1,191 research outputs found
Effect of positional inaccuracies on multielectrode results
This paper investigates the effect of electrode positioning errors on the inverted
pseudosection. Instead of random spacing errors (as usually assumed in geoelectrics)
we exactly measured this effect among field conditions. In the field, in spite of the
greatest possible care, the electrode positions contain some inaccuracy: either in case
of dense undergrowth, or varied topography, or very rocky field. In all these cases, it
is not possible to put the electrodes in their theoretical position. As a consequence,
the position data will contain some error. The inaccuracies were exactly determined
by using a laser distance meter. The geometrical data from real field conditions and
by using Wenner-α, Wenner-β, pole-dipole and pole-pole arrays were then considered
over homogeneous half space.
As we have found, the positioning errors can be regarded as insignificant, even
in case of relatively uncomfortable field conditions. However, in case of very rocky
surface the distortions are more significant, but it is still possible to make some corrections:
either by neglecting a few electrode positions with the greatest positioning
error, or to minimize the inline errors, even on the price that offline deviations are
high
Influence of salicylic acid on phytochelatin synthesis in Zea mays during Cd stress
Abstract: Presoaking maize (Zea mays) seeds in salicylic acid (SA) reduces damage caused by cadmium. In the present work the possible
role of phytochelatins (PCs) in SA-mediated protection against Cd toxicity was investigated. Seeds were presoaked in 0.5 mM SA, and
seedlings were grown in hydroponic solution containing 0, 0.01, 0.015, or 0.025 mM Cd. Treatment with Cd increased the PC levels in
maize roots, but only slight changes were observed in the leaves. Long-term exposure to Cd decreased the phytochelatin synthase (PCS)
activity in the roots and led to an increase in PCS and glutathione reductase (GR) activities in maize leaves. Although presoaking seeds
in SA solution before exposure to Cd may reduce the level of heavy metal injury and has an effect on the composition of individual PCs,
this protection is not directly connected with the altered regulation of PCs
Agroforestry research and development in Hungary
PosterHungary is a traditionally agricultural country, therefore the „old” agroforestry technologies (windbreaks, shelter-belts, hedgerows, wooded pastures) had been applied in large scale in the past centuries. From the early nineties the positive trend of increasing area of protective forest belts first stopped, then reversed. The former area of forest belts (35 000 hectares) has decreased by 50% up to this time. The high ratio of “risky” territories demonstrates the strong need for the development of rural areas, by eg. the implementation of innovative agricultural technology able to increase social-economic sustainability.
Followed from the forest belt research project started in the ’60s and ran over the course of several decades, a new line of experiments has started some years ago in the UWH Faculty of Forestry with the aim to develop a modell for the design and construction of forest belts by the combination of digital modelling and field sampling with analytical methods. The examination and development of windbreaks and shelter belt system will be continued within the frame of a national project focused on climate – vegetation relationship.
In 2012 the UWH Cooperational Research Centre, together with local cooperatives and farmers have set the objective of integrating modern agroforestry technologies in their on-farm agricultural activity and establishing new experimental sites available for future research and demonstration purposes. This cooperation will also contribute to the „AGFORWARD” international research project on agroforestry.
In the Corvinus University of Budapest, Department of Ecological Farming and Sustainable Production Systems an R&D project on forest gardens started in 2010.
From this year agroforestry appears among the “determinative research and development subjects” of the Ministry of Rural Development. This development and the increasing number of research projects show agroforestry rising again in Hungary
Magnetization and susceptibility of ferrofluids
A second-order Taylor series expansion of the free energy functional provides
analytical expressions for the magnetic field dependence of the free energy and
of the magnetization of ferrofluids, here modelled by dipolar Yukawa
interaction potentials. The corresponding hard core dipolar Yukawa reference
fluid is studied within the framework of the mean spherical approximation. Our
findings for the magnetic and phase equilibrium properties are in quantitative
agreement with previously published and new Monte Carlo simulation data.Comment: 8 pages including 4 figure
Discovery of the spectroscopic binary nature of three bright southern Cepheids
We present an analysis of spectroscopic radial velocity and photometric data
of three bright Galactic Cepheids: LR Trianguli Australis (LR TrA), RZ Velorum
(RZ Vel), and BG Velorum (BG Vel). Based on new radial velocity data, these
Cepheids have been found to be members of spectroscopic binary systems.
The ratio of the peak-to-peak radial velocity amplitude to photometric
amplitude indicates the presence of a companion for LR TrA and BG Vel. IUE
spectra indicate that the companions of RZ Vel and BG Vel cannot be hot stars.
The analysis of all available photometric data revealed that the pulsation
period of RZ Vel and BG Vel varies monotonically, due to stellar evolution.
Moreover, the longest period Cepheid in this sample, RZ Vel, shows period
fluctuations superimposed on the monotonic period increase. The light-time
effect interpretation of the observed pattern needs long-term photometric
monitoring of this Cepheid. The pulsation period of LR TrA has remained
constant since the discovery of its brightness variation.
Using statistical data, it is also shown that a large number of spectroscopic
binaries still remain to be discovered among bright classical Cepheids.Comment: 9 pages, 14 figure
InSight Aerothermal Environment Assessment
The Mars Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft, which successfully touched down on the planet surface on November 26, 2018, was proposed as a near build-to-print copy of the Mars Phoenix vehicle to reduce the overall cost and risk of the mission. Since the lander payload and the atmospheric entry trajectory were similar enough to those of the Phoenix mission, it was expected that the Phoenix thermal protection material thickness would be sufficient to withstand the entry heat load. However, allowances were made for increasing the heatshield thickness because the planned spacecraft arrival date coincided with the Mars dust storm season. The aftbody Thermal Protection System (TPS) components were not expected to change. In a first for a US Mars mission, the aerothermal environments for InSight included estimates of radiative heat flux to the aftbody from the wake. The combined convective and radiative heat fluxes were used to determine if the as-flown Phoenix thermal protection system (TPS) design would be sufficient for InSight. Although the radiative heat fluxes on the aftbody were predicted to be comparable to, or even higher than the local convective heat fluxes, all analyses of the aftbody TPS showed that the design would still be adequate. Aerothermal environments were computed for the vehicle from post-flight reconstruction of the atmosphere and trajectory and compared with the design environments. These comparisons showed that the predicted as-flown conditions were less severe than the design conditions
Type Iax SNe as a few-parameter family
We present direct spectroscopic modeling of five Type Iax supernovae (SNe)
with the one dimensional Monte Carlo radiative transfer code TARDIS. The
abundance tomography technique is used to map the chemical structure and
physical properties of the SN atmosphere. Through via fitting of multiple
spectral epochs with self-consistent ejecta models, we can then constrain the
location of some elements within the ejecta. The synthetic spectra of the
best-fit models are able to reproduce the flux continuum and the main
absorption features in the whole sample. We find that the mass fractions of
IGEs and IMEs show a decreasing trend toward the outer regions of the
atmospheres using density profiles similar to those of deflagration models in
the literature. Oxygen is the only element, which could be dominant at higher
velocities. The stratified abundance structure contradicts the well-mixed
chemical profiles predicted by pure deflagration models. Based on the derived
densities and abundances, a template model atmosphere is created for the SN Iax
class and compared to the observed spectra. Free parameters are the scaling of
the density profile, the velocity shift of the abundance template, and the peak
luminosity. The results of this test support the idea that all SNe Iax can be
described by a similar internal structure, which argues for a common origin of
this class of explosions.Comment: 21 pages, 7 tables, 16 figures, accepted by MNRA
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