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A Predictive Modeling Based on Regression and Artificial Neural Network Analysis of Laser Transformation Hardening for Cylindrical Steel Workpieces

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Journal of Surface Engineered Materials and Advanced Technology 2016年第4期6卷 149-163页

作者： ahmed ghazi jerniti Abderazzak El Ouafi Noureddine Barka Mathematics Computer Science and Engineering Department University of Quebec at Rimouski Rimouski Canada

Laser surface hardening is a very promising hardening process for ferrous alloys where transformations occur during cooling after laser heating in the solid state. The characteristics of the hardened surface depend on the physicochemical properties of the material as well as the heating system parameters. To exploit the benefits presented by the laser hardening process, it is necessary to develop an integrated strategy to control the process parameters in order to produce desired hardened surface attributes without being forced to use the traditional and fastidious trial and error procedures. This study presents a comprehensive modelling approach for predicting the hardened surface physical and geometrical attributes. The laser surface transformation hardening of cylindrical AISI 4340 steel workpieces is modeled using the conventional regression equation method as well as artificial neural network method. The process parameters included in the study are laser power, beam scanning speed, and the workpiece rotational speed. The upper and the lower limits for each parameter are chosen considering the start of the transformation hardening and the maximum hardened zone without surface melting. The resulting models are able to predict the depths representing the maximum hardness zone, the hardness drop zone, and the overheated zone without martensite transformation. Because of its ability to model highly nonlinear problems, the ANN based model presents the best modelling results and can predict the hardness profile with good accuracy.

关键词： Heat Treatment Laser Surface Hardening Hardness Predictive Modeling Regression Analysis Artificial Neural Network Cylindrical Steel Workpieces AISI 4340 Steel Nd:Yag Laser System

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Single Track Laser Surface Hardening Model for AISI 4340 Steel Using the Finite Element Method

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Modeling and Numerical Simulation of Material Science 2016年第2期6卷 17-27页

作者： ahmed ghazi jerniti Abderazzak El Ouafi Noureddine Barka Computer Science and Engineering Department University of Quebec Rimouski Canada

Laser surface hardening becomes one of the most effective techniques used to enhance wear and fatigue resistance of mechanical parts. The characteristics of the hardened surface depend on the physicochemical properties of the material as well as the heating system parameters. To adequately exploit the benefits presented by the laser heating method, it is necessary to develop a comprehensive strategy to control the process parameters in order to produce desired hardened surface attributes without being forced to use the traditional and fastidious trial and error procedures. This study presents a comprehensive approach used to build a simplified model for predicting the hardness profile. A finite element method based prediction model for AISI 4340 steel is investigated. A circular shape with a Gaussian distribution is used for modeling the laser heat source. COMSOL MULTIPHYSICS software is used to solve the heat transfer equations, estimate the temperature distribution in the part and consequently predict the hardness profile. A commercial 3 kW Nd:Yag laser system is combined to a structured experimental design and confirmed statistical analysis tools for conducting the experimental calibration and validation of the model. The results reveal that the model can effectively lead to a consistent and accurate prediction of the hardness profile characteristics under variable hardening parameters and conditions. The results show great concordance between predicted and measured values for the dimensions of hardened and melted zones.

关键词： Heat Treatment Laser Surface Hardening AISI 4340 Nd:Yag Laser System Finite Element Method Hardness Profile Prediction

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Comparison of DSHA-based response spectrum with design response spectrum of building code of Pakistan(BCP-SP-2007)for a site in Muzaffargarh area,Pakistan

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Earthquake Science 2022年第4期35卷 280-292页

作者： Naseer ahmed Shahid ghazi Institute of Geology University of PunjabLahore 54000Pakistan Centre for Geographic Information System University of PunjabLahore 54000Pakistan

The building code of any country is considered to be a basic technical guidance document for the seismic design of ***,building codes are typically developed for the whole country,without considering site specific models that incorporate detailed site-specific ***,the adequacy of the design spectrum for building codes may sometimes be *** study the sufficiency of the building codes of Pakistan(BCP-SP-2007),a deterministic seismic hazard analysis(DSHA)based spectrum was developed for a site in the Muzaffargarh area,Pakistan,using an updated earthquake catalogue,seismic source model,and a next generation attenuation model(NGA-WEST-2).Further,an International Building Code(IBC-2000)spectrum was developed for the study area to compare the *** DSHA-based response spectrum resulted in a peak ground acceleration(PGA)value of 0.21 g for the Chaudwan *** evaluation of BCP-SP-2007 and IBC-2000 spectra provided a critical assessment for analyzing the associated margins.A comparison with the DSHA-based response spectrum showed that the BCP-SP-2007 design spectrum mostly overlapped with the DSHA spectrum unlike ***,special attention is needed for designing buildings in the study area when considering earthquake periods longer than 1 s,and the BCP-SP-2007 spectrum can be enhanced when considering a period range of 0.12-0.64 ***,BCP-SP-2007 is based on a probabilistic approach and its comparison with deterministic results showed the significance of both methods in terms of design.

关键词： deterministic seismic hazard analysis earthquakes probabilistic seismic hazard analysis building code response spectrum

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Can preoperative planning using IRIS™three-dimensional anatomical virtual models predict operative findings during robot-assisted partial nephrectomy?

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Asian Journal of Urology 2023年第4期10卷 431-439页

作者： ahmed ghazi Nitin Sharma ahmed Radwan Hani Rashid Thomas Osinski Thomas Frye William Tabayoyong Jonathan Bloom Jean Joseph University of Rochester Urology DepartmentRochesterNYUSA Ain Shams University Urology DepartmentCairoEgypt

Objective To evaluate the predictive validity of IRIS™(Intuitive Surgical®,Sunnyvale,CA,USA)as a planning tool for robot-assisted partial nephrectomy(RAPN)by assessing the degree of overlap with intraoperative *** Thirty-one patients scheduled for RAPN by four experienced urologists were enrolled in a prospective *** to surgery,urologists reviewed the IRIS™three-dimensional model on an iphone Operating System(iOS)app and completed a questionnaire outlining their surgical plan including surgical approach,and ischemia technique as well as confidence in executing this ***,questionnaires assessing the procedural approach,clinical utility,efficiency,and effectiveness of IRIS™were *** degree of overlap between the preoperative and intraoperative questionnaires and between the planned approach and actual execution of the procedure was *** were answered on a 5-point Likert scale and scores of 4 or greater were considered *** Mean age was 65.1 years with a mean tumor size of 27.7 mm(interquartile range 17.5-44.0 mm).Hilar tumors consisted of 32.3%;48.4%of patients had *** scores of *** preoperative questionnaires,the surgeons reported that in 67.7%cases they were confident that they can perform the procedure successfully,and on intraoperative questionnaires,the surgeons reported that in 96.8%cases IRIS™helped achieve good spatial sensation of the *** was a high degree of overlap between preoperative and intraoperative questionnaires for the surgical approach,interpreting anatomical details and clinical *** comparing plans for selective or off-clamp,the preoperative plan was executed in 90.0%of cases *** A high degree of overlap between the preoperative surgical approach and intraoperative RAPN execution was found using IRIS™.This is the first study to evaluate the predictive accuracy of IRIS™during RAPN by comparing preoperative pl

关键词： Renal cancer Patient-specific Three-dimensional virtual model Imaging Partial nephrectomy Robotics

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Depositional facies and reservoir characteristics of the Early Cretaceous Lower Goru Formation,Lower Indus Basin Pakistan:Integration of petrographic and gamma-ray log analysis

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Petroleum 2023年第3期9卷 331-341页

作者： Qamar UZ Zaman Dar Pu Renhai Shahid ghazi Shakeel Ahme Rana Imran Ali Mubashir Mehmood Department of Geology Northwest UniversityXi'an710069China Institute of Geology University of the PunjabLahore54000Pakistan Oil and Gas Development Company Limited Islamabad44000Pakistan Kuwait Foreign Petroleum Exploration Company(Kufpec) Islamabad44000Pakistan Department of Geology Abdul Wali Khan UniversityMardan23130Pakistan

The sand intervals of the Early Cretaceous Lower Goru Formation are a conventional reservoir,generally distributed in the Middle and Lower Indus Basin of *** formation is classified into two parts;the upper parts are predominantly composed of shale,siltstone,and thin layers of alternate shale and sandstone,while the lower parts are composed of sandstone with interlayering of shale and *** sandstone of the Lower Goru Formation has been further divided into A,B,C,and D sand intervals based on reservoir *** depositional facies and reservoir characteristics are essential for the evaluation of hydrocarbon exploration and *** paper aims to evaluate the depositional environment and reservoir characterization of the siliciclastic reservoir of the Early Cretaceous Lower Goru Formation by integrating the gamma-ray log patterns and petrographic analysis and scanning electron microscopic(SEM)*** characterization of the sand intervals and Gamma-ray log signatures were used for the interpretation of the depositional environment of the reservoir *** analysis reveals that the sandstone of the Lower Goru Formation is fine-to medium-grained,well-sorted,arkose or feldspathic *** intergranular macroporosity,secondary intragranular macropores,and Intercrystalline micropores were identified within the sandstone by the SEM *** diagenetic analysis suggests that the sandstone possesses high porosity,low permeability,and has undergone significant alterations such as compaction,quartz cementation,feldspar dissolution,and clay minerals *** electrofacies are interpreted based on gamma-ray log patterns including(1)funnel shape(FA);(2)bell shape(FB);(3)cylindrical shape(FC);(4)bow shape(FD);and(5)serrated shape(FE)*** interpreted facies results reveal shoreface environment for A-sand,Tidal flat for B-sand,mixed tidal flat for C sand,Tide dominated mixed fo

关键词： Depositional facies Early cretaceous Electrofacies Gamma-ray pattern Lower goru Petrographic analysis

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Simultaneous biportal endoscopic management of pineal region tumors in patients with obstructive hydrocephalus:technical notes

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Chinese Neurosurgical Journal 2023年第2期9卷 51-57页

作者： Sultan Al-Saiari Khalid Al Orabi Mohammad ghazi Abdoh Abdulaziz A.Basurrah Sultan Faez Albalawi ahmed A.Farag Neurosurgery Department King Abdullah Medical CityP.O 24246MakkahSaudi Arabia

Background The goal of this study is to show the feasibility and benefits of using the simultaneous biportal endoscopic procedure to treat pineal tumors in patients with obstructive *** We retrospectively reviewed three patients with pineal tumors and acute obstructive hydrocephalus who were treated in one session with a frameless stereotactic guided simultaneous biportal endoscopic third ventriculostomy and endoscopic tumor biopsy performed through two separate ports using one rigid *** In the three patients,ventriculostomy and endoscopic biopsies were *** was no death or morbidity throughout the 45-min *** of the patients’histological findings were *** was diagnosed in two patients who recieved postoperative radiotherapy,and the third patient diagnosed with a *** resonance imaging with flow-sensitive sequences was used to confirm ventriculostomy patency in all patients 6 months after the *** Biportal endoscopic approach enables better visual control of both ***,it allows the surgeon to safely pass the ventriculoscope via the foramen of monro,even if it is ***,during endoscopic tumor biopsy and third ventriculostomy,the intracranial pressure can be smoothly managed using the outlet tubes *** treatment may be an alternative to traditional uniportal endoscopic operations in certain patients.

关键词： Pineal tumors Germinoma Hydrocephalus Endoscopic third ventriculostomy Endoscopic biopsy

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Extended lymph node dissection for intermediate and high-risk prostate cancer： do we have all the evidence？

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Asian Journal of Andrology 2015年第2期17卷 335-335页

作者： ahmed ghazi Department of Urology University of Rochester Medical Center Rochester NY USA.

In the article ＂extended lymph node dissection in robot-assisted radical prostatectomy： lymph node yield and distribution of metastases＂ published on Asian Journal of Andrology, Kim et al.1 present their robot-assisted experience for an extended pelvic lymph node dissection （E-PLND） in the management of intermediate and high-risk prostate cancer patients. The reported lymph node yield and positivity is comparable to literature published in robot-assisted and open approaches for radical prostatectomy.2 Increasing reports of a decline in the incidence of lymph node dissection,3 have questioned the adequacy of an E-PLND performed through the robot-assisted approach.

关键词： ASSISTED RADICAL PROSTATECTOMY IMPACT LYMPHADENECTOMY SURVIVAL YIELD

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Beta-endorphin in serum and seminal plasma in infertile men

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Asian Journal of Andrology 2006年第6期8卷 709-712页

作者： Shawky El-Haggar Salah El-Ashmawy ahmed Attia Taymour Mostafa M.M.Farid Roaiah Ashraf Fayez Sherif ghazi Wael Zohdy Nagwa Roshdy Andrology Department Clinical Pathology Department Medical Biochemistry Department Faculty of MedicineCairo UniversityCairo 12311Egypt

Aim： To access beta-endorphin levels in serum as well as seminal plasma in different infertile male groups. Methods： Beta-endorphin was estimated in the serum and seminal plasma by enzyme-linked immunosorbent assay （ELISA） method in 80 infertile men equally divided into four groups： non-obstructive azoospermia （NOA）, obstructive azoospermia （OA）, congenital bilateral absent vas deferens （CBVAD） and asthenozoospermia. The results were compared to those of 20 normozoospermic proven fertile men. Results： There was a decrease in the mean levels of betaendorphin in the seminal plasma of all successive infertile groups （mean ± SD： NOA 51.30 ± 27.37, OA 51.88 ± 9.47, CBAVD 20.36 ± 13.39, asthenozoospermia 49.26 ± 12.49 pg/mL, respectively） compared to the normozoospermic fertile control （87.23 ± 29.55 pg/mL）. This relation was not present in mean serum level of beta-endorphin between four infertile groups （51.09 ± 14.71, 49.76 ± 12.4, 33.96 ± 7.2, 69.1 ± 16.57 pg/mL, respectively） and the fertile control group （49.26 ± 31.32 pg/mL）. The CBVAD group showed the lowest seminal plasma mean level of beta-endorphin. Testicular contribution of seminal beta-endorphin was estimated to be approximately 40%. Seminal beta-endorphin showed significant correlation with the sperm concentration （r = 0.699, P = 0.0188） and nonsignificant correlation with its serum level （r = 0.375, P = 0.185） or with the sperm motility percentage （r = 0.470, P = 0.899）. Conclusion： The estimation of beta-endorphin alone is not conclusive to evaluate male reproduction as there are many other opiates acting at the hypothalamic pituitary gonadal axis.

关键词： azoospermia beta-endorphin male infertility opioid peptides semen seminal plasma

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Seroprevalence of Toxoplasma gondii among AIDS Patients in Saudi Arabia

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World Journal of AIDS 2016年第3期6卷 81-86页

作者： Rana ghazi Zaini Khadiga ahmed Ismail Haytham Dahlawi Clinical Laboratory Department Faculty of Applied Medical Sciences Taif University Taif Saudi Arabia Faculty of Medicine Ain-Shams University Cairo Egypt

Background: Toxoplasma gondii (T. gondii) is an intracellular parasite mainly found in the central nervous system CNS, however, it can persist in multiple tissues in the body. Moreover, T. gondii is the commonest protozoans causing infections among individuals with acquired immunodeficiency syndrome (AIDS). Thus, the aim of this study was to investigate the frequency of T. gondii infection among AIDS patients in Makkah at Saudi Arabia. Methods: Fifty patients with AIDS proved to be positive by ULTRA HIV Ag-Ab Enzyme Immunoassay, and thirty healthy volunteers negative for AIDS by ULTRA HIV Ag-Ab Enzyme Immunoassay were subjected to determination of anti T. gondii immunoglobulin M (IgM) antibody seropositivity and anti T. gondii immunoglobulin G (IgG) antibody seropositivity using commercially available enzyme-linked immunosorbent assay kits. Results: The results showed that the seropositivity rate of anti T. gondii IgM antibodies among AIDS patients (18%) was significantly higher than in the healthy volunteers group (3.33%). Regarding the serum level of anti T. gondii IgG antibodies among AIDS patients, it was 30% significantly higher compared with those of the seropositive healthy volunteers (6.67%). Conclusions: These statistically significant results support the association between T. gondii infection and AIDS and suggest the usefulness of providing data for an educational program that will be designed to prevent T. gondii infection among AIDS patients.

关键词： AIDS Toxoplasma gondii Anti T. gondii IgG Anti T. gondii IgM

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A Computational Comparison between Optimization Techniques for Wells Placement Problem: Mathematical Formulations, Genetic Algorithms and Very Fast Simulated Annealing

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Journal of Materials Science and Chemical Engineering 2014年第10期2卷 59-73页

作者： ghazi D. AlQahtani ahmed Alzahabi Timothy Spinner Mohamed Y. Soliman Saudi Aramco Dhahran KSA Texas Tech University Lubbock TX USA

This study considers several computational techniques for solving one formulation of the wells placement problem (WPP). Usually the wells placement problem is tackled through the combined efforts of many teams using conventional approaches, which include gathering seismic data, conducting real-time surveys, and performing production interpretations in order to define the sweet spots. This work considers one formulation of the wells placement problem in heterogeneous reservoirs with constraints on inter-well spacing. The performance of three different types of algorithms for optimizing the well placement problem is compared. These three techniques are: genetic algorithm, simulated annealing, and mixed integer programming (IP). Example case studies show that integer programming is the best approach in terms of reaching the global optimum. However, in many cases, the other approaches can often reach a close to optimal solution with much more computational efficiency.

关键词： Wells Placement Optimization Integer Programming Simulated Annealing Genetic Algorithm

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