Wyniki wyszukiwania - Biblioteka Nauki

1

Comparison of genetic algorithm and neural network approaches for the prognosis of mechanical idle running losses in agriculture tractor transmission

100%

Ivanov R. , Ivanova D.

Transport Problems

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2022

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tom T. 17, z. 3

51--59

EN

An experimental investigation of mechanical idle running losses in an agriculture tractor transmission was used to collect a wide range of data. The influence of the engine rotation speed, the number of switched-on gears, and the oil level in the transmission gearbox on the idle running losses was determined. Adequate regression models in cases of switched-on and switched-off PTO were received. A genetic algorithm was used to optimize mathematical models obtained using regression analysis. A feedforward artificial neural network was also developed to estimate the same experimental data for mechanical idle running losses in transmission. A back-propagation algorithm was used when training and testing the network. A comparison of the correlation coefficient, reduced chi-square, mean bias error, and root mean square error between the experimental data and fit values of the obtained models was made. It was concluded that the neural network represented the mechanical idle running losses in tractor transmission more accurately than other models.

2

Treatment of Acid Mine Drainage in a Bioelectrochemical System, Based on an Anodic Microbial Sulfate Reduction

80%

Angelov A. , Bratkova S. , Ivanov R. , Velichkova P.

Journal of Ecological Engineering

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2023

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tom Vol. 24, nr 7

175--186

EN

The possibilities of simultaneous removal of sulfates and heavy metals (Cu, Ni, Zn) from acid mine drainage have been investigated in two-section bioelectrochemical system (BES). The used BES is based on the microbial sulfate reduction (MSR) process in the anode zone and abiotic reduction processes in the cathodic zone. In the present study, the model acid mine drainage with high sulfate (around 4.5 g/l) and heavy metals (Cu2+, Ni2+ and Zn2+) content was performed. As a separator in the laboratory, BES used an anionic exchange membrane (AEM), and for electron donor in the process of microbial sulfate reduction in the bioanode zone – waste ethanol stillage from the distillery industry was employed. In this study, the possibility of sulfates removal from the cathodic zone was established by their forced migration through AEM to the anode zone. Simultaneously, as a result of the MSR process, the sulfate ions passed through AEM are reduced to H2S in the anode zone. The produced H2S, having its role as a mediator in electron transfer, is oxidized on the anode surface to S0 and other forms of sulfur. The applicability of waste ethanol stillage as a cheap and affordable organic substrate for the MSR process has also been established. Heavy metals (Cu2+, Ni2+ and Zn2+) occur in the cathode chamber of BES in different degrees of the removal. As a microbial fuel cell (MFC) operating for 120 hours, the reduction rate of Cu2+ reaches 94.6% (in waste ethanol stillage) and 98.6% (in the case of Postgate culture medium). On the other hand, in terms of Ni2+ and Zn2+, no significant decrease in their concentrations in the liquid phase is found. In the case of microbial electrolysis cell (MEC) mode reduction of Cu2+– 99.9%, Ni2+– 65.9% and Zn2+– 64.0% was achieved. For 96 hours, the removal of sulfates in MEC mode reached 69.9% in comparison with MFC mode – 35.2%.

3

Octave band analysis of car noise emissions at different speeds and on different pavements

80%

Staneva G. , Ivanov R. , Kadikyanov G.

Transport Problems

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2023

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tom T. 18, z. 2

63--73

EN

Noise from cars is one of the main sources of harmful pollution. In the presented paper, an octave frequency band analysis is conducted according to standard methods of external and internal noise measurement. Experiments at different speeds, with three types of cars - conventional gasoline (GV), hybrid (HEV) and pure electric (BEV) - were carried out on two types of pavement - damaged coarse-grained and smooth fine-grained asphalt. The results show variations in external and internal noise levels vs. speed in different octave bands. At each speed, a spectral analysis was done. The diagrams with results show changes in noise level vs. speed and the positions of noise maximums. Regression models for the octave spectrum at different speeds and pavements are developed.

4

Life cycle energy consumption and CO2 emissions of different car types

80%

Ivanov R. , Evtimov I. , Kirilov K. , Minkovska I.

Transport Problems

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2023

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tom T. 18, z. 3

101--111

EN

In this research, the energy consumption and emissions of gasoline cars, battery electric cars, fuel cells electric (FCE) cars, compressed naturel gas (CNG) cars, liquid propane-butane gas (LPG) cars, etc., during their life cycles are presented. A set of flow charts presenting the production of cars and used fuel/energy is developed. These charts and the latest data for electricity production emission factor and raw materials prices are used. A comparative analysis is done. Results for primary energy and carbon emissions are presented in graphical form. They show the most economical and ecological car decisions.

5

A study of the fuel consumption of hybrid car Toyota Yaris

70%

Ivanov Y. , Ivanov R. , Kadikyanov G. , Staneva G. , Danilov I.

Transport Problems

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2019

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tom T. 14, z. 1

155--167

EN

The paper presents the experimental results from a complex study of the fuel consumption of a hybrid car Toyota Yaris. Original data for motion at different constant speeds are obtained. The economical and energy characteristics of the car are observed and analyzed. Three typical urban and three inter-city routes are investigated. A significant decrease in the fuel consumption of the hybrid car is witnessed when it runs in urban conditions at “Eco Mode”. The motion on inter-city route, including short town passages and highway parts, is also investigated. The obtained original data are higher than the fuel consumption given by the producer and, practically, equal to the ones of the conventional gasoline car. The study indicates that the effect of a hybrid system is significant in urban conditions and is more evident at “Eco Mode”.

6

Life cycle assessment of fuel cells electric vehicles

70%

Evtimov I. , Ivanov R. , Stanchev H. , Kadikyanov G. , Staneva G.

Transport Problems

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2020

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tom T. 15, z. 3

153--166

EN

In recent years, regarding the influence of the production processes and vehicles on the environment, new technical solutions for reducing air pollutions have been studied and developed. One of the new constructions is fuel cell electric vehicle (FCEV). The production and running conditions of the vehicles are specific in different countries. Hence, a study of these conditions and fuel production process is needed. In this paper, a study of the FCEV efficiency, at different producing technologies of hydrogen (H2), is carried out. Life cycle assessment (LCA) method is used. A comparison, concerning fuel consumption and emissions as CO2 equivalent for the whole life cycle, is done for FCEV and conventional gasoline vehicle (GV). The influence of the energy mix and technology of production of hydrogen on spent energy and air pollution is analyzed. As the results show, in countries with CO2 emissions over 447 g per 1 kWh electricity, the technology of hydrogen production from natural gas is most effective. Now and in the near future, the ecological and financial advantages, connected to renovation of existing vehicle fleet with FCEV, are not absolutely verified.