Search

Your search keyword '"Nasri, Moncef"' showing total 1,235 results
Start Over Author "Nasri, Moncef"
1,235 results on '"Nasri, Moncef"'

15. Route and speed optimization problems under uncertainty and environmental concerns

Author

Nasri, Moncef Ilies and Bektas, Tolga

Subjects
658
Abstract

This thesis studies logistics problems with the overall aim to reduce the emission of greenhouse gases. These problems are formalized, modeled and solved to derive useful insight for both logistics companies and policy makers. Chapter 1 introduces the background, presents the research aims and objectives as well as the research context. Chapter 2 studies The Pollution-Routing Problem under traffic uncertainty. The problem assumes uncertain traffic conditions and aims at reducing the cost of emissions, fuel consumption and travel times. Stochastic programming has been used to propose new mathematical models capable of considering traffic conditions as a discrete set of random scenarios. Extensive computational experiments are carried out, to quantify the savings yielded by the stochastic approach over a deterministic approach, and by controlling speed. Chapter 3 reconsiders the problem dened in Chapter 2. However, instead of solving it with commercial solvers, new solution techniques based on decomposition, and more precisely integer L-shaped algorithm that uses cuts, lower-bounds and local-branching are proposed. Chapter 4 focuses on the speed optimization problem that consists of choosing the optimal speed on each leg of a given vehicle route represented by a fixed sequence of customers. The objective function accounts also for the pollution emitted by the vehicles. Each customer in the sequence has a service time window. Early and late starts of service are allowed, but at the expense of penalties. A natural model of the problem in the form of a non-linear program is presented, which is then linearized in several ways. Several algorithms are described based on the use of time-space networks. Managerial insight is derived for maritime and road transportation. Chapter 5 concludes by summarizing the key findings and contributions of this thesis, discusses the limitations of this work and suggests future directions of research.

Published
2018

18. Chapter Eight - Food applications of bioactive biomaterials based on gelatin and chitosan.

Author

Jridi, Mourad, Abdelhedi, Ola, Salem, Ali, Zouari, Nacim, and Nasri, Moncef

Abstract

Food packaging must guarantee the products' quality during the different operations including packing and maintenance throughout transportation and storage until to consumption. Thus, it should satisfy, both, food freshness and quality preservation and consumers health safety. Natural bio-sourced polymers have been explored as safe edible materials for several packaging applications, being interestingly carrier of bioactive substances, once added to improve films' properties. Gelatin and chitosan are among the most studied biomaterials for the preparation of edible packaging films due to their excellent characteristics including biodegradability, compatibility and film-forming property. These polymers could be used alone or in combination with other polymers to produce composite films with the desired physicochemical and mechanical properties. When incorporated with bioactive substances (natural extracts, polyphenolic compounds, essential oils), chitosan/gelatin-based films acquired various biological properties, including antioxidant and antimicrobial activities. The emerging bioactive composite films with excellent physical attributes represent excellent packaging alternative to preserve different types of foodstuffs (fruits, meat, fish, dairy products, ...) and have shown great achievements. This chapter provides the main techniques used to prepare gelatin-and chitosan- based films, showing some examples of bioactive compounds incorporated into the films' matrix. Also, it illustrates the outstanding advantages given by these biomaterials for food preservation, when used as coating and wrapping agents. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results