Tikrit Journal of Engineering Sciences

Vanadium, one of the heavy metals present in crude oil, harmfully affects the equipment of oil refineries and the quality of petroleum products. As a result, it is important to innovate effective methods for reducing or removing its concentration. This paper aims to study removing vanadium metal from Iraqi crude oil using activated carbon as an effective adsorbent material. Different experimental factors, i.e., the activated carbon dose, contact time, and agitation speed, were regulatory varied to evaluate their impact on vanadium adsorption efficiency. The outcomes revealed an exceptionally good efficacy of activated carbon to eliminate vanadium. The results exhibited that the maximum remediation was 86.33%, recorded at optimum factors, i.e., 0.5 g of activated carbon, 400 rpm of agitation speed, 75 °C temperature, and time of 400 minutes. According to these findings, activated carbon has a great ability to adsorb vanadium from crude oil. Thus, it can be considered a sustainable material for treating petroleum. Furthermore, this approach will help the refineries by reducing costs by eliminating the heavy metals that lead to corrosion or poisoning catalysts.

Floods are considered the most serious disaster among all-natural catastrophes because they occur more frequently than any other natural hazard and strongly impact more individuals than all other natural disasters. Therefore, it is necessary to study flood risk. Hillah River is critical in securing industrial, agricultural, and civil water in three Iraqi governorates: Babil, Diwaniyah, and Muthanna. Its primary source is the Euphrates River, which extends approximately 100 kilometers within Babil Governorate – the study area. This research aims to evaluate and study the river's capacity and predict future floods by developing scenarios for anticipated events. Also, a hydraulic model was developed to assess the manning coefficient for Shatt Al-Hillah. The one-dimensional HEC-RAS 6.0.1 program has been used to simulate water flow in the river, incorporating over 350 cross-sections spaced at 250-meter intervals surveyed in 2018 by the Department of Water Resources in Babil Governorate. The model was calibrated using observed discharge data from 2004 to 2022 in Shatt al-Hillah. Subsequently, it was compared with a range of water levels by varying manning factors. The calibration results indicated that a roughness coefficient of 0.023 was suitable for unstable flow conditions, and the least mean square root error between the measured and simulated water levels was 0.053. The simulation results showed that the current capacity of Al-Hilla River was 205 m3/s, such that it cannot pass the design discharge of 303 m3/s. After conducting scenarios greater than 205 m3/s, the results showed that increasing the discharge increased the areas exposed to flooding so that when the discharge was 450 m3/s, flooding of the submerged areas increased. With a percentage of 92.2%, the northern side of Babil Governorate will be more vulnerable to flooding than the southern side because the southern part levels are lower than the northern part.

Hydro mechanical deep drawing (HMDD) is an emerging technology that reduces the number of sheet-forming stages and increases the production of advanced lightweight materials with intricate shapes. This study aims to verify the springback in HMDD and the effect of holding time and fluid pressure on this phenomenon (springback). The springback was measured using a new method by matching the projector p-300 axes with the cylindrical cup wall. The difference between the wall and the axis represents the springback value. Using a blank of low carbon steel (1008-AISI) with 80 mm of diameter and a thickness of 0.7 mm. The effect of holding time (1, 2, and 3 minutes) and the fluid pressure (0.6, 0.8, and 1 N/mm2) was studied. The used hydraulic oil was (code number 3803). The springback value of a cylindrical cup was calculated using the profile projector P-300. The result showed that the springback phenomenon was presented in the hydromechanical deep-drawing process but at a lower rate than the traditional deep-drawing process. The holding time and fluid pressure significantly affected the springback value. The springback decreased with increasing the fluid pressure and holding time.

This paper examines the experimental flexural performance of the strengthening composite concrete asymmetrical castellated steel beam of double channel shape by connecting two castellated hot rolled steel channels back-to-back using bolts along its length to obtain a built-up I-shaped form with a new total beam depth heightened by 52.4%. This research tested four specimens: the first was a reference specimen without any strengthening techniques; the second was strengthened with RPC (Reactive Powder Concrete) in the steel web region; the third was strengthened by RPC reinforced with a lacing rebar. Also, this study investigated the welding effects in web posts for the top and bottom parts of the castellated steel in the fourth specimen. All specimens were tested under simply supported conditions by applying two-point static loads on the concrete deck slab of the composite beams. The ultimate load deflection, stiffness, ductility, energy absorption capacity, and failure mode were investigated and discussed. According to the experimental results, the ultimate load capacity increased 24.01% and 48.34% in the second and third specimens, respectively, with increased stiffness, ductility, and energy absorption capacity compared with the first specimen. In contrast, the ultimate load capacity decreased by 11.02 % in the fourth specimen (strengthening without welding in web posts), reducing stiffness and ductility compared with the first specimen (reference).

Geopolymer concrete has superior physical properties and a positive environmental impact compared to conventional concrete. Waste management is one of the most essential issues. Regarding sustainable raw material management, recycling the industrial waste as much as possible and developing new technologies that reduce industrial waste landfills and generate materials with new added value is essential. Every year, people throw away about 17 million tons of tires that cannot be used again. This trash is a significant environmental threat, so recovering tires is essential. The results showed that replacing 10% of the crumbed rubber wastes with natural coarse aggregate decreased the workability, compressive strength, splitting tensile strength, flexural strength, and direct tensile strength by 5.5%, 38.6%, 10.6%, 6.25%, and 6.67%, respectively with respect to a reference without wastes. At the same time, adding 0.125% and 0.25% recycled steel fibers increased the workability reduction by 2.9% and 5.9% and improved mechanical properties, including compressive strength, splitting tensile strength, direct tensile strength, and flexural strength by 43.3%, 15.9%, 26.4%, 14.2%, 90.4%, 42.4%, 32.1%, and 17.9%, respectively, compared to a reference mixture containing 10% crumbed rubber wastes. The results also showed an increase in the total energy by 23.2%, 142.4%, and 312.1% when replacing 10% of the natural coarse aggregate with crumbed rubber wastes, including 0.125 and 0.25% recycled steel fibers, respectively. When these wastes were introduced together or individually, Brittleness of geopolymer concrete changed to ductile.

As many residential homes and structures were destroyed or badly damaged because of the military battle in Iraq, it is critical to recycle construction debris widely in the rebuilding and decoration of buildings and infrastructure. This battle resulted in the buildup of massive construction debris, and recycling this waste allows for a cleaner environment. Recycling the construction waste of various installations is an urgent need to decrease the consumption of natural materials and landfills of construction waste, and as a result reduce the environmental pollution. Therefore, this study is a local focus on using concrete debris to obtain high packing density recycled coarse and fine aggregates in various fractions of (0.16 mm - 10 mm) by selecting high-density packing materials that was developed by Kharkhadin A.N in laboratories of Belgorod State Technical University in Russia to preparing of reference mix from ordinary density recycled aggregate. The new concrete samples for two concrete mixtures were prepared, to identify and study the important specifications. Models of cubes and standard prisms were prepared to evaluate the compressive strength and the splitting tensile strength. Also, the modulus of rupture and the unit weight were conducted. The results indicated an increase in the concrete’s mechanical properties using the high-packing density recycled aggregate. The obtained compressive strength, splitting tensile strength and modulus of rupture were (49) MPa, (3.6) MPa, and (7.1) MPa compared with a reference mix (39) MPa, (3.3) MPa and (6.3) MPa, respectively. The reference mix corresponding properties were (39) MPa, (3.3) MPa, and (6.3) MPa, respectively. Also the values of an oven-dry density were (2340) kg/m3 compared with the reference mix (2260kg/m³). These results proved that increasing the packing density of recycled aggregate enhanced the concrete’s strength properties.

Two key axes dominated this experimental research. The first was developing self-compacting concrete from ceramic waste powder (CWP) and glass waste powder (GWP), which met and followed the recommended European specification and guidelines for self-compacting concrete (EFNARC) standards. The second axis indicated the self-compacting concrete's rheological and mechanical performance. Sixteen different mixtures were produced using supplementary cementitious materials (SCMs) to replace cement partially. The replacement levels of SCMs were 5%, 10%, and 15% (by weight of cement), divided into three series: Series A (containing ceramic waste powder), Series B (containing glass waste powder), and Series C (containing combinations of ceramic waste powder and glass waste powder). The SCC rheological properties for all mixtures with different levels of SCMs replacement in the mixture gradually decreased as the substitution ratios increased. The reduction in flowability for substitution, ranging from 5% to 35%, was approximately 0% to 12%, respectively. However, the reduction was insignificant; the fresh properties remained within the limits specified by EFNARC. Regarding the mechanical properties, at an early age, the strength of mixtures decreased with increasing alternative ratios. However, after 90 days, the strength increased by about 11% and 9% of the compressive and flexural strengths, respectively, over the control mix, indicating that SCMs improve the concrete strength over time and are suitable to contribute to an eco-friendly concrete industry without compromising strength.

The global demand for more digital data motivates the evolution of mobile communication systems from 2G and 3G to 4G and 5G to support high data rate applications. The International Mobile Telecommuication-2020 (IMT-2020) defined the minimum technical performance requirements and guidelines for evaluating the 5G mobile cellular system. The New Radio (NR) millimeter wave (mmWave) and massive Multiple Input Multiple Output (mMIMO) antenna systems are technologies used in the 5G cellular system. Therefore, this paper studies the performance of the mmWave system combined with the mMIMO antenna system using the IMT-2020 channel model in a dense urban microenvironment, considering different frequency bands and numbers of elements at the Base Station (BS) antenna array. The performance is evaluated through system-level simulation in terms of Signal power to Noise power Ratio (SNR), Spectral Efficiency (SE), and cell edge user SE. A cell size reduction technique is proposed to meet the target requirements set by IMT-2020. Simulation results showed that the sub. 6 GHz frequency bands achieve the target SE of IMT-2020, while in the mmWave frequency range, the target SE requirement can be achieved using a high number of antenna elements at the BS antenna for some frequency bands.

This study aims to assess the performance of three drought indices for drought monitoring to study the characteristics of meteorological drought in Iraq, which are the Standard Precipitation Index (SPI), the China-Z Index (CZI), and the Modified China-Z Index (MCZI) on 1-, 3-, 6-, 9-, and 12-month timescales, using monthly precipitation data from 1980 to 2021. These indices were used to analyze the spatiotemporal dynamics of droughts using the rainfall data collected from five meteorological stations scattered across the four climatic zones as classified by Köppen in Iraq. According to the study, the Pearson correlation coefficient (r) values among the indices increase with increasing time scale and give similar drought characteristics at the 9-month and 12-month time scales. SPI generally indicated the drought event earlier and with more severe characteristics than the other indices. MCZI showed wetness earlier than the other two indices, and it also described the drought categories similarly to SPI and CZI, especially in the northern regions of Iraq, but it was less official in describing it as we headed down to the south. While CZI described the drought as having less severity than SPI, it frequently gives the same classifications of drought as SPI. CZI could be used as a good meteorological drought monitor, depending on the month, the length of the drought duration, and the climatic conditions of the region. It might be an alternative to the SPI, which needs long rainfall records and has a complicated structure. SPI and CZI can be considered good indices for describing drought in all regions of Iraq. The result shows that 1980, 1993, 1995, and 2019 were the most wet years; 2007–2010 was the most severe drought event; and Iraq's climate was normal to moderate drought during the studied period for all considered stations.

The ZnO/CdS/CNTS solar cell was simulated using the SCAPS program. It was found that increasing the concentration of the accepter and the thickness of the absorber layer increased (ɳ, Voc) and decreased (FF). The best concentration was 1.0×12 cm-3, and the best thickness was (2.5µm). Increasing the lift time of minority carriers increased (ɳ, FF, Jsc) and decreased (Voc). Adding a back-reflection layer (BSF) increased the conversion efficiency from 14.07 % to 15.15%. The effect of increasing the acceptor concentration in the reflection layer was similar to the absorption layer; however, increasing the thickness was opposite to the absorption layer, meaning it increases (FF) and decreases (ɳ, Voc). The results showed that increasing the shunt resistance increased (ɳ, FF, Voc), while increasing the series resistance decreased (ɳ, FF, Voc), and increasing the temperature reduced (ɳ, Voc, Jsc) and increased (FF).

The thermal energy properties in any material affect the substance’s capacity to store or transfer heat. This study investigated the effect of the polymeric chains’ tacticity on the thermal properties of polypropylene related directly to the thermal power, i.e., the heat capacity and thermal conductivity. The study selected different commercial polypropylene groups with two steric modes: isotactic and syndiotactic. The aim is to determine the parameters: isotacticity index, degree of crystallinity, glass-transition temperature, melting point, heat capacity, and thermal conductivity. The data were collected using gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC). The results showed that methyl groups randomly distributed within the homo-polypropylene changed the overall content of meso diads, i.e., less isotacticity index. The differences between isotactic and syndiotactic polypropylene groups were 20-40% the degree of the crystallinity, 5-10°C the glass-transition temperature, and 10-20°C the melting point. Using suitable mathematical models, these parameters can be related directly to specific heat capacity and thermal conductivity.

This paper suggested and created a proposed device for sensing an accurate distance from 5 to 400 cm with three sensors using the proposed on-line Feedforward Backpropagation Neural Network (FFBPN). Firstly, preparing a dataset (distances) with two distances utilizing Arduino and measured distance calculated from three sensors (2 ultrasonic and 1 IR). Secondly, target distances are calculated from the ground manually using a distance tape tool. Thirdly, interfacing Arduino and MATLAB using USB easily saved datasets from Arduino directly to MATLAB, then training, and testing data. The proposed device divides reading distances into three distances, getting from three sensors to get accurate distances. The first reading was 5-10 cm from down ultrasonic sensor 3. The second reading was 10-80 cm from middle IR sensor 2. The third reading was 80-400 cm from up ultrasonic sensor 1. The dataset was created and improved using the suggested FFBPN to create a very accurate distance gadget with three sensors. A suggested FFBPN consisted of 3 layers: The first input measured distance layer (from 3 sensors), the second hidden layer with ten neurons, and the third output layer distance. The numerical results showed that the proposed distance device was significantly accurate due to regression result R=1 using the proposed Neural Network (NN), which meanings that the device had 100% fitting. It had the best validation performance in 464 epochs, i.e., is 0.0036122. Furthermore, the proposed on-line FFBPN was fast because the training time equals three seconds. This distance device was implemented for use in robotic and radar applications to detect objects accurately because this device successfully detects near and far objects.

Parameter identification techniques for linear and nonlinear dynamic systems currently show a clear orientation toward black box models, with Artificial Neural Networks occupying a prominent place there. This paper presents a procedure for identifying linear dynamic systems parameters in two stages: in the first, a regressive model is fitted from the excitation and response time records, and in the second, its parameters are identified (matrixes of stiffness and damping) and dynamic characteristics (vibration frequencies and modes) based on the previous model. Artificial Neural Networks of the Adaline type and multilayer Perceptions are used for the first stage. The second stage is fully formulated through matrix algebra, which facilitates its systematic implementation and makes it independent of the complexity or dimension of the studied system. The proposed procedure is intended to operate from experimental records, so special attention is paid to the sensitivity of the results to the data interval and noise in the input signals. For the latter, various noise levels were incorporated into the correct responses obtained under ideal conditions, which respond to Gaussian distribution functions with a null mean and specified standard deviation. The proposed procedure justification, the results with the regressive models, and a study of the sensitivity of the results to the variation in the available data quality are presented.

The main objective of this research is to investigate the concrete cover thickness effect on the corrosion degree of the longitudinal reinforcing steel of short circular high-performance concrete columns. The practical program consists of casting and testing six circular columns with dimensions of (150 × 1000) mm tested under a central load. Three of them were reference columns, and three were corroded using an accelerated corrosion cell. The main variable adopted in the present research included the concrete cover thickness (10, 20, and 30) mm to compare results for weight and surface area loss of corroded steel and bearing capacity reduction among all samples. The results showed that increasing the concrete cover thickness from 10 to 20 and 30 mm decreased the loss percentage of the reinforcing steel weight by (12.47, 11.82, and 11.26) %, respectively. Also, the loss percentage of the cross-sectional area of the reinforcing steel decreased by (77.44, 64.00, and 57.75) %, respectively. While bearing capacity was reduced by (29.07, 25.25, and 32.23) % for 10, 20, and 30 mm clear covers, respectively, compared with the control columns of 10, 20, and 30 mm clear covers.

In this study, the fatigue life of aluminum alloys (7001-T6) was predicted with shot peening at various temperatures. Surface treatment with shot peening steel balls is a mechanism for reducing damage. An experimental investigation was conducted to find the degree of fatigue accumulation for AA7001-T6 under rotational bending loading and stress ratio R = −1. The experiments were conducted at RT (25 ℃), 330 ℃, and SP + 330 ℃ temperatures. A modified damage stress model that considers damage at various load levels was recommended for forecasting the fatigue life under high temperatures. The model and experimental results were compared to determine the most damage (Miner’s rule). The experimental results of the fatigue life indicated that the increased testing temperature reduced the fatigue life. However, using shot peening at high temperatures increased the fatigue life by 8% when loading sequence L-H and 10% when loading sequence H-L. The results showed a satisfactory degree of safety for the present model. Nevertheless, Miner’s model featured two models: one for low–high loading and high-low loading. The results were proper for prolonging fatigue life.

Several studies have shown that biopolymers improve soil; however, they mostly looked at how the shear strength and collapsibility improved without looking at how long the treatments would last. However, durability is an important factor that should be considered to get the most out of the treatment. This study investigates the durability and strength of gypseous soil enhanced by pectin biopolymer with periodic changes in wetting and drying. Soil with a gypsum content of 40% was mixed with 2% pectin biopolymer, and the samples were passed through successive wetting and drying cycles (1, 5, 10, and 15). The results indicated that periodic wetting and drying of pectin biopolymer-treated gypseous soil increased the shear strength of the soil until cycle 5, after which there was a slight and gradual decrease in strength until cycle 15 due to dissociation of pectin monomers under hydration and incomplete re-formation during re-drying, with a force decreasing by about 22% till ten cycles. Even beyond several cycles, some degree of strength and strength restoration could be observed. Also, the volumetric stability of the improved samples was clear until the last wetting and drying cycle.

Expired cement (EC) with fly ash can be recycled in artificial lightweight aggregates (ECFLA) manufacturing to manage industrial waste by mixing with fly ash through a cold bonding process, supplying a sustainable material and contributing to circular economy strategies to produce structural lightweight concrete. Four series of (ECFLA) were divided based on curing conditions and foaming agents, including 20 types of (ECFLA) with control mixes; air and water curing were compared, and their effects were investigated on the (ECFLA) properties. The present study identifies the optimum mix combinations. (EC) mixed with fly ash (FA) in varying amounts of 10, 20, 30, 40, and 50 % by weight of EC with and without foaming agent, it contained approximately 22% water by weight. The (ECFLA) was hardened through a cold-bonding air or water curing process for 28 days, followed by testing at different physical and mechanical properties. Particle crushing strength, impact value, specific gravity, and water absorption were tested on the hardened aggregates. The results indicated that it is possible to produce ECFLA from EC in a cold bonding process. The optimum kind of ECFLA was (20EC80FA) mixed with a foaming agent of loose dry density of 862.13 kg/m3, and particle crushing strength was 2.29 MPa at 28-day for 12 mm diameter. According to test results, cement content significantly affected (ECFLA) strength, consequently influencing lightweight structural concretes’ (LWC) compression strength. The highest 28-day compressive strength of LWCs was 42.3MPa for the (EC50FA50) mix.

Stabilization of problematic soil poses a significant challenge in civil engineering projects, especially in regions with prevalent soft clay soils. This study was carried out to study the impact of using a blend of reed ash and lime on improving and stabilizing problematic soil. A sample of soil was obtained from a location in the south of Iraq, specifically in Al-Muthanna Governorate. The treatment involved adding different proportions of reed ash (3%, 5%, 7%, and 9.0% of the soil's dry weight) along with 5% lime, which was determined as the optimal percentage based on previous research. Various laboratory tests were conducted to assess the characteristics of the treated soil, including compaction and unconfined compressive strength (UCS). The findings indicated a notable enhancement in UCS and the maximum dry density (MDD). It was observed that UCS and MDD increased with increasing the reed ash and lime mixture proportion, reaching an optimal level. Beyond this percentage, the strength started to decline. It was found that the incorporation of lime and reed ash (5% lime and 7% reed ash) into the treated soil significantly improved its strength, up to about 10 times compared to untreated soil after 28 days of curing. This approach offers additional benefits, such as reducing environmental pollution by decreasing CO2 emissions during phases of production and providing cost savings because of the affordability of the materials used.

This research examines the application of electrocoagulation (EC) by employing two water sources: river water and rejected water from a reverse osmosis system. To assess the impact of numerous factors on the removal efficiency of sulfate and iron, continuous flow experiments were conducted using bipolar and monopolar aluminum electrodes. The parameters studied included the number of electrodes (2, and 4) and flow rates (600, and 1000 L/h). The experimental findings revealed that increasing the number of electrodes improved the removal efficiency. Conversely, an increase in flow rate resulted in a decrease in removal efficiency for both water sources. For concentrated water, the best sulfate removal reached 47% (for four plates with 600L/h), whereas for the river, the highest sulfate removal was 50% (for four plates and a flow rate of 1000 L/h). For river water samples, the best iron removal was 56% (for four plates and 600L/h), whereas for concentrated water samples, the most significant removal was 79% (for four plates and 600L/h).

The present study demonstrates the effect of MgO nanoparticles concentrations on industrial wastewater treatment and electricity generation by microbial fuel cells. The MgO nanoparticles were prepared chemically using reflex methods by mixing magnesium hydroxide with ethanol. X-ray diffraction (XRD), Scan Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) were done for nanoparticle characterization. (Biological oxygen demand -BOD) and (Chemical oxygen demand - COD) were used as indicators to measure the acidity of wastewater. As a result, microbial fuel cells were proposed as a treatment method for wastewater. Nanoparticles with microbial fuel cell technology will always yield positive results in industrial water treatment. The results showed that using 0.025 mg/ml MgO nanoparticles in microbial fuel cells at pH 3 increased the COD degradation to (95.001%) through 30 min, BOD to (95.05%), and power voltage to (0.76) V. Therefore, treat the wastewater via microbial fuel cells were suggested. Nanoparticles with microbial fuel cell technology will always yield positive results in industrial water treatment.

The scarcity of measured hydrological data poses a challenge in many developing countries, stemming from insufficiently established gauging stations. Due to the mentioned issue, it is crucial to develop models capable of conducting reliable simulations of runoff behavior, particularly for ungauged catchments. Understanding the intricate relationships in rainfall-runoff modeling is essential for estimating peak flows, a critical aspect in formulating water resources management strategies, which can aid in water resource management and planning. In areas prone to floods performing, an extensive hydrological study becomes necessary. This study determined the outflow discharge at the outlet point of the Bessre Valley Ungauged Catchment (41.4 km2) using the Watershed Modeling System, used by reliable hydrological standards as a graphical interface integrating with the Hydrologic Modeling System (HEC-HMS). Bessre Valley watershed is one of the flood-prone watersheds in the Duhok governorate, mainly due to the terrain’s steep slopes at the upper north and east of the catchment. The catchment was delineated by a Geographic Information System (GIS). Its properties were extracted from a 12.5 m × 12.5 m Digital Elevation Model (DEM), which evaluates the hydrological response of a watershed to two significant storm events: a real rainfall event in March 2020 and a hypothetical 100-year return period event by dividing the watershed into ten sub-basins. Achieving a Nash-Sutcliffe efficiency of 0.895 indicates a high accuracy between observed and simulated peak flows of the real rainfall event of March 2020, underscoring the model's reliability for hydrological predictions. Also, comparing the HEC-HMS model and the Rational Method of (100 YRP event) for calculating peak discharges revealed a mere 2.2% error. Furthermore, the study explores the potential for building additional dams based on discharge volumes from specific sub-basins to enhance flood control and water storage capabilities.

Solar energy storage is essential in renewable energy systems, considering that solar energy is a periodic energy source that depends on time, so the intensity of solar radiation changes from time to time. Therefore, solar energy systems require storing energy to save it during the night periods or on cloudy days. The current solar heater designs are not feasible and ineffective unless energy storage is utilized (energy retention). The present research addresses improving the home solar water heater (SWH) performance under the atmosphere of Iraq. This study improves the thermal performance of a solar water heater integrated with a thermal storage tank using materials storing heat to achieve the most extended possible period of receding solar radiation. The SWH system performance was experimentally tested in Tikrit-Iraq. Several experiments were performed from 8:30 am to 16:30 hours in February 2022 with a water mass flow rate (\dot{m_w}) of (0.016 kg/s) for the circulation system and with a thermal load on the hot water tank (\dot{m_{th.L}}) of (0.0066 kg/s) for the two porous medium design cases (with and without solar reflectors). The results manifested that the maximum daily thermal efficiency (ηo) of the SWH system was 36.40% for design case 2 (with porous media and reflectors) at a (0.006 kg/s) thermal load compared to the case 1 (with porous medium and without reflectors) of 32.21%. At the same load, the outcomes elucidated that the overall thermal efficacy of the SWH regime in the convection presence provided the uppermost value utilizing porous media and reflectors. Also, the outcomes of the present investigation were compared with the preceding study, and the comparison outcomes were better than the present design circumstances.

The problem of sediments in dam reservoirs has negative effects on the life of dams and the associated financial costs for removing them from these reservoirs. This research is concerned with studying soil erosion in six valleys that flow into the Makhoul Dam reservoir and estimating the amount of sediment that will move into this reservoir annually. Three of these valleys (Al-Jirnaf, Umm Al-Shababit, and Al-Qasr) are located on the western (right) side of the reservoir, and the other three valleys (Al-Shook, Al-Rakhma, and Al-Fudha) are located on the left (eastern) bank of the reservoir. The sediments load expected to flow into the reservoir from these valleys were estimated by calculating the amount of soil erosion using the Universal Soil Loss Equation (USLE) and geographic information systems programs (GIS and Global Mapper) in addition to surfer program. Next, by figuring out the sediment delivery ratio (SDR), it was determined how much sediment load will be reached the reservoir from every valley. The results indicated that the total annual erosion of soil from these six valleys amounted to 1,010,677 tons, of which 249,175 tons are expected to reach the Makhul reservoir annually as a sediment load, divided as follows: Annual erosion from Al-Jarnaf valley is 518,700 tons, of which 121,467 tons reach the reservoir, at a rate of 48.7%. As for Al-Fudha valley, the annual erosion amounted to 232,198 tons, of which 54,692 tons reached to the reservoir, at a rate of 21.95%. The Umm al-Shababit valley occupied third place in terms of annual erosion 128,725 tons, of which 34,529 tons reached the reservoir at a rate of 13.85% of the total sediment load from the six valleys. Al-Shouk, Al-Rahma and Al-Qasr catchments came in fourth, fifth and sixth place, respectively. These catchments have annual erosion quantities of 52,299, 42,415, and 36,338 tons, and will contribute 14,901, 12,484, and 11,100 tons per year to the reservoir as a sediment load, which comes to 5.96%, 5.01%, and 4.45% for each of them, respectively.

One of the most important research projects in the recent years is strengthening structures. The significance of these studies was to modify the ability of buildings to withstand high loads without utilizing materials that hurt the environment. Six one-way ribbed slabs were experimentally tested in the present study to determine the effect of carbon fiber reinforcement polymer sheets on the structure. One of the specimens, used as a reference, was unstrengthen. Two specimens were strengthened with carbon sheets on 50% and 100% of the rib width. To prevent sheet debonding, two others used 50-mm-wide U-shaped strips. A complete rib wrap served as the final method of strengthening. All the specimens underwent concentrated load testing to investigate the ultimate capacity, deflection, stiffness, and ductility. According to the findings, all specimen’s deflection decreased in a ratio ranging from 4% in whole rib wrap to 46%. Also, the stiffness increased in all specimens, and the width of the carbon sheet insignificantly affected the stiffness, while the way of strengthening did. In the end, strengthening with 50% width has no discernible effect on the ultimate load (3%), whereas strengthening with 100% width raised by 41%, while adding U-shaped stripes increased the ultimate load capacity by 74% and completely wrapping the ribs increased by 132%.