DIYALA JOURNAL OF ENGINEERING SCIENCES

A numerical study on the performance of the
nano-scale antenna based on VeeYagi-Uda
geometry that is constructed from Nano ShellSilver Coated Silica (NSSCS) chains is
investigated for tunable solid-state laser
applications. In this study, a Finite Integral
Technique (FIT) based on the formulations of
Computer Simulator Technology-MicroWave
Studio (CST MWS) software package is invoked
to evaluate the antenna parameters such as:
Reflection coefficient (S11), gain/ directivity, and
directivity. Before conducting the simulation
study, the refractive index properties of the
NSSCS are evaluated according to Lorentz
distribution function of a hetero-structure
junction. The proposed antenna shows three
resonance modes at 75 THz, and 175 THz, and
266 THz. It is found the best antenna matching,
S11<-10dB, at 75 THz and 175 THz about -23 dB
and -15 dB, respectively. However, at 266 THz,
it is found -3 dB in max. The antenna shows
acceptable gain values at the three considered
frequencies about 2.5 dBi, 3.5 dBi, and 2 dBi,
consistently. Therefore, the antenna exhibits a
high directivity at 175 THz and 266 THz in
comparison to the first mode at 75 THz. Next, a
matching circuit is coupled to a nano-circuitry to
tune antenna around 175 THz. The maximum
emitted electric field is found to be around 175
THz. Finally, it is found that the introduction of
the matching circuit has a significant tuning
ability on the second mode at 175 THz; however,
at the other two modes the tuning does not show
a significant change.

The purpose of the present study is to investigate the effect of ambient air temperature on the performance of spark ignition engine, and exhaust gas temperature. Various factors taken that affects the performance of four-stroke petrol engine. An experimentalstudy is carried out to investigate engine performance parameters. The experimental results demonstrate that the method proposed to measure the intake ambient air temperature at different engine speeds. The different ambient air temperature was taken (10,20, 30, 40 and 50°C) at different climate conditions and in the different engine speeds (1500, 2000 and2500 r.pm). The results of experimental shows that increasing ambient air temperature will improve the fuel consumption and thermal efficiency about (14%-16%) consecutively. It is also shows decrease in the volumetric efficiency with increasing ambient air temperature. However, by increasing sucked air temperature, will lead to increase exhaust gas temperature.

A study, on the contact stresses and inter-laminate stress distributions in laminated leaf springs, is presented in this research. Several configurations and models of leaf springs are analyzed by finite element method. The aim is to find a configuration, which provides minimum values of contact stresses and inter-laminate stresses, for the same spring constant and load-deflection response. Results of the analyses show that making certain types of cuts in leaf springs could provide better designs than original unmodified springs, and leads to reduction in contact and inter-laminate stresses. This reduction in stresses is expected to increase the service life of leaf springs.

This paper studied the application of 2-D Plaxis (v8.6, 2011) software on a pavement layer structure set on unsaturated subgrade soil. An axisymmetric finite element (FE) model was used to analyze the behavior of pavement layers subjected to dynamic loadings. The model was loaded with an incremental contact pressure from 50 to 550 kPa with different variable such as water table level (1,2 and 3m), suction of soil and degree of saturation (100, 90, 80, 70 and 20%). The results indicated that during loading on pavement layer with increases water table level and different degree of saturation the vertical settlement was decreased by about (11, 15, and 18%) for water table level= 1m, (9, 13, 16%) for water table level= 2m and (28%) for water table level= 3m (drysoil) respectively.The effect of degree of saturation on the vertical settlementis apparent at the lower value for water table level (1 and 2m) and the vertical settlementis decreased with increasing soil suction. The results also show the negative pore water pressure decreased with decreased of degree of saturation and development increases with depth and beginning of dynamic load. The effect of unsaturation greater at the center line of pavement layer and limited far away the center line.

Due to the urgent need to make maximum use of electrical power generated from the Photo-Voltaic System (PVS) solar panels, several techniques have been developed for this purpose. Maximum Power Point Tracking (MPPT) algorithm raises the efficiency of PVS’s. Simulation of the complete (PVS) possesses the ability of MPPT is present in this paper. The approved PVS consists of a PV array,DC-DC Boost Converter and MPPT algorithm using Incremental Conductance Method (INC). All parts of the system were simulated programmatically using MATLAB. The obtained Results showed the efficiency of the algorithm used to extract the maximum power regardless of changes in solar radiationand cell’s temperature.

This paper presented the effect of bending on multi-layer of hollow columns of Hybrid materials (Carbon-Glass /epoxy-Alumina) composite this effect occurred and volume fraction of fibers. An experimental procedure was developed to study the performance of these effects under bending load using a hydraulic bending device type (MATEST. SRL) testing machine. This study has three forms through the selection of columns hollows width to thickness (a/b) (0.5, 1 and 2) with three types of layers of samples (2,4 and8) layers. The ultimate load of failure for each Hybrid/epoxy-Al2O3had been determined and specified the optimum volume fraction (Vf) due to the effect of mixing 50% and 60% were low in the case for compared 55% volume fraction. To simulate this problem the researcher used Explicit Mesh for AUTODYN under ANSYS-15 software, it was found that maximum bending load for Hybrid/ Epoxy-Al2O3 Specimens, the maximum load of specimens increased with increasing number of layers from 2L to 8L. The results also identified that the maximum load capacity by 55% volume fraction and a/b=0.5 of all compositespecimens was highest from the others types of (50% and 60%) volume fractions and (a/b=1 and a/b=2) .Also, the Increasing ratio of stress capacity for specimens have 4 to 2 layers (4/2) and 8 to 4 (8/4) for experimental results have maximum value with increasing by 48.19% and 46.84% at (Sp.4#8/Sp.2#4) and (Sp.8#6/Sp.4#6) respectively

This paper presents a collision-free path planning approaches based on Bézier curve and A-star algorithm for robot manipulator system. The main problem of this work is to finding a feasible collision path planning from initial point to final point to transport the robot arm from the preliminary to the very last within the presence of obstacles, a sequence of joint angles alongside the path have to be determined. To solve this problem several algorithms have been presented among which it can be mention such as Bug algorithms, A-Star algorithms, potential field algorithms, Bézier curve algorithm and intelligent algorithms. In this paper obstacleavoidance algorithms were proposed Bézier and A-Star algorithms, through theoretical studies and simulations with several different cases, it's found verify the effectiveness of the methods suggested. It's founded the Bézier algorithm is smoothing accurate, and effective as compare with the A-star algorithm, but A-star is near to shortest and optimal path to free collision avoidance. The time taken and the elapsed time to traverse from its starting position and to reach the goal are recorded the tabulated results show that the elapsed time with different cases to traverse from the start location to destination using A-star Algorithm is much less as compared to the time taken by the robot using Bézier Algorithm to trace the same path. The robot used was the Lab-Voltof5DOF Servo Robot System Model 5250 (RoboCIM5250).

This work demonstrates the simulation of two different types of optical fiber amplifiers (OFA) utilizing OptiSystem–10, namely, 3 m length of erbium doped fiber amplifier (EDFA) and 7 km length of Raman fiber amplifier (RFA). The counter-pumped architecture is adopted for both proposed optical amplifiers. The optimum pump power (OPP) for each amplifier determines in which the longest 3–dB flat gain bandwidth (3–dB BW), reasonable average gain level (Gav), proper average noise figure (NFav) and lower gain variation (Gvar) were achieved. The EDFA shows best performance at conventional band (C–band) within the pump power of 30 mW.While the better performance is observed at long band (L–band) within the pump power of 600 mW for the RFA

Using Bubbles in the slab is a revolutionary method of eliminating concrete from the middle of conventional slab as this concrete does not perform any structural function, thereby dramatically reducing structural dead weight. This research presents experimental study to investigate the effect of construction type on the strength and behaviour of bubbled one-way slabs. The experimental program consists of testing four slabs with dimensionsof 1850mm×460mm×110mm. One1of the tested slabs was conventional slab (without bubbles), two bubbled slabs with different types of construction (simple and filigree bubbled slabs) and the remaining one is filigree bubbled slab strengthened with steel cage. The bubbles were made of recycled plastic balls. The experimental results show that the stiffness reduction factor for all the bubbled slabs was (0.87), this leads to decrease the ultimate strength of bubbled slabs and to be smaller than that of the solid slab by 4.4% 69% and 1.7% respectively. Also an increase in deflection at yield load (∆y) by about (10% to 12%), at the same time the crack load is found to be decreased by (13% to 40%). The simple bubbled slab is more efficient when compared with filigree bubbled slab. Also the results show that the use of steel cage in filigree bubbled slab gives an increase in the ultimate load by 69% and an increase in the ultimate deflection by about 77% when compared with filigree bubbled slab without steel cage.

Reinforced concrete wide beams (WBS) have beenused in construction buildingsbecause its provide manyadvantages; reducing thereinforcement congestion, reducing the quantity of the required formwork, providing simplicity for replication, and decreasing the storey height. The current study presents the results of four full-scale wide RC beams in order to study their shear behavior and investigate the effectiveness of carbon fiber reinforced polymer (CFRP) when using as shear reinforcement to improve the shear capacity of wide RC beams, one these beams was fabricated by (ANSYS) program this beam was unstrengthened with CFRP and without stirrups (control beam), the other two beams was strengthened with vertical and inclined CFRP sheet without stirrups and the last beam reinforced with shear stirrups (WBS). All beams casted with normal concrete strength (30 MPa), simply supported and under two point loads. The performances of these beams were measured in terms of; ultimate load, crack patterns, concrete and steel strains, deflection, and mode of failure. The results showed an increasing in ultimate load of strengthened beams with inclined, vertical CFRP and beam with shear reinforcement by (19.9%), (7.14%) and (39.8%) respectively as compared with the control beam, and this results means possibility of replacing the internal shear reinforcement with externally bonded CFRP.

The aim of this paper is to control the flow separation above backward-facing step (BFS) airfoil type NACA 0015 by blowing method. The flow field over airfoil has been studied both experimentally and computationally. The study was divided into two parts: a practical study through which NACA 0015 type with a backward -facing step (located at 44.4% c from leading edge) on the upper surface containing blowing holes parallel to the airfoil chord was used. The tests were done over two-dimensional airfoil in an open circuit suction subsonic wind tunnelwith flow velocity 25m/s to obtain the pressure distribution coefficients. A numerical study was done by using ANSYS Fluent software version 16.0 on three models of NACA 0015, the first one has backward-facing step without blowing, the second with single blowing holes and the third have multi blowing holes technique. Both studies (experimental and numerical) were done at low Reynolds number (Re=4.4x105) and all models have chord length 0.27m.The experimental investigations and CFD simulations have been performed on the same geometry dimensions, it has been observed that the flow separation on the airfoil can be delayed by using velocity blowing (30m/s) on the upper surface. The multi blowing holes with velocity improved the aerodynamics properties.The multi blowing holes and single blowing holethesame effect onpressure distribution coefficients.

Third generation partnership project (3GPP) has been introducing The Long Term Evolution (LTE) (release8) and LTE advance (LTE-A) (release 10)fourth generations as a new access technology to mobile communication in order to meet the tremendous requirement of data traffic. LTE-A have adopted modern techniques such as Multiple-Input Multiple Output (MIMO)and Orthogonal Frequency Division Multiplexing OFDM to satisfy all the requirements and meet the tremendous growth of data. LTE-A with MIMO system schemebased on transmission modeClose Loop Spatial Multiplexing (CLSM).CLSM transmission modes used for doubling the bit stream and consequently increased the data rate with Adaptive modulation schemes. In this paper, The performance metrics considered are throughput. These are used to evaluate the performance of LTE-A in (AWGN) channel and Rayleigh Fading channel with detection schemes for CLSM with different band width (3, 5 and 10 MHz) and the following results has been obtained : at the same bandwidth (10 MHz) for 8x8 MIMO channel and AWGN at SNR (25dB) the maximum throughput equal(224.3 Mb/S) while in Rayleigh the throughput equal(203.8 Mb/S). A MATLAB simulation version R2013ahas been used to complete the analysis and comparison.