Iraqi journal of mechanical and material engineering

The impact of time ,speed of sliding and load on wear qualities of hypereutectic aluminum 18% silicon alloys by pin on disc apparatus is actualize. silicon alloys are most prosperous
materials due to include hardness and resistance of wear compared to other alloys or any
other composites and by using die-casting, many alloys are prepare at diverse of magnesium
additions (2.5, 3.5, 4.5)wt% to the Al-18%Si- alloy in order to study the effect of
magnesium additions on the wear rate The microstructure of prepared alloys is examine by
optical microscope.. The experiments of the wear are carry out on a set of specimens under
different times ranging from (10 to 40) minutes, and loads (0.5 to 2) kg, and diverse sliding
speeds (2.5 to9) m /sec the results of microstructural show the existence of primary silicon
(Si) and phases of eutectic silicon and adhesion wear properties decrease when magnesium
was added to aluminum at all percentages. It was concluded that decrease in hardness and
increase in ductility contribute

A performance study was conducted on the combined cycle power plant (CCPP), which is one of the most important options for replacement and repowering of the available steam power plant. The thermodynamic performance of these plants depends on the ambient temperature which varies considerably from one season to another. The objective of the current work is to investigate the effects of these variations on the performance of combined cycle power plants. In this study AL-Mussaib thermal power plant has been chosen for repowering, for this purpose, AL-Khairat gas turbines are used and the effect of duct burner is investigated. The repowered combined cycle power plant (RCCPP) consists of four gas turbines and four heat recovery steam generator (HRSG) with one steam turbine was associated with the unit in this model. The theoretical analysis was made according to both first and second laws of thermodynamic analysis. A generalized computer program was prepared by Fortran 90 for this purpose. It is found that the net power output, thermal and exergy efficiencies of the RCCPP increases as the ambient temperature decreases. The mass flow rate of steam decreases with the increase of ambient temperature at constant compressor pressure ratio and turbine inlet temperature (TIT). The exergy destruction in the combustion chamber and HRSG decreases while, the exergy destruction of the condenser increases greatly as the ambient temperature increases

An experimental investigation was carried out to study the effect of Large Eddy Breakup Devices with of circular ribs on one heated wall of a rectangular duct with fully developed turbulent flow , on heat transfer and flow characteristic. The artificially roughened duct has an aspect ratio (W/H) of 10, hydraulic diameter of 72.72 mm, relative roughness pitch (P/e) of 10 and relative roughness height (e/Dh) of 0.05. The experiments were conducted by varying airflow rate in terms of Reynolds number ranging from 3.2x104 to 6.2x104 and constant heat flux of 600 W/m2.The heat transfer and friction characteristics of the duct were compared with those of a smooth duct under similar experimental conditions. It was found that there was a significant enhancement of Nusselt number for combined high Reynolds number (2.6) and friction factor (3.47).

The interaction of fatigue and laser peening with different surface coatings was studied for 2017A-T3 aluminum alloy under stress ratio R= -1 and room temperature (RT) .
This interaction is a major issue in the practice life assessment of aircrafts. The current work examined the effect of laser surface with different coatings i.e. ALP (Air laser peening), BPL (Black paint laser peening) and WLP (Water laser peening) on cumulative fatigue. The experimental results observed that the fatigue strength was improved by 18% and 35% under BPL and WLP respectively. A new non-liner damage model was derived to predict the cumulative fatigue lives . This model showed safe and satisfactory predictions for unpeend and peened specimens for all cases of surface coatings. While Miner theory indicated not always suitable for life prediction of cumulative fatigue loading .

The research includes making mixtures of cellular concrete (thermostone) waste powder with different percentages of glass waste powder and measuring some mechanical and physical properties of the resulting composite material of glass and thermostone waste. The properties (porosity, absorption, density, compression, and hardness) were tested on two types samples, first type without addition of glass (standard sample) and the second with addition of glass (10, 20, 30)% by weight of thermostone waste.
The results showed that both of porosity and absorption of thermostat waste powder are
decreasing with increasing of a glass percent, where porosity decrease from 63.38% to
28.74% and absorptions from 46.88% to 16.78%. Density, compression and hardness were
increased with increasing of glass percent, where density increased from 1.351 to 1.712
gm/cmP
3
P, compression from 9.7 to 13.8 Mpa, and hardness from 22.7 to 99.7.

In this paper, Aluminum – 12wt% Silicon alloys reinforced by cerium oxide (CeO2) nano powder with a different percentage (1, 2, and 3 wt.%) were prepared by powder technology method. Wear, porosity, apparent density tests were conducted for composite materials and reference alloy. The results showed that there is a slight change in the density and increases in the porosity of nanocomposite materials compared to reference alloy. The wear rate decreases with the increase in the proportion of the reinforced particles for the reference alloy as well as the wear rate increases with increased applied load.

This study present experimental and numerical analysis of airflow distribution through surgery operating room by using CANOPY. The experimental work include an experimental operating room in laboratory of Babylon University. Two cases were taken in analysis of air distribution. Both cases have a ceiling air supply system and the different between then was in design of air supply system. Both cases consist of patient bed, surgical staff around, overhead light, surgical light and electrical devices. Air is exhausted through four exhaust grills located in four corners at latitude about 0.25 m from ground. In numerical work a three-dimensional model of the experimental operating room was developed in Gambit and analyzed in FLUEN6.3.26.The results showed that ceiling system is a good ventilation system for air distribution in operating room. Curtain air system gave more protection from laminar flow system where isolate the patient bed from the rest of the room and air velocity above the patient be low. FLUENT program give a good and close results to reality .Good
agreement between numerical and experimental results was obtained inside experimental
operating room.

Due to the enjoyment of poly methyl methacrylate material of significant advantages in mechanical and physical properties, which encouraged many researchers in recent years working on the used it’s as a prosthodontics denture base material. In the present research, efforts are made to develop the properties of PMMA resin that used for upper and lower prosthesis complete denture, by addition four different types of nanoparticles powders, which are fly ash, fly dust, zirconia and aluminum that added with different ratios of volume fractions of (1%, 2% and 3%) to poly methyl methacrylate (PMMA), cold cured resin (castavaria) is the new fluid resin (pour type) as a matrix. In this work, the Nano composite and hybrid Nano composite for prosthetic dentures specimens, preparation was done by using (Hand Lay-Up) method as six groups which includes: the first three groups consists of PMMA resin reinforced by fly ash , fly dust and ZrO2 nanoparticles respectively, the second three groups consists of three types of hybrid Nano composites, which includes ((PMMA: X%nF.A)+(1%Al+3%ZrO2)), ((PMMA: X%nF.D)+ (1%Al + 3%ZrO2)) and ((PMMA - nZrO2)+(1%F.A + 3%F.D)) respectively. PThe flexural and impact tests results
show that the values of the flexural strength, Maximum Shear stress, flexural modules,
impact strength and fracture toughness increased with the addition of nano powders (fly ash,
fly dust, zirconia and aluminum). And the results showed that the maximum values of
flexural strength and Maximum shear stress reaches to 101Mpa and 2.4738Mpa respectively
for (PMMA: 2%nF.D) Nano composite. Moreover, the results showed that the maximum
values of flexural modules for hybrid Nano composite ((PMMA: 3% nF.A) + (1%Al +
3%ZrO2)) reach to 13.95 Gpa, whereas the maximum values of impact strength reaches to
7.8KJ/mP
2
P for (PMMA: 1% nF.D) Nano composite. And, the results showed that the
maximum values of fracture toughness for Nano composite reach to 26.8 Mpa.mP
1/2
P for
(PMMA: 3% nF.D) Nano composite.

In the present paper, an experimental study has been carried out to study the drag reduction in turbulent flow inside a tube by using surfactant with salt additives, where this phenomena used in many industry applications. Therefore, the flow inside a pipe with high volumetric flow rate requires high power to transport it, so this needs large number of pumps to push it for remote distances and this pumps require great amount of fuels and cyclic maintenance ,so the additives reduce the number of pumps that is required to pump the liquids and so this decrease the cost of pumps, the fuel and maintenance or increases the volumetric flow rate at constant pressure drop. The CTAB surfactant has added with concentrations of 1000,1500 and 2000 ppm, and the salt that is NASAl has added for water at 2000 ppm CTAB concentration with 200 and 400 ppm concentration. The study has excuted with different values of Reynolds number that are 33418,44557,55697, 66836, 77976 and 89115,.Different angles of pipe inclinations has used through the work which are 0˚,3˚and 6˚. The experimental results has correlated by using SPSS program, and solved by multiple nonlinear regression analysis. The power law has found to be the optimum relation that may fits with the data that has obtained from the experimental work .

Because of the environmental pollution and common use for gasoline fuel in our country Iraq, the wide used for cars in the transport sector and the increasing number of cars day after day, it is important to search for alternative fuel to operation the internal combustion engines. In this work, the practical results have been obtained through the experiments to evaluate the use of Gasoline and plastic oil extracted from waste plastic in spark ignition engine. The research aims to study the effect of using the plastic oil in spark ignition engines without any modification of the engine. In this study, the test was conducted on a single - cylinder, 4-stroke SI engine runs at a constant speed, by using of gasoline and mixed with the plastic oil proportions (10%, 20%, 30%, 40%, and 50%) by volume. The brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), and exhaust gas emissions such as: carbon monoxide (CO), carbon dioxide (CO2), and unburned hydrocarbons (HC) are measured. As well as the differences in the engine performance have been found which works by a gasoline mix with plastic oil, this provides better performance of the engine while that a calorific value for the plastic oil is the highest. Hence the experimental results have shown that a 50% proportion of plastic oil blended with gasoline can be the alternative fuel for the operation of spark ignition engine without any modifications .

This work investigated on the corrosion behavior and roughness of Ni-Cr alloy as dental restorative. Alumina with three weight percentages (1, 5 and 10%) added as reinforcement to fabricate Ni-Cr/alumina composites. Corrosion behavior was tested in artificial saliva at 37+1 oC and pH=4.4. The data of corrosion indicated that the addition of alumina led to reduce the dissolution of metals in base alloy due to the enhancing of Cr2O3 passive film and producing Ni3Al phase in matrix. The roughness of surface was reduced for composites compared with base alloy (Ni-Cr) which is important factor to reduce the accumulation of bacteria on restorative materials in mouth; this reduction is due to the formation of ductile Ni3Al compared with brittle Ni2Cr3 in composites.

The present work aims to recycling of tainted sediment filters that used in water purification and desalination in order to reduce the environment contaminations. In this research, the tainted Polypropylene sediment filters we are used as strengthening phase in unsaturated Polyester resin matrix.The percentage of sediment particles is 15% as percentage weight at average particle size is 30 μm.The percentage of strengthening phase is 12.5% ( PP Fibers + Sediment Clay Particles) from UPS resin. The specimens are prepared as two types the first is (UPS+Tainted Filter) and the second is (UPS+New Filter) then compare between the results .The tensile strength, compression strength, flexural strength, impact strength, hardness and thermal conductivity test were studied. The results showed that the hardness strength improved by to 12% percentage, tensile strength improved to 18% percentage, flexural strength improved to 17% percentage and compression strength improved to 11% percentage at tainted filter strengthening while the impact strength was decreased to 25% percentage and the fracture toughness to 15%. Also, thermal conductivity decrease by 20% percentage. We can use it in many applications such as sewer room cover, faucet handles and agricultural applications.

Cellular manufacturing is defined as a manufacturing philosophy that works based on the Groups technology principles. In Cellular manufacturing, the layout of the factory is meaning how to arrange the equipments, facilities, staff,… etc. in the factory area. A good layout leads to reduce the production cost, increase the productivity and improve the quality. This study aims to design the best layout of the machines on the shop floor of the factory. Therefore, the current paper attempt to investigate the optimum layout design in the State Company for the Mechanical Industries, which is located in Iskandaria/Iraq. The simulation by using Arena software was applied to help selecting the optimal layout design. Five different layout designs were suggested to compare: (linear single row, linear double rows, linear multi rows, L shape and U shape). However, according to use of the simulation outcomes, the linear layout, with double rows is found to be the best layout design. It showed better performance in the terms of average waiting time, average work in process time and average total time where it recorded the lowest values with 3.9317 minutes, 11.1370 minutes and 12.9597 minutes respectively.