2018, Vol. 16, Special Issue 1

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/5379

Sirvi

Nüüd näidatakse 1 - 20 38

Crop weight measurement sensor for IoT based industrial greenhouse systems
(2018) Avotins, A.; Potapovs, A.; Apse-Apsitis, P.; Gruduls, J.
No wadays 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 solution s. 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 hav e 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 prod uction, therefore this research is conducted in cooperation with tomato producing industrial greenhouse of SIA ‘ Latgales darzenu logistika ’ focusing on IoT based crop weight measurement.
Development and testing results of IoT based air temperature and humidity measurement system for industrial greenhouse
(2018) Avotins, A.; Apse-Apsitis, P.; Bicāns, J.; Gruduls, J.
In dustrial 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 solut ions. 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.
Production and characterization of Al-BN composite materials using by powder metallurgy
(2018) Yonetken, A.; Erol, A.
Aluminum matrix composites containing 3, 6, 9, 12 and15% 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. Exper imental results suggest that the best properties as hardness 42, 62 HV were obtained for Al+12% BN composite.
Diagnostics of hydraulic fluids used in aviation
(2018) Obergruber, M.; Hönig, V.; Procházka, P.; Táborský, J.
Diagnostics is a maintenance industry that monitors performance, parameters, and follow – up. Diagnosing hydraulic fluids means comparing the parameters of the used hydr aulic fluid sample to the parameters of the clean fluid. It is also essentia l 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 sta tus, 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 ai rcraft 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.
Effect of sunflower and rapeseed oil on production of solid particles and performance of diesel engine
(2018) Čedík, J.; Pexa, M.; Holůbek, M.; Mader, D.; Pražan, R.
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 orde r 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 e ffect 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% con centration 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.
The operational parameters and emissions of portable generator after long-term operation on n-butanol
(2018) Pexa, M.; Čedík, J.; Peterka, B.; Holůbek, M.
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 g enerator 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 t he performance parameters slightly decreased with little impact on production of harmful emissions components.
Sapropel processing approaches towards high added-value products
(2018) Obuka, V.; Boroduskis, M.; Ramata-Stunda, A.; Klavins, L.; Klavins, M.
Sapropel is an organic sediment from fresh water bodies that is widely distributed in the northern regions of the w orld. 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 investigat e 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 signifi cant differences in composition and properties, thus demonstrating the impact of precursor biological materials on the properties of humic substances formed in the humification process .
Investigation into the performance characteristics of electric automobiles by means of a data logger
(2018) Berjoza, D.; Pīrs, V.; Jurgena, I.
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. Th e 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 w as 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 discharge d 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.
Plantograf V18 – new construction and properties
(2018) Koder, P.; Novák, V.; Ryzhenko, V.; Hrubý, D.; Volf, J.; Novák, D.
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 ev erywhere 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.
Technical design of complex vision-tactile navigation system for using of blind persons navigation
(2018) Volf, J.; Škeřík, F.; Novák, V.
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 a ctivator 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 a s 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 s ystem as well as the principle and funct ion of its individual elements.
A comparative case study of the efficiency of collection systems for paper and biodegradable municipal solid waste
(2018) Chotovinský, O.; Altmann, V.
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 th e 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 ra nge 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 d escribe 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 amou nt of paper waste across the rest of the municipal solid waste has also been shown.
An assessment of stratification of exhaust gases from gasoline and diesel engine
(2018) Birkavs, A.; Smigins, R.
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 vehicl es (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 unregulat ed 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 pr oblems 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.
Experimental research on compatibility of mineral and biobased hydraulic oils
(2018) Birkavs, A.; Smigins, R.
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 e cosystem. 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 mine ral 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 mine ral and biological hydraulic oils do not change its original appearance. It was observed that the highest viscosity 71 mm 2 s - 1 and worst anti - friction properties is for the 50% mix of mineral and biologial hydraulic oil at 20 °C ambient temperature.
Conceptual ‘Cradle to Gate’ analysis of GHG emissions from wood, agricultural plant and synthetic fibres
(2018) Kazulis, V.; Muižniece, I.; Blumberga, D.
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 po lyester 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 Eur ope 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 G HG 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.
Effect of rubber powder from waste tyre rubbers on mechanical properties of one-component polyurethane putty
(2018) Tichý, M.; Müller, M.; Valášek, P.; Miturska, I.
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 i nteraction 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 pra ctical 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 evalu ation 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 r esults of mechanical tests proved a positive influence of the filler on the strength σ m higher by 42.68 ± 6.96% and the elongation at break ε b higher by 12.2 ± 20.95%. On the contrary, the stress at yield σ y was decreased.
Factors influencing use of fuelwood and its environmental impacts in Tapanuli Utara regency, North Sumatra
(2018) Roubík, H.; Mazancová, J.; Brunerová, A.; Herák, D.
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. Further more, 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 o bjective 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 se lected 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 indic ate 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 respo ndents 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.
Quality assessment of laser cladded HSS coatings with deep penetration into base material to obtain a smooth gradient of properties in coating-substrate interface
(2018) Ločs, S.; Boiko, I.
The present research is dedicated to the study of influence of coaxial laser cladding (CLC) process parameters onto values of alloying compo nents 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 wit h 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 dur ing 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 tr ansverse 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 performe d. 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.
Lake blue clay - sapropel - flax shive briquettes for water absorption and desorption
(2018) Tretjakova, R.; Martinovs, A.; Avisane, M.; Kolcs, G.
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 reso urces. 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 co mparison 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.
Combustion property analyses with variable liquid marine fuels in combustion research unit
(2018) Hissa, M.; Niemi, S.; Sirviö, K.
The quality of ignition and co mbustion 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 a nd 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 existi ng 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 combus tion. 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 re sults 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 ig nition 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 us ed in a CI engine, the engine must be started and stopped with, e.g. LFO or MGO.
Kinematic viscosity studies for medium-speed CI engine fuel blends
(2018) Sirviö, K.; Niemi, S.; Help, R.; Heikkilä, S.; Hiltunen, E.
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 import ant 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 susta inable 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 kinema tic viscosity is needed to create proper fuel atomization. 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 t he 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 oi ls.

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