Theoretical research of force interaction of a flexible cleaning blade with a beet root head

ArticleThe most common technology of removing the sugar beet haulm in the world is a continuous cut of the entire mass of the green haulm with further additional removal of the upper parts of the sugar beet heads, which is carried out without extracting the roots from the ground. This is the scheme according to which most top harvesting machines, manufactured in the world, now operate. However, we have found in our studies that, due to additional cutting off the upper parts of the root crop heads, up to 10% of the sugar-bearing mass is lost. Besides, there is an urgent need for immediate processing of the sugar beet root crops, as losses of the sugar juice occur, and bacteria enter inside of the root crop through the cut-off part, causing rotting. Therefore, a more favourable operation for harvesting root crop tops is not cutting off their heads but cleaning them from the residues of the foliage. In addition, the operation of cleaning the sugar beet roots from the residues of the foliage is subject to rather high requirements due to the absence of the green and dry residues on the heads of the roots, as well as the losses and damage of the root crops themselves. The purpose of this investigation is to develop a theory of the force interaction of the flexible cleaning blade with the sugar beet head in the process of its cleaning when the blade is mounted on the vertical driving shaft. The methods used of the investigation are those of modelling, higher mathematics and theoretical mechanics, as well as programming and numerical calculations on the computer. As a result of the research, an equivalent scheme was developed and a mathematical model was constructed describing the force interaction of the flexible cleaning blade with the surface of the sugar beet root

Theory of retaining potato bodies during operation of spiral separator

ArticleThe increase of the efficiency and quality of performance of the work process of potato heap separation can be achieved by means of improving the design of the vibrational spiral separator and substantiating theoretically its rational parameters under the condition of eliminating damage to the potato tubers. An equivalent schematic model of the interaction between the potato tuber and the surface of the cantilever spiral springs has been devised. On the basis of the model, the kinematic characteristics of the tuber’s flight and its impact contact with the elastic surface of the over mounted rebounding conveyor have been investigated. A new analytical mathematical model of the potato tuber’s flight from the surface of the spiral separator and its subsequent encounter with the rebounding conveyor mounted above the spiral springs has been developed. New analytical dependences have been obtained for finding out the distance and height of the potato tuber’s flight to the point of impact contact as well as the trajectory equation fo r the travel to the said contact, which makes it possible to obtain the kinematic constraints imposed on the allowed rate of travel under the condition of not damaging the tuber. On the basis of the obtained analytical dependences, the kinematic parameters of the improved design of the spiral potato harvester separator in its interaction with a potato tuber under the condition of not damaging the latter have been investigated

Experimental research into uniformity in spreading mineral fertilizers with fertilizer spreader disc with tilted axis

Received: February 2nd, 2021 ; Accepted: March 27th, 2021 ; Published: April 7th, 2021 ; Correspondence: [email protected] the efficiency in the work process of mineral fertilizer dressing is a topical problem in today’s agricultural industry. The authors have developed a design of the fertilizer spreading tool with a tilted axis and carried out field experiment investigations on it. It has been established by the results of the investigations that the non-uniformity in the spreading of mineral fertilizers along the line of their departure from the fertilizer spreading tool with a tilted axis is most strongly affected by the disc rotation frequency. The obtained results provide for selecting the optimum parameters and modes of operation for the tool under consideration in the situation, when it is installed in fertilizer placing machines. Also, it has been established that increasing the spreading disc rotation frequency in such a tool from 600 to 800 rpm results in the growth of the effective range of mineral fertilizer spreading along the placing line at a level of 10.5 m. Increasing the disc’s angle of inclination to the horizontal plane to 20º results in the rise of the effective fertilizer spreading range at a level of the 48th tray (24 m) inclusive as well as the increase of the distance between the tool and the tray that contains the maximum share of the spread fertilizers (5.1%) to 24 trays (12 m). At a constant rotation frequency of the disc in the tilted-axis fertilizer spreading tool, in all its kinematic modes of operation, an increase in the angle of its disc’s inclination to the horizontal plane results in the rise of the indices representing the distribution of the mineral fertilizers over the trays along the line of their placing. The width of the mineral fertilizer spreading can be controlled by adjusting the rotation frequency of the disc in the tilted-axis fertilizer spreading tool, when it is set at an angle to the horizontal plane, similar to how it is done in state-of-the-art fertilizer placing machines with horizontally positioned discs in their centrifugal spreading tools. The rotation frequency of the disc in the tilted-axis fertilizer spreading tool has the most significant effect on the coefficient of variation incidental to the distribution of the mineral fertilizers along the line of their placing

Research into engineering and operation parameters of mineral fertiliser application machine with new fertiliser spreading tools

Received: February 13th, 2021 ; Accepted: April 15th, 2021 ; Published: April 19th, 2021 ; Correspondence: [email protected] output capacity of the machine for top spreading the soil with solid mineral fertilisers can be raised by means of increasing its working width. The authors have carried out field trials and field experiment investigations with the MVU-8 granulated mineral fertilizer spreading machine equipped with two prototype units of the centrifugal fertiliser spreading tool, in which the axis can be tilted at different angles to the vertical line. In accordance with the results of the completed investigations, it has been established that setting the axial tilt angle of the centrifugal operating device in the fertiliser spreading tool within the range of 25–30° provides for achieving a productivity of the combined tractor-implement unit for applying mineral fertilisers at a level of 35–40 ha per working shift hour. The best performance in the fertiliser application with regard to both the working width and the fertiliser placing distribution uniformity is ensured at angles of inclination of the disc in the fertiliser spreading tool with respect to the horizontal plane within the range of 25–30°. At these angles, the uneven distribution of the fertiliser over the working width is equal to 19.2%, the uneven distribution of the fertiliser along the unit’s line of travel is equal to 8.9%, while the deviation in the dosage of the applied fertilisers from the set value is equal to 7.5%

Experimental research into uniformity in spreading mineral fertilizers with fertilizer spreader disc with tilted axis

Improving the efficiency in the work process of mineral fertilizer dressing is a topical problem in today’s agricultural industry. The authors have developed a design of the fertilizer spreading tool with a tilted axis and carried out field experiment investigations on it. It has been established by the results of the investigations that the non-uniformity in the spreading of mineral fertilizers along the line of their departure from the fertilizer spreading tool with a tilted axis is most strongly affected by the disc rotation frequency. The obtained results provide for selecting the optimum parameters and modes of operation for the tool under consideration in the situation, when it is installed in fertilizer placing machines. Also, it has been established that increasing the spreading disc rotation frequency in such a tool from 600 to 800 rpm results in the growth of the effective range of mineral fertilizer spreading along the placing line at a level of 10.5 m. Increasing the disc’s angle of inclination to the horizontal plane to 20º results in the rise of the effective fertilizer spreading range at a level of the 48th tray (24 m) inclusive as well as the increase of the distance between the tool and the tray that contains the maximum share of the spread fertilizers (5.1%) to 24 trays (12 m). At a constant rotation frequency of the disc in the tilted-axis fertilizer spreading tool, in all its kinematic modes of operation, an increase in the angle of its disc’s inclination to the horizontal plane results in the rise of the indices representing the distribution of the mineral fertilizers over the trays along the line of their placing. The width of the mineral fertilizer spreading can be controlled by adjusting the rotation frequency of the disc in the tilted-axis fertilizer spreading tool, when it is set at an angle to the horizontal plane, similar to how it is done in state-of-the-art fertilizer placing machines with horizontally positioned discs in their centrifugal spreading tools. The rotation frequency of the disc in the tilted-axis fertilizer spreading tool has the most significant effect on the coefficient of variation incidental to the distribution of the mineral fertilizers along the line of their placing

Individual and organisational factors in the psychosocial work environment are associated with home care staffs’ job strain: A Swedish cross-sectional study

Background Home care staff (HCS) provide essential service to enable older adults to age in place. However, unreasonable demands in the work environment to deliver a safe, effective service with high quality has a negative impact on the individual employee’s well-being and the care provided to the older adults. The psychosocial work environment is associated with employees´ well-being, although, knowledge regarding which individual and organisational factors that contribute to job strain for HCS is limited. These factors need to be identified to develop targeted interventions and create sustainable work situations for HCS. This study aimed to explore how HCS´s perceived job strain is associated with, and to what extent can be explained by, individual and organisational factors of the psychosocial work environment and psychosomatic health. Method An explorative cross-sectional questionnaire survey design was used in a large Swedish county. Five home care agencies with a total of 481 HCS were asked to respond to a questionnaire regarding their perceived level of job strain (Strain in Dementia Care Scale), psychosocial work environment (QPSNordic34+), and psychosomatic health (Satisfaction with Work Questionnaire). Multiple linear regression (MLR) analyses were conducted to explore the association between job strain and individual and organisational factors. Results In total, 226 (46%) HCS responded to the questionnaire. Both individual and organisational factors were significant predictors of job strain and explained a variance ranging between 39 to 51% (p = 0.001). The organisational factor job demand and the individual factor feeling worried and restless was most frequently represented in these MRL models. A higher job strain was also associated with adverse outcomes regarding leadership, organisational culture and climate, and control at work. Conclusion This study indicates that there is an intertwined complexity of individual and organisational factors that are associated with the HCS´s perception of job strain. Implementation of new multidimensional work strategies, such as a reablement approach, could support the development of efficient strategies for HCS and reduce the level of job strain. Policy changes for the provision of home care are also needed to support the development of a sustainable and healthy psychosocial work environment

Theory of impact interaction between potato bodies and rebounding conveyor

ArticleIn order to increase substantially the quality of the potato heap separation, it is necessary to carry out the theoretical substantiation of the spiral separator’s parameters with regard to the impact interaction between the product and the tools of the un it under the condition of not damaging the tubers. An equivalent schematic model of the impact interaction between a potato tuber and the surface of the rebounding conveyor has been devised. Taking into account the coefficient of restitution of the tuber’s velocity in case of an impact, new analytical expressions have been obtained for determining the magnitude and direction of the potato tuber’s velocity after the impact. They provided the basis for applying the principle of momentum at impact and obtainin g the analytical expressions that allow determining the impact impulse and impact force at the impact of the tuber on the surface of the rebounding conveyor and, eventually, the dynamic constraints on the permitted velocity of the tuber prior to the impact interaction under the condition of not damaging it. A new analytical mathematical model of the impact interaction of the potato tuber during the potato heap separation has been developed. On the basis of the obtained theoretical results, studies have been carried out on the rational kinematical parameters of the high - quality performance of the above - mentioned work process under the condition of keeping the potato tubers undamaged

The coupling between Ca2+ channels and the exocytotic Ca2+ sensor at hair cell ribbon synapses varies tonotopically along the mature cochlea.

The cochlea processes auditory signals over a wide range of frequencies and intensities. However, the transfer characteristics at hair cell ribbon synapses are still poorly understood at different frequency locations along the cochlea. Using recordings from mature gerbils, we report here a surprisingly strong block of exocytosis by the slow Ca(2+) buffer EGTA (10 mM) in basal hair cells tuned to high frequencies (∼30 kHz). In addition, using recordings from gerbil, mouse and bullfrog auditory organs, we find that the spatial coupling between Ca(2+) influx and exocytosis changes from nanodomain in low-frequency tuned hair cells (∼2 kHz). Hair cell synapses have thus developed remarkable frequency-dependent tuning of exocytosis: accurate low-latency encoding of onset and offset of sound intensity in the cochlea's base and submillisecond encoding of membrane receptor potential fluctuations in the apex for precise phase-locking to sound signals. We also found that synaptic vesicle pool recovery from depletion was sensitive to high concentrations of EGTA, suggesting that intracellular Ca(2+) buffers play an important role in vesicle recruitment in both low- and high-frequency hair cells. In conclusion, our results indicate that microdomain coupling plays an important role in the exocytosis of high-frequency hair cells, and suggest a novel hypothesis for why these cells are more susceptible to sound-induced damage than low-frequency cells; high-frequency IHCs must have a low Ca(2+) buffer capacity in order to sustain exocytosis, thus making them more prone to Ca(2+)-induced cytotoxicity. SIGNIFICANCE STATEMENT: In the inner ear, sensory hair cells signal reception of sound. They do this by converting the sound induced movement of their hair bundles present at the top of these cells, into an electrical current. This current depolarizes the hair cell and triggers the calcium-induced release of the neurotransmitter glutamate that activates the postsynaptic auditory fibres. The speed and precision of this process enables the brain to perceive the vital components of sound such as frequency and intensity. We show that the coupling strength between calcium channels and the exocytosis calcium sensor at inner hair cell synapses changes along the mammalian cochlea such that the timing and/or intensity of sound is encoded with high precision

Research into engineering and operation parameters of mineral fertiliser application machine with new fertiliser spreading tools

The output capacity of the machine for top spreading the soil with solid mineral fertilisers can be raised by means of increasing its working width. The authors have carried out field trials and field experiment investigations with the MVU-8 granulated mineral fertilizer spreading machine equipped with two prototype units of the centrifugal fertiliser spreading tool, in which the axis can be tilted at different angles to the vertical line. In accordance with the results of the completed investigations, it has been established that setting the axial tilt angle of the centrifugal operating device in the fertiliser spreading tool within the range of 25–30° provides for achieving a productivity of the combined tractor-implement unit for applying mineral fertilisers at a level of 35–40 ha per working shift hour. The best performance in the fertiliser application with regard to both the working width and the fertiliser placing distribution uniformity is ensured at angles of inclination of the disc in the fertiliser spreading tool with respect to the horizontal plane within the range of 25–30°. At these angles, the uneven distribution of the fertiliser over the working width is equal to 19.2%, the uneven distribution of the fertiliser along the unit’s line of travel is equal to 8.9%, while the deviation in the dosage of the applied fertilisers from the set value is equal to 7.5%

Theory of grain mixture particle motion during aspiration separation

The practice of separating grain mixtures with the use of the difference in the aerodynamic properties of their components has proved that the process of separating mixtures in the aspiration separator is the most promising one with regard to the improvement of quality and intensification of production. The authors have developed a new improved design of aspiration seed separators, in which the work process of separating seed material is performed with the use of vibration processes. In this seed material separator, the constant force air flow that acts on the sail members on the central pipe of the separator, when seeds are fed for processing, generates self-excited oscillations in the pipe, which produces centrifugal forces of inertia in the seed feeding system. As a result of the mentioned effect, the propelling force in the process under study substantially increases, accelerating the seeds of different fractions, which differ in their masses, to different velocities. The motion paths of the seed particles change accordingly, heavier particles moving closer to the vertical axis of the aspiration channel, which provides for increasing the efficiency of separation of the seeds of different fractions from each other. In this paper, a new mathematical model is developed for the motion of a seed mixture material particle in the operating space of the separator’s aspiration channel. The mathematical modelling of the process of vibration and aspiration separation has indicated that the separation of the motion paths of the medium and heavy fractions takes place within the range of 20–40 mm; the flying speed of the particles is equal to 3.2–8.0 m s–1, respectively; and their acceleration is equal to 1.8– 3.3 m s–2, which provides the necessary conditions for the accurate and high quality separation into the required fractions. In view of the found differences between the kinematic characteristics of the separated fractions of the grain mixture, the diameter of the pipeline for the medium fraction is to be within the range of 90–100 mm, for the heavy fraction – 50–70 mm