Thermal shock resistance of ceramic fibre composites characterized by non-destructive methods

Alumina based ceramic fibres and alumina based ceramic were used to produce composite material. Behaviour of composite ceramics after thermal shock treatments was investigated. Thermal shock of the samples was evaluated using water quench test. Surface deterioration level of samples was monitored by image analysis before and after a number of quenching cycles. Ultrasonic measurements were done on samples after quench tests. Dynamic Young modulus of elasticity and strength degradation were calculated using measured values of ultrasonic velocities. Strengths deterioration was calculated using the non-destructive measurements and correlated to degradation of surface area and number of quenches. The addition of small amount of ceramic fibres improves the strengths and diminishes the loss of mechanical properties of samples during thermal shock experiments

Lasersko čišćenje tekstilnih eksponata sa korodiranim metalnim nitima - optimzacije parametara procesa

This paper presents the results of the laser cleaning effects on textile samples with corroded metallic threads. In many museum collections, there are textile exhibits like uniforms, national costumes, flags and home textile, embroidered with metallic threads. Corrosion of metal threads is one of the most common problems that damage embroidered items. In the practice, the application of conventional cleaning methods rarely gives the expected results, and the implementation of laser technology was the next step for corrosion products cleaning. The Nd:YAG laser was used to clean the corrosion of embroidered items from a museum study collection. The effects on the laser irradiated zones were investigated by optical and SEM microscopy and the EDX analysis. The laser irradiation process parameters of the metal threads corrosionU radu su prikazani rezultati čišćenja korozije na tekstilnim eksponatima sa metalnim nitima pomoću lasera. U mnogim muzejskim zbirkama nalaze se eksponati kao što su uniforme, narodne nošnje, zastave i kućni tekstil, ukrašeni vezom metalnim nitima. Korozija metalnih niti je jedan od najvećih problema, koji oštećuje vezene eksponate. U praksi, veoma često, klasične metode ne daju očekivane rezultate i primena lasera je sledeći korak čišćenja korozionih produkata. Nd- YAG laser je korišćen za čišćenje korozije vezenih eksponata iz muzejske, studijske zbirke. Efekti u zonama ozračenim laserom su ispitivani optičkim mikroskopom, SEMom i EDX analizom. Određeni su izabrani parametri za uspešno i bezbedno čišćenje korozije na metalnim nitima.В этой статье приведены результаты очистки коррозии на экспонатах из текстиля с металлическими нитями с помощью лазера. Во многих музейных коллекциях представлены экспонаты, такие как формы, народные костюмы, флаги и домашний текстиль, вышитые металлической нитью. Коррозия металлических нитей является одной из самых больших проблем, которая повреждает вышитые экспонаты. На практике, очень часто, классические методы не дают ожидаемых результатов и применение лазера является следующим шагом очистки следов коррозии. Nd-YAG лазер используется для очистки коррозии вышитых экспонатов из музейных исследовательских коллекций. Эффекты в областях облученных лазером были исследованы с помощью оптического микроскопа, SEM и EDX анализом. Некоторые параметры определяются и выбираются так, чтобы успешно и безопасно очистить металлические нити от коррозии.Dans ce papier on a présenté les résultats du nettoyage de corrosion chez les objets exposés en textile aux fils métalliques réalisé au moyen du laser. Dans plusieurs collections de musée on trouve les objets tels que uniformes, costumes nationaux, drapeaux et textile de maison qui sont ornés de broderie faite en fils de métal. La corrosion des fils en métal est un des plus grands problèmes car elle endommage les objets exposés brodés. En pratique les méthodes classiques ne donnent pas souvent les résultats espérés et l’utilisation du laser est le pas suivant dans le nettoyage des produits de corrosion. Le laser Nd-YAG a été utilisé pour le nettoyage de corrosion sur les objets brodés appartenant à la collection d’étude de musée. Dans les zones irradiées par laser les effets ont été étudiés au moyen du microscope optique et en utilisant les analyses SEM et EDX. On a déterminé les paramètres choisis pour le nettoyage en sécurité et avec succès de la corrosion chez les fils en métal

Comparation of mechanical behaviour of SiC sintered specimen to analysis of surface defects

This research examined SiC sintered specimens with high hardness and strength. This material is used to protect of projectile impact for military purposes. The testing procedure consists of structure examination obtained using XRD analysis, surface examination by SEM analysis and optical microscopy, examination of mechanical properties and density determination. Analysis confirmed surface irregularities characterized using image analysis. The sample is subjected to bending. Finite element modeling was used to simulate the behavior of sample subjected to bending in presence of critical damage on surface. It is confirmed that there is correlation between the largest irregularities determined on surface and measured strength of sample. Simulations show the significance of damage size. The size of damage on surface is considered to be the critical parameter for quality determination.Program and the book of abstracts available at: [https://dais.sanu.ac.rs/handle/123456789/175

Experimental archaeology – multidisciplinary research into Pločnik site

Multidisciplinary research of traditional pottery production includes three primary areas: heritology, materials technology and experimental archeology, which are methodologically supported by geological and physical-chemical analysis, and methodological apparatus of anthropology and ethnology. Definition of intangible heritage in the field of traditional ceramics manufacturing, in accordance with the Convention on the Protection of Intangible Cultural Heritage (UNESCO), refers to the identification, investigation and documentation of authentic production technology of ceramics, and revitalization of intangible cultural heritage through education and the transfer of traditional techniques. In this paper the planned research phases of the Neolithic pottery Vinča (B), Vinča-Tordos II, from the location near Prokuplje are presented. The main aim of this research is to protect the traditional production of pottery technology as an intangible cultural asset

Non-destructive characterisation and classification of ceramic artefacts using pEDXRF and statistical pattern recognition

Background: Portable energy dispersive X-ray fluorescence (pEDXRF) spectrometry analysis was applied for the characterisation of archaeological ceramic findings from three Neolithic sites in Serbia. Two dimension reduction techniques, principal component analysis (PCA) and scattering matrices-based dimension reduction were used to examine the possible classification of those findings, and to extract the most discriminant features. Results: A decision-making procedure is proposed, whose goal is to classify unknown ceramic findings based on their elemental compositions derived by pEDXRF spectrometry. As a major part of decision-making procedure, the possibilities of two dimension reduction methods were tested. Scattering matrices-based dimension reduction was found to be the more efficient method for the purpose. Linear classifiers designed based on the desired output allowed for 7 of 8 unknown samples from the test set to be correctly classified. Conclusions: Based on the results, the conclusion is that despite the constraints typical of the applied analytical technique, the elemental composition can be considered as viable information in provenience studies. With a fully-developed procedure, ceramic artefacts can be classified based on their elemental composition and well-known provenance

The role of experimental research on ceramics in the identification of intangible cultural heritage

Pottery is the most durable artifact in archeology that could be used to determine the technological level, as well as helpful identification of ancient people's life. Existence of the technological method of ancient man that evolved in response to their environment is the subject of research in experimental archeology and evidence of existence of the intangible cultural heritage. Studying the neolith technology and possible interaction with later cultures includes multidisciplinary study. Initial research is aimed to classification, structure and artifacts studies that could lead to assumptions aboutthe preparation technique of pottery from archaeological site of Pločnik

Essential oil of Salvia officinalis L. from Serbia and Montenegro

The content and composition of essential oil in the leaves and flowers of 11 populations of Salvia officinalis L. native in Montenegro (nine populations) and Serbia (two populations) have been studied. The yield of oils was generally higher in the leaves than the flowers. The Serbian populations proved to be the richest in leaf oil (average content 1.66%). Montenegro speciments showed significant interpopulation variation and the yields averaged 1.41% for the leaves and 1.13% for the flowers. The main compounds in the leaves were oxygenated monoterpenes: α-thujone (15.79 ± 4.9%), β-thujone (3.49 ± 1.21%), 1.8-cineol (12.09 ± 3.5%), camphor (11.49 ± 7.69%), borneol (4.17 ± 2.23%) and bornyl acetate (2.19 ± 1.22%). Among the dominant sesquiterpenes were: α-humulene (7.70 ± 3.12%), viridiflorol (13.19 ± 5.17%) and manool (7.67 ± 2.98%). In the flowers, percentages of α-thujone and camphor were significantly lower than in the leaves and averaged 9.97 ± 1.49% and 5.82 ± 5.6%, respectively, whereas the ratios of borneol (6.35 ± 2.47%) and sesquiterpenes, particularly manool (13.48 ± 3.56%), were higher. Great variation was found in the proportions of the major compounds between the populations examined. Copyright © 2002 John Wiley & Sons, Ltd

Surface Modification of Aqueduct Ceramics Induced by Nd:Yag Pulsed Laser Treatment

The main aim of this paper is to present the results of the morphological and chemical changes on the surface of a ceramic sample irradiated by the Nd:YAG laser. The tested sample is a part of an aqueduct tile, originating from the archaeological site of Yazd, Iran. The laser irradiation effects were studied as a function of the number of laser pulses and laser fluences around and over the damage threshold. The obtained modifications were investigated because these are essential in laser cleaning of aqueduct ceramics. The Nd: YAG laser with a wavelength, lambda, of 1064 nm and full width at half maximum (FWHM) pulse, tau, of 150 ps has been used for the surface treatment. The ceramic surface morphology modifications, induced by laser, were characterized by a scanning electron microscope (SEM), while the composition was examined by energy-dispersive (EDX) and X-ray fluorescence (XRF) spectroscopy. The results show that there are significant differences depending on the applied laser fluences and whether the surface is glazed or not

Essential oil of calamintha sylvatica bromf. And calamintha vardarensis Šilic

The essential oil of three populations of Calamintha sylvatica Bromf. native to the mountain region of southwestern Serbia and one population of Calamintha vardarensis Šilic from southern former Yugoslav Republic of Macedonia were studied. The highest oil yields were found in C. vardarensis (1.54%), whereas in C. sylvatica oil yields varied from 0.11% up to 0.94%. In all samples, cis-piperitone oxide was a major compound. The highest percentage was found in the oil of C. vardarensis (65.6%). In C. sylvatica piperitone oxide varied from 48.9–59.2%. In the examined samples, oil composition appeared to vary more according to geographical rather than genetic factors. © 2004, Taylor & Francis Group, LLC. All rights reserved

Essential oil of Salvia officinalis L. from Serbia and Montenegro

The content and composition of essential oil in the leaves and flowers of 11 populations of Salvia officinalis L. native in Montenegro (nine populations) and Serbia (two populations) have been studied. The yield of oils was generally higher in the leaves than the flowers. The Serbian populations proved to be the richest in leaf oil (average content 1.66%). Montenegro speciments showed significant interpopulation variation and the yields averaged 1.41% for the leaves and 1.13% for the flowers. The main compounds in the leaves were oxygenated monoterpenes: α-thujone (15.79 ± 4.9%), β-thujone (3.49 ± 1.21%), 1.8-cineol (12.09 ± 3.5%), camphor (11.49 ± 7.69%), borneol (4.17 ± 2.23%) and bornyl acetate (2.19 ± 1.22%). Among the dominant sesquiterpenes were: α-humulene (7.70 ± 3.12%), viridiflorol (13.19 ± 5.17%) and manool (7.67 ± 2.98%). In the flowers, percentages of α-thujone and camphor were significantly lower than in the leaves and averaged 9.97 ± 1.49% and 5.82 ± 5.6%, respectively, whereas the ratios of borneol (6.35 ± 2.47%) and sesquiterpenes, particularly manool (13.48 ± 3.56%), were higher. Great variation was found in the proportions of the major compounds between the populations examined. Copyright © 2002 John Wiley & Sons, Ltd