CONTEMPORARY MATERIALS

MODELING AN INDUSTRIAL ROBOTIC MANIPULATOR IN THE ELECTROMECHANICAL DOMAIN

Carmine Maria Pappalardo, Domenico Guida — Sat, 30 Dec 2023 00:00:00 +0100

In this work, a prototype of a robotic manipulator is developed and its dynamic analysis is per- formed. The system under study was analyzed in a multi-domain environment using two MATLAB tool- boxes, that is, Simscape Multibody and Simscape Electrical. By doing so, an accurate electromechanical model was constructed in this paper. Subsequently, a nonlinear controller was designed for the trajectory tracking of the end effector of the robotic manipulator. The control architecture employed in this work is a Proportional-Derivative (PD) control scheme, which is widely used in industrial applications. The nu- merical results presented in the paper demonstrate the effectiveness of the methodology followed in this investigation.

ADVANCING ENVIRONMENTAL SUSTAINABILITY: ENHANCED PHO- TOCATALYTIC DEGRADATION OF CEFOPERAZONE USING ZnO AND H2O2 UNDER DIFFERENT RADIATION SOURCES

Sat, 30 Dec 2023 00:00:00 +0100

Cefoperazone is a widely utilized antibiotic from the cephalosporins group to treat bacterial infections. Nevertheless, due to its extensive use as a β-lactam antibiotic, it has been found to accumulate in aquatic environments, leading to notable adverse effects on flora and fauna. Consequently, there arises a necessity for its removal from the environment. The aim of this work was to investigate the efficiency of photocatalytic degradation of cefoperazone by ZnO and H2O2 using different types of radiation (simulated solar (SS), UV-LED, and UV). The applied nanomaterial in the presence of H2O2 showed significant effi- ciency in removing cefoperazone compared to direct photolysis. In the first 20 min of irradiation, 49.0% and 59.4% of cefoperazone were degraded when SS and UV-LED were used, respectively, while cefopera- zone was completely degraded under UV irradiation. The reaction rate constant indicates that the degrada- tion of cefoperazone is pseudo-first order..

OVERVIEW OF PHYSICS-INFORMED NEURAL NETWORKS APPLICATIONS

Bogdan Milićević, Miloš Ivanović, Boban Stojanović, Nenad Filipović — Sat, 30 Dec 2023 00:00:00 +0100

When simulating various physical phenomena, the law of the phenomenon is often known in advance, in the form of a partial differential equation, that needs to be solved. Numerical methods, such as the finite element method, have been developed over decades, and these methods approximate the solution to the partial differential equation. However, these methods can be computationally demanding. On the oth- er hand, neural networks, can provide predictions that approximate the given partial differential equation. Neural networks are computationally more efficient than numerical methods, but they often face issues of generalization and consequently problems with solution accuracy. Insufficient generalization, among other things, can result from data collected from numerical simulations. In the last few years, physics-informed neural networks are being developed, for which it’s not necessary to gather data from simulations. These networks use automatic differentiation and during training, they minimize the residuals of the partial differ- ential equation, its initial, and boundary conditions. After training, these neural networks can be used as a replacement for traditional numerical solvers.

TRANSPORT CHARACTERISTICS OF ELECTRONS IN NITROUS OXIDE (N2O) UNDER THE INFLUENCE OF CROSSED ELECTRIC AND MAGNETIC DC FIELDS

Snježana Dupljanin, Olivera Šašić, Zoran Lj. Petrović, Dragoljub Mirjanić — Sat, 30 Dec 2023 00:00:00 +0100

Monte Carlo (MC) calculations of transport and rate coefficients of an electron swarm moving in nitrous oxide (N2O) under the influence of DC crossed electric and magnetic orthogonal fields are present- ed. The set of cross sections for e-/N2O scattering obtained in our previous investigations was used as the initial parameter. Calculations of mean energy, drift velocity, diffusion coefficients and rate coefficients for elastic and individual inelastic processes were performed for five different values of the reduced magnetic field (B/N = 100 Hx, 200 Hx, 500 Hx, 1000 Hx and 2000 Hx, 1Hx = 10-27 Tm3), where for each of these values, the value of the reduced electric field (E/N) ranged from 50 Td to 2000 Td (1Td = 10-21Vm2). The ratio of cyclotron to total collision frequency in these cases is less than one for all values of B/N (except for the highest one when it is slightly greater than one), so we may claim that our swarm is in a collision-domi- nated regime. The cooling effect of the swarm is observable, i.e. there is a decrease in its mean energy as the magnetic field increases, as well as a decrease in the drift velocity component in the electric field direction. Electron diffusion is slightly anisotropic for the higher values of B/N.

APPLICATION OF THE METHOD OF FOCCULATION AND SELECTIVE FLOCCULATION METHODS IN THE TREATMENT OF INDUSTRIAL SLUDGE FROM THE IRON ORE CONCENTRATION PROCESS

Ljiljana Tankosić, Svjetlana Sredić — Sat, 30 Dec 2023 00:00:00 +0100

The paper presents research on the use of flocculation and selective flocculation methods in the treatment of industrial sludge, generated in the processing of iron ore minerals. The large quantity of fine sized sludge disposed as final waste still contains a relatively high concentration of iron minerals, as well as quartz and clay minerals, as tailings. It is both an environmental and an economic problem. In both cases it is useful to use flocculants to accelerate settling of fine particles. The action of flocculants, which accelerate settling, can be selective or non-selective. The research was aimed at determining the conditions under which selectivity can be achieved when using some commercial flocculants.

THE INFLUENCE OF THE CATALYST ON THE RATE CONSTANT OF THE CHEMICAL REACTION OF ESTERIFICATION OF OLEIC ACID WITH METHANOL

Darja Pečar, Vladan Mićić, Andreja Goršek — Sat, 30 Dec 2023 00:00:00 +0100

Catalysis and catalysts play an important role in modern technology. Catalysis means a change in the rate of a chemical reaction under the influence of a substance that does not change chemically as a result of the reaction. This substance is called a catalyst. The catalyzed reaction proceeds on a different reaction path than the uncatalyzed reaction, thanks to the participation of the catalyst. The reactants are absorbed on the surface of the catalyst, and then a mutual reaction of the adsorbed species occurs. The reaction produc- es a product that is desorbed from the surface, while the catalyst remains unchanged and ready for a new reaction cycle. An important piece of information for evaluating the quality of a catalyst is the rate of the reaction in which it participates. The subject of kinetic research is the study of the influence of process pa- rameters on the reaction rate. It is safe to say that the study of reaction kinetics is a central part of chemical reaction engineering. Therefore, the study of the kinetics of real heterogeneous catalysts is of particular im- portance, both for the improvement of existing catalysts and for the development of new ones. These tests involve determining the influence of process parameters such as the type of catalyst present, temperature, pressure, and concentration of reactants and products on the reaction rate. In this work, the influence of the mass of the catalyst at a certain temperature on the rate constant of the chemical reaction of esterification of oleic acid with methanol was studied. The catalyst used was mesoporous silica, an amorphous solid that can be obtained by drying hydrogels. It was found that as the mass of the catalyst increases, the rate of the chemical reaction constant also increases, i.e. the rate of the esterification reaction increases.

INTEGRATION OF NANOTECHNOLOGY AND HERBAL MEDICINE: THERAPEUTIC POTENTIAL FOR IMPROVEMENT OF HEALTH CARE

Anđela Bojanić, Relja Suručić, Mirjana Đermanović — Sat, 30 Dec 2023 00:00:00 +0100

Herbal medicine represents one of the oldest forms of medical practice since ancient times, which is still used around the world and includes the use of herbal medicines for preventive or therapeutic purposes. On the other hand, nanomedicine represents a new scientific field that uses nanotechnology, the manipulation of materials on the nanoscale (1 - 100 nm), for the diagnosis, treatment and prevention of diseases at the molecular level. Although these two disciplines are very different at first glance, their integration could unlock the full therapeutic potential of phytotherapy by enabling innovative approaches to improve the bioavailability and efficacy of herbal medicines through targeted and controlled delivery, allowing to overcome its current limitations and reduce side effects. This paper explores the importance of implementing nanotechnology in herbal medicine, emphasizing its potential impact on health care. Also, the techniques of encapsulating herbal medicines into nanomedicines, various herbal nanoformulations and application and modes of action, are presented. In conclusion, continued research in this area .Is considered a key factor in unlocking the full potential of nanomedicine application in herbal medicine. Such research drives innovation, as well as personalized approaches to therapy and advances healthcare, which could pave the way for a healthier and more sustainable future.

BIOMEDICAL ENGINEERING AND ADDITIVE MANUFACTURING

Zorana Golubović, Ljubiša Petrov, Božica Bojović — Sat, 30 Dec 2023 00:00:00 +0100

Additive manufacturing (AM) technologies have evolved significantly in recent decades, bring- ing new trends to production processes. The advantages compared to conventional technologies are numer- ous: production is simpler and faster, geometry can be adjusted more easily, the quality of finished parts is better, less material is wasted, and costs are lower. Because of the wide range of possibilities, the different AM processes and the materials that can be used, these technologies have found their place in many indus- tries, not least in biomedical applications. Flexibility in geometric freedom, in particular, is important for the fabrication of biomedical devices. It is already known that AM technologies can improve and facilitate diagnostics through the fabrication of customized and in-demand parts, support consultation between phy- sicians and patients, and thus provide the opportunity to develop individualized, patient-specific medicine. This review briefly outlines current applications and AM techniques present in the biomedical field.

NEWTON’S SECOND LAW IN THE SERVICE OF CLIMATE CHANGE – TEMPERATURE TREND ANALYSIS

Dragana Malivuk Gak, Zoran Rajilić — Sat, 30 Dec 2023 00:00:00 +0100

New approach of using Newton’s Second Low in the analysis of a non-mechanical system is pre- sented. A force that satisfies Newton’s second law is introduced, where real time series of average monthly temperatures are transformed into time-dependent force parameters. The force acts on a point in data space. This method of data analysis can be considered as a type of information filtering. Extreme values of certain force parameters were analyzed as potential predictors of temperature trend emergence. Specific force pa- rameters were calculated based on the average monthly temperatures values for several cities in Bosnia and Herzegovina. A review and discussion of possible changes in average monthly temperatures in the future are provided, based on the values of the obtained force parameters.

TREATMENT OF SEVERE CROWDING WITH SELF-LIGATING FIXED ORTHODONTIC APPLIANCE

Sat, 30 Dec 2023 00:00:00 +0100

Introduction: Crowding in orthodontics presents a discrepancy between tooth size and dental arch length. Crowding of teeth is more often diagnosed in mandibular dental arch. Crowding was classified as moderate (-5.1 mm or more of discrepancy), mild (-0.1 and -5 mm) of discrepancy, and no crowding (zero or a positive discrepancy) by W. Proffit. Over the last few years, the use of self-ligating brackets in orthodontics has progressed considerably. According to some authors, selfigating appliances are more ef- fective in treating moderate crowding.

Aim: To present the treatment of cevere crowing of both dental arches without premolar extractions, using self-ligating fixed orthodontic appliance.
Material and method: Male patient 12 years old was diagnosed with severe crowding in both upper and lower dental arches. Study cast analysis showed severe crowding of 8 mm in the upper and 9 mm in the lower dental arch with dental class I. Lateral cephalometric analysis showed slight mandibular retrogna- thism (SNB 78°) with skeletal class I (ANB 4°). There were no significant vertical skeletal deviations (SpP/ MP 20°, Bjork’s sum 389°, Jarabak 67,7%). Both upper and lower central incisors were retroinclined (I/SpP 102°, IMPA 95°). There were no deviations in maxillar corpus and mandibular corpus and ramus length. Treatment with self-ligating fixed orthodontic appliance was indicated. The active phase of the treatment lasted 26 months. During the treatment, interproximal reduction (IPR) was performed on upper and lower front teeth.

Results and conclussion: Stable class I occlusion was acheieved. Both upper and lower dental arches were slightly expanded. Severe crowding was treated successfully Treatment result was stable, with no signs of relapse, with the overjet of 2 mm and overbite of 3 mm. Severe crowding in young patients can be succsess- fully treated without extractions with self-ligating fixed orthodontic appliance in cases of horizontal growth pattern ,with retroinclined upper and lower incisors.

APPLICATION OF HIGH PERFORMANCE POLYMERS IN PROSTHETIC RESTORATION ON IMPLANTS

Sat, 30 Dec 2023 00:00:00 +0100

For prosthetic hybrid restorations on implants, different combinations of materials are used, from metal alloys, titanium, ceramics, polymers or composites. The aim of this paper is to summarize the char- acteristics and advantages of certain polymers in the production of hybrid restorations, as well as to present the protocol for treating patients with this type of restoration. Polymers based on poly-ether-ether-ketone have gained great popularity and success in the field of implant-prosthetic therapy. Among them, the most famous high-performance polymers developed by Bredent (Bredent group, Senden Germany) are BioHPP (containing 20% ceramic fillers) and breCAM.HIPC (highly cross-linked polymer composite material). Both polymers are machinable and are used to make temporary and permanent resaturations in prosthetics. They are biocompatible and non-allergenic, do not contain metal, oxide and monomer components, and also do not discolor the gingiva. They are characterized by excellent workability and elasticity, which is greater than zirconium ceramics and metal alloys, different shades of color is characteristics for breCAM. HIPC, unlike BioHPP, which is monolithic and monochromatic. Due to their characteristics, these high-per- formance polymers can be exceptional “allies” for the restorations on implants.

COMBINED ORTHODONTIC AND SURGICAL TREATMEN IN PATIENT WITH MANDIBULAR PROGNATHISM

Sat, 30 Dec 2023 00:00:00 +0100

The aim of this case was to present a combined orthodontic-surgical treatment for a 30-year-old patient. The initial clinical examination revealed a Class III malocclusion, concave profile, 4.5mm overjet, and 2mm overbite. The treatment plan included orthodontic preparation with fixed appliances, surgical correction of skeletal discrepancies, and post-surgical orthodontic treatment. Lateral cephalograms were taken before the orthodontic therapy, just before the surgical intervention, and after the treatment, following the removal of fixed appliances. On the initial lateral cephalogram SNB angle was 88°, ANB -5°, SpP/MP 28°, total Bjork’s polygon angle 405°, I/SpP 71°, i/MP 111° and mandibular corpus length was increased by +11mm. On the final post-surgical lateral cephalogram, after the intervention and appliance removal the SNB angle was 81°, ANB 3°, SpP/MP 25°, total Bjork’s polygon angle 398°, I/SpP 64°, i/MP 96° and man- dibular corpus length was increased by +3mm. The pre-surgical orthodontic treatment lasted 12 months, followed by bimaxillary surgery. The post-surgical orthodontic treatment lasted 12 months. After appliance removal, a retentive phase with night-time wear of retainers was implemented. The result was stable Class I occlusion, satisfactory profile appearance, 2.5mm overbite, and 2mm overjet.