Search results for: Mohamed Ahmed M. Azab
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2883

Search results for: Mohamed Ahmed M. Azab

2073 Photocatalytic Conversion of Water/Methanol Mixture into Hydrogen Using Cerium/Iron Oxides Based Structures

Authors: Wael A. Aboutaleb, Ahmed M. A. El Naggar, Heba M. Gobara

Abstract:

This research work reports the photocatalytic production of hydrogen from water-methanol mixture using three different 15% ceria/iron oxide catalysts. The catalysts were prepared by physical mixing, precipitation, and ultrasonication methods and labeled as catalysts A-C. The structural and texture properties of the obtained catalysts were confirmed by X-ray diffraction (XRD), BET-surface area analysis and transmission electron microscopy (TEM). The photocatalytic activity of the three catalysts towards hydrogen generation was then tested. Promising hydrogen productivity was obtained by the three catalysts however different gases compositions were obtained by each type of catalyst. Specifically, catalyst A had produced hydrogen mixed with CO₂ while the composite structure (catalyst B) had generated only pure H₂. In the case of catalyst C, syngas made of H₂ and CO was revealed, as a novel product, for the first time, in such process.

Keywords: hydrogen production, water splitting, photocatalysts, clean energy

Procedia PDF Downloads 220
2072 Experimental Study of a Solar Still with Four Glass Cover

Authors: Zakaria Haddad, Azzedine Nahoui, Mohamed Salmi, Ali Djagham

Abstract:

Solar distillation is an effective and practical method for the production of drinking water in arid and semi-arid areas; however, this production is very limited. The aim of this work is to increase the latter by means of single slope solar still with four glass cover without augmenting volume and surface of a conventional solar still, using local materials and simple design. The equipment was tested under the climatic condition of Msila city (35°70′ N, 4°54′ E), Algeria. Performance of the use of four glass cover was studied, and exhaustive data were collected, analyzed, and presented. To show the effectiveness of the system, its performance was compared with that of the conventional solar still. The experimental study shows that the production of the proposed system achieves 5.3 l/m²/day and 5.8 l/m²/day respectively for the months of April and May, with an increase of 10% and 17% compared to the conventional solar still.

Keywords: drinking water, four glass cover, production, solar distillation

Procedia PDF Downloads 115
2071 Study of Some Aromatic Thiourea Derivatives as Lube Oil Antioxidant

Authors: Rasha S. Kamal, Nehal S. Ahmed, Amal M. Nassar, Nour E. A. Abd El-Sattar

Abstract:

In the present work, some lube oil antioxidants based on ester of some aromatic thiourea derivative were prepared by two steps: the first step is the reaction of succinyl chloride with ammonium thiocyanate in addition to anthranilic acid as three component system to prepare thiourea derivative (A); the second step is esterification of compound (A) by different alcohol (decyl C₁₀, tetradecyl C₁₄, and octadecyl C₁₈) alcohol. The structures of the prepared compounds were confirmed by infra-red spectroscopy, nuclear magnetic resonance, elemental analysis and determination of the molecular weights. All the prepared compounds were soluble in lube oil. The efficiency of the prepared compounds as antioxidants lube oil additives was investigated and it was found that these prepared compounds give good result as lube oil antioxidant.

Keywords: antioxidant lube oil, three component system, aromatic thiourea derivatives, esterification

Procedia PDF Downloads 222
2070 Temporally Coherent 3D Animation Reconstruction from RGB-D Video Data

Authors: Salam Khalifa, Naveed Ahmed

Abstract:

We present a new method to reconstruct a temporally coherent 3D animation from single or multi-view RGB-D video data using unbiased feature point sampling. Given RGB-D video data, in form of a 3D point cloud sequence, our method first extracts feature points using both color and depth information. In the subsequent steps, these feature points are used to match two 3D point clouds in consecutive frames independent of their resolution. Our new motion vectors based dynamic alignment method then fully reconstruct a spatio-temporally coherent 3D animation. We perform extensive quantitative validation using novel error functions to analyze the results. We show that despite the limiting factors of temporal and spatial noise associated to RGB-D data, it is possible to extract temporal coherence to faithfully reconstruct a temporally coherent 3D animation from RGB-D video data.

Keywords: 3D video, 3D animation, RGB-D video, temporally coherent 3D animation

Procedia PDF Downloads 351
2069 Zero Cross-Correlation Codes Based on Balanced Incomplete Block Design: Performance Analysis and Applications

Authors: Garadi Ahmed, Boubakar S. Bouazza

Abstract:

The Zero Cross-Correlation (C, w) code is a family of binary sequences of length C and constant Hamming-weight, the cross correlation between any two sequences equal zero. In this paper, we evaluate the performance of ZCC code based on Balanced Incomplete Block Design (BIBD) for Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA) system using direct detection. The BER obtained is better than 10-9 for five simultaneous users.

Keywords: spectral amplitude coding-optical code-division-multiple-access (SAC-OCDMA), phase induced intensity noise (PIIN), balanced incomplete block design (BIBD), zero cross-correlation (ZCC)

Procedia PDF Downloads 346
2068 Evaluation of Biomass Introduction Methods in Coal Co-Gasification

Authors: Ruwaida Abdul Rasid, Kevin J. Hughes, Peter J. Henggs, Mohamed Pourkashanian

Abstract:

Heightened concerns over the amount of carbon emitted from coal-related processes are generating shifts to the application of biomass. In co-gasification, where coal is gasified along with biomass, the biomass may be fed together with coal (co-feeding) or an independent biomass gasifier needs to be integrated with the coal gasifier. The main aim of this work is to evaluate the biomass introduction methods in coal co-gasification. This includes the evaluation of biomass concentration input (B0 to B100) and its gasification performance. A process model is developed and simulated in Aspen HYSYS, where both coal and biomass are modeled according to its ultimate analysis. It was found that the syngas produced increased with increasing biomass content for both co-feeding and independent schemes. However, the heating values and heat duties decreases with biomass concentration as more CO2 are produced from complete combustion.

Keywords: aspen HYSYS, biomass, coal, co-gasification modelling, simulation

Procedia PDF Downloads 388
2067 The Synergistic Effects of Using Silicon and Selenium on Fruiting of Zaghloul Date Palm (Phoenix dectylifera L.)

Authors: M. R. Gad El- Kareem, A. M. K. Abdel Aal, A. Y. Mohamed

Abstract:

During 2011 and 2012 seasons, Zaghloul date palms received four sprays of silicon (Si) at 0.05 to 0.1% and selenium (Se) at 0.01 to 0.02%. Growths, nutritional status, yield as well as physical and chemical characteristics of the fruits in response to application of silicon and selenium were investigated. Single and combined applications of silicon at 0.05 to 0.1% and selenium at 0.01 to 0.02% was very effective in enhancing the leaf area, total chlorophylls, percentages of N, P, and K in the leaves, yield, bunch weight as well as physical and chemical characteristics of the fruits in relative to the check treatment. Silicon was superior to selenium in this respect. Combined application was favourable than using each alone in this connection. Treating Zaghloul date palms four times with a mixture of silicon at 0.05% + selenium at 0.01% resulted in an economical yield and producing better fruit quality.

Keywords: date palms, Zaghloul, silicon, selenium, leaf area

Procedia PDF Downloads 363
2066 Remembering Route in an Unfamiliar Homogenous Environment

Authors: Ahmed Sameer, Braj Bhushan

Abstract:

The objective of our study was to compare two techniques (no landmark vs imaginary landmark) of remembering route while traversing in an unfamiliar homogenous environment. We used two videos each having nine identical turns with no landmarks. In the first video participant was required to remember the sequence of turns. In the second video participant was required to imagine a landmark at each turn and associate the turn with it. In both the task the participant was asked to recall the sequence of turns as it appeared in the video. Results showed that performance in the first condition i.e. without use of landmarks was better than imaginary landmark condition. The difference, however, became significant when the participant were tested again about 30 minutes later though performance was still better in no-landmark condition. The finding is surprising given the past research in memory and is explained in terms of cognitive factors such as mental workload.

Keywords: wayfinding, landmarks, unfamiliar environment, cognitive psychology

Procedia PDF Downloads 453
2065 Graphene-Oxide-Supported Coal-Layered Double Hydroxides: Synthesis and Characterizations

Authors: Shaeel A. Al Thabaiti, Sulaiman N. Basahel, Salem M. Bawaked, Mohamed Mokhtar

Abstract:

Nanosheets for cobalt-layered double hydroxide (Co-Al-LDH)/GO were successfully synthesized with different Co:M g:Al ratios (0:3:1, 1.5:1.5:1, and 3:0:1). The layered double hydroxide structure and morphology were determined using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Temperature prgrammed reduction (TPR) of Co-Al-LDH showed reduction peaks at lower temperature which indicates the ease reducibility of this particular sample. The thermal behaviour was studied using thermal graviemetric technique (TG), and the BET-surface area was determined using N2 physisorption at -196°C. The C-C coupling reaction was carried out over all the investigated catalysts. The Mg–Al LDH catalyst without Co ions is inactive, but the isomorphic substitution of Mg by Co ions (Co:Mg:Al = 1.5:1.5:1) in the cationic sheet resulted in 88% conversion of iodobenzene under reflux. LDH/GO hybrid is up to 2 times higher activity than for the unsupported LDH.

Keywords: adsorption, co-precipitation, graphene oxide, layer double hydroxide

Procedia PDF Downloads 279
2064 Secure Proxy Signature Based on Factoring and Discrete Logarithm

Authors: H. El-Kamchouchi, Heba Gaber, Fatma Ahmed, Dalia H. El-Kamchouchi

Abstract:

A digital signature is an electronic signature form used by an original signer to sign a specific document. When the original signer is not in his office or when he/she travels outside, he/she delegates his signing capability to a proxy signer and then the proxy signer generates a signing message on behalf of the original signer. The two parties must be able to authenticate one another and agree on a secret encryption key, in order to communicate securely over an unreliable public network. Authenticated key agreement protocols have an important role in building a secure communications network between the two parties. In this paper, we present a secure proxy signature scheme over an efficient and secure authenticated key agreement protocol based on factoring and discrete logarithm problem.

Keywords: discrete logarithm, factoring, proxy signature, key agreement

Procedia PDF Downloads 285
2063 Enhanced Bit Error Rate in Visible Light Communication: A New LED Hexagonal Array Distribution

Authors: Karim Matter, Heba Fayed, Ahmed Abd-Elaziz, Moustafa Hussein

Abstract:

Due to the exponential growth of mobile devices and wireless services, a huge demand for radiofrequency has increased. The presence of several frequencies causes interference between cells, which must be minimized to get the lower Bit Error Rate (BER). For this reason, it is of great interest to use visible light communication (VLC). This paper suggests a VLC system that decreases the BER by applying a new LED distribution with a hexagonal shape using a Frequency Reuse (FR) concept to mitigate the interference between the reused frequencies inside the hexagonal shape. The BER is measured in two scenarios, Line of Sight (LoS) and Non-Line of Sight (Non-LoS), for each technique that we used. The recommended values of BER in the proposed model for Soft Frequency Reuse (SFR) in the case of Los at 4, 8, and 10 dB signal to noise ratio (SNR), are 3.6×10⁻⁶, 6.03×10⁻¹³, and 2.66×10⁻¹⁸, respectively.

Keywords: visible light communication (VLC), field of view (FoV), hexagonal array, frequency reuse

Procedia PDF Downloads 143
2062 The Dialectic of Law and Politics for George Friedrich Wilhelm Hegel

Authors: Djehich Mohamed Yousri

Abstract:

This paper aims to address the dialectic of law and politics in the philosophy of the state of the philosopher Hegel by addressing the concept of law, which refers to its general meaning to the set of rules and legislation that man sets to apply them within society, as it is considered one of the primary and necessary conditions for the functioning of And organizing social life, when it defines the rights and duties of every individual belonging to the state, by approaching it with central concepts in political philosophy, such as the state, freedom and the people. The most prominent result that we reached through our analysis of the details of the problematic research is the relationship between law and politics in the philosophical system of Hegel; on the one hand, We find that the state is rational only to the extent that it resorts to the law and works under it, and the latter does not realize its essence and effectiveness unless it is extracted from the customs, traditions, and culture of the people so that it does not conflict with the ideal goal of its existence, which is to achieve freedom and protect it from all possible. A state does not mean at all to reduce the freedom of the people, so there is no conflict between law and freedom.

Keywords: hegel, the law, country, freedom, citizen

Procedia PDF Downloads 64
2061 Structural, Optical and Electrical Properties of PbS Thin Films Deposited by CBD at Different Bath pH

Authors: Lynda Beddek, Nadhir Attaf, Mohamed Salah Aida

Abstract:

PbS thin films were grown on glass substrates by chemical bath deposition (CBD). The precursor aqueous bath contained 1 mole of lead nitrate, 1 mole of Thiourea and complexing agents (triethanolamine (TEA) and NaOH). Bath temperature and deposition time were fixed at 60°C and 3 hours, respectively. However, the PH of bath was varied from 10.5 to 12.5. Structural properties of the deposited films were characterized by X-ray diffraction and Raman spectroscopy. The preferred direction was revealed to be along (111) and the PbS crystal structure was confirmed. Strains and grains sizes were also calculated. Optical studies showed that films thicknesses do not exceed 600nm. Energy band gap values of films decreases with increase in pH and reached a value ~ 0.4eV at pH equal 12.5. The small value of the energy band gap makes PbS one of the most interesting candidate for solar energy conversion near the infrared ray.

Keywords: CBD, PbS, pH, thin films, x-ray diffraction

Procedia PDF Downloads 420
2060 The Mitidja between Drought and Water Pollution

Authors: Aziez Ouahiba, Remini Boualam, Habi Mohamed

Abstract:

the growth and the development of a pay are strongly related to the existence or the absence of water in this area, The sedentary lifestyle of the population makes that water demand is increasing and the different brandishing (dams, tablecloths or other) are increasingly solicited. In normal time rain and snow of the winter period reloads the slicks and the wadis that fill dams. Over these two decades, global warming fact that temperature is increasingly high and rainfall is increasingly low which induces a charge less and less important tablecloths, add to that the strong demand in irrigation. Our study will focus on the variation of rainfall and irrigation, their effects on the degree of pollution of the groundwater in this area based on statistical analyses by the Xlstat (ACP, correlation...) software for a better explanation of these results and determine the hydrochemistry of different groups or polluted areas pou be able to offer adequate solutions for each area.

Keywords: rainfall, groundwater of mitidja, irrigation, pollution

Procedia PDF Downloads 386
2059 Estimation of Enantioresolution of Multiple Stereogenic Drugs Using Mobilized and/or Immobilized Polysaccharide-Based HPLC Chiral Stationary Phases

Authors: Mohamed Hefnawy, Abdulrahman Al-Majed, Aymen Al-Suwailem

Abstract:

Enantioseparation of drugs with multiple stereogenic centers is challenging. This study objectives to evaluate the efficiency of different mobilized and/or immobilized polysaccharide-based chiral stationary phases to separate enantiomers of some drugs containing multiple stereogenic centers namely indenolol, nadolol, labetalol. The critical mobile phase variables (composition of organic solvents, acid/base ratios) were carefully studied to compare the retention time and elution order of all isomers. Different chromatographic parameters such as capacity factor (k), selectivity (α) and resolution (Rs) were calculated. Experimental conditions and the possible chiral recognition mechanisms have been discussed.

Keywords: HPLC, polysaccharide columns, enantio-resolution, indenolol, nadolol, labetalol

Procedia PDF Downloads 428
2058 Fabrication of Eco-Friendly Pigment Printed Textiles by Reducing Formaldehyde Content

Authors: Sidra Saleemi, Raja Fahad Qureshi, Farooq Ahmed, Rabia Almas, Tahir Jameel

Abstract:

This research aimed to decrease formaldehyde content in substrates printed by pigments using different fixation temperature and concentration of urea in order to produce eco-friendly textiles. Substrates were printed by hand screen printing method as per recipe followed by drying and curing. Standard test methods were adapted to measure formaldehyde content washing and rubbing fastness. Formaldehyde content is instantaneously decreased by raising the temperature during curing printed fabric. Good results of both dry and wet rubbing fastness were found at 160˚C slightly improved dry rubbing results are achieved with 2% urea at a curing temperature of 150˚C.

Keywords: formaldehyde content, pigment printing, urea, washing fastness, rubbing fastness

Procedia PDF Downloads 289
2057 Airport Check-In Optimization by IP and Simulation in Combination

Authors: Ahmed Al-Sultan

Abstract:

The check-in area of airport terminal is one of the busiest sections at airports at certain periods. The passengers are subjected to queues and delays during the check-in process. These delays and queues are due to constraints in the capacity of service facilities. In this project, the airport terminal is decomposed into several check-in areas. The airport check-in scheduling problem requires both a deterministic (integer programming) and stochastic (simulation) approach. Integer programming formulations are provided to minimize the total number of counters in each check-in area under the realistic constraint that counters for one and the same flight should be adjacent and the desired number of counters remaining in each area should be fixed during check-in operations. By using simulation, the airport system can be modeled to study the effects of various parameters such as number of passengers on a flight and check-in counter opening and closing time.

Keywords: airport terminal, integer programming, scheduling, simulation

Procedia PDF Downloads 372
2056 Juvenile Paget’s Disease(JPD) of Bone

Authors: Aftab Ahmed, Ghulam Mehboob

Abstract:

The object of presentation is to highlight the importance of condition which is a very rare genetic disorder although Paget’s disease is common but its juvenile type is very rare and a late presentation due to very slow onset and lack of earlier standard management. We present a case of 25 years old male with a chronic history of bone pain and a slow onset of mild swelling, later on diagnosed as juvenile Paget disease of bone. Rarity of this condition with inaccessibility for standard health treatment can lead to a significant delay in presentation and its management. There have been 50 reported cases worldwide according to Genetic Home Reference. There is increased osteoclastic activity along with osteoblastic activity related to gene alteration and osteoprotegrin deficiency. Morbidity of disease is very significant which lead children to become immobilize.

Keywords: juvenile, Paget’s disease, bone, Northern Area of Pakistan

Procedia PDF Downloads 307
2055 The Effect of Geogrid Reinforcement Pre-Stressing on the Performance of Sand Bed Supporting a Strip Foundation

Authors: Ahmed M. Eltohamy

Abstract:

In this paper, an experimental and numerical study was adopted to investigate the effect geogrid soil reinforcement pre-stressing on the pressure settlement relation of sand bed supporting a strip foundation. The studied parameters include foundation depth and pre-stress ratio for the cases of one and two pre-stressed reinforcement layers. The study reflected that pre-stressing of soil reinforcement resulted in a marked enhancement in reinforced bed soil stiffness compared to the reinforced soil without pre-stress. The best benefit of pre-stressing reinforcement was obtained as the overburden pressure and pre-straining ratio increase. Pre-stressing of double reinforcement topmost layers results in further enhancement of stress strain relation of bed soil.

Keywords: geogrid reinforcement, prestress, strip footing, bearing capacity

Procedia PDF Downloads 285
2054 Securing Land Rights for Food Security in Africa: An Appraisal of Links Between Smallholders’ Land Rights and the Right to Adequate Food in Ethiopia

Authors: Husen Ahmed Tura

Abstract:

There are strong links between secure land rights and food security in Africa. However, as land is owned by governments, land users do not have adequate legislative protection. This article explores normative and implementation gaps in relation to small-scale farmers’ land rights under the Ethiopia’s law. It finds that the law facilitates eviction of small-scale farmers and indigenous peoples from their land without adequate alternative means of livelihood. It argues that as access to land and other natural resources is strongly linked to the right to adequate food, Ethiopia should reform its land laws in the light of its legal obligations under international human rights law to respect, protect and fulfill the right to adequate food and ensure freedom from hunger.

Keywords: smallholder, secure land rights , food security, right to food, land grabbing, forced evictions

Procedia PDF Downloads 286
2053 Study the Efficiency of Some Homopolymers as Lube Oil Additives

Authors: Amal M. Nassar, Nehal S. Ahmed, Rasha S. Kamal

Abstract:

Some lube oil additives improve the base oil performance such as viscosity index improvers and pour point depressants which are the most important type of additives. In the present work, some homopolymeric additives were prepared by esterification of acrylic acid with different alcohols (1-dodecyl, 1-hexadecyl, and 1-octadecyl )and then homopolymerization of the prepared esters with different ratio of benzoyl peroxide catalyst (0.25%& 0.5 % and 1%). Structure of the prepared esters was confirmed by Infra-Red Spectroscopy. The molecular weights of the prepared homopolymers were determined by using Gel Permeation Chromatograph. The efficiency of the prepared homopolymers as viscosity index improvers and pour point depressants for lube oil was the investigation. It was found that all the prepared homopolymers are effective as viscosity index improvers and pour point depressants.

Keywords: lube oil additives, homopolymerization, viscosity index improver, pour point depressant

Procedia PDF Downloads 207
2052 Employees’ Satisfaction and Engagement in UAE: Antecedents and Outcomes

Authors: Sareh Rajabi, Taha Anjamrooz, Ahmed Hassan Almarzooqi

Abstract:

Employee satisfaction, engagement, and performance are crucial for successful organizations. The performance of the employees now depends on their satisfaction level and whether they are satisfied with the management. Due to this fact, the organizations are now measuring the satisfaction level of their employees to increase profitability, productivity, and turnover. The aim of this research is to inspect the antecedents which direct in the direction of significant employee engagement and good job fit by finding the relationship between employee satisfaction and engagement. Based on an inclusive literature review on the employees’ satisfaction, engagement and performance, this research will conduct a study and survey in the UAE organizations in order to develop a framework for evaluating the impact of factors like employee satisfaction and engagement on the operation as an outcome by using statistical analysis. This study will allow in understanding the advantages of containing satisfied employees and how they perform in their peak motivation to make the company more profitable and competitive.

Keywords: employees’ satisfaction, employees’ engagement, antecedents, outcomes

Procedia PDF Downloads 136
2051 Antecedents and Consequences of Social Media Adoption in Travel and Tourism: Evidence from Customers and Industry

Authors: Mohamed A. Abou-Shouk, Mahamoud M. Hewedi

Abstract:

This study extends technology acceptance model (TAM) to investigate the antecedents and consequences of social media adoption by tourists and travel agents. It compares their perceptions on social media adoption and its consequences. Online survey was addressed to tourists and travel agents for data collection purposes. Structural equation modelling was employed for analysis purposes. The findings revealed that the majority of tourists and travel agents involved in the study believe in the usefulness of social media adoption for travel planning and marketing purposes. They agree that adopting social media could change the attitude of tourists towards specific destination or attraction and influence their purchasing decisions. This study contributes to knowledge by extending TAM and provides some managerial implication to marketers.

Keywords: TAM, social media, travel and tourism, travel agents

Procedia PDF Downloads 396
2050 The Fluid Limit of the Critical Processor Sharing Tandem Queue

Authors: Amal Ezzidani, Abdelghani Ben Tahar, Mohamed Hanini

Abstract:

A sequence of finite tandem queue is considered for this study. Each one has a single server, which operates under the egalitarian processor sharing discipline. External customers arrive at each queue according to a renewal input process and having a general service times distribution. Upon completing service, customers leave the current queue and enter to the next. Under mild assumptions, including critical data, we prove the existence and the uniqueness of the fluid solution. For asymptotic behavior, we provide necessary and sufficient conditions for the invariant state and the convergence to this invariant state. In the end, we establish the convergence of a correctly normalized state process to a fluid limit characterized by a system of algebraic and integral equations.

Keywords: fluid limit, fluid model, measure valued process, processor sharing, tandem queue

Procedia PDF Downloads 305
2049 Ethical Finance and Islamic Finance: Particularities, Possible Convergence and Potential Development

Authors: Safa Ougoujil, Sidi Mohamed Rigar

Abstract:

Economics is not an exact science. It cannot be from the moment it is a social science that concerns society organization, a human science that depends on the behavior of the men and women who make a part of this society. Therefore, it cannot ignore morality, the instinctive sense of good and evil, the natural order which place us between certain values, and which religion often sheds light on. In terms of finance, the reference to ethics is becoming more popular than ever. This is naturally due to the growing financial crises. Finance is less and less ethical, but some financial practices have continued to do so. This is the case of ethical finance and Islamic finance. After attempting to define the concepts of ethical finance and Islamic finance, in a period when financial innovation seeks to encourage differentiation in order to create more profit margins, this article attempts to expose the particularities, the convergences and the potentialities of development of these two sensibilities.

Keywords: convergences, ethical finance, Islamic finance, potential development

Procedia PDF Downloads 177
2048 DNA Intercalating Alkaloids Isolated from Chelidonium majus (Papaveraceae)

Authors: Mohamed Tamer, Wink Michael

Abstract:

DNA intercalating agents increase the stability of DNA which can be demonstrated by measuring the melting temperature Tm. Tm can be determined in a spectrophotometer in which the cell temperature is increased gradually. The resulting absorption data comes as a sigmoidal curve from which melting temperature can be determined when half of the DNA has denatured. The current study aims to assess DNA intercalating activities of four pure bioactive isoquinoline alkaloids: sanguinarine, berberine, allocryptopine, and chelerythrine which were isolated from Chelidonium majus (Papaveraceae) by repeated silica gel column chromatography, recrystallization and preparative TLC. The isolated compounds were identified by comparing their physical properties and mass spectra with those of the published data. The results showed that sanguiarine is the most active intercalating agent with Tm value of 83.55 ± 0.49 followed by berberine, chelerythrine, and allocryptopine with Tm values 62.58 ± 0.47, 51.38 ± 0.37 and 50.94 ± 0.65, respectively, relative to 49.78 ± 1.05 of bacteriophage DNA alone and 86.09 ± 0.5 for ethidium bromide as a positive control.

Keywords: alkaloids, Chelidonium majus, DNA intercalation, Tm

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2047 Towards a Resources Provisioning for Dynamic Workflows in the Cloud

Authors: Fairouz Fakhfakh, Hatem Hadj Kacem, Ahmed Hadj Kacem

Abstract:

Cloud computing offers a new model of service provisioning for workflow applications, thanks to its elasticity and its paying model. However, it presents various challenges that need to be addressed in order to be efficiently utilized. The resources provisioning problem for workflow applications has been widely studied. Nevertheless, the existing works did not consider the change in workflow instances while they are being executed. This functionality has become a major requirement to deal with unusual situations and evolution. This paper presents a first step towards the resources provisioning for a dynamic workflow. In fact, we propose a provisioning algorithm which minimizes the overall workflow execution cost, while meeting a deadline constraint. Then, we extend it to support the dynamic adding of tasks. Experimental results show that our proposed heuristic demonstrates a significant reduction in resources cost by using a consolidation process.

Keywords: cloud computing, resources provisioning, dynamic workflow, workflow applications

Procedia PDF Downloads 263
2046 System Survivability in Networks in the Context of Defense/Attack Strategies: The Large Scale

Authors: Asma Ben Yaghlane, Mohamed Naceur Azaiez, Mehdi Mrad

Abstract:

We investigate the large scale of networks in the context of network survivability under attack. We use appropriate techniques to evaluate and the attacker-based- and the defender-based-network survivability. The attacker is unaware of the operated links by the defender. Each attacked link has some pre-specified probability to be disconnected. The defender choice is so that to maximize the chance of successfully sending the flow to the destination node. The attacker however will select the cut-set with the highest chance to be disabled in order to partition the network. Moreover, we extend the problem to the case of selecting the best p paths to operate by the defender and the best k cut-sets to target by the attacker, for arbitrary integers p,k > 1. We investigate some variations of the problem and suggest polynomial-time solutions.

Keywords: defense/attack strategies, large scale, networks, partitioning a network

Procedia PDF Downloads 260
2045 Protection and Safeguarding of Groundwater in Algeria between Law and Right to Use

Authors: Aziez Ouahiba, Remini Boualem, Habi Mohamed

Abstract:

The growth and the development of a pay are strongly related to the existence or the absence of water in this area, the sedentary lifestyle of the population makes that water demand is increasing and the different brandishing (dams, tablecloths or other) are increasingly solicited. In normal time rain and snow of the winter period reloads the slicks and the wadis that fill dams. Over these two decades, Global warming fact that temperature is increasingly high and rainfall is increasingly low, which induces a charge less and less important tablecloths, add to that the strong demand in irrigation. Our study will focus on the variation of rainfall and irrigation, Their effects on the degree of pollution of the groundwater in this area based on statistical analyses by the Xlstat (ACP, correlation...) software for a better explanation of these results and determine the hydrochemistry of different groups or polluted areas pou be able to offer adequate solutions for each area.

Keywords: water in the basement, legislation, over exploitation, pollution, water prices

Procedia PDF Downloads 364
2044 Indoor Thermal Comfort in Educational Buildings in the State of Kuwait

Authors: Sana El-Azzeh, Farraj Al-Ajmi, Abdulrahman Al-Aqqad, Mohamed Salem

Abstract:

Thermal comfort is defined according to ANSI/ASHRAE Standard 55 as a condition of mind that expresses satisfaction with the thermal environment and is assessed by subjective evaluation. Sustaining this standard of thermal comfort for occupants of buildings or other enclosures is one of the important goals of HVAC design engineers. This paper presents a study of thermal comfort and adaptive behaviors of occupants who occupies two locations at the campus of the Australian College of Kuwait. A longitudinal survey and field measurement were conducted to measure thermal comfort, adaptive behaviors, and indoor environment qualities. The study revealed that female occupants in the selected locations felt warmer than males and needed more air velocity and lower temperature.

Keywords: indoor thermal comfort, educational facility, gender analysis, dry desert climate

Procedia PDF Downloads 137