Results Of X-ray Fluorescence Analysis Research Articles

Evaluation of the use of polyvinyl alcohol in the manufacture of pressed samples for X-ray fluorescence analysis

The reliability of the results of X-ray fluorescence analysis (XRF), which is widely used in determination of the elemental composition of various materials, largely depends on the quality of sample preparation. When producing pressed tablets for X-ray fluorescence analysis of trace elements, a binder is often used in a powder form, which requires significant time for thorough homogenization. We present the results of applicating a polyvinyl alcohol solution as a binder in the manufacture of pressed samples without using a substrate in determination of microelements by XRF. The parameters for obtaining a durable tablet with a homogeneous composition that matches the condition of minimum impact on the intensity of the analytical lines of the elements being determined are presented. It is shown that the optimal sample weight for the proposed method of producing pressed tablets is 7 g with the addition of polyvinyl alcohol in a ratio of 7:1, the optimal drying time for the tablet after pressing is 1 hour. The calculated variation coefficients of the analytical signal (<2%) indicate the homogeneity of the produced tablets. The maximum values of standard deviations of pressed tablets for the selected ranges of elements are much less than acceptable, which confirms the validity of the proposed method of sample preparation. It is also shown that during long-term storage and repeated measurements, pressed tablets with the polyvinyl alcohol solution retain their original structure and intensity of analytical lines of elements. The accuracy of measurements in the subsequent determination of rock-forming elements is consistent with their certified contents. The results obtained can be used to reduce the time spent on getting a representative pressed sample when using polyvinyl alcohol, determining elements without additional support (coating films), microelement and silicate analyzes from one sample.

Magnesium Utilization in Dolomite Rocks by Struvite Precipitation in an Insulated Column Reactor

Dolomite is a natural mineral rock with the chemical formula CaMg(CO3)2. Pure dolomite contains 21.70% calcium and 13.04% magnesium. Dolomite has not been widely used in the industrial sector until now. One way to increase the economic value of dolomite rock is to utilize its magnesium content as a precursor to struvite mineral which is the raw material for slow release fertilizer. Under alkaline conditions, struvite minerals are formed at concentrations of Mg2+, NH4+, and PO43-. Struvite solution (MAP) can be prepared by reacting phosphoric acid, ammonium hydroxide, and dolomite as a magnesium source in a molar ratio of 1:1:1. In a continuously operated isolated column reactor, the pH ranged from 8 to 12, and the reactor inlet air velocity ranged from 0.25 to 1.25 L/min. The chemical elements of dried struvite were determined using XRF (X-Ray Fluorescence), and the morphology was analyzed using SEM (Scanning Electron Microscope). At the same time, the crystal phase composition was identified using the Rietveld XRD (X-Ray Diffraction) technique. Based on the results of XRF analysis, the highest magnesium content was found under operating conditions with pH 12, air rate 0.75 L/min, and magnesium content 15.5%.

Investigation of old waste dump composition of lean gold-bearing ores from the Golden Pride Project (GPP) mining operation in Nzega district, Tanzania

The search for alternative sources of useful minerals is a pressing issue. One such possible source is the processing of lean gold-bearing ores, which previously did not seem feasible to exploit for subsoil users, leading to their disposal in off-balance ore dumps. Processing these resources becomes economically viable as gold prices rise and processing technologies improve over time. This paper presents the elemental and mineralogical composition of lean gold-bearing ore dumps from the Golden Pride Project (GPP) mining operation in Tanzania’s Lihendo district. This area contains an old dump of lean gold-bearing ores, weighing approximately 1.4 million tons. Extracting valuable components from lean mineral raw materials is a current priority. Sampling was conducted to study the dumps. Boreholes were drilled to a depth of 1 m, covering a total sampling area of 20 ha; 18 samples, each averaging 3 kg in weight, were collected. The results of X-ray fluorescence analysis (XRF) indicated the presence of Fe, S, Si, Ca, Ca, Mn, Cu, Al, Cr, Ti, As, and Ag in the collected samples. X-ray diffraction (XRD) analysis revealed that the main minerals in the dumps are muscovite, kaolinite, quartz, montimorillonite, and goethite. The average gold grade in the selected samples is 0.72 g/t. Studies of the grain-size distribution and gold distribution by grain-size classes after ore grinding demonstrated that the majority of gold (74%) is in the −75 μm class. In the initial mineral material of the dumps, the share of the +30-50 mm grain-size class is 81%. The paper proposes potential methods for processing lean dumps of gold-bearing ores. One such methods involves crushing the dump material, separating the −75 μm class, and subjecting it to direct leaching or leaching using “carbon-in-pulp” technique. Heap leaching appears to be the most promising method for extracting gold from such dumps in terms of technical and economic feasibility. Positive experience has been reported in applying this process to ores of similar mineralogical type.

The content of heavy metals in the gray-brown soils of the karakul pasture Karnabchul in Samarkand, Uzbekistan

This article presents the results of X-ray fluorescence analysis (XFA) of gray-brown soils on the content of heavy metals nickel, antimony, copper, zinc, arsenic, lead, vannadium, chromium, manganese, iron, cobalt and aluminum of the karakul pasture Karnabchul. The dynamics of the distribution of heavy metals over the soil profile of graybrown soils is described in graphic images. The drawings depict the landscape of the karakul breeding pasture Karnabchul and the soil section of gray-brown soils.

Влияние катодного внедрения хрома в цинковое покрытие на его защитную способность

The influence of cathodic introduction of chromium into the surface layers of a zinc coating on the change in its corrosion resistance has been determined. Electrodeposition of zinc from electrolytes of various compositions was carried out on electrodes made of St3 steel. TsO grade zinc was used as an anode. Preliminary steel electrode was preparated treating the steel surface of in the potentiostatic mode of pre-phase deposition (DPD) at a potential 50 mV more positive than the equilibrium potential of zinc (Ep) in the working electrolyte for 5 minutes. The zinc coating was applied in potentiostatic mode at a potential of –1.20 V relative to the silver chloride reference electrode. The introduction of chromium into the electrodeposited zinc coating was carried out in the potential range from –0.97 to –1.15 V from electrolytes containing trivalent chromium salt. The results of X-ray fluorescence analysis of the component composition of working electrodes after cathodic introduction of chromium, the morphology of the formed surface obtained using scanning electron microscopy, indicate the presence of chromium in the coating composition and its effect on the structure of the deposit. The corrosion resistance of modified zinc coatings by cathodic introduction of chromium at potentials of –1.05 V and –1.10 V for 5 minutes exceeds this characteristic of chromated zinc.

Денежно-вещевой клад у деревни Асилан (Республика Карелия)

The article is devoted to the publication of the coin-item deposit discovered in 2020 in the North-Western Ladoga region (Republic of Karelia, RF). This is the first discovery of a hoard of silver items in the region over the past 100 years. The article analyzes numismatic items and artifacts of the hoard, presents the results of X-ray fluorescence analysis of the composition of artifact alloys. In total, the hoard included 16 items made of high-grade silver, preserved in the form of whole items and fragments. The numismatic part of the complex is represented by 10 silver coins in the form of Kufic dirhams, their imitations, as well as Western European denarii. The monetary collection of the hoard was probably completed no later than the beginning of the 11 th century. Then the coins continued their existence in the form of jewelry. The overall dating of the items in the hoard makes it possible to attribute its final formation to the 12 th century.

A NEW FIND OF A KUBAN-TYPE HELMET FROM THE NORTHWEST CAUCASUS

The article publishes the discovery of a new cast helmet of the “Kuban type” of the Early Scythian culture. The helmet is considered against the background of other similar cast helmets from the territory of Eastern Europe dating from the 7th–6th centuries BC. The authors discuss an assumption of the origin of East European cast helmets from the prototypes of the Zhou period from Northern China. Special attention is paid to the typological similarity and difference of East European specimens from similar finds from Central and East Asia. The paper proposes a variant for the reconstruction of the technology of mould manufacturing and casting of the product. The authors provide the results of X-ray fluorescence analysis of the metal in the published helmet and compare them with data on other known finds of Kuban type helmets. The comparison shows the difference in the composition of metal which they were made from.

РЕНТГЕНОФЛЮОРЕСЦЕНТНЫЙ АНАЛИЗ ИЗДЕЛИЙ ИЗ ЦВЕТНОГО МЕТАЛЛА ПРЕДТЮРКСКОГО ВРЕМЕНИ, ОБНАРУЖЕННЫХ НА НЕКРОПОЛЕ ЧОБУРАК-I (СЕВЕРНЫЙ АЛТАЙ)

During excavations of burial complexes in Altai, which belong to the Bulan-Koby archaeological culture, items made of non-ferrous metal were found. However, their purposeful study has not yet been undertaken, which limits the possibilities for making the necessary scientific interpretations. This article presents the results of X-ray fluorescence analysis of a small series of finds from the Choburak-I necropolis. This site is located in the Northern Altai and dates back to the preTurkic period. The obtained determinations of the chemical composition of simple decorations demonstrate the variety of recipes used in casting the initial materials. Of particular importance are the items made of brass. The presented variety of metal alloys can testify to wide contacts of the Altai population in the pre-Turkic period, as well as to the existence of local traditions of decoratiions making. It is important to continue the systematic study of similar and other finds from non-ferrous metal, which are in museum collections in Russia and abroad.

Состав сплава металлических предметов из раскопок поселения позднего бронзового века Багай 1 в Северо-Западном Крыму

The Late Bronze Age settlement Bagai 1 is located on the left bank of the Bagai ravine, which flows into one of the largest lakes in the Crimea, Sasyk-Sivash, near the city of Yevpatoria. In the northern part of the settlement, excavations were carried out by the expedition of the Institute of Archeology of the Russian Academy of Sciences in connection with the construction of the Yevpatoria branch of the Tavrida highway. The article examines the results of X-ray fluorescence analysis of the alloy composition of metal finds from the excavations. It turned out that all studied items of the Late Bronze Age were made of tin bronze, in which the corresponding ligature is from 2 to 20 %. The only exception is a miniature chisel, in which there is no tin, and in addition to copper, more than 8 % of iron was found. Other prescription components (arsenic, antimony, lead) are also found in several items, but in very small concentrations (up to 2 %). The use of tin bronze in items of the Late Bronze Age is a distinctive feature of the Central European tradition and allows us to attribute the alloys of the items studied to the Carpatho-Transylvanian metallurgical province.

Formation of functional protective chromium-based coatings by friction cladding

Corrosion damage to metal parts and structures is one of the most important scientific, technical and economic problems. Coatings based on chromium are widely used in modern mechanical engineering. They are used both to solve problems related to the restoration of the size and shape of the surfaces of worn parts, and to improve performance, for example, wear and corrosion resistance, heat resistance, reflective and protective and decorative ability, etc. One of the promising methods for the formation of anti-corrosion coatings is the technology of friction cladding using a flexible tool - a rotating wire metal brush. The article studies coatings formed by friction cladding from donor materials (sintered composites) containing powders of chromium (about 80 %), zinc, copper, tungsten carbide, tungsten-cobalt, hexagonal boron nitride, thermally expanded graphite. The chemical composition of donor materials and the resulting coatings was studied by X-ray diffraction analysis. It was determined that the composition of the obtained coatings based on chromium correlates with the composition of donor materials, however, it additionally contains elements of nickel and iron. It is assumed that iron in the composition of the coating appears as a result of cutting off the particles of the steel base by the bristles of the brush and transferring them to the forming layer of the coating. The nickel content indicates that particles of the wire bristle material of the brush are also introduced into the coating layer. Corrosion tests were carried out in a salt fog chamber KST-2 according to GOST 9.308-85 of samples with coatings obtained by galvanic chromium plating and friction cladding. The coated samples were kept in the chamber for 192 hours. The galvanized coating withstood the test without any signs of corrosion. Traces of corrosion appeared on friction clad coatings, while on all samples the corrosion area was no more than 7 %. It is conditionally accepted that coatings obtained by friction cladding have satisfactory corrosion resistance. The results of X-ray fluorescence analysis of the chemical composition of donor materials and coatings were obtained with the financial support of the Ministry of Science and Higher Education of the Russian Federation (Project No. FZRU-2020-0011). The results of tests for corrosion resistance of samples with applied coatings were obtained with the financial support of the Belarusian Republican Foundation for Basic Research (grant T21ET-005).

IDENTIFICATION OF ROCK CHARACTERISTICS USING XRF, XRD, AND SEM TESTS ON API ALAM IN PAMEKASAN

Research has been conducted into the nature of geothermal rocks in Pamekasan. This place is located in Tlanakan Pamekasan. This study aims to determine the composition of mineral compounds in the soil so that fire can burst out from the soil and the soil does not melt. Three steps can be done with simple refinement and filtering methods, namely X-Ray Fluorescence (XRF), X-ray diffraction (XRD), and Scanning Electron Microscope (SEM). The results of XRF analysis show the element of Api Alam 1 is Ca 66.2%, Api Alam 2 is Si 37.4%, and in hot springs, is Si 39.6%. The XRD results show that mineral qualitatively in Api Alam 1 was in the form of CaCO3 compound at 60.1% and SiO2 at 39.9%, while in Api Alam 2, hot water sources were in the form of SiO2 compound (>90%). SEM Results on Api Alam 1 show that the sample is almost homogeneous (the distribution of CaCO3 and SiO2 is uneven), the presence of slab-shaped clumps that identify the presence of varying grain size, and with high porosity, which indicates that the sample is partially amorphous in structure, in Api Alam 2. The Hot springs show irregular aggregations and poor homogeneity of the sample. The size of the three samples is ten μm or 10.000 nm, while PSA results showed an average size of Api Alam 1 was 509.7 nm, Api Alam 2 was 891.3 nm, and Hot Springs was 468.3 nm.

Дослідження зміни структурного та хімічного складу периклазовуглецевих вогнетривів у процесі експлуатації у складі футерівки кисневих конверторів

The refractory lining plays a crucial role in the performance of modern oxygen converter process, as its durability determines the life of the metallurgical unit. During the campaign, it is subjected to various extreme loads and factors of different nature. The most reliable and widespread methods of establishing the causes of the destruction of refractories are chemical research and structural research of burnt bricks after service in converters. In the work carried out, a study of changes in the lining of a 50-ton oxygen converter was carried out in order to expand the understanding of the influence of technological factors on the macro picture of the destruction of the lining. Thermodynamic analysis confirmed the fact that iron oxides have the greatest influence on lining components, especially in combination with silicon, which has a rather low melting point (1200 oC), which under conditions of elevated melt temperature leads to dissolution and cracking of the refractory working layer. In the zone of the upper cone, a significant influence of magnesium oxidation reactions was established, which is connected with its high affinity to oxygen. For the zone of the metal bath, a significant contribution to the destruction of refractories is made by the oxidation reactions of magnesium and aluminum (as antioxidants in refractories) and their interaction with sulfur, which is due to the greatest affinity of these elements with oxygen and their high activity. In the slag zone reactions of refractory carbon with monooxide of iron, magnesium oxide with magnetite, and interaction of fayalite with carbon and magnesium oxide have great influence. The results of X-ray fluorescence analysis confirm the destruction of refractory products during oxygen conversion as a result of impregnation of the slag melt components into the volume of the refractory, namely due to the interaction of iron and manganese oxides with the carbon-containing bond at elevated temperatures.

X-ray Fluorescence and Laser-Induced Breakdown Spectroscopy Analysis of Li-Rich Minerals in Veins from Argemela Tin Mine, Central Portugal

In this work, X-ray fluorescence (XRF) and Laser-induced breakdown spectroscopy (LIBS) analyses were applied to samples of quartz, montebrasite, and turquoise hydrothermal veins in the Argemela Tin Mine (Central Portugal). Montebrasite (LiAl(PO4)(OH,F)) is potentially the main ore mineral; with its alteration, lithium (Li) can disseminate into other minerals. A hand sample was cut and analyzed by XRF and LIBS for several elements of interest including Cu, P, Al, Si, and Li. Although XRF cannot measure Li, results from its analysis are effective for distinguishing turquoise from montebrasite. LIBS analysis complemented this study, making it possible to conclude that turquoise does not contain any significant Li in its structure. The difference in spot size between the techniques (5 mm vs. 300 µm for XRF and LIBS, respectively) resulted in a poorer performance by XRF in accurately identifying mixed minerals. A thin section was petrographically characterized and mapped using LIBS. The mapping results demonstrate the possibility of the successful identification of minerals and their alterations on a thin section. The results of XRF analysis and LIBS mapping in petrographic sections demonstrate the efficacy of these methods as tools for element and mineral identification, which can be important in exploration and mining phases, complementing more traditional techniques.

РЕСТАВРАЦІЯ ТА ХІМІКО-ТЕХНОЛОГІЧНІ ДОСЛІДЖЕННЯ КАМ’ЯНОЇ СКУЛЬПТУРИ СВ. ЯНА НЕПОМУЦЬКОГО З СЕЛА ЧАБАРІВКА ВАСИЛЬКІВСЬКОГО Р-НУ ТЕРНОПІЛЬСЬКОЇ ОБЛ.

The sculptural composition originates from the village of Chabarivka, Vasylkiv district, Ternopil region (since 2015). On the map of 1779-1783 by Friedrich von Mieg, the sculpture of St. John of Nepomuk is marked with a red cross, located in the eastern part of the village stretched along the road, opposite the manor. The road from Kopychyntsi to Husiatyn passed to the north of the settlement. On the map of the late nineteenth century the figure of St. John of Nepomuk is recorded on the south side of the street, in the eastern part of Chabarivka. Instead, the manor no longer exists, and the existing church does not yet exist. It is probable that in the first half of the 19th century the village community changed the location of the roadside sculptural composition. Since there is a carved coat of arms of Pilava on the stone pedestal of the figure, it is logical to say that the founder of the composition was a representative of the Potocki magnate family. Since the owner of Husiatyn and its environs during 1729-1732 was Stanislav Vladyslav Potocki, we can assume that it was at this time that the sculptural composition of St. John of Nepomuk was made. As a result of thermal studies, it was found that the samples taken from the surface of the figure and the pedestal contain organic surface contaminants. A sample taken from the surface of the pedestal revealed a significant amount of clay contaminants introduced to the surface of the stone by dust deposits. The results of thermal analysis are confirmed by X-ray fluorescence analysis. In the samples taken from the surface layer of the pedestal and the figure, the presence of elements Si, Al, Mg, K, Fe, which are part of the structure of layered silicates, was detected. The relative content of elements present in the structure of clay minerals is determined by the ratio of the areas of the bands of electronic transitions, which are manifested on the spectrum of samples at the corresponding characteristic energies. Based on these data, it can be argued that the surface layer of the pedestal contains more clay contaminants. Based on chemical and technological research, it can be argued that the surface layer of the pedestal contains more clay contaminants than the sculpture. Taking into account the results of historical, art and chemical-technological research, a program of restoration of the monument has been developed: Carrying out a visual and field inspection of the work; Execution of photofixation before completion of restoration works; Study of analogues of the image of St. John of Nepomuk; Execution of mechanical clearing; Extraction of salts from the structure of the stone by applying a compress of cellulose and distilled water; Carrying out of structural strengthening of a stone by the KSE300 Remmers preparation; Production of the lost lower part of a plinth from limestone, its installation on stainless steel cores and epoxy glue; Gluing of the reflected and saved parts to a sculpture on proper places. Gluing the saved left hand with epoxy glue; Making a plasticine model of the saint's head according to the proportions and collected analogues. Execution of a lump plaster form and formation of a head from an artificial stone; Mounting the head using a stainless steel anchor and polyester glue; Gradual addition of lost elements on the sculpture and pedestal with mineral restoration solution with the addition of pigments; Modeling of the neck and collar of St. John of Nepomuk with mineral solution; Execution of structural strengthening of a stone by an alcoholic solution of nanovap; Execution of structural strengthening of a stone by the KSE300 Remmers preparation; Coating the monument with a long-acting biocidal solution from Remmers; Double plastering of the monument with a solution of historical translucent azure and water water repellent by Remmers with the addition of pigments for stone tinting; Execution of final photofixation of a monument after the carried-out restoration actions. Chemical-technological studies confirm what was revealed by visual examination and microscope. During the restoration, a full range of measures was taken to stabilize the material structure of the sculptural composition. Remains of blue and red paints were found during the work. According to the results of X-ray fluorescence analysis, it was found that the staining was done in the XIX century. Instead, the primary staining was not detected. The performed chemical-technological researches have formulated a restoration map, will allow in the following works to define more precisely mineral composition of a stone and the author's color decision of a work of art. After the completion of the restoration works, the sculptural composition acquired artistic integrity and received a sacred meaning. Similar works of art located on the territory of Ukraine need to be preserved and restored, as they form a valuable cultural landscape of historical settlements.

Случайные находки артефактов из Чарышского района Алтайского края

The paper is devoted to the generalization and characterization of random finds from the territory of the Charyshsky district of the Altai Territory. The summary includes both previously published items and new artifacts, information about which was received by the authors during the archaeological research of the Ust-Teplaya burial ground in 2020. The collection of artifacts published for the first time consists of three items. This is a double-headed iron psalium with sculptural design of the tips in the form of the heads of mythical birds with an elongated beak, a horn double-headed psalium and a bronze knife with a ring pommel. These items supplement the body of random finds from the area under consideration, which includes items already published in the scientific literature, such as stone drilled axes belonging to the Afanasyevo culture of the Eneolithic era of the 31st — 27th centuries BC, stone mace pommel and bronze dagger of the early and Middle Bronze period of the 22nd — 15th centuries BC and bronze bits of the Early Scythian time of the 8th — 6th centuries BC. The paper also presents the results of X-ray fluorescence analysis of a metal knife and bit, which showed that the objects were cast from a copper-tin alloy. The analyzed artifacts, random finds from the territory of the Charyshsky district of the Altai Territory, reflect various historical and cultural stages of the development of the population of Northern Altai. The artifacts add to the collection of archaeological sources on the ancient history of the region, from the Eneolithic to the early Middle Ages inclusively. Keywords: random finds, artifacts, psalia, bits, knife and dagger, mace pommel, stone axes, Eneolithic, Afanasiev culture, Bronze Age, Early Iron Age, Early Scythian time, Pazyryk culture, Early Middle Ages

Монетные сплавы Херсонеса Таврического периода независимости

This paper presents the results of X-ray fluorescence analysis of the composition of alloys of the two largest collections of coins of ancient Chersonese residing in the State Historical and Archaeological Museum Preserve of Tauric Chersonese and the Yevpatoria Regional Museum. In total, about a thousand coins studied, which, together with the 400 coins previously examined from the State Hermitage Museum, constitutes a solid basis for conclusions. The given paper analyses the data obtained for coins of Chersonese in the Period of Independence, that is from the emergence of local coinage in the early fourth century BC to the wars of Diophantos in the late second century BC. For the first time it has been determined that big dichalkoi were minted from a special coin alloy, two-component high-tin bronze, in the period of economic prosperity of Chersonese in the second half of the fourth and third centuries BC. These coins served as the financial basis for important transformations in the near and distant chora: the land division system of vineyards and territorial expansion of Chersonese into the north-western Taurica. Only in the third century BC, in the period of an unprecedented consolidation of land properties and the transformation of the wine production into a commodity industry, the minting of large silver coins of full metal value began probably for big financial deals and payments in international trade. The crisis in the minting of Chersonese in the late second century BC touched silver drachmae, the overwhelming majority of which were minted from a low-grade silver alloy with the copper comprising more than a third of the composition. Thus, full-weight coins turned to conditional money.

МАЛОВІДОМИЙ ТИП НАСЛІДУВАННЯ ДИРХЕМА З «КНЯЗІВСЬКИМ ЗНАКОМ» ВОЛОДИМИРА ОЛЬГЕРДОВИЧА

Мета статті полягає у введенні до наукового обігу, нумізматичному дослідженні та атрибуції донедавна невідомого типу місцевих наслідувань дирхемів хана Токтамиша (1380–1399) карбування київського князя Володимира Ольгердовича (1362–1394). Автор розглядає обставини та географію знахідок, аналізує результати їх метрологічного дослідження, порушує питання про емітента, причини випуску цього типу наслідування, період карбування, специфіку обігу, пропонує власну версію атрибуції «князівського знаку» на аверсі монет. Методологія дослідження окреслена принципами науковості, історизму, об’єктивності, методами аналізу, класифікації, узагальнення, історико-генетичним та історико-типологічним, методом штемпельного аналізу. Наукова новизна. Імовірним прототипом для наслідування міг бути дирхем хана Токтамиша карбування Сарая ал-Джадіда з датою 794. Пов’язати досліджувану емісію з іменем Володимира Ольгердовича дозволяє стилістична тотожність «князівського знаку» на аверсі монет із геральдичним елементом денаріїв цього князя. Присутня на монеті дата та історичні обставини зміщення Володимира з київського удільного столу дозволяють окреслити період карбування цього типу монет 1392–1394 рр. Відомі на сьогодні знахідки дирхемів з «князівським знаком» локалізовано дугою вздовж лінії литовсько-татарського прикордоння в межах південних і східних теренів Київського удільного князівства та сусідніх північних територій Сіверщини. Головною метою емісії вважаємо економічні мотиви, а саме покриття дефіциту монетної маси на грошовому ринку прикордоння в межах Київського князівства. Участь даної емісії в торгівельних чи данницьких розрахунках з Ордою наразі недостатньо підтверджується нумізматичними джерелами, проте останнє не заперечує можливості спорадичного проникнення цих монет внаслідок переважно роздрібних торгово-грошових операцій на широкий простір литовсько-ординського прикордоння. Припускаємо, що однією з причин карбування Володимиром Ольгердовичем наслідувань даного типу могло бути спровоковане складними військово-політичними реаліями прагнення князя до ширшої політичної автономії й перегляду в майбутньому свого політичного статусу. Авторські спостереження дозволяють припустити стилістичний зв’язок «князівського знаку» на монетах із родовими гербами київських князів Х–ХІ ст. Чітка просторова орієнтація цього геральдичного елементу на наслідуваннях дирхема спонукає до перегляду усталеної в нумізматиці думки щодо просторової орієнтації «князівського знаку» на київських денаріях Володимира Ольгердовича. Висновки. Попередня атрибуція нумізматичної пам’ятки дає підстави стверджувати, що ми маємо справу з новим і наразі малодослідженим у нумізматиці типом наслідування дирхем хана Токтамиша карбування київського князя Володимира Ольгердовича (1362–1394). Присутність на атрибутованій монеті «князівського знаку» може свідчити про офіційний характер емісії та її приналежність до регіональних регулярних наслідувань джучидських монет.

Calibration Standard Samples for Multielement Analysis of Silicate Rocks Using Inductively Coupled Plasma Mass Spectrometry with Laser Ablation

A comparison of different standard samples—artificial glass SRM-612 (Standard Reference Material) and standard samples of natural composition SG-1A, SG-3, ST-1A, and SGD-1A—used for external calibration in the elemental analysis of silicate rocks in the form of fused glasses by inductively coupled plasma mass spectrometry and laser ablation (LA-ICP-MS) is carried out with a goal of selecting the most suitable samples for plotting the calibration dependence upon determination of the major and trace elements when using LA-ICP-MS for routine analysis. The results showed that the error of determination for both major and trace elements is lower (compared to SRM-612) when external calibration is carried out using the reference materials of natural composition with Si and Fe contents close to those in the analyzed samples. The use of internal standards in both cases decreases the systematic error attributed to the drift of LA parameters and different ablation yields. The correctness of the determination of 28 elements is proved in comparison of the results of the analysis of four standard samples with the reference values. The obtained results are used to select calibration standards for LA-ICP-MS analysis of the samples of unknown composition. The results of analysis of six samples of unknown composition match within the error limit the results of X-ray fluorescence analysis (major elements) and ICP-MS (trace elements in solutions). Refining of the content of trace elements in the previously certified reference materials allows them to be used for calibration in routine analysis of geological rocks. The developed LA-ICP-MS technique is a rapid method for determination of a wide range of elements, in particular, rare earth elements, in silicate rocks and can be used for routine analysis without additional sample preparation after X-ray fluorescence analysis.

Year over year comparison of sediment quality in the rivers of Eastern Slovakia

Quality is one of the most important risk indicators in river basins. Therefore, monitoring and evaluating water and sediment quality has a very important role in process of risk management. The aim of the monitoring is provide for the sustainability of water bodies and these results are the basis for the risk management in the river catchment area. Hornad, Laborec and Poprad are the rivers in Eastern Slovakia. Hornad and Laborec belongs to basin of Danube and Poprad belongs to basin of Vistula. Sediment sampling was carried out according to ISO 5667-6. Monitoring was carried out in the spring on 2017–2018. The chemical composition of sediments was determined by means of X-ray fluorescence (XRF) using SPECTRO iQ II (Ametek, Germany, 2000). The results of sediment quality evaluated by method PERI revealed that the quality of sediment in 2018 was better than 2017. Results of XRF analysis of sediments were compared with the limited values according to the Slovak Act 188/2003 Coll. of Laws on the application of treated sludge and bottom sediments to fields. It can be state that limit values comparing with Slovak legislation were not exceeding in all sediment samples in rivers in Eastern Slovakia. Based on the monitoring data of sediment quality in the study area, a quantitative analysis of heavy-metal pollution in sediment was conducted using the method of potential ecological risk index (PERI) which is method for evaluate the potential ecological risk of heavy metals. It is based exclusively on chemical parameters of sediments because sediment data show mean integrated values in time, with higher stability than water column parameters; sediments are easily sampled at field work; sediment samples are more representative for time and space scales and analytical data are easily obtained, especially because sediments present high concentrations of contaminants, decreasing the possible errors due to detection limits of the applied analytical method. This method comprehensively considers the synergy, toxic level, concentration of the heavy metals and ecological sensitivity of heavy metals. Potential ecological risk index can be obtained using three basic modules: degree of contamination (CD), toxic-response factor (TR) and potential ecological risk factor (ER). The results show on the basis on potential ecological risk index that the quality of sediment in 2018 is better than 2017. The worst result shows Hornad in 2017. Significant improvement occurred at the sampling point S2 in Hornad in 2018. The best results show Laborec in 2018. The results show on the basis on potential ecological risk index that quality of sediment in 2018 is better than 2017.

Silver and silvery alloys in Early Minoan IB Crete

ABSTRACT This paper presents the results of X-ray fluorescence analysis carried out in the last years on silver objects from three different Cretan Early Minoan cemeteries, Hagia Photia Siteias, Kephala Petras, and Livari Skiadi, dated to ca. 3000 to 2800 BC. The classes of objects discussed in this paper comprise mainly daggers and jewelry pieces; other kinds of items, however, can also be included as comparisons. For this project various groups of copper-alloy and silver-alloy artifacts from Hagia Photia, from the Petras rock shelter, and from Livari have been analyzed. The silver-based objects of this period can be distributed into two groups according to their composition: unalloyed silver and alloys of silver and copper or silver and arsenical copper. The analyses of the metal finds, both of silver and of arsenical copper, from the three sites indicate their appurtenance to the same metallurgical tradition, common to the areas around the Black Sea, Anatolia, and the Near East, with similar metallurgical practice, esthetic choices, and styles.