Iraqi journal of mechanical and material engineering

This study represents an attempt to reduce the drying time of wet grain wheat of the fluidized bed dryer (FBD), using straight blades, and debates the effect of stirrer on the whole drying time at different static bed heights. Experiments for FBD were conducted at the low velocity of air supply (1.45 cm/s) with moisture content for grain wheat 12% and ambient temperature of 37°C for each static bed height (9, 12, and 15 cm). FBD was made from a glass cylindrical column with inside diameter 4.6 cm, outside diameter (5.2 cm) and length (116 cm). The results showed an enhancement of (12- 20.5%) in the total drying time for bed height (9 and 15) cm, respectively. Also, increasing bed height from 9 cm to 15 cm possesses no influence on the equilibrium content of moisture in both techniques of drying either stirred fluidized bed or conventional fluidized bed.

The aim of this work is to test the effectiveness of new thermal insulation material formed from semi-spherical Perlite expanded particles for liquefied petroleum gas (LPG) tanks. Five different samples of semi-spherical particles of (68.8, 90.4, 300.5, 1211000, 1861000) *10-9 m diameter are used as a new thermal insulating material in this work. To simulate the LPG tank wall, a stainless-steel plate of a thickness (3mm) is coated with this material and subjected to a resistive type flat plate heater. The thermal insulation coating thickness was (0.5mm to 2mm). This plate is subjected to different power loads namely (650, 1260 W/m2). Results show that increasing the insulation expanded particle size increases the difference in temperatures on both sides of the insulation layer. The first three sizes of the insulation material reported a temperature difference at both sides of the coating layer is about 18 oC, while that for the fourth and fifth size are 20 oC and 25 oC respectively since larger expanded particles size has higher air content that enables them to reduce and delay heat transfer. The thermal conductivity of coated thermal insulation with large Perlite particle size is (0.25 W/m.K), while that for small size is (0.42 W/m.K). The previously reported thermal conductivity for Silica granules is less than 0.4 W/(m.K)for insulation thickness of (50 mm), while that for binderless cotton stalk fiberboard (BCSF) is ranged from 0.0585 to 0.0815 W/m K for board thickness 25mm. The indicated thermal conductivity for coconut husk and bagasse insulation boards is 0.046 and 0.068 W/mK for board thickness 25mm. So utilizing Perlite expanded particles as an insulation material is superior since it is a slim layer not exceeded 2 mm.

The corrosion of carbon steel in 0.3 and 3% mass hydrochloric acid containing the concentration range 50-800 ppm of Thiourea (Th), Quinoline (Q), Dliethylamine (DEA) and Pyridine (P) were investigated using electrochemical methods. The investigation aims to mention the best organic inhibitor among several compounds to be used in synergic inhibitors. The inhibition efficiencies of thiourea and quinoline are better than pyridine and diethylamine in 0.3 mass% HCl. Thiourea is better than quinoline in 3 mass% HCl and its inhibition efficiency is 83.7%. Generally, the corrosion rate decreases with increasing inhibitors concentration. Diethylamine and pyridine are not effective. The polarization curves indicate that the used inhibitors influenced the cathodic reaction more than the anodic reaction and they are considered as a mixed type inhibitors.

There is high consumption of oxygen cylinder valves due to incorrect application of valves, therefore, this research will study the possibility to modify Brass alloy that used to produce cylinder valves and reduce their erosion that happens under the use of valve. The main type of brass that used to make cylinder valve is CW713R which contained aluminum with percentage of 1.3-2.3% with hardness of 174 HV. Therefore, the effect of aluminum element on the properties of brass alloy will study to find the best and the optimum percentages that can be added to improve the hardness and machinability of cylinder valve. Brass scrap was melted using oil fire furnace and aluminum element was added before it cast. Then, the melting liquid was poured on steel die casting mold. The result shows that the hardness Brass cylinder valve was increased by increasing the percentage of aluminum element. It is raised from 206 to 605 HV. But when the percentage of aluminum reached 10 % the Brass material becomes brittle and difficult to machine. The best percentage of aluminum that can be added to brass alloy lies in the range of 2.5 – 5%.

This work focuses on studying the effect of adding nanoparticles on the mechanical properties of the alloy (Al-4%Si) reinforced with carbon nanotube at a different weight percentage (0.25,0.5 and 1%wt). prepared the base alloy and the reinforced materials in a casting followed by solution heat treatment in the furnace at temperature 520ºC for 2 hr. , then artificially aged immediately at the temperature of 185 Co for (2-8 hr.). A detailed characterization of the composite metal matrix structure has performed using XRD, microhardness and wear rate measurements. The results demonstrated that the values of the hardness test increase with an increasing weight percentage of CNTs, this enhancement wear properties of the base alloy reinforced for all percentage of carbon nanotubes additive especially at the weight percentage of 0.5%.

The degradation of waste plastics in the environment is such an essential issue for Earth protection. This study indicated the importance of using waste bottles to produce recycled depolymerization Polyethylene Terephthalate (DPET). The bubble column reactor technique and its effect in the depolymerization process have been investigated. The DPET with Poly-methyl methacrylate (PMMA) has been used to fabricate the hybrid polymer to improve the mechanical properties. Thus, different percentages (1, 2, 3, 5, and 10 %) of (DPET) are used to surmise its repercussions on the mechanical properties of the polymer. These ramifications were studied through a sequence of research laboratory tests, including tensile strength, Charpy impact, and shore-D hardness, and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The results show a development interest, especially for impact strength and surface hardness, where both tests show compatible results, especially at (10%) of DPET. At the same time, maximum results of tensile strength are at (3%). FTIR analysis shows a chemical reaction between DPET and PMMA, which significantly improves the characteristics and makes it a wide range of available applications.