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In the food industry, convective drying is a widely used method due to its applicability to many food materials. Besides this advantage of the convective drying method, there are several shortcomings related to the rehydration capacity, low quality of dried material, loss of color, flavour, and nutrient of the final dried materials. In this paper, the convective drying kinetics of osmotically pre-treated potato slices (variety Carrera) were analyzed. Thin-layer drying kinetics of potato slices at four drying air temperatures 40, 50, 60 and 70°C and two drying air velocities 1 and 2 ms-1 were obtained on the experimental setup. For an approximation of the experimental data with regard to the moisture ratio three thin-layers drying, models from scientific literature and the model of Mitrevski et al., were used. For each model and data set the statistical performance index, ph chi-squared, and ch2, values were calculated and models were ranked afterward.

Numerous mathematical models for approximating the water sorption data of food materials are available in the scientific literature. Depending on the number of parameters included, such models are referred to as one-parameter, two-parameter, three-parameter, or multi-parameter models. The objective of this study was to evaluate a total of sixty two-parameter sorption isotherm models for approximating the equilibrium moisture content data of quince and to compare the goodness of fit between the models examined. On the basis of the statistical analyses performed, it can be concluded that the Popovski&Mitrevski model has the best statistical performance of all the models examined. The coefficient of determination was the main criterion for assessing the model performance, totalling R2 = 0.9913 for the best model performance.

The mathematical modelling of the food drying process is of significant importance to scientific and engineering calculations. Thin-layer drying models represent valuable tools for modelling the drying curve and estimating the drying time. These models have wide application due to the ease of use and requirement of less data compared to complex mathematical models. In this paper, the thin-layer drying kinetics of some fruits (namely, pear and quince) was studied. Using an experimental setup designed to simulate an industrial convective dryer, the experimental results were obtained at five drying air temperatures (30, 40, 50, 60 and 70 oC) and three drying air velocities (1, 1.5 and 2 ms-1). For the approximation of the experimental data with regard to the moisture ratio, a new thin-layer model was developed. The performed statistical analysis shows that this model has the best performance features compared to other well-known thin-layer drying models found in the scientific literature.

In this paper, a faster and easier way, in comparison with classical methods, to determine the equilibrium moisture content in food materials is shown. The equilibrium moisture content is determined only experimentally, with determination of sorption isotherms. However, the key issue that is a condition for application of certain experimental method for determining of sorption isotherms is the reliability of experimental data obtained for equilibrium moisture content, as well as the time required to determine specific sorption isotherm. Despite numerous advantages of the static gravimetric method, the long time to achieve equilibrium moisture content of the sample is its main drawback and reason why the researchers use other techniques and methods. Out of these reasons came the idea to apply relatively fast and simple method to determine equilibrium moisture content in food materials, based on the values of average material temperature change obtained from experiments including convective drying kinetics. Furthermore, the resulting temperature response from the conducted experiments can be successfully used to determine unknown parameters in the models for calculation of equilibrium moisture content, by applying of inverse approach method that is an essential tool in modeling of heat and mass transfer processes for different food materials.

In this paper, a mathematical model of far-infrared vacuum drying of shrinkage body is presented. The system of two coupled partial differential equations for heat and mass transfer with appropriate initial and boundary conditions are solved numerically with used of the finite difference method. On the basis of the numerical solutions a computer program for calculation of temperature profiles, transient moisture content, mid-plane temperature, and the volume averaged moisture content changes for given drying regime was developed. For verification of the mathematical model a series of numerical drying experiments of potato slices were realized.

Water activity is an important parameter that can be used to predict the stability and safety of food with respect to the most microbiological and biochemical reactions, conditioned by its value. In other words, it describes the degree of the bound level of water in the dry material, as well as the indicator of the ability of water to act as a solvent, participant in various biochemical reactions, or growth of different microorganisms. The determination of the minimum value of water activity that allows the growth of certain microorganisms and mechanical and thermal equilibrium of the material with the surroundings, are the most important parameters that characterize the stability of the material. The equilibrium moisture content has fundamental role in food industry and technology from the aspect of design and optimization of drying processes and equipment, design of packing materials for dried products, prediction of quality and stability, as well as for calculation of changes in the moisture content of dried material during its storage. Considering the relationship between these two physical parameters, their interdependence has been shown in this paper.

In this paper the thin-layer drying of quince slices as a function of drying conditions were examined. The experimental data set of thin-layer drying kinetics of quince at five drying air temperatures 30, 40, 50, 60 and 70 oC, and three drying air velocities 1, 1.5 and 2 m s-1 were obtained on the experimental setup, designed to imitate an industrial convective dryer. Ten well known thin layer drying models from scientific literature were used to approximate the experimental data in terms of moisture ratio. In order to find which model gives the best results, the numerical experiments were made. For each model and data set, the statistical performance index (φ) and chi-squared (x2) value were calculated and models were ranked afterwards. The performed statistical analysis shows that the model of Hii gives the best results for approximation of experimental drying data of quince.

This paper describes the experimental results on the drying of the apple slices by infrared radiation under vacuum condition. The investigation of vacuum far-infrared drying processes was conducted on the experimental set-up that is designed to imitate industrial batch dryer. The experimental conditions have been chosen such that heaters temperature and absolute chamber pressure have been in the range used on the industrial dryer. Apple slices were dried at four vacuum pressures 20, 40, 60 and 80 kP and five temperature of heatres, 120, 140, 160, 180 and 200ºC which were kept constant during the single experiments. Based on experimental drying data, it was found that the drying time decreased with an increase of temperature of heaters and the decrease in the absolute chamber pressure. It was also concluded that the influence of the temperature of heaters has more significant effect on reducing of the drying time than the vacuum pressure.

The main idea of this paper is to review and present the papers in which sorption isotherms of different types of materials were determined. For this purpose, the number of publications, references, etc., in the most frequently used journals for publications of sorption isotherms papers were studied. In order to obtain clear picture what is realistic to expect from the scientific investigation in fields of determination of sorption isotherms for different materials in the near future and where future research should be focused, some statistical analysis were made. The papers have been classified into nine categories: I. Papers in which determination of sorption isotherms of fruits are performed; II. Vegetables; III. Tea, Herbs, Coffee and Tobacco; IV. Pistachio nuts, Almond, Soybeans and Cereals; V. Flour, Pasta and Powder milk; VI. Meat and Fish; VII. Foodstuffs; VIII. Wood, Paper and Clay and IX. Pharmaceutical materials. From the performed analysis it was concluded that the categories of papers 'Foodstuffs ', 'Fruits ', 'Pistachio nuts, Almond, Soybean and Cereals ', 'Vegetables ' and 'Flour, Pasta and Powder milk' comprise 75.6% of the published referent papers. The remaining categories of papers for 'Tea, Herbs, Coffee and Tobacco', 'Meat and Fish', Wood, Paper and Clay ' and 'Pharmaceutical materials ', are 24.4% of the referent papers. For this reason, future research should be focused of determination of sorption isotherms of these materials.

The main idea of this paper is to review and present the scientific papers in which inverse approach was used. For this purpose, the number of publications, references, etc., in ten relevant journals (Journal of Food Engineering, International Journal of Heat and Mass Transfer, Inverse Problems in Science and Engineering, International Journal of Food Properties, Computers & Mathematics with Applications, International Journal of Thermal Sciences, Drying Technology: An International Journal, International Journal of Food Science & Technology, Journal of Engineering Physics and Thermophysics, LWT - Food Science and Technology) were studied. In order to obtain clear picture of what is realistic to expect from the scientific investigation in this field in the near future and where future research should be focused, some statistical analysis were made. From the performed statistical analysis it was concluded that more investigations are needed for determination of the thermopysical and engineering characteristics of food materials.

In this paper, the results of comparative analysis between transcendental and cyclometric sorption isotherm models are presented. In order to find which model gives the best results, some numerical experiments were made. The experimental data set for equilibrium moisture content and the water activity for apple, pear, kiwi and banana at two different temperatures were used from the scientific literature. For each model and data set, several statistical parameters were calculated and models were ranked afterwards. The performed comparative analysis shows that the cyclometric models in many cases have higher values of the coefficient of determination, and lower values of the root mean squared error and the mean relative deviation than transcendental the isotherm models. All these results show that the cyclometric sorption isotherm models give the best overall fit to experimental data. After choosing the best transcendental and cyclometric model with the high value of statistical performance index, the residual plot was checked graphically.

In this paper a research is made by analyzing the noise level variations in the area of city Ohrid. City of Ohrid is one of the 28 sites that are part of UNESCO's World Heritage of Cultural and Natural treasures and it is also the largest city on Lake Ohrid, making it a vast tourist attraction. One of the main complaints by the tourists during the tourist season is the level of noise that is produced by several sources. For better understanding and analyzing the noise pollution in the environment, two kinds of research are made. Firs research is made by public survey and the second one is made by measurement of the level of noise produced in specific locations that are most frequent with visitors. A set of measures are made for reducing the noise pollution, making better environment and improving locals and tourist accommodation. [ABSTRACT FROM AUTHOR]

In this paper the critical activities for health and safety at work during working operations for assembly/disassembly of parts under pressure were detected. After that protective measures during loading, unloading and transportation of elements at height and protective measures during working at height were discussed. Thermal power plant (TPP) Bitola is the largest electricity producer in the Republic of Macedonia with installed capacity of 3x225 MW, which provides 80 % of the total energy production in the Republic of Macedonia, with average annual production 4.200 GWh. Rehabilitation and performance improvement for TPP Bitola are provided to modernization and revitalization of turbines, generators and automation, revitalization and modernization of the boilers with NOx emissions reduction and revitalization of cooling towers, and revitalization for SOx, dust and particle emission reduction. Taking this into account in this paper some safety measures at work during the execution of assembly and disassembly works of parts under pressure, boiler casing and assembly of pipeline components with air under pressure were discussed. [ABSTRACT FROM AUTHOR]

Measures for increasing of energy efficiency in buildings are closely related to Energy Audit. Faculty of technical sciences - Bitola (FTSB) is one out of five companies that were chosen as educating facilities for training of energy auditors. High School dorm "Mirka Ginova" in Bitola is the only state-owned dorm in the city. Preliminary energy audit for the nearby building of the dorm was performed as a part of the training for energy auditors. The calculations were performed by using of ENSI© EAB software. [ABSTRACT FROM AUTHOR]

In this paper, some of the statistical indicators which refer to serious and fatal accidents at work in the European Union (EU-28) and in the Republic Macedonia are presented. The performed statistical analysis shows that the number of serious and fatal accidents at work in EU-28 and in the Republic Macedonia, in 2012 was decreased in comparison with 2008. Nevertheless, the Republic of Macedonia has high incidence rate for fatal accidents at work compared to highly develop European countries. The activities of public administration and defense, construction, manufacturing, transportation and storage sector and the activities of households as employers are the economic sectors in which it is possible to prevent injuries caused by serious accidents at work. The activities of households as employers, construction sector, transportation and storage sector and agriculture, forestry and fishing are the economic sectors in where prevention of injuries at work caused by fatal accidents must be addressed. [ABSTRACT FROM AUTHOR]

The subject of this paper is to give a brief overview of the risk assessment for the scaffolds and ladders workers as part of the risk assessment for the project comprising building of new motorway from the town of Demir Kapija down to the village of Smokvica, Republic of Macedonia. That is the last un-upgraded section of the existing motor road/motorway E-75, that runs through the Republic of Macedonia and connects Republic of Serbia and the Republic of Greece. Construction of the remaining section of this motorway will enable faster and more safe transportation of people and goods from Central Europe to Greece, or to Turkey and Near East since it will be connected to "Via Egnatia" (West-East) motorway in Greece. Team from the Faculty of Technical Sciences - Bitola prepared risk assessment for the whole project comprising 30 different work places and is constantly is engaged as a consultant for Health and Safety at work related issues, [1]. According to identified risks (hazards) during works on the bridge constructions, scaffolds and ladders used very often and there is proposed some recommendations to reduce or eliminate these risks of falling from high. [ABSTRACT FROM AUTHOR]