Energy Dispersive X-ray Fluorescence Research Articles

Application of laboratory micro X-ray fluorescence devices for X-ray topography

It is demonstrated that high-resolution energy-dispersive X-ray fluorescence mapping devices based on a micro-focused beam are not restricted to high-speed analyses of element distributions or to the detection of different grains, twins and subgrains in crystalline materials but can also be used for the detection of dislocations in high-quality single crystals. Si single crystals with low dislocation densities were selected as model materials to visualize the position of dislocations by the spatially resolved measurement of Bragg-peak intensity fluctuations. These originate from the most distorted planes caused by the stress fields of dislocations. The results obtained by this approach are compared with laboratory-based Lang X-ray topographs. The presented methodology yields comparable results and it is of particular interest in the field of crystal growth, where fast chemical and microstructural characterization feedback loops are indispensable for short and efficient development times. The beam divergence was reduced via an aperture management system to facilitate the visualization of dislocations for virtually as-grown, non-polished and non-planar samples with a very pronounced surface profile.

Real-time chemostratigraphy at wellsite; removing drilling uncertainties

Real-time chemostratigraphy is a workflow deployed at wellsites to remove stratigraphic uncertainty and support drilling operations. This study presents the chemostratigraphic wellsite workflow which, during drilling operations, support either the placement of casing points (using predefined geochemical markers to target a depth above a specific stratigraphic feature) or aid geosteering. Geosteering is typically employed during the drilling of a horizontal well and is done to keep the drill within a certain zone or horizon to maximise production. Wellsite chemostratigraphy has been effectively deployed to wellsites within multiple basins around the globe and has recently been utilised in the Perth Basin. The wellsite workflow starts before the deployment, with offset wells analysed by inductively coupled plasma (ICP) spectroscopy within a laboratory-based setting. This builds the correlative element-based framework and identifies the trends required to assist with either core placement, casing point, or geosteering. Samples are analysed by energy dispersive x-ray fluorescence units (these data are then used to confirm the zone previously defined) and can be identified at wellsite using the onsite tool, the selected elements of which are those less likely to be affected by drilling mud contamination and loss of circulation material (LCM). However, during drilling operation, there may be instances where LCM must be added to the drilling muds, which may have an effect on the data quality for certain elements. With a dedicated ICP spectrometry elemental database behind the wellsite operation, machine learning tools may be employed to ‘repair’ correlation critical elements.

Application of handheld/portable spectroscopic tools to the identification, inner stratigraphy and mapping of archaeological metal artefacts

Field handheld/portable instrumentations, such as in-situ geochemical analyzers, have the potential to assist efficiently targeted geochemical archaeometry campaigns in detecting and quantifying specific elements. Non-destructive portable energy dispersive x-ray fluorescence and micro-destructive handheld laser-induced breakdown spectroscopy (LIBS) instrumentation were utilized to investigate the elemental composition, internal stratigraphy by depth profiling and microscale compositional mapping of five copper and two iron alloy artefacts collected from various ancient graves in the Minervino Murge area, Apulia, Italy. The primary elements identified by both techniques included Cu, Sn and Pb in copper alloys, and Fe with minor amounts of Cu and Pb in iron alloys. Furthermore, the elements Al, Ca, Si, Mg, Na and K, mostly originated from soil contamination, and the trace elements Sb, Ni and Zn were detected. The satisfactory performance of both techniques was assessed by their capacity to provide reproducible elemental composition data. Finally, the depth profile and mapping achieved by LIBS contributed to understanding the metal processing and history of the objects studied, so confirming both techniques to be robust analytical tools in outdoor archaeology and archaeometry campaigns.

Fast, accessible and reliable method for elemental analysis of metals in solution by ED-XRF spectroscopy

The measurement of metals in solution is usually performed using inductive coupled plasma hyphenated techniques or atomic absorption. Although very sensitive and accurate, these analytical techniques are quite expensive and do not allow field measurements. The present work takes advantage of energy-dispersive X-ray fluorescence (ED-XRF) ease-of-use features to determine the concentration of rare earth elements (Y, Pr, Nd, Eu) and others (S, Fe, Ni, Cu, Zn) in aqueous solutions, after appropriate sample treatment. The approach turned out to be a reliable and very convenient procedure for field analysis. The simplicity, speed and reliability of the methodology used combined with the possibility of simultaneous analysis and low cost of the method can be advantageous in industrial context. The approach relies on the suspension of the target solutions in a cellulose matrix that is further converted into a pellet for direct analysis. Calibration curves obtained by regression analysis at 5% significance are shown for a variety of elements (S, Fe, Ni, Cu, Zn, Y, Pr, Nd, Eu) with correlation coefficients between 0.9555 and 0.9980. Higher coefficients of variance were obtained for the calibration of S and Pr due to low sensitivity and the overlapping with the L lines of Nd, respectively. The performed calibrations were not affected by the presence of other analytes in the matrix. Results obtained showed that it is possible to use the proposed methodology to accurately quantify d and f block metals in aqueous solutions by ED-XRF after sequestering the chemical content into a cellulose powder matrix and further processing into a pellet.Graphical

Investigating the Characterization and Grindability Behaviour of Farin-lamba Cassiterite toward Effective Tin Oxide Production

Cassiterite has been an essential source of tin; its exploration and exploitation have become a priority worldwide. The effective beneficiation of cassiterite depends mainly on its grindability and effective liberation. The Modified Bond's grindability test is a method used to determine the work index, which is crucial in estimating the energy needed to grind an ore. This is crucial during mineral processing, as a slight deviation would affect the company's operating expenditure (OPEX). This study investigates the work index for Farin-Lamba cassiterite with reference to silica sand sourced from Igbokoda. The test ore (cassiterite) was analyzed using Energy Dispersed X-ray fluorescence spectrometer (ED-XRS), Petrographic Analysis, and Scanning Electron Microscope equipped with an Energy Dispersive Spectrum (SEM-EDS) to understand their chemical and mineralogical characteristics in relation to their grindability. The test ore and the reference material (silica sand) underwent comminution using 500g of each to a 100% passing 500 μm array of sieves arranged in (√2) series from 500μm to 63μm onto an automatic sieve shaker. The chemical and mineralogical analysis revealed the presence of gangue such as SiO2 and Al2O3, which increases the energy needed during communition; further, the presence of rough and large grain size in the ore also increases the energy needed for communition. The results were subjected to Gaudin Schuman's equation to determine the ore's work index, which was 14.664 KWh/ton for the test ore, which is standard for cassiterite, which ranges from 10-15 kWh/ton. Further, the energy needed for comminution was calculated to be 33.7272 Kwh, providing valuable insights into the energy efficiency of the grinding process. The evaluation of the grindability of Farin-Lamba cassiterite in relation to the reference ore not only contributes toward understanding the ore processing dynamics but also provides information needed for the optimization of energy consumed during the process of tin oxide production.

Studies on the Authorship of Albumen Vintage Photographs: A Combined Experimental and Chemometric Approach.

The differences in albumen photographs from vintage photographic studios were identified by energy-dispersive X-ray fluorescence spectroscopy and Fourier transform infrared spectroscopy. The results inspired the concept of finding common features characteristic of a given photographic studio. The obtained measurement data (i.e., positions of vibrational bands for characteristic groups of albumen and the mass contents of chosen elements) were analyzed chemometrically by employing the Principal Component Analysis (PCA). The PCA technique allowed us to reduce the number of relevant experimental parameters characterizing the unique features of the photographic objects. The two major components were able to distinguish the photographic objects in terms of their authorship and the time to produce a photograph. The method developed was examined for a selected group of photographs consisting of albumen prints from three Polish photographic ateliers. To validate ED-XRF measurements and, consequently, the chemometric findings, reference albumen photo samples were designed and prepared. The empirical functional relationships between the content of photochemically reduced silver particles on the photographic paper and several physicochemical factors, including time of exposure to UV light, AgNO3 concentration in a fixed bath, and concentrations of other additives, were proposed. These results can be used for the prediction of the experimental conditions under which the investigated photographs were developed.

ADSORPTION OF CATION DYE USING ACTIVATED CARBON DERIVED FROM GOLDEN SHOWERSEED POD ( C ASSIA FISTULA)

ADSORPTION OF CATION DYE USING ACTIVATED CARBON DERIVED FROM GOLDEN SHOWERSEED POD ( C ASSIA FISTULA)

ACTIVATED CARBON DERIVED FROM GROUNDNUT SHELL AND RICE HUSK FOR THE ADSORPTION OF HEAVY METALS IN TANNERY WASTEWATER

The Effluents from tanneries are considered to be one of the major environmental pollutants from industries. The challenge from leather processing arises from the nature and quality of the chemicals used along with the amount of wastes generated and discharged. Heavy metals present in tannery wastewater pose a significant risk to both the environment and public health. This study investigates the use of activated Carbon produced from Composite of Groundnut shell and Rice husk (GR-AC) to remove heavy metals (Pb, Cr and Cd) from tannery wastewater. The raw material was carbonized at temperature of 400 ͦ C for 1 hour to obtain bio char. The obtained char was impregnated with NaOH and H 3PO 4 for 24 hours thereafter, filtered and washed several times until a neutral pH was obtained. A measured amount of the adsorbent, 0.5g was introduced into 250mL vessel with 50mL wastewater, it was stirred at 250rpm for 60minutes and later subjected to centrifugation and the concentrations of residual Lead, Chromium and Cadmium was determined using Flame Atomic Absorption Spectrometry. The produced adsorbent was characterized using Fourier transform infrared (FTIR) spectroscopy, Energy-dispersive X-ray fluorescence (EDXRF) and scanning electron microscopy (SEM), elemental composition analysis. The effects of adsorbent dosage and contact time on the adsorption process were studied in a batch system. From the research conducted, it shows that pH, adsorbent dosage, contact time, initial Concentration and temperature plays a vital role in the uptake of heavy metals. Optimal conditions for effective adsorption were determined at a pH range of 7 to 8, an adsorbent dosage of 0.5g, contact time of 60 min and a temperature of 40 0C. The maximum adsorption capacities of Pb, Cr and Cd adsorbed onto GR-AC were found to be 98.2, 82.4 and 75.2 mg/g respectively. Therefore, the GR-AC can be effectively utilized as agricultural waste to remove heavy metals in tannery effluents.

Investigation of the X‐ray fluorescence technique in the characterization of Ni coatings applied to historical heritage studies

AbstractHistorical heritage pieces allow a better comprehension of the characteristics of different civilizations over time. The characterization of such pieces is of paramount importance for their preservation. Energy‐dispersive X‐ray fluorescence (EDXRF) is recommended for this application, mostly because it is non‐destructive and the equipment is portable. However, one of its limitations is the difficulty in separating the signal from the substrate and the coating of multilayered samples, as it does not provide depth resolution. This project investigates the application of EDXRF in the characterization of metallic coatings, in the context of historical heritage. The elemental concentration of electrodeposited Ni coatings onto carbon steel substrates was obtained from EDXRF analyses. The relationship between the layer thickness and the variation of the Kα/Kβ intensity ratio of nickel peaks was exploited and the thicknesses of the coatings were estimated through EDXRF measurements. For comparison, particle‐induced x‐ray emission spectroscopy and scanning electron microscopy of the cross‐section were employed, providing a depth profile of the coatings. The estimated thicknesses from EDXRF analysis were comparable to those observed in the microscopy images for thinner films (up to 8 μm). On the other hand, for thicker films, the thicknesses were underestimated, due to the technique's depth limit and matrix effects, as secondary absorption. Despite these limitations, EDXRF remains valuable for evaluating cultural heritage pieces, often providing sufficient information to address authenticity concerns or to guide restoration processes. A case study was also performed to apply the methodology discussed on historical metallic pieces.

On the Methodology of the Quantitative Analysis of Fe–Cr–Mn–Mo–N–C Steels Reinforced with Oxide and Nitride Particles Using an Energy Dispersive X-Ray Fluorescence Spectrometer BRA-135F

On the Methodology of the Quantitative Analysis of Fe–Cr–Mn–Mo–N–C Steels Reinforced with Oxide and Nitride Particles Using an Energy Dispersive X-Ray Fluorescence Spectrometer BRA-135F

Characterization of 17th century archaeological metallic statuettes using combined neutron tomography and neutron diffraction

A combination of neutron computed tomography and neutron diffraction analysis has been studied to demonstrate the efficacy of employing neutron-based methodologies to investigate brass metallic statuettes, thereby shedding light on their structural and phase characteristics, all the while obviating the need to dissect the sample physically. In order to corroborate the findings obtained from the neutron-based techniques, supplementary methodologies such as Energy Dispersive X-ray Fluorescence were employed to extract elemental information and validate the results. These preliminary findings draw attention to the potential of neutron imaging to unveil intricate information regarding the techniques and components employed by artisans of antiquity in the production of Indian brass artifacts. We were also able to discern concealed structural attributes within metallic statuettes, as well as ascertain the precise phase composition of the brass alloy, thus further enriching our understanding of manufacturing practices of brass statuettes in the 17th-century era.

Characterizations and Solubility Profile of Novel Senary SiO2–CaO–Na2O-P2O5–CaF2–SrO Glass Structure Modified with Nb2O5

The solubility/degradability of bioactive glasses play crucial role in bone tissue engineering applications owing to the release of ions from their structure, which exert therapeutic effects on tissues. The present study evaluates the findings of a detailed investigation on the main features and solubility behaviors of newly formulated Nb incorporated glasses (Nb-BGs). New glass formulation in SiO2–CaO–Na2O–P2O5–CaF2–SrO–xNb2O5 (x: 0.0, 0.5, 1.0, and 1.5 mol. %) system was successfully synthesized by melt-quenching technique. Glass composition was verified with Energy Dispersive X-ray Fluorescence spectrometer analysis and its amorphous nature, functional groups of the matrix and morphological features were identified via X-Ray diffraction analyses, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscope analysis, respectively. Network connectivity (NC) of the Nb-BGs was assessed with respect to the role of Nb2O5 in the glass matrix as network former, modifier, or both. In order to evaluate the in vitro solubility of Nb-BGs, released concentrations of particular ions from the glass compositions were determined at certain time points and comprehensively discussed with several mathematical models such as zero-order, first-order, second-order, Higuchi, and Korsmeyer-Peppas for the first time. Results showed that the incorporation of Nb2O5 (up to 1.5 mol. %) increased the density, oxygen density as well as NC values of newly formulated glasses. Si, Na and Ca ions which play a main role in well-defined Hench’s mechanism followed mostly second-order release kinetics for all glasses in the mathematical models studied. When the Nb content increase (to 1.5 mol. %) in glass composition, the release mechanism of Si ion according to Korsmeyer-Peppas model shifts from the diffusion mechanism to an erosion-dominant release mechanism.

Determination of Sulphur Dioxide (SO<sub>2</sub>) Air Emission of Refined Petroleum Products by Emission Factor Approach for Air Pollution Control

Air pollution control is a safe method for achieving a sustainable environment and can be accomplished by adequately monitoring pollutants that pose significant environmental risks. The combustion of sulfur-containing petroleum products has been a major concern for several decades. Therefore, this study was aimed at determining sulfur levels in refined petroleum products such as Premium Motor Spirit (PMS), Automotive Gas Oil (AGO), and Dual-Purpose Kerosene (DPK). It also investigated the air quality implications of sulfur levels and estimated the contribution of the refinery’s products to sulfur dioxide air emission. Fuel samples were collected from the Warri Refining and Petrochemical Company (WRPC) in Nigeria and analyzed using Ultraviolet-visible spectrophotometer (UV-Vis) and Energy-Dispersive X-ray Fluorescence (EDXRF). Sulfur levels were determined at 425 nm wavelength, and sulfur dioxide air emission were estimated for seven consecutive years from 2010 to 2016 using the emission factor approach. The densities of PMS, AGO, and DPK were 0.77 kg/l, 0.832 kg/l, and 0.82 kg/l respectively. The levels of sulfur in PMS, AGO, and DPK were 2.007 x 10<sup>-4</sup> %, 6.970 x 10<sup>-5</sup> wt%, and 4.233 x 10<sup>-5</sup> wt% respectively from UV-Vis technique and 0.016, 0.087 and 0.029% respectively for EDXRF technique were found below the sulfur limit of 0.015 %, 0.005 % and 0.015 % for PMS, AGO and DPK respectively specified by Standard Organization of Nigeria (SON) specifications of 0.1, 0.5 and 0.15wt% for PMS, AGO and DPK respectively. The annual sulfur dioxide emissions were obtained for seven consecutive years from 2010 to 2016. The results from UV-VIS were observed to have the highest SO<sub>2</sub> emission of 0.1718 tons for PMS in 2011, 0.2593 tons in 2010 for AGO, and 0.0974 tons for DPK in 2010, while the lowest emission was observed to be 0.029 tons for PMS in 2015, 0.0362 tons in 2015 for AGO and 0.0181 tons for DPK also in 2015. The results from EDXRF technique were observed to have the highest SO<sub>2</sub> emission of 13.6939 tons for PMS in 2012, 323.6881 tons for AGO in 2010, and 66.7147 tons for DPK also in 2010, while the lowest emissions for PMS, AGO and DPK were all observed in 2015 to be 2.3122, 45.1872, and 12.4182 tons respectively. The study concluded that the refinery complied with the set requirements.

Influence of trace elements changes in the cerebellum on the rat’s behavior in elevated plus maze in the early period of mild blast-induced traumatic brain injury

The aim of the current study was to determine whether there are changes in brain trace elements of rats with blast-induced trauma and if these changes affect behavior in the elevated plus maze. Materials and methods. The study was carried out on 126 sexually mature male Wistar and were divided into 3 groups: Experimental – exposed to a shock wave 26.4 ± 3.6 kPa (n = 42); Sham (n = 42), the animals of which were subjected to inhalation anesthesia with halothane and fixation in a horizontal position; and Intact (n = 42). Behavior was study in elevated plus maze. The duration of presence in the open and closed arms, the number of stands, the duration of grooming was recorded in all groups of rats for 3 minutes. After, the animals were euthanized with halothane, followed by removal of the brain. The cerebellum was completely separated for spectral analysis using energy dispersive X-ray fluorescence analysis (EDRFA) on the analyzer EXPERT 3 XL. Results. Results showed significant changes of cognitive activity in experimental group which are indicate functional disorders of the cerebellum in the form of maladaptation in space with subsequent inhibition of motor centers. Cu/Fe ratio was decreased in the 14th and 21st days and increased in the 28th. Cu/Zn ratio was decreased on the 14th day. Zn/Fe ratio was higher on the 14th and 28th days. The existence of correlations between changes in trace elements and behavioral disorders in experimental rats was established. Conclusions. In the early period of blast-induced traumatic brain injury, cerebellar dysfunction in the form of spatial maladaptation with subsequent depression of motor centers was observed in the experimental rats Correlation analysis showed the presence of different strengths and directions of relationships between the ratios of Cu/Fe, Cu/Zn and Zn/Fe in the cerebellum and behavioral indicators in the elevated plus maze (duration of stay in open and closed arms, grooming and vertical motor activity) of experimental rats.

Risk Assessment and Sources Apportionment of Toxic Metals in Two Commonly Consumed Fishes from a Subtropical Estuarine Wetland System.

The widespread occurrence of heavy metals in aquatic environments, resulting in their bioaccumulation within aquatic organisms like fish, presents potential hazards to human health. This study investigates the concentrations of five toxic heavy metals (Pb, Hg, Zn, Cu, and Cr) and their potential health implications in two economically important fish species (Otolithoides pama and Labeo bata) from a subtropical estuarine wetland system (Feni estuary, Bangladesh). Muscle and gill samples from 36 individual fish were analyzed using energy dispersive X-ray fluorescence (EDXRF). The results revealed that the average quantities of heavy metals in both fishes' muscle followed the declining order of Zn (109.41-119.93 mg/kg) > Cu (45.52-65.43 mg/kg) > Hg (1.25-1.39 mg/kg) > Pb (0.68-1.12 mg/kg) > Cr (0.31-5.82 mg/kg). Furthermore, Zn was found to be present in the highest concentration within the gills of both species. While the levels of Cu, Zn, and Cr in the fish muscle were deemed acceptable for human consumption, the concentrations of Pb and Hg exceeded the permissible limits (>0.5 mg/kg) for human consumption. Different risk indices, including estimated daily intake (EDI), target hazard quotient (THQ), hazard index (HI), and carcinogenic or target risk (TR), revealed mixed and varying degrees of potential threat to human health. According to the EDI values, individuals consuming these fish may face health risks as the levels of Zn, Cu, and Cr in the muscle are either very close to or exceed the maximum tolerable daily intake (MTDI) threshold. Nevertheless, the THQ and HI values suggested that both species remained suitable for human consumption, as indicated by THQ (<1) and HI (<1) values. Carcinogenic risk values for Pb, Cr, and Zn all remained within permissible limits, with TR values falling below the range of (10-6 to 10-4), except for Zn, which exceeded it (>10-4). The correlation matrix and multivariate principal component analysis (PCA) findings revealed that Pb and Cr primarily stemmed from natural geological backgrounds, whereas Zn, Cu, and Hg were attributed to human-induced sources such as agricultural chemicals, silver nanoparticles, antimicrobial substances, and metallic plating. Given the significance of fish as a crucial and nutritious element of a balanced diet, it is essential to maintain consistent monitoring and regulation of the levels and origins of heavy metals found within it.

The Technical Examination of Nineteenth-Century Artists' Pigments from John Opie’s Paintbox

ABSTRACT St Agnes Museum, Cornwall, currently holds in its collections a paint box with a metal plaque reading ‘John Opie 1806’, containing pigments and other artists’ materials. John Opie produced hundreds of oil paintings until his untimely death in 1807 and was a well-known and successful painter of portraits and historical scenes. However, his work has been little studied, in comparison to his contemporaries such as Joshua Reynolds. This paper discusses the identification of the pigments in the paint box using infrared spectroscopy (FTIR-ATR), optical microscopy, scanning electron microscopy with energy dispersive spectroscopy (SEM-EDX), Raman spectroscopy (SERS) and X-ray fluorescence (XRF). Seven pigments have been identified as ultramarine, lead white, fustic and carmine lakes, carbon black (likely ivory), hematite, and burnt sienna, consistent with the bottle labels where present. The identification has been further confirmed using historical literature, which has shown that the pigments are likely to be contemporary with the stated date of 1806. This information adds to the body of knowledge about the artist specifically, and the artists pigments generally available at the time.

ZnS@ fluorenone derived multifunctional quantum dots for simultaneous recognition of bovine serum albumin (BSA) and copper ions (Cu2+) in aqueous blood and urine samples

An efficient synthesis of water-stable and fluorescent ZnS quantum dots has been executed beginning with its organic predecessor possessing fluorenone for sensing bovine serum albumin (BSA) among other proteins. Moreover, the organic predecessor of quantum dots has also been utilized for sensing of F- ions with binding constant of 1.8 × 104 M−1. Various spectroscopic techniques such as high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (PXRD), UV-visible (UV-vis), Fourier transform infrared (FTIR), thermogravimetric (TGA), Energy dispersive X-ray analysis (EDX), circular dichroism (CD) and Fluorescence (FL) spectroscopy have been utilized for the characterization of the developed quantum dots. The emission properties of quantum dots made them useful for the sensing of BSA and Cu2+ accompanied with secondary sensing of urea. The LODs value for BSA and Cu2+ were calculated as 213 and 211 nM, respectively. Demonstrating remarkable efficacy, these quantum dots have been successfully employed for the discernment of BSA in human blood and urine samples, achieving an outstanding recovery rate of up to 99.8%.

XRF calibration with low-cost samples and implementation for quantification of inorganic elements in lipsticks

In this paper, the preparation of low-cost samples, for the calibration of an energy–dispersive X-ray fluorescence system is presented. The entire procedure is proposed as an undergraduate or postgraduate student laboratory activity, which aims to familiarize students with the procedure of calibration of a spectroscopy-based analytical method through the XRF technique. Furthermore, the use of XRF for the determination of elemental concentrations in samples related to students’ interests, was attempted.

Influence of fluoride characteristics on tooth surface protection in an erosive condition: A multifaceted characterization approach.

To evaluate the effect of fluoride consistency and composition to protect enamel and dentin against the dental erosion. Bovine enamel and dentin specimens were treated with artificial saliva, neutral fluoride gel (NFG), acidulated phosphate fluoride gel (AFG), neutral fluoride foam (NFF), and acidulated phosphate fluoride foam. The samples were subjected to cycling. Micro energy-dispersive X-ray fluorescence spectrometry, surface roughness (Ra), contact angle (CA), and scanning electron microscopy (SEM) were performed. Composition, CA and Ra data were analyzed by ANOVA and multiple comparison test (p < 0.05). The dentin protected had a significantly higher mineral content than in the control. Eroded unprotected enamel had higher Ra values than normal surfaces. Fluoride treatments increased the Ra in dentin samples. AFG increased the CA in enamel. Fluoride foams increased CA in dentin with reduced mineral loss. SEM analysis found a deposited layer on enamel treated with AFG and remnants of deposits on dentin treated with NFG and NFF. Regardless of the form of application, fluoride provided protection against erosion, however with different levels. Applying the adequate fluoride form is relevant since the formulations have different effects on both enamel and dentin.

Maximization of the blue-white contrast of ancient porcelain decorations from Jingdezhen imperial kiln by Co-spinel formation

By analyzing the chromaticity values of the ancient blue-and-white porcelain combined with the imitated experiment, the color information is quantified and ‘color dispersion’ mechanism is clarified. Energy Dispersive X-Ray Fluorescence (EDXRF), field emission scanning electron microscopy (FE-SEM), the advanced focused ion beam transmission electron microscopy (FIB-TEM) technique, etc, were used to study the characteristics and the ‘color dispersion’ mechanism of the blue-and-white porcelain in Jingdezhen imperial kiln. The ‘color dispersion’ of the blue-and-white porcelain is mainly caused by Co-element structure stability, which is verified by the archaeological experiment results. Blue-and-white decoration lines diffusion length (named as ‘color dispersion’) are long (i.e. fuzzy) which has few or no spinel crystals in the body-glaze interaction layer of the blue-and-white porcelain. However, the blue and white porcelain with the clear lines has a large number of spinel crystals. The experimental results enrich the literature on the history of ceramic manufacturing techniques in Jingdezhen.