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Despite the high nutritional value of cowpea and its potential for sustainable farming, its cultivation is limited by the lack of vegetable varieties adapted to different soil and climatic conditions, which complicates the fight against food insecurity in many countries. Therefore, this study aims to conduct a comprehensive evaluation of cowpea (Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc.) varieties with the aim of identifying genotypes with high productivity potential and resistance to the main adverse environmental factors of the Right-Bank Forest-Steppe of Ukraine. The experimental study was carried out in a three-year period (2014–2016). Depending on the variant of the experiment, cowpea germination was observed from 25 May to 30 May. The shortest sowing–shoot period (10 days) was observed in the variety ‘U-Tya-Kontou’ (China), with the longest (13 days) in the varieties ‘Kafedralna’ (Ukraine) and ‘American Improved’ (USA). In the control variant, shoots were obtained on 28 May. Flowering started from 9 July to 16 July; technical maturity (unripe (green) beans) started from 27 July to 2 July; and biological maturity of the seeds started from 30 August to 5 September. For the variety ‘American Improved’, the shortest period of seedling–technical maturity (unripe (green) beans) (58 days) and seedling–biological maturity (92 days) was recorded. By cultivar, the maximum plant height was achieved with varieties ‘Groik’ (Israel) at 100.5 cm and ‘Gasson’ (Vietnam) at 61.8 cm, which are 52 cm and 13.3 cm more than the control height. They differ by the quick growth of the main and side shoots, which allows them to be grown on supports. The highest yield of green beans was recorded in the cowpea variety ‘Gasson’ at 14.4 t∙ha−1, which is 38.5% higher than the control. In the variety ‘Groik’, the yield of green beans (11.4 t∙ha−1) did not differ significantly from the control (‘Kafedralna’—10.4 t∙ha−1). The varieties ‘U-Tya-Kontou’ and ‘American Improved’ were characterized by the lowest yield of green beans, which reached 5.8 and 4.2 t∙ha−1, respectively, which is 44.2 and 59.6% less than the control. As a result of statistical analysis of cowpea yields, the limits of its fluctuation were established as follows: fluctuations in the sum of effective temperatures by 10 °C (>10 °C) contributed to a deviation in green bean yields from 20.0 to 24.7 kg (ha)−1, and fluctuations in precipitation by 10 mm contributed to a deviation in green bean yields in the range from 34.3 to 208.2 kg (ha)−1. The results of the study presented in this article have practical application for the development of effective methods of growing local varieties of long-stemmed cowpea, which will increase yields and meet the needs of both farmers and consumers in regions with similar climatic conditions.

In this paper we study the problem of the diffusion of one substance through the pores of a porous multi layered material which may absorb and immobilize some of the diffusing substances with the evolution or absorption of heat. As an example we consider circular cross section wood-block with two layers in the radial direction. We consider the transfer of heat process. We derive the system of two partial differential equations (PDEs) - one expressing the rate of change of concentration of water vapour in the air spaces and the other - the rate of change of temperature in every layer. The approximation of corresponding initial boundary value problem of the system of PDEs is based on the conservative averaging method (CAM) with special integral splines. This procedure allows reduce the 3-D axis-symmetrical transfer problem in multi-layered domain described by a system of PDEs to initial value problem for a system of ordinary differential equations (ODEs) of the first order.

Abstract The aim of the study was to develop and analyze various black chokeberry (Aronia melanocarpa (Michx.)) products using waste-free treatment technology. The chemical composition of black chokeberry berries, and various processed products made from them (juice, pomace, pomace water extract, dried sweetened pomace, and syrup) are described. The effect of activated carbon (AC) on the reduction of proanthocyanidins content in black chokeberry berry juice and water extract and the effect of ascorbic acid additive on the sensory properties of dried sweetened pomace were investigated. Principal component analysis (PCA) resulted in one compact group of products representing the solid products of black chokeberry, and the first two factors of the PC1 (total anthocyanins and flavonoid content) described 98.38% of the total variability. It was concluded that AC allowed for reducing the content of proanthocyanidins in juices but did not affect their taste. However, reduced proanthocyanin content reduces the functionality of the products, and this information must be considered in new product development. The addition of ascorbic acid to dried sweetened black chokeberry pomace did not significantly affect the degree of liking of dried sweetened pomace. Black chokeberry products developed by waste-free technology are rich in biologically active compounds and could be used to produce new functional products.

One of the most delicate operations in the sugar beet harvesting process is removing the tops from the heads of the root crops without any mechanical damages. The aim of this study is to improve the design of the conveying and unloading system of the sugar beet topper machine. In this paper, a mathematical model of the motion of a cut beet tops particle M, along the conveying and unloading system, has been developed to support the evaluation of kinematic and design parameters, depending on the rotational speed of the thrower blade, the air flow speed, the required ejection speed of particle M, and the position of the trailer that moves alongside the harvester. It has been established that increasing the speed Va of the top particle M, which has left the end of the blade of the thrower, leads to an increase in the arc coordinate S(t) of its movement along the cylindrical section of the casing. Within the range of the speed change from 4 m·s–1 to 8 m·s–1, the value of the arc coordinate S(t) increases by 1.4 times during time t = 0.006 s. Moreover, a rapid decrease in speed V is observed with an increase in the length x of the discharge chute.

A new design of the haulm harvester with an improved loading mechanism has been developed, which is made in the form of a centrifugal thrower that receives the entire volume of the cut sugar beet tops, as well as an unloading pipe, the end of which is at the level of the vehicle, moving beside the haulm harvester. To substantiate the rational parameters of this loading device, a mathematical model of the movement of a particle along the thrower blade and its exit from the blade was developed in order to simulate further movement along the inner surface of the cylindrical part of the casing and its straight part before entering the vehicle. The resulting differential equation for the movement of a haulm particle along the thrower blade takes into account the influence of the airflow created by the rotation of the thrower, the blades of which capture and accelerate the air in the closed space of the cylindrical casing. The indicated differential equation includes the basic design, kinematic, and power parameters affecting the flow of the studied loading process of the tops. The solution of these differential equations on a PC made it possible to obtain graphic dependencies, with the help of which the rational parameters of the working bodies of the loading mechanism of the haulm harvester were substantiated. As calculations show, an increase in the angular velocity of rotation of the thrower and the length of its blade leads to an increase in the absolute velocity of the haulm particle M from the end of the blade. Thus, by increasing the length of the thrower blade from 0.1 m to 0.35 m and its angular velocity from 10 s−1 to 40 s−1, the absolute velocity increases from 1.2 m s−1 to 16 m s−1. At an angular speed of rotation of the thrower equal to 10 s−1, an increase in the airflow velocity from 5 to 35 m s−1 leads to a smooth linear increase in the relative velocity of particle M, as it moves along the blade of 0.67 to 0.78 m s−1. For a higher angular velocity of rotation of the thrower, equal to 20 s−1, the growth curve of the relative velocity of particle M is more intense at an airflow velocity in the range from 5 to 25 m s−1, approaching the linear law at an airflow velocity of more than 25 m s−1. In this case, the relative velocity varies from 0.9 to 1.4 m s−1.

Photovoltaic (PV) systems are becoming more and more popular around the world, and Latvia is not an exception. This is mainly due to the increased efficiency and reduction in price of PV modules. However, Latvia still ranks below most European Union countries in the use of PV modules for electricity production. A significant problem for many farms and households in Latvia which use PV modules, is the lack of storage for the produced electricity. As a result, large amounts of electricity are sold for a relatively low price and while being bought from the main grid for a relatively high price. The aim of the study is to determine and compare the electricity consumption and PV systems producing electricity each month on the Jasmini Farm during 2020. The study shows that during the year, only 25.4% of all the electricity used on the Jasmini Farm was from PV modules, but the rest of the electricity was bought from the main grid. Furthermore, from all the electricity which PV modules produced in 2020, only 29.5% was used on the farm, while the rest was sold to the main grid.

One of the directions for expanding the functional properties of modular draft devices (MDD) is their use with semitrailers (using a fifth-wheel coupling, installed on the technological module). The issue with this is due to their ability to create such a redistribution of the MDD operational mass along the semitrailer’s axles whereby the loss of control of the entire transport aggregate is possible. To solve this problem, regularities have been established to consider in choosing the design parameters of the MDD. It has been established by theoretical calculations that an increase in the angle of inclination of the central α, with negative values of the angle of inclination of the lower β links of the rear-mounted mechanism of the MDD’s power module (PM), leads to an increase in the vertical load of the wheels of its technological module. The transition of the longitudinal coordinate point of the semitrailer’s tractive resistance application from −0.30 m to +0.30 m, provided α > β, leads to an increase in the vertical load on the wheels of its technological module. Increasing the angles of inclination of the central and lower links of the rear linkage of the PM leads to an increase in the vertical load on the wheels of its front axle. An exception is the option in which the lower links of the specified linkage mechanism are set at a negative angle at the level of −10°. An increase in the value of the angle of inclination of the central value, with positive values of the angle of inclination of the lower links of the rear-mounted mechanism of the PM, and compliance with the condition α < β, leads to a decrease in the vertical load of the wheels of the technological module.

Harvesting sugar and fodder beet tops is a complex technological process that requires the use of special harvesting machines. Trailed harvesters of different rows, which together with aggregate tractors form symmetric or asymmetric machine-tractor units, the movement of which in the horizontal plane is not always stable, are widely used. The purpose of this study is to determine the parameters of stable plane-parallel motion of asymmetric harvester machine-tractor unit based on numerical computer simulation of the obtained analytical dependencies. According to the results of the analytical study, the values of the amplitude and phase-frequency characteristics of the turning angle tractor’s oscillations were obtained. They reflect the reproduction by the angle rotation fluctuations of the haulm harvester machine in the horizontal plane. Calculations have shown that reducing the value of the input resistance coefficient of pneumatic tires of the driving wheels of the aggregating tractor increases its sensitivity to the action of disturbing influences. The greater the sensitivity, the closer the wheels of the power tool are to the attachment point of the trailed haulm harvester. In qualitative terms, increasing the speed of the machine-tractor unit from 1.5 to 2.5 m∙s−1 leads to an undesirable increase in the amplitude-frequency response and desired increase in the phase-frequency response when reproducing its external disturbing effects in the form of oscillations of the angle of rotation of the harvester.

Šiandieniniame gyvenime, mechanizavus pramonės ir žemės ūkio gamybą, didėjant transporto srautams miestuose ir gyvenvietėse, sparčiai didėja padidinto triukšmo zonos. Žmones vargina triukšmas ne tik darbo vietose, bet ir gatvėse, namuose. Medikai teigia, kad triukšmas, kaip lėtinis streso šaltinis, veikia centrinę nervų sistemą ir kelia įvairių sutrikimų. Net palyginti nestiprus 60–70 dB triukšmas sukelia galvos skausmą, svaigimą, nemigą, pablogėja atmintis, dėmesys, orientacija. Triukšmingoje aplinkoje blogėja darbingumas, sutrinka judesių koordinacija, didėja nervinė įtampa ir traumų rizika. Šiame straipsnyje pateikiamas kiekybinis Dovilų miestelio gyventojų pasitenkinimo dabartiniu triukšmo lygiu tyrimas. Buvo pasirinktas 800 respondentų atrankos klausimyno metodas. Tyrimo tikslinė grupė yra Dovilų miestelio gyventojai (respondentai). Klausimynas buvo išsiųstas visiems miestelio gyventojams (1300 gyventojų). Atsakė 800 respondentų.

One of the most important parameters that characterize the traction-coupling properties of a wheeled tractor is its slip. The more tractor’s gross traction exists, the higher its traction-coupling properties are. However, this gross traction should not exceed its maximum possible value, which, in turn out, is to be determined by the maximum permissible slip, δmax. This article provides the equation to calculate this crucial parameter and establishes the dependencies between the tractor’s slip and soil structure coefficient. It was shown that the value of δmax basically depends on such soil characteristics as the bulk deformation coefficient and the coefficient of rolling resistance. Calculations showed that, for the average value of the soil bulk deformation coefficient at 4000 kN·m−3, the average value of rolling resistance coefficient at 0.16, and the ratio value of the maximum permissible soil pressure to the tractor wheel rolling radius at 222 kPa·m−1, the maximum permitted amount slip of the tractor wheels should not exceed 15%. With more slip, the soil structure deteriorates significantly. In this case, its structure coefficient may be less than critical, equal to 0.4.

The article presents research results of a machine-tractor unit that performs two technological operations simultaneously: (i) chopping plant residues (sunflower stubble); (ii) covering the chopped stubble with the soil. The first operation is carried out with a front-mounted plant residues chopper, and the second one is carried out with a rear-mounted plough. The chopper’s working devices are rotated by the tractor’s front power take-off (PTO), which has two operating modes: 540 and 1000 rpm. It was determined that to reduce the dynamic load in the drive of the chopper’s plant residues working devices, to chop these residues qualitatively, and then to cover them with the soil, the tractor’s front PTO should be adjusted to a speed of 1000 rpm. With this mode of the chopper’s working device’s rotation, the difference in its vertical vibrations’ dispersion and the tractor front axle’s oscillations is insignificant. The variance of the plowing depth vibrations (1.44 cm2), changing aperiodically in the frequency range of 0–2.5 Hz, is not accidentally less than the variance of irregularities vibrations of the longitudinal field profile (2.75 cm2). The plough draft resistant oscillations of the plow-chopping unit had the least impaction at the plowing depth oscillations. The proof of this is the small value of the cross correlation function; for such oscillating processes as ‘plough draft resistance—plowing depth’, it was equal to 0.22, which is 3.4 times less than for oscillating processes ‘surface’s longitudinal profile—plowing depth’. The number of chopped particles less than 15 cm in length increased by 1.5 times, and the number of particles longer than 30 cm decreased by 3 times. With the complete incorporation of plant residues into the soil, their non-chopped part did not exceed 1%.

The new machine-and-tractor aggregate of a modular type, developed by us, consisting of the power and the technological modules, can significantly increase the efficiency of using the tractor when it is aggregated with a five-body plough. The new design solution for connecting these modules in a horizontal plane through a damper, consisting of a hydraulic cylinder and a throttle, allows significant increasing of the movement stability of this aggregate in a transverse-horizontal plane. To test the efficient operation of the proposed design, as well as to determine the kinematic and design parameters that provide the required level of stable movement of this modular machine-and-tractor aggregate, we carried out theoretical and experimental field investigations. For this, a new mathematical model of plane-parallel movement of the machine-and-tractor aggregate of this type was built. It was found that a change in the operating speed of this aggregate during ploughing from 1.0 to 3.0 m∙s−1 does not lead to a deterioration in the stability of the movement of either the technological or, especially, the power modules. The delay in the reaction of the power module of the machine-and-tractor aggregate of the modular type is practically invariant with respect to the change in the mode of movement of this aggregate within the range 1–3 m∙s−1. It was also found that the values of the tire slip resistance coefficients of the wheels of the power module do not have a noticeable impact upon the development of fluctuations of the disturbing moment.