On the Resolution of Compositional Datasets into Convex Combinations of Extreme Vectors

<p>Large compositional datasets of the kind assembled in the geosciences are often of remarkably low approximate rank. That is, within a tolerable error, data points representing the rows of such an array can approximately be located in a relatively small dimensional subspace of the row space. A physical mixing process which would account for this phenomenon implies that each observation vector of an array can be estimated by a convex combination of a small number of fixed source or 'endmember' vectors. In practice, neither the compositions of the endmembers nor the coefficients of the convex combinations are known. Traditional methods for attempting to estimate some or all of these quantities have included Q-mode 'factor' analysis and linear programming. In general, neither method is successful. Some of the more important mathematical properties of a convex representation of compositional data are examined in this thesis as well as the background to the development of algorithms for assessing the number of endmembers statistically, locating endmembers and partitioning geological samples into specified endmembers. Keywords and Phrases: Compositional data, convex sets, endmembers, partitioning by least squares, iteration, logratios.</p>

On the Resolution of Compositional Datasets into Convex Combinations of Extreme Vectors

<p>Large compositional datasets of the kind assembled in the geosciences are often of remarkably low approximate rank. That is, within a tolerable error, data points representing the rows of such an array can approximately be located in a relatively small dimensional subspace of the row space. A physical mixing process which would account for this phenomenon implies that each observation vector of an array can be estimated by a convex combination of a small number of fixed source or 'endmember' vectors. In practice, neither the compositions of the endmembers nor the coefficients of the convex combinations are known. Traditional methods for attempting to estimate some or all of these quantities have included Q-mode 'factor' analysis and linear programming. In general, neither method is successful. Some of the more important mathematical properties of a convex representation of compositional data are examined in this thesis as well as the background to the development of algorithms for assessing the number of endmembers statistically, locating endmembers and partitioning geological samples into specified endmembers. Keywords and Phrases: Compositional data, convex sets, endmembers, partitioning by least squares, iteration, logratios.</p>

Effects of fertilizer under different dripline spacings on summer maize in northern China

Maximizing grain yields with effective fertilization technologies and minimizing nitrogen losses is essential in agroecosystems. In this research, we conducted a two-year field experiment to explore whether dripline spacing and fertilization rate would affect maize grain yield. Two dripline spacings (i.e., one drip line per row of maize with a row space of 60 cm and one drip line per two rows of maize) and two fertilization rates (i.e., high fertilization level: N, 180 kg ha−1; P2O5, 90 kg ha−1; and K2O, 90 kg ha−1 and low level: N, 139.5 kg ha−1; P2O5, 76.5 kg ha−1; and K2O, 76.5 kg ha−1) were employed in this research. The results showed that maize yield was significantly affected by both dripline spacing and fertilization rate. The maize yield was 10.2% higher in the treatment with one drip line per two rows than that in the treatment with one drip line per row. Maize yield increased by 10.9% at the high fertilization level compared to that at the low fertilization level. The quantity of cumulative ammonia volatilization was reduced by 15.1% with one drip line per two rows compared to that with one drip line per row, whereas it increased by 26.9% at the high fertilization level compared with that at the low fertilization level. These results indicated that one drip line per two rows with a high fertilization rate increased the yield and could reduce the environmental burden, which may be economically beneficial and environmentally sound for maize fertigation for green agricultural development.

A Wind Tunnel Simulation of Windproof Effectiveness of Simulated Shrubs with Different Spatial Configurations

&lt;p&gt;A better understanding of the distribution of the airflow field and wind velocity around the simulated shrubs is essential to provide optimized design and maximize the efficiency of the windbreak forests. In this study, a profiling set of Pitot Tube was used to measure the airflow field and wind velocity of simulated shrubs by wind tunnel simulation. The effects of form configurations and row spaces of simulated shrubs on windproof effectiveness were in-depth studied. We come to the following results: The weakening strength to wind velocities of hemisphere-shaped and broom-shaped shrubs at 26.25 cm was mainly concentrated below 2 cm near the root and 6-14 cm in the middle-upper part, while the spindle-shaped shrubs were at 0.2-14 cm above the canopy, which meant the windproof effect of spindle-shaped shrubs was was better than that of hemisphere-shaped and broom-shaped. With the improvement of row spaces, the weakening height to wind velocities of the hemisphere-shaped shrubs at 35 cm was only concentrated below 2 cm near the root exclude for the 6-14 cm at 26.25 cm, which presented the hemisphere-shaped shrubs were not suitable for the layout of wide row space. Further, the form configurations of simulated shrubs had a stronger influence on wind velocity than row spaces. Moreover, the designed windbreaks with &lt;em&gt;Nitraria tangutorum&lt;/em&gt;, which more effectively reduced the wind velocity among the windbreaks compared to behind the windbreaks. In the wind control system, the hemisphere-shaped windbreaks should be applied as near-surface barriers, and the windbreaks of broom-shaped and spindle-shaped can be used as shelterbelts above the near-surface. These analytical findings&amp;#160;offer theoretical guidelines on how to arrange the windbreak forests for preventing wind erosion in the most convenient and efficient ways.&lt;/p&gt;

Plum (Prunus domestica L.) intense orchards in the Ukraine's Lisosteppe

The authors present the results of studying different types of the plum orchards. The trees grafted on the clonal rootstocks VVA-1 and Evryca appeared to take roots best in spring after planting. The trees on those rootstocks began active growth two weeks earlier than on seed rootstock (myrobalan plum) and formed a greater amount of the side shoots. In the second-fifth years after planting the trees on the medium-growing rootstock Evryca grew more actively, on VVA-1 more slowly. The most intensive was the formation of the flattened crowns of the trees grafted on Evryca when in the three-year age the time expenditures were by twice higher than on the other rootstocks. The cultivar Stanley on the clonal rootstocks was the most early-ripening one. Its orchards began marketable fruit-bearing in the three years age. The trees of more vigorous cvs up to the five-year age were lower by a quarter on VVA-1 and of the low variety Oda higher on the seed rootstock and on Evryca and VVA-1 lower by 15 and 33 % respectively. It appeared that it is necessary to limit crowns from the side of the inner-row space for the trees on Evryca beginning from the five-year age. The trees of all the strains had the largest summary shoot length on the myrobalan plum: Oda by 1.5, Stanley by 1.4-2.9, Bogatyrska by 3.3-3.4 times than on VVA-1 and by 1.2; 1.9 and 3.8 times respectively than on Evryca. The trunk diameter of the trees on VVA-1 was by 33-62 % shorter than on the other rootstocks. In the first years of the marketable fruit-bearing the trees of ‘Stanley’ and ‘Oda’ with the orbicular crown on the seed rootstock were more productive (38.4 and 35.9 kg/tree) while on Evryca this index was by 22 % lower. The trees on VVA-1 provided the yield on a level of 31-48 % of that on the myrobalan plum. Since the orchards on different rootstocks were established with the different planting density the highest yield on the whole was achieved in the orchards of cvs Stanley and Oda on Evryca with the orbicular crown (4 x 2.5 m) on the average 297.5 and 278.8 c/ha respectively, that is by 1.4 times more than on the seed rootstock and VVA-1 with the formation of the spindle-like crown (by 1.2-1.3 times higher). The planted crowns on the trees on VVA-1 proved non-effective.

On soil and technological conditions impact on the parameters of soil moisture zones formed with drip irrigation of tree-fruit crops

Purpose: development of a graphic-analytical method for assessing the effect of soil conditions on moisture contours size formed during drip irrigation to select the parameters of drip modules for irrigating tree-fruit plants cultivated in garden plantations. Materials and methods: the planned dimensions of moisture contours of sub-drip soil space are taken as indicators for assessing and determining the parameters of irrigation modules for drip irrigation of row planted tree-fruit crops from along-row traced irrigation pipelines. When analyzing the parameters and location of moisture zones, the layout of plants in a garden with a distance between trees in a row equal to 2 m was considered, with a different number of drip emitters on the drip line within the inter-tree area. Results: using the author's dependence, the diameters and areas of moisture contours formed during drip irrigation in southern medium-thick chernozems were determined. For typical schemes for placing drip emitters along a row of traced drip lines that provide soil moistening in the undercrown space of fruit plants, moisture contours formed during drip irrigation are built. The obtained geometric parameters of moisture zones for different patterns of irrigation lines, characterized by different inter-emitters distances and different numbers and locations of drip emitters, are compared with the area of plant nutrition. Based on the results of comparing the areas of moisture zone and the zone of plant root systems distribution, a high degree of locality of the wetted space was noted. Conclusions: the graphic images and quantitative characteristics of drip moisture zones in the undercrown along the row space of plants created using the proposed graphic-analytical method allow assessing the state of its moisture content and making a decision on the parameters and schemes of the irrigation module for certain soil and technological conditions of the garden plantation.

IMPROVING SEED AND OIL YIELD OF SUNFLOWER (Helianthus annuus L.) BY USING DIFFERENT INTER AND INTRA ROW SPACE COMBINATIONS

The aim of this study was to determine the appropriate inter and intra row spacing of sunflower irrigated during the critical growing stages to obtain the highest seed and oil yields. The experiment was carried out with three replications in the randomized blocks with split plots design in 2016 and 2017. Inter row spacings (45 and 70 cm) were placed on the main plots and intra row spacings (20, 25, 30, 35 and 40 cm) were placed on the subplots. Bosfora, oilseed hybrid sunflower variety was used as plant material. It has been determined that inter and intra row spaces had statistically significant effects on sunflower development and yield parameters. In general, as the distance between the inter and intra rows narrowed, plant height was increased, while the stem and table diameters, the number of seeds in the table, thousand seed weight, oil rate and per plant yield were decreased. And also seed and oil yield was increased, in contrast to per plant yield, due to the increase in plant number per unit area. Seed and oil yield with 45x25 cm inter and intra row spacings were 59.6% and 52.9% higher as compared to 70x40 cm spacing, respectively. The highest seed and oil yield was obtained from 45x25 cm inter and intra row space under irrigated conditions

MULTIVARIABLE ANALYSIS OF CHARACTERS AFFECTING YIELD IN CHICKPEA PLANTS

The aim of this study was to determine the appropriate inter and intra row spacing of sunflower irrigated during the critical growing stages to obtain the highest seed and oil yields. The experiment was carried out with three replications in the randomized blocks with split plots design in 2016 and 2017. Inter row spacings (45 and 70 cm) were placed on the main plots and intra row spacings (20, 25, 30, 35 and 40 cm) were placed on the subplots. Bosfora, oilseed hybrid sunflower variety was used as plant material. It has been determined that inter and intra row spaces had statistically significant effects on sunflower development and yield parameters. In general, as the distance between the inter and intra rows narrowed, plant height was increased, while the stem and table diameters, the number of seeds in the table, thousand seed weight, oil rate and per plant yield were decreased. And also seed and oil yield was increased, in contrast to per plant yield, due to the increase in plant number per unit area. Seed and oil yield with 45x25 cm inter and intra row spacings were 59.6% and 52.9% higher as compared to 70x40 cm spacing, respectively. The highest seed and oil yield was obtained from 45x25 cm inter and intra row space under irrigated conditions.

Narrow and twin-row plantings do not increase maize yield

Reducing row space and sowing in twin rows of maize (Zea mays L.) allow more equidistant plant distribution at the same density. The objective of this research was to evaluate the effect of these two management practices on the nitrogen content of the index leaf, the leaf area index at silking, and the grain yield of maize at different plant densities. The experiment was carried out in Lages, Santa Catarina State University, in southern Brazil during the growing seasons 2016-2017 and 2017-2018. A split-plot arrangement of a randomized complete block design was used. Two plant densities (7 and 9 plants m-2) were distributed in the main plot, and five row spaces (0.4, 0.6, 0.8, 1.0 m and twin rows 0.6 m apart with 0.18 m between rows) were evaluated in split-plots. Physiological traits and grain yield were determined on the maize hybrid P30R50YH. The experiments were sown on 10/20/2016 and 10/21/2017. Kernel yields were higher at the plant density of 9 plants m-2 than at 7 plants m-2. The row space did not affect the nitrogen content of the index leaf, the crop leaf area index at silking, and the maize grain yield. The increment of plant density was more effective than the use of narrow and twin rows to enhance P30R50YH hybrid grain yield.

DESCRIPTION OF THE PROCESS OF MOVEMENT OF A MATERIAL PARTICLE IN THE INTER-ROW SPACE OF A DISINTEGRATOR WITH A CHANGING INTER-ROW DISTANCE

Currently, disintegrators are one of the types of equipment used for grinding and mixing various materials. The advantages of disintegrators are the ability to control the speed of rotation of the rotors and change the geometric parameters to obtain a grinding product with the desired grain composition, as well as the simplicity of the design. In this paper, as a result of theoretical research, analytical expressions and are obtained, which define the radial size between adjacent rows of impact elements of the grinding chamber with a periodically varying distance. This change in the radial size has a high-frequency character, which determines the destruction of material particles under the influence of tangential stresses arising in them. To perform the necessary transformations, the article presents a design scheme of the disintegrator grinding chamber with a changing radial distance between adjacent rows. In the inter-row space, due to the inequality of the circumferential velocities of moving particles, tangential stresses acting on these particles occur. According to the result of, the value of tangent stresses in the inter-row space depends on the circumferential velocity of the particle, the coefficient of pseudo-viscous flow grinding and the value of the inter-row distance. The value of the row spacing, due to its periodic nature, can be represented as a function of the amplitude of the change in this distance and the angle measured from the initial direction of the axis. By solving a first-order differential equation with separable variables, it is possible to determine the initial and final value of the particle velocity in the region (0 ≤φ≤ /2) of an inter-row space of variable cross-section. The destruction of a material particle in an area with a periodically changing distance will be carried out if the change in the kinetic energy of the particle exceeds the work on its destruction as a result of collision.