Preferred Language
Articles
/
alkej-344
The Effects of Long-Term Operation and High Temperature on Material Properties of Austenitic Stainless Steel Type 321H
...Show More Authors

Changes in mechanical properties of material as a result of service in different conditions can be provided by mechanical testing to assist the estimation of current internal situation of these materials, or the degree of deterioration may exist in furnaces serviced at high temperature and exceed their design life. Because of the rarity works on austenitic stainless steel material type AISI 321H, in this work, ultimate tensile strength, yield strength, elongation, hardness, and absorbed energy by impact are evaluated based on experimental data obtained from mechanical testing. Samples of tubes are extracted from furnace belong to hydrotreaterunit, also samples from un-used tube material are used to make comparisons between these properties. Tensile properties of stainless steel (AISI 321H) were decreased as temperature increases; the trend of properties decreasing for the samples of un-used tube material is the same for the ex-used material. The trend of stress-strain curve will not change due to elevated temperature exposure for long time of service, except the yield strength will be higher in this diagram. The yield strength increased under these conditions, but the ability of material  which is elongated will decrease. Hardness and absorbed energy increased by 11.28 and 14% respectively when the material is aged for long time under effect of high temperature accompanied with creep effect.

Keywords:  Hardness, Impact, Mechanical Properties, Stainless Steel 321H, Mechanical Properties, Tensile Strength, Tube Furnace.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Jan 01 2026
Journal Name
Aip Conference Proceedings
Preparation and study of the annealing temperature, optical and structural properties of ZnTe0.8Se0.2 thin films
...Show More Authors

View Publication Preview PDF
Scopus Crossref
Publication Date
Sun Apr 08 2018
Journal Name
Al-khwarizmi Engineering Journal
Physical and Morphological Properties of Hard- Soft Ferrite Functionally Graded Materials
...Show More Authors

  Functionally graded materials (FGMs), with ceramic –ceramic constituents are fabricated using powder technology techniques. In this work three different sets of FGMs samples were designed in to 3 layers, 5 layers and 7 layers. The ceramic constituents were represented by hard ferrite (Barium ferrite) and soft ferrite (lithium ferrite). All samples sintered at constant temperature at 1100oC for 2 hrs. and characterized by FESEM. Some physical properties were measured for fabricated FGMs include apparent density, bulk density, porosity, shrinkage and hardness. The results indicated that the density increase with the increase the number of layer. Lateral shrinkage is one of the important parameter f

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Mon May 11 2020
Journal Name
Baghdad Science Journal
On the Growth of Solutions of Second Order Linear Complex Differential Equations whose Coefficients Satisfy Certain Conditions
...Show More Authors

In this paper, we study the growth of solutions of the second order linear complex differential equations  insuring that any nontrivial solutions are of infinite order. It is assumed that the coefficients satisfy the extremal condition for Yang’s inequality and the extremal condition for Denjoy’s conjecture. The other condition is that one of the coefficients itself is a solution of the differential equation .

View Publication Preview PDF
Scopus Clarivate Crossref
Publication Date
Wed Nov 28 2018
Journal Name
Al-khwarizmi Engineering Journal
Effect of Using Combined Square Nozzle & winglet with Helical Tape on Thermal Characteristics in Tube Heat Exchanger
...Show More Authors

Influence of combined square nozzle with helical tape inserted in a constant heat flux tube on heat transfer enhancement for turbulent airflow for Reynolds number ranging from 7000 to 14500 were investigated experimentally. Three different pitch ratios for square nozzle (PR = 5.8, 7.7 and 11.6) according to three different numbers of square nozzle (N = 3, 4 and 5) and constant pitch ratios for helical tape were used. The results observed that the Nusselt number and friction factor for combination with winglets were found to be up to 33.8 % and 21.4 %, respectively higher than nozzle alone for pitch ratio PR=5.8. The maximum value of thermal performance for using combination with winglets was about 1.351 for pitch ratio= 5.8. Nusselt numb

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Jul 26 2026
Journal Name
Journal Of Baghdad College Of Dentistry
An in vitro evaluation of shear bond strength of chemical and light-cured bonding materials with stainless steel, ceramic, and sapphire brackets
...Show More Authors

View Publication
Publication Date
Sun Jul 26 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Effect of disinfectant agents on certain physical and mechanical properties of type IV dental stone
...Show More Authors

Background: Dental stone casts come into contact with impression materials and becomes susceptible to cross contamination from saliva and blood. This study was done to evaluate the physical and mechanical properties of dental stone type IV after treatments with various disinfecting agents and regimes (methods). Materials and Methods: Type IV dental stone and different types of disinfecting agents were used and divided into seven groups: G1: dental stone without disinfection (control group), G2: dental stone mixed with silver nitrate powder 0.5% , G3: dental stone mixed with silver nitrate powder 1%, G4: dental stone mixed with copper sulfate powder 0.5%, G5: dental stone mixed with copper sulfate powder 1% ,G6: dental stone immersed in prop

... Show More
View Publication Preview PDF
Publication Date
Sun Jul 26 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation the effect of nano-fillers (TiO2, AL2O3, SiO2) addition on glass transition temperature, E-Moudulus and coefficient of thermal expansion of acrylic denture base material
...Show More Authors

Background: The PMMA polymer denture base materials are low in thermal and strength properties. The aim of the study was to investigate the change in glass transition temperature, E-Moudulus and coefficient of thermal expansion of acrylic denture base material by addition of Al2O3, TiO2 and SiO2nano-fillers in 5% by weight. Materials and methods: The type of polymerization is free radical bulk polymerization. one hundred twenty (120) specimens were prepared , the specimens were divided into four groups according to the material had been added (one control and three for Al2O3, TiO2 and SiO2nanocomposite) each group was subdivided in to three groups according to the test had been done on it, the degree of transition (Tg) was measured by The d

... Show More
View Publication Preview PDF
Publication Date
Sun Oct 01 2023
Journal Name
Baghdad Science Journal
Estimation of Apelin Levels in Iraqi Patients with Type II Diabetic Peripheral Neuropathy
...Show More Authors

Diabetes mellitus type 2 (T2DM) is a chronic and progressive condition, which affects people all around the world. The risk of complications increases with age if the disease is not managed properly. Diabetic neuropathy is caused by excessive blood glucose and lipid levels, resulting in nerve damage. Apelin is a peptide hormone that is found in different human organs, including the central nervous system and adipose tissue. The aim of this study is to estimate Apelin levels in diabetes type 2 and Diabetic peripheral Neuropathy (DPN) Iraqi patients and show the extent of peripheral nerve damage. The current study included 120 participants: 40 patients with Diabetes Mellitus, 40 patients with Diabetic peripheral Neuropathy, and 40 healthy

... Show More
View Publication Preview PDF
Scopus (14)
Crossref (7)
Scopus Crossref
Publication Date
Fri Mar 30 2018
Journal Name
Journal Of Pure And Applied Microbiology
The Effect of Polyester Fibers Addition on Some Mechanical Properties of Room Temperature Vulcanized Maxillofacial Silicon Elastomers
...Show More Authors

View Publication
Scopus (1)
Crossref (1)
Scopus Crossref
Publication Date
Fri Mar 01 2019
Journal Name
Al-khwarizmi Engineering Journal
The Effect of Additives on The Performance of Hydrostatic Thrust Bearings
...Show More Authors

 

The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed.  Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness.

The theoretical results show an increase in load capacity by (8.3%) in the presence of solid graphite particles with concentration of (16%) by weight as compared with pure oil, with increasing shear stress.  .

In general the performance of hydrostatic thrust bearings improve for load carrying capacity, volume flow rate,

... Show More
View Publication Preview PDF