IRIS - UNIRSM (Univ. degli Studi della Repubblica di San Marino)
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Modeling and numerical investigation of the viscoelastic behavior of laminated concrete beams strengthened by CFRP strips and carbon nanotubes
No full textThe paper aims to prove that the application of innovative constituents and materials can noticeably affect the mechanical behavior of structures. The research is focused on the long-time behavior of concrete beams reinforced by Carbon Fiber Reinforced Polymer (CFRP) strips applied on their external surfaces. The concrete and the CFRP are both characterized by time-dependent mechanical features according to the theoretical framework provided by the linear viscoelasticity. Their properties are described through the introduction of the proper creep functions. The reinforcing strips are made of a polymer matrix reinforced by straight long Carbon fibers and randomly oriented Carbon nanotubes (CNTs). Due to the presence of two reinforcing phases at different levels (nano- and micro-scale), a multiscale model is introduced to compute the global mechanical properties of these innovative composites. Their characterization at the nano-scale is accomplished through the Eshelby-Mori-Tanaka scheme, whereas the Hanh approach provides the overall engineering constants of the CFRP strips. The Timoshenko beam theory for laminated beams is employed to describe the mechanical behavior of the structures. A numerical solution is developed to achieve the time dependency of central deflections and the redistribution of stresses along the thickness of the layered structures. Several responses are investigated to show also the effect of the mass fraction of CNTs, the thickness and the number of CFRP strips. The results presented in this paper could be taken into account to improve the structural response of concrete beams in contrasting the creep phenomenon due to the intrinsic nature of the material
CR4056, a powerful analgesic imidazoline‐2 receptor ligand, inhibits the inflammation‐induced PKCε phosphorylation and membrane translocation in sensory neurons
Get PDFBackground and purpose: CR4056 is a first-in-class imidazoline-2 (I2 ) receptor ligand characterized by potent analgesic activity in different experimental animal models of pain. In a recent phase II clinical trial, CR4056 effectively reduced pain in patients with knee osteoarthritis. In the present study, we investigated the effects of CR4056 on PKCε translocation in vitro and on PKCε activation in vivo in dorsal root ganglia (DRG) neurons. Experimental approach: Effects of CR4056 on bradykinin-induced PKCε translocation were studied in rat sensory neurons by immunocytochemistry. PKCε activation was investigated by immunohistochemistry analysis of DRG from complete Freund's adjuvant-treated animals developing local hyperalgesia. The analgesic activity of CR4056 was tested on the same animals. Key results: CR4056 inhibited PKCε translocation with very rapid and long-lasting activity. CR4056 decreased hyperalgesia and phospho-PKCε immunoreactivity in the DRG neurons innervating the inflamed paw. The effect of CR4056 on PKCε translocation was blocked by pertussis toxin, implying that the intracellular pathways involved Gi proteins. The inhibition of PKCε translocation by CR4056 was independent of the α2 -adrenoeceptor and, surprisingly, was also independent of idazoxan-sensitive I2 binding sites. The I2 agonist 2BFI had no effect alone but potentiated the activity of low concentrations of CR4056. Conclusions and implications: Our results demonstrate that CR4056 shares the ability to inhibit PKCε translocation with other analgesics. Whether the inhibition of PKCε involves binding to specific subtype(s) of I2 receptors should be further investigated. If so, this would be a new mode of action of a highly specific I2 receptor ligand
A TOPSIS-based approach for the best match between manufacturing technologies and product specifications
No full textWhen manufacturing a product, companies must consider the specifications of its design and choose the manufacturing technology that matches them the best in terms of product quality, production time and costs. Since all these parameters can be represented by several different and conflicting indicators, the problem of technology selection can be defined as a multi-criteria decision-making (MCDM) problem. Although several mathematical models have been developed to solve similar problems, recent literature still presents a lack of specific applications of renowned decision-making techniques to the technology matching problem in the manufacturing sector. This study attempts to fill this gap by proposing a manufacturing-oriented model of the Technique for Order Preference by Similarity to Ideal Solutions (TOPSIS), one of the most solid and robust MCDM methods. The solution we present, which is designed for general manufacturing processes, has been applied to the specific case of a producer of food and beverage plants and equipment that is interested in reengineering one of its products. Due to the complexity of the food and beverage industry, the case study is useful for supporting the definition of the general model and validating its applicability. Further, the results of the specific application prove the effectiveness of our model
Dalla direttiva 89/391/CEE alle norme nazionali
No full textIl saggio descrive da un punto di vista giuridico la portata e le conseguenze del d.lgs. n. 81/2008, discutendone la coerenza con la direttiva europea 89/391 ed evidenziando le problematiche dell’attuale normativa
Lab networks in engineering education: A proposed structure for organizing information
No full textExperimentation plays an essential role in engineering education, allowing to balance theoretical proofs and emphasis on physical intuition. Laboratories can fulfil several goals at once, but they also involve high costs, mostly due to equipment, space, and human resources for operating and maintaining them. Remote-access labs have been proposed as a feasible alternative: developed since the early 2000s by an ever-increasing research community, they are real or virtual labs accessible at distance through a computer network. Recently, alternative bibliometric taxonomies and classifications of current networked remote-access labs have been proposed. Yet, none of these works proposes a comprehensive structure to collect and organize the information, especially from a technical perspective, aiming at the definition of the state of the art and future outlooks of provided solutions. In the present work, we fill this gap extending previous works by enlarging their set of criteria towards a general multi-layer model for networked remote-access labs. We performed a systematic review of relevant literature to retrieve useful information and to design the data collection and classification structure, which is finally validated performing a mini-Delphi method
The milk collection problem with time constraint: An optimization study integrating simulation
No full textTransport management and vehicle routing problems play a strong role on a company's efficiency and competitiveness. In the food sector, the complexity of the problem grows because of strict constraints. This paper addresses the dairy transportation problem and in particular tries to optimize the milk collection process of a real company. A two-step approach has been proposed to test the current system and solve the routing problem. First, starting from the “As is” collection tours, a travel salesman problem has been modelled. Later, the Nearest Neighbor algorithm has been implemented in order to find a global optimal solution. Finally, a stochastic simulation model integrates the solutions of the previous step in order to test the feasibility of the outcomes, primarily in terms of their capability to meet the time constraints of the tours. Results show that the greedy approach allows less vehicles to be involved, with a good potential on annual cost saving. On the other hand, the simulation outcomes highlight a borderline case, which is not always in line with the time constraints of the problem
