Near-Nozzle Liquid Flow and Spray Characteristics of DISI Swirl Injectors

( Essam Abo Serie ),( Seok Su Moon ),( Choong Sik Bae ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-

A simple model has been employed in this study to identify the liquid film and spray profile near the nozzle exit of DISI swirl injectors. The forces acting on the liquid film after it emerges from the nozzle cause the film to diverge away from the nozzle centerline forming a conical spray structure. After the film breaks-up, the separated droplets from the liquid film are then further diverged until an asymptotic divergence angle which is equal to the nozzle spray angle is reached. The envelop of the liquid film and spray droplets motion was compared with the spray images close to the nozzle exit to identify the initial velocity of the droplets after film break-up. A parametric study examining the factors affecting the initial formation of spray has been performed and three angles have been distinguished; flow angle at the nozzle exit, liquid film divergent angle and nozzle spray angle. The factors affecting each of the three angles have been investigated and the relationship between these angles is also deduced. The model showed a reasonable agreement with the experimental results although further development could be achieved to improve the accuracy of prediction. This model could easily be implemented as a sub-model to link the internal nozzle flow model with the conventional spray model. It also provides an estimate for the necessary initial conditions needed for the atomization and spray models.

Study on Microstructure Characterisation of Three Different Surface Coating Techniques on 6082-T6 Aluminum Alloy

Essam R. I. Mahmoud,Ali Algahtani,Vineet Tirth 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

The aim of this study was to investigate the detailed macro/microstructures of three different surface coating technologieson the 6082-T6 aluminum alloy surface, namely Plasma Electrolytic Oxidation (PEO), Hard Anodizing (HA), and PlasmaSpray Ceramic (PSC). Some of the PEO coatings were sealed with silicates. The microstructure investigations were performedusing optical microscope, scanning electron microscope equipped with EDX analyzer and X-ray diffractometer. Themicrohardness of the base material and the coated layer were evaluated using Knoop indenter. All the coated layers appearedas two different layers. The PSC coating was the thicker followed by HA then PEO coating. The HA coating had irregularsurface appearance, contained some cracks and appeared as an amorphous structure. The PSC coating was loose and hada poor bond with the substrate. The structure of PSC coating exhibited a lamellar geometry configuring 14% α-Al2O3 and86% γ-Al2O3. The presence of porosity and voids was also observed. The PEO coatings were uniform and comprehensive. Itadhered quite well to the substrate consisting of alumina (α and γ) phases. The ratio of γ alumina to α alumina was 79:31%. The sealed PEO coating with silicate had much lower porosity especially in the outer layer. All the coatings exhibited higherhardness than the substrate. The PEO coating showed the highest hardness compared with other coatings. The hardness ofthe PEO coating improved as the readings were taken away from the base. It displayed a maximum value in the middle andthen started to reduce. The PSC coating has the highest roughness value followed by HA and then PEO coatings.

Pi2 Pulsations During Extremely Quiet Geomagnetic Condition: Van Allen Probe Observations

Essam Ghamry 한국우주과학회 2017 Journal of Astronomy and Space Sciences Vol.34 No.2

A ultra low frequency (ULF) wave, Pi2, has been reported to occur during periods of extremely quiet magnetospheric and solar wind conditions. And no statistical study on the Pi2 has been performed during extremely quiet conditions, using satellite observations to the author’s knowledge. Also Pi2 pulsations in the space fluxgate magnetometers near perigee failed to attract scientist’s attention previously. In this paper, Pi2 pulsations detected by the Van Allen probe satellites (VAP-A & VAP-B) were investigated statistically. During the period from October 2012 to December 2014, ninety six Pi2 events were identified using VAP when Kp = 0 while using Kakioka (KAK, L = 1.23) as a reference ground station. Seventy five events had high coherence between VAP-Bz and H components at KAK station. As a result, it was found that 77 % of the events had power spectra between 5 and 12 mHz, which differs from the regular Pi2 band range of from 6.7 to 25 mHz. In addition, it was shown that it is possible to observe Pi2 pulsations from space fluxgate magnetometers near perigee. Twenty two clean Pi2 pulsations were found where L < 4 and four examples of Pi2 oscillations at different L shells are presented in this paper.

On the Performance of All-optical Amplify-and-forward Relaying with a Backup Radio-frequency Link Over Strong Atmospheric Turbulence and Misalignment Fading

Essam Saleh Altubaishi 한국광학회 2021 Current Optics and Photonics Vol.5 No.2

Free-space optical (FSO) communication is considered to be a potential solution to congestion in the radio-frequency spectrum and last-mile-access bottleneck issues in future cellular communication networks, such as 5G and beyond. However, FSO link performance may degrade significantly due to irradiance fluctuations and random temporal fluctuations from atmospheric turbulence. Therefore, in this work the main objective is to reduce the effect of the atmospheric turbulence by considering a multihop FSO communication system with amplify-and-forward relaying supported by a radio-frequency (RF) link, which form a hybrid FSO/RF communication system. The FSO link is assumed to follow the gamma-gamma fading model, which represents strong turbulence. Also, the RF link is modeled by a Rayleigh distribution. The performance of the considered system, in terms of the outage probability and average bit-error rate (BER), is investigated and analyzed under various weather conditions and pointing errors. Furthermore, the effect of the number of employed relay nodes on the performance of the system is investigated. The results indicate that the considered system reduces outage probability and average BER significantly, especially for low channel quality. Finally, the closed-form expressions derived in this work are compared to the results of Monte Carlo simulations, for verification.

Energy Performance Analyses in Low Carbon Buildings

( Essam E Khalil ),( Fellow Asme ),( Fellow Ashrae ),( Fellow Aiaa ) 경남대학교 신소재연구소 2012 신소재연구 Vol.24 No.-

The Developing communities in their path for rapid development is endeavoring to make all necessary and appropriate measures to enhance the efficiency of energy utilization and increase the beneficiation of the energy resources. The energy production, transmission, distribution and utilization efficiency becomes a vital factor and measure of national development. Governmental organizations were established earlier to be responsible for energy planning and efficient utilization, information dissemination and capacity building as well as devising the necessary codes and standards. Throughout the Nation Energy resources are widely used and consumption rates are in general exceeding the International accepted values. Energy rationalization and audit exercises were developed and monitored by Governmental authorities, Universities and Research centers through the past two decades with a definitive positive energy reduction and beneficiation. The development of the relevant codes for Residential and Commercial Energy Efficiency in Building is underway through the governmental bodies responsible for the research and development in the building Technology sector and is the umbrella under which the National and Unified Arab Codes are developed and issued. A proposed new Energy Performance in Buildings Directive would fulfill the following main targets of Energy Performance Directive: 1. “Legestilative authorities shall ensure that, when buildings are constructed, sold or rented out, an energy performance certificate is made available to the owner or by the owner to the prospective buyer or tenant, as the case might be. … 2. The energy performance certificate for buildings shall include reference values such as currant legal standards and benchmarks in order to make it possible for consumers to compare and assess the energy performance of the building. The certificate shall be accompanied by recommendations for cost-effective improvement of the energy performance…” The following steps are required for the energy certification: 1. Develop methodologies for energy declaration of the buildings 2. Develop reference values (key numbers) and /or systems for benchmarking 3. Provide a labeling system for selected buildings 4. Describe an energy signature for the building.

Intuitionistic fuzzy topological spaces: Categorical concepts

Essam Hamouda 원광대학교 기초자연과학연구소 2017 ANNALS OF FUZZY MATHEMATICS AND INFORMATICS Vol.13 No.2

Coker has introduced the concept of intuitionistic fuzzy topological spaces $(X,T)$ where $X$ is an ordinary set and $T$ is a family of intuitionistic fuzzy sets in $X$ satisfying some axioms. In this paper I introduce the fuzzy version of some universal constructions, namely, fuzzy products, fuzzy equalizers and fuzzy pullbacks for intuitionistic fuzzy topological spaces. Some results concerning all such universal objects are discussed. Finally, functors preserving equalizers and pullbacks are investigated.

Configuration design of ten-speed automatic transmissions with twelve-link three-DOF Lepelletier gear mechanism

Essam L. Esmail 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.1

Many Lepelletier-type automatic transmissions are in production. Some of Lepelletier related configurations are still far from reachingmaximum possible sequential speed ratios. This work focuses on analyzing and developing twelve-link three-DOF Lepelletier-type automatictransmissions to attain maximum speed ratios. Following the general trend of increased shift stages and a wider range of speedratios, new ten-speed automatic transmissions are enumerated from the twelve-link three-DOF Lepelletier gear mechanisms. Furthermore,a ten-speed automatic transmission is modified from an existing eight-speed Lepelletier-type automatic transmission. The results showthat the twelve-link three-DOF Lepelletier gear mechanism could reach eleven forward speeds at most. Nomographs are shown to bepractical in detecting possible configurations and their clutching sequences.

Holistic Approach to Energy Efficient Smart Green Buildings

( Essam E Khalil ),( F Asme ),( F Aiaa ),( F Ashrae ) 경남대학교 신소재연구소 2013 신소재연구 Vol.25 No.-

This review paper presents a recent status quo of HVAC airside design for the air-conditioned spaces under holistic approach for green and smart buildings. This briefly summarizes the current status, future requirements, and expectations. It has been found that, the experimental investigations should be considered in the new trend of energy investigations, not to merely to validate the numerical tools, but also to provide a complete database of the airflow characteristics in the air-conditioned spaces. Based on this analysis and the vast progress of computers and associated software, the artificial intelligent technique is sought as a prominent competitor candidate to the experimental and numerical techniques. Finally, the researches that relate between the different designs of the HVAC systems and energy consumption should concern with the optimization of airside design as the expected target to enhance the indoor environment.

Morningside Pi2 Pulsation Observed in Space and on the Ground

Essam Ghamry 한국우주과학회 2015 Journal of Astronomy and Space Sciences Vol.32 No.4

In this study, we examined a morningside Pi2 pulsation, with a non-substorm signature, that occurred in very quiet geomagnetic conditions (Kp = 0) at 05:38 UT on December 8, 2012, using data obtained by Van Allen Probes A and B (VAP-A and VAP-B, respectively) and at a ground station. Using 1 sec resolution vector magnetic field data, we measured the X-component of the pulsation from the Abu Simbel ground station (L = 1.07, LT = UT +2 hr, where LT represents local time) in Egypt. At the time of the Pi2 event, Abu Simbel and VAP-A (L = 3.3) were in the morning sector (07:38 LT and 07:59 MLT, respectively, where MLT represents magnetic local time), and VAP-B was in the postmidnight sector (04:18 MLT and L = 5.7). VAP-A and VAP-B observed oscillations in the compressional magnetic field component (Bz), which were in close agreement with the X-component measurements of the Pi2 pulsation that were made at Abu Simbel. The oscillations observed by the satellites and on the ground were in phase. Thus, we concluded that the observed morningside Pi2 pulsation was caused by the cavity resonance mode rather than by ionospheric current systems.

How many number of retrieved lymph nodes is required for accurate N-staging in resected pancreatic cancer?

Essam Dhafer ALHOTHAIFI,Ho Kyoung HWANG,Munseok CHOI,Chang Moo KANG,Woo Jung LEE 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-