Modeling and Simulation of Linear and Nonlinear Dynamic Model for Double Inverted Pendulum on Cart System

This paper displays linear and nonlinear model for double inverted pendulum system depended on Lagrange equation and the system response for linear and nonlinear of DIPS are noted and analyzed. The inverted pendulum has been advanced for a laboratory experiments.  The essential variance between the linear and nonlinear equation is present. This analysis is useful for progress of effective controller for a DIPS

Considering the Specific Impact of Harsh Conditions and Oil Weathering on Diversity, Adaptation, and Activity of Hydrocarbon-Degrading Bacteria in Strategies of Bioremediation of Harsh Oily-Polluted Soils

Weathering processes change properties and composition of spilled oil, representing the main reason of failure of bioaugmentation strategies. Our purpose was to investigate the metabolic adaptation of hydrocarbon-degrading bacteria at harsh conditions to be considered to overcome the limitations of bioaugmentation strategies at harsh conditions. Polluted soils, exposed for prolonged periods to weathered oil in harsh soils and weather conditions, were used. Two types of enrichment cultures were employed using 5% and 10% oil or diesel as sole carbon sources with varying the mineral nitrogen sources and C/N ratios. The most effective isolates were obtained based on growth, tolerance to toxicity, and removal efficiency of diesel hydrocarbons. Activities of the newly isolated bacteria, in relation to the microenvironment from where they were isoalted and their interaction with the weathered oil, showed individual specific ability to adapt when exposed to such factors, to acquire metabolic potentialities. Among 39 isolates, ten identified ones by 16S rDNA genes similarities, including special two Pseudomonas isolates and one Citrobacter isolate, showed particularity of shifting hydrocarbon-degrading ability from short chain n-alkanes (n-C12–n-C16) to longer chain n-alkanes (n-C21–n-C25) and vice versa by alternating nitrogen source compositions and C/N ratios. This is shown for the first time.This work was supported by the College of Arts and Sciences and Department of Biological and Environmental Sciences of Qatar University [QUUG-CAS-DEM-12/13-6; QUST-CAS-FALL-12/13-23; and QUST-CAS-FALL-12/13-22]

Health and Safety Concerns: Quantitative Studies of Leaching of Metals from Glazed Surfaces of Traditional Ceramic Potteries

Traditional ceramic wares have been known as a source of heavy metals poisoning. Traditional ceramic potteries may be improperly glazed, and the glaze used to make the pottery may contain over amounts of heavy metals. These over glazed ceramic wares can release deadly metal into foodstuff and constitute health hazards. In this work, Quantitative studies were done according to ASTM C 738.81 (1982) leaching standard test methods for the determination of trace amount of selected metals from glazed surfaces of traditional ceramic potteries by 4% acetic and 2% citric acid standard solutions at different temperatures. Finally, leaching potential has been done using ICP-MS analysis. The capacity of each ceramic tableware sample ranged between 250 and 350ml. The ceramic wares selected randomly from products available in the local markets at Doha (Qatar), Cairo (Egypt) and Gharyan (Libya)

Effective NiMn nanoparticles-functionalized carbon felt as an effective anode for direct urea fuel cells

The internal resistances of fuel cells strongly affect the generated power. Basically, in the fuel cell, the anode can be prepared by deposition of a film from the functional electrocatalyst on a proper gas diffusion layer. Accordingly, an interfacial resistance for the electron transport is created between the two layers. Electrocatalyst-functionalized gas diffusion layer (GDL) can distinctly reduce the interfacial resistance between the catalyst layer and the GDL. In this study, NiMn nanoparticles-decorated carbon felt is introduced as functionalized GDL to be exploited as a ready-made anode in a direct urea fuel cell. The proposed treated GDL was prepared by calcination of nickel acetate/manganese acetate-loaded carbon felt under an argon atmosphere at 850 °C. The physiochemical characterizations confirmed complete reduction for the utilized precursors and deposition of pristine NiMn nanoparticles on the carbon felt fiber. In passive direct urea fuel cells, investigation the performance of the functionalized GDLs indicated that the composition of the metal nanoparticles has to be optimized as the GDL obtained from 40 wt % manganese acetate reveals the maximum generated power density; 36 mW/m2 at room temperature and 0.5 M urea solution. Moreover, the electrochemical measurements proved that low urea solution concentration is preferred as utilizing 0.5 M solution resulted into generating higher power compared to 1.0 and 2.0 M solution. Overall, this study opens a new avenue toward functionalization of the GDL as a novel strategy to overcome the interfacial resistance between the electrocatalyst and the GDL. View Full-TextFunding: This publication was made possible by NPRP grant # [8-1344-1-246] from Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of authors. Acknowledgments: All authors gratefully acknowledge the support of Qatar Foundation.Scopu

Selenium, Selenoproteins, and Heart Failure:Current Knowledge and Future Perspective

PURPOSE OF REVIEW: (Mal-)nutrition of micronutrients, like selenium, has great impact on the human heart and improper micronutrient intake was observed in 30–50% of patients with heart failure. Low selenium levels have been reported in Europe and Asia and thought to be causal for Keshan disease. Selenium is an essential micronutrient that is needed for enzymatic activity of the 25 so-called selenoproteins, which have a broad range of activities. In this review, we aim to summarize the current evidence about selenium in heart failure and to provide insights about the potential mechanisms that can be modulated by selenoproteins. RECENT FINDINGS: Suboptimal selenium levels (<100 μg/L) are prevalent in more than 70% of patients with heart failure and were associated with lower exercise capacity, lower quality of life, and worse prognosis. Small clinical trials assessing selenium supplementation in patients with HF showed improvement of clinical symptoms (NYHA class), left ventricular ejection fraction, and lipid profile, while governmental interventional programs in endemic areas have significantly decreased the incidence of Keshan disease. In addition, several selenoproteins are found impaired in suboptimal selenium conditions, potentially aggravating underlying mechanisms like oxidative stress, inflammation, and thyroid hormone insufficiency. SUMMARY: While the current evidence is not sufficient to advocate selenium supplementation in patients with heart failure, there is a clear need for high level evidence to show whether treatment with selenium has a place in the contemporary treatment of patients with HF to improve meaningful clinical endpoints. GRAPHICAL ABSTRACT: [Figure: see text

Fuzzy-GRA trust model for cloud risk management

Cloud computing is not adequately secure due to the currently used traditional trust methods such as global trust model and local trust model. These are prone to security vulnerabilities. This paper introduces a trust model based on the fuzzy mathematics and gray relational theory. Fuzzy mathematics and gray relational analysis (Fuzzy-GRA) aims to improve the poor dynamic adaptability of cloud computing. Fuzzy-GRA platform is used to test and validate the behavior of the model. Furthermore, our proposed model is compared to other known models. Based on the experimental results, we prove that our model has the edge over other existing models

Engineering of magnetically separable ZnFe2O4@ TiO2 nanofibers for dye-sensitized solar cells and removal of pollutant from water

Abstract In this study, magnetic Zinc Ferrite (ZnFe2O4)@TiO2 nanofibers were prepared by low cost and nontoxic route; hydrothermal technique followed by electrospinning process. The prepared magnetic ZnFe2O4@TiO2 nanofibers were morphologically and structurally analyzed by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and thermal gravimetric analysis (TGA). The prepared magnetic ZnFe2O4@TiO2 nanofibers were utilized as photoanode for the fabrication of dye-sensitized solar cells (DSSCs) and presented applicable performance with 4.2% overall conversion efficiency with high short circuit current density (JSC) of 10.16 mA/cm2. The maximum ∼42% incident photo-to-current conversion efficiency (IPCE) value was also recorded at 520 nm. In addition, ZnFe2O4@TiO2 nanofibers were not only possessed the good conversion efficiency, but also shown excellent photocatalytic efficiency with magnetic properties towards the dye remediation. Prepared ZnFe2O4@TiO2 nanofibers can be considered as a promising material for energy conversion and environmental applications

ZnO@C (core@shell) microspheres derived from spent coffee grounds as applicable non-precious electrode material for DMFCs

Although numerous reports have introduced non precious electrocatalysts for methanol oxidation, most of those studies did not consider the corresponding high onset potential which restricts utilization in real fuel cells. In this study, an −90 mV [vs. Ag/AgCl] onset potential non-precious electrocatalyst is introduced as an applicable anode material for the direct methanol fuel cells. Moreover, the proposed material was prepared from a cheap and abundantly existing resource; the spent coffee grounds. Typically, the spent coffee grounds were facilely converted to core@shell (ZnO@C) microspheres through a two-step approach, involving chemical activation and a subsequent calcination at temperature of 700 °C. Activation of the carbon derived from the spent coffee grounds was performed with ZnCl2 which acts as pore-forming agent as well as a precursor for the ZnO. The structure and morphology were characterized by (XRD), (SEM), and (TEM) analyses while the electrochemical characterizations was evaluated by cyclic voltammetry (CV) technique. Besides the comparatively very low onset potential, the introduced microspheres exhibited relatively high current density; 17 mA/cm2. Overall, based on the advantages of the green source of carbon and the good electrocatalytic activity, the spent coffee grounds-derived carbon can be considered a promise anode material for the DMFCs.This Publication was made possible by NPRP grant # [8-1344-1-246] from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of authors

Patulin and patulin producing Penicillium spp. occurrence in apples and apple-based products including baby food

Introduction: Patulin has raised the international attention because of its health risk. In fact, it has mutagenic, neurotoxic, immunotoxic, genotoxic and gastrointestinal effects in animals. In the present work, patulin and patulin-producing Penicillium spp. in apple and apple-based products marketed in Qatar were analysed. Methodology: Sampling was carried out using apple fruits and apple-based products. Fungi were isolated from undamaged apples, apple juice and baby apple food. DNA extraction was carried out with DNeasy Plant Mini Kit (QIAGEN, Valencia, USA). The molecular identification of fungal isolates was carried out using ITS1-ITS4 PCR. PCR products were sequenced and blasted. Patulin was extracted and analyzed by LC/MS/MS, then quantified using Agilent 1290UHPLC coupled to 6460 triple quadruple mass spectrometer. Results: Forty-five samples of undamaged fresh apple fruits, apple juice and apple-based baby food products sold in different markets in Qatar were surveyed for both fungal and patulin contamination using Liquid Chromatography Tandem Mass Spectrometery (LC/MS/MS). Twenty-five Penicillium spp. isolates were selected, including 23 P. expansum and one isolate each of P. brevicompactum and P. commune. All the tested Penicillium spp. isolates produced patulin in vitro (from 40 to 100 μg/g on Malt Yeast Extract agar medium). Patulin was detected in 100% of apple juice samples at levels ranging from 5.27 to 82.21 μg/kg. Only 5 samples contained patulin levels higher than European Union recommended limit (50 μg/kg). The average patulin contamination was 30.67 μg/kg and 10.92 μg/kg in baby apple juice and in baby apple compote, respectively.This publication was made possible by NPRP grant # NPRP 4-259-2-083 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors

Knowledge and Attitude of Saudi Arabian School Teachers with Regards to Emergency Management of Dental Trauma

Injury to both the primary and the permanent dentitions and their supporting structures is one of the most common dental problems seen in children.&nbsp; School is one of the locations with greatest prevalence of occurrence of traumatic dental injuries.&nbsp; School teachers play important role in prevention of dental trauma and improving its prognosis. The present study was undertaken to assess knowledge and attitudes regarding emergency management of dental trauma, first aid for avulsed tooth and influence of dental education among school teachers in Abha city. METHODS: The participants were 100 school teachers from Abha city and were interviewed using a questionnaire regarding management of dental trauma.&nbsp; The completed proformas was collected and the result was statistically analyzed to know the knowledge and attitudes regarding emergency management of dental trauma. CONCLUSIONS: Majority of school staff had little knowledge related to handling of traumatic dental injuries and emergency management of avulsed permanent teeth in school children. Majority of school teachers were eager to have knowledge regarding dental trauma through continues dental education programs and workshops.&nbsp; First aid training increases knowledge about dental trauma and should be included in the course curriculum of teachers training program