The paper presents an investigation to the flutter speed of composite wing for different ply orientation. Structurally the composite wing was idealized as a composite beam load carrying structure. Theodorsen’s expression was used to get the 2- dimension unsteady lifting force and pitching moment in the limit of incompressible flow and subsonic speed which were integrated over the wing span. A free vibration analysis was first carried out to get the natural frequencies and mode shapes .The velocity-damping (V-g) method was used to calculate the flutter speed and the flutter frequency. A wing of unmanned aerial vehicle was manufactured from woven glass and polyester resin where the flutter speed was calculated experimentally by the wind
... Show MoreThis paper reports eight tests in which in-plane shear forces are applied across the joint between two different concretes forming a composite action. Shear can be transmitted across the joint either by interlocking of the aggregate particles protruding from each face or by shearing of the reinforcement crossing the joint. Tests are conducted on initially cracked specimens by depending only on dowel action. The results of the tests are compared with theoretical results of the exponential equation presented by Millard and Johnson. The computer program of Al-Shaarbaf using the nonlinear behavior of concrete
is used to perform the analysis with inclusion of the exponential equation for dowel action in the interface layer. The program use
Two dimensional turbulent natural convection heat transfer and fluid flow inside an air filled inclined square enclosure differentially heated has been numerically studied. Fully elliptic Navier- Stockes and energy equations are solved using finite volume method. The problem is simulated for different angles of inclination ( 0 180deg. ) and Rayleigh numbers ( 8 16 10 Ra 10 ). The turbulence k-є model is used to model the effect of turbulence. The wall function approach is used to model the regions near the walls of the enclosure. The obtained results from this study show that the rate of heat transfer is increased
with the increase of Rayleigh number and decreased with the increase of angle of inclination( 0
Experimental and theoretical studies have been carried out to study the adsorption of methane and carbon dioxide on 5A molecular sieve. Adsorption equilibrium isotherms of methane and carbon dioxide are reported for the temperature range 303– 333 K and pressure up to 2.5MPa. Experimental data were obtained using a static system for gas–solid adsorption. The Langmuir adsorption equilibrium equation gave
good predictions. Adsorption of methane and carbon dioxide on 5A molecular sieve is purely physical since the isosteric heat of adsorption was found to be equal to 14.804 and 37.218 kJ mole-1 for methane and carbon dioxide, respectively.
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
This study included the convective air drying of a single sweet potato sample which is taken as an ellipsoid with (40mm) in the longitudinal direction and (20mm) in the thickness direction. Convective heat and mass transfer takes place between the sample surface and its drying environment; while, unsteady heat conduction and moisture diffusion take place within the drying body without phase change for liquid (evaporation occurs at the surface only). The numerical solution of the mass, energy conservation equations was used; by applying the finite difference technique after using the body fitted coordinate system with grid generation techniques. A set of empirical correlations have been employed to determine the product properties and the
... Show MoreA program of laboratory testing is carried out to study the performance of laterally loaded piles
embedded in soil, which contains cavities. The testing apparatus is manufactured for carrying out the
tests and a simple technique was used to simulate the cavities.
The program of testing consists of five groups: Group One was carried out on pile embedded in soil
without cavities. The Second and Third Groups are performed on pile embedded in soil contains
single cavity located in front and in touch with pile face for the Second Group and in back and in
touch with pile face for the Third one. Group Four is performed on pile with the existence of two
cavities located in front and in touch with pile face. Group Five
The main title of the study is “THE GEOMETRICAL FORM IN MUSICAL HALL THROUGH THE CLASSICAL AND MODERN AGES” We live in a world full of sounds performed by human and different creatures which surround us from every direction, it’s not strange to know that acoustics has gone a long way through human experience because its related to many sides as mathematics and physics with accordance to architecture side, This side is related to the nature of space and its speech or music variation, each use has certain
determiners that affect the efficiency of acoustic performance. Musical halls have a main characteristic on the design and performing level through different periods. The architectural and acoustical literature's have dealt wi
Drilling fluid properties and formulation play a fundamental role in drilling operations. The Classical water-based muds prepared from only the Syrian clay and water without any additives((Organic and industrial polymers) are generally poor in performance. Moreover, The high quantity of Syrian clay (120 gr / l) used in preparing drilling fluids. It leads to a decrease in the drilling speed and thus an increase in the time required to complete the drilling of the well. As a result, the total cost of drilling the well increased, as a result of an increase in the concentration of the solid part in the drilling fluid. In this context, our study focuses on the investigation of the improvement in drilling mud Prepa
... Show MoreThe present work is an attempt to investigate the vibrations characteristics and effect of static stresses and deformation in partially pressurized thick cylindrical shells, such as the gun barrels. The method used cover analytical investigation developed to determine static stresses and deformation along the thick cylindrical shell using LAME'S equation. The numerical investigation is developed
using the finite element method with axisymmetric element (Plane 42) four nodes to determine the static response and solid element (Solid 45) eight nodes for vibration analysis by using the ANSYS package. The obtained results show a good agreement with the other investigators. It's found that the natural frequency of the selected models alm
The Indoor Environmental Quality (IEQ) describes an indoor space condition that the wellbeing and comfortability are provided for the users. Many researchers have highlighted the importance of adopting IEQ criteria, although they are not yet well defined in the Kurdistan region. However, environmental quality is not necessary for the contemporary buildings of the Kurdistan Region, and there is no measurement tool in the Region. This research aims to develop an IEQ assessment tool for the Kurdistan region using Mixed method methodology, both qualitative and quantitative. Therefore, a Delphi Technique was used as a method initially developed as systematic, interactive forecasting on a panel of experts. Thirty-five Delphi C
... Show MoreStud arc welding has become one of the most important unit operations in the mechanical industries. The need to reduce the time from product discovery to market introduction is inevitable. Reducing of standard deviation of tensile strength with desirable tensile strength joint as a performance character was use to illustrate the design procedure. The effects of (welding time, welding current, stud material, stud design, sheet material, sheet thickness, sheet cleaning and preheating) were studied. Design of Experiment (DOE) is a structured and organized method to determine relationships between factors affecting a process and output of the process itself. In order to design the best formulation it is of course poss
... Show MoreThis work presents a neural network based cost estimating method, developed for the generation
of conceptual cost estimates for total building and electromechanical systems in building project,
by using eight parameters available at the early design phase. This model establishes a
methodology that can provide an economical and rapid means of cost estimating. Eighteen ligh
rise building projects, built between 1996 and 2009 in Middle East countries used in this study.
The performance of developed cost models was tested against costs incurred by projects not used
in training of those models. Results show the mean absolute percentage errors (MAPE) are
between 1.51% and 4.771 % for the five networks, and the maximum/mini
شهد العالم المعاصر سلسلة من النزاعات والأزمات والحروب، فض ً لا عن صرامة الحياة، والتسارع التكنولوجي. فكان لابد من
استحضار الفكر الرومانسي لتنشيط الحياة من جديد. فالرومانسية تمثل العالم الداخلي للإنسان والحياة الوجدانية الخفية، والتي
ينبع منها طموح الإنسان في محاولته إرضاء مثله السامية.
جاء البحث مهتمًا بدراسة الفكر الرومانسي وتأثيره في العمارة. ولكون أكثر الدراسات والطروحات الأدبية تناولت مفهوم
ا
تناولت هذه الدراسة الخصائص الجيوتكنيكية لتربة محافظات بغداد وديالى وواسط وبابل واعتمدت على
الاستقراء والمقارنة والتحليل لخصائص التربة. حيث شملت هذه الدراسة جمع المعلومات وتبويبها وتحليلها
.(15 m) 7 …" ) ولحد عمق ,5 ,3 ,1 " m) ثم رسم خرائط جيوتكنيكية لكل خاصية ولأعماق
وشملت الخصائص المدروسة دراسة حدود القوام (حد السيولة ودليل اللدونة) ووزن وحدة الحجم الجاف نسبة
الفراغ الابتدائية ونسبة المواد الناعمة ومقاومة
The capacity of Tigris River to transport the sediment within Al Mosul City is one of the most important
characteristics of the river. Establishment of islands within this reach of the river because of decreasing the discharge of Tigris River can be controlled through studying this characteristic. Establishment of these
islands and increase of the sediment deposition in the river reach affect the water treatment plants and the urban and industrial activities that are located on the banks of this reach. A steady one dimensional mathematical model for simulating the flow and estimating the sediment transport capacity of the studied reach was implemented and run by using the HEC-RAS (Version 3.1.3) software and making use of recorded
Vibration monitoring is one of the most important techniques which are used to detect the cracks or defects in rotating mechanical systems. To distinguish characteristics of the system response that may lead to the transverse crack in rotating shaft, local asymmetry crack model is used where crack simulated by increasing the flexibility of the shaft and transverse crack in the shaft is introduced.
The obtained results showed a decreasing in the resonance shaft speed with increasing the crack depth ratio. The feature is used for diagnostics the crack in the shaft by using the graphed results between the natural frequency and shaft speed. The method of detecting was applied for several crack depth ratios (uncracked, %10, %20 and %30) in
In this research the specifications of Iraqi drinking bottled water brands are investigated throughout the comparison between local brands, Saudi Arabia and the World Health Organization (WHO) for bottled water standard specifications. These specifications were also compared to that of Iraqi Tap Water standards. To reveal variations in the specifications for Iraqi bottled water, and above mentioned standards some quality control tools are conducted for more than 33% of different bottled water brands (of different origins such as spring, purified,..etc) in Iraq by investigating the selected quality parameters registered on their marketing labels. Results employing Minitab software (ver. 16) to generate X bar,
... Show MoreThe purpose of this study is to evaluate the hydraulic performance and efficiency of using direction diverting blocks, DDBs, fixed on the surface on an Ogee spillway in reducing the acceleration and dissipating the energy of the incoming supercritical flow. Fifteen types of DDB models were made from wood with a triangulate shape and different sizes were used. Investigation tests on pressure distribution at the DDBs boundaries were curried out to insure there is no negative pressures is developed that cause cavitation. In these tests, thirty six test runs were accomplished by using six types of blocks with the same size but differ in apex angle. Results of these test showed no negative pressures developed at the boundarie
... Show MoreThis paper describes a comparison between beam-column junctions with and without construction joint, also, a parametric study deals with construction joint is presented by taking various conditions of the junction. These include the various positions of the construction joint, the axial load on the column, strength of concrete in the second cast and the amount of dowels crossing the joint. By developing a computer program which was originally written by Dr. Ihsan Al-Shaarbaf (1990), (P3DNFEA, program of three dimensional nonlinear finite element analysis), to consider the effect of construction joint depending on the fact that the shear force can be transmitted across the shear plane either by interlocking of the aggregate particles prot
... Show More The performance of asphalt concrete pavement has affected by many factors, the temperature is the most important environmental one which has a large effect on the structural behavior of flexible pavement materials. The main cause of premature failure of pavement is the rutting, Due to the viscoelastic nature of the asphalt cement, rutting is more pronounced in hot climate areas because the viscosity of the asphalt binder which is
inversely related to rutting is significantly reduced with the increase in temperature resulting in a more rut susceptible paving mixtures. The objective of this study is to determine the effect of temperatures variations on the permanent deformation parameters (perm
Nowadays, the use of recycled waste construction materials instead of aggregates is becoming popular in construction owing to its environmental benefits. This paper presents an experimental and analytical campaign to study the behavior of axially loaded columns constructed from recycled aggregates. The latter was used instead of natural aggregates, and they were collected from the waste of previous concrete constructions. Different concrete mixtures made from varying amounts of recycled aggregates ranged from 0 to 50% of the total coarse aggregate were conducted to achieve 28 MPa. The effect of steel fibers is another investigated variable with volumes ranged from 0 to 2% concerning concrete’s mixture. The experimental
... Show MoreAn analytical modeling of natural convection in physically-based analysis is developed for investigate free convective heat transfer in horizontal eccentric annulus between a circular outer cylinder and heated different shape inner envelope with used four models of the shapes of the inner cross section of (circular, triangular, square and hexagon inner boundary). The main objective of this paper was taking a composite model based on asymptotic solutions for three limiting cases: pure conduction, laminar boundary layer convection and transition flow convection. Laminar conditions up to Rayleigh number RaPi of 5×104 <
... Show MoreThe variation of compression index Cc and swelling index Cs with the degree of saturation S was studied on unsaturated and fully saturated soils for different degrees of saturation (100%, 91%, 85%, 75%, 60%), several mathematical equations were found to describe these relationships, these equations can be used to predict settlement during the consolidation process in unsaturated and fully saturated soils.
Population growth and urban development have posed challenges for wastewater treatment plants (WWTPs) locations in large cities such as Baghdad since they fail to meet sustainability criteria due to outdated planning and the lack of an approved strategy to determine the appropriate location for a WWTP in it. This study aims to develop a decision-making strategy for sustainable sites for WWTPs by using the Fuzzy Analytic Hierarchy Process (FAHP) and applying the strategy to evaluate the locations of the major WWTPs in Baghdad. Nine factors affecting decision-making regarding WWTP locations were categorized into three groups based on environmental, economic, and social sustainability requirements. A questionnaire method wa
... Show MoreAshShinnafiyah and AsSamawa cities suffer from significant increase in salinity of Euphrates River water compared with their counterpart's north AshShinnafiyah city which is reflected adversely on the quality of water within the study area. The study aims to find possible solutions to avoid the deterioration of Euphrates River northern AshShinnafiyah city until AsSamawa city that were
presented by total dissolved solid TDS. Twelve main hydrological and fifteen salinity measurement stations were selected to cover 117 km of the river reach within the study area during July-2011. Additional twenty three hydrological and salinity stations were adopted during March-2012, winter season to the river within the study area. After conducting t
Airborne radioactive particulates (for both indoor and outdoor air), in Al-Jaderiya region (Baghdad), have been collected to measure the concentration of Radon-222 daughter products of gamma ray emission (214Pb, 214Bi and 218Po) and hence calculate the concentration of Radon-222. 24 samples were analyzed (12 indoor and others outdoor), using gamma ray spectrometric system based on a High purity Germanium detector (HpGe) of (40%) efficiency. The average concentrations of Radon-222, were found to be (93.7 Bq/m
... Show MoreThe present work divided into two parts, first the experimental side which included the
measuring of the first natural frequency for the notched and unnotched cantilever composite beams
which consisted of four symmetrical layers and made of Kevlar- epoxy reinforced. A numerical
study covers the effect of notches on the natural frequencies of the same specimen used in the
experimental part. The mathematical model for the beam contains two open edges on the upper
surface. The effect of the location of cracks relative to the restricted end, depth of cracks, volume
fraction of fibers and orientation of the fiber on the natural frequencies are explored. The results
were calculated using the known engineering program (ANSY
An experimental study on a KIA pride (SAIPA 131) car model with scale of 1:14 in the wind tunnel was made beside the real car tests. Some of the modifications to passive flow control which are (vortex generator, spoiler and slice diffuser) were added to the car to reduce the drag force which its undesirable characteristic that increase fuel consumption and exhaust toxic gases. Two types of calculations were used to determine the drag force acting on the car body. Firstly, is by the integrating the values of pressure recorded along the pressure taps (for the wind tunnel and the real car testing), secondly, is by using one component balance device (wind tunnel testing) to measure the force. The results show that, the avera
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