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The integration of electromobility with its required charging infrastructures into the existing power grid, which is demanded by politics and society, is an enormous challenge for electrical power grid operators. Especially considering further challenges, such as the electrification of heat supply systems and sector coupling, it is to be expected that the power grid’s capacity will be strongly overstrained. On the other hand, grid expansion is an extremely expensive and time-consuming method of ensuring that the existing grid is not overloaded, and sufficient grid capacity is available. A suitable grid operations management approach can enable comprehensive and grid-serving control of flexibility, especially charging processes. This article presents a cluster-based and incentive-oriented grid operation management concept and describes the integration of the system into the current German regulatory framework. In addition, the structural integration of charging infrastructures for electromobility into a grid-oriented control system is presented. The suitability of grid charges and their dynamization for stimulating grid-oriented behavior is analyzed. Furthermore, the derivation of additional costs arising from the utilization-dependent thermal aging of grid assets and their imputed integration into the incentive system is described.

The decentralized feed-ins from distributed energy resources (DER) represent a significant change in the manner in which the power grid is used. If this leads to high loads on electrical equipment, its aging can be accelerated. This applies in particular with regard to the thermal aging of older generations of power cables, namely paper insulated lead covered (PILC) cables. This type of power cable can still be found frequently in medium voltage (MV) networks. If aging of these cables is significantly accelerated in the presence of DER, distribution system operators (DSO) could face unplanned premature cable failures and a high replacement demand and costs. Therefore, this paper investigates the thermal aging of PILC cables in a MV distribution network benchmark for different load scenarios, using standardized load profiles and representative expansion scenarios for wind power and photovoltaics plants in particularly affected network areas in Germany. A main objective of this paper is to present a methodology for estimating the thermal degradation of PILC cables. An approach is used to draw simplified conclusions from the loading of cables to their conductor or insulation temperature. For this purpose, mainly Joule losses are considered. In addition, thermal time constants are used for the heating and cooling processes. Based on the insulation temperature, thermal aging is determined using the Arrhenius law or the Montsinger rule. However, it is important to note that there is an urgent need for research on reference data in this area. For this reason, the results of the lifetime estimation presented in this paper should only be considered as an approximation if the selected reference data from the literature for the aging model are actually applicable. The lifetime assessment is performed for a highly utilized line segment of the network benchmark. Accordingly, extreme values are examined. Different operational control strategies of DSO to limit cable utilization are investigated. The results show that the expansion of DER can lead to a short but high cable utilization, although the average utilization does not increase or increases only slightly. This can lead to significantly lower cable lifetimes. The possible influence of these temporarily high loads is shown by comparing the resulting cable lifetime with previous situations without DER. It is also shown that DSO could already reduce excessive aging of PILC cables by preventing overloads in a few hours of a year. In addition to these specific results, general findings on the network load due to the influence of DER are obtained, which are of interest for congestion management.

The applicability of lanthanide doped alkaline metal sulphates as a new type of dosimeters for EPR dosimetery of ionizing radiation has been investigated in an attempt to obtain a dosimeter with better characteristics than the commonly used alanine dosimeter. Irradiation of samples doped with different lanthanides (Y, Ln, Gd) showed that the best sensitivity is obtained using dosimeters doped with Y2(SO4)3. Different procedures for manufacturing dosimeters were studied and an optimum procedure was established. The time stability of the EPR signal of the irradiated Y2(SO4)3 dosimeter was investigated using a 15N-PDT standard and no fading of the EPR signal was observed over at least two weeks. The dose dependence of alanine and Y2(SO4)3 doped K3Na(SO4)13 dosimeters irradiated in the range 20 Gy 200 kGy was analysed using a combination of 1-hit and 2-hit mechanisms of free radicals creation.

The 3D printing parameters are known to have a significant impact on manufactured parts, and the layered morphology of these parts makes mechanical design analysis for engineering applications difficult. In this work, the tensile strengths and microhardness of 3D printed polylactic acid (PLA) specimens with different orientations and numbers of individual layers of mesh material (polyvinyl chloride – PVC) were investigated as a laminate composite. Composite specimens were obtained using 3D printing via fused deposition modelling (FDM). Moreover, the influence of printing parameters (i.e. infill density and layer height) and the number and orientation of reinforced meshes on the mechanical response was investigated. Fracture strength of PLA/PVC laminate composites ranges from 31.30 MPa (3 PVC mesh layers; mesh height position: 25 %│50 %│75 %; infill density: 60 %; PVC mesh orientation: 90°│45°│90°; layer height: 0.2 mm) to 18.62 MPa (without PVC mesh; infill density: 30 %; layer height: 0.1 mm) demonstrating a significant impact of the number of the PVC mesh layers, infill density of PLA and layer height on the final mechanical parameters of printing PLA/PVC elements. The surface hardness at the micro load level showed that the number of reinforcement layers affects the microhardness value, as well as material filling and mesh orientation. The specimen with the following parameters gave the best results: layer height: 0.2 mm; 3 PVC mesh layers; infill density: 60 %; PVC mesh orientation: 90°│45°│90°. The average hardness values for one layer and three layers of mesh were in accordance with tensile test results.

Composite materials and structures are widely used and applied in many industries owing to their advantages, such as satisfactory stiffness-to-mass ratio and corrosion resistance. However, during their operating life, responsible parts subject to complex loads may change and their properties might deteriorate. To ensure structural integrity it is necessary to monitor and regularly check the performance of composite structures. This paper investigates the change of frequency characteristics of two rectangular composite (carbon-epoxy) plates after inflicting structural damage. Following the necessary preparation of the structure's upper surfaces by white-and-black stochastic pattern, the responses (free vibratory movement) of structures to momentary excitation were recorded by an optical, contactless 3D digital image correlation (DIC) system that contains a set of ultrafast cameras. In order to determine the natural frequencies of the plates, the recorded time-domain responses were post-processed, i.e. converted to the frequency domain by fast Fourier transform (FFT). The reduction in values of natural frequencies is observed on the damaged structures. The performed experiments demonstrate the applicability of the DIC method in the structural health monitoring of composite parts.

Three-dimensional printed plastic products developed through fused deposition modelling (FDM) take long-term mechanical loading in most industrial prototypes. This article focuses on the impact of the 3D printing parameters, type of thermal treatment and variation of characteristic dimensions of standard specimens on the tensile properties of poly(lactic acid) (PLA) material. Two mediums were used for thermal treatment: NaCl powder and plaster. The specimens immersed in NaCl powder were heated to the melting temperature of the filament (200 °C), while the processing of the plastered specimens was performed at a temperature of 100 °C. After treatment, the specimens were cooled at room temperature (25 °C), and the dimensions of the annealed and untreated specimens were controlled. The tensile test of the specimens was performed on the universal test machine. The response surface methodology (RSM) is employed to predict the tensile stress by undertaking input parameters. The analysis of variance (ANOVA) results revealed that the untreated specimens, orientation –45/45 and layer thickness of 0.1 mm had the highest tensile stress value. Thermal treatment in plaster showed a significant increase in tensile strength, while the best specimens were obtained after treatment in NaCl, and all refer to the –45/45 (0.1 mm) orientation.

The paper analyses the current situation and perspectives of construction waste management in the territory of Jablanica district, Serbia. Considering the importance of construction waste management for the ecosystem, the state and perspectives are assessed through the assessment of the possibilities of reuse and recycling. According to Rulebook on waste categories with catalogue in Serbia, construction waste found at the landfill Donja Jajina is classified and observed in this research. Based on a six-month daily monitoring of the material flow of construction waste at the landfill in Dona Jajina, the current estimated state of the amount of waste as well as further growth of waste at the landfill is presented. Using MATLAB simulation code, predictions for the next 15 years are obtained, and conclusions are made. At the moment, concrete, brick, asphalt, as well as other construction waste are being buried at the landfill in Donja Jajina, and no further waste treatment is being done. The landfill has a lot of material that could be further used and put into use. It is necessary to build a stationary recycling plant on the landfill itself that would produce recycled aggregates and thereby reduce the use of natural aggregates.

Odavno se zna da na komunikacija ispunjava najveći deo vremena rada menadđera tako da ona, saglasno tome, predstavlja neizbežan predmet proučavanja i u nedavno sprovedenim istraživanjima na polju menadžmenta. Postoji opšte očekivanje da jasna i efektivna komunikacija u organizaciji predstavlja ključni resurs za postizanje njenih ciljeva. Ovo je, međutim, lakše reći nego ostvariti u stvarnom organizacionom kontekstu. Glavni cilj ovog rada je da ukaže na značaj komunikacije u savremenom poslovanju. U najvećem delu rada se razmatra uloga menadžera u svetlu njihovih uloga na polju komuniciranja. U radu je pokazano da različite profesionalne veštine, uključujući i komunikativnu kompetentnost, manadžeri mogu da nauče i uvežbaju u nastojanju da efektivno učestvuju u bilo kojoj formi komunikacije unutar organizacije.

Five series of specimens with two different print orientations (−45/45 and 0/90) and two print layer thicknesses (0.1 and 0.2 mm) were made. In total 60 specimens with 100% filament infill were made. One specimen series (20 pieces) was isolated as a reference or thermally untreated. Before the thermal treatment (annealing), two specimen moulding methods were used: NaCl powder (granulation 63 mm: 20 pieces) and Calcium Sulphate (Gypsum: 20 pieces). During the annealing, specimens immersed in NaCl powder were heated in a drying oven to the filament melting point (for PLA: 200°C, with a duration interval of 30 min), while the treatment of the heated specimens in gypsum was performed at a temperature of around 190°C, with duration interval of 3 h with the observed temperature inside the mould of about 100°C. An ultrasonic bath and a drying oven were used in the gypsum treatment. Temperature measurement and control during both annealing treatments were performed using a thermal imaging camera, while the temperature control inside the drying oven was performed using a digital thermometer. After treatment, the specimens in the moulds were cooled at room temperature, and the dimensions of annealing and untreated specimens were controlled. Surface morphology was characterised using scanning electron microscopy (SEM). The SEM analysis reveals improved internal structure after heat treatment of the PLA specimens. These results show that the investigated specimens after heat treatments had better structural properties than the referent specimens. Tensile testing on a universal testing machine in compliance with the ASTM D638 standard was also performed. The referent PLA specimen with −45/45 and layer thickness of 0.1 mm had the highest tensile stress value (64.08 MPa) while the specimen with minimal tensile stress value before fracture was 0/90, 0.2 mm (54.81 MPa). Heat treatment in gypsum showed the most significant increase in strength with −45/45 (0.1 mm) being the strongest (71.66 MPa) while the strongest specimen treated in sodium chloride was −45/45 (0.1 mm) with maximum tensile stress of 70.08 MPa. The mechanical characteristics of the PLA were characterised using the Vickers microhardness tester. The PLA microhardness value was calculated according to standards ASTM E384 and ISO 6507. The referent PLA specimen with −45/45 (0.2 mm) orientation shows the maximal microhardness value (125 MPa), and the minimal microhardness value was observed for the 0/90 (0.1 mm) orientation specimens (108 MPa). The heat treatment specimens in gypsum have a better hardness (185 MPa) than those treated in gypsum (165 MPa), with microhardness increasing by about 12%. The essence of the work is reflected in the additional filament processing to achieve a better structural and mechanical performance of the materials and reduce the anisotropy that is characteristic of 3D printing.

The influence of various intensities of ultrasound applied for the electrolyte stirring on morphological and mechanical characteristics of electrolytically produced copper coatings has been investigated. The copper coatings produced by the galvanostatic regime of the electrodeposition from the basic sulphate electrolyte and the electrolyte with added levelling/brightening additives at the low temperature were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques (surface morphology and topography, respectively) and by Vickers microindentation (hardness). The roughness of coatings increased with the increasing intensity of ultrasound, indicating that morphology of the coatings worsened with the enhanced application of ultrasonic waves. This is attributed to the strong effect of ultrasound on hydrodynamic conditions in the near-electrode layer, which is manifested by the increase of share of the activation control in the mixed activation-diffusion control of electrodeposition with increasing the intensity of ultrasound. The concept of "effective overpotential" originally proposed to explain a change of surface morphology in the conditions of vigorous hydrogen evolution is also applicable for a change of morphology of Cu coatings under the imposed effect of ultrasonic waves. Hardness analysis of the coatings showed that an intensity of applied ultrasound did not have any significant effect on the hardness, especially for the Cu coatings produced from the basic sulphate electrolyte.

This investigation has been carried out in order to analyse and compare the hardness response of different composite systems of the same type, named 'soft film on hard substrate' composite system. Composite systems of mono- and multilayered electrodeposited Ni and Cu thin films on (100) and (111)-oriented monocrystalline Si wafers and 100 µm-thick electrodeposited Ni film as the substrates were fabricated. The indentation behaviour of these composite structures was characterized using Berkovich nanohardness and Vickers microhardness testing. The measured hardness is so-called 'composite hardness', because the substrate participates in the plastic deformation during the indentation process. The contribution of the substrate to the measured hardness starts at indentation depths of the order of 0.07- 0.2 times the film thickness. Dependence of nanohardness and microhardness values on electrodeposition process conditions, substrate and film microstructure, total film thickness, layer thickness and Ni/Cu layer thickness ratio for different composite systems ratio was investigated. Composite hardness model of Chicot-Lesage (C-L) was chosen and applied to experimental data in order to determine absolute film hardness.

This paper presents the results of multi-criteria ranking of the Danube water quality along itscourse through Serbia by using PROMETHEE/GAIA method. The ranking was based on the valuesof the water quality parameters measured at eight measuring stations on the Danube River in 2010.For the purposes of the investigation, ten water quality parameters that indicate physical, chemicaland microbiological characteristics of water were selected. These parameters are also used in theWQI (Water Quality Index) methodology in determining the overall water quality. The results showthat the water quality on the exit profile is better than the quality of the water at the entrance profile.

The transformation of the synthesized allicin, using conventional method, the influence of ultrasound and microwaves, in different organic solvents (acetonitrile, acetone, methanol, and chloroform), at various temperatures (room temperature, 45∘C, and 55∘C) was investigated. Allicin degradation kinetic was monitored by HPLC. Allicin transformation under the effect of microwaves is faster than transformations performed under the influence of ultrasound or by conventional method. Increase of the temperature accelerates allicin transformation. Pharmacologically active compounds of (E)-ajoene, (Z)-ajoene, 3-vinyl-4H-1,2-dithiin, 2-vinyl-4H-1,3-dithiin, and diallyl disulfide were isolated from the mixture of transformation products of allicin under the influence of microwaves in methanol at 55∘C, which is according to kinetic parameters (highest values of the order of reaction and the lowest activation energy) the optimal method.

The Danube is an international river passing partly through Serbia. The protection of the environment and sustainable use of water resources is a primary task that implies constant monitoring of the quality status and evaluation of ecochemical status of the water in the Danube basin. The investigation includes calculation of all-inclusive water quality by the Serbian water quality index (SWQI) method and an evaluation of eco-chemical status of the Danube water in terms of water quality parameters from the entry to the exit point along its course through Serbia in the year of 2009. The results show that the overall quality of the Danube water on the territory of Serbia corresponds to the descriptive indicator of “very good” water. According to the Council Directive 75/440/EEC, the evaluation of the ecostatus, with slight deviation of individual parameters at Pančevo, corresponds to A1 category of the surface water quality intended for the abstraction of drinking water supplies in member states.