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Effect of erosion on corrosion of API X120 steel in relation to erodent particle size

Journal of Iron and Steel Research International 2020年第6期27卷 691-701页

作者： Paul C.Okonkwo said Grami Srinivasan Murugan Shariq Khan Mechanical and Mechatronics Engineering Department College of EngineeringDhofar University211 SalalahOman Chemical Engineering College of EngineeringDhofar University211 SalalahOman

The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X120 steel was investigated using aluminum oxide and silicon carbide particles with different sizes as erodent and 3.5wt.% NaCl aqueous solution saturated with carbon dioxide as a corrosive medium. The effect of the erodent particle size on the corrosion behavior of the steel material at different particle speeds and impact angles was investigated using weight loss, potentiodynamic polarization and surface analysis techniques. The erosion results confirmed that the material damage increased with increasing particle speed. It was observed that in carbon dioxide-saturated saline solution, deposition of protective iron carbonate film occurred on the steel surface. It was found that the corrosion film can provide better protection at lower particle speed than at higher speed. The ratio of total erosion-corrosion (S)/effect of erosion on corrosion (T) analysis confirmed that at higher S/T ratio, the particle speed and material removal rate are low and vice versa at lower S/T ratio. Lower S/T values for the combined erosion and corrosion tests performed with erodent silicon carbide particle compared to erodent aluminum oxide particle showed that erosion enhancement of corrosion is more evident in the test performed using aluminum oxide particle than using silicon carbide particle. The result also suggests that when subjected to larger size erodent particle, the damage to pipeline due to effect of erosion on corrosion process can be more significant compared to smaller size erodent particle.

关键词： Erosion Corrosion API X120 steel Carbon dioxide Aluminum oxide Silicon carbide Erodent particlesize

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Delayed Grafting as a Valid Technique in Burn Management: Experience from a Burn Unit in Oman

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Modern Plastic Surgery 2024年第1期14卷 9-14页

作者： Taif Alsafy Joe Jacob Anish Thadathil Elias Ahmed Salah El Din Salim Mohammed Ghawas Majid Tariq Saud Albusaidi Ahmed Al Jabri Al Anood Al Hadhrami Mutazz Obeid Al Khaldi Moath Abdelhamid Shummo Karim Mohamed Haridi Aml Eid Saleh said Al-Busaidi Department of Plastic and Reconstructive Surgery Sultan Qaboos Hospital Salalah Oman ENT Department Al Nahdha Hospital Muscat Oman Department of Plastic Reconstructive and Craniofacial Surgery Khoula Hospital Muscat Oman

Background: Early excision and grafting has been the preferred method of managing major burns around the world since 1970. Considering the advances in health care and the development of new antibiotics over the past 50 years, delayed grafting as a technique for the management of burns over 15%-20% of total body surface area (TBSA) could have comparable results to that of early excision. This study aims to highlight the outcomes of practicing delayed grafting in burn patients. Methods: A case series analysis was performed of 51 patients who were admitted to the burns unit in Sultan Qaboos Hospital Salalah with over 20% TBSA between January 2014 and December 2019. The patients received prophylactic antibiotics and silver sulphadiazine dressing until the burn eschar had completely separated, followed by grafting. Results: Two patients were lost during the entire duration of the study. The mortality rate was comparable to that of early excision, while the rate of hypertrophic scarring was lower than the range reported by other studies. Conclusion: In the management of patients with over 20% TBSA, delayed grafting after complete separation of eschar is still a valid technique.

关键词： Burns Burn Units Burn Management Delayed Grafting Major Burns Treatment Efficacy

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Soil substrate as a cascade of capillary barriers for conserving water in a desert environment:lessons learned from arid nature

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Journal of Arid Land 2014年第6期6卷 690-703页

作者： Ali Al-MAKTOUMI said Al-ISMAILY Anvar KACIMOV Hamed Al-BUsaidI said Al-SAQRI Mansour Al-HADABI Department of Soils Water and Agricultural EngineeringSultan Qaboos UniversityPO Box 34 Al Khoud 123MuscatSultanate of Oman EcOman Centre Petroleum Development Oman LLC PO Box 81MuscatSultanate of Oman

Interaction between soil pedogenesis, subsurface water dynamics, climate, vegetation and human ingenuity in a desert environment has been found to result in a unique ecohydrological system with an essentially three dimensional sedimentation structure in the bed of a recharge dam in Oman. A 3-D array of silt blocks sand- wiched by dry sand-filled horizontal and vertical fractures was studied in pot experiments as a model of a natural prototype. Pots are filled with a homogenous sand-silt mixture （control） or artificially structured （smart design, SD） soil substrates. Rhodes grass and ivy （Ipomea, Convolvulaceae） were grown in the pots during the hottest season in Oman. Soil moisture content （SMC） was measured at different depths over a period of 20 days without irrigation. SD preserved the SMC of the root zone for both ivy and grass （SMC of around 25%-30% compared to 〈10% for control, 3 days after the last irrigation）. Even after 20 days, SMC was around 18% in the SD and 7% in the control. This, similar to the case of a natural prototype, is attributed to the higher upward capillary movement of water in control pots and intensive evaporation. The capillary barrier of sand sheaths causes discontinuity in moisture mi- gration from the micro-pores in the silt blocks to sand pores. The blocks serve as capillarity-locked water buffers, which are depleted at a slow rate by transpiration rather than evaporation from the soil surface. This creates a unique ecosystem with a dramatic difference in vegetation between SD-pots and control pots. Consequently, the Noy-Meir edaphic factor, conceptualizing the ecological impact of 1-D vertical heterogeneity of desert soils, should be generalized to incorporate 3-D soil heterogeneity patterns. This agro-engineering control of the soil substrate and soil moisture distribution and dynamics （SMDaD） can be widely used by desert farmers as a cheap technique, with significant savings of irrigation water.

关键词： soil capillary barrier infiltration soil heterogeneity ecohydrology hydropedology plant root soil moisture content

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Assessment of Left Ventricular Mechanical Function in Cardiac Syndrome X: Speckle Tracking Imaging Study

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World Journal of Cardiovascular Diseases 2018年第12期8卷 557-568页

作者： mahmoud Kamel Ahmed Emara said Shalaby Montaser mahmoud said Menufia University Hospital Shibin El Kom Egypt

Objective: Early detection of LV mechanical abnormalities in patients with cardiac syndrome X (CSX) by speckle tracking echocardiography (STE). Background: Cardiac syndrome X is a triad of angina pectoris, positive stress test for myocardial ischemia and angiographically free coronary arteries. Two dimensional speckle tracking?echocardiography (2D-STE) provides a more sensitive method for evaluation of global and segmental LV function than conventional two dimensional echocardiographic parameters. Subjects and Methods: Seventy patients proved to have CSX and 20 healthy control volunteers were included with a mean age of 49.43 ± 5.92 vs. 49.40 ±6.27 years respectively with no difference regarding sex for both patients and controls. Patients with hypertension, diabetes mellitus, valvular heart disease, cardiomyopathies, inflammatory diseases, myocarditis and arrhythmias were excluded. All included individuals were subjected to complete conventional echocardiographic assessment and left ventricular global and segmental mechanical function was assessed using 2D based strain and strain rate (longitudinal, radial and circumferential) imaging. Results: There was no statistically significant difference in LV conventional echo parameters between patients and controls. However, global mean longitudinal strain was significantly lower in patients than controls (-15.05 ± 3.28 vs. -20.22 ± 2.49;p 0.001). For radial and circumferential strain stain, there was no significant changes between patients vs. controls (29.75 ± 18.26 vs. 28.09 ± 15.48;p = 0.74) and (-19.88 ± 8.63 vs. -21.93 ± 5.69;p 0.05) respectively. Conclusion: In spite of normal conventional echo parameters among patients and controls, LV longitudinal strain and strain rate by 2D speckle tracking imaging were lower in the patients denoting subclinical left ventricular mechanical dysfunction in patients with CSX.

关键词： Cardiac Syndrome X Left Ventricular Systolic and Diastolic Function 2D-Speckle Tracking Strain and Strain Rate Imaging

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An Intelligent Adaptive Dynamic Algorithm for a Smart Traffic System

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Computer Systems Science & Engineering 2023年第7期46卷 1109-1126页

作者： Ahmed Alsheikhy Yahia said Tawfeeq Shawly Electrical Engineering Department College of EngineeringNorthern Border UniversityArarSaudi Arabia Electrical Engineering Department Faculty of Engineering at RabighKing Abdulaziz UniversityJeddahSaudi Arabia

Due to excessive car usage,pollution and traffic have *** urban cities in Saudi Arabia,such as Riyadh and Jeddah,drivers and air quality suffer from traffic *** the government has implemented numerous solutions to resolve this issue or reduce its effect on the environment and residents,it still exists and is getting *** paper proposes an intelligent,adaptive,practical,and feasible deep learning method for intelligent traffic *** uses an Internet of Things(IoT)sensor,a camera,and a Convolutional Neural Network(CNN)tool to control traffic in real *** image segmentation algorithm analyzes inputs from the cameras installed in designated *** study considered whether CNNs and IoT technologies could ensure smooth traffic flow in high-speed,high-congestion *** presented algorithm calculates traffic density and cars’speeds to determine which lane gets high priority first.A real case study has been conducted on MATLAB to verify and validate the results of this *** algorithm estimates the reduced average waiting time during the red light and the suggested time for the green and red *** assessment between some literature works and the presented algorithm is also *** contrast to traditional traffic management methods,this intelligent and adaptive algorithm reduces traffic congestion,automobile waiting times,and accidents.

关键词： Smart traffic control artificial intelligence traffic congestion IoT CNN smart roads

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A New Sliding Function for Discrete Predictive Sliding Mode Control of Time Delay Systems

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International Journal of Automation and computing 2013年第4期10卷 288-295页

作者： Abdennebi Nizar Ben Mansour Houda Nouri Ahmed said Numerical Control of Industrial Processes National Engineering School of Gabes University of Gabes

The control of time delay systems is still an open area for research. This paper proposes an enhanced model predictive discrete-time sliding mode control with a new sliding function for a linear system with state delay. Firstly, a new sliding function including a present value and a past value of the state, called dynamic surface, is designed by means of linear matrix inequalities （LMIs）. Then, using this dynamic function and the rolling optimization method in the predictive control strategy, a discrete predictive sliding mode controller is synthesized. This new strategy is proposed to eliminate the undesirable effect of the delay term in the closed loop system. Also, the designed control strategy is more robust, and has a chattering reduction property and a faster convergence of the system s state. Finally, a numerical example is given to illustrate the effectiveness of the proposed control.

关键词： State time delay systems discrete sliding mode control model predictive control dynamic sliding function linear matrix inequalities (LMIs) chattering.

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Hydrogen FBG Sensor Using Pd/Ag Film With Application in Propulsion System Fuel Tank Model of Aerospace Vehicle

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Photonic Sensors 2014年第3期4卷 254-264页

作者： said SAAD Lotfi HASSINE Vassim ELFAHEM Group of Electronics and Quantum Physics Laboratory of Advanced Materials and Quantum Phenomena Faculty ofSciences of Tunis 2092 Tunisia National Institute of Applied Sciences and Technology University of Carthage North Urban Center of Tunis-B.P. 676Cedex Tunis 1080 Tunisia Regio iT Gesellschaft mit beschrankter Hafiung Aachen Germany

The high efficiency hydrogen fiber Bragg grating （FBG） sensor is presented. The sensitive film was a new alliance of palladium-silver （Pd-Ag）. In addition, the titanium （Ti） layer was used as the adhesive layer. The presented sensor showed the resolution of more than 60pm/1%H2, and a fast response time of4s - 5s was guaranteed in the 0.1%H2 - 4%H2 range. Moreover, the life time of the sensor was investigated. The obtained results showed that the sensor had an enhanced life time. Furthermore, the sensor was applied in the propulsion system fuel tank model of the aerospace vehicle. The obtained results indicated that it is a prevention system against the disaster aerospace due to hydrogen leakage.

关键词： Hydrogen fiber Bragg grating palladium-silver faster response time propulsion system fuel tank prevention system hydrogen leakage

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Merging control strategies of connected and autonomous vehicles at freeway on-ramps:a comprehensive review

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Journal of Intelligent and Connected Vehicles 2022年第2期5卷 99-111页

作者： Jie Zhu said Easa Kun Gao Department of Architecture and Civil Engineering Chalmers University of TechnologyGothenburgSweden Department of Civil Engineering Ryerson UniversityTorontoCanada

Purpose–On-ramp merging areas are typical bottlenecks in the freeway network since merging on-ramp vehicles may cause intensive disturbances on the mainline traffic flow and lead to various negative impacts on traffic efficiency and *** connected and autonomous vehicles(CAVs),with their capabilities of real-time communication and precise motion control,hold a great potential to facilitate ramp merging operation through enhanced coordination *** paper aims to present a comprehensive review of the existing ramp merging strategies leveraging CAVs,focusing on the latest trends and developments in the research ***/methodology/approach–The review comprehensively covers 44 papers recently published in leading transportation *** on the application context,control strategies are categorized into three categories:merging into sing-lane freeways with total CAVs,merging into singlane freeways with mixed traffic flows and merging into multilane ***–Relevant literature is reviewed regarding the required technologies,control decision level,applied methods and impacts on traffic *** importantly,the authors identify the existing research gaps and provide insightful discussions on the potential and promising directions for future research based on the review,which facilitates further advancement in this research ***/value–Many strategies based on the communication and automation capabilities of CAVs have been developed over the past decades,devoted to facilitating the merging/lane-changing maneuvers at freeway *** the significant progress made,an up-to-date review covering these latest developments is missing to the authors’best *** paper conducts a thorough review of the cooperation/coordination strategies that facilitate freeway on-ramp merging using CAVs,focusing on the latest developments in this *** on the review,the authors identify the existing research gaps in CAV r

关键词： Ramp merging Connected and autonomous vehicles Vehicle coordination Mixed traffic Multilane freeway

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Turbulent Double-Diffusive Natural Convection and Entropy Generation within an Inclined Square Cavity

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Fluid Dynamics & Materials Processing 2022年第6期18卷 1619-1629页

作者： Khaled said Ahmed Ouadha Amina Sabeur Laboratoire des Sciences et Ingénierie Maritimes Facultéde Génie MécaniqueUniversitédes Sciences et de la Technologie Mohamed BOUDIAF d’OranOran El-MnouarAlgérie

The present study deals with double-diffusive convection within a two-dimensional inclined cavity filled with an air-CO_(2) binary gas *** left and the right vertical walls are differentially heated and subjected to different locations of(CO_(2))contaminants to allow for the variation of the buoyancy strength(N).However,the horizontal walls are assumed *** simulations are conducted using the finite volume method to solve the conservation equations of continuity,momentum,energy,and species *** agreement with other numerical results in the literature is *** effect of multiple parameters,namely,buoyancy ratio(N),thermal Rayleigh number(Ra),and inclination angle(α)on entropy generation rate is analyzed and discussed in the postprocessing stage,while considering both laminar and turbulent flow *** computations reveal that these parameters considerably affect both the heat and mass transfer performances of the system.

关键词： CFD entropy generation double diffusive convection inclination angle CO_(2) turbulent regime

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Effect of band gap energy on the electrical conductivity in doped ZnO thin film

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Journal of Semiconductors 2014年第7期35卷 19-22页

作者： said Benramache Okba Belahssen Hachemi Ben Temam Physic Laboratory of Thin Films and Applications LPCMA University of BiskraBiskra 07000Algeria

The transparent conductive pure and doped zinc oxide thin films with aluminum, cobalt and indium were deposited by ultrasonic spray technique on glass substrate at 350 ℃. This paper is to present a new approach to the description of correlation between electrical conductivity and optical gap energy with dopants＇ concentration of A1, Co and In. The correlation between the electrical and optical properties with doping level suggests that the electrical conductivity of the films is predominantly estimated by the band gap energy and the concentrations of A1, Co and In. The measurement in the electrical conductivity of doped films with correlation is equal to the experimental value, the error of this correlation is smaller than 13%. The minimum error value was estimated in the cobalt-doped ZnO thin films. This result indicates that such Co-doped ZnO thin films are chemically purer and have far fewer defects and less disorder owing to an almost complete chemical decomposition.

关键词： ZnO thin films semiconductor doping electrical conductivity optical gap energy correlation

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