Simulation Study and Comparison Green Freeze Technology Utilizing with Theory of Different Adsorption Working Pairs of Solar Adsorption Refrigeration
Faiza
Mahdi Hadi
author
text
article
2012
eng
In this research a study of the theory of six different adsorption pairs to check and choose the best adsorption pair in terms of adsorption capacity and the effect of high and low temperature on it. It has been shown that the best adsorption pair at the temperature 25oC is the activated carbon fiber with methanol (ACF + CH3OH). Where the adsorption capacity is = 0.45 ACF x , followed by granules of activated carbon with methanol (AC + CH3OH) and adsorption capacity is = 0.3 AC x by more than half compared to a pair of activated carbon fibers. Then, four adsorption pairs have been selected for solar adsorption ice maker system and a couple for solar adsorption chiller system. The application of Excel has been used to solve governing equations and mathematical model of thermal balance simulation the largest amount of ice produced, the highest coefficient of performance for all pairs adsorption mentioned at the best operational temperature, it was found that the activated carbon fiber with methanol, the largest amount of ice produced 2.55kg and the highest coefficient of performance of 0.38 in the adsorption ice maker at operating temperature of generator is (110oC). The Adsorption chiller for a couple, silica gel with water, the best in terms of impact with the cooling effect and coefficient of performance of the highest at temperature range of (64 -110oC).
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
84
97
https://etj.uotechnology.edu.iq/article_25882_35d280aecd2430d7e052892c0187b100.pdf
dx.doi.org/10.30684/etj.30.3.15
Three Dimensional Simulation of Supersonic Flow over Missiles of Different Shapes
Jalal
M. Jalil
author
Hussain
H. Al-Kayiem
author
Ahmed
Kadhim Hussein
author
text
article
2012
eng
In this work, a three-dimensional primitive variable of supersonic flow over missiles was computed based on finite difference computational fluid dynamic methods. The problem was considered is to deal with external, inviscid, compressible supersonic- flow over three-dimensional missiles with and without canard. Euler equations were solved using time-marching MacCormack’s explicit technique. The flow conditions are taken at sea level and Mach number was tested up to 4.0. To deal with complex shape of missiles the so-called “body fitted coordinate system” was considered and the algebraic and elliptic methods were used to generate grids over missiles. The number of iterations and the number of mesh points depending on Mach number. The result indicate, that for the same Mach number, the increasing of mesh points, lead to increase of the number of iterations
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
325
343
https://etj.uotechnology.edu.iq/article_25868_d965973c5a6c592c2ba49c03a4514202.pdf
dx.doi.org/10.30684/etj.30.3.1
Removal of Iron (II) from Wastewater by Locally Prepared of Activated Carbon
Luma
H. Mohmoud
author
text
article
2012
eng
The use of low-cost activated carbon derived from reed, an agricultured waste material, has been investigated for the removed of Fe (II) from wastewater, using batch method. The influences of the weight of adsorbent (0.2-2) g, pH of solution (1-9) and initial Fe(II) concentration (10-80) mg/l have been studied. The suitability of the activated carbon used was tested by fitting the adsorption data with Langmuir and Freundlich isotherms. The study showed that the adsorption data obtained are obey the Freundlich isotherm fitting.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
344
353
https://etj.uotechnology.edu.iq/article_25869_0b94560d003d155e326d28f73d6e2c93.pdf
dx.doi.org/10.30684/etj.30.3.2
Study of Some Physical Behavior for Polycarbonate In Two Different Solvents at Room Temperature
Khalid
Mershed E
author
Raouf
Mahmood Raouf
author
Harith
Hasoon Jasim
author
text
article
2012
eng
The goal of this research was to study some Rheological and optical properties of poly carbonate in (chloroform and toluene) with different concentrations to know the physical behavior of this polymer in two solvents at room temperature.It was determined that the value of polymer solution in these two solvents with different concentrations and the optical absorption, average viscosity molecular weight Effective molecular radius. The results have shown that the values of density, (shear, relative, specific, reduced, original) viscosities, Effective molecular radius and average viscosity molecular weight, increase with poly carbonate concentration in two solvents.The results also showed that prepared concentrations density was significantly influenced by the density of solvents used; this influence was not in the same magnitude for the rest of measurements and calculations. This may be due to the dynamic behavior of the polymer in a solvent.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
354
363
https://etj.uotechnology.edu.iq/article_25870_0b2c8b05636bd85bef23669bba752260.pdf
dx.doi.org/10.30684/etj.30.3.3
A Fuzzy Interface System to Predict Ultimate Strength of Circular Concrete Filled Steel Tubular Columns
Kadhim
Zuboon Nasser
author
text
article
2012
eng
In this study, a model for predicting the ultimate strength of circular concrete filled steel tubular columns (CCFST) under axial loads has been developed using fuzzy inference system (FIS). The available experimental results for (129) specimens obtained from open literature were used to build the proposed model. The predicted strengths obtained from the proposed FIS model were compared with the experimental values and with unfactored design strengths predicted using the design procedure specified in the AISC 2005 and Eurocode 4 for CCFST columns. Results showed that the predicted values by the proposed FIS model were very close to the experimental values and were more accurate than the AISC 2005 and Eurocode 4 values. As a result, FIS provided an efficient alternative method in predicting the ultimate strength of CCFST columns.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
364
377
https://etj.uotechnology.edu.iq/article_25871_2d90bd18d350360ef6df6d69fa9a290a.pdf
dx.doi.org/10.30684/etj.30.3.4
Excitation Control of Synchronous Generator Via Neural Network Based Controllers
Ekhlas
M. Thajeel
author
text
article
2012
eng
Modern power systems are complex and non-linear and their operating can vary over a wide range. This paper presents a linear mathematical model of the synchronous generator to control the excitation system based on Neural Network to simulate an Automatic Voltage Regulator. The voltage regulator is used to modify terminal voltage for the purpose of tracking a reference voltage and comparative with PID controller. ANN (NARMA-L2) system is proposed as an effective controller model to achieve the desired enhancement. This model after training can be called as (Identifier).The proposed technique is evaluated on a single machine infinite bus under different operating conditions (no-load and full load condition) by using MATLAB simulink software.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
378
397
https://etj.uotechnology.edu.iq/article_25872_7175ff2ce4d9b48990e947a697fa9388.pdf
dx.doi.org/10.30684/etj.30.3.5
Experimental and Numeriacal Study of Moisture Moviment Inside an Air Conditioned Space
Wahid
S. Mohammad
author
Omar
M. Mohamme
author
text
article
2012
eng
This research is concerned with a computational study to simulate a turbulent three –dimensional buoyancy recirculation flow in an air-conditioned space. The study includes the simulation of heat and moisture generated from an internal source inside the space. An experimental facility to study temperature and moisture distribution in an airconditioned space has also been designed, constructed and tested in a laboratory scale. A numerical procedure was carried out to solve the elliptic partial differential equations that govern the flow, heat and mass transfer in a finite –volume form. The finite -volume approach was applied to solve these equations using the upwind –differencing scheme. The SIMPLE iterative procedure [1] for solving the algebraic equations is employed in the present study. The proposed method is the line by line technique uses the Tri- Diagonal Matrix Algorithm (TDMA) as its basic unit. A modified version of a threedimensional elliptic computer code was used to simulate heat and moisture transfer generated from the internal source inside the space. A study of the flow, heat and mass transfer in air-conditioned space are used as test cases to justify the performance of the computational procedure. The temperature and moisture distribution were compared with predictions of previous researchers. The data from the experimental model was also used to verify the computational procedure predictions.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
398
415
https://etj.uotechnology.edu.iq/article_25873_658798173958e408c522b8bafc664adf.pdf
dx.doi.org/10.30684/etj.30.3.6
Influence of Substrate Temperature on Structure and Optical Properties of CdO Thin Films Prepared By Pulsed Laser Deposition
Muhanad
Adel
author
Khaled
Z.Yahya
author
text
article
2012
eng
Nanocrystallites of cadmium oxide (CdO) thin films were deposited by pulsed laser deposition technique on glass substrates using Nd:YAG laser at 532nm wave length. X-ray diffraction (XRD) patterns confirmed the nanocrystalline cubic CdO phase formation. The intensity of XRD peaks increases with the increase in substrate temperature and better crystallinity takes place at higher temperature. The morphology of deposited films were characterized by scanning electron microscope (SEM) and atomic force microscope (AFM); with increasing substrate temperature, both the grain size and surface roughness increase .The grain size value (12,18,47 nm) and rms roughness values were 63.3, 98.8 and 138.4 nm for thin films deposited at 100 , 200 and 300ºC respectively. UV–Vis spectrophotometric measurement showed high transparency (nearly 88 % in the wavelength range 500–900 nm) of the CdO thin film with a direct allowed band gap value lying in the range 2.81–3.7eV
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
416
425
https://etj.uotechnology.edu.iq/article_25874_1c999053af18abf7dea14af49f12d6e9.pdf
dx.doi.org/10.30684/etj.30.3.7
Shock Wave Capturing Numerically in Two Dimensional Supersonic Wind Tunnel for Different Configuration
Ahmed
Fouad Mahdi
author
text
article
2012
eng
Numerical solutions of two dimensional Euler equations are obtained for transonic and supersonic flows. The shock capturing method is employed to solve compressible Euler equations by using MacCormack's time marching method that an explicit finite-difference technique. The test case chosen is that of a transonic and supersonic flow through a channel with a circular arc bump on the lower wall, half wedge and extended compression corner. Computational results accurately reproduced the flow field. In three cases, contour plots showing the important features of the flow-field are presented. The algorithm is tested for steady-state inviscid flows at different Mach numbers ranging from the transonic to the supersonic regime and the results are compared with the existing numerical solutions. The method incorporates bounded high resolution of discontinuities and is therefore well suited to all flow regimes ranging from transonic to supersonic.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
426
442
https://etj.uotechnology.edu.iq/article_25875_1269555fcdf5a42a478a50f3c20e28e5.pdf
dx.doi.org/10.30684/etj.30.3.8
Modification of Diffie–Hellman Key Exchange Algorithm for Zero Knowledge Proof
Mahmood
Khalel Ibrahim
author
text
article
2012
eng
Networks and entity groupings requires entity authentication while preserving the privacy of the entity being authenticated. Zero-Knowledge Proof (ZKP) plays an important role in authentication without revealing secret information. Diffie–Hellman (D-H) key exchange algorithm was developed to exchange secret keys through unprotected channels. This paper discusses zero-knowledge protocols and Diffie– Hellman algorithm and analyzes their vulnerability against known attacks. Also it presents a proposed protocol based on modification of Diffie–Hellman algorithm into an interactive zero-knowledge proof protocol. The proposed protocol is designed and developed to satisfy the zero-knowledge proof properties and resists the known attacks
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
443
453
https://etj.uotechnology.edu.iq/article_25876_f6bc48e36358df653f5ae584293d1fc8.pdf
dx.doi.org/10.30684/etj.30.3.9
Fuzzy-Swarm Controller for Automatic Voltage Regulator of Synchronous Generator
Abdulrahim
Thiab Humod
author
Wisam
Najm Al-Din Abed
author
text
article
2012
eng
The main objective of this work is to propose Artificial Intelligence (AI) controller to enhance the performance of Automatic Voltage Regulator (AVR) of a Synchronous Generator (SG) during different loading conditions. The proposed mathematical model of the SG with saturation nonlinearities is connected to different loads in two ways. The first each load is connected individually and the second the SG loads change during the operation to ensure the robustness of controller for wide load variations. Two types of controllers are used. The first controller is the Proportional-Integral (PI) based on Particle Swarm Optimization (PSO) technique to obtain optimal gains. The second controller is Fuzzy PD+I with gains and Membership Functions (MFs) tuned by PSO technique. The results show the improvement of PI-PSO performance on conventional PI controller; also show the improvement in the performance of Fuzzy PD+I using PSO technique on PI-PSO. The simulation of SG is performed using MATLAB program version 7.10.0.499 (R2010a).
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
454
473
https://etj.uotechnology.edu.iq/article_25877_242237e9989ae043c79b5d185577e597.pdf
dx.doi.org/10.30684/etj.30.3.10
LDPC Error Floor Improvement
Aseel
Hameed Majeed
author
text
article
2012
eng
The error-correcting performance of low-density parity check (LDPC) codes, when decoded using practical iterative decoding algorithms, is known to be close to Shannon limits. In this paper we study the LDPC codes performance when varying code rate, constellation level and the maximum number of iteration, this paper shows better coding gain can be obtained at the cost of higher complexity or higher bit rate. For some cases, due to their inability to reach very low bit error rates (e.g., 10− 12) at low signal-to-noise ratios (SNRs), a consequence the error rate floor phenomenon associated with iterative LDPC decoders is produced. This paper demonstrates that the concatenation system used LDPC as an inner code and the Bose, Chaudhuri, and Hocquenghem codes (BCH) as an outer code can successfully lower the floor. Connecting BCH codes lower the LDPC BER floor by a factor( from 32 to 22) at about SNR (from -1dB to 1.8 dB) with the same overall cod rate(i.e without any reduction in the bandwith efficiency) and restricted few number of iteration ( only 5 iterations).
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
474
488
https://etj.uotechnology.edu.iq/article_25878_327f9e05fb94f733a84490bf6c28a0ee.pdf
dx.doi.org/10.30684/etj.30.3.11
Experimental Study on Boiler Scales Cleaning Using Hydrochloric and Citric Acids
Dina
Raheem
author
Janet
Lazer
author
text
article
2012
eng
The effect of hydrochloric acid and citric acid was studied experimentally for boiler chemical cleaning to determine the dissolved scale by using carbon steel samples of water-side boiler tubes sections ,different concentrations of hydrochloric acid HCL and citric acid were used (2%,3%,4% and 5%) to calculate the weight loss of samples then determined the dissolved scale in gm/m2. The more efficient acid for the chemical cleaning, was found to be HCL acid at 5% concentration by using 0.3% rodin inhibitor at temp. 60 and time 30 minute to obtain 248 gm/m2 of dissolved scale while the citric acid at 5% concentration by using 0.3% hexamine inhibitor and temp.70 and time 240 minute to obtain 168 gm/m2 of scale dissolved.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
489
499
https://etj.uotechnology.edu.iq/article_25879_f4a034304aa48831a2e40eba5951874b.pdf
dx.doi.org/10.30684/etj.30.3.12
Evaluation of Crude Anthrax Protective Antigen as an Adjutant For Brucella Abortus Vaccine In Mice
Inam
Jasim Lafta
author
text
article
2012
eng
Anthrax crude protective antigen (PA) was used in this study as an adjutant with Brucella abortus S19 strain vaccine in a ratio of 1:1 to immunize mice in dose of 0.1 ml s/c in order to decrease side effects of S19 vaccine and also to enhance its immunogenicity. Three groups of mice were immunized with the mixture (composed of anthrax PA +S19, S19 alone, and sterile PBS solution as a control. They were compared concerning cellular and humeral immunity. The group treated with the mixture was the best regarding skin test, the difference of thickness was 1.51± 0.103 mm after 24 h and 1.14± 0.103 mm and 0.89± 0.100 mm after 48 and 72 h, respectively. As well as that group revealed the highest antibody titer, which reported 0.7153± 0.08 nm as compared with 0.3743± 0.06 nm in S19 group. These findings were verified by studying the histopathological changes.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
500
511
https://etj.uotechnology.edu.iq/article_25880_4702632b63ee24b9592fda6c45ff8b30.pdf
dx.doi.org/10.30684/etj.30.3.13
Construction of Railway Track Using Asphalt – Ballast Layer
Kawther
Y.H.AL-Soudany
author
text
article
2012
eng
The work presented in this paper focuses on new trends in the construction of rail track using asphalt ballast layer. Model tests were performed with ballast layer 150mm or 200mm. These thicknesses are the common range used in railway construction. Overlaying a sandy layer 400mm in thickness. This condition represents a case where rail networks pass through sandy zones. Two series of model tests were performed; the first on untreated ballast and the second where the ballast layer was incorporated with inter asphalt layers. A model footing 200mm wide and 400mm long was placed on the surface of the ballast layer and loaded monotonically or repeatedly up to failure. These dimensions were selected representing the plain strain condition which exists in real rail networks. The layers treated with asphalt demonstrated substantial improvement in the load carrying capacity over the untreated layers.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
30
v.
3
no.
2012
512
528
https://etj.uotechnology.edu.iq/article_25881_196359bd7c29a3e77213000aa831ae63.pdf
dx.doi.org/10.30684/etj.30.3.14