Variability of the chloroplast dna of sessile oak (Quercus petraea agg. Ehrendorfer, 1967) in Serbia

Genetic variability of sessile oak (Quercus petraea agg. Ehrendorfer, 1967) in Serbia is estimated applying cpDNA universal primer pairs that were characterized by a high informative level for chloroplast genome variability assessment in previous investigations. Five different haplotypes were detected in the analyzed sample material from populations in Serbia

A Hybrid PPSOGSA Algorithm for Optimal Volt/VAr/THDv Control in Distorted Radial Distribution Systems

This paper presents a new hybrid PPSOGSA algorithm based on the phasor particle swarm optimization (PPSO) and gravitational search algorithm (GSA) for solving the Volt/VAr/THDv control optimization problem in radial distribution systems with non-linear loads. The PPSOGSA’s performance is analyzed and evaluated using the standard IEEE 30-bus radial distribution test system. The optimal solutions are obtained based on the following three optimization criteria: minimization of total active power losses, minimization of the voltage deviation, and a simultaneous minimization of total active power losses and voltage deviation. The voltage total harmonic distortion levels (THDv) are estimated using the decoupled harmonic power flow (DHPF) algorithm. Simulation results, obtained using the proposed PPSOGSA-based approach, are compared with those obtained using the other optimization algorithms such as PSO, PPSO, GSA, and PSOGSA. It is shown that the PPSOGSA-based approach has better performance in comparison to the other optimization techniques

Optimal location and sizing of capacitor banks in distribution networks to reduce harmonic distortion and improve voltage profile using genetic algorithm

This paper considers the problem of determination of optimum locations and sizes of capacitor banks (CB) for reactive power compensation in distribution systems to reduce harmonic distortion and improve voltage profile. Genetic Algorithm (GA) was used for solving this non-linear multi-objective optimization problem with constraints. A detailed methodology was presented for solving the power flow problem at fundamental and higher harmonic frequencies of interest and models of network components in harmonic analysis. The proposed procedure was successfully tested on the standard IEEE 33-bus test system for three different objective functions. Calculations showed the efficiency of GA for solving this complex problem

Risk of thermal pollution of the Danube passing through Serbia due to thermal power plants

A thermal power plant (TPP) uses large amounts of fresh water, mostly for cooling purposes. Among different types of cooling systems, once-through cooling is the most water-intensive and has the greatest environmental impacts. From the view-point of the steam cycle efficiency, this type of cooling still provides the most efficient electricity production, and therefore is widely used. Water is withdrawn from nearby water bodies, absorbs heat from the steam in a condenser, and then discharged back to its original source at higher temperatures causing severe environmental impacts, including fish killing, disturbing ecosystems, and heating-up natural water bodies. The total installed capacity of almost 1100 MW on the right bank of the Danube in Serbia threatens the ecosystem of this large international river due to thermal pollution. This problem will be even more pronounced in the near future, due to an inevitable increase in production capacity for new 350 MW, currently under construction. Herein, analysis of the legal framework for the protection of water from thermal pollution as well as analysis of the actual situation on the site of the TPP “Kostolac” in Serbia are presented. Based on meteorological and hydrological parameters, configuration and operation parameters of the plant, the numerical simulation of the condenser was carried on. The temperature of the water leaving condenser and amount of heat discharged back to the river are obtained. According to those results, the analysis of the existing thermal pollution of the Danube River in the flow through Serbia is given by numerical simulation using software ANSYS CFX. Analysis of thermal discharge into the Danube for the five-year period has been carried out. The cooling water effluent causes a temperature increase in the area of the right bank of the Danube, and this thermal disturbance extends along the right river bank for kilometers. Note that the flow rate of the Danube is currently large enough to compensate this thermal disturbance, but for a smaller river and/or larger electricity production capacities, this influence would have even more significant consequences on the ecosystem, making those results even more useful for further analysis

Reslizumab versus placebo for poorly controlled, severe eosinophilic asthma: Meta-analysis

Background/Aim. Reslizumab is humanized monoclonal antibody produced by recombinant DNA technology which binds to circulating interleukin-5 (IL-5) and down-regulates the IL-5 signaling pathway. Reslizumab is indicated for the add-on maintenance treatment of patients 18 years and older with severe eosinophilic asthma phenotype whose symptoms were inadequately controlled with inhaled corticosteroids. The aim of this meta-analysis was to assess the efficacy and safety of reslizumab compared to placebo in patients suffering from inadequately controlled, moderateto- severe asthma with elevated blood eosinophil counts. Methods. Our meta-analysis was based on systematic search of literature and selection of high-quality evidence according to pre-set inclusion and exclusion criteria. The effects of reslizumab and placebo were summarized using Review Manager (RevMan) 5.3.5 and heterogeneity was assessed by the Cochrane Q test and I² values. Several types of bias were assessed and publication bias shown by Funnel plot and Egger’s regression. Results. The meta-analysis included 5 randomized, placebo-controlled clinical trials. Reslizumab 3.0 mg/kg produced substantial improvements in forced expiratory volume in 1. second (FEV 1) (mean difference 0.15 [0.10, 0.21]) and in forced vital capacity (FVC) (mean difference 0.21 [0.09, 0.32]) over the 15 or 16-week treatment period, substantial decrease versus placebo in Asthma Control Questionnaire (ACQ) score (mean difference -0.28 [-0.41, -0.16]), and substantial increase vs. placebo from baseline in Asthma Quality of Life Questionnaire (AQLQ) total score (mean difference 0.24 [0.06, 0.43]). Also, reslizumab 3.0 mg/kg caused less adverse events versus placebo (OR 0.67 [0.51, 0.88]), especially asthma worsening (OR 0.53 [0.36, 0.77]) or bronchitis (OR 0.42 [0.24, 0.74]). Conclusion. On the basis of published clinical trials reslizumab could be considered as an effective and safe therapeutic option for severe, poorly controlled eosinophilic asthma for the time being. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 175007

Controlling the thermal environment of underground power cables adjacent to heating pipeline using the pavement surface radiation properties

This paper shows how the pavement surface radiation properties can be used to control the thermal environment of 110 kV underground cables in order to increase their ampacity. It is assumed that the ampacity is additionally affected by the cable bedding size and an underground heating pipeline. Thanks to an experimental apparatus, some useful data were collected for the validation of two different finite element method based models that predict the effect of the pavement surface radiation properties on the cable ampacity. The first model corresponds to the experimental apparatus and actual indoor conditions, while the second one corresponds to the theoretical case and assumed outdoor conditions (taking into account the thermal effects of solar radiation, cable bedding size, and heating pipeline). This paper examines two possible cases of outdoor conditions, one corresponding to summer period (the most unfavorable ambient conditions) and another one corresponding to winter period (the most common winter conditions in Serbia). This proposed new method is based on the experimental data and generalized using the finite element method in COMSOL. It is found that the ampacity of the considered 110 kV cable line can be increased up to 25.4 % for the most unfavorable ambient conditions and up to 8 % for the most common winter conditions. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR33046