Facultad Regional Venado Tuerto
http://hdl.handle.net/20.500.12272/116
2024-03-29T05:20:44ZImprovement of growth and yield of soybean plants through the application of non-thermal plasmas to seeds with different health status.
http://hdl.handle.net/20.500.12272/9997
Improvement of growth and yield of soybean plants through the application of non-thermal plasmas to seeds with different health status.
Soybean (Glycine max (L.) Merrill) is a globally important crop, providing oil and
protein. Diaporthe/Phomopsis complex includes seed-borne pathogens that affect
this legume. Non-thermal plasma treatment is a fast, cost-effective and
environmental-friendly technology. Soybean seeds were exposed to a quasi stationary (50 Hz) dielectric barrier discharge plasma operating at atmospheric
pressure air. Different carrying gases (O2 and N2) and barrier insulating materials
were used. This work was performed to test if the effects of non-thermal plasma
treatment applied to healthy and infected seeds persist throughout the entire cycle
of plants. To this aim, lipid peroxidation, activity of catalase, superoxide
dismutase and guaiacol peroxidase, vegetative growth and agronomic traits were
analysed. The results here reported showed that plants grown from infected seedsdid not trigger oxidative stress due to the reduction of pathogen incidence in seeds
treated with cold plasma. Vegetative growth revealed a similar pattern for plants
grown from treated seeds than that found for the healthy control. Infected
control, by contrast, showed clear signs of damage. Moreover, plasma treatment
itself increased plant growth, promoted a normal and healthy physiological
performance and incremented the yield of plants. The implementation of this
technology for seeds treatment before sowing could help reducing the use of
agrochemicals during the crop cycle.
2019-01-01T00:00:00ZPlasma Cutting of Concrete: Heat Propagation and Molten Material Removal From the Kerf.
http://hdl.handle.net/20.500.12272/9981
Plasma Cutting of Concrete: Heat Propagation and Molten Material Removal From the Kerf.
An experimental investigation of heat propagation
in the case of plasma cutting of concrete is reported. The
experiments were carried out by using a high-enthalpy nitrogen
plasma jet generated in a dc vortex-stabilized nontransferred
arc torch. Concrete plates of different thicknesses up to 52 mm
and with and without steel reinforcement were used. The plates
were placed horizontally while cutting. The heat conduction losses
inside the material were estimated by comparing thermocouple
measurements and theoretical temperatures obtained with an
analytical model of the heat propagation in the material. The
influence of the molten concrete layer that separates the plasma to
the solid material due to the high viscosity of the liquid concrete
was accounted for. The power losses below the material in the
extinguishing plasma have also been determined from calorimet ric measurements. For different plate thicknesses and cutting
velocities, a complete power balance of the process is performed
with the calculation of the cutting efficiency on the basis of
various relevant power terms. In addition, the hydrodynamics
of the molten concrete layer in the kerf is analyzed. For a mean
power level of 11.2 kW and a nitrogen gas flow rate of 25 Nl/min,
the torch is able to cut a concrete plate of 52 mm in thickness
with a speed of 20 mm/min and a whole efficiency of about 30%.
The viscosity force is the main limiting factor on the cutting
velocity in thick plates.
2019-01-01T00:00:00ZGlow Discharge in a High-Velocity Air Flow: The Role of the Associative Ionization Reactions Involving Excited Atoms.
http://hdl.handle.net/20.500.12272/9978
Glow Discharge in a High-Velocity Air Flow: The Role of the Associative Ionization Reactions Involving Excited Atoms.
A kinetic scheme for non-equilibrium regimes of atmospheric pressure air discharges
is developed. A distinctive feature of this model is that it includes associative ionization with
the participation of N(2D, 2P) atoms. The thermal dissociation of vibrationally excited nitrogen
molecules and the electronic excitation from all the vibrational levels of the nitrogen molecules are
also accounted for. The model is used to simulate the parameters of a glow discharge ignited in
a fast longitudinal flow of preheated (T0 = 1800–2900 K) air. The results adequately describe the
dependence of the electric field in the glow discharge on the initial gas temperature. For T0 = 1800 K,
a substantial acceleration in the ionization kinetics of the discharge is found at current densities larger
than 3 A/cm2
, mainly due to the N(2P) + O(3P) → NO+ + e process; being the N(2P) atoms produced
via quenching of N2(A3P
u
+) molecules by N(4S) atoms. Correspondingly, the reduced electric field
noticeably falls because the electron energy (6.2 eV) required for the excitation of the N2(A3P
u
+) state
is considerably lower than the ionization energy (9.27 eV) of the NO molecules. For higher values
of T0, the associative ionization N(2D) + O(3P) → NO+ + e process (with a low–activation barrier
of 0.38 eV) becomes also important in the production of charged particles. The N(2D) atoms being
mainly produced via quenching of N2(A3P
u
+) molecules by O(3P) atoms.
2019-01-01T00:00:00ZDeterminación de la resistencia al aplastamiento en madera de Pinus Elliotti y de Eucalyptus Grandis.
http://hdl.handle.net/20.500.12272/9974
Determinación de la resistencia al aplastamiento en madera de Pinus Elliotti y de Eucalyptus Grandis.
En el cálculo de estructuras de madera, la capacidad portante de las uniones, resulta
de vital importancia para garantizar la seguridad estructural del conjunto. El parámetro
imprescindible para su determinación es el valor de la resistencia al aplastamiento de
la madera utilizada. El INTI-CIRSOC 601 especifica valores en función de la gravedad
anhidra de la madera y del diámetro del elemento de unión. Valores que por provenir
de las NDS 2005 deben ser verificados para maderas de uso estructural en Argentina.
En este trabajo se ha determinado la resistencia al aplastamiento para madera de
Pinus elliottii y de Eucalyptus grandis procedentes de bosques implantados. Se
realizaron 224 ensayos de acuerdo a la norma UNE-EN 383:2007, utilizando perno
rígido de diámetro 7 mm, 118 en la dirección paralela a la fibra y 106 en la dirección
perpendicular. La resistencia característica al aplastamiento percentil 5 %, para la
dirección paralela y perpendicular, respectivamente, fueron: de 15,6 N/mm2 y de 11,3
N/mm2 para el Pinus elliottii, y de 24,6 N/mm2 y de 14,4 N/mm2 para el Eucalyptus
grandis. En línea con estudios anteriores, los valores obtenidos son inferiores a los
propuestos en el Reglamento Argentino, variando entre un 60% y un 73%. Se está
avanzando en ampliar la base de ensayos a más especies y procedencias a fin de
proponer nuevos valores para el CIRSOC 601 o validar los existentes.
In the calculation of wooden structures, the bearing capacity of the joints is of vital
importance to guarantee the structural safety of the whole. The essential parameter for
its determination is the value of the embedment strength of the wood used. The
Regulation CIRSOC 601 specifies crushing resistance values based on the anhydrous
gravity of the wood and the diameter of the bolt. These values must be verified for
wood for structural use in Argentina. In this work, the values of the embedment strength
were determined for wood of Pinus elliottii and Eucalyptus grandis coming from
implanted forests.224 tests were performed in accordance with UNE-EN 383 using a
rigid bolt with a diameter of 7 mm, 118 in the direction parallel to the grain and 106 in
the perpendicular direction. The results obtained for characteristic embedment
strength percentile 5%, for the parallel and perpendicular direction, respectively, were:
15.6 N/mm2 and 11.3 N/mm2
for Pinus elliottii, and 24.6 N/mm2 and of 14.4 N/mm2
for Eucalyptus grandis. In line with previous studies, the values obtained are lower than
those proposed in CIRSOC 601, for these species and bolt diameter, varying between
60% and 73%. Progress is being made to expand the testing base to more species
and provenances in order to propose new values for CIRSOC 601 or validate existing
ones.
2022-01-01T00:00:00Z