SCIDAR - Дигитална архива Универзитета у Крагујевцу
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AUTOMATIC CONTROL AND ARTIFICIAL INTELLIGENCE: DEVICE FOR CONTINUOUS CHLORINE RESIDUAL MEASUREMENT
Full text linkBacteriologically safe water is crucial for potable and food production, which is obtained using disinfection. Disinfectants must be broad-spectrum, act swiftly, withstand organic matter, maintain stability across pH levels, be non-toxic, minimally corrosive, and pleasant-smelling. Precise dosing is vital, typically achieved via automated membrane dosing pumps, and is ensured by measuring residual chlorine post-disinfection. This paper introduces devices utilising amperometric electrodes to maintain active chlorine levels of 0.2 to 0.5 mg/l. Industrial computer and touch panel aid data storage and visualisation, enabling performance prediction via machine learning. Deployed at the dairy company Kozanostra in Osečina, it’s a major water safety advancement.This article/publication is based upon work from COST Action CA21112 -
Offshore freshened groundwater: An unconventional water resource in coastal
regions? (OFF-SOURCE), supported by COST (European Cooperation in
Science and Technology).Publishe
Saturated-threshold event-triggered adaptive global prescribed performance control for nonlinear Markov jumping systems and application to a chemical reactor model
No full textThis paper puts forward an adaptive saturated threshold event-triggered control (STETC) scheme with global
transient and steady-state performance assurance for nonlinear Markov jumping systems. Initially, the dead-
zone model is characterized by an adaptive approximation model while integrating the property of the
Nussbaum function. Then, an improved adaptive global preassigned performance control scheme is developed
under the command-filtered backstepping control framework, where a second-order filter is employed to
tackle the curse of dimensionality faced by the iterative derivation and a novel error compensation signal
is constructed with consideration of the characteristics of dead-zone output and preassigned performance to
eliminate the potential effects caused by filter errors. Drawing inspiration from the preceding ETC results, a
STETC tactic fusing the dynamic parameter is proposed to economize the communication costs, and the control
signal is encoded and decoded as 0 or 1 bits to decrease the bandwidth consumption simultaneously. The
reported STETC method guarantees that overall signals in the closed-loop system keep bounded in probability
while the tracking error rigorously evolves within the prescribed range without dependent on initial values.
Ultimately, two illustrative examples are implemented to check the flexibility and practicality of the reported
control solution.Publishe
THE CONTRIBUTION OF LITERARY TEXTS IN ACHIEVING EMOTIONAL-AFFECTIVE GOALS IN GERMAN LANGUAGE TEACHING
No full textRad je nastao na osnovu jednog dela istraživanja sprovedenog u master radu pod mentorstvom doc. dr Marije Nijemčević Perović, a odbranjen je 5.10.2023. godine.The subject of this paper is to examine the contributions of using literary texts to achieve emotional-affective goals in the process of teaching and learning the German language as a foreign language. The research was conducted among final-year students of the First Kragujevac Grammar School with the aim of examining their previous experiences and attitudes towards reading literature in a foreign language. The data were collected using the group discussion technique. The results show that the use of literature in the teaching of the German language is extremely low, but its implementation in teaching plays a significant role in fostering positive attitudes towards reading in a foreign language and contributes to individual student development, the freer expression of emotions in the classroom, the development of critical thinking, and increased motivation for language learning.Publishe
COW’S MILK IN RELATION TO DIFFERENT PLANT-BASED DRINKS: PHYSICO-CHEMICAL PROPERTIES AND NUTRITIONAL IMPORTANCE
Full text linkIn this study, selected physico-chemical properties of cow's milk were compared with plant-based drinks made from rice, buckwheat, quinoa, almonds, and hazelnuts. Analysis such as conductivity, pH value, viscosity, and density were measured using standardized techniques. Further analysis such as protein, fat, SNF (non-fat solids), lactose, and minerals were determined using a milk analyzer. The results showed that all plant-based drinks had lower values for protein, SNF, lactose, minerals, pH, and conductivity compared to cow's milk. The other parameters showed a different trend, which is described below.Accepted for publishin
ADP-Based Prescribed-Time Control for Nonlinear Time-Varying Delay Systems With Uncertain Parameters
No full textIn this paper, we investigate the problem of prescribed-time optimal control using reinforcement learning
technology. Unlike finite/fixed-time control methods that only achieve stability within specified time bounds, we propose a prescribed-time adaptive dynamic programming (ADP) control approach that ensures both optimality and prescribed-time stability. To address the challenge of solving the nonlinear Hamilton-Jacobi-Bellman (HJB) equation in finite horizon, we construct an actor-critic neural network (NN) with a time-varying activation function. The novel weight update laws are derived from the system’s terminal error and the approximate error of the HJB equation. This derivation eliminates the need for knowledge of dynamic conditions while ensuring compliance with terminal constraints. Based on the proposed prescribed time stability criterion, the control scheme is proven to satisfy prescribed time stability while also ensuring optimal system performance index and bounded weights. We apply the designed control scheme in a time-varying delay system and simulation examples validate the efficacy of the strategy.Publishe
FORMATION OF HYDROXYMETHYLFURFURAL DURINGTHE INDUSTRIAL PRODUCTION OF PLUM PEKMEZ
No full textIt was analyzed the industrial plum pekmez production: blanching, mashing, cooking blanched plum pulp with invert sugar solution and caramel, final heat treatment, cooling pekmez and surface treatment. The aim was to determine the critical stages in which hydroxymethylfurfural (HMF) forms. HMF is synthesized by the thermal sugar decomposition or as one product of the Maillard reaction and can be an indicator of the thermal degree of food processing. Also, HMF is a quality parameter of food due to its potentially harmful effect on consumer health. The cooking blanched plum pulp was a critical stage when the HMF content was significant increased.Publishe
Application of the Random Forest Algorithm for Identifying Abnormal Patterns of Knee Joint Movement
No full textGait analysis through advanced technologies such as motion capture sensors and machine learning techniques enables a detailed study of body movement patterns, significantly contributing to a better understanding of health conditions and sports performance. The application of the Random Forest algorithm for identifying abnormal gait patterns, particularly in cases of anterior cruciate ligament injuries and knee osteoarthritis, has enabled precise classification of gait parameters. Using the OptiTrack system for data collection on both healthy individuals and those with injuries or diseases, a high accuracy model has been achieved in classification, expressed through metrics such as accuracy, precision, recall, and F1 Score. This approach provides efficient and objective classification of potential injuries or diseases, significantly enhancing the diagnosis, therapy, and prevention of knee joint injuries and diseases.Author's versio
Physical and Chemical Properties of Convective- and Microwave-Dried Blackberry Fruits Grown Using Organic Procedures
Full text linkThis study aimed to evaluate the effect of convective and microwave drying on the
bioactive-compounds content of blackberry (Rubus fruticosus) fruits, as well as drying parameters
and energy consumption. The fruit was dehydrated in a convective dehydrator at a temperature of
50 ◦C and 70 ◦C and in a microwave oven at power levels of 90 W, 180 W and 240 W. The highest
amount of anthocyanins, polyphenols and antioxidant capacity were obtained in blackberry fruits
that were microwave dried at 90 W and 180 W (46.3–52.5 and 51.8–83.5 mg 100 g−1 dm of total
anthocyanins, 296.3–255.8 and 418.4–502.2 mg 100 g−1 dm of total phenolics, and 1.20–1.51 and
1.45–2.35 mmol TE 100 g−1 dm of antioxidant capacity for 90 W and 180 W models, respectively).
It turned out that microwave dehydration shortened the processing time and lowered the energy
consumption compared to convective drying (a significantly reduced drying time of 92–99% with
microwave dehydration). Blackberry fruits dehydrated at 240 W showed the shortest dehydration time (59–67 min), minimal energy consumption (0.23 kWh) and the most efficient diffusion
(1.48–1.66 × 10−8 m2 s−1).Publishe
DETERMINATION OF HEAVY METALS IN FRESH FISH
Full text linkConsumption of fish has increased in last 50 years. Fish as a food is changing red meat because it has unsaturated fat and it is the best source of omega 3 fatty acids. Beside it is full of minerals, vitamins and it has high biological value of proteins.The content of heavy metals in the muscle tissue of fish is directly related to the pollution of the water they come from The analysis of the content of heavy metals was done by the Institute of Public Health of the Federation of Bosnia and Herzegovina.The content of lead (Pb) in the tested samples of fresh fish ranged from 0.0015 to 0.0381 mg/kg. The measured content of cadmium (Cd) in the examined samples was in the range of 3.3*10-5 to 0.0053 mg/kg. The content of arsenic (As) in the tested samples ranged from 0.0085 to 1.1668 mg/kg. The mercury (Hg) content in the tested samples of fresh fish ranged from 0.0033 to 0.0991 mg/kg, which is within the allowed values prescribed by the Rulebook. It has been statistically proven that there is a significant difference in the measured values of lead, arsenic and cadmium in the samples of sea and freshwater fish. Aim of this work was to establish do the samples of fresh fish contain concentration of heavy metals more than concentrations prescribed in Rule book about allowed amounts of certain contaminants in food. Thereby ten samples of fresh fish were tested, five samples of marine fish and five samples of freshwater fish. Results showed that all samples of fish satisfy allowed concentration of heavy metals according to the Rule book.Publishe
Heterometallic bridged Pt(II)‐Zn(II) complexes: Influence of the substituent in 4′‐position in inert terpy ligand on antigenotoxicity, potential antitumor activity and mechanism of interactions of the complexes with biomolecules
No full textThe synthesis and characterization of novel hetrometallic complexes [{cis-PtCl
(NH3)2(μ-4,40-bipyridyl)ZnCl(terpy-Cl)}](ClO4)2 (C1a), [{trans-PtCl(NH3)2(μ-
4,40-bipyridyl)ZnCl(terpy)}](ClO4)2 (C2a), [{cis-PtCl(NH3)2(μ-pyrazine)ZnCl
(terpy-Cl)}](ClO4)2 (C3a) and [{trans-PtCl(NH3)2(μ-pyrazine)ZnCl(terpy-Cl)}]
(ClO4)2 (C4a) (where terpy-Cl = 40-chloro-2,20:60,200-terpyridine) was done.
Acid–base titrations were performed by UV–Vis spectrophotometric method to
evaluate the pKa values of corresponding aqua complexes. Interactions
between complexes and important biomolecules, guanosine-50-monophosphate
(50-GMP) and glutathione (GSH) were examined by 1H NMR spectroscopy.
The chloride substituent at the 40 position on the middle pyridine ring of terpyridine
ligand significantly affects the coordination of biomolecules, as well
as overall stability of complexes. The complexes were evaluated in vitro for the
antioxidant prevention of DNA damages. All tested novel complexes demonstrated
a significant reduction in DNA damage against oxidative modifications
of DNA caused by the hydroxyl and peroxyl radicals. Also, cytotoxicity evaluation
showed that significant cytotoxicity occurs only after long-term effect of
C1a, C2a and C3a, complexes in HCT-116 cells. Molecular docking studies
predict results in agreement with experimental research.Publishe