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

The eIF4G homolog DAP5/p97 supports the translation of select mRNAs during endoplasmic reticulum stress

DAP5/p97 is a member of the eIF4G family of translation initiation factors that has been suggested to play an important role in the translation of select messenger RNA molecules. We have shown previously that the caspase-cleaved form of DAP5/p97, termed p86, is required for the induction of the endoplasmic reticulum (ER)-stress-responsive internal ribosome entry site (IRES) of the caspase inhibitor HIAP2. We show here that expression of DAP5/p97 is enhanced during ER stress by selective recruitment of DAP5/p97 mRNA into polysomes via the DAP5/p97 IRES. Importantly, enhanced translation mediated by the DAP5/p97 IRES is dependent on DAP5/p97 itself, thus providing a positive feedback loop. In addition, we show that activation of DAP5/p97 and HIAP2 IRES during ER stress requires DAP5/p97. Significantly, the induction of DAP5/p97 during ER stress is caspase-independent, whereas the induction of HIAP2 requires proteolytic processing of DAP5/p97. Thus, DAP5/p97 is a translational activator that selectively modulates translation of specific mRNAs during conditions of cellular stress in both a caspase-dependent and caspase-independent manner

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

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

Ecobiophysical Aspects on Nanosilver Biogenerated from Citrus reticulata

In recent years, a considerable interest was paid to ecological strategies in management of plant diseases and plant growth. Metallic nanoparticles (MNPs) gained considerable interest as alternative to pesticides due to their interesting properties. Green synthesis of MNPs using plant extracts is very advantageous taking into account the fact that plants are easily available and eco-friendly and possess many phytocompounds that help in bioreduction of metal ions. In this research work, we phytosynthesized AgNPs from aqueous extract of Citrus reticulata peels, with high antioxidant, antibacterial, and antifungal potential. These “green” AgNPs were characterized by modern biophysical methods (absorption and FTIR spectroscopy, AFM, and zeta potential measurements). The nanobioimpact of Citrus-based AgNPs on four invasive wetland plants, Cattail (Typha latifolia), Flowering-rush (Butomus umbellatus), Duckweed (Lemna minor), and Water-pepper (Polygonum hydropiper), was studied by absorption spectroscopy, by monitoring the spectral signature of chlorophyll. The invasive plants exhibited different behavior under AgNP stress. Deep insights were obtained from experiments conducted on biomimetic membranes marked with chlorophyll a. Our results pointed out the potential use of Citrus-based AgNPs as alternative in controlling pathogens in aqueous media and in management of aquatic weeds growth

Soil compaction under the wheel of a sprayer

Soil degradation by artificial compaction is recognized by the European Union as a major environmental and agricultural problem. Artificial compaction has worsened with the intensification of mechanized agriculture where heavier machinery is used, often moving on soils with high moisture. Experimental research was designed to determine the influence of five wheel loads and tire inflation pressures, on the contact area, the shape of footprint and the contact pressure, under the wheel of a machine for high accuracy application of phytosanitary treatments in orchards. It was found that the only situation when compaction does not occur is when the tank is empty (2.45 kN wheel load), at lowest tire inflation pressure of 100 kPa. Subsoil compaction (at 0.3-0.4 m) occurs when the sprayer machine’s tank is filled with different amounts of liquid. With empty tank, the sprayer only causes topsoil compaction