Search results for "Pension"
showing 10 items of 513 documents
Measurements of Njs and Power Requirements in Unbaffled Bioslurry Reactors
2012
The remediation of urban/industrial polluted lands is a topic of crucial importance nowadays. Bioremediation techniques are widely employed to remove organic pollutants from contaminated soils because of their simplicity and cheapness. The bioslurry reactors mechanically agitated by stirrers represent one of the most promising bioremediation techniques. In the present work an unbaffled stirred vessel filled with solids and water is experimentally investigated from a fluid dynamic point of view. Air presence within the tank is guaranteed by the central vortex formation (typical occurrence concerning stirred vessels unprovided with baffles) instead of an intrinsically more expensive insufflat…
Power requirements for complete suspension and aeration in an unbaffled bioslurry reactor
2016
Remediation of contaminated soils is spreading as a matter of crucial importance nowadays. Bioremediation via bioslurry reactors of sites polluted by recalcitrant pollutants has been proved to be a valuable option, although optimization is needed to reduce process costs. Free-surface unbaffled stirred tanks (with central air vortex) have been recently proposed as a promising alternative to the more common systems provided with baffles. In a bioslurry reactor solid-liquid interfacial area, oxygen supply, solid loading per reactor unit volume should be maximized, and, at the same time, operation costs have to be kept low. In this regard, the minimum impeller speeds for complete suspension Njs…
CFD prediction of solid particle distribution in baffled stirred vessels under partial to complete suspension conditions
2013
Solid-liquid mixing within tanks agitated by stirrers can be easily encountered in many industrial processes. It is common to find an industrial tank operating at an impeller speed N lower than the minimum agitation speed for the suspension of solid particles: under such conditions the distribution of solid-particles is very far from being homogeneous and very significant concentration gradients exist. The present work evaluates the capability of a Computational Fluid Dynamics (CFD) model to reliably predict the particle distribution throughout the tank under either partial or complete suspension conditions. A flat bottomed baffled tank stirred by a Rushton turbine was investigated. Both tr…
Comparison of Agitators Performance for Particle Suspension in Top-Covered Unbaffled Vessels
2015
Power savings is a problem of crucial importance nowadays. In process industry, suspension of solid particles into liquids is usually obtained by employing stirred tanks, which often are very power demanding. Notwithstanding tanks provided with baffles are traditionally adopted for this task, recent studies have shown that power reductions can be obtained in top-covered unbaffled vessels. In the present work experiments were carried out in a top-covered unbaffled vessel with a diameter T=0.19m and filled with distilled water and silica particles. Two different turbines were tested: a standard six-bladed Rushton Turbine (RT) and a 45° four bladed Pitched Blade Turbine (PBT). For the case of …
CFD Predictions of Sufficient Suspension Conditions in Solid-Liquid Agitated Tanks
2012
Abstract Most research efforts on mechanically agitated solid-liquid contactors have been devoted to the assessment of the minimum impeller speed for complete off-bottom suspension, N js . Actually, many industrial vessels are operated at impeller speeds slightly lower than N js (Oldshue, 1983; Rieger et al., 1988). This suggests that the sufficient suspension condition, which is quantitatively specified in this paper by introducing a suitably defined quantity N ss , may represent a valid alternative to that of complete suspension. In the present work time-dependent RANS simulations were carried out with the aim of predicting the achievement of sufficient suspension conditions. The Eulerian…
Anticipo de jubilación en Italia: entre sustenibilidad financiera y solidaridad intergeneracional
2019
The essay focuses on the recent reform of the Italian pensions system ("quota cento") and it puts in evidence the criticalities of the reform having regard to its financial sustainability and to the principle of intergenerational solidarity. El ensayo analiza la reciente reforma al sistema de pensiones italiano ("quota cento") subrayando sus criticidades desde la doble vertiente de la sustenibilidad financiera y de la solidaridad intergeneracional.
L’INCIDENTE PENALE NEL SISTEMA DISCIPLINARE DELL’IMPIEGO PUBBLICO PRIVATIZZATO: PROCEDURE, RACCORDI, MISURE CAUTELARI
2020
Il saggio esamina l’attuale disciplina dei rapporti tra procedimento penale e procedimento disciplinare nell’impiego pubblico privatizzato, mettendo in evidenza i principali problemi interpretativi – e le relative soluzioni applicative – che conseguono al superamento della “pregiudiziale penale”, in favore del principio della separazione fra giudizi. L’analisi si sviluppa attraverso la ricostruzione della disciplina di fonte legale e del suo intreccio con le regole integrative dettate dall’autonomia collettiva nella più recente tornata contrattuale. Particolare attenzione è dedicata all’istituto della sospensione cautelare e al problema della restitutio in integrum spettante al lavoratore i…
Clausole di risoluzione automatica del rapporto, mutuo consenso e aliunde perceptum
2014
Sulla forma del recesso ad nutum nei confronti della lavoratrice pensionata per raggiunti limiti di età
2006
Il contributo analizza la disciplina del licenziamento di lavoratore che ha raggiunto l'eta pensionabile