Six (1000*1000 mm2) slab specimens were cast and tested as two-way simply supported slabs previously (three under monotonic loading and three under repeated loading) are used in this research. The tested specimens consist of one solid slab and two voided slabs with the following variables (type of slab (solid and voided), presence of steel fibers (0% and 1%), and the presence of GFRP layers). This paper presents the results of tested slabs and the 3D-Nonlinear finite element (ABAQUS program) is proposed to verify the tested slabs under monotonic and repeated loading. The process of modeling the structure components of the tested slabs will be discussed in detail, including the creation of the parts, model mate
... Show MoreReactive powder concrete is an attractive new concrete technology for structural design applications. The technology has been used for different structures with several advantages. Strengthening and retrofitting structures using FRP has grown rapidly in the last decades to upgrade structures because of the gradual material degradation over time. The technique was applied mainly for conventional normal and high-strength concrete and steel. This study is conducted to study the performance of bonding interface among reactive powder concrete substrate and CFRP sheets using different parameters, including bond length, bond width, and bond–slip relations. Concrete prisms with dimensions of (25 x 25 x 75 mm) were adopted in t
... Show MoreThe study aimed to find the best amount of cellulose nanofibers to add to heat-cured denture base material to enhance its mechanical characteristics. Cellulose nanofibers (CNF) were added to the polymethyl methacrylate (PMMA) denture base in several weight percentages (0%, 0.5%, 1%, 1.5, and 2%). A probe sonicator was used to mix the monomer with the cellulose nanofibers for around 5 minutes. Impact strength, transverse strength, and shore D surface hardness were the three groups that were classified afterward according to the trials conducted. Descriptive statistics, including means, standard deviations, and bar chart visualisations, were utilised to analyse the data. The findings indicate that the mean values of impa
... Show MoreThe effect of the addition of sustainable materials and alkali-resistant glass fibers on perlite concrete is studied in this paper. The research includes slump, density, flexural strength, split tensile strength, compressive strength, and thermal conductivity tests. This specimen was cast using Portland cement, metakaolin (which replaced 15% of the cement weight as pozzolanic materials), a combination of coarse and fine perlite aggregate, superplasticizer, and local ash (which was employed as a filler and replaced by cement weight in a ratio of 10%). The ratio of cement to perlite (volumetric ratio) was 1:2. The concrete reinforced 1% alkali resistance glass fibers by volume of concrete. The results show that adding su
... Show MoreThis paper reports an experimental study regarding the influence of vertical oscillations on the natural convection heat transfer from a vertical channel. An experimental set-up was constructed and calibrated; the vertical channel was tested in atmosphere at 25o
C. The channel-to-ambient temperature difference was varied with the power supply to the electrical heater ranging between
15W to 70W divided into five levels. Data sets were measured under different operating condition from a test rig under six vibrating velocities (VVs) levels ranging from (5-30 m/s) in addition to the stationary state. The results show that the maximum heat transfer enhancement factor (E) occurs at Rayleigh number (Ra=2.328×103 ) and vibrational Reynol
Qaiyarah oil field is characterized by its complexity due to its extra heavy oil reaching 16° API. Thus, building a systematic PVT model for this field at a specific range of temperatures is a powerful challenge for screening such reservoirs. The peng-Robenson equation of state model with up to six pseudo components was developed for the crude sample of the Qaiyarah oil field. This work represents the fingerprint for constructing a dynamic model for the field under study. The model also applies to the heavy oil reservoirs under splitting and lumping scenarios. This work suggests a lumping scheme to enhance the accuracy and CPU performance of compositional reservoir simulations. Therefore, the full components model (13 c
... Show MoreSemi-deep foundations are a viable option when the soil under the foundation is loose and extended to a significant depth, also, when traditional methods of improvement are not feasible applying piles would not be a practical choice due to their high cost and time-consuming installation process. Skirted foundations are a sort of semi-deep foundation that can penetrate the soil to a depth that is twice their width. Skirted foundations, in which a vertical or inclined wall surrounds one or more sides of the soil mass under the footing, are recommended methods to increase the soil's bearing capacity. The walls work to reduce settlement while enhancing load capacity and failure depth in soils with low shear strength. This pa
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Reduction of noise and vibration in spur gear experimentally by using asymmetric teeth profiles with tip relief was presented. Both of classical (symmetric) and asymmetric (with and without tip relief) spur gears are used in this work. Gear test rig was constructed to achieve torsional vibration measuring, and two modified cutters are designed and manufactured to achieve tooth profile modifications. First to cut asymmetric gear tooth with pressure angles (14.5o/25 o) without tip relief for loaded and unloaded tooth sides respectively, and second to cut asymmetric gear tooth with pressure angles (14.5o/25 o) for loaded and unloaded tooth sides respectively with tip relief to ach
... Show MoreBiomimicry, as a way of thinking to go back to nature for inspiration, has its impact on many contemporary technological achievements. Some of them are used to design and construct kinetic facades in architecture, because of the importance role of facades in reducing sun radiation, that enter the building through using shading systems and components. In light of this, research problem is determined: "Do technologies which are inspired by biomimicry effect shading in kinetic facades through its characteristics in materials and the mechanics. So the research identifies its goal as: "To identify the types of kinetic facades in buildings and their characteristics as materials and shading mechanism associated with the b
... Show MoreThe removal of fluoride ions from aqueous solution onto algal biomass as biosorbent in batch and continuous fluidized bed systems was studied. Batch system was used to study the effects of process parameters such as, pH (2-3.5), influent fluoride ions concentration (10- 50 mg/l), algal biomass dose (0–1.5 g/ 200 ml solution), to determine the best operating conditions. These conditions were pH=2.5, influent fluoride ions concentration= 10 mg/l, and algal biomass dose=3.5 mg/l. While, in continuous fluidized bed system, different operating conditions were used; flow rate (0.667- 0.800 l/min), bed depth (8-15 cm) corresponded to bed weight of (80- 150 g). The results show that the breakthrough time increases with the inc
... Show MoreThis research presents a new study in reactive distillation by using consecutive reaction: the saponification reaction of diethyl adipate (DA) with sodium hydroxide solution .
The effect of three parameters were studied through a design of experiments applying 23 factorial design . These parameters were : the mole ratio of DA to NaOH solution (0.1 and 1) , NaOH solution concentration (3 N and 8 N) , and batch time (1.5 hr. and 3.5 hr.) . The conversion of DA to sodium monoethyladipate(SMA)(intermediate product) was the effect of these parameters which was detected . Also , the percentage purity of the intermediate product was recorded . The results showed that increasing mole ratio of DA to NaOHsolutio
... Show MoreGypseous Soils are distributed in many regions in the world including Iraq, which cover about (31.7%) of the surface area of the country. Existence of these soils, some times with high gypsum content, caused difficult problems to the buildings and strategic projects due to dissolution and leaching of the gypsum slates by the action of water flow through the soil mass. In this study the effect of treatment with Dihydrate Calcium Chloride (CaCl2.2H2O) as water solution on compaction, compressibility, leaching, permeability and shear strength characteristics of Gypseous soil is investigated. It is found that the maximum dry unit weight increases while optimum moisture content decreases with the increase in the concentration of calcium chlor
... Show MoreBy adding a measure of third harmonic to the output of each phase of three-phase inverter, it is possible to obtain a line-to-line output voltage that is 15 percent greater than that obtainable when pure sinusoidal modulation is employed.
The line-to-line voltage is undistorted. The method permits the inverter to deliver an output voltage approximately equal to the voltage of the ac supply to the inverter. Thus an induction motor of standard rating with respect to the ac supply to the inverter can deliver very nearly full power at rated speed when supplied from the inverter. This is achieved without pulse dropping or any other form of mode changing.
يعد مبدأ التكامل البيئي- الاجتماعي - الجمالي من المبادىء المهمة في تصميم المجمعات السكنية لنمط متعدد الاسر لما
لها من اهمية في وقتنا الحالي بسبب تفاقم ازمة السكن ، وللوصول الى تصاميم تقترب من نمط الاسكان منفرد الاسرة ، مع
الاخذ بالمعلومات والمعطيات والحلول الناجعة والمتراكمة عبر خبرات سنين طويلة والموجودة في تراثنا العربي للمحلة السكنية
التقليدية، على هذا الاساس اعتمد البحث في تقديمه للمشكلة البحثية
The behavior of prestressed concrete box-girder bridges has been studied under short term loading.
The 20-noded isoparametric three-dimensional brick elements have been used to model the concrete
in the box-girder with its two cantilever flanges. The reinforcing bars are idealized as axial
members embedded within the brick elements. The behavior of concrete in compression was
simulated by an elastic-plastic work hardening model followed by a perfectly plastic response,
which is terminated at the onset of crushing. In tension, a smeared crack model with fixed
orthogonal cracks is used with the inclusion of models for the retained post-cracking stress and
reduced shear modulus. The prestressing forces in the tendons ar
The need of higher powers in electrical drives has forced the researchers to develop new power source possibilities. Multilevel inverters have been presented as a cost effective solution for various high voltage and high power applications including power quality and motor drive problems. The traditional pulse width modulated (PWM) Inverter does not completely eliminate the unwanted
harmonics in the output waveform. Using the multilevel inverter as an alternative to traditional PWM inverters for electric motor drive applications is investigated. The concept of the Optimized Harmonic Elimination Stepped-Waveform (OHESW) technique for a multilevel inverter is presented. The effectiveness of this technique in minimizing the inverter swi
The present work studied the drop size distribution in the RTL contactor using two liquid-liquid systems, xylene-acetone-water and kerosene-acetone-water. Process variables studied were: rpm (10-50 min-1), continuous phase flow rate (4-12 l/h), dispersed phase flow rate (4-12 l/h), and concentration (0.1-0.5 mole/l). It was found that Sauter mean drop diameter (d32) decreased with increasing rpm and continuous phase flow rate, and decreasing dispersed phase flow rate and concentration. An empirical correlation, with a correlation coefficient equal to (92.6%), relating d32 with process variables was developed having the form:
Experiments were carried out to study the local and average heat transfer by natural convection in
a vertical concentric cylindrical annulus. The experimental setup consists of an annulus has a radius ratio of 0.555 and inner cylinder with a heated length 1.2m subjected to the constant heat flux while the outer cylinder is subjected to the ambient temperature. The investigation covers heat flux range from 58.2 W/m2 to 274.31 W/m2. Results show an increase in the natural convection as heat flux increases leads to an improve in the heat transfer process. An empirical equation of average Nusselt number as a function of Raylieh number was deduced
In this study, the dynamic modeling and step input tracking control of single flexible link is studied. The Lagrange-assumed modes approach is applied to get the dynamic model of a planner single link manipulator. A Step input tracking controller is suggested by utilizing the hybrid controller approach to overcome the problem of vibration of tip position through motion which is a characteristic of the flexible link system. The first controller is a modified version of the proportional-derivative (PD) rigid controller to track the hub position while sliding mode (SM) control is used for vibration damping. Also, a second controller (a fuzzy logic based proportional-integral plus derivative (PI+D) control scheme) is developed for both vibra
... Show MoreAn experimental model is used to simulate the loss of soil lateral confinement due to excavation nearby an individual axially loaded pile. The effects of various parameters, such as the horizontal distance of excavation, depth of excavation and pile slenderness ratios are investigated. The experimental analysis results showed the effect of excavation is more remarkable as the horizontal distance of excavation becomes closer to the pile than half pile length. The effect of excavation diminishes gradually as the horizontal distance increases beyond that distance for all the investigated pile slenderness ratios and depths of excavation. The pile head deflection, settlement and bending moments along pile increase with decreasing horizontal d
... Show MoreThe simulation have been made for 3D flow structure and heat transfer with and without
longitudinal riblet upstream of leading edge vane endwall junction of first stage nozzle guide vane .The research explores concept of weakening the secondary flows and reducing their harmful effects.Numerical investigation involved examination of the secondary flows ,velocity and heat transfer rates by solving the governing equations (continuity, Navier -stokes and energy equations ) using the known package FLUENT version (12.1).The governing equations were solved for three dimentional, turbulent flowe, incompressible with an appropriate turbulent model (k-ω,SST) .The numerical solution was carried out for 25 mode
... Show MoreThe Aim of this paper is to investigate numerically the simulation of ice melting in one and two dimension using the cell-centered finite volume method. The mathematical model is based on the heat conduction equation associated with a fixed grid, latent heat source approach. The fully implicit time scheme is selected to represent the time discretization. The ice conductivity is chosen
to be the value of the approximated conductivity at the interface between adjacent ice and water control volumes. The predicted temperature distribution, percentage melt fraction, interface location and its velocity is compared with those obtained from the exact analytical solution. A good agreement is obtained when comparing the numerical results of one
The results of theoretical and experimental investigations carried out to study the effect of load and relative sliding speed on the abrasive wear behavior in drilling bit teeth surfaces of an insert tungsten carbide bit have been presented. Experimentally, an apparatus for abrasive wear tests conducted on the modified ASTM-G65 was modified and fabricated to facilitate loading and measurement of wear rate for the sand/ steel wheel abrasion test, which involves two cases of contact; first is at dry sand and second is under wet condition. These tests have been carried under varied operating parameters of normal load and sliding speed. A theoretical model based upon the Archard equation has been developed for predicting wear simulation by u
... Show MoreInternet paths sharing the same congested link can be identified using several shared congestion detection techniques. The new detection technique which is proposed in this paper depends on the previous novel technique (delay correlation with wavelet denoising (DCW) with new denoising method called Discrete Multiwavelet Transform (DMWT) as signal denoising to separate between queuing delay caused by network congestion and delay caused by various other delay variations. The new detection technique provides faster convergence (3 to 5 seconds less than previous novel technique) while using fewer probe packets approximately half numbers than the previous novel technique, so it will reduce the overload on the network caused by probe packets.
... Show MoreThe aim of this work is oriented to increase film cooling effectiveness value through numerical investigations for flow of Mach number not more than 0.3 around vane surface, to find the effects of inclination and compounds angles of round holes in staggered rows on adiabatic film cooling effectiveness of vane suction side. Multi cylindrical film cooling hole cases were studied with pitch ratio P/d =2 and 3, local blowing ratios M=0.382, 0.77 and 1.14, inclination angles a=30° and 45°, compound angles β= 0°, 15°, 30° and 45° and local momentum ratios I= 0.084, 0.34 and 0.756 for better cooling process.
A numerica
... Show MoreA study was performed to evaluate heavy metals removal from sewage sludge using lime. The processes of stabilization using alkaline chemicals operating on a simple principle of raising pH to 12 or higher, with sufficient mixing and suitable contact time to ensure that immobilization can reduce heavy metals. A 0.157 m3 tank was designed to treat Al-Rustemeyia wastewater treatment plant sludge. Characteristics of raw sludge were examined through two parameters: pH and heavy metal analysis. Different lime doses of (0- 25) g CaO/100 g sludge were mixed manually with raw sludge in a rotating drum. The samples were analyzed two hours after mixing. pH and heavy metals results were compared with EPA and National Iraqi Stand
... Show MoreThe authentic traditional architecture proved that it is very convenient to the environmental and social regulations where it appeared and lasted for hundred of years.
This traditional architecture got the intelligence in providing thermal comfort for their occupants by the intelligent usage of the building materials and the intelligent planning and designs which took in consideration the climatic condition and the aerodynamics of the whole city as one ecological system starting from the cold breeze passing through its narrow streets till it enters the dwelling units and glides out through the wind catchers.
This architecture had been neglected and replaced by modern imported architecture which had collap
... Show MoreIn recent years, the performance of Spatial Data Infrastructures for governments and companies is a task that has gained ample attention. Different categories of geospatial data such as digital maps, coordinates, web maps, aerial and satellite images, etc., are required to realize the geospatial data components of Spatial Data Infrastructures. In general, there are two distinct types of geospatial data sources exist over the Internet: formal and informal data sources. Despite the growth of informal geospatial data sources, the integration between different free sources is not being achieved effectively. The adoption of this task can be considered the main advantage of this research. This article addresses the research question of how the
... Show MoreThe present study addresses the behavior of gases in cultivation media as an essential factor to develop the relationship between the microorganisms that are present in the same environment. This relationship was explained via mass transfer of those gases to be a reasonable driving force in changing biological trends. Stripping and dissolution of oxygen and carbon dioxide in water and dairy wastewater were investigated in this study. Bubble column bioreactor under thermal control system was constructed and used for these processes. The experimental results showed that the removal of gases from the culture media requires more time than the dissolution. For example, the volumetric mass transfer coefficient for the removal
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