Journal of Engineering and Sustainable Development (JEASD)

This paper presents the results of experimental program investigating the effect of fire flame (high temperature) on the structural performance of bubble slabs. The program consisted casting and testing nine specimens. The dimensions of the specimens were 270 X 500mm in plane and with two different thicknesses; 90 and 140mm. All specimens were cast with normal concrete of approximately 25 MPa compressive strength. Seven specimens were burnt using a diesel furnace and two specimens were kept without burning as controls. The test parameters were; the fire flame temperature (200, 500, and 800 oC), the cooling method is processed gradually by left the slabs in the air or suddenly by using water, the exposure time (1, 1.5, and 2 hours), and thickness of slabs (90 and 140mm). After cooling, the specimens were simply supported in one direction and tested under a uniform load applied gradually till failure. The test results showed that, the residual strength of specimens decreased from 71.8% to 21.6% and their central deflection increased with increasing the fire flame temperature from 200 to 800 oC and exposure time from 1 to 2 hours.

This study was carried out to study the effect of silver and oxide zirconium – oil nanofluids on enhancement heat transfer in a heat exchanger with and without fins by changing flow direction. This study was done by changing the parallel flow configuration into counter flow configuration under laminar flow regime. The properties of nanofluids (density, viscosity, thermal conductivity and specific heat) are practically measured. The two types of nanofluids at 1%, 2%, 3%, 4% and 5% particle volume concentration were prepared by two step method. The nanofluid was applied in a heat exchanger with and without fins to enhance heat transfer. The measured results show that silver with oil nanofluid gives maximum heat transfer enhancement compared with oxide zirconium nanofluid used. The presence of Ag and ZrO2 nanoparticles attributes to the generation of strong nanoconvection current and better mixing. The effect of different parameters such as flow Reynolds number, nanofluid temperature, concentration and type of nanoparticle on heat transfer coefficient and pressure drop of the flow are studied.

The present work deals with the effect of the magnetic field on the performance of (spark ignition engine). Thermal efficiency, brake specific fuel consumption (bsfc) and exhaust emissions were measured for Iraqi gasoline which has octane number of (83). The fuel was subjected to a magnetic field of (1000 and 2000 Gauss), respectively. The magnetic field was placed on fuel supply line to magnetize the fuel before admitting it to the carburetor. Mercedis Benz SI engine, 4 strokes, and 4 cylinders were used in this study under engine speed ranging between (2000 to 3500 rpm) at maximum load.A reduction in fuel consumption up to (2.19%) and (5.488%), brake thermal efficiency rose by about (4.7%) and (13.5%), for one and two magnets, respectively. The exhaust gas emissions showed a reduction in CO nearly by (3.7%) and (6.9%), CO2 up to (3.43%) and (9.2%). However the exhaust temperature increased up to (1.7%) and (3.65%) for the two magnets values, respectively.

Adsorption removal of Cu(II) and Cd(II) from aqueous solution using low-cost banana peels (food waste) and bentonite clay (natural resource), was investigated. The adsorption process was studied in a batch scale at mean operation parameter which were pH, adsorbent particle size, adsorbents dosages, and initial concentrations of metal ions. All experiments were conducted at room temperature. Langmuir and Freundlich adsorption isotherm models were achieved to describe the quantitative uptake of Cu(II) and Cd(II) ions by adsorbates. The results show that the maximum adsorption removal reach to 80% and 99.5% for Cu(II) on to banana peels and bentonite, respectively and 77 % and 98% for Cd (II) onto banana peels and bentonite respectively at optimum operating conditions: pH 5, particle size 75µm,adsorbent dosage 2g/100ml and metal concentration 5 mg/L .The equilibrium adsorption data for Cu(II) and Cd(II) were better fitted to Freundlich adsorption isotherm model than Langmuir..

Triaxial accelerometers are used in various applications, such as inertial navigation systems (INSs) and inclinometers. Such accelerometers must be calibrated as accurately as possible because accelerometers with even small biases could result in a very fast position drift when they are used for INS applications and could result in inaccurate tilt angle measurements. Since the calibration parameters of a triaxial accelerometer vary under different environmental conditions, including temperature change, the gain factors and biases change whenever the sensor is switched on. Thus, an accelerometer must be calibrated before use or when the temperature is significantly changed. This paper presents a triaxial accelerometer calibration method using a mathematical model of nine calibration parameters: three gain factors, three biases and three non orthogonality factors. The fundamental principle of the proposed calibration method is that the sum of the triaxial accelerometer outputs is equal to the gravity vector when the accelerometer is stationary. The proposed method requires the triaxial accelerometer to be placed in forty eight tilt angles to estimate the nine calibration parameters. Since the mathematical model of the calibration parameters is nonlinear, an iterative method is used Levenberg-marquardt algorithm (LMA).

To solve the problems of digital image processing for mapping, surveillance, recognition, video transmission and other areas used the image compression techniques. One way of image compression is image segmentation, there are number of segmentation methods based on the division and merging areas, which are widespread due the relative ease of implementation. The disadvantage of these methods is the appearance of segmentation faults structurally complex areas of pixels and lack of adaptation to the constraints of computational-enforcement resources, computation time and the vulnerability against changing brightness and contrast and weakness via the noise effect.

In this work, focus is taken on developing a waste heat recovery system for capturing potential of exhaust heat from an air conditioner unit to be reused later. This system has the ability to store heat in phase change material (PCM) and then release it to a discharge water system when required. To achieve this goal, a Finned, Water-PCM, Double tube (FWD) system has been developed and tested. Different profiles of fins attached to the (FWD) system have been investigated for increasing the thermal conductivity of the PCM. These include using Circular Finned, Water-PCM, Double tube (CFWD) system; Longitudinal Finned, Water-PCM, Double tube (LFWD) system; Spiral Finned, Water-PCM, Double tube (SFWD) system; as well as; Without Fins, Water-PCM, Double tube (WFWD) system. An experimental test rig that attached to an air-conditioner unit has been built to include 32 tubes of the FWD systems for both vertical and horizontal layouts during charging and water discharging processes. Transient 3-D, numerical simulations using (ANSYS Fluent14.0 software) have been developed to predict the thermal behavior for all types of FWD systems under investigation.

Attendance is an important aspect in every educational institute or workplace. Most universities are still using the paper based attendance system. This paper presents an effective approach to improve the processes of attendance system using Radio Frequency Identification (RFID) technology.The design of software tools was implemented by using Visual Basic 6.0 for interfacing and a database for persons’ information include RFID tags identification (IDs). The proposed design has Liquid Crystal Display (LCD) to get message from the application when the identification is done, and pass information back to the micro controller to send this information to LCD to be displayed.

In this study, a total of twenty four vibrated and self-compacting concrete (SCC) corbels with normal and high compressive strength have been cast and tested under vertical loading. All corbels had the same main steel area. Twelve of these were tested under monotonic loading until failure with the following variables: shear span to effective depth ratio, amount of the secondary reinforcement (horizontal stirrups bars), strength of concrete (normal and high strength) and the type of concrete (vibrated and SCC). Test results indicate that the use of SCC in corbels, results in improving the behavior and shear strength of the specimens from (8.2% to 14.2%).For vibrated normal and high strength concrete, it was found that when the shear span to effective depth ratio is decreased an increase occurs in cracking and ultimate loads.

Shear, Deep beam, box beam, strengthening, NSC, SCC, Rib

An accurate estimation of Manning's roughness coefficient is of vital importance in any hydraulic study including open channel flow. There are empirical methods to estimate the values of roughness however these methods are often applicable to a narrow range of river conditions. In the present study, field work, laboratory work and an intelligent method based on Adaptive Neuro- Fuzzy Inference System ANFIS approach model are applied to Al- Diwaniya river as a case study to estimate the values of Manning's coefficient through direct method using discharge, particle size, hydraulic radius, and slope of river. The data are measured in the field (river) for the period from 1/11/2013 to 28/2/2014 and divided randomly into two sets; the first set is for training purposes; the second set is for testing purposes. Statistic measurements are then used to evaluate the performance of the models. Based on the comparison of the results, it is well found that the ANFIS model presented better estimation than the other empirical relationships considered here. Also, a sensitivity analysis showed that d90 has greater influence on Manning coefficient than the other independent parameters in ANFIS model.

The structural rehabilitation of reinforced lightweight aggregate concrete beams in shear was studied with resin injection. A series of model beams, reinforced in shear, were loaded in the laboratory until failure, repair and again loaded to failure .The variables in the test program were shear span-to-depth ratio , 4.0,3.0,2.5,2.0,1.5 and 1.0 ; and shear reinforcement index ,ρvfy= 0.493,0.704 and 0.896 MPa. Experimental failure loads are compared with predictions using ACI 318M-02 code and the modified compression field theory by the program of “Response 2000” .After testing ,the beams failed due to new diagonal cracks .The ratio of ultimate load to crack load varies from 1.5 for a/d >2 to 2.27 for a/d ≤ 2 (deep beams) .Test results indicate the ACI 318M-02 is conservative .

This paper has been studied the effect of shot peening to improve the mechanical properties, especially the enhancement of fatigue life, also to study the effect of shot peening on notch sensitivity factor (q) for two kinds of notched circular cross-sectional area of (AA7075-T6) with radii of notches (1, 1.25 mm). Due to the dimensions of specimens and notch radius, the stresses concentration factors Kt were (1.62, 1.73), respectively. This paper was included the effect of compressive residual stresses on the Neuber characteristic length (ρ).The experiments of shot peening were carried out at two different shot peening times (SPT) (0, 8, 10, 12, 20 min). The tensile test after shot peening was done to know the improvement in mechanical properties, The surface roughness, microhardness, and the compressive residual stresses by X-ray diffraction (XRD) were measured. The results showed the maximum decreasing in notch sensitivity factor (22.35 %) and maximum increasing in Neuber characteristic length which was (270.2%) at the same shot peening time (10 min) and notch radius (1.25 mm).

This work presents a theoretical analysis for the prediction of refrigerant saturation temperature inside a typical solar two-phase loop. This loop may be incorporated in any solar heating system for transporting heat between the solar collector and storage tank. The procedure takes into account all influencing parameters such as:- solar irradiance, ambient temperature, heat transfer coefficients in the source (collector) and sink (condenser), collector fill ratio and the geometric parameters of the solar collector and condenser.The trend of change of saturation temperature was studied over a typical daytime period extending 8 hours. Mathematical models were formulated for the collector and condenser to take into account the most influencing parameters. The models are highly interrelated which required an iterative procedure. A computer program was built to implement the iterative procedure and simulate the change of saturation temperature during the studied period. The period was divided into small time intervals of 10 seconds.Results reveal a significant influence of condenser area, collector fill ratio and the working conditions on the calculated saturation temperature.

A strengthen method that was used quite extensively during the mid 1970s is steel plate bonding, this method has gained renaissance in the last decades. This paper presents experimental work includes investigation of four simply supported reinforced concreate beams under pure torsion. The first beam was the control beam without strengthening. The other three beams were strengthened externally by bolted steel plates. The most important variable was the spacing between shear connectors.The discussion of results are based on torque-twist behavior, beam longitudinal elongation behavior and the influence of the spacing between shear connectors on cracking torque, ultimate torque and failure modes.

The research is a theoretical study of heat transfer and pressure drop of two phase flow of refrigerants during condensation in horizontal tube banks and air flows across them in parallel direction under constant heat flux . (R134a) has been selected as a working fluid which is environment-friendly and is used as an alternative to (R12) in air conditioning and refrigeration systems and others industrial applications. The effects of different variables on the heat transfer operation and pressure drop were investigated, namely, air velocity ,air temperature, tube diameter, and the number of rows and columns of the tubes in addition to longitudinal and transversal pitch ratio . A computer program is built to calculate the heat transfer coefficient and pressure drop through condensation process using Finite Difference scheme. Engineering Equation Solver (EES) was employed as an assistant program to estimate physical and thermal properties of different refrigerant. Results showed a drop in pressure along the pipe , its value was decreased with increasing the tube diameter, air temperature and the transversal pitch in both in-line and staggered arrangements as well as the longitudinal pitch in staggered arrangement . Also the heat transfer coefficient between the fluid and the internal tube surface decreases along the tube length and increases with both of the number of tubes in rows and columns air velocity and longitudinal pitch in in-line arrangement. The results showed that the tube banks of staggered arrangement has a higher heat transfer coefficient than the in-line arrangement tube banks .