326 research outputs found

    Stratégies de l'enseignement supérieur au Liban : Université libanaise et Universités privées

    Get PDF

    Design and construction of anair pollution detection system using a laser beam and absorption spectroscopy

    Get PDF
            تلوث الهواء من المشاكل المهمة التي تواجه العراق.  ينتج تلوث الهواء عن مصانع الانبعاثات غير الخاضعة للرقابة ، والمولدات الكهربائية لعوادم السيارات ، ومصافي النفط وغيرها من المصادر والتي غالبًا ما يصل إلى حدود غير مقبولة وفقًا للمعايير الدولية.  يمكن أن تؤثر هذه الملوثات بشكل كبير على صحة الإنسان والأنشطة السكانية العادية.  لهذا السبب هناك حاجة ملحة لأجهزة فعالة لرصد التركيز الجزيئي لملوثات الهواء في المدن والمناطق الحضرية. تم في هذا البحث بناء نظام بصري يتكون من ليزر هيليوم - نيون 5 ميغاواط  وبطول موجي 632.8 نانومتر ، خلية زجاجية ذات حجم محدد ، ومقياس طاقة (Gentec - E - model: uno) حيث يحدث تشتت شعاع الليزر  بسبب تلوث الهواء.  تم الكشف عن نوعين من الملوثات هما بخار الماء و الدخان.  وقد أجريت تجارب باستخدام هذه الملوثات لمعايرة النظام وتحديد حساسية الكشف له باستخدام هذه التقنية حيث تم تحديد معاملات الامتصاص وأنواع الملوثات وتركيزاتها.Air pollution is one of the important problems facing Iraq. Air pollution is the result of uncontrolled emissions from factories, car exhaust electric generators, and oil refineries and often reaches unacceptable limits by international standards. These pollutants can greatly affect human health and regular population activities. For this reason, there is an urgent need for effective devices to monitor the molecular concentration of air pollutants in cities and urban areas. In this research, an optical system has been built consisting of aHelium-Neonlaser,5mWand at 632.8 nm, a glass cell with a defined size, and a power meter(Gentec-E-model: uno) where a scattering of the laser beam occurs due to air pollution. Two pollutants were examined: water vapor and smoke. Experiments were conducted using these pollutants to calibrate the system and determine its detection sensitivity. With this technique the absorption coefficients, types of pollutants and their concentrations were determined

    Efficacy of Corn and Rice Seed-borne Mycoflora in Controlling Aflatoxigenic Aspergillus flavus

    Get PDF
    Food commodities such as cereals are subjected to spoilage and bio-deterioration during storage by mycotoxigenic fungi such as Aspergillus flavus. Efforts are done to biologically control toxigenic A. flavus and subsequently prevent or at least minimize its aflatoxin production ability, without the need of using synthetic fungicides. Antifungal activity of corn and rice seed-borne mycoflora was tested against aflatoxigenic A. flavus in vitro, using bioassays such as dual culture technique; ability to produce volatile and non-volatile metabolites; ability to inhibit germination and reduce germ tube length of A. flavus conidia; in vivo reduction of aflatoxins level in corn seeds co-inoculated with the pathogen and antagonists. Penicillum crustosum, Aspergillus giganteus, Fusarium verticillioides and Aspergillus fumigatus isolates showed promising antifungal activities and varying efficiencies of reducing aflatoxins level; however, only A. fumigatus isolate was non-aflatoxigenic. It could be concluded that A. fumigatus could be used effectively as a biopreservative to increase shelf life of cereals during storage, but after testing its tendency to produce other mycotoxins or causing human Aspergillosis

    Multirate Ripple-Free Deadbeat Control

    Get PDF
    The design of multirate ripple-free deadbeat controllers is a complex and difficult task. The ripple-free deadbeat control problem can be solved using two approaches, the time domain approach and the polynomial approach. The time domain approach depends on a minimum energy solution and solves the problem in a state space setting. The polynomial approach depends on the solution of the Diophantine equation and solves the problem in a transfer function setting. One approach which has shown promise for solving multirate ripple-free deadbeat control (MRFDC) problems is the use of Diophantine equation parameters. This thesis proposes a hybrid two degree of freedom controller for the fixed-order constrained optimization problem addressing performance and robustness specifications utilizing the parameters of Diophantine equation to build a multirate ripple-free deadbeat control (MRFDC). The salient feature of the proposed approach is that it combines the concept of multirate input which was demonstrated by Salgado and Oyarzun and use this concept in the single rate which was demonstrated by Paz. This research discusses the single rate input, then it proposes the multirate input using the parameterization of the Diophantine equations. Simulation results show that the output signal tracks the input sinusoidal signal in short settling time either in single rate or multirate ripple – free deadbeat control. The time domain specification for the output signal, control signal, error signal and the output of the filter signal are computed and satisfied that it was guaranteed the requirement and constraint

    The Omani Sultanate of Zanzibar between Unity and Separation for the Period between (1223-1275 AH/ 1806-1861 A)

    Get PDF
           Sultan Said bin Sultan bin Ahmed bin Said Al-Busaidi (1223-1273 AH / 1806-1856 AD) was able to rule Oman and Zanzibar in a unified Arab-African state during his reign. However, it was separated for several reasons. Thus, the study aims to clarify the efforts made by Sultan Said for annexing Zanzibar to Oman, establishing the Arab-African Sultanate, and shedding light on the role played by Britain in dividing the Arab-African Sultanate and separating Zanzibar from the Omani rule in (1275 AH-1861 AD). The study has adopted the historical descriptive analytical approach. The study has reached several conclusions, such as: The economic motivators  are the most important factors that push Sultan Said to move his capital from Muscat to Zanzibar in 1832 AD, and settle there until 1840 AD. At that time, Sultan Said bin Sultan laid the necessary foundations and pillars for the advancement of the unified Arab-African Sultanate. Further, he signed several agreements with some European countries to revive trade in the Sultanate. The study has finally recommended to: pursue the interest in the history of Oman and Zanzibar, focus on Britain's relationship with Zanzibar during the reign of Sultan Saeed, and on the impact of the political differences among the sons of Sultan Saeed after his death, Majid bin Saeed and Thuwaini bin Saeed on dividing the unified Arab-African Sultanate. It has also recommended to shed more light on the industrial activity in Zanzibar during Sultan Said bin Sultan bin Ahmed bin Said Al-Busaidi’s rule

    Optimization of self-nanoemulsifying formulations for weakly basic lipophilic drugs: role of acidification and experimental design

    Get PDF
    Formulators face great challenges in adopting systematic approaches for designing self-nanoemulsifying formulations (SNEFs) for different drug categories. In this study, we aimed to build-up an advanced SNEF development framework for weakly basic lipophilic drugs, such as cinnarizine (CN). First, the influence of formulation acidification on CN solubility was investigated. Second, formulation self-emulsification in media with different pH was assessed. Experimentally designed phase diagrams were also utilized for advanced optimization of CN-SNEF. Finally, the optimized formulation was examined using cross polarizing light microscopy for the presence of liquid crystals. CN solubility was significantly enhanced upon external and internal acidification. Among the various fatty acids, oleic acid-based formulations showed superior self-emulsification in all the tested media. Surprisingly, formulation turbidity and droplet size significantly decreased upon equilibration with CN. The design was validated using oleic acid/Imwitor308/Cremophor El (25/25/50), which showed excellent self-nanoemulsification, 43-nm droplet size (for CN-equilibrated formulations), and 88 mg/g CN solubility. In contrast to CN-free formulations, CN-loaded SNEF presented lamellar liquid crystals upon 50% aqueous dilution. These findings confirmed that CN-SNEF efficiency was greatly enhanced upon drug incorporation. The adopted strategy offers fast and accurate development of SNEFs and could be extrapolated for other weakly basic lipophilic drugs

    Mineral and heavy metals content in tilapia fish (Oreochromis niloticus) collected from the River Nile in Damietta governorate, Egypt and evaluation of health risk from tilapia consumption

    Get PDF
    This study was conducted to determine heavy metals and trace elements content in tilapia fish collected from three sources in Damietta governorate, Egypt and to evaluate the human health risk due to tilapia consumption. Tilapia samples were collected from two locations in the River Nile stream, tow fish farms and two sluiceways. Health risk assessment was evaluated based on the consumption habits of adult human. The results revealed that all samples vary in elements concentrations. The calculation of human health risk revealed that the consumption of tilapia in the three tested area does not pose any health risk except for Selenium. It could be concluded that consumption of such fish may be a risk for consumers who eat fish more than one time per week. Consequently, precautions should be taken and warning against eating tilapia fish caught from these regions should be announced.This study was conducted to determine heavy metals and trace elements content in tilapia fish collected from three sources in Damietta governorate, Egypt and to evaluate the human health risk due to tilapia consumption. Tilapia samples were collected from two locations in the River Nile stream, tow fish farms and two sluiceways. Health risk assessment was evaluated based on the consumption habits of adult human. The results revealed that all samples vary in elements concentrations. The calculation of human health risk revealed that the consumption of tilapia in the three tested area does not pose any health risk except for Selenium. It could be concluded that consumption of such fish may be a risk for consumers who eat fish more than one time per week. Consequently, precautions should be taken and warning against eating tilapia fish caught from these regions should be announced

    Extrato de Panax ginseng C.A. Meyer neutraliza o stress oxidativo em ratos alimentados com dieta contaminada com multi-micotoxinas

    Get PDF
    The current study was conducted to evaluate the protective effects of Panax ginseng extract (PGE)against the toxicity and oxidative stress in rats fed aflatoxin (AFs) and/or fumonisin (FB)-contaminateddiet. Eighty female Sprague-Dawley rats were divided into eight experimental groups included thecontrol group, the group treated orally with PGE (0.5 mg/kg b.w.) and the groups fed AFs (1.4 mg/kg diet) and/or FB (20 mg/kg b.w.) contaminated diet alone or plus PGE for 11 weeks. Blood, liverand kidney tissue samples were collected at the end of treatment period for biochemical andhistological studies. The results indicated that PGE increased super oxide dismutase (SOD) levelin liver; however, the other parameters were comparable to controls. Animals fed AFs and/or FBcontaminateddiet showed a significant increase in serum biochemical parameters and oxidativestress markers accompanied with a significant decrease in antioxidant parameters levels and asevere histological changes in the liver tissue. These changes were more pronounced in the groupfed AFs plus FB. PGE succeeded to induce a significant improvement in all biochemical parametersand the histological picture towards the control although it did not normalize them. It could beconcluded that PGE is a promise candidate against the exposure to multi-mycotoxins in food.O presente estudo foi conduzido para avaliar os efeitos protetores do extrato de Panax ginseng(PGE) contra a toxicidade e estresse oxidativo em ratos alimentados com aflatoxinas (AFs) e/oudieta contaminada por fumonisina (FB). Oitenta fêmeas de ratos Sprague-Dawley foram divididasem oito grupos experimentais, incluindo o grupo controle, o grupo tratado com PGE oralmente (0,5mg/kg de peso corporal) e os grupos alimentados com as dietas contaminadas de AFs (1,4 dieta mg/kg) e/ou FB (20 mg/kg de peso corporal) isoladas ou com mais PGE durante 11 semanas. Amostrasde sangue, do fígado e do tecido do rim foram recolhidas no final do período de tratamentopara estudos bioquímicos e histológicos. Os resultados indicaram que a PGE aumenta o nível desuperóxido dismutase (SOD) no fígado, no entanto, os outros parâmetros foram comparáveis aosdo grupo controle. Animais alimentados com dieta contaminada por AF e/ou FB mostraram umaumento significativo nos parâmetros bioquímicos séricos e marcadores de estresse oxidativo,acompanhados de uma diminuição significativa nos níveis de antioxidantes e nos parâmetros dealterações histológicas graves no tecido do fígado. Essas alterações foram mais pronunciadas nogrupo alimentado com AFs mais FB. PGE obteve sucesso quanto à introdução de uma melhoriasignificativa em todos os parâmetros bioquímicos e histológicos com relação ao grupo controle,embora não os tenha normalizado. Pode-se concluir que a PGE é uma promissora candidatacontra a exposição às multimicotoxinas em alimentos
    corecore