KUFA JOURNAL OF ENGINEERING

FSSW is a solid state joining method gained its significance as an alternate welding technique in the in electrical, electronic and automobile industries that used FSW welding. FSSW can be used to welding dissimilar joints of material with variation in metallurgical and mechanical characteristics. In this paper, dissimilar welding joints of aluminum alloys (5052) and pure copper (10100) with a thickness of 1.67 mm were welded by FSSW. The variation of rotational speed, dwell time and filler content have been used. The welding joints has been examined by tensile shear test. The scanning electron microscope SEM and X-ray diffraction are used to investigate the hook and intermixing layer characteristics. It was found the best welding condition is (1400 rpm) and (30 sec) which the joint is possess the tensile shear force (3340 N). Adding ZnO filler led to increase the thickness of the copper hook, and expanding the stir zone (weld width bond). Joints with V2-ZnO have highest thickness of intermixing layer (IM), length of weld width bond and best tensile shear force (4300 N).

Computer simulation can be of high importance to analysis geometry regarding the signalized roundabouts and intersections that are related to systems of urban streets. The major goal of the presented research is analyzing geometry as well as the intersection classification that is related to traffic flow, as well as enhancing the capacity related to intersections for road networks, also relieving city’s congestions. Data on number of vehicles passing through Mudaffar roundabout have been recorded through the author of the presented study from seven in the morning to three after noon for 4 days. Sidra software was adopted to analyzed the data. The results have indicated that the level of service (LOS) regarding the present conditions in the discussed roundabout has been F, and with average delay (303.6 sec/veh). There are two proposals will be used to the developing of the roundabout. The best results indicated that the LOS for present condition of Mudaffar roundabout is C with (26.4 sec/veh) of average delay.

The paper presents an experimental determination of indoor conditions for human thermal comfort for four different structural positions in Ilorin, Kwara State, Nigeria. The Fanger\'s model was used to determine the optimum productivity level of occupants of the location under investigation. Experimental results and heat balance equation were coupled to determine the heat loss due to regulatory sweating in the zone. The results show the relationship between structural positions, skin temperature and ambient temperature of the enclosed space. For thermal comfortability, the expected indoor conditions for people sitting relaxed in their parlours, offices, and students receiving lectures should be 22°C and a relative humidity of 59.6% while for offices where documentations and businesses are done in seated and typing structural positions, a temperature of 21°C with a relative humidity of 59.3% are required for optimum productivity.

Previously, some authors proposed the innovative Taguchi–ABC and Taguchi–Pareto optimization tools to concurrently optimize and prioritize processes. In this paper, the models were used to optimize the electrical discharge machining (EDM) process parameters of AA6061/10%Al2O3 AMMC, validated with published data. Besides, the analytical hierarchy process (AHP) was used to determine the weight of factors. The Taguchi–Pareto 80/20 method utilizes the smaller-the-better quality attribute and a complimentary effort of the analysis of variance. The Taguchi-ABC uses the classified A, B and C schemes to prioritize the parameters. The AHP ranks the system as sub-problems of the top-level objective hierarchy followed by lower-level sub-criteria and bottom level variables. The results show the decreasing order of factors (pulse-on-time > peak current > duty factor) for Taguchi analysis and Taguchi-Pareto. The later yielded the optimal parametric setting of A1B2C2, indicating peak current of 6 amps, pulse-on-time of zero and duty factor of 0.6. The Taguchi-ABC reduced to Taguchi AB (i.e. optimal parametric setting as A1 B2) whereby the C (duty factor) yielded lower delta value than B (pulse-on-time). The AHP offered a conflicting result with duty factor having the largest criteria weight and the order of the weights of the factors is duty factor > pulse-on-time > peak current. The consistency ratio was 0.07 > 0.1. The results would aid EDM process engineers to effectively manage the EDM process.

The use of night-time lighting is an irreplaceable technique in modern urban societies. On the other hand, its excessive use is accompanied by undesirable effects on humans and nature, as well as on all living beings. This has been declared in the last two decades. Nowadays, light pollution is getting increasing attention all over the world, particularly in developed countries, as most of the global researches have proven that there is a direct link between serious health problems and the increase in the levels of light intensity that people are exposed to. However, to minimize the use of exceeding lighting, some countries such as South Korea and many international organizations concerned with light pollution such as CIE (Commission Internationale de l’Eclairage) have developed specifications and determinants to minimize light pollution. Furthermore, these countries have enacted laws and legislations that regulate and limit artificial lighting use. Whereas in other countries, such as Iraq, the issue of light pollution has not given enough attention from researchers or officials and there have been no specifications that limit this widespread phenomenon. In this study, a field survey was performed that included many famous commercial and main streets as well as some external roads that link Al-Najaf city with other cities in Iraq. Moreover, this investigation included measuring the intensity of lighting in many significant squares in Al-Najaf city. This study concluded out there is clear and tangible light pollution and exceeds determinants many times in most streets and roads. In Al-Sadiq Street, for example (the main street in the old city), light pollution was 16.78 times greater than the allowable limit. This is the highest value that exceeds the standard limits for a survey of the selected streets in Al-Najaf city. As for the city squares, they were all higher than the permitted limit, whether during pre-curfew or postcurfew times. In this respect, the light pollution in “Thworat al-Ishreen Square” exceeded by 48.96 times and 233.8 times the official standard of (CIE) recommendations during the period of pre-curfew and post-curfew respectively. This indicates a lack of environmental awareness in reducing unnecessary lighting as well as the absence of legislation and laws that limit the use of lighting, mainly after midnight, and that is entirely different the way the developed countries have handled the adverse effects of light pollution.