Search results for "ingegneria"

Comparison of Two Mathematical Models for Greenhouse Gas Emission from Membrane Bioreactors

2017

In this study two mathematical models (Model I and Model II), able to predict the nitrous oxide (N2O) and carbon dioxide (CO2) emission from an University Cape Town (UCT) – membrane bioreactor (MBR) plant, have been compared. Model I considers the N2O production only during the denitrification. Model II takes into account the two ammonia-oxidizing bacteria (AOB) formation pathways for N2O. Both models were calibrated adopting real data. Results highlight that Model II had a better capability of reproducing the measured data especially in terms of N2O model outputs. Indeed, the average efficiency related to the N2O model outputs was equal to 0.3 and 0.38 for Model I and Model II respectively.

TAPPARELLA AVVOLGIBILE A SISTEMA DESMODROMICO

2017

La presente invenzione riguarda una tapparella avvolgibile a sistema desmodromico. La tapparella della presente invenzione è dotata di un meccanismo che consente l'apertura delle lamelle sfruttando il peso stesso della tapparella. L'apertura delle lamelle viene attuata grazie alla particolare geometria del meccanismo e mediante l'interazione tra le guide e le parti scorrevoli della tapparella. La sua geometria riesce a determinare l’apertura o la chiusura delle lamelle. The present invention relates to a roller shutter with a desmodromic-system. The shutter of the present invention is provided with a mechanism allowing the slats to be opened by exploiting the weight of the blind itself. The…

The sludge dewaterability in advanced wastewater treatment: a survey of four different Membrane BioReactor pilot plants

2017

The wasted activated sludge dewaterability represents a major concern for Wastewater Treatment Plants (WWTPs) managers. Indeed, whereas the dewatered sludge could represents a re-usable matrix, the principal drawback related to the wasted sludge dewaterability is the high water content due to the presence of extracellular polymeric substances (EPS) that allow the trapping of water molecules within the bio sludge flocs. In order to provide an outlook of the dewaterability features of activated sludge derived from advanced WWTP, the present research reports a long term survey (over two years) aimed at assessing the principal dewaterability parameters of the sludge wasted from different Membra…

An experimental methodology to study polymer crystallization under processing conditions. The influence of high cooling rates

2002

Abstract A new experimental route for investigating polymer crystallization under very high cooling rates (up to 2000°C/s) is described. A complete and exhaustive description of the apparatus employed for preparing thin quenched samples (100– 200 μm thick) is reported, the cooling mechanism and the temperature distribution across sample thickness is also analysed, showing that the final structure is determined only by the thermal history imposed by the fast quench apparatus. Details concerning the characterization techniques used to probe the final structure are reported, including density measurements and wide angle X-ray diffraction patterns. Experimental results concerning isotactic poly…

The continuous cooling transformation (CCT) as a flexible tool to investigate polymer crystallization under processing conditions

2009

An experimental route for investigating polymer crystallization over a wide range of cooling rates (from 0.01 to 1000◦C/s) and pressures (from 0.1 to 40 MPa) is illustrated, using a method that recalls the approach adopted in metallurgy for studying structure development in metals. Two types of experimental setup were used, namely an apparatus for fast cooling of thin films (100–200 μm thick) at various cooling rates under atmospheric pressure and a device (based on a on-purpose modified injection molding machine) for quenching massive samples (about 1–2 cm3) under hydrostatic pressure fields. In both cases, ex situ characterization experiments were carried out to probe the resulting struct…

Isotactic polypropylene solidification under pressure and high cooling rates. A master curve approach

2000

Solidification in industrial processes very often involves flow fields, high thermal gradients and high pressures: the development of a model able to describe the polymer behavior becomes complex. Recently a new equipment has been developed and improved to study the crystallization of polymers when quenched under pressure. An experimental apparatus based on a modified, special injection moulding machine has been employed. Polymer samples can be cooled at a known cooling rate up to 100 °C/s and under a constant pressure up to 40 MPa. Density, Micro Hardness (MH), Wide angle X-ray diffraction (WAXD), and annealing measurements were then used to characterize the obtained sample morphology. Res…

In Vitro Measurement of Strain Localization Preceding Dissection of the Aortic Wall Subjected to Radial Tension

2020

AbstractBackgroundAortic dissection (AD) is a common pathology and challenging clinical problem. A better understanding of the biomechanical effects preceding its initiation is essential for predicting adverse events on a patient-specific basis. Moreover, the predictability of patient-specific biomechanics-based computational models is hampered by uncertainty about boundary conditions and material properties.ObjectivePredisposition of thoracic aortic aneurysms (TAA) to ADs can be related to the degradation of biomechanically important constituents in the aortic wall of TAAs. The goal of the present study is to develop a new methodology to measure strain fields in aortic tissues subjected to…

Industry 4.0 transition: a systematic literature review combining the absorptive capacity theory and the data–information–knowledge hierarchy

2021

Purpose The effect of the transition toward digital technologies on today’s businesses (i.e. Industry 4.0 transition) is becoming increasingly relevant, and the number of studies that have examined this phenomenon has grown rapidly. However, systematizing the existing findings is still a challenge, from both a theoretical and a managerial point of view. In such a setting, the knowledge management (KM) discipline can provide guidance to address such a gap. Indeed, the implementation of fundamental digital technologies is reshaping how firms manage knowledge. Thus, this study aims to critically review the existing literature on Industry 4.0 from a KM perspective. Design/methodology/approach …

LA PRODUZIONE DI PERCOLATO E DEL BIOGAS NELLE DISCARICHE CONTROLLATE: ANALISI CON MODELLI MATEMATICI E FISICI

Production Planning in Production Networks: Models for Medium and Short-term Planning

2008

Distributed production networks are structures which are considered able to provide the organisational agility and efficiency necessary to compete in the global market. The performance of such organisations heavily depends on the ability of those involved in the network to coordinate their activities. Two approaches are available for managing complex distributed production networks: a centralised approach, where a unique entity (the planner, for instance) has all the necessary information to make planning decisions for the entire network; or a decentralised approach where each entity in the network has the necessary information and knowledge to make autonomous planning decisions, while the …