Search results for "Allium"

Considerazioni citotassonomiche e corologiche su Allium chamaespathum Boiss. (Alliaceae) geofita nuova per la flora italiana.

2010

Oggetto di questo studio è una singolare popolazione di Allium a fioritura autunnale, rinvenuta presso Reggio Calabria (Italia meridionale), la quale, per alcune caratteristiche vegetative e fiorali, rientra chiaramente nella sezione Allium. Le piante sono caratterizzate da un habitus robusto, foglie subcilindriche ampiamente fistolose, spata unica, caduca, slargata, con appendice fistolosa, lacerantesi lateralmente, infiorescenza globosa, densa, perianzio cilindrico con tepali conniventi, stami con filamenti laminari, dimorfi, gli esterni semplici e gli interni tricuspidati, e ovario con nettari ben sviluppati. Oltre alla fioritura tardiva (IX-X), gli individui di questa popolazione, prese…

Effetti della concimazione sulla qualità dell'aglio coltivato in Sicilia

2009

Effetti della concimazione sulla qualità dell'aglio coltivato in Sicilia. Effects of fertilization on the quality of garlic grown in Sicily.

2010

In order to expand this crop and to improve bulbs quality a study was carried out to evaluate different fertilization techniques. Four fertilization formulas were evaluated: 1) mineral fertilization commonly used by Paceco producers - pre-planting with 55, 110 and 80 kg ha-1 of N, P2O5 and K2O - post planting with 47 and 46 kg ha-1 of N and K2O; 2) organic fertilization with an organic mix - pre-planting with 320 and 240 kg ha-1 of N and P2O5; 3) mineral fertilization - pre-planting with 40, 70 and 100 kg ha-1 of N, P2O5 and K2O - post-planting with 80 kg ha-1 of N half at 3-4 leaves and half at bulbs formation; 4) only post-planting fertilization with 52 and 184 kg ha-1 of N and K2O, half …

Effetti della densità d'impianto e della concimazione azotata sulla qualità dell'aglio coltivato in Sicilia

2010

Phylogeny of the autumn-flowering species of A. sect. Codonoprasum from the Mediterranean region.

2009

Il genere Allium (Alliaceae) in Sicilia

2008

A procedure to evaluate the seven parameters of the two-diode model for photovoltaic modules

2019

Abstract The paper presents an analytical procedure to calculate the seven parameters of the two-diode model of photovoltaic (PV) panels for any value of the solar irradiance and cell temperature. Six parameters (the photocurrent, the diode reverse saturation currents, the quality factor of the first diode and the series and shunt resistances), are evaluated by solving the equations related to the properties of the main points of the current-voltage (I-V) characteristics. The further information, necessary to calculate the entire set of seven truly independent parameters, is based on two conditions that have to be simultaneously satisfied: 1) the exclusion of negative values of the model pa…

An accurate one-diode model suited to represent the current-voltage characteristics of crystalline and thin-film photovoltaic modules

2020

Abstract In this paper a new one-diode model, conceived in order to be used to represent the current-voltage curves of both crystalline and thin-film photovoltaic modules, is presented. The model parameters are calculated from the information contained in the datasheets issued by manufactures by means of simple iterative procedures that do not require the assumption of simplifying hypotheses. Some innovative relations describing the dependence of the parameters from the solar irradiance and cell temperature are adopted in order to permit the model to reliably simulate the electrical behaviour of photovoltaic devices operating in real conditions. The ability of the model to calculate the cur…

Low vacuum photo electron emitting thin films

2009

Impact ionisation is a standard procedure to ionise gaseous or vaporisable substances in organic mass spectrometry. In this work, a "softer" ionisation is introduced which seems to be an alternative ion source for reducing collision between substance molecules and the hot internal walls of the box. Through collision mainly found in impact ionisation sources, fragments are built especially from thermally sensitive substances falsifying the spectra. We present here photoelectron emitting materials for the soft ionisation using semiconducting compounds, galliumn nitride (GaN), and a representative of the borides, lanthanum hexaboride (LaB 6 ). They are evaluated by photoelectron spectroscopic …

Structure and properties of GaNxOy films grown by nitridation of GaAs (100) substrates

2004

GaAs (100) substrates have been heat-treated in a metal-organic chemical vapor deposition reactor under flows of NH 3 and an oxygen organo-metallic precursor at temperatures between 650°C and 750°C. Yellowish films formed at the surface of all the samples. Gallium, nitrogen and oxygen were detected by EDX analysis of the films. The oxygen content was estimated in the range of at 5-10 at% depending on the heat-treatment temperature. X-ray diffraction and HRTEM results indicate that the structure of the films corresponds to the hexagonal wurtzite phase of GaN with an expanded unit cell. Raman spectra show hands corresponding to the Raman active GaN modes as well as disorder-activated broad ba…