Search results for: Mohammed Ben Ammar

Authors: Mohammed A. Hajeeh

Abstract:

Pumping systems are an integral part of water desalination plants, their effective functioning is vital for the operation of a plant. In this research work, the reliability and availability of pressurized pumps in a reverse osmosis desalination plant are studied with the objective of finding configurations that provides optimal performance. Six configurations of a series system with different number of warm and cold standby components were examined. Closed form expressions for the mean time to failure (MTTF) and the long run availability are derived and compared under the assumption that the time between failures and repair times of the primary and standby components are exponentially distributed. Moreover, a cost/ benefit analysis is conducted in order to identify a configuration with the best performance and least cost. It is concluded that configurations with cold standby components are preferable especially when the pumps are of the size.

Keywords: availability, cost/benefit, mean time to failure, pumps

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Authors: Shahruhaida Adayu Mohd Paili, Abd Latif Abdul Rahman, Asmadi Mohammed Ghazali

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Digital library was developed by many organizations, especially universities. The digital library can be considered as a new information system. Digital library brings many benefits to the users. There are many researches that have investigated the importance of the digital library, the acceptance, and continuance use of digital library. The investigation towards the digital library is important and it is crucial to understand the reason why users accept and continued use of digital library. Users can search the information and available resources through the digital library website. It is important to know the user’s perception towards the aesthetics of the digital library. Besides that, because of digital library provided information to the users, the researcher also needed to investigate the quality of information in digital library. This study used Extending the Unified Theory of Acceptance and Use of Technology (UTAUT2) in order to know the user’s intention to continued use of digital library.

Keywords: digital library, aesthetics, information quality, intention to continued use of digital library, UTAUT2

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Authors: Mohammed Jourdani, Hamid Mounir, Abdellatif El Marjani

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Proton exchange membrane fuel cells (PEMFCs) have been developed as a promising power source for transportation and stationary applications, and power devices for computers and mobile telephones. This paper discusses and summarizes the latest developments of materials and remaining challenges of PEMFC. The different contributions to the material of all components and the efficiencies are analyzed. Many technical advances are introduced to increase the PEMFC fuel cell efficiency and life time for transportation, stationary and portable utilization. By the last years the total cost of this system is decreasing. However, the remaining challenges that need to be overcome mean that it will be several years before full commercialization can take place.

Keywords: PEMFC fuel cell, materials, recent development, efficiency, life time, commercialization possibility

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Authors: Mohammed F. Almograbi

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For reinforced concrete panels the risk of failure due to compression -tension state of stresses, results from pure shear or torsion, can be a major problem. The present calculation methods for such stresses from multiple influences are without taking into account the softening of cracked concrete remains conservative. The non-linear finite element method has become an important and increasingly used tool for the analysis and assessment of the structures by including cracking softening and tension-stiffening. The aim of this paper is to test a computer program refined recently and to simulate the compression response of cracked concrete element and to compare with the available experimental results.

Keywords: reinforced concrete panels, compression-tension, shear, torsion, compression softening, tension stiffening, non-linear finite element analysis

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Authors: Abd Latif Abdul Rahman, Zuraidah Arif, Muhammad Faizal Iylia, Mohd Ghazali, Asmadi Mohammed Ghazali

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Mobile information is a significant access point for human information activities. Theories and models of human information behavior have developed over several decades but have not yet considered the role of the user’s computing device in digital information interactions. This paper reviews the literature that leads to developing a conceptual framework of a study on the managers mobile information behavior. Based on the literature review, dimensions of mobile information behavior are identified, namely, dimension information needs, dimension information access, information retrieval and dimension of information use. The study is significant to understand the nature of librarians’ behavior in searching, retrieving and using information via the mobile device. Secondly, the study would provide suggestions about various kinds of mobile applications which organization can provide for their staff to improve their services.

Keywords: mobile information behavior, information behavior, mobile information, mobile devices

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Authors: Hasanein Hasan, Mohammed Al-Taie, Basil Shanshool, Khalaf Abd-Ali

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This approach aims to deal with establishing and operating Iraqi Fibre-To-The-Home (FTTH) projects. The problems they suffer from are organized sabotage, vandalism, accidental damage and poor planning. It provides practical solutions that deal with the aforementioned problems. These solutions consist of both technical and financial clarifications that ensure the achievement of the FTTH network’s stability for the purpose of equipping citizens, private sector companies, and governmental institutions with services, data transmission, the Internet, and other services. They aim to solve problems and obstacles accompanying the operation and maintenance of FTTH projects implemented by the Informatics and Telecommunications Public Company (ITPC)/ Iraqi Ministry of Communications (MoC). This approach takes the FTTH network of AlMaalif-AlMuaslat districts/ Baghdad-Iraq as a case study.

Keywords: CCTV, FTTH, ITPC, MoC, NVR, PTZ

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Authors: Mahesh Hariharan, Rajan Balasubramaniam, Sharath Kumar Shetty, Shanthala Yadavalli, Mohammed Ahetasham, Sravya Devarapalli

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Acute abdomen is one of the most common clinical conditions requiring a radiological investigation. Ultrasound is the primary modality of choice which can diagnose some of the common causes of acute abdomen. However, sometimes the underlying cause for the pain is far more complicated than expected to mandate a high degree of suspicion to suggest further investigation with contrast-enhanced computed tomography or magnetic resonance imaging. Here, we have compiled a comprehensive series of selected cases to highlight the conditions which can be easily overlooked unless carefully sought for. This also emphasizes the importance of multimodality approach to arrive at the final diagnosis with an increased overall diagnostic accuracy which in turn improves patient management and prognosis.

Keywords: acute abdomen, contrast-enhanced computed tomography scan, magnetic resonance imaging, plain radiographs, ultrasound

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Authors: Safee Chaudhary, Mahnoor Naseer Gondal, Hira Anees Awan, Abdul Rehman, Ammar Arif, Risham Hussain, Huma Khawar, Zainab Arshad, Muhammad Faizyab Ali Chaudhary, Waleed Ahmed, Muhammad Umer Sultan, Bibi Amina, Salaar Khan, Muhammad Moaz Ahmad, Osama Shiraz Shah, Hadia Hameed, Muhammad Farooq Ahmad Butt, Muhammad Ahmad, Sameer Ahmed, Fayyaz Ahmed, Omer Ishaq, Waqar Nabi, Wim Vanderbauwhede, Bilal Wajid, Huma Shehwana, Muhammad Tariq, Amir Faisal

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Cancer is a manifestation of multifactorial deregulations in biomolecular pathways. These deregulations arise from the complex multi-scale interplay between cellular and extracellular factors. Such multifactorial aberrations at gene, protein, and extracellular scales need to be investigated systematically towards decoding the underlying mechanisms and orchestrating therapeutic interventions for patient treatment. In this work, we propose ‘TISON’, a next-generation web-based multiscale modeling platform for clinical systems oncology. TISON’s unique modeling abstraction allows a seamless coupling of information from biomolecular networks, cell decision circuits, extra-cellular environments, and tissue geometries. The platform can undertake multiscale sensitivity analysis towards in silico biomarker identification and drug evaluation on cellular phenotypes in user-defined tissue geometries. Furthermore, integration of cancer expression databases such as The Cancer Genome Atlas (TCGA) and Human Proteome Atlas (HPA) facilitates in the development of personalized therapeutics. TISON is the next-evolution of multiscale cancer modeling and simulation platforms and provides a ‘zero-code’ model development, simulation, and analysis environment for application in clinical settings.

Keywords: systems oncology, cancer systems biology, cancer therapeutics, personalized therapeutics, cancer modelling

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Authors: Sarra Roubi, Mohammed Erramdani, Samir Mbarki

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This paper presents an approach for the model-driven generating of Rich Internet Application (RIA) focusing on the graphical aspect. We used well known Model-Driven Engineering (MDE) frameworks and technologies, such as Eclipse Modeling Framework (EMF), Graphical Modeling Framework (GMF), Query View Transformation (QVTo) and Acceleo to enable the design and the code automatic generation of the RIA. During the development of the approach, we focused on the graphical aspect of the application in terms of interfaces while opting for the Model View Presenter pattern that is designed for graphics interfaces. The paper describes the process followed to define the approach, the supporting tool and presents the results from a case study.

Keywords: metamodel, model-driven engineering, MVP, rich internet application, transformation, user interface

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Authors: Turki Mohammed Al Mohaid

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High arousal may lead to inhibited athletic performance, or high positive arousal may enhance performance is controversial. To evaluate and review this issue, 31 athletes (all male) were induced into high pre-determined goal arousal and high arousal without pre-determined goal motivational states and tested on a standard grip strength task. Paced breathing was used to change psychological and physiological arousal. It was noted that significant increases in grip strength performance occurred when arousal was high and experienced as delighted, happy, and pleasant excitement in those with no pre-determined goal motivational states. Blood pressure, heart rate, and other indicators of physiological activity were not found to mediate between psychological arousal and performance. In a situation where athletic performance necessitates maximal motor strength over a short period, performance benefits of high arousal may be enhanced by designing a specific motivational state.

Keywords: high arousal, athletic, performance, physiological

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Authors: Amna Abdalla Mohammed Khalid, Pietro Parisse, Silvia Onesti, Loredana Casalis

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Basic cellular processes as DNA replication are crucial to cell life. Understanding at the molecular level the mechanisms that govern DNA replication in proliferating cells is fundamental to understand disease connected to genomic instabilities, as a genetic disease and cancer. A key step for DNA replication to take place, is unwinding the DNA double helix and this carried out by proteins called helicases. The archaeal MCM (minichromosome maintenance) complex from Methanothermobacter thermautotrophicus have being studied using Atomic Force Microscopy (AFM), imaging in air and liquid (Physiological environment). The accurate analysis of AFM topographic images allowed to understand the static conformations as well the interaction dynamic of MCM and DNA double helix in the present of ATP.

Keywords: DNA, protein-DNA interaction, MCM (mini chromosome manteinance) complex, atomic force microscopy (AFM)

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Authors: Kadda Amara, Mohammed Elkeurti, Mostefa Zemouli, Yassine Benallou

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In this work, we present a study of the structural, elastic and electronic properties of the cubic antiperovskites XNMg3 (X=P, As, Sb and Bi) using the full-potential augmented plane wave plus local orbital (FP-LAPW+lo) within the Generalized Gradient Approximation based on PBEsol, Perdew 2008 functional. We determined the lattice parameters, the bulk modulus B and their pressure derivative B'. In addition, the elastic properties such as elastic constants (C11, C12 and C44), the shear modulus G, the Young modulus E, the Poisson's ratio ν and the B/G ratio are also given. For the band structure, density of states and charge density the exchange and correlation effects were treated by the Tran-Blaha modified Becke-Johnson potential to prevent the shortcoming of the underestimation of the energy gaps in both LDA and GGA approximations. The obtained results are compared to available experimental data and to other theoretical calculations.

Keywords: XNMg3 compounds, GGA-PBEsol, TB-mBJ, elastic properties, electronic properties

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Authors: Jelena Zivkovic, Haidar Mohammed, Elaf Saeed

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Student affairs services play a critical role in contributing to the wholistic development and success of students as they progress through their academic careers. The study encompasses a multifaceted examination of student affairs service offerings amongst 10 private and 3 public Baghdad universities. Student affairs administrators (13) were surveyed along with over 300 students to determine university-sponsored services and student satisfaction and awareness. The student affairs service research findings varied significantly between private and public institutions and those that followed a national and international curriculum. Universities need to persist to adapt to changing demographics and technological advancements to enhance students' personal and academic successes, and student affairs services are key to preparing graduates to thrive in a diverse global world.

Keywords: student affairs, student success, higher education, Iraq, universities, Baghdad

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Authors: Belloufi Mohammed, Sellami Badreddine

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This paper deals with a new nonlinear modified three-term conjugate gradient algorithm for solving large-scale unstrained optimization problems. The search direction of the algorithms from this class has three terms and is computed as modifications of the classical conjugate gradient algorithms to satisfy both the descent and the conjugacy conditions. An example of three-term conjugate gradient algorithm from this class, as modifications of the classical and well known Hestenes and Stiefel or of the CG_DESCENT by Hager and Zhang conjugate gradient algorithms, satisfying both the descent and the conjugacy conditions is presented. Under mild conditions, we prove that the modified three-term conjugate gradient algorithm with Wolfe type line search is globally convergent. Preliminary numerical results show the proposed method is very promising.

Keywords: unconstrained optimization, three-term conjugate gradient, sufficient descent property, line search

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Authors: Abubakar Ahmed, Zainab Mohammed, Hadiza D. Nuhu, Hamisu Ibrahim

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Introduction: The plant Tacazzea apiculata Oliv (Periplocaceae) is widely distributed in tropical West Africa. It is claimed to have multiple uses in traditional medicine among which are its use to treat hemorrhoids, inflammations and cancers. Methods: Ethno-botanical survey through interview and using show-and-tell method of data collection were conducted among Hausa and Fulani tribes of northern Nigeria with the view to document useful information on the numerous claims by the local people on the plant. Results: The results revealed that the plant T. apiculata has relative popularity among the herbalist (38.2 %), nomads (14.8 %) and fishermen (16.0%). The most important uses of the plant in traditional medicine are inflammation (Fedelity level: 25.7 %) and Haemorrhoids (Fedelity level: 17.1 %) Conclusion: These results suggest the relevance of T. apiculata in traditional medicine and as a good candidate for drug Development.

Keywords: ethno-botany, periplocaceae, Tacazzea apiculata, traditional medicine

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Authors: Issam Derkaoui, Mohammed Khenfouch, Bakang M. Mothudi, Malik Maaza, Izeddine Zorkani, Anouar Jorio

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Transition metal oxides nanoparticles with different morphologies have attracted a lot of attention recently owning to their distinctive geometries, and demonstrated promising electrical properties for various applications. In this paper, we discuss the time and annealing effects on the structural and electrical properties of vanadium oxides nanoparticles (VO-NPs) prepared by microwave method. In this sense, transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman Spectroscopy, Ultraviolet-visible absorbance spectra (Uv-Vis) and electrical conductivity were investigated. Hence, the annealing state and the time are two crucial parameters for the improvement of the optoelectronic properties. The use of these nanostructures is promising way for the development of technological applications especially for energy storage devices.

Keywords: Vanadium oxide, Microwave, Electrical conductivity, Optoelectronic properties

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Authors: Ammar Asma, Bouafia Nabiha, Ghammam Rim, Ezzi Olfa, Ben Cheikh Asma, Mahjoub Mohamed, Helali Radhia, Sma Nesrine, Chouchène Imed, Boussarsar Hamadi, Njah Mansour

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Background: Central venous catheter associated infections (CVC-AI) are among the serious hospital-acquired infections. The aims of this study are to determine the incidence of CVC-AI, and their risk factors among patients followed in a Tunisian medical intensive care unit (ICU). Materials / Methods: A prospective cohort study conducted between September 15th, 2015 and November 15th, 2016 in an 8-bed medical ICU including all patients admitted for more than 48h. CVC-AI were defined according to CDC of ATLANTA criteria. The enrollment was based on clinical and laboratory diagnosis of CVC-AI. For all subjects, age, sex, underlying diseases, SAPS II score, ICU length of stay, exposure to CVC (number of CVC placed, site of insertion and duration catheterization) were recorded. Risk factors were analyzed by conditional stepwise logistic regression. The p-value of < 0.05 was considered significant. Results: Among 192 eligible patients, 144 patients (75%) had a central venous catheter. Twenty-eight patients (19.4%) had developed CVC-AI with density rate incidence 20.02/1000 CVC-days. Among these infections, 60.7% (n=17) were systemic CVC-AI (with negative blood culture), and 35.7% (n=10) were bloodstream CVC-AI. The mean SAPS II of patients with CVC-AI was 32.76 14.48; their mean Charlson index was 1.77 1.55, their mean duration of catheterization was 15.46 10.81 days and the mean duration of one central line was 5.8+/-3.72 days. Gram-negative bacteria was determined in 53.5 % of CVC-AI (n= 15) dominated by multi-drug resistant Acinetobacter baumani (n=7). Staphylococci were isolated in 3 CVC-AI. Fourteen (50%) patients with CVC-AI died. Univariate analysis identified men (p=0.034), the referral from another hospital department (p=0.03), tobacco (p=0.006), duration of sedation (p=0.003) and the duration of catheterization (p=0), as possible risk factors of CVC-AI. Multivariate analysis showed that independent factors of CVC-AI were, male sex; OR= 5.73, IC 95% [2; 16.46], p=0.001, Ramsay score; OR= 1.57, IC 95% [1.036; 2.38], p=0.033, and duration of catheterization; OR=1.093, IC 95% [1.035; 1.15], p=0.001. Conclusion: In a monocenter cohort, CVC-AI had a high density and is associated with poor outcome. Identifying the risk factors is necessary to find solutions for this major health problem.

Keywords: central venous catheter associated infection, intensive care unit, prospective cohort studies, risk factors

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Authors: Mohammed Alokshiya, Alaeddinne D. Eljamassi

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This study discusses the condition of bus service in Gaza Strip through testing certain hypotheses assuming that public is not satisfied with bus system in Gaza. This testing is proceeded using questionnaire. The study also includes the evaluation of ten bus stops in Gaza city as a case study using GIS, and suggests a design case study for the bus system in the university zone in Gaza city. The research indicates that there is a general dissatisfaction with bus system in Gaza Strip, with respect to buses in service, drivers and bus stops. The study also gives a design for a bus stop and its frequency in university zone in Gaza city. Finally, the researcher recommends that more interest should be given to bus system, through actual procedures such as insuring the suitability of bus for transferring passengers before updating bus license, decreasing taxes of importing new buses, and holding awareness raising sessions for bus drivers.

Keywords: public transport, bus system, public satisfaction, bus stop locating

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Authors: Tanghourte Mohamed, Ouassou Nazih, El Mesky Mohammed, Znini Mohamed, Mabrouk El Houssine

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In the present study, a distinct organic inhibitor, namely 2,2'-(piperazine-1,4-diyl)bis(N-(4-bromophenyl)acetamide) (PBRA), was synthesized and characterized using ¹H, ¹³C NMR, and IR spectroscopy. Subsequently, the inhibition effect of PBRA on the corrosion of carbon steel in 1 M HCl was studied using electrochemical measurements such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results showed that the inhibition efficiency increased with concentration, reaching 87% at 10-³M. Furthermore, PBRA remained effective at temperatures ranging from 298 to 328 K. The adsorption of the inhibitor onto carbon steel was well described by the Langmuir adsorption isotherm. Additionally, a correlation between the molecular structure and quantum chemistry indices was established using density functional theory (DFT).

Keywords: synthesis, corrosion, inhibition, piperazine, efficacy, isotherm, acetamide

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Authors: Belloufi Mohammed, Sellami Badreddine

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Conjugate gradient methods have played a special role for solving large scale optimization problems due to the simplicity of their iteration, convergence properties and their low memory requirements. In this work, we propose a new class of conjugate gradient methods which ensures sufficient descent. Moreover, we propose a new search direction with the Wolfe line search technique for solving unconstrained optimization problems, a global convergence result for general functions is established provided that the line search satisfies the Wolfe conditions. Our numerical experiments indicate that our proposed methods are preferable and in general superior to the classical conjugate gradient methods in terms of efficiency and robustness.

Keywords: unconstrained optimization, conjugate gradient method, sufficient descent property, numerical comparisons

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Authors: Noura Al-Ajmi, Mohammed A. Almulla

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With the increased utilization of technology devices around the world, healthcare and medical diagnosis are critical issues that people worry about these days. Doctors are doing their best to avoid any medical errors while diagnosing diseases and prescribing the wrong medication. Subsequently, artificial intelligence applications that can be installed on mobile devices such as rule-based expert systems facilitate the task of assisting doctors in several ways. Due to their many advantages, the usage of expert systems has increased recently in health sciences. This work presents a backward rule-based expert system that can be used for a headache diagnosis and medication recommendation system. The structure of the system consists of three main modules, namely the input unit, the processing unit, and the output unit.

Keywords: headache diagnosis system, prescription recommender system, expert system, backward rule-based system

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Authors: Mohammed A. Abutalib

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Papillary thyroid carcinoma (PTC) accounts for the most common type of thyroid cancer, a well-differentiated type. PTC is featured by biologically low-grade and less aggressive tumors with a survival rate of 10 years in most of the diagnosed cases. PTC can be presented with the involvement of cervical lymph nodes in about 50% of the patients, yet the distant spread is very uncommon. Herein, we discussed an early 50-year-old male patient with a history of PTC that presented to the emergency department complaining of shortness of breath and a radiological finding of hydrothorax. Cytologic examination, together with immune-histochemical staining and molecular studies of pleural effusion aspiration, concluded the definitive diagnosis of metastatic papillary thyroid carcinoma in the pleural space. PTC seldom causes metastatic niches in the pleural space, and this is a rare clinical presentation; nevertheless, a differential diagnosis of thyroid metastasis needs to be excluded.

Keywords: thyroid cancer, malignant pleural effusion, cytology aspiration, papillary thyroid carcinoma

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Authors: Mohammed Sharaf, Alireza Shokri, Adrian Small, Toby Bridges

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This paper investigates digital transformation challenges in SMEs within the automotive supply chain. A case study approach and participant observation revealed significant data management and process optimization barriers, corroborated by a conceptual model. Stakeholder feedback, visualized through a pie chart, emphasized data management and process efficiency as primary concerns. Recommended strategies include implementing advanced data systems, process simplification, and enhancing digital skills. Despite the single-case study limitation, the findings offer actionable insights for SMEs to leverage Industry 4.0 technologies effectively. This research contributes to the strategic roadmap necessary for SMEs to achieve competitive digital transformation.

Keywords: automotive supply chain, digital transformation, industry 4.0

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Authors: Nefzi Ahlem, Aydi Ben Abdallah Rania, Jabnoun-Khiareddine Hayfa, Ammar Nawaim, Mejda Daami-Remadi

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Fusarium Crown and Root Rot (FCRR) caused by Fusarium oxysporum f. sp. radicis-lycopersici (FORL) is a serious tomato (Solanum lycopersicum L.) disease in Tunisia. Its management is very difficult due to the long survival of its resting structures and to the luck of genetic resistance. In this work, we explored the wild Solanaceae species Withania somnifera, growing in the Tunisian Centre-East, as a potential source of biocontrol agents effective in FCRR suppression and tomato growth promotion. Seven fungal isolates were shown able to colonize tomato roots, crowns, and stems. Used as conidial suspensions or cell-free culture filtrates, all tested fungal treatments significantly enhanced tomato growth parameters by 21.5-90.3% over FORL-free control and by 27.6-93.5% over pathogen-inoculated control. All treatments significantly decreased the leaf and root damage index by 28.5-92.8 and the vascular browning extent 9.7-86.4% over FORL-inoculated and untreated control. The highest disease suppression ability (decrease by 86.4-92.8% in FCRR severity) over pathogen-inoculated control and by 81.3-88.8 over hymexazol-treated control) was expressed by I6 based treatments. This endophytic fungus was morphologically characterized and identified using rDNA sequencing gene as Fusarium sp. I6 (MG835371). This fungus was shown able to reduce FORL radial growth by 58.5–83.2% using its conidial suspension or cell-free culture filtrate. Fusarium sp. I6 showed chitinolytic, proteolytic and amylase activities. The current study clearly demonstrated that Fusarium sp. (I6) is a promising biocontrol candidate for suppressing FCRR severity and promoting tomato growth. Further investigations are required for elucidating its mechanism of action involved in disease suppression and plant growth promotion.

Keywords: antifungal activity, associated fungi, Fusarium oxysporum f. sp. radicis-lycopersici, Withania somnifera, tomato growth

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Authors: Ngozi Nwogu, Mohammed Kajama, Emmanuel Anyanwu, Edward Gobina

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With the objective to create technologically advanced materials to be scientifically applicable, multi-layer silica alumina membranes were molecularly fabricated by continuous surface coating silica layers containing hybrid material onto a ceramic porous substrate for flue gas separation applications. The multi-layer silica alumina membrane was prepared by dip coating technique before further drying in an oven at elevated temperature. The effects of substrate physical appearance, coating quantity, the cross-linking agent, a number of coatings and testing conditions on the gas separation performance of the membrane have been investigated. Scanning electron microscope was used to investigate the development of coating thickness. The membrane shows impressive perm selectivity especially for CO2 and N2 binary mixture representing a stimulated flue gas stream

Keywords: gas separation, silica membrane, separation factor, membrane layer thickness

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Authors: Murtala Mohammed Alamai, Abdullahi Marshal Idris, Adama Idris

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Today, marketing does not only involve selecting target markets, but it also involves communicating with the customers through various means to put across your selling point. Modern marketing involves driving new product development based on customer needs by getting feedback from them. Utilizing the latest technology for better communication with the customers is the latest advancement in Marketing in the 21st century. The survey approach was used where a sample of tourist destinations across the six geographical zones of the country at random was done to ascertain the use of information communication systems in promoting their products and or services, the findings revealed that only a few utilize these modern advanced means in marketing and promoting their products and a need to develop effective and up to date online services for marketing was proffered as solutions to the findings observed.

Keywords: information, communication, travel, trade, promotion

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Authors: Mohammed Mahmoud Osman Ahmed, Akram Mohammad

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Flame dynamics in heated quartz glass channels of various aspect ratios (2,5,10,15) were experimentally investigated. A premixed Propane-air mixture was used for the reported experiments. Regarding micro-combustion, flame quenching is considered to be the most crucial problem to overcome first. Experiments were carried out on four channels with different aspect ratios. The results show that at a very low equivalence ratio ϕ=0.4, there is no flame inside the channels. The FREI condition (Flame with repetitive extinction and ignition) was overcome by increasing velocity and by making the channels more in contact with the external heater. The flame tested inside the channels at different locations for V=0.3 m/s or higher below V=0.65 m/s. The effects of equivalence ratio and flow velocity on the characteristics of combustion in the channels were examined. Different ways of flame propagation were observed in the current investigations based on how they appear as planar, concave and convex flames.

Keywords: flame stabilization, combustion, flame dynamics, small-scale channels, external heater

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Authors: Mohammed S. Assiri

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In EFL programs, rating scales used in writing assessment are often constructed by intuition. Intuition-based scales tend to provide inaccurate and divisive ratings of learners’ writing performance. Hence, following an empirical approach, this study attempted to develop a rating scale for elementary-level writing at an EFL program in Saudi Arabia. Towards this goal, 98 students’ essays were scored and then coded using comprehensive taxonomy of writing constructs and their measures. An automatic linear modeling was run to find out which measures would best predict essay scores. A nonparametric ANOVA, the Kruskal-Wallis test, was then used to determine which measures could best differentiate among scoring levels. Findings indicated that there were certain measures that could serve as either good predictors of essay scores or differentiators among scoring levels, or both. The main conclusion was that a rating scale can be empirically developed using predictive and discriminative statistical tests.

Keywords: analytic scoring, rating scales, writing assessment, writing constructs, writing performance

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Authors: Selcuk Comlekci, Mohammed Aboajmaa

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Orthogonal frequency division multiplexing (OFDM) is promising technique for the modern wireless communications systems due to its robustness against multipath environment. The high peak to average power ratio (PAPR) of the transmitted signal is one of the major drawbacks of OFDM system, PAPR degrade the performance of bit error rate (BER) and effect on the linear characteristics of high power amplifier (HPA). In this paper, we proposed DHT-Clipping reduction technique to reduce the high PAPR by the combination between discrete Hartley transform (DHT) and Clipping techniques. From the simulation results, we notified that DHT-Clipping technique offers better PAPR reduction than DHT and Clipping, as well as DHT-Clipping introduce improved BER performance better than clipping.

Keywords: ISI, cyclic prefix, BER, PAPR, HPA, DHT, subcarrier

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Authors: Bourfaa Fouzia, Meryem Lamri Zeggar, Adjimi Amel, Mohammed Salah Aida, Nadir Attaf

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Semiconductor photocatalysts such as ZnO has attracted much attention in recent years due to their various applications for the degradation of organic pollutants in water, air and in dye sensitized photovoltaic solar cell. In the present work, ZnO thin films were prepared by ultrasonic spray pyrolysis by using different precursors namely: Acetate, chloride and zinc nitrate in order to investigate their influence on ZnO photocatalytic activity. The films crystalline structure was studied by mean of X-ray diffraction measurements (XRD) and the films surface morphology by Scanning Electron Microscopy (SEM). The films optical properties were studied by mean of UV–visible spectroscopy. The prepared films were tested for the degradation of the red reactive dye largely used in textile industry. As a result, we found that the zinc nitrate is the best precursor to prepare ZnO thin films suitable for a good photocatalytic activity.

Keywords: precursor, thins films, spray pyrolysis, zinc oxide

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