DIYALA JOURNAL OF ENGINEERING SCIENCES

Biogas can serve as a substitute for natural fuel, but its use is associated with a number of features associated with the difference in its composition from natural gas. Landfill gas generated in the body of MSW landfills is characterized by a significant change in composition. The purpose of the work was a theoretical study of the effect of changing the composition of biogas and the coefficient of excess air on the parameters of the combustion process - gas and air consumption, combustion temperature and on the volume of combustion products. The influence of the ratio of CO2 and N2 contained in biogas on the main combustion characteristics was also evaluated. It is concluded that the combustion of biogas of variable composition, subject to ensuring the specified heat output of the furnace or boiler, does not require a change in air flow, but only a change in the flow of biogas depending on the content of methane in it. Reducing the content of methane leads to an increase in the volume of exhaust gases and a decrease in their temperature. Therefore, a decrease in the methane content in biogas can lead to a decrease in the intensity of heat exchange and a decrease in the efficiency of the unit. The ratio of CO2 and N2 practically does not affect the thermal parameters of combustion. The results of the study are necessary when designing equipment and determining the operating mode of equipment that burns biogas that is formed in natural conditions, for example, landfill gas generated at HSW landfill.

The request for housing in Ghana is great and as a result the selection of durable roofing sheets have become very significant as roofing plays a vital role in building construction. This study examines some mechanical properties of the most common locally-produced and imported roofing sheets in the housing industry in Ghana to inform decision-making when it comes to roofing. The roofing sheets chosen were One Star Galvanized Japan (G1*Jap), Galvanized Coated (GC), Aluzinc three star galvanized (AlZn3*), One Star Galvanized Indi (G1*Ind) and Aluminium (Al) due to their popularity and wide availability on the market. Samples from these were cut into specific dimensions and placed in a Tinius hydraulic Universal Testing Machine (Model 602) for testing. The results showed that AlZn3* had the highest Young’s Modulus of Elasticity of 18.21MPa, Ultimate Tensile Strength (UTS) of 50.27 MPa; Aluminium (Al) recorded the highest Percentage Elongation of 28% and Breaking Energy 7956600 MJm-2 with G1*Jap recording the least UTS of 26.6 MPa and Breaking energy of 55378 MJm-2 whiles G1*Ind showed the least Young’s Modulus of Elasticity of 7.6 MPa and Percentage Elongation of less than one percent (0.5%).These numbers lead to the conclusion that AlZn3* roofing sheet is generally the best roofing sheet. Based on this it was concluded that AlZn3* is the best roofing sheet on the Ghanaian market due to its unmatched mechanical strength.

The goal of structural design is to select member sizes that are proportional to the structural geometry in order to achieve the most cost-effective design. Steel girders were typically made of webs, flanges and a number of internal stuffeners, the main objective of this research is to develop a finite element model to study the effect of the shapes and locations of openings on the behavior of hollow flange steel plate girders. In this study, seven models were analyzed in two groups. The first group study the effect of web openings shape openings on the behavior of hollow flange steel plate girders, while the second group study the effect of web openings location on the behavior of hollow flange steel plate girders. The girders are analyzed until the final failure has occurred. The results obtained from finite element analysis showed that that the absence of opening had an important effect on the ultimate load capacity. The ultimate capacity of hollow flange steel plate girder with four squares opening decreased about 5% compared to hollow flanges steel plate girder without openings.

In this work, a couple of spur gears design was changed by two double- helical gears design with maintaining other parts in the same size approximately for a hydraulic pump of agricultural tractor. The main purpose of this attempt was to obtain a new hydraulic pump with better specifications and performance. The new elements of the pump were designed using 3D Solid Works software then the stresses analyses and CFD analyses were archived using ANSYS software. The results showed a better flow rate of the hydraulic fluid by about 17%. This reflects the success of this idea where the flow rate of the new design was much higher compared with spur gear pump. This will conclude that the new design led to improve the pump performance. Moreover, the new pump overcomes the problems that usually appear in spur gears such as noise, vibration fracture. However, this design considers one of the most difficult parts in manufacture process therefor, it was recommended to fabricate it with3D printers

There are millions of persons in this world have been suffered from land mines or other accidental events which have caused amputations. The human body feet provide stability and balance when standing and moving. Amputation of a foot highly decrease the amputee’s ability to practice common activities such as walking. The main target of a prostheses of any kind is to improve or return function to a physically disabled person. Although, the rapid developing of alternative prostheses technology, unfortunately, it is still a far from inquiring quite functional prosthetic limb replacement. The present study was focused on design and manufacturing of a two degree of freedom ankle rotation, plantar flexion- dorsiflexion in sagittal plane and inversion - eversion in frontal plain so as to mimic the normal human gait and also to reduce the pain and stress in the residual limb. Most ankle parts were formed from aluminum alloy and assembled to a carbon fiber foot laminated foot. The gait analysis was performed by the amputee user case study for both his prosthetic foot and the designed foot at the same optional ground surface conditions. The user foot angles responses were: eversion 2.60, inversion 2.60, plantar 8.70, dorsi 5.30, in contrast, the designed foot angles were: eversion 9.50, inversion 9.80, plantar 10.20, dorsi 10.40. The achieved designed maximum rolling in frontal plane was 100 inversion- eversion angle and the maximum rolling in sagittal plane were 120, 180 for plantar and dorsi flexion angle respectively.

The impact of urban infill has been an important topic within urban research. Despite the vast knowledge, however, there is a gap in reporting the effect of adding contemporary malls to Baghdad urban context; therefore, we studied two main contemporary malls built after 2003, Al-Mansour Mall in Al-Mansour district and Baghdad Mall in Harthiya district, selected for this study because of their large-scale and their contribution to the development growth of the city. The findings of this research showed they both have a strong impact on different aspects such as urban, social, economic, and the environment. The paper also highlights critical views concerning the spread of malls in Baghdad and discusses the importance of traditional suqs and the reasons of transition to the contemporary malls with suggestions for improvement. This paper contributes to the urban literature by developing a theoretical framework of urban infill indicators. Findings may have implications for future infill developments both for architecture and urban design strategies for city growth.

In most engineering designs, steel connections are usually considered as fully rigid connections or perfectly pinned connections, for simplicity of design work. In reality, this assumption is incorrect. The behaviour of the beam-column connection is in between of rigid connection and perfectly pinned connection. This type of connection is termed semi-rigid connection. This article represents a numerical analysis using finite element method of structural steel frames to investigate the effect of semi-rigid beam-column connection on the behaviour of the frame. ANSYS software was used for the finite element modelling of the frames. The beam-column connection was modelled as rotational spring with specified rotational stiffness using COMBIN14 element. The study includes investigation the effect of semi-rigid on different study cases such as: support types and number of stories. The obtained results reveal that changing the beam-column connection from rigid case to semi-rigid case with different rotational stiffness can increase the vertical and horizontal displacement of the frame with a percentage depends on the rotational stiffness of the beam-column connection. Changing the support type of the frame from fixed to pinned support or increasing the number of stories with semi-rigid connection can decrease the strength capacity of the frame. This indicates the importance of including the semi-rigid connection in the design and analysis of steel frames to obtain more realistic results.

In this study, the finite element method using ANSYS workbench 16.1 has been successfully used to predict the fatigue life, fatigue strength, and the factors of safety for the as cast AA5052 as arrow matrix and its composites: AA5052/7 wt% ZrO2, AA5052/7 wt% TiO2 and AA5052/7 wt% Al2O3. The Finite Element Analysis (FEA) model was building according to dimensions of the experimental fatigue specimen. The total number of elements was 504 elements with a total number of nodes of 2572 nodes. The numerical fatigue test was processed under static structural analysis, and it has been analyzed using fatigue tool on ANSYS, Goodman theory was used for the prediction of life. The FEM using ANSYS.16.1 workbench simulation showed a good agreement with the experimental results for all the stress life curves and the highest difference in fatigue life was 17% and the lowest was 1.4%, for ZrO2 composite, while the maximum overall average error was 2.031% for AA5052 and the lowest was 0.378%, for Al2O3 composite. The maximum difference about 4.14 % between the experimental and numerical fatigue strength at 107 cycles for the row matrix and less than for the composites, also the minimum factor of safety for the AA5052 alloy is 0.8327 and for AA5052/7 wt% ZrO2 composite is 1.0709 while for both AA5052/7wt%TiO2 and AA5052/7 wt% Al2O3 composites are 1.0707 at specific design life.

Energy harvesting is a top research topic right now, as the entire world seeks green energy as an alternative source. The power (voltage) extracted from the piezoelectric system was optimized. Several factors influence the creation of electric energy when a load is applied to the sensors, either directly (strain) or via ambient vibration. These variables include the kind of Piezoelectric elements, the frequency of applied stress, the distance from the rotating axis, stiffness, and inserting a chamber beneath the piezoelectric elements .The most affected factor was increasing the distance from the rotating axis since the maximum voltage was 7.02 volt at 106 r/m and the distance is 25 mm. when connecting Piezoelectric elements with cavities below it harvesting a voltage of Vmax equal 26.3 volt at 106 r/m and distance of 25mm. Increasing the stiffness of spring from 360.5 N/m to 522.4 N/m results in increased energy harvesting. Increasing the Piezoelectric elements diameter from 35 mm to 35mm with cavity under it has a significant effect on the gathered voltage

Columns are one of the important structural members of engineering buildings. The impairment of reinforced concrete columns is one of the important problems affecting most structures, therefore the confinement of columns by fiber-reinforced polymers (FRP) is necessary to improve its behavior such as its load capacity, compressive strength, and ductility. The FRP used in the confinement is modern and wide application composite material in the field of civil engineering, which is pasted by epoxy. The fast impairment of epoxy at high temperatures leads to its replacement with an effective adhesive: geopolymers. This study presents the test result of an experimental investigation on confinement of six square RC columns with dimension (100*100*600mm) with geopolymer jacket under axial load conditions. The parameter considered is the jacketing material used (carbon fiber, plastic mesh, steel wire mesh, jute fiber, glass fiber mesh). Results of the test showed that confinement could improve the stiffness of the column by using a different type of material. The confinement with a carbon fiber reinforced geopolymers jackets can enhance the strength of the column after applying axial loading and improvement the performance of columns, but it is expensive. Where the increase in the load improvement and deformation capacity was (1.59 and 1.97), respectively, and the most effective jacket material in terms of economic cost and best performance in confinement operation consisted of (plastic mesh and steel wire mesh) compared to other types of material, with load enhancement by (1.41 and 1.27) and deformation capacity by (1.86 and 1.50), respectively compared with unconfined RC columns. Finally, the confinement by a different type of fiber-reinforced geopolymer adhesive is the most effective and used in the repair and rehabilitation of RC in the area with high-temperature climates.

This research focuses on the hardness of gray cast iron. Hardness is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. The machinability cannot set a specific definition. However, several indicators and directories give a clear image, the most important of which is the factors that affect the machinability of gray cast iron according to the metallurgies and the metal cutting and cutting conditions. The main goal of this research is to improve the hardness of gray cast iron. Many experiments on several samples to get different results and then compare these results to get the best which is the goal of the research. The conclusions through the practical side of this research are the different values of hardness through the different hardening processes. As the hardening processes gave a sample of grey cast iron a hardness value that differs in each type of hardening. The notes through the graph that the hardness reaches its peak in the traditional hardening, where its value is (370.6), followed by the laser hardening process, which reaches (321.6) The amount of increase between the hardness of the laser and the traditional hardness takes the value of (15.24 %) The work on samples in the form of aggregates, and each group will be treated in a specific way and then subject to tests.

This paper presents an exploration of choosing the optimum density for concrete that achieves the best structural performance for two-way slabs made of concrete with fine aggregate in different proportions less than the ratio used in ordinary concrete to produce different densities, by taking advantage of the idea of fine aggregate concrete which considers as light-weight concrete to achieve lighter concrete with higher structural endurance. The experimental program includes constructing and testing five slabs, four of them made of concrete with different fine aggregate radios 75%, 50%, 25%, and 0% to get different densities (2207, 1792, 1536, 1310 kg/m3) as well as another slab made of normal concrete used as a reference slab with a density of 2414 kg/m3. The outcomes reveal that decreasing the density of the slab from 2414 kg/m3 to 1310 kg/m3 by reduction fine aggregate in concrete from 100% to 0% respectively has more effect on the first crack load than that on the ultimate load of two-way slabs as the first crack load decreases with percentages 16.7%, 33.3%, 38.9%, and 61.1% the while the ultimate load decreases with percentages 7.3%, 21.9%, 46.3%, and 56.1%, respectively as compared to the reference (normal wight concrete slab). Also, decreasing the density of the slab made the cracks form and spread quickly and the slab failure tends towards the brittleness, and the cracks diffused and grew faster and wider.