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Aims and Scope
Editorial Board

1. A suggested analytical solution of oblique crack effect on the beam vibration

Muhannad Al-Waily

Mechanical Engineering department, Faculty of Engineering, Al-Kufa University, Ministry of Higher Education & Scientific Research, Iraq.

Abstract: In this research development the derivation of general equation of motion for beam with crack effect presented in paper [1], to derivation the general equation of motion of beam with oblique crack effect. The derivation of equation of motion of beam included suggested analytical solution for effect of oblique in crack on the natural frequency of beam with added the effect oblique of crack in stiffness (EI) beam with calculated the equivalent stiffness, (EI), for a rectangular beam to involve an exponential function with depth, location and ordination of oblique crack effect, with solution of assuming equivalent stiffness beam (EI) by using of Fourier series method. The natural frequency of a cracked beam with simply supported beam is investigated analytically, with solution of general equation of motion of beam with oblique crack effect, and numerically by finite element method, with using of ANSYS program ver. 14, for different crack depth, location and crack orientation effect and the results are compared. The same beam materials studied in paper, [1], are study in this research as, low carbon steel, Alloys Aluminum, and Bronze materials with different beam length, depth and crack orientation. A comparison made between analytical results from theoretical solution of general equation of motion of beam with oblique crack effect with numerical solution by finite element method with using ANSYS results, where the biggest error percentage is about (1.8 %). The results of natural frequency of beam shows that the natural frequency of beam increasing with increasing the crack orientation, the effect of crack orientation decreasing with increase the orientation of crack.

Volume 6, Issue 3, 2015, pp.227-246.

2. Validation of chemical-looping with oxygen uncoupling (CLOU) using Cu-based oxygen carrier and comparative study of Cu, Mn and Co based oxygen carriers using ASPEN plus

Xiao Zhang, Subhodeep Banerjee, Ramesh K. Agarwal

Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, 1 Brookings Drive, St. Louis, MO 63130, USA.

Abstract: The chemical-looping with oxygen uncoupling (CLOU) has been demonstrated to be an effective technological pathway for high-efficiency low-cost carbon dioxide capture when particulate coal serves as the fuel. In this paper, complete process-level modeling of CLOU process conducted in ASPEN Plus is presented. The heat content of fuel and air reactors and air/flue gas heat exchangers is carefully examined. It is shown that the established model provides results which are in excellent agreement with the experiments for the overall power output of the CLOU process. Finally the effect of varying the air flow rate and three different types of coal as the solid fuel on energy output is investigated, and the performance of three - Copper (Cu), Manganese (Mn) and Cobalt (Co) based oxygen carriers in CLOU process is compared. It is shown that there exists an optimal air flow rate to obtain the maximum power output for a given coal feeding rate and coal type. The effect of three different oxygen carriers on energy output is also investigated using the optimal air flow rate. Among the three oxygen carriers - CuO, Mn2O3, and Co3O4; Mn2O3 shows the best performance on power output. The results presented in this paper can be used to estimate the amount of various quantities such as the air flow rate and oxygen carrier (and its type) required to achieve near optimal energy output from a CLOU process based power plant.

3. Temperature field of steel plate cooling process after plate rolling

Huijun Feng^1,2,3, Lingen Chen^1,2,3, Fengrui Sun^1,2,3

1 Institute of Thermal Science and Power Engineering, Naval University of Engineering, Wuhan, 430033, China.

2 Military Key Laboratory for Naval Ship Power Engineering, Naval University of Engineering, Wuhan, 430033, China.

3 College of Power Engineering, Naval University of Engineering, Wuhan 430033, China.

Abstract: Based on numerical calculation with Matlab, the study on cooling process after plate rolling is carried out, and the temperature field distribution of the plate varying with the time is obtained. The effects of the plate thickness, final rolling temperature, cooling water temperature, average flow rate of the cooling water, carbon content of the plate and cooling method on the plate surface and central temperatures as well as final cooling temperature are discussed. For the same cooling time, the plate surface and central temperatures as well as their temperature difference increase; with the decrease in rolling temperature and the increase in average flow rate of the cooling water, the plate surface and central temperatures decrease. Compared with the single water cooling process, the temperature difference between the plate centre and surface based on intermittent cooling is lower. In this case, the temperature uniformity of the plate is better, and the corresponding thermal stress is lower. The fitting equation of the final cooling temperature with respect to plate thickness, final rolling temperature, cooling water temperature and average flow rate of the cooling water is obtained.

4. Estimating the annual range of global illuminance on a vertical south facing building facade

Tijo Joseph, Animesh Dutta

School of Engineering, University of Guelph, Guelph, Ontario, Canada.

Abstract: Towards assessing the daylighting potential for a campus building and in consideration of the recommended strategy of maximizing window exposure on south-facing walls in northern latitudes, the range of global illuminance on a south facing vertical surface at the building location was estimated over an annum, under both clear and cloudy sky conditions, using a calculation methodology proposed by the Illuminating Engineering Society of North America. The illuminance is observed to be a variable over the day with the daily variation estimated to range as high as 35KLx, over the year and under different sky conditions. Overall, it is estimated that the dynamic variation of global illuminance on a south facing façade,specific to the study location, ranges from 14KLx to 100Klx.

5. Free vibration analysis of stiffened cylinder shell

Hatem H. Obied, Mahdi M. S. Shareef

University of Babylon, College of Engineering, Mechanical Engineering Department, Babylon, Iraq.

Abstract: In this paper, the effect of different types of stiffeners on the cylindrical shell structure is investigated. The dynamic properties (natural frequencies and damping ratio) were computed for each finite element models. Finite element models for the different steel cylindrical stiffened shell have been created by considering helix angle, numbers, locations and height of stiffeners with a constant mass which is (4 kg), and a cantilever supported structures are used. An experimental test has been done to check the validity of the stiffened shell model. The results obtained are the natural frequency and damping ratio. A comparison between the natural frequency and finite element result is made with an error (18.43%) is found. Modal analysis is performed to each finite element models to extract the values of the natural frequencies. The model of (helix angle = 67.5^o, height = 3.125cm, internal and eight stiffeners) have the highest value of the natural frequency when compared with the other models. Finally, a comparison between experimental work of M. Bagheri and A.A. Jafari [1] and numerical part of the current paper has been occurred with a small percentage error between them.

6. A site-specific design of a fixed-pitch fixed-speed wind turbine blade with multiple airfoils as design variable

Arturo Del Valle-Carrasco¹, Delia J. Valles-Rosales¹, Luis C. Mendez², Alejandro Alvarado-Iniesta²

1 New Mexico State University, Department of Industrial Engineering, MSC 4230/ECIII, PO Box 30001, Las Cruces NM, 88003-8001, USA.

2 Autonomous University of Ciudad Juarez, Department of Industrial Engineering and Manufacturing Av. Del Charro, 450 Nte, Ciudad Juarez, Chihuahua, 32315, Mexico.

Abstract: This study seeks to optimize a fixed-pitch fixed speed (FPFS) wind turbine blade’s performance using the chord, twist and the use of 3 different airfoils with varying relative thickness as design variables for the maximization of the Annual Energy Production for the wind profile of Roswell NM. A baseline design of the blade starts with a replica of the Phase VI blade utilized in a NASA-Ames experiment and a Matlab script utilizes the Blade Element Momentum Theory (BEM) for the aerodynamic analysis. The SQP method for Local Search are used to exploit the model utilizing the Phase VI design as a starting point which contains the S809 airfoil with a 0.21 relative thickness for the complete blade. Optimization results reduced the relative thickness of the airfoils to 0.17 and an increase of 36% in energy production was observed using this method.

7. Indoor tests on the effect of wind speed on still performance

Abdul Jabbar N. Khalifa, Marwa AW. Ali

Al-Nahrain University, College of Engineering, Mechanical Engineering Department, Jadiriya, P.O. Box 64040, Baghdad, Iraq.

Abstract: Wind speed is an important parameter that affects the productivity and efficiency of solar stills. The literature shows conflicting opinions about the effect of wind speed on the total yield of fresh water from solar stills. One reason behind such discrepancy could be attributed to the uncontrolled effect of some of the meteorological parameters. This study reports an investigation on the effect of wind speed on the performance of basin type stills carried out indoor using a fan to generate airflow analogous to the outdoor wind and heaters to provide uniform heat flux to the basin. The tests were conducted for four different wind speeds of 1.14, 2.06, 2.92 and 4.01 m/s in addition to tests with stationary air. It was found that increasing wind speed will definitely increase the yield of solar stills and high wind speeds may give less improvement in productivity than moderate wind speeds.

8. Anaerobic digestion of pig manure and glycerol from biodiesel production

Pakamas Chetpattananondh1, Sumate Chaiprapat2, Chaisri Suksaroj2

1 Department of Chemical Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand.

2 Department of Civil Engineering, Faculty of Engineering, Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand.

Abstract: Increasing biodiesel production causes a surplus of glycerol. This work aims to investigate the crude glycerol pretreatment method and then apply the glycerol as a co-substrate with pig manure for anaerobic digestion. The optimum crude glycerol pretreatment method was acidification with 6% of H₂SO₄ that highest glycerol recovery was obtained with lowest cost. Co-digestions of glycerol and pig manure enhanced biogas and methane productions compared with mono-digestions. Biogas and methane productions in semi-continuous digestions were highly effected by OLR. The optimum OLR was 3.06 kg SCOD/m³ that biogas production was maintained at 3 L/d with methane composition of 72% and SCOD removal higher than 80%.