Journal of Engineering

This paper discusses usingH2 and H∞ robust control approaches for designing control systems. These approaches are applied to elementary control system designs, and their respective implementation and pros and cons are introduced. The H∞ control synthesis mainly enforces closed-loop stability,covering some physical constraints and limitations. While noise rejection and disturbance attenuation aremore naturally expressed in performance optimization, which can representthe H2controlsynthesis problem. The paper also applies these two methodologies to multi-plant systems to study the stability and performance of the designed controllers. Simulation results show that the H2 controller tracks a desirableclosed-loop performance, while the H∞ controller guarantees robust stability for the closed-loop system. The validation of the techniques is demonstrated through the robustand performancegamma index, where the H∞ controller achieved a robust gamma index of 0.8591, indicating good robustness and the H2 controller achieved a performance gamma index of 2.1972, indicating a desirableperformance. The robust control toolbox of MATLAB is used for simulation purposes. Overall, the paper shows that selectinga suitable, robust control strategy is crucial for designing effective control systems, and the H2 and H∞ robust control approaches are viable options for achieving this goal.

This research aims to create lightweight concrete mixtures containing waste from local sources, such as expanded polystyrene (EPS) beads and waste plastic fibers (WPFs), all are cheap or free in the Republic of Iraq and without charge. The modern, rigid, and mechanical properties of LWC were investigated, and the results were evaluated. Three mixtures were made, each with different proportions of plastic fibers (0.4%, 0.8%, 1.2%), in addition to a lightweight concrete mixture containing steak fibers (0.4%, 0.8%, 1.2%), in addition to a lightweight concrete mixture. It contains 20% EPS. The study found that the LWC caused by the addition of WPFs reduced the density (lightweight) of the concrete mixtures because EPS tends to form more blocks, absorb water, and dry the mixture. While the increase in WPF content increased in compressive strength, as the compressive strength of the concrete mix containing (EPS) was only 13.6 MPa, the compressive strength increased to 17.6 MPa when WPFs were added. The addition of plastic also increased the bending resistance, where the bending resistance of the concrete mix containing (EPS) was only 2.26 MPa and increased to 2.66 MPa when (WPFs) were added.

Non-biodegradability of rubber tires contributes to pollution and fire hazards in the natural environment. In this study, the flexural behavior of the Rubberized Reactive Powder Concrete (RRPC) beams that contained various proportions and sizes of scrap tire rubber was investigated and compared to the flexural behavior of the regular RPC. Fresh properties, hardened properties, load-deflection relation, first crack load, ultimate load, and crack width are studied and analyzed. Mixes were made using micro steel fiber of the straight type, and they had an aspect ratio of 65. Thirteen beams were tested under two loading points (Repeated loading) with small-scale beams (1100 mm, 150 mm, 100 mm) size.
The fine aggregate is replaced by 5, 10, and 15%, respectively, with crumb rubber. While replacement of silica fume was 10, 20, 30, and 50%, respectively, with very fine rubber. Also, chip rubber was added to the mixture as coarse aggregate with 5, 10, and 15%. Five tested beams were chosen as case studies to analyze and compare the results of the ABAQUS software with the experimental results. The results showed that the flexural behavior of RRPC beams that contains rubber was acceptable when compared with the flexural behavior of the RPC beam (depending on load-carrying capacity). The crack width was decreased by including waste rubber and steel fibers. There is a satisfactory agreement between the results of the numerical analysis and the results of the experimental testing. Slight ultimate load differences are targeted between the effects of the monotonic loading and the repeated loading.

Nanoparticles are defined as an organic or non-organic structure of matter in at least one of its dimensions less than 100 nm. Nanoparticles proved their effectiveness in different fields because of their unique physicochemical properties. Using nanoparticles in the power field contributes to cleaning and decreasing environmental pollution, which means it is an environmentally friendly material. It could be used in many different parts of batteries, including an anode, cathode, and electrolyte. This study reviews different types of nanoparticles used in Lithium-ion batteries by collecting the advanced techniques for applying nanotechnology in batteries. In addition, this review presents an idea about the advantages and disadvantages of using nanoparticles in batteries to harness energy without harming the environment. This review showed that applying nanotechnology and using nanoparticles in the production technique of batteries open the field for developing energy storage in Nano sized batteries. This, in turn, is important in the new era of technology in the industries of electronic devices and precision electrical appliances such as mobile phones, digital cameras, etc.

Government-sponsored projects in Iraq significantly improve the economic situation and provide services but face high rates of troubling blocks. This work aims to identify indicative factors of the Troubled Project using periodic health check reports based on a literature review and interviews with Iraqi experts. As a result, a questionnaire was prepared that included four sections. The first is personal information; the second section is information about knowing the level of institutions’ implementation of project management through prepared documents. The third section is about indicative factors for the project's trouble, including 25 workers; the fourth section is about the questions in the periodic reports to check the project's health. Findings show that the following factors affect the troubled projects: inaccurate initial budget and schedule estimates; poor project scope description; poor team communication; poor planning and definition of the project; lack of a risk management plan and disregarding risk indicators; high rate of rework, and ineffective documentation of project plans with a high relative importance index that ranges from 0.91 to 0.81. Thus, the institutions' activation of the project examination reports with the proposed questions with a relative importance index ranging from 0.88 to 0.77 helps identify the main factors for the troubled projects.

This study looks into the many methods that are used in the risk assessment procedure that is used in the construction industry nowadays. As a result of the slow adoption of novel assessment methods, professionals frequently resort to strategies that have previously been validated as being successful. When it comes to risk assessment, having a precise analytical tool that uses the cost of risk as a measurement and draws on the knowledge of professionals could potentially assist bridge the gap between theory and practice. This step will examine relevant literature, sort articles according to their published year, and identify domains and qualities. Consequently, the most significant findings have been presented in a manner that is consistent with logic and is predicated on the temporal evolution between 1990 and 2015.

Wellbore instability is a significant problem faced during drilling operations and causes loss of circulation, caving, stuck pipe, and well kick or blowout. These problems take extra time to treat and increase the Nonproductive Time (NPT). This paper aims to review the factors that influence the stability of wellbores and know the methods that have been reached to reduce them. Based on a current survey, the factors that affect the stability of the wellbore are far-field stress, rock mechanical properties, natural fractures, pore pressure, wellbore trajectory, drilling fluid chemicals, mobile formations, naturally over-pressured shale collapse, mud weight, temperature, and time. Also, the most suitable ways to reduce wellbore instability are selecting the appropriate drilling mud and maintenance, reducing the Equivalent Circulating Density (ECD) by using suitable hydraulics, selecting hole-trajectory, and compatibility of drilling fluid with the formation being drilled. Moreover, factors such as (minimizing time spent open hole, using offset-well data, and monitoring trend changes (torque, circulating pressure, drag) must be considered. As a result of this paper, wellbore instability problems can be controlled by careful study of reservoirs to find the solutions to some issues or reduce them.

تتناول هذه الد ا رسة تأثير استخدام مثبتات التقوية )الرواسي( مثل اللف النسيجي والمسامير الميكانيكية واستخدام التعشيق لصفائح
الكاربون المثبتة أسفل العتبات على زيادة كفاءة استخدام مركبات الكاربون البوليمرية في تقوية الانحناء والمثبتة بشكل طولي
أسفل العتبات والتي تكون معرضة الى تلف جزئي في الجدائل حوالي 14.3 ٪ من مساحة ضفائر الشد الفولاذية، وتأثير التقوية
)التدعيم( على استعادة القدرة التصميمة للعتبات سابقة الاجهاد. وتتضمن د ا رسة المتغي ا رت الخاصة بالصفائح الأفقية CFRP
وتأثيرها على المقاومة للمقاطع. بالإضافة الى تأثير استخدام المثبتات )الرواسي( على الاجهادات المسلطة على المقاطع، وكذلك
تطور التشققات وانماط الفشل. أظهرت النتائج التجريبية أن استخدام رقائق البوليمر المقوى بألياف الكربون له تأثير كبير على
انفعال ضفائر الشد، حيث أظهرت النتائج التجريبية أن استخدام رقائق البوليمر المقوى بألياف الكربون له تأثير كبير على إجهاد
الضفائر، خاصة عند تطبيق اللف النسيجي. عززت صفائح الكاربون فايبر البوليمرية والملصقة خارجيا قد رة الانحناء بحوالي
13 ٪، لنسبة ضفائر تالفة بحوالي 13 ٪ من المساحة الكلية للضفائر. بالإضافة الى ذلك فقد اظهرت الد ا رسة زيادة قدرة الانحناء
بنسبة 20 ،٪ 22 ,% 29 ٪ عند استخدام اللف النسيجي، والمسامير الميكانيكية، والتعشيق لصفائح الكاربون على التوالي. تم
اقت ا رح استخدام معادلات شبه تجريبية لتقدير الضغط الفعلي للضفائر الغير محشو، مع الأخذ في الاعتبار تأثير استخدام صفائح
الكاربون واستخدام تقنية اللف النسيجي. وقد أظهرت النتائج التجريبية أن استخدام الرواسي له تأثير واضح وكبير على زيادة في
قابلية تحمل الاحمال كذلك حمل التشقق وبنسبة تصل الى 29 % بالإضافة الى تأخير عملية الفصل.

Construction projects are characterized as projects with multi phases and activities, complex, unique, and have many different parties and stakeholders. Risks could appear at one or more of the construction project stages and may affect the achievement of project objectives. Therefore, one of the key elements in the planning phase of any project is the risk management process (RMP). This study attempts to understand the terminology of risk in general, risk management, and response to risk in particular. This study is mainly a review of thirty-eight studies that have been published between 1997 and 2020 that demonstrate the importance of the crucial phase of risk response from the risk management process and its impact on the project objectives, as well as the tools and methodologies that project managers and decision-makers could use to handle the risks to reduce the negative effects of risks on the success of the construction projects. This study concludes that risk response should be considered an essential activity to complete the RMP, which will lead to minimizing the losses due to risks, maximizing the benefits due to opportunities, and achieving the objectives of projects.

The Diyala River is considered the third most important river in Iraq. However, in the recent period, Diyala Governorate has been subject to several floods. This study aims to simulate an efficient labyrinth weir at the flood escape entrance branching from the Diyala River to reach the best entrance through which the flood waves can pass safely. The discharge coefficient was calculated laboratory for five types of trapezoidal side labyrinth weirs with different sidewall angles. Results showed that the coefficient discharge for the trapezoidal labyrinth side weir with an angle of the sidewall is 75ᵒ and has a discharge coefficient greater than the rest of the labyrinth side weirs. The second part of this study is validating the laboratory work using the CFD technique, where the same laboratory channel was simulated with the weirs of the side trapezoidal labyrinth using the Ansys-Fluent program. The numerical study gave very close results compared with the experimental results with MSE, where the error percentage error was from 3.3% to 10%. The last part of the work is numerically simulating the trapezoidal labyrinth side weir with an angle of the sidewall of 75ᵒ at the flood escape entrance branching from the Diyala River. The results showed that the side labyrinth weir has a larger discharge capacity of 4.8% than the rest of the traditional weirs and is more effective in flood treatment.

The study uses ABAQUS software to model prestressed concrete hunched beams with multi-openings of various shapes. Finite element analysis was employed to investigate flexural behavior, stress distribution, and crack patterns. Results showed excellent agreement between simulations and experimental tests, validating the method's reliability for structural optimization.

The research identifies 17 key constraints affecting investment projects in Iraq, such as administrative delays and lack of coordination. A proposed system integrates administrative and technological solutions to organize procedures, reduce inefficiencies, and ensure transparency. Recommendations emphasize digitization and centralized management to improve investment processes.