Researcher:
Franci, Gülsu Şimşek

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Gülsu Şimşek

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Franci

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Franci, Gülsu Şimşek

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2018 - 201932020 - 202212

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    An archaeometric assessment study of Seljuk period glazed tiles from Kılıçarslan Square (Konya, Turkey)
    (Springer Nature, 2022) Öztürk, Çetin; Kuşoğlu, İhsan Murat; N/A; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; N/A
    This study presents archaeometric analyses of glazed tiles produced with the cut-mosaic technique to reveal information about the Anatolian Seljuk period’s architecture and ceramic technology. The Persian Seljuk artists also used the same technique. For this purpose, physical, chemical, thermal, mineralogical, microstructural, and molecular analyses were carried out on the tiles from the Seljuk period unearthed in the Kılıçarslan Square excavation in Konya, the capital of the Anatolian Seljuk State from the twelfth-century to the beginning of the fourteenth-century. SEM, XRD, and Heat Microscopy analyses showed that the Seljuk period tiles were not fired at high temperatures like today’s tiles and were probably fired at temperatures below 1100 °C. WD-XRF analyses revealed that the glazes are classified into two categories, one being alkali varying the content of Na2O + K2O between 13 and 16 wt% (PbO between 0.5 and 2 wt%) and the other being lead-alkali type in which PbO content varies between 13 and 15 wt% and alkali content 10–14 wt%. The cobalt content in the blue color is around 0.2 wt%, and copper content in the turquoise-colored samples varies between 2.9 and 4.4 wt% depending on the lightness and darkness of the color (higher amount for tile 1 and tile 3, which are darker than the others). The brown color is obtained by the presence of MnO (3.3 wt%). Raman analysis showed that the difference in sintering temperature caused the color tone difference in Seljuk period tiles, and glazes were formed in the range of 800–1000 °C depending on the Ip values.
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    PXRF data evaluation methodology for on-site analysis of precious artifacts: cobalt used in the blue decoration of qing dynasty overglazed porcelain enameled at customs district (Guangzhou), jingdezhen and zaobanchu (Beijing) workshops
    (MDPI, 2022) Colomban, Philippe; Gironda, Michele; d'Abrigeon, Pauline; Schumacher, Anne-Claire; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A
    In a noninvasive determination, Raman and XRF analyses showed the possibility of identifying specific phases and elements characteristic of the use of recipes and ingredients imported from Europe, according to the information documented in Chinese and European archives. Two sets of objects, supposed to have been produced during the Qing Dynasty (1662-1912) at the Forbidden City ('imperial bowls' of the Baur Foundation, Geneva) and in the customs district of Guangzhou (Musee Ariana, Geneva), were analyzed with pXRF and also for some objects with Raman microspectroscopy also on-site. The heterogeneity of the colored zones, in three spatial directions, requires the development of a new methodology. We focused particular attention on the cobalt used in the colored areas and marks, drawn either on the body layer (standard underglaze) or on the glaze itself (overglaze). Comparison is made with previous data on Chinese and Vietnamese porcelains from the Yuan (1271-1368) and Ming Dynasty (1368-1644) periods. Combined data for objects attributed to Guangzhou from the Kangxi and Yongzheng periods indicates the use of the same raw materials containing cobalt, associated with arsenic, nickel, zinc, copper and bismuth, according to the European sources. Similarity of the glaze composition and impurities promotes the production of the glazed body with the same raw materials as those used at Jingdezhen. A consistent shift in data for Qianlong style items, which are significantly richer in manganese, is compatible with their partial mixing with Asian cobalt. The deliberate selection of conflicting objects-namely, examples belonging to the other places of production or different periods-are well-observed outside the 'Guangzhou' cluster. Some artifacts have anachronistic purity characteristics that support a production after ca. 1850. For instance, two objects on which certain attributions had been made concerning the stylistic analysis are definitive examples of ceramics using a refined 'cobalt', and therefore now may be assigned to the later production period of the first half of the 19th century.
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    On-site pXRF analysis of glaze composition and colouring agents of "İznik" tiles at Edirne mosques (15th and 16th-centuries)
    (Elsevier, 2019) Unsalan, Ozan; Bayraktar, Kutalmis; Colomban, Philippe; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştirmalari Merkezi (KUYTAM); N/A
    The production of the tiles in Ottoman Empire had begun as a continued workshop of Seldjuk ceramic art, and after this initial phase, its own technology was introduced into Ottoman art by local craftsmen. Iznik tiles are among the most appreciated pottery masterpieces, and wall decoration in tiles is a significant asset of Unesco World Heritage Edirne mosques. Rare glaze composition studies have been made, which justify the need for more comprehensive studies. We present here the first on-site elemental analyses performed with portable XRF instrument in four of the most representative mosques in Edirne (Sah Melek Pasa (1429), Muradiye (1435-1436), Uc Serefeli (1410-1447) and Selimiye (1569-1575)). A handheld 785 nm Raman spectrometer was used as a complementary technique to identify some pigments. About forty tiles have been analysed in this research. Additionally, two tiles from Yesilce Mosque (1442, Edirne) have been analysed at the Selimiye Foundation Museum. The weight percent of the elements measured with pXRF are normalized by Si amount in order to eliminate the variation due to the positioning shifts. Different glazing technologies are evidenced (Master of Tabriz Sn-free glazed tiles, Hunkar Mahfili Sn-poor glazed tiles, and Sn-(Bi) rich ones). At least three different cobalt ores have been used (with characteristic Cu, Ni, Mn and Bi content) in blue decors. Use of a chromium-based ore is demonstrated for some Selimiye Hunkar Mahfili tiles. The link between Sah Melek Pass and polychrome (mihrab) Muradiye tiles and Seldjuk production is established. On the contrary, the technology of Uc Serefeli and blue-and-white Muradiye tiles is unique and appears a precursor of 16th-century Iznik production. Bismuth, Sn/Pb, Co/Mn, and Co/Ni ratio appears very useful to compare the different glazes and to identify mining sources of cobalt.
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    Assessment of impressed/moulded ceramic wares excavated during the 2018-2019 seasons at the Iznik Tile Kilns Excavation and analysis results with a pXRF instrument on selected samples
    (İstanbul Üniversitesi Yayınevi, 2020) Arlı, Vesile Belgin Demirsar; Kaya, Şennur; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A
    Iznik reached the peak of its ceramic and tile production between the 14th- and 17th- centuries. Recent findings at the Iznik Tile Kilns Excavation carried out in the BHD coded excavation area in Iznik District center revealed that ceramics had been produced there using an impressed/moulded technique , which was widely used in non-Anatolian Islamic ceramic art. These types of ceramics, which are thought to have been intensively produced after Iznik passed into Ottoman administration in 1331, were classified into two main groups in terms of their forms and decorations. Moreover, during the 2019 excavation season, characterization studies were carried out using a portable XRF (pXRF) instrument on seven selected samples in order to determine the body, slip and glaze composition. The results showed that the sample without a slip contained calcium-rich clay (high calcium and high alumina). The analyses of the molding materials confirmed earlier studies which had determined that the paste used (the third type of paste) had been calcareous or calcium-rich clay. Moreover, the sample with slip contains a greater amount of quartz (55.4 wt%) than the sample without slip (44.2 wt%). of interest is that the sherd which is covered with a turquoise glaze contains 24.6 wt% lead-oxide (PbO) and 6 wt% tin oxide (SnO2). This glaze composition may indicate that the artifact was produced in the earlier period of Iznik production, namely at the end of the 15th century. Another glazed mold from among the samples analysed does not contain any tin oxide and has a higher amount of PbO which indicates a later production date (17th- century). The pXRF measurement results suggest that the mold may have been produced in an earlier period, and then glazed later for decorative and/or technical purposes. / 14-17. yüzyıllar arasında çini ve seramik üretiminde zirve yapan İznik’te, Anadoludışı İslam seramik sanatında yaygın kullanılan baskı/kalıba baskı tekniğindeseramiklerin de üretildiği, İznik İlçe merkezinde BHD kodlu kazı alanındayürütülen İznik Çini Fırınları Kazısı’nda ele geçen bulgularla netleştirilmiştir.İznik’in Osmanlı idaresine geçtiği 1331 yılından sonra yoğun olarak üretildiğidüşünülen bu seramikler, form ve bezeme açısından iki temel grupta toplanmıştır.Diğer yandan 2019 kazı sezonunda, bu tip seramiklerin karakterizasyonlarınıntespiti amacıyla seçilen yedi örnek üzerinde pXRF (Taşınabilir X-ışınlarıflüoresansı) cihazı ile hamur, astar ve sır bileşimlerine dair ölçümler yapılmıştır.Yapılan ölçüm sonuçlarına göre astarı olmayan örnekte hamur bileşiminin kilve kalsiyumca zengin olduğu anlaşılmıştır. Kalıp malzemeleri üzerinde yapılananalizlerle, kireçli veya kireç katkılı kil içeren hamur karışımının (3. tip) kullanıldığıdoğrulanmıştır. Astarlı örnekte ise kuvars miktarı (% ağ. 55.4), astarsız örneğegöre (% ağ. 44.2) daha fazladır. Firuze sırlı örneğin sırında %24.6 kurşun oksit(PbO) ve %6 kalay oksit (SnO2) tespit edilmiştir. Bu ölçümden bu örneğin erkendönem üretimi (15. yüzyıl sonu) olabileceği düşünülmektedir. Diğer sırlı kalıpörneğinin ölçüm sonucu ise (yüksek kurşun oksit içeren kalaysız sır), kalıbınmuhtemelen geç dönem (17. yüzyıl) üretimi veya önceden sırsız olarak kullanılankalıp malzemesinin sonradan dekoratif veya işlevsel olarak sırlanmış olabileceğinidüşündürür.
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    Characterization of a Jian-like sherd with the optical microscope, confocal Raman, wavelength-dispersive X-ray fluorescence, and portable XRF spectrometers
    (Wiley, 2020) Yıldırım, Sinem; Yılmaz, Suat; Birdevrim, Ahmet Nejat; N/A; Franci, Gülsu Şimşek; Akkaş, Tuğçe; Post Doctorate Student; Post Doctorate Student; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; N/A; N/A
    The ceramic masterpieces that belong to the private collections and art galleries are rarely studied with analytical instruments to define the authenticity, provenance, and characteristics of the materials because the scientific investigations are required to be solely noninvasive for characterizing the unfractured genuine objects. A monographic program, Blue Print, which was initiated by a German cultural heritage foundation, Art & Science Endowment Trust (ASET) Stiftung, aims at developing on-site research protocols for systematic research investigations on the fragmentary samples, with and without verifiable archeological contexts. For that reason, a combination of analytical techniques was carried out on a Jian-like sherd, which was assumed to be produced either as a genuine artifact between the 11th and late 14th centuries ad or as a Qing Dynasty copy (1644-1911 ad). Before slicing the sherd, confocal Raman microscopy was used to define the red glaze signature and the crystals formed on the glazed surface, whereas portable X-ray fluorescence (XRF) (pXRF) was used to define the composition of the glaze and body. Afterward, the sherd was cut and polished for the characterization with a zoom microscope, wavelength-dispersive XRF (WD-XRF), and Raman. The macroscopic examination revealed the presence of a glassy black colored interface layer, which was detected between the body and red glaze. The composition of the red glaze was determined with XRF and Raman spectrometers, and the presence of cadmium sulfoselenide (CdSxSe1-x, 0 <= x <= 1) with a high amount of zirconium (WD-XRF: 2.20 wt.%, pXRF: 1.55-wt.% ZrO2) was found. Additionally, Raman measurements evidenced the presence of epsilon-hematite crystals formed on the blackened red glazed surface. Unlike the glaze composition, the elemental content of the body is almost the same (Al2O3: 25.7 wt.%, Fe2O3: 8.19 wt.%, K2O: 2.54 wt.%) with the genuine Jian wares already documented by artistic and scientific examinations.
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    Handheld x-ray fluorescence (XRF) versus wavelength dispersive xrf: characterization of chinese blue-and-white porcelain sherds using handheld and laboratory-type XRF instruments
    (Sage, 2020) N/A; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; N/A
    Almost all archaeometric studies on Chinese ceramics are carried out on the excavation materials. Therefore, a detailed, comparable database that defines different workshops and production periods already exists. But the masterpieces preserved at museums, art galleries, and/or private collections, which are artistically considered as genuine artifacts, also require similar scientific investigations to define their provenance and authenticity. The research on artworks is only possible with the use of portable, noninvasive techniques that are developing daily concerning their capability of detection limits, rate of measurement, and ease of use. In this study, the results obtained with a handheld X-ray fluorescence (XRF) (also called portable XRF) and wavelength dispersive XRF instrument were compared to evidence the efficiency and drawbacks of the portable model. To achieve this goal, 12 sherds, which represent blue-and-white porcelains of Yuan and Ming Dynasties (China), were analyzed and the chemical composition of the body, glaze, and blue decor were identified. The comparison of the results with the measurements carried out on the excavation materials, which are produced in both southern and northern China, revealed the authenticity of the artifacts. Even sodium cannot be detected with portable XRF, the distinction of different production centers is possible with the detection of major (Mg, Al, Si, K, Ca), minor (Fe, Ti), and trace elements (Zr, Sr, Rb).
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    On-site pXRF analysis of body, glaze and colouring agents of the tiles at the excavation site of Iznik kilns
    (Elsevier, 2019) Demirsar Arli, Belgin; Kaya, Sennur; Colomban, Philippe; N/A; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; N/A
    The excavation at Iznik tiles kilns continues as the third period of the field mission. We present here the first on-site, non-invasive analyses performed with portable XRF instrument on twenty-five excavated tiles and two residue materials of the kiln. The shards studied were attributed to the productions from 14th- to 17th-centuries. The comparison was made by the discussion of characteristic elemental ratios selected from the ceramic technology criteria and PCA/Euclidean distances analysis. Three groups of body and glaze technologies were evidenced. We encountered that the amount of tin oxide in the glaze decreased over the centuries. Besides, two different types of fluxes were used in the glaze, some containing only potassium, and the others having potassium and calcium. The decors, which were investigated in this study were blue, turquoise, green, red colours, and black lines. A copper-iron mixture in the red areas was documented, which reflects the use of bornite.
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    Impact of the di(2-ethylhexyl) phthalate administration on trace element and mineral levels in relation of kidney and liver damage in rats
    (Springer, 2018) Karabulut, Gözde; Gök, Müslüm; Barlas, Nurhayat; N/A; Aydemir, Duygu; Franci, Gülsu Şimşek; Ulusu, Nuriye Nuray; PhD Student; Researcher; Faculty Member; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); Graduate School of Health Sciences; N/A; School of Medicine; N/A; N/A; 6807
    Di(2-ethylhexyl) phthalate (DEHP) is a widely used synthetic polymer in the industry. DEHP may induce reproductive and developmental toxicity, obesity, carcinogenesis and cause abnormal endocrine function in both human and wildlife. The aim of this study was to investigate trace element and mineral levels in relation of kidney and liver damage in DEHP-administered rats. Therefore, prepubertal male rats were dosed with 0, 100, 200, and 400mg/kg/day of DEHP. At the end of the experiment, trace element and mineral levels, glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6-PGD), glutathione reductase (GR) and glutathione S-transferase (GST) enzyme activities were evaluated in the serum, liver, and kidney samples of rats. Furthermore, serum clinical biochemistry parameters, organ/body weight ratios and histological changes were investigated to evaluate impact of DEHP more detailed. Our data indicated that sodium (Na), calcium (Ca), potassium (K), lithium (Li), rubidium (Rb) and cesium (Cs) levels significantly decreased, however iron (Fe) and selenium (Se) concentrations significantly increased in DEHP-administered groups compared to the control in the serum samples. On the other hand, upon DEHP administration, selenium concentration, G6PD and GR activities were significantly elevated, however 6-PGD activity significantly decreased compared to the control group in the kidney samples. Decreased G6PD activity was the only significant change between anti-oxidant enzyme activities in the liver samples. Upon DEHP administration, aberrant serum biochemical parameters have arisen and abnormal histological changes were observed in the kidney and liver tissue. In conclusion, DEHP may induce liver and kidney damage, also result abnormalities in the trace element and mineral levels.
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    PublicationOpen Access
    Distinguishing genuine Imperial Qing Dynasty porcelain from ancient replicas by on-site non-invasive XRF and Raman spectroscopy
    (Multidisciplinary Digital Publishing Institute (MDPI), 2022) Colomban, P.; Gironda, M.; d'Abrigeon, P.; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM)
    The combined use of non-invasive on-site portable techniques, Raman microscopy, and X-ray fluorescence spectroscopy on seven imperial bowls and two decorated dishes, attributed to the reigns of the Kangxi, Yongzheng, Qianlong, and Daoguang emperors (Qing Dynasty), allows the identification of the coloring agents/opacifiers and composition types of the glazes and painted enamels. Particular attention is paid to the analysis of the elements used in the (blue) marks and those found in the blue, yellow, red, and honey/gilded backgrounds on which, or in reserve, a floral motif is principally drawn. The honey-colored background is made with gold nanoparticles associated with a lead- and arsenic-based flux. One of the red backgrounds is also based on gold nanoparticles, the second containing copper nanoparticles, both in lead-based silicate enamels like the blue and yellow backgrounds. Tin and arsenic are observed, but cassiterite (SnO2) is clearly observed in one of the painted decors (dish) and in A676 yellow, whereas lead (calcium/potassium) arsenate is identified in most of the enamels. Yellow color is achieved with Pb-Sn-Sb pyrochlore (Naples yellow) with various Sb contents, although green color is mainly based on lead-tin oxide mixed with blue enamel. The technical solutions appear very different from one object to another, which leads one to think that each bowl is really a unique object and not an item produced in small series. The visual examination of some marks shows that they were made in overglaze (A608, A616, A630, A672). It is obvious that different types of cobalt sources were used for the imprinting of the marks: cobalt rich in manganese for bowl A615 (Yongzheng reign), cobalt rich in arsenic for bowl A613 (but not the blue mark), cobalt with copper (A616), and cobalt rich in arsenic and copper (A672). Thus, we have a variety of cobalt sources/mixtures. The high purity of cobalt used for A677 bowl indicates a production after similar to 1830-1850.
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    PublicationOpen Access
    Cobalt and associated impurities in blue (and green) glass, glaze and enamel: relationships between raw materials, processing, composition, phases and international trade
    (Multidisciplinary Digital Publishing Institute (MDPI), 2021) Colomban, Philippe; Kırmızı, Burcu; Franci, Gülsu Şimşek; Researcher; Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM)
    Minerals able to colour in blue (and green in combination with yellow pigments) are limited in number and geologically. After presenting a short history of the use of cobalt as a colouring agent of glass, glaze and enamel in the Western/Mediterranean, Islamic and Asian worlds since Antiquity, we will present the different forms (dissolved ions, natural and synthetic crystalline phases/pigments) of cobalt and associated elements regarding primary (transition metals) and secondary geological deposits (transition metals and/or arsenic, bismuth, silver). Attempts to identify the origin of cobalt have been made by many authors considering the associated elements but without considering the important modifications due to different processing of the raw materials (extraction/purification/formulation). We review the information available in the ancient reports and present literature on the use of cobalt, its extraction and production from the ores, the different geological sources and their relationship with associated elements (transition metals, bismuth, arsenic, and silver) and with technological/aesthetic requirements. (Partial) substitution of cobalt with lapis lazuli is also addressed. The relative application of non-invasive mobile Raman and pXRF analytical instruments, to detect mineral phases and elements associated with/replacing cobalt is addressed, with emphasis on Mamluk, Ottoman, Chinese, Vietnamese and Japanese productions. The efficiency of Ni-Zn-As diagram proposed by Gratuze et al. as a classification tool is confirmed but additionally, CoO-Fe2O3?MnO and CoO-NiO-Cr2O3 diagrams are also found as very efficient tools in this research. The relationship between the compositional data obtained from the artefacts and historical questions on the origin and date of their production are discussed in order to obtain a global historical view. The need of a better knowledge of (ancient) deposits of cobalt ores and the evolution of cobalt ore processing with time and place is obvious.