Ampelographic characterization - preliminary results of the nine most appreciated autochthonous Vitis vinifera L. varieties from Romania

The paper presents an up-to-date description of some autochthonous, old and valuable grapevine varieties maintained within the germplasm collection belonging to the University of Agronomical Science and Veterinary Medicine Bucharest, respectively 3 varieties for red wines ('Fetească neagră', 'Băbească neagră', ‚Busuioacă de Bohotin') and 6 varieties for white wines ('Fetească albă', 'Fetească regală', 'Galbenă de Odobeşti', 'Grasă de Cotnari', 'Tămâioasă românească' and 'Zghihară de Huşi').  The results obtained by applying standardized methodology for grape quantitative and qualitative parameters for three consecutive years, reveal the main characteristics for each variety and also the specific genotype response to particular pedoclimatic conditions.  In comparison to 'Cabernet Sauvignon' as reference cultivar, 'Băbească neagră' and 'Busuioacă de Bohotin' varieties were characterized by higher values for the sizes and weights of the berries, and 'Fetească neagră' by heavier bunches and higher sugar juice content.  The white grape varieties in comparison to 'Chardonnay' as reference cultivar, were remarked either by bigger bunches with high to very high sugar content ('Fetească regală', 'Grasă de Cotnari', 'Tămâioasă românească'), or by constancy of bunch weight and titratable acidity of must ('Fetească albă', 'Galbenă de Odobeşti' and 'Zghihară de Huşi')

Rootstocks and wild grapevines responses to salinity

A study of the effects induced by salt solutions applied on in vitro cultures and potted vines comparing five widely used rootstocks in Romania and six wild accessions from five populations of Vitis vinifera L. ssp. sylvestris (Gmelin) Hegi was performed. For in vitro test, all genotypes were analyzed for toxicity symptoms appearance in media containing 17, 32 and 49 mM NaCl. The same accessions, as potted plants, were subjected to salt treatments with 51, 68 and 102 mM NaCl, and were evaluated in terms of growth reduction and toxicity symptoms emergence after one month of salt treatment. P, K and Na contents were detected in in vitro plantlets and potted plants. Results showed significant differences among genotypes and between the in vitro and potted treatments. The wild grapevine individuals, in comparison to the rootstocks, expressed a higher ability to adapt to the salt stress in both type of treatments. In comparison with the rootstocks, the wild grapevine individuals were characterized by a higher content of P and lower contents of K and Na, which could be directly correlated with their ability to uptake and accumulate a higher level of Na and Cl into their tissues

Role of transport performance on neuron cell morphology

The compartmental model is a basic tool for studying signal propagation in neurons, and, if the model parameters are adequately defined, it can also be of help in the study of electrical or fluid transport. Here we show that the input resistance, in different networks which simulate the passive properties of neurons, is the result of an interplay between the relevant conductances, morphology and size. These results suggest that neurons must grow in such a way that facilitates the current flow. We propose that power consumption is an important factor by which neurons attain their final morphological appearance.Comment: 9 pages with 3 figures, submitted to Neuroscience Letter

Some constructions of almost para-hyperhermitian structures on manifolds and tangent bundles

In this paper we give some examples of almost para-hyperhermitian structures on the tangent bundle of an almost product manifold, on the product manifold $M\times\mathbb{R}$, where $M$ is a manifold endowed with a mixed 3-structure and on the circle bundle over a manifold with a mixed 3-structure.Comment: 10 pages; This paper has been presented in the "4th German-Romanian Seminar on Geometry" Dortmund, Germany, 15-18 July 200

Effect of substrate thermal resistance on space-domain microchannel

In recent years, Fluorescent Melting Curve Analysis (FMCA) has become an almost ubiquitous feature of commercial quantitative PCR (qPCR) thermal cyclers. Here a micro-fluidic device is presented capable of performing FMCA within a microchannel. The device consists of modular thermally conductive blocks which can sandwich a microfluidic substrate. Opposing ends of the blocks are held at differing temperatures and a linear thermal gradient is generated along the microfluidic channel. Fluorescent measurements taken from a sample as it passes along the micro-fluidic channel permits fluorescent melting curves to be generated. In this study we measure DNA melting temperature from two plasmid fragments. The effects of flow velocity and ramp-rate are investigated, and measured melting curves are compared to those acquired from a commercially available PCR thermocycler

Analysis of low Reynolds number flow around a heated circular cylinder

The objective of this study is to investigate the forced convection from and the flow around a heated cylinder. Experimental and computational results are presented for laminar flow around a heated circular cylinder with a diameter of 10 mm. The experiments were carried out using Particle Image Velocimetry (PIV) in a wind tunnel, and numerical simulations using an in-house code and a commercial software package, FLUENT. This paper pre-sents comparisons for vorticity and temperature contours in the wake of the cylinder. Experimental and computa-tional results are compared with those available in the literature for heated and unheated cylinders. An equation is suggested for a temperature-dependent coefficient defining a reference temperature to be used in place of the con-stant used in other studies. An attempt is also made to correct differences between average cylinder surface tem-perature and measured interior temperature of the cylinder

Optimal Counter-current exchange networks

We present a general analysis of exchange devices linking their efficiency to the geometry of the exchange surface and supply network. For certain parameter ranges, we show that the optimal exchanger consists of densely packed pipes which can span a thin sheet of large area (an “active layer”), which may be crumpled into a fractal surface and supplied with a fractal network of pipes. We derive the efficiencies of such exchangers, showing the potential for significant gains compared to regular exchangers (where the active layer is flat), using parameters relevant to biological systems

Performance of discrete heat engines and heat pumps in finite time

The performance in finite time of a discrete heat engine with internal friction is analyzed. The working fluid of the engine is composed of an ensemble of noninteracting two level systems. External work is applied by changing the external field and thus the internal energy levels. The friction induces a minimal cycle time. The power output of the engine is optimized with respect to time allocation between the contact time with the hot and cold baths as well as the adiabats. The engine's performance is also optimized with respect to the external fields. By reversing the cycle of operation a heat pump is constructed. The performance of the engine as a heat pump is also optimized. By varying the time allocation between the adiabats and the contact time with the reservoir a universal behavior can be identified. The optimal performance of the engine when the cold bath is approaching absolute zero is studied. It is found that the optimal cooling rate converges linearly to zero when the temperature approaches absolute zero.Comment: 45 pages LaTeX, 25 eps figure

A linear nonequilibrium thermodynamics approach to optimization of thermoelectric devices

Improvement of thermoelectric systems in terms of performance and range of applications relies on progress in materials science and optimization of device operation. In this chapter, we focuse on optimization by taking into account the interaction of the system with its environment. For this purpose, we consider the illustrative case of a thermoelectric generator coupled to two temperature baths via heat exchangers characterized by a thermal resistance, and we analyze its working conditions. Our main message is that both electrical and thermal impedance matching conditions must be met for optimal device performance. Our analysis is fundamentally based on linear nonequilibrium thermodynamics using the force-flux formalism. An outlook on mesoscopic systems is also given.Comment: Chapter 14 in "Thermoelectric Nanomaterials", Editors Kunihito Koumoto and Takao Mori, Springer Series in Materials Science Volume 182 (2013