Selection Of Optimal Solution Research Articles

Economic and mathematical approach to optimization of vacuum-freeze drying of the enzyme preparation inulinase Bacillus polymyxa 29

One of the promising directions of improving the processes of processing plant raw materials is bioconversion using enzyme preparations, the use of which allows you to significantly change, intensify and improve existing technologies for the production of food products as a system of energy-efficient processes. The subject of the study is the enzyme preparation of inulinase Bacillus polymyxa 29, which ensures the conversion of the plant polymer inulin to fructose. Fructose has an increased interest in food technologies as a safer human health alternative to sucrose. Fructose yield reaches 90–95%; the sweetness coefficient of fructose is 1.73 times higher than sucrose. Production of enzyme with maximum activity is achieved by vacuum-sublimation drying at time-programmed mode of heat supply control taking into account limitations due to quality of heat exchange and economic feasibility of the process. Method of selection of optimal solutions in vacuum-sublimation drying of feather preparation Bacillus polymyxa 29 according to profit index is proposed. The proposed approach resolved the main technical gap between productivity and energy consumption. An optimal loading of the sublimator has been established, which ensures the minimization of specific electric power consumption for various values of the initial moisture drying of the enzyme, taking into account the given efficiency of the vacuum sublimation dryer.

Decision-making model for optimum energy retrofitting strategies in residential buildings

Existing buildings consume an inordinate amount of energy globally. The consumption negatively affects the environment and economy; therefore, it is necessary to improve energy performance in buildings by retrofitting the existing ones. Several energy retrofitting strategies are proposed in the energy efficiency programs, and hence, the selection of optimal and efficient solutions is a complex task. Several factors affect the implementation of energy retrofitting measures such as budget, comfort requirement, and reliable economic value. To this end, the study was conducted to develop a decision-support model for residential building owners based on Mixed Integer Linear Programming. The model was designed to select optimum energy retrofitting strategies. The objective function involves minimizing the total Life Cycle Cost of the energy retrofitting plan to achieve economic benefit while considering the budget, thermal comfort, and recommended illumination level as primary constraints. To test the validity of the model, a case study of a residential building was conducted. The findings of the study suggest an energy retrofitting plan that decreases approximately 70% of energy consumption. A sensitivity analysis was conducted to examine the effect of the change in the cost component on the Life Cycle Cost and energy saving.

PREIDENTIFICATION OF ADAPTIVE MECHANISMS OF BIOSPHERE-COMPATIBLE CONSTRUCTION TECHNOLOGIES

The article discusses the main stages in the selection of optimal production technologies that are adapted to environmental and economic constraints in accordance with international regulatory acts on the state of the environment. The boundaries of the selection of optimal solutions and the algorithm for the stages of their assessment based on sustainable development taking into account environmental, economic and social imperatives are presented. On the example of the construction industry, the ways of transition to a new concept of economic development are proposed, in which the priority objectives of the extraction and processing of natural resources are provided by movement in the direction of a "circular" economy with cascading use and minimization of residual products.It also analyzed and proposed promising areas for the use of IT tools and biosphere-compatible technologies to ensure sustainable development.Key words: greening the economy, environmental audit, secondary raw materials, recycling, biosphere-compatible technologies.

Electronic classifier of natural water treatment technologies

The choice of methods of water treatment in conditions of increasing requirements for drinking water quality, lack of funding for the commissioning of new water supply capacities and non-decreasing anthropogenic loads on water sources, is dominant in the design of new and reconstruction of existing water treatment stations. The authors developed an electronic classifier of natural water treatment technologies for computer support of selection and feasibility study of optimal design solution of water supply on the basis of classifiers of technological schemes of water treatment, developed by the team of authors under scientific and methodological guidance of M.G. Jurba. Use of this system allows to increase efficiency of design of new water treatment stations and reconstruction of existing ones due to reduction of selection time of technological schemes, to minimize probability of selection error. It provides the best value for money for the project.

Thermoeconomic analysis of a CO2 plume geothermal and supercritical CO2 Brayton combined cycle using solar energy as auxiliary heat source

Abstract: This study presents an investigation of a CO2 plume geothermal and supercritical CO2 Brayton (CPG-sCO2) combined cycle using solar energy as auxiliary heat source. This combined cycle may help solve the problems of CO2 sequestration and geothermal energy utilization simultaneously. The CPG production is heated by a solar power generation system with solar tower and molten salt. Then a recompression sCO2 cycle utilizes geothermal energy and solar energy directly. A solution procedure is performed to analyze the thermoeconomic performance of the CPG-sCO2 combined cycle. Results show that the combined cycle has an optimal main compressor inlet pressure and split ratio for maximum combined cycle efficiency. It can achieve 19.57% by genetic algorithm (GA) optimization, which is 5.65% and 4.07% higher than CPG systems with indirect sCO2 cycle and organic Rankine cycle, respectively. Moreover, it indicates that the combined cycle efficiency and total capital cost have opposite variation trends with the increase of parameters, including main compressor inlet pressure (p5), split ratio (sr), well distance (d8,11) and injection temperature (T8). Based on multi-objective GA optimization and optimal solution selection, it is concluded that the most thermoeconomic CPG-sCO2 combined cycle has a combined cycle efficiency of 18.09% and a total capital cost of $5.959 × 107, respectively. Findings suggest that the CPG-sCO2 combined cycle has potential to combine CO2 sequestration with geothermal energy utilization.

Enhancing the efficiency of gas-oil (oil-gas) deposits development based on selection of optimal engineering solutions for Perm Region fields

Enhancing the efficiency of gas-oil (oil-gas) deposits development based on selection of optimal engineering solutions for Perm Region fields

СТРОИТЕЛЬНАЯ СИСТЕМА ВОЗВЕДЕНИЯ ПОЛНОСБОРНЫХ ЗДАНИЙ ИЗ ГОТОВЫХ МОДУЛЕЙ

Introduction : The article presents a study and justification of the concept for the erection of prefabricated buildings out of modules on a pre-arranged foundation with a comprehensive assessment of quality, accuracy, constructability and safety of building superstructure blocks. Purpose of the study: Development of rapid construction is driven by the need for affordable housing in Russian towns and cities, the need for the erection of buildings of various purposes within short time frames in regions with severe and extreme climate. Methods: Prefabricated construction is a promising industry, but it is required to perform studies on the selection of optimal organizational and technological solutions, aligning those with modern standards and requirements. Results: The authors consider a method of choosing a technique for the construction of pile foundations for multi-purpose prefabricated buildings with account for the analysis of existing loads and structural features. Determination of constructability criteria makes it possible to assess the comparative efficiency of the prefabricated-construction techniques with account for data of geotechnical surveys, conditions of a construction site, etc.

Environmentally Friendly Rock Mining—Case Study of the Limestone Mine “Górażdże”, Poland

Mining activities affect the environment, while proper reclamation and management of areas transformed by these activities can bring about new, and often much better changes in the landscape. This paper presents the project of the reclamation of the limestone mine “Górażdże” and attempts to extend the directions of reclamation of degraded areas left after extracting activities. The aim of this extension is to present reclamation, which can be an environmentally friendly proposal and therefore positively received by the local community. It was proposed to successively enrich the forest and aquatic reclamation directions by adding a natural one. The selection of optimal solutions was based on rational and the most appropriate criteria, such as taking into account, first of all, the existing natural properties in the area of the quarry under analysis and also the possibility of their future protection. On the other hand, due to the social and economic aspects supported by the natural potential, it was proposed to introduce a recreational and tourist direction, which will not interfere with the current forestry and proposed natural development direction. Finally, after the cessation of mining activity in the mining area, it is suggested to create a geopark and to activate geotourism. The proposed solution may significantly affect the social and economic development, while at the same time maintain the valuable natural environment.

Management of a transport and logistics terminal: models, indicators and optimization

The management toolkit of the transport and logistics terminal in the form of a three-tier management model is presented. It ensures the development of strategies for its operation, using the distribution of flows across various types of transport. A set of indicators for the efficient functioning of TLT was determined. Ten strategies for the operation of the transport and logistics terminal with a combined rail and road transport in the distribution of general cargo flows were considered. A decisions ranking for a given range of costs was implemented. A full normalization of indicators and the selection of optimal solutions for the flows distribution in a flexible manner were performed. The selection of solutions was carried out by the Pareto-optimization method.

Optimizing the landslide-prone slope stabilization

Introduction. Nowadays, the study of landslide processes is one of the most intensive aspects of construction and maintenance of industrial and civil buildings and installations. The landslides violate the stability of foundations and entire complexes of installations, so the assessment of the stability of the slopes is the most important task before starting the construction. Currently, there is a large number of landslide classifications, which characterize the conditions of their formation, the history of geological development, their age, and structure. Normative documentation gives three ways of slope slump control: preventive, restricting, and liquidation ones. However, this source does not give systematic validity of the engineering solutions. The study sets the following tasks: to develop an algorithm for the optimal choice of rational slope strengthening in landslide construction conditions and to test it with a specific example.
 Materials and methods. The study analyzed the publications on theoretical and practical experience in dealing with landslides as well as normative documents. Numerical simulation methods were used to calculate the slope stability when testing the algorithm.
 Results. Using the introduced classification, the study presented an algorithm that makes it possible to choose a rational way of slope strengthening under landslide construction conditions. The concept of the algorithm allows step-by-step approximating parameters of a landslide-prone slope model to the real conditions, on the one hand, and selecting the most reasonable anti-landslide measures, on the other hand. The developed algorithm was tested on the territory of a large industrial complex situated on river overflood plain fringes. By applying the value engineering comparison of several slope stabilization variants, the research has taken the most optimal one of them for realization.
 Conclusions. The study developed the author’s classification and algorithm for the selection of optimal design solutions to stabilize landslide-prone slopes or slants. Successful approbation of the algorithm confirmed its practical applicability. The algorithm allows choosing the most effective complex for protection against landslides.

Towards optimal trade-offs between material and energy recovery for green waste

Green waste is a type of biomass consisting mainly of grass, leaves and fresh prunings originating from gardens and parks. It can be used as feedstock for composting, or for energy recovery. The EU Waste Directive 2008/98/EC advocates composting to prevent waste. This directive allows green waste to be used for (renewable) energy valorization only if a better overall environmental outcome can be demonstrated. In this paper, we propose an assessment procedure based on examining the Pareto front of optimal trade-off combinations for maximizing composting and energy recovery of green waste while minimizing environmental impact and minimizing particulate matter emission. The Pareto optimal front is determined by solving a multi-objective optimization problem using the ε-constraint method. Previous research on green waste valorization using Life Cycle Analysis (LCA) shows that either energy recovery or composting is the preferred option depending on how environmental impact is assessed. In contrast to the full assignment to one of these recovery methods produced by LCA, we demonstrate, using the case of green waste valorization in the Netherlands and Belgium, that the proposed assessment procedure provides optimal solutions in a range between full allocation to compost or energy recovery. The proposed methodology supports the selection of optimal solutions taking the decision makers’ preference into account that allows complying with Directives that have opposite goals on green waste valorization. Finally, computational results show that the assessment of the “better environmental outcome” requested by the EU waste Directive 2008/98/EC is influenced by the life cycle impact categories and the policy makers preferences with respect to the valorization options taken into account. Since the EU waste Directive 2008/98/EC does not specify how to execute the outcome assessment of valorization alternatives, this can lead to ambiguity.

Modelling of FPGA-Particle Swarm Optimized GNSS Receiver for Satellite Applications

The purpose of this paper is to design a low power Global Navigation Satellite System receiver for satellite application based on Particle Swarm Optimization (PSO) algorithm. The receiver processes the satellites signals and provide enough information for wide range of applications. Most of the applications relies on the navigation solution such as position, velocity and time. The receiver continuously acquire and track the signals from the satellites in order to compute the continuous solution based on the requirement of application. The navigation solution based on the computation distance between the receiver and set of satellites. The proposed method uses the PSO based navigation process. Hence it provide better performance through the selection of optimal solution (position, velocity and time). The proposed work is implemented in Xilinx platform and compared with various target devices in terms of frequency and area. The comparative analysis clearly demonstrate the better performance of proposed work under various target devices.

Manufacturing uncertainties and resulting robustness of optimized patch positions on continuous-discontinuous fiber reinforced polymer structures

Discontinuous fiber-reinforced Sheet Moulding Compound (SMC) in combination with continuous carbon fiber patches provide a high design freedom in combination with good weight-specific properties. However, the application of these materials requires a strategic and exact positioning of the patches, necessitating the consideration of unavoidable manufacturing defects during the design phase. Therefore, a workflow is proposed to evaluate the robustness of multi-objective patch optimization results using two robustness measures, the degree of robustness and robustness index. An efficient calculation of the robustness measures is achieved by replacing computational expensive simulation models with a Kriging surrogate model. Typical manufacturing deviations occurring during the patch positioning and moulding process are determined from experiments using active thermography. Finally, the proposed workflow is applied to the multi-objective optimization of two patches on a demonstrator under four-point-bending load. The resulting robustness measures can be used as a decision criterion for the selection of the best Pareto optimal solution. Furthermore, they can be used for the determination of the maximum occurring objective variation as well as the largest permissible manufacturing tolerances.

МЕТОДИЧЕСКАЯ БАЗА ВЫБОРА И ОБОСНОВАНИЯ ОПТИМАЛЬНЫХ ПРОЕКТНЫХ РЕШЕНИЙ ГОРНОДОБЫВАЮЩИХ ПРЕДПРИЯТИЙ

МЕТОДИЧЕСКАЯ БАЗА ВЫБОРА И ОБОСНОВАНИЯ ОПТИМАЛЬНЫХ ПРОЕКТНЫХ РЕШЕНИЙ ГОРНОДОБЫВАЮЩИХ ПРЕДПРИЯТИЙ

Preduzetničko obrazovanje u funkciji razvoja veština za četvrtu industrijsku revoluciju

New technologies are leading to changes in business models. Skills needed to perform most jobs are changing profoundly. Their acquisition and development are becoming crucial for the success and modernization of the labour market offering new forms of flexibility and security for job seekers, employees and employers. The era of automation necessitates the development of not only digital, but also social and emotional skills. Development of creativity, innovation, analytical and critical thinking, communication, negotiation and decision-making skills are gaining in importance. These skills, an integral part of entrepreneurship competence, are developed through entrepreneurship education. In today's world, this form of education is approached not only in the narrow sense, as a process of preparing for business creation, but also in a wider context, as a process of developing entrepreneurial mindset and skills and personal qualities that have universal application. There are several approaches, methods and models of entrepreneurship education. Serbia does not yet have a clearly defined strategy for developing this type of education. Aimed at providing recommendations for the selection of optimal solutions, an assessment study of the effects of the 'Student Company' method of entrepreneurship education, recognized globally as a model of good practice, was carried out within our education system. The research has shown that, according to the assessment of 175 teachers involved in the programme, the 'Student Company' method also gives excellent results in our country. This speaks in favour of its inclusion in all secondary schools in Serbia as an informal type of education.

To the question of optimal design of worm-cylindrical gearboxes

The problem of multicriteria optimal design of a worm-cylinder reducer with a lower location of the Archimedean worm is considered. A designmathematical model of a reducer has been developed, with the use of which, using the example of parametric optimization of a specific gearbox, effective optimization parameters have been determined and the problem of the optimal distribution of the overall gear ratio between its stages has been investigated. To solve this problem, we used the method of admissible sets based on the PSI design ideology. The results of numerical analysis of the information space of the reducer under study, in particular, the analysis of the influence of the number of gear teeth and material for the production of cylindrical wheels are given. To provide a crankcase lubrication system for gears and reduce the height of the type of reducers in question, an algorithm is proposed for calculating the cylindrical gear. The existing recommendations on the distribution of gear ratios over the reducer stages are analyzed and recommendations for the selection of optimal rational design solutions for the reducer under consideration are given, with different limitations on the quality criteria. Conclusions are drawn from the results of the studies. The developed software implementation of the proposed design methodology can be used as a tool for optimally-rational design of stepped gear reducers.

Thermal Deformation of Window for Climatic Conditions of Russia

During the last decades in Russia new designs of window found wide application. As a rule, modern designs of window are made of combinations of materials with different thermal characteristics. Most of them are designed for European climatic conditions. Operation in climatic conditions of Russia can lead to essential thermal deformations of elements of a design of window. It is necessary to consider that thermal deformations of various elements of window (a frame, a shutter, an impost) can lead to change of the main operational parameters of a design. Current regulations this parameter is not currently normalized. The authors conducted a large volume of experimental studies of window blocks made of PVC, aluminum alloys and other materials in order to assess the impact of thermal deformation on the characteristics of window blocks. On the basis of the conducted studies revealed a significant influence of thermal deformation of structures on thermal performance, the minimum temperature on the inner surface, the change of air permeability through the window unit, reducing the insulation of window units. Thus, the revealed physical process directly influences maintenance of comfort, an internal microclimate, costs of heating, ventilation and conditioning of buildings. Taking into account the diversity of climatic regions of Russia, there is a need for a comprehensive assessment of the main performance characteristics of window units, the development of measures to reduce the impact of thermal deformation on the performance of window units and the selection of optimal technical solutions for a given region of construction.

Analytical-stochastic availability model of multi-functional cloud infrastructure

Purpose. Analyze stochastic methods for metamodeling of cloud infrastructures (СI) based on conceptual requirements for ensuring their readiness taking into account performance requirements, scalability of the computing resource, energy saving and elasticity of control of the components of the СI. The technique. The analysis of stochastic methods used to model the behavior and assess readiness indicators, the reliability of cloud infrastructures (СI) is performed. As a fundamental basis, the taxonomy of OO metamodeling is considered, which is based on the conceptual foundations of ensuring productivity, resource scalability, energy saving, and elasticity of management of the components of the cloud infrastructure. In addition to the well-known estimation methods using the apparatus of stochastic Petri nets, Markov chains are proposed to focus on the possibility of using semi-Markov modeling methods that contribute to improving the accuracy of evaluating the metrics of the quality of services provided (QoS). Results. The proposed taxonomy is a fundamental basis for modeling behavior and assessing the availability and reliability of cloud infrastructures. Scientific novelty. The problem of the lack of methodology for modeling the processes of СI functioning is solved, which is based on a single taxonomic basis of a comprehensive solution to the problem of assessing, analyzing and monitoring the level of readiness of cloud infrastructures. Practical value. The analysis opens up the possibility of using stochastic methods to ensure performance, resource scalability, energy saving and elasticity of management of the components of the cloud infrastructure. The considered methods of modeling can be applied to the selection of optimal architectural solutions in accordance with the established criterion of readiness of cloud infrastructures.

Multiobjective process optimization for betaine enriched spelt flour based extrudates

AbstractThe main purposes of this work are successful modeling of twin‐screw extrusion process using predictive models, investigating the effect of process parameters such as screw speed, feed rate, and feed moisture content on the process and product responses and finally optimizing the process regarding betaine content in the extruded product and energy consumption. The second order polynomial approximation models and the artificial neural network were developed to predict the betaine content, showing the high accuracy in the prediction of experimental results. This study introduces the multiobjective optimization (MOO) approach in the extrusion process of spelt flour. The maximal betaine content (between 1,506.8 and 1,605.2 mg/40 g) and minimal energy consumption (between 101.3 and 108.5 W hr/kg) were indicated by MOO procedure, which were gained using the following input parameters: feed flow rate feed about 24 kg/h, screw speed about 252 RPM and moisture content from 21.6 to 23.4%.Practical applicationsThis study introduces the multiobjective optimization (MOO) approach in the extrusion process of spelt flour, which provides the selection of optimal solution that enables the extruder to reach the optimum conditions of the process and provide decision maker with deeper understanding of the process. The present study analyzes the influence of extrusion cooking parameters like: screw speed, feed flow rate, and feed moisture content on the betaine content in the extrudate product and specific mechanical energy input during the processing of betaine enriched spelt flour based extrudates. One way to improve the intake of betaine in the general population can be to enrich foods with betaine. According to European Breakfast Cereal Association for extruded products portion sizes should be 40 g. Consuming a portion of a functional extrudate product with the addition of betaine (1,500 mg/day) could give expected health effects. Final extrudate product from this study satisfies these statements.

TECHNICAL SOLUTIONS FOR DECREASING NOX EMISSIONS AT COAL THERMAL ELECTRIC POWER STATIONS

Most power-generating units at the Ukrainian thermal electric power stations were designed to burn hard coal mined in Ukraine, but today due to physical depreciation of the stations, those units are in non-project manoeuvring peaking operation what leads to the increase in both the specific fuel equivalent consumption and in harmful environmental emissions. The purpose of the research is to develop recommendations on the selection of optimal technical solutions aimed at reducing NOx emissions of oxides at the operating boilers of Burshtyn thermal electric power stations (TEPS) under the conditions of regime-technological measures. The article analyzes the main approaches to developing and selecting technological methods aimed at reducing emissions of coal thermal power stations and identifies prospects for their work in accordance with modern environmental requirements. The mechanisms of the transformations the organic fuel bound nitrogen undergoes when heated are determined. To reduce the amount of NOx emissions in combustion products, it is offered to apply the regime-technological mode of the preliminary heating the pulverized coal mixture. The results of thermo chemical studies of coal samples used at Burshtyn TEPS are presented. The temperature ranges are determined at which the maximum emissions of volatile combustible compounds takes place before to the upper flammability limit of the pulverized coal mixture is reached. It was determined that under the conditions of actual burning process, there is a clear sequence: a release of volatile components and burning of the coke residue; heating of the pulverized coal mixture; emission of volatile combustible compounds; their burning; heating of the coke residue up to initiation of its combustion; the coke residue burning-out. A pulverized coal stream is brought into the furnace without being preliminary mixed up with air. While burning the pulverized coal stream, fuel particles are heated and degassed in the zone immediately adjacent to the burner section where there is a shortage of oxygen, whereas the oxygen concentration in the flow is a gradually increasing. The regime-technological measures that are aimed at inhibiting NOx oxides formation by preliminary heat treatment of the pulverized coal mixture; they make it possible to obtain the maximum emissions of volatile combustible compounds before the upper flammability limit of the pulverized coal mixture is reached. It was found out that heat treatment should be carried out at temperature from 540-580° C. This is the temperatures range when the maximum emission of volatile combustible compounds takes place. After this combustion occur in an environment that is practically devoid of oxygen, where competing reactions of formation of volatile components and molecular nitrogen occur simultaneously. Thereafter, combustion can proceed in the practically oxygen-free environment with competing parallel reactions the forming volatile components and molecular nitrogen. This method allows to almost halving the concentration of nitrogen oxides in flue gases.