mohamed abed - Academia.edu (original) (raw)

Papers by mohamed abed

Tikrit Journal of Engineering Sciences

An industrial scale falling film reactor (FFR) using gaseous SO3/ liquid Alkylbenzene as operatin... more An industrial scale falling film reactor (FFR) using gaseous SO3/ liquid Alkylbenzene as operating system- is analyzed for multiplicity and stability. The analysis has shown that up to 5 steady state solutions may exist. The existence of a highly multiplicity states is explained by the coupling between absorption and reaction. The system kinetic parameters have found to play an effective role on the stability behavior. An analytic solution is found for a special case of the liquid reactant in excess, this solution is performed by using eigen analysis. A mathematical procedure is also introduced to estimate the bifurcation points.

Journal of Building Pathology and Rehabilitation

Natural Hazards and Earth System Sciences

This study uses interferometric synthetic aperture radar (SAR) techniques to identify and track e... more This study uses interferometric synthetic aperture radar (SAR) techniques to identify and track earthquakeinduced landslides as well as lands prone to landslides, by detecting deformations in areas struck by earthquakes. The pilot study area investigates the Mila region in Algeria, which suffered significant landslides and structural damage (earthquake: M w 5, 7 August 2020). DInSAR analysis shows normal interferograms with small fringes. The coherence change detection (CCD) and DInSAR analysis were able to identify many landslides and ground deformations also confirmed by Sentinel-2 optical images and field inspection. The most important displacement (2.5 m), located in the Kherba neighborhood, caused severe damage to dwellings. It is worth notice that CCD and DInSAR are very useful since they were also able to identify ground cracks surrounding a large zone (3.94 km 2 area) in Grarem City, whereas the Sentinel-2 optical images could not detect them. Although displacement time-series analysis of 224 interferograms (April 2015 to September 2020) performed using LiCSBAS did not detect any pre-event geotechnical precursors, the post-event analysis shows a 110 mm yr −1 subsidence velocity in the back hillside of Kherba.

Egyptian Journal of Agricultural Research, Mar 1, 2013

Physiological and histochemical studies were conducted on Monacha cartusiana snail, in order to d... more Physiological and histochemical studies were conducted on Monacha cartusiana snail, in order to determine some physiological and histochemical aspects during active and aestivation periods. Results of these studies showed reduction of the percentage of glucose in aestivation periods compared with the period of activity, where the concentration of glucose in the activity revealed 52.63 mg / dL, compared with an average concentration in aestivation, reaching 16.16 mg / dL. Regarding the concentration of protein, it observed a decrease in aestivation period compared with activity period, where it reached 3.39 g / dL in the activity period compared with 1.9 g / dL in aestivation. In case of urea the opposite results were recorded, where the urea concentration in the period of activity was 5.97 mg / dL compared with 7.89 mg / dL in aestivation. The results of histochemical studies indicated the presence of large amounts of carbohydrates in the cells of the digestive gland as well as in the cells of foot in the previous of aestivation. Moreover the study showed that the snail consumed large amounts of carbohydrates during aestivation period.

The first impression a guest receives of a lodging facility during registration is extremely impo... more The first impression a guest receives of a lodging facility during registration is extremely important in setting the quality for hospitality and establishing a continuing business relationship. Today's guest expects to be treated with respect and concern, and many hotels make the effort to meet those expectations. Those who do not, should not expect the guest to return. Guest registration is nothing but recording the guest's information for official purposes. At the time of reservation, the front office staff asks the guests to enter their personal information on the GRC. Registration activity is mandatory for both the guest with reserved accommodation as well as for the walk-in guest. Guest registration modules have greatly improved the check-in process. Because information has already been captured at the time of reservation, less time is required for registration. The front desk clerk needs only to confirm the guest's pre-information and finally the guest request for...

ENP Engineering Science Journal, 2021

From structural and material point of view each historic monument is a textbook case, as it diffe... more From structural and material point of view each historic monument is a textbook case, as it differs in shape, age, material characteristics and level of preservation. New means and approaches are used for geometric and shape survey, material and modal characterization, which helps restitute detailed information regarding the structural elements of the edifices. This paper investigates a 1000 years old historic minaret having a square base of 6.50 m of side and 24.70 m height. An ambient vibration survey has been carried out and the results were used to update a Finite Element (FE) model of the minaret in two stages. First, the elastic modulus of the rubble stone masonry has been determined by matching the experimental and numerical fundamental frequency. In a second phase, a frequency response function (FRF) correlation is carried out iteratively by adjusting the damping ratios to minimize the FRF error. The elastic modulus of the rubble stone masonry is found to be in the lowest ra...

The design of a new base isolation system is proposed in this research with the objective that th... more The design of a new base isolation system is proposed in this research with the objective that the system does not transmit any force to the structure under horizontal loading. The structure must remain operational and steady. Before investigating the dynamics problem of the base isolation system, the isolator components of the model can be solved analytically using different approaches. In order to calculate the deformation of any element of the isolator due to a compressive vertical load, the analysis focuses on the primary instability region to determine all deformations parameters which can lead to frictions coefficients. This region is located at the interaction contact point between the elements. The design is based on the contact point developed by different approaches. In the present study, the mathematical analysis methods by using formulations can calculate the different dimensions and deformations of the elements of the system and which are verified using ANSYS finite ele...

Topics in Middle Eastern andNorth African Economies, 2018

This research seeks to empirically examine the impact of Foreign Direct Investment )FDI( on real ... more This research seeks to empirically examine the impact of Foreign Direct Investment )FDI( on real wages in Egypt. First, we test the effect of FDI on real wages on the whole economy, and then special attention is given to the basic sectors in the economy. For this purpose, we make use of time-series Autoregressive Distributed Lag (ARDL) models utilizing annual data covering the period 1985-2014. Our results reveal that FDI positively affects the average wages in the long-run in almost all conducted models. According to the sectoral models, the highest long-run effect of FDI on wages is detected in the manufacturing sector, while it is insignificant in the tourism sector. Attracting more FDI in general and manufacturing FDI in particular is recommended as this will have a positive effect on average wages and consequently raise the economy’s output and overall income. JEL Codes:E22, E24, F21 1 Assistant Lecturer, Damanhour University, Egypt. 2 Associate Professor, Alexandria University...

More than 2,000 years ago, Mary and Najjar fled with Jesus to Egypt in order to escape the wrath ... more More than 2,000 years ago, Mary and Najjar fled with Jesus to Egypt in order to escape the wrath of King Herod. This was a defining moment in the history of the Coptic Christians, for Egypt became a second Holy Land when their own land was blessed by the presence of the Holy Family. At present, many Egyptian historians and archeologists are calling for a project to track each town or city visited by the holy family. In anticipation of pilgrims, Egypt is working to restore several holy sites. Vatican Pope visited Egypt in April 2017. The designation of Egypt as a pilgrimage site was endorsed by Vatican Pope in October during his general audience, where he recognizes Egypt as an Official Pilgrim site. This program is forecasted to attract a large number of tourists from all around the world. This study aims at reviveing the historical places of the journey of the holy family in Egypt by determining the main barriers that may face travellers during their visit and the possibility of de...

Journal of Association of Arab Universities for Tourism and Hospitality, 2021

Blue Collar Technicians play a vital role in the success of any Hospitality Business, in other wo... more Blue Collar Technicians play a vital role in the success of any Hospitality Business, in other words it plays the role of the hidden soldier. This segment of hospitality workers was severely affected by the successive crises during the recent years. Unfortunately, the recent crises led to many sharp fluctuations in the volume of business which obliged many workers to leave their job in the hospitality sector to other irrelevant jobs, that is not related to this important sector. This study sheds the light on the problem of labor random layoffs from the hospitality properties due to successive crisis and fluctuations of business in recent years and its effect on an important employee segment which is Blue Collar/hospitality technician and monitor its effect on the immigration to other working sectors. Design/methodology/approach-the data were collected via a semi structured questionnaire addressed to experts in tourism and hospitality fields and another questionnaire addressed to a sample of Blue Collar/technician in the hospitality sector. Research limitations/implications-The research focused on five and four-star resorts in Marsa Allam Red Sea area. 1. Introduction Dealing with crisis in the hospitality industry was an issue that has been handled in many ways and different perspectives by hoteliers, hospitality experts and academics. Crisis to the hospitality organizations has many shapes; above all became the political instability and terrorism that could face any region (El-Sayed and Hammam, 2017; Breier et al., 2021), financial crisis either on the limited scale (in a certain region) or on the large scale (that includes many countries) or natural crises (Breier et al., 2021). Experts in hospitality field offered many ideas and solutions to overcome crisis that may face hospitality operations as; designing new products and services, reshaping the marketing efforts, targeting new tourism destinations, targeting the local market with new offers and packages or call for governmental support (El-Sayed and Hammam, 2017). Breier et al. (2021) added that to survive during a crisis it is important to extend the period for local payments and taxes. In addition; hospitality operation companies

This study uses interferometric SAR techniques to identify landslides and lands prone to landslid... more This study uses interferometric SAR techniques to identify landslides and lands prone to landslides, detect fringes and changes in areas struck by earthquakes. The pilot study investigates the Mila region (Algeria) which suffered significant landslides and structural damages (earthquake: Mw 5, 2020-08-07): the study checks ground deformations and tracks earthquake-induced landslides. DInSAR analysis shows normal interferograms, with atmospheric contribution, and slight fringes. However, it identifies many landslides, the most important (2.5 m displacement) being located in Kherba neighborhood, causing severe damages to dwellings. In addition, SAR images and optical images (Sentinel-2) confirm site investigations. Although in Grarem City, optical images could not detect any disorder, the DInSAR analysis detected some coherence decays and small fringes (3.94 Km 2 area). These unnoticed ground disorders were confirmed during fields inspection. Such results have key importance since they can serve as an alert to monitor the zone at the proper time. Furthermore, Displacement time series analysis of many interferograms (April 2015 to September 2020) using LiCSBAS were performed to investigate the pre-event conditions and precursors of the slopes instabilities., LiCSBAS detects a line-of-sight subsidence velocity of-110 mm/y in the back hillside of Kherba, and high displacement velocity at specific points in Grarem region. 1 Introduction Although it is still challenging to predict exactly where and when natural hazards (earthquakes, landslides, floods, etc.) might occur, the capacity to monitor and survey the zones prone to important landslides as well as the capacity to identify and locate those impacted by earthquakes are key issues in risks mitigation, reduction, preparedness and adaptation. Actually, since earthquakes and landslides might occur in many places worldwide, they might cause a huge number of victims, important socioeconomic , assets damages and losses. Their impact can be significantly reduced thanks to satellite imaging which allows prediction and early alerts of some landslide cases (Jacquemart and Tiampo, 2021). It is then worth detecting or predicting critical ground changes at specific places, either after a geotechnical disorder occurs due to landslides and earthquakes mainly, or before it is suddenly triggered (Bakon et al., 2014; Galve et al., 2015). Such challenges can be tackled by regular image processing oriented landslides areas monitoring, in the aftermath of earthquakes, by means of SAR interferometric methods and optical images, for instance. Actually, since InSAR (Interferometric Synthetic Aperture Radar) is an active sensor system that uses microwave signals to collect data backscattered from the earth's surface,

Journal of Association of Arab Universities for Tourism and Hospitality, 2020

Purpose-Word of mouth (WOM) is considered among the most powerful source of information that affe... more Purpose-Word of mouth (WOM) is considered among the most powerful source of information that affect consumers' purchasing decisions in the hotel industry. The importance of this effect growing because of the hospitality nature, those services are difficult to evaluate before consumption. The digitization of WOM and its spread on a large scale make it easier to track opinions about the services offered, which is more likely to have more credibility among consumers. Handling and responding to guest comments and reviews especially negative one is a very important in affecting the purchasing decision of the potential consumers. The purpose of this study is to investigate how managing customers' online reviews affect hotel performance and customers retention of some four stars hotels in Red Sea, Egypt. Design/methodology/approach-the data was collected through a semi-structured interview addressed to Director of Sales and Marketing and another questionnaire addressed to a sample of customers who lately visited the Red Sea. Research limitations/implications-The research focused on a sample of the four stars resort hotel's in Red Sea, Egypt.

Journal of World's Poultry Research, Mar 25, 2020

Bacterial oligodeoxynucleotide containing Cytosine Guanine motifs (CpG-ODN) has been reported to ... more Bacterial oligodeoxynucleotide containing Cytosine Guanine motifs (CpG-ODN) has been reported to induce immunostimulatory activity against a variety of bacterial, viral, and protozoan infections in a wide range of vertebrate species. The objective of this study was to investigate the dose-dependent immunomodulatory effect of CpG ODN on Salmonella Enteritidis bacterin in broiler chickens. Two hundreds one-day-old broiler chicks, divided into 5 groups, were used in this study. First three groups were immunized with Salmonella Enteritidis bacterin adjuvanted with different doses of CpG ODN (50µg, 100µg and 200µg). The control groups included a group that was immunized with Salmonella Enteritidis bacterin adjuvanted with aluminum hydroxide and a non-immunized group. The intestinal colonization, cellular responses, mucosal and systemic immune responses of immunized chickens was measured at different intervals, until 42 days of age. At two weeks post-immunization, 20 chicks from each group were orally challenged by Salmonella Enteritidis fresh bacterial culture (1.2x10 8 CFU/ml). The survival rates and the pathological changes of challenged chickens in the different groups were monitored for extra 10 days. Compared to the aluminum hydroxide adjuvanted bacterin, the CpG-ODN adjuvant bacterin induced significant protection and improved survival rate of challenged chickens. Also Salmonella Enteritidis was not recovered from the intestinal tract of vaccinated challenged groups. There was a significant dose-dependent immunostimulatory adjuvant effect of CPG-ODN on the level of secretory IgA and the induced mucosal responses. The 200-CpG ODN group showed the highest IgA response followed by 100-CpG ODN group then the 50-CpG ODN and the aluminum hydroxide groups (P < 0.05). Also, cellular interactions were remarkably reduced in the liver and intestine of CpG ODN-treated chickens. No inflammatory cellular infiltrations were seen in the liver and intestine of 200-CpG ODN treated group. In conclusion, the presented findings have shown the significant immunostimulatory effect of CpG-ODN and its effect on Salmonella Enteritidis bacterin in controlling Salmonella infection in broiler chickens.

Journal of Association of Arab Universities for Tourism and Hospitality, 2018

PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON BIOSCIENCES AND MEDICAL ENGINEERING (ICBME2019): Towards innovative research and cross-disciplinary collaborations, 2019

The aim of this study is to evaluate the efficacy of some biological control agents in the resist... more The aim of this study is to evaluate the efficacy of some biological control agents in the resistance of Trichoderma harzianium, Trichoderma viride and mycorrhizal fungi Glomus mosseae, individually or collectively, Fusarim oxysporum f.sp. cucumerinum. The results of this study showed that the combined biological control factors had a positive and significant effect in reducing the severity of injury of the disease by 20% and 21% respectively, with an effect efficiency of 73.92% and 65.30% in reducing the percent of the injury severity. Followed by the treatment of mycorrhizal fungi G. mosseae, the results showed a reduction of injury severity with 26.7%, 23% and 65.18%, 62.47%. The use of T.harzianium and T. viride has also resulted in a significant reduction of the injury severity by 43.3%, 23%, 46.7%, 29.3%, 46.7% and 23%, respectively. In addition, the use of these biological control agents had a significant impact on the growth. An increase in the plant height, leaves number, wet and dry weight of plant was also observed.

Engineering Structures, 2018

The present paper develops a methodology based on fuzzy logic for post-earthquake assessment of b... more The present paper develops a methodology based on fuzzy logic for post-earthquake assessment of buildings damage. It derives the global building damage level from that reported information by trained technical staff, after in-situ visual inspection of the main parameters, i.e., the "Structural components" and the "Non-structural components". For illustration purposes, thousands of evaluation forms from post-earthquake survey following the 2003 Boumerdes, Algeria, earthquake (Mw = 6.8) have been collected. According to the standard evaluation form, each component's damage is ranked from D 1 (No damage) up to D 5 (Collapse). The aim is then to derive the global damage level of buildings which should also rank from D 1 to D 5. The paper investigates the effect of the number and weights of fuzzy rules to relate each components' damage level to the global damage level using a single-antecedent weighted fuzzy rule. It investigates also the effect of membership functions values so that it is possible to consider one damage level as the most dominant with highest membership value whereas the rest damage levels are still considered although with lower influence. A genetic algorithm is adopted to optimize the rule weights associated to the components' damage levels. The collected database which covers more than 27,000 buildings is used to train and validate the procedure. The theoretical prediction, obtained by automatic processing of the evaluation form for each building, is compared to the global damage (observed damage) identified by inspectors. Results show that the theoretically-based evaluation is in accordance with the observed values for 90% of the investigated buildings.