bluuebunny/crossref_metadata_2025 huggingface dataset:
Fault Analysis and Reduction of Harmonics of Three-Level Three Wire and Four-Wire Neutral Point Clamped Inverter using PWM Switching Technique
Authors: Mohsin Muhammad Yasin , Tahir Sohaib , Tahir Waqar , Farid Ghulam , Watoo Waqas Ahmad , Haris Muhammad
Published: December 2023

Energy generation through wind and solar is increasing with the rising interest in the renewable and clean form of energy. Due to energy crises, the world is shifting from nonrenewable energy resources to renewable energy resources. Renewable energy resources are the green and eco-friendly sources and do not affect the climate like the other fossil fuels. Renewable fuels gain popularity due to their sustainability and low carbon emission. To get energy from renewable energy sources, well-defined mechanisms and control devices must be needed. Therefore, the reliability and stability of the system are required. The inverter is one of the tools which have a significant contribution to controlling the operation of the energy conversion system. The inverter is an accessory that changes a Direct Current (DC) source into an Alternative (AC) source. By using that AC source, we can easily derive AC appliances and drive the loads. To gain more power or to derive large power motors whose power ratings are up to several kilo/Megawatts, we need multi-level inverters. One of the types of multi-level inverters is the Neutral Point Clamped inverter (NPC). NPC inverters are used where considerable power is required, such as of several megawatts. The main contribution of this research paper is to design the three levels of neutral point clamped inverters by using the Pulse width Modulation (PWM) and Space Vector Modulation (SVM) Techniques.
Sentiment Base Emotions Classification of Celebrity Tweets by Using R Language
Authors: Mehboob Sumaira , Zaidi Syed Ali Jafar , Rizwan Muhammad , Dilshad Usman , Lashari Nadeem , Adeel Mian , Sanwal Ghulam Hassan
Published: December 2023

Twitter is considered as one of the most effective microblogging site(s) developed mainly to express the views and thoughts of its users. Twitter users follow their favourite personalities, i.e., celebrities, and use to tweet/retweet, frequently, without knowing the emotions behind the made tweet. This research focuses on learning the emotions behind the tweets using R language by formulating it as an emotion classification problem. We applied twitter scraper data scraping technique to collect the dataset from the twitter accounts for our analysis. By using the proposed scheme, we estimate the emotions (whether the person was happy, sad, anxious, joyous, angry, surprised or feared) behind the tweet. We believe that our scheme would help users understand more the personality insights from the tweets. Sentiment R Package of R programming language is used to find out the personality insight than the positive, negative and neutral emoticon combined to find out the accurate results. If the user has more negative tweets we can say that he is happy and joys or if the negative tweets are more than positive tweets we can quickly evaluate that the personality is sad, angry, anxious or feared. The main contribution of this paper is to identify the emotions and the trend of the characters or twitter users.
Probability Distribution of Transient Response of an Electric Circuit
Authors: Farooq-i-Azam Muhammad , Siddiq Asif , Iqbal Muhammad Usman
Published: December 2023

In this work, we explore the transient response of an electric circuit using probabilistic analysis when the precise value of the characteristic parameter of a circuit element is not known and is instead constrained to a range of values. To accomplish this, a combination of probability theory and traditional circuit analysis techniques is employed. In this approach, the circuit element’s parameter is treated as a random variable, and probability methods are used to derive the probability distribution of the voltage or current across it. To demonstrate this approach, we apply it to a resistor capacitor (RC) circuit, where the capacitance parameter of the capacitor is regarded as a random variable. We derive probability distributions for the transient voltage across the capacitor and the voltage at the output terminals to illustrate the method’s effectiveness.
Optimum Model for Tracking of Moving Objects
Authors: Hussain Muzaffar , Farhi Lubna , Rehman Farhan Ur
Published: December 2023

In wireless communication, it is a challenge to find the accurate position of moving objects. The presented work proposes the GPS receiver to measure the position and velocity of moving objects. These measurements are dynamic, the Least Squares (LS) technique is used to linearize the measurement for further processing. Afterward, the time difference of arrival (TDOA) mythology is applied. The obtained data is then processed through a Kalman filter to mitigate non-line-of-sight errors and smoothen the range values. The Kalman filter applies standard deviation on received data and performs an NLOS/LOS hypothesis test. By processing the received data, the algorithm generates readings that mitigate the NLOS error and reduces position error. The simulations demonstrate that the proposed algorithm reduced the noise by 28.64% and 34.4% in LOS and NLOS regions respectively. These findings indicate that the accuracy of object tracking was significantly improved as compared to other algorithms while also being less computationally intensive and cost efficient.
Analysis of Device-to-Device Communication in IoT System
Authors: Nawaz Usman , Rehman Faisal , Azmat Ullah Kainat , Ahmed Raza Usman , Sharif Hanan , Iqbal Muhammad Junaid
Published: December 2023

Peer-to-Peer communication is based on an important feature of communication which is Device-to-Device (D2D) communication. IoT is a computational device that is equipped with accurate identifiers and the capacity to speak data across a network without the assistance of a human. D2D communication is referred to as “Direct verbal exchange among the taking part gadgets without the use of the centralized infrastructure”. This research study examines the advantages and barriers of D2D communication as a means of meeting the IoT's requirements. Many companies and quality management organizations have demonstrated a strong interest in implementing the D2D approach in wireless networks. The thought of working without the necessary control of centralized supervision and making Wi-Fi networks wider as well as energy saving can be made possible with D2D communication in IoT. These devices' technical limitations and the connection's support limitations provide an upward push to numerous problems that must be addressed. Some of the IoT studies Electricity production, connectivity, security, scenario technologies, and so forth are all issues. We cognizance’s on troubles that in the IoT there is an influence in D2D communication surroundings. We also discovered some important stumbling blocks to the success of smart D2D speech communication in the Internet of Things. We talked about how to deal with these difficult situations. This research explains the idea of a tool to tool verbal exchange and IoT system and defines its predominant techniques and applications imparting a subsequent era therefore as procedure strategy to the demanding situations. To boost research and development in the domains IoT problems have been studied. Every cited research work's contribution and limitations are discussed as well as any potential problem statement and open rely.
Choosing Banks’ Profitability Predictors: A Comparison of Logistic Regression and Discriminant Analyses
Authors: Khan Saadut Ullah , Iqbal Zahid
Published: December 2023

For researchers, banks' profitability has been a key factor. Various internal and external factors may have an impact on the banks’ profitability. Internal factors are unique to each bank and have an impact on management decisions that affect bank profitability. External factors are those outside of the banks' control that can affect how well they perform. This study examines significant financial variables identifying profitability perspectives and two predictive models of banks’ profitability using the banks' data from the period of 2007-2016. Logistic regression and discriminant analyses were used and evaluated their predictive accuracy. Although, logistic regression and discriminant analysis are unusual for such studies as the dependent variable is continuous and these techniques are applicable when the dependent variables are categorical. So, in order to convert the dependent variable i.e. return on assets to binary variable, ’1’ is assigned for a positive return on assets and ‘0’ for a negative return on assets. The empirical results described that there is a statistical difference between the prediction results of logistic and discriminant analyses. The discriminant models identified that non-interest income, interest rate, operating efficiency, and bank size have a significant effect on banks’ profitability. On the other hand logistic regression showed there are two significant factors i.e. interest ratio and bank size. In the comparison of the models and the accuracy rate of discriminant analysis is higher than that of logistic regression
Graphical User Interface-Based Detection of Kidney Stones Using Image Segmentation Techniques
Authors: Shah Khadijah Ali , Mushtaq Zohaib , Hussain Syed Muddasir , Aziz Muhammad Haris
Published: December 2023

The exponential increase in detrimental surroundings and unhealthy nourishments is causing various health issues in humans. The most destructive effect of such lifestyles is on the kidneys, which cause many kidney diseases, and the most common among them are kidney stones. Kidney stones are a regular but life-threatening disease as they mostly remain unrecognized at the initial stages, leading to an increased threat of end-stage kidney failure. Due to the high recurring rate, Medical Imaging technologies are of paramount importance in detecting this serious public health threat worldwide. This research paper provides a Graphical User Interface for the detection of kidney stones that enables ease of understanding and point-and-click control of the algorithm in MATLAB. The proposed work uses CT scan images to explore image processing techniques due to their reliability and regularity. The algorithm enhances kidney stone screening by improving image quality and focusing on the region of interest. This study highlights the best solutions of imaging techniques to resolve problems like grainy pixels, low-resolution images, and the inaccurate detection of kidney stones due to size and resemblance with nearby parts. All this begins with examining the medical imaging slices from the body area, which later undergoes preprocessing, segmentation, and boundary detection techniques. To check the accuracy of the algorithm, 12 features were extracted using GLCM. Finally, the obtained features were classified using the Classification Designer App in MATLAB. An accuracy of 99.2% was acquired using Ensemble Classifiers. Also, for further progress in the detection of kidney stones in the future, an AI model can be trained so that it can deal with images having different thresholds for better management of the disease.
To Control the Speed of a DC Motor Using a Specially Designed PID Algorithm
Authors: Ahmad Haseeb , Zubair Abdullah
Published: December 2023

This work presents the design and implementation of a circuit that uses a proportional, integral, and derivative (PID) controller to control the revolutions per minute (RPM) of the direct current (DC) motor in real time that uses a microcontroller platform. The algorithm used in the microcontroller was the algebraic equations of the general PID controller equation. The paper discusses the structure of a PID algorithm and its implementation. From the algebraic equations, the error, cumulative error, and delta error of the PID controller have been found. The designed algorithm is implemented using the Arduino software (IDE). The aim of this work is to control the speed (RPM) of the DC motor using the PID design technique. The designed control system circuit is affordable. The system is tested in real-time, steady-state error, and response time is inspected successfully. The designed circuit is tested for various speed inputs satisfactorily. The speed control using PI and PID control methodology is described.
A Review of Real-Time Monitoring of Hybrid Energy Systems by Using Artificial Intelligence and IoT
Authors: Nishtar Zuhaib , Afzal Jamil
Published: December 2023

This research focuses on the invention of real-time monitoring of hybrid energy systems using artificial intelligence (AI) and the Internet of Things (IoT). The study aims to develop a monitoring system that provides real-time insights, anomaly detection, fault diagnosis, and energy optimization. The research methodology involves the integration of AI algorithms and IoT devices to collect, analyze, and visualize system data. The results demonstrate the effectiveness of the developed monitoring system in improving system performance, sustainability, and cost savings. The practical implementation and scalability of the system are also addressed, along with future research opportunities. This research contributes to the advancement of monitoring systems for hybrid energy applications, promoting efficiency and sustainability in energy management. This research provides significant contributions to the field of real-time monitoring of hybrid energy systems. The article focuses on addressing key problems related to the real-time monitoring of hybrid energy systems using AI and IoT technologies. The lack of real-time insights provided by conventional methods also limits timely decision-making and responsiveness to dynamic changes in the system.
A review on the current status of homoeopathy in the management of schizophrenia
Authors: Kudukayil Sreeja Kudukayil Radhakrishnan Nair
Published: December 2023

Background: Schizophrenia is a mental condition not only affecting routine of daily of life but also the Quality of life with devastating consequences for affected individuals and their families.Objectives: This review aims to detect the current status of homoeopathy in the management of schizophrenia. Materials and Method: a search is done in search engines of Google scholar, PubMed and Cochrane, CINAHL PsycINFO, Hom-Inform. Identified articles of homoeopathy in schizophrenia is collected and summarised in this review. Result: Though there is scarcity in studies, the available data shows scope for future research in homoeopathy in schizophrenia.
A clustering-based method for identifying and tracking squall line
Authors: Shi Zhao , Wen Yuxiang , He Jianxing
Published: December 2023

Abstract. The squall line is a type of convective system characterized by storm cells arranged in a line or band pattern, which is usually associated with disastrous weather. The identification and tracking of squall lines plays an important role in early warning of meteorological disasters. Based on weather radar data, a clustering-based identifying and tracking algorithm for squall lines is presented. Clustering analysis is designed to distinguish the strong echo area and estimate the feature value including reflectivity value, length, width, area, endpoints, central axes, and centroid. The clusters in the linearly arranged form are merged to improve the identification ability in the development stage of squall lines. The three-dimensional structure and movement tracking of the squall line are obtained using the centroid and velocity of the squall lines identified in a single layer. It is demonstrated that the method can effectively identify and track one or more squall lines over a weather radar scanning area. The result shows that the recognition accuracy rate in the single scan elevation of this method is 95.06 %, as well as a false positive rate of 3.17 %. This method improves the accuracy of squall line identification in the development stage of squall lines and works relatively efficiently even when high interference contaminates.
Response patterns of moss to atmospheric nitrogen deposition and nitrogen saturation in an urban-agro-forest transition
Authors: Deng Ouping , Chen Yuanyuan , Zhao Jingze , Li Xi , Zhou Wei , Lan Ting , Ou Dinghua , Zhang Yanyan , Liu Jiang , Luo Ling , He Yueqiang , Yang Hanqing , Huang Rong
Published: December 2023

Abstract. Increasing trends of atmospheric nitrogen (N) deposition resulting from a large number of anthropogenic emissions of reactive N are dramatically altering the global biogeochemical cycle of N. Nitrogen uptake by mosses mainly from the atmosphere, making it a competent bio-indicator for N deposition. However, high uncertainties exist when using mosses to indicate N deposition, especially in choosing sampling period and sampling frequency. In this study, atmospheric N deposition and moss N content in the urban-agro-forest transition, a region with a high N deposition level of 27.46~43.70 kg N hm-2 yr-1, were monitored, and the method for atmospheric N deposition monitoring by mosses was optimized. We found that the optimal sampling frequency is within six months per time, and the optimal sampling time is autumn (October and November) and summer (July and August), which gives us a better estimation for atmospheric N deposition than other scenarios. In addition, the moss N content could better indicate total N deposition than the deposition of specific N species. This study eventually allowed moss to be used more effectively and sensibly as an indicator of atmospheric N deposition and helped to improve the accuracy of the model of quantifying N deposition by using mosses.
Dissolved Nitric Oxide in the Lower Elbe Estuary and the Hamburg Port Area
Authors: Ingeniero Riel Carlo O. , Schulz Gesa , Bange Hermann W.
Published: December 2023

Abstract. Nitric oxide (NO) is an intermediate of various microbial nitrogen cycle processes and the open ocean and coastal areas are generally a source of NO in the atmosphere. However, our knowledge about its distribution and the main production processes in coastal areas and estuaries is rudimentary at best. To this end, dissolved NO concentrations were measured for the first time in surface waters along the lower Elbe Estuary and Hamburg Port area in July 2021. The discrete surface water samples were analyzed using a chemiluminescence detection method. The NO concentrations ranged from below the limit of detection (9.1 × 10−12 mol L−1) to 17.7 × 10−12 mol L−1, averaging at 12.5 × 10−12 mol L−1 and were supersaturated in the surface layer of both the lower Elbe Estuary and the Hamburg Port area, indicating that the study site was a source of NO to the atmosphere during the study period. On the basis of a comprehensive comparison of NO concentrations with parallel nutrient, oxygen, and nitrous oxide concentration measurements, we conclude that the observed distribution of dissolved NO was most likely resulting from microbial nitrogen transformation processes, particularly nitrification in the coastal-brackish and limnic zones of the lower Elbe Estuary and nitrifier-denitrification in the Hamburg Port area.
Multiscale modeling approach to assess the impact of antibiotic treatment for COVID-19 on MRSA transmission and alternative immunotherapy treatment options
Authors: Faniran Taye , Adewole Matthew Olayiwola , Chirouze Catherine , Perasso Antoine , Eftimie Raluca
Published: December 2023

Methicillin-Resistant Staphylococcus Aureus (MRSA) infection can occur alongside or following COVID-19, which is a concern in healthcare settings. The effectiveness of antiviral treatments for COVID-19 depends on a functioning immune response, but antibiotics used for bacterial infections like MRSA can disrupt the immune response and reduce the effectiveness of antiviral treatments. The emergence of MRSA due to excessive antibiotic usage has led to the widespread use of vancomycin as an alternative treatment. Immunomodulatory antibiotics like azithromycin may also be considered. To study the dynamics of these coinfections, a multiscale model was developed. Parameter estimation and sensitivity analysis were performed, revealing influential parameters affecting the reproduction number. Numerical simulations showed that methicillin may increase the population of co-infected cells, while azithromycin can improve the host immune response but has limited impact on MRSA proliferation. Increased efficacy of vancomycin can lead to MRSA eradication. Combination of immunomodulatory antibiotics and vancomycin has minimal effect on co-infected cell population, but increased vancomycin efficacy can reduce coinfection severity. This study emphasizes the importance of continuous research, surveillance, and the development of effective strategies to combat the complexities of COVID-19 and MRSA coinfection.
Adam Opatowski (1574-1647). W 300-letnią rocznicę śmierci
Authors: Bracha Franciszek
Published: December 2023

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Stanisław Wieczorkowski, Z historii Uniwersytetu Jagiellońskiego w pierwszej połowie XVII w.
Authors: Usowicz Aleksander
Published: December 2023

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Nauka teologii moralnej w dawnych seminariach misjonarskich
Authors: Wicher Władysław
Published: December 2023

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Rzekoma rozwiązłość Judyty Salickiej, drugiej żony Włodzisława Hermana
Authors: Umiński Józef
Published: December 2023

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Metryka promowanych Wydziału Teologicznego Uniwersytetu Krakowskiego z lat 1639-1741
Authors: Barycz Henryk
Published: December 2023

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Ks. Franciszek Śmidoda CM (1902-1944)
Authors: Schletz Alfons
Published: December 2023

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Stan badań nad dziejami mistyki w Polsce
Authors: Górski Karol
Published: December 2023

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Pasja chorałowa w Polsce
Authors: Poźniak Włodzimierz
Published: December 2023

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Arcybiskup J. D. Solikowski obrońca naszych praw morskich w XVI wieku
Authors: Zalewski Jan
Published: December 2023

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S. Anna Lubańska, pierwsza albertynka (1844-1913). Przyczynek do historii Zgromadzenia SS. Albertynek
Authors: Stelmach Ambrozja
Published: December 2023

W 1961 roku minęło siedemdziesiąt lat od chwili, gdy pierwsze Siostry Posługujące Ubogim, zwane popularnie albertynkami, ukazały się na ulicach Krakowa. Do pierwszych, które miały odwagę wplątać się w tę nadprzyrodzoną awanturę życiową należały: Anna Lubańska, Maria Silukowska, Maria Maksymiuk, Marta Kuszewska, Maria Niewiadomska, Franciszka Gołębiowska i Teresa Szucka. W niniejszym artykule autorka pragnie przybliżyć postać Anny Lubańskiej, pierwszej albertynki.
Życie religijne w Wojniczu do połowy XV w.
Authors: Szymański Józef
Published: December 2023

Niniejsze studium jest próbą odtworzenia socjologicznego obrazu grupy społecznej, jaką niewątpliwie jest parafia. Skupiono się w nim na analizie życia religijnego w Wojniczu do I połowy XV wieku. Autor starał się podkreślić te cechy historyczne, które decydowały, że oblicze religijne parafii było takie a nie inne. Choć w zasadniczych swych zrębach studium pozostaje historycznym, nie ma pretensji do uchwycenia wszystkich cech, które należało by może podkreślić lub nawet szerzej potraktować.
Autobiograficzne zapiski M. Barbary od Najśw. Sakramentu, karmelitanki bosej (1670)
Authors: Górski Karol
Published: December 2023

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Życiorys świątobliwego kleryka Antoniego Willicha (1739-1759)
Authors: Schletz Alfons
Published: December 2023

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Rec.: Ludomir Bieńkowski, Działalność organizacyjna biskupa Jana Biskupca w diecezji chełmskiej (1417-1452), "Roczniki Humanistyczne" t. 7: 1960
Authors: Stamirski Henryk
Published: December 2023

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Wydania i przekłady dzieł kardynała Hozjusza we Francji
Authors: Jobert Ambroise
Published: December 2023

Przedmiotem niniejszego studium jest próba przedstawienia i przybliżeniu szerszemu ogółowi dzieł kardynała Stanisława Hozjusza drukowanych we Francji. Autor w wyniku szeroko zakrojonej kwerendy doszedł do wniosku, że wszystkie dzieła Hozjusza były drukowane w języku łacińskim lub w tłumaczeniu na język francuski. Niewątpliwie przed Adamem Mickiewiczem właśnie dzieła Hozjusza były najbardziej znane i  czytane wśród francuskich czytelników.
Kraków benedyktyński w XI w.
Authors: Tobiasz Mieczysław
Published: December 2023

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Pegmatites from western Rhodope Mts.: zircon data
Authors: Grozdev Valentin , Vassileva Rossitsa D. , Georgieva Sylvina
Published: December 2023

Ages of pegmatites from two localities (Rakitovo, Lepenitsa) from the western Rhodope Mts. were acquired by U-Pb geochronology on zircon with LA-ICP-MS. The pegmatites are hosted by the metamorphic rocks of the Chepino lithotectonic unit. The large pegmatite/s accumulation from the “Suhata Reka” quarry (Rakitovo locality) is formed at 68.7±1.3 Ma, while small deformed body southwards of Velingrad town (Lepenitsa locality) yielded age of 63.4±1.2 Ma. Crosscutting altered andesite dyke is presumed to intrude the metamorphic rocks and pegmatite at 59 Ma in the Lepenitsa locality. The data suggests connection with the initial stage of the magmatic activity of the Rila-West-Rhodope Batholith (RWRB).
REE distribution in sequential leached phases from deep-sea polymetallic nodules and sediments
Authors: Hikov Atanas , Milakovska Zlatka , Lyubomirova Valentina , Lihareva Nadezhda
Published: December 2023

The distribution of main elements and REE in sequential leached phases from deep-sea polymetallic nodules and sediments from the eastern part of the Clarion-Clipperton fractures zone, NE Pacific are studied. Results show extraction of Mn in the leach 2 in both nodules and sediments. The extraction of Fe, P and REE is different for leach 2, 3 and residual fraction for nodules and sediments. Phosphorous and REE have strong positive correlation which suggests that the phosphate component is the main important carrier of REE in both nodules and sediments but Fe-Mn oxyhydroxides and clay minerals cannot be excluded as carriers of REE.
Trace element geochemistry of altered pyroclastic deposits from the Eastern Rhodopes (SE Bulgaria)
Authors: Ivanova Rositsa , Dimitrova Dimitrina , Sergeeva Ivanina , Yossifova Mariana , Vlahov Alexander
Published: December 2023

The contents of major and rare elements in 10 samples of altered (mainly zeolitized) pyroclastic rocks from the Eastern Rhodopes are investigated. The samples are selected to represent different secondary mineral associations specific to the area. The obtained results indicate that the diversity in secondary mineral associations has relatively little influence on the trace element geochemistry of zeolitized pyroclastic rocks in the Eastern Rhodopes. Regarding their trace and rare earth element composition, these rocks show the main characteristics seen in the acid lavas in the area.
Geotribometamorphism in seismic zones of the Earth’s crust
Authors: Kozhoukharova Evgenia
Published: December 2023

Geotribometamorphism means a process of destructive-constructive changes of the rocks in the seismotectonic zones in the Earth’s crust. Due to the friction between rock blocks and layers, kinetic energy is generated, which deforms and destroys the rocks until mylonitization and melting in an environment of high temperature and pressure. Subsequently, the disintegrated material recrystallized into new high-pressure rocks such as eclogites, garnet lherzolites, phengite and kyanite schists and calciphyres. These rocks mark paleoseismic zones and events that occurred during the Precambrian and Phanerozoic.
40Ar/39Ar and U-Pb age correlations of the large Rupelian Rhodope Massif eruptions with airfall tuffs in SE, S and Central Europe
Authors: Marchev Peter , Raicheva Raya , Filipov Petyo , Jicha Brian , Spikings Richard , Ivanova Rositsa , Bachmann Olivier , Guillong Marcel , Okay Aral
Published: December 2023

Numerous Eocene and Oligocene volcanic tuff layers within the Eastern, Central and Southern Europe sedimentary basins attest to extensive volcanic activity. Tephra dispersal of these tuffs covers areas of more than 1 000 000 km2, and the volume of erupted material to 1000s of cubic kilometers. The sources of the eruptions, however, remain unknown. Using precise 40Ar/39Ar and U-Pb radiometric dating, we correlate some of these tuff layers to three silicic Rhodope Massif Rupelian (еarly Oligocene) supereruptions dated at 33.2 Ma, 32.8 Ma and 31.6 Ma and named Dazhdovnitsa, Borovitsa and Perelik. Hence, these tuff layers can now be used as regional stratigraphic isochronous marker horizons for correlating, dating and synchronizing deposits and events in geologic and paleoenvironmental studies.
Petrology of the 31.6 Ma Central Rhodope Perelik monotonous intermediate ignimbrite eruption
Authors: Marchev Peter , Raicheva Raya , Filipov Petyo , Ivanova Rositsa , Baziotis Ioannis
Published: December 2023

Volcanism during the Priabonian–Oligocene times (35–27 Ma) in the Rhodope Massif produced large volume of shoshonitic and calcalkaline lavas and three large volume silicic ignimbrites and fallout deposits. The youngest of these ignimbrites, named here as Perelik ignimbrite (PI), consists of three areas, previously described as three separate ignimbrite units, namely Bratsigovo-Dospat, Perelik and Kotili-Vitina. The ~300 m thick ignimbrites cover an area of 700 km2, 220 km2 and 350 km2, respectively. Our study demonstrates that these ignimbrites have identical ages of ~31.6 Ma and mineral and chemical compositions and are parts of a single large eruption. Based on these data, we suggest that the original areal coverage was much larger, possibly 3000 km2, with magma volume of ~1000 km3. These results classify the Perelik eruption as one of the largest European Oligocene supereruptions These ignimbrites have notably high phenocrystal content (40–50%) and are a relatively homogeneous chemical composition, which are characteristics features of the ‘monotonous intermediate’ ignimbrites. Here, we provide petrographic observations, and chemical and isotopic (Sr, Nd) analyses to explain the P-T conditions of crystallization of these ignimbrites.
Geochemical study of the organic matter from the southern part of the Maritsa Iztok Basin
Authors: Milakovska Zlatka , Stefanova Maya , Vladislavov Georgi , Vetseva Millena
Published: December 2023

A sequence of carbonaceous mudstones interlayering three lignite seams is characterized by geochemical proxies. The core samples studied came from a borehole drilled in Trojanovo-3 Mine of Maritsa Iztok Basin. The n-alkane molecular composition is dominated by the > C29 long-chain homologues, with a strong “odd” over “even” homologue predominance. In addition to, the prevailing smooth signature of n-alkane distribution attests for one major organic matter source – land-derived higher plants. The sesqui- and di-terpenoid assemblage specifies the prevalence of Cupressaceae, Taxodiaceae, and Podocarpaceae species in the coal-forming mire. The lupane-type triterpenoids registered are a sign for Betulaceae family presence. Biomarkers for herb, macrophyte and algal/bacterial contribution are also recognizable.
Trace element characteristics of pore water from the deep-sea sediments of the Interoceanmetal exploration area in the Clarion-Clipperton Fracture Zone, NE Pacific
Authors: Milakovska Zlatka , Hikov Atanas , Stoyanova Valcana , Peytcheva Irena , Abramowski Tomasz
Published: December 2023

The concentrations of Fe, Mn, Co, Cd, Zn, Cu, Mo, and As were registered in broad intervals and are elevated compared to the mean values for the ocean water. Vertical distributions of the element concentrations in the pore waters along four sediment cores show distinct differences, mainly for the elements Fe, Mn, Cu, and Zn. Bioturbation activities developed in the depth interval 7–15 cm could be a probable reason for the variation trends. The distributions for the elements As, Cd, Co and Zn are conservative type and the patterns for the Mo and Ni – scavenged type. The obtained pore water profiles are similar to the distribution trends for areas in the Eastern Equatorial Pacific and show different patterns from the pore waters from the Western Pacific.
Posušje bauxites in Bosnia and Herzegovina: A source of critical raw materials and a paleoclimatic marker
Authors: Peytcheva Irena , Bilić Šime , Georgiev Stoyan , Pavičić Ivica , Šumanovac Franjo , Hikov Atanas , Holma Marko , Guillong Marcel , Grubišić Ivan
Published: December 2023

The present study provides geochemical and geochronological data about Posušje bauxites in Bosnia and Herzegovina with the aim to characterize them as Critical Raw Materials (CRMs) sources and to put constraints on the time and genesis of the deposit. Boehmite is the bauxites’ main Al-bearing mineral, while gibbsite is a minor constituent. Hematite is the dominant Fe-phase, whereas goethite is rare. The chemical analyses indicate that the Al2O3 content ranges from 49.6 to 63.0 wt %, Fe2O3 varies from 16.5 to 33.7 wt % and the SiO2 content is usually <0.5 wt %. TiO2 content ranges between 2.6 and 3.2 wt %. Typical trace elements are V (353–787 ppm), Cr (498–1055 ppm), Zr (382–558 ppm), Sc (42–72 ppm), and Ga (40–47 ppm). The sum of REEs is 357–1112 ppm. The U-Pb zircon dating indicates an age of Posušje bauxite formation at 56.6±0.5 Ma. This age closely aligns with the global climatic event that occurred approximately 56 Ma ago, called Paleocene–Eocene Thermal Maximum (PETM).
Silver-impregnated zeolitized tuffs for environmental degradation of ozone
Authors: Barbov Borislav , Zaharieva Katerina , Karakashkova Petya , Penchev Hristo
Published: December 2023

The natural zeolites were ultrasonically treated and impregnated with silver nanoparticles. The surface stabilized silver nanoparticles dispersion was obtained using an effective electrochemical reduction method. The phase and elemental composition, structure of the Ag-impregnated zeolites (clinoptilolite and mordenite) was studied by various methods such as powder X-ray diffraction, X-ray fluorescence analyses and Fourier-transform infrared spectroscopy. The Ag-impregnated clinoptilolite and mordenite natural zeolite materials with 1.20 wt %, 0.97 wt %, 0.83 wt % and 1.18 wt % silver content were established by XRF analysis. As initial materials were used three types clinoptilolite from Beli Plast, Most, Golobradovo (Kardzhali, Bulgaria) deposits and mordenite from Lyaskovets deposit in Eastern Rhodopes, Bulgaria. The catalytic ability of Ag-mordenite and Ag-clinoptilolites was investigated in the ecologically important reaction of ozone decomposition. The Ag-loaded mordenite demonstrates the higher conversion degree of ozone more than 40% in comparison with Ag-clinoptilolite materials at room temperature.
Chemical composition аnd morphology of pyrite and marcasite in blue clay from the Maritsa East lignite basin, Bulgaria
Authors: Dimitrova Dimitrina , Tarassov Mihail , Yossifova Mariana , Vetseva Millena , Georgiev Stoyan , Tzvetanova Yana
Published: December 2023

Pyrite and marcasite aggregates were found in a sample of blue silty clay from an exploration drill core at the northern edge of the Troyanovo North mine, Maritsa East lignite basin, Bulgaria. The aggregates have various sizes – from 50 µm (single crystal twins) to 0.5 cm (large twinned aggregates). Pyrite occurs as single cubic and cuboctahedral crystals, penetrative twins forming oval-shaped aggregates with visible cubic to truncated octahedral habits. Marcasite occurs as single tabular, pyramidal crystals, but often as twinned (penetrative, parallel, contact) composite oval-shaped aggregates. Marcasite has higher trace element contents than pyrite. In both minerals are detected Mn, Co, Ni, Cu, Zn, Mo, As, Sb, Hg, Tl and Pb with varying contents. The crystal aggregate growth is slow in varied supersaturation and pH due to the occurrence of both octahedral and cubic faces in pyrite and marcasite presence.
Preliminary data on the mineral chemistry of garnet from the skarn alteration associated with the Elatsite porphyry-copper gold deposit, Bulgaria
Authors: Georgieva Hristiana , Nedialkov Rossen , Stefanova Elitsa , Milenkov Georgi , Krumov Ivan , Georgiev Neven
Published: December 2023

The skarn alteration is poorly preserved at the Elatsite, restricted to the hornfelses from the East, Southeast and Southern part of the deposit. The rocks are defined as exoskarns, with a mineral composition including garnets, epidote, pyroxene, amphiboles, carbonates, prehnite, quartz, sulphides. The newly formed minerals occur in poorly preserved layers. The garnet grains are subhedral with inclusions of epidote and quartz, while some of them are corrode with carbonate and zeolites formed in the fractures. The garnets are grossular-andradite type, with higher values for HREE over LREE, and low values for Rb, Sr, Ba, Pb and U. The skarn formation is related with the intrusion of the magma which causes the heating of the metamorphic rocks (rich in carbonate material – chlorite-sericite-carbonite, sericite-carbonate schists, etc.) from the low-grade metamorphic rocks. The Fe+3–Al+3 exchanges in the cores of the garnets indicate their formation from fluids with high oxygen fugacity.
Redistribution of incompatible elements during hydrothermal alteration of pegmatite from the Djurkovo Pb-Zn deposit, Central Rhodopes
Authors: Georgieva Sylvina , Vassileva Rossitsa D. , Grozdev Valentin , Milenkov Georgi , Cempírek Jan , Škoda Radek , Stefanova Elitsa
Published: December 2023

Mineralogical and geochemical study was done on weakly deformed, relatively thin pegmatites that intruded the marbles of the Rhodope metamorphic complex in the Djurkovo Pb-Zn deposit, Central Rhodopes. The pegmatites consist mainly of K-feldspar and quartz and contain minor garnet; the pegmatites lack clear zonation except for the preferable crystallization of the garnet in the central parts. The main accessory minerals are ishikawaite, zircon, monazite-(Ce), apatite, and titanite. The textural relationships indicate later hydrothermal alteration of pegmatites which led to the formation of albite, epidote, sericite, chlorite, carbonate, quartz and leucoxene. The (REE+Y, ACT, Nb, Ta, Ti)-bearing pegmatite minerals (oxides, silicates and phosphates) are partly leached and/or replaced by secondary ones. The newly-formed phases precipitated as anhedral grains along fractures and dissolved zones onto/or close to the primary minerals due to the limited mobility of the incompatible elements in fluids conditioned by pH, ligand activity and temperature.
Planerite with aheylite and faustite from the Chala deposit, Spahievo Ore Field
Authors: Nesheva Larisa , Yanakieva Denka , Petrov Petko , Atanasova-Vladimirova Stela , Petrova Nadia , Vassileva Rossitsa , Sergeeva Ivanina , Cherkezova-Zheleva Zara , Paneva Daniela
Published: December 2023

Planerite, aheylite and faustite are minerals of the turquoise group. They were found in samples from the Chala deposit, Spahievo Ore Field. The samples consist of a small crystalline mass of the investigated mineral phases among quartz. Single spherulites up to 2 mm in size and aggregates of spherulites with a yellowish-greenish color are observed in small cavities. Transparent, colorless wavellite crystals and aggregates are crystallized on spherulites. For the first time in Bulgaria, the presence of aheylite was established.
Sulphate mineralization from one locality in Lozen ore field, Eastern Rhodopes
Authors: Nikolova Rositsa , Kostov-Kytin Vladyslav , Petrov Petko , Tsvetanova Liliya , Gospodinov Nikolay , Metodieva Kristina
Published: December 2023

A suite of sulphates from a locality in Lozen ore field in the Eastern Rhodopes has been characterized by chemical analyses and X-ray diffraction. Three mineral species have been identified: epsomite (MgSO4), pickeringite (MgAl2(SO4)4•22H2O) and alunogen (Al2(SO4)3•17H2O). An attempt was made to characterize the phase transformations that occur upon wetting of the studied samples. The results show that at high humidity, pickeringite dissolves, providing constituents for subsequent crystallization of epsomite and alunogen. Further on, upon drying alunogen loses some of its crystallization water and recrystallizes again to pickeringite including magnesium species from the surrounding medium. This study draws light on certain genetic aspects related to the mechanisms and sequence of deposition of sulphate mineralization under similar conditions.
Interaction of sodalite and cancrinite with NH4NO3 solution. First case of low-temperature synthesis of buddingtonite
Authors: Stanimirovа Tsveta , Kirov Georgi
Published: December 2023

Hydroxyl sodalite and sulfate cancrinite were synthesized from fly ash from TPP Varna, Bulgaria. The interaction of the two feldspathoids with NH4NO3 solution at 90 °C was investigated. Because of the reaction, sodalite is dissolved and ammonium feldspar (buddingtonite) is formed, which is the first case of low-temperature synthesis of this mineral. The interaction of cancrinite with NH4NO3 induces ion exchange and the formation of cancrinite with composition (NH4)5.4Na3.6(NO3)1.45(SO4)0.25(OH)0.05[Al6Si6O24]·2H2O, suggesting potential for the use of this form as a slow-acting fertilizer.
Colloform sphalerite in Pcheloyad Pb-Zn deposit, Eastern Rodopes, Bulgaria
Authors: Stariradeva Svetla , Petrov Petko , Yanakieva Denka
Published: December 2023

A late-deposited colloform banded sphalerite from Pcheloyad and Sporno deposits in samples from the Earth and Man National Museum was studied. Its composition is very close to the theoretical one for sphalerite. Iron, gallium, cadmium and indium are established as trace elements in concentrations lower than those in earlier deposited sphalerite generations. The presence of wurtzite was proved by X-ray powder diffraction. A similar low-temperature colloform banded sphalerite of the Schalenblende type has so far not been described in the lead-zinc Zvezdel-Pcheloyad ore field.
Garnet (REE+Y)-bearing mineral association in pegmatite from the Chepino lithotectonic Unit, Western Rhodopes
Authors: Vassileva Rossitsa D. , Georgieva Sylvina , Cempírek Jan , Grozdev Valentin , Škoda Radek , Stefanova Elitsa
Published: December 2023

Large pegmatite body/bodies are outcropping in the “Suhata Reka” quarry, near the town of Rakitovo. Their bulk mineral composition with dominant K-feldspar (40%), plagioclase (30%), quartz (25%) and mica (≤ 5%) is complemented by (REE+Y)-bearing association of primary and secondary accessories. Zircon, monazite, xenotime, scarce apatite and noticeable amount of garnet are among the pegmatite primary minerals. The cm-sized almandine-spessartine crystals contain numerous fractures which host secondary (REE+Y)-bearing phosphate (xenotime, cheralite) and silicate minerals (e.g. REE-epidote). Formation of the late-stage REE-mineralization in garnet is due to its hydrothermal alteration and redistribution of REE+Y in the secondary phases.
Millerite from the Madan ore field
Authors: Petrov Petko
Published: December 2023

Millerite is discovered in samples from Krushev Dol and Mogilata deposits in the Madan ore field. It was found in two associations different in appearance and mineral composition. One of them is with light green ferro­dolomite, and the other with bright green mariposite (chromium-bearing phengite). Only cobalt and iron are detected as impurity elements in some analyses. They are in small concentrations (below 0.01 apfu). The Ni/S ratio is 0.95. The nickel source is associated with bodies of serpentinized ultramafics cut by ore-bearing veins.
Efficient benchtop acid digestion of organic-rich sediments for ICP-MS analyses: testing analytical procedures on NIST 2702 standard reference material
Authors: Bidzhova Lora , Raeva Emiliya D. , Morin Gatien L. F. , Georgiev Svetoslav V.
Published: December 2023

Trace element abundances in organic-rich sediments are widely used in various fields of the geosciences, yet few contributions discuss the effectiveness of low-cost benchtop acid digestion techniques for such samples. Here, we tested three different sample preparation methods (acid digestion in closed and open vessels, and fusion) on twelve powder aliquots of organic-rich sediment, standard reference material NIST 2702. Comparison of newly obtained ICP-MS and LA-ICP-MS results with their respective certificate values, facilitates the assessment of digestion efficiency and the effects of vessel size, acid mixture, and other parameters on the recoveries of 29 trace elements. Our results show that benchtop digestion of organic-rich sediment in closed 7 mL PFA vessels using HF+HNO3+HClO4 mixture is more efficient compared with open vessel digestion treated with the same acid mixture (± HCl), with closed or open vessel digestions without HClO4, and with LA-ICP-MS measurements on fused glass discs.
Petrography and geochemistry of Cretaceous bauxites from Jajce, Bosnia and Herzegovina
Authors: Bilić Šime , Peytcheva Irena , Georgiev Stoyan , Hikov Atanas , Pavičić Ivica , Deljak Gordana , Šumanovac Franjo , Holma Marko
Published: December 2023

The study presents petrographic and compositional data of Late Cretaceous bauxite deposits in the area of Jajce, Bosnia and Herzegovina. Results indicate that bauxites exhibit ooidic to pisodic textures enclosed within a pelitomorfic matrix. Most of the deposits are boehmitic but in some localities, a considerable quantity of diaspore is identified. Hematite is the dominant Fe-mineral, while kaolinite, goethite and calcite are minor. The accessory minerals are represented by anatase, rutile and zircon. Al2O3 content ranges between 54.32–61.05 wt % and is negatively correlated to Fe2O3. Rare earth elements (REE) show variable concentrations, reaching up to 1353 ppm. The chondrite normalized patterns reveal negative Eu anomaly in all and positive Ce anomaly in almost all samples. Ce anomaly shows negative correlation with REE. Bauxites from the Jajce area represent valuable mineral resource with potentially valuable quantities of REE and Sc. Mineralogy and geochemical signature indicate a complex petrogenetic history.
Carboniferous sills and related metasomatic activity in the area of Asaritsa Peak, West Stara Planina Mountain
Authors: Georgiev Stoyan , Stefanova Elitsa , Hikov Atanas , Peytcheva Irena , Sachanski Valeri , Stavrev Milen
Published: December 2023

Two diorite to monzodiorite sills are recently found among the Silurian sedimentary succession near to Asaritsa peak, West Stara Planina Mountain. Several levels with diagenetic metalliferous nodules occur within shale interval in the sediments. The magmatic rocks are affected by strong propylitic to sericitic alteration (chlorite, sericite, albite and quartz) and only relicts of the rock-forming minerals (feldspar, biotite and clinopyroxene) are observed. The bodies are crosscut by thin quartz veins and disseminated pyrite is observed. The chondrite normalized spidergrams show patterns similar to orogenic rocks, with very high peaks of Th and U and depletion in Sr and Ti. The zircon U-Pb geochronology reveals that the magmatic crystallization is during the Carboniferous period – 326.4±3.2 Ма, with low content of xenocryst most probably from the sedimentary basement. The magmatic activity coincides with the Variscan orogeny formed during the late Paleozoic and most probabaly is related to the evolution of the alkaline Buhovo-Seslavtsi Pluton which is situated just to the south, at a direct proximity. The different composition of the pyrite from the sills and the diagenetic nodules from the sediments is most probably due to their different genesis. While the alterations of the nodules can be attributed to metasomatic processes related to the magmatic activity.