Journal of Engineering

Surface modeling utilizing Bezier technique is one of the more important tools in computer-aided geometric design (CAD). The aim of this work is to design and implement multi-patches Bezier free-form surface. The technique has an effective contribution in technology domains and in ships, aircrafts, and cars industry, moreover for its wide utilization in making the molds. This work includes the synthesis of these patches in a method that allows the participation of these control points for the merge of the patches, and the confluence of patches at similar degree sides due to degree variation per patch. The model has been implemented to represent the surface. The interior data of the desired surfaces designed by MATLAB software have been transformed to UG-NX8 software to get the machining process simulation and G-code programs for the model, as well as a virtual machining process has been simulated to show the machining pitfalls, using CIMCO edit software. The sample has been machined using a 3-axis vertical CNC machine. Finally, the sample has been measured using CMM inspection and it’s found that the average error is 0.144 mm.

This research focuses on finding more effective polymers to enhance the rheological properties of water-based muds. Experiments were conducted using different types of mud and substances, including Polyacrylamide, Xanthan gum, and Carboxyl Methyl Cellulose (CMC). The study examined the effects of adding polymers to red bentonite mud, Iraqi bentonite mud, and polymer mud. The results showed that adding polymers to Iraqi bentonite blank enhanced mud properties, with CMC providing the highest plastic viscosity and gel strength, and Xanthan giving the highest yield point and gel strength. For red bentonite mud, Polyacrylamide had the highest shear stress and yield point, while Xanthan had the highest effect on plastic viscosity. All polymers reduced filtration loss, but the polymer solution mud failed to suspend barite, making it unsuitable as a drilling fluid despite its good rheological properties.

This study aimed to investigate the feasibility of treating actual potato chips processing wastewater in a continuously operated dual chambers microbial fuel cell (MFC) inoculated with anaerobic sludge. The results demonstrated significant removal of COD and suspended solids of more than 99% associated with relatively high generation of current and power densities of 612.5 mW/m³ and 1750 mA/m³, respectively, at 100 Ω external resistance.

This study investigates the possibility of using waste plastic from expired lead-acid batteries to produce lightweight concrete. Different percentages of lead-acid battery plastic were used in the production of lightweight concrete. The replacements were 70%, 80%, and 100% by volume of the fine and coarse aggregate. Results demonstrated a reduction of approximately 23.6% to 35% in the wet density when replacing 70% to 100% of the natural aggregate with lead-acid battery plastic. The compressive strength decreased slightly with the increase in plastic content at different curing ages of 7, 28, 60, 90, and 120 days. The lowest value of compressive strength was 20.7 MPa for 100% waste plastic at 120 days test age. The results also revealed that the thermal conductivity decreased with the addition of waste plastic compared to plain concrete, and this property decreased further with an increase in waste proportion.

The applications of Multilevel Converter (MLC) are increasing due to the high demand for clean power, especially since these converters are compatible with renewable energy sources. This paper analyzes and simulates a nine-level converter in three modes of implementation: Diode Clamped-MLC (DC-MLC), Capacitor Clamped-MLC (CC-MLC), and Modular Structured-MLC (MS-MLC). Various types of Multicarrier Modulation Techniques (MMTs) (Level shifted (LS) and Phase shifted (PS)) are used for operating the proposed nine-level MLCs. Matlab/Simulink environment is used for the simulation, extraction, and analysis of the results. Finally, a comparison is made between the results for all topologies implemented regarding the criteria of the output voltage waveforms harmonic distortion factor, the number of necessitated power components, and the complexity of each circuit. Based on simulation results, the MS-MLC is finer compared to the other types of MLCs. It is also observed that the MLCs (with three types) using the Phase Opposition Disposition (POD) technique perform better in terms of achieving greater fundamental output voltage and lower THD% compared to other techniques.

In this paper, different channel coding and interleaving schemes in DS/CDMA system over multipath fading channel were used. Two types of serially concatenated coding were presented. The first one composed of Reed-Solomon as outer code, convolutional code as inner code and the interleaver between the outer and inner codes and the second consist of convolutional code as outer code, interleaved in the middle and differential code as an inner code. Bit error rate performance of different schemes in multipath fading channel was analyzed and compared. Rack receiver was used in DS/CDMA receiver to combine multipath components in order to enhance the signal to noise ratio at the receiver.

Self-curing is the potential of lightweight aggregate to absorb a great amount of water during mixing, which can then move to the paste during the hydration process. This study investigates the effect of brick dust recovered from construction sites on the properties of mortar cured in three different conditions. Mortar in this study was produced using brick dust (BD) as a cement additive with (2, 4, 6, and 8) % by weight of cement, and as a cement replacement with (1, 2, 3, and 4) % by weight of cement. The results showed that compressive strength and modulus of rupture decreased when BD was used as a cement additive and replacement. However, these properties were higher for mortars cured in air conditions than those cured in water and partially water curing. Water absorption increased with the increase of BD when used as a cement additive and replacement. The study indicated that BD could be used as a self-curing agent and could replace cement at specific ratios, achieving economic benefits and reducing environmental pollution.

In this paper, the variable structure control theory is utilized to derive a discontinuous controller for the magnetic levitation system. The magnetic levitation system model is considered uncertain, subjected to uncertainty in system parameters, and is open-loop unstable and strongly nonlinear. The proposed variable structure control for the magnetic levitation system is proved, and the area of attraction is determined. Additionally, the chattering, induced due to the discontinuity in control law, is attenuated by using a non-smooth approximation. With this approximation, the resulting controller is a continuous variable structure controller with a determined steady-state error according to the selected control parameters. Finally, the ability and effectiveness of the proposed continuous variable structure controller for the magnetic levitation system are verified via numerical simulations. When the state is initiated inside the area of attraction, the results show that the ball position can be directed to follow various desired positions, with a steady-state error not exceeding a certain limit.

The role of green areas lies in being one of the systems that plays a vital role in achieving the environmental dimension besides the socio-cultural body and the economic dimension in the hidden value of ecosystem services. However, many developing countries are characterized by a state of low community environmental awareness, which coincides with the basic need for land for housing and other uses, taking precedence over nature protection strategies. In the absence of clear planning and long-term planning strategies, this has led to abuses and violations of urban land use. In Iraq, the situation became more apparent due to the political, security, and social conditions that followed the year 2003. Hence, the research problem of the phenomenon of excesses on the use of green land in Iraqi cities in general and Baghdad in particular, which led to many adverse effects. The aim of the research is to explore the importance of green spaces and the value of biological diversity, and to detect the effects of the phenomenon of continuous abuses. The study followed an analytical descriptive approach to data collection and vocabulary extraction in relation to green areas, levels, and hierarchies, and the extraction of theoretical indicators for the effects of the changes that occurred on them. They were tested in practice in neighborhoods no. 338, 336 in the city of Baghdad, in the light of a field analysis and survey. The research found a decline in the area of green areas as their ratios do not meet the local and global standards required, especially with the increasing urban and population density over the past decade. In addition to what the neighborhoods suffer from urban chaos and a severe shortage of infrastructure services. Greenness and its functional and visual role in beautifying the urban landscape can be observed only in the remaining agricultural use, in nurseries and orchards, which are private property that does not include the general population in the use of its functions.

This research is concerned with studying the characteristics of Sustainable Architecture and Green Architecture. It aims to differentiate between the two concepts, which are often overlapping for research centers, individuals, and relevant organizations. The study explores their characteristics and seeks to clearly differentiate between the two terms, particularly in architecture. The research problem focuses on the lack of clear differentiation between sustainable and green architectures, causing confusion in dealing with building projects. The research hypothesis suggests that environmental and architectural indicators can form a mechanism to differentiate between sustainable architecture and green architecture. This mechanism depends on several elements that form the hypothesis testing tool, which will become a method to verify the hypothesis and achieve the research goal of forming a theoretical framework to differentiate between sustainable and green architectures. The theoretical framework is applied in two environmentally friendly architectural projects (case studies) to reveal the availability of the features.