Fluidization of cohesive nanoparticles with a new pulsation technique

The nanoparticles are building block of many advanced materials that are developed for a variety of industries. Fluidization of the nanoparticles can improve dramatically quality of the final material in processes such as coating, drying and crystallization because of enhanced mixing conductions in a fluidized bed. However, due to severe presence of interparticle forces, the nanoparticles are very cohesive, and thus their fluidization is impossible with conventional methods. Authors developed a novel pulsation-assisted technic to effectively fluidize the nanoparticles of different types. The developed fluidization technic was primarily investigated inside a transparent tube with 2.5 cm diameter and 20 cm height. A solenoid valve was located in the reactor outlet to switch between ON and OFF positions to intermittently pressurize the gas inside the reactor and then let it exit. Two differential pressure transducers and a high-speed camera recorded the pressure fluctuations of the bed. Superficial gas velocity and intermittence frequency of the solenoid valve were varied to investigate fluidization quality. An experimental procedure was developed to estimate the maximum amount of interparticle forces between the nanoparticles in the bed. Investigations showed under optimum conditions when the solenoid valve was open an upward lift force was generated that helped fluidize the bed. The lift force was greater than sum of the bed weight and the maximum interparticle forces minus the drag force. Bed fluctuations were examined at temperatures 650, 700 and 750 °C, and it was revealed that the developed technique could be optimized to work at such temperatures

Les déterminants de la confiance/méfiance du consommateur marocain vis-à-vis du cyber-achat

Cet article propose une étude empirique des déterminants de la confiance vs. méfiance des consommateurs marocains à l’égard du cyberachat. Ce secteur peine à se développer au Maroc en raison de plusieurs facteurs, notamment l’absence de compétences numériques, la fiabilité des vendeurs en ligne et la faiblesse d’un cadre législatif protégeant les intérêts des consommateurs en ligne. C’est dans ce cadre que se situe ce papier. Un questionnaire a été administré auprès de 2254 individus localisés dans trois villes marocaines différentes. Une analyse factorielle multidimensionnelle a relevé l’existence d’une méfiance envers l’achat en ligne chez les marocains due à plusieurs facteurs. De plus, cette étude a permis de classer les individus en trois groupes selon les variables les plus discriminantes : « Les cyberconsommateurs confiants » qui achètent sans réserve, les « cyberconsommateurs méfiants » qui achètent en ligne mais qui pensent être conscients du danger que représente l’achat virtuel et les « nonconsommateurs » présentant une aversion au commerce électronique. This article proposes an empirical study of the determinants of trust vs. distrust of Moroccan consumers towards e-commerce. This sector is struggling to develop in Morocco due to several factors, including the lack of digital skills, the reliability of online sellers and a weakness of legislative framework protecting the interests of online consumers. It is against this background that our contribution is situated. We opted for an empirical approach by administering a survey to 2254 individuals located in three different Moroccan cities. A multidimensional factorial analysis revealed the existence of a mistrust towards e-commerce among Moroccans due to several factors. In addition, this study allowed us to classify individuals into three groups according to the most discriminating variables: "Confident cyber-consumers", "mistrustful cyber-consumers" and "online non-shoppers" with an aversion to e-commerce

LE CADRE JURIDIQUE DU CROWDFUNDING : CAS DU MAROC

   Le crowdfunding (financement collaboratif) permet aux entrepreneurs voulant lancer des startups, des entreprises ou des associations de trouver des financements auprès du public à travers des plateformes digitales via internet.    Au Maroc, le crowdfunding est dans une phase embryonnaire mais peut s’adapter aux enjeux de développement humain, social et économique. L’adoption récente de la Loi n°15-18 relative au financement collaboratif pourrait permettre de voir l’écosystème du crowdfunding se développer.    Ce travail de recherche a pour objectif de comparer le cadre juridique du crowdfunding au Maroc avec les exigences réglementaires appliquées dans d’autres pays. La première partie de ce travail portera sur le concept de crowdfunding, ses modalités, ses acteurs, l’état des lieux du crowdfunding au Maroc et son développement dans le monde. La deuxième partie s’intéressera à l’importance de l’existence d’un cadre juridique pour le développement des opérations de financement collaboratif et mettra en exergue le cadre juridique du crowdfunding au Maroc.   La méthodologie suivie pour l’élaboration de cet article est basée sur l’analyse des données de type secondaire à partir de textes de la loi marocaine, d’articles et de rapports traitant le crowdfunding au Maroc et dans le reste du monde.Abstract:    Crowdfunding allows entrepreneurs wanting to launch startups, companies, associations to raise funds from the public through digital platforms via the internet.    In Morocco, crowdfunding is at an embryonic stage, but can be adapted to the challenges of human, social and economic development. The recent adoption of law n°15-18 on crowdfuding could help the crowdfunding ecosystem to develop.      This research work aims to compare the legal framework of crowdfunding in Morocco with the regulatory requirements applied in other countries. The remainder of this article is organized as follows: the first part of this work will focus on the concept of crowdfunding, its modalities, its actors, the state of crowdfunding in Morocco and its development in the world. The second part will focus on the importance of a legal framework for the development of different types of crowdfunding operations and will highlight the legal framework in Morocco.   The methodology used for this research work is based on the analysis of secondary type data from Moroccan law texts, articles and reports dealing with crowdfunding in Morocco and in the rest of world

Gas-phase carbon coating of LiFePO4 for rechargeable batteries

Lithium iron phosphate (LFP) powder is the building block material of cathode of the rechargeable lithium ion batteries. LFP has received a lot of interest due to its key advantages such as thermal stability, environmental friendly and potential of low cost. Despite these advantages, LFP suffers from low conductivity and low diffusion. Achieving small size particles and applying a carbon-coating layer commonly address these limitations. The coating also affords longer cycle life to the rechargeable batteries. However, traditional LFP carbon coating is achieved from a liquid (e.g. dissolved sugar)- or solid-phase process (e.g. co-polymer); therefore, there have been issues such as high cost, excess carbon (dead weight), non uniform layer and undesired type of the coated carbon. We developed a gas-phase carbon coating process to coat LFP powders with a thin layer of carbon at elevated temperature (700 and 750°C) and different reaction times in a fluidized bed reactor using gaseous hydrocarbons as a carbon source. The coating technique consisted of feeding mixture of propylene in nitrogen as carbon precursor to the preheated reactor containing fluidized LFP powder (agglomerates). Characterization of the coated LFP was achieved by XRD, SEM, TEM, XPS and LECO. The influence of the key operating parameters was investigated. The results show that under optimal conditions, the primary particles of LFP are uniformly coated while the original structure of the LFP remained unchanged. In addition, XPS analyses reveal that a strong bond is formed between the deposited carbon and the phosphate of LFP

Evaluation of RANKL/OPG Serum Concentration Ratio as a New Biomarker for Coronary Artery Calcification: A Pilot Study

Objective. There is a strong need for biomarkers to identify patients at risk for future cardiovascular events related with progressive atherosclerotic disease. Osteoprotegerin (OPG) protects the skeleton from excessive bone resorption by binding to receptor activator of nuclear factor-κB ligand (RANKL) and preventing it from binding to its receptor, receptor activator of nuclear factor-κB. However, conflicting results have been obtained about association of serum level of OPG or RANKL with coronary artery disease (CAD). Based on their role in inflammation and matrix degradation and the fact that atherosclerotic plaque formation is an inflammatory process, we hypothesized that RANKL : OPG ratio could be a better biomarker for CAD. Methods. In this cross-sectional study, the correlation between RANKL : OPG ratio serum concentration and coronary artery calcification (CAC) in 50 patients with ischemic coronary disease has been investigated. We used ELISA method for measuring RANKL and OPG serum concentrations. Results. There was a significant correlation between RANKL : OPG serum concentration ratio and CAC in our study population (P = 0.01). Conclusion. Our results suggested that RANKL : OPG ratio concentration has a potential of being used as a marker for coronary artery disease

Diabetes and hypertension in patients with psoriasis: a cross sectional and case control study in a tertiary care hospital of Bangladesh

Background: In this study our main goal was to evaluate the association of psoriasis as a risk predictor for the occurrence of diabetes mellitus (DM) and hypertension (HTN).Methods: This case control study was carried out in the department of dermatology and venereology, Chittagong medical college hospital (CMCH), Chittagong, Bangladesh from 15 June 2011 to 14 May 2012. Where 60 patients with psoriasis and 60 patients with skin diseases other than psoriasis were included according to availability within the study period.Results: During study, among the psoriatic patients, most of the patients with DM and HTN had body mass index (BMI) within normal limit. During analysis of different clinical findings in psoriatic patients scaling was present in all the cases followed by Auspitz sign, koebnerization, itching, scalp involvement and nail changes. Patients with psoriasis were found to have higher incidence of DM and HTN in comparison to their non-psoriatic control group. It was also observed that psoriatic patients having DM and HTN had longer duration of diseases (p<0.05).Conclusions: In conclusion, our study indicates that patients with psoriasis have an increased risk of DM and HTN, confirming the findings from previous several case control and cross sectional studies. These data illustrate the importance of considering psoriasis as a systemic disorder rather than simply a skin disease. Awareness of concurrent diseases will provide the clinician an opportunity of screening .for others systemic diseases

Assessing Diagnosis of Candida Infections: A Study on Species Prevalence and Antifungal Resistance in Northern Morocco

Gabaldón, Ton

Bio-expert : Knowledge Management Platform and Experiment for Bio-Medical e-Learning

Colloque avec actes et comité de lecture. internationale.International audiencebio-expert project has been launched to cover user needs in terms of access to high level knowledge content with a user friendly interface tool. The problematic raised here concerns not only imaging technologies, knowledge management system and interfaces but also the organisation of the content allowing an easy access of the repository to the community of biologists