OPTIMAL BATTERY STORAGE LOCATION AND CONTROL IN DISTRIBUTION NETWORK

The paper discusses the problem of the energy losses reduction in electrical networks using a battery energy storage system. One of the main research interests is to define the optimal battery location and control, for the given battery characteristics (battery size, maximum charge / discharge power, discharge depth, etc.), network configuration, network load, and daily load diagram. Battery management involves determining the state of the battery over one period (whether charging or discharging) and with what power it operates. Optimization techniques were used, which were applied to the model described in the paper. The model consists of a fitness function and a constraint. The fitness function is the dependence of the power losses in the network on the current battery power, and it is suggested that the function be fit by a n - order power function. The constraints apply to the very characteristics of the battery for storing electricity. At any time interval, the maximum power that the battery can receive or inject must be met. At any time, the stored energy in the battery must not exceed certain limits. The power of losses in the network is represented as the power of injection into the nodes of the network. The optimization problem was successfully solved by applying a genetic algorithm (GA), when determining optimal battery management. Finally, the optimal battery management algorithm is implemented on the test network. The results of the simulations are presented and discussed

STABILITY, FINITE-TIME STABILITY AND PASSIVITY CRITERIA FOR DISCRETE-TIME DELAYED NEURAL NETWORKS

In this paper, we present the problem of stability, finite-time stability and passivity for discrete-time neural networks (DNNs) with variable delays. For the purposes of stability analysis, an augmented Lyapunov-Krasovskii functional (LKF) with single and double summation terms and several augmented vectors is proposed by decomposing the time-delay interval into two non-equidistant subintervals. Then, by using the Wirtinger-based inequality, reciprocally and extended reciprocally convex combination lemmas, tight estimations for sum terms in the forward difference of LKF are given. In order to relax the existing results, several zero equalities are introduced and stability criteria are proposed in terms of linear matrix inequalities (LMIs). The main objective for the finite-time stability and passivity analysis is how to effectively evaluate the finite-time passivity conditions for DNNs. To achieve this, some weighted summation inequalities are proposed for application to a finite-sum term appearing in the forward difference of LKF, which helps to ensure that the considered delayed DNN is passive. The derived passivity criteria are presented in terms of linear matrix inequalities. Some numerical examples are presented to illustrate the proposed methodology

Experimental and statistical survey on local thermal comfort impact on working productivity loss in university classrooms

The paper presents an experimental analysis of the relationship between local thermal comfort and productivity loss in classrooms. The experimental investigation was performed in a real university classroom during the winter semester in city of Belgrade. Measurements were taken for four scenarios, with different indoor comfort conditions. Variations were made by setting the central heating system on/off, adding an additional heat source to provoke higher indoor temperatures, and measuring the radiant asymmetry impact. Innovative questionnaires were developed especially for the research, in order to investigate students' subjective feelings about local thermal comfort and indoor environmental quality Local predicted mean vote and predicted percentage dissatisfied indices were calculated using data measured in situ. The results were compared to existing models recommended in literature and European and ASHRAE standards. Student productivity was evaluated using novel tests, designed to fit the purposes of the research. Surveys were conducted for 19 days under different thermal conditions, during lectures in a real classroom, using a sample of 240 productivity test results in total. Using the measured data, new correlations between the predicted mean vote, CO2, personal factor and productivity loss were developed. The research findings imply that local thermal comfort is an important factor that can impact productivity, but the impact of the personal factor is of tremendous importance, together with CO2 concentration in the classroom

Software for Measuring Acoustic Parameters in Open-plan Offices

This paper presents a development of software for the measurement and estimation of the quality of acoustic design in open-plan offices. The measurement method is defined by a standard and measurements should be performed in a large number of different spatial positions in order to measure and determine the acoustic quality of the surroundings of as many workstations as possible. The presented software significantly simplifies the process of analyzing open-plan offices by processing the signal at the time of measurement. Furthermore, it allows for the storing of measured signals and parameter values, which can be of importance for further analysis or repeated calculations. The presented procedure leads to the reduction of the necessary hardware elements for completing the analysis. All that is needed for measurement are a sound source, a microphone, a sound card and a computer. As a result, the user obtains a detailed report of the characteristics of the analyzed office space and a descriptive mark which depends on the values of the calculated parameters

Noise Spectrum as a Source of Information in Gas Sensors Based on Liquid-Phase Exfoliated Graphene

Surfaces of adsorption-based gas sensors are often heterogeneous, with adsorption sites that differ in their affinities for gas particle binding. Knowing adsorption/desorption energies, surface densities and the relative abundance of sites of different types is important, because these parameters impact sensor sensitivity and selectivity, and are relevant for revealing the response-generating mechanisms. We show that the analysis of the noise of adsorption-based sensors can be used to study gas adsorption on heterogeneous sensing surfaces, which is applicable to industrially important liquid-phase exfoliated (LPE) graphene. Our results for CO2 adsorption on an LPE graphene surface, with different types of adsorption sites on graphene flake edges and basal planes, show that the noise spectrum data can be used to characterize such surfaces in terms of parameters that determine the sensing properties of the adsorbing material. Notably, the spectrum characteristic frequencies are an unambiguous indicator of the relative abundance of different types of adsorption sites on the sensing surface and their surface densities. We also demonstrate that spectrum features indicate the fraction of the binding sites that are already occupied by another gas species. The presented study can be applied to the design and production of graphene and other sensing surfaces with an optimal sensing performance

Antifungalna aktivnost hitosana prema Alternaria alternata i Colletotrichum gloeosporoides

Chitosan and its derivatives have been reported as a promising alternative for control of postharvest fungal pathogens. The objective of this study was to evaluate in vitro and in situ antifungal activity of chitosan against Alternaria alternata and Colletotrichum gloeosporioides isolated from decayed apple fruits. The fungi were tested in vitro using PDA medium with three concentrations of chitosan (1, 2 and 3 mg/ml). Fungal growth of the test pathogens was significantly affected by all chitosan doses (P lt 0.05) after 7 days of incubation at 25°C. Water solution of 3 mg/ml of chitosan inhibited completely the conidial germination of A. alternata and C. gloeosporioides after 18 h incubation at 25°C. The results obtained from biocontrol assay indicate that the inhibition of postharvest decay of A. alternata and C. gloeosporioides was significantly influenced by chitosan concentrations. Disease incidence in chitosan-treated fruit after 7 days incubation at 25°C was significantly lower than in the positive control for both fungi tested (P lt 0.05). A. alternata and C. gloeosporioides used in this study were progressively inhibited in vitro and in situ with increasing concentrations of chitosan from 1 to 3 mg/ml.Istraživanja pokazuju da su hitosan i njegovi derivati dobra alternativa u kontroli skladišnih fitopatogenih gljiva. Cilj ovog rada bio je da ispita antifungalnu aktivnost hitosana prema Alternaria alternata i Colletotrichum gloeosporoides, izolovanih sa inficiranih plodova jabuke, u in vitro i in situ uslovima. Rast gljiva je testiran in vitro koristeći PDA podlogu sa različitim koncentracijama hitosana (1, 2 i 3 mg/ml). Porast oba patogena je bio značajno smanjen (P lt 0.05) u svim koncentracijama hitosana nakon 7 dana inkubacije na 25°C. Vodeni rastvor hitosana koncentracije 3 mg/ml je u potpunosti inhibirao klijanje konidija A. alternata i C. gloeosporoides nakon inkubacije od 18 sati na temperaturi od 25°C. Rezultati ogleda in situ ukazuju da inhibicija propadanja plodova inficiranih sa A. alternata i C. gloeosporoides zavisi od koncentracije rastvora hitosana. Pojava bolesti na plodovima jabuka tretiranih rastvorom hitosana nakon 7 dana inkubacije na 25°C bila je značajno smanjena za obe vrste gljiva (P lt 0.05) u odnosu na pozitivnu kontrolu. Rast A. alternata i C. gloeosporoides je bio progresivno inhibiran in vitro i in situ sa povećanjem koncentracije rastvora hitosana, od 1 do 3 mg/ml

Selenium nanoparticles as a potential candidate in cancer treatment

The broad spectrum of selenium applications in pharmacy and medicine has been known for a while and strongly depends on its chemical form, size and shape. However, the use of Se often requires consumption over the long period, so the toxicity of Se is always a crucial concern. Majority of available pharmaceutical products contain organic forms of selenium or its salts, but recently, when it comes to cancer treatment, elemental selenium nanoparticles (SeNPs) have emerged as a novel selenium source with the advantage of reduced risk of selenium toxicity, but with same bioavailability and efficacy in increasing the activities of selenoenzimes. In this work we are presenting the fast, reproducible method for producing stable colloidal suspension of amorphous SeNPs (<80 nm). These SeNPS were successful incorporated within PCL microspheres by combining the high speed homogenization and the precipitation in a solvent/non-solvent system. The obtained PCL/SeNPs were characterized by Fourier transform infrared spectroscopy (FTIR), electron microscopy (SEM and TEM), X-ray diffraction (XRD) and thermal analysis methods (TGA-DTA). The cytotoxicity and the formation of intracellular reactive oxygen species of SeNPs as well as of PCL/SeNPs were investigated employing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and using a fluorescent probe (DCFDA test) respectively. Both systems have shown good biocompatibility. The anticancer activity of SeNPs was examined on the HeLa cell line and it was demonstrated that SeNPs exhibits strong, a dose dependent, anticancer activity by preventing further HeLa cells growth and division. Bearing in mind that PCL is well known biodegradable polymer with low degradation rate, it is our opinion that PCL/SeNPs possess a great potential for cancer treatment

Implementation architecture of a home robot assistant

This paper deals with development of a personal robot functioning as a part of a smart home. The overall system is based on the cloud computing model to leverage processing, data sensing and communication power of the robot. At the semantic level, it provides capabilities for improved perceiving and expressing the emotions based on analysis of collected and exchanged history data on emotional states and actions

EFFICIENCY OF BALL MANIPULATION IN BASKETBALL PLAYERS

Abstract. Basketball belongs to the type of sports where the skill of using one’s arms is of the greatest significance for game success. Basketball technique elements which involve the use of the ball are realized solely with the use of the arms, and this is where the name “ball manipulation” stems from. Modern basketball requires top basketball players to display the greatest level of the mentioned ability, irrespective of the playing positions within the team. The aim of this research has been to determine the situational-motor skill of a basketball player’s ball manipulation efficiency with regard to the basketball competition rank. A sample of 30 participants was analyzed, and split into two subsamples (the first subsample consisted of basketball players from the Super League, i.e. the players from the Konstantin basketball team from Nis – 15 participants, and other basketball players from the First Regional League for Men, the Junior Youth Basketball Club from Nis – 15 participants). The ball manipulation efficiency was estimated through the following tests: ball stopping, starting dribbling, ball dribbling around the body, ball dribbling through the legs and leading the ball with variants. In order to determine the inter-group differences, the Multivariate Analysis of Variance (MANOVA) was applied, while the differences between the groups were determined with the Analysis of Variance (ANOVA) for every measuring instrument separately. It was determined that the basketball players of the Super League display significantly greater values in almost all the variables, except one – ball stopping.Keywords: basketball players, ball manipulation, competition rank, differences.es