Хранителен инженеринг

Секция „Приложна математика и статистика за ХВП и биотехнологичната промишленост”

Soft computing techniques as statistical tools
Софт компютинг техники като средство за статистически анализ
Soft computing is a branch of mathematics and computer sciences, which received a great attention in the last years. The main techniques of soft computing are machine learning (neural networks and support vector machines), fuzzy logic, evolutionary computation and probabilistic reasoning. Each of these techniques suggests different aspects of data analysis. In this paper, neural networks and fuzzy logic as statistical tools for data analysis are proposed and discussed. Nonlinear regression model based on neural network and fuzzy logic is shown. The similarity between backpropagation learning algorithm and the classical method of least squares is presented.
Автори: Маргарита Терзийска, Мария Добрева

Секция „Процеси и апарати за ХВП и биотехнологичната промишленост”

This paper presents CFD-simulation results concerning the flow behaviour in a dead-end filtration cell. The CFD modelling is focused on an experimental dead-end stirred membrane cell – velocity and shear stress distribution on the membrane surface and the effect of stirrer speed on the latter. Existing experimental observations relating permeate flux and stirrer speed are discussed in the scope of operating conditions affecting membrane fouling during nano- and ultrafiltration of biologically active compounds from plant extracts. Velocity and shear stress distribution on the membrane surface are compared for dead-end and cross flow filtration cell. They are discussed in view of the observed flow behaviour during dead-end and cross-flow nanofiltration, applied for concentrating antioxidants (polyphenols and flavonoids) from ethanolic extracts of Sideritis ssp and tobacco waste. The permeate flux decline with membranes of MWCO 300- 500 Da is presented and related to the mechanism of fouling. Keywords: dead-end stirred cell, membrane filtration, flow behaviour, CFD modelling, extracts of natural products.
Автори: Даниела Джонова - Атанасова, Стела Паньовска, Ирен Цибранска

Structural Anomalies in a Stirred SMBR Relevant to Immersed Membranes Use
Структурни аномалии в хидродинамиката на мембранни биореактори (МВR) с разбъркване с отношение към употребата на потопяеми мебрани
Separation of value-added food additives, such as antioxidants, is often practiced by micro and ultrafiltration membranes in integrated submerged membrane bioreactors (SMBR) and flow conditions are of major importance for their performance. In hybrid vessels immersed membranes affect fluid circulation and may cause operational deterioration. The flow structural deterioration at integrated (production and separation) biological reactors with submerged membrane modules is addressed. Membranes of tubular one-channel type used for microfiltration to separate biomass from a process fluid are considered. Contemporary CFD methodology is used and CFD simulation analysis of the structural changes in the mixing bioreactor, a dual impeller flat-blade or curved-blade type, is carried out. 3-D “k-ε” turbulent flow model is used and 3-D solid body diagrams are worked out to illustrate cases at critical fluid consistency of 0.1Pa.sn and critical gas flow rate of 2vvm. Zones at the immersed membranes that are risky for membrane fouling are revealed. Two types of anomalies due to (1) non-Newtonian component presence, and (2) to extreme gas flow rate, are examined. The corresponding performance parameters, gas volume fraction and fluid surface velocity, characteristic for the specific “pathological” performance of restricted fluid mobility in the vicinity of membrane walls are discussed. Ranges of input parameters referring to power law non-Newtonian fluids of any flow index n<1 at consistency ~ 0.1Pa.sn that could lead to membrane malfunction are revealed. Keywords. Mixing, Membrane bioreactors, Fluid flow, CFD model analysis
Автори: S.D. Vlaev I. Tsibranska D. Dzhonova-Atanasova R. Popov

The scientific interest in the efficiency of packed bed columns is part of the world-wide pursuit of sustainability of processes. The packed columns are typical apparatuses for absorption, desorption, rectification and direct heat transfer with applications in power industry, biofuel technologies, and food production. The maldistribution of the phases in the apparatus reduces the efficiency and makes difficult the prediction of process performance and scaling up. In the present work the operation of liquid distribution devices and high performance packings are investigated addressing the reasons for hydrodynamic nonuniformity of the liquid phase, including the formation and development of wall flow. Data are obtained from semi-industrial size experimental studies and mathematical modelling of the liquid flow through a layer of random Raschig Super-Ring packing. The effect of measures for ensuring uniform initial liquid distribution in the column apparatus is evaluated and the parameters in the mathematical model are identified. Keywords: packed bed column, liquid distribution, Raschig Super-Ring, random packing, mathematical modeling.
Автори: Daniela Dzhonova-Atanasova, Krum Semkov, Tatyana Petrova, Simeon Darakchiev, Konstantina Stefanova, Svetoslav Nakov, Roman Popov

Application of FlowSimulation software product in the food industry
Приложение на софтуерният продукт FlowSimulation в хранителната промишленост
Computational Fluid Dynamics abbreviated as CFD is part of fluid mechanics that uses numerical methods and algorithms for solution and analysis of problems including fluid flows. Up to 80% of product development costs are determined by decisions taken earlier in the design process. Preliminary simulation enables informed choices, reduces costs for physical prototypes, avoids inaccurate projects in the work process and brings innovation to the market faster and at less cost. There are many CFD software products, each with its specific features, advantages and disadvantages. An example of this type of software is Flow Simulation which is a sub-program (application) to the program for three-dimensional design-Solid Works. The present work explores the possibilities for model studies of FlowSimulation in the food industry including: Optimization of transmission processes in heat exchangers; Optimization of the geometrical shape of stream section to heat exchangers with the purpose of hygienic design; Optimization of the geometrical shape of stream section to valves, gate valves and fittings with the purpose of hygienic design; Investigation of processes when mixing different fluids; Investigation of аerodynamics and temperature distribution in dryers, Refrigeration chambers and warehouses for storing food products; Catering establishments. The following conclusions from the survey were drawn: Information on the use of FlowSimulation in the food industry is still scarce; Recent years there have been increasingly successful attempts to use the software product in the food industry; Due to the continual development of the application by Dassault Systemes there is a tendency to expand the capabilities of FlowSimulation for use in food industry.
Автори: Пламен Райнов

Секция „Машини и апарати за ХВП и биотехнологичната промишленост”

Density and expansion index of extrudates from corn semolina flavored with cocoa flakes
Плътност и експанзионен индекс на екструдати от царевичен грис овкусени с какаови люспи
Extrusion of corn semolina and miled cocoa flakes for flavoringusing a single screw extruder Brabender 20DN was carried out. Full factorial experiment 22 was used to investigate the effect of the quantity of cocoa flafes and moisture of the material on the density and expsnsion index of extrudates. Feed screw speed and screw speed were fixed at 40 and 200 rpm, respectively. Compression ratio of the screw was 4:1. Temperatures of the feed, II-nd and III-rd zone were 150, 155 and 160 °C. The obtained results show that moisture of the material stronger influence on the density and expansion index of extrudates. The increase in moisture content from 14 % to 20 % leads to a decrease expansion index, while density of extrudates an increase.
Автори: Нешо Тошков, Иван Панчев, Апостол Симитчиев, Венцислав Ненов

Process characteristics under single screw extrusion of corn semolina and cocoa flakes
Процесни характеристики приедношнеково екструдиране на царевичен грис и какаови люспи
Extrusion of corn semolina and miled cocoa flakes for flavoringusing a single screw extruder Brabender 20DN was carried out. Effects of cocoa flakes content and feed moisture content on the some process parameters – the flow rate, torque, temperature on extrusion and specific mechanical energy. Full factorial experiment 22 with combinations of cocoa flakes content (5, 10 %) and moisture content (14, 20 %) was applied. Feed screw speed and screw speed were fixed at 40 and 200 rpm, respectively. Compression ratio of the screw was 4:1. Temperatures of the feed, II-nd and III-rd zone were 150, 155 and 160 °C. The obtained results show that moisture of the material stronger influence on the flow rate, torque, temperature on extrusion and specific mechanical energy.
Автори: Нешо Тошков, Иван Панчев, Апостол Симитчиев, Венцислав Ненов

Секция „Електроника и електротехника, приложими в ХВП и биотехнологичната промишленост”

Sampling Time Variation of the EK-H5 Relative Humidity Data Acquisition System
Вариация на периода на дискретизация на система за събиране на данни за относителна влажност EK-H5
Experimental studies often require the registration of a certain number of physical quantities (temperature, humidity, CO2 concentration, etc.). Usually data acquisition systems (abbreviated with the acronym DAQ), are used for this purpose. The main objective of the present study is to investigate and evaluate the variation in the sampling time of the EK-H5 humidity data acquisition system, offered by the company Sensirion. It has been found that during the operation the sampling time changes randomly following the Bernoulli distribution, with the actual values being equal to or greater than the selected value. At a selected value of 100 ms, the probability of the sampling time assuming the same value is about 0,3 and a value of 110 ms - near 0,7.
Автори: Пламен Ив. Никовски, Божидар Г. Марков, Николай Ст. Дойчинов

Секция „Автоматизация на процесите в ХВП и биотехнологичната промишленост”

Control of fermentation process in Biovet AD - Peshtera
Управление на процеса ферментация в Биовет АД – гр. Пещера
For the control of the fermentation process in Biovet AD - Peshtera, a computer control system has been implemented. The aim of the work is to examine the fermentation process in Biovet AD - Peshtera as a control object and to make a brief description of a computer integrated control system Delta V. The work also examines the synthesis of PID controller with additional adjustable coefficients and . Transitional processes have been obtained by assignment for different values of coefficients and . Decreasing the efficiency of P- and D-components at input impact by assignment through different coefficient values of и leads to reducing the magnitude of the first maximum over three times ( = 0.6 °C, 0.22 °C and 0.18 °C) at close times adjustment time ( = 54 min, 68 min and 56 min).
Автори: Петър Василев , Жеко Стойчев , Георги Терзийски

Factors determining the process of acetic acid fermentation as a control object
Фактори определящи процеса на оцетнокисела ферментация като обект за управление
The report examines the main factors influencing the process of acetic acid fermentation. An analysis is made which ones determine the process as a control object. Their importance is assessed for the purposes of control and optimizing the process of acetic acid fermentation. Concerning the composition of the nutrient medium, a passive experiment of 230 observations for two industrial acetators was carried out. In laboratory conditions the effect of fermentation temperature ф, aeration of the medium, amount of yeast and the way of supplementation of the acetate in the semi-continuous method of work on the basic technological and kinetic parameters were investigated. For example, for ф oxidative power  is high for all temperatures and depends heavily on it. We found a decrease at ф = 28 С by over 40%. The maximum growth rate м rises to 28 ° C over two times and then almost does not change. With an increase of ф, the time tп constantly decreases, i. the process is intensifying. This reduction is over 22%. There is a slight rise and then a sharp decrease, nearly four times, for tлф to 28 ° C.
Автори: Жеко Стойчев , Георги Терзийски

An approach for engineering tuning of PID controller with dynamic object from second order
Един подход за инженерна настройка на ПИД регулатор с динамичен обект от втори ред
An approach is for engineering the PID controller with a dynamic object from second order proposed. There is a proposal to solve the problem by solving the characteristic equation. As a result of the third row dynamic system analysis, the adjustment parameters of the PID-controller are calculated. The transition processes of the closed system (object - controller) are dealt with by reference and interference. For the transition process by reference, a sigma overregulation is obtained equal to 4%. If a comparison of prereduction of the transition process by reference (obtained in simulation) is made, 0.6% inaccuracy is observed in theory. Therefore, the proposed engineering approach to a PID-controller with dynamic object from second order is suitable for use in third-line dynamic systems analysis.
Автори: Georgi Terziyski

Dynamic system of linear induction motor -flexible load
Динамична система линеен асинхронен двигател-гъвкав товар
This paper explored dynamical system of linear induction motor-flexible load. The dynamic system describing the linear induction motor in the d, q coordinate system. The additional forces associated to linear induction motor. Flexible load is shown as a two-mass load system. The behavior of the resulting dynamic model is verified simulation. Keywords: linear induction motor, two-mass model, dynamic system, linear velocity

Stand for control of DC motor
Стенд за управление на постояннотоков двигател
The purpose of this article is to present a laboratory stand for control of DC motor with PID regulator. The graphical and control interface has been developed in the Matlab environment. The object of the study is a DC motor with a built-in tachogenerator whose speed will be contorled value. The load of the DC motor is another DC motor coupled to the first one, which rotation is the opposite direction of rotation relative to the controlled motor. Two PID regulators are implemented. The one is constructed on the base of microprocessor, and the other on the base of operational amplifiers. Keywords: DC motor, tachogenerator, stand for control, PID regulator, microprocessor control
Автори: Борислав Вълков, Божидар Марков-УХТ Пловдив

Comparative survey of the paid access web servers and creation of one’s own server.
Сравнително изследване на web сървърите с платен достъп и създаването на собствен сървър.
The study examines the different types of servers and their operating systems, the installation and configuration of a company’s or a person’s own server. The focus is on the choice of the most suitable kind of server for the creation of web systems, web applications, corporate websites, web platforms, shops, forums, etc. The financial aspects affecting the choice and the benefits and disadvantages of the two solutions are also considered. A survey is made of the methods and means of server protection against unauthorized access.
Автори: Христо П. Динков, Стоянка Н. Маджарова, Ева Д. Димитрова,

Features Extraction for Pollen Recognition using Gabor Filters
Особености на извличане и разпознаване на полени използвайки филтри на Габор
The aim of the article is to investigate the feature extraction from microscope images of pollens for a classification of honey on the basis of its botanical origin. A filter-bank of Gabor filters (as a biologically inspired recognition system) is used to obtain features, which are then post-processed using normalization, down-sampling (by bicubic interpolation), and principal component analysis (PCA). PCA is used for reducing the features size and a proper visualization of the feature extraction results. To illustrate the capability of the proposed approach microscope images from the European pollen database, including pollen images of linden, acacia and lavender, are used. The accuracy of the recognition algorithm is evaluated by the one-out cross-validation test conducted in the MATLAB environment.
Автори: Dimitar Nikolov, Diana Tsankova

Modelling of the Electrical Conductivity of the Dilution of Bulgarian Linden Honey
Моделиране на електрическата проводимост на разреждането на български липов мед
Linden honey is among the most common monofloral types of honey in the region of Bulgaria, and it has no reference values for its electrical conductivity (EC) in the international and national standards. Three variants of a model of the EC dependence on the concentration of linden honey (Gaussian, quadratic and cubic function based ones) are proposed. A standard temperature-compensated (at 250C) EC meter is used to capture experimental data. Then the EC readings are calculated to that temperature specified in the honey standard (200C) using a linear temperature compensation coefficient related to honey (2.6 %/ 0C). Verification of the proposed models and their statistical evaluation is done in MATLAB environment. The models can be further developed, summarized and used as an additional tool for the classification of honey on the basis of its botanical and/or geographical origin.
Автори: Svetla D. Lekova, Georgi P. Terziyski, Diana D. Tsankova

Секция „Енергетика и енергийна ефективност на ХВП и биотехнологичната промишленост”

Choice of Operating conditions of a sulfide and nitrate fuel cell for environmental purposes.
Избор на работни условия на горивен елемент с екологична насоченост на базата на сулфиди и нитрати.
Тhe ecology protection together with the use of renewable energy sources are both high priority areas in our days. A new tendency is to eliminate the pollutants in a fuel cell with producing electrical power in the same time. The aim of the present work is to determine the operating conditions of a sulfide and nitrate fuel cell for environmental purposes. The concentrations of the pollutants, the type of the membrane as well as the conductivity of the sulfide solution are studied. Key words: fuel cell, sulfides, nitrates, operating conditions
Автори: E. Razkazova-Velkova, M. Martinov, S. Stefanov

Improving energy balance in a sunflower oil mill
Improving energy balance in a sunflower oil mill
The energy utilization in sunflower oil industry may be improved by better use of biomass resources as sunflower husk, but the effective convenience of this opportunity should be energetically and economically demonstrated for each case study. In this paper energetic and economic impacts of sunflower oil mill are evaluated, considering a better energetic utilization of biomass residue in an advanced energy generation system. One tone of sunflower seeds contains about 170 kg of husk. The energy content of sunflower husk is about 14880 kJ/kg (lower heating value). The sunflower husk is currently directly burnt in boiler to generate saturated steam of 6 bars. By gasification of sunflower husk and the use of resulted syngas in a gas turbine co-generation system, the use of biomass residues can be improved contributing to primary energy saving of the agro-food industry. The analysis has highlighted that the gasification of sunflower husk and use of resulted syngas in a gas turbine co-generation system instead of direct burning in steam boiler improves energy balance and environmental impact (greenhouse gases). Finally, an economic analysis is performed to estimate the economic effort and the payback period.
Автори: Ion V. Ion, Florin Popescu

Analysis of the results of Energy Efficiency Project in the University of Food Technologies
Анализ на резултатите от проекта по енергийна ефективност на Университета по хранителни технологии
Abstract: Energy audit of 3 of educational buildings of the University of Food Technologies (UFT) has been done. А project for renovation of these buildings has been developed and accomplished on this basis. The data from the invoices for heating of these buildings for five years after the project accomplishment have been collected and analyzed. The results show reducing of primary energy consumption by 1460,186 MWh/y and of the CO2 emissions by 325,733 tons/y. UFT has received certificates of these savings and they can be traded in the coming years and bring financial income to the University.
Автори: Георги Вълчев, Никола Калоянов, Виолета Рашева, Минчо Минчев, Станислава Ташева

Секция „Компютърни системи и технологии за ХВП и биотехнологичната промишленост”

Open-source software products for microbiological analyses
Софтуерни продукти с отворен код за осъществяване на микробиологични анализи
This paper presents an overview of most popular open-source software products for performing of microbiological analyses. All of the presented programs are based on popular techniques for digital image processing and computer vision algorithms. The main idea is to make a research and acquaint in depth with the existing open-source computer programs and try to make upgrades on them or to develop a new one.
Автори: Ангел Данев, Радослава Габрова

Solving optimization problems in MS Excel
Решаване на оптимизационни задачи в MS Excel
An optimization problem is one where it is needed to select a best element (with regard to some criterion) from some set of available alternatives. Optimization often is referred to as mathematical programming, which is a field of management science that finds the optimal or the most efficient way of using limited resources to achieve the objectives of an individual or a business. In the simplest case, an optimization problem consists of maximizing or minimizing a real function by systematically choosing input values from within an allowed set and computing the value of the function. The optimization helps to solve different types of problems: determining product mix, financial planning, routing and logistics and so on. The aim of this paper is to show how such optimization problem can be solved with Excel\'s Solver add-in.
Автори: Маргарита Терзийска, Мария Добрева

Digitizing the readings of an analog pointer device in programing environment LabVIEW
Цифровизиране показанията на аналогов стрелкови уред в програмна среда LabVIEW
A method for transforming readings of analog pointer device in digital form is presented. For this purpose Brabender farinograph to test the strength of the flour is used. A program in the LabVIEW environment is developed. A comparison of the data of a farinogram obtained on paper and as a result of the program-implemented method is presented. The method can be successfully applied to each linear scale machine.
Автори: Христина Т. Андреева, Лена Ф. Костадинова-Георгиева, Недялко T. Катранджиев