Volume 16 (2018)
  Special Issue 1

Full text of the journal: Volume 16 Special Issue 1

Contents


Pages

943-951 A. Avotins, P. Apse-Apsitis, J. Bicāns and J. Gruduls
Development and testing results of IoT based air temperature and humidity measurement system for industrial greenhouse
Abstract |
Full text PDF (932 kB)

Development and testing results of IoT based air temperature and humidity measurement system for industrial greenhouse

A. Avotins¹*, P. Apse-Apsitis¹, J. Bicāns¹ and J. Gruduls²

¹Riga Technical University, Institute of Industrial Electronics and Electrical Engineering, Azenes 12, LV-1048 Riga, Latvia
²SIA “Latgales darzenu logistika” greenhouse, “Kloneshniki”, Mezvidi parish, LV-5725 Karsava region, Latvia
*Correspondence: ansis.avotins@rtu.lv

Abstract:

Industrial greenhouse control systems are changing and getting new capabilities, due to the evolution of the Internet of Things (IoT) technologies, allowing wirelessly integrate various sensor technologies and create a cloud-based database and analytic solutions. Greenhouse systems typically are controlled by consuming single temperature and humidity measurement unit data (treated as an average value), this raises a question about the precision of such approach for application in a large industrial greenhouse. In this article IoT based temperature and humidity measurement system uMOL architecture is described and first measurement results of multi-point data collection with high resolution compared to existing single-point measurements.

Key words:

, , , ,




952-957 A. Avotins, A. Potapovs, P. Apse-Apsitis and J. Gruduls
Crop weight measurement sensor for IoT based industrial greenhouse systems
Abstract |

Crop weight measurement sensor for IoT based industrial greenhouse systems

A. Avotins¹*, A. Potapovs¹, P. Apse-Apsitis¹ and J. Gruduls²

¹Riga Technical University, Institute of Industrial Electronics and Electrical Engineering, Azenes 12, LV-1048 Riga, Latvia
²SIA ‘Latgales darzenu logistika’ greenhouse, “Kloneshniki”, Mezvidi parish, LV-5725 Karsava region, Latvia
*Correspondence: ansis.avotins@rtu.lv

Abstract:

Nowadays the industrial management systems are changing by means of implementing various Internet of Things (IoT) technologies, allowing a simple integration of sensor technologies with wireless communications and development of cloud based database solutions. The industrial greenhouse management systems are not the exception in this regard, as they are becoming more and more popular with the use of various sensors for the automation of the vegetable and other crop cultivation process.The general aim they have is to raise the level of process automation, quality, energy efficiency and other important parameters. The implemented technologies and environment of industrial greenhouse can be different fir the research type laboratories, as they are focused on production, therefore this research is conducted in cooperation with tomato producing industrial greenhouse of SIA ‘Latgales darzenu logistika’ focusing on IoT based crop weight measurement.

Key words:

, , ,




958-967 D. Berjoza, V. Pīrs and I. Jurgena
Investigation into the performance characteristics of electric automobiles by means of a data logger
Abstract |

Investigation into the performance characteristics of electric automobiles by means of a data logger

D. Berjoza¹*, V. Pīrs¹ and I. Jurgena²*

¹Latvia University of Life Sciences and Technologies, Technical Faculty, Institute of Motor Vehicles, 5 J. Cakstes boulevard, LV-3001 Jelgava, Latvia
²University of Life Sciences and Technologies, Faculty of Economics and Social Development, Institute of Business and Management Science, 18 Svetes street LV-3001 Jelgava, Latvia
*Correspondence: dainis.berjoza@llu.lv; inara.jurgena@llu.lv

Abstract:

Fossil fuel deposits are constrained in the world. Various alternative energy sources are introduced in vehicles to limit the depletion of fossil fuel reserves and to reduce environmental pollution. One of the alternative energy sources is electricity. The use of electric automobiles has begun in the Baltic States too, yet accurate performance parameters of the automobiles, which could sometimes differ from the technical characteristics specified, are not always known. Road testing an electric automobile was performed using a data logger that recorded the battery’s voltage, current, temperature and the automobile’s speed. These parameters allowed computing changes in the electric automobile’s power output under various driving regimes, e.g. acceleration or braking. Road testing the electric automobile was done under two driving regimes – urban and non-urban – on a certain route. The experiment represented a full cycle road test, with the batteries fully charged, that lasted until the batteries were discharged to a minimum level, which was limited by the battery management system (BMS). The experiment identified the maximum current as well as the effectiveness of the regenerative braking system.

Key words:

, , , , ,




968-976 A. Birkavs and R. Smigins
Experimental research on compatibility of mineral and biobased hydraulic oils
Abstract |
Full text PDF (735 kB)

Experimental research on compatibility of mineral and biobased hydraulic oils

A. Birkavs* and R. Smigins

Latvia University of Life Sciences and Technologies, Faculty of Engineering, Motor Vehicle Institute, 5 J.Cakstes blvd, LV3001 Jelgava, Latvia
*Correspondence: aivars.birkavs@llu.lv

Abstract:

The use of biobased hydraulic oils becomes more popular in the different industries, but especially in agriculture machinery. This is stimulated by the fact that significant amount of hydraulic oils effluence in the environment and therefore leaves a negative impact to the ecosystem. Besides of that, the part of sold hydraulic oils grows and now forms approximately 15% of total oil consumption amounts worldwide (Nagendramma & Kaul, 2012).
The aim of this research was to study the compatibility of the comercially produced mineral and biobased hydraulic oils, identify viscosity of a different mixtures in the entire work temperature range, as also changes of anti-frictional properties. Two different oils and three mixtures were tested. Special hydraulic experimental apparatus was established for visual observation of fluid properties. Sliding friction bench was used for the comparision of friction properties.
The results showed that change of the working pressure and temperature of the hydraulic oil in the various mixtures of mineral and biological hydraulic oils do not change its original appearance. It was observed that the highest viscosity 71 mm2 s-1 and worst anti-friction properties is for the 50% mix of mineral and biologial hydraulic oil at 20 °C ambient temperature.

Key words:

, , ,




977-984 A. Birkavs and R. Smigins
An assessment of stratification of exhaust gases from gasoline and diesel engine
Abstract |
Full text PDF (797 kB)

An assessment of stratification of exhaust gases from gasoline and diesel engine

A. Birkavs* and R. Smigins

Latvia University of Life Sciences and Technologies, Faculty of Engineering, Motor Vehicle Institute, 5 J.Cakstes blvd, LV3001 Jelgava, Latvia
*Correspondence: aivars.birkavs@llu.lv

Abstract:

Research the aim of which was to find out stratification of main exhaust components outside the tailpipe of the vehicle was realized in Alternative Fuels Research Laboratory of Latvia University of Agriculture using two commercially produced testing vehicles (diesel and gasoline) and exhaust gas analytical system AVL SESAM FTIR. Additionally there was created a gas testing camera allowing to measure concentration of exhaust gas components in different heights and windless conditions. Regulated and unregulated emissions from gasoline and diesel engines were measured and discussed. Results obtained during the measurements showed main stratification of toxic components from both engine types from 0.6 to 1.1 m from the ground making a risk to get some health problems by inhalation, especially for children. Main components (NOx, CO, HC) of exhaust gases of gasoline engines stay in the air for about 15 minutes in height of 1.0 m from the ground level, while methane and acetylene stay in the air for a 15 minutes in height of 0.6 m from the ground level.

Key words:

, , , ,




985-996 J. Čedík, M. Pexa, M. Holůbek, D. Mader and R. Pražan
Effect of sunflower and rapeseed oil on production of solid particles and performance of diesel engine
Abstract |
Full text PDF (735 kB)

Effect of sunflower and rapeseed oil on production of solid particles and performance of diesel engine

J. Čedík¹*, M. Pexa¹, M. Holůbek¹, D. Mader¹ and R. Pražan²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ165 21 Prague 6, Czech Republic
²Research Institute of Agriculture Engineering, Drnovská 507, CZ161 01 Prague 6, Czech Republic
*Correspondence: cedikj@tf.czu.cz

Abstract:

The development of biofuels for compression ignition engines is heading primarily to utilization of vegetable oils. Combusting of 100% vegetable oil in unmodified CI engine is usually not possible due to higher viscosity of the vegetable oil. In order to use 100% vegetable oil in CI engine the oil needs to be preheated, esterified or hydrotreated. Alternatively, in order to use raw vegetable oil in CI engine without preheating it is possible to use vegetable oil – diesel fuel blends or vegetable oil – butanol – diesel fuel blends in order to lower the viscosity of the fuel. The contribution focuses on comparison of the effect of sunflower and rapeseed vegetable oils on operational parameters of the turbocharged compression ignition engine, especially on production of solid particles. The measurement was carried out according to standardized NRSC test cycle. 5% and 20% concentration of vegetable oils in diesel fuel were used as a test fuels for the measurement while the diesel fuel was used as a reference. The count and size of solid particles were measured by means of EEPS particle analyser. Based on the measured values it can be stated that the slight increase of performance parameters occurred with strong effect on emissions production, especially on production of solid particles.

Key words:

, , , , ,




997-1009 O. Chotovinský and V. Altmann
A comparative case study of the efficiency of collection systems for paper and biodegradable municipal solid waste
Abstract |

A comparative case study of the efficiency of collection systems for paper and biodegradable municipal solid waste

O. Chotovinský* and V. Altmann

Department of Machinery Utilisation, Faculty of Engineering, Czech University of Life Sciences in Prague, Kamycká 129, CZ165 21 Prague 6 – Suchdol, Czech Republic *Correspondence: chotovinsky@tf.czu.cz

Abstract:

The need to increase municipal solid waste recycling rates has led to the study and analysis of recycling schemes from the perspective of the technical issues that may be involved. This paper compares two waste collection systems, which are operating in the Vysočina region of the Czech Republic: a municipal solid waste collection system for paper (including cardboard) and a biodegradable municipal solid waste collection system. Both collection systems were introduced at different times to cover one selected urban area. The emphasis has been placed on an evaluation of the development of individual, separate collections between 2014 and 2016. Analysis of the technological operation and performance of the collections are observed and evaluated by measuring a range of waste collection system indicators. Efficiency levels, especially when it comes to separate collections of both types of municipal solid waste, are compared to their relative representation in the remaining bulk of municipal solid waste. The changes in representation of these types of waste against those in the rest of the municipal solid waste shows which collection systems are more successful from the perspective of the implementation of the directive which covers landfill usage. The results also describe why systems could be more successful within the view of well-chosen or inappropriately-selected technological parameters for materials separation. The possibly statistically significant impact of paper waste production in terms of the relative amount of paper waste across the rest of the municipal solid waste has also been shown.

Key words:

, , , , ,




1010-1016 J. Hart and V. Hartová
Detection reliability for passive infrared detectors in intrusion and hold-up alarm systems and their ergonomics
Abstract |
Full text PDF (639 kB)

Detection reliability for passive infrared detectors in intrusion and hold-up alarm systems and their ergonomics

J. Hart¹* and V. Hartová²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 00 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ165 00 Prague, Czech Republic
*Correspondence: janhart77@gmail.com

Abstract:

Currently it is highly important for detectors to be able to achieve efficiency, reliability, and faultless operation, and to be ergonomic thanks to their assembly and being easy-to-fit. In the case of a proposal for the placement of detectors it is naturally important to determine position of the detector and the type of detector being used, but also to guarantee their capability to be able to detect anything when in use and their user and installation-friendliness. The problem of passive infrared (PIR) detectors affects a large proportion of intrusion and hold-up alarm systems (I&HAS). In a time of increasing property crime, it is highly important for PIR detector to actually be able to detect break-in attempts within the guarded area on a reliable basis and free of error. In the case of the installation of PIR detectors, it is naturally important not only to ensure correct installation, to gauge the external influences which may impact upon the detector and to ensure proper maintenance, but also to guarantee the capability of detection under more arduous conditions. The tests and comparisons which have been conducted examine both the normal operation of the PIR detectors and the ergonomics of these detectors. These tests are important both from an informative perspective and due to the opportunities to be able to develop potential counter-measures which could lead to their improvement.

Key words:

, , ,




1017-1024 J. Hart and V. Hartová
Testing of ISM band at remotes for unlocking vehicles
Abstract |

Testing of ISM band at remotes for unlocking vehicles

J. Hart¹* and V. Hartová²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 00 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ165 00 Prague, Czech Republic
*Correspondence: janhart77@gmail.com

Abstract:

Every modern car has a remote control for wireless unlocking. Wireless drivers for unlocking the vehicle using frequency in the ISM bands. ISM bands are unlicensed bands. They are usually used for industrial, medical and scientific purposes. The question is whether wireless transmission parameters are sufficient and do not violate defined range of ISM band. Another important aspect is the security of the wireless transmissions and any other signal interference. The problem of interference plays an important role in ensuring the quality and safety of wireless communications, especially when wireless networks can be found everywhere. The issues of remote control vehicles is very important due to the resulting security of a guarded vehicle. One of the major risks that may occur are data transmission that the signal is blocked by another signal and the end user does not notice. In this case, does not lock the vehicle nor ensuring its securing security system. Tests which were performed accurately determined the bandwidth of broadcast remote control for each vehicle. Vehicles for which the tests were conducted are standard vehicles used to frequent occurrence. These are the following types: Alfa Romeo, Hyundai, Mercedes, Škoda and Toyota. Subsequently, the analysis was performed of transmission compared with standard broadcast of jammers. All test drivers worked in the band ISM433. These tests clearly demonstrated that not every manufacturer strictly observes ranges of ISM band. This may affect traffic on surrounding licensed bands.

Key words:

, , , ,




1025-1031 V. Hartová, J. Hart and P. Prikner
Influence of face lighting on the reliability of biometric facial readers
Abstract |
Full text PDF (774 kB)

Influence of face lighting on the reliability of biometric facial readers

V. Hartová¹*, J. Hart² and P. Prikner¹

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ165 00 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 00 Prague, Czech Republic
*Correspondence: nverca@seznam.cz

Abstract:

At present, there is an increasing need to protect workplace entry and specially guarded premises. In addition to standard access systems on a chip cards are getting to the fore of biometric identification systems such as readers for fingerprint, biometric scans faces and others. Biometric readers face still improve, but still have a lot of blind spots, thanks to which their reliability and user-friendliness decreases. One such problem is the light intensity in the room where the reading device is located. The varying intensity of the light in the room causes a different illumination of the person’s face. It emphasizes or suppresses the main points of the face that needed for user authorization, and the whole identification process is prolonged and difficult. The reliability value is significantly different from the value given by the manufacturers. It is very important to highlight on this problem and begin to address it by altering the current production engineering.

Key words:

, , , ,




1032-1045 M. Hissa, S. Niemi and K. Sirviö
Combustion property analyses with variable liquid marine fuels in combustion research unit
Abstract |

Combustion property analyses with variable liquid marine fuels in combustion research unit

M. Hissa*, S. Niemi and K. Sirviö

University of Vaasa, School of Technology and Innovations, Department of Energy Technology, P.O. Box 700, FI-65101 Vaasa, Finland
*Correspondence: Michaela.Hissa@uva.fi

Abstract:

The quality of ignition and combustion of four marine and power plant fuels were studied in a Combustion Research Unit, CRU. The fuels were low-sulphur Light Fuel Oil (LFO, baseline), Marine Gas Oil (MGO), kerosene and renewable wood-based naphtha. To meet climate change requirements and sustainability goals, combustion systems needs to be able to operate with a variety of renewable and ‘net-zero-carbon’ fuels. Due to the variations in the chemical and physical properties of the fuels, they generally cannot simply be dropped into existing systems. The aim of this research project was to understand how changes in fuel composition affect engine operation. The focus was on how various properties of the fuels impact on the combustion process – especially ignition delay and in-cylinder combustion. The goal of the research project was to allow broad fuel flexibility without any or only minor changes to engine hardware. Before the engine tests, the CRU forms an easy and cost-effective device to find out the engine suitability of the fuel. The results showed that the ignition delay decreased expectedly with all fuels when the in-cylinder pressure and temperature increased. The differences in the maximum heat release rates between fuels decreased in high-pressure conditions. MGO had the shortest ignition delay under both pressure and temperature conditions. Based on the CRU results MGO and kerosene are suitable to use in compression-ignited engines like the reference fuel LFO. In contrast renewable naphtha had a long ignition delay. If naphtha is used in a CI engine, the engine must be started and stopped with, e.g. LFO or MGO.

Key words:

, , ,




1046-1051 P. Hrabě, Č. Mizera, D. Herák and A. Kabutey
Mechanical behaviour of Sugar palm (Arenga pinnata) fibres
Abstract |
Full text PDF (686 kB)

Mechanical behaviour of Sugar palm (Arenga pinnata) fibres

P. Hrabě¹*, Č. Mizera², D. Herák² and A. Kabutey²

¹University of Life Sciences, Faculty of Engineering, Department of Material Science and Manufacturing Technology, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Czech University of Life Sciences, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: hrabe@tf.czu.cz

Abstract:

The tensile strength of Sugar palm (Arenga pinnata) fibres was examined. Fibre samples were prepared and tested up to the point of rupture with a deformation rate of 0.05 min-1. The tensile device (Labortech, MPTest 5.050, Czech Republic) were used to determine the tensile force. The aim of the paper was to describe a mechanical behaviour of Sugar palm (Arenga pinnata) fibres. Measured values can be used as a basis for further research on the application of Sugar palm fibres.

Key words:

, ,




1052-1061 P. Jirsa and J. Malaťák
Stabilization of persistent organic pollutants (POP) in flue gases in a biological waste incinerating facility
Abstract |
Full text PDF (819 kB)

Stabilization of persistent organic pollutants (POP) in flue gases in a biological waste incinerating facility

P. Jirsa* and J. Malaťák

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Praha-Suchdol *Correspondence: pjirsa@tf.czu.cz

Abstract:

The article focuses on a technology of flue gases stabilization in biological and hospital waste incinerating facility. Hazardous particles and compounds formed in flue gas during the process of thermal waste degradation need to be stabilized according to an enacted legislation. The aim of the research is to examine technological process of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/F) elimination in flue gas. PCDD/F is group of persistent organic pollutants which are resistant to environmental degradation and are highly toxic for the environment in very small amounts. Experiments were performed in semi operation hospital waste incinerating plant with heating power 1.5 MW and capacity 250 kg h-1 of incinerating material. It was observed that formation of PCDD/F exponentially grows with increasing concentration of chlorides in the flue gas, but formation varies based on type of congener. The highest concentration was measured for HxDF, 17,522 pg Nm-3 and HpDF, 16,334 pg Nm-3 at chloride concentration of 867 mg Nm-3. However, concentration of PCDD congeners didn´t exceeded 4,000 pg Nm-3 for the same level of chlorides in flue gas. Two types of activated carbon Chezacarb and NORIT were tested for capability to stabilize PCDD/F in flue gas. Results show that refining effect for both sorbent are very similar. It was observed that 0.1 g of activated carbon should be applied per 1 Nm3 of flue gas in regard to reduce 3–4 ng Nm-3 PCDD/F under required emission limit.

Key words:

, , ,




1062-1068 V. Karpov and T. Kabanen
Improving energy efficiency of biotechnical agricultural systems – scientific and organisational Issues
Abstract |
Full text PDF (630 kB)

Improving energy efficiency of biotechnical agricultural systems – scientific and organisational Issues

V. Karpov¹ and T. Kabanen²*

¹Saint-Petersburg state Agrarian University, Pushkin-1, Box No 1, RU196600 St.-Petersburg, Russia
²Tallinn University of Technology Tartu College, Puiestee 78, EE 51008 Tartu, Estonia *Correspondence: toivokabanen@hot.ee

Abstract:

The production process of an agricultural and industrial complex (AIC) includes processing of big areas of fertile soil that receive sun-generated electromagnetic energy. This is one of the peculiarities of the AIC, determined by the fact that the AIC produces primary (plant-based) food. The plants use part of the sun-generated energy to synthesise biological energy, which forms the nutrition value of the product and which is measured by a rational (relative) factor per unit of area. A plant community is a biological system where each plant is a biological element. The amount of fuel energy (which is anthropogenic unlike sun-generated energy) consumed by an AIC company to produce plant-based food is determined by the energy efficiency of the technical elements (fuel cells, both mobile and immobile) included in the consumer energy system (CES).Crops also supply food for livestock farming, which is the second biological branch of AIC and produces the second type of food, meat and poultry. Animals and poultry are raised using daily feed flow as the source of energy. As the energy consumption and the energy efficiency (expenses and return on investment, respectively) are determined by the technical part of the consumer energy system, it is necessary to find the dependence between the CES and biological systems (crop farming and animal farming) in the food production process.

Key words:

, , ,




1069-1076 V. Kazulis, I. Muižniece and D. Blumberga
Conceptual ‘Cradle to Gate’ analysis of GHG emissions from wood, agricultural plant and synthetic fibres
Abstract |
Full text PDF (637 kB)

Conceptual ‘Cradle to Gate’ analysis of GHG emissions from wood, agricultural plant and synthetic fibres

V. Kazulis*, I. Muižniece and D. Blumberga

Riga Technical University, Faculty of Power and Electrical Engineering, Institute of
Energy Systems and Environment, Azenes iela 12/1, LV-1048 Riga, Latvia
*Correspondence: valters.kazulis@rtu.lv

Abstract:

Industrialization and fossil resource use has brought unprecedented anthropogenic carbon dioxide emissions. Use of synthetic fibre materials and unsustainable plant cultivation practices contribute to greenhouse gas emissions. The global market share of polyester fibre (synthetic fibre made from fossil resources) exceeded the share of cotton fibre (natural fibre) for the first time in 2000 and since then polyester has remained the most popular fibre. The demand for textiles keeps increasing. In Northern Europe locally made fibres from wood, hemp and flax could substitute fossil based fibres decreasing the global GHG emissions and helping local economies to prosper. Multi-criteria analysis method TOPSIS was used to carry out a conceptual research evaluating GHG emissions from wood, agricultural plant and synthetic fibre acquisition under two scenarios: fossil fuels are used as energy sources & industrial fertilizers are used; and renewable energy sources are used & industrial fertilizers are not used. Results show that wood and plant fibres have smaller GHG emissions than synthetic fibres in both scenarios. Factors affecting emission performance are analysed.

Key words:

, , , , , , ,




1077-1084 P. Kic and P. Neuberger
Thermal properties of historic rural building materials in Czechia
Abstract |
Full text PDF (720 kB)

Thermal properties of historic rural building materials in Czechia

P. Kic¹* and P. Neuberger²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: kic@tf.czu.cz

Abstract:

Due to the different natural conditions, various local natural building materials were used for the construction of rural residential and farm buildings in various locations in the Czech Republic. Currently, it is often a requirement for the modernization of relatively old buildings. The buildings were built with different technologies. Very often only locally available material was used. In many cases, the properties of old materials are not available in the literature. However, it is necessary to know the thermal properties of building materials for the preparation of a reconstruction design. Thermal properties of materials are the basis for determination of heat losses of buildings useful for design of heating systems. The aim of this paper is to compare the research results focused on the thermal conductivity of different old construction materials (stones and rocks) and to show examples of preserved historical agricultural buildings. The results presented in this paper are based on the measurements by the portable instrument Isomet 2104. Authors recognised significant differences between tested materials. The mean values of thermal conductivity λm of tested materials: gaize 1.49 W m-1 K-1, artificial marble 1.80 W m-1 K-1, gneiss 2.36 W m-1 K-1, proterozoic shale 2.68 W m-1 K-1, granite 3.66 W m-1 K-1 and quartz sandstone 6.15 W m-1 K-1. Differences between thermal conductivity values of stones and rocks should be respected in calculation of heat balance of new or reconstructed buildings to avoid the problems of the formation of thermal bridges.

Key words:

, , , ,




1085-1094 P. Koder, V. Novák, V. Ryzhenko, D. Hrubý, J. Volf and D. Novák
Plantograf V18 – new construction and properties
Abstract |
Full text PDF (901 kB)

Plantograf V18 – new construction and properties

P. Koder¹, V. Novák¹*, V. Ryzhenko¹, D. Hrubý², J. Volf¹ and D. Novák³

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Electrical and Automation, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Electrical Engineering, Automation and Informatics, Tr. Andreja Hlinku 2, SK949 76 Nitra, Slovakia
³Matej Bel University, Faculty of Natural Sciences, Department of Technology, Tajovského 40, SK974 01 Banská Bystrica, Slovakia
*Correspondence: novakviktor@tf.czu.cz

Abstract:

The article describes Plantograf V18, a planar tactile transducer, which converts the applied pressure into electric signal and enables a graphical presentation of the measured data; the new version V18 comes with some significant improvements and modifications. The device may be used everywhere where the pressure distribution between an object and surface is to be determined, e.g. in medicine or automotive industry. The article contains the detailed description of the transducer design and its electronic control circuits, as well as the yet unpublished measurements of pressure sensitivity with 3.5 mm electrodes.

Key words:

, , , ,




1095-1109 S. Ločs and I. Boiko
Quality assessment of laser cladded HSS coatings with deep penetration into base material to obtain a smooth gradient of properties in coating-substrate interface
Abstract |

Quality assessment of laser cladded HSS coatings with deep penetration into base material to obtain a smooth gradient of properties in coating-substrate interface

S. Ločs¹² and I. Boiko¹*

¹Riga Technical University, Faculty of Mechanical Engineering, Transport and Aeronautics, Institute of Mechanical Engineering, Viskalu street 36A, LV-1006 Riga, Latvia
²Daugavpils University, Faculty of Natural Sciences and Mathematics, Parades street 1, LV-5401 Daugavpils, Latvia
*Correspondence: irina.boiko@rtu.lv

Abstract:

The present research is dedicated to the study of influence of coaxial laser cladding (CLC) process parameters onto values of alloying components content in the coatings, morphology as well as the influence of post-cladding heat treatment on the quality and mechanical properties of coatings. The research is based on a hypothesis that applying of first layer of coatings onto steel substrate with keyhole in penetration allows achieving smooth gradient of properties of the coating-substrate system. As a result it may provide a smooth distribution of the internal residual stresses in interface as well as the better resistance to external stress during cyclic load in tool operation processes: metal forming, stamping etc. Experimental work was carried out using CLC system, which consists of industrial robot Kuka and 1 kW IPG Yb-fiber laser, integrated to the coaxial powder supplying cladding head. The regularities of formation of High Speed Steel AISI М2 cladding coatings created by different regimes were studied by deposition onto EN 41Cr4 and C80U steel substrates. The quality of achieved coatings has been evaluated by examination of morphology of transverse cross-sections, coatings geometrical features, elemental composition and microhardness distribution inside coatings. Additionally detailed assessment of coating thickness and content of alloying elements using statistical methods has been performed. As a result of the research done the degree of influence of chosen CLC process parameters onto quality characteristics were estimated. The most appropriate cladding regime for used method was proposed.

Key words:

, , ,




1110-1117 D. Marčev and M. Kotek
Influence of the road profile in different geographical areas of the Czech Republic to the operational parameters of the electric vehicle
Abstract |
Full text PDF (1,005 kB)

Influence of the road profile in different geographical areas of the Czech Republic to the operational parameters of the electric vehicle

D. Marčev* and M. Kotek

Czech University of Life Science Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ165 00 Prague, Czech Republic
*Correspondence: marcev@tf.czu.cz

Abstract:

The aim of this paper is to compare the operating parameters of the full-electric vehicle VW e-up! operated in two significantly different geographic areas of the Czech Republic. The first tested area was the lowland area in the vicinity of municipality Mělník; the second area was a hilly area near the municipality of Ústí nad Labem with frequent and very sharp altitude changes. During measurement, the operating parameters of the battery (voltage, level) and electric motor (instantaneous voltage and current) were recorded. The results show a surprisingly small difference in vehicle tank range in both compared regions because the recuperation in the hilly area was used very often. It is possible to conclude that these electric vehicles can be used for everyday commuting under conditions of different geographical areas.

Key words:

, , ,




1118-1123 Č. Mizera, D. Herák, P. Hrabě and A. Kabutey
Extraction of oil from rapeseed using duo screw press
Abstract |
Full text PDF (603 kB)

Extraction of oil from rapeseed using duo screw press

Č. Mizera¹*, D. Herák¹, P. Hrabě² and A. Kabutey¹

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ165 21 Praha 6 Suchdol, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Material Science and Manufacturing Technology, Kamýcká 129, CZ165 21 Praha 6 Suchdol, Czech Republic
*Correspondence: mizera@tf.czu.cz

Abstract:

This study was focused on the analysis of optimize the pressing process of rapeseeds (Brassica napus L.) using screw press. For pressing of oil a screw press Farmer 20 – duo (Farmer 20, Farmet a.s., Ceska Skalice, Czech republic) was used. The screw rotation speed 10, 20, 30, 40, 55 and 65 rpm was used. Oil recovery efficiency and specific mechanical energy were decreased when the seed material throughput was increased. It has been found that the optimal operation point for screw press Farmer 20 – duo was at 20 kg h-1 rapeseed throughput. The specific mechanical energy at the optimal operation point was 0.61 kWh kgoil-1 Maximum oil recovery efficiency 82.6% was found at the lowest screw speed.

Key words:

, ,




1124-1132 I. Muizniece, V. Kazulis, L. Zihare, L. Lupkina, K. Ivanovs and D. Blumberga
Evaluation of reed biomass use for manufacturing products, taking into account environmental protection requirements
Abstract |
Full text PDF (524 kB)

Evaluation of reed biomass use for manufacturing products, taking into account environmental protection requirements

I. Muizniece*, V. Kazulis, L. Zihare, L. Lupkina, K. Ivanovs and D. Blumberga

Riga Technical University, Institute of Energy Systems and Environment, Azenes iela 12/1, LV-1048 Riga, Latvia
*Correspondence: indra.muizniece@rtu.lv

Abstract:

In many countries reed is considered as invasive or unnecessary plant, because it is spreading rapidly, causing decrease in biodiversity and creating unacceptable living conditions for many bird species in their natural habitats. Due to environmental considerations it is necessary to cut reed, to decrease their over exceeding growth. Reed burning or leaving for decomposition on fields, that has been practiced until now, creates additional carbon dioxide air pollution. Therefore, the question on what to do with cut reed has become vital from environmental protection perspective. In addition, this question applies to bioeconomy principles in compliance with their use in national economy, which makes it clear, that solutions for the use of reed biomass for production have to be found. But any production process can leave a negative effect on surrounding environment. Further to product production, economic motivation, possible market and availability of resources are primarily essential to see whether it is worth to produce the product at all. Therefore, reed biomass use possibilities in production have to be analysed as a complex question, taking into account environmental and climate, economic and technological aspects. In this study, solutions to perspective reed biomass use are evaluated, considering environmental protection requirements. For this task, multi-criteria analysis method TOPSIS is used, which includes 11 environmental and climate, economic and technological criteria. Evaluation includes both – already existing and new products that are divided in 3 sectors: power industry, construction and other products. Results of the research clearly state, which of reed biomass made products are perspective, taking into account not only traditional economic and technological aspects, but also environmental and climate aspects.

Key words:

, , ,




1133-1141 M. Obergruber, V. Hönig, P. Procházka and J. Táborský
Diagnostics of hydraulic fluids used in aviation
Abstract |
Full text PDF (718 kB)

Diagnostics of hydraulic fluids used in aviation

M. Obergruber¹, V. Hönig¹*, P. Procházka² and J. Táborský¹

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ16521 Prague 6, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Economics and Management, Department of Economics, Kamýcká 129, CZ16521 Prague 6, Czech Republic
*Correspondence: honig@af.czu.cz

Abstract:

Diagnostics is a maintenance industry that monitors performance, parameters, and follow–up. Diagnosing hydraulic fluids means comparing the parameters of the used hydraulic fluid sample to the parameters of the clean fluid. It is also essential to monitor the limit values either by the aircraft manufacturer or by the manufacturer of the hydraulic fluid. This means that the manufacturer recommends the limitations of the liquid parameters. The measurements of the fluid samples give an overview of the liquid quality. Most businesses focus on so–called proactive maintenance. The main senses and objectives of proactive maintenance are: lubricant sample analysis, lubricant status, machine status, next step recommendation, database saving and trend analysis. This article focuses on the quality of hydraulic fluid focused in aviation. The aim of the article was to determine the properties of the hydraulic fluid used in the A320 aircraft family, determine the interval of its exchange. Monitoring the state of the hydraulic fluid could contribute to the timely detection of the problem, thus avoiding a failure of the device or the system as a whole. The tracking proposal is an integral part of this article.

Key words:

, , , ,




1142-1149 V. Obuka, M. Boroduskis, A. Ramata-Stunda, L. Klavins and M. Klavins
Sapropel processing approaches towards high added-value products
Abstract |
Full text PDF (503 kB)

Sapropel processing approaches towards high added-value products

V. Obuka¹, M. Boroduskis², A. Ramata-Stunda², L. Klavins¹ and M. Klavins¹*

¹University of Latvia, Department of Environmental Science, Raina Blvd. 19, LV-1586 Riga, Latvia
²University of Latvia,Faculty of Biology, Raina Blvd. 19, LV-1586 Riga, Latvia
*Correspondence: maris.klavins@lu.lv

Abstract:

Sapropel is an organic sediment from fresh water bodies that is widely distributed in the northern regions of the world. The distribution and unique properties of sapropel make it an important natural resource that can be used in agriculture, horticulture, forestry and farming directly as obtained. The aim of this study was to investigate the extraction possibilities of sapropel and potential applications of its extracts. Humic substances constitute an important ingredient of sapropel, and they can be extracted by mild alkaline extraction. Humic substances from peaty sapropel have significant differences in composition and properties, thus demonstrating the impact of precursor biological materials on the properties of humic substances formed in the humification process.

Key words:

, , , ,




1150-1158 T. Olšan, B.M. Soucase and M. Libra
Comparison of predicted and real parameters of PV systems in the Czech Republic and Spain
Abstract |

Comparison of predicted and real parameters of PV systems in the Czech Republic and Spain

T. Olšan¹, B.M. Soucase² and M. Libra¹

¹Czech University of Life Science, Kamycka 129, CZ16521 Prague, the Czech Republic
²Universitat Politecnica de Valencia, Camino de Vera, Applied Physics, ES46022 Valencia, Spain
*Correspondence: tolsan@email.cz

Abstract:

This paper compares predicted performance by a simulation software for a given new constructed PV system of crystalline silicon technology located in Prague with 10 kWp peak power and a similar system in Spain. Simulation software used for the sake of this paper was publicly available PVGIS from the website of its creators, parameters were set to be the same like in the real PV system. The difference between the predicted and the real data was calculated and then discussed in the result section of this paper. Suggestion how to increase the accuracy of the prediction by the simulation software is in the discussion part of this paper.

Key words:

, , ,




1159-1168 T. Ovaska, S. Niemi, T. Katila and O. Nilsson
Exhaust particle size distributions of a non-road diesel engine in an endurance test
Abstract |
Full text PDF (958 kB)

Exhaust particle size distributions of a non-road diesel engine in an endurance test

T. Ovaska¹*, S. Niemi¹, T. Katila² and O. Nilsson¹

¹University of Vaasa, School of Technology and Innovations, P.O. Box 700, FI-65101 Vaasa, Finland
²AGCO Power Oy, Linnavuorentie 8–10, FI37240 Linnavuori, Nokia, Finland
*Correspondence: teemu.ovaska@uva.fi

Abstract:

The main objective of this study was to find out how the non-road diesel engine running period of 500 hours affects the exhaust particle size distribution. By means of an engine exhaust particle sizer (EEPS), particle number was measured before the endurance test and after 250 and 500 hours of engine operation. The size distributions were determined at full and 75% loads both at rated and at intermediate speeds. The soot, gaseous emissions and the basic engine performance were also determined and lubricating oil was analysed a few times during the running period. A blend of low-sulphur fossil diesel and soybean methyl ester (B20) was used as fuel in the 4-cylinder, turbocharged, intercooled engine which was equipped with a diesel oxidation catalyst (DOC) and a selective catalytic reduction (SCR) system. All emissions were measured downstream the catalysts. During the 500 hours of operation, the particle number increased considerably within an approximate size range of 7 to 30 nm. Between the initial and final measurements, no notable differences were observed in the particle number emissions within a particle size range of 50 to 200 nm. The copper content of lubricating oil also increased significantly during the 500 hours’ experiment. One possible reason for the substantial increase in the nucleation mode particle number was assumed to be copper, which is one of the metallic elements originating from engine wear. The engine efficiency was almost equal, and the differences both in smoke and hydrocarbon emission were negligible throughout the 500 hours’ experiment.

Key words:

, , , ,




1169-1177 V. Papez and S. Papezova
Capacitive frost depth indicator
Abstract |
Full text PDF (675 kB)

Capacitive frost depth indicator

V. Papez¹ and S. Papezova²*

¹Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Electrotechnology, Technicka 2, CZ166 27 Pague 6, Czech Republic
²Czech University of Life Sciences in Prague, Faculty of Engineering, Department of Electrical Engineering and Automation, Kamycka 129, CZ165 21 Prague 6 ˗ Suchdol, Czech Republic
*Correspondence: papezovas@tf.czu.cz

Abstract:

The depth of soil freezing, i.e., the depth at which water is frozen, is a significant factor in meteorology, as it affects many processes in agriculture, building, etc. Soil frost penetration is an important factor for overwintering organisms, but also for physical and chemical processes in soil, particularly for its mechanical properties. The depth of freezing is normally determined directly, i.e. mechanically, using a special soil freezing meter, i.e., frost-depth indicator, according to the process of water freezing in the probe. Another method lies in determining the soil temperature by the interpolation of the curves from the graph, as measured by soil thermometers according to the change in the resistivity of soil or water, when frozen. The principle of the frost-depth indicator function is to evaluate the temperature dependence of water permittivity, which decreases, when water is frozen, from εr ~ 87 at 1 °C to εr ~ 3.2 at -1 °C, typical for ice. The water permittivity is evaluated by a measuring capacitor, which is adapted into the shape of the frost depth indicator probe, whose dielectric is deionized water. During freezing, the capacity is reduced in this area. The capacity of the partially frozen probe is directly proportional to the length of its non-frozen section. The measuring capacitor is a part of the resonant circuit of the oscillator. The frequency of the oscillator varies with the capacity of the probe and is further evaluated. The achievable measurement accuracy is approximately 2% for the probe of a 1 m length and in direct evaluation by an autonomous counter. For the computer evaluation, with the possibility to compensate the probe non-linearity, the measurement accuracy is approximately 0.5%.

Key words:

, ,




1178-1189 S. Papezova and V. Papez
Battery capacity drop during operation
Abstract |
Full text PDF (635 kB)

Battery capacity drop during operation

S. Papezova¹* and V. Papez²

¹Czech University of Life Sciences in Prague, Faculty of Engineering, Department of Electrical Engineering and Automation, Kamycka 129, CZ165 21 Prague 6 ˗ Suchdol, Czech Republic
²Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Electrotechnology, Technicka 2, CZ166 27 Pague 6, Czech Republic
*Correspondence: papezovas@tf.czu.cz

Abstract:

A lithium-iron-phosphate (LiFePO4) battery is nowadays considered one of the best types of batteries. The paper deals with the evaluation of the drop in their capacity during operation. Based on the physical analysis of charging and discharging processes, a mathematical model of the battery capacity has been developed during its lifetime. The decrease in capacity during battery operation is evaluated according to the loss of active material, which gradually diminishes due to a number of different processes. The analysis of the loss of the active material is carried out, in particular, according to the depth of discharge, battery temperature, charging and discharging time, including the time when the battery is out of service. The tests were performed on the Winston Battery, Calb, Thunder Sky and Sinopoly batteries by cyclic discharging and charging at the 50%, 90% or 100% depth of discharge. Their real parameters were determined, compared to the model parameters and the parameters specified by the manufacturers and suppliers. Two automated systems were used for testing. During the test, in the tested battery with several cells, charging and discharging by a constant current were carried out automatically. Operating parameters of the tested battery were continuously scanned, recorded and evaluated by the control computer. The capacity curves during the battery operation, determined by the type of models, were compared with the results of long-term real battery tests.

Key words:

, , ,




1190-1199 M. Pexa, J. Čedík, B. Peterka and M. Holůbek
The operational parameters and emissions of portable generator after long-term operation on n-butanol
Abstract |

The operational parameters and emissions of portable generator after long-term operation on n-butanol

M. Pexa, J. Čedík*, B. Peterka and M. Holůbek

Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ165 21 Prague 6, Czech Republic
*Correspondence: cedikj@tf.czu.cz

Abstract:

The utilization of biofuels in spark ignition and compression ignition engines is the trend of the recent time. The great expectations are inserted into n-butanol as a fuel, especially for spark ignition engines. The short time use of n-butanol in the SI (spark ignition) combustion engine does not make a big problem (start of the cold engine, change of the air-fuel ratio). The purpose of this contribution is the effect of long-term use of n-butanol as a fuel for SI engine. For this purpose the small portable generator was used. The harmful emissions, fuel consumption and power of the generator was measured then the generator was operated for 300 hours on 100% n-butanol with 80% of nominal load and the measurement was repeated. The generator was loaded with adjustable electrical resistance. As a reference fuel the petrol BA 95 with no bio-component was used. During the operation on n-butanol no technical problems occurred with the generator. After 300 hours of operation on n-butanol the performance parameters slightly decreased with little impact on production of harmful emissions components.

Key words:

, , , ,




1200-1208 M. Polák
Determination of conversion relations for the use of small hydrodynamic pumps in reverse turbine operation
Abstract |
Full text PDF (977 kB)

Determination of conversion relations for the use of small hydrodynamic pumps in reverse turbine operation

M. Polák

Czech University of Life Sciences in Prague, Faculty of Engineering, Kamýcká 129, CZ16521, Praha 6, Czech Republic
Correspondence: karel@tf.czu.cz

Abstract:

In small-scale hydropower, hydrodynamic pumps used in reverse mode are an important economical alternative to conventional water turbines. Efficient utilisation of these devices however requires taking into account all the specifics of the reverse pump operation and optimise the pump design for maximum utilisation of the hydro-technical potential of the deployment site. The article compares existing conversion models, describes initial theoretical assumptions and determines new conversion relations for the design of pumps as turbines (PAT) for the lowest power and specific speed category. The validity of the conversion relations is experimentally verified on a hydraulic test circuit with a radial centrifugal pump tested in both pump and turbine operation modes. The results of the verification of the new conversion relations proved better correspondence to reality within this category of machines than that reported by the previously used conversion models.

Key words:

, , , ,




1209-1217 K. Pužuls, T. Štāls, A. Zimelis and A. Lazdiņš
Preliminary conclusions on application of ultrasonic sensors in evaluation of distribution and depth of ruts in forest thinning
Abstract |
Full text PDF (782 kB)

Preliminary conclusions on application of ultrasonic sensors in evaluation of distribution and depth of ruts in forest thinning

K. Pužuls, T. Štāls, A. Zimelis and A. Lazdiņš*

Latvian State forest Research Institute 'Silava', Rīgas street 111, LV-2169 Salaspils, Latvia
*Correspondence: andis.lazdins@silava.lv

Abstract:

The scope of the study is to elaborate equipment for measurement of ruts during log forwarding. The system is supposed to be used in practical forestry to replace manual measurement of length of deep ruts and to provide spatially explicated information on soil bearing capacity, which can be used in planning of forest operations.
A set of 4 pairs of ultrasonic sensors were installed on front and rear bunks to measure distance to the ground at 90o angle (in front and behind the wheels in each side of forwarder) and at certain angle to measure distance to the ground outside strip-road. Measurement data are sent to the logger, where they are stored in .csv files. Wired connection between the sensors and the logger was used in earlier version, but later replaced with wireless connection. Depth of rut is calculated using formula for calculation of length of cathetus of a right-angled triangle. Data processing in spreadsheet includes initial identification of error values and calculation of depth of ruts. Further spatial data analysis is done in GIS software.
According to the study results ultrasonic sensors provides sufficient accuracy to characterize depth of ruts in 1…5 m long segments of strip-roads, including dynamic data on depth and length of ruts after each pass. However, the accuracy is insufficient to compare measurements from sensors mounted on front and rear bunks, as well as on left and right side of machine, therefore it is enough to have 2 pairs on sensors on rear bunks.

Key words:

, ,




1218-1227 R. Rannaveski and M. Listak
Flash points of gasoline from Kukersite oil shale: Prediction from vapor pressure
Abstract |
Full text PDF (895 kB)

Flash points of gasoline from Kukersite oil shale: Prediction from vapor pressure

R. Rannaveski and M. Listak*

Tallinn University of Technology, School of Engineering, Department of Energy Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia
*Correspondence: madis.listak@ttu.ee

Abstract:

The flash point of liquid fuels, especially of light distillates such as gasoline or naphtha, is an important parameter for the handling of such materials. In this work, flash points and volatility characteristics (vapor pressure, boiling point) of a number of shale gasoline samples with different volatilities were measured. The shale gasoline fractions were produced from Kukersite oil shale using solid heat carrier retorting technology. Several existing correlations for calculating flash points of hydrocarbons and petroleum fractions are evaluated, and the absolute average deviations were found to be between 1.1 to 20.9 °C. New, easy-to-use correlations are proposed for estimating flash points for oil shale based gasolines from volatility characteristic that are readily available. The correlation proposed in this work are based on the vapor pressure at 20 or 37.8 °C (100 °F), Reid vapor pressure (37.8 °C) or boiling point. The average absolute deviations for these correlations were 0.82 to 0.93 °C, meaning they are comparable to or better than existing methods developed for petroleum oils, which mostly use boiling point as the input parameter, when applied to gasoline from Kukersite oil shale.

Key words:

, , , , , , , , ,




1228-1236 H. Roubík, J. Mazancová, A. Brunerová and D. Herák
Factors influencing use of fuelwood and its environmental impacts in Tapanuli Utara regency, North Sumatra
Abstract |
Full text PDF (801 kB)

Factors influencing use of fuelwood and its environmental impacts in Tapanuli Utara regency, North Sumatra

H. Roubík¹*, J. Mazancová¹, A. Brunerová² and D. Herák³

¹Department of Sustainable Technologies, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Kamýcká 129, CZ165 00 Prague, Czech Republic
²Department of Material Science and Manufacturing, Faculty of Engineering, Czech University of Life Sciences Prague, Kamýcká 129, CZ165 00 Prague, Czech Republic
³Department of Mechanical Engineering, Faculty of Engineering, Czech University of Life Sciences Prague, Kamýcká 129, CZ165 00 Prague, Czech Republic
*Correspondence: roubik@ftz.czu.cz

Abstract:

Deforestation and forest degradation, after burning of fossil fuels, is considered as the second leading cause of anthropogenic greenhouse emissions (accounting for over 17% of global carbon dioxide emissions) and has become an important issue concerning climate change mitigation. The provision of wood energy is generally thought to be a major contributor to forest loss. In Indonesia, more than half of the rainforest there, the third-largest swath in the world, has been felled in just a few years. Furthermore, permission has been granted to convert the majority of what remains into palm or acacia plantations. The logging and burning of forests to clear land for cultivation has made Indonesia one of the largest emitters of greenhouse gases. Therefore, the objective of this study was to assess the current level and influencing factors of the use of fuelwood among the rural population as well as the consequent environmental impacts in the target area in North Sumatra. The questionnaire survey using randomly selected households (n = 196) was administered in Tapanuli Utara regency from July to August 2014; followed by several field visits from August to September 2016. Obtained data were analysed with descriptive statistics and cross tabulation. The results indicate that fuelwood is a significant source of energy in the target area. For 31% of respondents it is the major energy source and for 64% it is a supplementary source. The high rate of use of wood as fuel corresponds to the poor financial situation of respondents and the easy accessibility of wood, but only from the surrounding area (own garden or adjacent land). Wood resources are often very distant (on average over 1,000 metres) as a consequence of high deforestation. This study reveals that there is a non-sustainable trend of forest conversion resulting in high land degradation in Tapanuli Utara regency.

Key words:

, , ,




1237-1246 K. Sirviö, S. Heikkilä, R. Help, S. Niemi and E. Hiltunen
Properties of local produced animal-fat based biodiesel and its blend with fossil fuel
Abstract |
Full text PDF (638 kB)

Properties of local produced animal-fat based biodiesel and its blend with fossil fuel

K. Sirviö*, S. Heikkilä, R. Help, S. Niemi and E. Hiltunen

University of Vaasa, Faculty of Technology, PL 700, FIN-65101 Vaasa, Finland
*Correspondence: katriina.sirvio@uva.fi

Abstract:

In the near future, more emphasis must be put on reducing greenhouse gas (GHG) emissions in road transportation, house heating, agricultural activities, marine transport etc. This study concentrated on the use of alternative fuels in engine-driven applications of non-road machineries and decentralized energy production. Today, the engines are mainly designed for crude oil derived fuels and liquid renewable fuels are blended with crude oil based fuels to fulfill the requirements of renewable energy usage. Due to the environmental reasons on one hand and to the agricultural needs, on the other hand, different blends of bio- and fossil fuels are becoming more popular. In Europe, the maximum FAME content in diesel fuel is 7 vol% according to the EN 590:2013 but higher percentages are also available and targeted around the world. For example in the United States, the 20% blend fraction is becoming more common. For these reasons, B20 fuels were chosen to be investigated in this study. Special emphasis was put on improving blending issues since fuel blending may cause some operating risks. The main aim was to research widely the properties of animal-fat based methyl ester (AFME) and B20 fuel blend produced from it. AFME is a waste based fuel and produced in Ostrobothnia region, Finland. The aim was to find out in which engine applications the fuels are feasible and investigate if the fuels fit in the quality of automotive fuel Standards. According to the results, AFME is a feasible option to increase self-sufficient energy production in Ostrobothnia.

Key words:

, , , , ,




1247-1256 K. Sirviö, S. Niemi, R. Help, S. Heikkilä and E. Hiltunen
Kinematic viscosity studies for medium-speed CI engine fuel blends
Abstract |
Full text PDF (807 kB)

Kinematic viscosity studies for medium-speed CI engine fuel blends

K. Sirviö*, S. Niemi, R. Help, S. Heikkilä and E. Hiltunen

University of Vaasa, Faculty of Technology, PL 700, FIN-65101 Vaasa, Finland
*Correspondence: katriina.sirvio@uva.fi

Abstract:

Engine-driven power plants, run by diesel fuel or gas, will be needed for peaking power to keep the electricity grids stable when the production of renewable electricity, e.g. utilizing wind or solar power, is increased.
The choice of the alternative, renewable fuels for engine-driven power plants and marine applications is at the moment quite narrow. The amount of renewables of all liquid fuels is at present less than 2%. Biodiesels, FAMEs, have been studied for long time and apparently, despite of the problems they may have, they are still in the great interest. One important increment to the category of alternatives is fuels that are produced from e.g. oil wastes, i.e., recycled fuels. They are not renewable, but recycling of potential energy raw materials is still one step forward in increasing the suitable and more sustainable options.
To utilize the blends in medium-speed engines for power production, accurate knowledge of the physical and chemical properties of fuel blends is very important for the optimization of engine performance. The determination of the fuel kinematic viscosity is needed to create proper fuel atomisation. The injection viscosity affects directly the combustion efficiency and the engine power. Consequently, this study focused on measuring kinematic viscosity curves for seven fuel blends, as well as the neat fuels used for blending. The temperature range was 10–90 °C. The fuels used for blending were rapeseed methyl ester, animal-fat based methyl ester, hydro-treated vegetable oil, light fuel oil and marine gas oil produced from recycled lubricating oils.

Key words:

, , , , ,




1257-1265 M. Tichý, M. Müller, P. Valášek and I. Miturska
Effect of rubber powder from waste tyre rubbers on mechanical properties of one-component polyurethane putty
Abstract |
Full text PDF (827 kB)

Effect of rubber powder from waste tyre rubbers on mechanical properties of one-component polyurethane putty

M. Tichý¹*, M. Müller¹, P. Valášek¹ and I. Miturska²

¹Czech University of Life Sciences, Faculty of Engineering, Department of Material Science and Manufacturing Technology, Faculty of Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Lublin University of Technology, Department of Production Engineering, Mechanical Engineering Faculty, Nadbystrzycka 36, PL20 618 Lublin, Poland
*Correspondence: xticm001@studenti.czu.cz

Abstract:

The utilization of adhesives in technical practice is varied. Adhesives serve for a creation of strength bonds on the one hand, and on the other hand e.g. for cementing. The aim of the research is a modification of one-component polyurethane putty RPS 45 used in automotive industry to increase strength properties in an adhesive bond. An interaction between a filler in the form of rubber powder micro-particles and one-component polyurethane adhesive was investigated by means of SEM analysis. Sealing is a primary property of this putty. Sealing putties usually reach very small strength which can be increased by an admixture of the filler. In order to keep elastic properties, micro-particles of the rubber powder gained from tyre recycling process were used as the filler. An aspect of a loading speed of the adhesive bond is essential at the practical application at which the adhesive bond can be failed in adhesive or cohesive layers. The adhesive bond can be perceived in terms of its function as a complex of three layers, i.e. an adhesive bonded material, the interaction between the adhesive and the adhesive bonded material and the adhesive layer itself. There are often states in the practices when the adhesive bonds are exposed to the loading which can be either a static or a dynamic one. That is why the research is focused not only on the evaluation of the influence of the modification of the one-component polyurethane adhesive, but also on the influence of the loading speed of the adhesive bond. Tested speeds set on a universal testing machine Zwick/Roell Z150 were 2, 50 and 100 mm min-1. The results of mechanical tests proved a positive influence of the filler on the strength σm higher by 42.68 ± 6.96% and the elongation at break εb higher by 12.2 ± 20.95%. On the contrary, the stress at yield σy was decreased.

Key words:

, , , , , ,




1266-1277 R. Tretjakova, A. Martinovs, M. Avisane and G. Kolcs
Lake blue clay – sapropel – flax shive briquettes for water absorption and desorption
Abstract |
Full text PDF (1,008 kB)

Lake blue clay – sapropel – flax shive briquettes for water absorption and desorption

R. Tretjakova*, A. Martinovs, M. Avisane and G. Kolcs

Rezekne Academy of Technologies, Faculty of Engineering, Atbrīvošanas aleja 115/K-4, LV-4601 Rēzekne, Latvia
*Correspondence: rasma.tretjakova@rta.lv

Abstract:

Latvian lakes are rich in sapropel sediments and below the sapropel layer there is another valuable natural resource, namely blue clay. Flax shives are formed in large quantities as a waste in flax processing factories. The problem involves processing and rational use of these resources. The paper studies the obtaining of briquettes from flax shives using sapropel and lake clay as a binding material. Briquettes are intended for use in cases when problems with regular plant watering occur. For example, provision of plants with water in greenhouses, indoor spaces for a long period of time without human presence. Briquettes are placed into the soil next to the plant roots. Briquettes are initially moistened and absorb a significant amount of water (moisture content to be expressed in comparison to the sample’s dry weight 250–380%). The presence of clay in them contributes to slow drying of briquettes and provides a long lasting supply of moisture to the plant roots. The paper deals with the issues of the optimal composition of components and the amount of pressure for the production of briquettes, as well as water absorption and desorption properties of briquettes. The aim of the study is to develop a production method of clay – sapropel – flax shive briquettes with good water absorption and desorption properties.

Key words:

, , ,




1278-1288 J. Volf, F. Škeřík and V. Novák
Technical design of complex vision-tactile navigation system for using of blind persons navigation
Abstract |

Technical design of complex vision-tactile navigation system for using of blind persons navigation

J. Volf, F. Škeřík and V. Novák*

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Electrical and Automation, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: novakviktor@tf.czu.cz

Abstract:

This article presents the system used for navigation and orientation of blind persons in an unknown terrain. This system called ‘Tactile Navigation System’ constitutes a compensation instrument for blind persons. It is composed from three basic elements: a camera, a control unit and a tactile activator. The tactile navigation system converts the image from the camera to the tactile information and it transfers this information to the blind person. The blind person can recognize by vibration of the tactile activator placed on the antebrachium whether he comes on an impediment or if he can continue free walking. The main advantage of this system is the possibility of detecting any individual impediment earlier than using other common compensation tools, such as a simple blind stick, which is not a competitor with this device, but a helper. This way the system facilitates the orientation of a blind person an in an unknown terrain. The article describes in detail the overall composition and functionality of the system as well as the principle and function of its individual elements.

Key words:

, , , , ,




1289-1294 A. Yonetken and A. Erol
Production and characterization of Al-BN composite materials using by powder metallurgy
Abstract |
Full text PDF (795 kB)

Production and characterization of Al-BN composite materials using by powder metallurgy

A. Yonetken¹* and A. Erol²

¹University of Afyon Kocatepe, Faculty of Engineering, Department of Electrical Engineering, ANS campus, TR03200 Afyonkarahisar, Turkey
²University of Afyon Kocatepe, Faculty of Technology, Department of Metallurgy and Materials Engineering, ANS campus, TR03200 Afyonkarahisar, Turkey
*Correspondence: yonetken@aku.edu.tr

Abstract:

Aluminum matrix composites containing 3, 6, 9, 12 and 15% BN has been fabricated by conventional microwave sintering at 550 °C temperature. Compounds formation between Al and BN powders is observed after sintering under Ar shroud. XRD, SEM (Scanning Electron Microscope), mechanical testing and measurements were employed to characterize the properties of Al + BN composite. Experimental results suggest that the best properties as hardness 42, 62 HV were obtained for Al+12% BN composite.

Key words:

, ,