Volume 15 (2017)
  Number 4

Journal full text: Vol15No4

Contents


Pages

1441–1454 R. Abrahám, R. Majdan and R. Drlička
Comparison of tractor slip at three different driving wheels on grass
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Comparison of tractor slip at three different driving wheels on grass

R. Abrahám¹, R. Majdan¹ and R. Drlička²

¹Department of handling and transport machinery, Faculty of Engineering, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, SK949 76 Nitra, Slovak Republic
²Department of Quality and Engineering Technologies, Faculty of Engineering, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, SK949 76 Nitra, Slovak
*Correspondence: rudolf.abraham@uniag.sk

Abstract:

The paper deals with a possibility of tractor slip reduction on a grass and evaluates an use of two versions of special wheels. Both prototypes were developed at the Department of Transport and Handling of the Slovak University of Agriculture in Nitra. The first system was designed in 2010 year as blades wheels. The second system (spikes device) consists of spikes which are mounted onto standard tractor tyres with special cuts, was designed in 2014 year. The spikes are settled in these cuts while moving on road surface. The second one is placed near the drive wheels and uses the blades. The spikes and blades are ejected to reduce wheels slip when tractor operates on grass or soil. The base position allows tractor transport on road with standard tyres. The goal of experiments realized on grass surface was to compare mutually slip behaviour achieved. The measurements were realized with standard tyres without any modification, too. A tractor with three types of drive wheels were loaded by heavier tractor. Drawbar pull and wheel rotation speed for slip calculation were measured in tests. The results show a fact that a loss of energy due to the wheels slip increases, while a penetrometric resistance in the surface layers of a soil decreases, at soil humidity 33.2%. An application of both prototypes is very advantageous because they reduce the wheels slip, increase tractor operation efficiency and so protect the soil.

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1455–1462 A. Adamovics, S. Ivanovs and V. Bulgakov
Investigations about the impact of the sowing time and rate of the biomass yield and quality of industrial hemp
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Investigations about the impact of the sowing time and rate of the biomass yield and quality of industrial hemp

A. Adamovics¹, S. Ivanovs¹* and V. Bulgakov²

¹Latvia University of Agriculture, 2, Liela str., Jelgava LV-3001, Latvia
²National University of Life and Environmental Sciences of Ukraine, 15, Heroyiv Obrony str., Kyiv UK 03041, Ukraine
*Correspondence: semjons@apollo.lv

Abstract:

The aim of this study was to find the optimum sowing rate of industrial hemp (Cannabis sativa L.) and to clarify the impact of the sowing rate on the production of biofuel from hemp biomass in Latvia. Field trials were carried out at the Research and Study Farm ‘Pēterlauki’ of the Latvia University of Agriculture in 2012–2014. The industrial hemp (Cannabis sativa L.) ‘Futura 75’ was sown in a Luvic Endogleyic Stagnosol soil: pHKCl 6.7; P – 52 mg kg-1; K – 128 mg kg-1; the organic matter content – 21–25 g kg-1. Hemp was sown in 10-m2 plots, triplicate, on May 8 and 17. The total sowing rate was 20 (100), 30 (150), 40 (200), 50 (250), 60 (300), 70 (350), 80 (400), 90 (450), and 100 (500) kg ha-1 (germinating seeds per 1 m2). The plots were fertilised as follows: N – 120 kg ha-1; P2O5 – 80 kg ha-1; and K2O – 112 kg ha-1. Hemp was harvested when the first matured seeds appeared. The biometrical indices (height and stem diameter), harvesting time, the amount of fresh and dry biomass, and the fibre content were evaluated. Depending on the sowing rate, the yield of dry matter was on average 9.2–12.1 t ha-1 when hemp was sown at the beginning of May, and 7.9–10.0 t ha-1 when hemp was sown in the middle of May.

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1463–1473 S. Akdemir, C. Cavalaris, and T. Gemtos
Energy balance of sunflower production
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Energy balance of sunflower production

S. Akdemir¹*, C. Cavalaris², and T. Gemtos²

¹Namık Kemal University, Technical Sciences Vocational School, TR 59030 Tekirdag, Turkey
²University of Thessaly, Department of Agriculture Crop Production and Rural Environment, Volos, Greece
*Correspondence: sakdemir@nku.edu.tr

Abstract:

The aim of the present study was to make an energy analysis of sunflower crop in the Trakya Region of Turkey, to evaluate the potential for using it as bioenergy source. Actual data for the common cropping practices applied in the region were collected with questionnaires given to the farmers. Literature data were used to obtain necessary energy indices. The collected information was used to establish energy budgets. Two alternative scenarios were examined: 1st-Using only the seed for biofuel production and 2nd -using the seed for biofuel and the stalks as biomass for bioenergy. The results showed that sunflower presented positive energy balance for both cases. Net energy was 35,334 MJ ha-1 when only the seed was taken into account and 87,308 MJ ha-1 for both seed and stalks. Energy efficiency was 3.67 and 7.34 respectively. Fertilization was the most energy intensive input (6,594 MJ ha-1) accounting for 48–50% of the total inputs. Tillage was the second most energy intensive input (3,595 MJ ha-1) accounting for 26–27% of total inputs. There were 6 different tillage operations such as ploughing, 4 machinery passages for seedbed preparation and hoeing in the sunflower production. All these operations increased energy inputs of the tillage. The total energy inputs were relatively low because it was possible to achieve high yields without irrigation.

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1474–1483 A. Annuk, A. Allik and K. Annuk
Reed canary grass cultivation’s energy efficiency and fuel quality
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Reed canary grass cultivation’s energy efficiency and fuel quality

A. Annuk¹*, A. Allik¹ and K. Annuk²

¹University of Life Sciences, Institute of Technology, Department of Energy Engineering, Fr.R. Kreutzwaldi 56, EE51014 Tartu, Estonia
²Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences, Fr.R. Kreutzwaldi 5, EE51014 Tartu, Estonia
*Correspondence: andres.annuk@emu.ee

Abstract:

The article discusses the energy yield and yield capacity of reed canary grass stands in semi-natural and cultivated meadows with edaphic conditions most favourable for species growing on fertile soil. Energy grass production yields have been assessed with respect to the issues of precipitation, sunshine, and frozen ground. In Estonia, a dried matter level of 4.2–8.5 t ha-1 of reed canary grass may produce 72.91–147.56 GJ ha-1 gross energy by using 1.48–3.06 GJ ha-1 input energy, which consequently nets 71.44–1,445.00 GJ ha-1. The above finding indicates that 1 MJ input energy enables the production of 2.8 kg dry matter. The efficiency of energy production (ratio of energy returned on energy invested) depends on the amount of input energy used to grow and harvest reed canary grass. The input energy payback ratio for the given case was 48.2–49.4, which was higher than cases with lower and higher dry matter yield levels. Precipitation during the second part of the Estonian summer, heavy winter snow cover and a simultaneous frequent lack of frozen ground reduce the productivity of reed canary grass as energy hay because the winter or early spring harvest cannot be used.

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1484–1490 M. Barát, V. Rataj, Š. Týr, M. Macák and J. Galambošová
Effect of controlled traffic farming on weed occurrence
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Effect of controlled traffic farming on weed occurrence

M. Barát¹*, V. Rataj¹, Š. Týr², M. Macák¹ and J. Galambošová¹

¹Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Machines and Production Biosystems, Tr. Andreja Hlinku 2, SK94976 Nitra, Slovakia
²Slovak University of Agriculture in Nitra, Faculty of Agrobiology and Food Resources, Department of Sustainable Agriculture and Herbology, Tr. Andreja Hlinku 2, SK94976 Nitra, Slovakia
*Correspondence: xbarat@is.uniag.sk

Abstract:

Soil compaction caused by field traffic is one of the most important yield limiting factors. Moreover, published results report that soil over-compaction inhibits the uptake of plant nutrients and decreases their ability to compete with weeds. Controlled Traffic Farming (CTF) is technology which prevents excessive soil compaction and minimizes compacted area to the least possible area of permanent traffic lines. A long-term experiment was established at University farm in Kolinany (Slovakia) in 2010 with 6 m OutTrack CTF system. Random Traffic Farming (RTF) is simulated by 1 annual machinery pass crossing the permanent traffic lines. Aim of presented study was to assess the effect of CTF on weed infection pressure. To achieve this, weed occurrence at different traffic treatments was determined. Emerged weeds per square meter were counted, identified and recorded at 14 monitoring points. Results showed that higher weed infection was found at the area with one machinery pass compared to the non-compacted area. Following weeds were identified: Bromus secalinus L., Stellaria media (L.) VILL., Veronica persica POIR. in LAMK., Poa annua L., Polygonum aviculare L., Convolvulus arvensis L. Occurrence of these weeds could be used as soil compaction indicator. Based on these results it can be concluded, that CTF technology has potential to decrease weed infestation in comparison to RTF system due to ration of non-compacted to compacted area. Moreover, with exact localization of weeds in traffic lines together with exact identification of weed species, it is possible to target the application of herbicides.

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1491–1497 B. Bernardi, J. Tous, S. Benalia, L.M. Abenavoli, G. Zimbalatti, T. Stillitano and A.I. De Luca
The assessment of hazelnut mechanical harvesting productivity
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The assessment of hazelnut mechanical harvesting productivity

B. Bernardi¹, J. Tous², S. Benalia¹*, L.M. Abenavoli¹, G. Zimbalatti¹, T. Stillitano¹ and A.I. De Luca¹

¹University Mediterranea of Reggio Calabria, Department of Agraria, Feo di Vito IT89122 Reggio Calabria, Italy
²EMP Agrícola. Sant Antoni 26, ES43480 Vila-seca Tarragona, Spain
*Correspondence: soraya.benalia@unirc.it

Abstract:

Hazelnut cultivation represents a new opportunity for Calabrian mountainous and sloping areas (Southern Italy), where no alternative fruit crops, except forestry, could be settled. In this Region, hazelnut production doubled during the last fifty years, inciting the farmers to introduce mechanization in cropping practices such as harvesting in order to increase productivity and decrease production costs. Indeed, harvesting is currently one of the most expensive processes of the productive cycle, moreover to be time consuming if carried out manually. Mechanization degree depends significantly on the terrain topography: in sloping areas, rakes are often associated to aspirating machines to harvest the fallen fruit, while the employment of harvesting machines from the ground prevails in flat areas. In this context, the present paper aims to assess technical and economic aspects of harvesting operation, using a harvester from the ground model ‘Jolly 2800’ (GF s.r.l., Italy). Particularly, for technical purposes data about operational working time as well as working productivity were collected according to CIOSTA requirements, in two harvesting sites, whereas, for mechanical harvesting economic evaluation, an estimation model was applied to calculate machinery cost per hour. Moreover, the cost per kg of hazelnut in shell and the average cost per hectare were estimated also. The obtained results show a working productivity of 0.065 ha h-1 op-1 in the first harvesting site, while it was equal to 0.022 ha h-1 op-1 in the second one. Concerning the average cost per hectare, the second harvesting site showed the worst economic performances, with 550.76 € ha-1 against 182.54 € ha-1 obtained in the first one.

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1498-1516 V. Bulgakov, V. Adamchuk, M. Arak, I. Petrychenko and J. Olt
Theoretical research into the motion of combined fertilising and sowing tractor-implement unit
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Theoretical research into the motion of combined fertilising and sowing tractor-implement unit

V. Bulgakov¹, V. Adamchuk², M. Arak³, I. Petrychenko² and J. Olt³*

¹National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony Str., UA03041 Kyiv, Ukraine
²National Scientific Centre, Institute for Agricultural Engineering and Electrification, 11 Vokzalna Str., Glevaкha-1, Vasylkiv District, UA08631 Kiev Region, Ukraine
³Estonian University of Life Sciences, Institute of Technology, 56 Kreutzwaldi Str., EE51014 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

A mathematical model has been developed representing the motion of a seed drill combination simultaneously performing the preceding banded placement of mineral fertilisers. Such a combined unit comprises the gang-up wheeled tractor, the fertiliser distribution module behind the tractor attached to it with the use of a hitch and intended for the banded placement of mineral fertilisers and the grain drill behind the fertiliser distribution module attached to it also with the use of a hitch. For the components of this dynamic system the coordinates of their centres, their masses as well as the external forces and the reactions of the soil surface applied to them have been determined. In order to use the original dynamic equations in the form of the Lagrange equations of the second kind, the generalised coordinates and kinetic energy relations have been determined. Following the necessary transformations, a system of six differential equations of motion has been generated, which characterises the behaviour of the combined machine unit during its plane-parallel motion. In this system, two line coordinates and one angular coordinate characterise the behaviour of the propulsion and power unit (wheeled tractor), while three angular coordinates characterise the rotations of the draft gear and the centres of the machines integrated with its use.

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1517-1529 V. Bulgakov, V. Adamchuk, V. Nadykto, O. Kistechok and J. Olt
Theoretical research into the stability of motion of the ploughing tractor-implement unit operating on the ‘push-pull’ principle
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Theoretical research into the stability of motion of the ploughing tractor-implement unit operating on the ‘push-pull’ principle

V. Bulgakov¹, V. Adamchuk², V. Nadykto³, O. Kistechok³ and J. Olt⁴*

¹National University of Life and Environmental Sciences of Ukraine, 15, Heroyiv Oborony Str., UA 03041 Kyiv, Ukraine
²National Scientific Centre, Institute for Agricultural Engineering and Electrification, 11, Vokzalna Str., Glevaкha-1, Vasylkiv District, UA 08631 Kiev Region, Ukraine
³Tavria State Agrotechnological University, 18, B. Khmelnytsky Ave., UA 72312 Melitopol, Zaporozhye region, Ukraine
⁴Estonian University of Life Sciences, Institute of Technology, Kreutzwaldi 56, EE51014 Tartu, Estonia
*Correspondence: jyri.olt@emu.ee

Abstract:

The reduction of power consumption in the ploughing operations can be achieved by way of improving the grip properties of the implement-carrying tractors, which is facilitated by setting up ploughing units for operation on the ‘push-pull’ principle. The aim of the current research is to substantiate the set-up and parameters of the ploughing unit with a front-mounted plough basing on the theoretical investigation of the stability of its motion in the horizontal plane. The methods of research include obtaining the amplitude- and phase-frequency response characteristics of the dynamic system in order to analyse the stability of its motion under the action of external statistically random perturbations. Also, the methods of software development and PC-based numerical computation are applied. The results of the study prove that the increase of the ploughing unit’s travel speed results in the considerable rise of the gain of the amplitude of the tractor’s heading angle oscillation in response to the oscillation of the angular displacement of the front-mounted plough in the horizontal plane. The phase-frequency response displays the same behaviour, changing substantially together with the unit’s travel speed. Raising the coefficient of resistance to tyre slip of the tractor’s rear wheels from 100 to 130 kPa and the front wheels from 140 to 175 kPa results in a minor decrease of the amplitude of oscillation of the tractor’s heading angle φ. The ploughing unit has the best response to the input effect, i.e. the oscillation of the front-mounted plough’s angular displacement βp, when it operates using the 1+5 combination. The increase of the number of front-mounted plough bodies from 1 to 3 results in the substantial growth of the tractor’s heading angle oscillation amplitude. Taking into account the way, in which the ploughing unit as a dynamic system responds to the input perturbance, the increase of its travel speed can be restricted not by the condition of its motion stability, but solely by the agrotechnical requirements applied to such a process operation as ploughing. The ploughing unit’s motion stability substantially improves in case of higher air pressure in the tyres on the tractor’s front and rear wheels. This effect is especially pronounced in the perturbance oscillation frequency range (0…1.5 s–1) that covers the main part of its dispersion.

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1530–1539 J. Čedík, J. Chyba, M. Pexa and S. Petrásek
Influence of shape of cutting tool on pressure conditions in workspace of mulcher with vertical axis of rotation
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Influence of shape of cutting tool on pressure conditions in workspace of mulcher with vertical axis of rotation

J. Čedík¹*, J. Chyba², M. Pexa¹ and S. Petrásek²

¹Czech University of Life Sciences, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ16521, Prague 6, Czech Republic
²Czech University of Life Sciences, Faculty of Engineering, Department of Agricultural Machines, Kamýcká 129, CZ16521, Prague 6, Czech Republic
*Correspondence: cedikj@tf.czu.cz

Abstract:

Nowadays there is laid great insistence on work efficiency improvement. This effort also affects the construction of mowers such as mulchers. Mulching with a vertical axis of rotation is very energy demanding work operation mainly, due to high energy losses. These energy losses, but also the quality of work, are influenced by the airflow and associated conditions of pressure inside the workspace of mulcher. Airflow in the workspace ensures repetitious contact of the truncated forage crops with the cutting edge tool and thus ensures crushing of aboveground parts of plants. The paper deals with the influence of the cutting tool shape on the mulcher’s inside workspace pressure conditions with the vertical axis of rotation. The influence of the trailing edge angle and rake angle on the pressure profile in the mulcher’s workspace with dependence on the rotor speed was examined. Measurements were performed on a laboratory single rotor mulcher model. It was found that in the mulcher’s workspace the vacuum is formed by virtue of the rotary movement of the cutting tools wherein the vacuum increases with rotor speed. The maximum measured vacuum was about 2.4 kPa and from the centre of the rotor towards its circumference almost linearly decreases. Furthermore, it was found that with decreasing trailing edge angle and with increasing rake angle the maximum vacuum decreases. When reducing the angle of the trailing edge from 45° to 25° led to reduction of vacuum of about 0.3 kPa (12.6%).

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1540–1549 J. Čedík, M. Pexa and R. Pražan
Effect of rake angle and cutting speed on energy demands of mulcher with vertical axis of rotation
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Effect of rake angle and cutting speed on energy demands of mulcher with vertical axis of rotation

J. Čedík¹*, M. Pexa¹ 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 contribution deals with the reduction of agriculture energy demands. For maintenance and treatment of permanent grassland areas, areas left fallow and put to rest the mulching in combination with other workflows (mowing, grazing) is advantageous procedure. As conventional impact grass cutting and chopping is energy demanding procedure, it is proper to reduce the energy demands of such device. In the paper the effect of shape of cutting tool, particularly the rake angle, on energy demands of mulcher with vertical axis of rotation is studied. The effect of cutting speed on energy demands is also verified. The measurement was performed using mulcher MZ 6000 made by Bednar FMT Ltd. with working width of 6 m and three rotors. During the measurement the test rides using the cutting tools with different rake angle and cutting speeds of 105m s-1, 89 m s-1 and 79 m s-1 were performed. The rake angle of cutting tools were chosen 0°, 15° and 25°. The test area was pasture with permanent grassland. During the measurement the torque and power, transferred through PTO to the machine, fuel consumption and GPS coordinates were measured. From each test ride the samples of grass matter were taken in order to determine the yield and moisture content. It was found that increase of the rake angle up to 25° and decrease of the cutting speed resulted in decrease of the power requirement of the mulcher.

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1550–1558 L. Chladek, V. Plachy, P. Vaculik and P. Brany
Evaluation of nutritional and physical values of pellets based on pea and lupine with added yeast in chickens fattening
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Evaluation of nutritional and physical values of pellets based on pea and lupine with added yeast in chickens fattening

L. Chladek¹*, V. Plachy², P. Vaculik¹ and P. Brany¹

¹Czech University of Life Sciences Prague (CULS), Faculty of Engineering, Kamýcká 129, CZ165 21 Prague - Suchdol, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Microbiology, Nutrition and Dietetics, Kamýcká 129, CZ165 21 Prague - Suchdol, Czech Republic
*Correspondence: chladekl@tf.czu.cz

Abstract:

The article is focused on the development of the new type of broiler chicken feed, based on pea (Pisum sativum L.) and blue lupine (Lupinus angustifolius L), enriched with used dried brewer´s yeast. This composition eliminates use of soybean meal (PES) that was yet a traditional component in chicken feed. The main reason for its elimination was the using of genetically modified varieties of soybean and its relatively high price around 0.5 €uro kg-1 in Czech Republic. For milling of pea or blue lupine was used vertical (hammer) mill type Taurus, supplied by company TAURUS, for drying of used brewer´s yeast had been used drier Memmert UFE 800, final dry matter of the yeast was 88%. For pellets production were used two devices, press type JGE 120-6110 and Testmer. For the determination of physical properties of manufactured pellets (the weight of 1,000 pieces, bulk density, abrasiveness and pellet durability index PDI) were used following laboratory devices, Pellet Tester Holmen NHP and Testmer 200. Experimental activities had shown that the best results were reached using pellets manufactured on base blue lupine enriched by dried brewer´s yeast (6%).

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1559–1570 O. Chotovinský and V. Altmann
Performance analysis of biodegradable municipal solid waste collection in the Czech Republic
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Performance analysis of biodegradable municipal solid waste collection in the Czech Republic

O. Chotovinský* and V. Altmann

Department of Machinery Utilization, 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 article deals with the issues of biodegradable municipal solid waste management system, focusing on its separate collection. The two basic locations are compared – rural area and urban area. The emphasis is put on evaluation of individual biodegradable municipal solid waste collections development from 2012 to 2015. Individual technological performances of collection are also observed and evaluated (e.g. biodegradable municipal solid waste production, development of container quantity and collection frequency). The observed data also verify the efficiency of biodegradable municipal solid waste management compared to relative representation of this waste in rest municipal solid waste, which is produced in both locations. Also referential locations without separate biodegradable municipal solid waste collection are observed for evaluation. There are one locality of an urban area and one rural area too. The decrease of biodegradable municipal solid waste in rest of municipal solid waste at the basic rural researched area indicates that the directive on landfills could be followed with well-chosen technological parameters of separate biodegradable municipal solid waste collection at a given site. A statistically significant impact of separate biodegradable municipal solid waste production on relative amount of the biodegradable part in rest municipal solid waste has been demonstrated at the side of this basic rural area.

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1571–1581 J. Ereline, K. Pärenson, D. Vahtrik, M. Pääsuke and H. Gapeyeva
Skeletal muscle tone and motor performance characteristics in dentists as compared to controls
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Skeletal muscle tone and motor performance characteristics in dentists as compared to controls

J. Ereline¹*, K. Pärenson², D. Vahtrik¹, M. Pääsuke¹ and H. Gapeyeva¹

1University of Tartu, Faculty of Medicine, Institute of Sport Sciences and Physiotherapy, 5 Jakobi Street, EE51014 Tartu, Estonia
²Selfdiagnostics GmbH OÜ, Rävala pst 3/Kuke 2, EE10143 Tallinn, Estonia
*Correspondence: jaan.ereline@ut.ee

Abstract:

The daily work tasks of dentists are associated with repeated movements and static load during the treatment of patients. Dentists’ profession includes manual dexterity and maintaining the occupational posture for a long time. Previously it has been noted that dentists have increased muscle stress in neck, shoulder and lower back regions. The aim of the present study was to compare the muscle tone and motor performance characteristics of neck and shoulder region in dentists and representatives of other professions who do not have similar static load of long-time duration (as controls). Twenty women aged 34–55 years participated in the study: ten dentists with the age (mean and SE) of 40.2 ± 3.9 years and ten controls (bookkeepers, security guards, office workers, printing house workers, laundry and dry cleaning workers) with the age of 40.9 ± 2.4 years; working period was on the average 14 years in both groups. The tone characteristics of m. trapezius and m. extensor carpi radialis were investigated by device Myoton-2 (Müomeetria Ltd, Estonia) at rest and at maximal voluntary contraction (MVC) in sitting position at the workplace of participants. The cervical range of motion (CROM) and the handgrip strength were measured. Significantly higher (P < 0.05) tone and elasticity characteristics of m. extensor carpi radialis and lower (P < 0.05) tone and elasticity characteristics of m. trapezius at rest were noted in dentists compared to controls. At MVC, no significant differences were found in the studied characteristics between body sides in the measured groups. Dentists had lower (P < 0.05) CROM of flexion and rotation than controls. In dentists emerged significant difference in muscle elasticity characteristics for the right body side, this is related with stretching for dentistry instruments.

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1582–1601 M. Gailis, J. Rudzitis, J. Kreicbergs and G. Zalcmanis
Experimental analysis of hydrotreated vegetable oil (HVO) and commercial diesel fuel blend characteristics using modified CFR engine
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Experimental analysis of hydrotreated vegetable oil (HVO) and commercial diesel fuel blend characteristics using modified CFR engine

M. Gailis¹²*, J. Rudzitis¹, J. Kreicbergs¹ and G. Zalcmanis¹

¹Riga Technical University, Faculty of Mechanical Engineering, Transport and Aeronautics, Department of Automotive Engineering, Viskalu 36A, LV1006 Riga, Latvia
²Latvia University of Agriculture, Faculty of Engineering, Department of Mechanics, Liela street 2, LV 3001, Jelgava, Latvia
*Correspondence: maris.gailis@rtu.lv

Abstract:

Performance parameters of different commercial diesel fuels is a subject of interest for fuel consumers. Fuel retailer Neste recently introduced a new brand of WWFC 5th grade diesel fuel in Baltic market, consisting of diesel fuel and hydrotreated vegetable oil (HVO) blend. Fuel samples have been recently tested on chassis dynamometer, measuring wheel power and torque and in road conditions, measuring fuel consumption. Evaluation of fuel consumption and performance parameters in road or laboratory conditions may yield uncertain results due to complexity of modern automobile engine management and emission reduction systems. To better evaluate the combustion, fuel samples have been tested in modified CFR engine at various intake air pressure, temperature and compression ratio settings. Engine indicated performance parameters and combustion phasing of regular diesel fuel and diesel fuel-HVO blend are presented. Comparing to regular diesel fuel, fuel blend with HVO showed reduced apparent heat release rate (AHRR) during premixed combustion phase at low inlet air temperature and low compression ratio conditions, comparing to regular diesel fuel. Premixed combustion phase AHRR of diesel-HVO blend increased above AHRR of regular diesel fuel at higher inlet air temperature and higher compression ratio conditions. Diffusion controlled combustion phase AHRR of diesel-HVO blend increased above AHRR of regular diesel fuel at higher inlet air temperature, higher compression ratio conditions and supercharged air supply.

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1602–1612 G. Hrenov, I. Vilcane, V. Urbane and P. Tint
Improving job satisfaction with different intervention methods among the school personnel in Estonia and Latvia
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Improving job satisfaction with different intervention methods among the school personnel in Estonia and Latvia

G. Hrenov¹, I. Vilcane², V. Urbane² and P. Tint¹*

¹Tallinn University of Technology, Faculty of Economics, Institute of Business Administration, Ehitajate 5, EE19086, Tallinn, Estonia
²Riga Technical University, Faculty of Engineering Economics and Management, Institute of Labour Safety and Civil Defence, Kalku street 1, LV-1658, Riga, Latvia
*Correspondence: piia.tint@ttu.ee

Abstract:

This investigation was carried out in two high schools: one in Estonia (EST1) and one in Latvia (LAT1). The offices EST2 and LAT2 were chosen from the countryside of the both countries. Office EST1 is situated in an atrium-type building for educational and research needs. The second building is mainly for education (auditoriums) and the offices LAT1 are situated on the ground floor. The third and the fourth offices were taken for comparison. Office EST2 is situated in a countryside in an old wooden building; the fourth office LAT2 is located in a new building in Latvian countryside. All together 181 office-workers were involved. At first, the work environment conditions were measured. The ergonomics of workplaces was assessed with ART-tool and Kiva-questionnaire was used to study psychosocial conditions and job satisfaction at computer-equipped workplaces. Occupational hazards were measured to clarify, do the work environment influence on the behaviour and the job motivation and satisfaction of the worker at workplace? After the first questioning of workers using Kiva-questionnaire, the Metal Age programme was implemented and after the intervention, the Kiva-questionnaire was carried out again. The results showed that if the preventive measures for solving the problems at workplace are implemented, and the employers and the employees are trained and consulted using the appropriate programmes, the stress situations could be avoided. The workers in all offices were confident that the discussion about the problems is very important as the work with computers is intensive and there is a very short time to communicate with each other. The educational work is also stressful.

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1613–1620 J. Hůla, M. Kroulík and I. Honzík
Critical velocity of solid mineral fertilizers in a vertical upward airstream and repose angle
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Critical velocity of solid mineral fertilizers in a vertical upward airstream and repose angle

J. Hůla*, M. Kroulík and I. Honzík

Czech University of Life Sciences Prague, Faculty of Engineering, Kamýcká 129, CZ165 21 Prague 6 – Suchdol, Czech Republic
*Correspondence: hula@tf.czu.cz

Abstract:

Critical velocity of mineral fertilizers in airstream is important not only at the application of fertilizers by spreaders but also at combine of fertilizing and sowing. The knowledge of angles of repose is important to design hoppers on spreaders for solid mineral fertilizers. Critical velocities for six solid mineral fertilizers were measured in the vertical aspiration duct of a laboratory sorting machine. Variation curves were constructed for particular fertilizers and the mean critical velocity of fertilizers (velocity of uplift) was computed. The mean critical velocity of fertilizers was between 8.53 and 12.43 m s-1. The lowest critical velocity was found out in the fertilizer UREA 46%, the highest in the fertilizer LAV. Statistical significance of differences in the critical velocity of fertilizers was assessed. Angles of repose of eight solid mineral fertilizers were also measured and statistical significance of differences was evaluated. The highest values of repose angle were determined for potassium salt and ammonium sulfate (35.9° respectively 34.9°), the lowest values for UREA and LAV (28.7° respectively 29.6°). The obtained results extend information applicable to an assessment of parameters of the operation quality of spreaders during mineral fertilizer application.

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1621–1628 Y. Katsiagiannis, A. Annuk and E.S. Karapidakis
Contribution of pumped hydro energy storage for more RES utilization on autonomous power systems
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Contribution of pumped hydro energy storage for more RES utilization on autonomous power systems

Y. Katsiagiannis¹, A. Annuk² and E.S. Karapidakis¹*

¹Technological Educational Institute of Crete, Faculty of Applied Science, Department of Electrical Engineering, Estavromenos Campus, GR71004 Heraklio, Greece
²Estonian University of Life Sciences, Institute of Technology, Department of Energy Engineering, 56 Kreutzwaldi Str., EE51014 Tartu, Estonia
*Correspondence: karapidakis@staff.teicrete.gr

Abstract:

This paper addresses the performance issues of autonomous power systems under high renewable energy sources (RES) penetration. Renewable energy sources could be the main option for isolated power generation at remote locations in case that energy storage introduced. At the moment, pumped hydro storage (PHS) units and batteries storage systems (BSS) represent the most mature technologies for large scale energy storage. The basic criteria for this kind of energy storage unit installations include, (a) the existence of an autonomous power system with local power stations, (b) the high electricity production cost, (c) the potential of renewable energy sources (mainly wind and solar), and (d) the non-flat terrain morphology (for PHS). Greek islands represent ideal cases for large scale energy storage installations, as they fulfil all the above criteria. This paper shows the effect of the installation of a planned PHS unit in Crete island. The calculations are based on real data provided by the Cretan power system operator, whereas the results show the effect of energy storage units operation on the energy mix, as well as the economic viability of the project, which is combined with significant environmental benefits.

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1629–1635 S. Kovář, J. Mašek and P. Novák
Comparison of tillage systems in terms of water infiltration into the soil during the autumn season
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Comparison of tillage systems in terms of water infiltration into the soil during the autumn season

S. Kovář*, J. Mašek and P. Novák

Czech University of Life Sciences Prague, Faculty of Engineering, Kamycka 129, CZ165 21 Prague 6 – Suchdol, Czech Republic
*Correspondence: kovars@tf.czu.cz

Abstract:

The soil belongs to the most valuable parts of the planet Earth. It is, endangered by water erosion, which causes huge destruction every year, or damage to farmland. More than half of the agricultural land in the Czech Republic is threatened by water erosion. The measurement was performed in the location Nesperská Lhota. The trial has been established on loamy sand Cambisol. In the field experiment, there were created 6 different variants which wad differed by soil tillage and crop. In the individual variants maize and oats were located. The field trial has been existing for a long time, as it was founded in 2009. Two measuring methods of water infiltration were used for the measurements: a mini disk infiltrometer and a single ring. The measurement was performed in the period of September 2016 before the harvest of maize. The soil aggregates were already stabilized at that time after all tillage operations. The measurement result showed the difference between the methods of soil tillage. The greatest ability of infiltration had a variant of maize with inter-row oats. Surprisingly, it was followed by maize, which was processed by ploughing technology. The lowest infiltration capacity was showed by oats reduced by soil tillage. A variant without vegetation had the second lowest infiltration. Our results obtained at rate of water infiltration into the soil affirm the need to control measures in the late vegetative stages. It is important for most of the rainfall to be quickly infiltrated so that it prevents the formation of massive surface runoff.

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1636–1645 K. Křížová and J. Kumhálová
Comparison of selected remote sensing sensors for crop yield variability estimation
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Comparison of selected remote sensing sensors for crop yield variability estimation

K. Křížová¹* and J. Kumhálová²

¹Czech University of Life Sciences in Prague, Faculty of Engineering, Department of Agricultural Machines, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Czech University of Life Sciences in Prague, Faculty of Engineering, Department of Machinery Utilization, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: krizovak@tf.czu.cz

Abstract:

Currently, spectral indices are very common tool how to describe various characteristics of vegetation. In fact, these are mathematical operations which are calculated using specific bands of electromagnetic spectrum. Nevertheless, remote sensing sensors can differ due to the variations in bandwidth of the particular spectral channels. Therefore, the main aim of this study is to compare selected sensors in terms of their capability to predict crop yield by NDVI utilization. The experiment was performed at two locations (Prague-Ruzyně and Vendolí) in the year 2015 for both locations and in 2007 for Prague-Ruzyně only, when winter barley or spring barley grew on the plots. The cloud-free satellite images were chosen and normalised difference vegetation indices (NDVI) were calculated for each image. Landsat satellite images with moderate spatial resolution (30 m per pixel) were chosen during the crop growth for selected years. The other data sources were commercial satellite images with very high spatial resolution – QuickBird (QB) (0.6 m per pixel) in 2007 and WorldView-2 (WV-2) (2 m per pixel) in 2015 for Prague-Ruzyně location; and SPOT-7 (6 m per pixel) satellite image in 2015 for Vendolí location. GreenSeeker handheld crop sensor (GS) was used for collecting NDVI data for both locations in 2015 only. NDVI calculated at each of images was compared with the yield data. The data sources were compared with each other at the same term of crop growth stage. The results showed that correlation between GS and yield was relatively weak at Ruzyně. Conversely, significant relation was found at Vendolí location. The satellite images showed stronger relation with yield than GS. Landsat satellite images had higher values of correlation coefficient (in 30 m spatial resolution) at Ruzyně in both selected years. However, at Vendolí location, SPOT-7 satellite image has significantly better results compared to Landsat image. It is necessary to do more research to define which sensor measurements are most useful for selected applications in agriculture management.

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1646–1658 S. Lamptey, S. Yeboah L. Li and R. Zhang
Dry matter accumulation and nitrogen concentration in forage and grain maize in dryland areas under different soil amendments
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Dry matter accumulation and nitrogen concentration in forage and grain maize in dryland areas under different soil amendments

S. Lamptey¹²⁴*, S. Yeboah¹³⁵ L. Li¹² and R. Zhang¹³

¹Gansu Provincial Key Lab of Arid Land Crop Science, Lanzhou CN730070, China
²College of Agronomy, Gansu Agricultural University, Lanzhou CN730070, China
³College of Resources and Environmental Sciences, Gansu Agricultural University, Lanzhou CN730070, China
⁴University for Development Studies, P.O Box TL 1882, Tamale–Ghana
⁵CSIR–Crops Research Institute, P.O Box 3785, Kumasi, Ghana
*Correspondence: naalamp2009@yahoo.com

Abstract:

Soil amendment plays significant role in improving soil fertility and increasing crop productivity in rain–fed agriculture. Understanding the grain yield associated with dry matter and N concentration is essential for improving maize production. A 3– year field study was conducted to determine dry matter accumulation, nitrogen concentration and grain yield of forage and grain maize under different soil amendments in the Western Loess Plateau of China. The experiment was conducted using a randomized complete block design with four treatments and three replicates per treatment. Results showed that dry matter accumulation and nitrogen concentration in the swine manure in combination with chemical fertilized (SC) crops was significantly higher (by ≈ 60% and 39%) than no amendment (NA) which therefore translated into increased grain yield ≈ 74%. The SC treatment also improved leaf area index and chlorophyll content (P < 0.05) by approximately 34% to 32% compared to NA, which supported the above results. The nitrogen concentration in the leaf was higher at jointing and lower at maturity. Grain yield positively correlated with dry matter accumulation and nitrogen concentration at jointing, flowering and milk stage. Dry matter accumulation and grain yield also increased in the sole swine manure (SM) and maize stover (MS) treatments, but to lesser extent than SC. Based on the improvement of dry matter accumulation, nitrogen concentration and grain yield, swine manure in combination with chemical fertilizer appears to be a better fertilization option under dryland cropping systems.

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1659–1673 S. Locs, I. Boiko, P. Drozdovs, J. Dovoreckis and O. Devoyno
Investigation of coaxial laser cladding process parameters influence onto single pass clad geometry of tool steel
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Investigation of coaxial laser cladding process parameters influence onto single pass clad geometry of tool steel

S. Locs¹², I. Boiko¹*, P. Drozdovs², J. Dovoreckis² and O. Devoyno³

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
³National Technical University, Faculty of Mechanical Engineering B.Khmelnitsky street 9-6, 220013 Minsk, Belarus
*Correspondence: irina.boiko@rtu.lv

Abstract:

This paper is devoted to the investigation of the influence of technological parameters on the single pass clad geometry and quality as well as elemental composition in the clad after coaxial laser cladding (CLC). The objects of the investigation are components of expensive machines and tools for presswork needed to be repaired, i.e. refurbished for the future application with the goal of effective using of material resources in production. Nowadays such repair of worn tools is an actual task due to tendency for thrifty management of resources at affordable cost. Experimental work was carried out using CLC system, which consists of industrial robot and a ytterbium fiber laser with a core diameter of 100 μm, integrated to the coaxial powder supplying cladding head. During research separate cladding tracks of metal powder AISI М2 (particle size 53–150 μm) were deposited on the top surface of steel plates, which were ground before treatment. This work’s highlighted parameters for variation were laser scanning speed and laser beam focus plane distance. The clad geometry was examined on cross-sections with SEM. Elemental composition was determined by the X-ray spectroscopy analysis. Gladding beads with good surface quality were achieved. Cross-sectional observation presented that clads has a good fusion with the base material without exfoliation. Keyhole shape of molten substrate area was achieved, which leads to increase of the dilution value. The future research is needed to achieve stable quality of cladding, which is extremely necessary for industry.

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1674–1685 J. Maga and K. Krištof
Effect of drill machine operating speed on quality of sowing and biomass yield
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Effect of drill machine operating speed on quality of sowing and biomass yield

J. Maga and K. Krištof*

University of Agriculture in Nitra, Faculty of Engineering, Department of Machines and Production Biosystems, Tr. A. Hlinku 2, SK949 76 Nitra, Slovakia
*Correspondence: koloman.kristof@uniag.sk

Abstract:

The paper is focused on the study and evaluation of quality of the seeding of seeds and its effect on the biomass yield. The aim was to evaluate the space arrangement of the seeds by using of polygon method on one field with the repetition for different forward speeds of the drill machine. For the evaluation there were used digital photographs, which were taken during repeated measurements of the each value of the forward speed after sprouting of crop. These images have been used in order to determine the shape and size of the surface area belonging to the plant. Own software TfPolyM was used for the image analysis. The shape of the polygons belonging to the individual plants was expressed by values of the shape factor Tf. This factor characterises the suitability the shape of polygon surface related to the individual plant. By comparing of the values of the shape factors for different forward speeds of the drill machine we can determine the optimal value of the forward speed from the point of seed placement uniformity in horizontal level. During harvest of the crop there was analysed the variability of the biomass yield in relation to values of the forward speed used during seeding. The most suitable values of shape factor Tf (0.8519) was recorded for speed of drill machine set on 12 km h-1. For other tested speeds 8, 10, 15 km h-1 were recorded lower values of shape factor 0.7994, 0.8173 and 0.8449, respectively. In determination of biomass production for drill machine speed 12 km h-1 the greatest yield from 1 m2 was observed. Subsequently, for speeds 8 and 10 km h-1 was lower about 4.26% and 1.83%, respectively. For tested speeds of drill machinery 15 km h-1 and above was observed only a small descent of yields about 0.6%. Fluctuation in yields affected by working speed then demonstrates fluctuation in sowing rate. It was also observed that the working speed of sowing machinery also affect the amount of yield directly. However, in case of lowest yield of straw recorded it was observed even 20% decrease in yield of grains.

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1686–1692 N. Mazitova, N. Simonova, E. Adeninskaya and M. Trofimova
Occupational diseases among agricultural workers in the Russian Federation: review of statistical data
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Occupational diseases among agricultural workers in the Russian Federation: review of statistical data

N. Mazitova¹*, N. Simonova², E. Adeninskaya³ and M. Trofimova⁴

¹Research and Clinical Center of Otorhinolaryngology of Federal medical and biological agency, Department of Occupational diseases, Volokolamskoye hgw., 30, build. 2, RU 123182 Moscow, Russia
²Klinsky Institute of occupational safety and working conditions,Department for Science, Berezovoy roschi str., 4, RU125252 Moscow, Russia
³Central Clinical Hospital of Civil Aviation, Department of Occupational Health, Ivankovskoye hgw., 7, RU125367 Moscow, Russia
⁴Administration of the Federal Service for Supervision of Consumer Rights Protection and Human Welfare in the Republic of Tatarstan, B.Krasnaya str., 30, RU420111 Kazan, Russia
*Correspondence: mazitova@otolar-centre.ru

Abstract:

The aim of the study is to analyze the epidemiological situation of occupational diseases among agricultural workers in Russia. To address this task, the analysis of occupational diseases incidence was carried out.
Conclusions. For the last decades the proportion of rural working population in Russia is gradually decreasing, but remains noticeably higher than in other industrialized countries. There is a huge difference between entities of the Russian Federation in occupational illnesses incidence rates among agriculture workers, which can be explained by: (a) the distinction of health care availability; (b) lack of occupational physicians in rural areas; (c) the high level of the incidence of non-communicable diseases, which can disguise occupational illnesses among agricultural workers. The improvement of the health care regulatory legal framework, development of evidence-based clinical practice guidelines, quality improvement in postgraduate education of medical doctors in rural areas, increasing in the number of occupational health physicians in rural areas, and implementation of long-term health promotion programs are necessary in order to maintain the heath of agricultural workers in the Russian Federation. This list of priority measures is not sufficient, as it highlights only the main issues in the field of occupational health.

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1693–1699 H. Meripõld, U. Tamm, S. Tamm, T. Võsa and L. Edesi
Fodder galega (Galega orientalis Lam) grass potential as a forage and bioenergy crop
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Fodder galega (Galega orientalis Lam) grass potential as a forage and bioenergy crop

H. Meripõld*, U. Tamm, S. Tamm, T. Võsa and L. Edesi

Estonian Crop Research Institute, EE-48309 Jõgeva, Estonia
*Corresponding author: heli.meripold@etki.ee

Abstract:

Fodder galega (Galega orientalis Lam.) is a forage legume that has been grown in Estonia for almost forty five years. Pure galega is known to be persistent, high-yielding crop and rich in nutrients, in particular crude protein (CP), neutral detergent fibre (NDF) and acid detergent fibre (ADF). Galega is usually grown in a mixture with grass in order to optimize its nutrient concentration, increase dry matter (DM) yield and improve fermentation properties. The trial plots were established on a typical soddy-calcareous soil. There are certain grass species suitable for the mixture. In this study galega mixtures with reed canary grass cv. ‘Marathon’, timothy cv. ‘Tika’, red fescue cv. ‘Kauni’ and festulolium cv. ‘Hykor’ were under investigation in three successive years (2013–2015). In order to increase competitiveness of grasses and the yield of the first cut, two N fertilization levels were used: N0 and N50 kg ha-1. Two cuts were carried out during the growing season in all three years. The total dry matter yield varied from 9.1 to 12.8 t ha-1. The NDF concentration in the DM varied from 495−559 g kg-1. Both DM-yield and NDF were dependent on the year, mixture, cutting time and fertilization. Nitrogen fertilization (N50 kg ha-1) favoured grass growth and reduced the role of galega in the sward.

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1700–1707 M. Mimra and M. Kavka
Risk analysis regarding a minimum annual utilization of combine harvesters in agricultural companies
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Risk analysis regarding a minimum annual utilization of combine harvesters in agricultural companies

M. Mimra* and M. Kavka

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

Abstract:

This article presents the results of entrepreneurial risk analysis concerning a minimum annual utilization of harvesters in a company providing agricultural services where a group of combine harvesters is used. Furthermore, this article presents the following analysed key operating parameters with the greatest influence on reaching the minimum annual utilization and performance: the changing market price of mechanized work, the volatile purchase price of the machines, average maintenance costs).
Partial profit which an enterprise can reach through operating combine harvesters is directly affected by the level of their annual utilization. Not reaching the minimum annual utilization of combine harvesters would create losses that could result in termination of business activity in the specific field or even insolvency of the company. It is therefore necessary to monitor the key factors which influence the minimum annual usage and in case of negative developments to take timely corrective actions.

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1708–1715 A. Muntean, T. Ivanova, P. Hutla and B. Havrland
Influence of raw material properties on the quality of solid biofuel and energy consumption in briquetting process
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Influence of raw material properties on the quality of solid biofuel and energy consumption in briquetting process

A. Muntean¹, T. Ivanova¹*, P. Hutla² and B. Havrland¹

¹Czech University of Life Sciences, Faculty of Tropical AgriSciences, Department of
Sustainable Technologies, Kamýcká 129, CZ 16500 Prague, Czech Republic
²Research Institute of Agricultural Engineering, Drnovská 507, CZ 16101 Prague,
Czech Republic
*Correspondence: ivanova@ftz.czu.cz

Abstract:

The present paper is related to a pressing process research of raw materials with different density in order to investigate impact of biomass density on a formation of monolithic structure and the briquette’s strength. Another focus of the study is an influence of raw materials particles’ size on agglomeration process and quality of final product. Different biomass materials like two varieties of miscanthus, industrial hemp and apple wood were selected for experimental purposes of this research. Mechanical durability which represents one the main indicator of briquettes’ mechanical quality (strength) was determined. The research was conducted using hydraulic piston briquetting press. For assessment of briquetting efficiency during the whole process energy consumption was measured. One of the most important factors that can affect briquetting process is the temperature of pressing chamber which was registered as well. The main goal of the research was practical study of possibilities for increasing production efficiency and quality of briquettes on hydraulic piston briquetting press with respect to optimization of particles’ size of raw materials and use of raw materials the most appropriate density.

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1716–1724 V. Novák, D. Novák J. Volf and V. Ryzhenko
Verification of mathematical model of pressure distribution in artificial knee joint
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Verification of mathematical model of pressure distribution in artificial knee joint

V. Novák¹, D. Novák² J. Volf¹ and V. Ryzhenko¹*

¹University of Life Sciences Prague, Faculty of Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Matej Bel University, Faculty of Natural Sciences, Department of Technology, Tajovského 40, SK974 01 Banská Bystrica, Slovakia
*Correspondence: volf@tf.czu.cz

Abstract:

The paper deals with pressure distribution measurement in knee arthroplasty, which is an artificial replacement of human knee joint. The scope of the article is to verify the accuracy of a mathematical model by real measurements. The calculated pressure values basing on the mathematical model are compared with actually measured pressure values in the contact area of the joint. Hereby maximal load the in the contact area, the distribution of the pressure and any potentially dangerous pressure deviations during the walk cycle are checked. To enable accurate pressure distribution measurement without interfering into human’s body, a sophisticated measuring setup was created: the contact area of the joint was equipped with several pressure sensors and a machine simulating the human walk cycle was used. The measured pressure data are finally compared with those from the mathematical model and with the strength limit of the used material, to verify the accuracy of the mathematical model experimentally.

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1725–1732 M. Olle
The yield, height and content of protein of field peas (Pisum sativum L.) in Estonian agro-climatic conditions
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The yield, height and content of protein of field peas (Pisum sativum L.) in Estonian agro-climatic conditions

M. Olle

Estonian Crop Research Institute, Department of Plant Breeding, J. Aamissepa 1, EE48309 Jogeva alevik, Estonia
Correspondence: margit.olle@etki.ee

Abstract:

Pisum sativum L. is important protein crop in the world. The purpose of this investigation was to see whether pea varieties differ in their yield, height and content of protein. Another aim was to select the best varieties suitable for production. Field experiments with different varieties of peas (‘Bruno’, ‘Capella’, ‘Clara’ and ‘Vitra’) were carried out at the Estonian Crop Research Institute in 2014 and in 2015. Yields (t ha-1) in 2014 and 2015 did not differ much, while yield from variety ‘Bruno’ was very different between years 2014 and 2015 and was much higher in 2015. The most suitable height of field peas is in a range of 60…100 cm, because the plants with such a height are most effectively suppressing weeds. It can be concluded that varieties with suitable height in our investigation were: ‘Bruno’, ‘Capella’ and ‘Clara’. Variety ‘Vitra’ was too high, is lodging easily and is therefore hard to harvest. Crude protein content (% in dry matter) was lowest in ‘Clara’; all other varieties had a higher content of protein, within much the same range. Based on the results of present investigation it can be concluded that out of those four varieties the most suitable varieties for production are ‘Bruno’ and ‘Capella’. Choice of the right variety for pea cultivation is very important, but depends on the local agro-climatic conditions. As in Baltic – Nordic countries and in north of America the agro-climatic conditions are more or less similar the results are useful for those countries.

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1733–1742 M. Pexa, J. Čedík, F. Kumhála and R. Pražan
Comparison of mechanical and electric drive of mulcher
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Comparison of mechanical and electric drive of mulcher

M. Pexa¹*, J. Čedík¹, F. Kumhála² and R. Pražan³

¹Czech University of Life Sciences, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ16521, Prague 6, Czech Republic
²Czech University of Life Sciences, Faculty of Engineering, Department of Agricultural Machines, Kamýcká 129, CZ16521, Prague 6, Czech Republic
³Research Institute of Agriculture Engineering, Drnovská 507, CZ161 01, Prague 6, Czech Republic
*Correspondence: pexa@tf.czu.cz

Abstract:

The contribution is focused on comparison of mechanical and electric drive of mulcher with vertical axis of rotation by means of mathematical model. The mulcher has working width of 6 m and it is usually aggregated with tractor of minimal power of 150 kW. On the test plot the torque and power transferred trough the tractor PTO, fuel consumption and the production of gaseous emissions components were monitored. This field measurement served as a basis for modelling as well as measured complete characteristics of the combustion engine of the tractor John Deere 7930. As a main base for the modelling the record of real operation of the tractor with mulcher was used. Then, in the software product MathCad the operation of the tractor with mechanical and electrical drive of the mulcher was modelled. In the case of the electrical drive of the mulcher the tractor with internal combustion engine, connected to generator was taken into consideration. Due to overall lower efficiency of the electrical drive with generator, worse values of the fuel consumption and emissions production in comparison with mechanical drive were reached in case of electric drive. At hypothetical use of batteries (100% electro-powered tractor) and when the energy mix at Czech Republic is taken into consideration, it is possible to reach the quarter values of emissions production in comparison with combustion engine.

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1743–1755 P. Prochazka, A. Murjan, V. Hönig and K. Pernica
Some factors affecting the efficiency of potato production, under Al–Ghab plain conditions, Syrian Arab Republic
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Some factors affecting the efficiency of potato production, under Al–Ghab plain conditions, Syrian Arab Republic

P. Prochazka¹*, A. Murjan¹, V. Hönig² and K. Pernica²

¹Czech University of Life Sciences Prague, Faculty of Economics and Management, Department of Economics, Kamýcka 129, CZ165 21 Prague 6, Czech Republic
²University of Economics, Faculty of Business Administration, Department of Strategy, W. Churchill Sq., CZ130 67 Prague 3, Czech Republic
*Correspondence: pprochazka@pef.czu.cz

Abstract:

Data were collected by a field survey of 300 farmers from Al–Ghab region (Syria) during 2014–2015. The non–parametric Data Envelopment was used in analyzing the Technical efficiency. The relationship between farm size and production efficiency was considered. Technical efficiency amounted about 53% and most of farms are operating at low level of technical efficiency. The relationship between farm size and productivity efficiency is Non–linear, it decreases from small to medium farm size and then increases as the size increase. Large farms have the higher net farm income per thousand square meters and are the most efficient technically followed by small and medium farm size. To disclose that factors causing the technical efficiency, Two–limit Tobit Regression Model was used. The calculated results showed that, Household Size, Occupation, Farm Size, Experience in Farming, Seed Type and Membership are factors that cause the technical inefficiency potato farming at Al–Ghab region. Therefore, the Syrian Planning Board and Decision Makers should take this results into account when they draw their plans to improve farmer’s skills by allocating more investment in farm research and extension programmers.

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1756–1770 R. Raimla and E. Merisalu
Effectiveness of simulation models on technical skills among surgeons. A critical review
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Effectiveness of simulation models on technical skills among surgeons. A critical review

R. Raimla* and E. Merisalu

Estonian University of Life Sciences, Institute of Technology, Husbandry Engineering and Ergonomics, Fr.R. Kreutzwaldi 56, EE51014, Tartu, Estonia
*Correspondence: riin.raimla@emu.ee

Abstract:

Based on simulation models the surgeons can train technical skills and improve their functional status of musculoskeletal state. Work in good ergonomic position could reduce and prevent musculoskeletal disorders. The aim of this review is to carry out critical analysis of research on simulation techniques analysing the effectiveness of simulators on technical skills among the surgeons. The search of the articles based on the databases EBSCO, Science Direct and Web of Science. The articles published in 2011–2016 years and not the literature reviews of simulator models in surgery were the selection criteria. Most often the simulator models have used for training of laparoscopic operations, choosing new instruments or introducing new methodologies. Some articles have paid more attention to ergonomic equipment layout in practice to prevent musculoskeletal disorders. It is important to use simulators in the university hospitals, where the young surgeons and medical students are practicing.

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1771–1781 I. Riivits-Arkonsuo, M. Ojasoo, A. Leppiman and K. Mänd
Fair Trade and social responsibility – whose duty? Estonian consumers’ attitudes and beliefs
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Fair Trade and social responsibility – whose duty? Estonian consumers’ attitudes and beliefs

I. Riivits-Arkonsuo¹*, M. Ojasoo¹, A. Leppiman¹ and K. Mänd²

¹Tallinn University of Technology, Faculty of Economics, Institute of Business Administration, Ehitajate 5, EE19086 Tallinn, Estonia
²MTÜ Mondo, Telliskivi 60A, EE10412 Tallinn, Estonia
*Correspondence: iivi.riivits@ttu.ee

Abstract:

This article investigates how the Estonian consumers endorse the idea of Fair Trade (FT) and understand the principles of social responsibility. The article is based on a study on Fair Trade and social responsibility conducted in 2014. The study examined the consumers’ attitudes and beliefs associated with FT and local Estonian agricultural production. The article aims to compare if there are any difference in the beliefs and attitudes among the Estonian consumers towards supporting local farmers and producers versus supporting the FT ideas which benefit the farmers and producers from the Global South. The authors fully recognize that there is no competition among these two groups per se, but the perception exists in the minds of the consumers. The respondents of the nation-wide representative sample (n = 1,007) evaluated the responsibility of different economic agents such as public sector, retailers, suppliers, producers, and consumers. Most of the respondents regarded the principle of social responsibility as giving the priority to local Estonian agricultural production. The Estonian consumers tend to be skeptical about the benefits of FT or the workers and farmers from the developing countries. The awareness and knowledge about FT ideas is not high.

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1782–1794 H. Roubík, J. Mazancová, R.C. Situmeang, A. Brunerová and T.M. Simatupang
Livestock manure management practices in rural households in Tapanuli Utara regency of North Sumatra
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Livestock manure management practices in rural households in Tapanuli Utara regency of North Sumatra

H. Roubík¹, J. Mazancová¹*, R.C. Situmeang², A. Brunerová³ and T.M. Simatupang²

¹Czech University of Life Sciences Prague, Faculty of Tropical AgriSciences, Department of Sustainable Technologies, Kamýcká 129, CZ 165 00 Prague, Czech Republic
²Del Institute of Technology, Faculty of Industrial Technology, Department of Engineering Management, Kabupaten Toba Samosir, Sumatera Utara ID 22381, Indonesia
³Czech University of Life Sciences Prague, Faculty of Engineering, Department of Material Science and Manufacturing Technology, Kamýcká 129, CZ 165 00 Prague, Czech Republic
*Corresponding author: mazan@ftz.czu.cz

Abstract:

Livestock manure management is a big challenge for low income economies including the region of North Sumatra, Indonesia. Currently, low percentages of manure managed cause illegal disposals, and negative impacts on public health and environment. Therefore, the objective of this study was to assess the current trends among livestock manure management practices in rural households and to recognize potential problems with it. The questionnaire survey using randomly selected households (n = 196) was administered in the province of North Sumatra, Tapanuli Utara regency, from July to August 2014; then followed by several field visits from August to September 2016. Data obtained in the survey were analysed with descriptive statistics and cross tabulation. Majority (81%) of rural households handle manure in the process of either composting (75%) or sun-drying (6%). Remaining 6% of the respondents does not handle manure at all. Manure could represent valuable energy and plant nutrition resource, if used appropriately. However, if not handled at all or handled inappropriately, it can lead to the environmental problems. Our results revealed that current ways of stabling of livestock are inappropriate from the environmental perspective. The stabling has got only dusty earthen floor, which makes difficult for farmers wash out the excrements and pollution. Hence, there is a need to improve manure management practice to eliminate potential threats as current practices do not protect either humans, animals or environment against the risk of contamination with potential zoonotic pathogens.

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1795–1814 M. Welc, A. Lundkvist, N-E. Nordh and T. Verwijst
Weed community trajectories in cereal and willow cultivations after termination of a willow short rotation coppice
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Weed community trajectories in cereal and willow cultivations after termination of a willow short rotation coppice

M. Welc*, A. Lundkvist, N-E. Nordh and T. Verwijst

Department of Crop Production Ecology, Swedish University of Agricultural Sciences, P.O. Box 7043, SE-750 07 Uppsala, Sweden
*Correspondence: Monika.Welc@slu.se

Abstract:

According to guidelines for willow short rotation coppice (SRC), weeding is needed during establishment, while weed populations which develop later under a well-established willow canopy do not require control. However, farmers are concerned that weeds which develop in SRC may result in long-lasting weed infestations in succeeding crops after SRC termination. We assessed the effects of two SRC-termination methods (with shallow and deep soil cultivation) on the development of the weed flora in a cereal system (CS) and in SRC during six seasons. Richness, ground cover, life-cycle strategy and composition of the weed species, and their environmental requirements (inferred from Ellenberg index) were evaluated.
SRC-termination method had no effect on the weed community trajectories in the succeeding SRC and CS. However, cropping system and growing season had significant impacts on species richness, ground cover and composition of the weed flora.
Differences in weed communities over time and between cropping systems were related to the impact of cropping systems on factors such as light, soil moisture, nitrogen level, and soil reaction, as inferred from the Ellenberg index. After termination of the old willow cultivation, the weed flora of the SRC and CS rapidly diverged and approached the weed flora characteristic for old willow stands and non-weeded old cereal plot, respectively. We conclude that willow stands can be converted, regardless of termination method, either into willow or cereal cultivations without additional risk of weed infestations other than those specific for their respective cropping systems. Furthermore, willow cultivations in agriculture contribute to floristic diversity at the landscape scale.

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