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Search Results: 1 - 10 of 482672 matches for " Lucien Jean Raymond Meva’a "
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Physicochemical and Thermal Characterization of Dura Palm Kernel Powder as a Load for Polymers: Case of Polyvinyl Chloride  [PDF]
Rolland Djomi, Lucien Jean Raymond Mevaa, Jean Nganhou, Gérard Mbobda, Abel Emmanuel Njom, Yves Didier Modtegue Bampel, Jean-Bosco Saha Tchinda
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.66001
Abstract: This work presents the physical and thermal characterization of the dura palm kernel powder of Cameroon for their use as fillers for polymers composites. The powders of palm kernel were obtained using a percussion grinder mill with an industrial microniser which allowed obtaining a powder less than 50 μm with an apparent density between 0,505 ≤ ρ ≤ 0,680 g/cm3 at 1.56 of relative humidity. The infrared of the powder of palm kernel shows the presence of phenols groups with a large band around 3341 cm-1, -C-H at 2917.02 cm-1 and -C-O at 1040 cm-1 as the main peaks. The polyvinyl chloride of infrared obtained shows the presence of -C-Cl, -CH2 and CH as the mains peaks. The infrared of 12.5% of palm kernel powder with polyvinyl chloride shows an increase of the CH2 and CH bonds and a decrease of the -OH bonds. Thermogravimetric analysis and differential scanning calorimetric analysis of powders, polyvinyl chloride and mixture showed that the mixing powders are intermediate between the polyvinyl chloride and palm kernel powder. The powder decreased the phase temperatures of the mixture from 98.58 to 95 for the glass transition temperature and from 515℃ to 459 for the crystallization temperature. The thermogravimetric curves of palm kernel powder and polyvinyl chloride have showed that these materials lose their different masses in three different phases, and the one of composite (mixture of polyvinyl chloride with 12.5% of palm kernel powder) in two different phases.
Characteristics and Mechanicals Potentials of Wood Adhesives Manufactured with Grasses’ Lignins  [PDF]
Lionel Tapsia Karga, Danwe Raidandi, Noel Konai, Antonio Pizzi, Lucien Mevaa
Journal of Materials Science and Chemical Engineering (MSCE) , 2019, DOI: 10.4236/msce.2019.71004
Abstract: In order to manufacture environmentally friendly particle boards and enhance local resources, the lignins of Sorghum bicolor and Andropogon gayanus characterized using RMN 13C and MALDI TOF have the same structures. They contents Guaiacyl (G), Syringyl (S), p-hydroxyphenylpropane (H) and functional groups of phenols, flavonoids and secondary alcohols. The total phenol content determinated using Folin-Ciocalteu reagent is respectively 20.97 and 15.42 mg eqgallic acid/g of extract. The power of their adhesives is different. The Internal Bond (IB) of particleboards manufactured with these adhesives are respectively 0.37 MPa and 0.41 MPa. These lignins can be used as antioxydants.
Optimization of sawing in wood transformation primary industries
Ra?dandi Danwe,Isaac Bindzi,Lucien Meva'a
Journal of Industrial Engineering and Management , 2012, DOI: 10.3926/jiem.374
Abstract: Purpose: The loss of raw materials in wood cutting industries has reached high proportions (30 to 36% of volume yield, Ngolle Ngolle, 2009). The purpose of this paper is to solve the problem of optimising the production on the basis of the commercial value of the cuts. Design/methodology/approach: In order to tackle this problem, we started with the generalities on the exploitation and the primary conversion of wood in Cameroon. After that, we studied the various methods of cutting and the different products obtained. We then proceeded with the formulation of the log cutting optimisation problem based on a real shape model of the logs, objective of research works presented in (Danwé, Bindzi, Meva’a & Nola, 2011). We finally completed our work with the design and the presentation of a software package called cutting optimiser. Findings: We start by having some knowledge on the geometry of the logs, cutting strategies and classification of cuts. This classification enables us to determine the quality and quantity of the production, and to estimate the commercial value of the log. The solution to this problem then led to the design of a software package. Research limitations/implications: In this paper, the optimisation problem concerns problems where the objective function is non-explicit, the variables discreet, and the constraints non-explicit. Practical implications: The solution to this problem then led to the design of a software package to be used as a cutting optimiser. The automation of the cutting operation leads to an accelerated work and an increase in the volume of the cuts produced daily. Originality/value: This research is among the few to solve discrete optimization problems with constraints. Some constraints concerning the mechanical characteristics of the logs are taken into account. The constraints can equally be non-explicit. Moreover the market standards impose technological constraints which render the problem of optimisation even more complex.
Les lois Bérenger (lois du 14 ao t 1885 et du 26 mars 1891)
Jean-Lucien Sanchez
Criminocorpus, Revue Hypermédia , 2005, DOI: 10.4000/criminocorpus.132
Abstract: La constatation de l’accroissement continu de la récidive délinquante et criminelle tout au long du XIXe siècle a conduit les pénalistes et les criminologues à distinguer les délinquants par habitude ou professionnels, des délinquants par accident ou primaires (Lacassagne A., Martin E., AAC, 1901, p. 540). Les premiers sont considérés comme incorrigibles. Le crime semble être leur état naturel et la pénalité classique ne peut plus rien pour eux, ils sont inamendables et définitivement incor...
L'anthropométrie au service de l'identification des récidivistes : l'exemple de la relégation en Guyane fran aise
Jean-Lucien Sanchez
Criminocorpus, Revue Hypermédia , 2011, DOI: 10.4000/criminocorpus.365
Abstract: Jeune commis à la préfecture de police de Paris, Alphonse Bertillon présente par deux fois en 1879 et en 1881 au préfet Louis Andrieux une méthode de mesure ostéométrique qu'il estime infaillible pour découvrir l'identité de condamnés récidivistes. N'obtenant aucun succès, son initiative suscite néanmoins l'intérêt du nouveau préfet Ernest Camescasse, nommé à la tête de la préfecture au mois de juillet 1881. Il décide d'accorder un délai probatoire à Alphonse Bertillon qui parvient, le 20 fév...
La douloureuse histoire du for at innocent Philibert Gaucher
Jean-Lucien Sanchez
Criminocorpus, Revue Hypermédia , 2011, DOI: 10.4000/criminocorpus.338
Abstract: Le 22 avril 1938, le garde des Sceaux re oit un courrier lui indiquant qu'un ancien transporté accompagné d'un ancien relégué gracié organise des conférences en Vendée et en Charente inférieure. Durant ces conférences, dont l'entrée est de deux francs, l'ex-for at vend des brochures dans lesquelles il dénonce les conditions de vie déplorables qu'il a subies à Fontevrault et au dép t de Saint-Martin-de-Ré et clame contre l’injustice dont il a été victime. Le procureur général près la cour d'ap...
La relégation (loi du 27 mai 1885)
Jean-Lucien Sanchez
Criminocorpus, Revue Hypermédia , 2005, DOI: 10.4000/criminocorpus.130
Abstract: La loi du 27 mai 1885 (lire le texte), dite loi sur la relégation des récidivistes, entra ne l’internement perpétuel sur le territoire des colonies ou possessions fran aises des délinquants et criminels multirécidivistes . L’enjeu de cette loi est de débarrasser le sol de la France métropolitaine des petits délinquants et vagabonds par une mécanique qui est unique dans l’histoire du droit pénal fran ais. En effet, cette loi établie une présomption irréfragable d’incorrigibilité , c...
Population-Based Monitoring of Emerging HIV-1 Drug Resistance on Antiretroviral Therapy and Associated Factors in a Sentinel Site in Cameroon: Low Levels of Resistance but Poor Programmatic Performance
Serge C. Billong, Joseph Fokam, Avelin F. Aghokeng, Pascal Milenge, Etienne Kembou, Ibile Abessouguie, Flore Beatrice Mevaa-Onglene, Anne C. Zoung-Kanyi. Bissek, Vittorio Colizzi, Eitel N. Mpoudi, Jean-Bosco N. Elat, Koulla S. Shiro
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0072680
Abstract: Background Scale-up of antiretroviral therapy (ART) in resource-limited settings has drastically reduced HIV-related morbidity and mortality. However, challenges in long-term ART, adherence and HIV drug resistance (HIVDR) itself, require monitoring to limit HIVDR emergence among ART-experienced populations, in order to ensure regimen efficacy. Methods A longitudinal study was conducted from 2009–2011 in a cohort of 141 HIV-infected adult patients (aged >21) at the national social insurance centre hospital in Yaounde, Cameroon. As per-WHO HIVDR protocol, HIV-1 protease-reverse transcriptase genotyping was performed at baseline and at endpoint (12 months) on first-line ART using ViroSeq? Genotyping kit. Results At baseline, a prevalence of 3.6% (5/139) HIVDR was observed [protease inhibitors M46I (1/5), G73A (1/5), L90LM (1/5); nucleoside reverse transcriptase inhibitors: M184V (1/5), T215F (1/5); non-nucleoside reverse transcriptase inhibitors: K103N (1/5), Y181Y/C (2/5), M230ML (1/5)]. At endpoint, 54.0% (76) patients were followed-up, 9.2% (13) died, and 3.5% (5) transferred, 38.5% (47) lost to follow-up (LTFU). 69.7% (53/76) of those followed-up had viremia <40 copies/ml and 90.8% (69/76) <1000 copies/ml. 4/7 patients with viremia ≥1000 copies/ml harbored HIVDR (prevalence: 5.3%; 4/76), with M184V/I (4/4) and K103K/N (3/4) being the most prevalent mutations. LTFU was favored by costs for consultation/laboratory tests, drug shortages, workload (physician/patient ratio: 1/180) and community disengagement. Conclusions Low levels of HIVDR at baseline and at endpoint suggest a probable effectiveness of ART regimens used in Cameroon. However the possible high rate of HIVDR among LTFUs limited the strengths of our findings. Evaluating HIVDR among LTFU, improving adherence, task shifting, subsidizing/harmonizing costs for routine follow-up, are urgent measures to ensure an improved success of the country ART performance.
Virtualizing the p-ANAPL Library: A Step towards Drug Discovery from African Medicinal Plants
Fidele Ntie-Kang, Pascal Amoa Onguéné, Ghislain W. Fotso, Kerstin Andrae-Marobela, Merhatibeb Bezabih, Jean Claude Ndom, Bonaventure T. Ngadjui, Abiodun O. Ogundaini, Berhanu M. Abegaz, Luc Mbaze Mevaa
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090655
Abstract: Background Natural products play a key role in drug discovery programs, both serving as drugs and as templates for the synthesis of drugs, even though the quantities and availabilities of samples for screening are often limitted. Experimental approach A current collection of physical samples of > 500 compound derived from African medicinal plants aimed at screening for drug discovery has been made by donations from several researchers from across the continent to be directly available for drug discovery programs. A virtual library of 3D structures of compounds has been generated and Lipinski’s “Rule of Five” has been used to evaluate likely oral availability of the samples. Results A majority of the compound samples are made of flavonoids and about two thirds (2/3) are compliant to the “Rule of Five”. The pharmacological profiles of thirty six (36) selected compounds in the collection have been discussed. Conclusions and implications The p-ANAPL library is the largest physical collection of natural products derived from African medicinal plants directly available for screening purposes. The virtual library is also available and could be employed in virtual screening campaigns.
Modeling the wait time of a hierarchical system: Case study of an Internal Medicine unit
L. MEVAA,,R. DANWE,J. NGANHOU
International Journal of Engineering and Technology , 2011,
Abstract: All, such as industrial production (Manufacturing companies), health units are hierarchical at the level of organization. This arrangement permits them to response efficiently to an event in occurrence, such as a patient whom appropriate care has to be dispensed. The quick reaction of the medical unit when faced with a problem is not only an indicator of its reactivity, but also an indicator of its performance.In this article, we propose to model the reaction of a medical unit in relationship to parameters, notably the reference periods of the different levels at which decisions are made. We define and express subsequently, the wait times which is a source of delay in the treatment process of a patient from when he arrives. Then, we propose an algorithm which minimizes the wait time.
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