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Production and Characterization of High Density Polyethylene Reinforced by Eucalyptus Capsule Fibers

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Journal of Bionic Engineering 2018年第3期15卷 558-566页

作者： Wafa Ouarhim Mohammed-Ouadi Bensalah denis rodrigue Hamid Essabir Rachid Bouhfid Abou el kacem Qaiss Moroccan Foundation for Advanced Science Innovation and Research (MAScIR) Institute of Nanomaterials and Nanotechnology (NANOTECH) Laboratory of Polymer Processing Rabat Morocco Faculty of Science Laboratory of Mechanic and Materials (LMM) Mohammed V-Rabat University Rabat Morocco Department of Chemical Engineering and CERMA Universite Laval Quebec G1V0A6 Canada

In this work, Eucalyptus Capsule Fibers （ECF） are proposed as a new natural fiber reinforcement to produce bio-composites due to their biological origin, specific smell and color. High Density Polyethylene （HDPE） is used as the matrix to compare three reinforcement types, raw ECF, alkali treated ECF, and ECF treated with PE-graft-maleic anhydride （PE-g-MA） as a coupling agent at three concentrations （5 wt.%, 10 wt%, and 15 wt%）. A complete set of characterization is performed including tension, torsion, hardness, Melt Flow Index （MFI）, Attenuated Total Reflection Fourier Transform Infrared Spectroscopy （ATR-FTIR）, Contact Angle （CA）, Scanning Electron Microscopy （SEM）, Thermogravimetric Analysis （TGA） and Dynamic Mechanical Analysis （DMA）. The results show that the best mechanical and rheological improvements are obtained by using the coupling agent with alkali treated fibers.

关键词： eucalyptus capsule fibers polyethylene alkaline treatment coupling agent mechanical properties

A Comparison between Sabra and Alfa Fibers in Rubber Biocomposites

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Journal of Bionic Engineering 2019年第4期16卷 754-767页

作者： Wafa Ouarhim Hamid Essabif Mohammed-Ouadi Bensalah denis rodrigue Rachid Bouhfid Abou el kacem Qaiss Moroccan Foundation for Advanced Science Innovation and Research(MAScIR)Composites and Nanocomposites Center(CNC)Rabat 10100Morocco Faculty of Science Laboratory of Mechanic and Materials(LMM)Mohammed V-RabatUniversityRabat 10100Morocco National School of Applied Science(ENSA) Ibn Zohr University-AgadirAgrandir 80000Morocco Department of Chemical Engineering and CERMA Universite LavalQuebec G1V0A6Canada

The main objective of this investigation is to valorize a Moroccan crop residue(Sabra fibers,Agave Americana L.)and to compare with Alfa fibers(,Stipa tenacissima L.)as reinforcement in an elastomeric matrix in term of the relaxation properties,mechanical and rheological *** preparation and properties of these two natural fibers embedded in Styrene-Butadiene Rubber(SBR)are presented with and without the addition of Styrene-Ethylene-Butadiene-Styrene grafted with Maleic Anhydride(SEBS-g-MA)as a coupling *** different series(SBR,SBR/Alfa,SBR/Alfa/SEBS,SBR/Sabra and SBR/Sabra/SEBS)were compounded by extrusion and compression *** a result,the addition of the coupling agent in the elastomeric matrix improves the relaxation properties,mechanical and rheological ***,Sabra fibers show the good results compared to Alfa ***,the Zener model was used to determine the rheological time response of the composites.A good agreement between the experimental data and the model was observed(R^2=0.99).

关键词： Sabra fibers Alfa fibers SBR biocomposite relaxation mechanical and rheological properties Zener model

Elastic modulus prediction for hybrid polymer composites

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Materials Engineering Research 2019年第2期1卷 64-68页

作者： denis rodrigue College of Chemistry and Material Engineering Hunan University of Arts and ScienceChangde 415000China Department of chemical engineering Universit′e LavalQuebecG1V0A6Canada

To improve on the mechanical properties of polymers in general, the concept of hybrid composites was developed by using two or more different reinforcements in the same matrix, or by using two or more different sizes of the same reinforcement (auto-hybrid composites). In this case, most of the literature results showed that the resulting elastic modulus can be well approximated by the simple rule of mixture (linear additive law) from the tensile modulus of each reinforcement used alone. But is some cases, a positive deviation from this linear approximation was reported up to a point where an optimum composition can give a modulus above the value of both reinforcements used separately. In this work, a simple model is presented to show that positive deviations are possible and the optimum reinforcement ratio is around 25/75 in terms of the lowest/highest reinforcing particle. The model is also compared with literature data where good qualitative agreements are obtained as a first approximation.

关键词： hybrid polymer composites elastic modulus optimum composition

Reinforcement of Lignin-Based Phenol-Formaldehyde Adhesive with Nano-Crystalline Cellulose (NCC): Curing Behavior and Bonding Property of Plywood

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Materials Sciences and Applications 2015年第6期6卷 567-575页

作者： Zhenbo Liu Yaolin Zhang Xiangming Wang denis rodrigue Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education) & Northeast Forestry University Harbin China FPInnovations-Wood Products Quebec Canada Department of Chemical Engineering Laval University Quebec Canada

The curing behavior of lignin-based phenol-formaldehyde (LPF) resin with different contents of nano-crystalline cellulose (NCC) was studied by differential scanning calorimetry (DSC) at different heating rates (5, 10 and 20°C/min) and the bonding property was evaluated by the wet shear strength and wood failure of two-ply plywood panels after soaking in water (48 hours at room temperature and followed by 1-hour boiling). The test results indicated that the NCC content had little influence on the peak temperature, activation energy and the total heat of reaction of LPF resin at 5 and 10°C/min. But at 20°C/min, LPF0.00% (LPF resin without NCC) showed the highest total heat of reaction, while LPF0.25% (LPF resin containing 0.25% NCC content) and LPF0.50% (LPF resin containing 0.50% NCC content) gave the lowest value. The wet shear strength was affected by the NCC content to a certain extent. With regard to the results of one-way analysis of variance, the bonding quality could be improved by NCC and the optimum NCC content ranged from 0.25% to 0.50%. The wood failure was also affected by the NCC content, but the trend with respect to NCC content was not clear.

关键词： Lignin-Based Phenol-Formaldehyde Resin (LPF) Nano-Crystalline Cellulose (NCC) Curing Behavior Bonding Properties Plywood

Microcellular Agave Fibre-High Density Polyethylene Composites Produced by Injection Molding

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材料科学与工程（中英文A版） 2012年第11期2卷 677-692页

作者： Cedric Tissandier Roberto Carlos Vazquez Fletes Ruben Gonzalez-Nunez denis rodrigue Departement de Genie Chimique Universite Laval Quebec G1 V OA6 Canada Departamento de Ingenierla Quimica Universidad de Guadalajara Guadalajara 44430 Mexico

In this study, microcellular high density polyethylene-agave fibre composites were produced using a chemical foaming agent (azodicarbonamide). The samples were injection molded with the objective to produce symmetric and asymmetric structures. To this end, the temperatures of both parts of the mold were independently controlled. From the samples produced, a complete morphological and mechanical characterization was performed. As expected, composite density increased with fibre content and decreased with foaming agent content. Young"s modulus was found to increase, but strain at break decreased with increasing agave content. Moreover, Young"s modulus and strain at break both decreased with increasing foaming agent content. Actually, the microcellular foams were found to have a different tensile behavior than their natural fibre-reinforced counterparts. Considering the experimental results obtained, natural fibre-reinforced microcellular foams present interesting properties for different technical applications.

关键词：聚乙烯复合材料高密度聚乙烯纤维复合材料微孔泡沫龙舌兰生产注塑天然纤维增强

Prediction of the severity of colorectal lesion by fecal hemoglobin concentration observed during previous test in the French screening program

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World Journal of Gastroenterology 2021年第31期27卷 5272-5287页

作者： Christian Balamou Akoi Koivogui Christelle M rodrigue Aurelie Clerc Claire Piccotti Anne Deloraine Catherine Exbrayat Site de l'Ain Centre Régional de Coordination des Dépistages des Cancers en Auvergne-Rhône-AlpesBourg-en-Bresse 01000France Site de Seine-Saint-denis Centre Régional de Coordination des Dépistages des Cancers en Ile-de-FranceBondy 93146France Sites Savoie&Haute Savoie Centre Regional de Coordination des Depistages des Cancers en Auvergne-Rhone-AlpesChambery 73000France Site de Drome Ardeche Centre Regional de Coordination des Depistages des Cancers en Auvergne-Rhone-AlpesValence 26000France Site Isere&Drome-Ardeche Centre Regional de Coordination des Depistages des Cancers en Auvergne-Rhone-AlpesMeylan 38240France

BACKGROUND The rate of positive tests using fecal immunochemical test(FIT)does not decrease with subsequent campaigns,but the positive predictive value of advanced neoplasia significantly decreases in subsequent campaign after a first negative test.A relationship between the fecal hemoglobin concentration(Fhb)and the opportunity to detect a colorectal cancer in subsequent campaign has been *** To predict the severity of colorectal lesions based on Fhb measured during previous colorectal cancer screening *** This etiological study included 293750 patients aged 50-74,living in Auvergne-Rhone-Alpes(France).These patients completed at least two FIT[test_((-1))and test_((0))]between June 2015 and December *** between test_((-1))and test_((0))was>1year and test_((-1))result was negative(<150 ngHb/mL).The severity of colorectal lesions diagnosed at test_((0))was described according to Fhb measured at test_((-1))[Fhb_((-1))].The relationship between the severity classified in seven ordinal categories and the predictive factors was analyzed in an ordered multivariate polytomous regression *** The test_((0))positive rate was 4.0%,and the colonoscopy completion rate was 97.1%in 11594 patients who showed a positive test_((0)).The colonoscopy detection rate was 77.7%in those 11254 patients who underwent a colonoscopy.A total of 8748 colorectal lesions were detected(including 2182 low-risk-polyps,2400 high-riskpolyp,and 502 colorectal cancer).The colonoscopy detection rate varied significantly with Fhb_((-1))[0 ngHb/mL:75.6%,(0-50 ngHb/mL):77.3%,(50-100 ngHb/mL):88.7%,(100-150 ngHb/mL):90.3%;P=0.001].People with a Fhb_((-1))within(100-150 ngHb/mL)(P=0.001)were 2.6(2.2;3.0)times more likely to have a high severity level compared to those having a Fhb_((-1))value of *** risk was reduced by 20%in patients aged 55-59 compared to those aged<55[adjusted odds ratio:0.8(0.6;1.0)].CONCLUSION The study showed that higher Fhb_((-1))is correlated to

关键词： Colorectal cancer screening Fecal immunochemical test Fecal hemoglobin concentration Colorectal lesion severity

Pancreatic Cancer: Epidemiological, Clinical and Therapeutic Aspects in Abidjan (Ivory Coast)

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Open Journal of Gastroenterology 2017年第8期7卷 223-229页

作者： Amadou Ouattara Siaka Kone Dramane Soro Constant Assi Emile Allah-Kouadio rodrigue Irie Gohi Bi Fanoucoffi denis Marie-Jeanne Lohoues-Kouacou Teaching Hospital Center of Cocody Abidjan C&ocirc te d’Ivoire

Aim: The aim was to study the epidemiological, clinical and therapeutic aspects of pancreatic cancers in Ivory Coast. Materials and methods: A retrospective multi-center and multidisciplinary study aimed at describing sixteen years and four months from January 1, 2000 to April 30, 2016 in several hospitals in the city of Abidjan taking charge of pancreatic cancers (hepato-gas troenterology services of the universities hospitals of Cocody and Yopougon), internal medicine departments of University Hospital of Treichville and Abidjan Military Hospital, the department of oncology of the university hospital center of Treichville, private clinics (DANGA, PISAM and GMP), the COBA center in Treichville. The diagnosis of cancer was based on either histological criteria or a set of clinical and paraclinical arguments. Patients whose files did not include imaging were excluded from this study. The following parameters were collected: age, sex, reason for consultation, physical signs, personal and family antecedents, tumor characteristics, delay in diagnosis and the nature of the treatment administered. Results: We have observed 150 cases of pancreatic cancer. The mean age of patients was 59.09 years with extremes ranging from 24 years to 88 years. Our study population consisted of 98 men and 52 women (sex ratio 1.88). Risk factors were dominated by diabetes 20.7%. Epigastralgia is the main reason for consultation (48%). The tumor was localized at the cephalic level in 84.67%. In 13 cases the diagnosis was histological and was dominated by adenocarcinoma (100%). The majority of our patients was seen at an advanced stage of the disease: stage IV (74.56%). The average time to diagnosis was 2.76 months. Fourteen of our patients (9.33%) had benefited surgery. This was curative surgery in 35.71% (n = 5) and palliative in 64.29% (n = 9). Among those who benefited from this curative surgery, three died two months after surgery and two lost to follow-up. The majority (90.67%) of our pa

关键词： Pancreas Cancer Epidemiological Ivory Coast

Microstrip Leaky-Wave Antenna for Radar Applications

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Open Journal of Antennas and Propagation 2024年第2期12卷 19-29页

作者： Ronelle Rudaï Gochincka Gogom Charmolavy Goslavy Lionel Nkouka Moukengue Brice rodrigue Malonda-Boungou Electrical and Electronic Engineering Laboratory ENSP Marien Ngouabi University Brazzaville Congo Groupe de Simulations Numriques en Magntisme et Catalyse Facult des Sciences et Techniques Universit Marien Ngouabi Brazzaville Congo Institut National de Recherches en Sciences Exactes et Naturelles (IRSEN) Brazzaville Congo Facult des Sciences Appliques Universit Denis Sassou-Nguesso Kintl Congo

The work in this article focuses on developing and improving the performance of new leaky-wave antenna configurations that can be adapted for use in radar systems. The study focused on the W-band, where we demonstrated the possibility of modifying resonant frequencies and reducing the number of patches required. The antenna was designed using HFSS, based on the finite element method. It we designed enabled us to observe the influence of the number of patches on the radiation pattern, and also to achieve low levels of minor’s lobes. and good directivity at the operating frequency. These patches are arranged in the shape of an inverted T. The interest of this study is to meet the requirements of radar antennas dedicated to detection.

关键词： Leaky-Wave Antenna Microstrip HFSS Radar Applications