In order to design structures on soft soils, it is necessary to predict the behavior of the soft soil
under imposed structure load. The high excessive settlements of the soft soil can cause many
problems for the structures built on the soil like cracking and breakup of pavements, railway,
highway embankments, etc...
In this work, the finite element method is utilized as a tool for carrying out different
analyses of embankments on soft ground with different conditions. The computer program CRISP
(CRItical State Program) is developed to suit the problem requirements. CRISP uses the finite
element technique and allows predictions to be made of soil deformations using the critical state
theory.
Eight-node isoparame
A cantilevered piezoelectric beam with a tip mass at its free end is a common energy harvester configuration. This paper introduces a new principle of designing such a harvester which increases the generated voltage without changing the natural frequency of the harvester: The attraction force between two permanent magnets is used to add stiffness to the system. This magnetic stiffening counters the effect of the tip mass on the natural frequency. Three setups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle. Theoretical and experimental results show that magnetically stiffe
... Show MoreDarcy-Weisbach (D-W) is a typical resistance equation in pressured flow; however, some academics and engineers prefer Hazen-Williams (H-W) for assessing water distribution networks. The main difference is that the (D-W) friction factor changes with the Reynolds number, while the (H-W) coefficient is a constant value for a certain material. This study uses WaterGEMS CONNECT Edition update 1 to find an empirical relation between the (H-W) and (H-W) equations for two 400 mm and 500 mm pipe systems. The hydraulic model was done, and two scenarios were applied by changing the (H-W) coefficient to show the difference in results of head loss. The results showed a strong relationship between both equations with correlation coefficients of 0.999,
... Show MoreImplementation of Warm Mix Asphalt concrete (WMA) is getting global acceptance due to the restrictions for protecting the environment and the requirements to reduce fuel consumption. In this investigation, two WMA mixtures have been prepared in the laboratory using medium curing cutback (MC-30) and Cationic emulsion asphalt. Hot Mix Asphalt (HMA) was also prepared for comparison. The cylinder specimens (63.5mm) in height and (101.6mm) in diameter were constructed from the mixtures and subjected to indirect tensile strength test to determine the Tensile Strength Ratio (TSR). The cylinder specimens of (101.6mm) in height and (101.6mm) in diameter were also constructed from those mixtures and subjected to static compressive
... Show MoreThe uniform flow distrbiution in the multi-outlets pipe highly depends on the several parameters act togather. Therefor, there is no general method to achieve this goal. The goal of this study is to investigate the proposed approach that can provide significant relief of the maldistribution. The method is based on re-circulating portion of flow from the end of the header to reduce pressure at this region . The physical model consists of main manifold with uniform longitudinal section having diameter of 152.4 mm (6 in), five laterals with diameter of 76.2 mm (3 in), and spacing of 300 mm. At first, The experiment is carried out with conventional manifold, which is a closed-end. Then, small amount of water is allowed
... Show MoreThis paper is aiming to develop a numerical procedure using the finite element method for the
analysis of soil consolidation by taking into consideration the loading and unloading cycles with
particular emphases on the pore pressure built up. The study is concerned with trapezoidal cyclic
loading. The shear stresses that are developed in the subsoil due to cyclic loading cause shear strains
and change in the mean normal stresses due to distortion of soil element. Biot’s consolidation theory
that adopted in this study may be able to take these changes into consideration. The results indicated
that the excess pore water pressure increases with load cycles and finally, a steady state conditions are
reached. This may b
Kerberos system is a powerful and widely implemented authentication system. Despite this fact it has several problems such as the vulnerability to dictionary attacks which is solved with the use of public key cryptography. Also an important security feature that is not found in Kerberos is perfect forward secrecy. In this work the lack of this feature is investigated in Kerberos in its original version. Also a public key based modification to Kerberos is presented and it is shown that it lacks the prefect forward secrecy too. Then some extensions are proposed to achieve this feature. The extensions are based on public key concepts (Diffie-Hellman) with the condition of keeping the password based authentication; this requires little modif
... Show MoreDetermining the aerodynamic characteristics of iced airfoil is an important step in aircraft design. The goal of this work is to study experimentally and numerically an iced airfoil to assess the aerodynamic penalties associated with presence of ice on the airfoil surface. Three iced shapes were tested on NACA 0012 straight wing at zero and non-zero angles of attack, at Reynolds No. equal to (3.36*105). The 2-D steady state continuity and momentum equations have been solved utilizing finite volume method to analyze the turbulent flow over a clean and iced airfoil. The results show that the ice shapes affected the aerodynamic characteristics due to the change in airfoil shape. The experimental results show that the horn iced airfoil
... Show MoreMonitoring and analysing of the vertical deformations or the settlements of the structures is one of the main research fields in geodetic applications, which is considered a precise periodic measurement, made at different epochs to investigate these deformations on heavy structures.
In this research, the deformation measurements were carried out on one of Baghdad University buildings,” Building of Computers Department” of dimensions (70.0 * 81.3 m.). Due to some cracks observed in their walls, it was necessary to monitor the vertical displacement of this building at some particular monitoring points by constructing a vertical network and measured in different epochs. The first epoch (zero epoch) was carried out in April 2006, the
Heat transfer process and fluid flow in a solar chimney used for natural ventilation are investigated numerically in the present work. Solar chimney was tested by selecting different positions of absorber namely: at the back side, front side, and at the middle of the air gap. CFD analysis based on finite volume method is used to predict the thermal performance, and air flow in two dimensional solar chimney under unsteady state condition, to identify the effect of different parameters such as solar radiation. Results show that a solar chimney with absorber at the middle of the air gap gives better ventilation performance. A comparison between the numerical and previous experimental results shows fair agreement.
For many years, the construction industry damages have been overlooked such as unreasonable consumption of resources in addition to producing a lot of construction waste but with global awareness growth towards the sustainable development issues, the sustainable construction practices have been adopted, taking into account the environment and human safety. The research aims to propose a management system for construction practices which could be adopted during constructing different types of sustainable buildings besides formulating flowcharts which clarify the required whole phases of sustainable buildings life cycle. The research includes two parts: theoretical part which generally ,handles the sustainability concepts at construction i
... Show MoreSingle phase AC induction motors are one of the widely used motors in the world, yet relatively little woke has been done in the applications of power electronic converter to these motors to achieve variable speed operation. When variable speed is required, it is usually achieved either by using auto transformer or by switching between two or more fixed winding configurations. The motor is analyzed as an unbalanced two phase system to determine the torque that can be expected under variable frequency control.
The performance of capacitor-run single phase induction motor used in SHEPWM adjustable speed drives in the steady-state is investigated. The supply voltage-frequency law for the motor is selected in such a way as to insure a cor
يعتمد جزء من تطور المجتمعات على مدى قدرتها وقابليتها على التلاؤم مع التغيرات اللازمة والمستمرة لتطوير استجابتها مع البيئة المناخية
المحيطة بها، وقد كان للتطور التكنولوجي الأثر المباشر على هذا المفهوم وأهمية توجيهه بالإتجاه الصحيح لأبنيتنا وبصورة تتواءم مع المتغيرات
المناخية المحلية.
ونظرًا لقلة الدراسات التي تركز على أهمية تكاملية البيئة المناخية مع التكنولوجيا المعاصرة وبما ينسجم مع الواقع المحل
The continuous and rapid development of shapes for architectural members and structural researches development in stability field encourage the designers and researchers to study the effect of member shape on the load capacity. The optimum strength of compression members with economical dimensions can be obtained to satisfy the architectural and technical requirements. A
different nonlinear tapered member shapes have been studied under compression axial force with simply supported end conditions. Then graphical comparisons for different member shapes are presented to find the maximum axial force and minimum member volume at buckling state. This study is based on modified stability functions that have been based on Bessel functions. T
The vortex rate sensor is a fluidic gyroscope with no moving parts and can be used in very difficult
conditions like radiation, high temperature and noise with minimum cost of manufacturing and
maintenance. A vortex rate sensor made of wood has been designed and manufactured to study
theoretically and experimentally its static performance .A rig has been built to carry out the study,
the test carried out with three different air flow rates (100, 150, and 200 l/min).The results show that
the relation between the differential pressure taken from the sensor pickoff points and the angular
velocity of the sensor was linear.The present work involved theoretical and experimental study of
vortex rate sensor static characteri
A general velocity profile for a laminar flow over a flat plate with zero incidence is obtained by employing a new boundary condition to the other available boundary conditions. The general velocity profile is mathematically simple and nearest to the exact solution. Also other related values, boundary layer thickness, displacement thickness, momentum thickness and coefficient of friction are nearest to the exact solution compared with other corresponding values for other researchers.
This study aims to derive a general relation between line loads that acting on two-way slab system and the equivalent uniformly distributed loads. This relation will be so useful to structural designer that are used to working with a uniformly distributed load and enable them to use the traditional methods for analysis of two-way systems (e.g. Direct Design Method). Two types of slab systems, Slab System with Beams and Flat Slab Systems, have been considered in this study to include the effect of aspect ratio and type of slab on the proposed relation. Five aspect ratios, l2/l1 of 0.5, 0.75, 1.0, 1.5 and 2.0, have been considered for both types of two-way systems.
All necessary finite element analyses have been executed with SAFE Soft
Stripping is one of the major distresses within asphalt concrete pavements caused due to penetration of water within the interface of asphalt-aggregate matrix. In this work, one grade of asphalt cement (40-50) was mixed with variable percentages of three types of additives (fly ash, fumed silica, and phosphogypsum) to obtained an modified asphalt cement to resist the effect of stripping phenomena .The specimens have been tested for physical properties according to AASHTO. The surface free energy has been measured by using two methods namely, the wilhelmy technique and the Sessile drop method according to NCHRP-104
procedures. Samples of asphalt concrete using different asphalt cement and modified asphalt cement percentages(4.1,4.6 an
The work aims to calculate pollutants gases concentration that are emitted from gasoline
engine Vehicles exhaust .These concentration are compared with emission limits in other
countries. These gases are carbon monoxide (CO), unburned or partially burned hydrocarbons
(HC), nitrogen oxides (NOx), lead oxides, particulate matter and soot. The research is carried out on a new and old cars .which are widely used in Iraqi roads .these cars are different in product year , distance travelled and in Exhaust- gas treatment techniques which used. The analysis of exhaust gases carried out by using the electronic exhaust gas analysis system (T156D). Which is maunfactured in Italy and operate with windows system. The results show decre
Reconstruction in Iraq requires coherent legitimate frameworks that are able to detail obligations, rights and responsibilities of the parties participating in reconstruction projects, regardless their type or delivery system.
Conditions of Contract can be considered an important component of these frameworks. This paper investigates flexibility and appropriateness of the application of Iraqi conditions of contract in reconstruction projects. These conditions were compared to FIDIC Conditions. The objective wasn't comparing individual clauses, but rather exploring the principles and philosophy laying behind each conditions, and to what extent each conditions care about realizing equity between main contract parties. Validity of applic
A genetic algorithm model coupled with artificial neural network model was developed to find the optimal values of upstream, downstream cutoff lengths, length of floor and length of downstream protection required for a hydraulic structure. These were obtained for a given maximum difference head, depth of impervious layer and degree of anisotropy. The objective function to be minimized was the cost function with relative cost coefficients for the different dimensions obtained. Constraints used were those that satisfy a factor of safety of 2 against uplift pressure failure and 3 against piping failure.
Different cases reaching 1200 were modeled and analyzed using geo-studio modeling, with different values of input variables. The soil wa
The problems of design of machine foundations for the special case of vertical mode of vibration
for block foundation are presented in this paper. The empirical design method is used to get the
results using a computer program MATHCAD dealing with the parameters related to the machine.
Design charts that are prepared to be a guide for the designer engineer are drawn. The design charts
are based on the variables limitations including the properties of the soil, machine and foundation.
The design charts are based on three displacements which are acceptable for design of the machine
foundation.
The Shatt Al-Arab River, in southern Iraq, flows southeastwards through Basrah City to the Arabian Gulf. Seven creeks are branched off the river: Jubyla, Muftya, Robat, Khandek, Ashar, Khora, and Saraji, where they are affected by tidal phenomena. The change in the hydrological status of the river over the last decade has adversely affected the quality of the river's water. Urban sewage and industrial wastewater are usually discharged directly or indirectly into the river. The entire river's course is studied, starting at the point where the Tigris and Euphrates rivers meet in the Qurnah district and extending into the vicinity of the river's estuary. The use of the Shatt Al Arab River in modelling a planned regulator on
... Show MoreThis article demonstrates how different cooling rates and precipitation hardening affected the mechanical properties of AA2024. Three impact test samples were chosen. Solution heat treatment was conducted at 500 °C for 2 hrs., followed by quenching in three different quenching media (Sunflower Oil, Sesame Oil, and Corn Oil). As a result, the Sunflower Oil showed the lowest shock absorption rate; hence, it was chosen as the quenching medium for this study. Consequently, all samples of tensile, hardness, and impact tests were solution heat treated at 500 °C for 2 hours, then quenched in Sunflower Oil to room temperature and artificially aged at temperatures of 180°C for 1,2,4 hour, 195°C for 1, 2, 4 hour, and 210°C fo
... Show MoreThe governing differential equations about the seepage were resolved using the standard numerical. The research location was on the Darbandikhan dam, which is about 230 kilometres northeast of the governorate of Baghdad in the district of Sulaymaniyah on the Diyala River. The Geo-Studio program and its subprogram SEEP/W were used to examine the total water head through the dam and water flux, and exit gradient through the numerical model that represents the dam body to show how seepage affects the dam's stability. To run the dam numerical model, three upstream reservoir water levels at a Minimum water level of 434 m, Normal water level of 472 m, and flood water level of
... Show MoreClimate change poses a global challenge with profound repercussions on land cover, particularly affecting areas like Iraq due to decreased rainfall, rising temperatures, desertification, vegetation loss, and reduced river tiers attributable to weather change. This study investigates the impact of climate change on land cover in the Al-Hillah district of Babil province, Iraq, using remote sensing data and satellite imagery from Landsat 5 and 8 through the website of the US Geological Survey from 1995 to 2021. ArcMap 10.8 software program was employed to analyze and visualize these changes. The Al-Hillah district spans an area of 878 km2, encompassing built-up areas, agriculture areas, desert land, wetlands, and
... Show MoreConstruction is a complicated process that takes place in an almost uncontrollable environment. Although projects can be carefully planned in advance in principle, there is a chance that unforeseen events and crises can disrupt these plans, affecting project development. Because the initial investment expenditures in construction projects are so large, they may be quickly influenced by crises, resulting in significant financial losses. The 2014 financial crisis was one of the most prominent crises that Iraq faced, which significantly impacted various activities in general and the construction industry in particular. Despite the importance of crisis management systems, the researchers found a great lack of local studies l
... Show MoreThe research represents an applied study to the urban scene of Baghdad city center within the area of (Al Bab Al Sharqi – Al Tahrir Square) through studying and identifying the levels of the reciprocal correlation of advertising signs impact on urban scene , then finding out the indicators and potential values which have made advertising signs as positive value by achieving the mechanisms of visual quality or a negative value by achieving mechanisms of visual pollution. And then examining the resulted visual perception defect reforming mechanism from it and identify the basic elements represented of the laws and legislation known worldwide. When presenting the problem, The research depends on: (Lack of clear perception
... Show MoreAnumerical solutions is presented to investigate the effect of inclination angle (θ) , perforation ratio (m) and wall temperature of the plate (Tw) on the heat transfer in natural convection from isothermal square flat plate up surface heated (with and without concentrated hole). The flat plate with dimensions of (128 mm) length × (64 mm) width has been used five with square models of the flat plate that gave a rectangular perforation of (m=0.03, 0.06, 0.13, 0.25, 0.5). The values of angle of inclination were (0o, 15o 30o 45o 60o) from horizontal position and the values of wall temperature (50oC, 60 oC, 70 oC, 90 oC, 100o<
... Show MoreModified asphalt is considered one of the alternatives to address the problems of deficiencies in traditional asphalt concrete, as modified asphalt addresses many of the issues that appear on the pavement layers in asphalt concrete, resulting from heavy traffic and vehicles loaded with loads that exceed the design loads and the large fluctuations in the daily and seasonal temperatures of asphalt concrete. The current study examined the role of polyphosphoric acid (PPA) as a modified material for virgin asphalt when it was added in different proportions (1%, 2%, 3%, 4%) of the asphalt weight. The experimental program includes the volumetric characteristics associated with the Marshall test, the physical properties, and th
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