A Variable Speed Synchronous Motor Approach for Smart Irrigation using Doubly Fed Induction Motor

Department of Electrical Engineering, College of Engineering, Jazan University, Jizan 45142, Saudi Arabia.Doubly Fed Induction Motor (DFIM) is a popular machine used in variable speed drives, and its ruggedness, reliability and simplicity of speed control make it a suitable candidate for use in smart irrigation systems. This paper studies and evaluates the performance of DFIM at different operating conditions and shows that it can be viewed as a variable speed synchronous motor. The research results reveal that DFIM can be used to control the flow rate of water in irrigation systems, by adjusting the speed of the motor to match the desired flow rate. A mathematical model has been developed to optimize the performance of the DFIM in smart irrigation systems, taking into account the specific conditions of the application. In addition, an experimental setup was built and tested to enhance the theoretical results, which showed good correlation between the theoretical and experimental results. The results of this research demonstrate the potential of using the DFIM in smart irrigation systems to improve the performance and efficiency of irrigation and to provide better control and lower costs

Factors and affect mobile telephone users to use mobile payment solution

Providing a convenient payment solution to mp3 users is one of the alternatives that can promote legal mp3 downloading. However, before the success of the payment solution can be determined, it is essential to understand whether it would be well-accepted by the users. This paper examines factors that influence the intention to use a mobile payment solution for mp3 downloading among university' students. Drawing from the Technology Acceptance Model, Theory of Planned Behaviour and previous literatures, five factors were hypothesized to influence the intention to use the payment solution, namely perceived usefulness, perceived ease of use, trust, perceived price level, and peer influence. Final year business students at a public university in the southern part of Malaysia were chosen as respondents for this study. Multiple regressions were employed to analyze the data. Two factors were found to have significant effect on the intention to use the payment solution, which were trust and peer influence. Practical implications were proposed and discussed

Investigation on Effects of Avocado Extract as Eco-friendly Inhibitor for 201 Stainless Steel corrosion in Acidic Environment

The inhibitory effect of using avocado extract (AE) on the corrosion of stainless steel type 201 (201SS) in 1M hydrochloric acid has been studied. Chemical tests such as mass loss test (ML) and electrochemical such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) were used in this investigation. The results of these approaches showed that as the concentration of AE extract increase, their adsorption on the 201SS surface increases, and therefore the corrosion process lower. The Langmiur isotherm was observed to represent the adsorption of this extract on the surface of 201-SS. The inhibitory efficiency percent (%IE) and activation energy (Ea) were calculated in the presence and absence of AE. The corrosion rate was calculated and revealed that AE has good inhibition effect on 201-SS alloy surface inspection methods such as SEM, AFM, and FT-IR have also been used. It was found that all of these used methods are in agreement with each other

A Descriptive Framework for the Field of Knowledge Management

Despite the extensive evolution of knowledge management (KM), the field lacks an integrated description. This situation leads to difficulties in research, teaching, and learning. To bridge this gap, this study surveys 2842 articles from top-ranked KM journals to provide a descriptive framework that guides future research in the field of knowledge management. This study also seeks to provide a comprehensive depiction of current research in the field and categorizes these research activities into higher-level categories using grounded theory approach and topic modeling technique. The results show that KM studies are classified into four core research categories: technological, business, people, and domains/applications dimensions. An additional concern addressed in this study is the major research methodologies used in this field. The results raise awareness of the development of KM discipline and hold implications for research methodologies and research trends in the selected KM journals. The results obtained from this study also provide practitioners with a useful quality reference source. The framework and the components included provide researchers, practitioners, and educators with an ontology of KM topics, where they can cover deficiencies in research and provide an agenda for future research

Oral Surgery, Oral Medicine

Abstract Central Odontogenic Fibroma (COF) is a rare, benign neoplasm of mesenchymal origin that makes up less than 5% of odontogenic tumors commonly found in women in ratio 2.8:1. For many years there was considerable confusion concerning the criteria by which the lesion should be diagnosed and as a result, a verity of different conditions were being reported as odontogenic fibroma (OF). In this article reporting a case of COF (Epithelium Rich-type) in the maxilla radiographically presented as a well-defined radiolucent and radiopaque lesion retarding the first premolar from erupting plus reviewing the literature about COF including its variants

When Users Enjoy Using the System: The Case of AIS

This study utilized an extended model of the Unified Theory of Acceptance and Use of Technology (UTAUT2) to explore the factors influencing the future adoption of accounting information systems (AIS) by Qatari students. A research model was proposed to predict future adoption, partially moderated by voluntary status of using the system. A sample of 237 students was used to probe their perceptions regarding the use of such systems in their future careers. Students were enrolled in an accounting information systems course in Qatar University. Results indicated that perceived facilitating conditions, performance expectancy and enjoyment were significant predictors of AIS. The other factors failed to be significant predictors. The estimated R2 was 48.4%. The moderation effect of voluntariness was also significant in influencing the relationship between enjoyment and future adoption. The moderator yielded a negative beta, which means that it faded the relationship under consideration. Conclusions and future recommendations are reported at the end of the paper

Cytotoxic and antioxidant properties of active principals isolated from water hyacinth against four cancer cells lines

BACKGROUND: Eichhornia crassipes (Mart) solms is an invasive macrophyte causing serious problems to the network of irrigation and drainage canals in the Nile Delta region. The present study aim to evaluate the potential anticancer and antioxidant activities of Eichhornia crassipes crude extract and its pure compounds. METHODS: The macrophyte was collected from El-Zomor canal, River Nile (Egypt), cleaned, air dried, grinded then extracted with methanol (crude extract). The extract was fractionated using pre-coated silica gel plates (TLC F(254)) with hexane/ethyl acetate (8.5: 1.5 v/v) as mobile phase. Nine fractions were separated (A-I) then scratched, eluted with the same mobile phase, filtered and the separated fractions were determined and identified using spectroscopic methods (Mass spectrum (MS), Infra red (IR) and Proton H-Nuclear magnetic resonance (H-NMR). Both the crude extract and its nine identified compounds were tested for their antioxidant (using 2, 2 diphenyl-1-picrylhydrazyl (DPPH), 2, 2′- azino-bis {ethylbenzthiazoline-6-sulfonic acid (ABTS(.))} methods) and anticancer activity (using MCF-7, HeLa, Hep.G2 and EACC cell lines). RESULTS: The antioxidant and anticancer activities of the crude extract exhibited the highest effect while the compounds showed variable effects which depend on the type of compound and cancer cell line. The antioxidant activity of the crude extract exhibited the highest followed in descending order by compounds D, E, G and H respectively. Concerning the anticancer potency, the crude extract showed also the highest effect while the identified compounds (A, B, C, D, E, F, G, H and I) showed variable anticancer activities against the four different cell lines. In addition, Compound I exhibited the most potent anticancer activity against HepG2 cell line while compound D exhibited high anticancer activity against HeLa cells and EACC. The results revealed the presence of different compounds (Alkaloids and terpenoids) with variable antioxidant and anticancer activities which elicited an auto-augmentation in the crude extract leading to its greatest activities. The action of the identified anticancer compounds on DNA fragmentation was studied. CONCLUSION: The study illustrated the potential of Eichhornia as a valuable resource for natural compounds of desirable medicinal properties (e.g. antioxidants and anticancer)

Immunological Markers in Children with Genetic Disorders and Recurrent Respiratory Tract Infections

BACKGROUND: Recurrent respiratory tract infections (RRI) are one of the extremely high common reasons for pediatric visits and hospitalization. Immunodeficiencies are considered as important conditions that may increase the probability of occurrence of RRI. Mannose-binding lectin (MBL2) is a protein of the innate immune system involved in the opsonization and the complement activation. MBL2 deficiency is associated with infectious diseases mainly chest infections; however, subnormal MBL2 levels are also seen in healthy subjects. Primary immunedeficiencies are associated with recurrent infections which mainly appear in early childhood. AIM: The aim of the study was to estimate T and B and natural killer cells percentage and to investigate the MBL2 and immunoglobulins (Igs) serum levels in children with recurrent RRIs in different genetic disorders compared to normal control. METHODS: This study included 50 children having a history of recurrent RRIs. All patients had genetic disorders and referred to National Research Centre for follow-up, in addition to, 25 children, age- and sex-matched as a healthy control group. They were subjected to full clinical examination and laboratory investigations including complete blood count (CBC), CD3, CD4, CD8, CD16, and CD19 by flow cytometry, MBL2 by enzyme-linked immunosorbent assay (ELISA), and Igs serum concentrations by nephelometry. RESULTS: CD16 showed a non-statistical significant difference between both patient groups. Serum levels of IgA in patient groups showed a significant decrease compared to the control group. Moreover, the serum level of IgM results shows a highly significant decrease when compared with the control group. There was no statistically significant difference in MBL2 and IgG serum levels between patient groups and control group. CONCLUSION: Children with genetic disorders and recurrent RRIs showed a statistically significant decrease of IgA and IgM serum levels as compared to the control group, while the serum level of MBL2 did not show significant results