Search results for "Conductor"
showing 10 items of 1270 documents
Photocatalytic membrane reactors: fundamentals, membrane materials and operational issues
2013
Abstract: This chapter reports the properties of semiconductor materials used in heterogeneous photocatalysis together with a comparison of heterogeneous photocatalytic systems and a brief description of the types of membranes that can be used. Some aspects of membrane operations, such as fouling, separation of a photocatalyst and effectiveness of photodegradation on permeate quality are discussed.
Electrical characterization of low power CIGSSe photovoltaic modules
2015
This paper presents the electrical characterization of low power CIGSSe photovoltaic (PV) modules. Such investigation is achieved to perform a comparison of their performances with conventional silicon PV modules. For this purpose, a test bench, suitable for the characterization of both traditional and innovative low power modules, has been set-up and experimental results are accurately described and discussed.
Methodologies to uprate an overhead line. Italian TSO case study
2013
The amount of wind power and other time-variable non-dispatchable electricity generation is rapidly increasing across the world, causing a significant change in the electrical system configuration. The existing structural asset isn't adequate to dispatch these new power that have a priority in the energy dispatching. In addiction the outage of substations on the grid and the increase of consumptions have caused growing load currents. In order to satisfy these needs, TSOs have adopted new measures on existing power lines and N-1 criteria to ensures the electrical grid security. These particular devices are Dynamic Thermal Rating (DTR) systems. After introducing thermal resistant conductors a…
Dynamic thermal rating for overhead lines: Self-adaptive protection device
2013
The increase in the consumption of electricity, the stringent environmental restrictions and the need to keep costs, make ever more meaningful the need for a flexible operation of existing overhead lines. This paper studies the possibility to use a dynamic thermal rating for overhead line starting from the analysis of the mathematical model and the ability of the latter to reflect the temperature of an overhead conductor in different ambient condition; then it simulates the thermal behaviour of a conductor both in steady state and dynamic one. Finally the paper shows a method for a self-adaptive thermal protection system.
Uprating an overhead line. Italian TSO applications to increase system N-1 security
2013
This paper analyzes innovative devices to optimize the energy flows transmission on existing overhead lines. Indeed sometimes the structural asset isn’t adequate to manage energy generated by Renewable Energy Source (RES) in particular operating conditions. In addiction the outage of primary substations on the grid and the increase of consumptions have caused growing load currents. In order to satisfy these needs, TSOs have adopted new measures on existing power lines and N-1 criteria to ensures the electrical grid security. These particular devices are Dynamic Rating systems. After introducing thermal resistant conductors and Dynamic Rating (DR) solutions, paper reports two different appli…
Investigation on Cascode Devices for High Frequency Electrical Drives Applications
2019
In the last years a widespread development in the market of electrical drives employing high-speed electrical machines has occurred in various industrial fields, due to the extremely high power density that can be reached. Nevertheless, to maintain output power quality without using bulky filtering networks, DC-AC converters should be controlled by means of higher PWM switching frequencies. New switching device technologies, such as Field Effect Transistors based on SiC and GaN, are therefore gathering momentum in order to comply with the higher working frequencies. To operate under high frequencies and at the same time at high voltage levels, alternative circuital configurations for switch…
L'Orchestra di Auschwitz. Inchiesta su Alma Rosé
2023
Il libro è un'inchiesta sulla vita e il tempo di Alma Rosé (1906-1944), nipote di Gustav Mahler, debuttante e ragazza alla moda fra gli anni Venti e Trenta del secolo scorso, violinista il cui talento matura – paradossalmente – mentre l’ombra del nazismo si dispiega sull’Europa e infine direttrice dell’orchestra di Auschwitz. in un’epoca in cui la carriera del direttore d’orchestra era declinata soltanto al maschile. Giunta ad Auschwitz nell’estate 1943 e assegnata dapprima al Block degli esperimenti medici, Alma riuscì in breve tempo a diventare – nel piccolo mondo terribile del Lager – una specie di celebrità: ed è in quelle tenebre, d’altronde, che si svolge l’atto finale del dramma, oss…
Three-dimensional dynamic light scattering
1999
Abstract We describe the employment of a novel light-scattering scheme for the decorrelation of multiple scattering in strongly turbid samples. The three-dimensional scheme, which has been proposed already theoretically, shows certain advantages compared with the two-colour apparatus, which is commercially available. We describe our set-up in detail; features are the use of modern semiconductor laser diodes and contemporary single-mode fibre receivers. We show experimentally that the optimal signal-to-noise ratio (or intercept) β opt = 0.20, which is obtainable with our set-up, can be quantitatively calculated from the measured uncertainties in the alignment. In particular, we give a detail…
Effects of quantum statistics of phonons on the thermal conductivity of silicon and germanium nanoribbons.
2012
: We present molecular dynamics simulation of phonon thermal conductivity of semiconductor nanoribbons with an account for phonon quantum statistics. In our semiquantum molecular dynamics simulation, dynamics of the system is described with the use of classical Newtonian equations of motion where the effect of phonon quantum statistics is introduced through random Langevin-like forces with a specific power spectral density (color noise). The color noise describes interaction of the molecular system with the thermostat. The thermal transport of silicon and germanium nanoribbons with atomically smooth (perfect) and rough (porous) edges are studied. We show that the existence of rough (porous)…
Low-cost high-haze films based on ZnO nanorods for light scattering in thin c-Si solar cells
2015
Light scattering from ZnO nanorods (NR) is investigated, modeled, and applied to a solar cell. ZnO NR (120-1300 nm long, 280-60 nm large), grown by low-cost chemical bath deposition at 90 degrees C, exhibit diffused-to-total transmitted light as high as 70% and 30% in the 400 and 1000 nm wavelength range, respectively. Data and scattering simulation show that ZnO NR length plays a crucial role in light diffusion effect. A transparent ZnO NR film grown on glass and placed on top of a 1 mu m thick c-Si solar cell is shown to enhance the light-current conversion efficiency for wavelengths longer than 600 nm. (C) 2015 AIP Publishing LLC.