Al-Qadisiyah Journal for Engineering Sciences

Using waste materials and by-products from various building sectors is gaining popularity because natural resources are quickly depleting. Geopolymer concrete is made from by-product material and is a relatively new environmental material that does not require the presence of ordinary Portland cement as a binder. This study involves producing lightweight geopolymer concretes using a slag binder and replacing the conventional fine and coarse aggregates with two types of locally available lightweight aggregate (thermostone and montmorillonite). Several sequential steps were used to process the aggregates, along with a series of tests conducted to evaluate the concrete properties in different states. The fresh state test includes the slump test, while the hardened concrete tests involve compressive strength, flexural strength, density, thermal conductivity, and water absorption. This study reveals the suitability of lightweight concrete mixtures for various constructional applications. The most reliable mixture was the GMM, which consisted of coarse montmorillonite (5–25 mm) and fine montmorillonite aggregates. This mixture exhibited the highest compressive strength of 23.3 MPa, a flexural strength of 3.25 MPa compared to other LWGC mixtures, and a low density of 1785 kg/m3. The GMM density was 23.97% lower than the reference mixture, whereas the thermal insulation significantly improved by 65.58%. Consequently, this improvement was evident in the thermal conductivity coefficient, which measured as approximately 0.349 W/m.K. In addition, the GTT mixture containing thermostone aggregate (5-25 mm) yielded the most optimal thermal insulation and lowest density of 0.267 W/m.K and 1552 kg/m3, respectively. In general, the strength and density of the LWGC mixtures in this study meet the requirements of lightweight structural applications.

Due to urbanization, it has been found that in many cases public open spaces in the city are not maintained, as new investments are trying to make use of the land to construct more buildings The shortage of public open spaces can be treated by providing a sufficient amount of private open spaces in housing estates. Furthermore, the designers need to consider the dwelling layout to provide the best environment for the residents; this will maintain a high level of household satisfaction. One main element of household satisfaction is open spaces. In this research paper, private open space assessments in 4 investment projects with 98 samples in Erbil were considered. To investigate and examine how the exterior environment of the dwellings affects the residents’ satisfaction, based on plot size and number of bedrooms, surveys were performed on selected projects through documentation surveys and questionnaires. Then the evaluation was performed through two stages, firstly the technical assessment stage according to Iraqi standards, and secondly the residents’ response stage regarding satisfaction levels. The research objectives were obtained using SPSS software, through the use of descriptive statistics, correlation, and regression analysis. The results of the research discovered that all the projects except Minara B were slightly above the minimum level, thus in the range of Iraqi standards. Moreover, the level of overall satisfaction with these projects ranged from neutral to slightly satisfied, with the residents’ responses stating that they needed more private open spaces.

Hydrodeoxygenation (HDO) is a critical step in upgrading biomass-derived feedstock to renewable fuels and valuable chemicals. Thus, preserving the environment through the use of agricultural waste. Water plays the role of solvent, reactant, or byproduct in biomass HDO reactions, which are catalyzed by Co/HB zeolite catalysts. In this investigation, The hydrodeoxygenation of linoleic acid was examined in a patch-packed-bed reactor with a beta zeolite range of (5-15) mg and catalyzed at a temperature range of 230-300 K for 2-3 h. Linoleic acid, an unsaturated fatty acid, was used in this work to create hydrocarbons in the diesel range, as well as to clarify the impact of zeolite quantity, temperature, and time on the yielded product, to produce biofuels from Linoleic acid by hydrodeoxygenation in the high-pressure reactor in the presence of the catalyst. The products are then characterized by gas chromatography-mass spectrometry (GC-MS). Based on the optimization results, it was determined that the hydrodeoxygenation reaction primarily eliminated the oxygen atoms from fatty acids. The yield of the intended products was 96.2% at the Co/HB zeolite amount (10% wt), high reaction temperature (270 ºC), and time (150 min) conditions.

The development of urban areas in Palestine is usually linked with the implementation of municipal road projects. The assessment of life cycle costs for municipal roads is presented in this research. This paper aims to highlight the main factors and their impact on the cost overrun during the different life cycle phases of road projects and therefore proposes recommendations that aim at reducing the differences between the estimated and actual costs. A study was conducted across twenty-six municipalities in the various regions of the West Bank. Over the study period of 2016 to 2018, there were 123 implemented road projects within these municipalities, where sixty-three of these projects surpassed their initial cost estimates and encountered cost overrun by an average of 26.9%. Among these, forty-seven projects were deemed suitable for research based on the assessment of the filled questionnaires by these municipalities. The main factors leading to cost overruns include challenging terrain, lack of specialized engineering offices for design and tender preparation, the timing of the tender release, awarding projects solely based on the lowest bids, changes during implementation, and financial constraints. Project cost measures that rely on professional management practices need to be considered in the planning designing, tendering, and implementing phases.

Pollutants in water bodies pose a serious threat to both the aquatic ecosystem and human health. Ion exchange is used as a chemical process to remove unwanted dissolved ions from water and wastewater, it is widely accepted in developing countries. This work provides a bibliometric examination of the status and trends of advanced ion exchange worldwide. This study was conducted using the Dimensions website to identify and collect the most important research papers. The retrieved manuscripts were organized through Microsoft Excel, and then VOS viewer was used to analyze the data by reviewing previous studies related to ion exchange used as a contaminant removal treatment. Additionally, Vos viewer was used to create maps and find out which countries, universities, and journals have published research articles on topics related to ion exchange, as well as authors who have studied the topic of ion exchange and their research and cooperation. Furthermore, Vos viewer was used to benefit from these studies and to learn the importance of ion exchange as a treatment for removing pollutants. The electroneutrality of the ion exchange (IOEX) process must always be maintained since it is a stoichiometric process. Search results for IOEX were exported from Dimensions to a CSV file, both coexisting, cooperations with affiliate countries and consortia were implemented on the full search results. Ion exchange treatment has been proven effective in treating industrial wastewater and domestic wastewater. Professionals and practitioners in the field are provided with important information through this analysis of ion exchange research. The analysts, throughout this work, learned about leading academic and research institutions, the state of the exploration field, and the most controversial issues surrounding advanced ion exchange. In addition, this work provides the opportunity to learn basic facts thus developing the extent of the reader’s ion exchange knowledge. The bibliometric survey method can also be used to visualize the trends of research and study in various fields.

The manufacturing process of materials utilized in concrete production has environmental implications. The production of cement releases significant amounts of greenhouse gases, while the extraction of aggregates and sand poses challenges to the natural environment. To minimize the aforementioned challenges researchers are suggested to utilize industrial by-products as a partial alternative for these materials Fly ash, stone dust, GGBS, silica fume, and metakaolin are widely utilized alternatives to construction materials. The specific use of clastic sand as a partial substitute for fine aggregate has recently gained popularity . However, studies on the characteristics of concrete prepared using cementitious materials and clastic sand are very few. In this work, the effect of clastic sand with ground granulated blast furnace slag concrete is being investigated. The GGBS is added in place of cement from 0% to 45%. Further, clastic sand is added in different proportions in GGBS concrete. The electrical resistivity, water absorption, acid attack, and micro-structural studies are carried out on all mixes to know the durability properties. The results confirm that the addition of GGBS as a cementitious material enhances durability. The inclusion of 35% of GGBS as a substitute for cement is optimum for enhancing durability. Further, the inclusion of 35% GGBS as a cement substitute and 20% clastic sand shows a dense matrix and optimum results in enhancing durability. This is due to the pozzolanic activity of GGBS and clastic sand works as filler materials. This investigation suggests utilizing clastic sand along with GGBS as a cementitious material.

Cement is the most important component in cementitious grout production,andtt accounts for 7% of global greenhouse gas emissions. Reducing the amount of cement used in infrastructure and buildings is a desirable way to lower the total carbon footprint associated with grout production. relatedly, developments in manufacturing and transportation lead to the production of cars in large numbers, which in turn leads to an increase in the production of byproduct waste like waste tires, which are thrown away directly without recycling. Thus, this study aims to develop a novel sustainable grout by recycling paper sludge ash waste (PSA) and waste steel fiber (WSF) as partial cement replacements. This will help reduce grout production costs, minimize environmental pollution during cement production, and enhance landfill and waste management. The Grout mixtures used in this paper were prepared using ordinary Portland cement (OPC), WSF extracted from vehicle tires, PSA, and water. Different proportions of WSF(0, 1, 2, 3%) and PSA(5, 10%) were used in the weight of cement in designing sustainable grout. The mechanical properties of the sustainable grout were evaluated by examining extensive tests including flow tables, compressive strength, and flexural strength. The results showed that partially replacing the cement with 3% WSF and 1% WSP with 5% PSA resulted in a significant improvement in workability ,as well as a clear increase in compressive and flexural strength at an early age compared to the reference mixture.

The quality of the acoustic environment plays a crucial role in shaping human communication and comfort within a space. This is particularly true for outdoor performance venues like amphitheaters. This study explores the potential of soundscape design to optimize acoustic comfort for audiences in the unique setting of a rainforest amphitheater. Rainforests, characterized by dense vegetation and uneven terrain, present both challenges and opportunities for acoustic design. While they may introduce unwanted background noise, the inherent properties of rainforest trees offer valuable potential for passive noise absorption. This research investigates how existing trees can be strategically integrated into the amphitheater design to utilize their natural sound-absorbing capabilities. The primary objective is to achieve a balanced soundscape that maximizes visitor comfort during performances. Initial findings suggest that strategically utilizing trees as noise buffers while preserving natural soundscape elements can be a viable approach. Furthermore, creating a diversity of dynamic sonic areas within the amphitheater appears promising in catering to individual preferences and enhancing overall acoustic comfort for the community. Ultimately, this study seeks a harmonious solution that optimizes performance acoustics for visitors while preserving the unique soundscape of the rainforest environment.

The digital voltage controller of power converters is used because it has many advantages over its analog counterparts. Thus, in this paper, a controller of digital voltage mode is designed and analyzed for a non-isolated DC-DC buck converter in continuous conduction mode (CCM). First, an analog controller is designed using a Bode plot to achieve the desired stability margins in the frequency domain. Next, the analog controller is discretized using bilinear transformation with the pre-warping method. The characteristics of the discretized compensator can be maintained close to the corresponding analog compensator as long as a proper sampling time is selected. The digital control scheme is simulated with a nonlinear DC-DC buck converter model in MATLAB/Simulink to investigate the controller performance. The simulation results demonstrated the validation of the proposed digital voltage-mode control design approach. The developed digital controller eliminates DC error by tracking the reference voltage, achieving a fast transient response, maintaining specified stability margins, and effectively rejecting large disturbances.

Corrosion is one of the main sources of failure for metals and alloys, thus it is a major engineering problem. Engineers must consider the corrosion of metals in different environments when designing engineering parts. Metals tend to corrode in different media; they show different behaviors due to differences in chemical composition and the severity of the corrosive medium. In tap water, the corrosion of mild steel products is an electrochemical phenomenon that includes two reactions: the dissolving of iron (anodic) and the reduction of oxygen (cathodic). This work observes the corrosion behavior of welded low-carbon steel by Friction Welding (FW), Shielded Metal Arc Welding (SMAW) , and MIG welding techniques using immersion tests in tap water at different periods. The results revealed that while the corrosion rate of Base Metal (BM) increases, it reaches a nearly steady state in the friction-welded and SMAW-welded samples. The difference in the corrosion rate of the welded samples can be attributed to changes in the concentrations of Cl– and CaCO3 ,as well as the pH values of the corrosive mediums. Pits could be observed in the microstructure of the nugget zone for all weldments.

Solar fireplaces are important in remote areas with abundant solar radiation,they are a sustainable and environmentally friendly alternative to traditional cooking methods as they do not emit toxic gases. This study aims to experimentally compare solar box cookers of different designs, materials, and features to understand heat transfer and thermal performance to improve overall efficiency. Four different cases with different materials and features of the box structure are studied: Case 1 - non-tinted wooden sides, case 2 - black tinted wooden sides, case 3 - box with glass sides, and Case 4-black tinted wooden sides and coated inside with aluminum foil. Two designs are compared for each case- one with a front flat mirror and one without. All solar fireplaces consist of an inclined glass facing at an angle to the latitude of Baghdad and a base with black fins. The experiments last for three months in various weather conditions including cold, hot, dusty,andsunny daysin southern Baghdad, Iraq, positioned at Latitude 33.2 o north and longitude 44.42 o East. Factors such as the intensity of incident radiation, wind speed, and ambient air temperature are taken into account during the cooking period. The results indicate that the third glass-sided box achieved the highest thermal efficiency of 93.7% after 120 minutes. The rice was fully cooked in just 97 minutes, the quickest time ever seen with this type of solar cooker, and had a thermal efficiency of 88%. The fourth box, lined with aluminium foil on the inside, succeeded the third book with Rice reaching ripeness at 110 minutes with an 80.5% efficiency.

This paper presents an experimental investigation of thermal insulation in rubberized concrete blocks, where the fine aggregate size was replaced by rubber crumbs at varying ratios (0%, 10%, 20%, 30%, 40%, and 50%). The rubber crumbs used in this study ranged in size from 0-1mm, 1-3mm, and 2-4mm. A mixing ratio of 4:2:1 was employed, and simulated solar energy at a rate of 500 W/m2 was applied to the outer surface of the test samples. Heat flux sensors were installed on both the internal and external surfaces to measure transient heat flux through the samples, while K-type sensors were used to measure surface temperatures. The samples were placed in an adiabatic room with an open front side for testing. The results of the study indicate that the addition of rubber crumbs to the concrete mixture improves thermal insulation properties, as evidenced by a decrease in thermal conductivity corresponding to the volumetric substitution ratio of rubber crumbs with the volume of sand in the sample. Particularly, a 50% incorporation of rubber crumbs led to a substantial 76.2% reduction in thermal conductivity, indicating the effective thermal insulation provided by rubberized concrete. These findings hold significant implications for energy conservation within the building sector, where the use of rubberized concrete can contribute to improved energy efficiency and reduced heat transfer.