scholarly journals DETERMINATION OF THE MAIN PARAMETERS OF THE ROTARY MOWER CUTTING APPARATUS

2020 ◽  
pp. 77-85
Author(s):  
Dmitry Kondratyuk ◽  
Vitaliy Komaha
Keyword(s):  
Cutting Speed ◽  
Soil Surface ◽  
Angular Speed ◽  
Working Length ◽  
Mode Of Operation ◽  
Basic Parameters ◽  
Rotary Cutting ◽  
The Difference ◽  
Translational Speed

For mowing grass during harvesting of hay or haylage, support-free mowers with rotary movement of knives are used mainly, the productivity of which is much greater than segment-finger mowers. Free-cutting cutting apparatuses with rotational movement of knives happen with their rotation around the vertical (rotary) and horizontal (rotary) axes. Mowers that are equipped with rotary cutting devices significantly grind grass, so they are used in mower-grinders and lawn mowers. The purpose of the work is to substantiate the methodology for calculating the structural and kinematic parameters of rotary cutting devices, corresponding to the conditions of their use. The main parameters characterizing the operation of rotary cutting devices are: area, mows than in one revolution of the disk; knife working length; overlapping knives of adjacent rotors; cutting speed. In determining the basic parameters of the rotary cutting apparatus of the mower, the following assumptions were made. It was believed that the angular speed of the rotor and the translational speed of the mower are unchanged, and the movement of the unit is straightforward. In addition, the cutting apparatus performs mowing in a plane parallel to the soil surface, that is, in a plane perpendicular to most plant stems. It is shown that the absolute speed of any point of the knife varies from the maximum value equal to the sum of the peripheral speed of this point and the aggregation speed of the mower, to the minimum - the difference of the above speeds. It was found that the working length of the cutting edge of the knife is directly proportional to the speed of aggregation of the mower and inversely proportional to the angular velocity of the rotor and the number of knives mounted on it. The overlap of the path of the knives of adjacent rotors depends on the radius of the rotor; the number of knives mounted on it and the kinematic mode of operation of the cutting apparatus. Moreover, an increase in the radius of the rotor requires an increase in overlap, and an increase in the kinematic mode and the number of knives leads to a decrease in the overlap between the paths of the knives. The resulting dependence, which allows you to determine the area, mows than in one revolution of the rotor.

Thermal Behavior and Tool Failures on Rotary Cutting of Difficult-to-Cut Materials Utilizing Multi Tasking Lathe

2010 ◽  
Vol 447-448 ◽  
pp. 806-810 ◽  
Author(s):  
Hiromasa Yamamoto ◽  
Kentaro Satake ◽  
Hiroyuki Sasahara ◽  
Toru Narita ◽  
Masaomi Tsutsumi ◽  
...  
Keyword(s):  
Failure Modes ◽  
Single Point ◽  
Cutting Speed ◽  
Tool Failure ◽  
Average Temperature ◽  
Rotary Cutting ◽  
The Difference ◽  
Coated Carbide ◽  
Coated Carbide Tools ◽  
Cutting Speeds

In rotary cutting difficult-to-cut materials, less tool wear is observed at higher cutting speeds, contrary to the case of conventional single-point turning. In order to examine this characteristic feature of rotary cutting, this study focuses on the effects of cutting speed and tool peripheral speed on tool failure. Dry rotary cutting tests of stainless steel SUS304 were carried out using coated carbide tools. Cutting speeds were set at 100 m/min, the speed typically recommended for conventional turning, and 500 m/min. At 100 m/min, adhesions and subsequent chippings were observed on the cutting edges. Meanwhile, at 500 m/min the higher average temperature at the tool-workpiece contact area caused small wear spots, rather than adhesions at the optimized tool speed. Hence, for rotary cutting, a higher cutting speed is more effective in terms of both achieving several-times-higher productivity and reducing the amount of tool failure due to the difference of tool failure modes.

scholarly journals MATHEMATICAL MODELING OF VERTICAL OSCILLATIONS OF A CUTTING MACHINE FRONTLY MOUNTED ON AN ARABLE-TILL TRACTOR

2021 ◽  
pp. 39-56
Author(s):  
Volodymyr Bulgakov ◽  
Valeriy Adamchuk ◽  
Grigory Kaletnіk ◽  
Ivan Golovach
Keyword(s):  
Differential Equation ◽  
Vibration Amplitude ◽  
Experimental Studies ◽  
Vertical Plane ◽  
Soil Surface ◽  
Design Parameters ◽  
Analytical Determination ◽  
Surface Irregularities ◽  
Rotary Cutting

Experimental studies and production experience show that the most productive and high-quality collection of sugar beet haulms without soil impurities, is possible only when a continuous, carbonless cut of its main mass at the root is carried out. However, the use of haulm toppers with rotary haulm cutters, which are carried out without a guide cut, frontally mounted on energy resources, as well as a significant increase in the working speeds of harvesting, cause intense vibrations of these haulm toppers in the longitudinal-vertical plane, which not only reduces the quality of trimming the heads of root crops, but causes, in general, significant losses of tops. Therefore, there is a need for an analytical determination of the influence of the kinematic and design parameters of a topper, frontally mounted on a wheeled tractor, on the magnitude of the amplitude of oscillations in the longitudinal-vertical plane of its haulm topper. Taking this need into account, in this work we have constructed a computational mathematical model of the movement of a topper front-mounted on a wheeled tractor, based on the use of the original equation of dynamics in the form of Lagrange of the second kind. According to the developed equivalent circuit and the implementation of the necessary mathematical transformations, a nonlinear differential equation was obtained, which describes the oscillations of the rotary cutting device of the topper in the longitudinal-vertical plane when its pneumatic gauge wheels move over the unevenness of the soil surface. According to the compiled program and the numerical solution on the PC of the specified differential equation, rational constructive and kinematic parameters of the topper frontally mounted on the tractor have been determined which reduce the indicated oscillations. So, with the forward speed of movement of the topping unit equal to = 3,0 m∙ s–1, the vibration amplitude of the topper rotor decreases 1,2 ... 1,5 times in comparison with the height of the field surface irregularities, equal to = ± 0.04 m. With the vibration amplitude of the lower ends of the knives of the rotary cutting apparatus up to 4 cm, the loss of haulms does not increase significantly. However, with an increase in the amplitude of these fluctuations to 7 cm and more, the loss of tops increases significantly, the maximum values of which exceed 12%.

Comprehensive Identification of Durability for Selected Cutting Tool Applied on the Base of Taylor Dependence

2013 ◽  
Vol 716 ◽  
pp. 254-260 ◽  
Author(s):  
Anton Panda ◽  
Ján Duplák ◽  
Karol Vasilko
Keyword(s):  
Cutting Tool ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Machining Process ◽  
Technical Science ◽  
Technical Practice ◽  
Comprehensive Information ◽  
Basic Parameters ◽  
Tool Durability

Technical practice uses a lot of cutting tools made of different materials. According to selecting workpiece have to be defined technological conditions. For all selected technological conditions is important prescribe parameters for machining. The basic parameters for every cutting process are cutting speed, feed and cutting depth. These technological conditions are defined by means of calculation or by means of mechanical engineering tables. Specification of tool wear by means of calculation is very difficult. Very important cutting tool property is its durability. Durability of cutting tool defines lifetime of this cutting tool and it determines its suitability for select technological operation. Technical science defines a lot of different factors, that they may be cause of shorter cutting tool lifetime. For increase cutting tool durability is necessary maximally possible elimination of these factors. Determination of cutting tool durability is very important, because provides comprehensive information how to determine appropriate technological conditions for selected cutting tool. In engineering is for determination of cutting tools durability used T-vc dependence. The article describes process how to create the durability dependence for cutting tool made of cutting ceramic (Al2O3) by means of T-vc dependence in machining process of C45.

KINEMATIC FEATURES OF THE LAPPING PROCESS AND DETERMINATION OF ITS BASIC PARAMETERS

2020 ◽  
Vol 7 (3) ◽  
pp. 23-28
Author(s):  
EZIZ SARVAN SHIRVAN ◽  
Keyword(s):  
Dynamic Properties ◽  
Cutting Speed ◽  
Equilibrium System ◽  
Technological Parameters ◽  
Kinematic Characteristics ◽  
Angular Velocities ◽  
Basic Parameters ◽  
Grinding Tool ◽  
Mathematical Relationships ◽  
Analytical Expressions

This paper discusses the kinematic characteristics of lapping process and the main parameters of the process. It was determined that the influencing degree of technological parameters to the forming surface and processes. It was projected the construction of the lapping head for processing of internal cylindrical surfaces, scheme of the lapping operation and graphic description of the forces influencing. The relationships between the axial, radial and tangential cutting forces and the effect of the combined force thereof are determined in order to ensure the necessary surface pressure. During the analysis geometric and mathematical relationships were obtained. The extracted analytical expressions can be realized by further experimental researches and can be used in engineering calculations of technological parameters of processing by lapping. Angular velocity, friction force, linear velocity, also the length of the tactile curve and the radius of the part can be considered the main kinematic and dynamic parameters of the process that the formation of the surface, also the course of the process depends on these parameters. Depending on the kinematic parameters, the wear nature of the tool changes and this changes the linear and angular velocities, which have a significant impact on the accuracy, quality and productivity of processing. When examining the technological capabilities of the process, the nature of the movement between the part and the grinding tool, also changes in cutting speed are often considered as a main factor. Analytical expressions were obtained to determine the main parameters of the process, taking into account the kinematic characteristics of the friction process. These expressions can be used in engineering calculations and allow to determine the optimal values of the processing mode. In order to obtain the required micrometric surface cleanliness and measurement accuracy, correlation relationships were established between the main parameters of the process, equations of the equilibrium system of shear forces were compiled and analytical expressions were obtained based on the analysis of kinematic and dynamic properties of the system.

FRACTIONAL DETERMINATIONS OF URINARY 17-KETOSTEROIDS IN HYPEREMESIS GRAVIDARUM

1962 ◽  
Vol 41 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Pentti A. Järvinen ◽  
Sykkö Pesonen ◽  
Pirkko Väänänen
Keyword(s):  
Hyperemesis Gravidarum ◽  
First Trimester ◽  
Control Group ◽  
Before And After ◽  
Daily Urine ◽  
First Trimester Of Pregnancy ◽  
The Difference

ABSTRACT The fractional determination of 17-ketosteroids in the daily urine was performed in nine cases of hyperemesis gravidarum and in four control cases, in the first trimester of pregnancy both before and after corticotrophin administration. The excretion of total 17-KS is similar in the two groups. Only in the hyperemesis group does the excretion of total 17-KS increase significantly after corticotrophin administration. The fractional determination reveals no difference between the two groups of patients with regard to the values of the fractions U (unidentified 17-KS), A (androsterone) and Rest (11-oxygenated 17-KS). The excretion of dehydroepiandrosterone is significantly higher in the hyperemesis group than in the control group. The excretion of androstanolone seems to be lower in the hyperemesis group than in the control group, but the difference is not statistically significant. The differences in the correlation between dehydroepiandrosterone and androstanolone in the two groups is significant. The high excretion of dehydroepiandrosterone and low excretion of androstanolone in cases of hyperemesis gravidarum is a sign of adrenal dysfunction.

DETERMINATION OF CUTTING SPEED VALUES FOR PROCESSING A NON-RIGID SHAFT

THE BULLETIN ◽  
2020 ◽  
Vol 4 (386) ◽  
pp. 27-33
Author(s):  
Zh. N. Shakenova ◽  
◽  
◽  
Keyword(s):  
Cutting Speed

THE SUBJECT FIELD OF INSTITUTIONAL EDUCATION: THE SENSE AND PROSPECTS OF DEVELOPMENT IN UKRAINE

2020 ◽  
pp. 25-38
Author(s):  
Irina Mordous
Keyword(s):  
Decisive Role ◽  
Subject Field ◽  
National Education ◽  
Progressive Development ◽  
Separate Area ◽  
Economic Transformations ◽  
The Difference ◽  
The Individual ◽  
Political Economic

The development of modern civilization attests to its decisive role in the progressive development of institutions. They identified the difference between Western civilization and the rest of the world. Confirmation of the institutional advantages of the West was its early industrialization. The genesis and formation of institutionalism in its ideological and conceptualmethodological orientation occurs as a process alternative to neoclassic in the context of world heterodoxia, which quickly spread in social science. Highlighting institutional education as a separate area of sociocultural activity is determined by the factor of differentiation of institutional theory as a whole. A feature of institutional education is its orientation toward the individual and his/her transformation into a personality. The content of institutional education is revealed through the analysis of the institution, which includes a set of established customs, traditions, ways of thinking, behavioral stereotypes of individuals and social groups. The dynamics of socio-political, economic transformations in Ukraine requires a review of the foundations of national education and determination of the prospects for its development in the 21st century in the context of institutionalism.

scholarly journals Effect of tillage, slope, and rainfall on soil surface microtopography quantified by geostatistical and fractal indices during sheet erosion

2020 ◽  
Vol 12 (1) ◽  
pp. 232-241
Author(s):  
Na Ta ◽  
Chutian Zhang ◽  
Hongru Ding ◽  
Qingfeng Zhang
Keyword(s):  
Surface Roughness ◽  
Fractal Dimension ◽  
Soil Surface ◽  
Rainfall Events ◽  
Tillage Practices ◽  
Surface Microtopography ◽  
Artificial Rainfall ◽  
Soil Surface Roughness ◽  
The Difference ◽  
Sheet Erosion

AbstractTillage and slope will influence soil surface roughness that changes during rainfall events. This study tests this effect under controlled conditions quantified by geostatistical and fractal indices. When four commonly adopted tillage practices, namely, artificial backhoe (AB), artificial digging (AD), contour tillage (CT), and linear slope (CK), were prepared on soil surfaces at 2 × 1 × 0.5 m soil pans at 5°, 10°, or 20° slope gradients, artificial rainfall with an intensity of 60 or 90 mm h−1 was applied to it. Measurements of the difference in elevation points of the surface profiles were taken before rainfall and after rainfall events for sheet erosion. Tillage practices had a relationship with fractal indices that the surface treated with CT exhibited the biggest fractal dimension D value, followed by the surfaces AD, AB, and CK. Surfaces under a stronger rainfall tended to have a greater D value. Tillage treatments affected anisotropy differently and the surface CT had the strongest effect on anisotropy, followed by the surfaces AD, AB, and CK. A steeper surface would have less effect on anisotropy. Since the surface CT had the strongest effect on spatial variability or the weakest spatial autocorrelation, it had the smallest effect on runoff and sediment yield. Therefore, tillage CT could make a better tillage practice of conserving water and soil. Simultaneously, changes in semivariogram and fractal parameters for surface roughness were examined and evaluated. Fractal parameter – crossover length l – is more sensitive than fractal dimension D to rainfall action to describe vertical differences in soil surface roughness evolution.

scholarly journals Possibility of Human Gender Recognition Using Raman Spectra of Teeth

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3983
Author(s):  
Ozren Gamulin ◽  
Marko Škrabić ◽  
Kristina Serec ◽  
Matej Par ◽  
Marija Baković ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Principal Component ◽  
Support Vector ◽  
Gender Recognition ◽  
Proof Of Concept ◽  
Male And Female ◽  
Tooth Type ◽  
Tooth Apex ◽  
The Difference

Gender determination of the human remains can be very challenging, especially in the case of incomplete ones. Herein, we report a proof-of-concept experiment where the possibility of gender recognition using Raman spectroscopy of teeth is investigated. Raman spectra were recorded from male and female molars and premolars on two distinct sites, tooth apex and anatomical neck. Recorded spectra were sorted into suitable datasets and initially analyzed with principal component analysis, which showed a distinction between spectra of male and female teeth. Then, reduced datasets with scores of the first 20 principal components were formed and two classification algorithms, support vector machine and artificial neural networks, were applied to form classification models for gender recognition. The obtained results showed that gender recognition with Raman spectra of teeth is possible but strongly depends both on the tooth type and spectrum recording site. The difference in classification accuracy between different tooth types and recording sites are discussed in terms of the molecular structure difference caused by the influence of masticatory loading or gender-dependent life events.

scholarly journals Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 666
Author(s):  
Guilin Han ◽  
Anton Eisenhauer ◽  
Jie Zeng ◽  
Man Liu
Keyword(s):  
Soil Depth ◽  
Isotope Composition ◽  
Soil Surface ◽  
Natural Soil ◽  
Calcium Isotope ◽  
Karst Forest ◽  
Content Ratio ◽  
The Difference ◽  
Preferential Uptake ◽  
Vital Factor

In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.

Sign in / Sign up

Export Citation Format

Share Document