This study presents a transient thermo-mechanical finite element framework for high-speed end milling of AISI 4340 steel. The model couples moving heat sources, rate- and temperature-dependent plasticity, and adaptive mesh refinement (AMR) triggered by temperature gradient, plastic strain rate, and contact pressure. It is integrated with a design of experiments/response surface methodology using cutting speed (VC), feed per tooth (fZ), radial depth of cut/width of cut (ae), axial depth of cut (ap), and coolant mode. Responses include peak interface temperature per tooth (Tpeak), predicted surface residual stress (?_xx^"surf" ), and depth of compressive residual stress layer (dcomp). Experiments provide X-ray diffraction-based surface/depth profiles and arithmetic mean surface roughness (Ra). AMR is applied in this study to minimize the cut compute cost by 41-52% and error by 35-45%. Across 12 validation cuts, root mean square errors were 24 °C of Tpeak, 33 MPa of ?_xx^"surf" , 0.07 µm of Ra, and 22 MPa of dcomp. The response surface methodology and analysis of variance identified VC as the main driver of thermal load, while fZ, ae, and ap controlled the sign and depth of the residual field; coolant modified heat partition. Multi-objective desirability optimization with a material removal rate constraint yielded a balanced minimum quantity lubrication. Overall, exit-edge cooling and subsurface plasticity jointly set residual sign and magnitude; AMR is essential to resolve these gradients efficiently. The framework offers a reproducible route for residual stress-aware process planning in fatigue-critical AISI 4340 components while preserving throughput and is readily transferable to allied high-strength steels.
The Bi2Se3 compound was synthesis by fusing initial compounds consisting of
extra pure elements in stoichiometric ratio from elements compound, charged inside
quartz ampoule. The crystal growth of Bi2Se3 carried out using Brighaman technique
process from melting f (Bi+Se ) at temperature of 810 ºC for about 48 hrs. Single crystal
of Bi2Se3 has been grown in direction (211) after slow cooling on account of heat
gradient to zone furnaces at cooling rate (1-3) C/hr. The structure study of the compound
was determined by x-ray diffraction technique, which it has bismuthinite structure and
orthorhombic unit cell with lattice parameters of a=10.2678 Å, b=11.2392 Å and
c=5.1737 Å
Abstract
The multiple linear regression model of the important regression models used in the analysis for different fields of science Such as business, economics, medicine and social sciences high in data has undesirable effects on analysis results . The multicollinearity is a major problem in multiple linear regression. In its simplest state, it leads to the departure of the model parameter that is capable of its scientific properties, Also there is an important problem in regression analysis is the presence of high leverage points in the data have undesirable effects on the results of the analysis , In this research , we present some of
... Show MoreKnowing the distribution of the mechanical rock properties and the far field stresses for the field of interest is an important task for many applications concerning reservoir geomechanics, including wellbore instability analysis, hydraulic fracturing, sand production, reservoir compaction, and subsidence. A major challenge with determining the rock's mechanical properties is that they cannot be directly measured at the borehole. Furthermore, the recovered carbonate core samples for performing measurements are limited and they provide discrete data for specific depths.
The purpose of this study is to build 2D and 3D geomechanical models of the Khasib reservoir in the East Baghdad oil field/ Central area. TECHLOG.2015.3 softwa
... Show MoreA modern, rapid RP-HPLC-UV method was developed and validated in compliance with FDA and EMA guidelines for simultaneous quantification of 15 βlactam antibiotics) Ampicillin, Amoxicillin, cephalexin, cefotaxime, cefoxitin, cefamandole, cephalothin, piperacillin, penicillin, oxacillin, cloxacillin, nafcillin Carbenicillin, Mezlocillin and Dicloxacillin) in pharmaceutical formulations and pure forms. The method employs Column NEUCLEODUR C-18 (4.0 mm x 100 mm, 5µm particle size), at a temperature of thirty degrees Celsius, and the mobile phase was acetonitrile and KH2PO4 using gradient elution with a total separation time of 13 minutes, a flow rate of 1.3 ml/min, at = pH 4.5 for the buffer solution and the λ max was 220 nm. The met
... Show MoreIn this study, genetic algorithm was used to predict the reaction kinetics of Iraqi heavy naphtha catalytic reforming process located in Al-Doura refinery in Baghdad. One-dimensional steady state model was derived to describe commercial catalytic reforming unit consisting of four catalytic reforming reactors in series process.
The experimental information (Reformate composition and output temperature) for each four reactors collected at different operating conditions was used to predict the parameters of the proposed kinetic model. The kinetic model involving 24 components, 1 to 11 carbon atoms for paraffins and 6 to 11 carbon atom for naphthenes and aromatics with 71 reactions. The pre-exponential Arrhenius constants and a
... Show MoreStudy of the Mechanical and Electrical Properties of Modified Unsaturated Polyester Blends
The aim of the study was comparative between oxidative stress in diabetes mellitus using the measurement of some biophysical and biochemical parameters on two groups of diabetic patients, were conducted in the Al-Yarmuk Teaching Hospital,30 patients insulin dependent diabetes mellitus (IDDM) or type 1 ,their ages ranged between (15-45) and30 patients non- insulin dependent diabetes mellitus (NIDDM) or type 2,their ages ranged between (42-65).This study has been compared with 30 healthy subjects. The present study was demonstrated to evaluate the alteration in oxidative stress as measured by plasma and red blood cells Malondialdehyde (MDA) andchanges in antioxidant mechanism as measured by plasma and red blood cells Glutathione (GSH)
... Show MoreIt is becoming a public health issue to predict which expectant women will develop gestational diabetes mellitus (GDM). The goal of this case control research is to investigate the role of maternal oxidative stress levels in the first, second, and third trimesters, as well as other factors, in the development of gestational diabetes mellitus (GDM). Methods Between October and December 2021, 142 women participated in this research. The 101 GDM patients were split into three groups based on their gestation (T1, T2, and T3), and 41 healthy pregnant women were chosen as the comparison group. TAS and TOS levels of oxidative stress and XO were calculated using a Spectrophotometer for colorimetric techniques; fasting and random sugar levels, as
... Show MoreTo investigate the relationship between increased lipid peroxidation, and the lowering of both plasma total proteins and albumin in lead-exposed workers, and the effectiveness of antioxidants (vit. C and E) in modulating oxidative stress in those workers.
Thirty male and females workers employed in the Iraqi storage battery (age range 20-40 years) were participating in this study. Additionally, 11 healthy subjects were served as healthy controls, with the same age range compared to workers group, to avoid the effects of age variations on the studied parameters. Blood lead levels, erythrocytes and plasma MDA, erythrocytes and plasma GSH, total protein and albumin levels in healthy controls and lead-exposed workers pre- and post-tr
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