EFFECT OF INLET AIR TEMPERATURE ON COMBUSTION, PERFORMANCE AND EMISSIONS OF GASOLINE DIRECT INJECTION (GDI) ENGINE FUELLED BY LPG FUEL

In the present work, the direct-injection petrol engine (GDI) combustion, emissions and performance at different engine speeds (1500, 2000, 2500 and 3000 rpm) with a constant throttle position have been studied. The fuel considered in this work is liquid petroleum gas (LPG) and gasoline. The software adopted in all simulations by the AVL BOOST 2016. A Hyundai 2.0 liter, 16 valves and 4 cylinders engine with a compression ratio 17.5:1 is used. The effect of several inlet air temperatures (0, 10, 20, 30, 40 and 50 oC) on the engine performance, combustion and emissions are also studied. The results show that the increase in the inlet air temperature leading to increase the peak fire temperature, brake specific fuel consumption (BSFC) and nitrogen oxide (NOx). However, this process results in a reduction in the peak fire pressure, combustion period (duration), brake power and brake torque. The maximum fire temperature and maximum specific fuel consumption can be achieved when the engine speed is 3000 rpm and the inlet air temperature is 50 ºC.

BENDING PROPERTIES OF A FUNCTIONALLY GRADED POLYMERIC COMPOSITE REINFORCED WITH A HYBRID NANOMATERIAL

In this paper, functionally graded polymer hybrid nanocomposites have been produced by silica (SiO2) nanoparticles and alumina (Al2O3) nanoparticles distributed in a matrix of epoxy during the ultra-sonication via hand lay-up method. The variation in nanoparticles volume fraction (Vf.) has been given in the thickness direction for reaching the gradation. Each layer has a thickness of 1.2 mm through various concentrations of nanoparticles and is sequentially cast in acrylic moulds to fabricate the graded composite sheet with a 6 mm thickness. To fabricate the functionally graded layers, various concentrations of different nanoparticles (1.5% SiO2, 1% SiO2, epoxy, 2% Al2O3 and 3% Al2O3) have been used for tensile and compressive testing each isotropic layer of functionally graded material (FGM). The mechanical property that was studied for pure epoxy, isotropic and FGM was the flexural resistance. The flexural properties of FGM, isotropic nanocomposite (1% SiO2 + 2% Al2O3) and pristine epoxy, for evaluating their mechanical properties, including flexural stress-strain criteria and flexural Young's modulus, were determined via a Three-point bending test, with loading from the side of silica and alumina for the hybrid-FGM and at one side for the isotropic hybrid nanocomposite and pristine epoxy. The mechanical properties (tensile and compression) and the density of every layer were obtained for the epoxy resin and nanocomposites. They can benefit from the Finite Element Analysis (FEA) of the Three-point bending test via the Design Modeler (ANSYS workbench). The results of experiments were confirmed via building a detailed 3D FE model. Also, the advanced deformation results from the FE model were found in good agreement with the experimental outcomes.

USING OF CoCr ALLOYS IN BIOMEDICAL APPLICATIONS ( REVIEW)

Metals are used extensively in biomedical applications due to their mechanical strength, corrosion resistance, and biocompatibility. There are many types of metals and alloys used in this application ( stainless steel, Ti and Ti alloys, CoCr, dental amalgam, etc). This review focus on CoCr alloys which have excellent corrosion resistance and mechanical properties which make them the best choice for many types of surgical implants. There are many alloying elements used to improve the properties of CoCr alloy such as ( Zr, In, Ta, etc ) has been reviewed.

INVALIDITY OF ISOTHERMAL ANALYSIS IN ESTIMATING THE THERMAL PERFORMANCE OF STIRLING ENGINE AND CRYOCOOLER

The Stirling engine is an external heat engine, which is considered as the best option for extracting work from concentrated solar power applications. The most prominent characteristics of the engine are low noise, vibration, and emissions besides reflexivity of usage with any kind of heat source such as solar, biomass, industrial heat, etc. In the present paper, the STE-1008 gamma-type Stirling engine had been analyzed by using an isothermal model to demonstrate the failure of the model in analyzing the STE-1008 considering it firstly as an engine and secondly as a cryocooler. The energy equation had been used to demonstrate the disability of the isothermal model in achieving a successful thermal analysis for engine performance. In addition, a MATLAB code had been developed to check the credibility of the isothermal model in the estimation of the engine thermal parameters. The findings of the isothermal analysis revealed that the heat exchangers are unnecessary. But, in reality; all the necessary heat transfer occur within the heat exchangers rather than in the working space boundaries. Therefore, that is invalid conclusion. However, Schmidt's theory is capable of capturing the essential engine features superbly. In particular, it is capable of capturing the fundamental interplay between the mechanically restricted movement of the engine components as well as the thermodynamic cycle which is obtained from this theory.

EXPERIMENTAL INVESTIGATION ON THE EFFECT OF ADDING CYCLOHEXANONE TO GASOLINE IN SI ENGINE EMISSIONS AND PERFORMANCE

The aim of the present work is to investigate the influence of adding some ketone compounds on the performance, emissions, heat balance and exhaust gas temperature of spark ignition engine. The ketone used in this study is cyclohexanone (C6H10O). This ketone has been added to the base fuel (gasoline) with three concentration ranges (3, 6 and 9%) respectively. All experimental tests were carried out on gasoline engine type (Nissan QG18DE), four cylinders, 4-stroke, direct injection, with compression ratio (9.5:1). The acquired results showed that adding of ketones affect the physical properties of gasoline. Where the density changed from (710 kg/m3) for net gasoline to (740.8 kg/m3) for cyclohexanone at adding ratio of (9%). The octane number also increased from (86) for pure gasoline to (97.7) for fuel with 9% cyclohexanone. The calorific value will be decrease from (43000 kJ/kg) for gasoline to (42077.5) for cyclohexanone at adding ratio of (9%). The addition of ketones improves the emissions characteristic of engine. The best reduction of (UHC, CO_2, CO and NOx) was (49.04, 22.43, 35.02 and 42.14%) recorded by cyclohexanone addition at ratio of (9%). In the case of performance, all parameters of performance improved by adding ketones. The brake specific fuel consumption reduced by (8.9%) by adding (9%) of cyclohexanone which recorded as the best reduction through all types. The best increment of brake power, brake thermal efficiency, brake mean effective pressure and volumetric efficiency was (17.3, 8.98, 17.25 and 12.7%) is achieved by adding (9%) of cyclohexanone. Also, the exhaust gas temperature will be increase by adding ketones. The percentage increasing of exhaust gas temperature was (28.31%) recorded by cyclohexanone addition at ratio of (9%). In the case of heat balance, the best increment of total heat internal energy was (6.59) at (9%) of cyclohexanone.

THE EFFECT OF BEND ANGLE ON THE EVAPORATIVE COOLING OF AIR FLOW THROUGH BENT DUCT

One remediation to output power drop of a gas turbine generating units during hot climates is reducing compressor inlet air temperature using fogging technique incorporating water injection into the airstream. The inlet air ductworks often include a bend or curved duct before the compressor comprising the secondary flow utilized to enhance the mixing between air and water droplets. This study investigates the effect of changing the bend angle on the resultant evaporative cooling of steadily flowing airstream. The experiments were conducted with an average air velocity range from (2.5 to 5 m/s) through (50) cm square duct. The study considered three bend angles of (45°, 90° and 135°) along with three sets of nozzle tilt angles of (- 45o, 0° and 45° ) to the axial flow direction. The results reveal that best evaporative cooling was achieved at a bend angle of (135°) when the water is axially injected, i.e., at (0o) to flow direction. These conditions were obtained at the velocity of (2.5 m/s), giving enough residence time for the injected droplets to evaporate and cool the airstream.

THE INFLUENCE OF STIRRER ON THE DRYING OF WHEAT PARTICLES IN A FLUIDIZED BED AT LOW AIR VELOCITY

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.

INVESTIGATION OF COMPOSITE METAL MATRIX REINFORCED WITH CARBON NANOTUBES

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%.

CHEMICAL DEPOLYMERIZATION OF WASTE PLASTICS IN BUBBLE COLIUMN REACTOR FOR BLENDED FABRICATION

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.

CORROSION INHIBITION OF CARBON STEEL IN HYDROCHLORIC ACID

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