Iraqi journal of mechanical and material engineering

In this research, the effect of eggshell powder on some mechanical and physical properties of natural rubber, which comprised each of tensile strength, modulus of elasticity, elongation, hardness, resilience and specific gravity, were studied. The egg shells were collected and dried by exposed to sun for (3) days and they were milled by electrical mill, the set of sieves were employed to get on egg shell powder by the suitable size. The egg shell powder was added to NR from 5 wt % to 25 wt % and then tensile, hardness, resilience and specific weight tests were carried out for
prepared specimens. The results showed that the hardness and modulus of elasticity, specific weight increased with increasing of the powder. The hardness was (35 IRHD) for pure rubber, while was (49.3 IRHD) at percent of powder (25 wt %) . It was observed that the tensile strength, elongation and resilience decreased with increasing of powder. The tensile strength was (21.96 MPa) for pure rubber, while was (9.21 MPa) at percent of powder 25 wt %. This work exists with a good replacement for synthetics fillers avoiding their toxicity and their highly cost and reducing of the
environmental pollution.

The coat in the burning zone play an important role in cement industry and energy keeping, not only it protect the refractory bricks but also affect the type of clinkers produced so it is a good idea to make some researches about this coat In this papers the model produced by Sepehr Sadiqhi et.al. 2011 depending on the measured process variables and scanned shell temperature, will reviewed to estimate the thickness of coating at Kufa cement kilns. The Aging factor will be entered to represent the phenomena when fused clinkers transform to solid and calculate the time required for making this coating. The estimation of thickness in this model was depending mainly on the difference
between the inside temperature gotten from the model and outside temperature measured by kiln shell scanner at burning zone. The model was applied on two kilns (2 and 3) at Kufa plants. The difference between theoretical and practical results for measuring thickness at kilns 2and 3 was 4.43 and 3.92cm respectively , the time required for
formation the stable coating was 24 hr or 960 rpm.

Two dimensional laminar natural convection heat transfer in a square cavity with horizontal and vertical triangular partitions is studied by ANSYS 12.1. The computational procedure based on finite element technique is used to solve equations of continuity, momentum and energy. Two isothermal boundary conditions are considered. The segments of horizontal and vertical walls of the enclosure are maintained at hot temperature, while the triangular partitions surfaces are maintained at cold temperature. Air was chosen as a working fluid with Prandtl number of 0.71. A parametric study is carried out using following parameters: Grashof number from 104 to 106, Dimensionless partition height from 0.2l to 0.8l of half height or width of the enclosure. Representative result illustrating the effect of the above parameters on the contours maps of the streamlines and isotherms are reported and discussed. It was found that, the convective heat transfer is greatly influenced by increasing the partitions height. Increasing the partition height causes an increase in heat transfer due to increasing cold surfaces, vise verse, causes decreases in the Nusselt number due to decrease in the flow speed.

In the present study, the effects of multiple strip footing configurations on the bearing capacity and load-settlement curves of sandy soil were investigated using nonlinear finite element analysis. Two and three strip footings resting on sand were analyzed. In each case, different footing distances were applied for the purposes of comparison among all of the results. From these results, it was observed that the load responses of multiple strip footings are similar to those of the single strip footing at distances greater than four times the footing width. Also, a design equation necessary for quantifying the values of the bearing capacity ratio for the different multiple strip footing configurations were derived. Experimental test results from the literature were selected to verify the used nonlinear finite element method.

This research includes experimental and numerical analysis using finiteelement method by ANSYS11 package to study effect of reinforcement of Aluminum–Silicon with ceramic particles (Alumina) for different beam width (12, 14 and16mm) on the hardiness and bending properties. The composite material is produced using the vortex technique by cutting the base alloy to small pieces and put inside steel crucible. Put the steel crucible inside gas furnace in temperature (700oC). The electrical mixer used to vortex the mixtureand adding the aluminum oxide particles (Alumina) (5% and 10%) and after thatpouring the melting in metallic mold. The results of the study showed that Vickers micro hardness increased from(HV=105) for pure Aluminum –Silicon alloy to (HV=127) with (10%) Alumina, alsothe tensile strength increased from (95 Mpa) to (135 Mpa). The maximum flexuralstrength was (451 MPa) and the maximum shear stress was (33 MPa) at (width=16mm) with volume fraction (10 %) of Alumina. the maximum strain decrease withincrease volume fraction of Alumina. The experimental and finite element resultsobtained are approximately agreement.

In the current research (which is done in the laboratories of Babylon TiresFactory), Studying the effect of molybdenum trioxide upon the characteristics ofcuring system of styrene- Butadiene rubber (SBR) has been carried out by usingOscillating Disk Rehometer according to the ASTM D-2084 specification. TheResults showed that the effect of addition (Molybdenum trioxide) to styrenebutadiene rubber in proportions of (0, 7.5,15,22, and 28) phr (per hundred percent). Molybdenum tri-oxide uses to enhance the hardness, the tensile strength andReometric properties of the rubber. The result showed that the cure time and scorchtime decreased when torsion stress and filler content increased also the tensilestrength and hardness advanced with the filler content increased. The hardnessdeveloped significantly from (62) to (68) shore (A) when molybdenum trioxide addedtherefore the rebound and elongation decreased.

In the present study the rubber was added to novolac resin as a binder toprove the mechanical properties. Glass fibers and steel fibers were used at differentratios as a reinforcing fibers, molybdenum trioxide and calesuim carbonate as filler, zirconium oxide as abrasive material and copper sulfides as a lubricant. The currentwork investigates the characteristics of three resins: (i) SIR with novolac resin (ii)NBR with novolac resin (iii) SBR with novolac resin. The addition of SIR or NBRwas used because it undertakes the high temperature and has good chemance. The SIR was used with deferent weight ratio of fibers to compare its efon the mechanical properties. The samples were prepared by using cold pressing at(250MPa) .The samples were cured at (80oC). Wear test was carried out by using pinon disc test system. Results from the present study showed that the friction coefficientand wear rate varied with the change of the resin and fibers ratio. The result showedthat NBR and SIR addition proved best in terms of impact strength, hardness, wearrate and friction coefficient result but SBR showed poor result. The NBR addition hadbetter wear results than SIR. The high ratio of fibers decreases the wear rate andincreases the impact strength and friction.

The coat in the burning zone play an important role in cement industry and energy keeping, not only it protect the refractory bricks but also affect the type of clinkersproduced so it is a good idea to make some researches about this coatIn this papers the model produced by Sepehr Sadiqhi et.al. 2011 depending on themeasured process variables and scanned shell temperature, will reviewed to estimate thethickness of coating at Kufa cement kilns. The Aging factor will be entered to representthe phenomena when fused clinkers transform to solid and calculate the time required formaking this coating.The estimation of thickness in this model was depending mainly on the differencebetween the inside temperature gotten from the model and outside temperature measuredby kiln shell scanner at burning zone. The model was applied on two kilns (2 and 3) atKufa plants. The difference between theoretical and practical results for measuringthickness at kilns 2and 3 was 4.43 and 3.92 cm respectively , the time required forformation the stable coating was 24 hr or 960 rpm.

In this paper, an experimental and theoretical study of natural convection heat transfer in a closed ends annulus region formed by a heated square cylinder placedconcentrically in a larger isothermally cooled circular cylinder. Experiments arecarried out for Rayleigh number based on the equivalent annulus gap length rangesfrom 103 up to 106. Different aspect ratios, 0.2 up to 0.5, are considered. Thenumerical simulation for the problem is carried out by using commercial CFD code(FLUENT 6.3).The average Nusselt number from the experimental results iscompared with that obtained from the CFD code. The fluid flow and heat transfercharacteristics for different operating and geometric conditions are illustrated throughstream lines and isotherms contours that obtained from the CFD code. The resultsshowed thatas the aspect ratio increases the heat transfer rateand the average Nusseltnumber increase. Also the result showed that as Rayleigh number increases theaverage Nusselt number increases.

Two dimensional laminar natural convection heat transfer in a square cavitywith horizontal and vertical triangular partitions is studied by ANSYS 12.1. Thecomputational procedure based on finite element technique is used to solve equationsof continuity, momentum and energy. Two isothermal boundary conditions are considered. The segments of horizontal and vertical walls of the enclosure are maintained at hot temperature, while the triangular partitions surfaces are maintainedat cold temperature. Air was chosen as a working fluid with Prandtl number of 0.71.A parametric study is carried out using following parameters: Grashof number from104 to 106, Dimensionless partition height from 0.2l to 0.8l of half height or width ofthe enclosure. Representative result illustrating the effect of the above parameters onthe contours maps of the streamlines and isotherms are reported and discussed. It wasfound that, the convective heat transfer is greatly influenced by increasing thepartitions height. Increasing the partition height causes an increase in heat transfer dueto increasing cold surfaces, vise verse, causes decreases in the Nusselt number due todecrease in the flow speed.

This paper describes a new finishing process using magnetic abrasiveswere newlymade to finish effectively brass plate that is very difficult to be polished by theconventional machining processes.Taguchi experimental design method was adopted forevaluating the effect of the process parameters on the improvement of the surfaceroughness and hardness by the magnetic abrasive polishing.The process parameters are:the applied current to the inductor, the working gap between the workpiece and theinductor, the rotational speed and the volume of powder. The analysis of variance(ANOVA) wasanalyzed using statistical softwareto identify theoptimal conditions forbetter surface roughness and hardness. Regressions models based on statisticalmathematicalapproach by using the MINITAB-statistical software for both surfaceroughness and hardness were obtained.Experimental results indicated that rotationalspeed is the most significant parameters on change in surface roughness(ΔRa), and forchange in surface hardness (ΔHa), volume of powder is the significant one.As a result, itwas seen that the magnetic abrasive polishing was very useful for finishing the brassalloy plate.