Search results for: George S. Polymeris

Items from 1 to 20 out of 41 results

article

Assessing the firing temperature of Uruk pottery in the Middle Euphrates Valley (Syria): Bevelled rim bowls

Jorge Sanjurjo-Sánchez, Juan Luis Montero Fenollós, Victor Barrientos, George S. Polymeris

Microchemical Journal > 2018 > 142 > C > 43-53

In geochemical studies on ancient pottery, different methods have been attempted to assess the firing temperature. One of the most successful methods has involved studying mineral phase transformation sequences produced during firing despite the imprecise results usually obtained. The most commonly used methods assess the mineral composition of samples and thermal analysis. In this work, we used optical...

article

Thermoelectric Properties of Bi‐Doped Mg₂Si_0.6Sn_0.4 Solid Solutions Synthesized by Two‐Step Low Temperature Reaction Combined with Hot Pressing

George S. Polymeris, Nikolaos Vlachos, Elli Symeou, Theodora Kyratsi

physica status solidi (a) > 215 > 17 > n/a - n/a

The goal of this study is to investigate the influence of the amount of Bi doping on the microstructure and thermoelectric properties of the Mg₂Si_0.60Sn_0.4 material studied by X‐ray diffraction, scanning electron microscopy, and thermoelectric measurements. The results of the present study provide strong evidence for the presence of a number of secondary phases with different stoichiometries, including...

article

Determination of trapping parameters in BeO ceramics in both quenched as well as reconstructed thermoluminescence glow curves using various analysis methods

Engin Aşlar, Eren Şahiner, George S. Polymeris, Niyazi Meriç

Applied Radiation and Isotopes > 2017 > 129 > C > 142-151

The trapping parameters of BeO thermoluminescence peaks 2 and 3 (with delocalization temperatures of 192 and 308°C respectively, obtained with heating rate of 1K/s) have been calculated using various analysis techniques, including the peak shape methods, isothermal decay, variable heating rates, the fractional glow technique and de-convolution. However, as BeO has been reported to undergo thermal...

article

Calculation of thermal quenching parameters in BeO ceramics using solely TL measurements

Engin Aşlar, Niyazi Meriç, Eren Şahiner, George Kitis, more

Radiation Measurements > 2017 > 103 > C > 13-25

The decrease of the luminescence efficiency with increasing temperature is known as the thermal quenching effect. Various materials exhibit thermal quenching, among which quartz and AI₂O₃:C stand as the mostly well known. BeO, which is used generally as OSL dosimeter, has been reported to undergo thermal quenching effect; so far in the literature only one thermal quenching parameter was determined...

article

Tunnelling recombination in conventional, post-infrared and post-infrared multi-elevated temperature IRSL signals in microcline K-feldspar

Eren Şahiner, George Kitis, Vasilis Pagonis, Niyazi Meriç, more

Journal of Luminescence > 2017 > 188 > C > 514-523

In this manuscript, we study three different types of infrared stimulated luminescence signals (IRSL) from a microcline K-feldspar. These signals consist of conventional infrared (IR) stimulation measured at elevated temperatures, multi-elevated temperature post-infrared IRSL signals (MET-pIRIR), and post-infrared IRSL (pIRIR) signals. All three types of signals were analysed using analytical expressions...

article

Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

Ebenezer O. Oniya, George S. Polymeris, Nnamdi N. Jibiri, Nestor C. Tsirliganis, more

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions... > 2017 > 400 > C > 1-10

The sensitisation of quartz has attracted much attention since its thorough understanding is important in luminescence studies and dating applications. The present investigation examines the influence of pure thermal activation and predose treatments on the sensitisation of different components of linearly modulated optically stimulated luminescence (LM-OSL) measured at room temperature (RT) thereby...

article

Archaeomagnetic versus luminescence methods: the case of an Early Byzantine ceramic workshop in Thessaloniki, Greece

Elina Aidona, George S. Polymeris, Pierre Camps, Despina Kondopoulou, more

Archaeological and Anthropological Sciences > 2018 > 10 > 4 > 725-741

In this contribution, we present a combined archaeomagnetic and luminescence study of archaeologically dated structures. The investigated area is a ceramic workshop comprising several Early Byzantine kilns. Based on (a) the archaeological–anthropogenic stratigraphy of the site, (b) the structural characteristics of the kilns and (c) the few ceramic findings revealed within their context, the operation...

article

Component resolved bleaching study in natural calcium fluoride using CW-OSL, LM-OSL and residual TL glow curves after bleaching

Vasiliki Angeli, George S. Polymeris, Ioanna K. Sfampa, Nestor C. Tsirliganis, more

Applied Radiation and Isotopes > 2017 > 122 > C > 89-95

Natural calcium fluoride has been commonly used as thermoluminescence (TL) dosimeter due to its high luminescence intensity. The aim of this work includes attempting a correlation between specific TL glow curves after bleaching and components of linearly modulated optically stimulated luminescence (LM-OSL) as well as continuous wave OSL (CW-OSL). A component resolved analysis was applied to both integrated...

article

Thermoluminescence glow curves in preheated feldspar samples: An interpretation based on random defect distributions

George S. Polymeris, Vasilis Pagonis, George Kitis

Radiation Measurements > 2017 > 97 > C > 20-27

Thermoluminescence (TL) glow curves from feldspar samples have been studied extensively in luminescence dating and dosimetry applications. However, the mechanism responsible for their unusual shape and behavior in preheated samples is not well understood. This paper presents new experimental TL glow curves for four types of preheated feldspar samples; an orthoclase, a sanidine and two microclines...

article

Thermally assisted OSL application for equivalent dose estimation; comparison of multiple equivalent dose values as well as saturation levels determined by luminescence and ESR techniques for a sedimentary sample collected from a fault gouge

Eren Şahiner, Niyazi Meriç, George S. Polymeris

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions... > 2017 > 392 > C > 21-30

Equivalent dose estimation (D_e) constitutes the most important part of either trap-charge dating techniques or dosimetry applications. In the present work, multiple, independent equivalent dose estimation approaches were adopted, using both luminescence and ESR techniques; two different minerals were studied, namely quartz as well as feldspathic polymineral samples. The work is divided into three...

article

Similarities and differences between two different types of the thermoluminescence dosimeters belonging to the LiF family

A. M. Sadek, F. Khamis, George S. Polymeris, E. Carinou, more

physica status solidi c > 14 > 1-2 > n/a - n/a

The kinetic parameters of the glow‐peaks of Harshaw – LiF:Mg, Ti (TLD) and Poland – LiF:Mg,Ti (MTS) dosimeters were investigated at different dose levels using the computerized glow‐curve deconvolution (CGCD) algorithm. The results showed that the glow‐curve structure and the kinetic parameters of the MTS – 6 and the TLD dosimeter are identical. In addition, the glow‐curve structure and the kinetic...

article

Technological aspects of Mesopotamian Uruk pottery: estimating firing temperatures using mineralogical methods, thermal analysis and luminescence techniques

Jorge Sanjurjo-Sánchez, Juan Luis Montero Fenollós, George S. Polymeris

Archaeological and Anthropological Sciences > 2018 > 10 > 4 > 849-864

The Middle Uruk phase in Mesopotamia (3600–3500 bc) has been characterised by the massive production of “bevelled rim bowls” (BRBs). They are characterised by their similar shape and volume in Mesopotamia and surroundings. However, their production method has not been studied in detail, including the firing temperature. The determination of the firing temperature of ancient pottery has been attempted...

article

Dose response on the 110°C thermoluminescence peak of un-heated, synthetic Merck quartz

Şule Kaya Keleş, Niyazi Meriç, George S. Polymeris

Physica B: Condensed Matter > 2016 > 493 > C > 17-24

Studies on 110°C TL peak have been carried out using natural quartz from different origins and synthetic quartz produced by different suppliers. The interest in quartz is due to its usage in dating and retrospective dosimetry as a main material; both synthetic and natural types of quartz yield the 110°C TL peak in their glow curve. In most studies to understand the physical mechanism behind the TL...

article

Dating fossil root cast (Black Sea coast, Turkey) using thermoluminescence: Implications for windblown drift of shelf carbonates during MIS 2

George S. Polymeris, George Kitis, Nafiye G. Kiyak, Eleni Theodosoglou, more

Quaternary International > 2016 > 401 > C > 184-193

Rhizoliths are mostly sub-aerially exposed root prints which appear through removal of the rock units that cap them. A horizontal-lying residual of a rhizolith, consisting purely of soft inner core material of white color was recovered 10 km west of Şile, Istanbul, in northwest Turkey within laminated oolithic massive aeolianite. The inner part, consisting purely of calcium carbonate, was dated by...

article

Dosimetric and kinetic characteristics of watch glass sample

Canan Aydaş, Ülkü R. Yüce, Birol Engin, George S. Polymeris

Radiation Measurements > 2016 > 85 > C > 78-87

This paper reports the Electron Spin Resonance (ESR) and Thermoluminescence (TL) dosimetric and kinetic characteristics of commercial watch glass. Both of the ESR and TL response of the watch glass sample yielded linear behavior in the 0.5–135 Gy gamma dose range. ESR dosimetric properties of watch glass sample like dose-rate dependence, signal reproducibility and fading behavior have also been studied...

article

Thermal Stability Study from Room Temperature to 1273 K (1000 °C) in Magnesium Silicide

Eleni-Chrysanthi Stefanaki, Euripides Hatzikraniotis, George Vourlias, Konstantinos Chrissafis, more

Metallurgical and Materials Transactions A > 2016 > 47 > 10 > 5146-5158

Doped magnesium silicide has been identified as a promising and environmentally friendly advanced thermoelectric material in the temperature range between 500 K and 800 K (227 °C and 527 °C). Besides the plethora of magnesium silicide thermoelectric advantages, it is well known for its high sensitivity to oxidation. Oxidation is one of the primary instability mechanisms of degradation of high-temperature...

article

Impact of different mechanical pre-treatment to the EPR signals of human fingernails towards studying dose response and fading subjected to UV exposure or beta irradiation

Eren Şahiner, Niyazi Meriç, George S. Polymeris

Radiation Measurements > 2015 > 82 > C > 40-46

In this study, fingernails were investigated by means of Electron Paramagnetic Resonance (EPR) technique, further exploiting its potential use in the field of retrospective dosimetry. The behavior of the radiation induced signal was investigated under beta irradiation and UV light exposure. Nevertheless, before these aforementioned experiments, the optimum handling procedure was established by studying...

article

Dose response and fading studies on de-proteinated tooth enamel after de-convolution using the sum of general order kinetics and a component for tunnelling recombination

Niyazi Meriç, Ülkü Rabia Yüce, Eren Şahiner, Aristis Damianidis, more

Radiation Measurements > 2015 > 81 > Complete > 257-261

The present study reports on the results of dose response and fading for the case of blue stimulated OSL signals from tooth enamel samples. These samples have been previously subjected to two different de-proteinization procedures, after applying hydrazine and sodium hydroxide. The OSL signal, when quantified based on the conventional way of OSL analysis, namely the use of the initial 5 s of the signal...

article

Thermal assistance in TA – OSL signals of feldspar and polymineral samples; comparison with the case of pure quartz

George S. Polymeris, Eren Şahiner, Niyazi Meriç, George Kitis

Radiation Measurements > 2015 > 81 > Complete > 270-274

Thermally assisted optically stimulated luminescence (TA – OSL) is studied for the cases of polymineral, rich in K-feldspar sample as well as one pure sample of K-feldspar. For both cases, the shape of the TA – OSL signal indicates an initial, fast decaying part which is followed by a flat, very slowly decaying part with intensity much larger than the ordinary background noise signal. Thermal assistance...

article

Temperature lags of luminescence measurements in a commercial luminescence reader

George Kitis, Nafiye G. Kiyak, George S. Polymeris

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions... > 2015 > 359 > C > 60-63

The temperature recorded in thermoluminescence and optically stimulated luminescence equipments is not the temperature of the sample but that of the heating element on which the thermocouple is attached. Depending upon the rate of heating, a temperature difference appears between the samples and the heating element, termed as temperature lag, which could have serious effects on the curve shapes and...

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Search results for: George S. Polymeris

Assessing the firing temperature of Uruk pottery in the Middle Euphrates Valley (Syria): Bevelled rim bowls

Thermoelectric Properties of Bi‐Doped Mg₂Si_0.6Sn_0.4 Solid Solutions Synthesized by Two‐Step Low Temperature Reaction Combined with Hot Pressing

Determination of trapping parameters in BeO ceramics in both quenched as well as reconstructed thermoluminescence glow curves using various analysis methods

Calculation of thermal quenching parameters in BeO ceramics using solely TL measurements

Tunnelling recombination in conventional, post-infrared and post-infrared multi-elevated temperature IRSL signals in microcline K-feldspar

Pure thermal sensitisation and pre-dose effect of OSL in both unfired and annealed quartz samples

Archaeomagnetic versus luminescence methods: the case of an Early Byzantine ceramic workshop in Thessaloniki, Greece

Component resolved bleaching study in natural calcium fluoride using CW-OSL, LM-OSL and residual TL glow curves after bleaching

Thermoluminescence glow curves in preheated feldspar samples: An interpretation based on random defect distributions

Thermally assisted OSL application for equivalent dose estimation; comparison of multiple equivalent dose values as well as saturation levels determined by luminescence and ESR techniques for a sedimentary sample collected from a fault gouge

Similarities and differences between two different types of the thermoluminescence dosimeters belonging to the LiF family

Technological aspects of Mesopotamian Uruk pottery: estimating firing temperatures using mineralogical methods, thermal analysis and luminescence techniques

Dose response on the 110°C thermoluminescence peak of un-heated, synthetic Merck quartz

Dating fossil root cast (Black Sea coast, Turkey) using thermoluminescence: Implications for windblown drift of shelf carbonates during MIS 2

Dosimetric and kinetic characteristics of watch glass sample

Thermal Stability Study from Room Temperature to 1273 K (1000 °C) in Magnesium Silicide

Impact of different mechanical pre-treatment to the EPR signals of human fingernails towards studying dose response and fading subjected to UV exposure or beta irradiation

Dose response and fading studies on de-proteinated tooth enamel after de-convolution using the sum of general order kinetics and a component for tunnelling recombination

Thermal assistance in TA – OSL signals of feldspar and polymineral samples; comparison with the case of pure quartz

Temperature lags of luminescence measurements in a commercial luminescence reader

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