Maize stalk stiffness and strength are primarily determined by morphological factors

The maize (Zea mays) stem is a biological structure that must balance both biotic and structural load bearing duties. These competing requirements are particularly relevant in the design of new bioenergy crops. Although increased stem digestibility is typically associated with a lower structural strength and higher propensity for lodging, with the right balance between structural and biological activities it may be possible to design crops that are high-yielding and have digestible biomass. This study investigates the hypothesis that geometric factors are much more influential in determining structural strength than tissue properties. To study these influences, both physical and in silico experiments were used. First, maize stems were tested in three-point bending. Specimen-specific finite element models were created based on x-ray computed tomography scans. Models were validated by comparison with experimental data. Sensitivity analyses were used to assess the influence of structural parameters such as geometric and material properties. As hypothesized, geometry was found to have a much stronger influence on structural stability than material properties. This information reinforces the notion that deficiencies in tissue strength could be offset by manipulation of stalk morphology, thus allowing the creation of stalks which are both resilient and digestible.

EXAMINATION OF THE QUALITY OF NANOMATERIALS IN THE DEVELOPMENT AND APPLICATION OF CIRCULATING RESOURCES IN CONSTRUCTION

the advantage of the equality indicator is the relative simplicity of definition and the possibility of periodic moni-toring. According to the equality indicator, it is possible to assign repairs and predict the service life, assess the condition of the road surface. Experimental studies have proved that there is a connection between the evenness of the coating and the strength of the pavement, which opens up the possibility of determining the structural strength of non-rigid pavement, which provides a given evenness of the coating for the last year of operation be-fore major repairs. The question of assessing the impact of the unevenness of the road surface on the processes of development and accumulation of deformations, changes in the evenness of the coating during operation remain largely open. This is due to the multifactorial nature of the problem of predicting the equality of coverage, so it is advisable to use approaches based on direct measurement methods. Most of the existing models of interaction of a pneumatic or rigid wheel with a coating are designed for problems of pavement mechanics or car theory, therefore they cannot be unambiguously applied to determine the value of the dynamism coefficient. A significant disad-vantage of these solutions is insufficient consideration of the deformative properties (modulus of elasticity) of the pavement.

Self-healing efficiency study of thermoset-thermoplastic polymer material

This study is focused on exploring intrinsic self-healing polymer material development, where the inclusion of thermoplastic additives into thermoset polymer material as healing agents. Intrinsic self-healing thermoset-thermoplastic development is involving the material formulation of thermoset liquid resin (Poly Bisphenol A-co-epichlorohydrin) and thermoplastic (polycaprolactone). The material formulation ratio is up to 30% polycaprolactone with respect to thermoset weight. The mixture is heated and stirred to saturate at 80°C before the hardener is added. The mixture is cured and further finishing as Charpy impact test specimen. The specimen is fractured and absorbed impact energy property characterised through the Charpy impact test. The heat treatment is then performed to trigger the self-healing reaction in the polymer. The self-healing efficiency of the thermoset thermoplastic is investigated based on the absorbed impact energy before and after the heat treatment. The 20% or higher thermoplastic concentration in the polymer caused the polymer to possess high self-healing efficiency and faster healing time as compared to the low thermoplastic concentration polymer. However, the high concentration polymer has a disadvantage on the overall structural strength instead. On the contrary, 10% to 15% thermoplastic composition will result in lower and slower self-healing performance but higher initial structural strength.

The structure of trees.

Trees are, by definition, the tallest land plants. To grow tall over multiple years they must solve several problems: structural strength; carbohydrate and nutrient storage capacity to survive and regrow after periods of stress; and conductive capacity for water, carbohydrates and nutrients must be increased/renewed over time to keep pace with increases in canopy size. Additionally, apical meristems must be capable of surviving through periods of stress (especially over winter or during drought). Structural strength, storage capacity and water, carbohydrate and nutrient conductive capacity are provided by cells derived from a sheath of meristematic cells (vascular cambium) that surround the body of trees (shoots, stems, branches, trunk, perennial roots). This chapter describes the structure of fruit trees.

A comparative analysis of the stress-strain state of disc specimens in assessing the structural strength of materials

A study of the stress-strain state (SSS) of disc specimens has been conducted when testing specimens with stress concentrators (grooves). The research has shown that the truncation of circular discs along two symmetrical chords makes it possible to change the type (the ratio of principal stresses) of SSS that occurs at the destruction site. Therefore, these specimens can be used to assess the structural strength of materials on standard single-drive testing machines, taking into account the real type of SSS that occurs in the bearing elements of machines. The results of numerical SSS modeling have been used to build the dependences of the SSS type and level on geometric parameters of specimens. Geometrical parameters can be chosen for a certain SSS type to assess both the static and fatigue strengths of materials used in the manufacture of bearing elements.

Research on Structural Design and Parametric Modeling of Trestle of Material Ropeway of Transmission Line

Aiming at the trestle of material ropeway of transmission line, the structural design of components was carried out with the combination of 3D design software. Parametric modeling method was adopted to carry out the modeling of components with different structural parameters. The stress status of components of trestle was analyzed, the design load of components was proposed, and the strength of the designed components was checked through finite element simulation analysis. The results show that the components can meet the requirements of structural strength. The proposed method can realize parametric modeling of solid model and effectively improve the design efficiency of material ropeway.

Application of knockdown technology for wooden bow arch bridges

The use of wood as a construction material for simple bridges has begun to be abandoned and switch to concrete or steel bridges with considerations of durability and structural strength. However, from an ecological perspective, wood is still the most renewable material by nature itself. Returning to ecologic natural materials is an issue of the United Nation that needs to be supported by educational institutions. This community service begins with determining the span and height of the bridge, followed by planning and calculating the strength of the material. The parts of the bridge are manufactured in the workshop of the Civil Engineering Department, Samarinda State Polytechnic. The assembly and erection processes are carried out in the field. The uniqueness of this program is in the application of the wooden arc bridge model with a raft unloading system by presenting an attractive aesthetic, so that it is hoped that it can again become an option in determining the type of bridge for users.

Improving the productivity of Pini-Kay fuel briquettes by modernizing the working part of the PSH-250 press

The research related to the productivity of production of fuel briquettes of the "Pini-Kay" type, due to the modernization of the working part of the press line for the production of fuel briquettes with a capacity of 250 kg / h (LVB - 250) was carried out. It is known that the press used on this line is PSH-250, it is the main working equipment of this line, as it serves to press the briquette under temperature and is the closing link in the whole briquette process. In the presented study, the main criterion of productivity was considered to be the number of manufactured products before the break of the splined auger, because the breakdown forces to stop the equipment and replace it. This in turn reduces the number of manufactured products. The paper states that the modernization was carried out as follows: the slot screw, which is the main working body of the press PSH - 250, made of structural steel (steel 45) by casting, was replaced by a slotted screw made by machining on CNC machines, high-quality structural alloy steel 40HMFA. This steel is used to make splined shafts, connecting rods and rods, and is best suited for making a splined auger. In addition, to increase the structural strength, the workpiece of the auger, was made heat treatment - normalization. The proposed technological solution allowed to increase the productivity of fuel briquettes, by reducing the downtime of equipment for repair and replacement of working parts of the press PSH-250. This in turn reduced the company's financial costs for spare parts and affected the cost of finished products. The obtained results show that the slotted augers proposed by the authors allowed to increase the productivity of fuel briquettes production almost 10 times in comparison with the previous results.