87,210 research outputs found
Metal catalysis in oxidation by peroxides. Part 191 1 Part 18: O. Bortolini, V. Conte, F. Di Furia and G. Modena, J. Mol. Catal., 19 (1983) 331.. On the mechanism of rhodium-catalyzed oxidation of terminal olefins to methyl ketones by dioxygen
No full textThe mechanism of the rhodium-catalyzed oxidation of oct-1-ene to octan-2-one by dioxygen in ethanol has been investigated by deuterium labelling studies, employing ethanol-d1 and [2-2H]oct-1-ene respectively. In both sets of experiments, substantial label exchange with the solvent has been observed, suggesting a decomposition pathway for the peroxometallocycle intermediate which does not involve a β-hydride shift. © 1984
Bi-objective design of sustainable reconfigurable manufacturing systems
No full textReconfigurable Manufacturing Systems (RMSs) rose as advanced production systems able to meet the current market challenges rapidly changing their physical and logical structure. An RMS environment is usually characterized by intelligent machines called Reconfigurable Machine Tools (RMTs), consisting of fixed parts, i.e. the basic modules, and dynamic changeable parts, i.e. the auxiliary modules, which allow performing different tasks. The literature is rich in studies proposing methodologies for RMS design and management optimizing their operative and economic performances. Studies including the environmental sustainability perspective are still limited. To fill this gap, this paper proposes and applies a bi-objective mathematical model for the RMS design and management, optimizing the operative performances from one side, i.e. by minimizing the parts’ and auxiliary modules’ travel time and the RMT reconfiguration time, and the environmental performances from the other side, i.e. by minimizing the energy consumption for the part processing and the RMT reconfiguration. The application of the bi-objective model to an operative industrial case study showcases how to best balance operative and environmental objectives. The selected trade-off point allows a significant improvement of both time and energy performances compared to their worst values, rising as an efficient production system configuration
Asymmetric Oxidation of Beta-hydroxysulfides - the Role of the Hydroxy Group
No full textIn the asymmetric oxidation of prochiral β-hydroxysulfides to the corresponding sulfoxides, by using a recently developed modified Sharpless reagent, it has been observed that the presence of the hydroxy group in the molecule of the substrate is not playing a significant role in determining the extent of the enantioselection, at variance with the asymmetric epoxidation of allylic alcohols where formation of alkoxytitanium complexes is believed to be a crucial process, thus indicating some important difference in the oxidation mechanisms
Accelerating life testing for food packaging. A case study of Italian oil-for-food distribution
No full textAccelerating life testing analyses deal with products subject to failure and stressed over
nominal operating conditions in order to quickly capture reliability parameters under stress
and indirectly estimate them during nominal conditions. A few studies have been
conducted on accelerating life testing applied to packaging design. Literature does not
present results on the measurement of the effects of temperature, the typical stress
parameter, on different bottles of oil for food. The food packages can differ for the content of
the bottle, e.g. extra virgin olive oil, rice oil and vinacciolo oil, for the type of bottle (e.g.
glass or plastic), for the closure adopted (plastic or aluminium caps) or the
presence/absence of the cap cover. For different combinations of these factors an expected
value of life duration given a specific stress value, also including the use/nominal operating
stress, can be estimated. A case study is illustrated and the obtained results for different
packages are discussed
Crowd Logistics: A Survey of Successful Applications and Implementation Potential in Northern Italy
No full textNowadays, last-mile logistics represents the least efficient stage of supply chains, covering up to 28% of the total delivery cost and causing significant environmental emissions. In the last few years, a wide range of collaborative economy business models has emerged across the globe, rapidly changing the way services were traditionally provided and consumed. Crowd logistics (CL) is a new strategy for supporting fast shipping services, entrusting the management of the last-mile delivery to the crowd, i.e., normal people, who agree to deliver goods to customers located along the route they have to travel, using their own transport means, in exchange for a small reward. Most existing studies have focused on evaluating the opportunities and challenges provided by CL through theoretical analysis and literature reviews, while others have proposed models for designing such emerging distribution networks. However, papers analyzing real successful applications of CL worldwide are lacking, despite being in high demand. This study attempted to fill this gap by providing, at first, an overview of real CL applications around the globe to set the stage for future successful implementations. Then, the implementation potential of CL in northern Italy was assessed through a structured questionnaire delivered to a panel of 214 people from the Alma Mater Studiorum University of Bologna (Italy) to map the feasibility of a crowd-based system in this area. The results revealed that about 91% of the interviewees were interested in using this emerging delivery system, while the remaining respondents showed some concern about the protection of their privacy and the safeguarding of the goods during transport. A relevant percentage of the interviewees were available to join the system as occasional drivers (ODs), with a compensation policy preference for a fixed fee per delivery rather than a variable reward based on the extra distance traveled to deliver the goods
Determination of absolute configuration using vibrational circular dichroism spectroscopy: Phenyl glycidic acid derivatives obtained via asymmetric epoxidation using oxone and a keto bile acid
No full textThe (+)-enantiomers of the o-Br, m-F and p-CH3 derivatives of trans phenyl glycidic acid have been obtained from the
corresponding trans cinnamic acid derivatives using Oxone and the tri-keto bile acid dehydrocholic acid. Vibrational circular dichroism
(VCD) spectroscopy of their methyl esters has been used to determine their absolute configurations. In each case, the absolute
configurations of both methyl ester and parent acid were shown to be (2S,3R)-(+)/(2R,3S)-()
Optimizing Makespan in Single-Model Assembly Lines with Human-Robot Collaboration
No full textWithin the framework of the industry 4.0, robotics plays a crucial role, leading to a widespread diffusion of Collaborative Robots (Cobots). Cobots can work alongside human operators, focusing on tasks with a high biomechanical risk. However, the design of workstations in which humans and cobots can perform tasks in collaboration poses new challenges. In such a scenario, models for manual and automated assembly line design need to include both humans and cobots able to perform the same task in the same station. In addition, contributions assessing the influence of cobots introduction on the assembly line makespan are missing and expected. To fill this gap, this study proposes a mathematical optimization model to design a single-model assembly line. The evaluation of the minimum achievable makespan is carried out by considering different line configuration scenarios, starting from a fully manual assembly line up to including one cobot per station. The main results show that the use of cobots leads to significant time benefits, at the expense of a weak load balancing among the assembly workstations, paving the way for future studies aiming to explore such clear diverging trends
Reti logistico-distributive. Una piattaforma software integrata
No full textLa configurazione e l’organizzazione
di un network logistico-distributivo in
complesse realtà industriali impattano
s igni f icat i vamente sul l i vel lo di
competitività e sul conseguimento di
una posizione di vantaggio competitivo e
sostenibile con cui dette imprese operano
nel mercato globale. In questo contesto la
progettazione e la pianificazione strategica
della rete logistica, la configurazione
tattica della stessa, e la gestione e il
controllo operativi dei processi e dei
servizi, dal confezionamento e stivaggio
della merce a magazzino al carico dei
mezzi di trasporto e al loro instradamento
lungo la rete di traffico stradale e/o al
L’Università di Bologna ha completato una piattaforma
software di supporto all a progettazione, gestione e
ottimizzazione integrata dell a supply chain.
Distribuzione
Riccardo Manzini, Marco Bortolini, Emilio Ferrari, Mauro Gamberi
Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche
e di Metallurgia, Università di Bologna
44
ricorso di alternative modalità di trasporto
(rotaia, aereo, mare, fluviale, ...),
assumono un’importanza cruciale per il
successo di un’impresa.
A questo scopo il dipartimento di
Ingegneria delle Costruzioni Meccaniche,
Nucleari, Aeronautiche e di Metallurgia
dell’Università di Bologna, ha completato
lo sviluppo della piattaforma software
LD - LogOptimizer. Si tratta di un set di
strumenti di supporto alla progettazione,
ottimizzazione e gestione integrata di
una rete logistica distributiva multilivello,
in presenza cioè di più impianti
produttivi, centri di stivaggio e distributivi
delocalizzati, grossisti, dettaglianti e
clienti. Questa piattaforma è il risultato
della lunga esperienza condotta dai
ricercatori e professori dell’Università di
Bologna e dello sviluppo di un framework
logico e concettuale di riferimento basato
su un approccio sistemico, testato più
volte sul campo, dal settore alimentare
alla ceramica passando attraverso la
produzione di macchine automatiche e la
gestione dei ricambi, mediante il ricorso a
strumenti di mixed integer programming,
cluster analysis, algoritmi euristici, tools
di georeferenziazione, etc
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