Electrically heated horizontal cylinders of diameters 2.15cm,3cm, and 3.8cm were vibrated vertically in stagnant air at a frequency (10,15,20Hz) and amplitude range from (0.0005m) to (.0076m). The effect of different parameters on the heat transfer ratio (hv/ho) was investigated from its outer surface. It is concluded that, heat transfer ratio increases at high frequency and small diameter. Vibration Reynolds number has good effects on heat transfer ratio. (Gr.Pr) has bad indication on heat transfer ratio at high temperature difference (high heat flow). The vibration intensity also has good influence on heat transfer.
A theoretical study of a three-dimensional natural convection heat transfer from an isothermal horizontal square plate, with upper and lower heated surfaces is present. The transient Navier–Stokes and energy equations were solved by using finite deference method (F.D.M). The complete Navier–Stokes equations are transformed and expressed in terms of vorticity–vector potential and solved using an Alternating Direction Implicit (ADI) method for the parabolic portion of the problem, and Successive Over–Relaxation (SOR) method for the elliptic portion .A computer program in (FORTRAN 77) was built to carry out the solution. The numerical results were obtained for laminar flow range of Grashof number up to (105) in up ward–facing and
... Show MoreActive control strategy had been used for controlling the vibration response, with considering the
simplification in the design and keep away from complexity and high cost in order to extend the actual
application of the active control systems. The control program is responsible for identifying the acquired
data and make comparisons and decisions required for increase or decrease the actuator stiffness, by
instructing the control signal to open the inlet or the exhaust valve respectively. The PC sound card has
been used as a Data Acquisition Card. The proposed control strategy had been simulated and tested to
control the vibration response of a single degree of freedom spring-mass-damper system excited
harmonically a
In the 1980s, the French Administration Roads LCPC developed high modulus mixtures (EME) by using hard binder. This type of mixture presented good resistance to moisture damage and improved . mechanical properties for asphalt mixtures including high modulus, good fatigue behaviour and excellent resistance to rutting. In Iraq, this type of mixture has not been used yet. The main objective of this research is to evaluate the performance of high modulus mixtures and comparing them with the conventional mixture, to achieve this objective, asphalt concrete mixes were prepared and then tested to evaluate their engineering properties which include moisture damage, resilient modulus, permanent deformation and fatigue characteristics. These prope
... Show MoreAs a result of the growth of economic, demographic and building activities in Iraq, that necessitates carrying out geotechnical investigations for the dune sand to study behavior of footings resting on these soils. To determine these properties and to assess the suitability of these materials for resting shallow foundation on it, an extensive laboratory testing program was carried out. Chemical tests were carried out to evaluate any possible effects of the mineralogical composition of the soil on behavior of foundation rested on dune sands.
Collapse tests were also conducted to trace any collapse potential. Loading tests were carried out for optimum water content and different shapes of footing. Loading test recommends manufacturing o
Buried pipeline systems are commonly used to transport water, sewage, natural oil/gas and other materials. The beneficial of using geogrid reinforcement is to increase the bearing capacity of the soil and decrease the load transfer to the underground structures.
This paper deals with simulation of the buried pipe problem numerically by finite elements method using the newest version of PLAXIS-3D software. Rajkumar and Ilamaruthi's study, 2008 has been selected to be reanalyzed as 3D problem because it is containing all the properties needed by the program such as the modulus of elasticity, Poisson's ratio, angle of internal friction. It was found that the results
... Show MoreA description is given of the resistance spot welding process in terms of internal behavior of the weld as welding takes place. Heat input due to spot welding of steel sheet plate causes temperature gradient in the parent metal. After cooling, residual stresses appear around the welding zone reducing the strength. Residual stresses are a result of the temperature gradient and the dependency
of material properties on the temperature, such as yield strength, elasticity modulus, and thermal expansion coefficient. Nonlinear transient heat transfer analysis performed in order to obtain the temperature distribution in the welded part .A nonlinear thermo–plastic stress analysis is then performed to predict the stress and strain fields dur
This 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
A Mobile Ad hoc Network (MANET) is a collection of mobile nodes, that forms on the fly a temporary wireless multi-hop network in a self-organizing way, without relying on any established infrastructure. In MANET, a pair of nodes exchange messages either over a direct wireless link, or over a sequence of wireless links including one or more intermediate nodes. For this purpose, an efficient routing protocol is required. This paper introduced performance study of three of MANET protocols (AODV, GRP and OSPFv3). This study was one of the newer studies because wireless communication played an important role in today’s application and the field of mobile ad hoc network becomes very popular for the researchers in the last years. This study w
... Show MorePresented in this paper is a series of bending moment influence surfaces for concrete rectangular plates simply supported at three edges and built-in at the fourth edge. The solutions are obtained analytically on the basis of thin plate's theory with small deflection using double Fourier series. The influence surfaces are presented for two observation points namely the center of the plate as well as the midpoint of the built-in edge. A computer program was written in FORTRAN language to generate the influence surfaces making use of the developed analytical solutions of this work. The validity of the computer solution was confirmed by comparing its results with published results for zero Poisson's ratio and excellent agreement was obtaine
... Show MoreMicrobial fuel cell is a device that uses the microorganism metabolism for the production of electricity under specific operating conditions. Double chamber microbial fuel cell was tested for the use of two cheap electrode materials copper and aluminum for the production of electricity under different operating conditions. The investigated conditions were concentration of microorganism (yeast) (0.5- 2 g/l), solutions temperature (33-45 oC) and concentration of glucose as a substrate (1.5- 6 g/l). The results demonstrated that copper electrode exhibit good performance while the performance of aluminum is poor. The electricity is generated with and without the addition of substrate. Addition of glucose substrate
... Show MoreA fuzzy recognition model for some handwritten Arabic alphabet is designed. This fuzzy model could be envisaged as an algorithm which is structured over two concepts. First; the handwritten character variation is modeled by the fuzziness of the feature vector's elements. Second; the notion of entropy is fuzzily modified to extract the amount of information in the elements within the feature vector so as to speed up the recognition process. Consequently, a fuzzy recognition graph of the optimum paths decision tree is designed for the handwritten Arabic alphabet character's recognition.
Root-finding is an oldest classical problem, which is still an important research topic, due to its impact on computational algebra and geometry. In communications systems, when the impulse response of the channel is minimum phase the state of equalization algorithm is reduced and the spectral efficiency will improved. To make the channel impulse response minimum phase the prefilter which is called minimum phase filter is used, the adaptation of the minimum phase filter need root finding algorithm. In this paper, the VHDL implementation of the root finding algorithm introduced by Clark and Hau is introduced.
VHDL program is used in the work, to find the roots of two channels and make them minimum phase, the obtained output results are
The main source of water supply in Iraq is the surface water, especially Tigris and Euphrates Rivers and their tributaries. In the recent years there was a great drop in the water levels of Tigris River within Baghdad City which had affected the operation of twelve water supply projects located on the banks of Tigris River in Baghdad City, due to significant climate changes, and the expansion of hydraulic construction (dams) and implementation of new irrigation projects in Turkey, these factors have greatly reduced the water flowrates of river by about 46%. In the present study the flow characteristics of Tigris River within Baghdad City was studied, the reach involved was about 49km in which it represents the urban zone
... Show MoreIn this research the performance of 5G mobile system is evaluated through the Ergodic capacity metric. Today, in any wireless communication system, many parameters have a significant role on system performance. Three main parameters are of concern here; the source power, number of antennas, and transmitter-receiver distance. User equipment’s (UEs) with equal and non-equal powers are used to evaluate the system performance in addition to using different antenna techniques to demonstrate the differences between SISO, MIMO, and massive MIMO. Using two mobile stations (MS) with different distances from the base station (BS), resulted in showing how using massive MIMO system will improve the performance than the standar
... Show MorePhase change materials are known to be good in use in latent heat thermal energy storage (LHTES) systems, but one of their drawbacks is the slow melting and solidification processes. So that, in this work, enhancing heat transfer of phase change material is studied experimentally for in charging and discharging processes by the addition of high thermal conductive material such as copper in the form of brushes, which were added in both PCM and air sides. The additions of brushes have been carried out with different void fractions (97%, 94% and 90%) and the effect of four different air velocities was tested. The results indicate that the minimum brush void fraction gave the maximum heat transfer in PCM and reduced the time
... Show MoreIn the present work a theoretical analysis depending on the new higher order . element in shear deformation theory for simply supported cross-ply laminated plate is developed. The new displacement field of the middle surface expanded as a combination of exponential and trigonometric function of thickness coordinate with the transverse displacement taken to be constant through the thickness. The governing equations are derived using Hamilton’s principle and solved using Navier solution method to obtain the deflection and stresses under uniform sinusoidal load. The effect of many design parameters such as number of laminates, aspect ratio and thickness ratio on static behavior of the laminated composite plate has been studied. The
... Show MoreThis research investigates manganese (Mn) extraction from Electric Arc Furnace Steel Slag (EAFS) by using the Liquid-liquid extraction (LLE) method. The chemical analysis was done on the slag using X-ray fluorescence, X-ray diffraction, and atomic absorption spectroscopy. This work consisted of two parts: the first was an extensive study of the effect of variables that can affect the leaching process rate for Mn element from slag (reaction time, nitric acid concentration, solid to liquid ratio, and stirring speed), and the second part evaluates the extraction of Mn element from leached solution. The results showed the possibility of leaching 83.5 % of Mn element from the slag at a temperature of 25°C, nitric acid co
... Show MoreThe present work describes numerical and experimental investigation of the heat transfer characteristics in a plate-fin, having built-in piezoelectric actuator mounted on the base plate (substrate). The geometrical configuration considered in the present work is representative of a single element of the plate-fin and triple fins. Air is taken as the working fluid. A performance data for a single rectangular fin and triple fins are provided for different frequency levels (5, 30 and
50HZ) , different input power (5,10,20,30,40 and 50W) and different inlet velocity (0.5, 1, 2, 3, 4, 5 and 6m/s) for the single rectangular fin and triple fins with and without oscillation. The investigation was also performed with different geometrical fin
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 MoreRecently, the development and application of the hydrological models based on Geographical Information System (GIS) has increased around the world. One of the most important applications of GIS is mapping the Curve Number (CN) of a catchment. In this research, three softwares, such as an ArcView GIS 9.3 with ArcInfo, Arc Hydro Tool and Geospatial Hydrologic Modeling Extension (Hec-GeoHMS) model for ArcView GIS 9.3, were used to calculate CN of (19210 ha) Salt Creek watershed (SC) which is located in Osage County, Oklahoma, USA. Multi layers were combined and examined using the Environmental Systems Research Institute (ESRI) ArcMap 2009. These layers are soil layer (Soil Survey Geographic SSURGO), 30 m x 30 m resolution of Digital Elevati
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In this work, an experimental investigation has been done for heat transfer by natural-convection through a horizontal concentric annulus with porous media effects. The porous structure in gap spacing consists of a glass balls and replaced by plastic (PVC) balls with different sizes. The outer surface of outer tube is isothermally cooled while the outer surface of inner tube is heated with constant heat flux condition. The inner tube is heated with different supplied electrical power levels. Four different radius ratios of annulus are used. The effects of porous media material, particles size and annulus radius ratio on heat dissipation in terms of average Nusselt number have been analyzed. |
One-third of the total waste generated in the world is construction and demolition waste. Reducing the life cycle of building materials includes increasing their recycling and reuse by using recycled aggregates. By preventing, the need to open new aggregate quarries and reducing the amount of construction waste dumped into landfills, the use of recycled concrete aggregate in drum compacted concrete protects the environment. Four samples of PRCC were prepared for testing (compressive strength, tensile strength, flexural strength, density, water absorption, porosity) as the reference mix and (10, 15, and 20%) of fine recycled concrete aggregate as a partial replacement for fine natural aggregate by volume. The mix is designed according to
... 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
A new approach for baud time (or baud rate) estimation of a random binary signal is presented. This approach utilizes the spectrum of the signal after nonlinear processing in a way that the estimation error can be reduced by simply increasing the number of the processed samples instead of increasing the sampling rate. The spectrum of the new signal is shown to give an accurate estimate about the baud time when there is no apriory information or any restricting preassumptions. The performance of the estimator for random binary square waves perturbed by white Gaussian noise and ISI is evaluated and compared with that of the conventional estimator of the zero crossing detector.
Date stones were used as precursor for the preparation of activated carbons by chemical
activation with ferric chloride and zinc chloride. The effects of operating conditions represented
by the activation time, activation temperature, and impregnation ratio on the yield and adsorption
capacity towards methylene blue (MB) of prepared activated carbon by ferric chloride activation
(FAC) and zinc chloride activation (ZAC) were studied. For FAC, an optimum conditions of 1.25
h activation time, 700 °C activation temperature, and 1.5 impregnation ratio gave 185.15 mg/g
MB uptake and 47.08 % yield, while for ZAC, 240.77 mg/g MB uptake and 40.46 % yield were
obtained at the optimum conditions of 1.25 h activation time, 500
The artistic dimension appears as an important factor in urban townscape's identity shaping, as many cities in the world have a different identity through the different artistic elements in it, the artistic dimension is meant within the research (set of artistic elements that can contribute to urban identity shaping, whether on architecture or on urban design in addition to public, urban arts). Many previous global studies have dealt with one type or more of art affecting the urban townscape identity of specific cities as a case study. Thus, we can diagnose the research problem as (the lack of local knowledge about the role of the artistic dimension in all its components in achieving the urban townscape identity), and th
... Show MoreThis research deals with the review of former research that made to solve the challenges and complexities of both static and dynamic soil structure interaction through discussing advanced computational models and their applications and exploring methods of solving the challenges of soil structure interaction in foundation engineering to provide a guide for the engineering community through the complexes of soil structure interaction. It was found that the numerical analysis for both static and dynamic soil structure interaction using the finite element method with the aid of advanced computional models is ideal for dealing with the non-linearity of soil and structure properties and loading conditions and that the use of
... Show MoreThe seismic design of pile foundations mainly relies on analyzing the seismic response of layered, liquefiable locations. Two design scenarios are taken into consideration from the case histories; the first is how pile foundations react to the stresses and lateral displacements brought on by the lateral dispersion of liquefied soil. The second is how to piles reaction to seismic activity that occurs with the development of high pore water pressures. The PLAXIS 3D software is utilized in this research with a non-linear soil constitutive model (hypoplastic model) for both dry and saturated loose sandy soils under the impact of two earthquakes and the motion of different features to give a complete understanding of the dyna
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