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Confectionery industry wastewater contains substantial amounts of organic and inorganic matter, posing a significant environmental burden. Microbial bioconversion offers a promising solution by utilizing these nutrients to produce value-added products, such as microbial biocontrol agents. Bacillus spp. in combination with essential oils, are particularly promising for fungicidal applications. The aim of this study was to investigate the potential of confectionery industry wastewater as a medium for producing the Bacillus sp. BioSol021-based biocontrol agent and to assess the effects of incorporating essential oils into the cultivation medium on bacterial growth and antimicrobial activity against the aflatoxigenic fungal pathogen Aspergillus flavus. Biomass content of Bacillus sp. BioSol021 was measured using the plate count method, while antifungal activity was evaluated using the well-diffusion method. The biomass content of Bacillus sp. BioSol021 during cultivation suggests the potential for utilizing this waste as suitable substrate for microbial growth, as no inhibition was observed. However, the addition of essential nutrients' sources could be considered to enhance bio-mass proliferation. The applied essential oils did not inhibit bacterial growth; rather, thyme and fennel oils increased biomass content compared to medium without essential oils. The highest antimicrobial activity against Aspergillus flavus was observed using oregano oil, followed by basil oil, with maximum activity at 72 hours of cultivation, which also corresponded with the highest biomass content. Future research should focus on further investigating wastewater seasonal characteristics, optimizing bioprocess parameters, and exploring the specific mechanisms of biocontrol action of both the Bacillus isolate and essential oils, as well as their interactions.

The knowledge of the English language, as a global lingua franca is necessary for following professional literature, communicating with foreign business partners, as well as correspondence and various forms of written expression. An important aspect of language education on the higher educational level is learning English for a given purpose. ESP (English for Specific Purposes), as a subfield of the English language, that is distinct and special, is an excellent means for individuals to connect and communicate within a certain profession. The primary objective of a foreign language learning curriculum, utilising a communicative approach, is to equip students with the requisite knowledge and practical skills to effectively communicate in a second language. The aim of this paper is to examine to what extent university students are motivated to learn ESP, as well as to what extent they are aware of the importance of ESP for the profession they have chosen. This paper also aims to determine whether students, who after many years of learning English continue to study it at the university, have any particular expectations from the ESP course in the first year of study, whether there are certain difficulties with the acquisition of professional terminology, as well as to what extent the students are satisfied with the achieved success. The paper employed quantitative research as a research methodology to evaluate the set hypothesis by statistically analyzing numerical data. Questionnaires were used to collect data which then were analysed using descriptive statistics in order to provide exact and reliable information.

This paper represents an attempt to explore the meaning of the term communicative competence in a foreign language and its main components, as well as the importance of its achievement. It starts with different definitions and models of communicative competence, showing how this term came about and how it became the main goal of teaching and learning English as a foreign or second language in many countries. The paper also recommends some activities, which can be of great importance when it comes to mastering English and acquiring communicative competence, when applying a communicative approach in teaching a foreign language.

The aim of this work was to investigate the effect of the commercial formulation hemazin SC 500, an herbicide containing terbuthylazine as the active compound, on the isoenzyme patterns and activities of Cu-Zn superoxide dismutase (SOD1) and catalase (CAT), as well as on the glutathione S-transferase (GST) activity, in human erythrocytes in vitro. The human erythrocytes were treated with hemazin SC 500 over a broad range of terbuthylazine concentrations (37 nmol L-1– –37 mol L-1) for 1 and 3 h at a temperature of 37°C. Native electrophoresis of the control and treated samples revealed two SOD1 and one CAT isoform. Treatment did not affect the SOD1 and CAT isoenzyme profile, but induced a change in their activities. Terbuthylazine at lower concentration induced a significant increase of the total SOD1 activity and decreased the GST activity in samples incubated for 1 and 3 h. On the other hand, the highest increase in the CAT activity was observed for the sample treated for 1 h with a higher concentration of terbuthylazine. Hemazin SC 500 containing terbuthylazine induces changes in the erythrocyte antioxidative system whereby the response of individual enzymatic antioxidants depends on the concentration of the pesticide and the incubation time.

Osmotic dehydration is a process of partial water removal by immersing foods, mostly fruits and vegetables, in hypertonic solutions. During osmotic dehydration, the removal of water from plant tissue is accompanied by the counter diffusion of solutes from the osmotic solution into the tissue. The purpose of this study is to determine the optimal conditions for osmotic dehydration of sugar beet cossettes using desirability function approach. The optimum operating conditions were found to be a temperature of 50 °C, a sucrose concentration of 70 % (without salt) and a treatment time of around 125 min. At this optimum point, a water loss of 46.9 % and a solid gain of 1.4 % were recorded. Relative to temperature minimization, the following optimum point values were determined: a temperature of 30 °C, a sucrose concentration of 61.4 %, a salt concentration of 8 %, and a treatment time of 240 min. In this instance, a water loss of 40.3 % and a solid gain of 0.04 % were recorded, indicating a significantly lower solid gain value compared to the first optimization results.

Experimental studies on the effect of geometrical characteristics (restriction orifice free area and sparger configuration) on the riser gas holdup of an external-loop airlift reactor have been conducted in this paper. The impact of the addition of non-coalescing media, such as n-butanol, was also investigated. In general, the decrease in the restriction orifice free area led to a substantial increase (up to 90%) in the riser gas holdup. The addition of n-butanol effected gas holdup to a lesser extent, as it increased the gas holdup in the range of 4-15%, depending on the restriction orifice free area. On the other hand, the impact of the sparger type was observed only at lower gas velocities, for which the sinter plate increased the gas holdup up to 20% in comparison to the single orifice. The paper also presents an empirical correlation for the estimation of the riser gas holdup with an average relative error of 7%. Finally, a neural network model with an average relative error of 2.4% was proposed. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172025]

This paper presents a multi-objective optimization model by applying genetic algorithm in order to search for optimal operating parameters of microfiltration of baker’s yeast in the presence of static mixer as a turbulence promoter. The operating variables were the suspension concentration, transmembrane pressure, and feed flow rate. Two conflicting objective functions, maximizing the permeate flux and maximizing the reduction of energy consumption, were considered. This multi-objective optimization problem was solved by using the elitist non-dominated sorting genetic algorithm in the Matlab R2015b software. The Pareto fronts along with the process decision variables correspondding to the optimal solutions were obtained. It was found that lower suspension concentrations (2-4.5 g/L), feed flow rate in the range 109-127 L/h, and transmembrane pressure of 1 bar were the optimal process parameters which yielded maximum permeate flux (177-191 L/(m2h)) and maximum reduction of energy consumption (44-50%). Finally, the results were compared with the previously published results obtained by applying desirability function approach. Given that genetic algorithms have generated multiple solutions in a single optimization run, the study proved that genetic algorithms are preferable to classical optimization methods. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-31002]

Continuous adsorption of methylene blue from aqueous solutions onto maize stem ground tissue in column mode was investigated. The study encompassed the effects of important parameters such as flow rate, initial concentration of methylene blue, and bed depth on methylene blue removal from model solutions. The maximum adsorption capacity of the maize stem was 45.9 mg/g at the initial methylene blue concentration of 20 mg/L, bed height of 6.5 cm and flow rate of 8 mL/min. It was found that the breakthrough time for reaching saturation increased with a decrease in the flow rate, and also occurred earlier for a higher influent concentration. The breakthrough times increased with the bed depth, thus allowing a larger volume to be treated. The Adams-Bohart, Yoon-Nelson, Clark and artificial neural network models were used to predict the breakthrough curves. These models gave excellent approximations of the experimental behavior.[Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172025]

Raising a child with a developmental disability can be a serious challenge for parents, which leads to increased parenting stress and has multiple impacts on family well-being. Even though there is a well recognized need for support for parents of children with disabilities, our country lacks the systematized support programs and their evaluations. Program 'Our Story' aims to educate parents about the key processes that lead to accepting the child's condition and recognizing an appropriate care model for a child with disabilities. The program is based on attachment theory and the importance of resolution to diagnosis- emotional and cognitive acceptance of the child's health condition and its implications. It is a structured program, consisting of six thematic meetings with a group of parents. The group counseling is led by two professionals who have previously undergone a 32-hour program for the implementation of training. This paper presents the experiences from two preschool institutions, in which the program was implemented and evaluated. Also it discusses the importance and possibilities of implementing a support program for parents of children with disability in the context of early education system.

The objective of this work was to estimate the effects of the operating parameters on the baker's yeast microfiltration through multichannel ceramic membrane. The selected parameters were transmembrane pressure, suspension feed flow, and initial suspension concentration. In order to investigate the influence and interaction effects of these parameters on the microfiltration operation, two responses have been chosen: average permeate flux and flux decline. The Box-Behnken experimental design and response surface methodology was used for result processing and process optimization. According to the obtained results, the most important parameter influencing permeate flux during microfiltration is the initial suspension concentration. The maximum average flux value was achieved at an initial concentration of 0.1 g/L, pressure around 1.25 bars and a flow rate at 16 L/h. [Projekat Ministarstva nauke Republike Srbije, br. TR 31002]

The effects of the inserted membrane in the downcomer of an external-loop airlift reactor, the gas sparger type (single orifice and sinter plate) and added alcohol (ethanol, n-butanol, or n-hexanol) on the volumetric gas-liquid mass transfer coefficient (kLa) were studied. Due to the presence of the membrane in the downcomer, kLa did not change significantly; the differences were smaller than 10%. The highest values of the kLa were obtained using the sinter plate. It was found that the addition of small amounts of alcohol increased the mass transfer. Using our experimental results and the data of other authors, the feed-forward back propagation neural network for prediction of kLa in external-loop airlift reactors with alcohol solutions was proposed. [Projekat Ministarstva nauke Republike Srbije, br. 172025]

The present study is concerned with two-sided lid-driven incompressible flow in rectangular, deep cavities applying lattice Boltzmann method. After validating the code for the square cavity, solutions for cavities with an aspect ratio 1.5 and 4 were obtained for the Reynolds numbers of 100, 400, 1000 and 3200. The influence of the Reynolds number and aspect ratio on the flow pattern and on the characteristics of vortices inside the cavity was studied. Symmetric flow pattern was obtained for all investigated cases. The middle of the cavity is mostly influenced by the increase in the aspect ratio. Critical aspect ratio, at which the birth of a primary vortex in the middle of the cavity takes place, was determined to be between 2.7 and 2.725. [Projekat Ministarstva nauke Republike Srbije, br. 172025]

The main hydrodynamic characteristics of a novel-constructed, self-agitated draft tube airlift reactor (DT-ALR) were investigated. Ten impellers, driven only by the means of gas throughput and induced liquid circulation, were inserted in the draft tube. The insertion of impellers caused bubble breakup and reduction of both mean bubble size and coalescence, even under the conditions of high gas throughputs. Although the impellers induced energy losses, the resistance to the flow was relatively lower due to their rotation, unlike the internals used in other research reported in the literature. In comparison to the conventional configuration of a DT-ALR, it was found that the presence of impellers led to significant changes in hydrodynamics: riser gas holdup and mixing time increased, while overall gas holdup and liquid velocity in the downcomer decreased. [Projekat Ministarstva nauke Republike Srbije, br. 172025]

The aim of this study is to investigate application of Midilli-Kucuk thin layer drying model for convective and microwave drying of sugar beet pulp. Also air followed by a microwave finish drying was investigated. As the parameter of quality of dried sugar beet pulp water holding capacity was investigated. The drying took place in falling rate period although a short constant period was observed during hot air drying at 65 C. The experimental moisture ratio data were fitted to Midilli-Kucuk model and assess according to three statistical criteria: reduced chi-square, root mean square error and residual sum of squares. This model satisfactorily described the drying characteristic of sugar beet pulp. Water holding capacity was evaluated as the quality parameter. It decreased with increase of drying temperature as well as microwave power. The highest value was obtained for microwave finish drying.

In order to obtain a better heat transfer, it is important to enhance fluid mixing in heat exchangers. Since there are negative effects when heat exchangers are operating in turbulent regime (like significant pressure drop, increased size of the pump) it is necessary to apply the techniques which would provide better fluid mixing when heat exchangers are operating in laminar regime. Investigations have shown that use of sinusoidal instead of flat plates results in this effect. This study is a result of two dimensional simulation of fluid flow between two parallel sinusoidal plates. Simulation was done with the use of modified Openlb code, based on lattice Boltzmann method. Reynolds number was varied from 200 to 1000, and space between the plates was varied from 3cm to 5 cm. Results showed that sinusoidal plates enhance fluid mixing, especially with greater values of Re and smaller space between the plates, which is in agreement with previous investigations.

This paper is concerned with numerical study of the two-sided lid-driven fluid flow in a staggered cavity. The ANSYS FLUENT commercial software was used for the simulation, In one of the simulated cases the lids are moving in opposite directions (antiparallel motion) and in the other they move in the same direction (parallel motion). Calculation results for various Re numbers are presented in the form of flow patterns and velocity profiles along the central lines of the cavity. The results are compared with the existing data from the literature. In general, a good agreement is found, especially in the antiparallel motion, while in the parallel motion the same flow pattern is found, but the velocity profiles are slightly different. [Projekat Ministarstva nauke Republike Srbije, br. 46010]

Belgrade's water supply relies mainly on the River Sava and groundwater supply wells, which are located in the vicinity of the river and Ada Ciganlija. In this paper, the content of aluminum, boron, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, cadmium, barium and lead was analyzed in raw water as well as drinking water distributed by the Water Supply and Sewage of Belgrade. A total of 14 samples were examined from all water treatment plants that are part of the distribution system. The measurements were conducted using the inductively coupled plasma-mass spectrometry (ICP-MS) technique. The aim of this research was to examine the effectiveness of drinking water preparation process in the plants belonging to the Water Supply and Sewage of Belgrade. The content of certain elements varies considerably in raw water (river and groundwater): the concentration of boron in river water is two to three times lower than the concentration in groundwater; the concentration of arsenic in river water is ten to twenty five times lower than the concentration in groundwater; the concentration of aluminum in all groundwater samples was below the detection limit of the instrument (0.50 μg/dm3), whilst in the river water the content of aluminum was about 50 μg/dm3 and the concentration of manganese in the river water was up to 10 times lower than the concentrations in groundwater. In all drinking water samples the concentration of the elements were bellow the maximum allowed levels according to the Serbian regulations. Correlation coefficients determined for boron, manganese, cobalt, nickel, copper, zinc, arsenic, barium and lead, which were analyzed in raw waters, show that four groups of elements can be distinguished. Boron, manganese, arsenic and barium are related to each other and probably have a common natural origin; copper and lead probably have a common anthropogenic origin; correlation of nickel and cobalt was observed, while zinc was not in correlation with any other element.

This paper is concerned with numerical study of fluid flow through a pair of corrugated platest. The aim was to observe and understand the behavior of the flow and vortex formation through channels where the fluid is subjected to a periodic increase and decrease in cross-section area. The plates modeled for the study had sinusoidal profiles. A pair of plates with 180° phase shift was simulated in two-dimensional spaces. The Reynolds number was a function of the average plate spacing (Havg) and the laminar flow velocity and it was in the range between 200 and 1000.

Membrane process efficiency in the dairy industry is impaired by the formation of deposits during filtration processes. This work describes cleaning procedures for ceramic tubular membrane (50 nm) fouled with whey proteins. Also, mathematical modelling was performed to obtain models which allow deeper insight into the mechanisms involved during cleaning procedures. The caustic solutions (0.2%w/w, 0.4%w/w and 1.0%w/w NaOH) and the mixture of two commercial detergents (0.8%w/w P3-ultrasil 69+0.5% w/w P3-ultrasil 67 and 1.2% P3-ultrasil 69+0.75 P3-ultrasil 67) were used as chemical cleaning agents. The results showed that the best flux recovery was achieved with 0.4%w/w NaOH solution. After analyzing the experimental data, five parameter and six parameter kinetic models were suggested for alkali and detergent cleaning, respectively. The changes of total and specific resistances, as well as the change of the effective pore diameter and deposit thickness during cleaning are estimated by applying these models.

Efficiency of membrane processes is greatly affected by the flux reduction due to the deposits formation at the surface and/or in the pores of the membrane. Efficiency of membrane processes is affected by cleaning procedure applied to regenerate flux. In this work, flux recovery of ceramic tubular membranes with 50 and 200 nm pore size was investigated. The membranes were fouled with reconstituted whey solution for 1 hour. After that, the membranes were rinsed with clean water and then cleaned with sodium hydroxide solutions or formulated detergents (combination of P3 Ultrasil 67 and P3 Ultrasil 69). Flux recovery after the rinsing step was not satisfactory although fouling resistance reduction was significant so that chemical cleaning was necessary. In the case of 50 nm membrane total flux recovery was achieved after cleaning with 1.0% (w/w) sodium hydroxide solution. In the case of 200 nm membrane total flux recovery was not achieved irrespective of the cleaning agent choice and concentration. Cleaning with commercial detergent was less efficient than cleaning with the sodium hydroxide solution.

Background: Objective of the study was to determine the differences in distribution of the most important nutritional risk factors for cancer among healthy population of Niš, men and women, in order to carry out adequate measures of prevention. Methods: 388 people were involved in the study, randomly selected and they completed the authorized questionnaire concerning their eating habits, marital status and smoking habits. Body mass index was determinated also. Participants’ nutritive profile concerning risk factors was determined by giving points to each factor such as number of daily portions of fruits, vegetables, and cereal, daily intakes of red meat, table salt, and alcohol and obesity. χ2-test was applied to determine if there is statistically significant difference among risk factors concerning sex and marital status. Student t-test was applied to determine if there is statistically significant difference among medium values of points of risk concerning sex and marital status. Results: According to the results, the population of Niš is at medium risk for cancer. The number of points between 18 and 27 was considered medium risk. Women are at lower risk to develop cancer than men (t=6.66, p>0.01), regarding nutritional risk factors, the some for singles (t=2.38, p>0.01). Vegetables (χ2=3.29, p

Background: Colon and rectal cancers (CRC) accounted for 783.000 new disease cases (9.7% of the world total), and was a cause of 437 000 deaths (8.4% of the world total). Unlike the situation with most disease sites, incidence and mortality were not much different between men and women (ratio 1.05:1.00). In terms of incidence, CRC rank thirds in frequency in men (after prostate and lung) and third in women (after breast and lung). Methods: In the Hospital Cancer Registry of the Clinic of oncology Niš, for the period 1998-2002 there were 7873 registered new cancer cases. The authors searched the registry with aim to establish the number of patients affected with colorectal cancer for the observed 5-year period, to establish the most frequent cancer site, histopathologic diagnosis, age distribution of the disease, and tumor burden in the registered cases. Results: CRC participates with 10.24% of all cancers cases. There were 1329 gastrointestinal cancer cases, out of which 806 (61%) colorectal cancer cases. CRC ranks first in frequency in men (18% at all cancers in men), and fifth in women (5.96% at all cancers in women). The disease was predominant in male population (504/806 men and 302/806 women; ratio 1.67:1.00). The youngest two cases were in the group of patients aged from 20 to 24 years. The number of CRC increases with age for both genders (68 men and 39 women aged 50-54 years), and the highest number of patients were observed among persons aged from 65-69 years (95 men and 52 women). Colorectal cancers most frequently arise in the rectosigmoid colon portion (89 cases; 22%), then in the colon transversum (72 cases; 18%), colon ascendens (73 cases; 18%) cecum (48 cases; 12%), sigmoid colon (31 cases; 7.7%), hepatic flexura (26 cases; 6.5%), lineal flexura (12 cases; 3%) and colon descendens (8 cases 2%). The most common histopathologic diagnoses are: Adenocarcinoma 685 (85%), Ca papillare 69 (8.6%), Ca mucinosum 43 (5.3%), Ca planocellulare 8 (1%), Ca lucidocellulare 4 (0.5%), and sarcoma 2 (0.2%). Conclusion: The analysis of the period showed the increase of the number of cases (133 patients in 1999 and 241 cases in 2002). CRC makes up 61 % of all gastrointestinal cancers. The most frequent localization was rectum (393/806; 49 %) These tumors most commonly occur in rectum and sigmoid colon (89/401). Colon descendens is rarely affected (8/401). The most predominant type was adenocarcinoma (685/806). CRC was 1.67 times more frequent among men then among women.