bluuebunny/crossref_metadata_2025 huggingface dataset:
Parcours professionnels et professionnalisation des enseignants du secondaire : des régularités du social aux trajectoires singulières
Authors: Guibert Pascal , Lazuech Gilles
Published: May 2021

Les parcours d’insertion professionnelle des enseignants du secondaire sont explicables par un ensemble de causes qui interagissent entre elles. Si le modèle de la « vocation » n’a pas disparu, l’accès au métier et l’insertion professionnelle sont de moins en moins linéaires et de plus en plus singuliers (Dubet, 2002 ; Dubar, 2000). Cette diversité des modes d’accès au métier ne veut pas dire qu’ils ne sont pas objectivables et modélisables (Huberman, 1989 ; Périer, 2004). Dans la première partie de cet article, à partir d’une analyse statistique, nous présenterons deux modes d’entrée dans la profession puis quatre parcours-types d’insertion professionnelle (Guibert, Lazuech, Rimbert, 2008). Dans une seconde partie, il s’agira de confronter les régularités constatées aux trajectoires singulières des individus. Pour cela, à partir d’entretiens choisis dans un corpus empirique plus large, on observera comment se construisent des parcours professionnels singuliers ainsi que leur importance dans la professionnalisation des enseignants débutants.
La classe des débuts et ses épreuves : prolégomènes au processus de professionnalisation
Authors: Périer Pierre
Published: May 2021

L’objet de cet article porte sur l’analyse des premiers moments et tournants vécus par les professeurs stagiaires du secondaire à leur entrée dans le processus de professionnalisation, c’est-à-dire en responsabilité face à une classe. L’imprévisibilité et la contingence des situations d’enseignement éloignées des rôles anticipés engendrent des épreuves sous la forme de négociations, de révisions ou de deuils que les enseignants tentent, avec une réussite inégale, de surmonter. Dans la perspective de ce texte, les débuts dans le métier préfigurent, par leur diversité même, un processus d’individualisation où les subjectivités sont plus fortement engagées, sollicitées et éprouvées. Etroitement chevillées au travail des acteurs sur eux-mêmes, les trajectoires de professionnalisation naissantes n’en restent pas moins une production collective dont on interrogera le modèle d’enseignant qu’elle dessine en pointillé.
Les idéologies du territoire : des alibis pour les politiques éducatives en milieu rural ?
Authors: Alpe Yves , Fauguet Jean-Luc
Published: May 2021

Les politiques éducatives s’appuient souvent sur une vision stigmatisée du territoire rural, conçu comme un espace marqué par le retard de développement et le refus de la modernité. Ainsi se fabrique une véritable « idéologie du territoire », qui fonctionne comme un alibi : les rapports de force et les enjeux sociaux disparaissent derrière le territoire. Cette conception, largement diffusée, finit par influencer les représentations des acteurs locaux : alors que les performances scolaires des élèves ruraux sont de bon niveau, leurs trajectoires scolaires témoignent d’un « discrédit identitaire », qui influe sur leurs projets scolaires et professionnels. Sur un plan plus général, les pratiques territorialisées des acteurs locaux restent assez largement inconnues, alors qu’une meilleure compréhension du rapport au territoire pourrait améliorer l’efficacité des interventions de la puissance publique, tout particulièrement dans le domaine de l’éducation.
Culture et interculturel en psychologie : préférence pour la démarche scientifique et conséquences épistémologiques
Authors: Troadec Bertrand
Published: May 2021

La recherche interculturelle est souvent définie comme l’étude soit de la diversité culturelle soit du contact de cultures différentes. Cette définition oppose deux conceptions des relations entre cultures : leur séparation ou bien leur rencontre. Cette opposition n’apparaît pas satisfaisante d’un point de vue anthropologique et sociologique, car toute culture, conçue comme « séparée » des autres, est le produit des « rencontres » qu’elle a eu au cours de son Histoire. À partir d’analyses sociologiques des racismes qui différencient un racisme d’exclusion/séparation et un racisme d’assimilation/rencontre, on se propose de dépasser l’opposition précédente et de définir - au moins pour la psychologie - la recherche interculturelle comme la résultante d’un système complexe de relations qu’il est possible d’établir entre les principales idéologies relatives aux races, ethnies, cultures.
Pistes pour renouveler l’interculturel en éducation
Authors: Dervin Fred
Published: May 2021

Cet article prend position dans le marécage théorique, conceptuel et analytique de « l’interculturel » en en proposant une approche critique et intersubjective. Qu’il s’agisse d’éducation ou de recherche, « l’interculturel » a souvent mené à des malentendus que je déconstruirai dans une première partie, à partir de l’exemple de la didactique des langues étrangères. Ce domaine peut parfois alimenter les démarches objectivisantes et culturalistes de l’interculturel et conduire davantage au culturalisme qu’à de l’interculturel, compris ici comme phénomènes co-constructifs. Je tenterai de démontrer ensuite comment un travail systématique et réflexif à l’école pourrait permettre des interrogations sur les notions centrales de culture, identité et représentations mais aussi sur le rôle de l’Autre, des contextes d’interaction et des discours dans la co-construction de soi et de l’autre. Deux modèles de compétences interculturelles qui prennent en compte ces suggestions seront passés en revue. Deux composantes seront examinées en détail.
Des pratiques interculturelles dans les écoles des régions du Québec : un modèle à inventer ?
Authors: Laaroussi Michèle Vatz , Steinbach Marilyn
Published: May 2021

Si les pratiques interculturelles en milieu scolaire sont bien ancrées dans certaines écoles montréalaises, où la diversité ethnique et culturelle fait partie du paysage depuis de nombreuses années, il en va autrement dans les régions du Québec nouvellement exposées à cette diversification de leurs populations. Pourtant les politiques de régionalisation de l’immigration en œuvre au Québec depuis 1993, postulent un capital interculturel plus ouvert en région que dans les grandes métropoles. Comment se jouent aujourd’hui les relations interculturelles dans le monde scolaire des régions du Québec ? Quels en sont les enjeux, les éléments facilitateurs et les principaux obstacles ? Voici les questions qui guident cet article. À partir de différentes recherches portant sur les collaborations familles immigrantes-école et sur l’immigration dans les régions du Québec, l’article propose une réflexion sur les facettes de la diversité culturelle en milieu scolaire régional et sur le développement de nouveaux espaces d’interculturalité.
La dimension existentielle dans la construction du problème en recherche doctorale
Authors: Xypas Constantin , Robin Jean-Yves
Published: May 2021

À partir de l’observation de doctorants en sciences de l’éducation en particulier et en sciences humaines et sociales en général, il apparaît que le facteur existentiel assure une fonction complexe : il est à la fois ce qui mobilise l’intérêt du chercheur et le conduit à poser le problème, et en même temps ce qui mobilise ses résistances intellectuelles et empêche la rupture nécessaire avec le sens commun, sans laquelle le problème ne peut être construit. Par quel accompagnement des doctorants favoriser la maturation intellectuelle et émotionnelle du projet afin d’atteindre la rupture nécessaire avec le sens commun ?
Travail enseignant et transmission scolaire
Authors: Rey Bernard
Published: May 2021

Cet article veut suggérer qu’on ne peut analyser le travail enseignant sans se référer à la forme anthropologique de transmission dans laquelle il s’effectue. En effet la transmission des pratiques sociales d’une génération à une autre s’est organisée, dans nos sociétés modernes, principalement sous la forme « didactisée ». Cela signifie que ces pratiques ne sont pas transmises dans l’action et dans les conditions ordinaires de leur exercice, mais dans un lieu isolé, l’école, et à travers des discours. Nous montrons en quoi ces discours tendent à prendre la forme de textes. Or l’accès au texte constitue une difficulté majeure pour les élèves, car il impose une manière de donner du sens aux énoncés qui leur est inhabituelle, voire inconnue. Dès lors, le travail de l’enseignant consiste à inventer différents moyens pour résoudre ou contourner cette difficulté. Mais il s’avère que chacun de ces moyens, tout en résolvant partiellement le problème, engendre de nouvelles difficultés, ce qui rend le travail enseignant uniformément dramatique.
Hétérogénéité, tensions implicites et influences sur les formats de travail proposés aux élèves dans l’enseignement/apprentissage de la langue première à l’école
Authors: Delarue-Breton Catherine
Published: May 2021

Le rapport entre les recherches en éducation et les formats de travail proposés aux élèves au sein de la classe conserve, en ce qui concerne l’enseignement/apprentissage de la langue première, une certaine opacité. Occupant une position intermédiaire entre didactiques et formats de travail scolaires, les pratiques enseignantes, confrontées au sein de la classe à un réel hétérogène et mouvant, mais également assujetties à des prescriptions souvent peu homogènes, ajoutent une dimension centrale à la complexité de l’analyse. Nous proposons ici d’évoquer quelques-uns des phénomènes récurrents susceptibles de donner forme à la pratique pédagogique, et, par conséquent, d’infléchir les formats de travail proposés aux élèves. Ceux-ci s’inscrivent dans une hétérogénéité ou dans des tensions risquant, parce qu’elles s’exercent à l’insu des acteurs, de nuire à la cohérence de leurs interventions ; elles se situent donc, tout en n’y étant pas complètement étrangères, en deçà des querelles explicites qui donnent parfois lieu dans la sphère sociale à des polémiques, et agissent d’une manière plus souterraine, mais non moins puissante. Certaines d’entre elles sont inhérentes à l’objet enseigné, la langue première ; d’autres sont davantage liées à la spécificité de la relation pédagogique, et concernent notamment la mise en œuvre des dispositifs d’apprentissage.
Une situation ouverte en mathématiques : rapports dialectiques entre Théorie - Expérimentation - Contingence
Authors: Notaro Christine Del
Published: May 2021

Cet article prend comme point de départ des résultats de recherche (Del Notaro, 2010) et se propose de décrire quelques phénomènes observés dans la contingence de la pratique des enseignants primaires, en mathématiques. L’observation des pratiques effectives nous a permis de mettre en évidence un phénomène dans notre thèse de doctorat, que nous avons nommé la saturation du milieu. Nous montrons comment ce phénomène contraint les pratiques et présentons la manière dont nous avons procédé et qui a contribué à sortir de la confusion. Le dispositif mis en place est à envisager comme une interaction de connaissances entre l’expérimentateur et les élèves : les jeux de tâches. Nous exposons en outre, comment, par un effet de transposition didactique, une situation apparemment ouverte se retrouve confinée dans un cahier à l’usage des enseignants au lieu de circuler entre les différents mondes auxquels elle est pourtant destinée : tout d’abord, celui dont elle est issue, la noosphère, ensuite celui de l’école pour qui elle a été conçue, puis celui de la formation, qui tente de l’exploiter, et enfin celui de la recherche, qui l’utilise avec les élèves et en analyse les effets.
L’impact réel des technologies de l’information et de la communication sur la forme scolaire
Authors: Coen Pierre-François
Published: May 2021

L’avènement de l’ère numérique bouleverse le monde d’aujourd’hui. L’utilisation généralisée des ordinateurs et d’Internet en particulier modifie complètement les rapports que les gens entretiennent entre eux mais également ceux qu’ils ont avec l’information et le savoir. L’école n’échappe pas à ces bouleversements et de nombreux pays ont mis en place d’importants programmes visant l’intégration des TICE. Cette intégration ne va pas sans bousculer les pratiques d’enseignement et la forme scolaire. Cet article se propose d’examiner les impacts réels que les TICE ont sur quelques aspects de la forme scolaire tels que les savoirs et leur médiation, les apprentissages dans ces environnements nouveaux, les rôles tenus par les différents acteurs et enfin la transformation des espaces dédiés aux processus d’enseignement-apprentissage.
Éléments pour une histoire de l’éducation à la citoyenneté : de l’école publique française au lycée, quels enjeux ?
Authors: Chauvigné Céline , Étienne Richard , Clavier Loïc
Published: May 2021

L'éducation à la citoyenneté est à l'image de notre société, aux prises avec les fluctuations sociales, politiques et économiques du moment. De l'instruction civique et morale au service de l'État, au XIXe siècle, à l'individualisme démocratique de ces dernières années, la citoyenneté et son enseignement sont le reflet de tensions qui envahissent l'École. Après presque un siècle de stabilité, leur place et leurs enjeux en sont continuellement bouleversés. Cet article essaie de mettre en lumière quatre périodes qui ont marqué l’histoire de cette discipline, en s’appuyant sur les grandes conceptions et applications de l'éducation à la citoyenneté en milieu scolaire, dans sa complexité et son instabilité.
La difficile construction de l’identité professionnelle des professeurs-documentalistes de l’enseignement agricole public
Authors: Marcel Jean-François , Gardiès Cécile
Published: May 2021

La double composante du métier de professeurs documentalistes de l’enseignement agricole invite à interroger les processus d’élaboration de l’identité professionnelle. D’un point de vue théorique, notre analyse s’appuie sur les deux processus qui concourent à la production des identités au travers d’un mécanisme commun, la « négociation identitaire ». Sont également convoqués « les catégories d’analyse de l’identité » et les « formes élémentaires de l’identité professionnelle » (Dubar). Le positionnement des « profs-docs » par rapport aux autres professeurs dans l’établissement est appréhendé à partir de la distinction proposée par Strauss entre les « segments » et les sous-ensembles que constituent les « cercles de confraternité ». Une recherche-action ayant pour objectif d’analyser les activités professionnelles du « prof-doc » « oubliées » dans les prescriptions permet de dégager trois éléments d’analyse de la construction de l’identité professionnelle : le CDI comme espace de transaction subjective, les « profs-docs » comme cercle de confraternité et enfin le rapport au métier comme espace de négociation identitaire. Trois figures identitaires interdépendantes, la figure tutélaire de Janus, la figure de Sisyphe en arrière-plan, et enfin la figure émergente du résistant, se positionnent entre « l’identité héritée », « l’identité attribuée » et « l’identité visée » mais en attestant clairement de la tension entre ces pôles.
Polymer Nanocomposites Coating for Anticorrosion Application
Authors: Kumar Sudheer , Krishnan Sukhila , Samal Sushanta Kumar , Mohanty Smita , Nayak Sanjay Kumar
Published: May 2021

Corrosion is the foremost reason for the deterioration of metallic components used in harsh environments and hence research on the development of an innovative protective system with admirable performance has become a subject of leading importance. Currently, chromates free organic or the polymer coatings on the metal substrate bestow an efficient barrier amongst the metal and inhibit corrosion and save the environment. Researchers have involved in the development of polymer coating containing nanoparticles because reinforcement of nanoparticles decreases the porosity and provides a zig-zag diffusion path which in turn forms barrier layer on the metal surface to protect the metal from the harmful corrosive species. This present chapter deliberates the application of polymer-based nanocomposite coating to mitigate the corrosion of metals against harsh environment. This chapter covers the utilization of carbon-based nanoparticles, inorganic nanoparticle, conductive polymer, self-heling polymer, etc., and could shows a new insight to for anti-corrosive metal surface protective coating.
Fabrication of Metal Oxide-Biopolymer Nanocomposite for Water Defluoridation
Authors: Andala Dickson Mubera , Mobegi Erick , Nawiri Mildred , Otieno Geoffrey
Published: May 2021

Fluoride contamination in groundwater affects about 150 million people worldwide. In this study, the authors focused on synthesizing biopolymer metal oxide nanocomposite for fluoride removal. Nanocomposite material was done using SEM. As(V), Al, Ti, Zr, and Fe water samples were analysed by ICP-MS (inductively coupled plasma-mass spectrometry). Fluoride level was determined using the standard method – Ion-Selective Electrode method. Preliminary results indicate arsenic (V) removal was below the 10 ppb and fluoride less than 1.5 ppm as prescribed by WHO. The removal efficiency was after 60-70 minutes with recyclability of 11 cycles. The nanocomposite worked well in all pH ranges 6.5-8.5. A filter cartridge biopolymer metal oxide nanocomposite constituting of template aluminium homogenized in the aggregated network of chitosan was developed as an adsorbent for fluoride from the water with better adsorption limit.
Influence of Nano-Particle Additives on Bio-Diesel-Fuelled CI Engines
Authors: A. Tamilvanan , Balamurugan K. , Mohanraj T. , Selvakumar P. , Ashok B. , Sakthivel R.
Published: May 2021

Biodiesel is proven to be the best substitute for petroleum-based conventional diesel fuel in existing engines with or without minor engine modifications. The performance characteristics of biodiesel as a fuel in CI engine are slightly lower than that of diesel fuel. The emission characteristics of biodiesel are better than diesel fuel except NOX emission. The thermo-physical properties of biodiesel are improved by suspending the nano metal particles in the biodiesel, which make them an observable choice for the use of nanoparticles-added fuels in CI engine. High surface area of nanoparticles that promotes higher operating pressure and heat transfer rates that further quicken the combustion process by providing better oxidation. Thus, it has been inferred that addition of nanoparticles as an additive to biodiesel fuel blends in diesel engines and its effects on performance, combustion, and emission characteristics are discussed in this chapter.
Mechanisms of Action of Nanoparticles in Living Systems
Authors: Rawat Madhu , Yadukrishnan P.  , Kumar Nitin
Published: May 2021

Nanoparticles are being formed continuously in processes like mineralization, natural calamities, and geological recycling of matter and present naturally in the environment. In the recent past, nanoparticles and their applications have become an extensive topic of research. Application of nanomaterials in different industries will surely enhance the chances of discharge of nanoparticles into the environment. So, a number of studies have been performed to explore the mode of action of nanoparticles on living organisms and their surroundings. The most reported modes of action of nanoparticles are antimicrobial activity, ROS-induced cytotoxicity, genotoxicity, plant growth promotion, etc. It has been successfully demonstrated that actions of nanoparticles are governed by their size, shape, dose, and concentration. However, a complete mechanism of action of nanoparticles has not been known. The present chapter focuses on the highlights of the mechanisms behind the mode of action of nanoparticles in plants and microorganisms.
Nanocomposites for Space Applications
Authors: Vargas-Bernal Rafael , Tecpoyotl-Torres Margarita
Published: May 2021

A review on the advances achieved in the last 25 years in the development of hybrid nanocomposites based on polymer matrix for aerospace applications is presented here. The chapter analyzes the state-of-the-art strategies used in the design of materials that support the different conditions of the space environment. These materials are aimed primarily at structural applications, electromagnetic interference shielding, self-sensing, and self-healing, although they are not restricted to these applications. The introduction of metallic, ceramic, carbon-based nanomaterials such as carbon nanotubes and graphene, as well as two-dimensional materials have been used with a successful impact. Despite the significant advances that have been reached, much work must be done to achieve complete reliability for all properties required to protect the systems against the hazardous conditions found in space. Therefore, futuristic visions of the actions that must be carried out are raised in this chapter.
Effect of Fe Doping on the Structural, Electrical and Magnetic Properties of Perovskite La0.7Ca0.3Mn1-xFexO 3 (X = 0, 0.01, 0.03 and 0.05)
Authors: Nik-Jaafar Nor Azah , Abd-Shukor Roslan , Kamarudin Muhammad Aizat
Published: May 2021

The effect of Fe-substitution at the Mn-site in La0.7Ca0.3Mn1-xFexO3 (x = 0, 0.01, 0.03 and 0.05) on its structure, electrical and magnetic properties has been studied. These properties were investigated via X-ray diffraction (XRD) analysis, temperature-dependent resistance measurements and temperature-dependent AC magnetic susceptibility measurements. XRD analysis showed all samples are single phase materials. Temperature dependent resistance measurements between 30–300 K showed all samples to undergo insulator-metal transition as temperature decreases. Increase in Fe doping for x = 0, 0.01, 0.03 and 0.05 caused the transition temperature TIM to decrease from 257 K, 244 K, 205 K and 162 K respectively. The magnetic susceptibility measurements showed the samples to exhibit paramagnetic to ferromagnetic transition as temperature decreased. Increase in Fe substitution x at the Mn-site progressively decreased the Curie temperature TC from 250 K at x = 0 to 170 K at x = 0.05.
Effect of Samarium Ions on Physical and Optical Properties of Zinc Borotellurite Glass System
Authors: Mohd Rafien Siti Nasuha , Kasim Azman , Yahya Norihan , Hashim Azhan , Wan Razali Wan Aizuddin
Published: May 2021

Modifying the physical and optical properties of zinc borotellurite glasses by controlling rare earth (RE) doping is important in order to obtain high quality glass. In this study, Samarium (Sm3+) doped zinc borotellurite glasses were successfully fabricated by using conventional melt-quenching technique with chemical composition (where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%). The physical properties by mean of their density as well as molar volume were measured while the optical properties have been studied through UV-Vis spectroscopy in order to determine the optical band gap (Eopt) and Urbach energy (ΔΕ) of the glass system. Optical absorption spectra of the glass samples were recorded in the range 350 nm - 750 nm at room temperature. The amorphous nature of the glass was confirmed from X-ray diffraction techniques. The density and molar volume of the glass samples were found to vary with respect to Sm3+ ions content. The value of optical band gap, Eopt lies between 2.605 eV to 2.982 eV for the direct transition and 2.768 eV to 3.198 eV for the indirect transition respectively. Meanwhile, the Urbach energy, ΔE was observed in the range of 0.112 eV to 0.694 eV respectively. The physical and optical properties were found to be strongly affected by the varying concentration of Sm3+ ions. Some other results will be analysed and discussed in detail.
Fabrication of Silica (SiO2) Foam from Rice Husk Ash (RHA): Effects of Solid Loadings
Authors: Muda Rizamarhaiza , Rahman Hamimah Abdul , Azmi Mohd Azham , Ahmad Sufizar , Mahzan Shahruddin , Taib Hariati
Published: May 2021

Silica (SiO2) foams have been widely applied in numerous fields, mainly filters and catalysts supports, due to their characteristics of high permeability, high porosity and specific surface area. In this study, foams of SiO2 from rice husk ash (RHA) was fabricated via polymeric sponge replication method. Polymeric foam initially was used as template and dipped into SiO2 slurry followed by drying and sintering to yield the replica of the original polymeric foam. Different solid loadings of SiO2 as-derived from RHA (20 to 35 wt. %) slurry and sintering temperature of 1150 °C were applied. Phase identification and chemical composition of the green and sintered foams were conducted using X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF). Morphological observations were performed using Scanning Electron Microscopy (SEM). Density and porosity of the SiO2 foams were characterized using Archimedes method. Compressive strengths of the foams were determined as per ASTM C773-88 (1999). XRD analyses confirmed that the SiO2 as derived from the RHA were of tridymite and cristobalite phases with as high as 93% purity, as confirmed by XRF analyses. The density of SiO2 foams fabricated was in the range of 0.614 to 0.989 g/cm3, whereas the porosity values was in the range of 70% to 82%%. Compressive strengths were found to increase from 0.05 to 0.30 MPa respectively, proportionate with the increased SiO2 solid loading. Excellent properties of the SiO2 foams definitely signifies that the polymeric replication method is indeed a promising technique for SiO2 as derived from RHA foam fabrication.
Assessment of Magnetic Properties between Fe and Ni Doped ZnO Nanoparticles Synthesized by Microwave Assisted Synthesis Method
Authors: Abdullahi Sabiu Said , Galadanci Garba Shehu Musa , Saiden Norlaily Mohd , Liew Josephine Ying Chyi
Published: May 2021

The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. MxZn1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.
Microcrystalline Cellulose as Graphite Exfoliation Agent and its Effect on Electrical Conductivity
Authors: Azmi Amirul Hadi , Abd Rahman Shaharin Fadzli , Zainal Abidin Mastura Shafinaz
Published: May 2021

Graphene has drawn a lot of attention as a promising material for a conductive ink due to its high electrical conductivity and abundant source. Selection of solvent for ink formulation is crucial to obtain the desired result. In this work, microcrystal cellulose solution is investigated as alternative solvent for conductive ink formulation. Although the viability of the microcrystal cellulose solution was already presented in other works, further thorough and systematic study is highly required. Cellulose solution was prepared using microcrystalline cellulose and sodium hydroxide aqueous solution. Dispersions with different graphite-to-cellulose ratio were prepared. The exfoliation process was for sonication times of 8, 16, 24 and 32 hours. For Raman spectroscopy and 4-point probe measurement, graphene thin film was formed by drop-casting 20μl dispersion on glossy paper. Sample with low graphite-to-cellulose ratio exhibited more significant reduction in unexfoliated graphite content over the sonication time. The sufficient amount of cellulose in the dispersion leads to more effective exfoliation process. According to analysis on the Raman spectra, the exfoliated graphite could be classified as few-layer graphene with low defect content. The drop-casted thin film from dispersion with ratio of 20:1 showed sheet resistance lesser than 100 Ω/sq. The obtained results confirmed the effectiveness of microcrystal cellulose as the agent for exfoliation process.
Synthesis of Calcium/Aluminium-Ciprofloxacin-Layered Double Hydroxide for a New Antibacterial Drug Formulation
Authors: Jadam Monica Limau , Jubri Z. , Sarijo Siti Halimah
Published: May 2021

An antibacterial drug, ciprofloxacin (Cipro) was successfully encapsulated into Ca/Al-layered double hydroxide (CLDH) with molar ratio Ca/Al = 3:1 (R3) by anion exchange method at optimum concentration of 0.2 M Cipro. The successful intercalation was confirmed by patterns analysis of powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), elemental analysis (CHNS) and accelerated surface area and porosity (ASAP) analysis. Basal spacing of CLDH synthesized in this study is 8.7 Å. Due to the inclusion of Cipro into the layered CLDH, basal spacing expanded to 16.2 Å in Ca/Al-Cipro-LDH (CCLDH) compare to in CLDH. The FTIR spectra of the hybrid nanocomposite show resemblance peaks of the layered double hydroxide (LDH) and Cipro, indicating the inclusion of the drug anion into the LDH interlamellae. The percentage loading of Cipro calculated from the data obtained from CHNS is 75.9% (w/w). This shows that Ca/Al-layered double hydroxide, CLDH has prospective application as the host for ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid), an antibacterial drug for a novel drug delivery formulation.
Conversion of Bacterial Cellulose to Cellulose Nitrate with High Nitrogen Content as Propellant Ingredient
Authors: Jamal Siti Hasnawati , Jori Roslan Nursyafiqah , Ahmad Shah Noor Aisyah , Mohd Noor Siti Aminah , Khim Ong Keat , Wan Yunus Wan Md Zin
Published: May 2021

Cellulose nitrate has attracted great interest amongst researchers due to its uses in wide range of products including paint and gun propellant. Therefore, this work focuses on the synthesis of cellulose nitrate from two different sources of cellulose; plant and bacterial, in order to obtain high percentage of nitrogen content hence suitable for propellant application. The synthesis of cellulose nitrate was carried out via nitration method using nata de coco and kapok (Ceiba pentadra L) as a raw materials of cellulose. The samples were then characterized by elemental analysis, fourier transform infrared (FTIR) spectroscopy, x-ray diffraction and surface electron morphology (SEM). FTIR analysis showed the presence of NO2 groups in both nitrocellulose proving that nitrocellulose was successfully synthesized by nitration method even though it was produced from different sources of cellulose. It is also showed nitrocellulose with high percentage of nitrogen content was obtained from bacterial cellulose, 12.69% rather than plant cellulose.
Structural and Dielectric Analysis of La0.88Bi0.12Mn0.80Ni0.20O3 Composite
Authors: Sinin Aaliyawani Ezzerin , Primus Walter Charles , Talib Zainal Abidin , Kien Chen Soo , Shaari Abdul Halim , Sinin Hamdan , Zainuddin Zalita
Published: May 2021

Composite La0.88Bi0.12Mn0.80Ni0.20O3 was synthesized using the conventional solid-state reaction method with sintering temperature of 1200 °C for 12 hours and the dielectric properties investigated. The X-ray diffraction result shows that the composite has a rhombohedral structure with lattice parameter of a = b = c = 5.5136 Ǻ. Scanning electron microscope shows grains with approximately from 0.8 to 5.4 μm in size with presence of voids. The dielectric permittivity, εʹ and dielectric loss, εʺ were measured in the range of 298 K to 473 K where both are temperature and frequency dependent. At 1 kHz to 100 kHz, the εʹ is around 10000 and the dielectric loss tangent, tan δ is below 1.5. The electric behavior of this composite is best represented by Quasi-dc model which consists of two universal capacitors in parallel. Parameters value from the fitting indicated that high correlations of electrons between inter and intra-clusters. The activation energy, Ea calculated from the conductivity of the sample gives a value of 0.116 eV. Vibrating sample magnetometer shows that the La0.88Bi0.12Mn0.80Ni0.20O3 has a magnetic coercivity, Hc of 36.109 G and retentivity, Br, valued 2.7504 x 10-3 emu/g.
Localized Deep and Shallow Traps of α-Peaks from Thermally Stimulated Current (TSC) Measurement on Thermoplastic Polymers
Authors: Halim Norhana Abdul , Demon Siti Zulaikha Ngah , Abdullah Norli , Ahmad Nurazlin , Abidin Zul Hazrin Zainal
Published: May 2021

In this paper, trap levels around the glass transition temperature (Tg) of polymers have been characterized using Thermally Stimulated Current (TSC) technique. Deconvolution on α-peaks of the Tg for PE (-104 °C), plasticized PVC (-35 °C), PMMA (90 °C) and PET (96 °C) were carried out based on the first-order kinetic theory for non-Debye relaxation. Using temperature, T from TSC experimental data, we have successfully separated the α-peaks of the thermoplastic polymers. It is found that the complex curve of α-peaks can composed of four (4) to eight (8) sub peaks. Dominant sub peaks were identified at Tmax = -105 °C, -34 °C, 89 °C and 92 °C for PE, pPVC, PMMA and PET, respectively. These peaks show activation energy, Ea of shallow and deep trap centers ranged from 0.3 eV to 4.6 Ev where they represent the depolarization of localized dipoles and space charges relaxations in the polymers.
Electrical and Electrochemical Studies of Polymer Gel Electrolytes Based on Agarose-LiBOB and P(VP-co-VAc)-LiBOB
Authors: Ari Muhammad Syahir Sak , Abidin Siti Zafirah Zainal , Taib Mohamad Fariz Mohamad , Yahya Muhd Zu Azhan
Published: May 2021

This study focuses on preparation and characterization of polymer gel electrolytes (PGEs) based on agarose–LiBOB–DMSO and poly(1-vinylpyrrolidone-co-vinyl acetate)–LiBOB–DMSO. Two systems of PGEs were prepared by dissolving a different amount (1-8 wt.%) of agarose and (1-8 wt.%) P(VP-co-VAc) as host polymer in 0.8 M of LiBOB–DMSO solution. The addition of host polymer into 0.8 M of LiBOB–DMSO solution will result an optimum conductivity which is 6.91 x 10-3 S.cm-1 for agarose–LiBOB–DMSO system and 7.83 x 10-3 S.cm-1 for P(VP-co-VAc)–LiBOB–DMSO system. In the temperature range of conductivity studies discovered that the agarose–LiBOB–DMSO and P(VP-co-VAc)–LiBOB–DMSO polymer gel electrolytes abide by Arrhenius rule indicating that this PGEs could run at elevated temperature conditions. Furthermore, lithium transference number confirms that both electrolyte systems have 0.03 and 0.12 respectively at room temperature (298 K). Linear sweep voltammetry (LSV) measurements demonstrate the agarose–LiBOB–DMSO system has a potential of 4.26 V and P(VP-co-VAc)–LiBOB–DMSO system has a potential of 4.50 V which is good in electrochemical stability.
Structural and Conductivity of NiO-BCZY Anode Functional Layer for Proton Conducting Fuel Cell
Authors: Malik Lidyayatty Abdul , Mazlan Nurul Waheeda , Mohd Tahir Nur Nadhihah , Hassan Oskar Hasdinor , Jani Abdul Mutalib Md , Osman Nafisah
Published: May 2021

The main objective of this study is to perform a structural analysis of NiO-BCZY anode functional layer (AFL) with different weight ratio (NiO:BCZY = 20:80 and 40:60). NiO commercial powder and in-house developed BCZY synthesized by a sol-gel method are mixed and ground and then sintered at 1450° C for 5 hours to produce AFL powder. The single-cell (anode | CG-AFL| electrolyte | cathode) is fabricated with the anode substrates firstly die-pressed, then compositionally gradient anode functional layer (CG-AFL) and spin-coated with electrolyte thin film, accordingly. Structural characterization of AFL powder and conductivity of the single cell is performed using room temperature X-ray diffraction (XRD) and in-house developed electrochemical impedance spectroscopy (EIS) test station, respectively. Rietveld refinement analysis of the XRD data confirms the high purity single phase of NiO and BCZY. Both NiO and BCZY show a cubic crystal structure and each belongs to space group Fm-3m and Pm-3m, respectively. The lattice parameter (a = b = c) of NiO and BCZY are about 4.1818 Å3 and 4.3433 Å3 for 20NiO-80BCZY and 4.1825 Å3 and 4.3439 Å3 for 40NiO-60BCZY. EIS results show ohmic resistance (RS) and polarization resistance (RP) of the single cell are 14.8 and 16.23 Ωcm2 at 800 °C, respectively.
Vibrational Spectroscopy Analysis of Oligothiophene Blend Film
Authors: Demon Siti Zulaikha Ngah , Poad Nursaadah Ahmad
Published: May 2021

One of the challenges in fabricating organic semiconductor thin film is to produce bettermolecular ordering that compromise its electronic properties. Molecular ordering of amorphous thin film can be improved in many ways. Here, high molecular weight polylactic acid (PLA) is introduced as binding matrix to promote 3'''-didodecyl-2,2':5',2'':5'',2'''-quaterthiophene (4T) film’s homogeinity across indium tin oxide (ITO) surface. Molecular ordering of the spin coated biodegradable PLA and 4T blend film processed at ambient atmosphere was studied using two vibrational spectroscopy methods. The complementary analysis of infrared absorption spectrum and Raman spectrum had identified several vibrational modes contributed by thiophene rings and alkyl functional groups. The Raman analysis implied there is a slight change of thiophene ringsʼ molecular orientation due to compressive stress after introduction of polymer. Microscopic characteristics of oligothiophenes especially at the π-π conjugated backbones contained crucial information in order to exploit the oligothiophene as flexible electronics devices.
Influence of Various Target to Substrate Distances on the Structural and Optical Properties of Sputtered Gd-Doped ZnO Thin Films
Authors: Raship Nur Amaliyana , Tawil Siti Nooraya Mohd , Nayan Nafarizal , Ismail Khadijah , Tahan Muliana , Bakri Anis Suhaili
Published: May 2021

The effect of various target to substrate distance on the physical properties of sputtered Gd-doped ZnO thin films were investigated. The thin films with three distances between a target to substrate ranged from 12.0, 13.5 and 15.0 cm were deposited by a dual-target sputtering method. All the thin film properties were characterized using x-ray diffraction, atomic force microscope, energy dispersive x-ray analysis and ultra-violet visible spectrophotometer. The sharp and intense peak of (002) was observed for a sample with the target to substrate distance of 13.5 cm which indicated good crystallinity as compared to other samples. Gd incorporations of 3 at% in ZnO films were further confirmed via the energy dispersive x-ray analysis. AFM images revealed that the surface topology Gd-doped ZnO thin film have a smooth and uniform surface. The transmittance was above 90 % and slightly decrease with the increase of target to substrate distance. The bandgap value was static at 3.14 eV for all the 12.0, 13.5 and 15.0 cm of various target to substrate distances.
Structural and Optical Properties of BiFeO3 via Polymer-Assisted Hydrothermal Synthesis under Different Weight of Chitosan
Authors: Sazali Muhammad Safwan , Yaakob Muhamad Kamil , Mamat Mohamad Hafiz , Hassan Oskar Hasdinor , Yahya Muhd Zu Azhan
Published: May 2021

In this work, single phase Bismuth Ferrite, BiFeO3 was successfully synthesized by using hydrothermal method assisted with different weight (0.24 g, 0.36 g and 0.48 g) of Chitosan. Potassium hydroxide (KOH) were used as a mineralizer during the synthesis process for the precipitation. The samples were characterized for different properties such as structural and optical properties, and were then compared with previous works. The X-ray diffraction data for all the samples showed that the samples had a single phase belonging to R3c space group with perovskite rhombohedral structure at diffraction angle 32.0° to 32.5° even though the slight presence of secondary phase at diffraction angle 28° was detected. Scanning electron microscope revealed a decrement in particle size as the weight of Chitosan increased indicating effective used of Chitosan in controlling the agglomeration of the particles. All samples BiFeO3 assisted with and without Chitosan showed significant enhancement in energy gap where the obtained results showed a small energy gap values ranging from ~1.22 eV to ~1.88 eV determined from UV-vis absorbance characterization. Therefore, by the addition of Chitosan, the properties of BiFeO3 such as structural and optical have changed as well as preventing from the particle to agglomerate.
Comparative Spectroscopic Studies on Luminescence Performance of Er3+ Doped Tellurite Glass Embedded with Different Nanoparticles (Ag Co and Fe) at 0.55 μm Emission
Authors: Yaacob Syariffah Nurathirah Syed , Sahar M.R. , Noor Faizani Mohd , Rodin Nur Liyana Amiar , Zain Siti Khadijah Mohd , Buchori Puzi Anigrahawti , Aziz Siti Maisarah , Yusoff Nurulhuda Mohammad , Sulhadi Sulhadi
Published: May 2021

The spectroscopic performance of Er3+ doped glass at 0.55 mm emission contain different nanoparticles NPs have been comparatively evaluated. Glass containing 1.0 mol % of Er3+ doped with different NPs (Ag, Co and Fe ) have been prepared using melt quenching technique. X-ray diffraction analysis reveals the all the prepared samples are amorphous. The UV-Vis absorption spectra of all glasses show several prominent peaks at 525 nm, 660 nm, 801nm, 982 nm and 959 nm due to transition from ground state 4I15/2 to different excited of 2H11/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2. The emission of Er3+ at 0.55 mm for glass contain Ag NP shows significant enhancement about 3 folds up to 0.6 mol%. On the other hand, the emission of Er3+ at 0.55 mm for glass containing Fe NPs and Co NPs intensely quench probably due to the energy-transfer from Er3+ ion to NPs and magnetic contributions.
Optimum Lasing Cavity for Erbium Doped Zinc Tellurite Glass Rods Embedded with Ag Nanoparticles
Authors: Adnan Nur Aina Mardia , Sahar M.R. , Sazali E.S.
Published: May 2021

A laser cavity was constructed for excitation of erbium doped zinc tellurite glass rods embedded with various concentration of Ag nanoparticles. Central to the system is a Xenon flashlamp for optical pumping, and mirrors to amplify the light waves. The amorphousity of the glass rod was studied by X-ray diffraction and the existence of silver nanoparticles inside the glass was confirmed by high resolution transmission electron microscopy analysis. The photoluminescence properties and differential thermal analysis curve of the samples confirmed the compatibility of the rods as gain medium. The rods were successfully fabricated and incorporated inside the laser cavity. The output of the laser with erbium doped zinc tellurite glass rods embedded with Ag nanoparticles was characterized via spectrum analyser and was found that the spectrum dominated at line 473 nm and 506 nm. The beam profiler was utilized to detect and display the laser beam in 3D.
A Full-Ocean-Depth Sampler for Hadal Microbes Based on Multistage Membrane Filters With In-Situ Preservation
Authors: Chen Jiawang , He Weitao , Zhou Peng , Fang Jiasong , Zhang Dahai , Cao Chen
Published: May 2021

Abstract In order to obtain high-quality microbial samples from the hadal zone, which has a depth of over 6,000 m, a full-ocean-depth sampler with the function of in-situ filtration and preservation was developed. A flow pump and several membrane filters were used for in-situ
filtration under the sea. With a multistage filtering structure, the microbes can be initially screened according to their sizes. To avoid the degradation of microbial ribonucleic acid (RNA), a special structure was designed to inject the RNAlater solution into the samples immediately after
the filtration. The sampler was tested in our laboratory and deployed during Mariana TS-15 in 2019. It was installed on a hadal lander of Shanghai Ocean University and deployed at MBR02 (11.371°N, 142.587°E, 10,931 m) in the Mariana Trench. A total of 20 L of in-situ seawater was filtered,
and membranes with pore sizes of 3 and 0.2 μm were preserved. The study is expected to provide important support for the establishment of a hadal microbial gene pool.
Fish Tracking Based on Feature Fusion and Scale Adaptation in a Real-World Underwater Environment
Authors: Zou Li , Zhao Meng , Cao Fangfang , Zan Shiliang , Cheng Xuezhen , Liu Xiaofeng
Published: May 2021

Abstract Fish tracking is an important component of analyzing fish behavior and estimating fish population density. Due to the high degree of freedom of fish motion as well as the complex natural underwater environment, most existing object tracking methods are not ideal
for fish tracking. In this paper, a fish tracking method based on feature fusion and scale adaptation is proposed, which is built on a kernelized correlation filter (KCF) to achieve accurate and rapid tracking. The proposed method mainly focuses on feature selection and scale estimation in
the KCF framework. In feature selection, the color-naming feature and the histogram of oriented gradients feature are fused to improve the fish appearance model and reduce the influence of the high degree of freedom of fish motion and the complex natural underwater environment. In the scale
estimation, an adaptive scale estimation scheme is employed to adapt the fish scale variation by learning a 1-D scale correlation filter. The experimental results show that the proposed method is effective and accurate for fish tracking in real-world underwater environments.
Indirect Fault Diagnosis of Fixed Marine Observing Buoy Based on Bayesian Network
Authors: Yang Shujia , Wang Yi , Jiang Min , Ren Wei , Gao Yanbo
Published: May 2021

Abstract Fault diagnosis of a fixed marine observing buoy (FMOB) is important for ensuring the reliability of an ocean observing system. Aiming at the difficulty that most FMOB instruments lack direct operational status information in fault diagnosis, an indirect fault diagnosis
method based on a Bayesian network (BN) for FMOBs is presented, through which the ocean observing series collected by the FMOB are effectively utilized and analyzed for fault diagnosis of FMOB equipment. The ocean observing series not only reflects the characteristics of the marine environment
but also includes the operating status of FMOBs. Based on the analysis of an ocean observing series, the different fault symptoms of FMOBs are confirmed. According to the BN theory, the indirect fault diagnosis model is developed. The model structure is defined based on a comprehensive analysis
of the causal relationships among faults and their symptoms. The model parameters are estimated according to experts' knowledge and statistical analysis of historical data. Three typical fault cases of FMOBs are selected for verifying the method. The results show that the BN-based indirect
fault diagnosis method is reliable and effective for fault diagnosis of an FMOB even when the fault diagnosis evidence is incomplete and uncertain. Furthermore, this approach can work in a real-time way and help technicians to take effective measures to avoid big losses.