteristic made it less susceptible to small fire attacks. It was also found that the insulator has 2.19% and 8.42% water absorption values for short and long-term soaking, which is less than the 40% range value for water absorption. Hence, it can be said that it is an excellent thermal insulator.

Abstract: This research attempted to prepare thermal insulation material made of naturally occurring products. Natural rubber (NR) foam comprised of ground rice husk as a filler was practically investigated. STR 5L played as a solid commercial NR was mixed with various chemicals on a two-roll mill. Dicumyl peroxide (DCP) and di-nitroso pentamethylene tetramine (Supercell DPT) were employed as curing and blowing agents, respectively. Physical, mechanical and thermal insulation properties of NR composite foams were studied with various particle sizes (mesh 40 and 60) and quantities (0-80 phr) of the ground rice husk. Cure characterization and preparation of all NR compounds were performed at 160 °C. As a result of tensile properties, the bigger particle size (mesh 40) and the highest amount of the ground rice husk at 80 phr resulted in the maximum tensile strength and elongation at break (%) of the NR composite foams. The thermal insulation property of the NR composite foams carried out by ASTM C177 revealed that the lowest thermal conductivity among three representative NR formulations was found to be 0.0862 W/m.K for the NR foam reinforced with the ground rice husk mesh 40 at 20 phr. Closed cell NR composite foam with a smaller amount of ground rice husk particles provides good compressive strength and heat insulation properties but not good tensile properties.

Abstract: In this work, the authors tried to solve a typical problem of inexpensive 3D printers using FDM technology: material clogging of the hotend. To cope with the problem, it is necessary to solve the problem of optimization the temperature regimes of the hotend. For this, the temperature fields of the heating device were simulated taking into account the physical properties of the printing materials. Modeling was carried out using the ANSYS software package, the verification of theoretical calculations was carried out in a full-scale experiment. The data obtained was used to upgrade the 3D printer hotend.

Abstract: Closed cell rubber sponge applied as thermal insulator made from solid natural rubber (NR) was prepared by using Supercell DPT as a blowing agent. Rubber chemicals and STR 20, solid NR, were mixed on a two roll mill prior to prepare the specimen by hot press machine. Curing behaviors of the compounded solid NR with various types of sulfur and peroxide vulcanizations were characterized with moving die rheometer (MDR) at 150 and 170°C. Tensile and compressive strengths of the rubber insulator were measured by universal tensile testing machine followed by ASTM D412 and ASTM D395, respectively. Bubble size of the blown up rubber was inspected by an average maximum length of the bubble by using optical microscope. It should be notice from the experimental that all rubber formula both of sulfur and peroxide systems showed loading percentages to completely expand in a mold by about 38 to 48. Rubber insulator blown up with Supercell DPT used by semi-efficient vulcanization (semi-E.V.) unconcealed predominant results among all curing systems so that further investigations of the formulation as heat stuff will be discussed in next paper

Abstract: Already, we developed a high porosity alumina foam. However, alumina has high thermal conductivity about 36W/mK at room temperature, and it need to achieve to high porosity to decrease thermal conductivity to for application of refractory bricks. Therefore, high porosity mullite refractory brick is developed using GS (Gelation of Slurry) method that is already developed for production of high porosity metal foam. Appling this method to production of mullite foams, the ceramics foams from 93 to 97% porosity can be produced. Also, their thermal conductivities are proportional to densities and obey to Ashby-Glicksman model. Its thermal conductivity is about 0.07W/mK when density is 0.1 g/cm3. The high porosity mullite foams achieved enough thermal insulating properties for refractory brick.

Abstract: After this tragic accident of Colombia's shuttle the continuance of these spatial functions were encountered with ambiguity and lots of suspicion was formed in the NASA officer's brain. The burst was formed because of the defect which was made in the outer insulator fuel tank, a insignificant piece of insulator that was separated while throwing the Colombia's shuttle from the fuel tank under the aerodynamical force of throw (while separating the tank from the shuttle) and it hurts the ledge of the left wing of the shuttle in the place of ceramics insulator defect and shuttle's thermal safety system. It was happened in throwing the shuttle discovery too, however they relief the damaged parts through a spatial marcher in the space and they turn it to the earth with so much presentiment. In this essay we present a new design for the fuel tank and shuttle. In this model, shuttle is set on the top of the fuel tank and while separating the tank from the shuttle, the probable separating pieces, wouldn't be defect to the shuttle. In this procedure because the tank has a motor, a cart landing and a control system, it is again useful and would make the economy in the charges. In this Method by putting shuttle on top of the tank, it may not make any hurt to the thermal shield and there weren't any accident accession like the Colombia's shuttle accident and There wouldn't be any requirement to design a new space crafts with the passenger to go and return, and according the heavy costs of the researches, temptation and long time providence it would be much and According to probability of returning the fuel tank to the earth, in other throwing there would be multiple providence that can be a justification for this project And also Changing the tank place improves the aerodynamical coefficient in comparison present shuttle's picture that will cause to reduce using the fuel.