Engineering and Technology Journal

Improving Oxidation Resistance of Stainless Steel (AISI 316L) by Pack Cementation

Ali Moosa Ahmad; Khedeir Abbas Muna; Mohammed Rajab

Volume 25, Issue 7 , September 2007, , Page 918-939

https://doi.org/10.30684/etj.25.7.9

Abstract

The cyclic oxidation resistance of austenitic stainless steel (AISI 316L) can be improved by enriching the surface composition in Al and Si using pack cementation process. In this work, ... Read More ... The cyclic oxidation resistance of austenitic stainless steel (AISI 316L) can be improved by enriching the surface composition in Al and Si using pack cementation process. In this work, stainless steel is coated with two different types of coatings, the first one is Si-modified aluminide coating and the second is the Ce-doped silicon modified aluminide coating. Aluminum, silicon with and without cerium were simultaneously deposited by diffusion into St.St.316L substrate by the pack-cementation process, using a pack mixture containing (18%A1, 7%Si, 2%NH4C1 and 73%Al2O3) and 0.5% Ce (wt %) when required. Microstructure and chemical composition of the coated specimens were analyzed using electron microscopy (SEM) with energy dispersive spectroscopy (EDS). X-Ray diffraction (XRD) was used to identify phase formed in the surface layer of as-coated specimens. The coating time was changed, and it was found that diffusion coating time of 3h at 970C° produces coating thickness of 160-180μm and consist mainly of FeAl and (Cr4Si4Al13) phases. Also, the surface morphology for the coated samples after 3h coating time at 970C° are dense, smooth and homogeneous. Cyclic oxidation tests were conducted on the uncoated St.St.316L , Si-modified aluminide coating and on Ce-doped silicon modified aluminide coating at a temperature range between (700-900)C° in (air and H2O) for 120h at 10 h cycle. The oxidation kinetics for uncoated St.St.316L in air environment are found to be linear, while the oxidation kinetics at water vapor environment are found to be nearly parabolic. The linear rate constant (KL) and the parabolic rate constant (Kp) values obtained at 800C° in air and water vapor are –2.77*10-7(mg/cm2)/s and 2.18*10-5(mg2/cm4)/s respectively. The phases present on the cyclic oxidation of uncoated St.St.316L surface under most test conditions as revealed by XRD analysis are chromium (III) oxide, NiFe2O4, NiCr2O4 and iron oxide. Oxide phases that were formed on coated systems during air and H2O oxidation exposure condition are FeAl2O4, Fe(Al,Cr)2O4 and Fe2O3. The oxidation kinetics for both coated systems in air and water vapor are found to be linear and parabolic respectively.

Effect of Window Over-Hang in Iraqi Building on Cooling Load

Farag Antwan Nazar

Volume 25, Issue 7 , September 2007, , Page 940-949

https://doi.org/10.30684/etj.25.7.10

Abstract

A study is done on an Iraqi building to estimate and show how the use ofover hang reduces the cooling load. The study shows how the effectiveness ofover hang is affected by the orientation ... Read More ...

The Effect of Electrode Geometry and Pre-heating Treatment on Resistance Spot Welding Strength

Lana I. Hassan; Hameed D. Lafta

Volume 41, Issue 7 , July 2023, , Page 954-962

https://doi.org/10.30684/etj.2023.138070.1371

Abstract

Resistance spot welding (RSW) is one of the most significant and common metal joining methods used in industries. The present paper discusses the comparative performance of resistance ... Read More ...

Principle of Steganography Tool BCS (Bilevel Compression by Using Steganography)

Muzhir Sh. Al-Ani

Volume 24, Issue 8 , August 2005, , Page 955-960

https://doi.org/10.30684/etj.24.8A.5

Abstract

In this paper we make a new approach of compression used as a tool of steganography instead of make it as obstacle (BCS). The outline of BCS compression used two steps level 1 and level ... Read More ...

Speaker Recognition System Using Celluar Automata

Aladdin J. Abdulwahid; Ahmed A. Al-Attab

Volume 24, Issue 8 , August 2005, , Page 961-984

https://doi.org/10.30684/etj.24.8A.6

Abstract

Speaker recognition and voice recognition are subfields of speech processing by computer. They work on the principle that there are features of speech that can be used to discriminate ... Read More ...

The Effect of Vibrating Inner Cylinder on Natural Convective Heat Transfer in Concentric and Eccentric Horizontal Cylindrical Annuli

Baydaa K. Khudhair; Adel M. Saleh; Ali L. Ekaid

Volume 41, Issue 7 , July 2023, , Page 963-978

https://doi.org/10.30684/etj.2023.137848.1362

Abstract

In this study, natural heat convection caused by centric and vertically eccentric long horizontal cylinders under the influence of vibration is experimentally investigated. The internal ... Read More ... In this study, natural heat convection caused by centric and vertically eccentric long horizontal cylinders under the influence of vibration is experimentally investigated. The internal wall of the annulus is heated and kept at a constant heat flux, while the outside wall is cooled and maintained at a constant temperature. The vibration frequency impacts the annular convection heat transfer process and the effects of the Rayleigh number, heat flow, and eccentricity. This work employed a moderate, laminar-ranging Rayleigh number from (5×104 to 6.48×106), while the eccentricity range is varied from (-0.667, 0, and+0.667). The investigation is carried out at five different frequencies (0, 2, 5, 10, 15, and 20 Hz); therefore, it was decided to compare the case under the same circumstances in both the absence and presence of vibration. The present results' verification worked exceptionally well in concordance with previous studies. When heat fluxes are considered, the study demonstrates that the temperature difference along the gap (radial difference) between the two cylinders significantly decreases for negative as opposed to positive eccentricities for each Rayleigh number. For different eccentricities, it was discovered that the temperature difference decreased as the Rayleigh number increased. Along with these reductions, the temperature difference was promoted as the vibration frequency increased, which is significant at (20 Hz) within the range considered for controlling parameters. It was also observed that the decrease in temperature difference is higher for the negative eccentric position than for the centric and positive positions. At vertical positive eccentricity at a low Rayleigh number, the gain in vibrational average Nusselt number caused by applying vibration had a minimum value of 22.50601475%, While at the higher value of the Rayleigh number, the maximum increase in negative vertical eccentricity was 86.66933125%. However, the gain in the average Nusselt number depends on the position of the heated inner cylinder, the Rayleigh number, and the vibrational frequency.

Performance Evaluation of PV Panel Powered Dual Thermoelectric Air Conditioning System

Mustafa M. Salman; Mahmoud M. Mahdi; Majida K. Ahmed

Volume 41, Issue 7 , July 2023, , Page 979-990

https://doi.org/10.30684/etj.2023.138058.1370

Abstract

Thermoelectric air condition system (TEACs) powered by solar photovoltaics is useful for thermal comfort applications, especially when there is a direct energy source like sunlight. ... Read More ...

Numerical Investigation of Gas Turbine Combustion Chamber Flows

Waheed S. Mohammed; Shakair H. Aljanabe; Mokdad H. Rahman

Volume 24, Issue 8 , August 2005, , Page 985-998

https://doi.org/10.30684/etj.24.8A.7

Abstract

The paper present mathematical model for two-dimensional axi-symmetric, swirling recirculating, elliptic., turbulent, and reacting Now inside annular combustor. The present model is ... Read More ...

Exploring the effects of a new lifter design and ball mill speed on grinding performance and particle behaviour: A comparative analysis

Ali Safa; Sahraoui Aissat

Volume 41, Issue 7 , July 2023, , Page 991-1000

https://doi.org/10.30684/etj.2023.138456.1394

Abstract

Ball mills are the leading grinding equipment in the mineral processing industry. Balls are the primary component in the grinding of materials. Lifters lift these balls to the shoulder ... Read More ...

Calculation of The Electrons Distribution Function For Mercury - Argon Mixture

Ibrahim G. Faiadh; F. L. Rasheed; Hamid B. Mahood

Volume 24, Issue 8 , August 2005, , Page 999-1012

https://doi.org/10.30684/etj.24.8A.8

Abstract

The electron energy distribution in mercury-argon mixture discharge calculated numerically from the Boltzmann equation. In this job The mixture parameters such as drift velocity, excitation ... Read More ...

Impact of Cooling Fluid Temperature on the Structural Integrity of Gas Turbine Stator Blades

Olumide Towoju

Volume 41, Issue 7 , July 2023, , Page 1001-1009

https://doi.org/10.30684/etj.2023.138881.1409

Abstract

The importance of gas turbine engines to the aviation industry cannot be overemphasized. Being a major part of aircrafts and jets, its reliability must be second to none. They are continuously ... Read More ...

Analytical Study of Free Vibration Characteristics For Sandwich Cylindrical Shell With Single Phase Metal Core

Ahmed Mouthanna; Sadeq H. Bakhy; Muhannad Al-Waily

Volume 41, Issue 7 , July 2023, , Page 1010-1025

https://doi.org/10.30684/etj.2023.139795.1441

Abstract

This paper presents an analytical investigation of the nonlinear vibration characteristics of a single-phase functionally graded cylindrical shell panel with various porous metal cores. ... Read More ...

Finite Element of Linear Viscoelastic Solids

Imad Ahined Hussain

Volume 24, Issue 8 , August 2005, , Page 1013-1024

https://doi.org/10.30684/etj.24.8A.9

Abstract

A linear thermoviscoelastic material model, whose basis is an incremental constitutive equation that takes complete strain and temperature histories into account, is derived in finite ... Read More ...

Large Amplitude Vibrations of Clamped - Free Beams Under Thermal Gradient

Ahmed A. Al-Rajihy

Volume 24, Issue 8 , August 2005, , Page 1025-1032

https://doi.org/10.30684/etj.24.8A.10

Abstract

The large amplitude vibrations of an elastic straight beam with clamped free ends which have been subjected to thermal gradient are studied assuming that the beam is undergoing inextensional ... Read More ...

Comparative Study of Induction Motor and Steam Turbine at Kebon Agung Sugar Factory Malang Indonesia

Roro Heni Hendaryati; Sudarman Sudarman; Damario Indra Baskoro; Nyoto Susilo; Cucut Hendra Pamungkas; Willy Satrio Nugroho; Yepy Komaril Sofi'i

Volume 41, Issue 7 , July 2023, , Page 1026-1033

https://doi.org/10.30684/etj.2023.139996.1449

Abstract

Induction motors and steam turbines are the main components in the sugar cane milling process. This study analyzes the efficiency of induction motors and steam turbines as mill drives ... Read More ...

Dynamic modal analysis and synthesis of RSCR spatial Mechanism

Muhsin J .Jweeg; Fahim Al-Himdani; Mazin Ismail

Volume 24, Issue 8 , August 2005, , Page 1033-1051

https://doi.org/10.30684/etj.24.8A.11

Abstract

In this work analysis and synthesis of RSCR (Revolute -Spherical- Cylindrical-Revolute) spatial mechanism is presented. This work is based on the Hartenberg-Denavit 4 x 4 matrix method ... Read More ...

New Method To Implement Low Cost and High Speed 2D QMF

Dhafer R. Zaghar; Ammar A. Hassan

Volume 24, Issue 8 , August 2005, , Page 1052-1059

https://doi.org/10.30684/etj.24.8A.12

Abstract

There are two methods of H/W (hardware) implement of the 2D (two dimension) QMF (quadrate mirror filter), first method is a very low cost and a low speed, that use one pair of FIR (finite ... Read More ...

Estimation of Normal Pressure at Tool-chip Interface Based on Finite Element Method(FEM)

Maan Aabid Tawfiq

Volume 24, Issue 8 , August 2005, , Page 1060-1075

https://doi.org/10.30684/etj.24.8A.13

Abstract

The main objective of this study is to investigate the effect of rake angle on normal pressure distribution at tool-chip interface region, in order to gain better understanding of the ... Read More ...

Corrosion Control of a Steel Pipeline in Aqueous Chloride Solutions by Using CP Technique

Wathik Issa Mahdi; Fahim F. Al-Himdani; Abdul-Wahab Hassan Khuder

Volume 24, Issue 8 , August 2005, , Page 1076-1096

https://doi.org/10.30684/etj.24.8A.14

Abstract

The aim of this work is to improve the corrosion resistance of the steel pipeline structures utilizing concrete coating by using the cathodic protection technique. It deals with the ... Read More ... The aim of this work is to improve the corrosion resistance of the steel pipeline structures utilizing concrete coating by using the cathodic protection technique. It deals with the matter of steel structures upon the survey periods, electrochemical dormant period because of the continuous cathodic preventation and the activation corrosion upon interruption period of this cathodic preventation and treatment this case of corrosion by using the cathodic protection technique. The initial free corrosion potential (Ecorr) upon intermittently intervals and corrosion rate measurement of the specimens by using full polarization curve (Tafel method) has been observed. The required level of protection potential is achieved by using potentiostatic controlled potential. The results indicate that the moisture progressive within each specimen has produced different potentials along the steelpipe. Greater polarization has been associated with the submerged part of the specimen where the concrete coating resistance is at minimum. Whereas the degree of polarization is directly proportional with the level of external voltage. The results clearly indicated that to achieve efficient design of a cathodic protection, the protected area should be divided into discrete electrochemical areas, these areas are depending on the electrical resistance and steel potential which prevent the over-protection in the low electrical resistance areas when applying the designing criteria on the high electrical resistance areas. Furthermore, the results indicate that the absolute value of protection potential does not adequately to describe the electrochemical changes undergone by the polarized coated steelpipe. The instant off potential value (Ear) does not provide quantitative informations about the state of corrosion. The mechanism of the polarization behavior of steelpipe structure in aqueous solution is a fundamental different because of the high resistance of concrete coating and the alkali environment in which becomes the dominance factor on the polarization trends. Also, the results indicated that the relationship between the steelpipe potential and flowing current in calculated the electrical

Performance Analysis of Underwater Optical Communication System in Turbulent Link

Murtadha M. Joudha; Jassim K. Hmood; Salah A. Adnan

Volume 41, Issue 8 , August 2023, , Page 1082-1090

https://doi.org/10.30684/etj.2023.138423.1393

Abstract

Underwater wireless optical communication (UWOC) systems have been identified as a suitable replacement technology with high data rates over relatively medium transmission ranges for ... Read More ...

Implementation of Hyperbolic Sine and Cosine Functions Based on FPGA using different Approaches

Rawasee k. yousif; Ivan A. Hashim; Bassam H. Abd

Volume 41, Issue 8 , August 2023, , Page 1091-1106

https://doi.org/10.30684/etj.2023.139756.1440

Abstract

This paper presents the implementations of the hyperbolic sine and cosine functions, which are essential in many digital systems. In the previous eras, these functions were only implemented ... Read More ...

Evaluation of Enamel Coatings General Corrosion in Sulphuric Acid Solution at Different Temperatures

Ibtihal Abdul Razak; Lamy a.M. Dawood

Volume 24, Issue 8 , August 2005, , Page 1097-1106

https://doi.org/10.30684/etj.24.8A.15

Abstract

The aim of this study is to evaluate the general corrosion resistance for different ground and cover enamel coated specimen in 20% (by volume) of sulphuric acid solution for 48 hrs. ... Read More ...

Speech Recognition Algorithm in a Noisy Environment Based on Power Normalized Cepstral Coefficient and Modified Weighted-KNN

Mohammed E. Safi; Eyad I. Abbas

Volume 41, Issue 8 , August 2023, , Page 1107-1117

https://doi.org/10.30684/etj.2023.140643.1469

Abstract

Speech recognition is widely used in robot control and automation. Nevertheless, the use of speech recognition in robots is limited due to its susceptibility to background noise. This ... Read More ...

Strength Analysis of Delta Wing Structure With Different Configuration

Muhsin J. Jweeg; Abbass Z. Salman; Naseer H. Farhood

Volume 24, Issue 8 , August 2005, , Page 1107-1127

https://doi.org/10.30684/etj.24.8A.16

Abstract

In this study, a theoretical analysis was used to investigate the wing aerodynamic analysis and the best structural configuration of a delta wing with a satisfaction for the design ... Read More ...

Investigation of Fault Analysis for Renewable Energy Microgrid

Afaneen A. Abbood; Hanan M. Habbi; Mohamed A. Zohdy

Volume 41, Issue 8 , August 2023, , Page 1118-1129

https://doi.org/10.30684/etj.2023.139498.1433

Abstract

This paper investigates the behavior of four bus grid-connected systems during different types of faults. The microgrid comprises a utility grid, a solar PV energy system, a diesel ... Read More ...