The aerodynamic characteristics of forward swept wing were studied theoretically and experimentally .In the present work, theoretically a computer program was constructed to predict the pressure distribution about surface of the wing using three dimensional Low Order Subsonic Panel method. The aerodynamic coefficients of the wing were calculated from the pressure distribution which gained from tangential velocities Experimentally ,test were carried out by designing and manufacturing a wing model with special arrangement for pressure tapping, suitable for low wind tunnel testing. The entire wing was rotated rotate about an axis in the plane of symmetry and normal to the chord to produce different sweep and incidence angles for wing, by using rotating mechanism. Wind tunnel test was carried out at (Uپ‡=33.23m/s) for different swept angles and angles of attack.Comparisons were made between the predicted and experimental results. It is good and gave reasonable closeness. It was clear from the present investigation that the lift and drag characteristics for the forward swept wing are less in values compared with the swept back wing, therefore a forward swept wing can fly at higher speed corresponding to a pressure distribution associated for lower speed.
The aim of this paper is to in investigate the performance characteristics of counter flow wet cooling towers experimentally by varying air and water temperatures, fins angle, rate of air flow, rate of water flow as well as the evaporation heat transfer, along the height of the tower. The analysis of the theoretical results revealed before that the thermal performance of the cooling tower is sensitive to the degree of saturation of inlet air. Hence, the cooling capacity of the cooling tower increases with decreasing inlet air temperature whereas the overall water temperature fall is curtailed with increasing water to air mass ratio. From the experimental study the efficiency of the cooling tower and cooling tower characteristics are higher in case of low mass flow ratio due to higher contact area of water to air. Because of better contact area between airs to water the drop in performance of the cooling tower is less. The effect of fins angle on the thermal performance of counter flow wet cooling tower was predicted. The experimental study showed that the cooling range, cooling coefficient, , heat load , change in air relative humidity and cooling tower effectiveness increased with increasing fins angles and optimum fins angle obtained from this experimental work was 70 degree, at this angle all cooling tower performance has been calculated were better. While the approach increased with decreasing fins angles, the minimum approach was obtained for 70 degree fins angles and the maximum approach was obtained for 30 degree fins angles.
The white cement Kiln dust (WCKD) is a secondary production from the cement industry through its production operation. Environmentally, it is considered as an unwanted waste because it causes air pollution and ground congealment, and it is needed great efforts and financial support to disposal it. In this study, the WCKD was used partially instead of limestone as a filler in the asphalt mix, where it was used by ratios of 0%,25%,50%,75% and 100% from the weight of limestone. An evaluation of the mechanical characteristics was conducted by carrying out Marshall test and Indirect Tensile test, and the results showed that the increase in the WCKD percent reduces the asphalt mix density and increases the percentage of air voids, while the other characteristics (stability, Marshall Stiffness, flow and Indirect Tensile Strength) increase when the WCKD ratio is 25% and 50%. These those characteristics start decreasing when the WCKD ratio was 75% and 100%. The study showed that the optimum ratio of the WCKD is 50% from the limestone weight, and the WCKD cannot be used as a filler entirely in asphalt mix, but it can be used partially.
The research evaluated the wastewater effluents , Two pump stations discharged directly without any treatment in AL-WARAR Canal in Ramadi City ,located in the southern bank of the Canal . These effluents collects the storm water from the residential area , the drainage open channel which bypassing by septic tanks of domestic wastewater , bypassing from septic tanks of domestic wastewater. Laboratory Tests out on (December 2010 to May 2011) for the Canal (upstream) , wastewater effluents, and Canal ( downstream) to determine the quality characteristics and the wastewater effects upon the AL-WARAR Canal . The results show an increase in almost concentrations of characteristics compared to the Iraqi Standards NO. (25 –B1) in (1967) of the conservation of water resources , where the Bio-chemical oxygen demand , chemical oxygen demand and Total Bacterial Count were increased by (11, 9.7 and 535) times respectively. According to the organic load , the wastewater effluents classified as low strength . This study shows that the value of the reaction constant rate (k1) and Reaeration constant rate (k2)were about (0.187/day) and (0.556 /day ) respectively . Two stations downstream were located to determine the wastewater effects upon the Canal , Dissolved Oxygen was measured and calculated by using (STREETER –PHELPS) equations , then Sag curve of AL-WARAR Canal was determined .In spite of that the wastewater effluent does not comply with the Iraqi Standards discharged into water resources NO. (25 –B1) in (1967) , AL-WARAR Canal still comply with the Iraqi standards (NO. 25-A1) in (1967) of the conservation of water resources by the effect of self-purifications.
The present work represents a two-dimensional numerical investigation of forced laminar flow heat transfer over a 3-rows oval-tube bank in staggered arrangement with rectangular longitudinal vortex generators (LVGs) placed behind each tube. The effects of Reynolds number (from 250 to 1500), the positions (3 in x-axis and 2 in y-axis) and angles of attack (30o and 45o) of rectangular VGs are examined. The study focuses on the Influence of the different parameters of VGs on heat transfer and fluid flow characteristics of three rows oval-tube banks. The characteristics of average Nu number and skin friction coefficient are studied numerically by the aid of the computational fluid dynamics (CFD) commercial code of FLUENT 6.3. The results showed increasing in the heat transfer and skin friction coefficient with the increasing of Re number and decreasing the relative distance of positions of LVGs. It has been observed that the overall Nuav number of three oval-tubes increases by 10–20.4% and by 10.4–27.7% with angles of 30o and 45o respectively, with increasing in the overall average of skin friction coefficient of three oval-tubes reached to 53% and 72% with two angles used respectively, in comparison with the case without VGs.
The construction of pavement layers on subgrade soil with good characteristics decreases the thickness of these layers, which in turn lowers the cost of building and maintaining roadways. However, it is impossible to avoid constructing pavements on unsuitable subgrade due to a number of limitations. Using conventional additives like lime and cement to improve subgrade properties results in additional costs. As a result, utilizing by-products (cement kiln dust and reclaimed asphalt pavement) in this field has benefits for the environment, economy, and technology. Large amounts of cement kiln dust (CKD), a by-product material, are produced in Portland cement factories. On the other hand, large amounts of reclaimed asphalt pavement (RAP) are accumulated as a result of the rehabilitation of old roads. This paper discusses using CKD and RAP to improve the characteristics of poor subgrade layers by conducting a series of Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests on samples of natural soil and soil stabilized with different percentages of CKD and RAP with different curing times to investigate their impacts on soil properties. The curing was carried out by wrapping the stabilized samples with several layers of nylon and then placing them in plastic bags at room temperature. The compaction results illustrated that the addition of CKD increases OMC and decreases MDD, in contrast to RAP, which decreases OMC and increases MDD. The addition of CKD and RAP led to a significant and unexpected increase in the CBR values. The results show that the soaked and unsoaked CBR values improve from 3.4% and 12.1% for natural soil to 220.1% and 211%, respectively, after adding 20% CKD and curing the samples for 28 days. Also, the addition of 25% RAP to soil-20% CKD blend increased the soaked and unsoaked CBR values to 251% and 215%, respectively. All the additions resulted in a significant reduction in swelling.
RSM and DOEs approach were used to optimize parameters for hypoeutectic A356 Alloy. Statistical analysis of variance (ANOVA) was adopted to identify the effects of process parameters on the performance characteristics in the inclined plate casting process of semisolid A356 alloy which are developed using the Response surface methodology (RSM) to explain the influences of two processing parameters (tilting angle and cooling length) on the performance characteristics of the Mean Particle Size (MPS) of α-Al solid phase and to obtain optimal level of the process parameters. The residuals for the particle size were found to be of significant effect on the response and the predicted regression model has extracted all available information from the experimental data. By applying regression analysis, a mathematical predictive model of the particle size was developed as a function of the inclined plate casting process parameters. In this study, the DOEs results indicated that the optimum setting was approx. (44) degree tilt angle and (42) cm cooling length with particle size (30.5) μm
The research studies the prediction of thermal characteristics for open designer shape of solar collector of flat plate of area 2.34m2, connected to water tank of 85 liter capacity . Mathematical model was represented and made the system of private accounts, transactions and through the creation of mathematical equations and solved numerically using the method of Finite Difference Method (FDM).The results of research is to obtain hot water at average temperatures up to 520C at mid-day during February month, as the water temperature is at its lowest value in this month in Baghdad city, with an average efficiency of the system up to 53.6% .This predictive study is compared with a previous measurement work and confirmed that the results match well.
This research represents part of the current attempts to employ remote sensing data in the scopes of the civil engineering and the geotechnical engineering applications. There is great need to know the kinds of soil and their geotechnical properties, to create recent maps which have the capability and high flexibility to deal with them in digitizing way. Therefore GIS techniques are employed in the soil of area of study . By using ArcView software, a geographical database and information about soil chemical properties analysis have been registered and constructed digitally to represent the geotechnical soil characteristics maps . The work includes the digital image processing ( digital classification techniques) by using ERDAS, ver.,8.4 package, and classify the soil of study area by using the supervise and unsupervised techniques . The geotechnical maps by using GIS techniques depend on remote sensing data are the better to represent the ground truth regarding the characteristics of soil , in comparison with the traditional method, because they are easy way to produce, use, store and update, in addition they save in efforts, time and cost . The results of this study have shown that the soil of study area is gypsum where it ratio exceeded the allowable ratio ( 10.75 % ) for all samples . In addition the total Soluble Salts ratio and SO4 ratio high compared to allowable ratio (10 % , 5 %) respectively .
Designing large structures like dams requires carefully selecting various geometric, hydraulic, and structural characteristics. The required structural design and performance criteria are considered when selecting these characteristics. In order to find the best solution, a variety of restrictions must simultaneously be carefully taken into account. This study presents an effective method for determining the optimal shape design for concrete buttress dams. The research was divided into two crucial phases. The dam's initial design and subsequent modeling were mostly done using DIANA FEA and traditional design and stability analysis. After that, a genetic algorithm was used on the MATLAB platform to control optimizing the dam's shape. Three design factors were used in this phase to alter the goal function and to reduce the amount of Concrete used, which decreased project costs. These variables covered three areas of the buttress's cross-section. Two important limitations were scrutinized during this optimization process: establishing a safety margin against overtopping and preventing sliding. The analysis included a detailed assessment of Shear friction stability to complete a thorough stability study. The optimization efforts had a spectacular result, resulting in a significant 52.365% reduction in the total volume of Concrete used, dropping from 19147.5 cubic meters to 9122.55 cubic meters. This decrease was made possible by reducing three distinct components (X1, X2, X3), with respective proportions of 37.5%, 13.33%, and 30%, including two segments related to the buttress and the final segment linked (slab) to the strip footing.
A gradual change in the state and properties of the oil transformer due to aging, which generally leads to break down. Aging of the mineral oil cause permanent harmful change of the ability insulation system. Aging of the mineral oil and water content of paper insulation are simulated at the laboratory by putting the samples of the oil and pieces of insulation paper in a rig (transformer manufactured) and exposed to different temperatures (20Co, 40Co, 60Co, 80Co) for specific durations of time to analysis and improve the performance of the transformer. In this research, the electrical and physical characteristics for the mineral oil and paper insulation have been studied and then repeated by the addition of different concentration of Nanoparticales (ZnO) (0.01, 0.03, 0.05, 0.07)gm/ml then compared with the electrical properties of the pure mineral oil and paper insulation without (ZnO) nanoparticales
Traffic accidents and traffic delay have a negative impact on the mobility traffic flow due to their huge costs on the transport system. Thus one of the main primary aims for transport policy makers are reducing the negative effect of traffic accidents and traffic delay on the road network. In this study, fixed and random parameters Tobit models have been developed to model the accident rates from 20 intersections in Al-Karakh district in Baghdad City, Iraq. The safety significant of logarithm of annual average daily traffic, the percentage of heavy vehicles and the delay time for both major and minordirections for each intersection on the accident rates were evaluated. The main finding of this study shows that delay has an important effect on traffic accident rates of intersections. Regarding to the effect of other factors on traffic Accident rates, the result of the model shows that the logarithm of annual average daily flow, the percentage of heavy vehicles for both major and minor directions of the intersection are positively associated with more accident rates.
A solar water heating system has been fabricated and tested to analyze the thermal performance of Parabolic Trough Solar Collector (PTSC) using twisted tape insert inside absorber tube with twisted ratio about TR=y/w=1.33. The performance of PTSC system was evaluated by using three main important indicators: water outlet temperature (Tout), useful energy and thermal efficiency (ηth) under the effect of mass flow rate (ṁ) ranges between 0.02 and 0.04 Kg/s with the corresponding of Reynolds number (Re) range (2000 to 4000). In a parallel, a fuzzy-logic model was proposed to predict the thermal efficiency (ηth) and Nusselt number (Nu) of PTSC depending on the experimental results. The fuzzy model consists of five input and two output parameters. The input parameters include: solar intensity (I), receiver temperature (Tr), water inlet temperature (Tin), water outlet temperature (Tout) and water mass flow ( ) while, the output include the thermal efficiency (ηth) and Nu. The final results indicate that, owing to the mixture of the swirling flow of the perforated twisted-tape insert, the perforated twist tape insert enhances the heat transfer characteristics and the thermal efficiency of the PTSC system. More specifically, the use of perforate twist tape inserts enhanced the thermal efficiency by 4% to 4.5% higher than smooth absorber tube. Also, the predicted values were found to be in close agreement with the experimental counterparts with accuracy of ~92 %. So, the suggested Fuzzy model system would have high validity and precision in forecasting the success of a PTSC system compared to that of the traditional model. Pace, versatility, and the use of expert knowledge for estimation relative to those of the traditional model are the advantages of this approach
Scientists have recently started looking for new ecologically friendly and sustainable materials. Construction materials are among the numerous widely employed materials, and it is normally acknowledged that they have an apparent detrimental influence on the environment. Thus, the contribution of this paper is to describe the palm frond natural fibers' effect on concrete's mechanical characteristics. Since concrete is a brittle material, the goal of this research is to increase the tensile strength of concrete by using organic fibers (palm frond fibers), a waste product. In order to determine the ideal percentage of fibers, the following percentages were tested: 0.25, 0.5, 0.75, and 1% by volume of concrete. On dry density, compressive strength, and tensile strength, the impacts of fibers were investigated. The density of concrete decreased with increasing fiber ratios. The compressive strength slightly decreased, while the splitting strength significantly improved. According to the results, the best amount of palm frond fibers that can be add to concrete is 0.75% by volume.
In this study, thermal-hydraulic performance of a confined slot jet impingement with Al2O3-water nanofluid has been numerically investigated over Reynolds number ranges of 100-1000. Two triangular ribs are mounted at a heated target wall; one rib located on the right side of the stagnation point and another one located on left side of the stagnation point. The governing momentum, continuity and energy equations in the body-fitted coordinates terms are solved using the finite volume method and determined iteratively based on SIMPLE algorithm. In this study, effects of Reynolds number, rib height and rib location on the thermal and flow characteristics have been displayed and discussed. Numerical results show an increase in the average Nusselt number and pressure drop when Reynolds number and rib height increases. In addition, the pressure drop and average Nusselt number increases with decrease the space between the stagnation point and rib. The maximum enhancement of the average Nusselt number is up to 39 % at Reynolds number of 1000, the rib height of 0.3, rib location of 2 and nanoparticles volume fraction of 4%. The best thermal-hydraulic performance of the impinging jet can be obtained when the rib height of 0.2 and rib location of 2 from the stagnation point with 4% nanoparticles volume fraction.
This study assessed the temporal and spatial water quality variability to reveal the characteristics of the Shatt Al-Arab River, Basrah, Iraq. A total of 14 water quality parameters (water temperature (T), pH, electrical conductivity (EC), Alkanets (Alk), total dissolved solids (TDS), turbidity (Tur), total hardness (TH), calcium (Ca), magnesium (Mg), chloride (Cl), sulphate (SO4), total suspended solids (TSS), sodium (Na), and potassium (k)) were analyzed Use of multivariate statistical methods in a total of three stations for the period 2016-2017. In this study was use a statistical approach to determine the water quality using the Pearson Correlation Index (PCI), Principal component analysis (PCA), and Factor Analysis (FA) were used to analyze the data. Main water pollutant sources were wastewater from agricultural drainage and industrial wastewater. Significant relationships recorded between the investigated parameters based on the results of PCI, at the 0.01 and 0.05 significance levels. Per the FA results, 77.1 % of the total variance explained by two factors.
Determinations of unsaturated soil parameters using experimental procedures are time consuming and difficult. In recent years, the soil–water characteristic curve (SWCC) has become an important tool in the interpretation of the engineering behavior of unsaturated soils. Difficulties associated with determining such parameters have justified the use of indirect determination. This paper presents the general nature of the SWCC for soils with different plasticity limits, index and gradation, in terms of gravimetric water content and degree of saturation versus soil matric suction from Anbar governorate. In order to investigate possible relationships between the plasticity limits, index, percent passing no.200 and SWCC, 7 type of soils were tested to find its SWCC experimentally and compared the result with the curves obtained from different model presented in the literature. The objectives of the paper were to check the validity of these models with the experimental results. The results shows a good agreement and to present a simple method for inferring the SWCC for soils, taking into account the liquid limit, plastic limit, plasticity index and percent of fines passing sieve no.200.
The focusing in this study was on the contaminated-uncontaminated soils' properties whichstudied by performing experimental tests included, Atterberg’s limit, specific gravity, compaction,unconfined compression, and direct shear tests. Different % of crude oil was used in thecontaminated soils which are performed by mixing the soils using different percent of were oilof 3 %, 6 % and 9 % by dry weight. The main effect of oil contamination causes a reduction in theliquid and plastic limit values for clayey soil. Besides oil contamination gives a reduction in themaximum dry unit weight as well as a decreasing the optimum water content with comparisonto original soil (clayey and sandy soil). The angle of internal friction is decreased for sand whileit increases for clay is one of oil contamination results.
The Organo modified and unmodified sodium montmorillonite clay effect on thermal and mechanical properties of the waste low density polyethylene (wLDPE) were studied. Commercialize unmodified (MMT) and Organo-modified clay (OMMT) were added to the wLDPE to prepare wLDPE-clay noncomposites by melt intercalation method. OMMT and MMT were added in a range of 1-5 wt %. Fourier transform infrared spectroscopy (FTIR) used to evaluate polymer structure before and after the fabrication. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to analyse the thermal stability and thermal properties for the wLDPE and fabricated nanocomposites. Tensile mechanical characteristics of the waste specimens before and after nanocompsite fabrication were evaluated. The FTIR exhibited no change in the chemical structure of the wLDPE used after clay addition. Melting temperature and crystallization percentage were increased up to 1 wt% loaded and decreased in with clay content increasing when compared to the original waste matrix. The thermal steadiness of the wLDPE /clay nanocomposites were found enhanced in the case of loading 3 wt% of OMMT. The elastic modulus has improved in the 3% OMMT loaded.
In this paper, a proposed model based on phase matrix rotation was suggested to improve the performance of Multicarrier-Code Division Multiple Access (MC-CDMA) lies in Fast Fourier Transform (FFT) algorithm under the Additive White Gaussian Noise (AWGN) and frequency selective fading channel. This model is used to reduce the effect of multipath fading. The results extracted by a computer simulation for a single user, then it compared with the original technique for MC-CDMA based on FFT for both systems. As a result, it can be seen from the proposed technique that a high performance improvement was obtained over the conventional MC-CDMA, where the Bit Error Rate (BER) is widely reduced under different channel characteristics for frequency selective fading and the AWGN channel
The concrete members several blessings over steel beam, like high resistance to prominent tem-perature, higher resistance to fatigue and buckling, high resistance to thermal shock, fire re-sistance, robust resistance against, and explosion. However there are some disadvantages as a result of exploitation totally different materials to product it. The most downside of structural concrete member is its deprived the strength to tensile stresses.The bond mechanism between steel bars and concrete is thought to be influenced by multiple parameters, like the strength of the encompassing media, the prevalence of cacophonous cracks within the concrete and therefore the yield stress of the reinforcement. However, properties of concrete mass has significantly effect when it was subjected to elevated temperature.The objective of this paper presents the results that allocating with the bond behavior of the rein-forcement of steel bar systems below static pull-out loading tests subjected to elevated tempera-tures. This numerical technique relies on relative slip and therefore the stress of bond distribu-tions done the embedded length and size of the bar within the concrete cylinder specimens. The obtained results square measure given and commented with the elemental characteristics of ferroconcrete members. The comparison showed smart agreement with experimental results
The research deals with a study carried out on the influence of iron oxide (Fe2O3) on the characteristics of kaolin clay and the possibility of reducing iron oxide percentage in kaolin clay in the location of Ghamij in Anbar Governorate, prior to using it in industry. The raw material used in the research contained about 5.72% of iron oxide. When such a percentage of iron oxide is contained in kaolin clay, it makes it harmful in numerous industries such as paper, plastic, drugs etc….. In this research the hydro metallurgy method was used where oxalic acid was diluted with distilled water, and with the help of heat and mixing ( as assisting factor) to cause iron oxide to melt and thereafter subjected to filtration and thus the ‘Bakkag’, i.e. white kaolin which was almost free from iron oxide was obtained. The sample of kaolin raw material weighted about 25 grammas and the acid diluted in the distilled water used along periods of (2, 3) hours weighted (4,5,6,7,8,10) grammas. The findings showed that this method is very practical in ridding the kaolin samples from iron oxide; in the sample where the concentration of the acid amounted to 6 along a 3- hour period, the percentage of iron oxid reduced to 3.2% In this way much of iron oxide melted and even its red color of the raw material changed to white. The same result was obtained by using a No. 10 concentration acid was used for two hours, the percentage of iron oxid reduced to 3.18%.The construction of iron oxide reach to 45%,the loss in weight of raw material used in this research is about 14%.
Satellites may provide data with various spectral and spatial resolutions. The spatial resolution of panchromatic (PAN) images is higher, but the spectral resolution of multispectral (MS) images is greater. There is Satellite sensors limitation for capturing an image with high spatial and spectral resolution, due to the hardware design of the sensors. Whereas many remote sensing, as well as GIS applications, need high spatial and spectral resolution. Image fusion merges images of different spectral and spatial resolutions based on a certain algorithm. It can be used to overcome the sensor's limitation and play an important role in the extraction of information. The standard image fusion approaches lose spatial information or distort spectral characteristics. Optimizations of fusion rules can overcome and degrade the distortions as the fusion core is the image fusion rules. In this paper, the Grey Wolf Optimizer (GWO) is used to find the optimal injection gain, as most distortions in image fusion are caused by the extraction and injection of spatial detail. Both qualitative and quantitative metrics were utilized to evaluate the quality of the merged image. The mentioned metrics that were used commonly for evaluation of image fusion results support the proposed algorithm for image fusion as the output image was qualitatively and quantitatively growth. In the future the proposed method can be updated by increasing the objective function dimensions to two or three for getting a best fused image.
The universal motor, versatile and capable of running on both AC and DC sources, is utilized in various household appliances and power tools. This paper presents a featured methodology for analyzing a universal motor (UM) that does not have design data by extracting it via reverse engineering. These gained data were used to model the motor by Maxwell program and analyzing it by finite element method (FEM). Adopting the Maxwell program's drawing capability to design the square-shaped stator of a universal motor not part of the program library will also enable the Maxwell program to be widely used and unrestricted to use with particular motor designs. After modeling and solving the motor model, the performance characteristics of UM when operated with alternating current (AC) and direct current (DC) power supplies were investigated. The UM simulation results were compared with test results with good agreement. The success of a proposed methodology paved the way for the analysis of any electric motor included in the Maxwell program, even if this motor does not have design data.
A new technique is presented by which lateral outflows of material , from an oblique impact collision between wax projectile and a rigid surface , are collected to form a high speed single jet. This jet has been shown to be capable of producing cavities in semi-infinite target of wax in a manner similar to that produced in a hypervelocity impact situation. The produced jet capability of penetration is found to be maximum at higher velocities of impact , lower values of standoff and with projectiles having angle of obliquity in the range (â=20-25o). A preliminary theoretical model is also presented in an attempt to describe the process of jet creation and jet characteristics. The present technique is proved to be promising in simulating penetration of semi-infinite targets by the impact of high speed jet .
Progressive collapse is a partial or total failure of a building that mostly occurs when the build-ing loses primary structural elements (typically columns) due to accidental or natural hazards. The failure of structures due to an earthquake is one of the most important and frequent types of progressive collapse. In this study, the finite element method is used to assess the response of multistory reinforced concrete buildings subjected to column loss during an earthquake. Three-dimensional nonlinear dynamic analyses are carried out using SAP2000 V.20 program. The ef-fects of different parameters on the progressive collapse behavior are investigated, namely: the location of the removed column within the ground floor; the method of column removal (sudden, in two-steps, and in four-steps) and the removal timing during the earthquake. It is demonstrated that the collapse occurs when all or most of the hinges at the bases of the ground floor columns reach their collapse level. The chosen column removal timing and policy affect the structural behavior considerably. It is realized that, the risk of building collapse increases when the removal timing harmonizes with the peak ground acceleration timing. Based on the adopted earthquake characteristics and building configurations, it is found that, the two steps removal scenario is the most dangerous one.Keywords:Progressive collapse, Concrete buildings, Seismic load, Nonlinear dynamic analysis, Plastic hinge.© 2014
This study aims to improve different properties of sustainable self-compacting concrete SCC containing treated and modified polyethylene terephthalate PET fibers. For this purpose, gamma ray surface treatment and geometric modification were utilized for the used PET fibers. Concrete fresh properties include slump flow, T500mm, L-box and sieve segregation while mechanical properties include compressive, split tensile strength, flexural strength, static modulus of elasticity and impact strength. Further, physical properties and related durability properties comprise dry density, ultrasonic pulse velocity, porosity and water absorption. The results obtained demonstrated that the treatment and the modification used for the PET fibers slightly reduced the fresh properties of produced sustainable SCC (slump flow, T500 mm, L-Box and sieve segregation). However, they were within the limits of the SCC specification as reported in EFNERC guidelines. Further, concrete hardened properties in terms of compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, impact strength, ultrasonic pulse velocity, decrease in the dry density, decrease in porosity and water absorption increased significantly.
The status of the infrastructure of the transport system and then mobility in the governorate of Anbar is deplorable. Therefore, it requires two types of solutions in two phases. This study concerned with the first phase, which is represented by solving the problem of the inadequacy infrastructure in terms of availability between the cities, and work to develop it toward being maximally connected. So, generally speaking this study aimed to facilitate mobility through this network, by improving the accessibility in term of connectivity. The analysis process in this study, have twin objectives: first, to determine how much new linkages we need for our network to be maximally connected as a first stage? Second, Building a legislative framework lends the weight for decision makers in transport agency to take tough decision built up on ranking the new proposed linkages according to their relative values in providing access to the network, and the increment in comparable nodal accessibility due to the new additions. So, there is need for more sensible decisions based on more accurate analysis for deciding the optimum priorities for the new linkages to take place in the stage of development implementation via legislative framework. Therefore, the analysis will deal with topological characteristics for a number of aspects by expressing the simple graph of the network in a matrix format. These aspects are simulated and measured through the matrices powering process and the principles of graph theory. However, in addition to reducing the time the vehicles stays on the road, the study results will assist to divert a large proportion of the traffic volumes concurrently with the implementation process, and this in turn will pave the way to precede the solution of the second phase inside the cities. Not to mention, the legislative framework will bases for the financial framework of the transport agency. Keywords: infrastructure inadequacy& development, accessibility and connectivity, graph theory, matrix representation &powering, new linkage, nodal accessibility , relative value ,optimum priorities (ranking) and Decision making(legislation).
Matrix converters (MCs) have attracted significant interest and found extensive applications across multiple industries owing to their desirable characteristics. These include the capability to produce sinusoidal currents at both input and output, substantial size reduction, and enhanced reliability by minimizing significant passive components. This paper explores the potential of MC technology as a viable alternative to conventional AC-DC-AC converters in industrial applications. It discusses recent advancements in MC structural configurations, modulation/control algorithms, and multiphase structures and control systems. The paper offers an in-depth review of modern industrial uses of MC technology. It also delves into different methods for managing induction motors, particularly the DTC (Direct Torque Control) approach. The study explores the intricacies of DTC and its relationship with SVM. The primary research objective is to examine the performance of an IM when operated with an SVPWM inverter, focusing on harmonic analysis of voltages and currents. Various PWM methods regulate the voltage and frequency supplied to the IM. Sinusoidal Pulse Width Modulation (SPWM) and SVPWM are the two most commonly used 3-phase Voltage Source Inverter strategies. The growing adoption of SVPWM is driven by its ability to reduce harmonic content in voltage and enhance the fundamental output voltage of the IM. Consequently, this study models a DTC-SVM theory-driven IM using MATLAB/SIMULINK to control the speed of induction motors. The following values were calculated for the system: Quality factor=2.236, Damping ratio=4.45, and the cut-off frequency (fc=355.88H).
Hydraulic structures are structures submerged or partially submerged in water, they’re used to retain or divert natural water flow. Any hydraulic structure that retains water is faced with seep-age problems as the water seeks the path with the least resistance through or under the hydraulic structure. If the water carries materials as it flows or exerts high pressure on the floor of the structure, it will cause failures such as piping and cracks and there are many ways to prevent that, including cutoffs. In this paper, seepage is analyzed for different cases by using the empirical method (Khosla’s theory) and the numerical method by using computer software (SEEP/W). The results had some slight differences between the two methods as a result of not taking into ac-count the effect of soil characteristics of the empirical method. However, the water pressure heads underneath the impervious floor that calculated by the numerical method were greater
In the current article, an experimental investigation has been implemented of flow and heat transfer characteristics in a parabolic trough solar collector (PTSC) using both nano-fluids and artificial neural networks modeling. Water was used as a standard working fluid in order to compare with two different types of nano-fluid namely, nano-CuO /H2O and nano-TiO2/ H2O, both with a volume concentration of 0.02. The performance of the PTSC system was eval-uated using three main indicators: outlet water temperature, useful energy and thermal efficiency under the influence of mass flowrate ranging from 30 to 80 Lt/hr. In parallel, an artificial neural network (ANN) has been proposed to predict the thermal efficiency of PTSC depending on the experimental re-sults. An Artificial Neural Network (ANN) model consists of four inputs, one output parameter and two hidden layers, two neural network models (4-2-2-1) and (4-9-9-1) were built. The experimental results show that CuO/ H2O and TiO2/H2O have higher thermal performance than water. Overall, it was veri-fied that the maximum increase in thermal efficiency of TiO2/H2O and CuO/H2O compared to water was 7.12% and 19.2%, respectively. On the oth-er hand, the results of the model 4-9-9-1 of ANN provide a higher reliability and accuracy for predicting the Thermal efficiency than the model 4-2-2-1. The results revealed that the agreement in the thermal efficiency between the ANN analysis and the experimental results about of 91% and RMSE 3.951 for 4-9-9-1 and 86% and RMSE 5.278 for 4-2-21.
Recently, the sustainability issue has become crucial to operation, which motivates researchers to search for naturally generated, sustainable materials, especially in automotive applications outside of reduced prices and enhanced performance. Glass-linen/Polyvinyl Butyral hybrid composites' mechanical characteristics were examined in relation to the effect of linen fiber loading. The composite and hybrid composite samples of linen/glass fiber reinforced PVB film were created using a hot press with various layering patterns. The results were high impact values with increased both tensile and flexural strength values. Compared to other hybrid composites, the mechanical behaviors of the H1 (Glass / Linen) hybrid have a greater tensile strength measuring 401.30 MPa, while, H2 (Glass / Linen/ Glass) hybrids are found to have the highest flexural strength, measuring 160.80 MPa. An optical and scanning electron microscope morphological analysis on linen hybrid composites revealed good results. This indicated decreased rates of delamination between the fibers and matrix layers. The loading of the fibers was shown to have varying effects on the composite's mechanical behaviors. The linen/glass composites also demonstrated strong interfacial adhesion, which enabled the PVB-phenolic resin to penetrate the fiber bundles and produce a matrix with the good interlocking of the fibers
The extensive global competition between companies and the development of new industrial technologies have greatly contributed to the current competitive conditions Like industrial companies, customers demand high quality products, low prices and better performance. This fierce competition has led to concerns about improved product design. This development is based on GQFD. Model of this developed Water pump is employed by CAD solid model (version 7). In order to achieve competition and high quality and high performance in the Iraqi market. GQFD demonstrates the balance between product development and environmental protection. Used a water pump for a home air cooler as a case study. Data is collected and distributed using personal interview methods and questionnaire forms to indicate customer requirements. The data is then analyzed using Pareto chart and AHP to prioritize customer needs. These priorities are then placed in house of quality and matrix of relationships between customer requirements and technical characteristics is established. The product has been developed from electrical to mechanical, in addition to using accumulated, stored and recycled materials; it also saves 20% of energy, thereby combining energy reduction with the use of damaged materials and their re-entry into work. As a result, the cost of pump manufacturing will decrease
Natural convection heat transfer in two-dimensional region formed by constant heat flux horizontal flat tube concentrically located in cooled horizontal cylinder studied numerically. The model solved using the FLUENT CFD package. The numerical simulations covered a range of hydraulic radius ratio (5, 7.5, and 10) at orientation angles from (0o up to 90o). The results showed that the average Nusselt number increases with hydraulic radius ratio, orientation angles and Rayleigh number. As well as enhancement ratio for Nusselt number at orientation angle 90o and hydraulic radius ratio 7.5 equal 24.87%. Both the fluid flow and heat transfer characteristics for different cases are illustrated velocity vectors and temperature contours that obtained from the CFD code. The results for the average Nusselt numbers are compared with previous works and show good agreement.
In this paper, the hydraulic-thermal performance of a double-pipe heat exchanger equipped with 45°-helical ribs is numerically studied. The ribbed double-pipe heat exchanger is modelled using three heights (H = 0, 2.5, 3.75, 5 mm) of 45°-helical ribs. Two numbers (4-ribs and 8-ribs) of 45°-helical ribs are attached on the outer surface of the inner pipe of the counter-flow double-pipe heat exchanger and compared with a smooth double-pipe heat exchanger. Three-Dimensional computational fluid dynamics (CFD) model for a laminar forced annular flow is performed in order to study the characteristics of pressure drop and convective heat transfer. In addition, the influence of rib geometries and hydraulic flow behaviour on the thermal performance is system-atically considered in the evaluations. The annular cold flow is investigated with the range of Reynolds numbers from 100 to 1000, with three heights of ribs at the same width (W = 2 mm) and inclined angles of (θ = 45°).The results illustrate that the average Nusselt number and pressure drop increase with an in-creasing number of ribs, the height of ribs and Reynold number, while the friction factor decreas-es with increasing Reynolds numbers. The percentage of averaged Nusselt number enhancement for three rib heights (H = 2.5, 3.75 and 5 mm) at 4-ribs is (34%, 65% and 71%), respectively, While for 8-ribs the enhancement percentage is (48%, 87% and 133%) as compared with the smooth double-pipe heat exchanger at Re = 100. The best performance evaluation criteria of (PEC) at (8-ribs, and H = 5 mm) is 2.8 at Re = 750. The attached 45-helical ribs in the annulus path can generate kind of secondary flows, which enhance the fluid mixing operation between the hot surface of the annular gap and the cold fluid in the mid of the annulus, which lead to a high-temperature distribution. Increasing the height of 45°-helical ribs lead to an increase in the sur-face area subjecting to convective heat transfer.
In this paper, turbulent forced convection of nanofluid flow in channel with isoscelestriangularbaffles is numerically investigated over Reynolds number ranges of 5000-10000.One baffle mounted on the bottom wall of channel and another mounted on the top wall.Al2O3-water nanofluid with nanoparticles volume fraction of 4% and nanoparticles diametersof 25 nm is used. The governing continuity, momentum and energy equations as well as thelow Reynolds number k-ε model of Launder and Sharma have been solved using finitevolume method. The effect of baffle height, baffle distance as well as Reynolds number onthe flow and thermal characteristics have been presented and discussed. It is found that theenhancement ratio of the average Nusselt number as well as the fraction factor increase withincreasing in the baffles height. It is also found that the enhancement ratio of the averageNusselt number increases as the distance of top baffle decrease. Furthermore, the bestthermal-hydraulic performance of channel with triangular baffles using nanofluid can beobtained at baffle height of 2.5 mm, distance of the top baffle of 40 mm and Reynoldsnumber of 5000.
The antenna is a Modified Broadband Butterfly Antenna (MBBA). The technical parameters of such systems are heavily influenced by the qualities of the antenna feed devices. The aperture theory of antennas uses the representation of the radiation field of the antenna as a superposition of the fields of elementary sources, characterized by their type and amplitude-phase spatial distribution. The radiation field of an antenna of finite dimensions is a superposition of inhomogeneous spherical waves emitted by the antenna elements. This paper is primarily the study process, Radiation models were calculated using the model of the cavity plates, Simple Green model, and the strict commercial Electromagnetic Simulator. The modified active rectangular patches with the Gann diode were combined into arrays of E and H plane. Calculated and measured results for these two active arrays the beam scanning, the possibilities have been demonstrated for both arrays. The results of an electrodynamics numerical simulation were obtained. Broadband and multiband radio systems have already found widespread practical applications by utilizing basic antenna parameters and characteristics.