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Evaluation of implanted perforated lacrimal punctal plugs using anterior segment optical coherence tomography

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Eye and Vision 2021年第1期8卷 366-373页

作者： Raafat Mohyeldeen Abdelrahman Abdallah Ahmed Mohamed Kamal Elshafei Heba radi AttaAllah Ophthalmology Department Minia UniversityEl‑MiniaEgypt Ophthalmology Department Minia University HospitalEl‑MiniaEgypt

Purpose:Evaluation of the patency and position of perforated lacrimal punctal plugs implanted for treating punctal stenosis together with quantitative assessment of the precorneal tear film using anterior segment optical coherence tomography(AS-OCT).Methods:In a prospective study,the lower punctum of 54 eyes of 29 patients implanted with perforated punctal plugs were examined using AS-OCT during the early postoperative *** tear meniscus height(TMH)and tear meniscus area(TMA)were ***,the patency of the plug,its position,TMH and TMA were evaluated,and the results were correlated with postoperative *** scale was used for epiphora ***:Using AS-OCT,48(88.9%)plugs were found in proper position while 6(11.1%)were *** lumen of the plugs was completely patent in 47(87%)plugs,partially obstructed in 2(3.7%)plugs and completely occluded in 5(9.2%)*** was a statistically significant postoperative decrease of TMH and TMA(P<0.001)and postoperative epiphora Munk score(P<0.001).Conclusion:AS-OCT is a valuable,reliable,and noninvasive investigative tool that can detect the proper positioning,patency,and contents of the implanted perforated lacrimal punctal plugs in addition to measurement of TMH and TMA.

关键词： AS-OCT Perforated plugs Plugs

Correlation between corneal demarcation line depth in epithelium-off and trans-epithelium accelerated corneal cross linking and keratoconus progression

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International Journal of Ophthalmology(English edition) 2020年第6期13卷 907-912页

作者： Mahmoud Abdel-radi Zeiad Eldaly Hazem Abdelmotaal Reham Abdelrahman Mohamed Sayed Kamel Soliman Department of Ophthalmology Assiut UniversityAssiut 71516Egypt

AIM:To compare corneal demarcation line(DL)depth in both accelerated epithelium-off and trans-epithelium cross linking(CXL)using anterior segment optical coherence tomography(AS-OCT)and its relation to maximum keratometry(Kmax)progression in both ***:A prospective comparative interventional study where patients with mild to moderate keratoconus(KC)were classified into two groups:accelerated epitheliumoff and trans-epithelium CXL based on corneal *** of corneal DL depth was carried out after 3mo by *** readings were evaluated after one year follow up using the Scheimpflug imaging ***:Study included 74 eyes of 44 *** A underwent epithelium-off CXL(41 eyes),while Group B underwent trans-epithelium CXL(33 eyes).At 3mo follow up,mean corneal DL depth in Group A was 219.9±58.4μm while in Group B was 127.2±7.8μm(P0.05).In addition,no significant change in corneal pachymetry was found in both groups(meanchange at 1y:6.4±4.7 and-10.1±2.3μm in Groups A and B respectively).CONCLUSION:Despite a significantly deeper corneal DL depth created by accelerated epithelium-off CXL technique compared to accelerated trans-epithelium CXL,there is no significant impact on keratoconus progression.

关键词： anterior segment optical coherence tomography cross linking demarcation line keratoconus

Interference-Aware Multipath Routing Protocol for QoS Improvement in Event-Driven Wireless Sensor Networks

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Tsinghua Science and Technology 2011年第5期16卷 475-490页

作者： Marjan radi Behnam Dezfouli Kamalrulnizam Abu Bakar Shukor Abd Razak Mohammad Ali Nematbakhsh Faculty of Computer Science and Information Systems Universiti Teknologi Malaysia Faculty of Computer Engineering University of Isfahan

The existing multipath routing protocols for wireless sensor networks demonstrate the efficacy of traffic distribution over multiple paths to fulfill the Quality of Service （QoS） requirements of different applications. However, the performance of these protocols is highly affected by the characteristics of the wireless channel and may be even inferior to the performance of single-path approaches. Specifically, when multiple adjacent paths are being used concurrently, the broadcast nature of wireless channels results in inter-path interference which significantly degrades end-to-end throughput. In this paper, we propose a Low- Interference Energy-efficient Multipath Routing protocol （LIEMRO） to improve the QoS requirements of event-driven applications. In addition, in order to optimize resource utilization over the established paths, LIEMRO employs a quality-based load balancing algorithm to regulate the amount of traffic injected into the paths. The performance gain of LIEMRO compared to the ETX-based single-path routing protocol is 85%, 80%, and 25% in terms of data delivery ratio, end-to-end throughput, and network lifetime, respectively. Furthermore, the end-to-end latency is improved more than 60%.

关键词： LIEMRO QoS load balancing interference multipath routing event-driven

Anodic voltammetric determination of gemifloxacin using screen-printed carbon electrode

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Journal of Pharmaceutical Analysis 2013年第2期3卷 132-136页

作者： Abd-Elgawad radi Amira Khafagy Amira El-shobaky Hatem El-mezayen Department of Chemistry Faculty of ScienceDumyat University Department of Chemistry Faculty of ScienceHelwan University

The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon *** effects of pH,scan rates,and concentration of the drug on the anodic peak current were *** of gemifloxacin in Tris-HCl buffer（pH 7.0） exhibited a well-defined single oxidation peak.A differential-pulse voltammetric procedure for the quantitation of gemifloxacin has been developed and suitably validated with respect to linearity,limits of detection and quantification,accuracy,precision,specificity,and *** calibration was linear from 0.5 to 10.0 μM,and the limits of detection and quantification were 0.15 and 5.0 μ*** ranging from 96.26% to 103.64% were *** method was successfully applied to the determination of gemifloxacin in pharmaceutical tablets without any *** present in the tablets did not interfere in the assay.

关键词： Screen-printed carbon electrode Voltammetry Gemifloxacin Pharmaceutical analysis

Increasing Equal Opportunities in Education in *** Development Programmes of the“GENIUS”Charity Foundation

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Sociology Study 2020年第1期10卷 42-51页

作者： Natália Váradi Ferenc Rákóczi II.Transcarpathian Hungarian Institute and“GENIUS”Charity Foundation BeregszászUkraine

The essential condition of the economic evolution in Transcarpathia is the assistance of young researchers,finding the young talents,supporting their development as well as finding those young people with outstanding achievements and with appropriate *** for,identifying,and developing young people with outstanding abilities is a determining key factor of the competitiveness of a given region;in such a work,a prominent role is given to different educational institutions and talent *** concerning this reason,“GENIUS”Charity Foundation has been established in *** carries out a wide range of talent management,talent development and research among the schoolchildren,students,and young *** aim is to create an integrated system of the talent support programs,to assure equal access in promoting talents,and increase the talented youth’s social *** Foundation among many others,organizes the Conference of Young Researchers,as well as the Conference of Scientific Students,and operates the nine Talent Points where more than 2,000 children,more than 300 qualified teachers,and nearly 90 schools take part.

关键词： talent development equal opportunities best practice talent management diversity management

Thermal-Mechanical Coupled FE Analysis for Rotary Shaft Seals

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Modern Mechanical Engineering 2018年第1期8卷 95-110页

作者： Gyorgy Szabó Károly Váradi Department of Machine and Product Design Budapest University of Technology and EconomicsBudapestHungary

The aim of this paper is to model the steady-state condition of a rotary shaft seal (RSS) system. For this, an iterative thermal-mechanical algorithm was developed based on incremental finite element analyzes. The behavior of the seal’s rubber material was taken into account by a large-strain viscoelastic, so called generalized Maxwell model, based on Dynamic Mechanical Thermal Analyses (DMTA) and tensile measurements. The pre-loaded garter spring was modelled with a bilinear material model and the shaft was assumed to be linear elastic. The density, coefficient of thermal expansion and the thermal conductance of the materials were taken into consideration during simulation. The friction between the rotary shaft seal and the shaft was simplified and modelled as a constant parameter. The iterative algorithm was evaluated at two different times, right after assembly and 1 h after assembly, so that rubber material’s stress relaxation effects are also incorporated. The results show good correlation with the literature data, which state that the permissible temperature for NBR70 (nitrile butadiene rubber) material contacting with ~80 mm shaft diameter, rotating at 2600/min is 100°C. The results show 107°C and 104°C for the two iterations. The effect of friction induced temperature, changes the width of the contact area between the seal and the shaft, and significantly reduces the contact pressure.

关键词： Coupled FE Analysis Thermal-Mechanical Coupling Rotary Shaft Seals NBR Rubber Viscoelasticity

Numerical investigation to evaluate the effects of gravity and pressure on flame structure and soot formation of turbulent non-premixed methaneair flame

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Propulsion and Power Research 2022年第4期11卷 473-495页

作者： Subrat Garnayak Amjad Ali Pasha radi Alsulami Medhat A.Nemitallah Abdul Gani Abdul Jameel Sukanta K.Dash V.Mahendra Reddy School of Energy Science&Engineering Indian Institute of Technology KharagpurWest Bengal721302India Department of Aerospace Engineering King Abdulaziz UniversityJeddah21589Saudi Arabia Department of Mechanical Engineering King Abdulaziz UniversityJeddah21589Saudi Arabia IRC-Hydrogen and Energy Storage and Mechanical Engineering Department King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Department of Chemical Engineering King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Center for Refining&Advanced Chemicals King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Department of Mechanical Engineering Indian Institute of Technology KharagpurWest Bengal721302India

In this study,a turbulent non-premixed(diffusion)methane-air flame has been investigated computationally to analyze the influences of pressure and gravity on flame structure and sooting characteristics between 1 and 10 *** simulation has been conducted in a 2-D axisymmetric computational domain using the finite volume-based computational fluid dynamics(CFD)*** interaction of turbulence and chemistry is modeled by considering the steady laminar flamelet model(SLFM)and the GRI Mech 3.0 chemical *** radiative heat transfer calculation is carried out by considering the discrete ordinate(DO)method and the weighted sum grey gas model(WSGGM).The semi-empirical Moss-Brookes model is considered to calculate *** impact of gravity on flame and sooting characteristics are evaluated by comparing the normal-gravity flames with the zero-gravity *** effect of soot and radiation on flame temperature is also *** results show a close agreement with the measurement when both soot and radiation are included in the numerical *** rates of soot formation,surface growth,and oxidation increase with increased operating pressure,regardless of ***-gravity flames have a higher soot volume fraction,a wider soot-containing zone,a higher CO mass fraction,and a lower flame temperature than normal-gravity flames while maintaining constant *** normal-gravity flames,the CO mass fraction decreases with pressure,whereas it increases with pressure rise in flames of zero *** of zero gravity appear taller and broader compared to the flames of normalgravity for a fixed *** increase in pressure significantly reduces the flame length and width in normal-gravity ***,the pressure elevation has little effect on the shape of a zero-gravity *** outcomes of the present study will assist in fully understanding the combustion and sooting characteristics of turbulent diffusion flames that will help design and develop h

关键词： Computational fluid dynamics(CFD) Flamelet Gravity Pressure Soot

Improving the Thermal Efficiency and Performance of Refrigeration Systems:Numerical-Experimental Analysis of Minimization of Frost Formation

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Energy Engineering 2022年第5期119卷 1771-1788页

作者： Felipe Mercês Biglia Raquel da Cunha Ribeiro da Silva Fátima deMoraes Lino Kamal Abdel radi Ismail Thiago Antonini Alves Federal University of Technology-Parana(UTFPR) CuritibaBrazil Federal University of Technology-Parana(UTFPR) GuarapuavaBrazil University of Campinas(UNICAMP) CampinasBrazil Federal University of Technology-Parana(UTFPR) Ponta GrossaBrazil

The frost growth on cold surfaces in evaporators is an undesirable phenomenon which becomes a problem for the thermal efficiency of the refrigeration systems because the ice layer acts as a thermal insulation,drastically reducing the rate of heat transfer in the *** accumulation implies an increase in energy demand and a decrease in the performance of various components involved in the refrigeration process,reducing its efficiency and making it necessary to periodically remove the frost,resulting in expenses for the defrost *** the present work,a numerical-experimental analysis was performed in order to understand the formation process of porous ice in flat plates with different surface treatments and *** understanding is of utmost importance to minimize the formation of porous ice on cold surfaces and improve equipment efficiency and *** this context,a low-cost experimental apparatus was developed,enabling an experimental analysis of the phenomenon under *** environmental conditions evaluated are the temperature of the cold surface,roomtemperature,humidity,and air *** material of the surfaces under study are aluminum,copper,and brass with different surface finishes,designated as smooth,grooved(hydrophilic),and varnished(hydrophobic).The numerical-experimental analysis demonstrates measurements and simulations of the thickness,surface temperature,and growth rate of the porous ice layer as a function of the elapsed *** numerical results were in good agreement with the experimental results,indicating that the varnished surface,with hydrophobic characteristics,presents greater difficulty in providing the ***,the results showed that application of a coating allowed a significant reduction on the frost formation process contributing to the improvement of thermal efficiency and performance of refrigeration systems.

关键词： Frost layer growth frost thickness minimization of frost hydrophobic surface refrigeration systems

Failure Mechanism of O-Ring Seals under Extreme Operating Conditions

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Modern Mechanical Engineering 2018年第1期8卷 11-30页

作者： Gyorgy Szabó Károly Váradi Department of Machine and Product Design Budapest University of Technology and EconomicsBudapestHungary

In this paper the behavior of an O-ring made of NBR rubber was investigated under extreme conditions. The effect of the extreme initial compression, operating pressure and extreme temperature conditions were examined. The rubber material was tested in simple tension, pure shear and equibiaxial tension modes complemented with a Dynamic Mechanical Thermal Analysis (DMTA) to capture the viscoelastic behavior of the material. For the investigation, a large-strain viscoelastic material model was developed by the authors, to take into account the large deformations caused by extreme conditions. Insufficient space during installation causes extreme initial compression consequently leading the material to crack on the contacting outer surfaces. It was found that the excessive strain and friction induced shear stress contributes primarily to this phenomenon. Extreme operating pressure causes the seal to penetrate into the gap between the shaft and the housing. This behavior damages the material and cracks appear on the seal. High strain areas were found in the proximity of the gap in the material. The analysis of the extreme operating temperature showed that during cooling the O-ring can completely loose its ability to seal at -70°C. There are three contributing factors: the speed of cooling, the temperature and the coefficient of thermal expansion.

关键词： O-Rings Finite Element Analysis Initial Pressure Overpressure Temperature Extremes