33 results on '"Kovač, Nataša"'
Search Results
2. Urinary tract infections in children with cancer and febrile neutropenia - single center experience
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Kovač Nataša, Samardžić-Lukić Maja, Kaćanski Nataša, Kovač Aleksandra, Latinović Tijana, and Kolarović Jovanka
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bacteriological techniques ,child ,febrile neutropenia ,medical oncology ,urinary tract infection ,urinalysis ,Medicine (General) ,R5-920 - Abstract
Background/Aim. Urinary tract infection (UTI) in children with febrile neutropenia (FN) after receiving chemotherapy could be followed by atypical symptoms and signs. The absence of routine urine culture (UC) sampling for analysis could lead to undiagnosed disease and inadequate treatment of these patients. The aim of the study was to indicate the importance of sampling UC in children who have developed FN and to point out the most probable causative agents of UTI in children with FN and antibiotic sensitivity/resistance of the isolated strains. Methods. During a five-year observation period, 40 UTIs were registered in 30 patients with FN. In the study group of patients with FN, the number of UTIs, the number of recurrent UTIs, isolated pathogens, their sensitivity to antibiotics, characteristics of urine sediment, the presence of localized symptoms of UTI, and the presence of urosepsis were analyzed. The obtained results were compared with the control group which consisted of children who were healthy prior to hospitalization due to febrile urinary infection. Results. When compared to the control group, significant differences in the presence of symptoms of UTI and urine sediment findings in patients with FN were observed. A higher percentage of resistant strains of Escherichia coli isolated from UC of cancer patients with FN was noted when compared to the control group. Three UTI cases were followed by urosepsis. Conclusion. UC findings are important not only in establishing the diagnosis of UTI and detecting multi-resistant bacterial strains but also in choosing appropriate antibiotics and selecting a subgroup of patients with recurrent UTI who require further monitoring and detecting potential complications in a timely manner.
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- 2024
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3. Corrosion-induced thickness diminution of an ageing bulk carrier.
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Kovač, Nataša, Ivošević, Špiro, and Momčilović, Nikola
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SUSTAINABILITY , *STRUCTURAL optimization , *SUSTAINABLE development , *PETROLEUM as fuel , *RANDOM variables - Abstract
The 2030 Agenda for Sustainable Development introduced 17 Sustainable Development Goals (SDGs). The International Maritime Organization (IMO) has endorsed connections between the maritime sector and SDGs, emphasising sustainable production in the marine environment. Consequently, technical considerations, such as ship structure sustainability, are crucial for marine safety. The impact of corrosion influences the structural degradation of vessels and the risk of structural failure and fuel oil spills significantly. The formulation of predictive corrosion models, grounded in historical data accumulated during vessel operations, emerges as an optimal strategy for designing structural elements and guaranteeing their structural integrity. This paper analyses non-linear deterministic and stochastic corrosion models, focusing on an ageing bulk carrier, to provide design-phase information for sustainable structures. Utilising data on measured steel plate thickness over a 20-year operational period, nonlinear models are employed to calculate the millimetres of thickness diminution. Assuming corrosion onset at 7, 8, and 9 years, corresponding coefficients are computed, based on the developed model. A model is also considered, in which there were no assumptions about the beginning of corrosion initiation. The corresponding annual corrosion rate was observed separately in each of the models, as a deterministic variable and as a probabilistic random variable. This approach aims to enhance the understanding of the causal relationship between corrosion processes and structural performance, contributing to the development of sustainable design practices in the maritime industry. [ABSTRACT FROM AUTHOR]
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- 2024
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4. On the exact analytical formula for dimensionless injection rate in CO2 storage based on Special Trans Functions Theory
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Perovich, Slavica M and Kovač, Nataša
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- 2022
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5. Challenges to Viticulture in Montenegro under Climate Change.
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Fernandes, António, Kovač, Nataša, Fraga, Hélder, Fonseca, André, Šućur Radonjić, Sanja, Simeunović, Marko, Ratković, Kruna, Menz, Christoph, Costafreda-Aumedes, Sergi, and Santos, João A.
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MEDITERRANEAN climate , *ATMOSPHERIC models , *VITICULTURE , *GROWING season ,ROMAN Empire, 30 B.C.-A.D. 476 - Abstract
The Montenegrin climate is characterised as very heterogeneous due to its complex topography. The viticultural heritage, dating back to before the Roman empire, is settled in a Mediterranean climate region, located south of the capital Podgorica, where climate conditions favour red wine production. However, an overall increase in warmer and drier periods affects traditional viticulture. The present study aims to discuss climate change impacts on Montenegrin viticulture. Bioclimatic indices, ensembled from five climate models, were analysed for both historical (1981–2010) and future (2041–2070) periods upon three socio-economic pathways: SSP1-2.6, SSP3-7.0 and SSP5-8.5. CHELSA (≈1 km) was the selected dataset for this analysis. Obtained results for all scenarios have shown the suppression of baseline conditions for viticulture. The average summer temperature might reach around 29.5 °C, and the growing season average temperature could become higher than 23.5 °C, advancing phenological events. The Winkler index is estimated to range from 2900 °C up to 3100 °C, which is too hot for viticulture. Montenegrin viticulture requires the application of adaptation measures focused on reducing temperature-increase impacts. The implementation of adaptation measures shall start in the coming years, to assure the lasting productivity and sustainability of viticulture. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Probabilistic estimates of corrosion rate of fuel tank structures of aging bulk carriers
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Ivošević, Špiro, Meštrović, Romeo, and Kovač, Nataša
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- 2019
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7. Digital divide and digitalization in Europe: A bibliometric analysis.
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Kovač, Nataša, Żmija, Katarzyna, Roy, Jewel Kumar, Kusa, Rafał, and Duda, Jerzy
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DIGITAL transformation , *DIGITAL divide , *BIBLIOMETRICS , *DIGITAL inclusion ,WESTERN countries - Abstract
Research background: Digitalization and the associated digital divide are crucial issues impacting socio-economic development globally. Extensive research has examined digitalization and the digital divide in EU countries, but there is a lack of understanding regarding comparisons with studies conducted in Western Balkan countries. This study investigates digitalization trends in research from the past five years in both regions, focusing on efforts and factors contributing to the digital gap. Purpose of the article: The study analyzes research on digitalization from 2018 to 2023 in the EU and Western Balkans. It explores factors causing the digital divide and efforts in digitalization, aiming to guide future research and policy for digital inclusion and sustainable development. Methods: The study employs a meticulous data selection process, choosing Scopus as the database for its extensive coverage of diverse journals. A total of 1119 articles from EU countries and 277 from Western Balkan countries are selected for bibliometric analysis, adhering to PRISMA guidelines. Findings & value added: The research reveals a growing interest in digitalization-related issues, demonstrating the multidisciplinary nature of ongoing research. It points out the distribution of publications on digitalization in the EU and Western Balkans countries. The EU focuses on digital technologies, economic growth, and sustainability, while Western Balkan countries focus on COVID-19 impact and digitalization in education and business. The research compares digitalization efforts in the EU and Western Balkan countries presented in the literature, pointing to new dimensions of the digital divide studies. It discusses how socioeconomic contexts affect digital transformation and stresses the need for tailored policy approaches for digital inclusivity. These insights are of great importance for policymakers, researchers, and practitioners working towards global digital development and bridging the digital divide. The study lays the groundwork for future research and policy considerations, considering limitations like potential bias in databases and search criteria. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Secondary lymphedema of the arm, the perception of the disease, self-efficacy and depression as determinants of quality of life in patients with breast cancer
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Popović-Petrović Svetlana, Kovač Aleksandra, Kovač Nataša, Tovilović Snežana, Novakov Ivana, and Ćulibrk Dragan
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breast neoplasms ,woman ,upper extremity ,lymphedema ,quality of life ,perception ,depression ,Medicine (General) ,R5-920 - Abstract
Background/Aim. Secondary lymphedema of the arm is one of possible side-effects and complications of breast cancer and its treatment which can contribute and precipitate to a number of new psychosocial problems. The aim of this study was to examine the differences in quality of life of patients suffering from breast cancer, with arm lymphedema and those without lymphedema, and to determine the significance of the perception of the disease, depressive symptoms and self-efficacy contribution to overall quality of life. Methods. The research was designed as a cross-sectional study, which included 64 patients – 34 with arm lymphedema and 30 without lymphedema. Questionnaire FACT-B + 4 was applied to assess the quality of life, BIPQ for the perception of the disease, depression was measured by DASS-21 scale, while self-efficacy was tested by SGSE scale. T-test, Mann Whitney U Test, χ2 test and hierarchical regression analysis were applied to data processing. Results. There was not any significant difference between the groups in the total score of quality of life (t = 0.469, p > 0.05), or in the individual subscales: physical well-being (t = 0.535, p > 0.05), social/family well-being (t = 1.43, p > 0.05), emotional well-being (t = 1.35, p > 0.05), functional well-being (z = -0.243, p > 0.05), breast cancer scale (t = -0.839, p > 0.05) and arm scale (t = -0.514, p >0.05), while the perception of the disease (β = -0.603, t = -5.958, p < 0.001) and depression (β = -0.411, t = - 4.101, p < 0.001) proved to be significant predictors of quality of life and explain 50.2% variance of overall quality of life. Conclusion. The results of our study indicate the importance of a comprehensive rehabilitation program, directed both at functional and psychosocial aspects.
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- 2018
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9. Serum glutathione S-transferase Pi as predictor of the outcome and acute kidney injury in premature newborns
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Stojanović, Vesna D., Barišić, Nenad A., Radovanović, Tanja D., Kovač, Nataša B., Djuran, Jelena D., Antić, Amira Peco E., and Doronjski, Aleksandra D.
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- 2018
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10. Metaheuristic approaches for the Berth Allocation Problem
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Kovač Nataša
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container terminal ,assignment of vessels ,heuristic optimization ,high quality sub-optimal solutions ,Management information systems ,T58.6-58.62 - Abstract
Berth Allocation Problem incorporates some of the most important decisions that have to be made in order to achieve maximum efficiency in a port. Terminal manager of a port has to assign incoming vessels to the available berths, which need to be loaded/unloaded in such a way that some objective function is optimized. It is well known that even simpler variants of Berth Allocation Problem are NP-hard, and thus, metaheuristic approaches are more convenient than exact methods since they provide high quality solutions in reasonable computational time. Metaheuristics are general frameworks used to build heuristic algorithms for hard optimization problems. In this paper, an overview of promising and widely used metaheuristic methods in solving different variants of Berth Allocation Problem is presented.
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- 2017
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11. Combinatorial approach to exactly solving discrete and hybrid berth allocation problem
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Kordić, Stevan, Davidović, Tatjana, Kovač, Nataša, and Dragović, Branislav
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- 2016
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12. An Analysis of Hull Structure Plating Failures Due to Corrosion.
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Ivošević, Špiro and Kovač, Nataša
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- 2023
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13. Hybrid LSTM Model to Predict the Level of Air Pollution in Montenegro.
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Ratković, Kruna, Kovač, Nataša, and Simeunović, Marko
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AIR pollution ,SCIENTIFIC literature ,AIR quality indexes ,MACHINE learning ,SUPPORT vector machines ,STATISTICAL learning - Abstract
Air pollution is a critical environmental concern that poses significant health risks and affects multiple aspects of human life. ML algorithms provide promising results for air pollution prediction. In the existing scientific literature, Long Short-Term Memory (LSTM) predictive models, as well as their combination with other statistical and machine learning approaches, have been utilized for air pollution prediction. However, these combined algorithms may not always provide suitable results due to the stochastic nature of the factors that influence air pollution, improper hyperparameter configurations, or inadequate datasets and data characterized by great variability and extreme dispersion. The focus of this paper is applying and comparing the performance of Support Vector Machine and hybrid LSTM regression models for air pollution prediction. To identify optimal hyperparameters for the LSTM model, a hybridization with the Genetic Algorithm is proposed. To mitigate the risk of overfitting, the bagging technique is employed on the best LSTM model. The proposed predicitive model aims to determine the Common Air Quality Index level for the next hour in Niksic, Montenegro. With the hybridization of the LSTM algorithm and by applying the bagging technique, our approach aims to significantly enhance the accuracy and reliability of hourly air pollution prediction. The major contribution of this paper is in the application of advanced machine learning analysis and the combination of the LSTM, Genetic Algorithm, and bagging techniques, which have not been previously employed in the analysis of air pollution in Montenegro. The proposed model will be made available to interested management structures, local governments, national entities, or other relevant institutions, empowering them to make effective pollution level predictions and take appropriate measures. [ABSTRACT FROM AUTHOR]
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- 2023
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14. Remimazolam: sigurnost i zadovoljstvo bolesnika za proceduralnu sedaciju.
- Author
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Škrtić, Matteo, Lijović, Lada, Kovač, Nataša, Pažur, Iva, Bodulica, Bruna, Periša, Nikola, Ožegić, Ognjen, Vučić, Marinko, and Radočaj, Tomislav
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INTRAVENOUS anesthetics ,MOLECULAR structure ,MIDAZOLAM ,CLINICAL trials ,BENZODIAZEPINES ,SUCCESS - Abstract
Copyright of Lijecnicki Vjesnik is the property of Croatian Medical Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2023
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15. Povijest neuroanestezije.
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Murselović, Tamara and Kovač, Nataša
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The development of neuroanesthesia is inextricably linked with the development of neurosurgery. The realisation that neuroanesthesia has its specifics, due to very nature of neurosurgery, as a separate field of anesthesia, evolved at the turn of the 19th and 20th centuries. Only with the advencement of technology and science, especially in the second half of the 20th century, did neuroanesthesia reach its full potential. The clinical profession has gone from realizing that physiological parameters (pulse and pressure) should be continuously monitored and recorded thanks to dr. Harvey Cushing, to monitoring the effects of anesthestics on EEG, intracranial pressure, cerebral blod flow, and brain metabolism. Thanks to a nummber of top experts, such as Albert Faulconer, John Mitchenfelder, James Cottrel and Roy Cucchiara, neuroanesthesia has become a subspeciality within anesthesiology,with its societies, its journals and professional gartherings. [ABSTRACT FROM AUTHOR]
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- 2023
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16. On the exact analytical formula for dimensionless injection rate in CO2 storage based on Special Trans Functions Theory.
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Perovich, Slavica M and Kovač, Nataša
- Abstract
In this article, Special Trans Functions Theory (STFT) is used to obtain exact solutions of the transcendental equation that describes Dimensionless Injection Rate (DIR) for CO 2 storage. The obtained results were compared with DIR values calculated by a sequential asymptotic formula (SAF) based on the Lambert W function. The proposed exact analytical approach to determining DIR solutions implies considerable qualitative improvement compared to the conventional analytical and numerical methods. Determining STFT DIR solution for CO 2 storage is novel and precise, while the computations are simple, practical and do not require significant computation time. Note that the formulas derived within STFT in applied physics and engineering domains are characterized by structural robustness and complexity. It is a kind of “genetic characteristic” of STFT formulas, which does not affect the efficiency and simplicity of their applications. This paper additionally analyzes the importance of choosing an exact analytical solution for transcendent functional equations that describe the phenomenon of CO 2 storage, since these above-mentioned nonlinear forms describe many other significantly different physical phenomena. This implies the generalization of STF Theory. [ABSTRACT FROM AUTHOR]
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- 2022
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17. Evaluation of the Corrosion Depth of Double Bottom Longitudinal Girder on Aging Bulk Carriers.
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Ivošević, Špiro, Kovač, Nataša, Momčilović, Nikola, and Vukelić, Goran
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OIL storage tanks ,BALLAST water ,GIRDERS ,WATER pollution ,IRON & steel plates - Abstract
The longitudinal girder (LG) between fuel oil tanks (FOT) and water ballast tanks in the double bottoms of ships represent critical structural parts whose watertight nature could be harmed by corrosion, thus, causing the pollution of water ballast tanks and adjacent areas. The new common structural rules (CSR) define the minimum thickness values of structural elements and corrosion margins. The assessment of the deviations from the prescribed values during ship operation could optimize the prescribed criteria. Assuming that corrosive processes begin after four years of operation, the paper analyzes a linear model that describes the percentage of plate wear as a function of the built-in thickness of LG of FOT. The research included 20 ships and provided the database for 1918 corrosion depth values. The gauging records included the average values of the original thickness of steel plates grouped in three intervals (11–13 mm, 13–15 mm, 15–18 mm). Based on the difference between the built-in and subsequently measured values, the paper analyzes the percentage of thickness reduction due to corrosion, concerning the original plate thickness. The findings of the research should facilitate the optimization of corrosion margins and prevent potential structural collapse and pollution. [ABSTRACT FROM AUTHOR]
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- 2022
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18. A Nonlinear Probabilistic Pitting Corrosion Model of Ni–Ti Alloy Immersed in Shallow Seawater.
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Ivošević, Špiro, Vastag, Gyöngyi, Kovač, Nataša, Majerič, Peter, and Rudolf, Rebeka
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ELECTROLYTIC corrosion ,SEAWATER ,PITTING corrosion ,CONTINUOUS casting ,ALLOYS ,SOIL corrosion ,ALLOY analysis - Abstract
The degradation of metal materials in a marine environment represents the consequence of the electrochemical corrosion of metals under the influence of the environment. The application of new materials in the maritime industry requires experimental, real-world research on the form of corrosive damage and the intensity of the corrosion. This paper analyses the pitting corrosion of a rod-shaped nickel–titanium (Ni–Ti) alloy that was produced by means of the continuous casting method. In total, three samples were posted in a real seawater environment and analysed after 6, 12, and 18 months. Pits were detected on the Ni–Ti alloy after 18 months of exposure to the marine environment. The database on pitting corrosion was created by measuring depth in mm, which was performed by means of a nonlinear method, and by the generation of an artificial database of a total of 120, gauged in critical pit areas. The data were obtained by the application of a nonlinear model, and under the assumption that corrosion starts after 12 months of exposure in the corrosive marine environment. The EDX analysis of the Ni–Ti alloy composition inside the pits and on the edges of the pits indicated that the corrosion process in the hole of the pit occurs due to the degradation of the Ni. [ABSTRACT FROM AUTHOR]
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- 2022
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19. Corrosion of NiTiDiscs in Different Seawater Environments.
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Pješčić-Šćepanović, Jelena, Vastag, Gyöngyi, Ivošević, Špiro, Kovač, Nataša, and Rudolf, Rebeka
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SEAWATER ,PRINCIPAL components analysis ,CLUSTER analysis (Statistics) ,X-ray fluorescence ,AMBIENCE (Environment) - Abstract
This paper gives an approach to the corrosion resistance analysis and changes in the chemical composition of anNiTi alloy in the shape of a disc, depending on different real seawater environments. The NiTi discs were analysed after 6 months of exposure in real seawater environments: the atmosphere, a tidal zone, and seawater. The corrosion tests showed that the highest corrosion rate for the discs is in seawater because this had the highest value of current density, and the initial disc had the most negative potential. Measuring the chemical composition of the discs using inductively coupled plasma and X-ray fluorescence before the experiment and semiquantitative analysis after the experiment showed the chemical composition after 6 months of exposure. Furthermore, the applied principal component analysis and cluster analysis revealed the influence of the different environments on the changes in the chemical composition of the discs. Cluster analysis detected small differences between the similar corrosive influences of the analysed types of environments during the period of exposure. The obtained results confirm that PCA can detect subtle quantitative differences among the corrosive influences of the types of marine environments, although the examined corrosive influences are quite similar. The applied chemometric methods (CA and PCA) are, therefore, sensitive enough to register the existence of slight differences among corrosive environmental influences on the analysed NiTi SMA. [ABSTRACT FROM AUTHOR]
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- 2022
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20. The Analyses of the Rate of Pitting Corrosion of a NiTi Rod in a Natural Marine Environment.
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Ivošević, Špiro, Kovač, Nataša, Vastag, Gyöngyi, Majerič, Peter, and Rudolf, Rebeka
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PITTING corrosion , *NICKEL-titanium alloys , *SOIL corrosion , *CONTINUOUS casting , *ULTRASONIC equipment , *SCANNING electron microscopes , *SHAPE memory alloys - Abstract
The analysis of the behaviour of new materials in the natural environment is important for their application and commercial use. In order to explore the application of Shape Memory Alloys in the Maritime industry, this research focuses on the corrosive behaviour of the NiTi rod that was produced by means of a continuous casting process. The experiment included three samples of NiTi rods that were exposed to the marine environment for 6, 12 and 18 months at a depth of 3 metres below the surface. The morphological and chemical changes were analysed separately during the experiment. Ultrasonic thickness equipment and the Scanning Electron Microscope (SEM) technique were used for the tests that determined the corrosion rates and detected pitting. The changes in the chemical composition of the NiTi rod were investigated by means of an Energy Dispersive X-ray (EDX) analysis, in order to define the pitting behaviour of the rod's surfaces during its exposure to seawater. The obtained research results prove that the rate of pitting corrosion follows a progressive curve - the minimum value of corrosion rate equalled 0.04 mm/month, while the maximum value was 0.12 mm/month. [ABSTRACT FROM AUTHOR]
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- 2022
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21. Statistical Approach to the Analysis of the Corrosive Behaviour of NiTi Alloys under the Influence of Different Seawater Environments.
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Kovač, Nataša, Ivošević, Špiro, Vastag, Gyöngyi, Vukelić, Goran, and Rudolf, Rebeka
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NICKEL-titanium alloys ,BEHAVIORAL assessment ,SEAWATER ,ALLOYS ,FOCUSED ion beams - Abstract
Probabilistic models of corrosion rate estimation in the case of two NiTi alloys obtained by different technological processes are analysed in this paper. The depth of corrosion was measured by focused ion beam analysis on a metal surface that was not protected by an anti-corrosion coating. The samples were exposed to the influence of three different seawater environments, and empirical data were obtained in a systematic measurement procedure after 6, 12 and 18 months. Assuming that corrosion processes begin immediately after exposure of the samples to the influence of the seawater environment, and observing the corrosion rate as a random variable affected by various stochastic processes, the formed standard linear corrosion model was analysed by a statistical approach. The three best-fitted three-parameter distributions which can describe the changes in the corrosion rate for NiTi alloys exposed to the influence of the seawater environment adequately were obtained by fitting the continuous theoretical distributions. Adequate statistical tests showed similarities and differences in the behaviour of the two observed NiTi alloys from the point of view of corrosion processes caused by air, tide and sea. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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22. THE RELIABILITY OF WATERTIGHT LONGITUDINAL GIRDERS OF FUEL TANKS ON AGING BULK CARRIERS.
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Ivošević, Špiro and Kovač, Nataša
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FUEL tanks ,STRUCTURAL plates ,PLATE girders ,GIRDERS ,STRUCTURAL reliability - Abstract
During the exploitation of bulk carriers, the condition of structural elements and areas depends on the type of the cargo transported, operational conditions and maintenance systems. Corrosion significantly accelerates the aging of metal plates and girders thus causing the deterioration of steel surfaces, which consequently reduces the reliability of structural elements, areas and ships in general. The damage to metal structures can impair the stability of a ship, reduce longitudinal strength, cause the ingress of water into the hull as well as environmental pollution through fuel spills from the tanks. Therefore, the paper analyzes a part of a double bottom structure based on the available wear data on watertight longitudinal girders of fuel tanks. The research included 25 bulk carriers aged between 5 and 25 with the total of 110 fuel tanks. The reliability analysis of steel plates included the total of 1920 data measured. The allowable wear of structural plate thickness that equals 20% of the original thickness value was determined by the application of the acceptance criteria that were prescribed by classification societies. The calculations of the function of failure density, failure intensity and reliability determined the time when the condition of structural elements deteriorates due to corrosion up to the levels that require extensive maintenance services. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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23. Population-based Metaheuristics for the Dynamic Minimum Cost Hybrid Berth Allocation Problem.
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Kovač, Nataša, Davidović, Tatjana, and Stanimirović, Zorica
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METAHEURISTIC algorithms , *MIXED integer linear programming , *CONTAINER terminals , *DECISION support systems , *GENETIC algorithms , *STATISTICS - Abstract
This study considers the Dynamic Minimum Cost Hybrid Berth Allocation Problem (DMCHBAP) with fixed handling times of vessels. The objective function to be minimized consists of three components: costs of positioning, waiting, and tardiness of completion for all vessels. A mathematical formulation of DMCHBAP, based on Mixed Integer Linear Programming (MILP), is proposed and used within the framework of commercial CPLEX 12.3 solver. As the speed of finding high-quality solutions is of crucial importance for an efficient and reliable decision support system in container terminal, two population-based metaheuristic approaches to DMCHBAP are proposed: combined Genetic Algorithm (cGA) and improvement-based Bee Colony Optimization (BCOi). Both cGA and BCOi are evaluated and compared against each other and against state-of-the-art solution methods for DMCHBAP on five sets of problem instances. The conducted computational experiments and statistical analysis indicate that population-based metaheuristic methods represent promising approaches for DMCHBAP and similar problems in maritime transportation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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24. TUBULOINTERSTITIAL NEPHRITIS AND UVEITIS SYNDROME – A CASE REPORT.
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KOVAČ, Nataša, KOVAČ, Maja, LUKIĆ, Maja SAMARDŽIĆ, STAJIĆ, Nataša, and MILOŠEVIĆ, Biljana
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NEPHRITIS , *IRIDOCYCLITIS , *CHRONIC kidney failure , *UVEITIS , *RESPIRATORY infections , *SYNDROMES , *RENAL biopsy - Abstract
Introduction. Tubulointerstitial nephritis and uveitis syndrome is a rare oculo-renal disease characterized by the presence of bilateral, anterior uveitis and tubulointerstitial nephritis. The pathogenesis of this disease is still not completely clear. It is associated with prior drug use, infections and autoimmune diseases. The involvement of the cellular and humoral immune responses and genetic predisposition to the development of this syndrome are frequently mentioned in the literature. In a certain number of cases, despite extensive diagnostics, the cause remains unknown (idiopathic tubulointerstitial nephritis and uveitis syndrome). Case Report. A fifteen-year-old female patient was admitted to the Department of Nephrology due to complaints of headache in the temples that occasionally occurred in the previous months. Three days before admission, the patient presented with symptoms of upper respiratory tract infection and subfebrile temperature (to 37.8°C). Laboratory test results revealed the development of acute tubulointerstitial nephritis, and in the fifth week of the disease, bilateral anterior uveitis was detected. The diagnosis was confirmed by percutaneous kidney biopsy. Systemic and local corticosteroid therapy was introduced, and after a month it resulted in gradual normalization of kidney function, proteinuria reduction and withdrawal of the ophthalmic symptoms. Conclusion. Due to the fact that kidney damage is often self-limited and that uveitis tends to be recurrent, there is a high probability of untimely diagnosis. Early recognition, detection of potential causes and initiation of treatment, are crucial in the prevention of disease progression and development of chronic sequelae such as chronic renal failure and chronic uveitis. [ABSTRACT FROM AUTHOR]
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- 2021
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25. REGIONAL ANESTHESIA FOR NEUROSURGERY.
- Author
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Tonković, Dinko, Bandić Pavlović, Daniela, Baronica, Robert, Virag, Igor, Miklić Bublić, Martina, Kovač, Nataša, and Željko, Drvar
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- 2019
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26. Variable Neighborhood Search Methods for the Dynamic Minimum Cost Hybrid Berth Allocation Problem.
- Author
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Kovač, Nataša, Davidović, Tatjana, and Stanimirović, Zorica
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HYBRID systems ,ASSIGNMENT problems (Programming) ,DECISION support systems ,METAHEURISTIC algorithms ,COMPUTATIONAL complexity - Abstract
This study considers the Dynamic Minimum Cost Hybrid Berth Allocation Problem (DMCHBAP) with fixed handling times of vessels. The objective function to be minimized consists of three components: the costs of positioning, waiting, and tardiness of completion for all vessels. Having in mind that the speed of finding high-quality solutions is of crucial importance for designing an efficient and reliable decision support system in container terminal, metaheuristic methods represent the natural choice to deal with DMCHBAP. Four variants of Variable Neighborhood Search (VNS) metaheuristic are designed for DMCHBAP. All four proposed VNS methods are evaluated on four classes of randomly generated instances with respect to solution quality and running times. The conducted computational analysis indicates that all four VNS-based methods represent promising solution approaches to DMCHBAP and similar problems in maritime transportation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
27. AN APPROACH TO THE PROBABILISTIC CORROSION RATE ESTIMATION MODEL FOR INNER BOTTOM PLATES OF BULK CARRIERS.
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Ivošević, Špiro, Meštrović, Romeo, and Kovač, Nataša
- Subjects
CARRIERS ,CORROSION & anti-corrosives ,SHIP hull fouling - Abstract
This paper gives an approach to the probabilistic corrosion rate estimation model for inner bottom plates of bulk carriers. Firstly, by using the data from thickness measurements for inner bottom plates for considered 25 bulk carriers, the related best fitted linear model for the corrosion wastage is obtained as a function of ship's age. In this model it is assumed that life of coating is 4 years. The obtained related corrosion rate is equal to 0.135474 mm/year. Notice that the obtained linear model is a particular case of a power model proposed in some earlier investigations. In view of the fact that the corrosion rate of ship hull structures is influenced by many factors, many of an uncertain nature, in recent studies several authors investigated a probabilistic model as more appropriate to describe the expected corrosion. Motivated by these investigations, and using 2926 thickness measurements for corrosion wastage of inner bottom plates of considered 38 special ships surveys, this paper examines the cumulative density function for the corrosion rate c
1 involved in the mentioned linear model, and considered here as a continuous random variable. The obtained statistical, numerical and graphical results show that the logistic distribution or normal distribution would be well appropriate for the probabilistic corrosion rate estimation model for inner bottom plates of bulk carriers. It is believed that this fact will be confirmed with greater statistical reliability in our future investigations including many more data collected on the considered corrosion. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
28. SURVEY METAHEURISTIC APPROACHES FOR THE BERTH ALLOCATION PROBLEM.
- Author
-
KOVAČ, Nataša
- Subjects
ASSIGNMENT problems (Programming) ,METAHEURISTIC algorithms ,CONTAINER terminals - Abstract
Berth Allocation Problem incorporates some of the most important decisions that have to be made in order to achieve maximum efficiency in a port. Terminal manager of a port has to assign incoming vessels to the available berths, which need to be loaded/unloaded in such a way that some objective function is optimized. It is well known that even simpler variants of Berth Allocation Problem are NP-hard, and thus, metaheuristic approaches are more convenient than exact methods since they provide high quality solutions in reasonable computational time. Metaheuristics are general frameworks used to build heuristic algorithms for hard optimization problems. In this paper, an overview of promising and widely used metaheuristic methods in solving different variants of Berth Allocation Problem is presented. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
29. Clinical significance of intraabdominal pressure and abdominal perfusion pressure in patients with acute abdominal syndrome.
- Author
-
Kovač, Nataša, Širanović, Mladen, and Mazul-Sunko, Branka
- Subjects
- *
PERFUSION , *ACUTE abdomen , *ABDOMINAL diseases , *URINARY organs , *PERITONITIS , *PATIENTS - Abstract
Elevated intraabdominal pressure (IAP) has been claimed to play a role in abdominal compartment syndrome. We assessed the correlation between the values of IAP, abdominal perfusion pressure (APP) and clinical scoring systems including SIRS, MODS and APACHE II and the patients' survival rate in patients admitted to the ICU with acute abdomen due to ileus, intestinal perforation, peritonitis and trauma. We measured IAP and APP in 50 surgical patients. In this study the IAP was measured in a non-invasive manner via urinary bladder pressure. The APP was calculated as the difference between mean arterial pressure and IAP values. A significantly higher IAP was found in the non-survivors' group in comparison with the survivors' group. On the other hand, the APP inversely correlated with disease severity scores including SIRS, MODS and APACHE II, whereas IAP values did not show any correlation to these clinical parameters. These findings suggest that IAP and APP may be useful tools in the clinical evaluation of patients with acute abdomen. [ABSTRACT FROM AUTHOR]
- Published
- 2007
30. A Probabilistic Method for Estimating the Influence of Corrosion on the CuAlNi Shape Memory Alloy in Different Marine Environments.
- Author
-
Ivošević, Špiro, Kovač, Nataša, Vastag, Gyöngyi, Majerič, Peter, Rudolf, Rebeka, and Figueras, Albert
- Subjects
SHAPE memory alloys ,PROBABILITY density function ,FOCUSED ion beams ,RANDOM variables ,PRINCIPAL components analysis - Abstract
This paper gives an approach to the probabilistic percent corrosion depth estimation model for the CuAlNi Shape Memory Alloy (SMA) in different marine environments. Real testing was performed for validation of the theoretical model, where CuAlNi SMAs were exposed to 6 and 12 months in different seawater environments. Focus Ion Beam (FIB) analysis was used to measure the real corrosion depth on the surfaces of tested samples. A statistical approach to the investigation of the corrosion rate of CuAlNi SMA is given, where the corrosion rate is observed as a continuous random variable described by a linear corrosion model, with the assumption that corrosion starts immediately upon alloy surfaces being exposed to the influences of the marine environment. The three best-fitted two-parameter distributions for estimating the cumulative density function and the probability density function of the random variable were obtained by applying adequate statistical tests. Furthermore, using EDX analyses, we identified the chemical composition of the corroded materials, and with the help of Principal Component Analyses, we determined which corrosion environment had the most dominant influence on the corrosion process. The research results indicated that the changeable environment in the tides had a more heterogenic chemical content, which accelerated the corrosion rate. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
31. A Probabilistic Method for Estimating the Percentage of Corrosion Depth on the Inner Bottom Plates of Aging Bulk Carriers.
- Author
-
Ivošević, Špiro, Meštrović, Romeo, and Kovač, Nataša
- Subjects
OIL storage tanks ,PROBABILITY density function ,RANDOM variables ,PERCENTILES ,CORROSION fatigue ,PROBABILISTIC number theory ,PLATING - Abstract
This paper presents an approach for the model estimating the probabilistic percent corrosion depth for inner bottom plates of fuel oil tanks located in the double bottom of aging bulk carriers. Assuming that corrosion begins after four years of exploitation, a statistical approach to investigations on the ratio of the corrosion rate and the average initial inner bottom plate's thickness of considered bulk carriers is given. We consider this ratio to be a random variable since it is included in the usual linear corrosion model. By applying adequate statistical tests to the available empirical dataset, three best fitted three-parameter distributions for estimating the cumulative density function and the probability density function of the random variable were obtained. These three distributions were further used to estimate the studied percentage of corrosion depth. Lastly, we present the corresponding numerical and graphical results concerning the obtained statistical and empirical results and give concluding remarks. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
32. Recombinant factor VIIa therapy in a patient on long term anticoagulant treatment with a bleeding and acute subdural hematoma.
- Author
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Kovač, Nataša, Gopčević, Aleksandar, Kovač, Josip, Gaćina, Petar, and Novkoski, Mladen
- Subjects
- *
THERAPEUTICS , *ANTICOAGULANTS , *SUBDURAL hematoma , *HEMATOMA , *WARFARIN , *VITAMIN K - Abstract
In this paper we report on the successful correction of a coagulopathy with activated recombinant factor seven (rFVIIa) therapy which enabled surgical removal of a life threatening subdural hematoma. The severe coagulopathy developed due to long term warfarin therapy, which followed heart valvular reconstruction and replacement. The coagulopathy failed to improve following fresh frozen plasma and vitamin K therapy. Activated recombinant factor VII therapy became the treatment of choice, which enabled the life saving surgical removal of the subdural hematoma. [ABSTRACT FROM AUTHOR]
- Published
- 2007
33. Early complications of percutaneous tracheostomy using the Griggs method.
- Author
-
Širanović, Mladen, Gopčević, Saša, Kelečić, Mijo, Kovač, Nataša, KrikšIć, Valentina, Rode, Bojan, and Vučić, Marinko
- Subjects
- *
TRACHEOTOMY , *AIRWAY (Anatomy) , *TRACHEAL surgery , *INTENSIVE care units , *PATIENTS , *RESPIRATION - Abstract
This article presents our observations and experiences with the Griggs method of percutaneous dilation tracheostomy (PTD). We performed 200 tracheostomies on neurosurgical and surgical patients who needed temporary ventilatory support and protection. Early complications were defined and registered. Frequency of early complications was 22,5%. The majority of complications were minor and improved quickly. Therefore, PTD was shown to be a safe and appropriate technique for patients treated in the intensive care unit (ICU). Unfortunately, lack of standardization and defined criteria deprive the opportunity for good comparisons between the Griggs method and other PTD methods. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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