bluuebunny/crossref_metadata_2025 huggingface dataset:
L'expérience de pensée au péril de la fiction : Le cas de la correspondance entre Leibniz et Papin
Authors: Rey Anne-Lise
Published: February 2014

Cet article analyse, dans le cadre de la correspondance entre Gottfried Wilhelm Leibniz et Denis Papin, le recours à l’expérience de pensée comme modalité de résolution de la controverse. La controverse engagée d’abord publiquement entre Leibniz et Papin porte sur l’estimation de la puissance motrice. Mon hypothèse interprétative est que l’expérience de pensée est un moyen de construire un territoire dialogique commun entre des protagonistes engagés dans des philosophies naturelles bien différentes et par là de résoudre, pour un temps, le conflit.
Arago, Biot et Fresnel expliquent la polarisation rotatoire
Authors: Leclercq Frédéric
Published: February 2014

François Arago, Jean-Baptiste Biot et Augustin Fresnel ont étudié successivement la polarisation rotatoire à partir de recherches antérieures sur la polarisation chromatique. Mais le premier phénomène est peut-être celui qui révèle le mieux les limites de la théorie corpusculaire et toutes les potentialités de la théorie rivale des ondes. C’est ce débat que nous examinons.
Aller aux théâtres antiques de Rome, les contourner et les traverser
Authors: Monterroso Checa Antonio
Published: February 2014

Cet article s’efforce de restituer, sur la longue durée, pour la ville de Rome, les modalités selon lesquelles les différentes couches de la société urbaine se rendaient au théâtre. Sont d’abord examinés les lieux des représentations théâtrales, principalement les cirques, et leur signification topographique, puis la construction de bâtiments pérennes avec le concept nouveau introduit par le complexe de Pompée au Champ de Mars. Les rapports entre le théâtre et les cérémoniaux, ou encore la viabilité sacrée de Rome à proximité et à l’intérieur des édifices, sont enfin abordés. Il s’agit ainsi d’esquisser les similitudes et les différences avec les usages, l’insertion dans le tissu urbain et la signification des théâtres modernes.
Aller au théâtre dans les villes romaines
Authors: Letellier Éloïse
Published: February 2014

Marqueurs d’urbanité dans tout le monde romain, les théâtres offraient un lieu de rassemblement privilégié au sein des villes, dès la fin de la République puis sous l’Empire. Ils abritaient spectacles et divertissements, mais constituaient aussi le cadre monumental de temps importants de la vie civique, religieuse et politique. « Aller au théâtre » dans les villes romaines relevait à la fois de pratiques quotidiennes et de mises en scène urbaines plus exceptionnelles. Une étude conjointe des sources textuelles et archéologiques disponibles permet d’envisager plus précisément ces pratiques, où se révèle un jeu complexe entre volonté de rassemblement de toute la population et mise en valeur de distinctions sociales. L’article propose ainsi de confronter textes normatifs et choix de construction opérés pour la gestion des accès au théâtre dans certains cas propices à l’observation archéologique.
Transport et divertissement dans les villes anglaises à travers le long XVIII e siècle
Authors: Borsay Peter , Salnot Paula
Published: February 2014

Au long XVIII e siècle, les îles britanniques virent une urbanisation rapide. La croissance démographique et commerciale mit une pression de plus en plus importante sur l’infrastructure des villes, dont les rues remontaient souvent au Moyen Âge. Une partie de cette pression vint d’une hausse de la circulation liée aux loisirs, avec les visiteurs des nouveaux équipements de loisirs – salles d’assemblée ou de concert, théâtres, promenades et boutiques de luxe – qui avaient vu le jour dans le cadre d’une renaissance culturelle dans de nombreuses villes. Cet article explore la hausse de la circulation urbaine liée aux loisirs, ses enjeux, ainsi que les stratégies mises en œuvre par les villes pour faire face à ces difficultés. Pour un voyageur à la mode, se déplacer en ville pouvait être une affaire ennuyeuse et dangereuse, étant donné le risque de se faire bloquer dans la circulation voire de se faire voler. Or des réaménagements de la voirie, la rénovation des équipements de loisirs pour en faciliter l’accès, ou l’amélioration des services de police urbaine, mitigèrent un grand nombre de ces problèmes et montrèrent la capacité du système urbain à répondre avec succès aux complications liées à l’accélération du développement urbain.
Circulation et théâtromanie au temps des embellissements
Authors: Loir Christophe
Published: February 2014

L’objectif de l’article est de montrer comment, dans le contexte de la théâtromanie de la seconde moitié du XVIII e siècle, les projets de salles de spectacle et d’embellissement des villes ont permis de développer de nouvelles solutions architecturales, urbanistiques et réglementaires pour faire face aux problèmes de mobilité posés par l’arrivée et le départ de centaines de spectateurs à pied et en voiture. L’étude de cas choisie est celle des projets de théâtre pour Bruxelles entre 1785 et 1792 analysés selon une approche multiscalaire (édifice, quartier, ville).
Penser la politique dans les villes allemandes à la fin du Moyen Âge
Authors: Adrian Dominique
Published: February 2014

Les villes allemandes de la fin du Moyen Âge ne sont pas marquées par la culture universitaire aristotélicienne comme le sont leurs consœurs italiennes. Comment, dès lors, peuvent-elles penser leur organisation politique, elles qui ont souvent l’occasion de refondre leurs institutions pour les adapter à l’évolution des équilibres sociaux ? Les quelques poèmes didactiques conservés sont souvent trop généralistes ou moralisateurs pour donner à apercevoir une telle réflexion ; vers 1400, deux vastes traités septentrionaux tentent de fonder en droit non seulement la position juridique de la ville, mais aussi les principes de fonctionnement de son organisation politique, en assimilant pour l’un d’eux le droit de sa ville au droit romain. Pour les villes méridionales, de tels textes n’existent pas : c’est alors dans une variété de sources qu’on doit aller chercher les traces de l’importance du politique et des réflexions qu’il suscite, dans un monde urbain où les défis de la vie en commun imposent une véritable créativité institutionnelle.
Criminal Responsibility of Legal Persons in Spanish Law
Authors: de La Cuesta José Luis
Published: February 2014

En 1983, la réforme urgente et partielle de l’ancien Code pénal a maintenu la règle societas delinquere non potest, généralement appliquée par l’Espagne, et conçue pour éliminer certaines lacunes de punissabilité, notamment concernant la règle appelée delicta specialis, c’est-à-dire, pour les délits dans lesquels seule la personne morale remplie les éléments de l’incrimination. La même approche a été suivie par le nouveau Code pénal espagnol (1995). Néanmoins, la loi organique 5/2010 a définitivement enterré cet ancien paradigme en Espagne, consacrant la possibilité d’une responsabilité pénale spéciale des personnes morales, se limitant à une liste strictement définie (numerus clausus).
Protestants et juifs français : des précurseurs de la laïcité
Authors: Cabanel Patrick
Published: February 2014

Le processus de laïcisation à la française, au XIX e siècle, a fait un perdant, le catholicisme, et des gagnants, les minorités protestante et juive. Celles-ci s’accommodaient pourtant fort bien, dans un premier temps, du système des « cultes reconnus » qui leur offrait protection et même réparation de la part d’un État qui avait cessé d’être catholique. Mais la radicalisation ultramontaine de l’Église, le vote de la loi Falloux (1850), et aussi les progrès du libéralisme religieux dans leurs rangs, ont conduit protestants et juifs à souhaiter la laïcité de l’école et plus largement de l’espace public et de la culture de la nation. Ils ont donné, les premiers surtout, à la laïcité du dernier tiers du siècle un certain nombre de penseurs et de dirigeants de premier plan. Ils ont nourri le rêve, bientôt déçu, d’instaurer en France une forme de République kantienne, qui aurait uni religion laïque et laïcité religieuse.
La difficile laïcisation du serment judiciaire
Authors: Lalouette Jacqueline
Published: February 2014

Au XIX e siècle, et au-delà, le sacré qui imprègne les rituels judiciaires, se doubla d’une empreinte religieuse, exprimée par la référence à Dieu, explicite ou implicite, dans le serment prêté par les jurés et les témoins, et par la présence de crucifix dans les tribunaux. Le serment posa divers problèmes ; les quakers et les anabaptistes ne voulaient pas jurer ; les juifs refusaient le rite judaïque que les pouvoirs publics leur imposaient ; les libres penseurs exigeaient le retrait du nom de Dieu de la formule du serment prêté aux assises. La Cour de cassation donna satisfaction aux protestants dissidents et aux juifs. Mais, durant la Troisième République, par crainte de l’athéisme, le Législateur, dont le concours était nécessaire pour modifier les Codes, se refusa à laïciser la formule du serment, qui ne devint laïque qu’en 1972. Quant aux crucifix, ils furent retirés par voie réglementaire en 1904.
La vertu et la terreur : Le Moine
Authors: Brooks Peter
Published: February 2014

Le Moine (1796) de M.G. Lewis, l’un des plus intelligents des romans gothiques, est publié à la fin des Lumières, lors de la Révolution et de la réaction qu’elle engendre. Il met en scène un monde où la raison et le sentiment traditionnel du Sacré sont en perte de vitesse. Ce n’est pas un nouveau système de croyances qui prend leur place mais plutôt une peur primitive des forces démoniaques. Dans le roman de Lewis, ces forces dérivent de l’érotique, normalement sujette au refoulement, et se situent vraisemblablement dans l’inconscient. Le roman met en action l’arrivée sur terre de forces qui excèdent tout contrôle rationnel. Et au point culminant du roman, elles agissent sous terre, dans une crypte.
Clément Ader, entrepreneur d'invention
Authors: Carnino Guillaume
Published: February 2014

Clément Ader est l’inventeur de l’avion (le véhicule et le mot). Or, la vie du « père de l’aviation » se trouve affublée d’une dimension mythologique, ayant invariablement pour but de révéler la gloire éternelle (et en son temps méconnue) du génial inventeur. En réalité, Ader est loin d’avoir été un martyr, et il a même amassé une considérable fortune au cours de sa brillante carrière d’entrepreneur d’invention. À partir de l’étude des archives du fonds Ader au CNAM, cet article retrace la façon dont la légende noire de l’inventeur s’est progressivement instaurée, au détriment de la réalité historique.
Crystallographic Properties of Aluminum-Doped Barium Zirconium Titanate Thin Films by Sol Gel Process
Authors: Andika Rachmat , Hikam Muhammad
Published: February 2014

We studied the crystallographic of Barium Zirconium Titanate thin films with Aluminum doped (BZAT). These films were prepared by sol-gel process and followed by spin coating. The sintering temperature is taken at 800°C and 900°C. We found that the crystallographic system of BZAT thin films have tetragonal structure with the lattice parameter slightly changed by various Aluminum partial substitution. When 0.01 Al moles added, the grain size of the films is 29.42 nm at 800°C. The sintering temperature 900°C increased the grain size into 50.95 nm. We also calculated the spontaneous polarization theoretically and we found the optimum value of BZT thin film with 0.01 mole Al heated at 800°C, is 0.143 C/m2. This way, we could predict that the film has ferroelectric phase.
Lead-Free Oxide Thin Films for Gas Detection
Authors: Fasquelle Didier , Députier S. , Mascot M. , Uschanoff N. , Bouquet V. , Demange V. , Guilloux-Viry M. , Carru J.C.
Published: February 2014

In view to develop gas sensors, a first generation of lead-free thin films was deposited by different techniques on commercial Si and Al2O3 substrates. During our research project, the correlation between the micro structure of films, the structure of the embedded sensors and the applied temperature range, is being studied. In the first year, doped and undoped BaTiO3, KNbO3 and ZnO thin films have been deposited by sol-gel and PLD techniques. BT and BST films have shown a polycrystalline structure with very fine and regular grains, while disoriented grains with an average size ranging from 50 to 200 nm were observed on the KNbO3 film surface, and ZnO films exhibited a columnar growth. All films were characterized and finally embedded to make semiconductor gas sensors which have been tested under different gases. In this first generation of sensors, ZnO sensors have shown encouraging preliminary results under CO and H2S gases.
Keywords : thin films, lead-free oxide, sensor, gas.
Modifications of Multi-Walled Carbon Nanotubes on Zinc Oxide Nanostructures for Carbon Monoxide (CO) Gas Sensitive Layer
Authors: Iqbal Muhammad , Yuliarto Brian , Nugraha Nugraha
Published: February 2014

A novel functional material has been synthesized by modification of multi-walled carbon nanotubes (MWNTs) with nanostructured zinc oxide (ZnO). Multi-walled carbon nanotubes have unique electronic and photonic properties, as well as nanostructured zinc oxide [. Both have advantages when combined as to provide a material with extremely high surface area-to-volume ratio, which is required for the sensor structure. So far, CNT-based gas sensors have been investigated for the detection of H2, N2, NO2, and NH3 [. In this study, modification of multi-walled carbon nanotubes with nanostructured zinc oxide is conducted by simple screen printing and ultrasonic spray pyrolysis (USP) methods, which consists of the fabrication of MWNTs paste, the formation of ZnO sol, and calcination. The deposited thin films are then characterized using several characterization techniques, such as X-ray diffraction and SEM. The performance testing of the sample as a CO gas sensitive layer has also been investigated and the measurement results on 100 ppm CO gas exposure at 250°C showed the sample had a sensitivity of 85%, response time of 5 minutes and recovery time of 20 minutes.
Synthesis of Mesoporous Silica from Tetraethylorthosilicate by Using Sodium Ricinoleic as a Template and 3-Aminopropyltrimethoxysilane as Co-Structure Directing Agent with Volume Variation of Hydrochloric Acid 0.1 M
Authors: Andriayani Andriayani , Sembiring Seri Bima , Aksara Nida , Sofyan Nofrijon
Published: February 2014

Synthesis of mesoporous silica from tetraethylorthosilicate (TEOS) by using sodium ricinoleic as a template and 3-aminopropyltrimethoxysilane (APMS) as a co-structure directing agents (CDSA) in a volume variation of acid addition has been carried out. Preparation of mesoporous silica was conducted in HCl 0.1 M at volume variations of 2 ml, 35 ml, 40 ml and 50 ml. In acid conditions, the amine groups of APMS will protonate, which will then interact electrostatically with the carboxylate groups from ricinoleic acid, while the methoxy groups from APMS will condense with the silanol groups from TEOS to form an end product of mesoporous silica. The reaction products were characterized by using X-ray diffractometer (XRD), Fourier transform infra-red spectrometer (FTIR), surface area analyzer (BET), scanning electron microscope (SEM), and transmission electron microscope (TEM). X-ray diffractograms of the products from all of the acid volume variation additions show broadening peaks indicating amorphous materials as a characteristic of mesoporous materials. Infrared spectra show that all of the products have Si-OH and Si-O-Si groups that are characteristics for mesoporous silica. Imaging results from SEM and TEM show morphology and particle size differences in accordance with the differences in volume variation of acid addition. Adsorption/desorption isotherm by using nitrogen at 77 K of the products from the addition of 2 ml of HCl show an isotherm Type II (adsorption on the surface layer) with irregular pore size distribution, whereas from the addition of 30 ml, 35 ml, 40 ml and 50 ml HCl show an isotherm Type IV with a hysteresis loop that is characteristic for mesoporous materials with a regular pore size distribution.
Optimizing the Nanostructural Characteristics of Chemical Bath Deposition Derived ZnO Nanorods by Post-Hydrothermal Treatments
Authors: Yuwono Akhmad Herman , Sholehah Amalia , Harjanto Sri , Dhaneswara Donanta , Maulidiah Fajrika
Published: February 2014

Zinc oxide (ZnO) is an inorganic semiconductor material which has been widely studied due to its various potential applications. Over the past decades, one-dimensional (1-D) nanostructures such as nanowires and nanorods have stimulated significant scientific interests because of their unique properties in comparison to bulk materials. For the application of dye sensitized solar cell (DSSC), 1-D ZnO nanostructures are more desired than the spherical nanoparticles since the former provides ballistic effect leading to faster electron transfer which in turn can increase the device performance. Motivated by this consideration, in the current study ZnO nanorods were deposited on ITO glass substrate via chemical bath deposition (CBD) process where the seeding solution was prepared at 0°C. In order to increase their crystallinity and optical properties, the as-deposited ZnO nanorods were subjected to post-hydrothermal treatment at 150°C for 3, 6 and 9 hours. The scanning electron microscope (SEM) analysis revealed that the ZnO nanorods were successfully grown as vertically-aligned hexagonal structure, while the X-ray diffraction (XRD) study showed that the intensity of (002) crystal plane is the highest peak for all nanorod samples. The optical study by UV-Vis spectroscopy showed that the absorption edge of the as-deposited sample was slightly red-shifted to visible region after post-hydrothermal treatment. The ZnO nanorods sample derived from post-hydrothermal treatment for 6 hours provided the optimum nanostructural characteristics with an average diameter of 228 nm, crystallite size of 27.97 nm and the band gap energy, Eg, of 3.12 eV.
Synthesis and Characterization of Nanocrystalline TiO2 by Non-Aqueous Sol-Gel in Acidic Condition for Dye-Sensitized Solar Cells
Authors: Muliani Lia , Sunendar Bambang
Published: February 2014

Nanocrystalline TiO2 has been synthesized through non-aqueous sol-gel using acetic acid (HOAc) and hydrochloric acid (HCl) as a catalyst. Titanium isopropoxide (TTIP) as precursor was prepared by reaction between TiCl4 with isopropyl alcohol (IPA) in concentration of 0.3 M. The sol-gel process employed at around 60°C using tert-butanol as solvent and HOAc was added as ligand to stabilize the reaction. Controlled hydrolysis and condensation reactions were achieved through in-taking of water molecules released from the esterification reaction of HOAc with tert-butanol. In this paper, the influence of acidic catalyst was described at the volume ratio of HOAc:HCl are 0:2 ; 1:1 and 2:0. The crystallinity and crystal phase of the samples were characterized by X-ray Diffraction and nanocrystalline TiO2 with anatase phase was resulted. The morphology of the TiO2 powder was analyzed by Scanning Electron Microscopy. Pore size and the BET surface area were determined by Brunauer-Emmett-Teller (BET) analysis. Nanocrystalline TiO2 produced was applied for photoelectrode of dye-sensitized solar cell. The optical properties of the TiO2 photoelectrodes were measured using by UV-Vis Spectrophotometer. The performance of the cell was measured using a solar simulator with light at an intensity of 50 mW/cm2 generated by a xenon lamp. The best efficiency of 0.5% was achieved for active area of 0.48 cm2.
Synthesis of SnO2 Nanostructure Thin Film and its Prospective as Gas Sensors
Authors: Yuliarto Brian , Nugraha Nugraha , Epindonta Bernardus , Aditia Rifai , Iqbal Muhammad
Published: February 2014

This report describes the preparation of gas sensors based on SnO2 semiconductor nanostructure thin films synthesized using chemical bath deposition (CBD) technique. As the rapid demand of the gas sensors based on the semiconductor materials, there have been significant efforts to improve the performance of the semiconductors sensors. SnO2, which has good electrical and mechanical properties, is one of the potential materials to be developed. In the present study, the SnO2, prepared using CBD technique with stannous cloride as precursors, has nanopattern that give much SO2 particles to access into the semiconductor surface. The resulting nanostructure SnO2 thin films have been confirmed by X Ray Diffractions (XRD), Energy Dispersive Spectroscopy (EDS) and Scanning Electronic Micrsocopy (SEM). The as fabricated SnO2 thin films sensors were then characterized as SO2 gas sensors in various concentrations for several different operating temperatures. The sensors have good sensitivity as low as 30 ppm of SO2 gas at the optimum temperature of 2000 C.
Preliminary Observation on Macro Texture of Nb3Sn Low Temperature Superconductor (LTS)
Authors: Pramono Andika Widya
Published: February 2014

The macro texture of Nb3Sn superconductor was observed in order to identify the tendency of crystallographic orientation of such A15 compound. The Nb3Sn samples were prepared through the powder metallurgy process with the composition of 24at%Sn-76at%Nb. The well-blended Nb-Sn powder was consolidated by means of the uni-axial compression method, while the subsequent sintering was performed at T = 700°C for t = 96 hr. The macro texture of the sintered samples was measured using D8 Advance XRD Goniometer and the corresponding results were analyzed in the form of pole figures. Preliminary results indicate that the crystallographic orientations of Nb3Sn for both green compact and sintered samples show the strong textures in {112}-pole figures. The intensity of Nb3Sn textures decreases from green compact sample to sintered sample, probably due to the mechanism of recovery recrystallisation following the Nb-Sn inter-diffusion process during sintering.
Properties of Fe-Mn-C Alloy as Degradable Biomaterials Candidate for Coronary Stent
Authors: Harjanto Sri , Pratesa Yudha , Prasetyo Yudi , Suharno Bambang , Syarif Junaidi , Hakim Fuad
Published: February 2014

The development of biomaterial has reached biodegradable stage. Biodegradable means it can be degraded after certain period of time after implantation and cause no harm for the system. Degradable Biomaterial has the potential to be used as Coronary Stent to minimize the risk from thrombosis issue. Thrombosis is a symptom of body defense where will be a clots blood effect around stent area. The formation of clots blood will disturb a blood flow in artery and it will result a restenosis effect.
Synthesis and Characterization of Silica-Lavender Microencapsulation by Sol Gel-Emulsion Method for Anti Mosquito Textile
Authors: Mulyani Wiwiek Eka , Sunendar Bambang
Published: February 2014

Microencapsulation is a new breakthrough in the field of nanotechnology that can be used for various applications, in particular for the application of controlled release material for functional textiles which were added by certain active substances and gave effects when used such as fragrance and anti mosquito textile. In this research, the synthesis of silica-lavender microencapsulation for anti-mosquito textile had been conducted successfully via sol-gel emulsion process. Sodium silicate solution which was emulsified into the lavender oil as an active ingredient acted as oil phase and ethanol solution acted as water phase. The addition of chitosan as surfactant and polymer for encapsulation with starch as soft template affected the rod-structure formation of nanorod. SEM result showed the morphology of silica-lavender. The rod has the average diameter size of 0.042-0.206 μm. The optimum result of rod-structure was obtained by adding 1% (v/v) of chitosan. FTIR analysis indicated the presence of absorbance peaks at wavenumber of 1411.89, 958.62, and 1078.2 cm-1 respectively for C-H (alkanes), C-H (alkenes) and ester functional groups which indicated the lavender compound in silica-lavender. UV-Vis analysis showed the maximum absorbance at wavelength of lavender at 350 nm. The combination of morphology and chemical properties of silica-lavender modified by chitosan-starch made this material as a candidate material for application in functional textile.
Biocompatibility Improvement of NiTi Orthodontic Wire from Various Coatings
Authors: Setiyorini Yuli , Pintowantoro Sungging
Published: February 2014

NiTi alloy is one of important materials in orthodontics. Shape memory effect of this material ensures the possibility to deliver highly desireable light forces for thooth movement. Unfortunately, NiTi has problem in the high amount content of Ni that can cause allergy or even risk of poisioning in the human body due to Ni ion released. To overcome this problem, several methods of coatings were performed to prevent the releasing of Ni ion. They were Electropolishing Pretreatment combined with Photo Electrocatalytic Oxidation, TiN Pack Cementite, Advanced Oxidation Process and Biomimetic Hidroxyapatite. The objective of this research was to analyze the effect of various coatings to the biocompatibility of orthodontic wire. Biocompatibility of coated NiTi wire was investigated through MTT assay using BHK-21 fibroblast cell in order to analyze the toxicity of each coating method. In addition, the surface roughness was determined using Atomic Force Microscope (AFM). Furthermore, the attachment and spreading of fibroblast cell were observed by Scanning Electron Microscope (SEM). The result was revealed that biomimetic HA coating has the highest cell viability percentage due to its surface morphology.
Building Materials Composition Influence to Sound Transmission Loss (STL) Reduction
Authors: Setyowati Erni , Sadwikasari Anggana Fitri
Published: February 2014

The development of the airport always causes the noise impact to the surrounding environment.1 Housing close to the airport will be annoyed by the aircraft noise, especially if the building is not added by absorber building materials. Housing lay out towards the runways as noise sources is also an aspect that should be considered. This research resulted building models equipped by simple material compositions that had capability in reducing the airport noise optimally. The decrease of the noise level found out from the research is caused by the value of Sound Transmission Loss (STL) of the building materials composition. The models of housing are laid out with a number of specific orientation angles towards the runway and resulted values of the highest noise level reduction.
Structural Characterization of Mullite-Based Ceramic Material from Al2O3 and Silica Xerogel Converted from Sago Waste Ash
Authors: Aripin Haji , Mitsudo Seitaro , Prima Endangsusilowati S. , Sudiana Inyoman Nyoman , Kikuchi Hikamitsu , Sano Saboru , Sabchevski Sliven
Published: February 2014

In this investigation, mullite ceramics were produced by mixing Al2O3 and amorphous silica xerogel (SX) extracted from sago waste ash. The composition was prepared by adding an amount from 0 to 80 mol% of Al2O3 into SX. The samples were dry pressed and sintered in the temperature range between 900°C and 1200°C. Their properties have been characterized on the basis of the experimental data obtained using thermal analysis (DSC/TGA, X-ray diffraction and scanning electron microscopy (SEM). The results show that two major differences become obvious when comparing the samples loaded by the smaller and larger amount of Al2O3. First, cristobalite formation is retarded in the sample loaded by the larger amount of Al2O3. Second, at 1200°C, the observed volume fraction of mullite is higher in the sample loaded by the larger amount of Al2O3. The DSC analysis indicates that the mullite crystallization takes place at 1200°C for 60 mol% Al2O3 loaded SX sample as confirmed by the XRD pattern. It was found that there was not a complete reaction of mulitization for sample sintered up to 1200°C.
Correlation of Normal Incidence Sound Absorption Coefficient (NAC) and Random Incidence Sound Absorption Coefficient (RAC) of Polyester/Ramie Fibre Composite Materials
Authors: Farid Mohammad , Heriyanto Tri
Published: February 2014

The acoustical properties of polyester/ramie fibre composite materials that was applied as a sound absorbing material is discussed in this paper. The aim was to determine the correlation between Normal Incidence Sound Absorption Coefficient (NAC) and Random Incidence Sound Absorption Coefficient (RAC) of the fibre composites. The acoustic measurement with Impedance Tube Kit followed the ASTM 1986 E – 1050 – 98 standard. The portion of the ramie fibre was modified with fibre length varied from 0.25 cm, 1 cm to 1.5 cm but at a constant fibre diameter. A constant volume fraction of fibre 20 % was used.The Beevers method was applied to characterize the fibre’s diameter. Results indicated that the sound absorption performance of the composite fibre can reach as high as 99% at frequency of 1225 Hz at aspect ratio of 42. A correlation between NAC and RAC was presented based on a quantitative result.
A Study on the Structure of Novel Polyurethanes Derived from γ-Valerolactone-Based Diol Precursors
Authors: Chalid Mochamad , Heeres Hans J. , Broekhuis Antonius A.
Published: February 2014

As versatile biomass-based diol precursors, N,N'-1,2-ethanediylbis-(4-hydroxy-pentanamide) (1) and 4-hydroxy-N-(2-hydroxyethyl)-pentanamide (2) are potential monomers to synthesize novel polyurethanes through adding di-isocyanates. This study reported the structural analysis and molecular behavior of polyurethanes obtained from polymerization of the diol precursors with aliphatic and aromatic di-isocyanates (hexamethylene diisocyanate, HDI (3), and phenyl-diisocyanate, PDI (4)) in (N,N-dimethylacetamide (DMA) solvents with triethylamine (TEA) catalysts. 1H-NMR, 13C-NMR and Elemental Analysis confirmed structure of the polyurethanes built from both diols and di-isocyanates and FTIR indicated interaction among polyurethane molecules showed at lower wave numbers such as 2855-2976 cm-1 for hydrogen-bonded NH groups and 1621-1643 cm-1 for hydrogen-bonded C=O groups. Furthermore a study on influence of the inter-and intra-molecular hydrogen bonding on the thermal and mechanical properties of the polyurethanes would be an interesting investigation for the next study.
Grain Growth in Millimeter Wave Sintered Alumina Ceramics
Authors: Mitsudo Seitaro , Inagaki S. , Sudiana Inyoman Nyoman , Kuwayama K.
Published: February 2014

The millimeter wave (MMW) sintering of alumina ceramic had been performed. The results revealed that MMW sintered alumina has higher density than that of conventional method on all sintering temperature. However microstructure evaluation demonstrates that grain growth of MM wave annealed alumina is faster than in conventional annealing. It indicates that MM wave enhanced mass transport and solid state reaction rates during sintering. The empirical observations of microwave enhancements have been broadly known as microwave effect. Even though no satisfactory theory existed to explain the effect but the presence the electromagnetic waves (EMW) during microwave heating is clearly the key. In this paper, microwave effect on grain growth of alumina ceramic is presented. Some effective and unique characteristics of the EMW sintering were also discussed as well.
Synthesis of Highly-Ordered TiO2 through CO2 Supercritical Extraction for Dye-Sensitized Solar Cell Application
Authors: Priyono Bambang , Yuwono Akhmad Herman , Munir B. , Rahman A. , Maulana A. , Abimanyu H.
Published: February 2014

Dye-sensitized solar cell (DSSC) is one of the very promising alternative renewable energy sources to anticipate the diminishing in the fossil fuel reserves in the next few decades and to make use of the abundance of intensive sunlight energy in tropical countries like Indonesia. TiO2 nanoparticles have been used as the photo electrode in DSSC because of its high surface area and allow the adsorption of a large number of dye molecules. In the present study, TiO2 aerogel have been synthesized via sol-gel process with water to inorganic precursor ratio (Rw) of 2.00, followed with subsequent drying by CO2 supercritical extraction (SCE). As comparison, the TiO2 xerogel was also prepared by conventional drying and annealing. Both types of gels were subjected to conventional and multi-step annealing. The resulting nanoparticles in aerogel and xerogel have a band-gap energy of 3.10 and 3.04 eV, respectively. The open circuit voltage (Voc) measurement reveals that the DSSC fabricated with aerogel provided a higher voltage (21,40 mV) than xerogel (1,10 mV).
Preparation of the Edible Biocomposite Film Gelatin/Bacterial Cellulose Microcrystal (BCMC): Variation of Matrix Concentration, Filler, and Sonication Time
Authors: Hermansyah Heri , Carissa Rena , Anisa Fitri , Septa Mondya Purna , Utami Tania Surya , Arbianti Rita
Published: February 2014

Several biodegradable polymers have been explored to develop biodegradable edible films in order to reduce the use of conventional plastics. In this study, edible biocomposite film is made from gelatin filled with Bacterial Cellulose Microcrystal (BCMC). BCMC is produced from nata de coco paste, which is hydrolyzed with cellulase enzyme. In making biocomposite, gelatin matrix is first dissolved in distilled water and then mixed with BCMC filler solution in ultrasonic bath. The solution resulted is then casted and dried in room temperature. The addition of BCMC is proven to improve physical properties, mechanical, and thermal properties of the resulting material. BCMC distribution of SEM showed increasing the tensile strength test results, DSC, and WVTR. When the BCMC concentration was varied from 1-4 wt% of the gelatin mass, tensile strength and glass transition temperature (Tg) increased from 37.07 MPa to 74.04 MPa and 27.520°C to 39.60°C, respectively. Water Vapour Transmission Rate (WVTR) decreased from 37.77 gr.m-2.h-1 to 19.73 gr.m-2.h-1. Tensile test and DSC results also increased when varying the sonication time from 3-6 minutes, from 48.57 MPa to 57.23 MPa and 25.890°C to 37.290°C. WVTR decreased from 36.09 gr.m-2.h-1 to 20.54 gr.m-2.h-1.
Atomic Layer Deposition of Inverse Opals for Solar Cell Applications
Authors: Karuturi Siva Krishna , Liu Li Jun , Su Liap Tat , Niu Wen Bin , Tok Alfred Ling Yoong
Published: February 2014

Atomic layer deposition (ALD) technique shows superior application in the fabrication of TiO2 inverse opals (IO), compared with conventional infiltration methods. In the present report, TiO2 IO structures were infiltrated by ALD method in a continuous-flow and internally developed stop-flow process, respectively. The corresponding optical and optoelectrical properties of TiO2 IO structures were investigated. The prepared uniform IO structure of 288 nm was used as a photoanode for dye-sensitized solar cells. An efficiency of 2.22% was achieved, which was much higher than that of prepared by conventional solution-infiltration method. It is indicated that ALD method is an effective approach for fabricating TiO2 IO photoanode.
Characteristics of Environmental Friendly Labeled Plastic Shopping Bags in Indonesia
Authors: Cornelia Melanie , Syarief Rizal , Effendi Hefni , Nurtama Budi
Published: February 2014

Plastics are synthetic polymers, made from petroleum and its derivatives which are non biodegradable. Today, more people used plastic bags to support their activities ,which caused the supply of plastic shopping bags to increase in large number. Plastic bags, eventually, are usually used as garbage which would cause negative impact on the environment. Environmental friendly plastic bags are made from renewable raw materials, such as starch from cassava, corn or others. There are the ones entirely starch based such as Enviplast (biodegradable); the ones with partial mixture of starch with plastic ores such as Ecoplas (biodegradable), the ones plastic ores are formulated with additives Oxium (oxodegradble), and conventional made from plastic ores only. Distinguishing characteristics of samples plastic shopping bags which were taken from domestic and abroad supermarkets can be seen from the result of FTIR, SEM, and AAS analysis along with burial in soil. Density of domestic plastic bag (1.119 g/cm3 ) are 49.55% smaller than samples abroad 2.258 g/cm3 .This means that in the country, a space to hold trash bags in the same weight needed almost 2x larger. Another discovery are some plastic shopping bags are labeled eco-friendly ,but had conventional plastic characteristisc .
SKD 61 Material Surface Treatment with Electric Discharge Machining Using Cu, CuCr & Graphite Electrodes and Dielectric Fluid Jatrophacurcas
Authors: Triyono Triyono , Priadi Dedi , Siradj Eddy S. , Winarto Winarto
Published: February 2014

The emergence of white layer in each process of Electric Discharge Machining (EDM) becomes the focus of attention of the experts. It is harder than the base metal would be advantageous to withstand friction engine components, such as the plastic molding industry. From various studies it has been reported that the increase in the value of hardness of white layer either due to migration of the electrode material and dielectric fluid to the white layer. This paper discusses the influence of electrodes Cu, CuCr and graphite as well as jatrophacurcas dielectric fluid to the surface of the material SKD 61, microhardness of the white layer, Tool Wear Rate (TWR) of Material Removal Rate (MRR), Surface roughness (Ra) and the microstructure. Initial studies conducted are the transesterification and characterization of jatrophacurcas to determine the dielectric strength and the content of metal elements. Furthermore, the EDM testing is done to dies steel of SKD 61 using the electrodes of Cu, CuCr and Graphite. The use of jatrophacurcas yield the best MRR when using Graphite electrodes followed Cu last CuCr. While the smallest TWR produced by Cu electrode, CuCr and then the highest is Graphite. The relative wear which is the ratio TWR with MRR, for the three types of electrodes is always great at a small current then decreases and then tends to be stable with the increase of electric current. Jatrophacurcas for the three types of electrodes provide higher TWR than kerosene. This means that migration of materials is beneficial because larger material, but in terms of the geometric accuracy of the product can lead to decreasing of dimensional tolerances. Vickers hardness values of white layer is achieved by CuCr electrodes, Graphite lowest. Microstructural observation results of EDM white layer using graphite electrodes produce a more uniform thickness than the white layer using Cu and CuCr electrodes. The conclusion of this study that jatrophacurcas can be used as a dielectric fluid in EDM process, because electrode wear during EDM process is relatively high compared with kerosene that is mean more profitable in the surface treatment process of dies steel of SKD 61.
Optimization of Multiple Performance Characteristics in the Wire EDM Process of AISI D2 Tool Steel Using Taguchi and Fuzzy Logic
Authors: Soepangkat Bobby Oedy Pramoedyo , Pramujati Bambang , Lusi Nuraini
Published: February 2014

In this study, the optimization of material removal rate (MRR) and surface roughness (SR) simultaneously in a WEDM process by using Taguchi method with fuzzy logic has been applied. The Wire EDM process parameters (flushing pressure, on time, open voltage, off time and servo voltage) were optimized with considerations of multiple performance characteristics, i.e., MRR and SR. Based on the Taguchi method, an L18 mixed-orthogonal array table was chosen for the experiments. Fuzzy reasoning of the multiple performance characteristics has been developed based on fuzzy logic, which then converted into a fuzzy reasoning grade or FRG. As a result, the optimization of complicated multiple performance characteristics was transformed into the optimization of single response performance index. Experimental results have shown that machining performance characteristics of Wire EDM process can be improved effectively through the combination of Taguchi method and fuzzy logic.
Characterization of Al-7Si-Mg-Cu Turbine Impeller Produced by Investment Casting
Authors: Syahid Muhammad , Sofyan Bondan Tiara , Basuki Singgih G. , Adam Bayu
Published: February 2014

Application of a light-weight material, such as an aluminum alloy, on a turbine impeller can enhance the efficiency of an Organic Rankine Cycle power plant that operates at temperatures below 150 °C. The density of an aluminum alloy only one-third that of steel. However, increased strength of aluminum alloys is needed for turbine impeller qualification. Investment casting was chosen to produce radial inflow turbine impeller due to their complex geometry and precision. It can replace machining process, which is time-consuming and less efficient because of material removal. This study describes the investment casting process used to produce a radial inflow impeller turbine. The study also identifies defects, microstructures and properties of radial inflow turbine impeller. The turbine impeller were produced from Al-7Si-4Mg alloy with 0.38, 3.82, and 6.0 wt. % Cu. Visual examination showed that the turbine impeller was free of macro defects and misruns. Microstructures were characterized by Optical Microscopy and SEM. The structures consisted of α-Al, Si eutectic, AlMgSi, AlMgFeSi (Chinese script) and CuAl2. The higher hardness value of 54HRB was affected by Cu content due to the good mechanical properties of fasa CuAl2.
Deformation Behaviour of Silicon Carbide Reinforced Al-7Si Composite after Balistic Impacts
Authors: Sofyan Bondan Tiara , Rahmalina Dwi , Suharno Bambang , Siradj Eddy S.
Published: February 2014

The deformation after ballistic impact loading of silicon carbide reinforced aluminium alloy composite is investigated in this research. The composite consists of 10 % volume fraction of silicon carbide particulate in a matrix of Al-7Si-Mg-Zn alloy and were produced through the squeeze casting process with a pressure of 1 MPa at semi-solid melting temperatures of 590-610 °C. The mechanical property of the composite was examined with hardness test. The ballistic tests were performed with two types of projectiles, 9 mm and 5.56 mm calibre of projectiles. Furthermore the deformed surfaces were studied with optical microscopy. During ballistic testing, the 9 mm projectile did not pierce the composite plate although the test resulted in significant cracks on the backside of the plate. The cross section observation of the plate showed ductile deformation in the matrix and silicon carbide particulates give significant rule in withstanding the penetration of the projectile. By contrast, the 5.56 mm projectile pierced through the composite and caused a brittle fracture of the matrix.
Mechanical Properties and Microstructure of Welded Dissimilar Metals Using Buttering & Non-Buttering Layer
Authors: Winarto Winarto , Anis Muhammad , Hertanto Teguh Puji
Published: February 2014

Joining of dissimilar metals is to compose different properties of metals in order to minimize material costs and at the same time to maximize the performance of the equipment and machinery. There are a lot of methods of joining of dissimilar metals. However, the fusion welding is mostly used in a wide range of industries. This research is carried out for the process of dissimilar welding between carbon steel plates of ASTM A516-70 and austenitic stainless steel plates ASTM A214-316L by using gas metal arc welding (GMAW). Welding design used is a V-groove by using the buttering process and without buttering (non-buttering) process. Types of filler metals used are ER309L and ER316L-Si. The weldment is then tested by using destructive test (DT) and non-destructive test (NDT). Weldment is also characterized by using X-Ray Diffraction (XRD). The results show that the mechanical properties of weldment with buttering process are better compared with the weldment with a non-buttering process. The macro and microstructure of weldment with buttering process revealed finer grained and homogeneous structures compared with the one by using a non-buttering process. Moreover, welds characterization by using XRD show that the precipitation of chromium carbide on HAZ of weldment with buttering process is lower than that of weldment with a non-buttering process.
Preparation of Uranium Nitride from Uranium Metal through by Hydriding and Nitriding Process
Authors: Suwarno Hadi
Published: February 2014

The RERTR Program (Reduced Enrichment in Research and Test Reactors) is an attempt to utilize uranium fuel enriched below 20% for nuclear research reactors. Since the program was launched by the United States in 1978, the International Atomic Energy Agency (IAEA) has recommended that UxSiy alloys, particularly U3Si2 and U3Si compounds, be used to fuel nuclear research reactors with uranium loading rate up to 4.8 gU/cm3. Unfortunately, there are difficulties in reprocessing U3Si2 and U3Si compounds due to the Si content. To overcome this problem, the IAEA initiated international cooperation to find the best solution in the development of new nuclear fuels to substitute the UxSiy alloys. In order to synthesize nuclear fuel containing high loading of uranium, research in developing uranium nitride (UN) from uranium metal has been conducted by reacting the massive uranium metal with hydrogen gas at a temperature of 573 K followed by dehydriding at a temperature of 773 K under vacuum pressure and nitriding at a temperature of 1073 K by introducing nitrogen gas in the reaction chamber. The X-ray diffraction analysis results showed that the hydriding process caused the uranium metal to turn into a stable compound, UH3, which was identified by the changes of the massive shapes into fine metal powders. Dehydriding process at a temperature of 773 K caused the UH3 compound to decompose into U metal powders, and when the metal powders were reacted with N2 gas at 1073 K a stable phase identified as UN was formed. The results showed that it is possible to produce UN powders by hydriding, dehydriding, and nitriding process, although special handling of UH3 and UN powders is required due to their pyrophoric nature.
Hydrogen Absorpsivity-Desorbsivity of Mg Doped by Ni, Cu, Al Produced by Mechanical Alloying
Authors: Widyastuti Widyastuti , Febrian Budi P. , Sutarsis Sutarsis
Published: February 2014

Mg, in the form of MgH2, is one kinds of materials widely used as hydrogen storage materials. Absorption and desorption properties of hydrogen which comes from metal hydride depend on materials itself, addition of elements, as well as manufacturing method. In this research, Mg as hydrogen storage were prepared by mechanical alloying with Ni, Cu, and Al as element addition and variation milling time for 10, 20 and 30 hours. Some morphological analyses (XRD, SEM) were done to observe phase transformation. Absorption and desorption properties characterization were employed by DSC and hydrogenation tests. The improvement in milling time decreased particle size, therefore enhanced wt% of absorbed hydrogen and decrease onset desorption temperature. However, the excessive of agglomeration and cold welding on mechanical alloying process resulted in bigger particle size. Alloying elements, Al and Cu, served as catalyst, while Ni acted as alloying which reacted with hydrogen. Mg10wt%Al with 20 hours milling time at hydrogenation temperature 250°C, 3 atm pressure, and 1 hour holding time resulted in the highest weight percent of H2 (0.38%wt). However, Mg10wt%Al with 30 hours milling time had the lowest onset temperature, 341.49°C
Study about Surface Hardening on Local Disc Brakes with Direct Current Plasma Nitrocarburizing Apparatus
Authors: Sudjadi Usman
Published: February 2014

Surface hardening on local disc brakes with DC-plasma nitrocarburizing apparatus has been carried out. Local disc brake was nitrocarburized at temperatures of 700 °C, 800°C, and 900°C for 3 hours, respectively. The results show that the hardness of sample of local disc brake before nitrocarburization was 167.86 Kgf/mm2, after the sample was nitrocarburized at temperature 900 °C for 3 hours, the hardness increased up to 649.38 Kgf/mm2. Matrixes on the base material were austenite, ferrite, and perlite.