2024-03-28T12:57:30Z
https://etj.uotechnology.edu.iq/?_action=export&rf=summon&issue=1475
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Study of the nitriding process for samples coated with chromium by the deposition method
In this paper nitriding is performed on (Nitralloy135) alloyed steel which iscoated with chromium before heat treatment. Tests and inspections werepreformed like coated layer depth and hardness .The result show thatnitriding layer depth increases with nitriding time. Max. Layer depth is(0.45) mm with nitriding time (90) min. , when chromium is added to thealloy the nitriding depth layer increased with time decrease, and also inmicro structure test shows fine and uniform structure and stable steelphases.As for mechanical properties hardness was (1000HV) at (550°C), Also othermechanical properties (Tensile Stress, Yield Point, Elongation) as shown inproperties table ,So we have a hard tough sample with good properties asthe objective of this paper.
2008
02
28
37
48
https://etj.uotechnology.edu.iq/article_26085_ac030ffe26740376b3c581b4b5772535.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Influence of Locally Produced Waterproofing Admixture (Sternson 300) on Concrete Absorption and Strength
In this work, the influence of waterproofing admixture of stearate type on thewater reduction of concrete mix (1:2:4) for a given workability, (50+5)mm slump wasinvestigated. Results indicated that this admixture has a little influence on the waterreduction of concrete. Therefore this admixture cannot be considered as a waterreducer since it does not conform with the requirements of type (A) admixture inaccordance with (ASTM-C494-98 Type A)[1].The same influence on the compressive strength of concrete (fcu) at various ages(7,28,60 and 90) days was studied. Results showed that the use of this admixture atrecommended dose specified by the manufacturer has no significant effect on thecompressive strength of concrete. On the other hand, overdoses of this admixture leadto a considerable reduction in the compressive strength.The efficiency of this admixture at different doses in reducing the total waterabsorption of concrete and the absorption of water by the capillary action was alsoexamined. Results revealed that this admixture is not effective in reducing the waterabsorption with all doses used in this work and at different ages compared withreference mix without admixture.
2008
02
28
49
61
https://etj.uotechnology.edu.iq/article_26086_02c57de063b06c926e8c4bb4eadf1607.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
A Study on Wear and Erosion-Corrosion Resistance of Two Typs of Cast Irons.
Sami
A.Ajeel
Safaa
Mohammed Hasoni
The wear and erosion-corrosion resistance of gray and ductile cast ironswere studied for their important in most applications. The wear tests were carriedout using a pin-on-disc machine by applying different loads (10,20 and 30 N). Thewear rate was measured using weighting loss method.Erosion-corrosion rate measurements for both types of cast iron in(0.01%,0.58% and3.5%) NaCl solutions using a rotating disc of 450 rpm indicatethat erosion-corrosion resistance of ductile iron is better than that of gray cast iron.Microstructure observations after erosion-corrosion indicate that it plays arole in erosion-corrosion ; the predominant ductile matrix on the microstructure ofductile iron is at lower erosion-corrosion rate than that of gray cast iron .Localized attack usually has bright surfaces free from corrosion product. Pits areoften observed on the line flow direction on these materials. These pits have acharacteristic horse shoes shape for both types of cast irons. Optical microscopeexamination for the specimens indicates the presence of white and dark areaswhich refer to graphitization and pitting corrosion respectively. The wear rate isinfluenced by the form of phases therefore the flake graphite form in gray actsmore like a lubricant film between two contact surfaces than spheriodalgraphite. Brinell hardness measurements for both materials show that gray iron hashigher hardness than ductile iron so that wear tests at different loads (10, 20 and 30N) for both materials indicate that gray iron has high wear resistance than ductileiron and the wear rate increases sharply after (20N) for ductile iron. These resultsare related to high hardness and graphite phase form on the microstructure of grayiron.
2008
02
28
111
123
https://etj.uotechnology.edu.iq/article_26087_acfcf150b0986b7711e352a0c57f5561.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Vanadium Oxide Recovery from Spent Catalysts by ChemicaL Leaching
Falak
O.Abas
The Vanadium content of the catalyst can be reclaimed for further use. Theaim of present work is to recover Vanadium pentoxide (V2O5) from spent catalystwhich previously used by a local detergent factory using chemical treatment.This type of treatment consist of chemical solution of sodium hydroxide(NaOH 10–50 %) which is reacted with Vanadium in the spent catalyst to getsodium vanadiate at temperature(80 ± 5Cº) for (2-10) hrs to get pure Vanadiumpentoxide .Different extractive conditions were carried out for the same manufacturingsystem above as chemical alkali solution of NaOH with in the range (10-50 wt.%),time of chemical treatment with in the range (2-8 hrs) ,and mixing velocity forreaction solution with in the range (75-200 cycle/min) ,then a prepared productswill be optimized by the use of adsorption technique of vanadium on the surface ofactive carbon particles (2 mm mesh size) ,where 45 gm of active carbon wereapplied on packing column of 3 cm diameter and 300 cm long , then graph thisresults in order to optimize the extractive condition above and the optimizationresults are:Pure vanadium pentoxide (85%,3.60 gm ) from spent catalysts result atoptimum conditions of 20 wt.% of NaOH alkali solution ,8 hrs time of mixingreactants ,and 95 cycle/min mixing velocity (medium velocity to give homogeneityof reaction) .
2008
02
28
124
138
https://etj.uotechnology.edu.iq/article_26088_c925d407151ed7e7ed97ba55502bfe19.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
The Influence Of Bonding Mode and Wire Setting On The Stresses Of Metal Matrix Composite Reinforced with Continuous wire
Basim.
Mohammed Fadhel
This paper deals with the influence of bonding mode and the setting of thereinforcement between matrix and reinforcement for metal matrix composite on theinduced stresse and also on the value of the reinforcing A charpy specimen withnotch was used as a specimen test for comparison . Analytical model was builtvia ANSYS 8.1 software with a nonlinear solution based on the elastic –plasticbehavior for both phases (matrix and reinforcement).Five miscellaneous cases forbonding mode and the setting of the reinforcement (wire with 1 mm diameter)were used .The results exhibit the eloquent perfect bonding on the value ofreinforcing and also the setting (semi-circle) of the reinforcement in the matrixwhich gave the best reinforcing.
Metal matrix composites
fiber
ANSYS
2008
02
28
139
145
https://etj.uotechnology.edu.iq/article_26089_3388bd1225a6a5e15b30a3307bebc68f.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Effect of Coarse Aggregate Characteristics on Drying Shrinkage of Concrete
Tareq
Salih Al-Attar
Concrete is a composite material, consisting, mainly, of three phases: coarseaggregate, cement mortar, and the interface zone between them. The characteristicsof the interface zone largely govern the bond between cement paste or mortar andaggregate. The restraining effect of aggregate to drying shrinkage strain dependsmuch on the bond between aggregate and cement paste.In this paper, it is aimed to investigate the effect of coarse aggregatecharacteristics, that affect bond strength, such as; type, shape, surface texture, andmoisture content, on drying shrinkage. Four types of coarse aggregate were used.Three of them were normal-weight, while the fourth was a light-weight one. Eachtype of coarse aggregate was used in two moisture conditions, dry and saturated.The testing program extended to 150-days age and comprised; length change,modulus of elasticity, compressive and splitting tensile strength of concrete.It is concluded that using saturated coarse aggregate always yields highershrinkage strain than dry aggregate. The percentage increase seems to be affectedby the aggregate water absorption. At early ages, After 28 days, there is largedifferences in relative shrinkage for different mixes. Later than 28 days, thevariation in ratios settled to approximately fixed values
Coarse Aggregate
compressive strength
drying shrinkage
Interface zone
Limestone
Modulus of elasticity
Porcilinite
splitting tensile strength
Surface texture
2008
02
28
146
153
https://etj.uotechnology.edu.iq/article_26090_0baebf4c3ff44bbdb584c24d5b56d1f7.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Ductile and Gray Cast Irons Deterioration with Time in Various NaCl Salt Concentrations
Sami
A. Ajeel
Safaa
Mohommed Hasoni
Gray cast iron is used in wide engineering applications especially pipesand these pipes are exposed to failure in most cases so that ductile cast iron is usedinstead of it later.This project deals with the study of microstructure characteristics andchemical analysis for both materials in order to use them in the analysis of themicrostructure after the corrosion tests involving immersion, polarization indifferent sodium chloride concentrations (0.01%, 0.58% and 3.5% NaCl).Immersion results indicate that the corrosion resistance of both types ofcast irons is excellent and ductile iron is better than gray cast iron and thereduction in corrosion rates for both materials is related to barrier layer depositedon the surface which is more uniform on ductile iron surface.The electrochemical tests involve measurement of corrosion potential inopen circuit using the same solutions for both materials and potentiostatic test isused to measure cathodic and anodic polarization in the above solutions. The teststarted from cathodic region to the anodic region with sweep rate of 10 m V/min toobtain the general behavior and measure the polarization parameters for bothmaterials.The measured corrosion potentials of the open circuit in all solutions aremore noble values for gray iron than that for ductile iron. Corrosion potentials onpolarization measurements point out to the same indication but the ability tostart and form barrier layer in ductile is better than in gray iron.Microstructure observations after the electrochemical tests indicatethe presence of uniform layer on ductile surface and graphitization process isobtained on gray iron.
2008
02
28
154
168
https://etj.uotechnology.edu.iq/article_26091_cb702ac7f001f6df9804774755acaeff.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Stress Evaluation of Low Pressure Steam Turbine Rotor bBlade and Design of Reduced Stress Blade
Arkan
K. Husain Al-Taie
The low pressure steam turbine blade rows have a history of stress failure . They suffer fromtensile and bending stresses partly due to the centrifugal force as a result of high rotationalspeeds and partly due to high pressure, temperature and speed steam loading. The centrifugalforce is one of the problems that face the designers of turbine blades especially the long ones.The designer always aims at reducing these stresses. One way to do so is by the reduction of blademass. That is to make the blade of variable cross section stead in of straight. This paper presentsthe method of reducing cross section. Analysis of such blade is also done as applied to the (P 23-14A) steam blade.
Steam Turbines
design
stress
2008
02
28
169
179
https://etj.uotechnology.edu.iq/article_26092_dd74f9d60c1a63ecf5cfe2c177ecc42d.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Automated Electronic Circuit Design for Low Pass Filter Based on Genetic Algorithm
Hanan.
A. R. Akkar
Mohammed.
K. Abrahem
In this paper a proposed method to design electronic circuits by using software approach based ongenetic algorithms is presented. The method is implemented to design low pass filter with aminimal knowledge about the design (the response of the filter and cutoff frequency).Butterworth filter type is chosen because of its smooth response. This method providesimpressive results and the circuits obtained provide higher efficiency than the circuits whichmight be designed by the expert engineer. This method allows the topology, the componentvalues, and the number of the component of the circuit to be evolved by using genetic algorithms(GAs) without human interference. Therefore, the proposed method can be expandied to be usedwith any analog (passive or active) circuit by making a few changes in the program steps (i.e. bychanging the fitness function and improving the simulation of the circuits). MATLAB (Ver. 7)language is used in programming the genetic algorithm. The circuits created by geneticalgorithms are built using EWB program to make sure that the obtained results are true andaccurate.
2008
02
28
180
188
https://etj.uotechnology.edu.iq/article_26093_19482d18a40d3bdc074536febb19b759.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Numerical Simulation of Solidification Around Staggered Tube Arrangement With Convection – Dominated
Waheed
S . Mohammed
Zainab
H. Hassan
This work describes and analyses thermal storage system as a phase change problem whichinvolves a fluid flowing inside cooled tubes in a staggered arrangement installed in a rectangularduct surrounded by a phase - change material (water).The temperature of the fluid inside the tubes is below the freezing temperature of the PCM whichcauses ice formation around each tubes. The problem is modeled as, two- dimensional, timedependent and convection–dominated phenomena .A finite volume numerical approach isdeveloped and used to simulate the physical details of the problem .This approach is based on theenthalpy method which is traditionally used to track the motion of the liquid – solid front andobtain the temperature and velocity profiles in the liquid –phase. The study gives an instruction onthe presentation of ice – on – coil storage tank. Results of solidification experiments are used toassess and evaluate the performance.
Ice Formation
thermal storage
phase change
2008
02
28
189
201
https://etj.uotechnology.edu.iq/article_26094_36fe1adb8b89d1ca129e1ebb9cbe2f5c.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Modelling The Behaviour Of Sand Under Strain-Controlled Loading BY The Finite Element Method
Omar
al-Farouk S. al-Damluji
Mohammed
Yousif Fattah
Strain-controlled tests are conventional in soil mechanics laboratories. It isintended in this paper to simulate both triaxial and simple shear teststheoretically by using the finite element method. The solution of the nonlinearequations is obtained by several iterations. The Newton-Raphson withtangent stiffness method in which the stiffness matrices are tangents isadopted. The model used in this paper is the ALTERNAT model whichforms the major component of a double hardening model for the mechanicalbehaviour of sand under alternating loading.The finite element method is used in simulating the behaviour of rounduniform quartz sand under monotonic drained loading with constant meanstress and cyclic constant volume loading (undrained). The monotonic testwas conducted with constant mean stress, where the specimen wascompressed in one direction and extended in other directions while the meanstress (the average of the principal stresses) is kept constant and equal to 137kPa. It is noticed that the peak stress is occurring at very small strain(0.122). The stress-strain behaviour may be attributed to the particleroundness and grain size uniformity.In the cyclic tests, the specimen is sheared by cycling the shear strain whilethe volume was kept constant. By doing this, an undrained strain-controlledcyclic test similar to that typically done in many laboratories is numericallysimulated.It was found that the mean stress during shearing is higher than the initialconsolidation pressure. This implies that only negative pore pressures occurin the first two cycles. A careful study shows that there exists an effectivestress ratio line or zero-dilatancy line in both compression and extensionregions, beyond which the specimen dilates.
Strain
controlled
Sand
Finite elements
Cyclic
ALTERNAT Model
2008
02
28
202
227
https://etj.uotechnology.edu.iq/article_26095_c95068f831bcbfb44a83f4f56bb7ca5f.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Content-Based Authentication Using Digital Speech Data
Hanaa
M. Salman
A watermarking technique for speech content and speaker authenticationscheme, which is based on using abstracts of speech features relevant to semanticmeaning and combined with an ID for the speaker is proposed in this paper. The IDwhich, represents the watermark for the speaker, is embedded using spread spectrumtechnique. While the extracted abstracts of speech features are used to represents thewatermark for the speech, is embedded in the original speech file using secret key.The abstracts speech feature is implemented using B-spline curve interpolation. Thepaper provides a background knowledge for the concept of speaker watermarkingand content-fragile watermarking based on digital speech data. Then, the suggestedfeature based authentication scheme is develop and the results from the evaluationare presented. It shows that the suggested scheme is successful for combiningspeech and speaker watermark authentication.
speech content authentication
digital watermarking for speaker authentication
CONTENT
fragile watermarking authentication
spline interpolation
wavelet transform
2008
02
28
228
239
https://etj.uotechnology.edu.iq/article_26096_c9c209db3bf469b7077613679a037fb7.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Optimization of Production of Food Grade Gelatin from Bovine Hide Wastes
Mahmood
M. Barbooti
Shahrazad
R. Raouf
Firas
H. K. Al-Hamdan
The optimum conditions for the production of food grade gelatin from the tannerybovine hide wastes are established. The process involves cutting the hide wastes intosmall pieces (1-2 cm2), and washing them with water to remove the dirt. The washedpieces are placed in the liming tank containing 10% of lime in water with stirring forfive weeks. After washing with water to remove the lime, the collagen is neutralizedto pH 7 with hydrochloric acid. The extraction is carried out in four stages using hotwater. The gelatin extracts are filtered, subjected to deionization and concentratedwith vacuum evaporator up to 20-35 wt%. The gelatin is then dried by two types ofdryers (tray dryer and spray dryer).Box-Wilson method is adopted to obtain a relationship between the three variables(temperature, time and pH) and gelatin yield in the first stage of extraction and twovariables (temperature and time) and the gelatin yield in the other third stages ofextraction process. The experimental data were fitted to second order polynomialmodels for all stages.The most favorable operating conditions for the extraction of gelatin are: -The First Stage: Temperature = 64 oC , Time = 5 hr , pH = 7The Second Stage: Temperature = 74 oC , Time = 3.72 hr , pH = 7The third Stage: Temperature = 84 oC , Time = 3.69 hr , pH = 7The fourth Stage: Temperature = 98 oC , Time = 3.83 hr , pH = 7The overall yield of gelatin is 55%, under the previous condition. The quality ofgelatin was checked against food grade specification at the Nutrition ResearchInstitute of the Ministry of Health. The results are acceptable within the boundaries ofthe desired properties.
2008
02
28
240
253
https://etj.uotechnology.edu.iq/article_26097_ae7b3cfd736f302b280cf1a21ee04aa0.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Mechanical Properties of Composite Material Using Natural Rubber with Epoxy Resin
Hani
Aziz Ameen
In this paper the mechanical properties of three types of composite materials usingnatural rubber vulcanized, unvulcanized and reinforced rubber have beeninvestigated . The composite material using natural rubber and epoxy resin ismanufactured by three methods, first method is mixing the natural rubber withepoxy resin by special mixer without any additional materials, the second methodis to make a layer of rubber then coating it with a layer of epoxy resin and bondingusing the rolling process. The third one is use in the natural rubber as a matrixmaterial and using additional materials like carbon black in specific ratio and mixwith them the epoxy resin in five ratios ( 20%, 40%, 60%, 80%, and 100%) .The first and second methods failed because composite material produced wasinhomogeneous while the third method succeeded and the composite material washomogenous. Compression and hardness tests have been done on the resultingcomposite material of the third method and from the result it is found that thecomposite material has good properties and these properties improved byincreasing the ratio of epoxy resin to the natural rubber. Then the mechanicalproperties of three types of composite material using natural rubber vulcanized,unvulcanized and reinforced rubber have been investigated . Each type was coatedwith six percentages of epoxy resin (0% , 20% , 40%, 60%, 80%, and 100 %) . Thevalues of Young’s modulus, yield stress, tensile strength and yield strain whichwere calculated for each case and for all percentages of epoxy resin. It is concludedthat the properties of the new composite material using natural rubber ismuchbetter than the properties of the pure natural rubber and the increasing in thepercentage of epoxy resin in vulcanized rubber leads to a decrease in Young’smodulus and increasing percentage of epoxy resin in unvulcanized rubber andreinforced rubber leads to an increase in Young modulus
KEYWORDS
natural rubber
Epoxy resin
Engineering materials
2008
02
28
254
264
https://etj.uotechnology.edu.iq/article_26098_dee51589639637b1bb0918c10baf44f0.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
2
Indirect Field Orientation Control of Induction Machine with Detuning Effect
Rami
A. Mahir
Ziad
M. Ahmed
Amjad
J. H
Field orientation control (FOC) methods of an induction machine achievedecoupled torque and flux dynamics leading to independent control of torque andflux as for separately excited DC motor, but they are sensitive to motor parametervariations. The has present work selects the indirect field orientation control(IFOC) as an effective method for eliminating the coupling effect. The resultsshow how well the drive performance has been improved by this control strategy.However, to which extent the control strategy can perform the decoupling relies onthe accuracy of the slip frequency calculation. Unfortunately, the slip frequencydepends on the rotor time constant that varies continuously according to theoperational conditions and, then, the coupling effect may again arise.This paper investigates the improvement in the performance of theinduction machine dynamics as the IFOC technique is utilized, also, itinvestigatesthe degradation in dynamic performance when the rotor resistance isdeviated from its nominal value.
Induction Machine
Indirect field orientation control
Modelling
2008
02
28
265
277
https://etj.uotechnology.edu.iq/article_26099_ac13ad49a4c55df85d4ecbc8b8339e49.pdf