Development and Experimental Testing of a FEM Model for the Stress Distribution Analysis in Agricultural Soil due to Artificial Compaction

It is known that the compaction phenomenon of agricultural soil can be defined as an increase in its dry density, respectively as in reduction of its porosity, and it can result from any natural causes as: rainfall impact, soaking, internal water stress from soil, and other. An important role has the artificial compaction, which is generated by the contact with tyres or caterpillars of tractors and agricultural machines. In present, one of the most advanced methods for modelling the phenomenon of stresses propagation in agricultural soil is the Finite Element Method (FEM), which is a numerical method for obtaining approximate solutions of ordinary and partial differential equations of this distribution. In this paper, the soil has been idealised as an elastic-plastic material by Drucker- Prager yield criteria. This paper presents a model for prediction of the stress state in agricultural soil below agricultural tyres in the driving direction and perpendicular to the driving direction, which are different from one another, using the Finite Element Method. General model of analysis was created using FEM, which allows the analysis of equivalent stress distribution and the total displacements distribution in the soil volume, making evident both of the conditions in which the soil compaction is favour and of the study of graphic variation of equivalent stress and the study of shifting in the depth of the soil volume. Using an acquisition data system and pressure sensors, the theoretical model was experimentally checked in the laboratory

Development and Experimental Testing of a FEM Model for the Stress Distribution Analysis in Agricultural Soil due to Artificial Compaction

It is known that the compaction phenomenon of agricultural soil can be defined as an increase in its dry density, respectively as in reduction of its porosity, and it can result from any natural causes as: rainfall impact, soaking, internal water stress from soil, and other. An important role has the artificial compaction, which is generated by the contact with tyres or caterpillars of tractors and agricultural machines. In present, one of the most advanced methods for modelling the phenomenon of stresses propagation in agricultural soil is the Finite Element Method (FEM), which is a numerical method for obtaining approximate solutions of ordinary and partial differential equations of this distribution. In this paper, the soil has been idealised as an elastic-plastic material by Drucker- Prager yield criteria. This paper presents a model for prediction of the stress state in agricultural soil below agricultural tyres in the driving direction and perpendicular to the driving direction, which are different from one another, using the Finite Element Method. General model of analysis was created using FEM, which allows the analysis of equivalent stress distribution and the total displacements distribution in the soil volume, making evident both of the conditions in which the soil compaction is favour and of the study of graphic variation of equivalent stress and the study of shifting in the depth of the soil volume. Using an acquisition data system and pressure sensors, the theoretical model was experimentally checked in the laboratory

PREVENTION MEASURES OF ENVIRONMENTAL RISKS GENERATED BY UNCONTROLLED STORAGE OF WASTES – A REVIEW

The issue regarding the negative impact on the human health and environment, as a result of waste storage by using improper methods remains of great actuality, especially with the increasing trend of the generated wastes quantity. The present paper aims to present the most efficient methods that can be used to reduce and prevent environmental risks caused by uncontrolled storage of agricultural waste. Will be treated theoretical aspects related to the actual state of waste management in the E.U. but also in Romania, methods of treating organic waste, as well as prevention measures of environmental risks

Statistical Analysis of the Tensile Strength of Coal Fly Ash Concrete with Fibers Using Central Composite Design

The influence of coal fly ash and glass fiber waste on the tensile strength of cement concrete was studied using central composite design. Coal fly ash was used to replace 10% of the cement in the concrete mix. Glass fiber was added to improve the tensile properties of the concrete in different dosages and lengths. In total, 14 mixes were investigated, one only with 10% coal fly ash replacement of cement and the other thirteen were determined by the experimental design. Using analysis of variance, the order of importance of the variables was established for each property (flexural strength and split tensile strength). From the nonlinear response surfaces, it was found that higher values of flexural strength were obtained for fibers longer than 12 mm and at a dosage of 1-2%. For split tensile strength, higher values were obtained for fibers with a length of 19–28 mm and at a dosage of 1–1.5%

PREVENTION MEASURES OF ENVIRONMENTAL RISKS GENERATED BY UNCONTROLLED STORAGE OF WASTES – A REVIEW

The issue regarding the negative impact on the human health and environment, as a result of waste storage by using improper methods remains of great actuality, especially with the increasing trend of the generated wastes quantity. The present paper aims to present the most efficient methods that can be used to reduce and prevent environmental risks caused by uncontrolled storage of agricultural waste. Will be treated theoretical aspects related to the actual state of waste management in the E.U. but also in Romania, methods of treating organic waste, as well as prevention measures of environmental risks

Regarding the influence of the particle size of crumb rubber from waste rubber on the physical and mechanical characteristics of reclaimed rubber

Thus, at present, a large amount of rubber waste cannot be higher harnessed due to recovery technologies used. Also, the requirements for new products of rubber worldwide are greater than the production capacity and the availability of raw materials. To offset this balance is necessary to improve technologies for recycling waste rubber so to can get regenerated rubber with the best mechanical physical characteristics. The main technology for obtaining the regenerated rubber is based on the rubber waste shredding and making the powder, so that it can be carried out de-vulcanization in autoclave. All the time it was monitored as the de-vulcanization process to be as economical and less polluting, and this requires that the sizes of the crumb rubber to be optimal. Thus, in the conducted researches was aimed to establish the particle size of crumb rubber from waste rubber so as to obtain an economical de-vulcanization, but also a reclaimed rubber with superior physical and mechanical characteristics. The organization of researches was made so that crumb of rubber waste was divided into 5 groups, bowing from crumb rubber with particle’s size of 1000 μm (RPS1), and reaching up to crumb rubber with particle’s size of 200 μm (RPS 5)

Digital Twin and Smart Manufacturing in Industries: A Bibliometric Analysis with a Focus on Industry 4.0

Technology is being used in our society in all areas, mostly in industry, and generates the most interest in current research since it is a part of day-to-day activities. The main objective of this research was to use bibliometric analysis to analyze the production of scientific literature on digital twin and smart manufacturing with a focus on Industry 4.0, using information from the Web of Science database. To conduct the study, the keywords necessary for data selection were chosen, and then analyzed based on different variables such as author productivity, citations, most productive institutions, publishers with the highest number of publications, scientific document classification, countries with the highest number of publications, and a network analysis using VOSviewer. The results showed Tao F. and Soderberg R. were the main authors, that China was the country with the highest knowledge, and Elsevier was the main publisher. Although the subject has only been in publication for five years, digital twin will constitute an important part of future technologies due to its rapid ascension, proof of this being its yearly productivity (2020 producing the highest number of materials). Papers published in 2021 were excluded, but the difference between the numbers of materials found and those analyzed shows that 2021 will be even more productive than 2020

Investigating the Energy–Economic Growth–Governance Nexus: Evidence from Central and Eastern European Countries

Achieving the goals of sustainable development and poverty reduction implies an important condition for access to electricity for the entire population. In the economic literature, the relationship between electricity consumption and economic growth has different perspectives. The lack of good governance within an economy, besides the deficiencies of energy resources, is a key issue in worsening energy issues for developing countries. These countries have failed to alleviate the energy crises that have hindered development prospects, amid flourishing corruption and inefficient governments. Our research, using a panel methodology, analyzes the long-term relationship between energy consumption, economic growth and good governance for 14 Central and Eastern European countries, over the period 1995–2017. The study demonstrates empirically that there is a causal relationship between electricity consumption and economic growth, underlining the fact that deficiencies in the energy system lead to slowing economic growth. The study also shows that good governance influences electricity and Gross Domestic Product (GDP) consumption, and the governments from Central and Eastern European countries have to restore good governance in the economy, creating an environment conducive to investment in the energy sector, which would increase competition and reduce inefficiencies in the production, transmission, and distribution of energy