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Contralateral eye study of refractive,topographic and aberrometric outcomes after femtosecond assisted Myo Ring implantation and DALK for management of keratoconus

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International Journal of Ophthalmology(English edition) 2018年第10期11卷 1621-1630页

作者： mohamed omar Yousif Azza mohamed Ahmed Said Department of Ophthalmology Faculty of Medicine Ain Shams University

AIM：To evaluate the efficacy of femtosecond laser assisted MyoRing intrastromal corneal implant and deep anterior lamellar keratoplasty （DALK） for management of moderate to advanced keratoconus regarding the degree of changes in visual acuity, refraction, corneal asphericity and ***：A prospective non comparative interventional case study was conducted in Ophthalmology Department,Ain Shams University Hospital in the period from January 2015 to February 2017. The study included 30 eyes of moderate to advanced keratoconus. MyoRing was implanted in one eye （Group Ⅰ） and DALK operation was performed in the contralateral eye of the same patient （Group Ⅱ）.Preoperative and 6mo post-operative uncorrected visual acuity（UCVA）, corrected distance visual acuity （CDVA）, spherical equivalent （SE）, corneal and refractive astigmatisms,keratometry and Q-value using topography images were acquired. Quality of vision was assessed in all eyes including total corneal, anterior corneal high order aberrations analysis at 5 mm pupil size and the Strehl ratio of point spread function （PSF） as an objective measure of ***：Mean postoperative UCVA, CDVA, SE, refractive astigmatism,keratometryreadingsandasphericity were statistically improved compared to preoperative parameters in both groups （P〈0.05）. Significant reduction of all corneal aberrations following both techniques（P〈0.05） was achieved except mean trefoil and mean PSF in Group Ⅰ （P〉0.05）. Postoperative corneal aberrations were significantly lower in Group Ⅱ compared to Group Ⅰ.A statistically significant negative correlation was found in Group Ⅰ between the mean change in CDVA （logMAR）and the mean preoperative and mean postoperative total corneal aberrations root mean square （RMS; r=-0.78,P=0.04）. Also a statistically significant negative correlation was found between mean preoperative coma RMS and mean post PSF （r=-0.86, P=0.01）. In Group Ⅱ, there was a statistically significant positive correlation between m

关键词： aberrations deep anterior lamellar keratoplasty femtosecond laser keratoconus MyoRing

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Nickel-titanium shape memory alloys made by selective laser melting:a review on process optimisation

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Advances in Manufacturing 2022年第1期10卷 24-58页

作者： omar Ahmed mohamed Syed Hasan Masood Wei Xu School of Engineering Deakin UniversityGeelongVIC 3216Australia Department of Mechanical Engineering The Higher Institute of Engineering TechnologyBani WaledLibya Department of Mechanical and Product Design Engineering Swinburne University of TechnologyHawthornVIC 3122Australia

Selective laser melting(SLM)is a mainstream powder-bed fusion additive manufacturing(AM)process that creates a three-dimensional(3D)object using a high power laser to fuse fine particles of various metallic powders such as copper,tool steel,cobalt chrome,titanium,tungsten,aluminium and stainless *** the past decade,SLM has received significant attention due to its capability in producing dense parts with superior mechanical *** a premier shape memory alloy,the nickel-titanium(NiTi)shape memory alloy is attractive for a variety of biomedical applications due to its superior mechanical properties,superelasticity,corrosion resistance and *** paper presents a comprehensive review of the recent progress in NiTi alloys produced by the SLM process,with a particular focus on the relationship between processing parameters,resultant microstructures and *** research gaps,challenges and suggestions for future research are also addressed.

关键词： Additive manufacturing(AM) Selective laser melting(SLM) Microstructure NiTi alloy Mechanical properties

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Modeling, analysis, and optimization of dimensional accuracy of FDM-fabricated parts using definitive screening design and deep learning feedforward artificial neural network

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Advances in Manufacturing 2021年第1期9卷 115-129页

作者： omar Ahmed mohamed Syed Hasan Masood Jahar Lal Bhowmik School of Engineering Deakin UniversityGeelongAustralia Department of Mechanical Engineering Higher Institute of Engineering TechnologyBani WalidLibya Department of Mechanical and Product Design Engineering Swinburne University of TechnologyHawthornVIC 3122Australia Department of Health Science and Biostatistics Swinburne University of TechnologyHawthornVIC 3122Australia

Additive manufacturing(AM)technologies such as fused deposition modeling(FDM)rely on the quality of manufactured products and the process ***,the dimensional accuracy and stability of any AM process is essential for ensuring that customer specifications are satisfied at the highest standard,and variations are controlled without significantly affecting the functioning of processes,machines,and product *** study aims to investigate the effects of FDM fabrication conditions on the dimensional accuracy of cylindrical *** this study,a new class of experimental design techniques for integrated second-order definitive screening design(DSD)and an artificial neural network(ANN)are proposed for designing experiments to evaluate and predict the effects of six important operating *** determining the optimum fabrication conditions to obtain better dimensional accuracies for cylindrical parts,the time consumption and number of complex experiments are reduced considerably in this *** optimum fabrication conditions generated through a second-order DSD are verified with experimental *** results indicate that the slice thickness,part print direction,and number of perimeters significantly affect the percentage of length difference,whereas the percentage of diameter difference is significantly affected by the raster-to-raster air gap,bead width,number of perimeters,and part print ***,the results demonstrate that a second-order DSD integrated with an ANN is a more attractive and promising methodology for AM applications.

关键词： Artificial neural network(ANN) OptimizationDefinitive screening design(DSD) Analysis of variance(ANOVA) Fused deposition modeling(FDM) Dimensional accuracy

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Robust Stabilization of Load Frequency Control System Under Networked Environment

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International Journal of Automation and computing 2017年第1期14卷 93-105页

作者： Ashraf Khalil Ji-Hong Wang omar mohamed Electrical and Electronics Engineering Department University of Benghazi Benghazi Libya School of Engineering University of Warwick Coventry UK King Abdullah Ⅱ Faculty of Engineering Princess Sumaya University of Technology Amman Jordan

The deregulation of the electricity market made the open communication infrastructure an exigent need for future power system. In this scenario dedicated communication links are replaced by shared networks. These shared networks are characterized by random time delay and data loss. The random time delay and data loss may lead to system instability if they are not considered during the controller design stage. Load frequency control systems used to rely on dedicated communication links. To meet future power system challenges these dedicated networks are replaced by open communication links which makes the system stochastic. In this paper, the stochastic stabilization of load frequency control system under networked environment is investigated. The shared network is represented by three states which are governed by Markov chains. A controller synthesis method based on the stochastic stability criteria is presented in the paper. A one-area load frequency control system is chosen as case study. The effectiveness of the proposed method for the controller synthesis is tested through simulation. The derived proportion integration （PI） controller proves to be optimum where it is a compromise between compensating the random time delay effects and degrading the system dynamic performance. The range of the PI controller gains that guarantee the stochastic stability is determined. Also the range of the PI controller gains that achieve the robust stochastic stability is determined where the decay rate is used to measure the robustness of the system.

关键词： Load frequency control load frequency control (LFC) Markov chains networked control system robust stabilization.

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Impacts of climate change on water quantity, water salinity, food security, and socioeconomy in Egypt

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Water Science and Engineering 2021年第1期14卷 17-27页

作者： Mohie El Din mohamed omar Ahmed Moustafa Ahmed Moussa Reinhard Hinkelmann National Water Research Center Fum Ismailiya CanalShoubra El-Kheima 13411Egypt International Center for Agricultural Research in the Dry Areas Cairo 2416Egypt Nile Research Institute(NRI) National Water Research CenterEl-Qanater 13621Egypt Department of Water Engineering Technische Universit€at Berlin(TU Berlin)Campus El GounaEl Gouna 84513Egypt

Climate change might have direct impacts on water quantity in Egypt and lead to indirect effects on Mediterranean saltwater intrusion to groundwater,which exposes agriculture to *** study investigated impacts of climate change on agriculture,with particular regard to food security and socioeconomy,and quantified the effectiveness of cropping pattern adaptation measures by integrating three mathematical *** BlueM model was used for hydrological simulations of Nasser Lake under flooding scenarios to predict the water supply from the High Aswan *** water and salinity balance(WB-SAL)model was adopted to estimate the water salinity in the Nile *** simulated results from the BlueM and WB-SAL models were integrated with the agricultural simulation model for Egypt(ASME)to project cropping patterns,food security,and socioeconomy throughout the *** results showed that future climate change will directly affect the total crop area;crop areas for 13 crop types;the self-sufficiency of wheat,rice,cereal,and maize supplies;and socioeconomic *** proposed cropping pattern adaptation measures focus on fixing the crop areas of rice and orchards and providing half of the population with lentils,maize,onion,vegetables,milk,and *** adaptation measures have the potential to promote food security without causing deterioration of the socioeconomic ***,water availability has much more significant effects on food security and socioeconomy than cropping pattern adaptation measures ***,the country should rationalize water use efficiency and increase water supply.©2021 Hohai *** and hosting by Elsevier *** is an open access article under the CC BY-NC-ND license(http://***/licenses/by-nc-nd/4.0/).

关键词： Climate change Water quantity Salinity Cropping pattern adaptation measures Food security Socioeconomy

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Optimization of fused deposition modeling process parameters:a review of current research and future prospects

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Advances in Manufacturing 2015年第1期3卷 42-53页

作者： omar A.mohamed Syed H.Masood Jahar L.Bhowmik Department of Mechanical and Product Design Engineering Faculty of ScienceEngineering and TechnologySwinburne University of TechnologyHawthornMelbourneAustralia Department of Psychological Sciences and Statistics Faculty of HealthArts and DesignSwinburne University of TechnologyHawthornMelbourneAustralia

Fused deposition modeling （FDM） is one of the most popuIar additive manufacturing technologies for various engineering applications. FDM process has been introduced commercially in early 1990s by Stratasys Inc., USA. The quality of FDM processed parts mainly depends on careful selection of process variables. Thus, identifica- tion of the FDM process parameters that significantly affect the quality of FDM processed parts is important. In recent years, researchers have explored a number of ways to improve the mechanical properties and part quality using various experimental design techniques and concepts. This article aims to review the research carried out so far in determining and optimizing the process parameters of the FDM process. Several statistical designs of experiments and optimization techniques used for the determination of optimum process parameters have been examined. The trends for future FDM research in this area are described.

关键词： Fused deposition modeling (FDM) -Experimental design. Additive manufacturing. Processparameters. Mechanical properties.Part quality

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Elective thoracotomy for pedicle screw removal to prevent severe aortic bleeding

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World Journal of Clinical Cases 2014年第4期2卷 100-103页

作者： Sebastian Decker mohamed omar Christian Krettek Christian W Müller Trauma Department Hannover Medical School30625 Hannover Germany

We present a case of a 33-year-old female who sustained multiple injuries of her spine, including spinous process fractures of C5 to C7 and a lamina fracture of C6 and C7. Her thoracic spine showed transverse process fractures of T4 to T10, a compression fracture and lamina fracture of T3, spinous process and transverse process fractures of T4 and T5, a rotation injury of T6, as well as a compression fracture of L1. Thirteen months after posterior thoracic spinal instrumentation, a pedicle screw was suspected to be in contact with the aorta, which was proved by computed tomography angiograms. Consequently, implant removal was planned with direct exposure of the aorta in order to allow for immediate repair if needed. So far, studies that compare different techniques to remove pedicle screws that are suspected to penetrate the aorta are missing. However, different techniques have been described in case reports, mainly minimally invasive endovascular techniques vs open techniques such as thoracotomy.

关键词： Spine Pedicle screw Aorta Bleeding Implant removal Hemorrhage

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Reasons for Dealing with a Particular Bank in the State of Libya

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Journal of Modern Accounting and Auditing 2018年第9期14卷 439-465页

作者： mohamed omar Fargani Al-Buraimi University College Oman

This section uses the results of a survey to find out how consumers evaluate banking services in the State of *** survey contained a large number of variables,most of which are *** paper tries to examine the relationships among the interrelated variables and represent them in terms of a few underlying *** is done through the use of the technique of Factor *** study represents an inquiry into consumers’evaluation of the banking system in Libya.A survey was conducted to collect information on a number of issues relating to the consumer’s views on various aspects of the structure and performance of commercial banks operating in the State of *** survey results were subjected to multivariate statistical *** technique of factor analysis was used to analyze the relationships among the interrelated variables affecting consumers’choice of a particular commercial *** principal component method,with varimax rotation,is utilized to reduce the large number of explanatory variables to a few underlying factors.

关键词： State of Libya commercial bank Factor Analysis varimax rotation

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Accidents during Tanker Accident in Confined Spaces

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Journal of Shipping and Ocean Engineering 2017年第5期7卷 203-209页

作者： omar mohamed Fouad Farid Maritime Safety Institute AAST & MT Alexandria 1029 Egypt

One of the major hazards when working onboard Tankers is working in confined spaces, improving the procedures in working in such spaces is obvious, but developing the equipments used in rescue operation is rare to happen, that＇s why this paper is focusing on differentiating between the manual ＆ more developed equipments used specially in rescuing the crew in such an adequate time, to save the workers＇ life. The manual way is called ＂MUCKY CRANE＂ which is used for rescue purposes onboard tankers, in any of the confined spaces, should be replaced by excel crane which is air or hydraulic driven machine, to achieve better results. As safety precautions measures taken in such tasks are not enough for the required objective achievement. Such safety procedures have been discussed and critical situations have been pointed out.

关键词： Hazards tankers confined spaces equipment development rescue operations mucky crane excel crane safetyprecautions measures critical situations.

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The impacts of altitude and seed pretreatments on seedling emergence of Syrian juniper (Juniperus drupacea (Labill.) Ant. et Kotschy)

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Ecological Processes 2021年第1期10卷 112-117页

作者： Cengiz Yucedag Mehmet Cetin Halil Baris Ozel Adel Easa Saad Abo Aisha Osama B.Muragaa Alrabiti Akram mohamed omar AL.JAMA Faculty of Engineering-Architecture Department of Landscape ArchitectureBurdur Mehmet Akif Ersoy UniversityBurdurTurkey. Faculty of Engineering and Architecture Department of Landscape ArchitectureKastamonu UniversityKuzeykent Campus37150 KastamonuTurkey Faculty of Forestry Department of Forest EngineeringBartin UniversityBartinTurkey Institute of Science and Technology Graduate Programs of Material Science and EngineeringKastamonu UniversityKastamonuTurkey.

Background:Syrian juniper is an economically important species and in danger of *** these reasons,the best seedling production methods of the species should be determined and its plantations should be *** aim of the study is to examine the impacts of altitude and different pretreatment combinations of cold and warm stratifications,citric acid,shaking seeds in bottles with crushed glass,and different stimulating agents including Baikal EM1,Biohumus,Polystimulin A6 and K hormones(PS-A6 and PS-K)on seed germination of Syrian *** conduct the study,the cones of the Syrian junipers were collected from three different altitudes(1000,1200,and 1400 m a.s.l.)within the boundaries of Forest Management Directorate of Bozyazı,Mersin in *** seeds were subjected to three replicates per one treatment(altitude in interaction with pretreatment).There were 100 seeds per ***:Two-way ANOVA revealed significant effects of altitude,pretreatment,and their interaction on seedling emergence of Syrian *** from higher altitudes had higher germination rates in all *** highest percent emergence(85%)was recorded in the combination consisting of shaking with crushed glass,both cold and warm stratification,and successive application of stimulators PS-A6 and *** the treatments with most germinating seeds encompassed shaking in crushed glass or soaking in citric acid,both warm and cold stratifications,and application of stimulating ***:The use of seeds from higher altitudes should be considered for seedling production of Syrian juniper due to their higher germination *** altitudinal differences,specific pretreatments can rise germination potential more than twofold.

关键词： Auxin Citric acid Cytokine Germination Stratification

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