Maximum Admissible Slip of Tractor Wheels without Disturbing the Soil Structure

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, . 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 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 , 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 , 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.

Evaluating diameter distribution series of small-leaved lime (Tilia cordata Mill.) in forest stands

Background The paper provides studies on the structure of planted small-leaved lime (Tilia cordata Mill.) in the conditions of the Bashkir Cis-Urals. This work aimed to analyze their assortment by diameters and compile appropriate tables. This is the first study of lime for this region. The results of the study are based on data from 69 temporary sample plots. Stands are represented by trees of 11–79 years old, not affected by thinning. They belong to the I–III growth classes and the most common goutweed forests. Results It was found, that small-leaved limes have a specific structure—coefficient of diameter variation in stands decreases with a higher average diameter, reaching 26 and 16% at 28 cm with thin and dense initial planting, respectively. The variability of tree diameters is related to the average stand diameter and is due to the initial density of the grown plantations. Correlations between the coefficients of asymmetry and excess with age and the average diameter was revealed. Conclusions The verification of theoretically calculated frequencies of distribution series to empirically observed frequencies showed a discrepancy in 29 and 19% of the total number, respectively. For the remaining series of distributions, the scale and shape parameters of the Weibull function were modeled using the average, minimum and maximum diameters, standard deviation, coefficients of asymmetry and excess. This made it possible to develop stand tables for small-leaved limes depending on the average diameter.

Evolution of Cooperation for Multiple Mutant Configurations on All Regular Graphs with N ≤ 14 Players

We study the emergence of cooperation in structured populations with any arrangement of cooperators and defectors on the evolutionary graph. In a computational approach using structure coefficients defined for configurations describing such arrangements of any number of mutants, we provide results for weak selection to favor cooperation over defection on any regular graph with N ≤ 14 vertices. Furthermore, the properties of graphs that particularly promote cooperation are analyzed. It is shown that the number of graph cycles of a certain length is a good predictor for the values of the structure coefficient, and thus a tendency to favor cooperation. Another property of particularly cooperation-promoting regular graphs with a low degree is that they are structured to have blocks with clusters of mutants that are connected by cut vertices and/or hinge vertices.

The Study of Refractive–Index Structure Coefficient Behavior Derived from Two Weather Stations at Baghded City

Refractive –Index Structure Coefficient c_µ^2 behavior derived between horizontal points over at Baghded city was studied during the days containing different weather conditions where we used a horizontal relation to calculate c_µ^2 between two points where we considered the first point Al-Mustansiyah university and the second point Iraqi Meteorological Organization and Seismic Monitoring (IMOSM). This provided us with data from the automatic weather station installed mounted near (ASB) the height of 4m and the second station was set at a height of 2m. The data recorded were pressure and temperature where we calculated the relationship between the different rates of temperature and distance between the two stations where the distance is 20 km. For the heat of C_(T )^(2 )which when finding its value, the value of C_(µ.)^2 and the period was several days represented by a group of atmospheric phenomena and these days are rainy and foggy and clear sky data taken by what was available from measurement at the station. A relationship was found between C_(µ.)^2. With time and also with temperature and atmospheric pressure and difference in temperature for each hour.

Physicochemical Principles of Synthesis and Modification of Unsaturated Polyester-Polyvinyl Chloride Composites and the Properties of Materials Derived from Them

The influence of the polymeric modifier of polyvinyl chloride on the structuring of unsaturated polyester resins has been investigated. It is established that the introduction of 2–5 parts by weight of polyvinyl chloride into a polyester composite accelerates the process of gelation and shortens the time of microgelation of the polyester. The influence of polyvinyl chloride on the structure coefficient, surface hardness, and strength of adhesive bonds and technological shrinkage of modified polyester composites has been revealed.