a variety of composite steel-concrete column segments using shear connectors of different shapes and sizes to provide resistance to slip at steel – concrete interfaces . Hence , it represents a qualitative transition in the experimental and analytical investigations on shear connectors effectivity at steel – concrete interfaces , as most studies in the field of shear connectors were devoted to composite beam and slab – systems .
Three types of shear connectors – with four concrete grades for each type – were used in fabricating composite specimens . The twelve composite prototypes were subjected to push – out test individually to examine their behavior by measuring the slip values for each load incremental till failure , t
The present paper is an experimental study to improve the productivity of the conventional solar still. This done by modifying conventional still in a way that the distilled basin is larger than distillation basin, thus providing an increase in the condensation surface and speeding up the condensation process. Moreover, increase in the dimensions of the distilled base helps coupling reflective panels to the distilled base to reflect incident solar radiation to the distillation basin. For this purpose , two solar stills were made, one conventional designand another made according to the proposed design. The two solar stills were tested during the period from February to July 2009 under varying weather conditions of Basra, Iraq (latitude o
... Show MoreFatigue cracking is the most common distress in road pavement. It is mainly due to the increase in the number of load repetition of vehicles, particularly those with high axle loads, and to the environmental conditions. In this study, four-point bending beam fatigue testing has been used for control and modified mixture under various micro strain levels of (250 μƐ, 400 μƐ, and 750 μƐ) and 5HZ. The main objective of the study is to provide a comparative evaluation of pavement resistance to the phenomenon of fatigue cracking between modified asphalt concrete and conventional asphalt concrete mixes (under the influence of three percentage of Silica fumes 1%, 2%, 3% by the weight of asphalt content), and (chan
... Show MoreThe effect on aerodynamic drag of a truck by controlling the boundary layer separation using a rotating
cylinder on leading edge of the truck-trailer is investigated numerically. The flow was assumed to be steady, incompressible, turbulent, and two-dimensional passing over the top surface of the truck. The boundary condition for all the boundaries of the truck was set as well as the cylinder was treated as a moving wall with a specific rotational velocity. The developed computational algorithm is tested for the flow over a flat plate (8m) long with various free stream inlet relative velocity (U∞) which are considered the same as truck velocity and has the values (40, 60, 90, and 120) km/h. The effect of cylinder diameter (10,20,30,a
The influence and hazard of fire flame are one of the most important parameters that affecting the durability and strength of structural members. This research studied the influence of fire flame on the behavior of reinforced concrete beams affected by repeated load. Nine self- compacted reinforced concrete beams were castellated, all have the same geometric layout (0.15x0.15x1.00) m, reinforcement details and compressive strength (50 Mpa).
To estimate the effect of fire flame disaster, four temperatures were adopted (200, 300, 400 and 500) oC and two method of cooling were used (graduated and sudden). In the first cooling method, graduated, the tested beams were leaved to cool in air while in the seco
... Show MoreCohesive soils present difficulties in construction projects because it usually contains expansive clay minerals. However, the engineering properties of cohesive soils can be stabilized by using various techniques. The research aims to elaborate on the influences of using hydrated lime on the consistency, compaction, and shear strength properties of clayey soil samples from Sulaimnai city, northern Iraq. The proportions of added hydrated lime are 0%, 2.5%, 5%, 7.5% and 10% to the natural soil sample. The results yielded considerable effects of hydrated lime on the engineering properties of the treated soil sample and enhancement its strength. The soil's liquid limit, plasticity index, and optimum moisture content were de
... Show MoreZSM-5 zeolite was synthesis under hydrothermal conditions at 175oC. The synthesis parameters have been investigated to find optimum synthesis method. Firstly, the crystallization time has been investigated to find the optimum crystallization time. Also, the ageing time was studied. The morphology, structure, and composition of the synthesized ZSM-5 zeolite were characterized using scanning electron microscopy (SEM), pH meter, viscometer, and X-ray powder diffraction (XRD). The bulk Si/Al ratio of ZSM-5 zeolite was in the range of 9.5—11.7. The synthesized ZSM-5 zeolite with appropriate ageing time could adjust crystal size and degree of the crystallinity. The crystal size of ZSM-5 zeolite obtained at an agei
... Show MoreThe long-term monitoring of land movements represents the most successful application of the Global Navigation Satellite System (GNSS), particularly the Global Positioning System. However, the application of long term monitoring of land movements depends on the availability of homogenous and consistent daily position time series of stations over a period of time. Such time series can be produced very efficiently by using Precise Point Positioning and Double Difference techniques based on particular sophisticated GNSS processing softwares. Nonetheless, these rely on the availability of GNSS products which are precise satellite orbit and clock, and Earth orientation parameters. Unfortunately, several changes and modifications have been mad
... Show MoreCracks may appear in structures due to manufacturing processes and some time are appeared in the structure product from casting, these struetures may be used but in the life less than the design life according to crack propagation on it. In this research a thick cylinder has one crack or more is investigated to estimate the life under pulsation internal pressure. Finite element method with J-integral approach has been used to evaluate the numerical strain energy release rate (J) for the thick cylinder and the stress intensity factor (SIF J-integral method is most accurate method to evaluate the SIF for the elastic-plastic materiel by considering the local plastic zone near crack tip. Software developed using the FEM; J-integral; SIF and
... Show MoreIn this study, a simulation model inside a channel of rectangular section with high of (0.16 m) containing two rectangular obstruction plates were aligned variable heights normal to the direction of flow, use six model of the obstructions height of (0.059, 0.066, 0.073, 0.08 and 0.087 m) were compared with the flow behavior of the same duct without obstructions. To predict the velocity profile, pressure distribution, pressure coefficient and turbulence kinetic energy flow of air, the differential equations which describe the flow were approximated by the finite volumes method for two dimensional, by using commercial software package (FLUENT) with standard of k-ε model two dimensions turbulence flow.
... Show MoreSoil improvement has developed as a realistic solution for enhancing soil properties so that structures can be constructed to meet project engineering requirements due to the limited availability of construction land in urban centers. The jet grouting method for soil improvement is a novel geotechnical alternative for problematic soils for which conventional foundation designs cannot provide acceptable and lasting solutions. The paper's methodology was based on constructing pile models using a low-pressure injection laboratory setup built and made locally to simulate the operation of field equipment. The setup design was based on previous research that systematically conducted unconfined compression testing (U.C.Ts.). Th
... Show MoreIn this study; a three-dimensional model was created to simulate groundwater in Al-Haydariyah area of the governorate of Al-Najaf. A solid model was created to utilize the cross sections of 25 boreholes in the research region, and it was made out of two layers: sand and clay. The steady-state calibration was employed in six observation wells to calibrate the model and establish the hydraulic conductivity, which was 17.49 m/d for sand and 1.042 m/d for clay, with a recharge rate of 0.00007 m/day. The wells in the research region were reallocated with a distance of 1500 m between each well, resulting in 140 wells evenly distributed throughout the study area and with a discharge of 5 l/s, and the scenarios were run for 1000
... Show MoreAluminum Metal Matrix Composites (ALMMCs) was prepared by using stir casting technique for AA 7075 aluminum alloy as a matrix reinforced with SiC particles at various percentages (3, 6, 9 and 12 wt. % ) and 75µm in grain size. The prepared composite material can be used for many applications such as aerospace, automobiles and many industrial sectors. Abrasive wear test was carried out by two stages: the first stage was done by changing the emery papers at various grit sizes 180, 320, 500, and 1000µm with constant applied load 15N. While the second stage was carried out by changing the applied loads 5, 10, 15, 20 and 25N with constant emery paper at 320 µm grit size. Microstructure examination, hardness test and roughn
... Show MoreMembrane distillation (MD) is a hopeful desalination technique for brine (salty) water. In this research, Direct Contact Membrane Distillation (DCMD) and Air Gap Membrane Distillation (AGMD) will be used. The sample used is from Shat Al –Arab water (TDS=2430 mg/l). A polyvinylidene fluoride (PVDF) flat sheet membrane was used as a flat sheet form with a plate and frame cell. Several parameters were studied, such as; operation time, feed temperature, permeate temperature, feed flow rate. The results showed that with time, the flux decreases because of the accumulated fouling and scaling on the membrane surface. Feed temperature and feed flow rate had a positive effect on the permeate flux, while permeate temperatu
... Show MoreUncoupled behaviour of a dam undd, earthquake loading is investigated. Three constitutive models are used:. The linear-elastic model where soil properties; shear modulus and damping ratio are strains ar d cycle independent.-The equivalent linear model where soil properties are strain dependent but cycle independert. The shear modulus tends to decrease as the shear strain increases, while the damping ratio tends to increase as the shear strain increases. - A non-linear model where soil properties tend to change not only with shear strain but also with the progression of cycles. In this work, the bounding surface model is used.For these studies, three kinds of umerical integration methods in the time domain are usel. namely, Newmark, Wilso
... Show MoreSome of the newly constructed highway pavements in Iraq have shown premature failures with consequential negative impacts on both roadway safety and economy. Major types of these failures are permanent deformation (rutting) and cracking. Fillers were suspected to be a major contributor to these failures. The objective of this study is to evaluate the influence of new different fillers extracted from different local sources on the performance of asphalt mixtures. The effect of filler type and content on the failures potential of asphalt concrete as well as other mixes properties was investigated. A detailed laboratory study is carried out by preparing asphalt mixtures specimens using aggregate from Al-Taji quarry, (40-50) grade asphalt fr
... Show MoreAn investigation has been made into the effect of residual stresses on the vibration, characteristics of thin rectangular plates clastically restrained against rotation along three edges and free on the fourth edge .General frequency equation with and without including the effect of residual stresses has been obtained. Exact frequency expressions including the eflect of residual stresses for the cascs: S-S-S-F,S-S-C-F.C-C-S-F.C-S-S-F. C-S-C-F.C-C-C-F were also obtained. The eflect of the position of welding along the width of the plate for all cases was also included. Actual plate models were testea and the results were compared with the theoretical predictions giving good agreement
Thermal buckling analysis of symmetric and antisymmetric cross-ply laminated hybrid composite plates with an inclined crack subjected to a uniform temperature rise are presented in this paper. The first-order shear deformation theory in conjunction with variational energy method is employed in the mathematical formulation. The eight-node Lagrangian finite element technique is used for obtaining the thermal buckling temperatures of hybrid composite laminates. The effects of crack size and lay-up sequences on the thermal buckling temperatures for symmetric and a antisymmetric plates are investigated. The results are shown in graphical form for various boundary conditions. Finally, from this paper, the following main results have been found
... Show MoreAn iterative solution procedure necessarily involves pre- specified convergence criteria to stop teration. The Discrete Differential Dynamic Programming procedure to solve optimization problems formulated by the Dynamic Programming is an iterative solution procedure which, in its traditional form, involves two convergence criteria, namely, (a) and (B). The research used the optimum operation of an existing complex water resources system as a case study. The objective function was formulated as the maximum real monetary return. The formulated optimization model was run for a total of (194) different operation cases. Beside the traditional (a) and (B), seven new styles for a unique convergence criterion were examined in the solution. Consi
... Show MoreThis paper deals with prediction the effect of soil remoulding (smear) on the ultimate bearing capacity of driven piles. The proposed method based on detecting the decrease in ultimate bearing capacity of the pile shaft (excluding the share of pile tip) after sliding downward. This was done via conducting an experimental study on three installed R.C piles in a sandy clayey silt soil. The piles were installed so that a gap space is left between its tip and the base of borehole. The piles were tested for ultimate bearing capacity
according to ASTM D1143 in three stages. Between each two stages the pile was jacked inside the borehole until a sliding of about 200mm is achieved to simulate the soil remoulding due to actual pile driving. T
Surface water flow samples were collected with distances downstream over Saqlawiya main drain whose stretch of about 24.5 km. The drain travels through different land use pattern, before, flowing into Tigris River. Eight sampling points were carefully
selected downstream the channel during dry season. The examined water parameters were pH, NH3, NO3, PO= 4, BOD5, COD, TDS, S.S, Cl-, SO= 4, Na+ , Ca+2, Mg+2, and Oil and Grease. Descriptive and inferential methods through finding the best curve fit correlation were employed in the study to test the strength of the association between water chemical characteristics and distance downstream the channel. A comparison of the values of chemical parameters at the Al-Saqlawiya Drain-Tigris Riv
An experimental study was conducted with low cost natural waste adsorbent materials, barley husks and eggshells, for the removal of Levofloxacine (LEVX) antibacterial from synthetic waste water. Batch sorption tests were conducted to study their isothermal adsorption capacity and compared with conventional activated carbon which were, activated carbon > barley husks > eggshells with removal efficiencies 74, 71 and 42 % with adsorbents doses of 5, 5 and 50 g/L of activated carbon, barley husks, and eggshells respectively. The equilibrium sorption isotherms had been analyzed by Langmuir, Freundlich, and Sips models, and their parameters were evaluated. The experimental data were correlated well with the Langmuir model which gives the
... Show MoreThis research is concerned with performance of different shapes (parallel plate, grid, corrugated) and materials (polystyrene, polypropylene, P.V.C, and steel) of packing for an air -water- cooling tower. A Mechanical forced draught counter current flow cooling tower of 300 mm x 300 mm, cross-sectional area and 1.65m height was constructed and studied theoretically and experimentally Air flow rates of 0.533,1.035, and 1.774 kg/m2.s were used in conjunction with water flow rates of 1.686, 2.218, and 2.66 kg/m2.s, and water temperature of 40,45,50 °C. The tower characteristics (KG a Z/L) and the volumetric mass and heat transfer coefficients (Kça, hoa and ha) are found to be a function of the water and air flow rates simultaneo
... Show MoreThis paper presents the non-linear finite element method to study the behavior of four reinforced rectangular concrete MD beams with web circular openings tested under two-point load. The numerical finite elements methods have been used in a much more practical way to achieve approximate solutions for more complex problems. The ABAQUS /CAE is chosen to explore the behavior of MD beams. This paper also studies, the effect of both size and shape of the circular apertures of MD beams. The strengthening technique that used in this paper is externally strengthening using CFRP around the opening in the MD beams. The numerical results were compared to the experimental results in terms of ultimate load failure and displace
... Show MoreMany useful softwares in projects management are available now. Ms Project and Primavera are some
examples of these softwares. Those programs need to be fed by information by the user. The users
usually collect this information from the project and design documents. This collection process needs
considerable time and efforts, and usually accompanied of some errors in data transfer process.
In order to reduce the required time and efforts and to eliminate individual errors in data transfer
process, an Integrated System is needed. This Integrated System can extract the graphical information
from an AutoCAD drawing and transfer it to a digital form suitable for processing in the project
management softwares such as Exce
Computations of the relative permeability curves were made through their representation by two functions for wetting and nonwetting phases. Each function contains one parameter that controls the shape of the relative permeability curves. The values of these parameters are chosen to minimize an objective function, that is represented as a weighted sum of the squared differences between experimentally measured data and the corresponding data calculated by a mathematical model simulating the experiment. These data comprise the pressure drop across core samples and the recovery response of the displacing phase. Two mathematical models are constructed in this study to simulate incompressible, one-dimensional, two-phase flow. The first model d
... Show Moreعد تصاميم المساكن التقليدية في ريفنا العراقي مدرسة رائدة في تقديم نماذج وحلول تصميمية ناجحة ، ذلك لأنها نابعة من بيئة مجتمعنا الريفي والمتمثلة بظروفه الطبيعية وعاداته وتقاليده . تقوم فرضية البحث على اساس ان تصميم المسكن الريفي التقليدي قد تغير نتيجة لعوامل وظروف متعددة أهمها التطورات الحضرية للمدن والزاحفة باتجاه أقاليمها الريفية والتي غالباً ما تكون سريعة وعشوائية غير خاضعة للتخطيط المسبق، كما أن المسك
... Show MoreMost Internet-tomography problems such as shared congestion detection depend on network measurements. Usually, such measurements are carried out in multiple locations inside the network and relied on local clocks. These clocks usually skewed with time making these measurements unsynchronized and thereby degrading the performance of most techniques. Recently, shared congestion detection has become an important issue in many computer networked applications such as multimedia streaming and
peer-to-peer file sharing. One of the most powerful techniques that employed in literature is based on Discrete Wavelet Transform (DWT) with cross-correlation operation to determine the state of the congestion. Wavelet transform is used as a de-noisin
Buckling and free vibration analysis of laminated rectangular plates with uniform and non uniform distributed in-plane compressive loadings along two opposite edges is performed using the Ritz method. Classical laminated plate theory is adopted. The static component of the applied in- plane loading are assumed to vary according to uniform, parabolic or linear distributions. Initially, the plate membrane problem is solved using the Ritz method; subsequently, using Hamilton’s variational principle, linear homogeneous algebraic equations in terms of unknown are generated, the set of linear algebraic equations can be solved as an Eigen-value problem. Buckling loads for laminated plates with different combinations of bounda
... Show MoreExperiments were carried out to investigate natural convection heat transfer in an inclined uniformly heated circular cylinder . The effects of surface heat flux and angle of inclination on the temperature and local Nusselt number variations along the cylinder surface are discussed . The investigation covers heat flux range from 92 W/m² to 487 W/m², and angles of inclination 0° ( horizontal) , 30° , 60° and 90° (vertical) . Results show an increase in the natural convection as heat flux increases and as angle of inclination moves from vertical to horizontal position. An empirical equation of average Nusselt number as a function of Rayliegh number was deduced for each angle of inclination .