RESEARCH ON THE UNIFORMITY DEGREE OF SOLID ORGANIC FERTILIZERS DISTRIBUTION

In this paper are presented the results of experimental research conducted in order to improve the uniformity of organic fertilizers distribution (compost and semi-fermented manure) used for soil fertilization, if the administration is done with a machine with a distributor with continuous spiral centrifugal beaters, arranged vertically. The uniformity of organic fertilizers distribution depends on a number of factors such as: the speed and angle of inclination of the distribution device, the distance between the distribution beaters, the humidity and the density of the material, wind speed, the size of the fertilizer particles. The determinations were performed under working conditions and the various parameters were the beaters speed, beaters inclination angle and the feed rate of the distribution device, choosing 3 situations (minimum, average and maximum) for each of them. Based on the obtained results, the multivariable functions of polytropic form was determined, which characterize the degree of uniformity of the spread material, function that can be the basis for the elaboration of constructive solutions to ensure the optimum uniformity of distribution.

A Simplified Stress Analysis of Functionally Graded Beams and Influence of Material Function on Deflection

This paper aims at providing a simplified analytical solution for functionally graded beam stress analysis and optimized material gradation on the beam deflection. The power-law (P-FGM) and exponential (E-FGM) material functions were considered for an exact solution of the normal and shear stress distributions across the beam thickness. Optimization of material function on the FGM beam deflection, which is new of its kind, was also investigated considering both simply supported and cantilever beams. It was observed that the non-dimensional normal stress and shear stress are independent of the elastic moduli values of the constituent materials but rather depends on both the ratio of the elastic moduli and the location across the beam thickness in the E-FGM material function model. This observation was first validated from available kinds of literature and through numerical simulation using ABAQUS and extended to the P-FGM stress analysis. The maximum deflection on the FGM beam occurred for a homogenous steel beam while the minimum deflection was observed on the beam with a P-FGM material function. The results of this work demonstrate that if properly designed and optimized, FGMs can provide an alternative material solution in structural applications.

Material Function of Mycelium-Based Bio-Composite: A Review

Mycelium-based bio-composite materials have been invented and widely applied to different areas, including construction, manufacturing, agriculture, and biomedical. As the vegetative part of a fungus, mycelium has the unique capability to utilize agricultural crop waste (e.g., sugarcane bagasse, rice husks, cotton stalks, straw, and stover) as substrates for the growth of its network, which integrates the wastes from pieces to continuous composites without energy input or generating extra waste. Their low-cost and environmentally friendly features attract interest in their research and commercialization. For example, mycelium-based foam and sandwich composites have been actively developed for construction structures. It can be used as synthetic planar materials (e.g., plastic films and sheets), larger low-density objects (e.g., synthetic foams and plastics), and semi-structural materials (e.g., paneling, flooring, furniture, decking). It is shown that the material function of these composites can be further tuned by controlling the species of fungus, the growing conditions, and the post-growth processing method to meet a specific mechanical requirement in applications (e.g., structural support, acoustic and thermal insulation). Moreover, mycelium can be used to produce chitin and chitosan, which have been applied to clinical trials for wound healing, showing the potential for biomedical applications. Given the strong potential and multiple advantages of such a material, we are interested in studying it in-depth and reviewing the current progress of its related study in this review paper.

How to Teach the Basic Concept of Function in Senior High School: a Lesson Study

Teaching methods are a complex topic in mathematics education. This study aims to analyze the teaching methods of previous relevant studies and design a new lesson study on how to teach the topic of functions at the high school level in China. Lesson study focuses on the basic concepts of function and problem-solving abilities. The researcher uses the research and development method to teach the material function at the high school level. This Lesson Study is used to teach in China. The researcher explains 4 important aspects in designing a lesson study, namely the introduction or opening section, the instructional section or core section, the assessment section, and the closing section.

The “material function” in cinema: Resolving the paradox of the glitch

Glitches pose expressive challenges for digital motion pictures. These problematics reveal a “material function” that determines their identification and prescribes their semantics on-screen. These issues of materiality are familiar from the ideological critiques of avant-garde film in the 1970s, but have not been explored in relation to the semiotics of digital cinema. Developing an understanding of these problematics shows the complex problematics of using glitches for critical and expressive purposes in motion pictures.

Material Effectiveness Model for the Construction of Aluminum Hull

Construction of a hull generally requires several plates and profile material. Early indications for shipbuilding indicate that in manner, the linear function approach for installed material was 75% to 90%, and waste material was 10% to 25%. This study is conducting an assessment of the area of installed material and waste material on small vessels made of aluminum with variations in ship length and the method of approach trend lines both linear and nonlinear. Secondary data retrieval in the form of an aluminum cutting plan for plate material and profile from the AutoCAD application, which is then reprocessed through the FastCAM application to obtain results in the form of identification of installed material and waste material area. Based on variations in ship length and material area results, a scatter plot process was carried out through the Excel application to obtain results in the form of trend line functions with an R-squared determination coefficient of more than 0.9 and the results of the calculation of the intersection between the function of installed material and waste material, and the waste material function with the x-axis uses the balance method. The final result showed that the linear function gives an indication of the effectiveness of the material located in the range of 6 to 23 meters in length of the boat and polynomial function of order 2 in the range of 6 to 18 meters in length, while the waste material area in the two functions maximum 22%.

THE EXACT SOLUTION FOR STRAINS AND STRESSES IN A HOLLOW CYLINDER OF NON-LINEAR VISCOELASTIC MATERIAL SUBJECT TO INTERNAL AND EXTERNAL PRESSURES IN THE CASE OF POWER MATERIAL FUNCTION GOVERNING NON-LINEARITY

We study analytically the exact solution of the quasi-static problem for a thick-walled tube of physically non-linear viscoelastic material obeying the Rabotnov constitutive equation with two arbitrary material functions (a creep compliance and a function which governs physical non-linearity). We suppose that a material is homogeneous, isotropic and incompressible and that a tube is loaded with time-dependent internal and external pressures (varying slowly enough to neglect inertia terms in the equilibrium equations) and that a plain strain state is realized, i.e. zero axial displacements are given on the edge cross sections of the tube. We previously have obtained the closed form expressions for displacement, strain and stress fields via the single unknown function of time and integral operators involving this function, two arbitrary material functions of the constitutive relation, preset pressure values and radii of the tube and derive functional equation to determine this unknown resolving function. Assuming creep complience is arbitrary and choosing the material function governing non-linearity to be power function with a positive exponent, we construct exact solution of the resolving non-linear functional equation, calculate all the convolution integrals involved in the general representation for strain and stress fields and reduce it to simple algebraic formulas convenient for analysis and use. Strains evolution in time is characterized by creep compliance function and loading history. The stresses in this case depend on the current magnitudes of pressures only, they don't depend on creep compliance (i.e. viscoelastic properties of a material) and on loading history. The stress field coincides with classical solution for non-linear elastic material or elastoplastic material with power hardening (for non-decreasing pressure difference). We obtain criteria for increase, decrease or constancy of stresses with respect to radial coordinate in form of inequalities for the exponent value and for difference of pressures. Assuming creep compliance is arbitrary, we study analytically properties of strain and stress fields in a tube under internal pressure growing with constant rate and properties of corresponding stress-strain curves implying measurement of strains at a surface point of a tubular specimen.