DIYALA JOURNAL OF ENGINEERING SCIENCES

Free convection is widely used in engineering applications, including solar energy, electronic devices, nuclear energy and heat exchangers. A computational simulation utilising Ansys Fluent-CFD was used to examine the natural convection heat transfer inside a square cavity filled with pure water and saturated metal foam as a porous medium (porosity ɛ=0.9). The enclosure’s lower wavy wall exhibits a high temperature (Th), whereas the side and upper walls display a low temperature (Tc). For different Rayleigh numbers, the study examines hump configuration and the bottom wall hump number (N). The predominant design of heat transmission was improved using the circular hump design parameters of ɛ=0.9, N=4 and Tc=25 °C for different Ra. The novelty of the research included determining the optimal design for the square enclosure. This approach involved estimating the effects of hump configuration and the number of humps for the bottom wall of the enclosure. These parameters have not been studied yet. The optimum case showed the highest heat transfer coefficient (h) at the circular hump, N=4 and Ra=30´103, whereas the standard case obtained N=0 and Ra=5´103. The CFD simulation results indicate that the primary objective of the study was achieved through the optimal design, resulting in a significant enhancement of hydrothermal performance for heat transfer enhancement and energy enhancement 1.13 times compared with the standard case.

Global warming is a serious concern worldwide, and many sources contribute to the rise in the temperature of Earth. One major source is air pollution. It is of utmost importance to apply the necessary remedial actions to address the contaminants in outdoor and indoor environments. In this research, a step is taken to treat flue gases, for which membrane technology is introduced. A porous ceramic membrane is synthesised from calcined porous alumina (Al2O3) and activated washed fly ash. Some other additives such as starch (C6H10O5) n, binder solution along with ethyl silicate (C8H2O4Si) and a deflocculating agent carbonic acid (H2CO3) are employed. Some of the issues faced during the fabrication of a porous ceramic membrane are discussed, i.e., cracks in membrane sample, nonactive reactant issue, uneven rise or fall during demoisturisation or sintering steps. The membrane sample is characterised through different tests, including thermogravimetric analysis and DTG. Satisfactory results are obtained, with a negligible percentage weight loss after 750 °C. X-ray fluorescence for fly ash portrayal and X-ray diffraction analysis for structure assessment are conducted, which describe that the fabricated membrane has a crystalline structure similar to ceramic. Archimedes’ principle is used to determine the bulk density and porosity of the membrane sample, and the values are 4.484 g/cm3 and 62.5%, respectively. An average pore size of 7.6 µm is identified through optical microscopy, and the mechanical strength is determined to be 2.7 MPa. Furthermore, a pilot-scale visual permeability test is performed for flue gas treatment of combustion fuel containing tyre and coal powder. The results show the compatibility of the fabricated porous ceramic membrane to be utilised for the treatment of flue gases.

This study conducts biogenic synthesis of Ag-MnO nanocomposites whose aqueous extract from Cyttaranthus congolensis was used as a reducer and stabiliser. The characterisation of these particles by UV–visible spectroscopy made it possible to identify the band linked to the surface plasmon resonance located at approximately 380 nm. X-ray diffraction and fluorescence allowed determining the presence of particles of formula Ag 0.21 Mn 0.28 O having crystallised in a monoclinic system (a= 5.8517 , b = 3.4674 , c = 5.4838 and β = 107.663°). A spherical morphology was observed by scanning electron microscopy. The haemolytic activity carried out on human blood indicated that Ag-MnO nanocomposites are not toxic to human blood. Moreover, these particles showed a good antibacterial activity against gram-positive and gram-negative strains of bacteria. Promising results on the anthelmintic activity of Ag-MnO nanocomposites against several pathogenic helminths are reported in this paper. In addition to antibacterial and anthelmintic activities, Ag-MnO nanocomposites also exhibited good anti-inflammatory and antioxidant activities.

Stainless steel has been widely used in the building industry as load-bearing elements such as beams and columns. Many fire accidents in stainless steel buildings were recorded, but only a few have collapsed entirely. These buildings can be rehabilitated and the undamaged parts can be reused, which reduces the economic losses in buildings exposed to fire. The residual mechanical properties of stainless steel after the fire, are the primary determinant of the validity of the stainless steel structure. In this paper, the effect of high temperatures and the time of exposure and cooling method on the mechanical properties of S304 stainless steel was studied. The specimens were heated to 800°C and 1000°C for different heating times (30, 60,90 and 120 minutes) and cooling methods (air-cooled and water-cooled). Results showed that the post-fire yield stress was reduced by 24% and 18% after heating to 800°C for 120minutes and cooled in water and air respectively. However, heating to 1000°C showed a marginal effect on the yield stress of air-cooled specimens and a clear reduction (29%) in the water-cooled specimens. Elongation capacity increased with heating time for 1000oC specimens but decreased for 800oC specimens in both cooling methods.

Building materials have shown remarkable progress, as many methods have been used to enhance their properties, such as nanomaterials which have played a major role in this field. This research reveals the complex integration of nano-zirconia (NZrO2-5wt%YPSZ) with concrete and its effect on different mechanical properties. The main objective of this research is to reduce the porosity of concrete by adding doses of nano-zirconia to the concrete mixture to enhance the microstructure, thereby improving its mechanical properties. Results showed that the addition of nano-zirconia decreased concrete slump and increased the rates of absorption and porosity because of the agglomeration of nanoparticles. The compressive strength increased to 30, 47.5 and 60 MPa at the ages of 7, 28 and 90 days, respectively. The splitting tensile strength increased when the zirconia content was increased, reaching its highest level when substituting 0.7wt% compared with the reference mixture. In summary, this study sheds light on the effect of nano-zirconia on the mechanical properties of concrete by filling the pores, which enhances its microstructure because it reshapes the complex texture of the concrete mixture.

This study focused on investigating the impact of α-Al2O3 nanoparticles on heat transfer in shell and helical coiled tube heat exchangers. The objective was to analyze the influence of various geometrical characteristics, specifically the coil pitch, on the Nusselt numbers of both sides using a combination of numerical simulations and experimental methods. The working fluid for the hot side was water. The research encompassed an examination of the friction factor for three different coils, exploring the effects of pitch spacing on heat transfer, and assessing the influence of nanoparticles on heat transfer on the inner side of the coil. The findings of the current work indicated significant improvements in heat transfer parameters when employing water-α-Al2O3 nanoparticles as the cold fluid. Comparing this heat exchanger to one without the inclusion of α-Al2O3 nanoparticles revealed a remarkable efficiency enhancement of 7.68 percent. This increase strongly suggests a notable acceleration in the rate of heat transmission within the heat exchanger. Overall, this study provides valuable insights into the utilization of α-Al2O3 nanoparticles in enhancing heat transfer in shell and helical coiled tube heat exchangers. The results highlight the potential benefits of incorporating nanoparticles into such systems, leading to improved performance and more efficient heat exchange processes.

In general Pile foundations are often subject to more than one load in nature. Two loadings, when simultaneous, cause serious problems in the bearing capacity. Therefore, the major objective of this study is to assessment the performance of piles under inclined cyclic loads simultaneous with static lateral loads in sandy soil with a relative density of 70%. A laboratory investigates were conducted to determine effect of several factors on group pile performance model (2×2), including: the ratio of spaces between piles (i.e. 3D, 5D, 7D), influence of inclination angles of cyclic loading (i.e. 0°, 10°, 20°, 30°), the cyclic load ratio (i.e. 20%, 40%, 60% and 80%) and the effect of the presence of a static lateral load on the cyclic load. In light of the findings, the presence of the static load with the inclined lateral cyclic load has a positive effect on the deep foundations where the lateral deflection was reduced by an average of 54% for the three spaces. Also the lateral deflection at combined lateral loading decreases with increasing pile spacing, the percentages of decreases in the lateral deflection were (16%, 73%, 75% ) for spacing (3D, 5D, 7D ) respectively

Due to rapid growing of population and active lifestyle, massive amounts of municipal solid waste (MSW) are produced worldwide. The MSW can harm the environment and threaten the land if the dumping sites are not managed scientifically. The geotechnical properties of MSW are the key parameters required in the landfill operations and waste management facilities. Hence, presence of the geotechnical properties data of the waste can assist engineers in selecting possible solutions for extension of the landfill and obtaining prior background data for the evaluation and design of landfills. MSW disposal changes the geotechnical properties of soil. Also, alterations in the geotechnical properties of soils may contribute to the physical and physico-chemical interactions between soil and contaminants of the dumping sites. As leachate, which is generated by the waste, penetrates into the soil, it moves pollutants into the soil and influences the strength and stability of the soil. The main objective of this research is to summarize the most recent literature of the physical and mechanical properties of MSW, and their influence on the geotechnical properties of soil. The findings of numerous investigations on the physical and mechanical characteristics of MSW and soil influenced by MSW are presented and discussed. Depending on the reviewed research studies, it can be observed that the engineering characteristics of MSW are complicated and varied for various reasons. The waste components and degradation process can cause an increase in moisture content and unit weight, and a decrease in organic content, hydraulic conductivity and compressibility of MSW. Additionally, MSW sites significantly impact the physical and mechanical characteristics of underlain and surrounding soil and deteriorate the soil quality. Further, it was noticed that the influence of dumping on soil is reduced with depth due to less interaction between the soil and waste

The stability of Electro Phoretic Deposition (EPD) suspensions containing nanoparticles relies on the impact of Zeta Potential (ZP or ). This property ensures that the nanoparticles have a consistent and stable surface charge, resulting in a uniform and stable coating. This research has been conducted as an experimental study and used the Taguchi method to design experiment optimization of the Zeta potential values, which were obtained by preparing nine suspensions. The study aimed to determine the optimal ZP value for the EPD suspension created with three materials mixed: nanochitason, Chitason/SrCl2/MgO, and a constant value of hydroxyapatite (HA) with consideration of the pH effect. After conducting an analysis, it was found that the suspension's Zeta Potential is negatively charged below a pH value of 8.22. Between 8.22 and 9.7, the ZP has a positive charge. The suspension's isoelectric point (IEP) is 8.22, with a high correlation coefficient indicating the model's reliability in predicting responses. The analysis showed that SrCl2 has the most significant impact on the suspension's ZP, followed by Chitason (CH), with MgO having the least impact. The results demonstrate the effectiveness of this analysis in determining the optimum ZP value for various solutions prepared from different biomaterial particles

Project systems are essential to the success of a construction project since they provide models and techniques recommended for construction planning. Performance is the most important part of the planning process. Despite the fact that the construction industry has traditionally been afflicted by insufficient planning and overdependence on tradition integrated planning, building information modelling (BIM) technology has frequently in recent years been proposed to increase the effectiveness of project performance in construction planning facilities. The practical goal of this research is to apply of BIM to enhance the effectiveness and efficiency of structural planning. A quantitative questionnaire was used to summarise the benefits and capabilities of these technological advances in the field of construction planning. As a result, the questionnaire was constructed based on prior research that dealt with positive benefits, and topics were generated in the research areas of cost, time, communications, conflicts, documentation, and other key indicators in the design phase and feasibility studies. The results were calculated from the relative means of the questionnaire filled for this purpose, and the average rate was 0.816 percent, reflecting the importance of this technique. Hence, the relative importance of structural planning will be relatively high due to its effectiveness in the built environment.

Designing a reliable routing protocol for Vehicular Ad hoc Network (VANET) poses considerable challenges due to certain unique challenges inherently present in Vehicular Ad hoc Network (VANET) topology. Some of them are needed for vehicles acting as nodes having to abide by traffic rules, uncertain inter-vehicular speed variations that may affect link stability etc. Designing a routing protocol capable of dealing with multiple limiting conditions such as long congestion periods, link failures and handoffs is a challenging task, where most of the existing multipath routing protocol shows poor performance. In this paper, the proposed Multipath Route Restoration Protocol (MRRP)is aimed at providing a robust communication channel in case of link failure between nodes. This is realized by focusing on better route maintenance for the protocol. In a wireless network, a routing protocol determines the particular ways in which routers connect. In a wireless network, as the number of hops in a wireless communication path increases, various signal factors such as interference and path loss degrade the network performance. however, sending data over a longer distance will reduce throughput. Furthermore, link stability is substantially impacted by the unpredictable movement of vehicles. Multipath routing is regarded as a potential solution to improve packet delivery and end-to-end delay in VANETs.

In this work, an experimental system was established to measure the heat transfer characteristics, including the heat transfer coefficient, overall heat transfer, Nusselt number, and thermal conductivity. The investigation focused on spring water and tap water-based nanofluids containing Fe2O3 and ZnO nanoparticles with particle sizes of 50 nm and 70 nm, respectively. The experiments were conducted inside an automobile engine, studying the effects of varying nanoparticle volume fractions at a constant temperature. Fe2O3 and ZnO concentration in the respective based fluids was verified between 0.02 % and 0.08 % v/v and 0.01 and 0.07 %, respectively. The spring water is not so far used in the previous studies and is much more available in Kurdistan region. Reynolds numbers of nanofluids inside the engine were considered between 1000 to 8000 in a different range as that of the literature review. Reynolds analogy for heat and momentum has been employed in this study. It was observed that the thermo-physio-mechanical properties of nanofluids increased with increase in the concentration of nanoparticles and Reynolds number. However, the friction factor decreased with increasing Reynolds number but increased with an increasing volume concentration of nanoparticles. Generally, the results showed that the enhancement of the effective heat transfer of the nanofluids reached 46%, the overall heat transfer coefficient reached 39%, thermal conductivity reached 21.35% and Nusselt number reached to 38%. at 0.08% volume fraction of Fe2O3/spring water nanofluid. Based on all previous parameters estimated, the designed nanofluids in this study could be classified as a workable nanofluid in many industry applications