Месец: януари 2022

Кey Words: Wooden prisms; veneer production; autoclave steaming; 2D model; processing medium temperature; energy consumption; heat balance; loading level of autoclave; moisture content of prisms.

Abstract. A methodology for computation of the processing medium temperature and connected with it energy consumption and heat fluxes during autoclave steaming of non-frozen ooden prisms for veneer production at limited heat power of the steam generator, depending on the dimensions of the prisms cross section, wood moisture content, and loading level of the autoclave has been suggested.
The methodology is based on the use of two personal mathematical models: 2D non-linear model of the temperature distribution in subjected to steaming non-frozen prismatic wood materials and model of the non-stationary heat balance of autoclaves for steaming wood materials. The heat balance of the autoclaves consist of following components: energy used for heating of the subjected to teaming wood materials, energy used for heating of the body of the autoclave and of the situated in it metal trolleys for positioning of the wood materials, energy used for heating of the insulating layer of the autoclave, energy used for covering of the heat emission from the autoclave in the surrounding air, energy used for filling in with steam the free (unoccupied by wood materials) part of the working volume of the autoclave and energy, which is accumulated in the gathered in the lower part of the autoclave condense water. For numerical solving of the models and practical application of the suggested methodology, a software package was prepared in the calculation environment of Visual FORTRAN Professional developed by Microsoft. Using this package computations and research of the non-stationary change of the processing medium temperature in an autoclave with a diameter of 2.4 m, length of its cylindrical part of 9.0 m and loading level of 40, 50, and 60% at a limited heat power of the steam generator, equal to 500 kW during the initial part of the steaming process in it of beech prisms with cross-section dimensions of 0.3 × 0.3 m, 0.4 × 0.4 m, and 0.5 × 0.5 m, initial temperature of 0 °C, basic density of 560 kg·m-3, moisture content of 0.4, 0.6, and 0.8 kg·kg-1 have been carried out. Simultaneously with this the heat fluxes and energy consumption required for the heating of the prisms and for the whole steaming process in the autoclave have been calculated. The suggested methodology can be used for the computation and model based automatic realization of energy efficient optimized regimes for autoclave steaming of different wood materials

Повече

Кey Words: Reconstruction; sequencing; genetic algorithms.

Abstract. Sequences reconstruction is a problem often met in many research areas. The core of this problem is how to recreate a full sequence of ordered information when only chunks of it are known.
Sequence reconstruction is applied in fields like genetics, cryptography and encoding. In this research, an approximate reconstruction of sequences is proposed, which is applied in the gambling industry for reverse engineering of slot machine virtual reels. The importance of this problem is related to the control of gambling games parameters by law regulators. The problem in this research has a combinatorial nature. The analyzed sequences are taken from commercial slot machine games. When the gambler spins the virtual reels he/she does not know how symbols are distributed on the reels. The gambler sees only small parts of the reels when they are stopped. By observing the game for a long enough time the gambler can record these small parts of the reels observer on the screen.
Collecting enough information the gambler can try to reconstruct all positions of the symbols on the virtual reels. Such reconstruction is not trivial, because there is too much unknown information. If there are absolutely identical repeating patterns on the virtual reels the gambler can not find this out by just observing small chunks.
Reverse engineering is commonly used during the analysis of slot machine gambling games. There are many approaches such reverse reconstruction to be done. In most cases, the goal of the engineers is to reconstruct the virtual reels completely. The reconstruction is similar to puzzle solving by attaching each observed piece with a proper corresponding one. Such reconstruction is not always possible because in some cases there is more than one way of connecting the observed pieces. The contribution of this study is related to the approximate reconstruction of the sequences. It does not give a direct solution to the reconstruction problem. Instead of this, it gives an approximate solution. The goal is a little bit changed from the exact reconstruction of the virtual reels to the construction of such reels which will give close behavior of the slot machine gambling game if they are loaded inside the machine instead of the original reels. The innovative approach is that the search for a sub-optimal solution is done in the space of the chunks instead of in the space of the sequences. The proposed approximate reconstruction is approved by experiments with real industrial data.

Повече

Кey Words: Kinvey; JavaScript; jQuery; HTML; CSS.

Abstract. The proposed application discussed in the present article is a browser based strategy game. The programmable languages and tools used for its development including JavaScript, jQuery, HTML, CSS, Kinvey, Sublime Text, etc. The application is build using the 3-Tier Software Architecture. Some of the benefits of this architecture are scalability, speed of development, performance, availability, etc.

Повече

Кey Words: Neural classifiers; state of river waters; Struma river; presence of inadmissible pollution.

Abstract. The aim of the present work is to study the possibilities for developing a system for monitoring the state of the water on the Struma River and the presence of unacceptable pollution. The development of the algorithms of the monitoring system is in accordance with the normative documents of the Republic of Bulgaria and is built on the basis of monitoring measurements for the quality of the river waters from six monitoring points for the period 2010-2019. The following variables characterizing water quality were analyzed:
ammonium nitrogen (NH4-N), nitrate nitrogen (NO3-N), nitrite nitrogen (NO2-N), pH, biological oxygen demand (BOD), electrical conductivity (EC), total nitrogen (TN), total organic carbon (TOC), total phosphorus (TP), orthophosphate phosphorus (PO4-P), dissolved oxygen (DO), temperature (T) and chemical oxygen demand (COD).
The section of the river Struma from before Blagoevgrad to the border (bridge for the village of Topolnitsa) was chosen for the research. The available measurement data from six monitoring points in the considered section of the Struma River are as synchronized as possible.
Correlation analyzes were performed for the possibility of combining the available measurements from the six monitoring points and for the presence of a correlation dependence between the measured variables characterizing the water quality in the Struma River. The presence of correlations between the variables directs the use of the principal components method as a mathematical apparatus for building the monitoring system. Procedures have been developed for classifying the status of river waters depending on current measurements / analyzes. Expressions for the main components for eleven of the measured variables characterizing water quality are derived.
Research has been carried out to develop a procedure for classifying these measurements into the terms „excellent“, „good“ and „moderate“.
Possibilities for classifications with neural networks have been studied. Measuring some of these variables is a lengthy procedure and can hardly be used for operational actions. For this reason, the possibilities for developing a procedure for monitoring and classifying the status of river waters on the basis of variables, which in principle can be measured automatically (pH, EC, DO and T), have been explored. They also apply the principal components method and classification with neural networks in the same classification categories.
The developed approaches for monitoring the quality of the waters of the Struma River can be applied for each measurement in the six monitored monitoring points.

Повече

Кey Words: NIR spectroscopy; chemometric methods; environmental analysis; contaminated soils.

Abstract. Conducting quantitative analysis of soil properties and contaminants in them is a crucial for an achievement of a good understanding of dynamics of ecosystems and a sustainable soil management.
This study presents the recent progress on the developed combined approaches including NIR spectroscopy and chemometrics for accurate, low-cost and reliable quantitative analysis of soil content, published in prestigious journals for the last 7 years. A classification of the approaches depending on the types of soils components, the type of applied pre-processing and chemometric methods
is done. Their main advantages and disadvantages are shown and some trends for future development are outlined.

Повече