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Circuits' and in particular DC/DC converters' switching behavior is analyzed in this paper using the equivalent control modeling of the dynamic systems' sliding mode regime. As a representative example and also being one of the0 most complex circuits among DC/DC converters, the Ćuk converter is chosen. It is shown how the converter's behavior in the steady state regime can be studied and analyzed by the linear matrix inequalities based stability conditions for linear dynamic systems with nonlinear sector bounded perturbations. The maximization of the nonlinear sector bound provides a limit for applying the linear ripple approximation in the converter operation analysis. Furthermore, our approach is validated by providing simulation results for two different switching surfaces of practical interest.

Abstract: On 4 May 2022 the InSight seismometer SEIS‐VBB recorded the largest marsquake ever observed, S1222a, with an initial magnitude estimate of 4.6. Understanding the depth and source properties of this event has important implications for the nature of tectonic activity on Mars. Located ∼37° to the southeast of InSight, S1222a is one of the few non‐impact marsquakes that exhibits prominent surface waves. We use waveform modeling of body waves (P and S) and surface waves (Rayleigh and Love) to constrain the focal mechanism, assuming a double‐couple source, and find that S1222a likely resulted from reverse faulting in the crust (source depth near 22 km). We estimate the scalar moment to be 2.5 × 1015–3.5 × 1015 Nm (magnitude MW 4.2–4.3). Our results suggest active compressional tectonics near the dichotomy boundary on Mars, likely due to thermal contraction from planetary cooling.

The extensive integration of distributed renewable energy resources (DRES) can lead to several issues in power grids, particularly in distribution grids, due to their inherent intermittency. This paper presents a stochastic simulation-based approach to estimate the maximum permissible penetration level of DRES and to determine the optimal capacity of centralized battery energy storage systems (BESS) in distribution networks while adhering to technical constraints. The stochastic method creates a wide range of scenarios under various conditions. For each scenario, our proposed approach calculates the maximum allowable penetration level of DRES and the required BESS capacity with different DRES control logics. The maximum allowable penetration level of DRES and the requirements of the BESS capacity are determined by an analysis of various simulation results. This paper’s unique contribution lies in equipping distribution system operators (DSOs) with the ability to compare results and select the most appropriate voltage control and power smoothing methods. This aids in mitigating challenges associated with overvoltage and intermittency issues arising from DRES-generated power, thereby enhancing the overall resilience and reliability of the power grid. Case studies that include four voltage control algorithms and three power smoothing methods demonstrate the universality and effectiveness of the proposed approach.

We present the first observations of seismic waves propagating through the core of Mars. These observations, made using seismic data collected by the InSight geophysical mission, have allowed us to construct the first seismically constrained models for the elastic properties of Mars' core. We observe core-transiting seismic phase SKS from two farside seismic events detected on Mars and measure the travel times of SKS relative to mantle traversing body waves. SKS travels through the core as a compressional wave, providing information about bulk modulus and density. We perform probabilistic inversions using the core-sensitive relative travel times together with gross geophysical data and travel times from other, more proximal, seismic events to seek the equation of state parameters that best describe the liquid iron-alloy core. Our inversions provide constraints on the velocities in Mars' core and are used to develop the first seismically based estimates of its composition. We show that models informed by our SKS data favor a somewhat smaller (median core radius = 1,780 to 1,810 km) and denser (core density = 6.2 to 6.3 g/cm3) core compared to previous estimates, with a P-wave velocity of 4.9 to 5.0 km/s at the core-mantle boundary, with the composition and structure of the mantle as a dominant source of uncertainty. We infer from our models that Mars' core contains a median of 20 to 22 wt% light alloying elements when we consider sulfur, oxygen, carbon, and hydrogen. These data can be used to inform models of planetary accretion, composition, and evolution.

Honey has become a focal point of concern due to the potential presence of pesticide residues originating from agricultural practices. This study undertakes a comprehensive toxicological assessment of pesticide residues in conventional and organic honey, as well as a risk assessment employing estimated daily intakes (EDIs) in the evaluation of the potential risks of these agrochemicals to public health. A total of 200 honey samples originating from conventional and organic producers were collected and analyzed by a Quick Easy Cheap Effective Rugged Safe method (QuEChERS). Analysis of organic honey didn’t detect any residue of investigated pesticides. The most detected pesticides in conventional honey samples were boscalid (0.01 μg/kg), and coumaphos ranging between 0.012 μg/kg to 0.016 μg/kg, respectively. Detected pesticides such as acetamiprid, pyraclostrobin, thiacloprid, and azoxystrobin were under the reporting level (RL). Results obtained by EDI indicated that all investigated honey samples are safe for human consumption. In conclusion, this research contributes to the understanding of the toxicological implications of pesticide residues in both conventional and organic honey consumption. By delineating the potential health hazards associated with each type, this study aims to provide consumers, regulators, and beekeeping industries with valuable insights to make informed decisions that safeguard human health while promoting sustainable agricultural practices.

The deployment of voltage source converters (VSC) to facilitate flexible interconnections between the AC grid, renewable energy system (RES) and Multi-terminal DC (MTDC) grid is on the rise. However, significant challenges exist in exploiting coordinated operations for such AC/VSC-MTDC hybrid power systems. One of the most critical issues is how to achieve the optimal operation of such wide-area systems involving several power entities with as minimal communication burden as possible. To address this issue, an enhanced AC/DC optimal power flow (OPF) is specifically proposed. Firstly, a mixed-integer convex AC/DC OPF model is explicitly formulated to describe the optimal operation of such hybrid power systems. Subsequently, a nested distributed optimization method with double iteration loops is developed to offer optimal system-wide decision-making through a more “thorough” distributed communication architecture. In the outer iteration, the original AC/DC OPF problem is decomposed into several slave problems (SPs) associated with systems (including the AC grid and RESs) and one master problem (MP) associated with the integrated VSC-MTDC grid. Generalized Benders decomposition (GBD) serves to solve the master and slave problems iteratively. Techniques such as multi-cut generation and asynchronous updating are utilized to upgrade the GBD performance of computation efficiency and address communication delays. In the inner iteration, the master problem is continuously decomposed into multiple sub-MPs associated with individual VSCs. The alternating direction method of multipliers (ADMM) is employed to solve these sub-MPs iteratively. Proximal terms and heuristic approaches are embedded to enable parallel computation and handling of integer variables. Numerical experiment results finally validate the effectiveness of the proposed enhanced AC/DC OPF. The constructed AC/DC OPF model exhibits acceptable accuracy in terms of power flow calculation, and the developed nested distributed optimization method showcases decent convergence rate and solution optimality performances.

The performance of existing protection methods for multi-terminal direct current systems depends on the availability and sizes of boundary components. To overcome the limitation, this paper proposes a non-unit DC line protection method based on the normalized backward traveling waves (BTWs) of the 1-mode voltage. Firstly, traveling wave propagation characteristics are analyzed, and a rationalization approach based on vector fitting is proposed. Next, the analytical expressions of normalized BTWs are derived, with the negative correlation between them and fault distance proved. Then, the derivative-free conjugate gradient algorithm is utilized for amplitude fitting and normalization calculation. Finally, a non-unit protection method using the normalized BTWs is developed. The performance is validated for both electromagnetic transient PSCAD/EMTDC and real-time digital RSCAD/RTDS simulation. The results demonstrate that the proposed method can accurately identify faults with various fault resistances and locations without requiring boundary components and high sampling frequencies, and it is robust against noise disturbances.

Aim Despite advancements in the diagnosis, treatment and monitoring of patients with acute coronary syndrome (ACS), morbidity and mortality following ACS remain high. The aim of this study was to actively seek possible predictors of adverse outcomes after ACS aiming to identify high-risk patients promptly.Methods This retrospective cohort study investigated patients with ACS hospitalized at Clinical Centre of the University of Sarajevo from 2019 to 2021. Patients were followed up for a period of 12 months post-discharge to assess major cardiovascular events (MACE) and MACE associated independent predictors. Results. The study included 121 patients, mostly male 102 (84.3%), with a mean age of 60.83±12.61 years; prevalent risk factors were hypertension 94 (77.7%), dyslipidaemia 84 (69.4%), diabetes mellitus 91 (75.2%), active smoking 67 (55.4%) and positive family history of cardiovascular diseases 81 (66.9%). MACE occurred in 33 (27.3%) patients since the initial ACS, and those patients were older (p=0.012), had higher level of creatinine (p

An economical approach for incorporating Battery Energy Storage Systems (BESS) onto DP-2 vessels is presented in this research. The paper deals with developing a Battery Optimization for Optimal Sizing and Throughput Energy Regulation (BOOSTER) framework for putting research findings into practice by optimizing battery size, technology choice and power generation scheduling while considering battery degradation. Twelve battery sizes are analyzed based on three key performance metrics: return on investment, payback period, and years of profitability. A Mixed Integer Linear Programming (MILP) is developed to operate the energy and power management system of the vessel in a fuel and economically efficient manner. The study considers two load profiles of a DP-2 vessel operating near Taiwan and the North Sea. Our findings emphasize the significance of taking battery ownership costs in the form of energy throughput cost and fuel price into account, resulting in a longer battery lifetime and higher return on investment. The research also proposes a BESS operation matrix that provides vessel operators with valuable information on BESS usage for economic benefits. This matrix translates analytics and decision-making into tangible actions that can be implemented in real-time operations. Based on the findings, energy systems may be optimized for a sustainable future, which benefits vessel operators and industry stakeholders.

IntroductionNutritional deficiency among the older adult is a widespread concern, significantly affecting their health. The prevalence of malnutrition increases with age, concurrent health conditions, and the level of care provided. Hospital stays can affect as 90% of the older adult. Malnutrition can hinder efforts to improve health and regain function in individuals undergoing rehabilitation. This study aims to assess the frequency of malnutrition among geriatric rehabilitation patients.Materials and methodsA retrospective quantitative analysis was conducted on 357 patients admitted to the geriatric unit at Lucerne Cantonal Hospital Wolhusen in Switzerland. The patients’ nutritional status was evaluated using the standardized Mini Nutritional Assessment Long Form questionnaire.ResultsThe initial analysis indicated a considerable prevalence of malnutrition among the geriatric population: 31.1% were identified as malnourished (MNA

Abstract: The largest seismic event ever recorded on Mars, with a moment magnitude of 4.7 ± 0.2, is the first event to produce both Love and Rayleigh wave signals. We measured their group velocity dispersion between about 15 and 40 s period and found that no isotropic depth‐dependent velocity model could explain the two types of waves wave simultaneously, likely indicating the presence of seismic anisotropy. Inversions of Love and Rayleigh waves yielded velocity models with horizontally polarized shear waves traveling faster than vertically polarized shear waves in the top 10–25 km. We discuss the possible origins of this signal, including the preferred orientation of anisotropic crystals due to shear deformation, alignment of cracks, layered intrusions due to an impact, horizontal layering due to the presence of a large‐scale sediment layer on top of the crust, and alternation of sedimentation and basalt layers deposits due to large volcanic eruptions.

The most distant marsquake recorded so far by the InSight seismometer occurred at an epicentral distance of 146.3 ± 6.9o, close to the western end of Valles Marineris. On the seismogram of this event, we have identified seismic wave precursors, i.e., underside reflections off a subsurface discontinuity halfway between the marsquake and the instrument, which directly constrain the crustal structure away (about 4100-4500 km) from the InSight landing site. Here we show that the Martian crust at the bounce point between the lander and the marsquake is characterized by a discontinuity at about 20 km depth, similar to the second (deeper) intra-crustal interface seen beneath the InSight landing site. We propose that this 20-km interface, first discovered beneath the lander, is not a local geological structure but likely a regional or global feature, and is consistent with a transition from porous to non-porous Martian crustal materials.

We detected surface waves from two meteorite impacts on Mars. By measuring group velocity dispersion along the impact-lander path, we obtained a direct constraint on crustal structure away from the InSight lander. The crust north of the equatorial dichotomy had a shear wave velocity of approximately 3.2 kilometers per second in the 5- to 30-kilometer depth range, with little depth variation. This implies a higher crustal density than inferred beneath the lander, suggesting either compositional differences or reduced porosity in the volcanic areas traversed by the surface waves. The lower velocities and the crustal layering observed beneath the landing site down to a 10-kilometer depth are not a global feature. Structural variations revealed by surface waves hold implications for models of the formation and thickness of the martian crust.

Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. Mineral physics predicts that Mars' deep mantle is demarcated by a seismic discontinuity arising from the pressure-induced phase transformation of the mineral olivine to its higher-pressure polymorphs, making the depth of this boundary sensitive to both mantle temperature and composition. Here, we report on the seismic detection of a midmantle discontinuity using the data collected by NASA's InSight Mission to Mars that matches the expected depth and sharpness of the postolivine transition. In five teleseismic events, we observed triplicated P and S waves and constrained the depth of this discontinuity to be 1,006 [Formula: see text] 40 km by modeling the triplicated waveforms. From this depth range, we infer a mantle potential temperature of 1,605 [Formula: see text] 100 K, a result consistent with a crust that is 10 to 15 times more enriched in heat-producing elements than the underlying mantle. Our waveform fits to the data indicate a broad gradient across the boundary, implying that the Martian mantle is more enriched in iron compared to Earth. Through modeling of thermochemical evolution of Mars, we observe that only two out of the five proposed composition models are compatible with the observed boundary depth. Our geodynamic simulations suggest that the Martian mantle was relatively cold 4.5 Gyr ago (1,720 to 1,860 K) and are consistent with a present-day surface heat flow of 21 to 24 mW/m2.

Sustainable and resilient systems within the food industry play a key role in global growth and development. In recent years, negative effects such as drought caused by climate change, destructive natural disasters, and destruction of biodiversity and natural resource erosion, agricultural migration, aging agricultural population, and global epidemics have deepened the environmental concerns. Apart from the negative effects on the food supply, pressure on the demand side is created by the growing population, which makes it necessary to create a new agrarian policy. Technological development has affected agriculture and agricultural production systems. One of the most prominent approaches is the integration of a new generation of digital technologies into the agricultural system, ensuring maximum benefit from information and data. Digitalization and the use of digital data have fundamentally transformed the agro-food system. The aim of this paper is present in a systematic view the agricultural digital transformation in the Agriculture 4.0, in the framework of sustainable development of agriculture. The aforementioned imposes sustainable agriculture by adequate agricultural policy instruments.

The performance of geothermal heat extraction in shallow aquifers depends on both Borehole Heat Exchanger (BHE) and soil or aquifer properties. In this work, an analysis of the thermal yield of a shallow geothermal reservoir was made numerically with the finite element method used to simulate heat and mass transfer in the three-dimensional reservoir. The main parameters for analysis which have been considered are the geometry and physical parameters of the BHE and grout, as well as aquifer matrix and groundwater fluid. Physical parameters are thermal conductivity, flow conductivity, expansion coefficient, porosity, volumetric heat capacity, anisotropy and dispersivity. The numerical tests have been performed in single BHE line source configuration representing numerically modelled thermal response test for the estimation of sustainable heat extraction. The domain size was a 100x100 meter rectangle with a depth of 200 meters. Three main lithological configurations have been modelled: gravel aquifer with low and high convection of groundwater fluid, as well as a shallow geothermal reservoir dominated by clay material without convection. For selected cases, the analysis for temporal and spatial discretization was also made. Three-dimensional transient modelling was made in FEFLOW® software with pre- and post-processing done in user-defined Python scripts. The results show the most influential parameters to be considered when setting up the real case simulation of geothermal heating and cooling, as well as optimal temporal and spatial discretization set-up with respect to expected thermal gradients in the reservoir.

The present study investigated the volatile constituents of Cymbopogon citratus (lemongrass) grown in a greenhouse environment in Serbia, marking the first commercial cultivation of the plant for essential oil production in the region. The essential oils and hydrolates obtained through steam distillation were analyzed via gas chromatography–mass spectrometry (GC-MS), and the resulting chemical data were further processed using chemometric methods. This study applied quantitative structure retention relationship (QSRR) analysis, employing molecular descriptors (MDs) and artificial neural networks (ANNs) to predict the retention indices (RIs) of the compounds. A genetic algorithm (GA) was used to select the most relevant MDs for this predictive modeling. A total of 29 compounds were annotated in the essential oils, with geranial and neral being the dominant components, while 37 compounds were detected in the hydrolates. The ANN models effectively predicted the RIs of both essential oils and hydrolates, demonstrating high statistical accuracy and low prediction errors. This research offers valuable insights into the chemical profile of lemongrass cultivated in temperate conditions and advances QSRR modeling for essential oil analysis.

This study aimed to ascertain the differences in the nutritional composition of maize grains by analysing their lipid, protein, fatty acid, triacylglycerol, and sugar content before and after undergoing an accelerated aging (AA) test. Additionally, phytochemicals (total pigments, phenolics and flavonoids), as well as antioxidant potential of maize grains were evaluated through ABTS•+ scavenging capacity and ferric reducing power (FRP) assays. Maize was cultivated in Serbia during the 2017 season, employing two growing systems (conventional and organic). Although minimal differences were observed in protein and lipid content, the grains proved to be an excellent source of polyunsaturated fatty acids and triacylglycerols with ECN44 fraction being predominant. The total soluble sugar content was low, while starch content was significantly higher. HPLC analysis confirmed a considerably higher prevalence of non-reducing disaccharides compared to reducing disaccharides. Maize grains emerged as a substantial source of chlorophyll a (0.53-4.38 µg/g DW), phenolics (1498.9-1931.3 mg FAE/kg DW), and flavonoids (85.7-381.9 mg QE/kg DW). All tested extracts exhibited satisfactory abilities to neutralize free ABTS•+. The FRP assay revealed a significantly higher ability to reduce Fe3+-ions in conventionally produced grains. According to the Blunt-Altman test, all analysed parameters showed considerable similarity, except for chlorophylls a and b. Principal component analysis (PCA) revealed that grains exposed to the AA test were mainly separated based on chlorophyll a, C20:0, C18:1n-9, MUFA, carotenoids, lipids content. Conversely, conventional untreated grains were primarily distinguished by their pentose, hexose and chlorophyll b content, while in the case of organic samples, disaccharides (both reducing and non-reducing) and soluble sugars were the main differentiating factors. The present preliminary study can serve as foundational research for future investigations aimed at comprehending alterations in nutrients and phytochemicals induced by accelerated aging tests. However, it should be supplemented and expanded upon by subsequent studies in the future.

Digital technologies permeate almost all spheres of human lives in contemporary times, affecting a number of aspects of people’s lives. Such is the case with cultural rights as well, especially in the cases of certain groups. The paper is focused on the impact of digital technologies on these rights of d/Deaf and hard-of-hearing people. The theoretical framework of the paper defines the concepts of culture and general and specific cultural rights, as well as the labels of deaf, Deaf and hard-of-hearing. Then, an overview of relevant digital technologies is provided, with an evaluation of the impact they have on these cultural rights. Finally, possible strategies for improvement are broadly defined, and a conclusion is provided, summarizing the results of the research done.

The Seismic Experiment for Interior Structure (SEIS) of the InSight mission to Mars, has been providing direct information on Martian interior structure and dynamics of that planet since it landed. Compared to seismic recordings on Earth, ground motion measurements acquired by SEIS on Mars are made under dramatically different ambient noise conditions, but include idiosyncratic signals that arise from coupling between different InSight sensors and spacecraft components. This work is to synthesize what is known about these signal types, illustrate how they can manifest in waveforms and noise correlations, and present pitfalls in structural interpretations based on standard seismic analysis methods. We show that glitches, a type of prominent transient signal, can produce artifacts in ambient noise correlations. Sustained signals that vary in frequency, such as lander modes which are affected by variations in temperature and wind conditions over the course of the Martian Sol, can also contaminate ambient noise results. Therefore, both types of signals have the potential to bias interpretation in terms of subsurface layering. We illustrate that signal processing in the presence of identified nonseismic signals must be informed by an understanding of the underlying physical processes in order for high fidelity waveforms of ground motion to be extracted. While the origins of most idiosyncratic signals are well understood, the 2.4 Hz resonance remains debated and the literature does not contain an explanation of its fine spectral structure. Even though the selection of idiosyncratic signal types discussed in this paper may not be exhaustive, we provide guidance on best practices for enhancing the robustness of structural interpretations.

The requirements of the modern business environment have initiated the emergence of a new paradigm, which finds its starting point in the fact that intellectual property is a crucial success variable of every company, which has stimulated numerous researches in this area. Rapid and extensive changes in all domains of business require companies to be flexible and ready to respond to given changes in accordance with the specificity of the concrete situation. In such conditions, companies must create their own knowledge base and have valuable and competent employees who should be properly managed. Human resources who possess adequate knowledge, who have mastered specific skills and competencies, who are dedicated to teamwork, innovation and permanent improvement form the base of intellectual capital. The aim of the paper is to enrich the previous research model in order to analyse the interconnection of intellectual capital components and business performance of Serbian companies in the ICT sector.

Background and Objectives. In emergency departments, chest pain is a common concern, highlighting the critical importance of distinguishing between acute coronary syndrome and other potential causes. Our research aimed to introduce and implement the HEAR score, specifically, in remote emergency outposts in Bosnia and Herzegovina. Materials and Methods. This follow-up study conducted a retrospective analysis of a prospective cohort consisting of patients who were admitted to the remote emergency medicine outposts in Canton Sarajevo and Zenica from 1 November to 31 December 2023. Results. This study comprised 103 (12.9%) patients with low-risk HEAR scores and 338 (83.8%) with high-risk HEAR scores, primarily female (221, 56.9%), with a mean age of 63.5 ± 11.2). Patients with low-risk HEAR scores were significantly younger (50.5 ± 15.6 vs. 65.9 ± 12.1), had fewer smokers (p < 0.05), and exhibited a lower incidence of cardiovascular risk factors compared to those with high-risk HEAR scores. Low-risk HEAR score for prediction of AMI had a sensitivity of 97.1% (95% CI 89.9–99.6%); specificity of 27.3% (95% CI 22.8–32.1%); PPV of 19.82% (95% CI 18.67–21.03%), and NPV of 98.08% (95% CI 92.80–99.51%). Within 30 days of the admission to the emergency department outpost, out of all 441 patients, 100 (22.7%) were diagnosed with MACE, with AMI 69 (15.6%), 3 deaths (0.7%), 6 (1.4%) had a CABG, and 22 (4.9%) underwent PCI. A low-risk HEAR score had a sensitivity of 97.0% (95% CI 91.7–99.4%) and specificity of 27.3% (95% CI 22.8–32.1%); PPV of 25.5% (95% CI 25.59–28.37%); NPV of 97.14% (95% CI 91.68–99.06%) for 30-day MACE. Conclusions. In conclusion, the outcomes of this study align with existing research, underscoring the effectiveness of the HEAR score in risk stratification for patients with chest pain. In practical terms, the implementation of the HEAR score in clinical decision-making processes holds significant promise.

News of Carter’s discovery in the Valley of Kings was first transmitted by magazines and daily papers in the Kingdom of Serbs, Croats and Slovenes in late 1922, but the finds from Tutankhamun’s tomb continued to draw the public’s attention in the decades to come. A large number of newspaper articles from the time are dedicated to not only Tutankhamun, but also the different manifestations of Egyptomania and Tutmania, from the “curse of the pharaoh”, all the way to fashion inspired by Ancient Egypt. On the other hand, the interwar press reminds us of the efforts of local experts, such as Nikola Vulić and Luka Zrnić, to popularize and present modern archaeological research to the wider audience. This is why all of these diverse testimonies must be observed as a whole to better grasp the connection between science, the media and the public which, in the case of Tutankhamun’s tomb, lead to the creation of a public image within which scientific facts got inextricably mixed up with fantasy, thereby influencing not only the imagination of readers, but also numerous travelers and adventurers to set off for Egypt and directly encounter the legacy of Ancient Egypt.