Al-Qadisiyah Journal for Engineering Sciences

Systems for heating and cooling that use renewable energy are becoming more popular. One method for lowering ventilation heat losses and enhancing thermal comfort in buildings is the use of earth tube heat exchangers to heat or cool the air. Earth Tube Heat Exchanger is an apparatus that transfers heat from ambient air to underground and vice versa which is used in heating and cooling applications. It started using an Earth tube heat exchanger (ETHE) by relying on the use of sustainable energy sources. Numerous researchers have put many different concepts into practice, carried out studies on ETHE with various parameters based on location, and discovered the best values of parameters for improved performance. This paper reviews ETHE's experimental and numerical research which focuses on its design (Construction materials, distance from the earth's surface, air speed, and pipe length, among other factors). The use of geothermal energy (sustainable energy source) through ETHE leads to meeting energy demand and preserving the environment by reducing carbon dioxide emissions, which in turn affects the ozone.

In last years, a new type of pavement has gained popularity, this type is called Semi-Flexible Pavement (SFP). It consists of porous asphalt with high air voids between (25-35) % filled with cementitious grout materials. This type of pavement substance offers substantial advantages over both common types of pavements (concrete and flexible) such as good resistance to rutting and durability. SFP is considered an alternative pavement to exceed the drawbacks that occur for both flexible and concrete pavements. SFP has good features against permanent deformation, oil spillage, and fatigue resistance. Previous studies have shown that it can be used in a variety of applications such as highways, motorways, bridge deck pavement, tunnels, industrial areas with industrial equipment traffic, airport aprons, and stations. The goal of this research is to identify and compile the most significant research papers using the Web of Science (WOS), analyze the data using the VOS viewer software, as well as learn which countries and institutions had published the most articles relating to the subject of cementitious grout material as it relates to semi-flexible. It was also done to learn more about the authors and their collaboration. In addition to knowing the keywords that will aid researchers in their research on this topic, using these studies to better understand the elements that affect how well semi-flexible mixtures and grouts perform such as porous asphalt Mixture gradation and grout material components.

A propeller generates lift in the direction of revolution, similar to a revolving wing. Many previous propeller optimization techniques exist; nevertheless, they often find the optimal thrust coefficient at a constant power coefficient and vice versa. Using two types of algorithms, the genetic algorithm (GA), and the ant colony algorithm (ACO), and comparing with each other, this study will discover the optimal value of the thrust coefficient and the power coefficient combined to obtain the optimum value of the thrust and the lowest value of the power at the same time. A Simple Blade Element Theory Blade served as the foundation for all assumptions. This article examined over 80 various designs, brands, and types of propellers in a 2-blade configuration with diameters ranging from 2.5 to 19 inches and varying pitch values. The data for the baseline propeller was obtained from the UIUC Propeller Database. The inputs for the optimization are the propeller type, diameter, pitch angle, rotational speed, thrust coefficient, and power coefficient. The results show that by determining the factor of interest in the thrust coefficient (FITC), the algorithm can find the optimal propeller specifications. When the (FITC) is 100%, the algorithm will ignore the effect of the power coefficient and vice versa. In the instance (FITC) is 100 percent, the genetic algorithm performed much better than the ant colony algorithm (ACO). But the Ant colony algorithm is more accurate than the genetic algorithm.

In machining operations, surface roughness (Ra) is an essential measure of product quality. It is determined by the cutting settings. The parameters that have been worked on are the Feed (F) (0.72, 0.88, 0.96, 1.12 mm/min), depth of cut (DOC) (0.5mm), and spindle speed (N) (545, 710, 1000, 1400 rpm). Three types of ferrous metals were employed in this study low-carbon steel St 3, medium-carbon steel St 45, and high-carbon steel Y8. According to the data, the optimal operating condition for obtaining the best surface roughness is 1.119 µm for low-carbon steel. St 3 from the product is by employing the following cutting settings for the cutter (feed 0.72 = mm/rev), (DOC= 0.5mm), and (machine speed =1400 rpm). But when using the cutting variables (feed 1.12 = mm/rev), (DOC = 0.5mm), and (machine speed = 545 rpm) for high-carbon steel Y8, gives the highest surface roughness is 4.999 µm. The experimental findings indicate that the surface roughness of turned components is considerably affected by cutting settings and machine equipment. According to the results of this study, increasing spindle speed lowered the Ra of the turned components, but rising feed increased the surface roughness. The value acquired by this approach will benefit other researchers for future work on tool vibrations, cutting forces, and so on.

The reuse of recycling materials or industrial waste materials with aims to reduce environmental pollution strongly supports the concept of green building. Fly Ash is the result of the combustion of pulverized system coal at the PLTU Tenayan and is no longer included in the B3 waste category. The use of fly ash as a building material, mine restoration, and roads in this decade, is to replace cement or lime. The fly ash composition is mixed with lime for the sub-base and will be applied on high-plasticity soils. A fix-mixture of soil and lime 5%, mixed with fly ash up to 30% of the mixture. The samples test was made at optimum moisture content, with density values around the maximum dry density (MDD) i.e. under or above MDD. Consolidated testing was performed with and without curing. Changes in load are represented by the load increment ratio (LIR). The selected LIR values were 1.0; 1,5; and 2.0. The results showed that the higher of density, the volume of the void is lower. The soil compression index value is the same for all density values if the soil structure has not been destroyed. or fatigued yet. In samples with crushed/broken soil structures, the value of the compressibility index decreased sharply. Curing successfully decreased the void ratio and compressibility of the soil. The strength of fly ash will decrease when reacting with water, so if the soil is burdened, the void ratio decreases drastically. The formation of strong molecular bonds between fly ash and lime takes time. So, the compressibility value of the sample by curing for 28 days is better than without curing. The composition levels between fly ash and lime also affect the compressibility index of the mixture. The optimum combination occurs in samples with a fly ash content of 25%.

Designing an aircraft involves a lot of stages, however, airfoil selection remains one of the most crucial aspects of the design process. The type of airfoil chosen determines the lift on the aircraft wing and the drag on the aircraft fuselage. When a potential airfoil is identified, one of the first steps in deciding its optimality for the aircraft design requirements is to obtain its aerodynamic lift and drag coefficients. In the early stages of trying to select a candidate airfoil, which a whole part of the design process rests on, the conventional method for acquiring the aerodynamic coefficients is through Computational Fluid Dynamics Simulations (CFDs). However, CFD simulation is usually a computationally expensive, memory-demanding, and time-consuming iterative process; to circumvent this challenge, a data-driven model is proposed for the prediction of the lift coefficient of an airfoil in a transonic flow regime. Convolutional Neural Networks (CNNs) and Multi-Layer Perceptrons (MLPs) were used to develop a suitable model which can learn a set of usable patterns from an aerodynamic data corpus for the prediction of the lift coefficients of airfoils. Findings from the training revealed that the models (MLPs and CNNs) were able to accurately predict the lift coefficients of the airfoil.

Transformation plays a much more important role in every science. In this research article, two parametric forms of SEE transformation have been explored and the fundamental properties of two parametric SEE transformations have been shown. Furthermore, the transformed function of some fundamental functions and their time derivative rule has been shown. The application of two parametric SEE transformations in solving differential equations has been shown. The radioactive decay problem in first-order linear differential equations has been solved in this article which has large applications in nuclear energy engineering. Further, the solution to the beam deflection problem has been shown to have many applications in the engineering field. These results can be compared with other Laplace-type transformations.

Wind energy is one of the most important renewable energies since it reduces environmental pollution. Darrieus VAWTs with straight blades are more prevalent in small-scale power generation due to their simple blade design and easy construction. The investigation of the performance of VAWTs is a topic that is fascinating for researchers to look into. Researchers have paid special attention to the Double Multiple Stream tube (DMST) models for VAWT simulation because of the good correlation between the DMST model and the experimental results. In this paper, double multiple stream-tube analysis is performed using MATLAB programming to predict the aerodynamic performance of H-type Darrieus fixed pitch VAWT, more specifically, the power coefficient (Cp) and the tip speed ratio (TSR). The fact that the H-type Darrieus rotor has poor self-starting despite having a good power coefficient which is a constant worry at low wind speeds. The selection of the air foil is one of the most essential factors to take into account while trying to enhance the aerodynamic performance of H-type Darrieus fixed pitch VAWT. In this study, first, results from experiments were used for the validation of the model, and then, 4 different families of symmetrical air foils were compared. The results indicate that the symmetrical air foil S-1046 showed exceptional aerodynamic performance and a high starting torque for a low wind speed of 4 m/s.

The rotor position value is the most important parameter in synchronous machines. In this paper, a MATLAB model of high-resolution rotor position determination at zero speed, without any position sensor, is presented for a non-saturated permanent magnet motor. The motor current and voltage responses for two short pulses were employed to form address lines for memory cells whose contents represent the exact rotor position. The proposed model presents rotor position at 1o resolution and works with salient rotor poles. It could be modified to obtain the results for non-salient poles. The model needs only two current sensors and does not require any special technique for magnet polarity detection. This method was tested successfully for a two-poles machine, and it could be applicable to any number of poles. The statistical analysis, regarding the uniform distribution of the rotor position angles, supported the validity of the proposed method.

Spatial adaptability is the ability of floor plans to adapt to families' changing needs and requirements over time. Apartment floor plans that are not designed according to the user's preferences cannot meet his or her changing needs over time. So, an adaptable apartment floor plan is considered a desirable alternative that can provide various solutions to households' changing spatial needs in the present and the future. Future low-income apartment designs will be more effective if users select the most appropriate types of floor plan adaptability for their needs and culture. The aim of this study is to identify user preferences for the types of adaptability of floor plans and assess the adaptability capacity of low-income apartment floor plans based on those preferences. Based on the research criteria, six low-income multi-family residential buildings in Erbil City were chosen as case studies. The questionnaire was conducted through face-to-face interviews with 363 participants. The study used mixed methodologies, including a quantitative questionnaire survey and a qualitative case study analysis method, to answer the research questions. This study concluded that users did not prefer all the types of spatial adaptability; they preferred the ones that most suited their needs, lifestyles, and preferences. Low-income apartment floor plans didn’t support user preferences, and residents of low-income apartments in Erbil City could not adapt their apartment floor plans according to their preferences. According to the findings of this study, there should be a greater emphasis on the future design of low-income apartment floor plans in order to meet the changing space needs and requirements of families. This study can help architects and policymakers improve housing quality in Erbil City by considering user preferences for space adaptation when designing low-income apartment floor plans in the future.