Abstract:This research studies the effect of high temperature which is reached to 600 °C onstructural lightweight and normal weight concrete. Lightweight concrete mix designedaccording to ACI committee 211-2-82 with mix proportion 1:1.12 :3.35 by volume .Thewc ratio equal to 0.5 by weight and cement content 550 kgm3. Mix proportions ofnormal weight concrete were 1:2:3 by weight with cement content 400 kgm3 and samewc. The design compressive strength at 28 days of normal weight concrete (NWC) andlightweight concrete (LWC) were 34.7 MPa and 22.62 MPa respectively. Compressivestrength tests were performed on 100 mm cubes exposed to high temperature 100,200,400and 600 °C. The normal weight concrete and light weight concrete test specimens wereexposed to high temperature for 10 minute suddenly at the required degree. Moreover,light weight concrete test specimens tested after graduate exposure to high temperaturereaching to the required degree with and without drying to examine the effect of moisturecontent.The results indicated that the structural lightweight concrete exhibits approximatelysimilar compressive strength loss compared to normal weight concrete up to 600 °C at 28days in graduate exposure .The percentage of reduction on compressive strength was30% in lightweight concrete compared to 28% in normal weight concrete at 600 °C .Insudden exposure to high temperature ,the opposite behavior was noticed .The percentageof reduction on compressive strength was 64.4% in lightweight concrete at 600°C .Drying of lightweight concrete specimens before graduate exposure to high temperaturessignificantly reduce the loss of compressive strength.
Recently, COVID-19 pandemic has swept the world left many victims as well as heavy casualties in the global economic system. As a result, governments have applied some necessary actions such as curfew and restricted mobility between cities, in order to control the spread of COVID-19 pandemic. However, these actions can decrease the traffic congestions within megacities leading to cleaner air and lower temperature. On the other hand, these actions have negative impacts on tourism in congested cities like Karbala and Najaf.Nowadays, urban climatic phenomena within holy cities have attracted researchers . The aim of this study is the evaluation of Urban Climate in term of temperature before and during COVID-19 pandemic period by using Landsat images and GIS techniques. Final findings showed a difference between Land surface temperature before and during COVID-19, which reached about 9 C° within built-up areas and bare lands. While this difference showed a relatively slight decrease within vegetated areas and waterbodies reached about 2 C°. This indicated that built-up areas and bare lands have been mainly affected by governmental restrictions during COVID-19 compared to other areas. Our analysis indicated that the temperature of the surface in urban areas has decreased during COVID-19 compared to the period before COVID-19. The proposed method can pave the way for planners and decision-makers to evaluate other holy cities in terms of the environment and recent disasters like the COVID-19 pandemic
The performance of the structural materials (concrete and steel reinforcement) and the behavior of the structural members after they were exposed to high temperatures have been considered the main topics of the current literature review. All varieties of concrete mixtures lost their compressive strength after 300˚C, even though there was no discernible strength loss between 150 and 300˚C. It was also discovered that the heating time had no appreciable impact on the strength loss when the exposed to heat less than 300 ˚C. Above 300 ˚C. Concrete begins to lose strength after being exposed for longer than one hour; the greatest loss of strength occurs during the first and second hours of exposure. Both the cured cement paste and the aggregates undergo chemical and physical changes at temperatures ranging from 600 °C to 900 °C. The 5% weighted rice husk ash (RHA) blended concrete still had an advantage in compressive strength, over the concrete when subjected to temperatures up to 700 C for two hours. Adding more recycled glass and ceramic particles to regular concrete increases its overall compressive and tensile strengths. Concrete becomes more durable and has fewer cracks when there is a higher replacement rate for ceramic and glass particles. The splitting tensile strength decreased with increasing temperature, changing from 60% to 70% of its initial strength after 600 °C. In this review, the better performance of concrete than the other concrete in terms of mechanical, physical, and durability properties at both room temperature and high temperature were concrete with 10% waste glass powder (WGP) substitution as a partial of cement and 10%–20% crushed glass (CG) substitution as a partial of aggregate .
Constructing and testing a microbial fuel cell, (MFC) was accomplished in this research. Two chambers MFC connected with salt bridge was operated and studied using synthetic and real wastewater as anode chamber solution. Operating temperature and pH value were investigated by changing temperature from 25 OC to 30 OC and varying pH from 6.7 to 6.5. The results reveled that increasing operation temperature had a significant effect on reducing operation time while decreasing pH improved the measured voltage and current besides reducing operation time to just five days. The cell was tested with the presence of real wastewater under the optimal temperature and pH and the results proved the capability of the manufactured cell in treating such contaminate in relatively short operation time. The COD reduction rate was above 60% indicated the ability of living microorganisms in digesting the wastewater producing electrical power with maximum values of 0.443 mV and 8.3 μ A for voltage and current, respectively.
Partial degradation of organic materials presented in sewage water had been conducted in the current research in a simulated sewer system. The process had been improved by aeration and seeding with activated sludge to reveal the effect of increasing the amount of biomass in the system. Three ambient temperatures were conducted as 10, 20, and 30 OC to display the influence of temperature on the degradation process. The results revealed that adding activated sludge to the system in a ratio of 50/50 (v/v) had a significant influence on the degradation as more microorganisms required more organic nutrients. In the other hand, increasing the operating temperature indicated positive influence in terms of soluble chemical oxygen demand (SCOD) removal as temperature motivated the living biomass towards severe degradation.
The main objective of this study is to evaluate the comparative performance of three artificial neural network techniques (radial basis functions “RBF”, multilayer perceptron “MLP”, and group method of data handling “GMDH”) based approach with the Penman–Monteith “PM” method for determining the group reference evapotranspiration “ET0” on monthly basis in Basrah City, south of Iraq. Climate information extends over 22 years (1991- 2012), monthly records of maximum temperature (Tmax), mean temperature (Tmean), minimum temperature (Tmin), wind speed (U) and relative humidity (RH) are used in this research. The architecture of artificial neural network models is performed during the process of training. The efficiency of trained model is checked by using the testing data, which is not used in the process of training. The evaluating of the artificial neural model performance is carried out by using cross-validation, a set of rows for each validation fold is determined randomly after stratification on the target variable “ET0”. Various set of climate inputs variables are used for creating nine artificial neural network models. The efficiency of artificial neural network models with two predictor variables (Tmean & U) for simulating ET0 is highly efficient according to the evaluation criteria. There is a significant improvement in the results of all artificial neural network models when using three input combination variables (Tmean, U, & RH) compared with the models that have only two-climate variables. Artificial neural network models especially (RBF, MLP, and GMDH) are efficient and powerful techniques for simulating ET0.
Microbial-induced carbonate precipitation (MICP) is a fast-evolving technology for cementing sandy soils, improving ground, repairing concrete cracks, and remediating contaminated land. The current work thoroughly reviews various factors that can impact the effect of the MICP technology on geomaterials. These factors include the type and strain of the microbes, concentration of bacterial solution, cementation solution composition and concentration, environmental factors (temperature, pH level, and oxygen dissolved), and soil properties. It was found that the type and strain of bacteria, concentration of bacterial suspension, pH value, temperature, and the reaction solution properties are the most affecting factors in controlling the characteristics of the produced calcium carbonate, which in turn affects the degree of bonding between geomaterials particles. For an optimal implementation of the MICP in soils treatment, it appeared that for the most commonly used bacterial strains a temperature between 20 and 40 °C, a pH between 6.5 and 9.5, and a cementation solution concentration of 0.5 mol/L, are typically recommended.
Asphalt pavement temperatures were estimated at surface and depth of 50 mm. Differences between estimated maximum surface temperatures and maximum air temperatures were found to be remarkably high, whereas the minimum surface temperatures were slightly different from minimum air temperatures. Different studies showed that the maximum pavement temperatures at depth (50 mm) were less than that of the maximum surface temperatures, whereas, minimum pavement temperature at the same depth showed slightly higher readings than that of the minimum surface temperatures.Algorithms that discussed in this research work found to produce remarkably different estimations of depth temperatures. The undergoing research work aims to cast light on the performance of these models in terms of data regarding Anbar province of Iraq.
Abstract :- For improving the properties of asphaltic cement several materials such as sulfur, rubber, carbon black, polymers….etc. are used for this purposes. In this study low density Polyethylene (LDPE) used at different percentage (0%, 1%, 3%, 5% and 7%) by weight of the asphaltic cement and then the changes in the properties are evaluated by pentration test (ASTM D-5), softening point test (ASTM D-2398), and Kinematics viscosity test (ASTM D-2170). Temperature susceptibility was evaluated by using Penetration vescosity number ( P.V.N ). In addition to that stiffness modulus of asphalt cement was predectied by using van der pole’s nomograph. The study showed that the LDPE increase the hardening of asphalt cement at different percentage except at (1%), and decrease the susceptibility of asphaltic cement to temperature.
Chlorine is considered as one of the most important disinfectants because of its availability in a wide form and in acceptable cost. Measurements of residual chlorine are very essential to assure the presence of disinfection at various locations of the water distribution system. The aim of the present work is to find the residual chlorine concentrations in potable water which leaves Tikrit University water supply plants. pH-, water temperature and water turbidity are also measured. Sixty samples of tap water are tested during November 2009 till April 2010. The results show that range of residual chlorine is 0.2-4mg/l) and most of the measured values are higher than the maximum permissible limit according to Iraqi standards( 417/1974 ) The data indicated that pH is within the range of (7-8.2) and there is no clear relationship between pH and residual chlorine concentration. It is found that there an inverse proportionality between residual chlorinean and temperature . Same trend is found between residual chlorine and turbitiy. The Conductivity and total dissolved solid of drinking water was within the permitted level by the Iraqi standers
AbstractThis work presents the study of water flow through a packed bed containing spherical glass particles distributed randomly. The packed bed was 7.62 cm in diameter and 57 cm long. The glass particles were 0.42, 0.50, 0.61, 0.79 and 1.01 cm in diameter. Different flow rates of fluid were used which expressed by modified Reynolds number. The experiments were carried out at laboratory temperatures at city water temperature (25◦C) for water flow. Many variables were studied in this work such as fluid type, flow rate and the packing porosity, in order to study the effect of these variables on the pressure drop and friction factor. The results showed that the pressure drop through a packed bed is highly sensitive to the packing porosity which has a significant effect on the friction factor. It was found that as the bed porosity increases the friction factor values as well as the pressure drop values decrease.Empirical correlation for friction factor as a function of Reynolds number for water flow through packed of mono size packing has been made, and can be written as follows: The correlation coefficient was 0.97406 and percentage of average errors was 2.44%.
This study is conducted to investigate the strength and stiffness of clayey soil stabilized with fly ash-based geopolymer for unpaved roads. Two sodium hydroxide concentrations of 6 and 8M and two alkali solution ratios of NaOH:Na2SiO3= 1 and 1.5 were considered. Other factors such as fly ash replacement ratio (by mass), curing period, and curing temperature were held constant at 15%, 48 hours, and 65 C, respectively. The unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests were performed to evaluate the mixtures. Outcomes of this study revealed that the strength of the clayey soil could be increased by up to 94%. Additionally, increasing sodium silicate content in the alkali solution increased the solution's activity and yielded higher strength and stiffness. This study confirms the effectiveness of the geopolymer binder for the improvement of soil strength and stiffness.
This study concern with a new technology to modified the compressive strength of the thermo brick which have a main role in construction field. This research using a new local cheap additives called (tar) which is available in Iraq (Kirkuk area). The experimental program have include three type of thermo brick available in local market (Iraqi, KSA, and Kuwaiti) and these type are common used in south area of Iraq especially Basrah City. The sample has exposed to the steam of tar in different temperature. Four affecting factor are studied carefully on compressive strength of brick including, tar , brick manufacture type, number of exposing faces of brick, and the age of brick after finishing expose of brick to the tar steam. The result shows maximum compressive strength conducted are 4.4 MPa when two faces expose to tar and two hours’ time of exposing ( one hour for each face) and the modified percentage was 62% compared with reference sample (KSA type). The improvement in compressive strength of Iraqi type and Kuwaiti were 27% and 45% respectively. Furthermore the improvement of compressive strength with same condition aforementioned but for one hour exposing time (half hour on each face) are 37.5%. The chemical properties also has conducted in this study.
Wadi Houran is one of the largest valleys in Iraq. Although it is discharging billions of rainfall water over/during many years to Euphrates river, it's almost devoid of agricultural investment. The current study aims to focus on this important valley water resource and study the possibility of constructing a series of small dams to store rainfall water and planting forestry and establishing a natural reserve that is able to sustain and improve ecology system. Target area of 4000 km2 is selected in the midstream of the valley. In general, it is about one billion m3 of rainwater flowing to Euphrates River during some years with yearly average values about 400 Mm3. Four dams were constructed to store about 46 Mm3 of rainwater. It is possible to construct small-dam-series of optimal height and location to expand the rainwater harvesting and groundwater recharging. A Current study was done and aimed to establish of oases and natural reserves in order to improve climate conditions, minimize the dust and CO2, mitigation of summer high temperature and decrease the soil erosion due to torrents. This study recommended constructing 13 optimal height dams that store about 303 Mm3 of water, and increase the water surface area of reservoirs in this valley from 15 to 90 km2which leads increase the water volume that is recharging ground water from 4.7 Mm3 to 28 Mm3 per year.
Hydrodynamic modeling of viscous flow in porous media was investigated for fourselected filter media crushed silica, crushed anthracite coal, glass beads and crushed garnet.Typical constants that can be used to estimate head loss for some of the most common designof granular media filters were correlated. The effect of several parameters such as porosity(35%-60%) , temperature(20oC-80oC) and media grain size (0.5-2mm) was studied. Empiricalrelationships were developed using a plot of friction vs. Reynolds number similar to those thathad been successfully used for the flow of fluids in pipes. Analytical models were made todevelop an equation for viscous turbulent flow in porous media from first hydraulic principles.Empirical equation was developed to predict pressure drop in porous media as a function ofbed porosity and evaluated the friction factor as a function to flow type.
The object of this paper was reduced the heat transferred quantities from or to internal building space by covering it's external walls with many materials, therefore, the researcher build the (1x1x2) m room sample at 3rd floor for building in Baghdad city (L = 33.2 N°), and (1x2)m wall has East orientation , while the other surfaces were insulated by 200 mm styropor sheets, and using Air – Conditioner 0.5 Ton of refrigeration to afford the standard thermal comfort. The researcher found that, the metal sheet painted with thermal plastic paint with 10 mm thermal insulation used as a cover layer for ordinary wall saved 57% from electrical energy consumption in Air-Conditioner, while used that material without insulation layer gives 46.2% , hollow plastic board (for decorative used) gives 42.5% , hollow faced brick with thermal insulation gives 40.22%, solid flooring brick with thermal insulation gives 39.5% , colour metal sheets with air – gap gives 36.4%, asbestos – cement board coated by reflective aluminum paint gives 34%, the ceramic with thermal insulation gives 31.9%, while all the material – marble , porcelene , hallan stone , fiberglass sheets with 10 mm thermal insulation will gives the electrical energy reduction percentage less than 30% .
This study is the second stage of the paper “Study the Effect of Rubber Silicon on Physical Properties of Asphalt Cement”. This study took the effect of additives on asphalt mixture performance. Asphalt mixture has been designed by Marshall method for determining the optimum asphalt content and geophysics properties of mix according to ASTM (D- 1559 ). Rubber silicon at different percentage (1%, 2%, 3% and 5%) was added to asphalt binder and three specimens of asphalt rubber silicon mixture (ARSM) are prepared and evaluating according to Marshall method. Diametric tensile creep test ASTM (D-1075) at 60 Co used to evaluating permanent deformation and modulus of elasticity for ARSM. The study shown that the Rubber-Silicon has more effects increasing the marshal stability, air voids, and reducing the flow and bulk density compared with the original mix.. Increase the flexibility properties of the mix and this appear from reducing the permeate deformation at test temperature (60C), the reduction percent is about (30 to 70)%
AbstractIn this paper a nonlinear finite element analysis is presented to simulate the fire resistance of reinforced concrete slabs at elevated temperatures. An eight node layered degenerated shell element utilizing Mindlin/Reissner thick plate theory with initial stiffness technique is employed. The proposed model considered cracking, crushing, and yielding of concrete and steel at high temperatures. More complicated phenomena like concrete transient thermal strain and concrete spalling are excluded in the present analysis. The validation of the proposed model is examined against experimental data of previous researches and shows good agreement.Keywords: Fire resistance, Material nonlinearity, Reinforced Concrete Slabs
Organic soils are problematic soil for various engineering applications due to their high compressibility and low shear strength which need to be improved. For many soil improvement techniques, using waste materials, such as fly ash (FA), is a practical and sustainable process. In this research, FA and geopolymer were used e used to reduce organic soil's compressibility. A one-dimensional consolidation test was performed to evaluate the organic soil's consolidation and compressibility properties. The geopolymer was prepared using 20% FA and of sodium hydroxide ratio and sodium silicate alkali solutions. The geopolymer specimens were first cured for 2 hours at 45 and 65 oC, then cured for further 28 days at room temperature. The consolidation test results showed that FA-based geopolymer is effective in stabilizing organic soils due to the observed improvement in the compressibility, consolidation, and permeability characteristics. The compression index decreased by 98.16%, and the permeability decreased by 95%.
The paper shows the final findings of the effect of metakaolin on the strengths properties of concrete exposed to crude oil. Sulfate resistance Portland cement of V type was used and specimens of concrete were adjusted and subjected to a solution of concentrated crude oil. However, the samples are cured in a control media at immersion ages of (28, 56 & 120 days) with ambient temperature, then samples have been kept in curing water for comparisons purpose as well. The results explain that the use of metakaolin reinforces compressive, flexural and splitting resistance of concrete which is exposed to crude oil. The compressive strength reduction increased from 8.0% at (28 days) to 37.7% at (120 days) curing for normal weight concrete (NW) whereas the concrete incorporating metakaolin (MC) has a reduction of 6.0% at (28 days) & 29.3% at (120 days). .
To classification groundwater quality in the study area, three wells were drilled at a depth of 10m and selected two locations across Al Warrar Canal to represent their water quality. Water samples were collected from these wells and the Warrar Canal to examine water quality. Then results were compared against the World Health Organization (WHO) limits to study the Index of Water Quality (WQI). WQI was calculated according to the Canadian Council of Ministers of the Environment (CCME), and the quality of water was evaluated for domestic and irrigation uses. The samples were tested for electrical conductivity, pH, temperature, total dissolved solids, chloride, total hardness, nitrate, and alkalinity according to the standard methods. The results of laboratory analysis showed significant differences among the wells and Warrar Canal water quality in the measured parameters according to WHO limits. Due to many human activities like urbanization, agrarian overflow, drainage of untreated sewage, and industrialization, high values of trace elements and heavy metals were recorded in wells three. For agriculture purposes, the results show that the water in the three wells is very high salinity, where the Warrar Canal is high salinity, and Canal water causes saline and alkali damages. It was recommended that the WQI in three wells was poor water quality whereas, marginal water quality was pointed in AL Warrar Canal.
AbstractThe crystalline zeolite, namely faujasite type Y with SiO2/Al2O3 mole ratio of 5 was used as raw material for preparation of isomerization catalysts. Decationized HY-zeolite was prepared by treating Na Y-zeolite with solution of 4N ammonium chloride through ion exchange, drying at 110°C, and calcination initially at 150°C and the temperature increased to 525°C with a rate of 75°C/h to liberate NH3 and water. Then, HY-zeolite was reduced with hydrogen at 380°C, then fabricated as a spherical shape and calcined at 400°C.A 0.5 wt % Pt/HY-zeolite catalyst was prepared by impregnation with chloroplatinic acid. The catalyst was dried at 110°C over night, calcined at 400°C and reduced with hydrogen at 380°C. The prepared catalyst powder was then formulated as a spherical shape with 20% sodium silicate. The decationized HY-zeolite was treated with HCl, HNO3 and HI promoters using different normalities and with different concentrations of Sn, Ni and Ti promoters by impregnation method to obtain acidic and metallic promoters' catalysts, respectively. A 0.5 wt% of Pt was added to above catalysts using impregnation method. The catalysts were then dried, calcined, reduced and formulated using the same steps in preparation of Pt/HY-zeolite catalyst.