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In agrotechnical practice, it was found that between qualitative indices, which express the sowing precision achieved by precision planters determined in the laboratory, and those determined under operating conditions, that there are certain differences, which are sometimes quite significant. The decrease in the value of the quality indices was manifested by the increase of the number of mistakes, either of the number of double planting holes (with at least two seeds), or of the number of missing planting holes. Both cases are unfavorable for the agricultural producer, generating production losses. This paper discusses the influence of the degree of soil grinding on sowing precision in operating conditions, by determining the spectrum of the vibrations induced in the mechanical structure of row units of a precision planter in contact with the soil of three different plots for three working speeds: 4, 6, and 8 km·h−1. Later, the vibrations were simulated under laboratory conditions, on the stand, by means of rubber hemispheres (with diameters between 30 and 100 mm, corresponding to soil fractions resulting from the determination of the degree of soil grinding) mounted on rubber bands, which actuated the seed meters, for testing under an accelerated regime, outside of the optimal agricultural periods (out of season: beginning mid-May until the end of March), in order to obtain the accuracy of the precision planters. It was found that the sowing precision determined in stationary conditions on the stand, and on a plot with an appropriate degree of seedbed preparation, decreased between 2.92% (at 4 km·h−1) and 6.67% (at 8 km·h−1). The main objective of the tests was to reduce labor costs, which was necessary for the staff involved for determining the qualitative indices of work in real field operating conditions, eliminating fuel consumption, while reducing the duration of testing dependent on meteorological factors (season, temperatures, and precipitation, etc.).
Dan Cujbescu; Iuliana Găgeanu; Cătălin Persu; Mihai Matache; Valentin Vlăduț; Iulian Voicea; Gigel Paraschiv; Sorin Biriș; Nicoleta Ungureanu; Gheorghe Voicu; George Ipate. Simulation of Sowing Precision in Laboratory Conditions. Applied Sciences 2021, 11, 6264 .
AMA StyleDan Cujbescu, Iuliana Găgeanu, Cătălin Persu, Mihai Matache, Valentin Vlăduț, Iulian Voicea, Gigel Paraschiv, Sorin Biriș, Nicoleta Ungureanu, Gheorghe Voicu, George Ipate. Simulation of Sowing Precision in Laboratory Conditions. Applied Sciences. 2021; 11 (14):6264.
Chicago/Turabian StyleDan Cujbescu; Iuliana Găgeanu; Cătălin Persu; Mihai Matache; Valentin Vlăduț; Iulian Voicea; Gigel Paraschiv; Sorin Biriș; Nicoleta Ungureanu; Gheorghe Voicu; George Ipate. 2021. "Simulation of Sowing Precision in Laboratory Conditions." Applied Sciences 11, no. 14: 6264.
Our paper presents the hammer mill working process optimization problem destined for milling energetic biomass (MiscanthusGiganteus and Salix Viminalis). For the study, functional and constructive parameters of the hammer mill were taken into consideration in order to reduce the specific energy consumption. The energy consumption dependency on the mill rotor spinning frequency and on the sieve orifices in use, as well as on the material feeding flow, in correlation with the vegetal biomass milling degree was the focus of the analysis. For obtaining this the hammer mill was successively equipped with 4 different types of hammers that grind the energetic biomass, which had a certain humidity content and an initial degree of reduction ratio of the material. In order to start the optimization process of hammer mill working process, 12 parameters were defined. The objective functions which minimize hammer mill energy consumption and maximize the milled material percentage with a certain specific granulation were established. The results obtained can serve as the basis for choosing the optimal working, constructive, and functional parameters of hammer mills in this field, and for a better design of future hammer mills.
Gigel Paraschiv; Georgiana Moiceanu; Gheorghe Voicu; Mihai Chitoiu; Petru Cardei; Mirela Dinca; Paula Tudor. Optimization Issues of a Hammer Mill Working Process Using Statistical Modelling. Sustainability 2021, 13, 973 .
AMA StyleGigel Paraschiv, Georgiana Moiceanu, Gheorghe Voicu, Mihai Chitoiu, Petru Cardei, Mirela Dinca, Paula Tudor. Optimization Issues of a Hammer Mill Working Process Using Statistical Modelling. Sustainability. 2021; 13 (2):973.
Chicago/Turabian StyleGigel Paraschiv; Georgiana Moiceanu; Gheorghe Voicu; Mihai Chitoiu; Petru Cardei; Mirela Dinca; Paula Tudor. 2021. "Optimization Issues of a Hammer Mill Working Process Using Statistical Modelling." Sustainability 13, no. 2: 973.
The pretreatment of lignocellulosic biomass (LC biomass) prior to the anaerobic digestion (AD) process is a mandatory step to improve feedstock biodegradability and biogas production. An important potential is provided by lignocellulosic materials since lignocellulose represents a major source for biogas production, thus contributing to the environmental sustainability. The main limitation of LC biomass for use is its resistant structure. Lately, biological pretreatment (BP) gained popularity because they are eco-friendly methods that do not require chemical or energy input. A large number of bacteria and fungi possess great ability to convert high molecular weight compounds from the substrate into lower mass compounds due to the synthesis of microbial extracellular enzymes. Microbial strains isolated from various sources are used singly or in combination to break down the recalcitrant polymeric structures and thus increase biogasgeneration. Enzymatic treatment of LC biomass depends mainly on enzymes like hemicellulases and cellulases generated by microorganisms. The articles main purpose is to provide an overview regarding the enzymatic/biological pretreatment as one of the most potent techniques for enhancing biogas production.
Mariana Ferdeș; Mirela Dincă; Georgiana Moiceanu; Bianca Zăbavă; Gigel Paraschiv. Microorganisms and Enzymes Used in the Biological Pretreatment of the Substrate to Enhance Biogas Production: A Review. Sustainability 2020, 12, 7205 .
AMA StyleMariana Ferdeș, Mirela Dincă, Georgiana Moiceanu, Bianca Zăbavă, Gigel Paraschiv. Microorganisms and Enzymes Used in the Biological Pretreatment of the Substrate to Enhance Biogas Production: A Review. Sustainability. 2020; 12 (17):7205.
Chicago/Turabian StyleMariana Ferdeș; Mirela Dincă; Georgiana Moiceanu; Bianca Zăbavă; Gigel Paraschiv. 2020. "Microorganisms and Enzymes Used in the Biological Pretreatment of the Substrate to Enhance Biogas Production: A Review." Sustainability 12, no. 17: 7205.
In order to obtain bioenergy (biogas, biofuel) or pellets, different types of lignocellulosic biomass are subjected to a mechanical pretreatment, first by size reduction, then by separating, and ultimately by fracturing or bio-refining. Biomass processing mainly refers to a grinding process that occurs until reaching certain limits. The size reduction process, such as grinding, is an operation that is executed with different levels of energy consumption, considering biomass mechanical characteristics and the necessary grinding level. This paper, illustrates a comparative analysis of experimental results obtained by grinding multiple types of vegetal biomass (Miscanthus, corn stalks, alfalfa, willow) used in the process of bio-refining and bio-fracturing. Experiments were realized using both a laboratory knife mill Grindomix GM200 (Retsch GmbH, Haan, Germany), and a 22 kW articulated hammer mill, using different grinding system speeds and different hammer mill sieves. Results have shown that biomass mechanical pre-processing grinding leads to supplementary costs in the overall process through bio-refining or bio-fracturing in order to obtain bio-products or bio-energy. So, specific energy consumption for grinding using a hammer mill can reach 50–65 kJ/kg for harvested Miscanthus biomass, and 35–50 kJ/kg for dried energetic willow, using a 10 mm orifice sieve, values which increase processing costs.
Georgiana Moiceanu; Gigel Paraschiv; Gheorghe Voicu; Mirela Dinca; Olivia Negoita; Mihai Chitoiu; Paula Tudor. Energy Consumption at Size Reduction of Lignocellulose Biomass for Bioenergy. Sustainability 2019, 11, 2477 .
AMA StyleGeorgiana Moiceanu, Gigel Paraschiv, Gheorghe Voicu, Mirela Dinca, Olivia Negoita, Mihai Chitoiu, Paula Tudor. Energy Consumption at Size Reduction of Lignocellulose Biomass for Bioenergy. Sustainability. 2019; 11 (9):2477.
Chicago/Turabian StyleGeorgiana Moiceanu; Gigel Paraschiv; Gheorghe Voicu; Mirela Dinca; Olivia Negoita; Mihai Chitoiu; Paula Tudor. 2019. "Energy Consumption at Size Reduction of Lignocellulose Biomass for Bioenergy." Sustainability 11, no. 9: 2477.