Theses (Faculty of Science and Technology)
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A DE Természettudományi és Technológiai Kar Tanácsának 2009. november 25.-i határozata alapján a jövőben elektronikus formában is elhelyezésre kerülnek a szakdolgozatok a Debreceni Egyetem Egyetemi és Nemzeti Könyvtár által működtetett egyetemi archívumban, a DEAba. A szakdolgozatok az archívumból kizárólag a Debreceni Egyetem IP-címeiről hozzáférhetőek, azokat nem lehet kinyomtatni, és azokból szövegrészeket nem lehet kiemelni.
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Megjelenítve 1 - 20 (Összesen 672)
Tétel Korlátozottan hozzáférhető Synthesis and characterization of gelatin aerogels as drug carriersDauzhanova, Diana; Forgács, Attila; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThis work studies a synthesis, characterization and application of gelatin-based aerogels. The aim was to create aerogels which are able to release ascorbic acid under given conditions. This tecnhique could be applied for targeted drug delivery. Physico-chemical properties of synthesized materials were studied by FT-IR, N2-porosimetry and SEM analysis. Ascorbic acid content was determined by spectrophotometric methods.Tétel Korlátozottan hozzáférhető Failure Processes of Bundles of Plastic FibersDo, Huyen Anh; Kun, Ferenc; DE--Természettudományi és Technológiai Kar--Fizikai IntézetThis study explores the failure processes of bundles of plastic fibers within plastic fiber-reinforced composite materials (PFRCs), based on fiber bundle models (FBMs) that incorporate elastic-plastic behavior and statistical variations in yielding and breaking thresholds. The investigation includes analytical derivation and numerical simulations to model the macroscopic and microscopic failure mechanisms of plastic fiber bundles. Results indicate a transition from gradual to abrupt failure as the plastic coefficient decreases, with catastrophic failure occurring when the weakest fiber initiates collapse. Failure proceeds through avalanches, characterized by power-law size distributions, whose statistical properties depend on the plastic coefficient and stress field heterogeneity. Finite-size scaling analysis reveals critical exponents and identifies the transition as analogous to continuous phase transitions. The study provides significant insights into the fracture dynamics of PFRCs, offering a basis for predicting material behavior under mechanical loads and improving the reliability of composite materials in engineering applications.Tétel Korlátozottan hozzáférhető Analysis of fluid inclusion stable isotopes using laser spectroscopyAhmed, Aqeel Ahmed Tanseer; Palcsu, László; DE--Természettudományi és Technológiai Kar--Fizikai IntézetThe analysis of stable isotopes within fluid inclusions represents a powerful tool in reconstructing past environmental and climatic conditions. Fluid inclusions, minute pockets of ancient water trapped within minerals such as speleothems, preserve the isotopic signature of the ambient fluids from which the host mineral precipitated. Laser spectroscopy, in our case using systems developed by Los Gatos Research (LGR),have revolutionized this field by enabling high-precision measurements from micro-scale water samples with minimal preparation. LGR’s Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) combines sensitivity and efficiency, making it ideal for analyzing scarce inclusion fluids. This method has become essential in palaeoclimate studies, enhancing our ability to reconstruct temperature, precipitation, and atmospheric circulation patterns across geological timescales.Tétel Korlátozottan hozzáférhető INVESTIGATION OF SURFACE-ENHANCED RAMAN SCATTERING VIA METALLIC NANOPARTICLESGanbold, Anujin; Csarnovics, István; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThis thesis will explore the contribution of nanoparticles in enhancing Raman spectrometry, focusing on advances made so far in sensitivity, resolution, and applicability in a wide range of field applications. As a powerful optical technique, Raman spectrometry depends on the inelastic scattering of light to identify vibrational modes of molecules. However, it exhibits rather low sensitivity due to the weak Raman signal by nature. Introducing nanoparticles, especially through surface-enhanced Raman spectroscopy, increases the Raman signal enormously and permits the detection of trace molecules at a high level of detail. Among the various types of nanoparticles discussed here is the focus on gold and silver for their unique optical properties that enhance the electromagnetic field at the nanoscale level. This thesis will conduct experimental and theoretical investigations to see how nanoparticle morphology, size, and material composition affect Raman enhancement. The results show that optimizing the parameters of the nanoparticles leads to an improvement in the analytical capability and opens the way to new sensing technologies with high sensitivity and specificity.Tétel Korlátozottan hozzáférhető Identification and Elimination of Pitfalls in Single-Crystal X-ray Diffraction Structure Determination: A Case StudyIurgenson, Nika; Bényei, Atilla; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThe focus of the current thesis is to reveal and explain the common pitfalls that crystallographers can encounter on the measurement and further stages of structure research, as well as to suggest ways of resolving these issues for attaining highly consistent and reliable structure solutions. The current writing is backed up by practical examples of complete structure determination of molecules with code names NA-134 and NA-138. The thesis includes detailed consideration of structure solution steps from the moment of crystal selection to final structure refinement and validation. These molecules are the novel carbohydrate-based compounds possessing the potential to exhibit antidiabetic effects as SGLT2 inhibitors. The compounds were obtained for structure determination from the organic synthesis research group of the Department of Organic Chemistry at the University of Debrecen. The current thesis can serve as a practical guide in the field of SCXRD.Tétel Korlátozottan hozzáférhető Purification of Cyclotron Produced Gallium-68 and Copper-61Macit Mutlu, Bengü; joszai, istvan; szikra, dezsö; DE--Természettudományi és Technológiai Kar--Kémiai IntézetMy thesis focuses on Purifying Gallium-68 and Copper-61, isotopes used in medical imaging (PET scans). It essentially compares different methods and materials for producing these isotopes using a cyclotron. The most efficient method I delineated was using a specific type of resin and optimizing irradiation parameters.Tétel Korlátozottan hozzáférhető Comparing biodiesel quality based on a feedstock used from Thailand and BrazilSaipetch, Chris; Akos, Kuki; DE--Természettudományi és Technológiai Kar--Kémiai IntézetComparing the products produced from two global leading biodiesel production from two different feedstocks. Gathered and engineered the production line in Chemcad8 to simulate the process and determine the contaminants. With the results obtained, products specifications are to observed and analyst. Various factors can be affecting the specifications along with the quality of the feedstocks. In the end, Brazil production line from what we engineered is the better one for producing high-quality biodiesel.Tétel Korlátozottan hozzáférhető Hydro-morphological Analysis on the Surma River in Bangladesh over the past decadeRahman, Samin Yasar; Bertalan , László; DE--Természettudományi és Technológiai Kar--Földtudományi IntézetI used hydrological parameters which are Rainfall, Water level and Discharge data to combine it with satellite data to obtain trends in the Surma river for the last decade (2015-2024). I also calculated erosion rates for four bends using the satellite image and also derived relations between the erosion rates and discharge data combining hydrological and satellite data.Tétel Korlátozottan hozzáférhető Identifying Prospective Areas for the Chatree Epithermal Gold Region from Airborne Magnetic Data Using Advanced Analyzing Techniques, with Interpretative CorrelationPinkaew, Kanoknapat; Buday, Tamás; DE--Természettudományi és Technológiai Kar--Földtudományi IntézetThe Chatree Region, located in central Thailand, holds significant potential for gold exploration, hosting substantial mineral resources. The complex geological setting of this region, with its diverse lithologies and intricate structural controls, poses both significant opportunities and challenges for successful mineral exploration. Given these challenges, this study utilizes a geophysical approach focusing on magnetic data interpretation to enhance the precision and efficiency of identifying potential gold prospects. Enhancements to the magnetic data were achieved through the application of Downward Continuation (DWC) and Automatic Gain Correction (AGC), which amplified near-surface features and improved signal clarity. Subsequently, by employing the Centre for Exploration Targeting (CET) Grid Analysis, zones of structural complexity, indicative of epithermal gold deposits were detected, which generated two heat maps, including Contact Occurrence Density (COD) and Orientation Entropy (OE). These maps revealed six major and seven minor potential gold prospect zones, providing a critical dataset for subsequent geological analysis. Geological correlations and lineament interpretation were then conducted to validate and refine the magnetic interpretations by integrating several filtered magnetic images with existing geological knowledge of the region. The results of this integrated approach show that many of the identified magnetic anomalies and lineaments correlate with known geology, highlighting the critical role of synthesizing advanced magnetic data analysis with geological expertise. This integration provides a valuable foundation for future exploration in the region and establishes an applicable methodological approach to other mineral exploration effortsTétel Korlátozottan hozzáférhető Variations in Sulphur related Cu – Ni and PGE Deposits, Bathtub Intrusion Duluth Complex: MN, USA.Mann, Benjamin Ross; Benko, Zsolt; DE--Természettudományi és Technológiai Kar--Földtudományi IntézetThis paper will provide an analysis of the variations in Cu-Ni-PGE (PGE refers to Platinum Group Elements here and throughout this paper) In the Bathtub Intrusion ore mineralisation zone. The bathtub complex is located in northeastern Minnesota nestled between the Canadian border and Lake Superior it is a part of the Duluth Complex. It has been an area of interest throughout the years because of these high demand resources however the feasibility of the area has been handicapped by a poor understanding of the development and structure of the ore body. It is a layered igneous intrusion apart of the North American Craton from around the Proterozoic age. During the formation of ore deposits on the edge of the complex there was heavy interaction with the neighbouring foot wall this has made the organisation of the sulphides hard to identify. This footwall provided the sulphur necessary for ore formation but also the conditions necessary to allow major fractionation. Pairing this with the pulsing magma as well as a later hydrothermal period introduced by fluids in the initial sulphur melt and this has left the complex highly variable. This paper analyses concentration data isotope data as well as thin sections to try and decipher the variability and pull together a cohesive overview of the ComplexTétel Korlátozottan hozzáférhető Evaluating Global Digital Elevation Models for GIS-Based Flood Inundation Mapping in the Sarawak River, MalaysiaBakri, Sorfina; László, Bertalan; DE--Természettudományi és Technológiai Kar--Földtudományi IntézetThe study focuses on a Sarawak River in east Malaysia, which falls under the 10.1% areas in Malaysia that are prone to flooding. The river is located around the provincial capital of Sarawak, Kuching. Furthermore, it is characterized by its meandering course and low-lying terrain which shows geographical complexities. The interplay of dynamic factors makes the Sarawak River a critical area to research for flood modelling. The tools that can be used for this are Geoinformatics Geographic Information Systems (GIS) and remote Remote sensing Sensing methods which provide valuable geospatial data from the investigated area. The methodology employs a GIS-based process model to estimate inundation extents for predefined water levels, enabling comparative analysis of flood-prone areas derived from different DEMs with varying topographic representations and spatial resolutions. Additionally, cross-sectional profiles at multiple river segments are extracted to assess and evaluate the accuracy of geometric reconstruction across the DEM datasets.Tétel Korlátozottan hozzáférhető Environmental Impact Assessment ( EIA ) scoping report for a limestone mining project in GhanaAwuni, Jude Kwadjo; McIntosh, Richard William; DE--Természettudományi és Technológiai Kar--Földtudományi IntézetThis thesis shows the Environmental Impact Assessment ( EIA ) scoping report for a proposed limestone mining project in Yilo Krobo in Ghana. This thesis helps to identify the potential environmental and social impacts which includes land degradation and some community concerns. It also represents baseline environmental data , project alternatives and some mitigation measures. It also has a term of reference which should align with the rules and regulation of the environmental department of the country and also should help promote sustainability.Tétel Korlátozottan hozzáférhető PETROGRAPHIC AND STABLE ISOTOPE ANALYSIS OF CARBONATITE SAMPLES OF THE NEWANIA CARBONATITE COMPLEXNagar, Sarthak; Benkó , Zsolt; DE--Természettudományi és Technológiai Kar--Földtudományi IntézetThis thesis presents a detailed petrological and mineralogical study of the Newania Carbonatite Complex. The work involves thin section analysis to document mineral assemblages, textures, and alteration features. Additionally, stable isotope analysis using C¹³ and O¹⁸ ratios has been employed to infer insights into the origin and evolutionary processes of the complex.Tétel Korlátozottan hozzáférhető Legacy of Gemstones- A historical and scientific review of gemstonesManso-Marfo, Michael; Csamer, Arpad; DE--Természettudományi és Technológiai Kar--Földtudományi IntézetA comprehensive journey into gemology, a scope into its historic and scientific studies, highlighting the various processes used in both ancient and modern civilizations, discussing their market values, and their significance to the world.Tétel Korlátozottan hozzáférhető The comparison of Value at Risk, Expected Short-fall, and Gini measure and its applicationsAlhalibi, Yassin; József, Gáll; DE--Természettudományi és Technológiai Kar--Matematikai IntézetThis thesis studies some of the most used risk measures - Value at Risk (VaR), Expected Short-fall(ES), and Gini measure and their applications. The most often used risk indicator in financial risk management is Value at risk. However, VaR will have some flaws when it comes to measuring extreme risks.Tétel Korlátozottan hozzáférhető A Quick Study on The Basics of Dynmaical Fields and Their PotentialsABDELRAZEQ, ALHASAN; Trócsányi , Zoltán; DE--Természettudományi és Technológiai Kar--Fizikai IntézetAmong the most compelling topics within this discipline are the dynamics of cosmological fields and the enigmatic forces driving the universe’s accelerated (or decelerated) expansion, commonly attributed to dark energy. This thesis embarks on a systematic study of dynamical fields, delving into their mathematical formulations, physical interpretations, and cosmological implications.Tétel Korlátozottan hozzáférhető Convergence properties of one and multidimensional trigonometric Fourier seriesAllauca Guananga , Steven Gerónimo; Tamás, Gát György; DE--Természettudományi és Technológiai Kar--Matematikai IntézetIn this work, first of all, we study the convergence properties of one and multidimensional trigonometric Fourier series. It begins by discussing fundamental concepts such as vec- tor spaces, function spaces, and interpolation theorems. Inspired by Fourier analysis, it explores the feasibility of extending these concepts to infinite-dimensional spaces and or- thonormal systems. The study extensively covers the convergence behavior of Fourier series in the one-dimensional case, including partial sums, Dirichlet kernels, Fourier coefficients, and convergence criteria. It also examines the concept of Fej´er means. In the multidi- mensional context, the thesis explores topics such as partial sums, norm convergence, and summability means. Throughout the thesis, we use and refer to books [1] and [2], as well as the lectures given by my supervisor in his ”Fourier series” lectures [3]. What results are not directly referred to are taken from lectures [3, 4]. No new statements or results have been formulated in the thesis.Tétel Korlátozottan hozzáférhető Development of a LoRa-based data acquisition system for health monitoringAgha, Chukwumela; Harasztosi , Lajos; DE--Természettudományi és Technológiai Kar--Fizikai IntézetThis thesis focuses on the realization of a LoRa-based data acquisition system intended for health monitoring. The project establishes a Point to Point (P2P) communication model. The system employs a temperature sensor for data acquisition to enable wireless transmission of data over long distances with less power requirements. An example of how the system works in health monitoring situations is provided by the alert mechanism that activates in case of temperature changes. The components involved include PCBs, software that provides interaction between the components and the display of data. The thesis focuses on the ability of LoRa P2P systems to deliver an efficient, reliable and affordable way of implementing healthcare solutions for remote patient monitoring.Tétel Korlátozottan hozzáférhető 15-membered rigid macrocyclic ligand for Mn2+ complexation: synthesis and coordination chemical characterizationBaghirova, Aghanana; Tircsó, Gyula; DE--Természettudományi és Technológiai Kar--Kémiai IntézetThe investigation of Mn²⁺ chelates as alternatives to Gd³⁺-based MRI contrast agents has gained significant attention due to their promising safety and performance profiles. My research focused on the synthesis and coordination chemistry of a novel 15-membered bipyridine-based macrocyclic ligand, 15-BPyN5. The ligand demonstrated excellent thermodynamic stability (log K_MnL = 13.44), high kinetic inertness, and favorable relaxivity properties (r1p/r2p = 3.60/6.60 mM⁻¹s⁻¹). Dissociation studies revealed slow exchange kinetics with Zn²⁺ ions, with half-lives of 79.0 and 28.7 hours at 25°C and 37°C, respectively, attributed to the rigid coordination environment provided by the bipyridine moiety. These properties highlight the potential of [Mn(15-BPyN5)] as a safe and effective MRI contrast agent. This work paves the way for developing non-toxic alternatives to gadolinium-based agents, offering improved safety and imaging performance.Tétel Korlátozottan hozzáférhető DEVELOPMENT OF A SYSTEM FOR BATTERY CELL TESTINGA.A. Lulu, Ali; Harasztosi, Lajos; DE--Természettudományi és Technológiai Kar--Fizikai IntézetThis Thesis focuses on the development and optimization of a testing system for battery cells, while focusing on LIBs due to their daily uses in our modern society and time, the key challenges and features in the performance, safety, and life span can be addressed through the design of a testing system. The Development of battery cell testing offers a way to safely test the performance of the lithium-ion batteries very effectively and easily. It also focuses on the process of creating a PCB design in which it Charges the Lithium-ion battery at a constant current, and how does it discharge it at a constant current. It describes the difference between an old battery and a new lithium ion battery in there capacity, voltage rise, voltage drop, ,the time for them to fully charge, and state of charge. The document expresses the importance of how to optimize the battery and how to safely test the lithium-ion battery.