PRODUCTION AND SUPPLY OF CERAMIC OIL LAMPS IN HELLENISTIC AND EARLY ROMAN NEA PAPHOS, CYPRUS: INTEGRATED TYPOLOGICAL, CHRONOLOGICAL AND PROVENANCE STUDIES

This paper presents the results of a multipronged approach to the study of the Hellenistic and Early Roman ceramic oil lamps excavated at the Agora of Nea Paphos in Cyprus. The assemblage was studied macroscopically, and selected samples were analysed through WD-XRF spectroscopy and thin section petrography, combined with refiring tests. The integrated results revealed that local production changed through time in terms of lamp shapes, manufacturing techniques and clay recipes, while imported lamps originated from a range of sources. The transformations seen in the local production correlate with changes in the origin of imported lamp supply and the impact of other centres on the local lamp manufacture. These patterns in production and supply could be most likely associated with political transformations and urban development.

Graffiti Characterization Prior to Intervention in the Punta Begoña Galleries (Getxo, North of Spain): Raman and XRF Spectroscopy in the Service of Restoration

The Historical and Cultural Heritage of Punta Begoña Galleries in Getxo (Bizkaia, North of Spain) are currently in restoration after being abandoned for years. For that reason, many graffiti, which directly affect the wall paintings, appear on most of their walls. Moreover, several graffiti overlap each other, which makes their removal more difficult. For all these reasons, the chemical characterization of these pigments is a priority to optimize the cleaning and consolidation treatments of wall paintings. That being the case, an analysis based on Raman spectroscopy and X-ray fluorescence was carried out to obtain information to help conservators remove the graffiti without damaging the mural paintings and the support. Nevertheless, the first step, using X-ray fluorescence and Raman spectroscopy, involved the need for a database to compare the results and identify the compounds. Thus, different commercial inks were elementally and molecularly characterized to complete the existing databases. After this, an analysis of the inks was carried out that noted the presence of several organic pigments, such as phthalocyanines. Inorganic pigments such as titanium oxide were identified as well. After the analysis, the selection of the best removal process could be carried out to provide the most effective treatment, avoiding the “trial-and-error” classical practice.

Feasibility study on the use of elemental profiles to authenticate aromatic rice: the case of Basmati and Thai rice

Among the thousands of existing rice varieties, aromatic rice has increasingly attracted consumer’s preference in recent years. Within aromatic rice, Basmati, cultivated in some regions in Pakistan and India, is highly demanded. Other aromatic rice, cultivated in specific regions, for instance in Thailand (commonly referred to as Jasmine Thai rice), are also highly appreciated by consumers. In this work, the elemental profiles of commercially available rice samples (17 Basmati, 11 Thai, and 7 Long Grain rice) were determined by energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy. The mass fractions of P, Cl, S, K, Fe, Cu, and Zn were significantly different (95% confidence interval) between Basmati and Thai rice and between Thai and Long Grain rice; only Cl, S, and Zn were significantly different between Basmati and Long Grain rice. Multivariate evaluation of the results combining soft independent modelling by class analogy (SIMCA) and partial least square discriminant analysis (PLS-DA) allowed the correct classification (true positives) of 94.1, 85.6, and 100% of the Basmati, Long Grain, and Thai rice, respectively. The specificity (true negatives) of Basmati, Long Grain, and Thai was 94.4, 82.1, and 100%, respectively.

Study on LOD of Trace Elements by XRF Analysis Using BP & Adaboost and PLS Methods

Poisonous elements such as Cd, Hg, Pb, As, Zn, Cr, Ni, Cu etc. are commonly observed in polluted soil and hard to be removed by soil microbes. It is of significant importance to identify these poisonous elements in-situ and accurately both in qualitative and quantitative sense. In order to determine the Limit of Detection (LOD) for trace elements (e.g. Cadmium) in polluted soil samples based on Energy Dispersion X-ray fluorescence (ED-XRF) spectroscopy, approximately 60 national standard soil samples were collected and measured by an XRF equipment. The authors firstly utilize the Method Detection Limit (MDL) algorithm to calculate the LOD of trace elements, and then develop a new model called Back Propagation Adaboost (BP & Adaboost) classification to determine the LOD based on a presumed tolerance error (e.g. 5%). Furthermore, the Multivariate- Partial Linear Squares Regression (M-PLSR) method is applied to regress the data and validate the LOD values. In this paper, the authors make a detailed comparison between the BP algorithm and the BP & Adaboost classification algorithm under different presumed detection limits, and it is found that the detection results achieved the best qualitative prediction of Cd element (i.e. whether it exists in soil) based on the BP & Adaboost algorithm. The experimental results indicate that the BP & Adaboost algorithm is the most effective method to determine and decrease the LOD of trace element (such as Cd) in soil. The advantages are: It combines the classification effects of several weak classifiers, and determines that the LOD of element Cd is 0.5mg/kg with prediction error rate of 5%. Compared with the traditional methods like MDL, it is proved that the BP & Adaboost algorithm is appropriate to be used in the terms of prediction accuracy. It is recommended that the BP & Adaboost classification method shall be used for material analysis on XRF spectroscopy.