Potential of the physical and chemical characteristics of prickly pear (Opuntia albicarpa Seheinvar var. Villanueva) seeds in agroindustrial processes

Objective: To verify the physical attributes and assess the chemical quality from prickly pear’s seeds (Opuntia albicarpa Seheinvar cv. Villanueva), including seeds´ size, internal friction, external friction, performance for size reduction, sieving and electric conductivity, soluble protein, total protein, phosphorous, carbohydrates, amount of oil and minerals. Design/methodology/approach: To verify and compare the physical attributes and chemical parameters using proved and reliable techniques, to explore their impacts on its future potential, when seeds are intended to agro-industrial processes, considering; its size and quality of space storage and their effect when interacting with handling apparatus and the material they are manufactured with. Results: Selected groups of 100 seeds from four consecutive prickly pears harvests had no differences. While for their chemical analysis, seeds were milled and their revised chemical compounds showed differences between harvest, therefore, drought, management and crop protection significantly affect those attributes. The factors were not included in this study. Limitations on study/implications: Prickly pears are harvested for 4 months per year. This reduces the availability of raw material from other varieties and from other regions, to expand this study and to compare between diverse parameters. Findings/conclusions: There were not significant differences in seed size (wide, large, thickness), external friction and electric conductivity; therefore, handling equipment does not need specifications. While, for the internal friction and all chemical compounds analyzed from seeds´ flour, significate differences were quantified. The latter means that, it is adequate to homogenize these parameters by using other compounds in the agrifood processes.

Analysis of the physical properties of spindle seeds for seed sorting operations

The relationships between the basic physical properties of seeds of selected spindle species were evaluated for the needs of seed sorting operations. Physical properties were measured in the seeds of five spindle species, and the presence of relationships between these attributes was determined in correlation and regression analyses. The average values of the evaluated parameters were determined in the following range: terminal velocity—from 9.2 to 10.3 m s−1, thickness—from 2.57 to 3.26 mm, width—from 2.87 to 3.74 mm, length—from 3.94 to 5.52 mm, angle of external friction—from 20.7° to 24.6°, mass—from 16.5 to 33.8 mg. Spindle seeds were arranged in the following ascending order based on their geometric mean diameter: winged spindle, Hamilton’s spindle, large-winged spindle, broadleaf spindle and European spindle. Spindle seeds should be separated in a sieve equipped with at least two mesh screens with slotted apertures. Depending on the processed spindle species, aperture size should range from ≠ 2.7 to ≠ 3.5 mm in the top screen, and from ≠ 2.4 to ≠ 3.0 mm in the bottom screen.

Study of the dynamics of the coefficient of external friction of seeds crops with shell

The article is devoted to the study of the coefficients of external friction of grain agricultural products-friction in static and dynamic modes, as the most important physical and mechanical characteristics of bulk materials. The description of carousel laboratory unit, program, methodology and results of studies on the practical determination of the coefficients of external friction for typical agricultural grain products according to the materials typical of the working bodies of the production machines. As a result of the research, it was found that in the range of linear velocities from 0 to 1.75 m/s, there is a change in the friction coefficients, which has a nonlinear character.

Mathematical modeling of single action pressing of powder materials under dry friction conditions

The paper presents a theoretical analysis of the single action pressing of powder materials featuring plasticity and compressibility. It takes into account dry external friction between the die material and side walls, which determines the strong nonlinearity of the problem considered. This problem has a number of features that complicate its numerical solution: the presence of external friction, the elastic-plastic law of material behavior description, as well as the calculation of large displacements and, as a consequence, strong geometric nonlinearity. To consider these features, a combination of Fleck–Kuhn–McMeeking and Gurson– Tvergaard–Needleman models was used to consider a wide range of changes in the porosity of materials. The numerical solution of the problem was carried out using finite element analysis with isoparametric elements. The increment of plastic deformations at each step was determined from nonlinear equations of plastic flow. Stresses at the Gaussian points were updated according to the specified increments of deformations to calculate the material behavior during deformation. Unknown density and strain values as functions of coordinate and time were calculated. The influence of the different height-to-diameter ratio of the blank and the value of external friction of the material stress-strain state and compaction kinetics were considered. The distribution of equivalent stresses and the value of volumetric plastic deformations in the material, as well as the nonuniformity of relative density at the end of the pressing period were studied. The theoretical analysis made it possible to study the basic compaction kinetics laws for powder materials with nonuniform density under conditions of dry friction on side walls. The results obtained are relevant for predicting possible negative changes in the blank geometry when implementing the single action pressing scheme for powder materials.

Micro-mechanical prediction of the effect of surfactant concentration and external friction on the visco-elasto-plastic response of an aqueous foam

The present model predicts rheological response of dry aqueous foam, including as a novelty the dissipative effects at the interface.

Dynamic friction coefficients of grain crops of bulk agricultural products

The article covers issues related to the study of physical and mechanical characteristics of bulk materials, namely the coefficients of external friction in static and dynamic modes. The program, methodology and results of research on the practical study of external friction coefficients of typical agricultural grain products by the surfaces made of materials typical for the working bodies of production machines, using an innovative carousel-type device, are presented. As a result of research, it was found that in the range of linear speeds from 0 to 1.75 m/s, there is a change in the friction coefficients, which has a nonlinear character.

MODELING OF EXTERNAL FRICTION COEFFICIENTS OF OILSEED MATERIAL IN THE EXTRUSION IN THE AUGER PRESS

Исследовано внешнее трение масличного материала процесса экструдирования в шнековом прессе. Использован метод математического моделирования вязкопластичного течения для описания процесса экструдирования. Определены коэффициенты внешнего трения масличного материала процесса экструдирования по каналу В от 0,342 до 0,349 и по корпусу З от 0,384 до 0,377 при частоте вращения шнека NВ от 1,571 до 2,827 Гц соответственно. Установлена необходимость использования теоретически обоснованной модели вязкопластичного течения в канале экструдера. Показана возможность использования этих параметров процесса экструдирования для увеличения пропускной способности загрузочных витков маслоотжимных агрегатов. The external friction of the oilseed material of the extrusion process in the screw press is investigated. The method of mathematical modeling of viscoplastic flow is used to describe the extrusion process. The coefficients of external friction of the oilseed material of the extrusion process along the channel В from 0,342 to 0,349 and the body Z from 0,384 to 0,377 at the speed of rotation of the screw NВ from 1,571 to 2,827 Hz, respectively. The necessity of using a theoretically grounded model of viscoplastic flow in the extruder channel is established. The possibility of using these parameters of the extrusion process to increase the capacity of the loading coils of oilpumping units is shown.