WorldWideScience

Sample records for cellulose pour applications

  1. Synthesis and study of nano-structured cellulose acetate based materials for energy applications; Synthese et etude de materiaux nanostructures a base d'acetate de cellulose pour applications energetiques

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, F

    2006-12-15

    Nano-structured materials have unique properties (high exchange areas, containment effect) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO{sub 2} supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nano-materials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a poly-functional iso-cyanate. The dry materials obtained after solvent extraction with supercritical CO{sub 2} are nano-structured and mainly meso-porous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultra-porous reference aerogel, with a density equals to 0,245 g.cm{sup -3} together with a meso-porous volume of 3,40 cm{sup 3}.g{sup -1} was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W.m{sup -1}.K{sup -1}. In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nano-structured and nano-porous, even if important structural modifications have occurred during the carbonization process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels). (author)

  2. Cellulose nanocrystals: synthesis, functional properties, and applications

    Directory of Open Access Journals (Sweden)

    George J

    2015-11-01

    Full Text Available Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers are biodegradable and renewable in nature and hence they serve as a sustainable and environmentally friendly material for most applications. These nanocrystals are basically hydrophilic in nature; however, they can be surface functionalized to meet various challenging requirements, such as the development of high-performance nanocomposites, using hydrophobic polymer matrices. Considering the ever-increasing interdisciplinary research being carried out on cellulose nanocrystals, this review aims to collate the knowledge available about the sources, chemical structure, and physical and chemical isolation procedures, as well as describes the mechanical, optical, and rheological properties, of cellulose nanocrystals. Innovative applications in diverse fields such as biomedical engineering, material sciences, electronics, catalysis, etc, wherein these cellulose nanocrystals can be used, are highlighted. Keywords: sources of cellulose, mechanical properties, liquid crystalline nature, surface modification, nanocomposites 

  3. Cellulosic Bionanocomposites: A Review of Preparation, Properties and Applications

    OpenAIRE

    Alain Dufresne; Gilberto Siqueira; Julien Bras

    2010-01-01

    Cellulose is the most abundant biomass material in nature. Extracted from natural fibers, its hierarchical and multi-level organization allows different kinds of nanoscaled cellulosic fillers—called cellulose nanocrystals or microfibrillated cellulose (MFC)—to be obtained. Recently, such cellulose nanoparticles have been the focus of an exponentially increasing number of works or reviews devoted to understanding such materials and their applications. Major studies over the last decades have s...

  4. Cellulose nanocrystals: synthesis, functional properties, and applications

    OpenAIRE

    George J.; Sabapathi SN

    2015-01-01

    Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers...

  5. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors

  6. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiapeng, E-mail: firgexiao@sina.cn; Pang, Zengyuan, E-mail: pangzengyuan1212@163.com; Yang, Jie, E-mail: young1993@126.com; Huang, Fenglin, E-mail: flhuang@jiangnan.edu.cn; Cai, Yibing, E-mail: yibingcai@jiangnan.edu.cn; Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn

    2015-09-15

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors.

  7. Chemical modification of cellulose for electrospinning applications

    OpenAIRE

    Martín Ferrer, Elena

    2013-01-01

    The aim of the thesis is to develop technology for producing cellulose fatty acid esters that later will be used to produce fibrous materials by means of electrospinning. Main material of the study is cellulose-stearate which is a polymer synthesised by reaction between stearoyl chloride and cellulose. The experimental part consists of synthesis of it by chemical modification of cellulose using ionic liquid as a reaction media. In addition, ionic liquid is also synthesised from the beginning....

  8. Cellulose

    Science.gov (United States)

    Cellulose properties and structure are reviewed, with a primary focus on crystal structure and polymorphy. This focus highlights the conversion from cellulose I to cellulose II, which converts the molecules to being all parallel to each other in the crystal to being antiparallel. This has been co...

  9. Cellulosic Bionanocomposites: A Review of Preparation, Properties and Applications

    Directory of Open Access Journals (Sweden)

    Alain Dufresne

    2010-12-01

    Full Text Available Cellulose is the most abundant biomass material in nature. Extracted from natural fibers, its hierarchical and multi-level organization allows different kinds of nanoscaled cellulosic fillers—called cellulose nanocrystals or microfibrillated cellulose (MFC—to be obtained. Recently, such cellulose nanoparticles have been the focus of an exponentially increasing number of works or reviews devoted to understanding such materials and their applications. Major studies over the last decades have shown that cellulose nanoparticles could be used as fillers to improve mechanical and barrier properties of biocomposites. Their use for industrial packaging is being investigated, with continuous studies to find innovative solutions for efficient and sustainable systems. Processing is more and more important and different systems are detailed in this paper depending on the polymer solubility, i.e., (i hydrosoluble systems, (ii non-hydrosoluble systems, and (iii emulsion systems. This paper intends to give a clear overview of cellulose nanoparticles reinforced composites with more than 150 references by describing their preparation, characterization, properties and applications.

  10. Fabrication of Piezoelectric Cellulose Paper and Audio Application

    Institute of Scientific and Technical Information of China (English)

    Jung-Hwan Kim; Sungryul Yun; Joo-Hyung Kim; Jaehwan Kim

    2009-01-01

    We report the fabrication process of piezoelectric cellulose paper and the enhancement method of its piezoelectric property.Stretching method with different wet-drawing ratios was introduced to increase the piezoelectric property of cellulose paper during regeneration process. It is observed that the Young's modulus and the piezoelectric charge constants are very dependent on the drawing ratio and the direction of nanofibrils of piezoelectric paper. Using the enhanced piezoelectric property, we prove that the flexible regenerated piezoelectric cellulose can be applied to the potential acoustic applications such as thin piezoelectric paper speaker.

  11. Cellulose Electro-Active Paper: From Discovery to Technology Applications

    Directory of Open Access Journals (Sweden)

    Zafar eAbas

    2014-09-01

    Full Text Available Cellulose electro-active paper (EAPap is an attractive material of electro-active polymers (EAPs family due to its smart characteristics. EAPap is thin cellulose film coated with metal electrodes on both sides. Its large displacement output, low actuation voltage and low power consumption can be used for biomimetic sensors/actuators and electromechanical system. Because cellulose EAPap is ultra-lightweight, easy to manufacture, inexpensive, biocompatible, and biodegradable, it has been employed for many applications such as bending actuator, vibration sensor, artificial muscle, flexible speaker, and can be advantageous in areas such as micro-insect robots, micro-flying objects, microelectromechanical systems, biosensors, and flexible displays.

  12. Antennes lecteurs RFID à polarisation circulaire pour application robotique

    OpenAIRE

    Hebib, Sami; Bouaziz, Sofiene; Aubert, Hervé; Lerasle, Frédéric

    2011-01-01

    National audience Dans ce papier, une nouvelle antenne lecteur RFID à polarisation circulaire a été développée pour la chaine de radiolocalisation du robot Rackham du LAAS-CNRS. Cette antenne (20 cm x 20 cm) permet de couvrir la totalité de bande RFID UHF (860-960 MHz) et présente un gain simulé de 4dBi. Deux exemplaires de cette antenne ont été fabriqués et mesurés. Les tests en radiolocalisation de ces antennes montrent leur conformité aux exigences de l'application robotique considérée....

  13. Conception et calibration d'un sonoreacteur pour l'oxydation de la cellulose par le systeme TEMPO/NaOCl/NaBr

    Science.gov (United States)

    Paquin, Michel

    Avec le contexte economique actuel dans le domaine des pates et papiers au Canada, l'industrie se doit de diversifier ses produits mis en marche. La fermeture de plus de 20 usines depuis 2005, une baisse du PIB de l'industrie de 1,4 milliard CAD entre 1999--2008, une baisse de la demande de 2,4 %, une diminution du prix de la pate de 20,9 % depuis juillet 2009. La delocalisation du secteur vers l'Asie et l'hemisphere sud sont autant de raisons pour laquelle l'industrie se doit d'etre a l'avant plan de nouvelle technologie a base de fibre de bois. Pour augmenter leur rentabilite, l'industrie se doit de diversifier ses produits dans d'autres secteurs que le simple fabricant de papier impression-ecriture. Sa diversification passe par l'elaboration de nouveaux papiers a valeur ajoutee (papier conducteur, papier bioactif, etc.), par l'utilisation de la biomasse forestiere pour la production d'energie, par l'utilisation de la biomasse forestiere pour l'elaboration d'une plateforme de chimie verte, par l'utilisation de la lignine pour le developpement de polymeres et par l'utilisation de la fibre cellulosique pour la fabrication de nanomateriaux. La fabrication de nanofibrille de cellulose peut devenir un des produits qui servira a diversifier la production des usines de pates et papiers. Les nanofibrilles de cellulose possedent des proprietes mecaniques et chimiques exceptionnelles. Les nanofibrilles de cellulose sont fabriquees a partir d'une oxydation selective de la pate kraft de feuillu avec le systeme TEMPO-NaOCl-NaBr. L'oxydation selective de l'alcool primaire en C6 du monomere de glucose sous forme de carboxylates engendre une modification chimique de la cellulose qui accroit l'hydrophilicite des fibrilles. Suite a cette oxydation, nous devons effectuer une desintegration mecanique de la fibre kraft de feuillu oxydee pour separer les fibrilles. Le processus d'oxydation de la fibre par le systeme TEMPO-NaOCl-NaBr et sa defibrillation par la suite engendre une

  14. New application of crystalline cellulose in rubber composites

    Science.gov (United States)

    Bai, Wen

    Rubber without reinforcement has limited applications. The strength of reinforced rubber composites can be ten times stronger than that of unreinforced rubbers. Therefore, rubber composites are widely used in various applications ranging from automobile tires to seals, valves, and gaskets because of their excellent mechanical elastic properties. Silica and carbon black are the two most commonly used reinforcing materials in rubber tires. They are derived from non-renewable materials and are expensive. Silica also contributes to a large amount of ash when used tires are disposed of by incineration. There is a need for a new reinforcing filler that is inexpensive, renewable and easily disposable. Cellulose is the most abundant natural polymer. Native cellulose includes crystalline regions and amorphous regions. Crystalline cellulose can be obtained by removing the amorphous regions with the acid hydrolysis of cellulose because the amorphous cellulose can be hydrolyzed faster than crystalline cellulose. We recently discovered that the partial replacement of silica with microcrystalline cellulose (MCC) provided numerous benefits: (1) low energy consumption for compounding, (2) good processability, (3) strong tensile properties, (4) good heat resistance, and (5) potential for good fuel efficiency in the application of rubber tires. Strong bonding between fillers and a rubber matrix is essential for imparting rubber composites with the desired properties for many specific applications. The bonding between hydrophilic MCC and the hydrophobic rubber matrix is weak and can be improved by addition of a coupling agent or surface modifications of MCC. In this study, MCC was surface-modified with acryloyl chloride or alkenyl ketene dimer (AnKD) to form acrylated MCC (A-MCC) and AnKD-modified MCC (AnKD-MCC). The surface modifications of MCC did not change the integrity and mechanical properties of MCC, but provided functional groups that were able to form covalent linkages with

  15. Conception d'antennes spirales large bande à alimentation coplanaire pour des applications radar sur dirigeable

    OpenAIRE

    Louertani, Karim

    2010-01-01

    Un dirigeable haute altitude (HAA: High Altitude Airship) évoluant à plus de 20 km au-dessus du sol est envisagé en tant que plate-forme d'accueil pour un réseau d'antennes spirales pour des applications radar. L'antenne spirale d'Archimède est un excellent élément rayonnant pour des applications nécessitant une large bande de fréquences ainsi qu'une polarisation circulaire. Dans la plupart des cas, l'alimentation se fait au centre de l'antenne spirale. Cependant, certains environnements inte...

  16. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications.

    Science.gov (United States)

    H P S, Abdul Khalil; Saurabh, Chaturbhuj K; A S, Adnan; Nurul Fazita, M R; Syakir, M I; Davoudpour, Y; Rafatullah, M; Abdullah, C K; M Haafiz, M K; Dungani, R

    2016-10-01

    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications. PMID:27312632

  17. Microfibrillated cellulose - its barrier properties and applications in cellulosic materials: a review.

    Science.gov (United States)

    Lavoine, Nathalie; Desloges, Isabelle; Dufresne, Alain; Bras, Julien

    2012-10-01

    Interest in microfibrillated cellulose (MFC) has been increasing exponentially. During the last decade, this bio-based nanomaterial was essentially used in nanocomposites for its reinforcement property. Its nano-scale dimensions and its ability to form a strong entangled nanoporous network, however, have encouraged the emergence of new high-value applications. In previous years, its mode of production has completely changed, as many forms of optimization have been developed. New sources, new mechanical processes, and new pre- and post-treatments are currently under development to reduce the high energy consumption and produce new types of MFC materials on an industrial scale. The nanoscale characterization possibilities of different MFC materials are thus increasing intensively. Therefore, it is critical to review such MFC materials and their properties. Moreover, very recent studies have proved the significant barrier properties of MFC. Hence, it is proposed to focus on the barrier properties of MFC used in films, in nanocomposites, or in paper coating. PMID:22839998

  18. Recent Progress on Cellulose-Based Electro-Active Paper, Its Hybrid Nanocomposites and Applications.

    Science.gov (United States)

    Khan, Asif; Abas, Zafar; Kim, Heung Soo; Kim, Jaehwan

    2016-01-01

    We report on the recent progress and development of research into cellulose-based electro-active paper for bending actuators, bioelectronics devices, and electromechanical transducers. The cellulose electro-active paper is characterized in terms of its biodegradability, chirality, ample chemically modifying capacity, light weight, actuation capability, and ability to form hybrid nanocomposites. The mechanical, electrical, and chemical characterizations of the cellulose-based electro-active paper and its hybrid composites such as blends or coatings with synthetic polymers, biopolymers, carbon nanotubes, chitosan, and metal oxides, are explained. In addition, the integration of cellulose electro-active paper is highlighted to form various functional devices including but not limited to bending actuators, flexible speaker, strain sensors, energy harvesting transducers, biosensors, chemical sensors and transistors for electronic applications. The frontiers in cellulose paper devices are reviewed together with the strategies and perspectives of cellulose electro-active paper and cellulose nanocomposite research and applications. PMID:27472335

  19. Recent Progress on Cellulose-Based Electro-Active Paper, Its Hybrid Nanocomposites and Applications

    Directory of Open Access Journals (Sweden)

    Asif Khan

    2016-07-01

    Full Text Available We report on the recent progress and development of research into cellulose-based electro-active paper for bending actuators, bioelectronics devices, and electromechanical transducers. The cellulose electro-active paper is characterized in terms of its biodegradability, chirality, ample chemically modifying capacity, light weight, actuation capability, and ability to form hybrid nanocomposites. The mechanical, electrical, and chemical characterizations of the cellulose-based electro-active paper and its hybrid composites such as blends or coatings with synthetic polymers, biopolymers, carbon nanotubes, chitosan, and metal oxides, are explained. In addition, the integration of cellulose electro-active paper is highlighted to form various functional devices including but not limited to bending actuators, flexible speaker, strain sensors, energy harvesting transducers, biosensors, chemical sensors and transistors for electronic applications. The frontiers in cellulose paper devices are reviewed together with the strategies and perspectives of cellulose electro-active paper and cellulose nanocomposite research and applications.

  20. Development of carboxymethyl cellulose acrylate for various biomedical applications

    Science.gov (United States)

    Pal, Kunal; Banthia, A. K.; Majumdar, D. K.

    2006-06-01

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

  1. Development of carboxymethyl cellulose acrylate for various biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Kunal [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Banthia, A K [Materials Science Centre, Indian Institute of Technology, Kharagpur 721302 (India); Majumdar, D K [Delhi Institute of Pharmaceutical Sciences and Research, Formerly College of Pharmacy, University of Delhi, Pushp Vihar, Sector III, New Delhi 110017 (India)

    2006-06-15

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

  2. Development of carboxymethyl cellulose acrylate for various biomedical applications

    International Nuclear Information System (INIS)

    The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogel's permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material

  3. Robotique agricole : quelles applications pour quelles finalités

    OpenAIRE

    Lenain, R.

    2009-01-01

    / Les préoccupations sociétales en terme d'environnement conjuguées aux besoins en nourriture de la population mondiale nécessite l'utilisation de nouvelles technologies pour l'agriculture. Celle-ci doit permettre d'augmenter les niveaux de production tout en réduisant les dommages sur le sol. La robotique apparaît ici comme une solution prometteuse à ces nouveaux enjeux.

  4. SPECIFIC INTERACTION ACTING AT A CELLULOSE-BINDING DOMAIN/CELLULOSE INTERFACE FOR PAPERMAKING APPLICATION

    Directory of Open Access Journals (Sweden)

    Shingo Yokota

    2008-11-01

    Full Text Available Specific and strong cellulose-binding characteristics were utilized for promoting retention of additives in contaminated papermaking systems. Cellulose-binding domain (CBD of cellulase derived from Trichoderma viride was separated by digestion with papain, and then introduced into anionic polyacrylamide (A-PAM through a condensation reaction using water-soluble carbodiimide. The CBD-modified A-PAM (CBD-A-PAM showed good retention on pulp fibers, resulting in high tensile strength paper sheets. The effect remained almost unchanged in the presence of model interfering substances such as ligninsulfonate and Ca2+ ions, whereas commercial cationic paper-strengthening polymer became ineffective. The cellulose-binding force of CBD was quantitatively determined by atomic force microscopy (AFM in the liquid state. Histidine-tagged CBD protein was obtained using Escherichia coli via an expression of CBD derived from Cellulomonas fimi, and immobilized on a gold-coated AFM probe. A strong attractive force was detected only at a CBD/cellulose interface, even when Ca2+ ions were present in high concentration. Direct estimation of CBD affinity for cellulose substrate by AFM would provide significant information on the interfacial interactions useful for the functional design of papermaking additives.

  5. Characterization and Possible Applications of Some Novel Cellulose Derivatives and Composites

    Institute of Scientific and Technical Information of China (English)

    P. Zugenmaier

    2005-01-01

    @@ 1Introduction Cellulose is a naturally occurring linear chain of 1-4 linked β-D-glucopyranose and exhibits great chemical variability and potentials in applications. The cell walls of all plants contain fibers of cellulose. It has long been harvested as commercial fibers from cotton, flax, hemp, sisal, jute and ramie or as wood, which is a common building material or used as a source for purified cellulose. Wood represents a composite material with cellulose as major part combined in excellent form with lignin and hemicelluloses creating a unique high strength and durable material and recently came again into focus as renewable energy resource.

  6. Pour on application of growth promoters in veal calves: analytical and histological results

    NARCIS (Netherlands)

    Schilt, R.; Groot, M.J.; Berende, P.L.M.; Rammazza, V.; Ossenkoppele, J.S.; Haasnoot, W.; Bennekom, van E.O.; Brouwer, L.; Hooijerink, H.

    1998-01-01

    To investigate the possibilities for screening and confirmation methods when the 'pour on' method of application is used for administration of growth promoters, an animal experiment was performed using a cocktail of a combination of growth promoters derived from (illegal) practice. Two cocktails wer

  7. Chitosan blended bacterial cellulose as a smart material for biomedical application

    Science.gov (United States)

    Cai, Zhijiang; Jin, Hyoung-Joon; Kim, Jaehwan

    2009-03-01

    Bacterial cellulose and chitosan blends have been successfully prepared by immersing wet bacterial cellulose pellicle in chitosan solution followed by freeze-drying. By changing chitosan concentration and immersion time, the chitosan content in the blends is ranged from 12% to 45%. The products look like a foam structure. SEM images show that chitosan molecules can penetrate into bacterial cellulose forming multilayer structure. The foam has very well interconnected porous network structure and large aspect surface. By incorporation of chitosan in bacterial cellulose, XRD patterns indicate that crystalline structure does not change but crystallinity decreases from 82% to 61% with chitosan content increasing from 12% to 45%. According to TGA results, the thermal stability has been improved. At the same time, the mechanical properties of bacterial cellulose and chitosan blends are good enough for potential biomedical application such as tissue engineering scaffold and would dressing material.

  8. Application of ethyl cellulose, microcrystalline cellulose and octadecanol for wax based floating solid dispersion pellets.

    Science.gov (United States)

    Yan, Hong-Xiang; Zhang, Shuang-Shuang; He, Jian-Hua; Liu, Jian-Ping

    2016-09-01

    The present study aimed to develop and optimize the wax based floating sustained-release dispersion pellets for a weakly acidic hydrophilic drug protocatechuic acid to achieve prolonged gastric residence time and improved bioavailability. This low-density drug delivery system consisted of octadecanol/microcrystalline cellulose mixture matrix pellet cores prepared by extrusion-spheronization technique, coated with drug/ethyl cellulose 100cp solid dispersion using single-step fluid-bed coating method. The formulation-optimized pellets could maintain excellent floating state without lag time and sustain the drug release efficiently for 12h based on non-Fickian transport mechanism. Observed by SEM, the optimized pellet was the dispersion-layered spherical structure containing a compact inner core. DSC, XRD and FTIR analysis revealed drug was uniformly dispersed in the amorphous molecule form and had no significant physicochemical interactions with the polymer dispersion carrier. The stability study of the resultant pellets further proved the rationality and integrity of the developed formulation. PMID:27185125

  9. Conducting Cellulose Fiber Networks as Flexible Substrate for Optoelectronic Applications

    International Nuclear Information System (INIS)

    Full text: Electronics based on natural materials is becoming increasingly attractive. Paper, a composite of pressed cellulose fibers, has been considered for flexible substrate in thin film electronics, but smoothed with fillers to prevent short circuits. The present study instead uses filler-free cellulose networks by surrounding individual fibers with the entire diode layer stack. Shorts are hindered and the photosensitive area multiplied. The first electrode is hereby established by interconnected silver nanowires adsorbed to the fiber surfaces. The network is subsequently wetted by semiconductor solute, followed by a second electrode. IV characteristics of the conductive paper and diodes based upon will be shown, along with associated micromorphology and optical properties. (author)

  10. Development of Cellulose-Based, Nanostructured, Conductive Paper for Biomolecular Extraction and Energy Storage Applications

    OpenAIRE

    Razaq, Aamir

    2011-01-01

    Conductive paper materials consisting of conductive polymers and cellulose are promising for high-tech applications (energy storage and biosciences) due to outstanding aspects of environmental friendliness, mechanical flexibility, electrical conductivity and efficient electroactive behavior. Recently, a conductive composite paper material was developed by covering the individual nanofibers of cellulose from the green algae Cladophora with a polypyrrole (PPy) layer. The PPy-Cladophora cellulos...

  11. A Strategy to Develop Bioactive Nanoarchitecture Cellulose: Sustained Release and Multifarious Applications.

    Science.gov (United States)

    Karuppusamy, Sembanadar; Pratheepkumar, Annamalai; Dhandapani, Perumal; Maruthamuthu, Sundaram; Kulandainathan, Manickam Anbu

    2015-09-01

    Cellulose membranes were engineered to produce hydrophobic surfaces via a simple and soft chemical process to introduce multifunctional properties of an otherwise hydrophilic cellulose surface with polymer-grafted nanosilver to form a core-shell nanostructure. A superhydrophobic domain of the polymer on cellulose was created through the amide bond formation between the anhydride units of the polymer and the aminosiloxane-functionalized cellulose through layer-over-layer formulation. This formulation was confirmed through XPS, XRD, 29Si-NMR, and FTIR studies. Further, SEM and TEM analysis revealed that short linear silver nanowires were uniformly obtained with an average diameter of 60 nm and length of 288 nm, using a mild reducing agent at 60 degrees C, which resulted in a hierarchical cellulose surface. The nanosilver colloids released from the hierarchical cellulose surface were stabilized by the polymer matrix in solution, which led to a decrease in the rate of formation of Ag+ enhancing the material's killing efficacy against microbes. This biodegradable nanocomposite-based cellulose hierarchical surface development has potential for application as superhydrophobic membranes for oil-water separation, antimicrobial activity, and pH-triggered sustained release of colloidal silver for wound healing, which could possibly be applied for use as smart bandages. PMID:26485925

  12. Application of a water jet system to the pretreatment of cellulose.

    Science.gov (United States)

    Watanabe, Yuka; Kitamura, Shinichi; Kawasaki, Kazunori; Kato, Tomoki; Uegaki, Koichi; Ogura, Kota; Ishikawa, Kazuhiko

    2011-12-01

    Plant cellulose is the most abundant organic compound on earth. Technologies for producing cellulose fiber or improving the enzymatic saccharification of cellulose hold the key to biomass applications. A technology for atomizing biomass without strong acid catalysis remains to be developed. The water jet is a well-known device used in machines (e.g., washing machines, cutters, and mills) that use high-pressure water. In this study, we examined whether a water jet system could be used to atomize crystalline cellulose, which comprises approximately 50% of plant biomass. The Star Burst System manufactured by Sugino Machine Limited (Sugino Machine; Toyama, Japan) is a unique atomization machine that uses a water jet to atomize materials and thereby places lower stress on the environment. After treatment with this system, the crystalline cellulose was converted into a gel-like form. High-angular annular dark-field scanning transmission electron microscopy showed that the cellulose fibers had been converted from a solid crystalline into a matrix of cellulose nanofibers. In addition, our results show that this system can improve the saccharification efficiency of cellulases by more than three-fold. Hence, the Star Burst System provides a new and mild pretreatment system for processing biomass materials. PMID:21698594

  13. Synthesis of cellulose nanofiber composites for mechanical reinforcement and other advanced applications

    Science.gov (United States)

    Xu, Xuezhu

    Cellulose nanofibers from bioresources have attracted intensive research interest in recent years due to their unique combination of properties including high strength and modulus, low density, biocompatibility/biodegradability and rich surface chemistry for functionalization. The nanofibers have been widely studied as nanoreinforcements in polymer nanocomposites; while the nanocomposite research is still very active, new research directions of using the nanofibers for hydrogels/aerogels, template for nanoparticle synthesis, scaffold, carbon materials, nanopaper, etc. have emerged. In this Ph.D. thesis, fundamental studies and application developments are performed on three types of cellulose nanofibers, i.e. cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs) and bacterial cellulose (BC). First CNCs and CNFs are systematically compared in terms of their effects on the mechanical properties, crystallization and failure behavior of the nanocomposites, which provides a guideline for the design of cellulose nanofiber reinforced composites. Second, CNFs and BC are used to develop core-shell carbon fibers and flexible carbon aerogels for energy storage applications. This part is focused on developing nanocarbon materials with multi-scale features. Lastly, hybrid CNC/CNF nanopaper with superior optical, mechanical, and electrical properties is developed and its application is demonstrated on a LED device.

  14. Potential applications of cellulose and chitosan nanoparticles/composites in wastewater treatment: A review.

    Science.gov (United States)

    Olivera, Sharon; Muralidhara, Handanahally Basavarajaiah; Venkatesh, Krishna; Guna, Vijay Kumar; Gopalakrishna, Keshavanarayana; Kumar K, Yogesh

    2016-11-20

    This work concerns the investigation of potential candidature of cellulose and chitosan-based nano-sized materials for heavy metals and dyes removal. Cellulose and chitosan being the first two abundant biopolymers in nature offer wide opportunities to be utilized for high-end applications such as water purification. The nano-sized cellulose and nano-sized chitosan present superior adsorption behavior compared to their micro-sized counterparts. This area of research which explores the possible usage of nano-biopolymers is relatively new. The present review article outlines the development history of research in the field of cellulose and chitosan, various methods employed for the functionalization of the biopolymers, current stage of research, and mechanisms involved in adsorption of heavy metals and dyes using nanocellulose and nanochitosan. The significance of research using nano-biopolymers and future prospects are also identified. PMID:27561533

  15. Composite Risers for Deepwater Applications Risers composites pour applications en mer profonde

    Directory of Open Access Journals (Sweden)

    Metivaud G.

    2006-11-01

    Full Text Available This paper is devoted to the high performance composite tubes developed by the Institut Français du Pétrole (IFP and Aerospatiale for deepwater risers applications. The design principles of the tubes are first presented, along with results of preliminary work carried out as part of the initial feasibility study. Applications of composite tubes to drilling riser Kill and Choke lines and to TLP production risers, both of which have been studied in detail, are then described. Technical and operational advantages obtained from such applications are discussed. Cet article présente les travaux réalisés par l'Institut Français du Pétrole et l'Aerospatiale dans le domaine des tubes composites haute performance pour les applications aux liaisons fond-surface de forage et de production en mer profonde. Les matériaux composites avancés sont une classe de matériaux très particulière, présentant à la fois des caractéristiques mécaniques élevées et une densité spécifique faible. Ils sont utilisés principalement par les industries de l'aéronautique et de l'espace, mais l'industrie pétrolière en mer profonde est un secteur où ils peuvent trouver dans l'avenir des applications très intéressantes, notamment les tubes de risers. Les tubes de risers pétroliers en mer présentent en effet une gamme de spécifications élevées (diamètres, pression, traction, fatigue dans un environnement sévère et leur poids suspendu peut pénaliser fortement les systèmes de forage ou de production par grande profondeur d'eau. Un premier concept de tube composite haute performance a été développé par IFP et Aerospatiale au début des années 1980 ; sa partie courante, réalisée par enroulement filamentaire de fibres de verre R ou de fibres de carbone, et son système d'embout ont été soumis à une série d'essais mécaniques (pression interne jusqu'à 105 MPa, traction supérieure à 1 000 kN pour un diamètre nominal de 0,1 m, millions de

  16. Application of Bacterial Cellulose (BC) in Natural Facial Scrub

    OpenAIRE

    Norhasliza Hasan; Dayang Radiah Awang Biak; Suryani Kamarudin

    2012-01-01

    A new facial scrub containing only natural ingredients and powdered bacterial cellulose (BC) was formulated. The other ingredients used in the formulation include powdered glutinous rice, aloe vera extract, ascorbic acid (Vitamin C) powder and olive oil. The rheological behaviours of the formulated and commercial facial scrubs were tested using plate and plate rheometer. Both formulated and commercial facial scrubs shows shear thinning  behaviour (non-Newtonian liquid). The formulated facial ...

  17. Ring-opening polymerization from cellulose for biocomposite applications

    OpenAIRE

    Lönnberg, Hanna

    2009-01-01

    There is an emerging interest in the development of sustainable materials with high performance. Cellulose is promising in this regard as it is a renewablere source with high specific properties, which can be utilized as strong reinforcements in novel biocomposites. However, to fully exploit the potential ofcellulose, its inherent hydrophilic character has to be modified in order toimprove the compatibility and interfacial adhesion with the more hydrophobicpolymer matrices commonly used in co...

  18. NooJ, un outil TAL pour l'enseignement des langues. Application pour l'étude de la morphologie lexicale en FLE

    Directory of Open Access Journals (Sweden)

    Max Silberztein

    2005-12-01

    Full Text Available NooJ est un système de traitement de corpus – reprenant et améliorant les fonctionnalités d'INTEX – conçu pour l'enseignement des langues et de la linguistique. NooJ intègre des outils de traitement automatique du langage qui offrent à l'enseignant des possibilités de traiter un corpus, et des procédures de recherche, de test, et d'entraînement pour l'étudiant. Nous présentons ici un exemple d'application de NooJ à l'enseignement du français langue étrangère, qui reprend quelques activités sur l'étude de la morphologie lexicale.

  19. Cellulosic materials as biopolymers and supercritical CO2as a green process: chemistry and applications

    OpenAIRE

    Medina-González, Yaocihuatl; Camy, Séverine; Condoret, Jean-Stéphane

    2012-01-01

    In this review, we describe the use of supercritical CO2 (scCO2) in several cellulose applications. The focus is on different technologies that either exist or are expected to emerge in the near future. The applications are wide from the extraction of hazardous wastes to the cleaning and reuse of paper or production of glucose. To put this topic in context, cellulose chemistry and its interactions with scCO2 are described. The aim of this study was to discuss the new emerging technologies and...

  20. Graphene oxide/cellulose aerogels nanocomposite: Preparation, pyrolysis, and application for electromagnetic interference shielding.

    Science.gov (United States)

    Wan, Caichao; Li, Jian

    2016-10-01

    Hybrid aerogels consisting of graphene oxide (GO) and cellulose were prepared via a solution mixing-regeneration-freeze drying process. The presence of GO affected the micromorphology of the hybrid aerogels, and a self-assembly behavior of cellulose was observed after the incorporation of GO. Moreover, there is no remarkable modification in the crystallinity index and thermal stability after the insertion of GO. After the reduction of GO in the hybrid aerogels by l-ascorbic acid and the subsequent pyrolysis of the aerogels, the resultant displays some interesting characteristics, including good electromagnetic interference (EMI) shielding capacity (SEtotal=58.4dB), high electrical conductivity (19.1Sm(-1)), hydrophobicity, and fire resistance, which provide an opportunity for some advanced applications such as EMI protection, electrochemical devices, water-proofing agents, and fire retardants. Moreover, this work possibly helps to facilitate the development of both cellulose and GO-based materials and expand their application scope. PMID:27312627

  1. Present status and applications of bacterial cellulose-based materials for skin tissue repair.

    Science.gov (United States)

    Fu, Lina; Zhang, Jin; Yang, Guang

    2013-02-15

    Bacterial cellulose (BC, also known as microbial cellulose, MC) is a promising natural polymer which is biosynthesized by certain bacteria. This review focused on BC-based materials which can be utilized for skin tissue repair. Firstly, it is illustrated that BC has unique structural and mechanical properties as compared with higher plant cellulose, and is thus expected to become a commodity material. Secondly, we summarized the basic properties and different types of BC, including self-assembled, oriented BC, and multiform BC. Thirdly, composites prepared by using BC in conjunction with other polymers are explored, and the research on BC for application in skin tissue engineering is addressed. Finally, experimental results and clinical treatments assessing the performance of wound healing materials based on BC were examined. With its superior mechanical properties, as well as its excellent biocompatibility, BC was shown to have great potential for biomedical application and very high clinical value for skin tissue repair. PMID:23399174

  2. Feasibility Investigation of Cellulose Polymers for Mucoadhesive Nasal Drug Delivery Applications.

    Science.gov (United States)

    Hansen, Kellisa; Kim, Gwangseong; Desai, Kashappa-Goud H; Patel, Hiren; Olsen, Karl F; Curtis-Fisk, Jaime; Tocce, Elizabeth; Jordan, Susan; Schwendeman, Steven P

    2015-08-01

    The feasibility of various cellulose polymer derivatives, including methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), sodium-carboxymethylcellulose (sodium-CMC), and cationic-hydroxyethylcellulose (cationic-HEC), for use as an excipient to enhance drug delivery in nasal spray formulations was investigated. Three main parameters for evaluating the polymers in nasal drug delivery applications include rheology, ciliary beat frequency (CBF), and permeation across nasal tissue. Reversible thermally induced viscosity enhancement was observed at near nasal physiological temperature when cellulose derivatives were combined with an additional excipient, poly(vinyl caprolactam)-poly(vinyl acetate)-poly(ethylene glycol) graft copolymer (PVCL-PVA-PEG). Cationic-HEC was shown to enhance acyclovir permeation across the nasal mucosa. None of the tested cellulosic polymers caused any adverse effects on porcine nasal tissues and cells, as assessed by alterations in CBF. Upon an increase in polymer concentration, a reduction in CBF was observed when ciliated cells were immersed in the polymer solution, and this decrease returned to baseline when the polymer was removed. While each cellulose derivative exhibited unique advantages for nasal drug delivery applications, none stood out on their own to improve more than one of the performance characteristics examined. Hence, these data may be useful for the development of new cellulose derivatives in nasal drug formulations. PMID:26097994

  3. Noble metal/functionalized cellulose nanofiber composites for catalytic applications.

    Science.gov (United States)

    Gopiraman, Mayakrishnan; Bang, Hyunsik; Yuan, Guohao; Yin, Chuan; Song, Kyung-Hun; Lee, Jung Soon; Chung, Ill Min; Karvembu, Ramasamy; Kim, Ick Soo

    2015-11-01

    In this study, cellulose acetate nanofibers (CANFs) with a mean diameter of 325 ± 2.0 nm were electrospun followed by deacetylation and functionalization to produce anionic cellulose nanofibers (f-CNFs). The noble metal nanoparticles (RuNPs and AgNPs) were successfully decorated on the f-CNFs by a simple wet reduction method using NaBH4 as a reducing agent. TEM and SEM images of the nanocomposites (RuNPs/CNFs and AgNPs/CNFs) confirmed that the very fine RuNPs or AgNPs were homogeneously dispersed on the surface of f-CNFs. The weight percentage of the Ru and Ag in the nanocomposites was found to be 13.29 wt% and 22.60 wt% respectively; as confirmed by SEM-EDS analysis. The metallic state of the Ru and Ag in the nanocomposites was confirmed by XPS and XRD analyses. The usefulness of these nanocomposites was realized from their superior catalytic activity. In the aerobic oxidation of benzyl alcohol to benzaldehyde, the RuNPs/CNFs system gave a better yield of 89% with 100% selectivity. Similarly, the AgNPs/CNFs produced an excellent yield of 99% (100% selectivity) in the aza-Michael reaction of 1-phenylpiperazine with acrylonitrile. Mechanism has been proposed for the catalytic systems. PMID:26256382

  4. Methylcellulose, a Cellulose Derivative with Original Physical Properties and Extended Applications

    OpenAIRE

    Pauline L. Nasatto; Frédéric Pignon; Silveira, Joana L.M.; Maria Eugênia R. Duarte; Miguel D. Noseda; Marguerite Rinaudo

    2015-01-01

    This review covers the preparation, characterization, properties, and applications of methylcelluloses (MC). In particular, the influence of different chemical modifications of cellulose (under both heterogeneous and homogeneous conditions) is discussed in relation to the physical properties (solubility, gelation) of the methylcelluloses. The molecular weight (MW) obtained from the viscosity is presented together with the nuclear magnetic resonance (NMR) analysis required for the determinatio...

  5. Micro-Nanostructured Polyaniline Assembled in Cellulose Matrix via Interfacial Polymerization for Applications in Nerve Regeneration.

    Science.gov (United States)

    Xu, Dingfeng; Fan, Lin; Gao, Lingfeng; Xiong, Yan; Wang, Yanfeng; Ye, Qifa; Yu, Aixi; Dai, Honglian; Yin, Yixia; Cai, Jie; Zhang, Lina

    2016-07-13

    Conducting polymers have emerged as frontrunners to be alternatives for nerve regeneration, showing a possibility of the application of polyaniline (PANI) as the nerve guidance conduit. In the present work, the cellulose hydrogel was used as template to in situ synthesize PANI via the limited interfacial polymerization method, leading to one conductive side in the polymer. PANI sub-micrometer dendritic particles with mean diameter of ∼300 nm consisting of the PANI nanofibers and nanoparticles were uniformly assembled into the cellulose matrix. The hydrophobic PANI nanoparticles were immobilized in the hydrophilic cellulose via the phytic acid as "bridge" at presence of water through hydrogen bonding interaction. The PANI/cellulose composite hydrogels exhibited good mechanical properties and biocompatibility as well as excellent guiding capacity for the sciatic nerve regeneration of adult Sprague-Dawley rats without any extra treatment. On the basis of the fact that the pure cellulose hydrogel was an inert material for the neural repair, PANI played an indispensable role on the peripheral nerve regeneration. The hierarchical micro-nanostructure and electrical conductivity of PANI could remarkably induce the adhesion and guiding extension of neurons, showing its great potential in biomedical materials. PMID:27314673

  6. Progress in bacterial cellulose matrices for biotechnological applications.

    Science.gov (United States)

    Cacicedo, Maximiliano L; Castro, M Cristina; Servetas, Ioannis; Bosnea, Loulouda; Boura, Konstantina; Tsafrakidou, Panagiota; Dima, Agapi; Terpou, Antonia; Koutinas, Athanasios; Castro, Guillermo R

    2016-08-01

    Bacterial cellulose (BC) is an extracellular polymer produced by many microorganisms. The Komagataeibacter genus is the best producer using semi-synthetic media and agricultural wastes. The main advantages of BC are the nanoporous structure, high water content and free hydroxyl groups. Modification of BC can be made by two strategies: in-situ, during the BC production, and ex-situ after BC purification. In bioprocesses, multilayer BC nanocomposites can contain biocatalysts designed to be suitable for outside to inside cell activities. These nanocomposites biocatalysts can (i) increase productivity in bioreactors and bioprocessing, (ii) provide cell activities does not possess without DNA cloning and (iii) provide novel nano-carriers for cell inside activity and bioprocessing. In nanomedicine, BC matrices containing therapeutic molecules can be used for pathologies like skin burns, and implantable therapeutic devices. In nanoelectronics, semiconductors BC-based using salts and synthetic polymers brings novel films showing excellent optical and photochemical properties. PMID:26927233

  7. Application of cellulose acetate for controlled release of thymol.

    Science.gov (United States)

    Milovanovic, Stoja; Markovic, Darka; Aksentijevic, Ksenija; Stojanovic, Dusica B; Ivanovic, Jasna; Zizovic, Irena

    2016-08-20

    Cellulose acetate (CA) was investigated as a carrier towards development of material with controlled release of thymol as a natural substance with strong antibacterial properties using high pressure techniques. Effect of thymol content on CA was confirmed by SEM, FTIR and DSC methods. Kinetic of thymol release from CA was tested using simulated gastric and intestinal fluids (hydrochloric acid and phosphate buffer saline). Results were correlated with Korsmeyer-Peppas and Weibull model. Depending on the thymol content and chemical nature of the release medium, the time of thymol release varied from one to three days indicating CA as a promising carrier of thymol with potential uses from medicine to agriculture. The impregnated CA showed antibacterial activity against 23 tested bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) which is particularly important bearing in mind that this strain causes fatal infections in humans and animals. PMID:27178940

  8. Cellulose based conductive polymers

    OpenAIRE

    Lin, Haishu

    2015-01-01

    Conductive fibers show potential applications in different areas. In this thesis, cellulose and its derivatives, including carboxymethyl cellulose, cellulose acetate as well as methyl cellulose were used to produce fibers via wet spinning. Different conductive materials were also introduced in an attempt to obtain cellulose-derived conductive fibers. Different conductive fillers (Zelec, carbon black, conductive polymers) were evaluated. Among them, PEDOT and PPy conductive polymers showed...

  9. Nanoparticules d'orthovanadate d'yttrium : fonctionnalisation et application comme sondes luminescentes pour la biologie.

    OpenAIRE

    Giaume, Domitille

    2006-01-01

    Ce travail de thèse a été réalisé au laboratoire de Physique de la Matière Condensée, au sein du groupe de Chimie du Solide. L'une des thématiques de cette équipe concerne l'élaboration de nanomatériaux luminescents, utilisés dans de nombreuses applications comme les systèmes d'éclairage ou de visualisation transparents. L'une des récentes applications de certains nanomatériaux luminescents a été dans le domaine de la biologie, tant pour le développement de biopuces, d'agents de contraste, de...

  10. Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Gao; Dai-di Fan; Pei Ma; Yan-e Luo; Xiao-xuan Ma; Chen-hui Zhu; Jun-feng Hui

    2009-01-01

    Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulosc Congo red coltnre medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.

  11. Atmospheric plasma assisted PLA/microfibrillated cellulose (MFC) multilayer biocomposite for sustainable barrier application

    DEFF Research Database (Denmark)

    Meriçer, Çağlar; Minelli, Matteo; Angelis, Maria G De;

    2016-01-01

    Fully bio-based and biodegradable materials, such as polylactic acid (PLA) and microfibrillated cellulose (MFC), are considered in order to produce a completely renewable packaging solution for oxygen barrier applications, even at medium-high relative humidity (R.H.). Thin layers of MFC were coated...... possible use in barrier packaging applications as fully biodegradable solution, coupling two primarily incompatible matrices in a multilayer film with no need of any solvent or chemical....

  12. Application of Bacterial Cellulose (BC in Natural Facial Scrub

    Directory of Open Access Journals (Sweden)

    Norhasliza Hasan

    2012-01-01

    Full Text Available A new facial scrub containing only natural ingredients and powdered bacterial cellulose (BC was formulated. The other ingredients used in the formulation include powdered glutinous rice, aloe vera extract, ascorbic acid (Vitamin C powder and olive oil. The rheological behaviours of the formulated and commercial facial scrubs were tested using plate and plate rheometer. Both formulated and commercial facial scrubs shows shear thinning  behaviour (non-Newtonian liquid. The formulated facial scrub sample had a higher viscosity at low shear rates compared to the commercial facial scrub (459.7 Pa.s against 359.2 Pa.s at 10s-1, but had a nearly similar viscosity at high shear rates (197.2 Pa.s against 192 Pa.s at 25s-1. By adding preservative, the shelf life of the scrub was two times longer than that without preservatives. The  tested sample dried out after 10 minutes at room temperature (~30°C.

  13. Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplis...

  14. A multipurpose natural and renewable polymer in medical applications: Bacterial cellulose.

    Science.gov (United States)

    de Oliveira Barud, Hélida Gomes; da Silva, Robson Rosa; da Silva Barud, Hernane; Tercjak, Agnieszka; Gutierrez, Junkal; Lustri, Wilton Rogério; de Oliveira, Osmir Batista; Ribeiro, Sidney J L

    2016-11-20

    Bacterial cellulose (BC) produced by some bacteria, among them Gluconacetobacter xylinum, which secrets an abundant 3D networks fibrils, represents an interesting emerging biocompatible nanomaterial. Since its discovery BC has shown tremendous potential in a wide range of biomedical applications, such as artificial skin, artificial blood vessels and microvessels, wound dressing, among others. BC can be easily manipulated to improve its properties and/or functionalities resulting in several BC based nanocomposites. As example BC/collagen, BC/gelatin, BC/Fibroin, BC/Chitosan, etc. Thus, the aim of this review is to discuss about the applicability in biomedicine by demonstrating a variety of forms of this biopolymer highlighting in detail some qualities of bacterial cellulose. Therefore, various biomedical applications ranging from implants and scaffolds, carriers for drug delivery, wound-dressing materials, etc. that were reported until date will be presented. PMID:27561512

  15. More than meets the eye in bacterial cellulose: biosynthesis, bioprocessing, and applications in advanced fiber composites.

    Science.gov (United States)

    Lee, Koon-Yang; Buldum, Gizem; Mantalaris, Athanasios; Bismarck, Alexander

    2014-01-01

    Bacterial cellulose (BC) nanofibers are one of the stiffest organic materials produced by nature. It consists of pure cellulose without the impurities that are commonly found in plant-based cellulose. This review discusses the metabolic pathways of cellulose-producing bacteria and the genetic pathways of Acetobacter xylinum. The fermentative production of BC and the bioprocess parameters for the cultivation of bacteria are also discussed. The influence of the composition of the culture medium, pH, temperature, and oxygen content on the morphology and yield of BC are reviewed. In addition, the progress made to date on the genetic modification of bacteria to increase the yield of BC and the large-scale production of BC using various bioreactors, namely static and agitated cultures, stirred tank, airlift, aerosol, rotary, and membrane reactors, is reviewed. The challenges in commercial scale production of BC are thoroughly discussed and the efficiency of various bioreactors is compared. In terms of the application of BC, particular emphasis is placed on the utilization of BC in advanced fiber composites to manufacture the next generation truly green, sustainable and renewable hierarchical composites. PMID:23897676

  16. Chitosan/titanium dioxide nanocomposite coatings: Rheological behavior and surface application to cellulosic paper.

    Science.gov (United States)

    Tang, Yanjun; Hu, Xiulan; Zhang, Xinqi; Guo, Daliang; Zhang, Junhua; Kong, Fangong

    2016-10-20

    Incorporation of nanofillers into a polymeric matrix has received much attention as a route to reinforced polymer nanocomposites. In the present work, an environmentally friendly chitosan (CTS)/titanium dioxide (TiO2) nanocomposite coating was designed/prepared and subsequently employed for imparting antibacterium and improved mechanical properties to cellulosic paper via surface coating. Effect of TiO2 nanoparticle loadings on the rheological behavior of nanocomposite coatings was investigated. Surface application of CTS/TiO2 nanocomposite coatings to cellulosic paper was performed, and the antibacterial activity and mechanical properties of surface-coated cellulosic paper were examined. Results showed that the increased TiO2 nanoparticle loadings decreased the viscosity and dynamic viscoelasticity of the as-prepared coatings, and improved the antibacterial activity and mechanical properties of surface-coated cellulosic paper. The optimum loading of TiO2 nanoparticles was identified at 10%. This work suggested that CTS/TiO2 nanocomposite coatings may have the potential to be used as a promising antibacterial protective coating for paper packaging. PMID:27474622

  17. Combined Application of Microbial Cellulose and Papaver macrostomum Extract on Bedsore Microorganisms

    Directory of Open Access Journals (Sweden)

    Anita Khanafari,

    2013-05-01

    caused a decrease in the growth of bedsore microorganisms with the minimum extract concentration, 100μl..Conclusions: Combination of bio-cellulose and P. macrostomum flower ethanol extract can be used for patients who suffer from bedsore lesions in concentration 0.1% of MBCs. Furthermore, clinical studies are needed to confirm the efficiency of in vivo application.

  18. Advances in biomedical and pharmaceutical applications of functional bacterial cellulose-based nanocomposites.

    Science.gov (United States)

    Ullah, Hanif; Wahid, Fazli; Santos, Hélder A; Khan, Taous

    2016-10-01

    Bacterial cellulose (BC) synthesized by certain species of bacteria, is a fascinating biopolymer with unique physical and mechanical properties. BC's applications range from traditional dessert, gelling, stabilizing and thickening agent in the food industry to advanced high-tech applications, such as immobilization of enzymes, bacteria and fungi, tissue engineering, heart valve prosthesis, artificial blood vessels, bone, cartilage, cornea and skin, and dental root treatment. Various BC-composites have been designed and investigated in order to enhance its biological applicability. This review focuses on the application of BC-based composites for microbial control, wound dressing, cardiovascular, ophthalmic, skeletal, and endodontics systems. Moreover, applications in controlled drug delivery, biosensors/bioanalysis, immobilization of enzymes and cells, stem cell therapy and skin tissue repair are also highlighted. This review will provide new insights for academia and industry to further assess the BC-based composites in terms of practical applications and future commercialization for biomedical and pharmaceutical purposes. PMID:27312644

  19. Applicability of bacterial cellulose as an alternative to paper points in endodontic treatment.

    Science.gov (United States)

    Yoshino, Aya; Tabuchi, Mari; Uo, Motohiro; Tatsumi, Hiroto; Hideshima, Katsumi; Kondo, Seiji; Sekine, Joji

    2013-04-01

    Dental root canal treatment is required when dental caries progress to infection of the dental pulp. A major goal of this treatment is to provide complete decontamination of the dental root canal system. However, the morphology of dental root canal systems is complex, and many human dental roots have inaccessible areas. In addition, dental reinfection is fairly common. In conventional treatment, a cotton pellet and paper point made from plant cellulose is used to dry and sterilize the dental root canal. Such sterilization requires a treatment material with high absorbency to remove any residue, the ability to improve the efficacy of intracanal medication and high biocompatibility. Bacterial cellulose (BC) is produced by certain strains of bacteria. In this study, we developed BC in a pointed form and evaluated its applicability as a novel material for dental canal treatment with regard to solution absorption, expansion, tensile strength, drug release and biocompatibility. We found that BC has excellent material and biological characteristics compared with conventional materials, such as paper points (plant cellulose). BC showed noticeably higher absorption and expansion than paper points, and maintained a high tensile strength even when wet. The cumulative release of a model drug was significantly greater from BC than from paper points, and BC showed greater compatibility than paper points. Taken together, BC has great potential for use in dental root canal treatment. PMID:23268234

  20. Biomimetic design of a bacterial cellulose/hydroxyapatite nanocomposite for bone healing applications

    International Nuclear Information System (INIS)

    This study describes the design and synthesis of bacterial cellulose/hydroxyapatite nanocomposites for bone healing applications using a biomimetic approach. Bacterial cellulose (BC) with various surface morphologies (pellicles and tubes) was negatively charged by the adsorption of carboxymethyl cellulose (CMC) to initiate nucleation of calcium-deficient hydroxyapatite (cdHAp). The cdHAp was grown in vitro via dynamic simulated body fluid (SBF) treatments over a one week period. Characterization of the mineralized samples was done with X-ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM) with Energy Dispersive Spectroscopy (EDS). The amount of cdHAp observed varied among different samples. XPS demonstrated that the atomic presence of calcium and phosphorus ranged from 0.44 at.% to 7.71 at.% Ca and 0.27 at.% to 11.18 at.% P. The Ca/P overall ratio ranged from 1.22 to 1.92. FESEM images showed that the cdHAp crystal size increased with increasing nanocellulose fibril density. To determine the viability of the scaffolds in vitro, the morphology and differentiation of osteoprogenitor cells was analyzed using fluorescence microscopy and alkaline phosphatase gene expression. The presence of cdHAp crystals on BC surfaces resulted in increased cell attachment.

  1. NanoCrystalline Cellulose, an environmental friendly nanoparticle for pharmaceutical application – A quick study

    Directory of Open Access Journals (Sweden)

    Song Yee Kai

    2016-01-01

    Full Text Available Nanocrystalline cellulose (NCC is probably the most abundant nano material can be found in nature. It offers not only substantial environmental advantage due to its intrinsic biocompatibility and biodegradability, but also outstanding aspect ratio, tension modulus, bioavailability and permeability. NCC can be isolated from low value biomass through a well-developed acid hydrolysis method, and the structure can be readily manipulated during extraction to obtain desirable size distribution, surface charge and degree of crystallinity. Erratic absorption of drug has been a major issue for years until the emergence of nanoparticle adopted as smart vehicle for drug delivery. However, due to inevitably severe toxicity and the side effect from ordinary nanoparticle, the exploration of green nanoparticles are catching escalating attention is now in urge. Microcrystalline cellulose (MCC has long been an option, nevertheless, due to their relatively low surface charge compared to total volume, drug release in a control manner was hardly satisfied. It is suggested that the above limitation can be overcome by nanocrystalline cellulose. This article discusses and explores their potential in cosmetic, personal care and pharmaceutical application, and the recent development in term of preparation and characteristic.

  2. Biomimetic design of a bacterial cellulose/hydroxyapatite nanocomposite for bone healing applications

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, Kristen A., E-mail: kazimmer@vt.edu [Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24060 (United States); School of Biomedical Engineering Sciences, Virginia Tech, Blacksburg, VA 24060 (United States); LeBlanc, Jill M.; Sheets, Kevin T.; Fox, Robert W. [Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24060 (United States); Gatenholm, Paul [Department of Materials Science and Engineering, Virginia Tech, Blacksburg, VA 24060 (United States); School of Biomedical Engineering Sciences, Virginia Tech, Blacksburg, VA 24060 (United States)

    2011-01-01

    This study describes the design and synthesis of bacterial cellulose/hydroxyapatite nanocomposites for bone healing applications using a biomimetic approach. Bacterial cellulose (BC) with various surface morphologies (pellicles and tubes) was negatively charged by the adsorption of carboxymethyl cellulose (CMC) to initiate nucleation of calcium-deficient hydroxyapatite (cdHAp). The cdHAp was grown in vitro via dynamic simulated body fluid (SBF) treatments over a one week period. Characterization of the mineralized samples was done with X-ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FESEM) with Energy Dispersive Spectroscopy (EDS). The amount of cdHAp observed varied among different samples. XPS demonstrated that the atomic presence of calcium and phosphorus ranged from 0.44 at.% to 7.71 at.% Ca and 0.27 at.% to 11.18 at.% P. The Ca/P overall ratio ranged from 1.22 to 1.92. FESEM images showed that the cdHAp crystal size increased with increasing nanocellulose fibril density. To determine the viability of the scaffolds in vitro, the morphology and differentiation of osteoprogenitor cells was analyzed using fluorescence microscopy and alkaline phosphatase gene expression. The presence of cdHAp crystals on BC surfaces resulted in increased cell attachment.

  3. Cotton-based Cellulose Nanomaterials for Applications in Composites and Electronics

    Science.gov (United States)

    Farahbakhsh, Nasim

    A modern society demands development of highly valued and sustainable products via innovative process technologies and utilizing bio-based alternatives for petroleum based materials. Systematic comparative study of nanocellulose particles as a biodegradable and renewable reinforcing agent can help to develop criteria for selecting an appropriate candidate to be incorporated in polymer nanocomposites. Of particular interest has been nanocellulosic materials including cellulose nanocrystal (CNC) and micro/nanofibrilated cellulose (MFC/NFC) which possess a hierarchical structure that permits an ordered structure with unique properties that has served as building blocks for the design of green and novel materials composites for applications in flexible electronics, medicine and composites. Key differences exist in nanocellulosic materials as a result the process by which the material is produced. This research demonstrates the applicability for the use of recycled cotton as promising sustainable material to be utilized as a substrate for electronic application and a reinforcing agent choice that can be produced without any intensive purification process and be applied to synthetic-based polymer nanocomposites in melt-processing. (Abstract shortened by ProQuest.).

  4. Bacterial cellulose-kaolin nanocomposites for application as biomedical wound healing materials

    Science.gov (United States)

    Wanna, Dwi; Alam, Catharina; Toivola, Diana M.; Alam, Parvez

    2013-12-01

    This short communication provides preliminary experimental details on the structure-property relationships of novel biomedical kaolin-bacterial cellulose nanocomposites. Bacterial cellulose is an effective binding agent for kaolin particles forming reticulated structures at kaolin-cellulose interfaces and entanglements when the cellulose fraction is sufficiently high. The mechanical performance of these materials hence improves with an increased fraction of bacterial cellulose, though this also causes the rate of blood clotting to decrease. These composites have combined potential as both short-term (kaolin) and long-term (bacterial cellulose) wound healing materials.

  5. Application of tetra-n-methylammonium hydroxide on cellulose dissolution and isolation from sugarcane bagasse.

    Science.gov (United States)

    Zhong, Chao; Wang, Chunming; Wang, Fengxue; Jia, Honghua; Wei, Ping; Zhao, Yin

    2016-01-20

    Cellulose isolation, a promising way for lignocellulosic biomass utilization, is always restricted by the poor solubility of cellulose. In this paper, tetra-n-methylammonium hydroxide (TMAH) was confirmed to be capable of readily dissolving/regenerating cellulose without chemical modification at room temperature. Meanwhile, cellulose isolation from lignocellulosic biomass by initially dissolving the biomass in TMAH followed by cellulose precipitation was proposed, and the isolated substance with average cellulose purity of 92.1 ± 0.3% could be obtained throughout this process under the optimum conditions: temperature 52 °C, time 60 min, and loading ratio of TMAH/biomass (w/w) 7.2:1. Besides, high efficiency cellulose isolation (i.e. >70% cellulose purity) could be continuously remained during 4-round cycles by using the recycled TMAH solvent without distinct activity loss. PMID:26572437

  6. New cellulose-lignin hydrogels and their application in controlled release of polyphenols

    Energy Technology Data Exchange (ETDEWEB)

    Ciolacu, Diana, E-mail: dciolacu@icmpp.ro; Oprea, Ana Maria; Anghel, Narcis; Cazacu, Georgeta; Cazacu, Maria

    2012-04-01

    Novel superabsorbant cellulose-lignin hydrogels (CL) were prepared by a new two-step procedure consisting in dissolving cellulose in an alkaline solution with further mixing with lignin, followed by the chemical crosslinking with epichlorohydrin. The crosslinking occurrence was verified by Fourier Transform Infrared spectroscopy (FT-IR). The effect of the structure features of cellulose-lignin hydrogels on their dehydration heat was evaluated by Differential Scanning Calorimetry (DSC). The Scanning Electron Microscopy (SEM) images reveal some morphological aspects of the hydrogels. The degree as well as the rate of swelling in a mixture of water:ethanol = 19:1 were estimated. The possible application of these hydrogels as controlled release systems was tested. Polyphenols known as having a wide range of biological effects were selected to be incorporated in such hydrogels by an optimal procedure. The extract of grapes seeds from the Chambourcin type was used as a source of polyphenols (PF). The amount of the incorporated polyphenols was estimated by UV-VIS measurements. Characterization of the hydrogels containing polyphenols was performed by FTIR spectroscopy. Some parameters were estimated based on the registered spectra, as H-bond energy (E{sub H}), the asymmetric index (a/b) and the enthalpy of H-bond formation ({Delta}H). The modifications of the thermal behavior and morphology induced by the presence of the polyphenols in hydrogels were highlighted by DSC and SEM, respectively. The release of polyphenols from CL hydrogels depended on the lignin content from matrices, as assessed by spectral studies. Both loading with polyphenols and their release can be controlled by the composition of the hydrogels. The kinetic of polyphenols release was studied. - Highlights: Black-Right-Pointing-Pointer A unique method to obtain cellulose-lignin hydrogels. Black-Right-Pointing-Pointer The application of these hydrogels as controlled release systems was tested. Black

  7. More Than Meets the Eye in Bacterial Cellulose: Biosynthesis, Bioprocessing, and Applications in Advanced Fiber Composites.

    OpenAIRE

    Lee, K Y; Buldum, G.; Mantalaris, A.; Bismarck, A.

    2014-01-01

    Bacterial cellulose (BC) nanofibers are one of the stiffest organic materials produced by nature. It consists of pure cellulose without the impurities that are commonly found in plant-based cellulose. This review discusses the metabolic pathways of cellulose-producing bacteria and the genetic pathways of Acetobacter xylinum. The fermentative production of BC and the bioprocess parameters for the cultivation of bacteria are also discussed. The influence of the composition of the culture medium...

  8. Surface Modification of Cellulose by Covalent Grafting and Physical Adsorption for Biocomposite Applications

    OpenAIRE

    Bruce, Carl

    2014-01-01

    There is an increasing interest to replace fossil-based materials with renewable alternatives. Cellulose fibers/nanofibrils (CNF) are sustainable options since they are biobased and biodegradable. In addition, they combine low weight with high strength; making them suitable to, for example, reinforce composites. However, to be able to use them as such, modifications are often necessary. This study therefore aimed at modifying cellulose fibers, model surfaces of cellulose and CNF. Cellulose fi...

  9. DIMENSIONNEMENT PAR OPTIMISATION DES INDUCTEURS A AIMANTS POUR APPLICATION AUXILIAIRE AUTOMOBILE

    OpenAIRE

    Mateos Bugatti, Manuela

    2004-01-01

    Au cours de ce travail, nous nous sommes intéressés à la problématique du dimensionnement des inducteurs à aimants ferrites pour moteurs d'auxiliaire automobile, aussi bien brushless qu'à courant continu. Un outil informatique permettant de trouver les grandeurs géométriques et physiques optimales pour un inducteur, tout en respectant le cahier des charges, a été réalisé. Cet outil s'appuie sur un modèle analytique de l'inducteur, basé sur la résolution formelle des équations de champ, qui a ...

  10. Systèmes experts à base de connaissances profondes : application à un poste de travail intelligent pour le comptable

    OpenAIRE

    Page, Michel

    1990-01-01

    La plupart des systèmes experts actuels reposent sur les connaissances de surface (le savoir-faire) d'un expert du domaine d'application. Plus récemment, une autre approche s'est développée. Elle vise a exploiter les connaissances profondes (théoriques) acquises dans le domaine d'application. La thèse étudie cette dernière approche dans le cadre du projet pic (poste de travail intelligent pour le comptable). Les aspects méthodologiques sont développés dans la première partie. Une nouvelle cla...

  11. Synthesis and study of nano-structured cellulose acetate based materials for energy applications

    International Nuclear Information System (INIS)

    Nano-structured materials have unique properties (high exchange areas, containment effect) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO2 supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nano-materials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a poly-functional iso-cyanate. The dry materials obtained after solvent extraction with supercritical CO2 are nano-structured and mainly meso-porous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultra-porous reference aerogel, with a density equals to 0,245 g.cm-3 together with a meso-porous volume of 3,40 cm3.g-1 was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W.m-1.K-1. In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nano-structured and nano-porous, even if important structural modifications have occurred during the carbonization process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels). (author)

  12. Potential of nanocrystalline cellulose-fibrin nanocomposites for artificial vascular graft applications

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Elvie; Hu, Dehong; Abu-Lail, Nehal; Zhang, Xiao

    2013-02-19

    Nanocrystalline cellulose, a new bio-nanomaterial is utilized as a reinforcing material for biocompatible fibrin matrix to form into a nanocomposite for small-diameter replacement vascular graft application (SDRVG). The periodate oxidation of NCC, which provided it with a reactive carbonyl group, allowed molecular interaction between NCC and fibrin. Such interaction resulted into an effective mechanical reinforcement indicated by the improvement of max. force, elongation at break and modulus when oxidized NCC (ONCC) was incorporated into fibrin. The nanocomposite’s mechanical properties can be manipulated to conform to the native blood vessel by varying the ONCC to fibrin ratio and/or by controlling the degree of oxidation of NCC. Using atomic force microscopy had provided fundamental information on the effects of molecular interactions to the nanolevel mechanical properties of NCC/fibrin nanocomposites. This fundamental information established the positive feasibility and commenced continuing investigation for the practical SDRVG application of NCC/fibrin nanocomposite.

  13. Thermo-responsive hydrogels from cellulose-based polyelectrolytes and catanionic vesicles for biomedical application.

    Science.gov (United States)

    Milcovich, Gesmi; Antunes, Filipe; Golob, Samuel; Farra, Rossella; Grassi, Mario; Voinovich, Dario; Grassi, Gabriele; Asaro, Fioretta

    2016-07-01

    In this study, negatively charged catanionic vesicles/hydrophobically modified hydroxyethylcellulose polymers thermo-responsive hydrogels have been fabricated. Vesicular aggregates were found to act as multifunctional junctions for networking of modified-cellulose water solutions. The contributions of the electrostatic and hydrophobic interactions were evaluated by changing either vesicles composition or the polymer hydrophobic substitution. Thermal-induced size and lamellarity of hydrogel-enclosed vesicles were detected, with further polygonal shape changes induced by cellulose-based polymer addition. The thermal transition was also found to tune hydrogel mechanical behaviour. The network formation was further assessed through molecular insights, which allow to determine the arrangement of the polymer chains on the vesicles' surface. The examined systems exhibited interesting thermo-responsive characteristics. Thus, vesicularly cross-linked hydrogels herein presented can offer a wide variety of applications, i.e. in biomedical field, as multi-drug delivery systems, thanks to their ability to provide for different environments to guest molecules, comprising bulk water, vesicles' interior and bilayers, sites on polymeric chains. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1668-1679, 2016. PMID:26939864

  14. Isoniazid loaded gelatin-cellulose whiskers nanoparticles for controlled drug delivery applications

    Indian Academy of Sciences (India)

    MANDIP SARMAH; ANOWAR HUSSAIN; ANAND RAMTEKE; TARUN K MAJI

    2016-08-01

    Natural polymers like gelatin have been used as a potential drug carrier for controlled delivery applications due to their various advantages over synthetic polymers. Cellulose Whiskers (CWs) have the capacity to form strong hydrogen bonds which help in controlling the release of drug and also provide goodstrength to the drug carrier. In this report, CWs were prepared from filter paper cellulose by acid hydrolysis. Also, attempt was made to prepare gelatin-CWs nanoparticles by desolvation method using an anti-tuberculosis drug, isoniazid and a crosslinker glutaraldehyde (GA). The CWs and gelatin-CWs nanoparticles were characterized by X-ray diffractometry (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The effect of CWs on gelatin nanoparticlesover 8-hour period was measured in swelling studies. Efficiency of drug loading and subsequent release of isoniazid in buffer solutions at pH 1.2 (0.1N HCl) and pH 7.4 (phosphate buffer) were studied. Cytotoxicity study showed less toxicity for gelatin-CWs nanoparticles.

  15. Stainless steels and special grades for specific applications; Aciers inoxydables et nuances speciales pour applications specifiques

    Energy Technology Data Exchange (ETDEWEB)

    Dupoiron, F.; Verneau, M. [Societe des Forges et Ateliers du Creusot (SFAC), 75 - Paris (France)

    1994-12-31

    The development of special steels grades with a composition between stainless steels and nickel alloys for localised corrosion resistance applications (steam condenser, combustion products de-pollution...) are shortly presented by family (austenitic and super-austenitic stainless steels of the URANUS family with or without nitrogen additions, austeno-ferritic steels), with electrochemistry corrosion tests evaluation : in standard medium (30 g/l NaCl + 6% FeCl{sub 3}) or in real medium. (A.B.). 6 refs., 12 figs., 2 tabs.

  16. Tunnelling conductive hybrid films of gold nanoparticles and cellulose and their applications as electrochemical electrodes.

    Science.gov (United States)

    Liu, Zhiming; Wang, Xuefeng; Li, Mei; Wu, Wenjian

    2015-11-20

    Conductive hybrid films of metal nanoparticles and polymers have practical applications in the fields of sensing, microelectronics and catalysis, etc. Herein, we present the electrochemical availability of tunnelling conductive hybrid films of gold nanoparticles (GNPs) and cellulose.The hybrid films were provided with stable tunnelling conductive properties with 12 nm GNPs of 12.7% (in weight). For the first time, the conductive hybrid films were used as substrates of electrochemical electrodes to load calmodulin (CaM) proteins for sensing of calcium cations.The electrodes of hybrid films with 20 nm GNPs of 46.7% (in weight) exhibited stable electrochemical properties, and showed significant responses to calcium cations with concentrations as low as 10(−9) M after being loaded with CaM proteins. PMID:26511782

  17. Carboxymethyl Cellulose Acetate Butyrate: A Review of the Preparations, Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Mohamed El-Sakhawy

    2014-01-01

    Full Text Available Carboxymethyl cellulose acetate butyrate (CMCAB has gained increasing importance in several fields, particularly in coating technologies and pharmaceutical research. CMCAB is synthesized by esterification of CMC sodium salt with acetic and butyric anhydrides. CMCAB mixed esters are relatively high molecular weight (MW thermoplastic polymers with high glass transition temperatures (Tg. CMCAB ester is dispersible in water and soluble in a wide range of organic solvents, allowing varied opportunity to the solvent choice. It makes application of coatings more consistent and defect-free. Its ability to slow down the release rate of highly water-soluble compounds and to increase the dissolution of poorly soluble compounds makes CMCAB a unique and potentially valuable tool in pharmaceutical and amorphous solid dispersions (ASD formulations.

  18. Fabrication of bacterial cellulose-ZnO composite via solution plasma process for antibacterial applications.

    Science.gov (United States)

    Janpetch, Nattakammala; Saito, Nagahiro; Rujiravanit, Ratana

    2016-09-01

    Zinc oxide (ZnO) was successfully synthesized by applying a solution plasma, a plasma discharge in a liquid phase, without the addition of a reducing agent and simultaneously deposited into a bacterial cellulose pellicle that functioned as a template. By the reasons of its nano-sized structure as well as favorable porous configuration, the BC pellicle has been proved to be a splendid upholding template for the coordination of ZnO. In addition, the ZnO-deposited BC composites demonstrated strong antibacterial activity without a photocatalytic reaction against both Staphylococcus aureus and Escherichia coli. Hence, the ZnO-deposited BC composites can be used as an antibacterial material in wound dressing and water disinfection applications. PMID:27185147

  19. Couplage thermomécanique lors de la soudure par ultrasons : application pour les thermoplastiques

    OpenAIRE

    Ha Minh, Duc

    2009-01-01

    Cette thèse présente un couplage thermodynamique pour une modélisation approfondie du processus de soudure par ultrasons, surtout la soudure des thermoplastiques. Il s'agit de bien connaître le mode de fonctionnement des ensembles acoustiques réalisant la soudure ainsi que le comportement des matériaux à souder. En conséquence, les propriétés de ces matériaux, surtout celles nécessaires pour la modélisation par éléments finis, sont identifiées. Les paramètres mécaniques et thermiques sont mes...

  20. Textile lumineux en fibres optiques pour une application photocatalytique en phase gazeuse

    OpenAIRE

    Bourgeois, Pierre-Alexandre

    2011-01-01

    La pollution de l'air intérieur est un enjeu majeur pour la santé humaine. Pour réduire les concentrations de polluants des milieux confinés, notre étude s'est basée sur la conception et les tests d'un nouveau média photocatalytique innovant composé de textile rendu lumineux grâce à la présence de fibres optiques microstructurées. Le textile est rendu photocatalytique après ajout de TiO2 en suivant différentes méthodes de dépôt. Les fibres optiques ont alors deux rôles fondamentaux : première...

  1. Guides d'ondes infrarouges pour applications en télécommunications, capteurs chimiques et biochimiques

    Science.gov (United States)

    Smektala, F.; Bureau, B.; Adam, J. L.; Lucas, J.

    2002-06-01

    Les énergies de phonons élevés des verres à base de silice limitent leurs applications dans l'infrarouge. Il devient donc incontournable de créer des verres à plus faible énergie de phonons pour développer une optique passive guidée opérationnelle dans l'IR moyen et pour réaliser de nouveaux guide d'ondes optiques activés par des lanthanides pouvant jouer le rôle soit d'amplificateurs optiques soit de fibres lasers. Les compositions de verres stables répondant à ces critères sont exceptionnelles et appartiennent aux familles chimiques des fluorures et des chalcogénures. Les verres de fluorures, convenablement dopés par des terres rares, ont permis la réalisation d'amplificateurs optiques opérant dans la fenêtre télecom de la silice (1.3 μm avec le praséodyme, 1.45 μm avec le thulium et 1.55 μm avec l'erbium. Les verres de chalcogénures permettent la réalisation de fibres opérationnelles jusqu'à 12 μm mais seulement pour des applications courtes distances telles que le transport d'énergie moyenne, la radiométrie à l'ambiante et la spectrométrie IR déportée par fibre optique de molécules chimiques ou de tissus biologiques.

  2. Solid propellant micro thrusters for space application; Micropropulseur a propergol solide pour des applications spatiales

    Energy Technology Data Exchange (ETDEWEB)

    Larangot, B.; Rossi, C.; Esteve, D. [Laboratoire d' analyse et d' architecture des systemes (LAAS-CNRS), 31 - Toulouse (France); Orieux, S. [Laboratoire d' analyse et d' architecture des systemes (LAAS-CNRS/CNES), 31 - Toulouse (France)

    2003-07-01

    The paper presents the development of solid propellant micro thruster matrix on silicon. The concept is based on the pyrotechnic material combustion of propellant type stored in a micro machined silicon or Foturan tank. Each Thruster contains three parts: a thermal igniter, a tank and a nozzle. Due to the one shot characteristic, thrusters are fabricated in array configuration. The main field of application is the realization of micro propulsion modules for nano satellite. The micro thrusters array presented in this paper contains 16 individual thrusters on 64 mm{sup 2} surface. Each thruster has a combustion surface of 2.25 mm{sup 2} and throat diameters of 105 {mu}m and 150 {mu}m. The manufacturing process is described and preliminary ignition results and combustion rate are given. (authors)

  3. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO{sub 4} for lithium ion battery application

    Energy Technology Data Exchange (ETDEWEB)

    Nurhadini,, E-mail: nur-chem@yahoo.co.id; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Inorganic and Physical Chemistry Research Division, Faculty of Mathematics and Natural Sciences, Institiut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132 (Indonesia)

    2015-09-30

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO{sub 4} membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10{sup −4} S/cm was observed in SA/PEO/LiClO{sub 4} membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  4. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO4 for lithium ion battery application

    Science.gov (United States)

    Nurhadini, Arcana, I. Made

    2015-09-01

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO4 membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10-4 S/cm was observed in SA/PEO/LiClO4 membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application.

  5. Synthesis of polymer electrolyte membranes from cellulose acetate/poly(ethylene oxide)/LiClO4 for lithium ion battery application

    International Nuclear Information System (INIS)

    This study was conducted to determine the effect of cellulose acetate on poly(ethylene oxide)-LiClO4 membranes as the polymer electrolyte. Cellulose acetate is used as an additive to increase ionic conductivity and mechanical property of polymer electrolyte membranes. The increase the percentage of cellulose acetate in membranes do not directly effect on the ionic conductivity, and the highest ionic conductivity of membranes about 5,7 × 10−4 S/cm was observed in SA/PEO/LiClO4 membrane with cellulose ratio of 10-25% (w/w). Cellulose acetate in membranes increases mechanical strength of polymer electrolyte membranes. Based on TGA analysis, this polymer electrolyte thermally is stable until 270 °C. The polymer electrolyte membrane prepared by blending the cellulose acetate, poly(ethylene oxide), and lithium chlorate could be potentially used as a polymer electrolyte for lithium ion battery application

  6. A versatile method for producing functionalized cellulose nanofibers and their application

    Science.gov (United States)

    Huang, Pei; Zhao, Yang; Kuga, Shigenori; Wu, Min; Huang, Yong

    2016-02-01

    A facile method was developed to produce functionalized cellulose nanofibers in one step by ball milling. Through the synergy of mechanical and chemical actions, the produced cellulose nanofibers are ca. 20 nm wide and several micrometers long, with surface properties tailored by choice of modifying reagent. Modified by succinic anhydride, a cellulose nanofiber shows enhanced hydrophilicity, can be readily dispersed in water or DMSO, and gives a zeta potential of -38.7 mV due to carboxyl groups on the surface. Modified by dodecyl succinic anhydride, a cellulose nanofiber has excellent dispersibility in o-xylene and good compatibility with polyethylene. The polyethylene-cellulose nanofiber composite presents overall enhancement of mechanical properties. This method opens a new way to the production of functionalized cellulose nanofibers.A facile method was developed to produce functionalized cellulose nanofibers in one step by ball milling. Through the synergy of mechanical and chemical actions, the produced cellulose nanofibers are ca. 20 nm wide and several micrometers long, with surface properties tailored by choice of modifying reagent. Modified by succinic anhydride, a cellulose nanofiber shows enhanced hydrophilicity, can be readily dispersed in water or DMSO, and gives a zeta potential of -38.7 mV due to carboxyl groups on the surface. Modified by dodecyl succinic anhydride, a cellulose nanofiber has excellent dispersibility in o-xylene and good compatibility with polyethylene. The polyethylene-cellulose nanofiber composite presents overall enhancement of mechanical properties. This method opens a new way to the production of functionalized cellulose nanofibers. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08179c

  7. CELLULOSIC NANOCOMPOSITES: A REVIEW

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2008-08-01

    Full Text Available Because of their wide abundance, their renewable and environmentally benign nature, and their outstanding mechanical properties, a great deal of attention has been paid recently to cellulosic nanofibrillar structures as components in nanocomposites. A first major challenge has been to find efficient ways to liberate cellulosic fibrils from different source materials, including wood, agricultural residues, or bacterial cellulose. A second major challenge has involved the lack of compatibility of cellulosic surfaces with a variety of plastic materials. The water-swellable nature of cellulose, especially in its non-crystalline regions, also can be a concern in various composite materials. This review of recent work shows that considerable progress has been achieved in addressing these issues and that there is potential to use cellulosic nano-components in a wide range of high-tech applications.

  8. Cellulose nanocrystals in nanocomposite approach: Green and high-performance materials for industrial, biomedical and agricultural applications

    Science.gov (United States)

    Fortunati, E.; Torre, L.

    2016-05-01

    The need to both avoid wastes and find new renewable resources has led to a new and promising research based on the possibility to revalorize the biomass producing sustainable chemicals and/or materials which may play a major role in replacing systems traditionally obtained from non-renewable sources. Most of the low-value biomass is termed lignocellulosic, referring to its main constituent biopolymers: cellulose, hemicelluloses and lignin. In this context, nanocellulose, and in particular cellulose nanocrystals (CNC), have gain considerable attention as nanoreinforcement for polymer matrices, mainly biodegradable. Derived from the most abundant polymeric resource in nature and with inherent biodegradability, nanocellulose is an interesting nanofiller for the development of nanocomposites for industrial, biomedical and agricultural applications. Due to the high amount of hydroxyl groups on their surface, cellulose nanocrystals are easy to functionalize. Well dispersed CNC are able, in fact, to enhance several properties of polymers, i.e.: thermal, mechanical, barrier, surface wettability, controlled of active compound and/or drug release. The main objective here is to give a general overview of CNC applications, summarizing our recent developments of bio-based nanocomposite formulations reinforced with cellulose nanocrystals extracted from different natural sources and/or wastes for food packaging, medical and agricultural sectors.

  9. Research and Application of Bacterial Cellulose%细菌纤维素的研究及其应用

    Institute of Scientific and Technical Information of China (English)

    贾士儒; 刘淼; 薄涛

    2013-01-01

    As a novel nanomaterial ,bacterial cellulose ( BC ) has attracted more attention due to its high quality in mechanical strength ,biocompatibility and biodegradability .This paper introduces the domestic and international researches on the metabolism and biosynthesis mechanism of bacterial cellulose . Meanwhile ,the applications of bacterial cellulose in food ,paper making and biomedical materials etc .were presented.Finally, the furture research trends and application prospects of bacterial cellulose were discussed .%细菌纤维素作为新型纳米材料,具有极好的物理特性、生物相容性和生物可降解性等。本文介绍了国内外目前对细菌纤维素代谢及生物合成机制的研究现状,及细菌纤维素在食品、造纸和医学等领域的应用。并展望了细菌纤维素未来的研究趋势与应用前景。

  10. Exploring biosensor applications with cotton cellulose nanocrystalline protein and peptide conjugates

    Science.gov (United States)

    Sensor I: Nano-crystalline preparations were produced through acid hydrolysis and mechanical breakage of the cotton fibers from a scoured and bleached cotton fabric and a scoured and bleached, mercerized fabric, which was shown to produce cellulose I (NCI) and cellulose II (NCII) crystals respective...

  11. Titanium dioxide–cellulose hybrid nanocomposite and its glucose biosensor application

    International Nuclear Information System (INIS)

    Highlights: ► An organic–inorganic hybrid nanocomposite was fabricated by blending TiO2 nanoparticles and cellulose solution. ► The hybrid nanocomposite has advantages of biodegradability and bio-compatibility of cellulose and physical properties of TiO2. ► Enzyme glucose oxidase (GOx) was immobilized into the hybrid nanocomposite and covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. ► Linear response of the glucose biosensor was obtained in the range of 1–10 mM. - Abstract: This paper investigates the fabrication of titanium dioxide (TiO2)–cellulose hybrid nanocomposite and its possibility for a conductometric glucose biosensor. TiO2 nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N,N-dimethylacetamide solvent to fabricate TiO2–cellulose hybrid nanocomposite. The enzyme, glucose oxidase (GOx) was immobilized into this hybrid nanocomposite by physical adsorption method. The successful immobilization of glucose oxidase into TiO2–cellulose hybrid nanocomposite via covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of the glucose biosensor is obtained in the range of 1–10 mM. This study demonstrates that TiO2–cellulose hybrid nanocomposite can be a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

  12. Actionneur linéaire intégré pour application domotique

    OpenAIRE

    Ben Ahmed, Hamid; Multon, Bernard; Prevond, Laurent; Lucidarme, Jean

    2000-01-01

    National audience D'une manière générale, les entraînements électriques pour la domotique requièrent une grande discrétion aussi bien sonore que visuelle (et donc une forte intégration dans leur environnement), un faible coût et enfin une fiabilité élevée tant au niveau du fonctionnement que de celui de la sécurité des personnes (normes d'isolation électrique). D'autre part, Ces entraînements ne sont appelés à fonctionner que quelques minutes par jour. De ce fait, le rendement énergétique ...

  13. Study on time management of FCD concrete pouring AP1000 NPP and its application

    International Nuclear Information System (INIS)

    Haiyang nuclear power plant adopts the advanced third-generation nuclear power technology, AP1000, the design concept of passive system and the methods of modularization and 'open-top' construction greatly shortens the construction period. At the same time, higher requirements are put forward to the management of construction, quality and progress control. This paper will apply the statistical process control theory and method to the time management of FCD (First Concrete Day) to Unit 1 of Haiyang AP1000 nuclear power plant, and it brings up the mathematical model of time management based on verification through modeling, data analysis, model optimization and the actual construction work. The theory and method studied in this paper can not be only applied to the FCD concrete pouring for Unit 1 of Haiyang AP1000 nuclear power plant, but also have great referential and guiding significance to the continuous concreting of the mass concrete of the follow-up similar construction. (authors)

  14. Commande des bras manipulateurs et retour visuel pour des applications à la robotique de service

    OpenAIRE

    Herrera-Aguilar, Ignacio

    2007-01-01

    Dans le contexte de la robotique de service, les robots doivent interagir avec l'environnement et les humains qui s'y trouvent. La présence d'humain crée un contexte particulier où la sécurité et le confort des utilisateurs prime sur la dynamique du système. L'environnement n'étant pas figé dans ce contexte, l'utilisation de capteurs extéroceptifs est indispensable. Un premier thème développé dans le mémoire est la planification de trajectoires pour laquelle nous proposons de borner la vitess...

  15. Cartographie interactive historique pour informer sur les risques : application avec le DICRIM de la Ville de Saint-Étienne

    OpenAIRE

    Chesneau, Élisabeth; Clément, Adeline; Lieghio, Éric

    2014-01-01

    Une commune soumise à des risques majeurs comme des inondations a pour obligation de réaliser un Document d'Information Communal sur les Risques Majeurs. Une partie des informations à communiquer concerne les événements historiques ayant eu lieu sur le territoire. La carte constitue un vecteur essentiel pour spatialiser ces données. En 2011, la Ville de Saint-Étienne, l'Institut des Risques Majeurs de Grenoble et l’UMR EVS ont développé une application cartographique interactive sur l'histoir...

  16. Technologies émergentes de mémoire résistive pour les systèmes et application neuromorphique

    OpenAIRE

    Suri, Manan,

    2013-01-01

    La recherche dans le domaine de l’informatique neuro-inspirée suscite beaucoup d'intérêt depuis quelques années. Avec des applications potentielles dans des domaines tels que le traitement de données à grande échelle, la robotique ou encore les systèmes autonomes intelligents pour ne citer qu'eux, des paradigmes de calcul bio-inspirés sont étudies pour la prochaine génération solutions informatiques (post-Moore, non-Von Neumann) ultra-basse consommation. Dans ce travail, nous discutons les rô...

  17. APPLICATION DE LA VEILLE ANTICIPATIVE STRATEGIQUE POUR LE SUIVI DE L’ENVIRONMENT ET LA PRODUCTION DE CONNAISSANCES ACTIONABLES

    OpenAIRE

    Raquel Janissek-Muniz; Fábio Dídimo Becker; Humbert Lesca; Henrique Freitas

    2011-01-01

    Cet article propose un usage innovant de la méthode L.E.SCAnning® pour le suivi de l’environnent. Avec une étude de cas, conduite dans une entreprise brésilienne, ayant comme domaine d’application l'évaluation des actions disponibles sur le marché, nous avons cherché à interpréter de futurs scénarios. La méthodologie est basée sur la recherche qualitative exploratoire, en utilisant des informations collectées. Les informations ont été organisées par cible puis regroupées par affinité (Méthode...

  18. 纤维素生物活性材料的种类及应用%The types and application of cellulosic Materials with biological activity

    Institute of Scientific and Technical Information of China (English)

    柳春; 宁玉娟; 史磊; 蓝丽; 陈专; 吕旷

    2013-01-01

    纤维素的功能化一直是人们研究的热点,近年来又涌现出一批以纤维素为基准的具有生物性的活性材料。文章主要论述了以纤维素为基准的细菌纤维素、复合材料、纤维素硫酸钠材料等具有生物活性材料的种类与应用。%Cellulose functional materials has been a challenge for researchers, this year has emerged a group of cellulose as the biological function of the substrate material. This paper summarizes the types and application of the bacterial cellulose, cellulose-based, composite materials, and sodium cellulose with biological materials.

  19. Biosynthesis of Bacterial Cellulose/Carboxylic Multi-Walled Carbon Nanotubes for Enzymatic Biofuel Cell Application

    Directory of Open Access Journals (Sweden)

    Pengfei Lv

    2016-03-01

    Full Text Available Novel nanocomposites comprised of bacterial cellulose (BC with carboxylic multi-walled carbon nanotubes (c-MWCNTs incorporated into the BC matrix were prepared through a simple method of biosynthesis. The biocathode and bioanode for the enzyme biological fuel cell (EBFC were prepared using BC/c-MWCNTs composite injected by laccase (Lac and glucose oxidase (GOD with the aid of glutaraldehyde (GA crosslinking. Biosynthesis of BC/c-MWCNTs composite was characterized by digital photos, scanning electron microscope (SEM, and Fourier Transform Infrared (FTIR. The experimental results indicated the successful incorporation of c-MWCNTs into the BC. The electrochemical and biofuel performance were evaluated by cyclic voltammetry (CV and linear sweep voltammetry (LSV. The power density and current density of EBFCs were recorded at 32.98 µW/cm3 and 0.29 mA/cm3, respectively. Additionally, the EBFCs also showed acceptable stability. Preliminary tests on double cells indicated that renewable BC have great potential in the application field of EBFCs.

  20. Properties and application of bacterial cellulose%细菌纤维素特性及其应用

    Institute of Scientific and Technical Information of China (English)

    吕鸿皓; 夏秀芳; 党苗苗; 费楠; 王英男; 吴磊

    2015-01-01

    细菌纤维素(Bacterial Cellulose, BC),是由细菌产生的胞外产物,因由细菌产生,故其命名为细菌纤维素。细菌纤维素因其具有高持水性、高结晶度、超细纳米纤维网络、高弹性模量和抗拉强度等独特的性质,而被广泛地应用在食品及医学中。本文综述了细菌纤维素在食品、新型伤口敷料、人体组织材料、人工角膜和心脏瓣膜、药物结合或释放以及医用产品开发新兴领域的应用和发展前景。细菌纤维素生产出的产品不仅口感美味,而且作为健康食品,可降低人体胆固醇而拥有保健价值。医学方面期望细菌纤维素能够依据其独特的性质在更广泛的领域得到长足发展。相信在不久的将来,日益完善的生产技术能让细菌纤维素更好地为人类服务。%Bacterial Cellulose (BC for short), is a product produced by bacteria extracellularly, so named Bacterial Cellulose. Bacterial Cellulose is widely used in food and medicine because of its unique properties, such as high water holding capacity, high crystallinity, nanofibre-network structure, high elastic modulus and tensile strength. This article briefly summarizes the recent developments and applications of bacterial cellulose in the food, emerging field of novel wound dressing, human tissue materials, artificial cornea and heart valves, the drug combination or release, and medical products. Products of BC is not only delicious, but also as a health food, have lower cholesterol levels and health care value. Medicine of bacterial cellulose is expected in the broader field to get a long-term development according to its unique properties. In the near future, the increasingly perfect production technology can make bacterial cellulose serve humans better.

  1. Microfibrillated cellulose: Energy-efficient preparation techniques and applications in paper

    OpenAIRE

    Ankerfors, Mikael

    2015-01-01

    This work describes three alternative processes for producing microfibrillated cellulose (MFC; also referred to as cellulose nanofibrils, CNF) in which bleached pulp fibres are first pretreated and then homogenized using a high-pressure homogenizer. In one process, fibre cell wall delamination was facilitated by a combined enzymatic and mechanical pretreatment. In the two other processes, cell wall delamination was facilitated by pretreatments that introduced anionically charged groups into t...

  2. Titanium dioxide-cellulose hybrid nanocomposite and its glucose biosensor application

    Energy Technology Data Exchange (ETDEWEB)

    Maniruzzaman, Mohammad; Jang, Sang-Dong [Center for EAPap Actuator, Department of Mechanical Engineering, INHA University, Incheon 402-751 (Korea, Republic of); Kim, Jaehwan, E-mail: jaehwan@inha.ac.kr [Center for EAPap Actuator, Department of Mechanical Engineering, INHA University, Incheon 402-751 (Korea, Republic of)

    2012-06-25

    Highlights: Black-Right-Pointing-Pointer An organic-inorganic hybrid nanocomposite was fabricated by blending TiO{sub 2} nanoparticles and cellulose solution. Black-Right-Pointing-Pointer The hybrid nanocomposite has advantages of biodegradability and bio-compatibility of cellulose and physical properties of TiO{sub 2}. Black-Right-Pointing-Pointer Enzyme glucose oxidase (GOx) was immobilized into the hybrid nanocomposite and covalent bonding between TiO{sub 2} and GOx was confirmed by X-ray photoelectron analysis. Black-Right-Pointing-Pointer Linear response of the glucose biosensor was obtained in the range of 1-10 mM. - Abstract: This paper investigates the fabrication of titanium dioxide (TiO{sub 2})-cellulose hybrid nanocomposite and its possibility for a conductometric glucose biosensor. TiO{sub 2} nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N,N-dimethylacetamide solvent to fabricate TiO{sub 2}-cellulose hybrid nanocomposite. The enzyme, glucose oxidase (GOx) was immobilized into this hybrid nanocomposite by physical adsorption method. The successful immobilization of glucose oxidase into TiO{sub 2}-cellulose hybrid nanocomposite via covalent bonding between TiO{sub 2} and GOx was confirmed by X-ray photoelectron analysis. The linear response of the glucose biosensor is obtained in the range of 1-10 mM. This study demonstrates that TiO{sub 2}-cellulose hybrid nanocomposite can be a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

  3. Characterization of TEMPO-oxidized bacterial cellulose scaffolds for tissue engineering applications

    International Nuclear Information System (INIS)

    Introduction of active groups on the surface of bacterial cellulose (BC) nanofibers is one of the promising routes of tailoring the performance of BC scaffolds for tissue engineering. This paper reported the introduction of aldehyde groups to BC nanofibers by 2,2,6,6-tetramethylpyperidine-1-oxy radical (TEMPO)-mediated oxidation and evaluation of the potential of the TEMPO-oxidized BC as tissue engineering scaffolds. Periodate oxidation was also conducted for comparison. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses were carried out to determine the existence of aldehyde groups on BC nanofibers and the crystallinity. In addition, properties relevant to scaffold applications such as morphology, fiber diameter, mechanical properties, and in vitro degradation were characterized. The results indicated that periodate oxidation could introduce free aldehyde to BC nanofibers and the free aldehyde groups on the TEMPO-oxidized BC tended to transfer to acetal groups. It was also found that the advantageous 3D structure of BC scaffolds remained unchanged and that no significant changes in morphology, fiber diameter, tensile structure and in vitro degradation were found after TEMPO-mediated oxidation while significant differences were observed upon periodate oxidation. The present study revealed that TEMPO-oxidation could impart BC scaffolds with new functions while did not degrade their intrinsic advantages. - Highlights: • TEMPO-mediated oxidation on BC scaffold for tissue engineering use was conducted. • TEMPO-mediated oxidation did not degrade the intrinsic advantages of BC scaffold. • TEMPO-mediated oxidation could impart BC scaffold with new functional groups. • Feasibility of TEMPO-oxidized BC as tissue engineering scaffold was confirmed

  4. Bacterial cellulose membrane produced by Acetobacter sp. A10 for burn wound dressing applications.

    Science.gov (United States)

    Kwak, Moon Hwa; Kim, Ji Eun; Go, Jun; Koh, Eun Kyoung; Song, Sung Hwa; Son, Hong Joo; Kim, Hye Sung; Yun, Young Hyun; Jung, Young Jin; Hwang, Dae Youn

    2015-05-20

    Bacteria cellulose membranes (BCM) are used for wound dressings, bone grafts, tissue engineering, artificial vessels, and dental implants because of their high tensile strength, crystallinity and water holding ability. In this study, the effects of BCM application for 15 days on healing of burn wounds were investigated based on evaluation of skin regeneration and angiogenesis in burn injury skin of Sprague-Dawley (SD) rats. BCM showed a randomly organized fibrils network, 12.13 MPa tensile strength, 12.53% strain, 17.63% crystallinity, 90.2% gel fraction and 112.14 g × m(2)/h highest water vapor transmission rate (WVTR) although their swelling ratio was enhanced to 350% within 24h. In SD rats with burned skin, the skin severity score was lower in the BCM treated group than the gauze (GZ) group at all time points, while the epidermis and dermis thickness and number of blood vessels was greater in the BCM treated group. Furthermore, a significant decrease in the number of infiltrated mast cells and in vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) expression was observed in the BCM treated group at day 10 and 15. Moreover, a significant high level in collagen expression was observed in the BCM treated group at day 5 compared with GZ treated group, while low level was detected in the same group at day 10 and 15. However, the level of metabolic enzymes representing liver and kidney toxicity in the serum of BCM treated rats was maintained at levels consistent with GZ treated rats. Overall, BCM may accelerate the process of wound healing in burn injury skin of SD rats through regulation of angiogenesis and connective tissue formation as well as not induce any specific toxicity against the liver and kidney. PMID:25817683

  5. Characterization of TEMPO-oxidized bacterial cellulose scaffolds for tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Honglin [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Xiong, Guangyao [School of Mechanical and Electrical Engineering, East China Jiaotong University, Nanchang, Jiangxi 330013 (China); Hu, Da [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Ren, Kaijing [Department of Joint Surgery, Tianjin Hospital, Tianjin 300211 (China); Yao, Fanglian; Zhu, Yong [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Gao, Chuan [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Wan, Yizao, E-mail: yzwantju@126.com [School of Materials Science and Engineering, Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2013-12-16

    Introduction of active groups on the surface of bacterial cellulose (BC) nanofibers is one of the promising routes of tailoring the performance of BC scaffolds for tissue engineering. This paper reported the introduction of aldehyde groups to BC nanofibers by 2,2,6,6-tetramethylpyperidine-1-oxy radical (TEMPO)-mediated oxidation and evaluation of the potential of the TEMPO-oxidized BC as tissue engineering scaffolds. Periodate oxidation was also conducted for comparison. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses were carried out to determine the existence of aldehyde groups on BC nanofibers and the crystallinity. In addition, properties relevant to scaffold applications such as morphology, fiber diameter, mechanical properties, and in vitro degradation were characterized. The results indicated that periodate oxidation could introduce free aldehyde to BC nanofibers and the free aldehyde groups on the TEMPO-oxidized BC tended to transfer to acetal groups. It was also found that the advantageous 3D structure of BC scaffolds remained unchanged and that no significant changes in morphology, fiber diameter, tensile structure and in vitro degradation were found after TEMPO-mediated oxidation while significant differences were observed upon periodate oxidation. The present study revealed that TEMPO-oxidation could impart BC scaffolds with new functions while did not degrade their intrinsic advantages. - Highlights: • TEMPO-mediated oxidation on BC scaffold for tissue engineering use was conducted. • TEMPO-mediated oxidation did not degrade the intrinsic advantages of BC scaffold. • TEMPO-mediated oxidation could impart BC scaffold with new functional groups. • Feasibility of TEMPO-oxidized BC as tissue engineering scaffold was confirmed.

  6. CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE

    Institute of Scientific and Technical Information of China (English)

    Yun Chen; Xiao-peng Xiong; Guang Yang; Li-na Zhang; Sen-lin Lei; Hui Lianga

    2002-01-01

    A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzedin 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree ofsubstitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration,Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differentialscanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes wasslightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability weresignificantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept thegood pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity andthermostability. Therefore, the application range of cellulose acetate membranes can be expanded.

  7. Electron beam application as pre treatment of sugar cane bagasse to enzymatic hydrolysis of cellulose

    International Nuclear Information System (INIS)

    Due to increasing worldwide shortage of food and energy sources, sugarcane bagasse has been considered as a substrate for single cell protein, animal feed, and renewable energy production. Sugarcane bagasse generally contain up to 45% glucose polymer cellulose, much of which is in a crystalline structure, 40% hemicelluloses, an amorphous polymer usually composed of xylose, arabinose, galactose, glucose, and mannose and 20% lignin, which cannot be easily separated into readily usable components due to their recalcitrant nature. Pure cellulose is readily depolymerised by radiation, but in biomass the cellulose is intimately bonded with lignin, that protect it from radiation effects. The objective of this study was the evaluation of the electron beam irradiation efficiency as a pre-treatment to enzymatic hydrolysis of cellulose in order to facilitate its fermentation and improves the production of ethanol biofuel. Samples of sugarcane bagasse were obtained in sugar/ethanol Mill sited in Piracicaba, Brazil, and were irradiated using Radiation Dynamics Electron Beam Accelerator with 1,5 MeV energy and 37 kW, in batch systems. The applied absorbed doses of the fist sampling, Bagasse A, were 20 kGy, 50 kGy, 10 0 kGy and 200 kGy. After the evaluation the preliminary obtained results, it was applied lower absorbed doses in the second assay: 5 kGy, 10 kGy, 20 kGy, 30 kGy, 50 kGy, 70 kGy, 100 kGy and 150 kGy. The electron beam processing took to changes in the sugarcane bagasse structure and composition, lignin and cellulose cleavage. The yield of enzymatic hydrolyzes of cellulose in. (author)

  8. Fermentation Tecniques and Applications of Bacterial Cellulose: a Review Técnicas de fermentación y aplicaciones de la celulosa bacteriana: una revisión

    OpenAIRE

    Luz Dary Carreño Pineda; Luis Alfonso Caicedo Mesa; Carlos Arturo Martínez Riascos

    2012-01-01

    Bacterial cellulose is a polymer obtained by fermentation with microorganismsfrom Acetobacter, Rhizobium, Agrobacterium and Sarcina genera. Amongthem, Acetobacter xylinum is the most efficient specie. This polymer hasthe same chemical composition of plant cellulose, but its conformation andphysicochemical properties are different, making it attractive for several applications, especially in the areas of food, separation processes, catalysis andhealth, due to its biocompatibility. However, the ma...

  9. APPLICATION OF FILLERS IN CELLULOSIC PAPER BY SURFACE FILLING: AN INTERESTING ALTERNATIVE OR SUPPLEMENT TO WET-END ADDITION

    Directory of Open Access Journals (Sweden)

    Jing Shen,

    2012-01-01

    Full Text Available The application of fillers at the surface of cellulosic paper is an interesting and industrially-commercialized but not very well-known concept, in which the filler particles are essentially added to the voids of the fibrous matrixes. This so-called “surface filling” can be achieved by the use of fillers together with a polymer solution via film press or size press, an approach that is distinct from both wet-end filling and conventional coating of paper. As an easily practicable process, surface filling has some advantages over direct wet-end addition of fillers, such as minimizing the adverse effects of filler addition on paper strength. Efficient surface filling is somewhat dependent on the specific characteristics of both fillers and fibrous matrixes. Surface filling may provide interesting possibilities for the papermaking discipline; for example, it would open the door to maximizing the cost-effectiveness of paper mills, and efficiently adding new functionalities to cellulosic paper. From both practical and fundamental points of view, systematic exploration and understanding of surface filling of cellulosic paper would be of great significance to the papermaking industry.

  10. Synthesis of bis-monochlorotriazine reactive dyes and their application on cellulose fiber

    International Nuclear Information System (INIS)

    Reactive dyes were synthesized from cyanuric chloride and 1-amino-8-hydroxy-naphthalene-3-6-disulphonic acid by condensation, diazotization, activation and coupling reaction. The colorimetric properties and fastness of these dyes were measured. The influence of diamine-bridge which joins two chromophore systems on the degree of dye exhaustion from the dye bath was examined. The synthesized dyes exhibited very good dye properties. When applied to the material especially cellulose, provided strong red to bluish-red shades having very good fastness properties and they were also characterized by high water solubility due to the presence of many salts forming groups. 4,4'-Bis-diaminostilbene-2,2'-disulphonic acid, 1,3-phenylene diamine, 1-4 phenylene diamine are used as bridging group. The dyes applied to cellulose fibers are practically combined with them by a covalent bond in a quantitative manner. These dyes are practically combined with cellulose fibers by a covalent bond in a quantitative manner. The degree of bonding with the fibers increases due to the bridging effect which results an increase in the dye affinity towards cellulose fibers. (author)

  11. Characteristics and application of microfibrillated cellulose. Bisho fiburiru ka serurosu no tokucho to sono yoto

    Energy Technology Data Exchange (ETDEWEB)

    Miyakawa, A. (Daicel Chemical Industries Ltd., Osaka (Japan))

    1992-10-10

    As the methods to refine or fibrillate cellulose fibers, there are the mechanical treatment, the physical treatment such as explosion, etc., and the chemical treatment such as microcrystallization, etc. In this article,, the technique to microfibrillate cellulose fibers using the high pressure homogenizer, which Daicel Chemical Industries Ltd. introduced from America ITT Leonia Co., and the features as well as use of the merchandise called Cellish, manufactured by this method are introduced. In order to microfibrillate fibers with the above device, the pressure of the aqueous suspension of raw cellulose is raised with a piston pump to several hundred kg/cm [sup 2], and the pressurized suspension is let to pass through an extremely narrow slit at more than 200m/s, then the pressure is reduced to the atmospheric pressure. Cellish has its minimum diameter of 0.01[mu]m and its surface area becomes more than 200 times bigger, since its raw cellulose fiber is split into about forty to eighty thousand pieces. Cellish is not water soluble, but has viscosity and very small adhesion, hence under no outer force, it shows the automorphic property. Its water retentivity is good and it is used as a filter and various additives. 12 refs., 8 figs., 2 tabs.

  12. Architecture Logicielles pour des Applications h\\'et\\'erog\\`enes, distribu\\'ees et reconfigurables

    OpenAIRE

    Louberry, Christine; Dalmau, Marc; Roose, Philippe

    2008-01-01

    The recent apparition of mobile wireless sensor aware to their physical environment and able to process information must allow proposing applications able to take into account their physical context and to react according to the changes of the environment. It suppose to design applications integrating both software and hardware components able to communicate. Applications must use context information from components to measure the quality of the proposed services in order to adapt them in rea...

  13. Interactions of microfibrillated cellulose and cellulosic fines with cationic polyelectrolytes

    OpenAIRE

    Taipale, Tero

    2010-01-01

    The overall aim of this work was to produce and characterize different types of cellulosic fines and microfibrillated cellulose; to study their interactions with high molar mass cationic polyelectrolytes; and to demonstrate novel examples of their utilization. The work was performed, and its results discussed mainly from papermaking point of view, but the results are also well applicable in other fields of industry. Cellulosic fines are an essential component of papermaking fiber suspens...

  14. APPLICATION DE LA VEILLE ANTICIPATIVE STRATEGIQUE POUR LE SUIVI DE L’ENVIRONMENT ET LA PRODUCTION DE CONNAISSANCES ACTIONABLES

    Directory of Open Access Journals (Sweden)

    Raquel Janissek-Muniz

    2011-08-01

    Full Text Available Cet article propose un usage innovant de la méthode L.E.SCAnning® pour le suivi de l’environnent. Avec une étude de cas, conduite dans une entreprise brésilienne, ayant comme domaine d’application l'évaluation des actions disponibles sur le marché, nous avons cherché à interpréter de futurs scénarios. La méthodologie est basée sur la recherche qualitative exploratoire, en utilisant des informations collectées. Les informations ont été organisées par cible puis regroupées par affinité (Méthode Puzzle. Ce travail cherche à démontrer que, en appliquant la méthode sur le marché d'actions, il est possible de produire des connaissances actionnables, et de construire, voire anticiper, des représentations futures

  15. Effect of Gamma Irradiation on Microbial Cellulose Membrane For Application In Guided Bone Regeneration (GBR)

    International Nuclear Information System (INIS)

    The synthesis and effect of gamma irradiation on characteristics of microbial cellulose membrane have been evaluated. Microbial cellulose gel (nata de coco) was produce using bacteria Acetobacter xylinum incubated in bacterial growth medium containing coconut water as a micro nutrient source. Microbial cellulose membrane was prepared using mould compression at 120°C for 5 minutes. The membranes were irradiated using gamma rays with doses of 25 and 50 kGy respectively at dose rate of 10 kGy/h. Several parameters such as water absorption, surface morphology, thermal and mechanical properties of un-irradiated and irradiated membranes were analyzed. The results showed that optimum production of microbial cellulose by A. Xylinum is 10 to 12 days at incubation temperature of 30°C and pH 4. Chemically treatments of MC membrane by NaOH and NaOCl solution were effective to remove the bacteria contaminant, bacterial cells embedded in the polymer net and endotoxin which occurred during cellulose production as well as produced membrane with more white colour. Water absorption properties of MC membranes showed maximum value at immersion temperature of 25°C, 37°C and 50°C were 110, 137 and 140 %, respectively. Water absorption of MC membrane decreases by increasing irradiation dose. Microscopic photograph of MC membrane showed that the membrane was consisted of interconnected nano to micro porous structures with diameter ranging from 0.05 to 0.5 μm. Thermal properties of MC showed that decomposition temperature of un-irradiated and irradiated MC membrane at dose of 25 and 50 kGy were 328°C, 328°C and 295°C, respectively. Tensile strength of un-irradiated MC membrane in dry state was 102 MPa. Irradiation at 25 and 50 kGy reduced tensile strength to become 85 and 51 MPa respectively. The decrease of thermal property and mechanical strength of MC membrane by irradiation is due to decomposition of polymeric cellulose to the lower molecular weight. This degradation hopefully

  16. Polyethylenimine coated bacterial cellulose nanofiber membrane and application as adsorbent and catalyst.

    Science.gov (United States)

    Wang, Jianqiang; Lu, Xinkun; Ng, Pui Fai; Lee, Ka I; Fei, Bin; Xin, John H; Wu, Jian-yong

    2015-02-15

    Bacterial cellulose (BC) nanofiber membranes were simply aminalized by a flush-coating and post-crosslinking method. Firstly, wet BC membranes were flushed through by an aqueous solution of polyethylenimine (PEI) and glycerol diglycidyl ether (GDE) under vacuum suction, then further heated up to 70 °C to crosslink the resultant coating on the surface of the nanofibers. The PEI coated bacterial cellulose (BC@PEI) nanofiber membrane presented excellent adsorption performance for Cu(2+) and Pb(2+) ions from aqueous solutions. Desorption of these ions was achieved using ethylene diamine tetraacetic acid treatment. This cycle of adsorption and desorption was repeated for several times with good remain adsorption performance (over 90%). Furthermore, the adsorbed Cu(2+) ions can be reduced to copper nanoparticles, and showed excellent catalytic performance for methylene blue reduction in aqueous solution. The catalytic performance can remained after several times of usage. PMID:25460686

  17. Biosynthesis of Bacterial Cellulose/Carboxylic Multi-Walled Carbon Nanotubes for Enzymatic Biofuel Cell Application

    OpenAIRE

    Pengfei Lv; Quan Feng; Qingqing Wang; Guohui Li; Dawei Li; Qufu Wei

    2016-01-01

    Novel nanocomposites comprised of bacterial cellulose (BC) with carboxylic multi-walled carbon nanotubes (c-MWCNTs) incorporated into the BC matrix were prepared through a simple method of biosynthesis. The biocathode and bioanode for the enzyme biological fuel cell (EBFC) were prepared using BC/c-MWCNTs composite injected by laccase (Lac) and glucose oxidase (GOD) with the aid of glutaraldehyde (GA) crosslinking. Biosynthesis of BC/c-MWCNTs composite was characterized by digital photos, scan...

  18. Cellulose Nanocrystals Obtained from Cynara Cardunculus and Their Application in the Paper Industry

    Directory of Open Access Journals (Sweden)

    Valentina Coccia

    2014-08-01

    Full Text Available Biorefinery aims at designing new virtuous and high-efficiency energy chains, achieving the combined production of biofuels (e.g., bioethanol and biobased products. This emerging philosophy can represent an important opportunity for the industrial world, exploiting a new kind of nano-smart biomaterials in their production chains. This paper will present the lab experience carried out by the Biomass Research Centre (CRB in extracting cellulose nanocrystals (NCC from a pretreated (via Steam Explosion fraction of Cynara cardunculus. This is a very common and invasive arboreal variety in central Italy. The NCC extraction methodology allows the separation of the crystalline content of cellulose. Such a procedure has been considered in the literature with the exception of one step in which the conditions have been optimized by CRB Lab. This procedure has been applied for the production of NCC from both Cynara cardunculus and microcrystalline cellulose (MCC. The paper will discuss some of the results achieved using the obtained nanocrystals as reinforcing filler in a paper sheet; it was found that the tensile strength increased from 3.69 kg/15 mm to 3.98 kg/15 mm, the durability behavior (measured by bending number changed from the value 95 to the value 141, and the barrier properties (measured by Gurley porosity were improved, increasing from 38 s to 45 s.

  19. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Directory of Open Access Journals (Sweden)

    Mehmet Isik

    2014-07-01

    Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels.

  20. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did...

  1. Photonique intégrée nonlinéaire sur plate-formes CMOS compatibles pour applications du proche au moyen infrarouge

    OpenAIRE

    Carletti, Luca

    2015-01-01

    La photonique intégrée offre la possibilité d’exploiter un vaste bouquet de phénomènes optique nonlinéaires pour la génération et le traitement de signaux optiques sur des puces très compactes et à des débits potentiels extrêmement rapides. De nouvelles solutions et technologies de composants pourraient être ainsi réalisées, avec un impact considérable pour les applications télécom et datacom. L’utilisation de phénomènes optiques nonlinéaires (e.g. effet Kerr optique, effet Raman) permet même...

  2. Matériaux solide conducteur thermodurcissable : Application aux plaques bipolaires pour pile à combustible

    OpenAIRE

    Dessertenne, Estelle

    2012-01-01

    Among the new technologies for energy for sustainable development, PEM fuel cells offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. While metal bipolar plates are penalized by their corrosion resistance and those based on graphite by their mechanical properties and cost (due to machining phases of the channels), the composite bipolar plates appear attractive be...

  3. Extraction biotechnologique de la chitine pour la production de chitosane : caractérisation et application

    OpenAIRE

    Pacheco Lopez, Neith

    2010-01-01

    The chitin is one of the most abundant biopolymers in biomass. Its main industrial derivative is the chitosan. These two polysaccharides present an increasing interest thanks to their various interesting physicochemical and biological properties. Their potential applications concern diverse fields as the pharmacy, medicine, food industry and agriculture. Despite numerous advances in methods for the chemical production of chitin and chitosan, the use of concentrated solutions of acids and alka...

  4. Amelioration de la precision d'un bras robotise pour une application d'ebavurage

    Science.gov (United States)

    Mailhot, David

    Process automation is a more and more referred solution when it comes to complex, tedious or even dangerous tasks for human. Flexibility, low cost and compactness make industrial robots very attractive for automation. Even if many developments have been made to enhance robot's performances, they still can not meet some industries requirements. For instance, aerospace industry requires very tight tolerances on a large variety of parts, which is not what robots were designed for at first. When it comes to robotic deburring, robot imprecision is a major problem that needs to be addressed before it can be implemented in production. This master's thesis explores different calibration techniques for robot's dimensions that could overcome the problem and make the robotic deburring application possible. Some calibration techniques that are easy to implement in production environment are simulated and compared. A calibration technique for tool's dimensions is simulated and implemented to evaluate its potential. The most efficient technique will be used within the application. Finally, the production environment and requirements are explained. The remaining imprecision will be compensated by the use of a force/torque sensor integrated with the robot's controller and by the use of a camera. Many tests are made to define the best parameters to use to deburr a specific feature on a chosen part. Concluding tests are shown and demonstrate the potential use of robotic deburring. Keywords: robotic calibration, robotic arm, robotic precision, robotic deburring

  5. Fabrication and characterization of novel biomimetic PLLA/cellulose/hydroxyapatite nanocomposite for bone repair applications

    International Nuclear Information System (INIS)

    The purpose of this research is to develop and characterize a novel biomimetic nanocomposite that closely mimics the properties of real bone such as morphology, composition and mechanical characteristics. This novel porous nanocomposite is composed of cotton-sourced cellulose microcrystals, hydroxyapatite nanoparticles and poly L-lactide acid. A unique combination of commonly used fabrication procedures has been developed including pre-treatment of particles using a coupling agent. The effect of various weight ratios of the reinforcing agents was evaluated to assess their influence on the chemical, thermal, and mechanical properties of the nanocomposites. The prepared nanocomposites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and compression testing. Our results indicated the presence of molecular interactions between all components leading to an increase of the crystallinity of the polymer from 50% to 80%. Compression test results revealed that increasing the weight ratio of microcrystalline cellulose/poly L-lactide acid and hydroxyapatite/poly L-lactide acid from 0.1 to 0.5 enhanced the compressive yield stress from 0.127 to 2.2 MPa and The Young's modulus from 6.6 to 38 MPa, respectively. It was found that the fabricated nanocomposites are comparable with the trabecular bone from compositional, structural, and mechanical point of view. - Highlights: • Fabrication of PLLA/HA/cellulose composites that mimic the spongeous bone • Homogenous dispersion of the reinforcing agents in the PLLA matrix was attained. • More efficient interface between the PLLA and the reinforcing agents was achieved. • Preliminary in vitro biocompatibility test showed the nontoxicity of the composite. • The crystallinity, the compressive strength and modulus were investigated

  6. Fabrication and characterization of novel biomimetic PLLA/cellulose/hydroxyapatite nanocomposite for bone repair applications

    Energy Technology Data Exchange (ETDEWEB)

    Eftekhari, Samin [Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); El Sawi, Ihab; Bagheri, Zahra Shaghayegh [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); Turcotte, Ginette [Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); Bougherara, Habiba, E-mail: habiba.bougherara@ryerson.ca [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada)

    2014-06-01

    The purpose of this research is to develop and characterize a novel biomimetic nanocomposite that closely mimics the properties of real bone such as morphology, composition and mechanical characteristics. This novel porous nanocomposite is composed of cotton-sourced cellulose microcrystals, hydroxyapatite nanoparticles and poly L-lactide acid. A unique combination of commonly used fabrication procedures has been developed including pre-treatment of particles using a coupling agent. The effect of various weight ratios of the reinforcing agents was evaluated to assess their influence on the chemical, thermal, and mechanical properties of the nanocomposites. The prepared nanocomposites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and compression testing. Our results indicated the presence of molecular interactions between all components leading to an increase of the crystallinity of the polymer from 50% to 80%. Compression test results revealed that increasing the weight ratio of microcrystalline cellulose/poly L-lactide acid and hydroxyapatite/poly L-lactide acid from 0.1 to 0.5 enhanced the compressive yield stress from 0.127 to 2.2 MPa and The Young's modulus from 6.6 to 38 MPa, respectively. It was found that the fabricated nanocomposites are comparable with the trabecular bone from compositional, structural, and mechanical point of view. - Highlights: • Fabrication of PLLA/HA/cellulose composites that mimic the spongeous bone • Homogenous dispersion of the reinforcing agents in the PLLA matrix was attained. • More efficient interface between the PLLA and the reinforcing agents was achieved. • Preliminary in vitro biocompatibility test showed the nontoxicity of the composite. • The crystallinity, the compressive strength and modulus were investigated.

  7. Study on application of zirconium dioxide for upgrading quality of pouring cups used in continuous steel casting technology

    International Nuclear Information System (INIS)

    This theme studies on technology of zirconium oxide powder stabilized by calcium and testing production of steel pouring cup made of the stabilized dioxide zirconium ceramic. As a product of the theme, the steel pouring cup has had the following main characteristics: heat resistance > 1700oC, density of 4.7 g/cm3, apparent sponge degree of 1.63%, compressibility of 3300 kg/cm2. The quality of the cup has been tested and highly evaluated during the actual production. (author)

  8. Membrane Made of Cellulose Acetate with Polyacrylic Acid Reinforced with Carbon Nanotubes and Its Applicability for Chromium Removal

    Directory of Open Access Journals (Sweden)

    J. A. Sánchez-Márquez

    2015-01-01

    Full Text Available Membranes made of carbon nanotubes and cellulose acetate with polyacrylic acid were designed in order to study their properties and their applicability for chromium removal. The membranes were prepared by phase inversion method using cellulose acetate and polyacrylic acid. Carbon nanotubes were added to the membrane during their process of synthesis in proportions of 1% by weight. The pores in the material are formed in layers, giving the effect of depth and forming a network. Both the carbon nanotubes and membranes were characterized by IR, Raman, and SEM spectroscopy. In addition, the concentration of acidic and basic sites and the surface charge in the materials were determined. The concentration of acid sites for oxidized nanotubes was 4.0 meq/g. The removal of Cr(VI was studied as a function of contact time and of initial concentration of Cr(VI. The removal of Cr(VI (~90% mainly occurs in a contact time from 32 to 64 h when the initial concentration of Cr(VI is 1 mg/L.

  9. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja S.;

    2012-01-01

    Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we...... not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid...

  10. Synthese de nanoparticules plasmoniques par laser femtoseconde en milieu liquide pour des applications biomedicales

    Science.gov (United States)

    Besner, Sebastien

    The femtosecond laser synthesis of plasmonic nanoparticles (Au, Ag, Cu, AuAg, AuCu) is described. The approach relies on the fs laser ablation of a target immersed in a liquid, followed by the laser-induced fragmentation and growth of nanoparticles in solution. This two-step methodology significantly enhances the production rate, the reproducibility and the size control of nanoparticles in comparison to the direct laser ablation based technique. For gold, the laser-induced growth of nanometric seeds initially formed by laser ablation in the presence of a stabilizing agent allows the synthesis of functionalized nanoparticles with sizes ranging from 3-76 nm and coefficients of variation (COV) varying between 15-30%. In comparison to the direct laser ablation, the size control is much simpler, as it uniquely depends on the gold to stabilizing agent molecular concentration ratio. The approach has been described for dextran and polyethylene glycol (PEG), but can be extended to all stabilizing agents and open new avenues in the formation of various novel bioconjugates. The fs laser ablation and fragmentation also allow the synthesis of stable and low dispersed Au nanoparticles in pure water. These nanoparticles are unique for sensing applications with high sensitivity based on surface enhanced Raman scattering (SERS), since they greatly reduce the noise associated with surface contaminants and byproducts found in solution. The formation of various nanospheres with predetermined size, shape and composition (AuxAg(1-x), AuxCu(1-x) ) is also reported by the use of a fs irradiation of a mixture of two pure metallic ix colloidal solutions in a very simple chemical environment, e.g. water and a stabilizing agent. From a chemical point of view, oxidation of silver nanoparticles is significantly reduced by the incorporation of a small amount of gold and is completely inhibited for a gold atomic fraction larger than 0.4-0.5. The bifunctional nature related to the partial

  11. The cellulose synthase companion proteins act non-redundantly with CELLULOSE SYNTHASE INTERACTING1/POM2 and CELLULOSE SYNTHASE 6

    OpenAIRE

    Endler, Anne; Schneider, Rene; Kesten, Christopher; Edwin R Lampugnani; Persson, Staffan

    2016-01-01

    ABSTRACT Cellulose is a cell wall constituent that is essential for plant growth and development, and an important raw material for a range of industrial applications. Cellulose is synthesized at the plasma membrane by massive cellulose synthase (CesA) complexes that track along cortical microtubules in elongating cells of Arabidopsis through the activity of the protein CELLULOSE SYNTHASE INTERACTING1 (CSI1). In a recent study we identified another family of proteins that also are associated ...

  12. Characterisation of microcrystalline cellulose from oil palm fibres for food applications.

    Science.gov (United States)

    Xiang, Loo Yu; P Mohammed, Mohd Afandi; Samsu Baharuddin, Azhari

    2016-09-01

    Microcrystalline cellulose (MCC) extracted from empty fruit bunches (EFB), stalk and spikelet were characterised through physicochemical and microstructure analyses. Raw stalk fibres yielded the highest cellulose content (42.43%), followed by EFB (32.33%) and spikelet (18.83%). Likewise, lowest lignin and residual oil content was reported in raw stalk fibres compared to EFB and spikelet. SEM revealed significant changes on fibres' surface morphology throughout the extraction process. FTIR analysis showed that main characteristic peaks of hemicellulose and lignin was absent on the extracted MCC. The crystallinity index for MCC extracted from EFB (82.5%), stalk (82.2%) and spikelet (86.5%) was comparable to commercial MCC (81.9%). Results suggested stalk fibres is more preferable for the production of MCC compared to EFB and spikelet. Further rheological studies showed viscoelastic behaviour with no significant differences between commercial and stalk-based MCC, while modelling work showed ability to simulate complex deformation of the MCC-hydrogel/food mixture during processing/handling stage. PMID:27185110

  13. Application of microcrystalline cellulose to fabricate ZnO with enhanced photocatalytic activity

    International Nuclear Information System (INIS)

    Highlights: • Microcrystalline cellulose was applied to fabricate ZnO. • Obtained ZnO nanocrystallites feature morphology of slice clusters and flowers. • Our ZnO exhibits excellent photocatalytic activity, superior to P25. • Re-used performance of our ZnO catalyst retains high even after 5 cycles. - Abstract: Microcrystalline cellulose (MCC), deriving from naturally renewable biomass resources, has been used to fabricate nanocrystalline ZnO materials via a facile hydrothermal method. XRD analysis results indicate that the obtained ZnO crystallite possess hexagonal wurtzite structure. Its morphology was measured by SEM, showing slice clusters and flowers. Comparatively, ZnO of irregular slices was prepared when no MCC was added in the synthetic route. ZnO synthesized with and without MCC behaves quite different photocatalytic activity. It is found that photocatalytic efficiency of ZnO prepared by 1 g MCC on degrading methylene blue reaches 98.3% under UV irradiation (power of 6 W). This is higher than the catalytic efficiency of both the ZnO prepared without MCC addition and of the commercial Degussa P25. Simultaneously, the as-prepared ZnO also exhibits excellent reusable ability. No obvious abatement is observed after the catalyst is re-used for 5 cycles. Taken together high photocatalytic and re-used efficiency, we anticipate that our controllable, environment-friendly and cost-effective approach can be applied to synthesize ZnO catalytic materials on a large scale

  14. Novel carboxymethyl cellulose based nanocomposite membrane: Synthesis, characterization and application in water treatment.

    Science.gov (United States)

    Saber-Samandari, Samaneh; Saber-Samandari, Saeed; Heydaripour, Samira; Abdouss, Majid

    2016-01-15

    Significant efforts have been made to develop composite membranes with high adsorption efficiencies for water treatment. In this study, a carboxymethyl cellulose-graft-poly(acrylic acid) membrane was synthesized in the presence of silica gel, which was used as an inorganic support. Then, different amounts of bentonite were introduced to the carboxymethyl cellulose (CMC) grafted networks as a multifunctional crosslinker, and nanocomposite membranes were prepared. The nanocomposite membranes were characterized using Fourier transform infrared spectroscopy, and scanning electron microscopy, which revealed their compositions and surface morphologies. The novel synthesized nanocomposite membranes were utilized as adsorbents for the removal of crystal violet (CV) and cadmium (Cd (II)) ions, which were selected as representatives of a dye and a heavy metal, respectively. We explored the effects of various parameters, such as time, pH, temperature, initial concentration of adsorbate solution and amount of adsorbent, on membrane adsorption capacity. Furthermore, the kinetic, adsorption isotherm models and thermodynamic were employed for the description of adsorption processes. The maximum adsorption capacities of membranes for CV and Cd (II) ions were found to be 546 and 781 mg g(-1), respectively. The adsorption of adsorbate ions by all types of nanocomposite membranes followed pseudo-second-order kinetic model and was best fit with the Freundlich adsorption isotherm. The results indicated that the synthesized nanocomposite membrane is an efficient adsorbent for the removal of cationic dye and metal contaminants from aqueous solution during water treatment. PMID:26560638

  15. Application of Vat Green 1 dye on gamma ray treated cellulosic fabric

    International Nuclear Information System (INIS)

    For the present study, Vat Green 1 dye has been selected for dyeing gamma irradiated cellulosic fabric. The dyeing variables such as dyeing temperature, dyeing time and dyeing pH were optimized. Concentrations of sodium hydrosulphite for reduction process and hydrogen peroxide for oxidation process were also optimized. After evaluation of dyed fabrics in a CIE Lab system using Spectraflash SF-650 it has been found that 6 kGy is the effective absorbed dose for improvement in dyeing behaviour of cellulosic fabric. Good colour strength has been obtained by dyeing optimal irradiated fabric (6 kGy, IC) at 75 °C for 1 h. by employing dyeing solution of pH 11. It has also been found that gamma ray treatment has reduced the necessary quantity of reducing (NaHSO3) and oxidizing agents (H2O2). The rating results after implementation of suggested standard methods of ISO for colourfastness showed that using irradiated textiles, the fastness to light, washing and rubbing has been significantly improved. - Highlights: • The optimal absorbed doses for surface modification of cotton are 6 kGy. • Irradiation has reduced the amount of chemicals needed. • Optimal dyeing conditions are 75 °C, 60 min and pH 11. • Optimal quantity of sodium hydrosulphite is 1.2 g and of H2O2 is 1.2 mL. • At optimal conditions, colour strength and fastness properties are enhanced

  16. Pigment-cellulose nanofibril composite and its application as a separator-substrate in printed supercapacitors

    Science.gov (United States)

    Torvinen, Katariina; Lehtimäki, Suvi; Keränen, Janne T.; Sievänen, Jenni; Vartiainen, Jari; Hellén, Erkki; Lupo, Donald; Tuukkanen, Sampo

    2015-11-01

    Pigment-cellulose nanofibril (PCN) composites were manufactured in a pilot line and used as a separator-substrate in printed graphene and carbon nanotube supercapacitors. The composites consisted typically of 80% pigment and 20% cellulose nanofibrils (CNF). This composition makes them a cost-effective alternative as a substrate for printed electronics at high temperatures that only very special plastic films can nowadays stand. The properties of these substrates can be varied within a relatively large range by the selection of raw materials and their relative proportions. A semi-industrial scale pilot line was successfully used to produce smooth, flexible, and nanoporous composites, and their performance was tested in a double functional separator-substrate element in supercapacitors. The nanostructural carbon films printed on the composite worked simultaneously as high surface area active electrodes and current collectors. Low-cost supercapacitors made from environmentally friendly materials have significant potential for use in flexible, wearable, and disposable low-end products. [Figure not available: see fulltext.

  17. Représentation des connaissances pour les problèmes de conception. Application à un système à base de connaissances pour la conception de réseaux informatiques : NEST.

    OpenAIRE

    Jouve, Christine

    1992-01-01

    Réalisée dans le cadre d'un projet Esprit Il, cette thèse a eu pour objectif principal la réalisation d'un système à base de connaissances pour la conception de réseaux. A travers le développement de ce système appelé NEST (pour Network design Expert SysTem), deux principaux ax~s de recherche ont été entrepris : la modélisation d'une activité de conception pour laquelle 1 'intelligence artificielle a relativement peu de théories et la configuration de réseaux locaux pour laquelle peu de systè...

  18. Adsorption and desorption of cellulose derivatives.

    NARCIS (Netherlands)

    Hoogendam, C.W.

    1998-01-01

    Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.In chapter 1 of this thesis we discuss some appl

  19. Bioengineering cellulose-hemicellulose networks in plants

    NARCIS (Netherlands)

    Obembe, O.

    2006-01-01

    The interactions between cellulose and hemicellulose in the cell walls are important in the industrial application of the cellulose (natural) fibres. We strive to modify these interactions (i) by interfering with cellulose biosynthesis and (ii) by direct interference of the

  20. Degradation of cellulose nitrate with fast neutrons and gamma rays and their application in radiation dosimetry

    International Nuclear Information System (INIS)

    Fast and moderated neutrons emitted from 252Cf as well as low doses of gamma rays from 60Co, produce damaging effects in cellulose nitrate which can be determined viscometrically by calculating the average molecular weight at different doses. Samples were exposed to different doses of gamma rays (1x10-4 to 1 Gy) and fission neutron fluences (105-1011 n/cm2) in free space and on a paraffin phantom. The effect of phantom thickness and phantom-to-detector distance on the detector readout have been investigated. The results revealed that the predominant bulk effects of radiation on CN is accelerated degradation by random chain scission. Empirical formulae have been given to calculate the absorbed doses of gamma rays and fast neutrons from the measured average molecular weight of the irradiated samples. (orig.)

  1. Application of ultra cellulose fiber for the enhancement of the durability

    Directory of Open Access Journals (Sweden)

    Saaid I. Zaki

    2015-08-01

    Full Text Available Ultra Cellulose Fibers are hydrophilic fibers which can hold most of their weight water when it is mixed into concrete, after concrete is hardened, these fibers will slowly release this water to unhydrated cement during the critical early phases of curing which assist in more complete hydration, this internal self curing action results in more completely hydrated cement which contributes to more strength development and more control of internal microcracking, particularly when normal curing is not adequate. Also, these fibers can be used easily in ready mixed concrete batch plants and in hot weather environments. The results indicated clear improvements in both the shrinkage and compressive strength of all cement paste mixes contained these fibers in comparison with control ones in both normal and aggressive curing conditions.

  2. Modification of a cellulose derived for your application on enzyme immobilization

    International Nuclear Information System (INIS)

    The chemical modification of (acrylamidomethyl) cellulose acetate propionate (AMCAP) was done through the technique of grafting via radical using acrylic acid as modifier, with the objective to make the polymer more hydrophilic. The structural characterization of AMCAP and modified AMCAP-H2O2 was analysed by using the technique of 13C-nuclear magnetic resonance (NMR-13C). By the techniques differential scanning calorimetry analysis (DSC) and thermogravimetric analysis (TGA), the thermal properties was characterized and the hydrophobic / hydrophilic character was determined by measurements of the contact angle. The results show that occurred the change intended with the introduction of acrylic acid in the side chain of the polymer, increasing the hydrophilic character on the AMCAP. (author)

  3. Chitosan-cellulose composite materials: Preparation, Characterization and application for removal of microcystin

    International Nuclear Information System (INIS)

    Highlights: •A novel and recyclable synthetic method using an ionic liquid, a Green Solvent. •Ecocomposite materials were synthesized from cellulose (CEL) and chitosan (CS). •Adding CEL into CS substantially increases tensile strength of the composite. •The composite is much better adsorbent for cyanotoxins than other materials. •The composite can be reused because adsorbed microcystin can be desorbed. -- Abstract: We developed a simple and one-step method to prepare biocompatible composites from cellulose (CEL) and chitosan (CS). [BMIm+Cl−], an ionic liquid (IL), was used as a green solvent to dissolve and prepare the [CEL + CS] composites. Since majority (>88%) of IL used was recovered for reuse by distilling the aqueous washings of [CEL + CS], the method is recyclable. XRD, FTIR, NIR, 13C CP-MAS-NMR and SEM were used to monitor the dissolution and to characterize the composites. The composite was found to have combined advantages of their components: superior mechanical strength (from CEL) and excellent adsorption capability for microcystin-LR, a deadly toxin produced by cyanobacteria (from CS). Specifically, the mechanical strength of the composites increased with CEL loading; e.g., up to 5× increase in tensile strength was achieved by adding 80% of CEL into CS. Kinetic results of adsorption confirm that unique properties of CS remain intact in the composite, i.e., it is not only a very good adsorbent for microcystin but also is better than all other available adsorbents. For example, it can adsorb 4× times more microcystin than the best reported adsorbent. Importantly, the microcystin adsorbed can be quantitatively desorbed to enable the composite to be reused with similar adsorption efficiency

  4. Perception multisensorielle pour la localisation d'un robot mobile en environnement extérieur, application aux véhicules routiers

    OpenAIRE

    Laneurit, Jean

    2006-01-01

    This thesis report deals with precise and uncorrupted localisation of mobile robots within a road environment associated to a precise numerical map. Le sujet traité dans cette thèse concerne la localisation précise et intègre de robots mobiles ( de véhicules routiers en l'occurence) dans un environnement routier cartographié. Pour ceci, nous proposons une approche multisensorielle hybridant les capteurs classiquement utilisés dans ce genre d'application (un GPS naturel, un odomètre et un g...

  5. Application of Box-Behnken Design in Optimization of Glucose Production from Oil Palm Empty Fruit Bunch Cellulose

    OpenAIRE

    Satriani Aga Pasma; Rusli Daik; Mohamad Yusof Maskat; Osman Hassan

    2013-01-01

    Oil palm empty fruit bunch fiber (OPEFB) is a lignocellulosic waste from palm oil mills. It contains mainly cellulose from which glucose can be derived to serve as raw materials for valuable chemicals such as succinic acid. A three-level Box-Behnken design combined with the canonical and ridge analysis was employed to optimize the process parameters for glucose production from OPEFB cellulose using enzymatic hydrolysis. Organosolv pretreatment was used to extract cellulose from OPEFB using et...

  6. Small-animal SPECT/CT and nanofibrillar cellulose hydrogels: a preclinical evaluation of a potential novel biomaterial application

    OpenAIRE

    Laurén, Patrick

    2013-01-01

    Cellulose has already been used as an industrial raw material for over a century. However, during recent years the nanostructural features of the naturally occurring biopolymer have been fully investigated and characterized through different processing methods as nanofibrillar cellulose (NFC). This has led to a rapid development of novel cellulose based nanoscale materials and advancements in the field of composite materials. NFC offers interesting specific properties that differ from man...

  7. The cellulose resource matrix.

    Science.gov (United States)

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  8. Principes et application de la digestion anaérobie pour la production d'énergie

    OpenAIRE

    Bernet, Nicolas

    2015-01-01

    La digestion anaérobie est un processus naturel par lequel la matière organique est transformée en un biogaz qui contient environ 2/3 de méthane et 1/3 de dioxyde de carbone. Elle résulte de l’activité d’un écosystème microbien anaérobie complexe. Le biogaz est une source d’énergie qui peut être utilisée directement en remplacement du gaz naturel, pour produire de la chaleur et de l’électricité par cogénération ou encore comme carburant pour véhicules. Ainsi, la domestication par l’homme de c...

  9. Bacterial cellulose composites: Synthetic strategies and multiple applications in bio-medical and electro-conductive fields.

    Science.gov (United States)

    Ul-Islam, Mazhar; Khan, Shaukat; Ullah, Muhammad Wajid; Park, Joong Kon

    2015-12-01

    Bacterial cellulose (BC), owing to its pure nature and impressive physicochemical properties, including high mechanical strength, crystallinity, porous fibrous structure, and liquid absorbing capabilities, has emerged as an advanced biomaterial. To match the market demand and economic values, BC has been produced through a number of synthetic routes, leading to slightly different structural features and physical appearance. Chemical nature, porous geometry, and 3D fibrous structure of BC make it an ideal material for composites synthesis that successfully overcome certain deficiencies of pure BC. In this review, we have focused various strategies developed for synthesizing BC and BC composites. Reinforcement materials including nanoparticles and polymers have enhanced the antimicrobial, conducting, magnetic, biocompatible, and mechanical properties of BC. Both pure BC and its composites have shown impressive applications in medical fields and in the development of optoelectronic devices. Herein, we have given a special attention to discuss its applications in the medical and electronic fields. In conclusion, BC and BC composites have realistic potential to be used in future development of medical devices, artificial organs and electronic and conducting materials. The contents discussed herein will provide an eye-catching theme to the researchers concerned with practical applications of BC and BC composites. PMID:26395011

  10. Biotemplated preparation of CdS nanoparticles/bacterial cellulose hybrid nanofibers for photocatalysis application

    International Nuclear Information System (INIS)

    In this work, we describe a novel facile and effective strategy to prepare micrometer-long hybrid nanofibers by deposition of CdS nanoparticles onto the substrate of hydrated bacterial cellulose nanofibers (BCF). Hexagonal phase CdS nanocrystals were achieved via a simple hydrothermal reaction between CdCl2 and thiourea at relatively low temperature. The prepared pristine BCF and the CdS/BCF hybrid nanofibers were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-vis absorption spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results reveal that the CdS nanoparticles were homogeneously deposited on the BCF surface and stabilized via coordination effect. The CdS/BCF hybrid nanofibers demonstrated high-efficiency photocatalysis with 82% methyl orange (MO) degradation after 90 min irradiation and good recyclability. The results indicate that the CdS/BCF hybrid nanofibers are promising candidate as robust visible light responsive photocatalysts.

  11. Biotemplated preparation of CdS nanoparticles/bacterial cellulose hybrid nanofibers for photocatalysis application

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jiazhi; Yu, Junwei [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China); Fan, Jun [School of Environment, Nanjing University, Nanjing 210093 (China); Sun, Dongping, E-mail: dongpingsun@163.com [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China); Tang, Weihua, E-mail: whtang@mail.njust.edu.cn [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China); Yang, Xuejie [Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology, Nanjing 210094 (China)

    2011-05-15

    In this work, we describe a novel facile and effective strategy to prepare micrometer-long hybrid nanofibers by deposition of CdS nanoparticles onto the substrate of hydrated bacterial cellulose nanofibers (BCF). Hexagonal phase CdS nanocrystals were achieved via a simple hydrothermal reaction between CdCl{sub 2} and thiourea at relatively low temperature. The prepared pristine BCF and the CdS/BCF hybrid nanofibers were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), UV-vis absorption spectroscopy (UV-vis), and X-ray photoelectron spectroscopy (XPS). The results reveal that the CdS nanoparticles were homogeneously deposited on the BCF surface and stabilized via coordination effect. The CdS/BCF hybrid nanofibers demonstrated high-efficiency photocatalysis with 82% methyl orange (MO) degradation after 90 min irradiation and good recyclability. The results indicate that the CdS/BCF hybrid nanofibers are promising candidate as robust visible light responsive photocatalysts.

  12. Biomimetic synthesis of hydroxyapatite/bacterial cellulose nanocomposites for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Y.Z. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)]. E-mail: yzwantju@yahoo.com; Huang, Y. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Yuan, C.D. [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Raman, S. [Department of Community Health and Epidemiology, Queen' s University, Kingston, Ontario, Canada K7L 3N6 (Canada); Zhu, Y. [School of Chemical Engineering, Tianjin University, Tianjin 300072 (China); Jiang, H.J. [Wendeng Hospital of Orthopaedics, Shandong 264400 (China); He, F. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Gao, C. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2007-05-16

    Hydroxyapatite (HAp) and bacterial cellulose (BC) are both excellent materials for use in biomaterial areas. The former has outstanding osteoconductivity and bioactivity and the latter is a high-strength nano-fibrous and extensively used biomaterial. In this work, the HAp/BC nanocomposites with a 3-dimensional (3-D) network were synthesized via a biological route by soaking both phosphorylated and unphosphorylated BCs in 1.5 simulated body fluid (SBF). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were employed to characterize the HAp/BC nanocomposites. SEM observations demonstrated that HAp crystals were uniformly formed on the phosphorylated BC fibers after soaking in 1.5 SBF whereas little HAp was observed on individual unphosphorylated BC fibers. Our experimental results suggested that the unphosphorylated BC did not induce HAp growth and that phosphorylation effectively triggered HAp formation on BC. Mechanisms were proposed for the explanation of the experimental observations. XRD and FTIR results revealed that the HAp crystals formed on the phosphorylated BC fibers were carbonate-containing with nano-sized crystallites and crystallinities less than 1%. These structural features were close to those of biological apatites.

  13. Cellulose nanocrystals mediated assembly of graphene in rubber composites for chemical sensing applications.

    Science.gov (United States)

    Cao, Jie; Zhang, Xinxing; Wu, Xiaodong; Wang, Shuman; Lu, Canhui

    2016-04-20

    In this study, we report a green assembled approach to prepare natural rubber (NR) composites with 3D interconnected graphene-based conductive networks. Taking advantage of the water-dispersity and amphiphilicity of cellulose nanocrystals (CNC), well suspended graphene@CNC aqueous colloids could be prepared by the CNC-mediated reduction of graphene oxide. When homogenized with NR latex under ultrasonication and subsequently co-coagulation, the graphene@CNC nanohybrids selectively located in the interstitial space between the NR latex microspheres and constructed an ordered 3D conductive structure. This unique 3D conductive network endowed the NR composites with remarkably enhanced electric conductivity (the percolation threshold is twofold lower than that of the conventional NR/graphene composites), mechanical properties and more importantly resistivity response to organic liquids. Our strategy offered a novel, simple and eco-friendly route for the fabrication of liquid sensors capable of sensing and discriminating various solvent leakage in chemical industry as well as environmental monitoring. PMID:26876831

  14. Modified Cellulosic Materials with Antioxidant and AntimicrobialProperties for Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Anamaria Irimia

    2015-04-01

    Full Text Available Elaboration of a two steps physico-chemical process to obtain antimicrobial and antioxidant materials. A two-step process was used for modification of a cellulose/chitin mix fiber (CCfirst an enzymatic activation with a commercial cellulase enzyme was applied and then a coupling reaction with phenolic antioxidants such as p-hydroxybenzoic acid (HBA,gallicacid(GA and eugenol (Eu was carried out to evolve antimicrobial and antioxidant properties. Both the enzyme activated and the subsequently modified with antioxidant moieties samples were characterized by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy scanning electron microscopy and thermogravimetry. Furthermore, the antioxidant and antibacterial capacities were tested. All obtained results confirm the morphological and structural changes on the fiber surface after the twostep procedure of modification. Based on the XPS results, the modification degrees of the superficial layers of the fibers varied between 35 and 43%. Both the antimicrobial and radical scavenging activities were up to 100% and the order of the antioxidant activity can be written as: CC/Eu > CC/ GA > CC/HBA. Materials with these functionalities can be widely applied in the dermo-cosmetic field to protect the skin from oxidative stress, as transdermal patches which could be effectively used as a material in wound dressings.

  15. Biomimetic synthesis of hydroxyapatite/bacterial cellulose nanocomposites for biomedical applications

    International Nuclear Information System (INIS)

    Hydroxyapatite (HAp) and bacterial cellulose (BC) are both excellent materials for use in biomaterial areas. The former has outstanding osteoconductivity and bioactivity and the latter is a high-strength nano-fibrous and extensively used biomaterial. In this work, the HAp/BC nanocomposites with a 3-dimensional (3-D) network were synthesized via a biological route by soaking both phosphorylated and unphosphorylated BCs in 1.5 simulated body fluid (SBF). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were employed to characterize the HAp/BC nanocomposites. SEM observations demonstrated that HAp crystals were uniformly formed on the phosphorylated BC fibers after soaking in 1.5 SBF whereas little HAp was observed on individual unphosphorylated BC fibers. Our experimental results suggested that the unphosphorylated BC did not induce HAp growth and that phosphorylation effectively triggered HAp formation on BC. Mechanisms were proposed for the explanation of the experimental observations. XRD and FTIR results revealed that the HAp crystals formed on the phosphorylated BC fibers were carbonate-containing with nano-sized crystallites and crystallinities less than 1%. These structural features were close to those of biological apatites

  16. TEMPO-oxidized cellulose nanofibers

    Science.gov (United States)

    Isogai, Akira; Saito, Tsuguyuki; Fukuzumi, Hayaka

    2011-01-01

    Native wood celluloses can be converted to individual nanofibers 3-4 nm wide that are at least several microns in length, i.e. with aspect ratios >100, by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and successive mild disintegration in water. Preparation methods and fundamental characteristics of TEMPO-oxidized cellulose nanofibers (TOCN) are reviewed in this paper. Significant amounts of C6 carboxylate groups are selectively formed on each cellulose microfibril surface by TEMPO-mediated oxidation without any changes to the original crystallinity (~74%) or crystal width of wood celluloses. Electrostatic repulsion and/or osmotic effects working between anionically-charged cellulose microfibrils, the ζ-potentials of which are approximately -75 mV in water, cause the formation of completely individualized TOCN dispersed in water by gentle mechanical disintegration treatment of TEMPO-oxidized wood cellulose fibers. Self-standing TOCN films are transparent and flexible, with high tensile strengths of 200-300 MPa and elastic moduli of 6-7 GPa. Moreover, TOCN-coated poly(lactic acid) films have extremely low oxygen permeability. The new cellulose-based nanofibers formed by size reduction process of native cellulose fibers by TEMPO-mediated oxidation have potential application as environmentally friendly and new bio-based nanomaterials in high-tech fields.

  17. Etude du potentiel des sous-produits vinicoles pour des applications à haute valeur ajoutée

    OpenAIRE

    Berchem, Thomas; Jacquet, Nicolas; Richel, Aurore

    2016-01-01

    d’une population mondiale en expansion constante, il est primordial de trouver des voies de production plus durables pour les produits de consommation courante. La chimie biobasée et le bioraffinage constituent une alternative à laquelle il convient de porter une grande attention. La très grande quantité de biomasse constituée par les déchets verts produits à l’échelle planétaire représente une ressource énergétique et chimique très peu exploitée jusqu’à présent. Les sous-produits vini...

  18. Research on the Application of Bacterial Cellulose in Papermaking%细菌纤维素在造纸工业中的应用

    Institute of Scientific and Technical Information of China (English)

    汤卫华; 贾士儒; 王芃; 殷海松

    2013-01-01

    细菌纤维素是由细菌产生的纯度很高的纳米级纤维素,具有结晶度和纯度高、机械强度大和生物相容性好等特点.在植物纤维中添加细菌纤维素,可改善纸张性能.细菌纤维素可用于制备特种纸和“电子纸”.%Bacterial cellulose (BC) is secreted by Acetobacter xylinum. Compared with plant fiber, it possesses an array of unique properties , including high crystallinity, high water content, biocompatibility, high mechanical strength and an ultra-fine fiber network. Bacterial cellulose can be used for making unusually strong paper, because it consists of extremely small clusters of cellulose microbrils, this property greatly upgrades the strength and durability of the paper when it is added to the paper. There are some issues in large-scale application of bacterial cellulose to be solved, such as the high cost, low yield, mechanical stability and so on.

  19. In situ synthesis of robust conductive cellulose/polypyrrole composite aerogels and their potential application in nerve regeneration.

    Science.gov (United States)

    Shi, Zhuqun; Gao, Huichang; Feng, Jiao; Ding, Beibei; Cao, Xiaodong; Kuga, Shigenori; Wang, Yingjun; Zhang, Lina; Cai, Jie

    2014-05-19

    Nanostructured conductive polymers can offer analogous environments for extracellular matrix and induce cellular responses by electric stimulation, however, such materials often lack mechanical strength and tend to collapse under small stresses. We prepared electrically conductive nanoporous materials by coating nanoporous cellulose gels (NCG) with polypyrrole (PPy) nanoparticles, which were synthesized in situ from pyrrole monomers supplied as vapor. The resulting NCG/PPy composite hydrogels were converted to aerogels by drying with supercritical CO2, giving a density of 0.41-0.53 g cm(-3), nitrogen adsorption surface areas of 264-303 m(2) g(-1), and high mechanical strength. The NCG/PPy composite hydrogels exhibited an electrical conductivity of up to 0.08 S cm(-1). In vitro studies showed that the incorporation of PPy into an NCG enhances the adhesion and proliferation of PC12 cells. Electrical stimulation demonstrated that PC12 cells attached and extended longer neurites when cultured on NCG/PPy composite gels with DBSA dopant. These materials are promising candidates for applications in nerve regeneration, carbon capture, catalyst supports, and many others. PMID:24711342

  20. Biopolymer Materials Based Carboxymethyl Cellulose as a Proton Conducting Biopolymer Electrolyte for Application in Rechargeable Proton Battery

    International Nuclear Information System (INIS)

    This paper presents the discovery on proton conducting biopolymer electrolyte (BPE) by incorporating various NH4Br composition (wt%) with biopolymer materials carboxymethyl cellulose (CMC) which has been prepared via solution casting method. The biopolymer–salt complex formation has been analyzed through Fourier Transform Infrared (FTIR) spectroscopy, Thermo Gravimetric Analysis (TGA), impedance and transference number measurement (TNM). The highest ionic conductivity at ambient temperature is 1.12 × 10−4 S cm−1 for sample containing 25 wt% NH4Br. It has been shown that the conducting element in this work are predominantly due to proton (H+) which was confirmed via FTIR and TNM analysis. Rechargeable proton conducting BPE battery have been fabricated with the configuration of Zn + ZnSO4.7H2O/BPE/MnO2 and produced a maximum open circuit potential (OCP) of 1.36 V at ambient temperature and showed good rechargeability. This work implies that the possible practical application of the present electrolytes as a new invention in the fabrication of electrochemical devices

  1. Application of Box-Behnken Design in Optimization of Glucose Production from Oil Palm Empty Fruit Bunch Cellulose

    Directory of Open Access Journals (Sweden)

    Satriani Aga Pasma

    2013-01-01

    Full Text Available Oil palm empty fruit bunch fiber (OPEFB is a lignocellulosic waste from palm oil mills. It contains mainly cellulose from which glucose can be derived to serve as raw materials for valuable chemicals such as succinic acid. A three-level Box-Behnken design combined with the canonical and ridge analysis was employed to optimize the process parameters for glucose production from OPEFB cellulose using enzymatic hydrolysis. Organosolv pretreatment was used to extract cellulose from OPEFB using ethanol and water as the solvents. The extracted cellulose was characterized by thermogravimetric analysis, FTIR spectroscopy, and field emission scanning electron microscopy. Hydrolysis parameters including amount of enzyme, amount of cellulose, and reaction time were investigated. The experimental results were fitted with a second-order polynomial equation by a multiple regression analysis and found that more than 97% of the variations could be predicted by the models. Using the ridge analysis, the optimal conditions reaction time found for the production of glucose was 76 hours and 30 min, whereas the optimum amount of enzyme and cellulose was 0.5 mL and 0.9 g, respectively. Under these optimal conditions, the corresponding response value predicted for glucose concentration was 169.34 g/L, which was confirmed by validation experiments.

  2. Dimensionnement multi-objectif d'une association batterie – supercondensateur pour une application photovoltaïque

    OpenAIRE

    Dulout, Jérémy; Jammes, Bruno; Séguier, Lionel; Alonso, Corinne

    2016-01-01

    National audience Les énergies renouvelables comme le solaire photovoltaïque (PV) et l'éolien présentent une production intermittente et difficile à prédire précisément. Le stockage de l'énergie permet, a priori, d'assurer à chaque instant l'équilibre entre production et demande, condition nécessaire au bon fonctionnement de tout réseau électrique. Cependant, bien que les éléments de stockage électrochimique (ESE) soient adaptés pour remplir ce rôle, leur coût étant important, il est néces...

  3. Application de la classification à vecteurs de support pour l'estimation de quantiles multidimensionnels extrêmes

    OpenAIRE

    Piera-Martinez, Miguel; Vazquez, Emmanuel; Fleury, Gilles; Walter, Eric

    2006-01-01

    Estimer une probabilité de défaillance d'un système entrée-sortie à partir d'observations ponctuelles de celui-ci est un problème important pour le monde industriel. Une approche possible consiste à modéliser le système comme la réalisation d'un processus aléatoire et de s'intéresser au volume d'excursion de ce processus. Soit $\\xi$ un processus aléatoire gaussien et $\\abs{A_u(\\xi)}$ le volume de l'ensemble d'excursion de $\\xi$ au dessus d'un seuil $u$ sous une mesure de probabilité $\\mu$. L'...

  4. Repérage et typage d'expressions temporelles pour l'annotation sémantique automatique de pages Web - Application au e-tourisme

    OpenAIRE

    Weiser, Stéphanie

    2010-01-01

    Cette thèse présente Adetoa, système dédié au repérage et à l'annotation sémantique automatique d'expressions temporelles dans des pages Web pour une application de e-tourisme. Une étude linguistique détaillée a permis de mettre en avant les caractéristiques et la complexité de l'expression de la temporalité dans les pages Web touristiques. Une étude sémiotique de ce type de pages a montré que les données y étaient organisées de manière fort variée, ne présentant aucune régularité, ce qui ren...

  5. Outillage pour la modélisation, la vérification et la génération d'applications temporisées et embarquées

    OpenAIRE

    Hladik, Pierre-Emmanuel; Dal Zilio, Silvano; Pasquier, Olivier; Pillement, Sébastien; Berthomieu, Bernard

    2016-01-01

    Cet article présente un travail en cours pour mettre en place une chaîne d'outils dédiée à la conception, la vérification et l'exécution de systèmes embarqués temps réel. Ce travail se base sur la méthode MCSE et les modèles qu'elle préconise pour la description d'applications. Une traduction du modèle dans le langage formel Fiacre est appliquée pour ensuite vérifier le système à l'aide du model-checker Tina. Afin de faciliter cette analyse et la génération d'un exécutif, la notion de Logical...

  6. Application of Flumethrin Pour-On on Reservoir Dogs and Its Efficacy against Sand Flies in Endemic Focus of Visceral Leishmaniasis, Meshkinshahr, Iran

    Directory of Open Access Journals (Sweden)

    MohammadReza Jalilnavaz

    2015-10-01

    Full Text Available Background: Visceral leishmaniasis (VL is one of the most important parasitic zoonotic diseases in the world. Do­mestic dogs are the main domestic reservoirs of VL in endemic foci of Iran. Various methods, including vaccination, treatment of dogs, detection and removal of infected dogs have different results around the world. General policy on control of canine visceral leishmaniasis is protection of them from sand fly bites. The aim of this study was evalua­tion of pour-on application of flumethrin on dogs against blood-feeding and mortality of field-caught sand flies.Methods: Once every 20 days from May untill September 2013, the treated and control dogs were exposed with field caught sandflies for 2 hours under bed net traps. After the exposure time, both alive and dead sand flies were trans­ferred in netted cups to the laboratory. The mortality rate of them was assessed after 24 hours. The blood-fed or un­fed conditions were determined 2 hours after exposure to the dogs under stereomicroscope.Results: The blood feeding index was varied from 12.0 to 25.0 % and 53.0 to 58.0 % for treated and control dogs respectively (P< 0.0001. The blood feeding inhibition was 75.0–87.0 % and 41.0–46.0 % for the control and treated dogs (P< 0.0001, respectively.The total mortality rate was 94.0–100 % and 19.0–58.0 % respectively for the treated and control groups (P< 0.001.Conclustion: Application of pour-on flumethrin on dogs caused 90–100 % mortality until 2.5 month and inhibited the blood-feeding of sand flies. 

  7. Research Progress on Fermentation Technology and Application of the Bacterial Cellulose%细菌纤维素发酵工艺与应用研究进展

    Institute of Scientific and Technical Information of China (English)

    陆胜民; 贾静静; 杨颖

    2011-01-01

    Bacterial cellulose, produced by some species of bacteria, has excellent properties including high mechanical strength, good water retention ability, and high crystallinity, which is applied widely to industries such as food industry.This paper summarized the structure, techno1ogy of fermentation and the application of bacterial cellulose in food industry.%由部分细菌所产生的纤维素称细菌纤维素,具有机械强度高、吸水性能好、纯度高、结晶度高等优良特性,广泛应用于食品工业等领域.本文对细菌纤维素的结构特性、发酵工艺研究及应用作了综述.

  8. Preparation of Cellulosic Membrane Containing Pyrrolidone Moiety Via Radiation Induced Grafting and its Application in Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    A. S. Aly

    2005-01-01

    Full Text Available Radiation induced grafting of vinyl pyrrolidone onto cellulose wood pulp was carried out in heterogeneous and homogenous media using gamma radiation. Cellulose wood pulp was used in different forms; a in a homogenous solution by dissolving the wood pulp in N,N- dimethylacetamide/Lithium chloride (DMAc/LiCl mixture , b in a membrane form, by precipitating the cellulose solution in water and c in a powder form. Factors affecting on the grafting such as radiation dose, monomer concentration, precipitator concentration and thickness of the membrane have been studied. The result showed that at the same dose, the grafting yield was higher with cellulose in soluble form than in the membrane form, whereas cellulose in powder exhibited the lowest graft yield. The grafted membrane was characterized by IR, TGA and SEM. The ability of the grafted membrane to remove dyes (acid and basic dye, heavy metal ions (Co 2+ , Ni 2+ and Cu 2+ and phenols from wastewater was also reported.

  9. Water dispersible microbicidal cellulose acetate phthalate film

    Directory of Open Access Journals (Sweden)

    Li Yun-Yao

    2003-11-01

    Full Text Available Abstract Background Cellulose acetate phthalate (CAP has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1, herpesviruses (HSV and other sexually transmitted disease (STD pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS. The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. Methods CAP and hydroxypropyl cellulose (HPC were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. Results The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable, and casting from organic solvent mixtures containing ≈50 to ≈65% ethanol (EtOH. The films are ≈100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. Conclusions Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into

  10. Application and Mechanism Study of NMMO Technology-based Natural Cellulose Membrane%NMMO工艺天然纤维素膜的应用及机理研究

    Institute of Scientific and Technical Information of China (English)

    李冬娜; 马晓军

    2013-01-01

    The preparation method and research progress of NMMO technology-based cellulose membrane at home and abroad are discussed, the application of NMMO technology-based cellulose membrane in different fields is introduced, the dissolution mechanism and film-forming mechanism of cellulose membrane are analyzed, and the application prospect of NMMO technology-based cellulose membrane is pointed out.%  论述了NMMO工艺纤维素膜的制备方法及在国内外的研究进展,介绍了NMMO工艺纤维素膜在不同领域的应用现状,分析了纤维素膜的溶解机理及成膜机理,指出了NMMO工艺纤维素膜的应用前景。

  11. Cellulose Synthases and Synthesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Anne Endler; Staffan Persson

    2011-01-01

    Plant cell walls are complex structures composed of high-molecular-weight polysaccharides,proteins,and lignins. Among the wall polysaccharides,cellulose,a hydrogen-bonded β-1,4-linked glucan microfibril,is the main load-bearing wall component and a key precursor for industrial applications. Cellulose is synthesized by large multi-meric cellulose synthase (CesA) complexes,tracking along cortical microtubules at the plasma membrane. The only known components of these complexes are the cellulose synthase proteins. Recent studies have identified tentative interaction partners for the CesAs and shown that the migratory patterns of the CesA complexes depend on phosphorylation status. These advances may become good platforms for expanding our knowledge about cellulose synthesis in the near future. In addition,our current understanding of cellulose chain polymerization in the context of the CesA complex is discussed.

  12. Effect of ionizing radiation on starch and cellulose

    International Nuclear Information System (INIS)

    The investigation is reported of the effects of ionizing radiation both on macromolecular systems generally and on polysaccharides, starch and cellulose. Attention is focused on changes in the physical and physico-chemical properties of starch and cellulose, such as starch swelling, gelation, viscosity, solubility, reaction with iodine, UV, IR and ESR spectra, chemical changes resulting from radiolysis and from the effect of amylases on irradiated starch, changes in cellulose fibre strength, water absorption, stain affinity, and also the degradation of cellulose by radiation and the effect of cellulases on irradiated cellulose. Practical applications of the findings concerning cellulose degradation are discussed. (author)

  13. A thermodynamic investigation of the cellulose allomorphs: Cellulose(am), cellulose Iβ(cr), cellulose II(cr), and cellulose III(cr)

    International Nuclear Information System (INIS)

    enthalpies of reactionΔrHw∘∗, the standard massic entropies of reaction ΔrSw∘∗, the standard massic Gibbs free energies of reaction ΔrGw∘∗, and the standard massic heat capacity ΔrCp,w∘, for the interconversion reactions of the pure (CI = 100) cellulose allomorphs, i.e., cellulose(am), cellulose I(cr), cellulose II(cr), and cellulose II(cr), at the temperature T = 298.15 K, the pressure p∘ = 0.1 MPa, and wH2O = 0.073. The “∗” denotes that the thermodynamic property pertains to pure cellulose allomorphs. Values of standard massic enthalpy differences Δ0THw∘, standard massic entropy differences Δ0TSw∘, and the standard massic thermal function Φw∘=Δ0TSw∘-Δ0THw∘/T were calculated from the measured heat capacities for the cellulose samples and for the pure cellulose allomorphs. The extensive literature pertinent to the thermodynamic properties of cellulose has been summarized and, in many cases, property values have been calculated or recalculated from previously reported data. The thermodynamic property data show that cellulose(am) is the least stable of the cellulose allomorphs considered in this study. However, due to the uncertainties in the measured property values, it is not possible to use these values to order the relative stabilities of the cellulose (I, II, and III) crystalline allomorphs with a reasonable degree of certainty. Nevertheless, based on chemical reactivity information, the qualitative order of stability for these three allomorphs is cellulose III(cr) > cellulose II(cr) > cellulose Iβ(cr) at T = 298.15 K. However, as evidenced by the fact that cellulose I(cr) can be reformed by the application of heat and water to a sample of cellulose III(cr), the differences in the stabilities of these three allomorphs appear to be small and may be temperature dependent. Standard thermodynamic formation properties as well as property values for the conversion reactions of the cellulose allomorphs to α-D-glucose(cr) have been

  14. Application of gold-198 in investigation of technological processes in cellulose and paper industry and in production of combined forage

    International Nuclear Information System (INIS)

    To label cellulose fibers and sawdust in investigation of acting installations for production of cellulose and semicellulose, gold-198 was used. The aim of investigation was to determine time of material's transfer in the cellulose production shop from the boiler to the outlet from washer and in the semicellulose production shop from the feeding bunker to refiners. Stable labelling of the cellulose fibers and sawdust has been gained, which permitted successfully to perform investigations of two installations in spite of high temperature and pressure and aggressive medium. Gold-198 is also a good indicator in investigations of technological lines of feed mills. After labelling of one of the main components of fodder mixture, it is introduced into mixer in the proportion used in the production for mixing. It is possible to trace process of mixing either by means of continious registering of by means of sampling. As a result of investigations, optimal time of mixing, segregation processes influence of the factory transport and intershop idle stand on the homogenity of product for factories with different equipment, can be determined

  15. ARC Code TI: Pour

    Data.gov (United States)

    National Aeronautics and Space Administration — Pour is a general-purpose information service framework designed to accommodate a wide variety of information types with support for high volume, low frequency...

  16. Cyanobacterial cellulose synthesis in the light of the photanol concept

    NARCIS (Netherlands)

    R.M. Schuurmans; H.C.P. Matthijs; L.J. Stal; K.J. Hellingwerf

    2014-01-01

    The detailed knowledge already available about cellulose synthases and their regulation, plus emerging insights into the process of cellulose secretion in cyanobacteria make cellulose an attractive polymer for the application of the photanol concept in an economically viable production process. By v

  17. Developpement et application d'un systeme mobile de laser terrestre pour quantifier le bilan sedimentaire des plages

    Science.gov (United States)

    Van-Wierts, Stefanie

    Au Québec maritime, l'érosion côtière est une problématique d'envergure, notamment sur les côtes de formations meubles. Les plages ont un rôle de zone tampon ayant comme fonction naturelle d'absorber l'énergie des vagues et donc d'assurer l'équilibre de certains écosystèmes et le maintien de l'écoumène en réduisant l'érosion de la côte. Les méthodes d'acquisition conventionnelles ne permettent pas de quantifier convenablement les changements morphosédimentaires d'une plage à l'échelle des cellules hydrosédimentaires. Le manque de méthode d'acquisition fiable et de données quantitatives mène à une surestimation ou à une sous-estimation de la disponibilité sédimentaire d'un système côtier. Pour contrer ces lacunes et afin de minimiser les coûts d'acquisition, un nouveau système mobile de LiDAR terrestre a été mis en place, permettant d'acquérir des données topographiques de l'estran, de la haute plage et des falaises. Le système multicapteurs comprend un LiDAR, un système de navigation à haute précision (IMU et D-GPS) et une caméra. L'ensemble des instruments et capteurs sont montés sur un véhicule de type tout-terrain. Le système a été évalué sur la zone côtière de la péninsule de Manicouagan. La comparaison des données LiDAR avec 1 050 points de référence géopositionnés au D-GPS montre une erreur verticale moyenne de 0,1 m sur les secteurs de plage. Les résultats montrent que le volume sédimentaire moyen des plages devant les zones où la ligne de rivage présente un ouvrage de protection en enrochement (12 m 3/m) est plus de trois fois plus faible que devant les secteurs à l'état naturel (35,5 m3/m). La moyenne des secteurs en transition, constituant les segments où une zone artificielle et une zone naturelle se chevauchent présentent un volume moyen de 28 m3/m. Aussi, les plages devant les secteurs anthropisés sont en moyenne près de 2 fois plus étroites (12,7 m) que devant les secteurs naturels (25

  18. Review: current international research into cellulose nanofibres and nanocomposites

    OpenAIRE

    Eichhorn, S. J.; Dufresne, A; Aranguren, M.; Marcovich, N. E.; Capadona, J R; Rowan, S. J.; Weder, Christoph; Thielemans, W.; Roman, M.; Renneckar, S.; Gindl, W.; Veigel, S.; Keckes, J.; Yano, H.; Abe, K.

    2010-01-01

    This paper provides an overview of recent progress made in the area of cellulose nanofibre-based nanocomposites. An introduction into the methods used to isolate cellulose nanofibres (nanowhiskers, nanofibrils) is given, with details of their structure. Following this, the article is split into sections dealing with processing and characterisation of cellulose nanocomposites and new developments in the area, with particular emphasis on applications. The types of cellulose nanofibres covered a...

  19. Architecture Logicielles pour des Applications hétérogènes, distribuées et reconfigurables

    OpenAIRE

    Louberry, Christine; Dalmau, Marc; Roose, Philippe

    2008-01-01

    The recent apparition of mobile wireless sensor aware to their physical environment and able to process information must allow proposing applications able to take into account their physical context and to react according to the changes of the environment. It suppose to design applications integrating both software and hardware components able to communicate. Applications must use context information from components to measure the quality of the proposed services in order to adapt them in rea...

  20. Fermentation Tecniques and Applications of Bacterial Cellulose: a Review Técnicas de fermentación y aplicaciones de la celulosa bacteriana: una revisión

    Directory of Open Access Journals (Sweden)

    Luz Dary Carreño Pineda

    2012-12-01

    Full Text Available Bacterial cellulose is a polymer obtained by fermentation with microorganismsfrom Acetobacter, Rhizobium, Agrobacterium and Sarcina genera. Amongthem, Acetobacter xylinum is the most efficient specie. This polymer hasthe same chemical composition of plant cellulose, but its conformation andphysicochemical properties are different, making it attractive for several applications, especially in the areas of food, separation processes, catalysis andhealth, due to its biocompatibility. However, the main problem is the production in mass that is constrained by low yield. It is therefore necessaryto develop some alternatives. This paper presents a review about synthesis,production, properties and principal applications of bacterial cellulose, as wellas some alternatives to reduce the difficulties for process scaling.La celulosa bacteriana es un polímero obtenido por fermentación con microrganismosde los géneros Acetobacter, Rhizobium, Agrobacterium y Sarcina, delas cuales la especie más eficiente es la Acetobacter Xylinum. Este polímero presenta la misma estructura química de la celulosa de origen vegetal, pero difiereen su conformación y propiedades fisicoquímicas, lo que lo hace atractivo para diversas aplicaciones, especialmente en las áreas de alimentos, procesosde separación, catálisis y en medicina, gracias a su biocompatibilidad. Sin embargo, el principal problema es la producción a gran escala limitada por losbajos rendimientos, lo que genera la necesidad de desarrollar alternativas que permitan disminuir o eliminar las causas de esta limitación. En este artículo se hace una revisión acerca de la síntesis, producción, propiedades y principales aplicaciones de la celulosa bacteriana, así como de algunas alternativas estudiadas para disminuir los inconvenientes en el escalamiento del proceso.

  1. Preparation of Photocrosslinked Fish Elastin Polypeptide/Microfibrillated Cellulose Composite Gels with Elastic Properties for Biomaterial Applications

    OpenAIRE

    Shinya Yano; Megumi Mori; Naozumi Teramoto; Makoto Iisaka; Natsumi Suzuki; Masanari Noto; Yasuko Kaimoto; Masashi Kakimoto; Michio Yamada; Eri Shiratsuchi; Toshiaki Shimasaki; Mitsuhiro Shibata

    2015-01-01

    Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N′-dicyclohexylcarbodiimide (DCC), a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI) to yield a photocrosslinkable fish elastin polypep...

  2. 隧道仰拱整体式浇筑设备的研制及应用%Development and Application of Integral Pouring Equipment of Tunnel Invert

    Institute of Scientific and Technical Information of China (English)

    徐冬青

    2012-01-01

    介绍了高速铁路双线隧道仰拱整体浇筑设备的研制及应用,并形成相应的施工工艺。采用自主研制的仰拱模架,能控制仰拱结构尺寸和弧线形状,大大改善了仰拱弧形段的质量,做到了内实外美。通过在沪昆客专项目六竹子隧道中的应用实践证明,仰拱模架在实际操作中切实可行,能有效加快施工进度,改善仰拱施工质量,具有推广应用价值。%This paper introduce in detail the development and application of integral pouring equipment of tunnel invert,which is formatted as the corresponding engineering process.By using self-developed arch frame to control the inverted arch structure size and arc shape,the invert arc section quality and appearance is greatly improved.The inverted arch frame is used in Shanghai-Kunming Passenger Dedicated Line,which in the actual operation is feasible,can effectively accelerate the construction progress,improve the quality of the invert construction,can be applied broadly.

  3. Flexible, highly graphitized carbon aerogels based on bacterial cellulose/lignin: Catalyst-free synthesis and its application in energy storage devices

    KAUST Repository

    Xu, Xuezhu

    2015-04-15

    Currently, most carbon aerogels are based on carbon nanotubes (CNTs) or graphene, which are produced through a catalyst-assisted chemical vapor deposition method. Biomass based organic aerogels and carbon aerogels, featuring low cost, high scalability, and small environmental footprint, represent an important new research direction in (carbon) aerogel development. Cellulose and lignin are the two most abundant natural polymers in the world, and the aerogels based on them are very promising. Classic silicon aerogels and available organic resorcinol-formaldehyde (RF) or lignin-resorcinol-formaldehyde (LRF) aerogels are brittle and fragile; toughening of the aerogels is highly desired to expand their applications. This study reports the first attempt to toughen the intrinsically brittle LRF aerogel and carbon aerogel using bacterial cellulose. The facile process is catalyst-free and cost-effective. The toughened carbon aerogels, consisting of blackberry-like, core-shell structured, and highly graphitized carbon nanofibers, are able to undergo at least 20% reversible compressive deformation. Due to their unique nanostructure and large mesopore population, the carbon materials exhibit an areal capacitance higher than most of the reported values in the literature. This property makes them suitable candidates for flexible solid-state energy storage devices. Besides energy storage, the conductive interconnected nanoporous structure can also find applications in oil/water separation, catalyst supports, sensors, and so forth. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Nouvelles électrodes modifiées avec cyclodextrines pour applications pharmaceutiques et biomédicales

    OpenAIRE

    Fritea, Luminita

    2015-01-01

    The cyclodextrin modified electrodes with enhanced analytical performances represent an attractive promise for the future development of electrochemical (bio)sensors and remain a very active field of research for a wide range of applications in many areas, including pharmaceutical and biomedical analysis. The aim of this study was to develop novel cyclodextrin modified electrodes for pharmaceutical and biomedical applications. The β-cyclodextrin influence was investigated both in solution and...

  5. CONKER : un modèle de répartition pour processus communicants. Application à OCCAM

    OpenAIRE

    Riveill, Michel

    1987-01-01

    This theisis proposes a model CONKER for distributed systems of communicating sequential processes (Hoare 's CSP). An application program will be structured in CONKER as a set of processes (processing objects) commmunicating throught a set of connectors (commun ication-synchronization objects).Each connector implement a specific and possibly complex communication protocol between application processes which still use the CSP basic communication protocol (rendez-vous for input-output primitive...

  6. Advanced and Integrated Petrophysical Characterization for CO2 Storage: Application to the Ketzin Site Caractérisation pétrophysique intégrée pour le stockage de CO2 : application au site de Ketzin

    Directory of Open Access Journals (Sweden)

    Fleury M.

    2013-06-01

    from 100 to 300 mD. Two zones were identified on the logs characterized by two different irreducible saturation ranging from 15 up to 35%. The measured relative permeability curves show a sharp decrease of the water effective permeability and suggest that a saturation lower than 50% cannot be reached in practice. The exponent of the resistivity index curve is about 1.7, lower than the default value of 2. The caprock has a permeability of 27 nD, a porosity around 15% and a pore diffusivity of 0.8 x 10-9 m2/s La simulation et le suivi d’un stockage de CO2 requiert des données pétrophysiques spécifiques. Nous présentons un ensemble d’expériences applicables à tout stockage et à toute couverture, fournissant des données pour des simulations numériques réalistes du potentiel de stockage et de l’injection. Ces expériences sont intégrées avec les données diagraphiques pour l’estimation de la porosité, la saturation irréductible, la pression capillaire et la perméabilité relative de l’eau en drainage, la saturation en gaz résiduelle, les relations résistivité-saturation et les propriétés de transport de la couverture (perméabilité et diffusivité. Le cas considéré est l’aquifère salin du Trias dans le contexte du projet CO2SINK, le premier site expérimental de stockage en Allemagne situé près de Ketzin. Nous avons utilisé des méthodes de mesure nécessitant des durées raisonnables tout en restant représentatives des processus in situ. Pour le transport diphasique, nous avons utilisé la centrifugation. Pour la résistivité, nous avons utilisé une méthode rapide « Fast Resistivity Index Measurement » (FRIM en drainage et imbibition, en condition ambiante et en condition de stockage. Pour la caractérisation de la couverture, nous avons utilisé une technique rapide RMN (Résonance Magnétique Nucléaire utilisant le deutérium comme traceur pour la mesure de diffusion et une méthode stationnaire innovante pour la mesure de

  7. Single-cell protein from waste cellulose

    Science.gov (United States)

    Dunlap, C. E.; Callihan, C. D.

    1973-01-01

    The recycle, reuse, or reclamation of single cell protein from liquid and solid agricultural waste fibers by a fermentation process is reported. It is shown that cellulose comprises the bulk of the fibers at 50% to 55% of the dry weight of the refuse and that its biodegradability is of prime importance in the choice of a substrate. The application of sodium hydroxide followed by heat and pressure serves to de-polymerize and disrupt lignin structure while swelling the cellulose to increase water uptake and pore volume. Some of the lignin, hemi-celluloses, ash, and cellulose of the material is hydrolized and solubilized. Introduction of microorganisms to the substrate fibers mixed with nutrients produces continuous fermentation of cellulose for further protein extraction and purification.

  8. Application of silicified microcrystalline cellulose (Prosolv) as a polymer carrier of Epilobium parviflorum Schreb. extract in oral solid drug form.

    Science.gov (United States)

    Marczyński, Zbigniew; Zgoda, Marian Mikołaj; Jambor, Jerzy

    2007-01-01

    Direct tableting is simpler and more cost-effective from the point of view of good manufacturing practice (GMP) than wet granulation or dry compacting. Thus, pharmaceutical industry more and more frequently uses this particular process. Only few therapeutic substances form under compression tablets meeting current requirements. Very often additional adjuvants must be used. These substances have the ability of increasing plastic deformation and tablet mass liquidity. Microcrystalline cellulose belongs to the best adjuvant substances of the type. It has binding, disintegrating and improving liquidity properties. This study aims at investigating the usefulness of selected high-molecular substances with particular consideration of silici-fled microcrystalline cellulose (Prosolv) and croscarmellose sodium (Vivasol) as a carrier of E. parviflorum Schreb. extract in oral solid drug form in the process of direct tab-leting. The manufactured tablets were subjected to morphological tests and pharmaceutical availability tests of biologically active substances from a tablet to the acceptor fluid. The investigations were based on general and detailed principles of Polish Pharmacopoeia VI. The obtained results allow to state that the applied high-molecular adjuvant substances proved to be useful in adequate proportions in the production of tablets from dry extract from Epilobium parviflo-rum Schreb. Generally, a significant shortening of the tablets disintegration time was obtained as compared to earlier produced tablets with the method of initial granulation. The tablets formed from E. parviflorum Schreb. extract with silicified microcrystalline cellulose (Prosolv SMCC 50) and croscarmellose sodium can be included into preparations of short dissolution time of the therapeutic substance. PMID:17957946

  9. Biopolymer electrolytes based on blend of kappa-carrageenan and cellulose derivatives for potential application in dye sensitized solar cell

    International Nuclear Information System (INIS)

    In this work, carboxymethyl kappa-carrageenan was used as the principle host for developing new biopolymer electrolytes based on the blend of carboxymethyl kappa-carrageenan/carboxymethyl cellulose. The blending of carboxymethyl cellulose into carboxymethyl kappa-carragenan was found to be a promising strategy to improve the material properties such as conductive properties. The electrolyte samples were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic mechanical analysis, electrochemical impedance spectroscopy, ionic transference number measurement and linear sweep voltammetry in order to investigate their structural, thermal and electrochemical properties. Impedance study showed that the ionic conductivity increased with the increment of ammonium iodide concentration. The highest room temperature ionic conductivity achieved was 2.41 × 10−3 S cm−1 at 30 wt% of the salt. The increment of conductivity was due to the increase of formation of transient cross-linking between the carboxymethyl kappa-carrageenan/carboxymethyl cellulose chains and the doping salt as indicated the Tg trend. The conductivity was also attributed by the increase in the number of charge carriers in the biopolymer electrolytes system. The interactions between polymers and salt were confirmed by FTIR study. The transference number measurements showed that the conductivity was predominantly ionic. Temperature dependent conductivity study showed that conductivity increased with the reciprocal of temperature. The conductivity-temperature plots suggested that the conductivity obeyed the Vogel–Tammann–Fulcher relation and the activation energy for the best conducting sample was 0.010 eV. This system was used for the fabrication of dye sensitized solar cells, FTO/TiO2-dye/CMKC/CMCE-NH4I + I2/Pt. The fabricated cell showed response under light intensity of 100 mW cm−2 with efficiency of 0.13% indicating that the blend biopolymer system has

  10. Supercritical fluid assisted process for the generation of cellulose acetate loaded structures, potentially useful for tissue engineering applications.

    Science.gov (United States)

    Cardea, Stefano; Scognamiglio, Mariarosa; Reverchon, Ernesto

    2016-02-01

    Supercritical CO2 phase inversion offers an alternative to obtain solvent free structures with short processing times and preservation of the morphology. We prepared cellulose acetate structures loaded with drug (ibuprofen) to perform experiments at pressures and temperatures ranging between 150 and 250 bars and 35 and 55 °C. The structures were properly characterized by SEM, EDX and DSC; drug controlled release experiments were also performed. Analyses showed that the operating conditions strongly influenced the structure morphology, porosity and drug release profiles. Indeed, connected microparticles, nanofibrous networks and cellular membranes were produced, which have generated different drug release profiles. PMID:26652399

  11. Les " affaires " et la mise en application des normes internationales, des défis et des opportunités pour l'enseignement de la comptabilité

    OpenAIRE

    Colasse, Bernard

    2005-01-01

    La deuxième partie de cette conférence a été publiée dans la Revue Française de Comptabilité (n° 285, février 2006, pp. 37-40) sous le titre "IFRS : un défi et une opportunité pour l'enseignement de la comptabilité" National audience Selon l'auteur, les " affaires " et la mise en application des normes internationales constituent à la fois un formidable défi et une formidable opportunité pour un enseignement de la comptabilité resté trop technique et trop révérencieux envers la normalis...

  12. Etude des mécanismes de conduction électrique dans des matériaux composites pour application d'anode inerte. Relation "conductivité-composition/microstructure"

    OpenAIRE

    Bes, Guillaume

    2008-01-01

    No english abstract ... La recherche de matériaux pour l'application "anode inerte " est un enjeu important pour le monde de l'industrie de l'aluminium. Les conditions d'utilisation d'un tel matériau sont sévères et les propriétés qui lui sont demandées sont assez nombreuses. L'anode doit ainsi assurer son rôle de conducteur électrique dans le bain d'électrolyse à haute température tout en résistant aux fortes contraintes thermomécaniques et chimiques (corrosion en partie aérienne et dans ...

  13. Dépistage de la dépression du postpartum par les infirmières Petite Enfance: quelles échelles scientifiquement reconnues et quelles applications pour la pratique ? : Travail de Bachelor

    OpenAIRE

    Ausoni, Lisa; Veillon Sahli, Aline; Espuna, Frédérique

    2013-01-01

    Contexte : la dépression du postpartum touche 13% des mères et peut avoir de graves conséquences sur la mère et l’enfant. Elle est souvent banalisée et sous-diagnostiquée. Les infirmières Petite Enfance des services de soins à domicile réalisent dans leur mission le dépistage de cette affection. Objectif: cette revue de la littérature a pour but d'identifier quelles échelles de dépistage sont scientifiquement reconnues et quelles recommandations sont proposées pour leur application pratique. ...

  14. Comment améliorer la dérive des résonateurs à quartz pour applications spatiales ?

    OpenAIRE

    Bruno, Delmas,

    2009-01-01

    Bulk acoustic wave quartz resonators have been used to stabilize electric oscillators for about hundred years. Amazing quartz material properties and technical improvement explain this lifespan. For spatial applications, an intervention on such component is clearly impossible. Then, the frequency shift, which a part is due to aging, has to be reduced and well controlled over many years. The frequency changes systematically with time under the impact of physical phenomenon variation. Here we s...

  15. Comment améliorer la dérive des résonateurs à quartz pour applications spatiales ?

    OpenAIRE

    Delmas, Bruno

    2009-01-01

    Bulk acoustic wave quartz resonators have been used to stabilize electric oscillators for about thousand years. Amazing quartz material properties and technical improvement explain this lifespan. For spatial applications, components intervention is clearly impossible. Then, the frequency shift, which a part is due to aging, has to be reduced and well controled over many years. The frequency changes systematically with time under the impact of physical phenomenon variation. Here we sum up them...

  16. Electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  17. Cellulose synthase interacting protein: A new factor in cellulose synthesis

    OpenAIRE

    Gu, Ying; Somerville, Chris

    2010-01-01

    Cellulose is the most abundant biopolymer on earth. The great abundance of cellulose places it at the forefront as a primary source of biomass for renewable biofuels. However, the knowledge of how plant cells make cellulose remains very rudimentary. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes. The only known components of cellulose synthase complexes are cellulose synthase (CESA) proteins until the re...

  18. Critère de fatigue polycyclique pour des matériaux anisotropes : application aux monocristaux

    Science.gov (United States)

    Cano, Florian; Constantinescu, Andrei; Maitournam, Habibou

    2004-02-01

    The high-cycle fatigue criteria based on a macroscopic-mesoscopic scale interpretation, initiated by Dang Van, were used essentially for polycrystalline materials. In the existing criteria the material isotropy at both mesoscopic and macroscopic scales plays a key role. The purpose of this paper is to revisit the macroscopic to mesoscopic fatigue approach taking into account the material anisotropy and some results obtained by Bui. The possible applications are some anisotropic steels or monocrystalline structures such as stitanium turbine blades. To cite this article: F. Cano et al., C. R. Mecanique 332 (2004).

  19. ANALYSE ET SYNTHESE D'UNE ARCHITECTURE COOPERATIVE POUR LA COMMANDE TOLERANTE AUX DEFAUTS - APPLICATION A UN SYSTEME AERONAUTIQUE

    OpenAIRE

    Cieslak, Jérôme

    2007-01-01

    This thesis discusses the design of an active Fault Tolerant Control (FTC) strategy for improvement of the operational control capability of the safety critical systems. The FTC strategy works in such a way that once a fault is detected by the Fault Detection and Isolation (FDI) unit, a compensation loop is activated for safe recovery. A key feature of the proposed strategy is that the design of the FTC loop is done independently of the nominal control law already in place. For a given applic...

  20. Properties of a recombinant beta-glucosidase from polycentric anaerobic fungus Orpinomyces PC-2 and its application for cellulose hydrolysis.

    Science.gov (United States)

    Li, Xin-Liang; Ljungdahl, Lars G; Ximenes, Eduardo A; Chen, Huizhong; Felix, Carlos R; Cotta, Michael A; Dien, Bruce S

    2004-01-01

    A beta-glucosidase (BglA, EC 3.2.1.21) gene from the polycentric anaerobic fungus Orpinomyces PC-2 was cloned and sequenced. The enzyme containing 657 amino acid residues was homologous to certain animal, plant, and bacterial beta-glucosidases but lacked significant similarity to those from aerobic fungi. Neither cellulose- nor protein-binding domains were found in BglA. When expressed in Saccharomyces cerevisiae, the enzyme was secreted in two forms with masses of about 110 kDa and also found in two forms associated with the yeast cells. Km and Vmax values of the secreted BglA were 0.762 mM and 8.20 micromol/(min x mg), respectively, with p-nitrophenyl-beta-D-glucopyranoside (pNPG) as the substrate and 0.310 mM and 6.45 micromol/(min.mg), respectively, for the hydrolysis of cellobiose. Glucose competitively inhibited the hydrolysis of pNPG with a Ki of 3.6 mM. Beta-glucosidase significantly enhanced the conversion of cellulosic materials into glucose by Trichoderma reesei cellulase preparations, demonstrating its potential for use in biofuel and feedstock chemical production. PMID:15054209

  1. Preparation of cellulose nanocrystals from asparagus (Asparagus officinalis L.) and their applications to palm oil/water Pickering emulsion.

    Science.gov (United States)

    Wang, Wenhang; Du, Guanhua; Li, Cong; Zhang, Hongjie; Long, Yunduo; Ni, Yonghao

    2016-10-20

    Nano cellulosic materials as promising emulsion stabilizers have attracted great interest in food industry. In this paper, five different sized cellulose nanocrystals (CNC) samples were prepared from stem of Asparagus officinalis L. using the same sulfuric acid hydrolysis conditions but different times (1.5, 2, 2.5, 3.0, and 3.5h). The sizes of these CNC ranged from 178.2 to 261.8nm, with their crystallinity of 72.4-77.2%. The CNC aqueous dispersions showed a typical shear thinning behavior. In a palm oil/water (30/70, v/v) model solution, stable Pickering emulsions were formed with the addition of CNC, and their sizes are in the range of 1-10μm based on the optical and confocal laser scanning microscopy (CLSM) observation. The CNC sample prepared at 3h hydrolysis time, showed a relative efficient emulsion capacity for palm oil droplets, among these CNCs. Other parameters including the CNC, salt, and casein concentrations on the emulsion stability were studied. PMID:27474537

  2. Obstacle detection contribution for automotive applications; Contribution a la detection d'obstacles pour la voiture intelligente

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, M.

    1997-12-05

    On the one hand, this Ph-D Thesis deals with a new architectural approach for automotive applications implementing heterogeneous sensor data fusion, and on the other hand, it explains the data pre-processing algorithm of a microwave radar. Firstly, the analysis of both PROCHIP2 and PROLAB2 obstacle detection demonstrators (cf. the European PROMETHEUS research program about smart cars) has led us to propose a new functional architecture. Our approach introduces a sensor data pre-processing level. Data are then running at the local sensor before being transferred to data fusion architectures (that classically receives data whose meaning has also been noised by the application distribution). Secondly, an elementary simulator has been designed in order to complement our database composed of experimental microwave radar data. It is able to generate radar data for basic highway traffic scenarios. With both experimental and simulated data, a deterministic radar data pre-processing algorithm has been designed. It reduces the amount of data to be transferred by converting the local radar data into a higher semantic information: it gives more pertinent data (for example: velocities...) to the data fusion level; in particular, it predicts the obstacle path. Finally, some perspectives have been set out. Firstly, an H {infinity} estimation approach is used to reduce the data disruption effect that alters the radar data and, secondly, a controller has been proposed with the goal of decreasing the effect of car pitching. (author)

  3. Etude de nano-transistors à faible pente sous le seuil pour des applications très basse consommation

    OpenAIRE

    Villalon, Anthony

    2014-01-01

    Le transistor à effet tunnel bande à bande (TFET) est une architecture PIN à grille capable d’obtenir une pente sous le seuil inférieure à 60mV/dec à température ambiante, ce qui représente un avantage par rapport au MOSFET dans le cas d’applications basse consommation. L’objectif de cette thèse est d’étudier et de caractériser des TFETs fabriqués au CEA-LETI (sur substrats SOI avec les procédés standards CMOS), afin de comprendre et d’optimiser ces dispositifs. La première génération de TFET...

  4. Etude de transistors en couches minces à base de silicium polymorphe pour leur application aux écrans plats à matrice active LCD ou OLED

    OpenAIRE

    Brochet, Julien,

    2011-01-01

    Ce travail a pour objectifs d'apporter des connaissances au niveau des propriétés électriques de transistors en couches minces (TFTs) à base de silicium polymorphe (pm-Si :H), ainsi qu'au niveau de la structure du matériau polymorphe. Nous nous sommes également intéressé à une nouvelle méthode de cristallisation d'une couche de silicium amorphe par interférométrie laser qui présente un fort potentiel pour le développement de matrice active en silicium polycristallin de grandes dimensions. Nou...

  5. Application des techniques multiporteuses de type OFDM pour les futurs systèmes de télécommunications par satellite

    OpenAIRE

    Ho, Anh Tai

    2009-01-01

    Cette thèse étudie la possibilité d'appliquer les techniques de modulations multiporteuses de type OFDM dans les futurs systèmes de communications par satellite. Elle traite notamment du problème de synchronisation au niveau récepteur pour les systèmes de diffusion par satellite en bande Ka. L'objectif est de proposer une structure de réception ayant besoin du moins de ressources possibles pour synchroniser afin d'optimiser l'efficacité spectrale du système et obtenir un gain par rapport à un...

  6. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 Å Resolution

    OpenAIRE

    Juan Du; Venkata Vepachedu; Sung Hyun Cho; Manish Kumar; B Tracy Nixon

    2016-01-01

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalyt...

  7. The Characterization and Application of Grafted Polypropylene and Polystyrene Treated with Epichlorohydrin Coupled with Cellulose or Starch for Immobilization Process

    International Nuclear Information System (INIS)

    The direct irradiation induced grafting of acrylamide (AAm) onto polypropylene (PP) films and polystyrene (PSty) films for crosslinking of acrylamide grafted polypropylene and polystyrene films with epichlorohydrin as spacer was studied. The reaction of polyamide-epichlorohydrin with cellulose and starch has been carried out, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and thermal gravimetric analysis (TGA) were carried out before and after immobilized enzyme to confirm the characterization of the polymer as well as the α- amylase enzyme immobilized one. The physico-chemical parameters of the immobilized enzymes and the kinetics of co-enzymes-polymer catalyzed reactions and stability were measured. A direct comparison was made between the products activity of the free and the immobilized preparations

  8. Preparation and Application of Tripeptide-cellulose Ester%三肽纤维素酯的制备及应用研究

    Institute of Scientific and Technical Information of China (English)

    李杨; 朱进科; 李连杰; 蒋登高

    2016-01-01

    Tripeptide-cellulose ester ( TPC) was synthesized by sequent acyl chlorination, esterification, peptide elongation and amino modification using microcrystalline cellulose as raw material and N-(9-fluorenylmethoxycarbonyl)-L-proline(FMOC-L-Pro-OH), N-(9-fluorenylmethoxycarbonyl)-L-valinamide-L-phenylalanine(FMOC-L-Val-L-Phe-OH), 3,5-dinitrobenzoic acid as derivatization reagents. The experimental results showed that during the synthesis process, esterification, a key step, was performed firstly, and followed by the extension of peptide chain. The effects of various experimental factors on esterification and substitution degree ( DS ) were investigated. The optimal condition was described as that the mass concentration of avicel in LiCl/DMAc 20 g/L, the molar ratio of —C(O)Cl to the hydroxyl content of cellulose 3∶1, reaction temperature 100℃ and reaction time 20 h. By the further peptide elongation and amino modification, the tripeptide-cellulose ester with DS 2. 15 was synthesized. The structure and properties were then characterized by using Fourier transform infrared spectroscopy, elemental analysis, X-ray diffraction and thermogravimetric analysis. The results showed that the modification of peptide by 3,5-dinitrobenzoic acid was successful and the synthesis process was feasible. With the alteration of precipitants, the intramolecular hydrogen bond was different and the obtained derivatives had different characteristics and functionalities. The tripeptide-cellulose ester precipitated in methanol was good enteric-coating material with good shading effect and rapid disintegration, but the physiological toxicity needed further study. The tripeptide-cellulose ester ( using water as the precipitant) could be coated onto silica gel to get a chiral stationary phase, which has a wider application than previous coated-cellulose chiral stationary phase. In addition, the stable chemical resistance of tripeptide-cellulose ester was particularly suitable for the

  9. Radiation degradation of cellulose

    International Nuclear Information System (INIS)

    The application of straw and other cellulose polymers as feedstuff for ruminants is limited by its low digestibility. During recent decades it was attempted to increase the digestibility of straw by several chemical and physical methods. In this work some results of the degradation of gamma and electron treated wheat straw are reported. Complex methods of treatment (e.g. radiation influence and influence of lyes) are taken into consideration. In vitro-experiments with radiation treated straw show that the digestibility can be increased from 20% up to about 80%. A high pressure liquid chromatography method was used to analyze the hydrolysates. The contents of certain species of carbohydrates in the hydrolysates in dependence on the applied dose are given

  10. Cellulose-Based Bio- and Nanocomposites: A Review

    Directory of Open Access Journals (Sweden)

    Susheel Kalia

    2011-01-01

    Full Text Available Cellulose macro- and nanofibers have gained increasing attention due to the high strength and stiffness, biodegradability and renewability, and their production and application in development of composites. Application of cellulose nanofibers for the development of composites is a relatively new research area. Cellulose macro- and nanofibers can be used as reinforcement in composite materials because of enhanced mechanical, thermal, and biodegradation properties of composites. Cellulose fibers are hydrophilic in nature, so it becomes necessary to increase their surface roughness for the development of composites with enhanced properties. In the present paper, we have reviewed the surface modification of cellulose fibers by various methods. Processing methods, properties, and various applications of nanocellulose and cellulosic composites are also discussed in this paper.

  11. Cellulose-silica aerogels.

    Science.gov (United States)

    Demilecamps, Arnaud; Beauger, Christian; Hildenbrand, Claudia; Rigacci, Arnaud; Budtova, Tatiana

    2015-05-20

    Aerogels based on interpenetrated cellulose-silica networks were prepared and characterised. Wet coagulated cellulose was impregnated with silica phase, polyethoxydisiloxane, using two methods: (i) molecular diffusion and (ii) forced flow induced by pressure difference. The latter allowed an enormous decrease in the impregnation times, by almost three orders of magnitude, for a sample with the same geometry. In both cases, nanostructured silica gel was in situ formed inside cellulose matrix. Nitrogen adsorption analysis revealed an almost threefold increase in pores specific surface area, from cellulose aerogel alone to organic-inorganic composite. Morphology, thermal conductivity and mechanical properties under uniaxial compression were investigated. Thermal conductivity of composite aerogels was lower than that of cellulose aerogel due to the formation of superinsulating mesoporous silica inside cellulose pores. Furthermore, composite aerogels were stiffer than each of reference aerogels. PMID:25817671

  12. Nanosized Cellulose Fibrils as Stabilizer of Emulsions

    OpenAIRE

    Xhanari, Klodian

    2011-01-01

    Pickering emulsions have been a subject of research for many years due to their practical applications not only in everyday life products but also in industry. The stability of these emulsions is due to the irreversible adsorption of colloid particles at the oil/water interface which prevents droplet coalescence. Cellulose materials are among the different types of particles used as stabilizers. Most of the studies report the use of native cellulose as stabilizer of oil-in-water emulsions due...

  13. Nanofibrillar cellulose films for controlled drug delivery.

    Science.gov (United States)

    Kolakovic, Ruzica; Peltonen, Leena; Laukkanen, Antti; Hirvonen, Jouni; Laaksonen, Timo

    2012-10-01

    Nanofibrillar cellulose (NFC) (also referred to as cellulose nanofibers, nanocellulose, microfibrillated, or nanofibrillated cellulose) has gotten recent and wide attention in various research areas. Here, we report the application of nanofibrillar cellulose as a matrix-former material for long-lasting (up to three months) sustained drug delivery. Film-like matrix systems with drug loadings between 20% and 40% were produced by a filtration method. This simple production method had an entrapment efficacy>90% and offers a possibility for the film thickness adjustment as well as applicability in the incorporation of heat sensitive compounds. The films had excellent mechanical properties suitable for easy handling and shape tailoring of the drug release systems. They were characterized in terms of the internal morphology, and the physical state of the encapsulated drug. The drug release was assessed by dissolution tests, and suitable mathematical models were used to explain the releasing kinetics. The drug release was sustained for a three month period with very close to zero-order kinetics. It is assumed that the nanofibrillar cellulose film sustains the drug release by forming a tight fiber network around the incorporated drug entities. The results indicate that the nanofibrillar cellulose is a highly promising new material for sustained release drug delivery applications. PMID:22750440

  14. The Synthesis of a Novel Cellulose Physical Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2014-01-01

    Full Text Available Cellulose possessing β-cyclodextrin (β-CD was used as a host molecule and cellulose possessing ferrocene (Fc as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC, ultraviolet spectroscopy (UV, and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO as an oxidant and glutathione (GSH as a reductant. In this study, a physical gel based on β-CD-cellulose/Fc-cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol-gel transition. The compressive strength of the Fc-cellulose/β-CD-cellulose gel increased with increased cellulose concentration. The host-guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus-responsive, healing material in biomedical applications.

  15. Novel UV cured polymers for coating and recycling cellulosics, application to a unique paper / veneer from the waste banana tree

    International Nuclear Information System (INIS)

    Work involving UV curing and cure-grafting processes on material from the waste banana tree has been performed. Water compatible oligomers of unique structure and processing novel properties have been used in this treatment. The material from the waste banana tree has been obtained by a peeling process and can be treated either as a type of paper or as a modified timber veneer leading to two general lines of potential commercial products. The peeled product is coated with formulations containing the novel oligomers and UV cured. The advantages of using these unique water compatible oligomers in all general UV curing systems are discussed. The effect of including nanoparticle fillers in these coating formulations is considered. The effect of the presence of lignin in the banana ply paper on the curing process is examined by comparing the banana ply paper curing data with analogous results from a pure cellulose Whatman 41 paper. Two UV lamps have been used in these studies, a Fusion F-300 and a Con-Trol-Cure LED, the latter shown to be safer from body exposure considerations because it operates in a 385-405 nm wavelength band. A mechanism for the curing and cure-grafting process on banana ply paper/veneer has been proposed. The commercial potential of this process is discussed especially the economic advantages of using the banana ply paper/veneer which is not chemically pulped. (Author)

  16. Cellulosic nanowhiskers. Theory and application of light scattering from polydisperse spheroids in the Rayleigh-Gans-Debye regime.

    Science.gov (United States)

    Braun, Birgit; Dorgan, John R; Chandler, John P

    2008-04-01

    Mathematical treatment of light scattering within the Rayleigh-Gans-Debye limit for spheroids with polydispersity in both length and diameter is developed and experimentally tested using cellulosic nanowhiskers (CNW). Polydispersity indices are obtained by fitting the theoretical formfactor to experimental data. Good agreement is achieved using a polydispersity of 2.3 for the length, independent of the type of acid used. Diameter polydispersities are 2.1 and 3.0 for sulfuric and hydrochloric acids, respectively. These polydispersities allow the determination of average dimensions from the z-average mean-square radius (z) and the weight-average molecular weight (M w) easily obtained from Berry plots. For cotton linter hydrolyzed by hydrochloric acid, the average length and diameter are 244 and 22 nm. This compares to average length and diameter of 272 and 13 nm for sulfuric acid. This study establishes a new light-scattering methodology as a quick and robust tool for size characterization of polydisperse spheroidal nanoparticles. PMID:18357993

  17. Preparation of photocrosslinked fish elastin polypeptide/microfibrillated cellulose composite gels with elastic properties for biomaterial applications.

    Science.gov (United States)

    Yano, Shinya; Mori, Megumi; Teramoto, Naozumi; Iisaka, Makoto; Suzuki, Natsumi; Noto, Masanari; Kaimoto, Yasuko; Kakimoto, Masashi; Yamada, Michio; Shiratsuchi, Eri; Shimasaki, Toshiaki; Shibata, Mitsuhiro

    2015-01-01

    Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC) were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO). First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N'-dicyclohexylcarbodiimide (DCC), a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI) to yield a photocrosslinkable fish elastin polypeptide. The product was dissolved in DMSO and irradiated with UV light in the presence of a radical photoinitiator. We obtained hydrogels successfully by substitution of DMSO with water. The composite gel with MFC was prepared by UV irradiation of the photocrosslinkable elastin polypeptide mixed with dispersed MFC in DMSO, followed by substitution of DMSO with water. The tensile test of the composite gels revealed that the addition of MFC improved the tensile properties, and the shape of the stress-strain curve of the composite gel became more similar to the typical shape of an elastic material with an increase of MFC content. The rheology measurement showed that the elastic modulus of the composite gel increased with an increase of MFC content. The cell proliferation test on the composite gel showed no toxicity. PMID:25584682

  18. Preparation of Photocrosslinked Fish Elastin Polypeptide/Microfibrillated Cellulose Composite Gels with Elastic Properties for Biomaterial Applications

    Directory of Open Access Journals (Sweden)

    Shinya Yano

    2015-01-01

    Full Text Available Photocrosslinked hydrogels reinforced by microfibrillated cellulose (MFC were prepared from a methacrylate-functionalized fish elastin polypeptide and MFC dispersed in dimethylsulfoxide (DMSO. First, a water-soluble elastin peptide with a molecular weight of ca. 500 g/mol from the fish bulbus arteriosus was polymerized by N,N′-dicyclohexylcarbodiimide (DCC, a condensation reagent, and then modified with 2-isocyanatoethyl methacrylate (MOI to yield a photocrosslinkable fish elastin polypeptide. The product was dissolved in DMSO and irradiated with UV light in the presence of a radical photoinitiator. We obtained hydrogels successfully by substitution of DMSO with water. The composite gel with MFC was prepared by UV irradiation of the photocrosslinkable elastin polypeptide mixed with dispersed MFC in DMSO, followed by substitution of DMSO with water. The tensile test of the composite gels revealed that the addition of MFC improved the tensile properties, and the shape of the stress–strain curve of the composite gel became more similar to the typical shape of an elastic material with an increase of MFC content. The rheology measurement showed that the elastic modulus of the composite gel increased with an increase of MFC content. The cell proliferation test on the composite gel showed no toxicity.

  19. Highly thermostable and pH-stable cellulases from Aspergillus niger NS-2: properties and application for cellulose hydrolysis.

    Science.gov (United States)

    Bansal, Namita; Janveja, Chetna; Tewari, Rupinder; Soni, Raman; Soni, Sanjeev Kumar

    2014-01-01

    Optimization of cultural conditions for enhanced cellulase production by Aspergillus niger NS-2 were studied under solid-state fermentation. Significant increase in yields (CMCase 463.9 ± 20.1 U/g, FPase 101.1 ± 3.5 U/g and β-glucosidase 99 ± 4.0 U/g) were obtained under optimized conditions. Effect of different nutritional parameters was studied to induce the maximum production of cellulase complex. Scale-up studies for enzyme production process were carried out. Characterization studies showed that enzymes produced by A. niger NS-2 were highly temperature- and pH stable. At 50 °C, the half life for CMCase, FPase, β-glucosidase were approximately 240 h. Cellulases from A. niger NS-2 were stable at 35 °C for 24 h over a broader pH range of 3.0-9.0. We examined the feasibility of using steam pretreatment to increase the saccharification yields from various lignocellulosic residues for sugar release which can potentially be used in bioethanol production. Saccharification of pretreated dry potato peels, carrot peels, composite waste mixture, orange peels, onion peels, banana peels, pineapple peels by crude enzyme extract from A. niger NS-2, resulted in very high cellulose conversion efficiencies of 92-98 %. PMID:24052336

  20. Extensomètres à fibre optique pour le génie civil : Etat de l'art, applications industrielles et perspectives

    OpenAIRE

    Delepine Lesoille, Sylvie; MERLIOT, Erick; Gautier, Yves

    2008-01-01

    Les capteurs à fibre optique sont des outils exceptionnels pour le contrôle de santé des structures. Le présent article vise à dresser l'état de l'art des extensomètres à fibre optique en génie civil, près de 20 ans après leurs premiers développements. Après des descriptions béotiennes de la fibre optique, les différents types de capteurs à fibre optique sont présentés de manière pragmatique, en listant les performances et les limitations, l'état d'avancement, et pour les plus avancées les fo...

  1. Contribution à la conception de circuits intégrés analogiques en technologie CMOS basse tension pour application aux instruments d'observation de la Terre

    OpenAIRE

    Standarovski, Denis

    2005-01-01

    Le présent mémoire de thèse s'inscrit dans la problématique d'intégration de chaînes pour traitement du signal vidéo issu d'un capteur CCD dédiées aux instruments d'observation de la Terre. La solution présentée à travers cette étude consiste à concevoir des circuits intégrés spécifiques (ASIC) analogiques avec des technologies CMOS sub-microniques basse-tension, principalement développées pour les circuits numériques complexes. Dans une première partie, nous présentons le contexte de l'étude...

  2. Isolation of cellulose microfibrils - An enzymatic approach

    Directory of Open Access Journals (Sweden)

    Sain, M.

    2006-11-01

    Full Text Available Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.

  3. Procédé de nitruration d'un alliage de titane superélastique pour des applications biomédicales Nitriding process of a superelastic titanium alloy for biomedical applications

    Directory of Open Access Journals (Sweden)

    Bedouin Yvan

    2013-11-01

    Full Text Available Dans le cadre de ce travail, nous avons mis au point un protocole de nitruration appliqué à un alliage Ti-Nb de type beta, biocompatible et qui présente des propriétés de superélasticité. Cet alliage a ainsi subi un traitement de nitruration en phase gazeuse suivi d'un traitement de recristallisation en phase beta et d'une trempe dans l'eau. Avec ce protocole, l'alliage est nitruré en surface et sa caractéristique superélastique est maintenue. Cet ensemble de propriétés mécaniques peut s'avérer très intéressante pour différentes applications biomédicales. Within the framework of this work, we developed a nitriding process on biocompatible Ti-Nb based beta-type alloy which presents superelastic property. This alloy underwent a nitriding treatment, which was followed by a recrystallization in the beta phase domain before quenching in water. With this protocol, the alloy is thus hardened by the presence of the nitride on the surface while its superelastic characteristic is maintained. This whole of mechanical properties can be very interesting for various biomedical applications.

  4. Linguistique pour germanistes

    OpenAIRE

    Rühl, Marco

    2014-01-01

    Comme le présent ouvrage se veut un «guide» des premiers pas en linguistique allemande, illustratif plutôt qu'exhaustif pour ne pas être trop technique, il a nécessité un mode de présentation quelque peu particulier. A plusieurs reprises, le lecteur trouvera des paragraphes en caractères plus petits dont la fonction est la suivante. Si ces paragraphes sont relativement longs, ils approfondissent un sujet abordé par la section dans laquelle ils apparaissent. Dans ce cas, le lecteur pourra les ...

  5. Preparation and characterization of hydroxypropyl methyl cellulose films containing stable BCS Class II drug nanoparticles for pharmaceutical applications.

    Science.gov (United States)

    Sievens-Figueroa, Lucas; Bhakay, Anagha; Jerez-Rozo, Jackeline I; Pandya, Natasha; Romañach, Rodolfo J; Michniak-Kohn, Bozena; Iqbal, Zafar; Bilgili, Ecevit; Davé, Rajesh N

    2012-02-28

    The design and feasibility of a simple process of incorporating stable nanoparticles into edible polymer films is demonstrated with the goal of enhancing the dissolution rate of poorly water soluble drugs. Nanosuspensions produced from wet stirred media milling (WSMM) were transformed into polymer films containing drug nanoparticles by mixing with a low molecular weight hydroxylpropyl methyl cellulose (HPMC E15LV) solution containing glycerin followed by film casting and drying. Three different BCS Class II drugs, naproxen (NPX), fenofibrate (FNB) and griseofulvin (GF) were studied. The influence of the drug molecule on the film properties was also investigated. It was shown that film processing methodology employed has no effect on the drug crystallinity according to X-ray diffraction (XRD) and Raman spectroscopy. Differences in aggregation behavior of APIs in films were observed through SEM and NIR chemical imaging analysis. NPX exhibited the strongest aggregation compared to the other drugs. The aggregation had a direct effect on drug content uniformity in the film. Mechanical properties of the film were also affected depending on the drug-polymer interaction. Due to strong hydrogen bonding with the polymer, NPX exhibited an increase in Young's Modulus (YM) of approximately 200%, among other mechanical properties, compared to GF films. A synergistic effect between surfactant/polymer and drug/polymer interactions in the FNB film resulted in an increase of more than 600% in YM compared to the GF film. The enhancement in drug dissolution rate of films due to the large surface area and smaller drug particle size was also demonstrated. PMID:22178619

  6. Derivatization-free gel permeation chromatography elucidates enzymatic cellulose hydrolysis

    OpenAIRE

    Engel Philip; Hein Lea; Spiess Antje C

    2012-01-01

    Abstract Background The analysis of cellulose molecular weight distributions by gel permeation chromatography (GPC) is a powerful tool to obtain detailed information on enzymatic cellulose hydrolysis, supporting the development of economically viable biorefinery processes. Unfortunately, due to work and time consuming sample preparation, the measurement of cellulose molecular weight distributions has a limited applicability until now. Results In this work we present a new method to analyze ce...

  7. Cellulose Ester / Polyolefin Binary Blends : Rheology, Morphology and Impact Properties

    OpenAIRE

    Besson, François; Vanhille, Aurélie; Budtova, Tatiana

    2012-01-01

    Due to depletion of fossil resources and global environmental respect awareness, interest in biobased plastic materials is tremendously growing. Direct extraction of vegetal polymers like cellulose followed by a chemical modification to bring new properties is one of the paths to produce a bioplastic. Progressively replaced by oil-based polymers in the sixties, thermoplastic cellulose esters are now reconsidered for various materials applications. To improve mechanical weaknesses of cellulose...

  8. Hydroxypropyl Cellulose Based Non-Volatile Gel Polymer Electrolytes for Dye-Sensitized Solar Cell Applications using 1-methyl-3-propylimidazolium iodide ionic liquid

    Science.gov (United States)

    Khanmirzaei, Mohammad Hassan; Ramesh, S.; Ramesh, K.

    2015-12-01

    Gel polymer electrolytes using imidazolium based ionic liquids have attracted much attention in dye-sensitized solar cell applications. Hydroxypropyl cellulose (HPC), sodium iodide (NaI), 1-methyl-3-propylimidazolium iodide (MPII) as ionic liquid (IL), ethylene carbonate (EC) and propylene carbonate (PC) are used for preparation of non-volatile gel polymer electrolyte (GPE) system (HPC:EC:PC:NaI:MPII) for dye-sensitized solar cell (DSSC) applications. The highest ionic conductivity of 7.37 × 10-3 S cm-1 is achieved after introducing 100% of MPII with respect to the weight of HPC. Temperature-dependent ionic conductivity of gel polymer electrolytes is studied in this work. XRD patterns of gel polymer electrolytes are studied to confirm complexation between HPC polymer, NaI and MPII. Thermal behavior of the GPEs is studied using simultaneous thermal analyzer (STA) and differential scanning calorimetry (DSC). DSSCs are fabricated using gel polymer electrolytes and J-V centeracteristics of fabricated dye sensitized solar cells were analyzed. The gel polymer electrolyte with 100 wt.% of MPII ionic liquid shows the best performance and energy conversion efficiency of 5.79%, with short-circuit current density, open-circuit voltage and fill factor of 13.73 mA cm-2, 610 mV and 69.1%, respectively.

  9. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain

    OpenAIRE

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Abbott, James; Micklem, Chris N.; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S.; Kitney, Richard; Reeve, Benjamin

    2016-01-01

    Bacterial cellulose is a remarkable material that is malleable, biocompatible, and over 10-times stronger than plant-based cellulose. It is currently used to create materials for tissue engineering, medicine, defense, electronics, acoustics, and fabrics. We describe here a bacterial strain that is readily amenable to genetic engineering and produces high quantities of bacterial cellulose in low-cost media. To reprogram this organism for biotechnology applications, we created a set of genetic ...

  10. A facile route to prepare cellulose-based films.

    Science.gov (United States)

    Xu, Qin; Chen, Chen; Rosswurm, Katelyn; Yao, Tianming; Janaswamy, Srinivas

    2016-09-20

    Cellulose is the most abundant renewable and biodegradable material available in nature. Its insoluble character in water as well as common organic and inorganic liquids, however, curtails the wholesome utility. The continuous rise for biodegradable products based on cellulose coupled with its intrinsic ability to form a viable substitute for the petroleum-based materials necessitates the critical need for solubilizing the cellulose. Herein, we demonstrate the feasibility of ZnCl2 solutions, especially the 64-72% concentrations, to dissolve cellulose. FTIR results suggest that Zn(2+) ions promote Zn⋯O3H interactions, which in-turn weaken the intrinsic O3H⋯O5 hydrogen bonds that are responsible for strengthening the cellulose chains. Interestingly, Ca(2+) ions promote interactions among the Zn-cellulose chains leading to the formation of nano fibrils and yield gelling solutions. The tensile strength of the Ca(2+) added Zn-cellulose films increases by around 250% compared to the Zn-cellulose films. Overall, utilization of inorganic salt solutions to solubilize and crosslink cellulose is cost-effective, recyclable and certainly stands out tall among the other available systems. More importantly, the proposed protocol is simple and is a "green" process, and thus its large-scale adaptability is quite feasible. We strongly believe that the outcome opens up a new window of opportunities for cellulose in the biomedical, pharmaceutical, food and non-food applications. PMID:27261751

  11. Étude de marché pour le service Skeeble

    OpenAIRE

    Ben Sliman, Kevin; Ahr, Anthony

    2013-01-01

    L’entreprise xb83studio est une entreprise de développement d’applications qui a pour produit phare Skeeble. Ce service est un système de gestion de contenus. Il est accessible depuis internet. Il permet aux particuliers et aux entreprises de créer des applications pour Smartphone sous les systèmes d’exploitation Apple et Android. Il est convivial à utiliser et ne nécessite aucune connaissance particulière pour être utiliser. Monsieur Bertschy a pour objectif de vendre son service à environ 1...

  12. Extraction and characterization of cellulose nano whiskers from balsa wood

    International Nuclear Information System (INIS)

    In this study cellulose nano whiskers were obtained from balsa wood. For this purpose, fibers of balsa wood were subjected to hydrolysis reactions for lignin and hemi cellulose digestion and acquisition of nano-scale cellulose. Cellulose nano crystals obtained had medium length and thickness of 176 nm and 7 nm respectively. Infrared spectroscopy and x-ray diffraction showed that the process used for extracting nano whiskers could digest nearly all the lignin and hemi cellulose from the balsa fiber and still preserve the aspect ratio and crystallinity, satisfactory enough for future application in polymer nano composites. Thermogravimetry showed that the onset temperature of thermal degradation of cellulose nano crystals (226 degree C) was higher than the temperature of the balsa fiber (215 degree C), allowing its use in molding processes with many polymers from the molten state.(author)

  13. Effect of Surface Attachment on Synthesis of Bacterial Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R [ORNL; O' Neill, Hugh Michael [ORNL

    2005-01-01

    Gluconacetobacter spp. synthesize a pure form of hydrophilic cellulose that has several industrial specialty applications. Literature reports have concentrated on intensive investigation of static and agitated culture in liquid media containing high nutrient concentrations optimized for maximal cellulose production rates. The behavior of these bacteria on semisolid and solid surfaces has not been specifically addressed. The species Gluconacetobacter hansenii was examined for cellulose synthesis and colony morphology on a range of solid supports, including cotton linters, and on media thickened with agar, methyl cellulose, or gellan. The concentration and chemical structure of the thickening agent were found to be directly related to the formation of contiguous cellulose pellicules. Viability of the bacteria following freezer storage was improved when the bacteria were frozen in their cellulose pellicules.

  14. Investigations of biopolymer degradation in aqueous solutions with a view to applications in enhanced petroleum recovery. [Xanthane, sceleroglucane, hydroxyethyl cellulose]. Abbauuntersuchungen an Biopolymeren in waessriger Loesung mit besonderer Eignung fuer die tertiaere Erdoelgewinnung

    Energy Technology Data Exchange (ETDEWEB)

    Wehrhahn, A.-K.

    1986-07-03

    Flooding with aqueous polymer solutions is a well-established technique of enhanced petroleum recovery. Suitable polymers must have high viscosity for longer periods of time under deposit conditions. Viscosity losses are mostly the result of polymer degradation. In the investigation, degradation under deposit conditions was simulated by tempering at different temperatures and by irradiation. The three biopolymers xanthane, scleroglucane, and hydroxyethyl cellulose all three are discussed for future applications in polymer flooding.

  15. 0.25{mu}m radiation tolerant technology for space applications; Technology 0.25 {mu}m tolerante aux radiations pour les applications spatiales

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, N.; Brady, F.; Scott, T.; Yoder, J. [Lockheed Martin Federal Systems, Manassas, VA (United States)

    1999-07-01

    Lockheed Martin federal systems has developed a state-of-the-art radiation tolerant 0,25 {mu}m CMOS capability that is compatible with commercial foundries as well as radiation hardened fabrication. A technology test chip was designed, fabricated and evaluated for performance, power and radiation hardness in order to validate the methodology and evaluate the technology. Testing results show that -) the active transistor threshold shift is negligible for 0.25 {mu}m CMOS, -) the hardened STI (shallow trench isolation) can support Mega-rad applications, and -) the holding voltage is well beyond the operating voltage of 2.5 V. This technology is intended to support high density, high performance and low power space applications.

  16. Parallelization of applications for networks with homogeneous and heterogeneous processors; Parallelisation d`applications pour des reseaux de processeurs homogenes ou heterogenes

    Energy Technology Data Exchange (ETDEWEB)

    Colombet, L.

    1994-10-07

    The aim of this thesis is to study and develop efficient methods for parallelization of scientific applications on parallel computers with distributed memory. The first part presents two libraries of PVM (Parallel Virtual Machine) and MPI (Message Passing Interface) communication tools. They allow implementation of programs on most parallel machines, but also on heterogeneous computer networks. This chapter illustrates the problems faced when trying to evaluate performances of networks with heterogeneous processors. To evaluate such performances, the concepts of speed-up and efficiency have been modified and adapted to account for heterogeneity. The second part deals with a study of parallel application libraries such as ScaLAPACK and with the development of communication masking techniques. The general concept is based on communication anticipation, in particular by pipelining message sending operations. Experimental results on Cray T3D and IBM SP1 machines validates the theoretical studies performed on basic algorithms of the libraries discussed above. Two examples of scientific applications are given: the first is a model of young stars for astrophysics and the other is a model of photon trajectories in the Compton effect. (J.S.). 83 refs., 65 figs., 24 tabs.

  17. La gestation pour autrui

    OpenAIRE

    Delaisi de Parseval, Geneviève; Collard, Chantal

    2007-01-01

    La gestation pour autrui recouvre trois situations différentes les unes des autres et souvent confondues : dans le premier cas, la mère de substitution renonce à la naissance à ses droits parentaux sur un bébé qui a été conçu par insémination artificielle avec son ovocyte et le sperme du père d’intention après que ce dernier ait effectué une reconnaissance ante natale. Dans le second cas, une mère seule­ ment gestatrice porte un embryon conçu in vitro par les parents génétiques du bébé à qui ...

  18. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain

    Science.gov (United States)

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Micklem, Chris N.; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S.; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-01-01

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae. Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

  19. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain.

    Science.gov (United States)

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Abbott, James; Micklem, Chris N; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-06-14

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology. PMID:27247386

  20. Cellulose Synthesis and Its Regulation

    OpenAIRE

    Li, Shundai; Bashline, Logan; Lei, Lei; Gu, Ying

    2014-01-01

    Cellulose, the most abundant biopolymer synthesized on land, is made of linear chains of ß (1–4) linked D-glucose. As a major structural component of the cell wall, cellulose is important not only for industrial use but also for plant growth and development. Cellulose microfibrils are tethered by other cell wall polysaccharides such as hemicellulose, pectin, and lignin. In higher plants, cellulose is synthesized by plasma membrane-localized rosette cellulose synthase complexes. Despite the re...

  1. Une méthode pour estimer l’interception du rayonnement par un couvert bas : application au colza avant montaison

    Directory of Open Access Journals (Sweden)

    Denoroy Pascal

    2002-01-01

    Full Text Available Dans les modèles de simulation du fonctionnement des cultures, l’interception du rayonnement est une variable cruciale pour la prévision de la productivité en biomasse. D’autre part, la connaissance de l’interception du rayonnement par une culture permet de mieux analyser la réponse à un traitement en autorisant la distinction entre les effets morphogénétique et physiologique du traitement. Par exemple, dans l’étude de la fertilisation azotée du colza [1] on a pu faire la part de l’effet morphogénétique (accroissement de l’indice foliaire, donc de l’interception et de l’amélioration de la conversion photosynthétique du rayonnement absorbé. Dans un cas comme dans l’autre, une estimation correcte de l’interception du rayonnement est essentielle. Très souvent, un formalisme dérivé de la loi de Beer-Lambert est utilisé pour quantifier la part interceptée du rayonnement : PARi = epsiloni PAR (1 et epsiloni = 1 - e- k.IF (2, PAR représentant le rayonnement photosynthétiquement actif incident (exprimé en Joules ou en moles de photons, PARi la part de ce dernier interceptée par le couvert, epsiloni le coefficient (sans dimension d’interception, IF l’indice foliaire et k le coefficient d’extinction du rayonnement. Un formalisme un peu plus complexe doit être utilisé si on veut considérer le rayonnement absorbé [1, 2]. Pour des cultures couvrantes, la sensibilité de ces modèles à la valeur de k est faible pour les IF élevés, c’est pourquoi ces modèles sont souvent utilisés avec succès. Mais aux faibles IF, les modèles sont sensibles à k, d’où l’importance de l’estimation de ce paramètre pour les cultures présentant une longue période de faible couverture du sol, tel le colza peu fertilisé en phase hivernale. De plus, pour les cultures discontinues, c’est-à-dire présentant des zones où le sol n’est pas du tout couvert par la végétation, comme les inter-rangs, on doit

  2. Fulton Cellulosic Ethanol Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Sumait, Necy [BlueFire Ethanol, Irvine, CA (United States); Cuzens, John [BlueFire Ethanol, Irvine, CA (United States); Klann, Richard [BlueFire Ethanol, Irvine, CA (United States)

    2015-07-24

    Final report on work performed by BlueFire on the deployment of acid hydrolysis technology to convert cellulosic waste materials into renewable fuels, power and chemicals in a production facility to be located in Fulton, Mississippi.

  3. Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582

    OpenAIRE

    Michael Florea; Benjamin Reeve; James Abbott; Freemont, Paul S.; Tom Ellis

    2016-01-01

    Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in ...

  4. Production and Characterization of Highly Thermostable β-Glucosidase during the Biodegradation of Methyl Cellulose by Fusarium oxysporum

    OpenAIRE

    Folasade M. Olajuyigbe; Nlekerem, Chidinma M.; Ogunyewo, Olusola A.

    2016-01-01

    Production of β-glucosidase from Fusarium oxysporum was investigated during degradation of some cellulosic substrates (Avicel, α-cellulose, carboxymethyl cellulose (CMC), and methylcellulose). Optimized production of β-glucosidase using the cellulosic substrate that supported highest yield of enzyme was examined over 192 h fermentation period and varied pH of 3.0–11.0. The β-glucosidase produced was characterized for its suitability for industrial application. Methyl cellulose supported the h...

  5. High Performance Regenerated Cellulose Membranes from Trimethylsilyl Cellulose

    KAUST Repository

    Ali, Ola

    2013-05-01

    Regenerated cellulose (RC) membranes are extensively used in medical and pharmaceutical separation processes due to their biocompatibility, low fouling tendency and solvent resistant properties. They typically possess ultrafiltration and microfiltration separation characteristics, but recently, there have been attempts to widen their pool of applications in nanofiltration processes. In this work, a novel method for preparing high performance composite RC membranes was developed. These membranes reveal molecular weight cut-offs (MWCO) of less than 250 daltons, which possibly put them ahead of all commercial RC membranes and in competition with high performance nanofiltration membranes. The membranes were prepared by acidic hydrolysis of dip-coated trimethylsilyl cellulose (TMSC) films. TMSC, with a degree of silylation (DS) of 2.8, was prepared from microcrystalline cellulose by reaction with hexamethyldisilazane under the homogeneous conditions of LiCl/DMAC solvent system. Effects of parameters, such as coating solution concentration and drying rates, were investigated. It was concluded that higher TMSC concentrations as well as higher solvent evaporation rates favor better MWCOs, mainly due to increase in the selective layer thickness. Successful cross-linking of prepared membranes with glyoxal solutions, in the presence of boric acid as a catalyst, resulted in MWCOs less than 250 daltons. The suitability of this crosslinking reaction for large scale productions was already proven in the manufacturing of durable-press fabrics. For us, the inexpensive raw materials as well as the low reaction times and temperatures were of interest. Moreover, the non-toxic nature of glyoxal is a key advantage in medical and pharmaceutical applications. The membranes prepared in this work are strong candidates for separation of small organic solutes from organic solvents streams in pharmaceutical industries. Their hydrophilicity, compared to typical nanofiltration membranes, offer

  6. Growth and characterization of single-crystal CVD diamond for radiation detection applications; Synthese et caracterisation de diamants monocristallins pour applications de detecteur de rayonnements

    Energy Technology Data Exchange (ETDEWEB)

    Tranchant, N

    2008-01-15

    This work aimed at the study of the synthesis of single crystal diamond using the Microwave enhanced Chemical Vapour Deposition technique (MPCVD). The work enabled the development and optimisation of the growth conditions, from the study of the crystalline quality, of the material purity, and of its electronic properties. The assessment of the transport properties was the most determinant: the use of the time of flight (TOF) technique has enabled the measurement of the carrier mobilities and of their kinetic properties as a function of the temperature. When coupled with collected charge efficiency measurements, the work led to remarkable carrier mobility values obtained in the synthesised crystals (3000 cm{sup 2}.V-1.s{sup -1}). Prepared samples were mounted as detection devices and used successfully in real conditions for the monitoring of ultra-fast pulses, as well as for neutron fluency monitoring, and for medical dosimeters for radiotherapy applications. (author)

  7. Modification of bacterial cellulose through exposure to the rotating magnetic field.

    Science.gov (United States)

    Fijałkowski, Karol; Żywicka, Anna; Drozd, Radosław; Niemczyk, Agata; Junka, Adam Feliks; Peitler, Dorota; Kordas, Marian; Konopacki, Maciej; Szymczyk, Patrycja; Fray, Mirosława El; Rakoczy, Rafał

    2015-11-20

    The aim of the study was to assess the influence of rotating magnetic field (RMF) on production rate and quality parameters of bacterial cellulose synthetized by Glucanacetobacter xylinus. Bacterial cultures were exposed to RMF (frequency f=50Hz, magnetic induction B=34mT) for 72h at 28°C. The study revealed that cellulose obtained under RMF influence displayed higher water absorption, lower density and less interassociated microfibrils comparing to unexposed control. The application of RMF significantly increased the amount of obtained wet cellulose pellicles but decreased the weight and thickness of dry cellulose. Summarizing, the exposure of cellulose-synthesizing G. xylinus to RMF alters cellulose biogenesis and may offer a new biotechnological tool to control this process. As RMF-modified cellulose displays better absorbing properties comparing to non-modified cellulose, our finding, if developed, may find application in the production of dressings for highly exudative wounds. PMID:26344254

  8. Elaboration d'un composite conducteur a base de polypyrrole et de nanofibres de cellulose

    Science.gov (United States)

    Bideau, Benoit

    Le projet de production de nanocellulose à grande échelle par l'équipe de recherche du professeur Claude Daneault, ne pourra se faire sans avoir démontré sa quelconque utilité sur le marché économique. C'est dans cette optique que s'est articulé mon travail afin de mettre en avant une des voix de valorisation de ces nanocelluloses. Nous avons travaillé plus précisément sur le développement d'un nanocomposite conducteur biodégradable. Nous nous sommes proposé dans ce travail de développer une technique simple et écologique permettant la conception d'un matériau composite conducteur. Nous avons étudié l'influence des nanofibres de cellulose, du pyrrole, de la température, de la durée de polymérisation et l'ajout d'additifs dans le matériau composite. L'étude de ces paramètres nous a permis de déterminer les meilleures conditions pour le développement d'un film composite conducteur avec des propriétés mécaniques acceptables. L'ajout de ce renfort (nanofibres), au sein de la matrice de polypyrrole a permis d'obtenir des films intéressants, de part leurs propriétés mécaniques, électriques et de leur caractère biodégradable. Des comparaisons ont été effectuées avec des fibres oxydées, afin d'étudier l'apport des nanofibres de cellulose au composite. Notre étude a ensuite été élargie à l'ajout d'additifs dans les matériaux conducteurs afin d'améliorer certaines propriétés du composite. L'objectif de ce travail visait l'étude de l'incorporation des nanofibres de cellulose dans une matrice de polypyrrole en vue de son utilisation en tant que matériau conducteur biodégradable pour des applications dans le domaine énergétique. Mots Clés: Nanocellulose, polypyrrole, composite, conducteur, biodégradable, propriétés mécaniques, additifs.

  9. Characterization of Bacterial Cellulose by Gluconacetobacter hansenii CGMCC 3917.

    Science.gov (United States)

    Feng, Xianchao; Ullah, Niamat; Wang, Xuejiao; Sun, Xuchun; Li, Chenyi; Bai, Yun; Chen, Lin; Li, Zhixi

    2015-10-01

    In this study, comprehensive characterization and drying methods on properties of bacterial cellulose were analyzed. Bacterial cellulose was prepared by Gluconacetobacter hansenii CGMCC 3917, which was mutated by high hydrostatic pressure (HHP) treatment. Bacterial cellulose is mainly comprised of cellulose Iα with high crystallinity and purity. High-water holding and absorption capacity were examined by reticulated structure. Thermogravimetric analysis showed high thermal stability. High tensile strength and Young's modulus indicated its mechanical properties. The rheological analysis showed that bacterial cellulose had good consistency and viscosity. These results indicated that bacterial cellulose is a potential food additive and also could be used for a food packaging material. The high textural stability during freeze-thaw cycles makes bacterial cellulose an effective additive for frozen food products. In addition, the properties of bacterial cellulose can be affected by drying methods. Our results suggest that the bacterial cellulose produced from HHP-mutant strain has an effective characterization, which can be used for a wide range of applications in food industry. PMID:26352877

  10. Study of Nano-fiber Cellulose Production by Glucanacetobacter xylinum ATCC 10245

    OpenAIRE

    A. Akbarzadeh; Farahnak, M.; Ghassemi, S.; Chiani, M.; Mehrabi, M. R.; Saffari, Z.; Tolooei, S.; Farhangi, A.; Norouzian, D.

    2011-01-01

    Bacterial Celluloses (BC) are gaining importance in research and commerce due to numerous factors affecting the bacterial cellulose characteristics and application in different industries. The aim of the present study was to produce bacterial cellulose in different media using different cultivation vessels. Bacterial cellulose was produced by static cultivation of Glucanacetobacter xylinum ATCC 10245 in different culture media such as Brain Heart Agar, Luria Bertani Agar /Broth, Brain Heart I...

  11. Study of nano-fiber cellulose production by Glucanacetobacter xylinum ATCC 10245.

    OpenAIRE

    Norouzian, D.; Farhangi, Ali; Tolooei, S.; Saffari, Z.; Mehrabi, M. R.; Chiani, M.; Ghassemi, S.; Farahnak, M.; Akbarzadeh, Azim

    2011-01-01

    International audience Bacterial Celluloses (BC) are gaining importance in research and commerce due to numerous factors affecting the bacterial cellulose characteristics and application in different industries. The aim of the present study was to produce bacterial cellulose in different media using different cultivation vessels. Bacterial cellulose was produced by static cultivation of Glucanacetobacter xylinum ATCC 10245 in different culture media such as Brain Heart Agar, Luria Bertani ...

  12. Croissance localisée par transport VLS de carbure de silicium sur substrats SiC et diamant pour des applications en électronique de puissance

    OpenAIRE

    Vo-Ha, Arthur,

    2014-01-01

    La croissance localisée de SiC dopé p par un mécanisme Vapeur-Liquide-Solide (VLS) a été effectuée sur substrats SiC-4H (0001) 8°off et diamant (100). Pour ce faire, des motifs constitués d'un empilement silicium-aluminium sont fondus puis alimentés en propane. Dans le cas de l'homoépitaxie de SiC-4H, il a été démontré que la quantité limitée de phase liquide initiale entraine une évolution constante des paramètres de croissance en raison de l'appauvrissement graduel en silicium. Il est toute...

  13. Une approche non linéaire pour la reconnaissance des formes statistique: application à la céphalométrie

    OpenAIRE

    Romaniuk, Barbara; Desvignes, Michel; Robiaille, Julien; Revenu, Marinette; Deshayes, Marie-Josèphe

    2002-01-01

    Dans cet article, nous comparons deux approches, l'une linéaire, l'autre non linéaire, pour la localisation statistique de points caractéristiques sur des images 2D. Un modèle statistique est construit à partir d'un ensemble d'images expertisées, nécessitant un recalage entre images. Le recalage rigide est la solution linéaire classique, que nous comparons à une solution non linéaire : elle consiste à projeter les coordonnées des points expertisés dans un espace de dimension supérieure et à r...

  14. Synthèse et caractérisation de nouveaux matériaux organophosphorés pour des applications en optoélectronique

    OpenAIRE

    Delaunay, Wylliam

    2013-01-01

    Ce manuscrit décrit la synthèse et la caractérisation de nouvelles molécules incluant un cœur organophosphoré, le phosphole. Certaines de ces molécules ont été utilisées pour la fabrication de dispositifs OLEDs ou de cellules photovoltaïques organiques. Le premier chapitre fait un état de l'art de la chimie du phosphole dans le domaine des matériaux organiques entre 2010 et 2013. Le second chapitre décrit la synthèse et l'étude physico-chimique de molécules qui permettent de moduler l'angle d...

  15. Application de la chimie radicalaire des xanthates pour la synthèse de molécules organo-fluorées

    OpenAIRE

    Salomon, Pierre

    2014-01-01

    Les travaux menés au laboratoire depuis plusieurs années ont permis d'élaborer une méthode de construction de liaison carbone-carbone et carbone-hétéroélément particulièrement efficace. Son principe repose sur des additions radicalaires intermoléculaires entre un xanthate et une oléfine. La maîtrise de telles réactions a permis l'émergence de nouvelles stratégies de synthèses. Entre autre, cette méthode s'avère particulièrement efficace pour l'insertion de groupes fluorés, de grande importanc...

  16. Capteur de courants innovant pour des systèmes polyphasés - Application aux câbles multiconducteurs

    OpenAIRE

    Bourkeb, Menad,

    2014-01-01

    International audience Cette article porte sur l'étude et la réalisation d'un prototype de capteur de courants innovant pour des câbles multiconducteurs. Outre le caractère non-intrusif de ce capteur (i.e. mesure sans contact), il permet de réaliser une mesure sur un système polyphasé dont la position des conducteurs est inconnue. L'approche adoptée est basée sur la résolution d'un problème inverse. En effet, à partir d'une mesure de la signature des champs magnétiques autour du câble mult...

  17. Une approche par formalisme de green réduit pour le calcul des structures en contact dynamique : application au contact pneumatique/chaussée

    OpenAIRE

    Meftah, Rabie

    2011-01-01

    Le travail de cette thèse s'inscrit dans le cadre de la réduction du bruit du traffic routier. Le contact pneumatique/chaussée représente la principale source de ce phénomène dès la vitesse de 50 km/h. Dans ce contexte, une nouvelle démarche de modélisation du comportement dynamique d'un pneumatique roulant sur une chaussée rigide est développée. Au niveau du pneumatique, un modèle périodique est adopté pour calculer les fonctions de Green du pneumatique dans la zone de contact. Ce modèle per...

  18. Etude pour quantifier la part des apports internes dans bâtiment tertiaire BBC. Application au bâtiment de PREDIS

    OpenAIRE

    Chenailler, Hervé; Wurtz, Frédéric; Ploix, Stéphane; Joussellin, Florence; Bontemps, André

    2010-01-01

    La conception de bâtiments a longtemps été réduite à la conception de leurs enveloppes, reléguant ainsi la représentation des usages à des courbes d'apports internes gratuits. Or, la recherche de meilleures performances en termes d'efficacité énergétique, qui se traduit par le rapport entre les besoins en énergie non gratuite sur le confort pour les occupants, pose le problème de conception en des termes nouveaux. Il s'agit dès lors de vérifier que l'énergie consommée correspond bien à un bes...

  19. CRIQUE : Un modèle pour classer des événements : Application en sécurité routière

    OpenAIRE

    Aron, Maurice; SEIDOWSKY, Régine; TENDJAOUI, Mustapha

    2004-01-01

    Le diagnostic constitue la première étape du traitement d'événements ; pour certains types d'événements - rares, de nature complexe - une classification préalable est utile. Dans le cas où toutes les données ne peuvent être informatisées, il faut prendre en compte les connaissances de l'utilisateur dans la classification informatique. C'est ce que propose le système CRIQUE (Classement à partir de règles, de données informatisées et de questions), qui allie des méthodes d'intelligence artifici...

  20. Interaction sensori-motrice en robotique : application à la préhension automatisée pour une main articulée à plusieurs doigts

    OpenAIRE

    Bard, Christian

    1994-01-01

    Planifier des opérations de saisie robustes, impliquant une main articulée robotique et un objet place dans un environnement tridimensionnel, met en jeu deux types de problèmes: le choix d'une stratégie de saisie (preconfiguration de la main, paramétrés de saisie, type de mouvement a exécuter) et l'analyse des interactions physiques main/objet. Le premier probleme repose sur l'analyse de critères géométriques et des contraintes de tache. L'étude du deuxième probleme a pour objet de conclure s...

  1. Genome sequence and plasmid transformation of the model high-yield bacterial cellulose producer Gluconacetobacter hansenii ATCC 53582

    Science.gov (United States)

    Florea, Michael; Reeve, Benjamin; Abbott, James; Freemont, Paul S.; Ellis, Tom

    2016-03-01

    Bacterial cellulose is a strong, highly pure form of cellulose that is used in a range of applications in industry, consumer goods and medicine. Gluconacetobacter hansenii ATCC 53582 is one of the highest reported bacterial cellulose producing strains and has been used as a model organism in numerous studies of bacterial cellulose production and studies aiming to increased cellulose productivity. Here we present a high-quality draft genome sequence for G. hansenii ATCC 53582 and find that in addition to the previously described cellulose synthase operon, ATCC 53582 contains two additional cellulose synthase operons and several previously undescribed genes associated with cellulose production. In parallel, we also develop optimized protocols and identify plasmid backbones suitable for transformation of ATCC 53582, albeit with low efficiencies. Together, these results provide important information for further studies into cellulose synthesis and for future studies aiming to genetically engineer G. hansenii ATCC 53582 for increased cellulose productivity.

  2. Dispersion of SiC nanoparticles in cellulose for study of tensile, thermal and oxygen barrier properties.

    Science.gov (United States)

    Kisku, Sudhir K; Dash, Satyabrata; Swain, Sarat K

    2014-01-01

    Cellulose/silicon carbide (cellulose/SiC) nanobiocomposites were prepared by solution technique. The interaction of SiC nanoparticles with cellulose were confirmed by Fourier transformed infrared (FTIR) spectroscopy. The structure of cellulose/SiC nanobiocomposites was investigated by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The tensile properties of the nanobiocomposites were improved as compared with virgin cellulose. Thermal stabilities of cellulose/SiC nanobiocomposites were studied by thermogravimetric analysis (TGA). The cellulose/SiC nanobiocomposites were thermally more stable than the raw cellulose. It may be due to the delamination of SiC with cellulose matrix. The oxygen barrier properties of cellulose composites were measured using gas permeameter. A substantial reduction in oxygen permeability was obtained with increase in silicon carbide concentrations. The thermally resistant and oxygen barrier properties of the prepared nanobiocomposites may enable the materials for the packaging applications. PMID:24274511

  3. Synthesis and properties of cellulose functionalized -4, 4'-(propane-2, 2'-diyl) diphenol-SiO2/TiO2 hybrid nanocomposites materials for high performance applications

    Science.gov (United States)

    Ramesh, Sivalingam; Kim, Gwang-Hoon; Kim, Heung-Soo; Kim, Jaehwan; Kim, Joo-Hyung

    2013-04-01

    The general class of organic-inorganic hybrid nanocomposites materials is a fast growing area of research. The significant effort is focused on the ability to control the nanoscale structures via organic functional synthetic approaches with inorganic metal oxides. The properties of nanocomposites material depends on the properties of their individual components but also their morphological and interfacial characteristics. This rapidly expanding field is generating many exciting new materials with novel properties. Mainly, cellulose is considered as the richest renewable materials are presently among the most promising candidates for use in photonics due to their versatility, flexibility, light weight, low cost and ease of modification. Cellulose-metal oxide nanomaterials were developed the technologies to manipulate selfassembly and multifunctionallity, of new technologies to the point where industry can produce advanced and costcompetitive cellulose metal oxide hybrid materials. Therefore, the present study is focused on cellulose-functionalized - 4, 4'-(propane-2, 2'-diyl) diphenol-SiO2/TiO2 hybrid nano-composites materials by in-situ sol-gel process. The chemical and morphological properties of cellulose-functionalized SiO2/TiO2 materials via covalent crosslinking hybrids were characterized by FTIR, XRD, TGA, DSC, SEM, TEM and optical properties.

  4. Application of Molecular Techniques to Elucidate the Influence of Cellulosic Waste on the Bacterial Community Structure at a Simulated Low-Level-Radioactive-Waste Site

    International Nuclear Information System (INIS)

    Low-level radioactive waste sites, including those at various U.S. Department of Energy (DOE) sites, frequently contain cellulosic waste in the form of paper towels, cardboard boxes, or wood contaminated with heavy metals and radionuclides such as chromium and uranium. To understand how the soil microbial community is influenced by the presence of cellulosic waste products, multiple soil samples were obtained from a non-radioactive model low-level waste test pit at the Idaho National Laboratory. Samples were analyzed using 16S rDNA clone libraries and 16S rRNA gene microarray (PhyloChip) analyses. Both the clone library and PhyloChip results revealed changes in the bacterial community structure with depth. In all samples, the PhyloChip detected significantly more unique Operational Taxonomic Units (OTUs), and therefore more relative diversity, than the clone libraries. Calculated diversity indices suggest that diversity is lowest in the Fill (F) and Fill Waste (FW) layers and greater in the Wood Waste (WW) and Waste Clay (WC) layers. Principal coordinates analysis and lineage specific analysis determined that Bacteroidetes and Actinobacteria phyla account for most of the significant differences observed between the layers. The decreased diversity in the FW layer and increased members of families containing known cellulose degrading microorganisms suggests the FW layer is an enrichment environment for cellulose degradation. Overall, these results suggest that the presence of the cellulosic material significantly influences the bacterial community structure in a stratified soil system.

  5. Micro reactor for heterogeneous catalysis / application: hydrogen storage from methyl-cyclohexane; Microreacteur pour la catalyse heterogene / application au stockage d'hydrogene a partir du methylcyclohexane

    Energy Technology Data Exchange (ETDEWEB)

    Roumanie, M.; Pijolat, C. [Ecole Nationale Superieure des Mines, Centre SPIN, Dept. MICC, LPMG-URA CNRS D2021, 42 - Saint-Etienne (France); Meille, V.; Bellefon, C. de [CNRS - CPE, Lab. de Genie des Procedes Catalytiques, 69 - Villeurbanne (France); Pouteau, P.; Delattre, C. [CEA Grenoble, Lab. d' Electronique et de Technologie de l' Intrumentation, LETI, 38 (France)

    2005-07-01

    The use of micro-technology and the miniaturization of various systems such as micro-fuel cell is a current field of activity. The aim of this work is to study and to realize an autonomous catalytic micro-reactor for hydrogen release from methyl-cyclohexane. For this reaction of dehydrogenation, the common catalyst is platinum supported on alumina. Consequently, the general objectives of this work are: (i)to develop a micro-reactor with its heaters, sensors..., (ii)to deposit catalysts in the micro-reactor, and (iii)to study the catalytic conversion of this system. The chip used has been developed by the CEA-LETI for biomedical application especially DNA chip. It is comprising several channels etched in silicon substrate with a classic deep reactive ion etching process. These channels of 100 {mu}m depth are structured with pillars to increase the surface and thus improve the overall reaction rate compare to a channel without pillar. The structured micro-reactor is molecularly bonded with a silicon cover to form an airtight devices. As the silicon is transparent to the infrared wavelength a CCD camera is used to observe the bonding quality. The chips are then connected with micro-tubes to test them. The first tested solution consists in a polyimide-glass capillary of 100 {mu}m OD and 40 {mu}m ID stuck inside the channel entrance and glued with a ceramic cement or glass. A second solution is currently under development with metallic capillaries. The reaction studied is extremely endothermic with a heat of reaction of 204 kJ/mol. Consequently it is necessary to include in this system some heaters to have an autonomous micro-reactor. Thick film resistances of platinum have been deposited by the screen printing and used as micro-heaters. The tests of micro-heaters are realized using the infrared thermographic camera. As the silicon is transparent to infrared wavelength, a sputtered platinum layer has been deposited on the opposite face of the resistances. This layer

  6. Émulsions stabilisées par des particules solides: études physico-chimiques et évaluation pour l'application cutanée.

    OpenAIRE

    Frelichowska, Justyna

    2009-01-01

    La stabilisation des émulsions peut être assurée par des particules solides plutôt qu'avec des molécules d'émulsifiant. Les émulsions stabilisées par des particules solides sont aussi appelées “les émulsions de Pickering”. Ce travail est divisé en deux parties : 1) l'étude des aspects physico-chimiques des émulsions ; 2) l'évaluation des émulsions stabilisées par des solides pour l'application cutanée. Les émulsions ont été stabilisées avec des nanoparticules de silice de caractère hydrophobe...

  7. Développement de capteurs optimisés pour l'IRM à champ magnétique faible (0.2T) : application à l'imagerie de l'animal

    OpenAIRE

    Feuillet, Thomas

    2014-01-01

    L'imagerie par résonance magnétique (IRM) appliquée au domaine vétérinaire exploite des systèmes à bas champ magnétostatique qui ont de nombreux avantages, notamment leur faible coût d'achat et d'entretien. Mais sur ces machines, les capteurs radiofréquence (RF) sont initialement dédiées à l'homme et ne permettent pas une qualité d'image optimale. Dans le cadre de cette thèse, des méthodes simples d'optimisation de capteurs à 0,2 T ont été développées, puis exploitées pour des applications de...

  8. Antioxidant films based on cross-linked methyl cellulose and native Chilean berry for food packaging applications.

    Science.gov (United States)

    López de Dicastillo, Carol; Rodríguez, Francisco; Guarda, Abel; Galotto, Maria José

    2016-01-20

    Development of antioxidant and antimicrobial active food packaging materials based on biodegradable polymer and natural plant extracts has numerous advantages as reduction of synthetic additives into the food, reduction of plastic waste, and food protection against microorganisms and oxidation reactions. In this way, active films based on methylcellulose (MC) and maqui (Aristotelia chilensis) berry fruit extract, as a source of antioxidants agents, were studied. On the other hand, due to the high water affinity of MC, this polymer was firstly cross-linked with glutaraldehyde (GA) at different concentrations. The results showed that the addition of GA decreased water solubility, swelling, water vapor permeability of MC films, and the release of antioxidant substances from the active materials increased with the concentration of GA. Natural extract and active cross-linked films were characterized in order to obtain the optimal formulation with the highest antioxidant activity and the best physical properties for latter active food packaging application. PMID:26572446

  9. Photoresponsive Cellulose Nanocrystals

    Directory of Open Access Journals (Sweden)

    Dimitris S Argyropoulos

    2011-07-01

    Full Text Available In this communication a method for the creation of fluorescent cellulose nanoparticles using click chemistry and subsequent photodimerization of the installed side‐ chains is demonstrated. In the first step, the primary hydroxyl groups on the surface of the CNCs were converted to carboxylic acids by using TEMPO‐mediated hypohalite oxidation. The alkyne groups, essential for the click reaction, were introduced into the surface of TEMPO‐ oxidized CNCs via carbodiimide‐mediated formation of an amide linkage between monomers carrying an amine functionality and carboxylic acid groups on the surface of the TEMPO‐oxidized CNCs. Finally, the reaction of surface‐modified TEMPO‐oxidized cellulose nanocrystals and azido‐bearing coumarin and anthracene monomers were carried out by means of a click chemistry, i.e., Copper(I‐catalyzed Azide‐Alkyne Cycloaddition (CuAAC to produce highly photo‐responsive and fluorescent cellulose nanoparticles. Most significantly, the installed coumarin and/or anthracene side‐chains were shown to undergo UV‐induced [2+2] and [4+4] cycloaddition reactions, bringing and locking the cellulose nanocrystals together. This effort paves the way towards creating, cellulosic photo responsive nano‐arrays with the potential of photo reversibility since these reactions are known to be reversible at varying wavelengths.

  10. HPMC reinforced with different cellulose nanoparticles

    Science.gov (United States)

    Synthetic polymers, made almost entirely from chemicals derived from crude oil, are widely used as primary packaging in the food industry causing environmental issues. Hydroxypropyl Methyl Cellulose (HPMC) can be used as bio-based packaging material. In this study, the application of nanotechnology ...

  11. Biocompatibility of Bacterial Cellulose Based Biomaterials

    Directory of Open Access Journals (Sweden)

    Omar P. Troncoso

    2012-12-01

    Full Text Available Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received much attention, because of the possibility of combining the good properties of BC with other materials for specific applications. BC nanocomposites can be processed either in a static or an agitated medium. The fabrication of BC nanocomposites in static media can be carried out while keeping the original mat structure obtained after the synthesis to form the final nanocomposite or by altering the culture media with other components. The present article reviews the issue of biocompatibility of BC and BC nanocomposites. Biomedical aspects, such as surface modification for improving cell adhesion, in vitro and in vivo studies are given along with details concerning the physics of network formation and the changes that occur in the cellulose networks due to the presence of a second phase. The relevance of biocompatibility studies for the development of BC-based materials in bone, skin and cardiovascular tissue engineering is also discussed.

  12. POLYETHERSULFONE COMPOSITE MEMBRANE BLENDED WITH CELLULOSE FIBRILS

    Directory of Open Access Journals (Sweden)

    Ping Qu

    2010-09-01

    Full Text Available Polyethersulfone (PES is a common material used for ultrafiltration (UF membranes, which has good chemical resistance, high mechanical properties, and wide temperature tolerances. The hydrophobic property of the PES membrane seriously limits its application. Cellulose fibrils are composed of micro-sized and nano-sized elements, which have high hydrophilicity, strength, and biodegradation. A composite membrane was prepared by the phase inversion induced by an immersion process. The characteristics of the composite membrane were investigated with Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, thermogravimetric analysis (TGA, and atomic force microscopy (AFM. The pure water flux of the composite membrane increased dramatically with the increase of cellulose firbils. Mean pore size and porosity were significantly increased. Both mechanical properties and hydrophilicity were enhanced due to the addition of the cellulose firbils.

  13. In-situ polymerized cellulose nanocrystals (CNC)-poly(l-lactide) (PLLA) nanomaterials and applications in nanocomposite processing.

    Science.gov (United States)

    Miao, Chuanwei; Hamad, Wadood Y

    2016-11-20

    CNC-PLLA nanomaterials were synthesized via in-situ ring-opening polymerization of l-lactide in the presence of CNC, resulting in hydrophobic, homogeneous mixture of PLLA-grafted-CNC and free PLLA homopolymer. The free PLLA serves two useful functions: as barrier to further prevent PLLA-g-CNC from forming aggregates, and in creating improved interfacial properties when these nanomaterials are blended with other polymers, hence enhancing their performance. CNC-PLLA nanomaterials can be used for medical or engineering applications as-they-are or by compounding with suitable biopolymers using versatile techniques, such as solution casting, co-extrusion or injection molding, to form hybrid nanocomposites of tunable mechanical properties. When compounded with commercial-grade PLA, the resulting CNC-PLA nanocomposites appear transparent and have tailored (dynamic and static) mechanical and barrier properties, approaching those of poly(ethylene terephthalate), PET. The effect of reaction conditions on the properties of CNC-PLLA nanomaterials have been carefully studied and detailed throughout the paper. PMID:27561528

  14. 双线隧道仰拱整体式浇筑台车的研制及应用%Overall Pouring Trolley Development for Inverted Arch of Double-track Railway and Its Application

    Institute of Scientific and Technical Information of China (English)

    莫立胜

    2015-01-01

    分析了国内铁路隧道仰拱施工技术与设备存在的问题,针对铁路仰拱施工提出的新要求,介绍了云桂线高速铁路液压系统控制双线隧道仰拱整体式浇筑台车的研制及应用,并形成相应的施工工艺。采用自主研发的液压系统控制仰拱整体式浇筑台车,既能控制仰拱结构尺寸和弧线形状,大大改善了仰拱弧形段的施工质量,又做到了内实外美。通过在云桂线铁路革朗隧道中的施工应用实践证明,液压系统控制仰拱整体式浇筑台车在实际操作中切实可行,能有效加快施工进度,提高仰拱施工质量,具有广泛的推广应用价值。%The paper analyzes the problems on inverted arch construction technology and equipment in domestic railway tunnel.In connection with the new requirements of railway inverted arch construction,the development for inverted arch o-verall pouring trolley of double-track railway and its application with hydraulic pressure control system of Nanning-Kunming High-speed Railway are introduced,then the related construction technology is formed.By adopting the self-developed hy-draulic pressure system to control inverted arch overall pouring trolley,the size of inverted arch structure and arc shape can be controlled with great improvement of construction quality of the inverted arch arc segment,and then the internal fullness and external beauty can be achieved.Through the construction practice of Gelang Tunnel in Nanning-Kunming High-speed Railway,it proves that inverted arch overall pouring trolley with hydraulic pressure control system is feasible in practice. Therefore,the construction schedule is effectively speeded up,the construction quality of inverted arch is improved.It has a broad popularized value.

  15. Electrochemical synthesis of cellulose mesylate

    Science.gov (United States)

    Khidirov, Sh Sh; Akhmedov, M. A.; Khibiev, H. S.

    2016-04-01

    The article deal with the possibility anode modification of cellulose to form its ester - mesylate by voltametric measurement method and preparative electrosynthesis on a platinum electrode in the system cellulose - dimethyl sulfoxide - methanesulfonic

  16. Un environnement graphique pour le langage SIGNAL

    OpenAIRE

    Bournai, Patricia; Le Guernic, Paul

    1993-01-01

    Ce rapport présente un environnement de programmation polymorphe pour la conception d'applications temps réel décrites dans le langage Signal. Cet environnement offre à l'utilisateur des représentations graphiques et textuelles des structures du langage. Ces représentations peuvent être conjointement utilisées lors de la construction ou la "lecture" du programme, l'utilisateur dispose de formes adaptables à un niveau d'observation. Une expression Signal peut être considérée comme un ensemble ...

  17. Structure of cellulose acetobacter xylinum

    International Nuclear Information System (INIS)

    The data are presented on optimization of cellulose synthesis by Acetobacter xylinum (strain VKM V-880) and the structural characteristics of A. xylinum cellulose gel film synthesized during static cultivation. The structural changes caused by the removal of water from gel films are established and the structural organization of macromolecular chains in cellulose A. xylinum is studied

  18. Basic Characteristics and Application of Bacterial Cellulose%细菌纤维素的基本特性与其应用

    Institute of Scientific and Technical Information of China (English)

    黄莉; 王英男; 夏秀芳; 丁一; 杨明; 王松

    2013-01-01

    细菌纤维素是由微生物发酵合成的天然无毒的纳米材料。能够合成细菌纤维素的微生物共有8种,这8种微生物可通过静态发酵和动态发酵两种方式产生细菌纤维素。因为细菌纤维素具有高纯度、高结晶度、精细的网络结构、生物适应性和可降解性等特性,所以在食品及其包装行业、医药保健品业、以及造纸工业中得到了广泛的应用。%Bacterial cellulose is a kind of natural and nontoxic nanomaterials that is synthetized by micro -bial fermentation .There are eight types of micro-organisms that can produce bacterial cellulose , they can pro-duce bacterial cellulose through two ways that the static the fermentation and dynamic fermentation .Bacterial cellulose with high purity , crystallinity , the fine structure of the network , biocompatibility and biodegradability properties, so it has widely used in the food packaging industry , medicine and health products industry , as well as the paper industry .

  19. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes.

    Science.gov (United States)

    Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M

    2016-02-23

    Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-film-immobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases. PMID:26799780

  20. Degradation of cellulose in irradiated wood and purified celluloses

    International Nuclear Information System (INIS)

    The degradation of cellulose chains in Pinus radiata and Eucalyptus regnans given small gamma-radiation doses has been studied. Scission yields showed marked dose-dependency effects, of which some appear to be due to an inherent dose-dependency exhibited by cellulose itself, and others indicate a protective action of some natural wood constituents. A uniform treatment of viscometry data reported by various workers who have studied radiation-induced degradation of purified cellulose materials, has been used to enable their scission results to be compared with each other and with those for natural wood cellulose of various dose levels. Generally, cellulose in wood is less degraded by radiation than is purified cellulose. However, with Eucalyptus regnans remarkably high scission yields, significantly higher than expected for purified cellulose, were observed at dose levels of 0.5-1.0 x 104Gy. The relevance of these results to changes in pulp yield following irradiation of wood chips, is briefly discussed. (author)

  1. The cellulose resource matrix

    NARCIS (Netherlands)

    Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G.

    2013-01-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where

  2. Cysticercosis cellulose cutis

    Directory of Open Access Journals (Sweden)

    Inamadar Arun

    2001-01-01

    Full Text Available A woman aged 30 years with solitary lesion of cysticercosis cellulose cutis is reported. Cutaneous cysticerci are often a pointer to the involvement of internal organs. Our patient was a pure vegetarian so, probable mode of infection may be ingestion of contaminated vegetables, where the practice of using pig feces as manure is prevalent.

  3. Derivatives of Oxidized Cellulose

    Czech Academy of Sciences Publication Activity Database

    Taubner, T.; Sobek, Jiří; Havelka, P.; Kvasnička, F.; Synytsya, A.; Čopíková, J.

    Praha : Česká společnost chemická, 2009, s. 777. ISSN 0009-2770. [International Conference on Polysaccharides-Glycoscience 2009 /5./. Praha (CZ), 11.11.2009-13.11.2009] Institutional research plan: CEZ:AV0Z40720504 Keywords : cellulose * reaction progress * chromatography Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  4. Processing and characterization of natural cellulose fibers/thermoset polymer composites.

    Science.gov (United States)

    Thakur, Vijay Kumar; Thakur, Manju Kumari

    2014-08-30

    Recently natural cellulose fibers from different biorenewable resources have attracted the considerable attraction of research community all around the globe owing to their unique intrinsic properties such as biodegradability, easy availability, environmental friendliness, flexibility, easy processing and impressive physico-mechanical properties. Natural cellulose fibers based materials are finding their applications in a number of fields ranging from automotive to biomedical. Natural cellulose fibers have been frequently used as the reinforcement component in polymers to add the specific properties in the final product. A variety of cellulose fibers based polymer composite materials have been developed using various synthetic strategies. Seeing the immense advantages of cellulose fibers, in this article we discuss the processing of biorenewable natural cellulose fibers; chemical functionalization of cellulose fibers; synthesis of polymer resins; different strategies to prepare cellulose based green polymer composites, and diverse applications of natural cellulose fibers/polymer composite materials. The article provides an in depth analysis and comprehensive knowledge to the beginners in the field of natural cellulose fibers/polymer composites. The prime aim of this review article is to demonstrate the recent development and emerging applications of natural cellulose fibers and their polymer materials. PMID:24815407

  5. Effect of Pour Size on Concrete Placing Productivity in Nigeria

    OpenAIRE

    Olaoluwa Olatunde; Ojo Stephen Okunlola; Adesanya David Abiodun

    2012-01-01

    Pour size as one of the site factors affecting concreting was examined to determine its effects on concreting productivity. A total of 167 separate concrete pours were observed on 25 building construction sites in Lagos, Nigeria,comprising 35 pours placed by crane and skip; 26 pours placed by dumper; 58 pours placed by wheelbarrow; 37 pours placed by head pan; and 11 pours placed jointly by pump, wheelbarrow and head pan. Data collected from the daily concrete pours were analyzed to determine...

  6. Tubes légers à haute résistance pour des applications pétrolières marines Light High Strength Tubes for Offshore Petroeleum Applications

    Directory of Open Access Journals (Sweden)

    Corteville J.

    2006-11-01

    Full Text Available Les besoins nouveaux en tubes à haute résistance, créés par le développement actuel des gisements pétroliers marins, nous ont conduits à étudier des tubes composites particuliers, élaborés par enrouiement hélicoïdal de rubans d'acier minces à haute résistance enrobés d'une résine époxy polymérisable. Un mode de recouvrement adapté des rubans d'acier confère au composite une bonne étanchéité et des caractéristiques mécaniques élevées. Les propriétés physiques et chimiques de la matrice de résine permettent également d'obtenir une faible densité et une résistance convenable à la corrosion par les fluides pétroliers, l'eau de mer ou les boues de forage. Cette étude préliminaire comporte une analyse théorique simplifiée de ce type de structure composite, puis une partie expérimentale destinée a sélectionner les caractéristiques optimales de l'acier et de la résine et à vérifier les propriétés mécaniques et physico-chimiques obtenues sur ces tubes. Enfin, des exemples d'application en mer profonde destinés à comparer ces tubes composites aux tubes en acier sont présentés. Les premières conclusions de cette étude semblent confirmer l'intérêt de ce type de matériau pour ces applications. The new requirements for high-strength tubes created by thé current development of offshore oilfields led thé authors ta study thé development ot spécial composite tubes formed by thé spiral winding of high-strength thin steel strips coated with a polymerïzable epoxy resin. A particular method of overlapping thé steel strips makes the composite leakproof and leads to good mechanical properties: The physical and chemical properties of thé resin matrix also make for a low specific gravity and suitable résistance to corrosion coused by petroleum fluids, seawater or drilling mud. This preliminary article presents a simplified theoretical analysis of this type of composite structure, followed by an exp

  7. How recombinant swollenin from Kluyveromyces lactis affects cellulosic substrates and accelerates their hydrolysis

    Directory of Open Access Journals (Sweden)

    Jäger Gernot

    2011-09-01

    Full Text Available Abstract Background In order to generate biofuels, insoluble cellulosic substrates are pretreated and subsequently hydrolyzed with cellulases. One way to pretreat cellulose in a safe and environmentally friendly manner is to apply, under mild conditions, non-hydrolyzing proteins such as swollenin - naturally produced in low yields by the fungus Trichoderma reesei. To yield sufficient swollenin for industrial applications, the first aim of this study is to present a new way of producing recombinant swollenin. The main objective is to show how swollenin quantitatively affects relevant physical properties of cellulosic substrates and how it affects subsequent hydrolysis. Results After expression in the yeast Kluyveromyces lactis, the resulting swollenin was purified. The adsorption parameters of the recombinant swollenin onto cellulose were quantified for the first time and were comparable to those of individual cellulases from T. reesei. Four different insoluble cellulosic substrates were then pretreated with swollenin. At first, it could be qualitatively shown by macroscopic evaluation and microscopy that swollenin caused deagglomeration of bigger cellulose agglomerates as well as dispersion of cellulose microfibrils (amorphogenesis. Afterwards, the effects of swollenin on cellulose particle size, maximum cellulase adsorption and cellulose crystallinity were quantified. The pretreatment with swollenin resulted in a significant decrease in particle size of the cellulosic substrates as well as in their crystallinity, thereby substantially increasing maximum cellulase adsorption onto these substrates. Subsequently, the pretreated cellulosic substrates were hydrolyzed with cellulases. Here, pretreatment of cellulosic substrates with swollenin, even in non-saturating concentrations, significantly accelerated the hydrolysis. By correlating particle size and crystallinity of the cellulosic substrates with initial hydrolysis rates, it could be shown that

  8. Essays concerning the cellulosic biofuel industry

    Science.gov (United States)

    Rosburg, Alicia Sue

    Despite market-based incentives and mandated production, the U.S. cellulosic biofuel industry has been slow to develop. This dissertation explores the economic factors that have limited industry development along with important economic tradeoffs that will be encountered with commercial-scale production. The first essay provides an overview of the policies, potential, and challenges of the biofuel industry, with a focus on cellulosic biofuel. The second essay considers the economics of cellulosic biofuel production. Breakeven models of the local feedstock supply system and biofuel refining process are constructed to develop the Biofuel Breakeven (BioBreak) program, a stochastic, Excel-based program that evaluates the feasibility of local biofuel and biomass markets under various policy and market scenarios. An application of the BioBreak program is presented using expected market conditions for 14 local cellulosic biofuel markets that vary by feedstock and location. The economic costs of biofuel production identified from the BioBreak application are higher than frequently anticipated and raise questions about the potential of cellulosic ethanol as a sustainable and economical substitute for conventional fuels. Program results also are extended using life-cycle analysis to evaluate the cost of reducing GHG emissions by substituting cellulosic ethanol for conventional fuel. The third essay takes a closer look at the economic trade-offs within the biorefinery industry and feedstock production processes. A long-run biomass production through bioenergy conversion cost model is developed that incorporates heterogeneity of biomass suppliers within and between local markets. The model builds on previous literature by treating biomass as a non-commoditized feedstock and relaxes the common assumption of fixed biomass density and price within local markets. An empirical application is provided for switchgrass-based ethanol production within U.S. crop reporting districts

  9. Application in the Ethanol Fermentation of Immobilized Yeast Cells in Matrix of Alginate/Magnetic Nanoparticles, on Chitosan-Magnetite Microparticles and Cellulose-coated Magnetic Nanoparticles

    CERN Document Server

    Ivanova, Viara; Hristov, Jordan

    2011-01-01

    Saccharomyces cerevisiae cells were entrapped in matrix of alginate and magnetic nanoparticles and covalently immobilized on magnetite-containing chitosan and cellulose-coated magnetic nanoparticles. Cellulose-coated magnetic nanoparticles with covalently immobilized thermostable {\\alpha}-amylase and chitosan particles with immobilized glucoamylase were also prepared. The immobilized cells and enzymes were applied in column reactors - 1/for simultaneous corn starch saccharification with the immobilized glucoamylase and production of ethanol with the entrapped or covalently immobilized yeast cells, 2/ for separate ethanol fermentation of the starch hydrolysates with the fixed yeasts. Hydrolysis of corn starch with the immobilized {\\alpha}-amylase and glucoamylase, and separate hydrolysis with the immobilized {\\alpha}-amylase were also examined. In the first reactor the ethanol yield reached approx. 91% of the theoretical; the yield was approx. 86% in the second. The ethanol fermentation was affected by the typ...

  10. Radiation induced graft copolymerization of cellulosic fabric waste and its application in the removal of cyanide and dichromate from aqueous solution

    International Nuclear Information System (INIS)

    Graft polymerization and crosslinking in radiation processing are attractive techniques for modification of the chemical and physical properties of the conventional polymers. The graft polymerization and subsequent chemical treatment can introduce a chelate agent function into a conventional polymer such as cellulosic fabric. Cellulosic graft copolymers were prepared by the reaction of the fiber with acrylonitrile (AN) and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) in DMF initiated by gamma-radiation 60Co. The grafted fabric was chemically treated with hydroxyl amine to obtain amidoxime form. Factors affecting on the grafting such as radiation dose, monomer concentration and solvent concentration as well as monomer composition was investigated. The chemically modified graft fabric was applied for recovery of cyanide and dichromate from aqueous solution. The CN show removal percent 89%, whereas dichromate has 65% removal percent

  11. Application Research Progress of Ionic Liquids in Cellulose Chemistry%离子液体在纤维素化学中的应用研究新进展

    Institute of Scientific and Technical Information of China (English)

    张金明; 吕玉霞; 罗楠; 武进; 余坚; 何嘉松; 张军

    2011-01-01

    As the most abundant natural polymer on the earth, cellulose has many attractive properties such as renewability, biodegradability, biocompatibility, and broad chemical-modifying capacity. Cellulose has been considered as the sustainable raw material of energy and chemical engineering in the future. However, because of the well-developed intra- and intermolecular hydrogen bonding network,cellulose is unmeltable and insoluble in water or conventional organic solvents,which limits its wide utilization. More recently, it is found that certain ionic liquids (ILs) have excellent dissolving capability for cellulose,which provids a new and versatile platform for cellulose processing and derivatization. A series of biopolymer-based materials, biomass energy, platform chemicals, and so on,have been produced with the aid of ILs. Based on about 210 relevant papers published during the past 10 years, this review article highlights recent progress in the field of dissolution, regeneration, derivatization, extraction and conversion of cellulose with ILs. In additon, a perspective on ILs application in cellulose chemistry in the future is briefly discussed. It is hoped that this review work will stimulate research and collaborations that will lead to significant progress in this area.%纤维素是自然界中储量最大的天然高分子,具有可再生、可完全生物降解、生物相容性好等诸多优点,被认为是未来能源、化工的主要原料。由于聚集态结构的特点,天然纤维素不熔融、难溶解,使其应用受到极大限制。近年来,人们发现一定结构的离子液体可以高效地溶解纤维素,这为纤维素的加工与功能化提供了一个崭新和多用途的平台。以离子液体为介质,通过溶解再生和均相衍生化反应可以制得一系列纤维素基高分子材料;通过催化分解等方法,可以得到不同类型的生物质能源以及平台化合物等,从而极大地拓展了纤

  12. When It Rains, It Pours

    Science.gov (United States)

    Mills, Linda

    2012-01-01

    "It's raining, it's pouring, the old man is snoring!" "The itsy, bitsy spider crawled up the waterspout, down came the rain and washed the spider out. Out came the sun and dried up all the rain, and the itsy, bitsy spider went up the spout again." What do children's nursery rhymes have to do with the school library? The author begins by telling a…

  13. Synthesis and characterization of cellulose derivatives obtained from bacterial cellulose

    International Nuclear Information System (INIS)

    The chemical modification of cellulose leads to production of derivatives with different properties from those observed for the original cellulose, for example, increased solubility in more traditional solvents. In this work we synthesized four derivatives of cellulose: microcrystalline cellulose, cellulose acetate, methylcellulose and carboxymethylcellulose using bacterial cellulose as a source. These were characterized in terms of chemical and structural changes by examining the degree of substitution (DS), infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy - NMR 13C. The molecular weight and degree of polymerization were evaluated by viscometry. The characterization of the morphology of materials and thermal properties were performed with the techniques of X-ray diffraction, electron microscopy images, differential scanning calorimetry (DSC) and thermogravimetric analysis. (author)

  14. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles

    Science.gov (United States)

    It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of th...

  15. Blends of dissolved cellulose with acrylic acid copolymers or microfibrillated cellulose

    OpenAIRE

    Saarikoski, Eve

    2015-01-01

    The aim of the thesis was to develop dissolved cellulose (dissolved in NaOH/ZnO) based blends with acrylic acid copolymers (poly(ethylene-co-acrylic acid) (PE-co-AA) or poly(acrylamide-co-acrylic acid) (PAA-co-AA)) or microfibrillated cellulose (MFC) in the way they could be used in injection molding or for film/coating applications. This thesis summarizes the research reported in five publications supported by some unpublished results. Rheological studies done in the contexts of this work...

  16. [Insights into engineering of cellulosic ethanol].

    Science.gov (United States)

    Yue, Guojun; Wu, Guoqing; Lin, Xin

    2014-06-01

    For energy security, air pollution concerns, coupled with the desire to sustain the agricultural sector and revitalize the rural economy, many countries have applied ethanol as oxygenate or fuel to supplement or replace gasoline in transportation sector. Because of abundant feedstock resources and effective reduction of green-house-gas emissions, the cellulosic ethanol has attracted great attention. With a couple of pioneers beginning to produce this biofuel from biomass in commercial quantities around the world, it is necessary to solve engineering problems and complete the economic assessment in 2015-2016, gradually enter the commercialization stage. To avoid "competing for food with humans and competing for land with food", the 1st generation fuel ethanol will gradually transit to the 2nd generation cellulosic ethanol. Based on the overview of cellulosic ethanol industrialization from domestic and abroad in recent years, the main engineering application problems encountered in pretreatment, enzymes and enzymatic hydrolysis, pentose/hexose co-fermentation strains and processes, equipment were discussed from chemical engineering and biotechnology perspective. The development direction of cellulosic ethanol technology in China was addressed. PMID:25212000

  17. Production of bacterial cellulose and enzyme from waste fiber sludge

    OpenAIRE

    Cavka, Adnan; Guo, Xiang; Tang, Shui-Jia; Winestrand, Sandra; Jönsson, Leif J.; Hong, Feng

    2013-01-01

    Background: Bacterial cellulose (BC) is a highly crystalline and mechanically stable nanopolymer, which has excellent potential as a material in many novel applications, especially if it can be produced in large amounts from an inexpensive feedstock. Waste fiber sludge, a residue with little or no value, originates from pulp mills and lignocellulosic biorefineries. A high cellulose and low lignin content contributes to making the fiber sludge suitable for bioconversion, even without a thermoc...

  18. Cellulose nanorods in liquid crystalline elastomers for improved actuators

    OpenAIRE

    Pontes, Rita Valério

    2014-01-01

    Nanotechnology plays a central role in ‘tailoring’ materials’ properties and thus improving its performances for a wide range of applications. Coupling nature nano-objects with nanotechnology results in materials with enhanced functionalities. The main objective of this master thesis was the synthesis of nanocrystalline cellulose (NCCs) and its further incorporation in a cellulosic matrix, in order to produce a stimuli-responsive material to moisture. The induced behaviour (bending/unbendi...

  19. Chemical Modification of Microfibrillated Cellulose: Effects on Film Barrier Properties

    OpenAIRE

    Rodionova, Galina

    2011-01-01

    A global demand for environmental sustainability is a strong driving force towards the development of enhanced barrier concepts and the use of new materials, especially for packaging applications. Abundant and renewable, cellulosic fibers have been widely used as one of the main constituents in the fiber-based packaging. However, the porous and hydrophilic structure of cellulose network requires the use of barrier polymer coatings to create an additional resistance against water, water vapors...

  20. Enhanced cellulose degradation using cellulase-nanosphere complexes.

    Directory of Open Access Journals (Sweden)

    Craig Blanchette

    Full Text Available Enzyme catalyzed conversion of plant biomass to sugars is an inherently inefficient process, and one of the major factors limiting economical biofuel production. This is due to the physical barrier presented by polymers in plant cell walls, including semi-crystalline cellulose, to soluble enzyme accessibility. In contrast to the enzymes currently used in industry, bacterial cellulosomes organize cellulases and other proteins in a scaffold structure, and are highly efficient in degrading cellulose. To mimic this clustered assembly of enzymes, we conjugated cellulase obtained from Trichoderma viride to polystyrene nanospheres (cellulase:NS and tested the hydrolytic activity of this complex on cellulose substrates from purified and natural sources. Cellulase:NS and free cellulase were equally active on soluble carboxymethyl cellulose (CMC; however, the complexed enzyme displayed a higher affinity in its action on microcrystalline cellulose. Similarly, we found that the cellulase:NS complex was more efficient in degrading natural cellulose structures in the thickened walls of cultured wood cells. These results suggest that nanoparticle-bound enzymes can improve catalytic efficiency on physically intractable substrates. We discuss the potential for further enhancement of cellulose degradation by physically clustering combinations of different glycosyl hydrolase enzymes, and applications for using cellulase:NS complexes in biofuel production.

  1. Novel oil resistant cellulosic materials

    OpenAIRE

    Aulin, Christian

    2009-01-01

    The aim of this study has been to prepare and characterise oil resistant cellulosic materials, ranging from model surfaces to papers and aerogels. The cellulosic materials were made oil resistant by chemical and topographic modifications, based on surface energy, surface roughness and barrier approaches. Detailed wetting studies of the prepared cellulosic materials were made using contact angle measurements and standardised penetration tests with different alkanes and oil mixtures. A signific...

  2. Cellulose biogenesis in Dictyostelium discoideum

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, R.L.

    1993-12-31

    Organisms that synthesize cellulose can be found amongst the bacteria, protistans, fungi, and animals, but it is in plants that the importance of cellulose in function (as the major structural constituent of plant cell walls) and economic use (as wood and fiber) can be best appreciated. The structure of cellulose and its biosynthesis have been the subjects of intense investigation. One of the most important insights gained from these studies is that the synthesis of cellulose by living organisms involves much more than simply the polymerization of glucose into a (1{r_arrow}4)-{beta}-linked polymer. The number of glucoses in a polymer (the degree of polymerization), the crystalline form assumed by the glucan chains when they crystallize to form a microfibril, and the dimensions and orientation of the microfibrils are all subject to cellular control. Instead of cellulose biosynthesis, a more appropriate term might be cellulose biogenesis, to emphasize the involvement of cellular structures and mechanisms in controlling polymerization and directing crystallization and deposition. Dictyostelium discoideum is uniquely suitable for the study of cellulose biogenesis because of its amenability to experimental study and manipulation and the extent of our knowledge of its basic cellular mechanisms (as will be evident from the rest of this volume). In this chapter, I will summarize what is known about cellulose biogenesis in D. discoideum, emphasizing its potential to illuminate our understanding both of D. discoideum development and plant cellulose biogenesis.

  3. End-functionalization of cellulose nanocrystals

    OpenAIRE

    Lundahl, Meri

    2014-01-01

    Regioselective modification of nanocelluloses can have intriguing applications in self-assembled material synthesis. In this thesis, cellulose nanocrystals (CNC) were selectively functionalized at their reducing ends with thiol and maleimide groups. For thiol end-functionalization, a protocol was developed based on NHS/EDC-catalyzed coupling of NaClO2-oxidized CNCs with NH2 (CH2)6 SH in water. Maleimide end-functionalization was achieved by reacting end-thiolated CNCs (CNC SH) with a homobifu...

  4. Nanofibrillated Cellulose Surface Modification: A Review

    OpenAIRE

    Julien Bras,; Mohamed Naceur Belgacem; Karim Missoum

    2013-01-01

    Interest in nanofibrillated cellulose (NFC) has increased notably over recent decades. This bio-based nanomaterial has been used essentially in bionanocomposites or in paper thanks to its high mechanical reinforcement ability or barrier property respectively. Its nano-scale dimensions and its capacity to form a strong entangled nanoporous network have encouraged the emergence of new high-value applications. It is worth noting that chemical surface modification of this material can be a key fa...

  5. Cellulose nanocrystals : surface modification and advanced materials

    OpenAIRE

    Lin, Ning

    2014-01-01

    The present work focuses on the properties of cellulose nanocrystals, their surface modification and development of advanced materials. Diverse approaches are employed on these nanoscaled substrates aiming to modify their surface properties and extend their use in highly sophisticated applications, such as postsulfation and desulfation, polymer grafting and adsorption, selective oxidation, molecular grafting, and ‘host-guest' inclusion. On the basis of surface modifications, properties analys...

  6. Development and Testing of Xanthan Products for Eor-Applications in the North Sea Développement et essais des produits à base de xanthane pour les applications de RAH en mer du Nord

    Directory of Open Access Journals (Sweden)

    Foss P.

    2006-11-01

    Full Text Available A program for development and evaluation of xanthan for use in enhanced oil recovery projects in the North Sea has been performed. Xanthan was produced using different fermentation conditions. Rheological measurements and filterability tests have been done. Xanthan products, which readily dissolve in sea water and give high viscosity and low aggregation have been produced. The fermentation process used for this type of product was scaled up from 10 litres to 20,000 litres production volume without significant changes in polymer solution properties. Un programme de développement et d'évaluation du xanthane pour utilisation dans les projets de récupération assistée des hydrocarbures en mer du Nord a été réalisé. Le xanthane est obtenu par différents procédés de fermentation. On a effectué des mesures rhéologiques et des essais de filtrabilité. Les produits à base de xanthane se dissolvent facilement dans l'eau de mer, ils donnent une forte viscosité et une faible agrégation. Avec le procédé de fermentation utilisé pour ce type de produit, on a pu faire passer la production de 10 litres à 20000 litres sans modification notable des propriétés de la solution de polymère.

  7. Nanocellulose patents trends: a comprehensive review on patents on cellulose nanocrystals, microfibrillated and bacterial cellulose.

    Science.gov (United States)

    Charreau, Hernan; Foresti, Maria L; Vazquez, Analia

    2013-01-01

    Cellulose nanoparticles (i.e. cellulose elements having at least one dimension in the 1-100 nm range) have received increasing attention during the last decade. This is not only evident in academic articles, but it is also manifested by the increasing number of nanocellulose patents that are published every year. In the current review, nanocellulose patents are reviewed using specific software which provides valuable information on the annual number of patents that have been published throughout the years, main patent owners, most prolific inventors, and patents on the field that have received more citations. Patent statistics on rod-like cellulose nanoparticles extracted from plants by acid hydrolysis (nanocrystals), mechanical treatment leading to microfibrillated cellulose (MFC), and microbially produced nanofibrils (bacterial cellulose, BC) are analyzed in detail. The aim of the current review is to provide researchers with patent information which may help them in visualizing the evolution of nanocellulose technology, both as a whole and also divided among the different nanosized particles that are currently the subject of outstanding scientific attention. Then, patents are not only analyzed by their content, but also by global statistics which will reveal the moment at which different cellulose nanoparticles technologies achieved a breakthrough, the relative interest received by different nanocellulose particles throughout the years, the companies that have been most interested in this technology, the most prolific inventors, and the patents that have had more influence in further developments. It is expected that the results showing the explosion that nanocellulose technology is experiencing in current days will still bring more research on the topic and contribute to the expansion of nanocellulosics applications. PMID:22747719

  8. Synthesis and properties of fluorescent cotton cellulose labeled with norfloxacin

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To expand the application of cellulose in the field of fluorescence techniques, the cotton cellulose was labeled with norfloxacin (Cell-NF) via a three-step reaction, involving alkali treatment, epoxy activation, and opening of the epoxy rings with norfloxacin molecules. And the coordination complexes of Cell-NF with rare earth ions terbium (Cell-NF-Tb) and europium (Cell-NF-Eu) were obtained. The products were detected by IR, TG, XPS, UV and fluorescence spectra. Results showed that the norfloxacin content of the labeled cellulose was about 6.73 w‰ and the start temperature of decomposition of the Cell-NF was raised by 40°C compared with the stock cotton cellulose. When excited at 340 nm, the Cell-NF, Cell-NF-Tb, and Cell-NF-Eu in the solid state could emit violet (430 nm), green (549 nm) and red (620 nm) light, respectively.

  9. Preparation of succinylated cellulose membranes for functionalization purposes.

    Science.gov (United States)

    Ribeiro-Viana, Renato M; Faria-Tischer, Paula C S; Tischer, Cesar A

    2016-09-01

    The anhydroglucose chains of cellulose possess hydroxyls that facilitate different chemical modification strategies to expand on, or provide new applications for membranes produced by the bacteria Gluconacetobacter xylinus. Conjugation with biomolecules such as proteins, especially by the amine groups, is of great value and interest for the production of biomaterial derivatives from bacterial cellulose. To assist in these modifications, cellulose was succinylated in order to prevent steric hindrance and to create an attachment point for conjugation. Bacterial cellulose membranes were first treated in dichloromethane and reacted with succinic anhydride through a series of conditions. The membrane structure remained intact after these first processes and the product was confirmed by Infra-Red spectroscopy and solid state nuclear magnetic resonance and characterized by X-ray diffraction, thermogravimetry and atomic force microscopy. Hydrolyzed collagen was used as a model protein of interest to be conjugated to these membranes, which furnished a biomaterial functionalized over its surface. PMID:27185111

  10. Hairy cellulose nanocrystalloids: a novel class of nanocellulose.

    Science.gov (United States)

    van de Ven, Theo G M; Sheikhi, Amir

    2016-08-18

    Nanomaterials have secured such a promising role in today's life that imagining the modern world without them is almost impossible. A large fraction of nanomaterials is synthesized from environmentally-dangerous elements such as heavy metals, which have posed serious side-effects to ecosystems. Despite numerous advantages of synthetic nanomaterials, issues such as renewability, sustainability, biocompatibility, and cost efficiency have drawn significant attention towards natural products such as cellulose-based nanomaterials. Within the past decade, nanocelluloses, most remarkably nanocrystalline cellulose (NCC) and nanofibrillated cellulose (NFC), have successfully been used for a wide spectrum of applications spanning from nanocomposites, packaging, and mechanical and rheological property modifications, to chemical catalysis and organic templating. Yet, there has been little effort to introduce fundamentally new polysaccharide-based nanomaterials. We have been able to develop the first kind of cellulose-based nanoparticles bearing both crystalline and amorphous regions. These nanoparticles comprise a crystalline body, similar to conventional NCC, but with polymer chains protruding from both ends; therefore, these particles are called hairy cellulose nanocrystalloids (HCNC). In this article, we touch on the philosophy of HCNC synthesis, the striking superiority over existing nanocelluloses, and applications of this novel class of nanocelluloses. We hope that the emergence of hairy cellulose nanocrystalloids extends the frontiers of sustainable, green nanotechnology. PMID:27453347

  11. Water-repellent cellulose fiber networks with multifunctional properties.

    Science.gov (United States)

    Bayer, Ilker S; Fragouli, Despina; Attanasio, Agnese; Sorce, Barbara; Bertoni, Giovanni; Brescia, Rosaria; Di Corato, Riccardo; Pellegrino, Teresa; Kalyva, Maria; Sabella, Stefania; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2011-10-01

    We demonstrate a simple but highly efficient technique to introduce multifunctional properties to cellulose fiber networks by wetting them with ethyl-cyanoacrylate monomer solutions containing various suspended organic submicrometer particles or inorganic nanoparticles. Solutions can be applied on cellulosic surfaces by simple solution casting techniques or by dip coating, both being suitable for large area applications. Immediately after solvent evaporation, ethyl-cyanoacrylate starts cross-linking around cellulose fibers under ambient conditions because of naturally occurring surface hydroxyl groups and adsorbed moisture, encapsulating them with a hydrophobic polymer shell. Furthermore, by dispersing various functional particles in the monomer solutions, hydrophobic ethyl-cyanoacrylate nanocomposites with desired functionalities can be formed around the cellulose fibers. To exhibit the versatility of the method, cellulose sheets were functionalized with different ethyl-cyanoacrylate nanocomposite shells comprising submicrometer wax or polytetrafluoroethylene particles for superhydophobicity, MnFe(2)O(4) nanoparticles for magnetic activity, CdSe/ZnS quantum dots for light emission, and silver nanoparticles for antimicrobial activity. Morphological and functional properties of each system have been studied by scanning and transmission electron microscopy, detailed contact angle measurements, light emission spectra and E. coli bacterial growth measurements. A plethora of potential applications can be envisioned for this technique, such as food and industrial packaging, document protection, catalytic cellulosic membranes, textronic (electrofunctional textiles), electromagnetic devices, authentication of valuable documents, and antimicrobial wound healing products to name a few. PMID:21902239

  12. ACCESSIBILITY AND CRYSTALLINITY OF CELLULOSE

    Directory of Open Access Journals (Sweden)

    Michael Ioelovich

    2009-08-01

    Full Text Available The accessibility of cellulose samples having various degrees of crystallinity was studied with respect to molecules of water, lower primary alcohols, and lower organic acids. It was found that small water molecules have full access to non-crystalline domains of cellulose (accessibility coefficient α = 1. Molecules of the lowest polar organic liquids (methanol, ethanol, and formic acid have partial access into the non-crystalline domains (α<1, and with increasing diameter of the organic molecules their accessibility to cellulose structure decreases. Accessibility of cellulose samples to molecules of various substances is a linear function of the coefficient α and the content of non-crystalline domains. The relationship between crystallinity (X and accessibility (A of cellulose to molecules of some liquids has been established as A = α (1-X. The water molecules were found to have greater access to cellulose samples than the molecules of the investigated organic liquids. The obtained results permit use of accessibility data to estimate the crystallinity of cellulose, to examine the structural state of non-crystalline domains, and to predict the reactivity of cellulose samples toward some reagents.

  13. Cellulose Synthesis in Agrobacterium tumefaciens

    Energy Technology Data Exchange (ETDEWEB)

    Alan R. White; Ann G. Matthysse

    2004-07-31

    We have cloned the celC gene and its homologue from E. coli, yhjM, in an expression vector and expressed the both genes in E. coli; we have determined that the YhjM protein is able to complement in vitro cellulose synthesis by extracts of A. tumefaciens celC mutants, we have purified the YhjM protein product and are currently examining its enzymatic activity; we have examined whole cell extracts of CelC and various other cellulose mutants and wild type bacteria for the presence of cellulose oligomers and cellulose; we have examined the ability of extracts of wild type and cellulose mutants including CelC to incorporate UDP-14C-glucose into cellulose and into water-soluble, ethanol-insoluble oligosaccharides; we have made mutants which synthesize greater amounts of cellulose than the wild type; and we have examined the role of cellulose in the formation of biofilms by A. tumefaciens. In addition we have examined the ability of a putative cellulose synthase gene from the tunicate Ciona savignyi to complement an A. tumefaciens celA mutant. The greatest difference between our knowledge of bacterial cellulose synthesis when we started this project and current knowledge is that in 1999 when we wrote the original grant very few bacteria were known to synthesize cellulose and genes involved in this synthesis were sequenced only from Acetobacter species, A. tumefaciens and Rhizobium leguminosarum. Currently many bacteria are known to synthesize cellulose and genes that may be involved have been sequenced from more than 10 species of bacteria. This additional information has raised the possibility of attempting to use genes from one bacterium to complement mutants in another bacterium. This will enable us to examine the question of which genes are responsible for the three dimensional structure of cellulose (since this differs among bacterial species) and also to examine the interactions between the various proteins required for cellulose synthesis. We have carried out one

  14. Surface modification of cellulose materials : from wood pulps to artificial blood vessels

    OpenAIRE

    Ahrenstedt, Lage

    2007-01-01

    This thesis describes the improvement of two radically different cellulose materials, paper and artificial blood vessels, constructed from two diverse cellulose sources, wood pulp and Acetobacter xylinum. The improvement of both materials was possible due to the natural affinity of the hemicellulose xyloglucan for cellulose. Chemical and mechanical pulps were treated with xyloglucan in the wet-end prior to hand sheet formation or by spray application of dry hand sheets, loading a comparable a...

  15. Preparation and characterization of directly compactible layer-by-layer nanocoated cellulose

    OpenAIRE

    Liebenberg, Wilna; Strydom, Schalk J.; Otto, Daniel P.; Yuri M. Lvov; de Villiers, Melgardt M.

    2011-01-01

    Microcrystalline cellulose is a commonly used direct compression tablet diluent and binder. It is derived from purified α-cellulose in an environmentally unfriendly process that involves mineral acid catalysed hydrolysis. In this study Kraft softwood fibers was nanocoated using a layer-by-layer self-assembling process. Powder flow and compactibility results showed that the application of nano-thin polymer layers on the fibers turned non-flowing, non-compacting cellulose into powders that can ...

  16. Cellulose-based composites as functional conductive materials for printed electronics

    OpenAIRE

    Barras, Raquel Alexandra Antunes

    2015-01-01

    In this work, cellulose-based electro and ionic conductive composites were developed for application in cellulose based printed electronics. Electroconductive inks were successfully formulated for screen-printing using carbon fibers (CFs) and multi-walled carbon nanotubes (MWCNTs) as conductive functional material and cellulose derivatives working as binder. The formulated inks were used to fabricate conductive flexible and disposable electrodes on paper-based substrates. Interesting results ...

  17. Cellulose/Gold Nanocrystal Hybrids via an Ionic Liquid/Aqueous Precipitation Route

    Directory of Open Access Journals (Sweden)

    Andreas Taubert

    2009-11-01

    Full Text Available Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials.

  18. Novel In Vivo-Degradable Cellulose-Chitin Copolymer from Metabolically Engineered Gluconacetobacter xylinus▿ †

    OpenAIRE

    Yadav, Vikas; Paniliatis, Bruce J.; Shi, Hai; Lee, Kyongbum; Cebe, Peggy; Kaplan, David L.

    2010-01-01

    Despite excellent biocompatibility and mechanical properties, the poor in vitro and in vivo degradability of cellulose has limited its biomedical and biomass conversion applications. To address this issue, we report a metabolic engineering-based approach to the rational redesign of cellular metabolites to introduce N-acetylglucosamine (GlcNAc) residues into cellulosic biopolymers during de novo synthesis from Gluconacetobacter xylinus. The cellulose produced from these engineered cells (modif...

  19. Ultrasonic dyeing of cellulose nanofibers.

    Science.gov (United States)

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing. PMID:26964959

  20. Amélioration de la précision des robots industriels pour des applications d'usinage a grande vitesse

    OpenAIRE

    OLABI, Adel

    2011-01-01

    Industrial robots are usually used to realize industrial tasks like material handling, welding, cutting and spray painting. The mobility, flexibility and important work space of these robots allow using them in new fields of industry such as prototyping, cleaning and pre-machining of casts parts as well as end-machining of middle tolerance parts. These new applications require a high level pose accuracy and to achieve a good path tracking. Unfortunately industrial robots were designed to have...

  1. Estimation de l'état pour la surveillance des systèmes de grandes dimensions. Application aux réseaux électriques

    OpenAIRE

    Thabet, Assem

    2012-01-01

    This work deals with the state estimation and diagnosis of nonlinear systems with application to power systems. Dynamic modeling is performed using an index 1 property and decoupling techniques. New methods of state estimation, based on Extended Kalman Filter including a sliding window of measurements, are proposed to improve the robustness and accuracy. A new convergence study based on Lyapunov function and conditioning of the observability matrix is proposed to ensure the convergence of the...

  2. Contribution à la Modélisation et à la Gestion Thermique des Batteries Lithium-Ion pour des Applications de Véhicules Electriques

    OpenAIRE

    samba, ahmadou

    2015-01-01

    disponible: Bibliothèque : Université de Caen Normandie. Bibliothèque universitaire Sciences - STAPS Advanced research on rechargeable Lithium-ion batteries has allowed for large format and high-energy batteries to be largely used in Battery Electric Vehicles (BEVs). For transportation applications, beside limitations of driving range, long charging time is still considered as an important barrier for a wide use of BEVs. The increase of the charging current amplitude may however subject th...

  3. Analyse statique/dynamique pour la validation et l'amélioration des applications parallèles multi-modèles

    OpenAIRE

    Saillard, Emmanuelle

    2015-01-01

    Supercomputing plays an important role in several innovative fields, speeding up prototyping or validating scientific theories. However, supercomputers are evolving rapidly with now millions of processing units, posing the questions of their programmability. Despite the emergence of more widespread and functional parallel programming models, developing correct and effective parallel applications still remains a complex task. Although debugging solutions have emerged to address this issue, the...

  4. Méthodes régularisées pour la prédiction dans les graphes dynamiques et applications au e-marketing

    OpenAIRE

    Richard, Émile

    2012-01-01

    Predicting connections among objects, based either on a noisy observation or on a sequence of observations, is a problem of interest for numerous applications such as recommender systems for e-commerce and social networks, and also in system biology, for inferring interaction patterns among proteins. This work presents formulations of the graph prediction problem, in both dynamic and static scenarios, as regularization problems. In the static scenario we encode the mixture of two different ki...

  5. Reinforced plastics and aerogels by nanocrystalline cellulose

    International Nuclear Information System (INIS)

    Nanocrystalline cellulose (NCC), a rigid rod-like nanoscale material, can be produced from cellulosic biomass in powder, liquid, or gel forms by acid and chemical hydrolysis. Owing to its unique and exceptional physicochemical properties, the incorporation of a small amount of NCC into plastic enhances the mechanical strength of the latter by several orders of magnitudes. Carbohydrate-based NCC poses no serious environmental concerns, providing further impetus for the development and applications of this green and renewable biomaterial to fabricate lightweight and biodegradable composites and aerogels. Surface functionalization of NCC remains the main focus of NCC research to tailor its properties for dispersion in hydrophilic or hydrophobic media. It is of uttermost importance to develop tools and protocols for imaging of NCC in a complex matrix and quantify its reinforcement effect.

  6. Process Dependence of Cellulose Nanofiber Fabrication

    Science.gov (United States)

    Henderson, Doug; Zhang, Xin; Mao, Yimin; Jang, Soo-Hwan; Hu, Liangbing; Briber, Robert; Wang, Howard

    Cellulose nanofibers (CNF) are the most abundant natural nanomaterial on earth with potential applications in renewable energy, polymer nanocomposites and flexible electronics. CNF can be produced through TEMPO oxidation which separates the hierarchical structure of cellulose fibers into smaller micro- and nanofibers by altering their surface chemistry, inducing a repulsive electrostatic charge on the fibers. This work will examine the structural evolution of CNF during production. Samples were prepared by removing and quenching aliquots during the TEMPO reaction. The fibers were washed, filtered and re-dispersed into D2O for small angle neutron scattering (SANS) measurements. The SANS data was analyzed to track the changes in the CNF structure as a function of reaction time.

  7. Contribution à la modélisation des structures SIW et SINRD pour application micro-ondes et télécommunication

    OpenAIRE

    Ismail Alhzzoury, Ahmad

    2013-01-01

    Les développements technologiques en télécommunication et microondes tendent depuis plusieurs années vers la miniaturisation des circuits, une réduction des coûts, des masses et des pertes dans ces dispositifs. Les circuits SIW (Substrate Integrated Waveguide) s’inscrivent tout à fait dans cette mouvance et font à l’heure actuelle l’objet de nombreux sujets de recherche avec des applications directes dans l’industrie. Les circuits SINRD (Substrate Integrated Non Radiative Dielectric) utilisen...

  8. La provision de services sémantiques pour 6LoWPAN : faciliter le développement des applications IoT sur le Web

    OpenAIRE

    Han, Ngoc Son

    2015-01-01

    This dissertation proposes a complete solution to provision 6LoWPAN services with semantic annotation that enables the development of IoT applications on Web. We aim to bring smart object services to the Web and make them accessible by plenty of existing Web APIs in consideration of 6LoWPAN constraints such as limited resources (ROM, RAM, and CPU), low-power, and low-bitrate communication links. There are four contributions: (i) The first contribution is about the overall architecture of the ...

  9. Une approche pour la composition autonome de services de communication orientés QoS. Application aux protocoles de transport configurables

    OpenAIRE

    Van Wambeke, Nicolas

    2009-01-01

    Les dernières évolutions de l’Internet se sont traduites par l’émergence de nouvelles applications distribuées et par la multiplication des technologies réseaux (sans fils, mobiles. . . ) ainsi que des services offerts par les opérateurs sur de nouveaux types de terminaux (portable, PDA. . . ). L’enjeu socio économique majeur de ces avancées est le futur Internet ambiant, à la fois ubiquitaire et intelligent, au travers duquel l’utilisateur pourra, quelle que soit sa localisation ...

  10. Mécanismes d'interaction du laser femtoseconde avec le tissu pour des applications en greffe de cornée

    OpenAIRE

    Nuzzo, Valeria

    2008-01-01

    Mon projet de doctorat s'est déroulé au Laboratoire d'Optique Appliquée de l'Ecole Polytechnique, ENSTA, CNRS à Palaiseau, en collaboration avec le Laboratoire Biotechnologie et Oeil, Université Paris V, Hôpital Hôtel Dieu à Paris. Il porte sur l'étude des phénomènes d'interaction du rayonnement à impulsions ultracourtes avec le tissu et notamment sur les applications des lasers femtoseconde (dont les impulsions durent 10-15 s) en chirurgie de la cornée. Environ 100.000 greffes de cornée sont...

  11. Les obturateurs à cristaux liquide pour la vision stéréoscopique et l'application 3D Dual View

    OpenAIRE

    Nunes Henrique Silva, Vinicius

    2013-01-01

    In this thesis the main objectives were to improve the liquid crystal shutters and to develop a stereoscopic vision application called 3D Dual View. The vision quality of a 3D system based on active glasses is direct related to the performance of the liquid crystal shutters. There are a lot of parameters that plays an important role in the quality of 3D glasses. Thus, efforts were concentrated in the organization of the liquid crystal molecules between the substrates and in the liquid crystal...

  12. Développement par voie Sol-Gel de méthodes d'assemblage de cristaux à optique non linéaire pour applications laser

    OpenAIRE

    Sraïki, Guillaume

    2015-01-01

    In this CIFRE thesis we elaborate a bonding solution, with Cristal Laser and Oxxius companies, for non-linear optical crystals for laser applications. We had to optimize solution’s composition and the bonding process, this resulted in the creation of a bonding robot by our industrial partners. Numerous homo-assemblies bonding tests has been realized with the following crystal pairs of SiO2, Quartz, YAG, KTP, LBO, BBO and RTP. Those homo-assemblies have been thermally treated to stabilize our ...

  13. Technologies microsystèmes avancées pour le fonctionnement de dispositifs en milieu liquide et les applications nanométriques

    OpenAIRE

    Rollier, Anne-Sophie

    2006-01-01

    To handle cells requires the use of adapted tools. These tools have to establish the link between the microscopic and macroscopic world. The tools naturally adapted to this task are MEMS, they are micromechanical systems having a mobile part making it possible to put them in motion or to deform them. They are ideal tools to seize objects, to probe their surface and to analyze them. MEMS are already used in Atomic Force Microscopy (AFM) for vacuum or air application. This thesis will make it p...

  14. [Microcrystalline cellulose and their flow -- morphological properties modifications as an effective excpients in tablet formulation technology containing lattice established API and also dry plant extract].

    Science.gov (United States)

    Zgoda, Marian Mikołaj; Nachajski, Michał Jakub; Kołodziejczyk, Michał Krzysztof

    2009-01-01

    The production technology of powder cellulose (Arbocel) and microcrystaline cellulose (Vivapur) and their application in the composition of direct compression tablet mass was provided. The function of silicified microcrystaline cellulose type Prosolv in the direct compression process of dry plant extract was discussed. An analysis of the chemical structure of cellulose fiber (Vitacel) enabled determining its properties and applications in the manufacture of diet supplement, pharmaceutical and food products. PMID:19580170

  15. Progress of Preparation and Application of Bacterial Cellulose%细菌纤维素的制备和应用研究进展

    Institute of Scientific and Technical Information of China (English)

    陈竞; 冯蕾; 杨新平

    2014-01-01

    细菌纤维素(Bacterial cellulose,简称BC)又称微生物纤维素,具有独特超细网状纤维结构、不含木质素和其他细胞壁成份,吸水性强、高生物兼容性、可降解性等优良特点,日益成为人们关注的焦点.综述了近年来国内外在细菌纤维素的菌种筛选、碳源优化、发酵工艺方面的研究成果,以及细菌纤维素在肾透析膜、血管支架、皮肤代用品、化妆品膜、减肥代餐食品等方面的应用.

  16. SYNDEX un environnement de programmation pour multi-processeur de traitement du signal. Mecanismes de communication

    OpenAIRE

    Ghezal, Nadia; Matiatos, Spiros; Piovesan, Pascal; Sorel, Yves; Sorine, Michel

    1990-01-01

    Syndex (Acronyme pour EXecutif Distribue SYNchrone) est un environnement graphique interactif de developpement d'applications de traitement du signal pour machines multi-processeur. Nous presentons en introduction, les fonctions assurees par Syndex adaptees a la mise en oeuvre sur machines multiprocesseurs de programmes synchrones ecrits dans le langage Signal, quelques methodes d'optimisation associees, la generation et le reglage du support d'execution. Enfin, nous decrivons rapidement le p...

  17. IMPACTS OF BIOFILM FORMATION ON CELLULOSE FERMENTATION

    Energy Technology Data Exchange (ETDEWEB)

    Leschine, Susan

    2009-10-31

    This project addressed four major areas of investigation: i) characterization of formation of Cellulomonas uda biofilms on cellulose; ii) characterization of Clostridium phytofermentans biofilm development; colonization of cellulose and its regulation; iii) characterization of Thermobifida fusca biofilm development; colonization of cellulose and its regulation; and iii) description of the architecture of mature C. uda, C. phytofermentans, and T. fusca biofilms. This research is aimed at advancing understanding of biofilm formation and other complex processes involved in the degradation of the abundant cellulosic biomass, and the biology of the microbes involved. Information obtained from these studies is invaluable in the development of practical applications, such as the single-step bioconversion of cellulose-containing residues to fuels and other bioproducts. Our results have clearly shown that cellulose-decomposing microbes rapidly colonize cellulose and form complex structures typical of biofilms. Furthermore, our observations suggest that, as cells multiply on nutritive surfaces during biofilms formation, dramatic cell morphological changes occur. We speculated that morphological changes, which involve a transition from rod-shaped cells to more rounded forms, might be more apparent in a filamentous microbe. In order to test this hypothesis, we included in our research a study of biofilm formation by T. fusca, a thermophilic cellulolytic actinomycete commonly found in compost. The cellulase system of T. fusca has been extensively detailed through the work of David Wilson and colleagues at Cornell, and also, genome sequence of a T. fusca strain has been determine by the DOE Joint Genome Institute. Thus, T. fusca is an excellent subject for studies of biofilm development and its potential impacts on cellulose degradation. We also completed a study of the chitinase system of C. uda. This work provided essential background information for understanding how C. uda

  18. Dispositifs pour la cryptographie quantique

    OpenAIRE

    Tualle-Brouri, Rosa

    2006-01-01

    Ce mémoire couvre l'ensemble de mes activités de recherche au laboratoire Charles Fabry, dans le groupe d'optique quantique dirigé par Philippe Grangier. Ces activités entrent dans le cadre de l'information quantique, discipline au carrefour de la théorie de l'information et de la mécanique quantique. Nous nous sommes ainsi attachés à synthétiser et à étudier différents états quantiques de la lumière, avec pour objectif la mise au point de protocoles de cryptographie quantique.

  19. Ontologie Modulaire pour la Collaboration

    OpenAIRE

    Atrash, Ala; Abel, Marie-Hélène; Moulin, Claude

    2014-01-01

    Dans cet article, dans le cadre des ontologies modulaires, nous nous intéressons à la conception et la réutilisation de modules. Nous présentons l'ontologie modulaire MEMORAe-core 2 et nous montrons l'intégration de modules externes dans ce modèle. Nous proposons une méthode générique pour l'intégration de modules ontologiques ayant une structure particulière. Nous donnons l'exemple de l'intégration de modules dans une ontologie, modèle des ressources d'une TPE.

  20. La conception incrémentale de jeux sérieux musicaux pour la santé : théorie et application au traitement des troubles du comportement et de la maladie d'Alzheimer

    OpenAIRE

    Benveniste, Samuel

    2010-01-01

    Le jeu sérieux pour la santé (ludicament) est un domaine en pleine expansion dont les acteurs se proposent de rendre la prise en charge médicale plus motivante en y introduisant du "fun". De même, la musicothérapie encourage la recherche du "fun" musical et est de plus en plus plébiscitée par soignants et patients, notamment dans le cadre du traitement des troubles du comportement (Autisme, troubles limites...) et des maladies neuro-dégénératives (Alzheimer, Parkinson...). Pour profiter des s...

  1. Disposable chemical sensors and biosensors made on cellulose paper

    International Nuclear Information System (INIS)

    Most sensors are based on ceramic or semiconducting substrates, which have no flexibility or biocompatibility. Polymer-based sensors have been the subject of much attention due to their ability to collect molecules on their sensing surface with flexibility. Beyond polymer-based sensors, the recent discovery of cellulose as a smart material paved the way to the use of cellulose paper as a potential candidate for mechanical as well as electronic applications such as actuators and sensors. Several different paper-based sensors have been investigated and suggested. In this paper, we review the potential of cellulose materials for paper-based application devices, and suggest their feasibility for chemical and biosensor applications. (topical review)

  2. Cellulose Derivatives for Water Repellent Properties

    Science.gov (United States)

    In this poster presentation, we will discuss the synthesis and structural characterizations of nitro-benzyl cellulose (1), amino-benzyl cellulose (2) and pentafluoro –benzyl cellulose (3). All cellulose derivatives are synthesized by etherification process in lithium chloride/N,N-dimethylacetamide h...

  3. Cellulose synthase complexes: structure and regulation

    Directory of Open Access Journals (Sweden)

    Lei eLei

    2012-04-01

    Full Text Available This review is to update the most recent progress on characterization of the composition, regulation, and trafficking of cellulose synthase complexes. We will highlight proteins that interact with cellulose synthases, e.g. cellulose synthase-interactive protein 1 (CSI1. The potential regulation mechanisms by which cellulose synthase interact with cortical microtubules in primary cell walls will be discussed.

  4. Pharmaceutical significance of cellulose: A review

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available The amalgamation of polymer and pharmaceutical sciences led to the introduction of polymer in the design and development of drug delivery systems. Polymeric delivery systems are mainly intended to achieve controlled or sustained drug delivery. Polysaccharides fabricated into hydrophilic matrices remain popular biomaterials for controlled-release dosage forms and the most abundant naturally occurring biopolymer is cellulose; so hdroxypropylmethyl cellulose, hydroxypropyl cellulose, microcrystalline cellulose and hydroxyethyl cellulose can be used for production of time controlled delivery systems. Additionally microcrystalline cellulose, sodium carboxymethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose as well as hydroxypropyl cellulose are used to coat tablets. Cellulose acetate phthalate and hydroxymethyl cellulose phthalate are also used for enteric coating of tablets. Targeting of drugs to the colon following oral administration has also been accomplished by using polysaccharides such as hdroxypropylmethyl cellulose and hydroxypropyl cellulose in hydrated form; also they act as binders that swell when hydrated by gastric media and delay absorption. This paper assembles the current knowledge on the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for pharmaceuticals.

  5. Perichromism: a powerful tool for probing the properties of cellulose and its derivatives.

    Science.gov (United States)

    Fidale, Ludmila C; Heinze, Thomas; El Seoud, Omar A

    2013-03-01

    This overview is concerned with the use of certain dyes (perichromic indicators, hereafter designated as "probes") in order to determine the properties of cellulose, its solutions and solid derivatives. It is arranged as follows: (i) the properties of cellulose and its derivatives that are relevant to their applications are listed; (ii) a general discussion is presented on how perichromism can be employed in order to gain information on the medium where the probe is present; (iii) the results of perichromism, as applied to cellulose, cellulose solutions, and derivative films are discussed. PMID:23465911

  6. Extraction of Cellulose from Kepok Banana Peel (Musa parasidiaca L.) for Adsorption Procion Dye

    OpenAIRE

    Poedji Loekitowati Hariani; Fahma Riyanti; Riski Dita Asmara

    2016-01-01

    The aim of the research was to extract a cellulose from kepok banana peel (Musa parasidiaca L.) and application to removal Procion dye. The extracted cellulose was prepared by dewaxing process to releasing of lignin, bleaching and hemicellulose removal. The cellulose identified by FTIR and SEM-EDS. The efficiency of the cellulose to adsorp Procion dye was evaluated by variation in the initial concentration of dye (5, 10, 15, 20, 25, 30, 35, 40, 45 and 50 mg/L), solution pH (3, 4, 5, 6, 7, 8 a...

  7. Visualization of Nanofibrillar Cellulose in Biological Tissues Using a Biotinylated Carbohydrate Binding Module of β-1,4-Glycanase.

    Science.gov (United States)

    Knudsen, Kristina Bram; Kofoed, Christian; Espersen, Roall; Højgaard, Casper; Winther, Jakob Rahr; Willemoës, Martin; Wedin, Irene; Nuopponen, Markus; Vilske, Sara; Aimonen, Kukka; Weydahl, Ingrid Elise Konow; Alenius, Harri; Norppa, Hannu; Wolff, Henrik; Wallin, Håkan; Vogel, Ulla

    2015-08-17

    Nanofibrillar cellulose is a very promising innovation with diverse potential applications including high quality paper, coatings, and drug delivery carriers. The production of nanofibrillar cellulose on an industrial scale may lead to increased exposure to nanofibrillar cellulose both in the working environment and the general environment. Assessment of the potential health effects following exposure to nanofibrillar cellulose is therefore required. However, as nanofibrillar cellulose primarily consists of glucose moieties, detection of nanofibrillar cellulose in biological tissues is difficult. We have developed a simple and robust method for specific and sensitive detection of cellulose fibers, including nanofibrillar cellulose, in biological tissue, using a biotinylated carbohydrate binding module (CBM) of β-1,4-glycanase (EXG:CBM) from the bacterium Cellulomonas fimi. EXG:CBM was expressed in Eschericia coli, purified, and biotinylated. EXG:CBM was shown to bind quantitatively to five different cellulose fibers including four different nanofibrillar celluloses. Biotinylated EXG:CBM was used to visualize cellulose fibers by either fluorescence- or horse radish peroxidase (HRP)-tagged avidin labeling. The HRP-EXG:CBM complex was used to visualize cellulose fibers in both cryopreserved and paraffin embedded lung tissue from mice dosed by pharyngeal aspiration with 10-200 μg/mouse. Detection was shown to be highly specific, and the assay appeared very robust. The present method represents a novel concept for the design of simple, robust, and highly specific detection methods for the detection of nanomaterials, which are otherwise difficult to visualize. PMID:26208679

  8. Synthetic diamond devices for medical dosimetry applied to radiotherapy; Etude et developpement de dispositifs en diamant synthetique pour la dosimetrie medicale: applications en radiotherapie

    Energy Technology Data Exchange (ETDEWEB)

    Descamps, C

    2007-06-15

    The aim of this thesis, lead in the framework of an integrated European project entitled M.A.E.S.T.R.O. for ' Methods and Advanced Equipment for Simulation and Treatment in Radio Oncology', was to develop and test synthetic diamond detector in clinical environment for new modalities used in radiotherapy. Diamond is a good candidate for the detection of high energy beams in medical fields. It can be used for passive dosimetry, as thermoluminescent dosimeters or for active dosimetry as ionisation chambers. These two applications are presented here. Concerning the thermoluminescence, several impurities or dopants (boron, phosphorus, and nitrogen) have been incorporated in the diamond films during growth, in order to modify the material dosimetric properties and a detailed study of nitrogen-containing films is proposed. The second part presents the results obtained in active dosimetry. Two guide lines were followed: the measurement set-up optimisation and the material modification. The first dosimetric studies under radiotherapy beams concerning nitrogen-containing polycrystalline diamond as well as high purity single crystal diamond are conclusive. The detectors behaviours are in agreement with the recommendations of the International Atomic Energy Agency (IAEA). (author)

  9. Control of Glossina austeni and cattle trypanosomiasis in Unjuga island by deltamethrin pour-on application to livestock and with stationary targets in cattle-free zones

    International Nuclear Information System (INIS)

    Tsetse control with odour-baited artificial targets has been widely used in recent years in countries like Zimbabwe, Zambia, Ethiopia, Ivory Coast and Burkina Faso among others. More recently, this method was expanded by the use of the host animal itself, as a ''living target''. The development of highly effective synthetic pyrethroids in long-lasting formulations, and particularly the low mammalian toxicity of these compounds, made such an approach possible. The first trials have been carried out in Zimbabwe, Zambia, Zanzibar and recently at Mkwaja Ranch in Tanzania. Results achieved with FAO assistance in a pilot-trial in the Mangapwani area on Zanzibar have been converted into a large-scale operation under the UNDP/FAO supported project URT/86/022, aiming at complete removal of G, austeni from the island of Unjuga. The present paper outlines the results achieved so far with the use of sequential, topical application of deltamethrin on cattle, goats and donkeys to eradicate G. austeni. An alternative approach for tsetse control in areas where cattle are virtually absent is also described. (author). 12 refs, 2 tabs

  10. Thermophilic degradation of cellulosic biomass

    Science.gov (United States)

    Ng, T.; Zeikus, J. G.

    1982-12-01

    The conversion of cellulosic biomass to chemical feedstocks and fuel by microbial fermentation is an important objective of developing biotechnology. Direct fermentation of cellulosic derivatives to ethanol by thermophilic bacteria offers a promising approach to this goal. Fermentations at elevated temperatures lowers the energy demand for cooling and also facilitates the recovery of volatile products. In addition, thermophilic microorganisms possess enzymes with greater stability than those from mesophilic microorganisms. Three anaerobic thermophilic cocultures that ferment cellulosic substrate mainly to ethanol have been described: Clostridium thermocellum/Clostriidium thermohydrosulfuricum, C. thermocellum/Clostridium thermosaccharolyticum, and C. thermocellum/Thermoanaerobacter ethanolicus sp. nov. The growth characteristics and metabolic features of these cocultures are reviewed.

  11. Drying of Pigment-Cellulose Nanofibril Substrates

    Directory of Open Access Journals (Sweden)

    Oleg Timofeev

    2014-10-01

    Full Text Available A new substrate containing cellulose nanofibrils and inorganic pigment particles has been developed for printed electronics applications. The studied composite structure contains 80% fillers and is mechanically stable and flexible. Before drying, the solids content can be as low as 20% due to the high water binding capacity of the cellulose nanofibrils. We have studied several drying methods and their effects on the substrate properties. The aim is to achieve a tight, smooth surface keeping the drying efficiency simultaneously at a high level. The methods studied include: (1 drying on a hot metal surface; (2 air impingement drying; and (3 hot pressing. Somewhat surprisingly, drying rates measured for the pigment-cellulose nanofibril substrates were quite similar to those for the reference board sheets. Very high dewatering rates were observed for the hot pressing at high moisture contents. The drying method had significant effects on the final substrate properties, especially on short-range surface smoothness. The best smoothness was obtained with a combination of impingement and contact drying. The mechanical properties of the sheets were also affected by the drying method and associated temperature.

  12. Printed optically transparent graphene cellulose electrodes

    Science.gov (United States)

    Sinar, Dogan; Knopf, George K.; Nikumb, Suwas; Andrushchenko, Anatoly

    2016-02-01

    Optically transparent electrodes are a key component in variety of products including bioelectronics, touch screens, flexible displays, low emissivity windows, and photovoltaic cells. Although highly conductive indium tin oxide (ITO) films are often used in these electrode applications, the raw material is very expensive and the electrodes often fracture when mechanically stressed. An alternative low-cost material for inkjet printing transparent electrodes on glass and flexible polymer substrates is described in this paper. The water based ink is created by using a hydrophilic cellulose derivative, carboxymethyl cellulose (CMC), to help suspend the naturally hydrophobic graphene (G) sheets in a solvent composed of 70% DI water and 30% 2-butoxyethanol. The CMC chain has hydrophobic and hydrophilic functional sites which allow adsorption on G sheets and, therefore, permit the graphene to be stabilized in water by electrostatic and steric forces. Once deposited on the functionalized substrate the electrical conductivity of the printed films can be "tuned" by decomposing the cellulose stabilizer using thermal reduction. The entire electrode can be thermally reduced in an oven or portions of the electrode thermally modified using a laser annealing process. The thermal process can reduce the sheet resistance of G-CMC films to high optical transparency.

  13. Application de l'A.D.L, pour la mesure du champ de vitesses instationnaires de llecoulement a Ilechappement d'un moteur a combustion interne

    Science.gov (United States)

    Boutrif, M. S.; Thelliez, M.

    1993-01-01

    We present experimental results of instantaneous velocity measurement, which were obtained by application of the laser Doppler anemometry (L.D.A.) at the exhaust pipe of a reciprocating engine under real working conditions. First of all, we show that the instantaneous velocity is monodimensional along a straight exhaust pipe, and that the boundary layer develops within a 2mm thickness. We also show that the cylinder discharges in two phases : the blow down period and the final part of exhaust stroke. We also make obvious, that the flow escapes very quickly : its velocity varies between - 100m/s and 200m/s within a period shorter than 1ms ; thereby, we do record the acoustic resonance phenomenon, when the engine speed is greater than 3 000rpm. Finally, we show that in the exhaust pipe the apparent fluctuation - i.e. the cyclic dispersion and the actual turbulence - may reach 15%. Nous présentons des résultats expérimentaux du champ de vitesses instationnaires, obtenus par adaptation et application de la vélocimétrie laser interférentielle communément appelée à effet Doppler (L.D.A.), à l'échappement d'un moteur altematif à combustion inteme en fonctionnement nominal. Tout d'abord, nous montrons que dans un tube d'échappement long et droit, la vitesse instantanée est bien monodimensionnelle et que l'écoulement occupe la quasitotalité de la section droite géométrique du tube (une couche limite d'épaisseur inférieure à 2mm se développe très près de la paroi du tube). Nous pouvons également décrire la vidange du cylindre du moteur étudié en deux phases principales : bouffée d'échappement et refoulement des gaz brûlés par le piston. Nous mettons de même en évidence l'état très pulsé de l'écoulement, puisqu'en un intervalle de temps inférieur à 1ms, la vitesse de l'écoulement varie de - 100m/s à 200m/s ; nous enregistrons ainsi l'apparition du phénomène de résonance acoustique à des vitesses de rotation supérieures à 3 500

  14. PENYALUTAN KACANG RENDAH LEMAK MENGGUNAKAN SELULOSA ETER DENGAN PENCELUPAN UNTUK MENGURANGI PENYERAPAN MINYAK SELAMA PENGGORENGAN DAN MENINGKATKAN STABILITAS OKSIDATIF SELAMA PENYIMPANAN [Ether Cellulose Coatings by Dipping on Partially Defatted Peanuts to Reduce Oil Uptake During Frying and to Increase Oxidative Stability During Storage

    OpenAIRE

    Made Darawati1); Yudi Pranoto2)

    2010-01-01

    This research aimed to reduce oil uptake during frying and to improve the oxidative stability of a partially defatted peanuts (PDP) product by coating with ether cellulose-based substances, namely carboxymethyl cellulose (CMC), hydroxyprophyl methyl cellulose (HPMC), methyl cellulose (MC) and hydroxyprophyl cellulose by dipping method. The research was conducted through following steps: preparation of ether cellulose-based edible film and evaluation of the properties, coating application on P...

  15. Characterization of Cellulose Synthesis in Plant Cells

    OpenAIRE

    Samaneh Sadat Maleki; Kourosh Mohammadi; Kong-shu Ji

    2016-01-01

    Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4) D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC) from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA) proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the...

  16. Cellulose membrane as a biomaterial: from hydrolysis to depolymerization with electron beam.

    Science.gov (United States)

    Eo, Mi Young; Fan, Huan; Cho, Yun Ju; Kim, Soung Min; Lee, Suk Keun

    2016-01-01

    The cellulose membrane (CM) is a major component of plant cell walls and is both a chemically and mechanically stable synthetic polymer with many applications for use in tissue engineering. However, due to its dissolution difficulty, there are no known physiologically relevant or pharmaceutically clinical applications for this polymer. Thus, research is underway on controlled and adjusted forms of cellulose depolymerization. To advance the study of applying CM for tissue engineering, we have suggested new possibilities for electron beam (E-beam) treatment of CM. Treatment of CM with an E-beam can modify physical, chemical, molecular and biological properties, so it can be studied continuously to improve its usefulness and to enhance value. We review clinical applications of CM, cellulose binding domains, cellulose crosslinking proteins, conventional hydrolysis of cellulose, and depolymerization with radiation and focus our experiences with depolymerization of E-beam irradiated CM in this article. PMID:27418974

  17. Heterogenous iodination of α-cellulose: preparation of a radioactive analog of dietary fiber

    International Nuclear Information System (INIS)

    α-Cellulose has been iodinated by a method which yields a chemically stable iodinated cellulose of high specific activity. The preparation and chemical stability of the derivative are described, together with potential application as a tracer for the study of digestion and as an imaging agent in the digestive tract. (author)

  18. PRETREATMENT AND SUBSTRATE EVALUATION FOR THE ENZYMATIC HYDROLYSIS OF CELLULOSIC WASTES

    Science.gov (United States)

    Presented are initial studies aimed at determining the applicability of various pretreatment methods and existing cellulosic wastes to a process for the conversion of cellulose to glucose and other reducing sugars. In this process, a cellulase from a mutant of Trichoderma viride ...

  19. Hydrogen peroxide production from fibrous pectic cellulose analogs and effect on dermal fibroblasts

    Science.gov (United States)

    Naturally derived products with folklore remedies have in recent years been reconsidered for their benefit to wound healing i.e., honey’s application to chronic wound dressing products. Similarly, we have undertaken an evaluation of Fibrous pectin-cellulose (FPC) (cellulose blended with primary cel...

  20. 40 CFR 80.1456 - What are the provisions for cellulosic biofuel waiver credits?

    Science.gov (United States)

    2010-07-01

    ... biofuel waiver credits? 80.1456 Section 80.1456 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... What are the provisions for cellulosic biofuel waiver credits? (a) If EPA reduces the applicable volume of cellulosic biofuel pursuant to section 211(o)(7)(D)(i) of the Clean Air Act (42 U.S.C....

  1. Chromophores in lignin-free cellulosic materials belong to three compound classes. Chromophores in cellulosics, XII

    Science.gov (United States)

    The CRI (chromophore release and identification) method isolates well-defined chromophoric substances from different cellulosic matrices, such as highly bleached pulps, cotton linters, bacterial cellulose, viscose or lyocell fibers, and cellulose acetates. The chromophores are present only in extrem...

  2. Bacterial cellulose/boehmite composites

    Energy Technology Data Exchange (ETDEWEB)

    Salvi, Denise T.B. de; Barud, Hernane S.; Messaddeq, Younes; Ribeiro, Sidney J.L. [Universidade Estadual Paulista Julio de Mesquita Filho. UNESP. Instituto de Quimica de Araraquara, SP (Brazil); Caiut, Jose Mauricio A. [Universidade de Sao Paulo. Departamento de Quimica - FFCLRP/USP, Ribeirao Preto, SP (Brazil)

    2011-07-01

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  3. Bacterial cellulose/boehmite composites

    International Nuclear Information System (INIS)

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  4. Processing and study of properties of films and injected pieces of nanobiocomposites of cellulose whiskers and biodegradable polymers

    OpenAIRE

    Morelli, Carolina Lipparelli

    2014-01-01

    This study aimed at evaluating the potential of application of cellulose nanocrystals as reinforcing elements of biodegradable polymeric matrices, in the films and injection molded pieces applications. Two polymeric matrices with different properties were used, namely: poly(butylene adipate-co-terephthalate), PBAT, and poly(lactic acid), PLA. For the extraction of cellulose nanocrystals (NCC), two sources were selected: microcrystalline cellulose (CMC) and balsa wood . Due to the high polarit...

  5. Preparation and application of cellulose acetate/Fe films in the degradation of Reactive Black 5 dye through photo-Fenton reaction.

    Science.gov (United States)

    Ribeiro, Karine; de Andrade, Tamara Maria; Fujiwara, Sérgio Toshio

    2016-07-01

    In this study, the Reactive Black 5 dye degradation and textile effluent were investigated using the photo-Fenton process employing immobilized Fe(3+) in acetate cellulose films. The films prepared were characterized through Fourier transform infrared spectroscopy, atomic absorption spectroscopy, scanning electron microscopy - energy-dispersive spectroscopy and ultraviolet visible spectroscopy. The factorial design revealed that the best conditions for the Reactive Black 5 dye degradation were obtained using the film containing 5% Fe (w/w), 100 mg L(-1) H2O2 and pH 4.0. In studies using artificial light, the dye degradation was 99.29% and the chemical oxygen demand (COD) reduction was 90% after 45 min of treatment. In the process assisted by sunlight, the degradation was 86% and the COD reduction was 70% considering the same time of treatment. At pH 6.0 and artificial light, the dye degradation was 98.90% and the COD reduction was 78%, indicating that the material prepared can be used at pH values greater than 3 without the occurrence of hydrated ferric oxides precipitation. It was also observed that the material can be reused seven consecutive times without substantial loss of efficacy in dye degradation. Furthermore, the proposed material reduces the COD of a textile effluent by 72% after 300 min of treatment. PMID:26675986

  6. Immobilization of β-glucosidase from Aspergillus niger on κ-carrageenan hybrid matrix and its application on the production of reducing sugar from macroalgae cellulosic residue.

    Science.gov (United States)

    Tan, Inn Shi; Lee, Keat Teong

    2015-05-01

    A novel concept for the synthesis of a stable polymer hybrid matrix bead was developed in this study. The beads were further applied for enzyme immobilization to produce stable and active biocatalysts with low enzyme leakage, and high immobilization efficiency, enzyme activity, and recyclability. The immobilization conditions, including PEI concentration, activation time and pH of the PEI solution were investigated and optimized. All formulated beads were characterized for its functionalized groups, composition, surface morphology and thermal stability. Compared with the free β-glucosidase, the immobilized β-glucosidase on the hybrid matrix bead was able to tolerate broader range of pH values and higher reaction temperature up to 60 °C. The immobilized β-glucosidase was then used to hydrolyse pretreated macroalgae cellulosic residue (MCR) for the production of reducing sugar and a hydrolysis yield of 73.4% was obtained. After repeated twelve runs, immobilized β-glucosidase retained about 75% of its initial activity. PMID:25465785

  7. Cellulose biosynthesis in Acetobacter xylinum

    International Nuclear Information System (INIS)

    Time-lapse video microscopy has shown periodic reversals during the synthesis of cellulose. In the presence of Congo Red, Acetobacter produces a band of fine fibrils. The direction of cell movement is perpendicular to the longitudinal axis of cell, and the rate of movement was decreased. A linear row of particles, presumably the cellulose synthesizing complexes, was found on the outer membrane by freeze-fracture technique. During the cell cycle, the increase of particles in linear row, the differentiation to four linear rows and the separation of the linear rows have been observed. A digitonin-solubilized cellulose synthase was prepared from A. xylinum, and incubated under conditions known to lead to active in vitro synthesis of 1,4-β-D-glucan polymer. Electron microscopy revealed that clusters of fibrils were assembled within minutes. Individual fibrils are 17 ± 2 angstroms in diameter. Evidence for the cellulosic composition of newly synthesized fibrils was based on incorporation of tritium from UDP-[3H] glucose binding of gold-labeled cellobiohydrolase, and an electron diffraction pattern identified as cellulose II polymorph instead of cellulose I

  8. Fluorescent cellulose nanocrystals via supramolecular assembly of terpyridine-modified cellulose nanocrystals and terpyridine-modified perylene

    International Nuclear Information System (INIS)

    Highlights: ► Surfaces of cellulose nanocrystals were modified with terpyridine ligands. ► Fluorescent nanocrystals could be obtained via self-assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals. ► Further self-assembly of azide-functionalized terpyridine onto the fluorescent cellulose nanocrystals was possible to obtain nanocellulosic material with expected use in bioimaging. - Abstract: Due to their natural origin, biocompatibility, and non-toxicity, cellulose nanocrystals are promising candidates for applications in nanomedicine. Highly fluorescent nanocellulosic material was prepared via surface modification of cellulose nanocrystals with 2,2′:6′,2″-terpyridine side chains followed by supramolecular assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals (CTP) via RuIII/RuII reduction. The prepared terpyridine-modified cellulose-RuII-terpyridine-modified perylene (CTP-RuII-PeryTP) fluorescent nanocrystals were characterized using cross-polarized/magic angle spin 13C nuclear magnetic resonance (CP/MAS 13C NMR), Fourier transform infrared (FTIR), UV–visible, and fluorescence spectroscopy. In addition, further self-assembly of terpyridine units with azide functional groups onto CTP-RuII-PeryTP was possible via repeating the RuIII/RuII reduction protocol to prepare supramolecular fluorescent nanocrystals with azide functionality (CTP-RuII-PeryTP-RuII-AZTP). The prepared derivative may have potential application in bio-imaging since the terminal azide groups can be easily reacted with antigens via “Click” chemistry reaction.

  9. Fluorescent cellulose nanocrystals via supramolecular assembly of terpyridine-modified cellulose nanocrystals and terpyridine-modified perylene

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Mohammad L., E-mail: mlhassan2004@yahoo.com [Cellulose and Paper Department and Center of Excellence for Advanced Sciences, Advanced Materials and Nanotechnology Group, National Research Center, Dokki, Cairo 12622 (Egypt); Moorefield, Charles M.; Elbatal, Hany S. [Maurice Morton Institute for Polymer Science, University of Akron, Akron, OH 44325 (United States); Newkome, George R. [Maurice Morton Institute for Polymer Science, University of Akron, Akron, OH 44325 (United States); Departments of Polymer Science and Chemistry, University of Akron, Akron, OH 44325 (United States); Modarelli, David A.; Romano, Natalie C. [Department of Chemistry and The Center for Laser and Optical Spectroscopy, University of Akron, Akron, OH 44325 (United States)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Surfaces of cellulose nanocrystals were modified with terpyridine ligands. Black-Right-Pointing-Pointer Fluorescent nanocrystals could be obtained via self-assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals. Black-Right-Pointing-Pointer Further self-assembly of azide-functionalized terpyridine onto the fluorescent cellulose nanocrystals was possible to obtain nanocellulosic material with expected use in bioimaging. - Abstract: Due to their natural origin, biocompatibility, and non-toxicity, cellulose nanocrystals are promising candidates for applications in nanomedicine. Highly fluorescent nanocellulosic material was prepared via surface modification of cellulose nanocrystals with 2,2 Prime :6 Prime ,2 Double-Prime -terpyridine side chains followed by supramolecular assembly of terpyridine-modified perylene dye onto the terpyridine-modified cellulose nanocrystals (CTP) via Ru{sup III}/Ru{sup II} reduction. The prepared terpyridine-modified cellulose-Ru{sup II}-terpyridine-modified perylene (CTP-Ru{sup II}-PeryTP) fluorescent nanocrystals were characterized using cross-polarized/magic angle spin {sup 13}C nuclear magnetic resonance (CP/MAS {sup 13}C NMR), Fourier transform infrared (FTIR), UV-visible, and fluorescence spectroscopy. In addition, further self-assembly of terpyridine units with azide functional groups onto CTP-Ru{sup II}-PeryTP was possible via repeating the Ru{sup III}/Ru{sup II} reduction protocol to prepare supramolecular fluorescent nanocrystals with azide functionality (CTP-Ru{sup II}-PeryTP-Ru{sup II}-AZTP). The prepared derivative may have potential application in bio-imaging since the terminal azide groups can be easily reacted with antigens via 'Click' chemistry reaction.

  10. High-yield production of extracellular type-I cellulose by the cyanobacterium Synechococcus sp. PCC 7002.

    Science.gov (United States)

    Zhao, Chi; Li, Zhongkui; Li, Tao; Zhang, Yingjiao; Bryant, Donald A; Zhao, Jindong

    2015-01-01

    Cellulose synthase, encoded by the cesA gene, is responsible for the synthesis of cellulose in nature. We show that the cell wall of the cyanobacterium Synechococcus sp. PCC 7002 naturally contains cellulose. Cellulose occurs as a possibly laminated layer between the inner and outer membrane, as well as being an important component of the extracellular glycocalyx in this cyanobacterium. Overexpression of six genes, cmc-ccp-cesAB-cesC-cesD-bgl, from Gluconacetobacter xylinus in Synechococcus sp. PCC 7002 resulted in very high-yield production of extracellular type-I cellulose. High-level cellulose production only occurred when the native cesA gene was inactivated and when cells were grown at low salinity. This system provides a method for the production of lignin-free cellulose from sunlight and CO2 for biofuel production and other biotechnological applications. PMID:27462405

  11. Occurrence of Cellulose-Producing Gluconacetobacter spp. in Fruit Samples and Kombucha Tea, and Production of the Biopolymer.

    Science.gov (United States)

    Neera; Ramana, Karna Venkata; Batra, Harsh Vardhan

    2015-06-01

    Cellulose producing bacteria were isolated from fruit samples and kombucha tea (a fermented beverage) using CuSO4 solution in modified Watanabe and Yamanaka medium to inhibit yeasts and molds. Six bacterial strains showing cellulose production were isolated and identified by 16S rRNA gene sequencing as Gluconacetobacter xylinus strain DFBT, Ga. xylinus strain dfr-1, Gluconobacter oxydans strain dfr-2, G. oxydans strain dfr-3, Acetobacter orientalis strain dfr-4, and Gluconacetobacter intermedius strain dfr-5. All the cellulose-producing bacteria were checked for the cellulose yield. A potent cellulose-producing bacterium, i.e., Ga. xylinus strain DFBT based on yield (cellulose yield 5.6 g/L) was selected for further studies. Cellulose was also produced in non- conventional media such as pineapple juice medium and hydrolysed corn starch medium. A very high yield of 9.1 g/L cellulose was obtained in pineapple juice medium. Fourier transform infrared spectrometer (FT-IR) analysis of the bacterial cellulose showed the characteristic peaks. Soft cellulose with a very high water holding capacity was produced using limited aeration. Scanning electron microscopy (SEM) was used to analyze the surface characteristics of normal bacterial cellulose and soft cellulose. The structural analysis of the polymer was performed using (13)C solid-state nuclear magnetic resonance (NMR). More interfibrillar space was observed in the case of soft cellulose as compared to normal cellulose. This soft cellulose can find potential applications in the food industry as it can be swallowed easily without chewing. PMID:25926011

  12. Opportunity for profitable investments in cellulosic biofuels

    International Nuclear Information System (INIS)

    Research efforts to allow large-scale conversion of cellulose into biofuels are being undertaken in the US and EU. These efforts are designed to increase logistic and conversion efficiencies, enhancing the economic competitiveness of cellulosic biofuels. However, not enough attention has been paid to the future market conditions for cellulosic biofuels, which will determine whether the necessary private investment will be available to allow a cellulosic biofuels industry to emerge. We examine the future market for cellulosic biofuels, differentiating between cellulosic ethanol and 'drop-in' cellulosic biofuels that can be transported with petroleum fuels and have equivalent energy values. We show that emergence of a cellulosic ethanol industry is unlikely without costly government subsidies, in part because of strong competition from conventional ethanol and limits on ethanol blending. If production costs of drop-in cellulosic biofuels fall enough to become competitive, then their expansion will not necessarily cause feedstock prices to rise. As long as local supplies of feedstocks that have no or low-valued alternative uses exist, then expansion will not cause prices to rise significantly. If cellulosic feedstocks come from dedicated biomass crops, then the supply curves will have a steeper slope because of competition for land. - Research highlights: → The likelihood of a significant cellulosic ethanol industry in the US looks dim. → Drop-in biofuels made from cellulosic feedstocks have a more promising future. → The spatial dimension of markets for cellulosic feedstocks will be limited. → Corn ethanol will be a tough competitor for cellulosic ethanol.

  13. Electrospun cellulose nitrate and polycaprolactone blended nanofibers

    Science.gov (United States)

    Nartker, Steven; Hassan, Mohamed; Stogsdill, Michael

    2015-03-01

    Pure cellulose nitrate (CN) and blends of CN and polycaprolactone were electrospun to form nonwoven mats. Polymers were dissolved in a mixed solvent system of tetrahydrofuran and N,N-dimethylformamide. The concentrations were varied to obtain sub-micron and nanoscale fiber mats. Fiber mats were analyzed using scanning electron microscopy, contact angle analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The fiber morphology, surface chemistry and contact angle data show that these electrospun materials are suitable for applications including biosensing, biomedical and tissue engineering.

  14. Endommagement des aciers TWIP pour application automobile

    OpenAIRE

    Lorthios, Julie

    2011-01-01

    Co-encadrement de la thèse : Matthieu Mazière Ultra high strength Fe-Mn-C Twinning Induced Plasticity (TWIP) austenitic steels exhibit excellent formability for automotive safety parts. By refining the microstructure during straining, deformation twinning induces a high hardening rate and provides high ultimate tensile strength (>1000MPa) combined with excellent ductility (>50%). However, plastic instabilities and TWIP effect lead to atypical failures modes and standard forming limit curve...

  15. Cellulose nanofibrils improve the properties of all-cellulose composites by the nano-reinforcement mechanism and nanofibril-induced crystallization

    Science.gov (United States)

    Yang, Quanling; Saito, Tsuguyuki; Berglund, Lars A.; Isogai, Akira

    2015-10-01

    All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials.All-cellulose nanocomposite films containing crystalline TEMPO-oxidized cellulose nanofibrils (TOCNs) of 0-1 wt% were fabricated by mixing aqueous TOCN dispersions with alkali/urea/cellulose (AUC) solutions at room temperature. The mixtures were cast on glass plates, soaked in an acid solution, and the regenerated gel-like films were washed with water and then dried. The TOCN did not form agglomerates in the composites, and had the structure of TOCN-COOH, forming hydrogen bonds with the hydroxyl groups of the regenerated cellulose molecules. X-ray diffraction analysis revealed that the matrix cellulose molecules increased the cellulose II crystal size upon incorporation of TOCN. As a result, the TOCN/AUC composite films had high Young's modulus, tensile strength, thermal stability and oxygen-barrier properties. The TOCN/AUC composite films are promising all-cellulose nanocomposites for versatile applications as new bio-based materials. Electronic supplementary information (ESI) available: Fig. S1-S3 show an AFM image of TOCN, SEM

  16. Elaboration et caractérisation d'alliages de type Ti-Nb-X (X = O, N pour des applications biomédicales Synthesis and characterisation of Ti-Nb-X (X = O, N alloys for biomedical application

    Directory of Open Access Journals (Sweden)

    Ramarolahy A.

    2013-11-01

    Full Text Available Dans cette étude, trois alliages de titane β-métastables de composition Ti-27Nb, Ti-24Nb-0.5N et Ti-24Nb-0.5O ont été élaborés par fusion. Ces trois alliages présentent des propriétés superélastiques lors des essais de traction. Des essais de traction in-situ sous rayonnement synchrotron nous ont permis de monter que cette superélasticité est due à une transformation martensitique réversible β → α” bien connue pour deux alliages alors que celui contenant de l'oxygène présente un comportement moins conventionnel. Les températures caractéristiques (MS, MF de la transformation martensitique β (austénite vers α” (martensite et celles (AS, AF de la transformation inverse α” vers β ont aussi été déterminées par des essais mécaniques dynamiques. Ces températures caractéristiques augmentent linéairement avec la contrainte externe et cette augmentation suit la relation de Clausius Clapeyron. Ti-Nb based alloys are well known to their good mechanical properties, shape memory effect, superelasticity, as well as good biocompatibility. Our study is focused on the improvement of their mechanical properties by adding alloying element such as oxygen or nitrogen. Superelasticity was drastically improved by addition of a few amount (0.5 at % of oxygen or nitrogen. Martensitic transformation between the β parent phase (austenite and α” product phase (martensite, responsible for the superelastic property, has been extensively studied by Dynamic Mechanical Analysis (DMA and in-situ tensile test under X-ray synchrotron diffraction.

  17. Mass spectrometer introduction line: application to the analysis of impurities in uranium hexafluoride; Ligne d'introduction pour spectrometre de masse: application a l'analyse des impuretes contenues dans l'UF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Besson, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Departement de physico-chimie, service des isotopes stables, section de spectrometrie de masse

    1967-01-01

    The continuous mass-spectrometric analysis of impurities in UF{sub 6} is possible industrially if certain conditions imposed by the nature of the gas are respected. The gas introduction line arriving at the spectrometer's source makes it possible to fix the flow-rate, to control the inlet pressure and to selectively destroy the gas containing the impurities. The operational conditions for the line are defined and a description is given of the theoretical and experimental study of the various elements of which it is composed, i.e. the leak valve, the flow-meter, the chemical trap and the servo-mechanism making it possible to regulate and control the gas flow. The dynamic characteristics of the line's various components and the performance of the equipment in the case of the analyses considered are given. (author) [French] L'analyse en continu par spectrometrie de masse des impuretes contenus dans l'UF{sub 6} est possible industriellement moyennant certaines conditions imposees par la nature du gaz. La ligne d'introduction des gaz dans la source du spectrometre permet de regler le debit, de controler la pression d'introduction et de detruire selectivement le gaz porteur d'impuretes. Les conditions de fonctionnement de la ligne etant definies, on decrit l'etude theorique et experimentale des differents elements qui la composent, c'est-a-dire: le robinet a fuite, le debitmetre, le piege chimique et l'ensemble d'asservissement permettant la regulation et le controle du debit. On donne les caracteristiques dynamiques des differents constituants de la ligne et les performances de l'ensemble pour les analyses considerees. (auteur)

  18. Conception d'un CAN pipeline de très faible consommation pour capteurs monolithiques à pixels actifs en technologie CMOS dédié aux applications de physique de particules et imageries biomédicales

    OpenAIRE

    Dahoumane, M.; Dzahini, D.; Rossetto, O.; Bouvier, J.; Lagorio, E.; Hostachy, J.Y; Hu, Y.; Ghazlane, H.; Dallet, Dominique

    2007-01-01

    Un convertisseur analogique numérique (CAN) de type pipeline 5bits, de faible consommation a été développé pour l'électronique de lecture des détecteurs monolithiques à pixels actifs en technologie CMOS. Le convertisseur inclut un échantillonneur bloqueur de gain 4 suivi de trois étages pipelines de 1.5bit et d'un dernier étage flash 2bits. La fréquence maximale est de 25Mhz. La puissance totale dissipée est de 1.7 mW/canal pour une tension d'alimentation typique de 3.3V. La taille du CAN est...

  19. Une méthodologie de modélisation par processus multiples et incrémentiels : application pour l'évaluation des performances de la Supply Chain

    OpenAIRE

    Féniès, Pierre

    2006-01-01

    L'étude de la littérature montre que l'aide à la décision pour la Supply Chain (SC) ignore l'évaluation des flux financiers. Cette thèse propose une approche transdisciplinaire permettant l'évaluation des flux physiques et financiers de la SC. Nous proposons une méthodologie de modélisation par processus multiples et incrémentiels ainsi qu'un environnement de modélisation qui ont pour but d'évaluer flux physiques et financiers d'une SC. L'évaluation de la performance est réalisée par un modèl...

  20. Modèle d'architecture personnalisable pour l'optimisation de l'accès à des ressources et services pervasifs : Application à la télémédecine

    OpenAIRE

    Nageba, Ebrahim

    2011-01-01

    Le développement et l'usage croissants de systèmes pervasifs, dotés de fonctionnalités et de moyens de communication de plus en plus sophistiqués, offrent de fantastiques potentialités de services, en particulier pour l'e-Santé et la télémédecine, au bénéfice de tout citoyen, patient ou professionnel de santé. L'un des challenges sociétaux actuels est de permettre une meilleure exploitation des services disponibles pour l'ensemble des acteurs impliqués dans un domaine donné. Mais la multiplic...

  1. Approche multi-agent pour la multi-modélisation et le couplage de simulations. Application à l'étude des influences entre le fonctionnement des réseaux ambiants et le comportement de leurs utilisateurs.

    OpenAIRE

    Siebert, Julien

    2011-01-01

    Ce travail de thèse, mené sur deux thématiques : les réseaux ambiants et la simulation multi-agent, a pour contexte l'étude des interactions entre le fonctionnement des réseaux ambiants (réseaux pair-à-pair et réseaux mobiles ad hoc networks) et les comportements de leurs usagers (mobilité, partage d'un service, etc.). Pour étudier ces phénomènes, nous avons mis en lumière le besoin de réutiliser, de coupler et de faire interagir des outils de modélisation et de simulation provenant de domain...

  2. Microfibrillated cellulose: morphology and accessibility

    Energy Technology Data Exchange (ETDEWEB)

    Herrick, F.W.; Casebier, R.L.; Hamilton, J.K.; Sandberg, K.R.

    1983-01-01

    Microfibrillated cellulose (MFC) is prepared by subjecting dilute slurries of cellulose fibers to repeated high-pressure homogenizing action. A highly microfibrillated product will have a gel-like appearance at 2% concentration in water. Such gels have pseudoplastic viscosity properties and are very fluid when stirred at high shear rate. The relative viscosity of 2% MFC dispersions may be used as a measure of the degree of homogenization or microfibrillation of a given wood cellulose pulp. The water retention value of an MFC product can also be used as an indicator for degree of homogenization. Structurally, MFC appears to be a web of interconnected fibrils and microfibrils, the latter having diameters in the range 10-100 nm as observed in scanning and transmission electron micrographs. Chemical studies have revealed that MFC is only moderately degraded, while being greatly expanded in surface area. The accessibility of cellulose in MFC is only moderately degraded, while being greatly expanded in surface area. The accessibility of cellulose in MFC toward chemical reagents is greatly increased. Higher reactivity was demonstrated in dilute cupriethylenediamine solubility, triphenylmethylation, acetylation, periodate oxidation, and mineral acid and cellulase enzyme hydrolysis rates. 16 references, 8 figures, 7 tables.

  3. The World's Largest Steel Casting Poured Successfully

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The world's largest steel casting -- the upper beam (or the top head) for free forging oil hydraulic press with a 18,000-ton force capacity, was poured successfully by CITIC Heavy Machinery Co., Ltd. (CITICHM) on May 22, 2008. This head piece is 11.95 meters long, 3.8 meters wide, 4.59 meters high and about 520 tons in gross weight. Pouring is the most important and critical step during its manufacturing process. The production of this huge casting requires about 830 tons of refined molten steel from 10 smelting furnaces and pouring with six ladles into the mold cavity at one time, which made it currently the world's largest steel casting poured and the most one-time molten steel organized.

  4. Elucidating the Potential Biological Impact of Cellulose Nanocrystals

    Directory of Open Access Journals (Sweden)

    Sandra Camarero-Espinosa

    2016-07-01

    Full Text Available Cellulose nanocrystals exhibit an interesting combination of mechanical properties and physical characteristics, which make them potentially useful for a wide range of consumer applications. However, as the usage of these bio-based nanofibers increases, a greater understanding of human exposure addressing their potential health issues should be gained. The aim of this perspective is to highlight how knowledge obtained from studying the biological impact of other nanomaterials can provide a basis for future research strategies to deduce the possible human health risks posed by cellulose nanocrystals.

  5. Cellulose Nanocrystals as Water in Water Emulsion Stabilizers

    Science.gov (United States)

    Peddireddy, Karthik Reddy; Capron, Isabelle; Nicolai, Taco; Benyahia, Lazhar

    Cellulose is the most abundant polymer on the earth. Thus, it is very much desirable to find as many practical applications as possible for it. Cellulose, in its original form, contains both amorphous and crystalline parts. It is possible to separate both parts by dissolving the amorphous part in concentrated sulfuric acid. The remaining crystalline cellulose part exist in the form of rod-like particles. The dimensions of the particles depend on the source. We produce the particles from the acid hydrolysis of cotton cellulose fibers. It results in cellulose nanocrystals (CNCs) with dimensions of ~150 nm x 6 nm x 6 nm. It is well known that CNCs could very efficiently stabilize oil in water (O/W) emulsions by forming very dense monolayers of CNCs at O-W interfaces. However, it is not yet known whether they could also stabilize water in water (W/W) emulsions. The W/W emulsions can be produced by any two incompatible polymers. It is challenging to find effective stabilizers for W/W emulsions due to ultralow interfacial tension and large interfacial thickness. In this talk, I will show the efficiency and effectiveness of these one-dimensional rods as W/W emulsion stabilizers.

  6. UV-curable polyurethane coatings derived from cellulose

    International Nuclear Information System (INIS)

    At the present time coating industry is devoting much research in the direction of low volatile organic compounds to make eco-friendly coating material. In this study, such materials are developed from cellulose derived from bagasse, a sugar industry waste. Cellulose is converted to cellulose glyco glycoside by acid hydrolysis of cellulose under heterogeneous condition. Cellulose glyco glycoside is treated with polyethylene glycol having different molecular weights to give glyco glycosides which in turn are reacted with various diisocyanates to obtain polyurethane having free NCO groups. These materials are then reacted with hydroxyethylmethacrylate to give polyurethane acrylates. The acrylates are characterized for specific gravity, viscosity, colour and molecular weight as well as by fourier transform infrared spectroscopy. The UV-curable coating composition was prepared by blending PU-acrylate, reactive diluents and photoinitiator. Coating compositions were cured under UV-light and characterized for adhesion, flexibility, impact resistance, solvent resistance and for dynamic mechanical analysis as well as by thermal gravimetric analysis for thermal stability. The cured films give thickness of 23-24 microns and cure time required is less than 1.5-2.0 min. There is no liberation of any volatiles during curing and films have good adhesion to mild steel substrate. The cured coatings give excellent dynamic, mechanical and chemical properties. The scratch resistance was found to be satisfactory. The application was made in unpigmented form but it is found that various pigments can be used to give coloured UV-curable coatings.

  7. Extraction and Characterization of Nano cellulose from Coconut Fiber

    International Nuclear Information System (INIS)

    Coconut husk fibers has been modified by some chemical treatments to extract cellulose nano crystals (CNC), which are alkali treatment, bleaching and acid hydrolysis using concentrated sulphuric acid. The effect of the treatments on the coconut husk fibers has been analysed using Fourier transform infrared (FTIR) and X-Ray diffraction (XRD). Meanwhile, the morphology observation and thermal stability of the fiber have been analysed by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) respectively. The analyses show that the chemical modification could eliminate some of the lignin and hemicelluloses of the fiber. Nano cellulose extracted from acid hydrolysis has been analysed using transmission electron microscopy (TEM) to define the size of extracted nano cellulose. The cellulose nano crystals from coconut fibre has the average diameter and length in the range 13.7±6.2 nm and 172.3±8.4 nm, respectively. The obtained nano cellulose may have the potential applications in the fields of biomedical, oil adsorption, membrane, pharmaceutical and bio composites. (author)

  8. Development of cellulose derivatives for application as viscosity-enhancing agents in injection fluids for enhanced recovery of mineral oil. Entwicklung von Cellulosederivaten fuer den Einsatz als Viskositaetsbildner in Flutmedien fuer die verbesserte Erdoelfoerderung

    Energy Technology Data Exchange (ETDEWEB)

    Kniewske, R.

    1989-09-01

    Systematic variations of the reaction conditions, the substituent combinations and substitution levels, as well as the cellulose basis caused a series of product optimizations. Methylsulfoethyl cellulose (MSEC) and carboxymethyl sulfoethyl cellulose (CMSEC) come closest to the technical and economical requirements on enhanced recovery. The combination of polymeric characteristics with surfactant characteristics resulted in a specific behaviour of MSEC types in injection experiments. The multiple oil extraction rates were higher than with all other celllulose ethers and xanthane. The state of the art is surpassed with the types CMSEC and MSEC with regard to the injectivity and filtering characteristics. (orig./BBR).

  9. Regenerated bacterial cellulose microfluidic column for glycoproteins separation.

    Science.gov (United States)

    Chen, Chuntao; Zhu, Chunlin; Huang, Yang; Nie, Ying; Yang, Jiazhi; Shen, Ruiqi; Sun, Dongping

    2016-02-10

    To analysis and separate glycoproteins, a simple strategy to prepare regenerated bacterial cellulose (RBC) column with concanavalin A (Con A) lectin immobilized in microfluidic system was applied. RBC was filled into microchannel to fabricate RBC microcolumn after bacterial cellulose dissolved in NaOH-sulfourea water solution. Lectin Con A was covalently connected onto RBC matrix surface via Schiff-base formation. Lysozyme (non-glycoprotein) and transferrin (glycoprotein) were successfully separated based on their different affinities toward the immobilized Con A. Overall, the RBC microfluidic system presents great potential application in affinity chromatography of glycoproteins analysis, and this research represents a significant step to prepare bacterial cellulose (BC) as column packing material in microfluidic system. What is more, troublesome operations for lectin affinity chromatography were simplified by integrating the microfluidic chip onto a HPLC (High Performance Liquid Chromatography) system. PMID:26686130

  10. Deposition of functional cellulose films on titanium alloy surfaces

    International Nuclear Information System (INIS)

    Titanium alloy (TiAl6V4) surfaces were treated with ultraviolet (UV) radiation to remove organic 'contamination' molecules which remained on the surfaces after conventional cleaning processes. The UV-technique simultaneously revealed reactive surface hydroxyl groups at the metal surface which were monitored by the reaction with perfluorooctanoylchloride and application of Fourier-Transform infrared reflection-absorption spectroscopy and contact angle measurements, respectively. Two different cellulose polymers each made soluble in methanol by functionalized hydroxylalkyl-spacer groups and their mixtures were deposited on UV-treated TiAl6V4 surfaces. Atomic force microscopy measurements could reveal polymer films which covered the metal surfaces completely without defects. Differences were indicated in the surface structure, especially between the pure cellulose phosphate films and cinnamate containing cellulose films

  11. Enhanced electromechanical behaviors of cellulose ZnO hybrid nanocomposites

    Science.gov (United States)

    Mun, Seongchoel; Min, Seung-Ki; Kim, Hyun Chan; Im, Jongbeom; Geddis, Demetris L.; Kim, Jaehwan

    2015-04-01

    Inorganic-organic hybrid composite has attracted as its combined synergistic properties. Cellulose based inorganicorganic hybrid composite was fabricated with semiconductive nanomaterials which has functionality of nanomaterial and biocompatibility piezoelectricity, high transparency and flexibility of cellulose electro active paper namely EAPap. ZnO is providing semiconductive functionality to EAPap for hybrid nanocomposite by simple chemical reaction. Cellulose- ZnO hybrid nanocomposite (CEZOHN) demonstrates novel electrical, photoelectrical and electromechanical behaviors. This paper deals with methods to improve electromechanical property of CEZOHN. The fabrication process is introduced briefly, charging mechanism and evaluation is studied with measured piezoelectric constant. And its candidate application will be discussed such as artificial muscle, energy harvester, strain sensor, flexible electrical device.

  12. Microbial Cellulose Assembly in Microgravity

    Science.gov (United States)

    Brown, R. Malcolm, Jr.

    1998-01-01

    Based on evidence indicating a possible correlation between hypo-gravity conditions and alteration of cellulose production by the gram negative bacterium, Acetobacter xylinum, a ground-based study for a possible long term Space Shuttle flight has been conducted. The proposed experiment for A. xylinum aboard the Shuttle is the BRIC (Biological Research in a Canister), a metal container containing spaces for nine Petri plates. Using a common experimental design, the cellulose production capability as well as the survivability of the A. xylinum strains NQ5 and AY201 have been described. It should now be possible to use the BRIC for the first long term microgravity experiments involving the biosynthesis of cellulose.

  13. Characterization of Cellulose Synthesis in Plant Cells

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Maleki

    2016-01-01

    Full Text Available Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4 D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family.

  14. Characterization of Cellulose Synthesis in Plant Cells.

    Science.gov (United States)

    Maleki, Samaneh Sadat; Mohammadi, Kourosh; Ji, Kong-Shu

    2016-01-01

    Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4) D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC) from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA) proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family. PMID:27314060

  15. Extraction and characterization of cellulose microfibrils from agricultural residue –Cocos nucifera L

    International Nuclear Information System (INIS)

    The aim of this study was to extract cellulose microfibrils from the agricultural residue of coconut palm leaf sheath using chlorination and alkaline extraction process. Chemical characterization of the cellulose microfibrils confirmed that the α-cellulose mass fraction increased from 0.373 kg kg−1 to 0.896 kg kg−1 after application of several treatments including dewaxing, chlorite delignification and alkaline extraction of hemicelluloses. Similarly, the crystallinity index obtained from X-ray diffraction for leaf sheath and extracted cellulose microfibrils was found to be 42.3 and 47.7 respectively. The morphology of the cellulose microfibrils was investigated by scanning electron microscopy. The cellulose microfibrils had diameters in the range of 10–15 μm. Fourier transform infrared and Nuclear magnetic resonance spectroscopy showed that the chemical treatments removed most of the hemicellulose and lignin from the leaf sheath fibers. The thermal stability of the fibers was analyzed using thermogravimetric analysis, which demonstrated that this thermal stability was enhanced noticeably for cellulose microfibrils. This work provides a new approach for more effective utilization of coconut palm leaf sheaths to examine their potential use as pulp and paper and reinforcement fibers in biocomposite applications. -- Highlights: ► Utilization of Coconut palm leaf sheath as an alternate material for cellulose extraction. ► Using an abundant natural waste for paper pulp, biofilms and composite applications. ► Cellulose microfibrils have higher cellulose content than the leaf sheath. ► FTIR and NMR were used to study fiber structural changes during several treatments. ► Thermal stability of microfibrils is higher than their respective leaf sheath.

  16. Conception et réalisation d'une application de gestion pour avocat à partir d'OpenERP et généralisation de cette démarche à d'autres professions libérales

    OpenAIRE

    Desbaillet, Thierry; Ceillier, Thierry

    2009-01-01

    Ce rapport illustre le travail réalisé afin de créer un outil de gestion intégré pour la profession d'avocat. Notre décision a été d’utiliser un programme « open source » : « OpenERP » comme base de l’application de gestion intégrée, de l’adapter et de développer les fonctionnalités manquantes. L'application peut être testée à l'adresse suivante : http://avocat.prolibre.com avec l’utilisateur demo et le mot de passe demo. Le développement d'application de bout en bout est un concept inadapté ...

  17. Filtration properties of bacterial cellulose membranes

    OpenAIRE

    Lehtonen, Janika

    2015-01-01

    Bacterial cellulose has the same molecular formula as cellulose from plant origin, but it is characterized by several unique properties including high purity, crystallinity and mechanical strength. These properties are dependent on parameters such as the bacterial strain used, the cultivation conditions and post-growth processing. The possibility to achieve bacterial cellulose membranes with different properties by varying these parameters could make bacterial cellulose an interesting materi...

  18. Biocompatibility of Bacterial Cellulose Based Biomaterials

    OpenAIRE

    Omar P. Troncoso; Solene Commeaux; Torres, Fernando G.

    2012-01-01

    Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC) has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received...

  19. A Molecular Description of Cellulose Biosynthesis

    OpenAIRE

    McNamara, Joshua T.; Morgan, Jacob L.W.; Zimmer, Jochen

    2015-01-01

    Cellulose is the most abundant biopolymer on Earth, and certain organisms from bacteria to plants and animals synthesize cellulose as an extracellular polymer for various biological functions. Humans have used cellulose for millennia as a material and an energy source, and the advent of a lignocellulosic fuel industry will elevate it to the primary carbon source for the burgeoning renewable energy sector. Despite the biological and societal importance of cellulose, the molecular mechanism by ...

  20. The trafficking and behavior of cellulose synthase and a glimpse of potential cellulose synthesis regulators

    Institute of Scientific and Technical Information of China (English)

    Logan BASHLINE; Juan DU; Ying GU

    2011-01-01

    Cellulose biosynthesis is a topic of intensive research not only due to the significance of cellulose in the integrity of plant cell walls,but also due to the potential of using cellulose,a natural carbon source,in the production ot biofuels.Characterization of the composition,regulation,and trafficking of cellulose synthase complexes (CSCs) is critical to an understanding of cellulose biosynthesis as well as the characterization of additional proteins that contribute to the production of cellulose either through direct interactions with CSCs or through indirect mechanisms.In this review,a highlight of a few proteins that appear to affect cellulose biosynthesis,which includes:KORRIGAN (KOR),Cellulose Synthase-Interactive Protein 1 (CSI1),and the poplar microtubule-associated protein,PttMAP20,will accompany a description of cellulose synthase (CESA) behavior and a discussion of CESA trafficking compartments that might act in the regulation of cellulose biosynthesis.

  1. Iodine catalyzed acetylation of starch and cellulose

    Science.gov (United States)

    Starch and cellulose, earth's most abundant biopolymers, are of tremendous economic importance. Over 90% of cotton and 50% of wood are made of cellulose. Wood and cotton are the major resources for all cellulose products such as paper, textiles, construction materials, cardboard, as well as such c...

  2. KINETIKA FERMENTASI SELULOSA MURNI OLEH Trichoderma reesi QM 9414 MENJADI GLUKOSA DAN PENERAPANNYA PADA JERAMI PADI BEBAS LIGNIN [Kinetics of Pure Cellulose Fermentation by Trichoderma Reesei QM 9414 to Glucose and Its Application of on Lignin Free Rice Straw

    OpenAIRE

    M Iyan Sofyan

    2004-01-01

    The objectives of this research were: 1) to determine aeration rate and substrate concentration of pure cellulose to produce maximum glucose by Trichoderma reesei QM 9414 at 30 oC, and agitation 150 rpm; 2) to study the kinetics of pure cellulose fermentation by Trichoderma reesei QM 9414 to glucose and its implication upon fermentation of the lignin free rice straw. The experiment was arranged in factorial randomized complete design in three times replication. Treatments consisted of three l...

  3. Microcrystalline-cellulose and polypropylene based composite: A simple, selective and effective material for microwavable packaging.

    Science.gov (United States)

    Ummartyotin, S; Pechyen, C

    2016-05-20

    Cellulose based composite was successfully designed as active packaging with additional feature of microwavable properties. Small amount of cellulose with 10 μm in diameter was integrated into polypropylene matrix. The use of maleic anhydride was employed as coupling agent. Thermal and mechanical properties of cellulose based composite were superior depending on polypropylene matrix. Crystallization temperature and compressive strength were estimated to be 130 °C and 5.5 MPa. The crystal formation and its percentage were therefore estimated to be 50% and it can be predicted on the feasibility of microwavable packaging. Morphological properties of cellulose based composite presented the good distribution and excellent uniformity. It was remarkable to note that cellulose derived from cotton can be prepared as composite with polypropylene matrix. It can be used as packaging for microwave application. PMID:26917383

  4. MICROBIAL FERMENTATION OF ABUNDANT BIOPOLYMERS: CELLULOSE AND CHITIN

    Energy Technology Data Exchange (ETDEWEB)

    Leschine, Susan

    2009-10-31

    Our research has dealt with seven major areas of investigation: i) characterization of cellulolytic members of microbial consortia, with special attention recently given to Clostridium phytofermentans, a bacterium that decomposes cellulose and produces uncommonly large amounts of ethanol, ii) investigations of the chitinase system of Cellulomonas uda; including the purification and characterization of ChiA, the major component of this enzyme system, iii) molecular cloning, sequence and structural analysis of the gene that encodes ChiA in C. uda, iv) biofilm formation by C. uda on nutritive surfaces, v) investigations of the effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes, vi) studies of nitrogen metabolism in cellulolytic anaerobes, and vii) understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. Also, progress toward completing the research of more recent projects is briefly summarized. Major accomplishments include: 1. Characterization of Clostridium phytofermentans, a cellulose-fermenting, ethanol-producing bacterium from forest soil. The characterization of a new cellulolytic species isolated from a cellulose-decomposing microbial consortium from forest soil was completed. This bacterium is remarkable for the high concentrations of ethanol produced during cellulose fermentation, typically more than twice the concentration produced by other species of cellulolytic clostridia. 2. Examination of the use of chitin as a source of carbon and nitrogen by cellulolytic microbes. We discovered that many cellulolytic anaerobes and facultative aerobes are able to use chitin as a source of both carbon and nitrogen. This major discovery expands our understanding of the biology of cellulose-fermenting bacteria and may lead to new applications for these microbes. 3. Comparative studies of the cellulase and chitinase systems of Cellulomonas uda. Results of these studies indicate

  5. Analysis of Modified Starch Adsorption Kinetics on Cellulose Fibers via the Modified Langmuir Adsorption Theory

    OpenAIRE

    Zakrajšek, N.; Knez, S.; Ravnjak, D.; Golob, J.

    2009-01-01

    The kinetics of starch adsorption on cellulose fibers is one of the most important criteria regarding the efficient application of papermaking additives due to the continuous nature of paper production and the concomitant need to determine optimum residence times. This study presents an analysis of the kinetics of modified starch adsorption onto cellulose fibers via the application of the modified Langmuir adsorption theory (i.e. the collision theory). A model based on this theory was used to...

  6. Electrically aligned cellulose film for electro-active paper and its piezoelectricity

    International Nuclear Information System (INIS)

    Electrically aligned regenerated cellulose films were fabricated and the effect of applied electric field was investigated for the piezoelectricity of electro-active paper (EAPap). The EAPap was fabricated by coating gold electrodes on both sides of regenerated cellulose film. The cellulose film was prepared by dissolving cotton pulp in LiCl/N,N-dimethylacetamide solution followed by a cellulose chain regeneration process. During the regeneration process an external electric field was applied in the direction of mechanical stretching. Alignment of cellulose fiber chains was investigated as a function of applied electric field. The material characteristics of the cellulose films were analyzed by using an x-ray diffractometer, a field emission scanning electron microscope and a high voltage electron microscope. The application of external electric fields was found to induce formation of nanofibers in the cellulose, resulting in an increase in the crystallinity index (CI) values. It was also found that samples with higher CI values showed higher in-plane piezoelectric constant, d31, values. The piezoelectricity of the current EAPap films was measured to be equivalent or better than that of ordinary PVDF films. Therefore, an external electric field applied to a cellulose film along with a mechanical stretching during the regeneration process can enhance the piezoelectricity. (technical note)

  7. Cellulose nanocrystal from pomelo (C. Grandis osbeck) albedo: Chemical, morphology and crystallinity evaluation

    International Nuclear Information System (INIS)

    Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H2SO4, 45 °C, 45min) to produce cellulose nanocrystal. The crystalline, structural, morphological and chemical properties of both materials were studied. Result reveals the crystallinity index obtained from X-ray diffraction for cellulose nanocrystal was found higher than extracted cellulose with the value of 60.27% and 57.47%, respectively. Fourier transform infrared showed that the chemical treatments removed most of the hemicellulose and lignin from the pomelo albedo fibre. This has been confirmed further by SEM and TEM for their morphological studies. These results showed that cellulose and cellulose nanocrystal were successfully obtained from pomelo albedo and might be potentially used in producing functional fibres for food application

  8. Three-dimensional cellulose sponge: Fabrication, characterization, biomimetic mineralization, and in vitro cell infiltration.

    Science.gov (United States)

    Joshi, Mahesh Kumar; Pant, Hem Raj; Tiwari, Arjun Prasad; Maharjan, Bikendra; Liao, Nina; Kim, Han Joo; Park, Chan Hee; Kim, Cheol Sang

    2016-01-20

    In this study, cellulose based scaffolds were produced by electrospinning of cellulose acetate (CA) solution followed by its saponification with NaOH/ethanol system for 24h. The resulting nonwoven cellulose mat was treated with sodium borohydride (SB) solution. In situ hydrolysis of SB solution into the pores of the membrane produced hydrogen gas resulting a three-dimensional (3D) cellulose sponge. SEM images demonstrated an open porous and loosely packed fibrous mesh compared to the tightly packed single-layered structure of the conventional electrospun membrane. 3D cellulose sponge showed admirable ability to nucleate bioactive calcium phosphate (Ca-P) crystals in simulated body fluid (SBF) solution. SEM-EDX and X-ray diffraction studies revealed that the minerals deposited on the nanofibers have the nonstoichiometric composition similar to that of hydroxyapatite, the mineralized component of the bone. 3D cellulose sponge exhibited the better cell infiltration, spreading and proliferation compared to 2D cellulose mat. Therefore, a facile fabrication of 3D cellulose sponge with improved mineralization represents an innovative strategy for the bone tissue engineering applications. PMID:26572341

  9. Cellulose nanocrystal from pomelo (C. Grandis osbeck) albedo: Chemical, morphology and crystallinity evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Zain, Nor Fazelin Mat; Yusop, Salma Mohamad [Food Science Program, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor (Malaysia); Ahmad, Ishak [Polymer Research Centre (PORCE), School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor (Malaysia)

    2013-11-27

    Citrus peel is one of the under-utilized waste materials that have potential in producing a valuable fibre, which are cellulose and cellulose nanocrystal. Cellulose was first isolated from pomelo (C. Grandis Osbeck) albedo by combination of alkali treatment and bleaching process, followed by acid hydrolysis (65% H{sub 2}SO{sub 4}, 45 °C, 45min) to produce cellulose nanocrystal. The crystalline, structural, morphological and chemical properties of both materials were studied. Result reveals the crystallinity index obtained from X-ray diffraction for cellulose nanocrystal was found higher than extracted cellulose with the value of 60.27% and 57.47%, respectively. Fourier transform infrared showed that the chemical treatments removed most of the hemicellulose and lignin from the pomelo albedo fibre. This has been confirmed further by SEM and TEM for their morphological studies. These results showed that cellulose and cellulose nanocrystal were successfully obtained from pomelo albedo and might be potentially used in producing functional fibres for food application.

  10. In Vivo Curdlan/Cellulose Bionanocomposite Synthesis by Genetically Modified Gluconacetobacter xylinus.

    Science.gov (United States)

    Fang, Ju; Kawano, Shin; Tajima, Kenji; Kondo, Tetsuo

    2015-10-12

    Bacterial cellulose pellicle produced by Gluconacetobacter xylinus (G. xylinus) is one of the best biobased materials having a unique supernetwork structure with remarkable physiochemical properties for a wide range of medical and tissue-engineering applications. It is still necessary to modify them to obtain materials suitable for biomedical use with satisfactory mechanical strength, biodegradability, and bioactivity. The aim of this research was to develop a gene-transformation route for the production of bacterial cellulose/Curdlan (β-1,3-glucan) nanocomposites by separate but simultaneous in vivo synthesis of cellulose and Curdlan. Modification of the cellulose-nanofiber-producing system of G. xylinus enabled Curdlan to be synthesized simultaneously with cellulose nanofibers in vivo, resulting in biopreparation of nanocomposites. The obtained Curdlan/cellulose composites were characterized, and their properties were compared with those of normal bacterial cellulose pellicles, indicating that Curdlan mixed with the cellulose nanofibers at the nanoscale without disruption of the nanofiber network structure in the pellicle. PMID:26360299

  11. High performance cellulose nanocomposites: comparing the reinforcing ability of bacterial cellulose and nanofibrillated cellulose

    OpenAIRE

    Lee, K. Y.; Tammelin, T.; Schulfter, K.; Kiiskinen, H.; Samela, J.; Bismarck, A.

    2012-01-01

    This work investigates the surface and bulk properties of nanofibrillated cellulose (NFC) and bacterial cellulose (BC), as well as their reinforcing ability in polymer nanocomposites. BC possesses higher critical surface tension of 57 mN m(-1) compared to NFC (41 mN m(-1)). The thermal degradation temperature in both nitrogen and air atmosphere of BC was also found to be higher than that of NFC. These results are in good agreement with the higher crystallinity of BC as determined by XRD, meas...

  12. Application of a Detailed Emission Model for Heavy Duty Diesel Engine Simulations Application d'un modèle détaillé d'émissions pour la simulation de gros moteurs diesel

    Directory of Open Access Journals (Sweden)

    Magnusson I.

    2006-12-01

    Full Text Available A detailed chemical model describing the formation of soot and NO is applied to simulate emission formation in a heavy duty diesel engine. Cylinder flow and spray development is simulated using an engine CFD code - Speedstar. Combustion is described using a simple eddy break-up model. Modeling of the emission-chemistry/turbulent-flow interaction is based on a flamelet approach. Contrary to a typical flamelet concept, transport equations are solved for mass fractions of soot and NO. The reason being that these major emission constituencies are assumed to change slowly in comparison to typical time scales for chemical processes or transport processes important for combustion. Chemical reactions leading to production and destruction of soot and NO are, however, assumed to be fast. Soot and NO source terms are therefore evaluated from a flamelet library using a presumed probability density function and integrating over mixture fraction space. Results from simulations are compared to engine measurements inform of exhaust emission data and cylinder pressure. Un modèle avec chimie détaillée décrivant la formation des suies et du NO est appliqué à la simulation de la formation des polluants dans un gros moteur Diesel. L'écoulement et le spray sont modélisés avec le code de calcul Speedstar. La combustion est représentée par le modèle eddy break-up . La modélisation de l'interaction entre l'écoulement turbulent et la chimie des polluants est basée sur une approche de type flamelet . Cependant, à la différence d'autres travaux, des équations de transport pour les fractions massiques de suies et de NO sont résolues. Cela est justifié par la supposition que les temps caractéristiques de formation de ces composés sont longs comparés à ceux associés aux phénomènes de transport et aux réactions chimiques associées à la combustion. Cependant, les vitesses de réaction se rapportant aux suies et au NO sont supposées rapides. Cela

  13. Simultaneous microwave-assisted synthesis, characterization, thermal stability, and antimicrobial activity of cellulose/AgCl nanocomposites

    International Nuclear Information System (INIS)

    By means of a simultaneous microwave-assisted method and a simple chemical reaction, cellulose/AgCl nanocomposites have been successfully synthesized using cellulose solution and AgNO3 in N,N-dimethylacetamide (DMAc) solvent. The cellulose solution was firstly prepared by the dissolution of the microcrystalline cellulose and lithium chloride (LiCl) in DMAc. DMAc acts as both a solvent and a microwave absorber. LiCl was used as the reactant to fabricate AgCl crystals. The effects of the heating time and heating temperature on the products were studied. This method is based on the simultaneous formation of AgCl nanoparticles and precipitation of the cellulose, leading to a homogeneous distribution of AgCl nanoparticles in the cellulose matrix. The experimental results confirmed the formation of cellulose/AgCl nanocomposites with high-purity, good thermal stability and antimicrobial activity. This rapid, green and environmentally friendly microwave-assisted method opens a new window to the high value-added applications of biomass. -- Highlights: ► Cellulose/AgCl nanocomposites have been synthesized by microwave method. ► Effect of heating temperature on the nanocomposites was researched. ► Thermal stability of the nanocomposites was investigated. ► Cellulose/AgCl nanocomposites had good antimicrobial activity. ► This method is based on the simultaneous formation of AgCl and cellulose.

  14. Teores de lignina e celulose em plantas de cana-de-açúcar em função da aplicação de maturadores Lignin and cellulose contents in sugarcane after ripener application

    Directory of Open Access Journals (Sweden)

    D.K. Meschede

    2012-03-01

    Full Text Available O objetivo deste trabalho foi avaliar os teores de lignina e celulose em plantas de cana-de-açúcar após a aplicação de dois maturadores para a colheita. O experimento foi conduzido em uma área de cana-soca, cultivar SP 803280, no município de Igaraçu do Tietê/SP. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições. Os tratamentos constituíram-se da aplicação de dois maturadores: sulfometuron-methyl (Curavial e glyphosate (Roundup original. As doses utilizadas foram: glyphosate a 72 g e.a. ha-1; glyphosate a 144 g e.a. ha-1 ; glyphosate a 72 g e.a. ha-1 + sulfometuron methyl a 10 g p.c. ha-1; glyphosate a 108 g e.a. ha-1 + sulfometuron-methyl a 12 g p.c. ha-1; sulfometuron-methyl a 20 g p.c. ha-1; e a testemunha sem aplicação de maturadores. As análises de lignina e celulose foram realizadas pelo método lignina em detergente ácido modificado. O glyphosate e o sulfometuron-methyl alteraram os níveis de lignina no momento da colheita, e esse efeito foi observado também durante o crescimento da cana-de-açúcar (meses após a aplicação desses produtos. O glyphosate a 72 g e.a. ha-1 promoveu reduções nos teores de lignina, na colheita e durante o crescimento da cana-de-açúcar, quando comparados com os da testemunha, enquanto o sulfometuron-methyl isolado na menor dose (10 g ha-1 promoveu aumento nos teores desse biopolímero na soqueira da cana-de-açúcar.The aim of this study was to evaluate the content of lignin and cellulose in sugarcane after application of ripeners. The experiment was carried out in a sugarcane ratoon area, variety SP803280 in Igaraçu Tietê, São Paulo, Brazil. The experimental design was a randomized complete block with four replications. The treatments consisted of application of two ripeners: sulfometuron methyl (Curavial and glyphosate (Roundup Original. The doses used were: glyphosate 200 mL pc ha-1; glyphosate at 400 mL p.c. ha-1, glyphosate at 200 mL p

  15. Mémoire optique dans un cristal dopé erbium : efficacité, bande passante et analyse du bruit pour les applications de mémoire quantique

    OpenAIRE

    Dajczgewand, Julian

    2015-01-01

    Le traitement quantique de l’information comme moyen de surmonter les limites de l’électronique classique a connu un développement rapide dans les deux dernières décennies. Plusieurs composants pour générer, traiter et envoyer l’information quantique sont nécessaires. Dans ce contexte, les mémoires quantiques optiques apparaissent comme des composantes principales capables de communiquer l’information quantique sur de longues distances en surmontant les pertes des fibres optiques dans un sché...

  16. Une approche organisationnelle et multi-agent pour la modélisation et l'implantation de métaheuristiques, Application aux problèmes d'optimisation de réseaux de transports

    OpenAIRE

    Meignan, David

    2008-01-01

    Un objectif de cette thèse est de fournir des outils d'analyse, de conception et d'implantation des approches métaheuristiques pour l'optimisation combinatoire en les formulant dans le cadre des systèmes multi-agents. L'accent est mis sur la potentialité de mise en œuvre distribuée des approches et sur l'utilisation de techniques d'apprentissage permettant d'adapter dynamiquement des méthodes de recherche.Dans le cadre de cette thèse nous proposons tout d'abord, un framework organisationnel e...

  17. Anisotropie de la Susceptibilité Magnétique : Théorie et exemples d'application pour la mis en évidence de paléocirculations de fluides.

    OpenAIRE

    Essalhi, Mourad; Sizaret, Stanislas; Barbanson, Luc; Chen, Yan

    2008-01-01

    L'Anisotropie de la Susceptibilité Magnétique (ASM) est utilisée depuis une trentaine d'années pour déterminer la fabrique des roches (Hrouda, 1982 ; Tarling et Hrouda, 1993). Elle est aussi largement utilisée lors de travaux de géologie structurale en particulier ceux relatifs à la détermination des structures des plutons granitiques (Talbot et al., 2005). L'objectif de cette communication est de montrer, à partir de deux études de cas, comment le couplage entre l'ASM et l'analyse texturale ...

  18. Synthèse et études de l'auto-assemblage en solution de diblocs amphiphiles à base de xyloglucanes et application pour la stabilisation de protéines

    OpenAIRE

    Gauche, Cony,

    2013-01-01

    Ce travail décrit une nouvelle route synthétique qui a pour objectif l'obtention de diblocs amphiphiles constitués uniquement d'oligosaccharides issus de xyloglucanes des graines de Tamarin. Les xylogluco-oligosaccharides (XGOs, DP7, 8, 9) de tailles parfaitement définies ont été obtenus par une digestion enzymatique contrôlée (cellulase) de xyloglucanes. Dans la perspective de lier les deux blocs par cycloaddition 1,3-dipolaire de Huisgen catalysée par le Cuivre I, dite aussi chimie « click ...

  19. Synthèse de copolymères diblocs par le procédé RAFT : Application pour revêtements anti-salissures marines hybrides FRC/SPC

    OpenAIRE

    Lejars, Marlène,

    2012-01-01

    Actuellement, il existe deux types de peintures anti-salissures marines sur le marché : - Les Self-Polishing Coatings (SPC), revêtements auto-polissants à base de liants polymères hydrolysables, efficaces par relargage de biocides dans le milieu marin mais toxiques pour l’environnement ; - Les Fouling Release Coatings (FRC), revêtements hydrophobes à base de silicone, sans biocides, qui limitent la force d’adhésion des salissures mais ne sont pas efficaces en mode statique.L’objectif de cette...

  20. Production of bacterial cellulose from alternate feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    D. N. Thompson; M. A. Hamilton

    2000-05-07

    Production of bacterial cellulose by Acetobacter xylinum ATCC 10821 and 23770 in static cultures was tested from unamended food process effluents. Effluents included low- and high-solids potato effluents (LS and HS), cheese whey permeate (CW), and sugar beet raffinate (CSB). Strain 23770 produced 10% less cellulose from glucose than did 10821, and diverted more glucose to gluconate. Unamended HS, CW, and CSB were unsuitable for cellulose production by either strain, while LS was unsuitable for production by 10821. However, 23770 produced 17% more cellulose from LS than from glucose, indicating unamended LS could serve as a feedstock for bacterial cellulose.

  1. Production of Bacterial Cellulose from Alternate Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, David Neil; Hamilton, Melinda Ann

    2000-05-01

    Production of bacterial cellulose by Acetobacter xylinum ATCC 10821 and 23770 in static cultures was tested from unamended food process effluents. Effluents included low- and high-solids potato effluents (LS & HS), cheese whey permeate (CW), and sugar beet raffinate (CSB). Strain 23770 produced 10% less cellulose from glucose than did 10821, and diverted more glucose to gluconate. Unamended HS, CW, and CSB were unsuitable for cellulose production by either strain, while LS was unsuitable for production by 10821. However, 23770 produced 17% more cellulose from LS than from glucose, indicating unamended LS could serve as a feedstock for bacterial cellulose.

  2. Biochemical Disincentives to Fertilizing Cellulosic Ethanol Crops

    Science.gov (United States)

    Gallagher, M. E.; Hockaday, W. C.; Snapp, S.; McSwiney, C.; Baldock, J.

    2010-12-01

    Corn grain biofuel crops produce the highest yields when the cropping ecosystem is not nitrogen (N)-limited, achieved by application of fertilizer. There are environmental consequences for excessive fertilizer application to crops, including greenhouse gas emissions, hypoxic “dead zones,” and health problems from N runoff into groundwater. The increase in corn acreage in response to demand for alternative fuels (i.e. ethanol) could exacerbate these problems, and divert food supplies to fuel production. A potential substitute for grain ethanol that could reduce some of these impacts is cellulosic ethanol. Cellulosic ethanol feedstocks include grasses (switchgrass), hardwoods, and crop residues (e.g. corn stover, wheat straw). It has been assumed that these feedstocks will require similar N fertilization rates to grain biofuel crops to maximize yields, but carbohydrate yield versus N application has not previously been monitored. We report the biochemical stocks (carbohydrate, protein, and lignin in Mg ha-1) of a corn ecosystem grown under varying N levels. We measured biochemical yield in Mg ha-1 within the grain, leaf and stem, and reproductive parts of corn plants grown at seven N fertilization rates (0-202 kg N ha-1), to evaluate the quantity and quality of these feedstocks across a N fertilization gradient. The N fertilization rate study was performed at the Kellogg Biological Station-Long Term Ecological Research Site (KBS-LTER) in Michigan. Biochemical stocks were measured using 13C nuclear magnetic resonance spectroscopy (NMR), combined with a molecular mixing model (Baldock et al. 2004). Carbohydrate and lignin are the main biochemicals of interest in ethanol production since carbohydrate is the ethanol feedstock, and lignin hinders the carbohydrate to ethanol conversion process. We show that corn residue carbohydrate yields respond only weakly to N fertilization compared to grain. Grain carbohydrate yields plateau in response to fertilization at

  3. 硅藻土/纤维素复合助滤剂在微污染原水处理中的应用%Application of diatomite/cellulose composite filter aids on micro-polluted raw water treatment

    Institute of Scientific and Technical Information of China (English)

    盛超; 李孟; 黄凌凤; 章蕾

    2016-01-01

    以硅藻土和纤维素为原料,通过溶胶-凝胶法制备出了新型硅藻土/纤维素复合助滤剂,探究了各种制备条件对助滤剂的影响,并在高岭土悬浊液中对硅藻土、纤维素和硅藻土/纤维素的助滤性能进行了比较,同时研究了硅藻土/纤维素助滤剂对实际微污染水过滤的影响。研究结果表明:复合助滤剂的最佳制备条件为纤硅比0.67,氨水浓度5.0×10-4 mol/L,蒸馏水/纤维素40 mL/g,EtOH/硅藻土20 mL/g,60℃恒温水浴;硅藻土/纤维素复合助滤剂的助滤性能要明显优于硅藻土和纤维素助滤剂;在微污染原水直接过滤过程中,投加硅藻土/纤维素助滤剂可提高各微污染物的去除率,结合微滤膜深度处理工艺,最终出水水质满足《生活饮用水卫生标准》(GB 5749—2006)的要求。%The diatomite/cellulose filter aids were prepared using raw diatomite and cellulose via sol-gel technique. The effect of cellulose/diatomite, distilled water/cellulose, EtOH/diatomite, ammonia concentration and temperature on the properties of diatomite/cellulose filter aids were investigated.The filtration efficiency of diatomite,cellulose and diatomite/cellulose filter aids was compared.The influence of diatomite/cellulose filter aids on slightly polluted water filtration was studied.Results indicated that when 40 mL distilled water dissolved 1.0 g cellulose,20 mLEtOH carried 1.5 g diatomite,the ratio of diatomite to cellulose was 0.67,the concentration of ammonia was 5×10-4mol/L,the temperature was 60 ℃,the best diatomite/cellulose filter aids were achieved.The efficiency of diatomite/cellulose filter aids was obviously better than that by diatomite and cellulose filter aids.The pollutants removal efficiency could increase by using the diatomite/cellulose filter aids in the direct filtration process to treat the micro-polluted raw water.The results showed that the combination of

  4. In-vitro Degradation Behaviour of Irradiated Bacterial Cellulose Membrane

    Directory of Open Access Journals (Sweden)

    D. Darwis

    2012-08-01

    Full Text Available Bacterial cellulose membrane synthesized by Acetobacter xylinum in coconut water medium has potential application for Guided bone Regeneration. However, this membrane may not meet some application requirements due to its low biodegradation properties. In this paper, incorporation of gamma irradiation into the membrane is a developed strategy to increase its biodegradability properties. The in–vitro degradation study in synthetic body fluid (SBF of the irradiated membrane has been analyzed during periods of 6 months by means of weight loss, mechanical properties and scanning electron microscopy observation compared to that the un-irradiated one. The result showed that weight loss of irradiated membrane with 25 kGy and 50 kGy and immersed in SBF solution for 6 months reached 18% and 25% respectively. While un-irradiated membrane did not give significant weight loss. Tensile strength of membranes decreases with increasing of irradiation dose and further decreases in tensile strength is observed when irradiated membrane was followed by immersion in SBF solution. Microscope electron image of cellulose membranes shows that un-irradiated bacterial cellulose membrane consists of dense ultrafine fibril network structures, while irradiation result in cleavage of fibrils network of cellulose. The fibrils network become loosely after irradiated membrane immersed in SBF solution due to released of small molecular weight carbohydrates formed during by irradiation from the structure

  5. In-vitro Degradation Behaviour of Irradiated Bacterial Cellulose Membrane

    International Nuclear Information System (INIS)

    Bacterial cellulose membrane synthesized by Acetobacter xylinum in coconut water medium has potential application for Guided bone Regeneration. However, this membrane may not meet some application requirements due to its low biodegradation properties. In this paper, incorporation of gamma irradiation into the membrane is a developed strategy to increase its biodegradability properties. The in-vitro degradation study in synthetic body fluid (SBF) of the irradiated membrane has been analyzed during periods of 6 months by means of weight loss, mechanical properties and scanning electron microscopy observation compared to that the un-irradiated one. The result showed that weight loss of irradiated membrane with 25 kGy and 50 kGy and immersed in SBF solution for 6 months reached 18% and 25% respectively. While un-irradiated membrane did not give significant weight loss. Tensile strength of membranes decreases with increasing of irradiation dose and further decreases in tensile strength is observed when irradiated membrane was followed by immersion in SBF solution. Microscope electron image of cellulose membranes shows that un-irradiated bacterial cellulose membrane consists of dense ultrafine fibril network structures, while irradiation result in cleavage of fibrils network of cellulose. The fibrils network become loosely after irradiated membrane immersed in SBF solution due to released of small molecular weight carbohydrates formed during by irradiation from the structure (author)

  6. Spray-dried nanofibrillar cellulose microparticles for sustained drug release.

    Science.gov (United States)

    Kolakovic, Ruzica; Laaksonen, Timo; Peltonen, Leena; Laukkanen, Antti; Hirvonen, Jouni

    2012-07-01

    Nanofibrillar cellulose (also referred to as cellulose nanofibers, nanocellulose, microfibrillated or nanofibrillated cellulose) has gained a lot of attention in recent years in different research areas including biomedical applications. In this study we have evaluated the applicability of nanofibrillar cellulose (NFC) as a material for the formation of matrix systems for sustained drug delivery. For that purpose, drug loaded NFC microparticles were produced by a spray drying method. The microparticles were characterized in terms of size and morphology, total drug loading, and physical state of the encapsulated drug. Drug release from the microparticles was assessed by dissolution tests, and suitable mathematical models were used to explain the drug releasing kinetics. The particles had spherical shapes with diameters of around 5 μm; the encapsulated drug was mainly in amorphous form. The controlled drug release was achieved. The drug releasing curves were fitted to a mathematical model describing the drug releasing kinetics from a spherical matrix. Different drugs had different release kinetics, which was a consequence of several factors, including different solubilities of the drugs in the chosen medium and different affinities of the drugs to the NFC. It can be concluded that NFC microparticles can sustain drug release by forming a tight fiber network and thus limit drug diffusion from the system. PMID:22465549

  7. Characterisation of Flax Fibres and Flax Fibre Composites. Being cellulose based sources of materials

    DEFF Research Database (Denmark)

    Aslan, Mustafa

    growing interest among composite manufacturers for such low-cost and low-weight cellulosic fibre composites. In addition, wood and plant fibre based composites with thermoplastic polymeric matrices are recyclable, and they are cost attractive alternatives to oil based fibre reinforced polymer composites......Cellulosic fibres, like wood and plant fibres, have the potential for use as load-bearing constituents in composite materials due to their attractive properties such as high stiffness-to-weight ratio that makes cellulosic fibre composites ideal for many structural applications. There is thus a...... that currently have the largest market share for composite applications. However, the most critical limitation in the use of cellulosic fibre composites for structural applications is the lack of well described fibre properties, in particular, the tensile strength. This is due to variations in fibre...

  8. Cellulose nanomaterials in water treatment technologies.

    Science.gov (United States)

    Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R

    2015-05-01

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization. PMID:25837659

  9. Polymorphy in native cellulose: recent developments

    International Nuclear Information System (INIS)

    In a number of earlier studies, the authors developed a model of cellulose structure based on the existence of two stable, linearly ordered conformations of the cellulose chain that are dominant in celluloses I and II, respectively. The model rests on extensive Raman spectral observations together with conformational considerations and solid-state 13C-NMR studies. More recently, they have proposed, on the basis of high resolution solid-state 13C-NMR observations, that native celluloses are composites of two distinct crystalline forms that coexist in different proportions in all native celluloses. In the present work, they examine the Raman spectra of the native celluloses, and reconcile their view of conformational differences with the new level of crystalline polymorphy of native celluloses revealed in the solid-state 13C-NMR investigations

  10. 抗菌纤维素/纤维素纤维的研究进展%Research progress of antibacterial cellulose/cellulose fiber

    Institute of Scientific and Technical Information of China (English)

    徐永建; 左磊刚

    2014-01-01

    介绍了常用的无机抗菌剂和有机抗菌剂的种类及其抗菌机理,阐述了载银抗菌纤维素、纳米TiO2抗菌纤维素、季铵盐类抗菌纤维素、壳聚糖改性抗菌纤维素等抗菌纤维素及其在纺织工业、膜材料等方面的应用。指出了根据所选抗菌剂的不同,通过化学或物理方法可对纤维素和纤维素纤维进行抗菌改性。绒毛浆是一次性卫生用品吸水性垫层用绒毛化的纤维素纤维,对绒毛浆进行抗菌性改性能够提高绒毛浆的品质和功能。提出了可用于绒毛浆纤维抗菌性改性的抗菌剂和可能的方法,抗菌纤维素纤维改性在绒毛浆生产和应用中存在潜在应用前景。同时,提出了抗菌纤维素/纤维素纤维在生产和应用中存在的问题和解决办法。%The commonly used inorganic antibacterial agent and organic antibacterial agent , and their types and antibacterial mechanism were introduced .Silver antibacterial cellulose , nano TiO2 antibacterial cellulose , quaternary ammonium antibacterial cellulose , chitosan modified bacterial cellulose and other antimicrobial cellulose and its application in the textile industry ,film material and other applications were elaborated .According to the selected type of antibacterial agent ,cellulose and cellulose fibers can be modified by chemical or physical method ,fluff pulp is fluffed cellulose fibers used in disposable sanitary absorbent mat ,and fluff pulp can improve its quality and function by antibacterial modified .Paper introduced the possible antimicrobial agent and methods can be used in the antibacterial modified of fluff pulp fibers ,and the potential prospect of antibacterial modified of cellulose fibers in the pro-duction and application fluff pulp .Meanwhile the problems and solutions were presented in the production and application of antibacterial cellulose and cellulose fiber .

  11. Degradation of cellulose in the presence of ash; Nedbrytningsmoenster foer cellulosa i naervaro av aska

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, Karin; Berg, Magnus [AaF-Energi och Miljoe AB, Stockholm (Sweden); Svensson, Malin; Ecke, Holger [Luleaa Univ. of Tech. (Sweden)

    2003-04-01

    metals in combinations of ash and cellulose could also be caused by complex binding between solvent acids from the degradation of cellulose and metals in the ash. The experiments in this study have shown that the degradation product ISA results in an increased content of Pb and Zn in the leaching water from fly ash. When the experimental conditions were set to comparable conditions as for a compact and covered deposit after 250 years the leaching of Pb increased from 31 to 39 % and the leaching of Zn from 1,8 to 2,3 % when the content of ISA was increased 20 times. The disadvantages of mixing ash and cellulose are probably more important than the advantages because of the risk for increased metal mobilization. However, in some applications, for example grouting of ash to stabilize a waste deposit, the risk for metal leaching have to be compared to the advantages of using the ash. The disadvantages with ash and cellulose combinations could also be turned to advantages in special applications with processes where complex binding with ISA could give a selective washing/leaching and simultaneously the remaining metals could be fixed through carbonation.

  12. 免振自密实混凝土在后浇带施工中的应用%APPLICATION OF VIBRATION-FREE SELF-COMPACTION CONCRETE IN CONSTRUCTION OF POST-POURING BELT

    Institute of Scientific and Technical Information of China (English)

    邱金端

    2011-01-01

    后浇带施工中充分利用了自密实混凝土的高保塑性,具有在浇筑时仅靠自身重力作用而无离析、无须任何振捣即能达到自动流平、密实充填并包裹钢筋的效果,硬化后形成均匀密实的混凝土结构.结构后浇带影响工程正常施工的问题得到了解决,保证了工程的施工进度和质量.%The high slump-loss retarding property of self-compaction concrete is used effectively in the construction of post-pouring belt. During pouting, concrete can be automatically flattened, compactly filled and tightly wrapped around the steel bar under the action of its own gravity without any isolation and vibration,uniform and compacted concrete structure is formed after the concrete is hardened. The problem that structural post-pouring belt effects the normal construction is successfully solved, and engineering construction schedule and quality are guaranteed.

  13. MICROBIAL FERMENTATION OF ABUNDANT BIOPOLYMERS: CELLULOSE AND CHITIN

    Energy Technology Data Exchange (ETDEWEB)

    Leschine, Susan

    2009-10-31

    Our research has dealt with seven major areas of investigation: i) characterization of cellulolytic members of microbial consortia, with special attention recently given to Clostridium phytofermentans, a bacterium that decomposes cellulose and produces uncommonly large amounts of ethanol, ii) investigations of the chitinase system of Cellulomonas uda; including the purification and characterization of ChiA, the major component of this enzyme system, iii) molecular cloning, sequence and structural analysis of the gene that encodes ChiA in C. uda, iv) biofilm formation by C. uda on nutritive surfaces, v) investigations of the effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes, vi) studies of nitrogen metabolism in cellulolytic anaerobes, and vii) understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. Also, progress toward completing the research of more recent projects is briefly summarized. Major accomplishments include: 1. Characterization of Clostridium phytofermentans, a cellulose-fermenting, ethanol-producing bacterium from forest soil. The characterization of a new cellulolytic species isolated from a cellulose-decomposing microbial consortium from forest soil was completed. This bacterium is remarkable for the high concentrations of ethanol produced during cellulose fermentation, typically more than twice the concentration produced by other species of cellulolytic clostridia. 2. Examination of the use of chitin as a source of carbon and nitrogen by cellulolytic microbes. We discovered that many cellulolytic anaerobes and facultative aerobes are able to use chitin as a source of both carbon and nitrogen. This major discovery expands our understanding of the biology of cellulose-fermenting bacteria and may lead to new applications for these microbes. 3. Comparative studies of the cellulase and chitinase systems of Cellulomonas uda. Results of these studies indicate

  14. Bulkhead pressure measurements in model fill pours

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.J.; Roettger, J.J.

    1984-08-01

    The results of a series of model stope pours designed to investigate working pressures on bulkheads during hydraulic pouring of classified tailings backfill are reported. Total bulkhead pressures and fill water pressures were monitored under the condition of a fully saturated backfill. Similitude of the model testing is discussed and equations are developed to estimate bulkhead pressures under prototype conditions. The model results show that good base drainage, combined with a bulkhead setback, can reduce the expected bulkhead pressures to values such that timber or concrete block structures should be capable of supporting a saturated backfill.

  15. Argumenter pour ou contre son opinion

    OpenAIRE

    Beaudet, Céline; Alamargot, Denis

    2013-01-01

    Cette recherche évalue comment des étudiants en communication professionnelle peuvent composer un texte argumentatif en faisant abstraction de leurs convictions personnelles. L’analyse des arguments produits montre que l’accent est mis sur l’ethos et le pathos plutôt que sur le logos, pour influencer le lecteur par l’identification et les émotions. Des pistes didactiques pour amener les étudiants à se détacher de leurs propres opinions sont proposées en conclusion.

  16. Pouring mould during centrifugal casting process

    OpenAIRE

    J. Śleziona; R. Zagórski

    2007-01-01

    Purpose: The paper presents the model and the example simulations of the centrifugal casting of metal matrix composite reinforced with SiC, especially the distribution of the velocity of liquid composite for the initial stage of pouring the mould (up to 1s).Design/methodology/approach: Numerical simulations have been performed using the CFD program FLUENT 6.1.To simulate pouring the mould, axisymmetric swirl model has been applied. To model the air-matrix free surface (and also volume fractio...

  17. Preparation and Characterization of a Novel Spherical Cellulose Adsorbent for Reduction Adsorption of Trichloroacetic Acid

    Institute of Scientific and Technical Information of China (English)

    LIN Chun-Xiang; TIAN Chen; LIU Yi-Fan; CHENG Yang-Jian; LIN Zhang; LIU Ming-Hua

    2014-01-01

    A novel spherical cellulose adsorbent has been prepared by homogeneous graft polymerization of N,N'-methylenebisacrylamide (MBA) onto cellulose in an ionic liquid,1-N-butyl-3-methylimidazolium chloride (BMIMC1),which was then partially amine methylated through Marmich reaction to get bifunctionalized materials containing both amide and sulphinate moities.Factors affecting the attachment of functional groups were investigated.The adsorbent was characterized by Elemental Analysis (EA),Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).Cellulose adsorbent was then tested for its potential applications in the reduction adsorption of trichloroacetic acid (TCAA) from aqueous solutions.

  18. State of the Art in the Development and Properties of Protein-Based Films and Coatings and Their Applicability to Cellulose Based Products: An Extensive Review

    Directory of Open Access Journals (Sweden)

    Maria-Beatrice Coltelli

    2015-12-01

    Full Text Available There is increasing research towards the substitution of petrochemicals by sustainable components. Biopolymers such as proteins, polysaccharides, and lipids derive from a variety of crop sources and most promisingly from waste streams generated during their processing by the agro food industry. Among those, proteins of different types such as whey, casein, gelatin, wheat gluten, soy protein or zein present a potential beyond the food and feed industry for the application in packaging. The general protein hydrophilicity promotes a good compatibility to polar surfaces, such as paper, and a good barrier to apolar gases, such as oxygen and carbon dioxide. The present review deals with the development of protein-based coatings and films. It includes relevant discussion for application in paper or board products, as well as an outlook on its future industrial potential. Proteins with suitable functionalities as food packaging materials are described as well as the different technologies for processing the coatings and the current state of the art about the coating formulations for selectively modulating barrier, mechanical, surface and end of life properties. Some insights onto regulations about packaging use, end of life and perspectives of such natural coating for decreasing the environmental impact of packages are given.

  19. Approximations pour la statistique de scan discrète multi-dimensionnelle

    OpenAIRE

    Amarioarei, Alexandru

    2014-01-01

    Dans cette thèse nous obtenons des approximations et les erreurs associées pour la distribution de la statistique de scan discrète multi-dimensionnelle. La statistique de scan est vue comme le maximum d'une suite de variables aléatoires stationnaires 1-dépendante. Dans ce cadre, nous présentons un nouveau résultat pour l'approximation de la distribution de l'extremum d'une suite de variables aléatoire stationnaire 1-dépendante, avec des conditions d'application plus larges et des erreurs d'ap...

  20. Text Mining et annotation sémantique pour l’Information Scientifique

    OpenAIRE

    2013-01-01

    Un exemple d'application des technologies d'enrichissement sémantique et d'analyse de la littérature scientifique pour assister un travail de revue scientifique sur la place de la transgénèse dans la lutte contre les maladies des grandes cultures.

  1. Development of a flexible tool for the automatic comparison of bibliographic records. Application to sample collections - Développement d'un logiciel flexible pour la comparaison de notices bibliographiques et application à différentes collections

    OpenAIRE

    Borel, Alain; Krause, Jan

    2009-01-01

    Due to the multiplication of digital bibliographic catalogues (open repositories, library and bookseller catalogues), information specialists are facing the challenge of mass-processing huge amounts of metadata for various purposes. Among the many possible applications, determining the similarity between records is an important issue. Such a similarity can be interesting from a bibliographic point of view (i.e., do the records describe the same document, the answer to which can be useful for ...

  2. Surface modification of cellulose fibres

    Directory of Open Access Journals (Sweden)

    Mohamed Naceur Belgacem

    2005-06-01

    Full Text Available Several approaches to the modification of cellulose fibres are described, namely: (i physical treatments such as corona or plasma treatments under different atmospheres; (ii grafting with hydrophobic molecules using well-known sizing compounds; (iii grafting with bi-functional molecules, leaving one of the functions available for further exploitation; and (iv grafting with organometallic compounds. The modified surfaces were characterized by elemental analysis, contact angle measurements, inverse gas chromatography, X-ray photoelectron and infrared spectroscopy, wettability, etc. These different tools provided clear-cut evidence of the occurrence of chemical reactions between the grafting agent used and the hydroxy functions of the cellulose surface, as well as of the existence of covalent bonding in the ensuing composite materials between the matrix and the fibres through the use of doubly reactive coupling agents.

  3. Cellulose degradation by oxidative enzymes

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  4. Electron beam application as pre treatment of sugar cane bagasse to enzymatic hydrolysis of cellulose;Aplicacao da radiacao de feixe de eletrons com pre-tratamento do bagaco da cana-de-acucar para hidrolise enzimatica da celulose

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Vanessa Miguel

    2008-07-01

    Due to increasing worldwide shortage of food and energy sources, sugarcane bagasse has been considered as a substrate for single cell protein, animal feed, and renewable energy production. Sugarcane bagasse generally contain up to 45% glucose polymer cellulose, much of which is in a crystalline structure, 40% hemicelluloses, an amorphous polymer usually composed of xylose, arabinose, galactose, glucose, and mannose and 20% lignin, which cannot be easily separated into readily usable components due to their recalcitrant nature. Pure cellulose is readily depolymerised by radiation, but in biomass the cellulose is intimately bonded with lignin, that protect it from radiation effects. The objective of this study was the evaluation of the electron beam irradiation efficiency as a pre-treatment to enzymatic hydrolysis of cellulose in order to facilitate its fermentation and improves the production of ethanol biofuel. Samples of sugarcane bagasse were obtained in sugar/ethanol Mill sited in Piracicaba, Brazil, and were irradiated using Radiation Dynamics Electron Beam Accelerator with 1,5 MeV energy and 37 kW, in batch systems. The applied absorbed doses of the fist sampling, Bagasse A, were 20 kGy, 50 kGy, 10 0 kGy and 200 kGy. After the evaluation the preliminary obtained results, it was applied lower absorbed doses in the second assay: 5 kGy, 10 kGy, 20 kGy, 30 kGy, 50 kGy, 70 kGy, 100 kGy and 150 kGy. The electron beam processing took to changes in the sugarcane bagasse structure and composition, lignin and cellulose cleavage. The yield of enzymatic hydrolyzes of cellulose in. (author)

  5. Bacterial Cellulose (BC) as a Functional Nanocomposite Biomaterial

    Science.gov (United States)

    Nandgaonkar, Avinav Ghanashyam

    Cellulosic is the most abundant biopolymer in the landscape and can be found in many different organisms. It has been already seen use in the medical field, for example cotton for wound dressings and sutures. Although cellulose is naturally occurring and has found a number of applications inside and outside of the medical field, it is not typically produced in its pure state. A lengthy process is required to separate the lignin, hemicelluloses and other molecules from the cellulose in most renewables (wood, agricultural fibers such as cotton, monocots, grasses, etc.). Although bacterial cellulose has a similar chemical structure to plant cellulose, it is easier to process because of the absence of lignin and hemicelluloses which require a lot of energy and chemicals for removal. Bacterial cellulose (BC) is produced from various species of bacteria such as Gluconacetobacter xylinus. Due to its high water uptake, it has the tendency to form gels. It displays high tensile strength, biocompatibility, and purity compared to wood cellulose. It has found applications in fields such as paper, paper products, audio components (e.g., speaker diaphragms), flexible electronics, supercapacitors, electronics, and soft tissue engineering. In my dissertation, we have functionalized and studied BC-based materials for three specific applications: cartilage tissue engineering, bioelectronics, and dye degradation. In our first study, we prepared a highly organized porous material based on BC by unidirectional freezing followed by a freeze-drying process. Chitosan was added to impart additional properties to the resulting BC-based scaffolds that were evaluated in terms of their morphological, chemical, and physical properties for cartilage tissue engineering. The properties of the resulting scaffold were tailored by adjusting the concentration of chitosan over 1, 1.5, and 2 % (by wt-%). The scaffolds containing chitosan showed excellent shape recovery and structural stability after

  6. Cell adhesion on cellulose nanofibrils

    OpenAIRE

    Liljeström, Anna

    2016-01-01

    Cellulose nanofibrils (CNF) is an emerging biomaterial suitable for medical research. CNF hydrogel has been used as a three dimensional platforms for cell culture. This thesis aims to understand how human liver carcinoma (HepG2) cells interact with CNF. Measurements were performed with Quartz crystal microbalance with dissipation in order to quantify cell adsorption on CNF. Furthermore, the effect of the cell medium on the viscoelastic properties of CNF and on cell-CNF interactions were ...

  7. Lowering costs of microbial cellulose

    OpenAIRE

    Pajuelo, María González; Bungay, Henry; Hogg, Tim; Vasconcelos, Isabel

    1997-01-01

    We have been conducting research with Acetobacter xylinium for microbial conversion of sugars to cellulose. A rotating disk biological contactor should lower costs considerably because its production rates are greater than for the usual method of surface culture. Another major cost saving comes from replacing expensive sugars in the medium with sugars derived from wastes. Extracts of spent grapes from wastes of Portuguese wine factories supply suitable sugars for good production of micr...

  8. Effect of Pour Size on Concrete Placing Productivity in Nigeria

    Directory of Open Access Journals (Sweden)

    Olaoluwa Olatunde

    2012-06-01

    Full Text Available Pour size as one of the site factors affecting concreting was examined to determine its effects on concreting productivity. A total of 167 separate concrete pours were observed on 25 building construction sites in Lagos, Nigeria,comprising 35 pours placed by crane and skip; 26 pours placed by dumper; 58 pours placed by wheelbarrow; 37 pours placed by head pan; and 11 pours placed jointly by pump, wheelbarrow and head pan. Data collected from the daily concrete pours were analyzed to determine operational productivity rates. The relationship between concreting productivity and pour size was examined using regression analyses to develop a model relating productivity to pour size. The results showed that irrespective of placing method, productivity generally increased by 1.1 m3/h for every 10 m3 increase in pour size. It was recommended that the obtained index of productivity increase per pour size be standardised for use in improving on-site productivity in the Nigerian construction industry.

  9. Preparation of reactive fibre interfaces using multifunctional cellulose derivatives.

    Science.gov (United States)

    Vega, Beatriz; Wondraczek, Holger; Bretschneider, Leonore; Näreoja, Tuomas; Fardim, Pedro; Heinze, Thomas

    2015-11-01

    Cellulose fibres have poor reactivity and limited potential for surface engineering with advanced chemical functionalization in water. In this work, cellulose fibres were decorated with azide functions by charge-directed self-assembly of a novel water-soluble multifunctional cellulose derivative yielding reactive fibres. Propargylamine and 1-ethynylpyrene were utilized as a proof of concept that alkyne molecules may react with the azide functions of the reactive fibres via copper(I)-catalyzed azide-alkyne Huisgen cycloaddition (CuAAc) reaction in mild conditions. Chemical characterization of the fibres was carried out using classical techniques such as Raman-, fluorescence-, and UV-vis spectroscopy. Among other techniques, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray spectroscopy (XPS), two-photon microscopy (TPM), and inductively coupled plasma mass spectrometry (ICP-MS) were useful tools for additional characterization of the fibres decorated with amino- or photoactive groups. The information gathered in this work might contribute to the basis for the preparation of reactive cellulose-based interfaces with potential application in CuAAc reactions. PMID:26256349

  10. Nano zinc oxide-sodium alginate antibacterial cellulose fibres.

    Science.gov (United States)

    Varaprasad, Kokkarachedu; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Seo, Jongchul

    2016-01-01

    In the present study, antibacterial cellulose fibres were successfully fabricated by a simple and cost-effective procedure by utilizing nano zinc oxide. The possible nano zinc oxide was successfully synthesized by precipitation technique and then impregnated effectively over cellulose fibres through sodium alginate matrix. XRD analysis revealed the 'rod-like' shape alignment of zinc oxide with an interplanar d-spacing of 0.246nm corresponding to the (101) planes of the hexagonal wurtzite structure. TEM analysis confirmed the nano dimension of the synthesized zinc oxide nanoparticles. The presence of nano zinc oxide over cellulose fibres was evident from the SEM-EDS experiments. FTIR and TGA studies exhibited their effective bonding interaction. The tensile stress-strain curves data indicated the feasibility of the fabricated fibres for longer duration utility without any significant damage or breakage. The antibacterial studies against Escherichia coli revealed the excellent bacterial devastation property. Further, it was observed that when all the parameters remained constant, the variation of sodium alginate concentration showed impact in devastating the E. coli. In overall, the fabricated nano zinc oxide-sodium alginate cellulose fibres can be effectively utilized as antibacterial fibres for biomedical applications. PMID:26453887

  11. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis

    Science.gov (United States)

    Habibi, Neda

    2015-02-01

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33 nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the Nsbnd CH3 functional group about 2850 cm-1 is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

  12. The Cellulase KORRIGAN Is Part of the Cellulose Synthase Complex

    NARCIS (Netherlands)

    Vain, T.; Crowell, E.F.; Timpano, H.; Biot, E.; Desprez, T.; Mansoori Zangir, N.; Trindade, L.M.; Pagant, S.; Robert, S.; Hofte, H.; Gonneau, M.; Vernhettes, S.

    2014-01-01

    Plant growth and organ formation depend on the oriented deposition of load-bearing cellulose microfibrils in the cell wall. Cellulose is synthesized by a large relative molecular weight cellulose synthase complex (CSC), which comprises at least three distinct cellulose synthases. Cellulose synthesis

  13. Optimisation et contrôle optimale de modes culturaux : application du modèle GreenLab pour l’aide à la décision en agriculture.

    OpenAIRE

    Qi, Rui

    2010-01-01

    L'objectif de cette thèse est de développer des méthodes d'optimisation et de contrôle optimal pour l'amélioration du rendement des cultures en utilisant le modèle de croissance de plantes GreenLab. Les méthodes proposées doivent se placer dans le contexte suivant: (1) la recherche d'amélioration du rendement se fait par des simulations basées sur le modèle structure-fonction GreenLab et (2) les méthodes utilisées sont des algorithmes d'optimisation heuristiques et des techniques de contrôle ...

  14. Démarche d'Ingénierie Système pour les systèmes de management.Application à l'ingénierie d'un processus de conception et développement

    OpenAIRE

    Bron, Jean-Yves; Salzemann, Bruno

    2015-01-01

    Le pôle AIP-PRIMECA Lorraine est un centre de ressources de l'Université de Lorraine, il met à disposition des filières de formation des plateformes à caractères industriels. Dans cette publication, nous proposons une démarche d'ingénierie d'un processus de son système de management. L'originalité de notre contribution repose principalement sur l'usage de méthodologies issues de l'Ingénierie des Systèmes Complexes pour la conception d'un processus d'un système de management. Ce dernier étant ...

  15. EQUATION D'ETAT AB INITIO DE L'HYDROGENE DANS LA MATIERE DENSE ET TIEDE ET APPLICATION A L'IMPLOSION DE CIBLES POUR LA FUSION PAR CONFINEMENT INERTIEL

    OpenAIRE

    Caillabet, Laurent

    2011-01-01

    Dans le domaine de la fusion par confinement inertiel (FCI), l'équation d'état (EoS) de l'hydrogène et de ses isotopes est très certainement une des propriétés les plus importantes à connaître. Les EoS basées sur des modèles chimiques peinent à donner une description univoque de l'hydrogène dans le domaine de couplage et de dégénérescence partiels, appelé matière dense et tiède, ou Warm Dense Matter (WDM). En effets, ces modèles utilisent des potentiels ad hoc pour décrire les interactions à ...

  16. Architectures de convertisseurs statiques et contrôle-commande associé pour les systèmes pile à combustible et mécatroniques de puissance : Application aux véhicules électriques

    OpenAIRE

    De Bernardinis, Alexandre

    2015-01-01

    Les travaux présentés en vue d'obtenir le diplôme d'Habilitation à diriger les recherches (HDR) font la synthèse de plus de dix ans de mes recherches au sein de l'INRETS devenu ensuite IFSTTAR (Institut français des sciences et technologies du transport, de l'aménagement et des réseaux) à partir de 2011, travaux que j'ai accomplis en tant que chercheur dans cet institut public. Mes recherches portent sur l'analyse d'architectures de convertisseurs statiques pour les systèmes mécatroniques de ...

  17. Caractérisation en commutation douce d'IGBT 6,5 kV pour l'application transformateur moyenne fréquence en traction ferroviaire

    OpenAIRE

    Martin, Jérémy

    2010-01-01

    Ce travail concerne l’étude et la réalisation d’une architecture multicellulaire de conversion d’énergie électrique haute tension avec étage intermédiaire alternatif moyenne fréquence destinée à la traction électrique ferroviaire. L’objectif de ce travail est de diminuer la masse et le volume de l’étage de conversion alternatif-continu que l’on retrouve dans les engins de traction conçus pour circuler sur les réseaux alternatifs 25kV-50Hz ou 15kV-16Hz2/3. La recherche de gains sur l’étage de ...

  18. Développement d’une vanne d’injection d’échantillons liquides pour la micro-chromatographie en phase gazeuse : applications à des problématiques industrielles

    OpenAIRE

    Malicet, Vincent Ylane

    2015-01-01

    L'amélioration du contrôle des procédés est un besoin industriel permanent. Depuis les années deux-milles se développe un nouveau concept d'analyse industrielle en ligne consistant à mettre en oeuvre des micro-systèmes standardisés modulaires implantés au plus près des procédés. La micro-chromatographie en phase gazeuse occupe une place de choix parmi l'ensemble des systèmes analytiques qualitatifs et quantitatifs utilisés pour le contrôle des procédés. Jusqu'à ce jour, cette technologie n'es...

  19. Cellulose-binding domains: tools for innovation in cellulosic fibre production and modification

    NARCIS (Netherlands)

    Quentin, M.G.E.; Valk, van der H.C.P.M.; Dam, van J.E.G.; Jong, de E.

    2003-01-01

    Plant cell walls are composed of cellulose, nature's most abundant macromolecule, and therefore represent a renewable resource of special technical importance. Cellulose degrading enzymes involved in plant cell wall loosening (expansins), or produced by plant pathogenic microorganisms (cellulases),

  20. Engineering of a novel cellulose-adherent cellulolytic Saccharomyces cerevisiae for cellulosic biofuel production.

    Science.gov (United States)

    Liu, Zhuo; Ho, Shih-Hsin; Sasaki, Kengo; den Haan, Riaan; Inokuma, Kentaro; Ogino, Chiaki; van Zyl, Willem H; Hasunuma, Tomohisa; Kondo, Akihiko

    2016-01-01

    Cellulosic biofuel is the subject of increasing attention. The main obstacle toward its economic feasibility is the recalcitrance of lignocellulose requiring large amount of enzyme to break. Several engineered yeast strains have been developed with cellulolytic activities to reduce the need for enzyme addition, but exhibiting limited effect. Here, we report the successful engineering of a cellulose-adherent Saccharomyces cerevisiae displaying four different synergistic cellulases on the cell surface. The cellulase-displaying yeast strain exhibited clear cell-to-cellulose adhesion and a "tearing" cellulose degradation pattern; the adhesion ability correlated with enhanced surface area and roughness of the target cellulose fibers, resulting in higher hydrolysis efficiency. The engineered yeast directly produced ethanol from rice straw despite a more than 40% decrease in the required enzyme dosage for high-density fermentation. Thus, improved cell-to-cellulose interactions provided a novel strategy for increasing cellulose hydrolysis, suggesting a mechanism for promoting the feasibility of cellulosic biofuel production. PMID:27079382

  1. Effects of reaction conditions on cellulose structures synthesized in vitro by bacterial cellulose synthases.

    Science.gov (United States)

    Penttilä, Paavo A; Sugiyama, Junji; Imai, Tomoya

    2016-01-20

    Cellulose was synthesized by cellulose synthases extracted from the Komagataeibacter xylinus (formerly known as Gluconacetobacter xylinus). The effects of temperature and centrifugation of the reaction solution on the synthesis products were investigated. Cellulose with number-average degree of polymerization (DPn) roughly in the range 60-80 and cellulose II crystal structure was produced under all conditions. The amount of cellulose varied with temperature and centrifugation, and the centrifugation at 2000 × g also slightly reduced the DPn. Cellulose production was maximal around the temperature 35 °C and without centrifugation. At higher temperatures and during centrifugation at 2000 × g the proteins started to denature, causing differences also in the morphology of the cellulosic aggregates, as seen with electron microscopy. These observations serve as a basis for discussions about the factors affecting the structure formation and chain length of in vitro synthesized cellulose. PMID:26572398

  2. Micromechanics and poroelasticity of hydrated cellulose networks.

    Science.gov (United States)

    Lopez-Sanchez, P; Rincon, Mauricio; Wang, D; Brulhart, S; Stokes, J R; Gidley, M J

    2014-06-01

    The micromechanics of cellulose hydrogels have been investigated using a new rheological experimental approach, combined with simulation using a poroelastic constitutive model. A series of mechanical compression steps at different strain rates were performed as a function of cellulose hydrogel thickness, combined with small amplitude oscillatory shear after each step to monitor the viscoelasticity of the sample. During compression, bacterial cellulose hydrogels behaved as anisotropic materials with near zero Poisson's ratio. The micromechanics of the hydrogels altered with each compression as water was squeezed out of the structure, and microstructural changes were strain rate-dependent, with increased densification of the cellulose network and increased cellulose fiber aggregation observed for slower compressive strain rates. A transversely isotropic poroelastic model was used to explain the observed micromechanical behavior, showing that the mechanical properties of cellulose networks in aqueous environments are mainly controlled by the rate of water movement within the structure. PMID:24784575

  3. CELLULOSE POWDER FROM OLIVE INDUSTRY SOLID WASTE

    Directory of Open Access Journals (Sweden)

    Othman A. Hamed,

    2012-07-01

    Full Text Available In the present work, a method for extracting cellulose from olive industry solid waste has been developed. The method involves subjecting solid olive waste to kraft pulping, followed by multistep bleaching processes. The totally free chlorine chemical bleaching sequence APEP was the most effective and gave an average cellulose yield of about 35%. The extracted cellulose was extensively characterized using FTIR, EMS, HPLC, and viscometry. Our key finding in this study is that the extracted cellulose was found to have physio-chemical properties that are similar to those of conventional microcrystalline cellulose (MCC. This is important, as our results show how lignocellulosic agricultural wastes can be utilized to produce high value cellulose powder.

  4. Optimized Monitoring of Production of Cellulose Nanowhiskers from Opuntia ficus-indica (Nopal Cactus)

    OpenAIRE

    Horacio Vieyra; Ulises Figueroa-López; Andrea Guevara-Morales; Berenice Vergara-Porras; Eduardo San Martín-Martínez; Miguel Ángel Aguilar-Mendez

    2015-01-01

    Preparation of cellulose nanowhiskers (CNWs) has grown significantly because they are useful for a wide range of applications. Additional advantage in their design requires that they meet the following characteristics: nontoxicity, abundance, sustainability, renewability, and low cost. To address these requirements, nanowhiskers were prepared from Opuntia ficus-indica (nopal) cellulose by acid hydrolysis. Monitoring the process of CNWs preparation is necessary to ensure maximum yield and puri...

  5. Characterization of a novel swollenin from Penicillium oxalicum in facilitating enzymatic saccharification of cellulose

    OpenAIRE

    Kang, Kang; Wang, Shaowen; Lai, Guohong; Liu, Gang; XING, MIAO

    2013-01-01

    Background Plant expansins and fungal swollenin that can disrupt crystalline cellulose have great potential for applications in conversion of biomass. Recent studies have been mainly focused on Trichoderma reesei swollenin that show relatively low activity in the promotion of cellulosic hydrolysis. Our aim was to isolate a novel swollenin with greater disruptive activity, to establish an efficient way of producing recombinant swollenin, and to optimize the procedure using swollenin in facilit...

  6. Physical, Antioxidant and Antimicrobial Characteristics of Carboxymethyl Cellulose Edible Film Cooperated with Clove Essential Oil

    OpenAIRE

    Ramin Khaksar; Alireza Dashipour; Hedayat Hosseini; Saeedeh Shojaee-Aliabadi; Kiandokht Ghanati

    2014-01-01

    Background: Carboxymethyl cellulose (CMC) is one of the most common cellulose derivatives. It has many applications such as edible films and coating. Antioxidant and antimicrobial of essential oils and their direct or indirect usage in foods have been investigated. This study focuses on the physical, chemical, antioxidant and antimicrobial characteristics of CMC edible film incorporated with clove essential oils (CEO). Materials and Methods: In this experimental study, CMC edible films wit...

  7. Potential of Biosynthesized Silver Nanoparticles as Nanocatalyst for Enhanced Degradation of Cellulose by Cellulase

    OpenAIRE

    Salunke, Bipinchandra K.; Sawant, Shailesh S.; Tae Koo Kang; Deok Yun Seo; Youngjong Cha; Sun A. Moon; Bassam Alkotaini; Ezhaveni Sathiyamoorthi; Beom Soo Kim

    2015-01-01

    Silver nanoparticles (AgNPs) as a result of their excellent optical and electronic properties are promising catalytic materials for various applications. In this study, we demonstrate a novel approach for enhanced degradation of cellulose using biosynthesized AgNPs in an enzyme catalyzed reaction of cellulose hydrolysis by cellulase. AgNPs were synthesized through reduction of silver nitrate by extracts of five medicinal plants (Mentha arvensis var. piperascens, Buddleja officinalis Maximowic...

  8. Treatment of tympanic membrane perforation using bacterial cellulose: a randomized controlled trial

    OpenAIRE

    Fábio Coelho Alves Silveira; Flávia Cristina Morone Pinto; Sílvio da Silva Caldas Neto; Mariana de Carvalho Leal; Jéssica Cesário; José Lamartine de Andrade Aguiar

    2016-01-01

    ABSTRACT INTRODUCTION: Promising treatments for tympanic membrane perforation closure have been studied. Therapies derived from tissue engineering probably eliminate the need for conventional surgery. Bacterial cellulose is presented as an alternative that is safe, biocompatible, and has low toxicity. OBJECTIVES: To investigate the effect on healing of direct application of a bacterial cellulose graft on the tympanic membrane compared to the conventional approach with autologous fascia. ME...

  9. Pectin/carboxymethyl cellulose/microfibrillated cellulose composite scaffolds for tissue engineering.

    Science.gov (United States)

    Ninan, Neethu; Muthiah, Muthunarayanan; Park, In-Kyu; Elain, Anne; Thomas, Sabu; Grohens, Yves

    2013-10-15

    Highly porous three-dimensional scaffolds made of biopolymers are of great interest in tissue engineering applications. A novel scaffold composed of pectin, carboxymethyl cellulose (CMC) and microfibrillated cellulose (MFC) were synthesised using lyophilisation technique. The optimised scaffold with 0.1% MFC, C(0.1%), showed highest compression modulus (~3.987 MPa) and glass transition temperature (~103 °C). The pore size for the control scaffold, C(0%), was in the range of 30-300 μm while it was significantly reduced to 10-250 μm in case of C(0.1%). Using micro computed tomography, the porosity of C(0.1%) was estimated to be 88%. C(0.1%) showed excellent thermal stability and lower degradation rate compared to C(0%). The prepared samples were also characterised using XRD and FTIR. C(0.1%) showed controlled water uptake ability and in vitro degradation in PBS. It exhibited highest cell viability on NIH3T3 fibroblast cell line. These results suggest that these biocompatible composite scaffolds can be used for tissue engineering applications. PMID:23987424

  10. Water-soluble cellulose acetate from waste cotton fabrics and the aqueous processing of all-cellulose composites.

    Science.gov (United States)

    Cao, Jie; Sun, Xunwen; Lu, Canhui; Zhou, Zehang; Zhang, Xinxing; Yuan, Guiping

    2016-09-20

    The objective of this study is to explore the possibility of using waste cotton fabrics (WCFs) as low cost feedstock for the production of value-added products. Our previous study (Tian et al., 2014) demonstrated that acidic ionic liquids (ILs) can be highly efficient catalysts for controllable synthesis of cellulose acetate (CA) due to their dual function of swelling and catalyzing. In this study, an optimized "quasi-homogeneous" process which required a small amount of acidic ILs as catalyst was developed to synthesize water-soluble CA from WCFs. The process was optimized by varying the amounts of ILs and the reaction time. The highest conversion of water-soluble CA from WCFs reached 90.8%. The structure of the obtained water-soluble CA was characterized and compared with the original WCFs. Moreover, we demonstrate for the first time that fully bio-based and transparent all-cellulose composites can be fabricated by simple aqueous blending of the obtained water-soluble CA and two kinds of nanocelluloses (cellulose nanocrystals and cellulose nanofibrils), which is attractive for the applications in disposable packaging materials, sheet coating and binders, etc. PMID:27261730

  11. Size Effects of Nano-crystalline Cellulose

    Institute of Scientific and Technical Information of China (English)

    Guo Kang LI; Xiao Fang LI; Yong JIANG; Mei Zhen ZENG; En Yong DING

    2003-01-01

    Natural cellulose with the crystal form of cellulose Ⅰ, when treated with condensed lye(e.g. 18%NaOH), can change into new crystal form of cellulose Ⅱ. But the nano-crystallinecellulose(NCC) can do it when only treated with dilute lye (e.g. 1%NaOH) at room temperatureand even can dissolve into slightly concentrated lye (e.g. 4%NaOH).

  12. Bulk and interfacial properties of cellulose ethers

    OpenAIRE

    Bodvik, Rasmus

    2012-01-01

    This work summarizes several studies that all concern cellulose ethers of the types methylcellulose (MC) hydroxypropylmethylcellulose (HPMC) and ethyl(hydroxyethyl)cellulose (EHEC). They share the feature of negative temperature response, as they are soluble in water at room temperature but phase separate and sometimes form gels at high temperatures. The different types of viscosity transitions occurring in these three cellulose ethers are well-known. However, earlier studies have not solved ...

  13. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Ogata, Satoshi; Numakawa, Tetsuya; Kubo, Takuya

    2010-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  14. Drag Reduction of Bacterial Cellulose Suspensions

    OpenAIRE

    Satoshi Ogata; Tetsuya Numakawa; Takuya Kubo

    2011-01-01

    Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechani...

  15. Cellulose biosynthesis and function in bacteria.

    OpenAIRE

    Ross, P; Mayer, R; Benziman, M

    1991-01-01

    The current model of cellulose biogenesis in plants, as well as bacteria, holds that the membranous cellulose synthase complex polymerizes glucose moieties from UDP-Glc into beta-1,4-glucan chains which give rise to rigid crystalline fibrils upon extrusion at the outer surface of the cell. The distinct arrangement and degree of association of the polymerizing enzyme units presumably govern extracellular chain assembly in addition to the pattern and width of cellulose fibril deposition. Most e...

  16. Liquid crystalline cellulose derivatives for mirrorless lasing

    OpenAIRE

    Wenzlik, Daniel

    2013-01-01

    In this thesis cholesteric films made of liquid crystalline cellulose derivatives with improved optical properties were prepared. The choice of the solvent, hydrogen bond influencing additives, the synthetic realization of a very high degree of substitution on the cellulosic polymer and the use of mechanical stirring at the upper concentration limit of the liquid crystalline range were the basis for an improved alignment of the applied cellulose tricarbamates. In combination with a tuned subs...

  17. Lyocell, The New Generation of Regenerated Cellulose

    OpenAIRE

    Éva Borbély

    2008-01-01

    For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon) or complex (e.g.cuprammonium rayon). For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocel...

  18. Alexa Fluor-labeled Fluorescent Cellulose Nanocrystals for Bioimaging Solid Cellulose in Spatially Structured Microenvironments

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Mo, Kai-For; Shin, Yongsoon; Vasdekis, Andreas; Warner, Marvin G.; Kelly, Ryan T.; Orr, Galya; Hu, Dehong; Dehoff, Karl J.; Brockman, Fred J.; Wilkins, Michael J.

    2015-03-18

    Cellulose nanocrystal materials have been labeled with modern Alexa Fluor dyes in a process that first links the dye to a cyanuric chloride molecule. Subsequent reaction with cellulose nanocrystals provides dyed solid microcrystalline cellulose material that can be used for bioimaging and suitable for deposition in films and spatially structured microenvironments. It is demonstrated with single molecular fluorescence microscopy that these films are subject to hydrolysis by cellulose enzymes.

  19. Alteration of in vivo cellulose ribbon assembly by carboxymethylcellulose and other cellulose derivatives

    OpenAIRE

    1982-01-01

    In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presen...

  20. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 Å Resolution.

    Science.gov (United States)

    Du, Juan; Vepachedu, Venkata; Cho, Sung Hyun; Kumar, Manish; Nixon, B Tracy

    2016-01-01

    Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA) exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and support the

  1. Structure of the Cellulose Synthase Complex of Gluconacetobacter hansenii at 23.4 A Resolution.

    Directory of Open Access Journals (Sweden)

    Juan Du

    Full Text Available Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts of crystalline cellulose. Its cellulose synthase (AcsA exists as a complex with accessory protein AcsB, forming a 'terminal complex' (TC that has been visualized by freeze-fracture TEM at the base of ribbons of crystalline cellulose. The catalytic AcsAB complex is embedded in the cytoplasmic membrane. The C-terminal portion of AcsC is predicted to form a translocation channel in the outer membrane, with the rest of AcsC possibly interacting with AcsD in the periplasm. It is thus believed that synthesis from an organized array of TCs coordinated with extrusion by AcsC and AcsD enable this bacterium to make crystalline cellulose. The only structural data that exist for this system are the above mentioned freeze-fracture TEM images, fluorescence microscopy images revealing that TCs align in a row, a crystal structure of AcsD bound to cellopentaose, and a crystal structure of PilZ domain of AcsA. Here we advance our understanding of the structural basis for crystalline cellulose production by bacterial cellulose synthase by determining a negative stain structure resolved to 23.4 Å for highly purified AcsAB complex that catalyzed incorporation of UDP-glucose into β-1,4-glucan chains, and responded to the presence of allosteric activator cyclic diguanylate. Although the AcsAB complex was functional in vitro, the synthesized cellulose was not visible in TEM. The negative stain structure revealed that AcsAB is very similar to that of the BcsAB synthase of Rhodobacter sphaeroides, a non-crystalline cellulose producing bacterium. The results indicate that the crystalline cellulose producing and non-crystalline cellulose producing bacteria share conserved catalytic and membrane translocation components, and

  2. Characterisation of hierarchically-structured cellulose hydrogels by small angle neutron scattering

    International Nuclear Information System (INIS)

    This work reports on the characterisation of cellulose hydrogels by means of small angle neutron scattering (SANS), combined with complementary techniques such as small angle X-ray scattering, X-ray diffraction, NMR spectroscopy and electron microscopy. Pure cellulose hydrogels were synthesized by cultivation of Gluconacetobacter xylinus strains in glucosecontaining media. Composites were also produced by incorporating polysaccharides typically found in plant cell walls (PCW) into the culture media. The application of a multi-technique characterisation approach enabled elucidation of the complex hierarchical architecture of cellulose hydrogels. Cellulose ribbons, typically modelled as solid one-phase structures, were proven to consist of a sub-structure of cellulose microfibrils interacting with each other and with solvent by means of a dense hydrogen bonding network. The existence of such sub-structure led to the creation of regions with different solvent accessibility within the ribbons, as indicated by the SANS data of pure and composite cellulose hydrogels. Based on this, a core-shell cylinder model combined with an interfacial scattering term was applied to fit the SANS contrast variation data. The fitting results suggested a different effect on the ribbons’ solvent exchange for the diverse composite hydrogels and, supported by additional characterisation, highlighted the distinct interaction mechanisms between cellulose and PCW polysaccharides. Furthermore, the production of partially deuterated cellulose hydrogels by using a deuterated glucose-based feedstock was seen to effectively enhance the neutron scattering length density contrast, opening new possibilities to selectively match the different components in composite hydrogels. The structure of the deuterated cellulose was compared with the native protiated cellulose and SANS contrast variation experiments confirmed the presence of solvent trapped within the cellulose ribbons, behaving differently to

  3. Increasing cellulose production and transgenic plant growth in forest tree species

    Institute of Scientific and Technical Information of China (English)

    TANG Wei; Aaron Nelson; Emmanuel Johnson

    2005-01-01

    effect of the antisense transgene expression on lignin content, cellulose accumulation, and loblolly pine biomass; and (4) select fast growth and high cellulose accumulation transgenic loblolly pine lines for future commercial application.

  4. Controlling the structure and rheology of TEMPO-oxidized cellulose in zinc chloride aqueous suspensions for fabricating advanced nanopaper

    Science.gov (United States)

    Wang, Sha; Zhang, Xin; Hu, Liangbing; Briber, Robert; Wang, Howard; Zhong, Linxin

    Due to its abundance, low-cost, biocompatibility and renewability, cellulose has become an attractive candidate as a functional material for various advanced applications. A key to novel applications is the control of the structure and rheology of suspensions of fibrous cellulose. Among many different approaches of preparing cellulose suspensions, zinc chloride addition to aqueous suspensions is regarded an effective practice. In this study, effects of ZnCl2 concentration on TEMPO-oxidized cellulose (TOC) nanofiber suspensions have been investigated. Highly-transparent cellulose nanofiber suspension can be rapidly obtained by dissolving TOC in 65 wt.% zinc chloride aqueous solutions at room temperature, whereas a transparent zinc ion cross-linked TOC gel could be obtained with zinc chloride concentration as low as 10 wt. %. The structural and rheological characteristics of TOC/ZnCl2 suspensions have been measured to correlate to the performance of thetransparent and flexible nanocellulose paper subsequently produced via vacuum filtration or wet-casting processes.

  5. 新型组织工程材料细菌纤维素在眼科等医学领域的研究与应用%The research progress in bacterial cellulose and its application as new tissue engineering material in ophthalmic and other medical fields

    Institute of Scientific and Technical Information of China (English)

    李京

    2013-01-01

    Bacterial cellulose iunique and promising material aimplantand scaffoldin tissue engineering study.Iicomposed of pure cellulose nanofibemesh spun by bacteria.Aithigh watecontenand purity,iimore biocompatible fomultiple medical applications.In addition,iieasy to control itmechanical strength,chemical structure and morphology,therefore iimore suitable to be used abiomedical material in vivo.Bacterial cellulose habeen applied atissue engineering material in clinical medical aspects,foexample,wound dressingalternatives,artificial skin,artery eluting stent,bone tissue engineering scaffold,artificial blood vessel,artificial hearvalve prosthesis.The application of bacterial cellulose ialso extended to the construction of tissue engineering corneal stromand corneal contaclens.Thipapereviewthe progresin the applying spectrum of bacterial cellulose in corneal tissue engineering and othemedical field.%细菌纤维素(BC)是一种独特的具有应用前景的组织工程支架材料,由细菌产生的纳米纯纤维网状结构组成.BC具有强度大及含水量高的优点,具有更好的生物相容性,BC的机械强度、化学特性和形态学具有可控性,更适用于作为体内的生物材料.BC已广泛应用于生物医学领域,包括作为局部携带药物的伤口敷料替代品,在神经外科用于人工皮肤的覆盖和硬脑膜修补术以及动脉涂层支架,在骨科用于骨组织工程支架,在显微外科作为人工血管构建,在心血管外科用于人工心脏瓣膜的构建等,此外,BC的用途也已扩展到眼科领域组织工程化角膜基质的构建和角膜接触镜的生产.就BC在组织工程角膜及其他医学领域的应用进行综述.

  6. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. PMID:27127053

  7. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.

  8. Chemo-catalytic valorization of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Palkovits, R. [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie

    2012-07-01

    Cellulose can be utilized as carbon source for the production of novel platform molecules as well as fuel motifs. Promising transformation strategies cover the hydrolytic hydrogenation or hydrogenolysis of cellulose to sugar alcohols, the hydrolysis of cellulose to glucose followed by dehydration to 5-hydroxymethylfurfural or levulinic acid and the further hydrogenation of levulinic acid to {gamma}-valerolactone. Main challenges result from the high degree of functionalization of cellulosic feedstocks. In line, processes are carried out in liquid phase utilizing rather polar solvents and aiming for a tailored defunctionalisation of these oxygen rich compounds. Consequently, such transformations require novel strategies concerning the development of suitable catalysts and appropriate process concepts. (orig.)

  9. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis

    OpenAIRE

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A.; Robertson, Peter K. J.; Irvine, John T. S.

    2016-01-01

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels.

  10. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis.

    Science.gov (United States)

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A; Robertson, Peter K J; Irvine, John T S

    2016-01-28

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels. PMID:26661296

  11. Hemocompatibility study of a bacterial cellulose/polyvinyl alcohol nanocomposite

    OpenAIRE

    Alexandre F. Leitão; Gupta, Swati; Silva, João P; Reviakine, I.; Gama, F. M.

    2013-01-01

    Cardiovascular disease is among the leading causes of death in the world. Grafts are usually used to treat these diseases by redirecting blood flow around occluded vessels. We previously showed bacterial cellulose (BC) is a suitable artificial alternative to commonly used autologous grafts. We found that the addition of polyvinyl alcohol (PVA) improves the mechanical properties of BC. For cardiovascular applications, hemocompatibility needs to be characterized. Here, we c...

  12. Polylactide Foams Reinforced with Wood Fibers or Microfibrillated Cellulose

    OpenAIRE

    Orhan, Münire

    2010-01-01

    The growing environmental awareness of pollution and climate change has set up newrules and regulations, which forces the industries to seek and satisfy the demand formore alternative and renewable products. Research has been launched for findingnovel lightweight materials for packaging, transportation and construction. Currently,there is an interest of finding new applications of new forms of cellulose since theyoffer low density and cost, renewability and biodegradability. The potential of ...

  13. First come, first served. Does pouring sequence matter for consumption?

    Science.gov (United States)

    Stroebele-Benschop, Nanette; Dieze, Anastasia; Hilzendegen, Carolin

    2016-10-01

    Various environmental factors associated with eating and drinking affect people's food choice and food intake. Lately, the role of tableware has been studied in more detail. The aim of this study was to determine whether pouring sequence of food components affects portion size. Study 1 invited participants to pour a beverage containing both apple juice and sparkling water. Pouring apple juice first increased juice by almost 25% compared to pouring water first. Pouring water first increased water by almost 19% compared to pouring juice first confirming our hypothesis that pouring sequence affects the ratio poured. Study 2 asked participants to prepare themselves a snack containing cereals with milk. Within-subject comparisons revealed that pouring milk before cereals significantly increased both milk and cereal amounts resulting in larger overall portion size compared to pouring cereals before adding milk. Habitual tendencies for preparing foods causing a perception bias or a perception bias itself could be possible explanations for the divergent study findings. These findings show for the first time the influence of pouring and preparation sequence on portion size. PMID:27417334

  14. Macroscopic models for single-phase flows in fractured porous medium: application to well tests; Modeles macroscopiques pour les ecoulements monophasiques en milieu poreux fracture: application aux tests de puits

    Energy Technology Data Exchange (ETDEWEB)

    Landereau, P.

    2000-12-01

    We consider pressure diffusion in fractured media, with application to well test interpretation. Using the volume averaging theory of Quintard and Whitaker, the local problem is replaced by a double-porosity large scale description. The parameters of the latter may be computed solving small scale closure problems on a representative volume. Using suitable numerical methods, we have performed a systematic study of these parameters as a function of the topology of the fracture network and matrix to fracture permeability contrast. We find that the matrix permeability plays a significant role near a percolation threshold. Next, we studied the exchange coefficient parameter, by unifying the different definitions of the literature in a single framework using a Fourier analysis. Finally, we applied our technique to well-test interpretation in fractured media by comparing large scale solutions to high resolution direct simulations. We find that at short time scale, very fine grid blocks are needed to get good accuracy. In that case, a good agreement is observed between large scale averaged results and reference simulations. (author)

  15. Bayesian methods to restore and re build images: application to gamma-graphy and to photofission tomography; Methodes bayesiennes pour la restauration et la reconstruction d`images application a la gammagraphie et a la tomographie par photofissions

    Energy Technology Data Exchange (ETDEWEB)

    Stawinski, G

    1998-10-26

    Bayesian algorithms are developed to solve inverse problems in gamma imaging and photofission tomography. The first part of this work is devoted to the modeling of our measurement systems. Two models have been found for both applications: the first one is a simple conventional model and the second one is a cascaded point process model. EM and MCMC Bayesian algorithms for image restoration and image reconstruction have been developed for these models and compared. The cascaded point process model does not improve significantly the results previously obtained by the classical model. To original approaches have been proposed, which increase the results previously obtained. The first approach uses an inhomogeneous Markov Random Field as a prior law, and makes the regularization parameter spatially vary. However, the problem of the estimation of hyper-parameters has not been solved. In the case of the deconvolution of point sources, a second approach has been proposed, which introduces a high level prior model. The picture is modeled as a list of objects, whose parameters and number are unknown. The results obtained with this method are more accurate than those obtained with the conventional Markov Random Field prior model and require less computational costs. (author)

  16. Observer design for non linear systems: application to automatic fault detection in process engineering; Synthese d'observateurs pour les systemes non lineaires. Application a la detection automatique de pannes en genie des procedes

    Energy Technology Data Exchange (ETDEWEB)

    Armanet, F.

    1999-04-01

    This thesis describes some theoretical contributions in state observer design for non linear systems and the conception of an automatic fault detector system for a petrochemical process. The first chapter is an overview of the observer theory for non linear systems. The second chapter presents a new methodology of high gain observer design for single-output U-uniformly observable systems. It consists in calculate a symmetric positive definite matrix which allows the design of an high gain observer which is exponentially converging. This observer is applied to estimate the concentrations in a perfectly mixed tank reactor with a kinetic scheme corresponding to the conversion of a product A onto a product B which is also converting onto a product C. In the third chapter, the use of high gain observer is extended for systems which are not uniformly observable but all admissible inputs are locally regularly persistent. A characterization of some of this class of inputs is given and an application for the preceding reactor illustrates this theory. The fourth chapter includes a summary of the observer used in residual generator design for linear and non linear systems. Two examples of automatic fault detector using these methods are describes. In annexed documents, a detailed study of the process modeling and the main observability properties are presented. (author)

  17. Optimization of the scintillation parameters of the lead tungstate crystals for their application in high precision electromagnetic calorimetry; Optimisation des parametres de scintillation des cristaux de tungstate de plomb pour leur application dans la calorimetrie electromagnetique de haute precision

    Energy Technology Data Exchange (ETDEWEB)

    Drobychev, G

    2000-04-12

    In the frame of this dissertation work scintillation properties of the lead tungstate crystals (PWO) and possibilities of their use were studied foreseeing their application for electromagnetic calorimetry in extreme radiation environment conditions of new colliders. The results of this work can be summarized in the following way. 1. A model of the scintillations origin in the lead tungstate crystals which includes processes influencing on the crystals radiation hardness and presence of slow components in scintillations was developed. 2. An analysis of the influences of the PWO scintillation properties changes on the parameters of the electromagnetic calorimeter was done. 3. Methods of the light collection from the large scintillation elements of complex shape made of the birefringent scintillation crystal with high refraction index and low light yield in case of signal registration by a photodetector with sensitive surface small in compare with the output face of scintillator were Studied. 4. Physical principles of the methodology of the scintillation crystals certification during their mass production foreseeing their installation into a calorimeter electromagnetic were developed. Correlations between the results of measurements of the PWO crystals parameters by different methods were found. (author)

  18. Proximal methods for the resolution of inverse problems: application to positron emission tomography; Methodes proximales pour la resolution de problemes inverses: application a la tomographie par emission de positrons

    Energy Technology Data Exchange (ETDEWEB)

    Pustelnik, N.

    2010-12-15

    The objective of this work is to propose reliable, efficient and fast methods for minimizing convex criteria, that are found in inverse problems for imagery. We focus on restoration/reconstruction problems when data is degraded with both a linear operator and noise, where the latter is not assumed to be necessarily additive.The reliability of the method is ensured through the use of proximal algorithms, the convergence of which is guaranteed when a convex criterion is considered. Efficiency is sought through the choice of criteria adapted to the noise characteristics, the linear operators and the image specificities. Of particular interest are regularization terms based on total variation and/or sparsity of signal frame coefficients. As a consequence of the use of frames, two approaches are investigated, depending on whether the analysis or the synthesis formulation is chosen. Fast processing requirements lead us to consider proximal algorithms with a parallel structure. Theoretical results are illustrated on several large size inverse problems arising in image restoration, stereoscopy, multi-spectral imagery and decomposition into texture and geometry components. We focus on a particular application, namely Positron Emission Tomography (PET), which is particularly difficult because of the presence of a projection operator combined with Poisson noise, leading to highly corrupted data. To optimize the quality of the reconstruction, we make use of the spatio-temporal characteristics of brain tissue activity. (author)

  19. KINETIKA FERMENTASI SELULOSA MURNI OLEH Trichoderma reesi QM 9414 MENJADI GLUKOSA DAN PENERAPANNYA PADA JERAMI PADI BEBAS LIGNIN [Kinetics of Pure Cellulose Fermentation by Trichoderma Reesei QM 9414 to Glucose and Its Application of on Lignin Free Rice Straw

    Directory of Open Access Journals (Sweden)

    M Iyan Sofyan

    2004-12-01

    Full Text Available The objectives of this research were: 1 to determine aeration rate and substrate concentration of pure cellulose to produce maximum glucose by Trichoderma reesei QM 9414 at 30 oC, and agitation 150 rpm; 2 to study the kinetics of pure cellulose fermentation by Trichoderma reesei QM 9414 to glucose and its implication upon fermentation of the lignin free rice straw. The experiment was arranged in factorial randomized complete design in three times replication. Treatments consisted of three levels of aeration (1,00 vvm; 1,5 vvm; 2,0 vvm and three levels of substrate concentration (0,75 ; 1,00 ; 1,25 % w/v. The results showed that at the exponential phase the average specific growth of Trichoderma reesei QM 9414 was 0,05374 hour-1, the maximum glucose product concentration of pure cellulose was 0.1644 gL-1,and the oxygen transfer was 0,0328 mg L-1 hour-1. According to t-test, the kinetics of pure cellulose fermentation model just the same as the lignin free rice straw fermentation.The enzymes produced by Trichoderma reesei QM 9414 in pure cellulose fermentation media followed the Michaelis-Menten model. The enzyme kinetic parameters were the maximum growth rate was 37x10-3 hour-1 and Michaelis-Menten constant was ½ maximum μ =17,5x10-3 hour-1. The volumetric oxygen transfer (KLa using rice straw was 0,0337 mg.hour-1. The value of KLa could be used for conversion from bioreactor at laboratory scale to commercial scale design.

  20. Plasma-enhanced synthesis of green flame retardant cellulosic materials

    Science.gov (United States)

    Totolin, Vladimir

    The natural fiber-containing fabrics and composites are more environmentally friendly, and are used in transportation (automobiles, aerospace), military applications, construction industries (ceiling paneling, partition boards), consumer products, etc. Therefore, the flammability characteristics of the composites based on polymers and natural fibers play an important role. This dissertation presents the development of plasma assisted - green flame retardant coatings for cellulosic substrates. The overall objective of this work was to generate durable flame retardant treatment on cellulosic materials. In the first approach sodium silicate layers were pre-deposited onto clean cotton substrates and cross linked using low pressure, non-equilibrium oxygen plasma. A statistical design of experiments was used to optimize the plasma parameters. The modified cotton samples were tested for flammability using an automatic 45° angle flammability test chamber. Aging tests were conducted to evaluate the coating resistance during the accelerated laundry technique. The samples revealed a high flame retardant behavior and good thermal stability proved by thermo-gravimetric analysis. In the second approach flame retardant cellulosic materials have been produced using a silicon dioxide (SiO2) network coating. SiO 2 network armor was prepared through hydrolysis and condensation of the precursor tetraethyl orthosilicate (TEOS), prior coating the substrates, and was cross linked on the surface of the substrates using atmospheric pressure plasma (APP) technique. Due to protection effects of the SiO2 network armor, the cellulosic based fibers exhibit enhanced thermal properties and improved flame retardancy. In the third approach, the TEOS/APP treatments were extended to linen fabrics. The thermal analysis showed a higher char content and a strong endothermic process of the treated samples compared with control ones, indicating a good thermal stability. Also, the surface analysis proved