Search results for " ingegneria"

On the calculation of free energy of mixing for aqueous polymer solutions with group-contribution models

2010

Abstract Liquid–liquid phase separation processes are currently used as a route to prepare polymeric porous structures for various applications (membranes and scaffolds for tissue engineering). In membrane and foam fabrication technologies, binary and mainly ternary polymer solutions are used. Membrane morphology is strongly affected by phase equilibria of processing solution. In order to achieve a better control of membrane morphology and to explore a wide quantity of solvents, a predictive tool addressing experimentals would be strongly advisable. In this paper, group contribution models were chosen to test the applicability on a PLLA–dioxane–water ternary polymer solution, whose experime…

Photocatalytic oxidation of trans-ferulic acid to vanillin on TiO2 and WO3-loaded TiO2 catalysts

2015

Abstract The photocatalytic oxidation of trans-ferulic acid to vanillin in water has been studied by using various TiO2 and WO3-loaded TiO2 samples as catalysts. Different values of selectivity were obtained depending on the physico-chemical properties of the single samples and a vanillin selectivity of 10% was reached in the presence of the commercial TiO2 Merck. Higher selectivity values were obtained by impregnation of TiO2 with H2WO4 followed by calcination. The increased production of vanillin exhibited by the obtained WO3-loaded TiO2 powders was attributed to a reduced further oxidation of the aldehyde caused by the presence of the practically inactive tungsten trioxide hydrate on the…

No-Flow Temperature in Injection Molding Simulation

2010

Most injection molding simulation packages use the no-flow temperature (NFT) as a means of determining whether the polymer flows or is solid. The NFT is not well defined, and a standard method for measuring it does not exist. A sensitivity analysis of the filling stage has been carried out with two different packages [VISI Flow (Vero Software Limited, Gloucestershire, UK) and Moldflow (Autodesk, Inc., San Rafael, CA)] to estimate the influence of the NFT on the main processing parameters. The NFT has a large influence on the thickness of the frozen layer, but it does not appreciably affect the filling pressure. Because the NFT affects the frozen layer, an effect on the estimation of shrinka…

Wastewater modification processes in a stabilization reservoir: a new mathematical model

2018

The paper presents a mathematical model for the simulation of the ecology of a wastewater stabilization reservoir (WSR). WSRs are hypertrophic aquatic systems devoted to water storage in warm countries where shortage conditions are often encountered. Several factors that affect the stabilization reservoir’s effluent quality were taken into account: hydraulics and hydrology, solar radiation, reaeration, algae, zooplankton, organic matter, pathogens, and sediment-water interactions. The model quantifies the specific influence of each factor on effluent quality, and evaluating the correlation between the different factors. State variables included in the model were: algae, dissolved oxygen, or…

The use of master curves to describe the simultaneous effect of cooling rate and pressure on polymer crystallization

2003

In a previous work a master-curve approach was applied to experimental density data to explain isotactic polypropylene (iPP) behaviour under pressure and high cooling rates. Suitable samples were prepared by solidification from the melt under various cooling rate and pressure conditions with the help of a special apparatus based on a modified injection moulding machine. The approach here reported is more general than the case study previously shown, and is suitable to be applied to several materials and for different measures related to crystalline content. The proposed simple model is able to predict successfully the final polymer properties (density, micro-hardness, crystallinity) by supe…

Will collaborative partners’ selection enhance sustainability performance of firms? An empirical study

2015

Main purpose of this paper is to study the role of collaboration for sustainability, in success of business performance. Businesses can have collaborations with many players such as suppliers, logistics operators, clients, intra- and inter-departmental collaborations, for various purposes including the sustainability. We use qualitative approach, mainly semi-structured interviews to understand various dimensions of collaboration namely sharing of valuable information, physical resources both tangible and intangible. We try to understand the collaborative relationships of focal companies under study with its suppliers, buyers and logistics partners. Further, we will study the impact of colla…

How do different network positions affect crowd members' success in crowdsourcing challenges?

2023

In the crowdsourcing challenges, crowd members can interact with each other by, for example, chatting, exchanging feedback, providing advice, discussing, and commenting on ideas. These social interactions shape a network structure, which is a set of social relationships developed by crowd members. This study aims at investigating how occupying diverse network positions within a crowdsourcing challenge network increases the members' likelihood to succeed in a competition. Leveraging prior literature on social networks and crowdsourcing research, we theorize how central and structural hole network positions influence the crowd members' likelihood of winning crowdsourcing challenges by leverag…

‘To own or not to own?’ A study on the determinants and consequences of alternative intellectual property rights arrangements in crowdsourcing for in…

2018

Due to copyright restrictions, the access to the full text of this article is only available via subscription. Firms are increasingly engaging in crowdsourcing for innovation to access new knowledge beyond their boundaries; however, scholars are no closer to understanding what guides seeker firms in deciding the level at which to acquire rights from solvers and the effect that this decision has on the performance of crowdsourcing contests. Integrating property rights theory and the problem-solving perspective while leveraging exploratory interviews and observations, we build a theoretical framework to examine how specific attributes of the technical problem broadcast by firms affect the see…

Defensive behavior in healthcare: the role of organizational factors

Defensive medicine occurs when a healthcare practitioner performs treatment or procedure to avoid exposure to malpractice litigation. Being the consequences of such a behavior nefarious both in terms of patient care, healthcare operations and cost, much has been done in terms of research and practice with the aim to reduce the likelihood of its occurrence. Because defensive medicine is strictly related to the doctor perception of the risk of litigation and its legal repercussions, in the last years, jurisprudence and insurance contract studies in healthcare focused on this topic, as well as national laws have been introduced with the goal of contrasting it. This paper argues and demonstrate…

BIOLOGICAL DENITRIFICATION OF GROUNDWATER: BIO-PRB COLUMN TEST PERFORMANCES EVALUATION

2012

The occurrence of nitrates in groundwater is steadily raising concern due to possible health consequences of nitrate ingestion. Biological denitrification in BIO-PRB is the enhancement of a natural process that occurs naturally when bacteria live in an environment void of oxygen with carbon availability. Bio-PRB represent a perspective of development for PRB technique but, despite the fact that this technology has already been widely used for chlorinated solvents, data on denitrification PRBs are still scarce. This paper reports on the results of an experimental study carried out for 214 days on a bench-scale pilot column (10 cm in internal diameter and 100 cm in length with sampling ports …