Search results for "renewable resources"

Undecylenic acid: A tunable bio-based synthon for materials applications

2016

International audience; An undecylenic acid-based monoglyceride prepared from glycidol and undecylenic acid is used as suitable and tunable synthon for polymerization applications. Epoxidation and acrylation reactions lead to photopolymerizable monomers while transesterification with dimethyl carbonate, metathesis and aminolysis reactions provide access to polyhydroxyurethane-based materials. The successive intermediates were synthesized according to a green chemistry approach implicating solvent-less and catalyzed reactions, and were at each step fully characterized by infrared, 1H and 13C{1H} NMR spectroscopy, elemental analysis and mass spectrometry. Analyses of the resulting polymer mat…

Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption

2015

The oxidative degradation of lignin into a variety of valuable products has been under investigation since the first half of the last century. Especially, the chance to claim this cheap, abundant and renewable source for the production of the important aroma chemical vanillin (1) was one of the major driving forces of lignin research. So far most of the developed methods fail in technical application since no viable concept for work-up is included. This work represents a combined approach of electrochemical conversion of Kraft lignin and product recovery by adsorption on a strongly basic anion exchange resin. Electrolysis conditions are optimized regarding reaction temperatures below 100 °C…

Facile and efficient chemical functionalization of aliphatic polyesters by cross metathesis

2016

International audience; An effective preparation of new tailor-made macromolecular materials via a combination of two (atom-efficient) catalytic transformations is reported. First, new aliphatic polyesters with alternated composition have been prepared using a salen aluminum catalyst system. Next, the pendant vinyl moieties in those copolymers have been selectively transformed into various functional groups by metathesis in the presence of homogeneous Grubbs catalysts. The latter metathesis reaction has been optimized in terms of catalytic activity and selectivity, to define the conditions for an effective and safe procedure that does not affect the macromolecular architecture. All polymer …

Un procedimiento de fuerte reducción de las dimensiones del RCPS/π

2009

Recently, in the field of project scheduling problems the concept of partially renewable resources has been introduced. Theoretically, it is a generalization of both renewable and non-renewable resources. From an applied point of view, partially renewable resources allow us to model a large variety of situations that do not fit into classical models, but can be found in real problems in timetabling and labour scheduling. When modelling real problems, the problem of project scheduling with partially renewable resources, as many other combinatorial problems, gets such large dimensions that it is quite difficult to apply solution procedures. In this paper, we describe some powerful preprocessi…

GRASP and path relinking for project scheduling under partially renewable resources

2008

[EN] Recently, in the field of project scheduling problems the concept of partially renewable resources has been introduced. Theoretically, it is a generalization of both renewable and non-renewable resources. From an applied point of view, partially renewable resources allow us to model a large variety of situations that do not fit into classical models, but can be found in real problems in timetabling and labor scheduling. In this paper, we develop some preprocessing techniques and several heuristic algorithms for the problem. Preprocessing significantly reduces the dimension of the problems, therefore improving the efficiency of solution procedures. Heuristic algorithms based on GRASP an…

On Capturing Oil Rents with a National Excise Tax Revisited

2004

In this paper the scope of Bergstrom’s (1982) results is studied. Moreover, his analysis is extended assuming that extraction cost is directly related to accumulated extractions. For the case of a competitive market it is found that the optimal policy is a constant tariff if extraction is costless. However, with depletion effects, the optimal tariff must ultimately be decreasing. For the case of a monopolistic market the results depend crucially on the kind of strategies the importing country governments can play and on whether the monopolist chooses the price or extraction rate. For a price-setting monopolist it is shown that the importing countries cannot use a tariff to capture monopoly …

RENEWABLE ENERGY AND INNOVATION FOR SUSTAINABLE GREENHOUSE DISTRICTS

2009

Long-term properties and end-of-life of polymers from renewable resources

2017

[EN] The long-term properties and end-of-life of polymers are not antagonist issues. They actually are inherently linked by the duality between durability and degradation. The control of the service-todisposal pathway at useful performance, along with low-impact disposal represents an added-value. Therefore, the routes of design, production, and discarding of bio-based polymers must be carefully strategized. In this sense, the combination of proper valorisation techniques, i.e. material, energetic and/ or biological at the most appropriate stage should be targeted. Thus, the consideration of the end-of-life of a material for a specific application, instead of the end-of-life of a material s…

La Seconda Vita dell'Ambiente Costruito

2021

Il contributo inquadra i saggi, gli studi, le ricerche e progetti pubblicati sul numero 9 di AGATHÓN su ‘La Seconda Vita dell’Ambiente Costruito’, tema di interesse per il mondo accademico, delle professioni e dell’industria. Cambiamenti climatici, eccessivo consumo di suolo e di risorse non rinnovabili, produzione sempre crescente di rifiuti, emergenza pandemica e crisi socio-economica globale sono entrati di fatto nel nostro quotidiano: seppur drammatiche, per certi versi, tali questioni possono essere colte come un’opportunità per ripensare il modo e il mondo in cui viviamo. In questo contesto di ‘rivoluzione’(Floridi, 2020) e di ‘policrisi’ (Losasso, 2020), e con riferimento specifico a…

A methodological approach for assessing businness investments in renewable resources from a circular economy perspective

2018

Abstract In this paper, we have analyzed a feasibility project for the realization of a biogas plant at a company in the viticulture sector located in south-central Sicily. Using engineering formulas, we identified the electrical power that the plant could produce using waste products created by the vineyard itself, examined the new and interesting opportunities that have arisen with the encouragement and development of biogas production in Italy, and then assessed the economic feasibility of the investment itself, considering an investment scheme of total capital self-financing. The possibility of using wastes from wine production comes from an in-depth study of the circular economy, that …