Advances in centerless grinding

La lavorazione di rettifica senza centri a tuffo \ue8 un processo ad alta produttivit\ue0 ma che pu\uf2 soffrire di instabilit\ue0 e condizioni mutevoli, dovuti alla propria configurazione geometrica e alle caratteristiche degli utensili abrasivi. Il presente lavoro si propone di presentare un approccio pratico alla scelta dei parametri di processo con uno studio sperimentale dei loro effetti sulle caratteristiche qualitative tipiche di questa lavorazion

Assembling The Future: The Role Of Transactive Planning Theory In Generating Alternative Urban Strategies

Conditions of uncertainty, rapid change and heightened social, economic and spatial inequalities are symptomatic of an Increasingly Internationalised and urbanised world system. These issues correspond to the emergence of an urban problematic that requires the requalification of planning’s tools and techniques. Within this context: How does planning go about assembling the future? The Mont Fleur civic scenarios undertaken in South Africa (1991-1992), the Toekomstverkenningen Amsterdam (1998-1999), and the Bishopsgate Methodology Statement proposed for an inner-city development site in London (2002), are presented as illustrative examples of how, planning connects knowledge to action in the public domain, translates complexity, deals with the future; Do the tools and processes used in the examples, extend or limit the possibility of alternative urban strategies? These questions, are a starting point from which to explore John Friedmann’s theory on Transactive Planning (1973). This theory is defined as a normative response to improving the practice of plannirig through a dialogical process that combines various forms of technical and experiential knowledge, through which a deeper understanding of issues surrounding a particular problem, is achieved. Within the present research framework. Transactive Planning is used to formulate the principles, tools and techniques of an approach corresponding to the conditions of an urban problematic. The final question: ‘What kind of future do we want to assemble?” opens the discussion towards considering the role, not only of Transactive Planning, but of an urban imaginary as a way of rephrasing the urban problematic. The endgame is to refunction the notion of the future, not as “uncertainty” that has to be resolved, but as a creative process that generates innovative urban strategies

Nonreplicating synthetic mRNA vaccines: A journey through the European (Journal of Immunology) history

The first worldwide article reporting that injections of synthetic nonreplicating mRNA could be used as a vaccine, which originated from a French team located in Paris, was published in the European Journal of Immunology (EJI) in 1993. It relied on work conducted by several research groups in a handful of countries since the 1960s, which put forward the precise description of eukaryotic mRNA and the method to reproduce this molecule in vitro as well as how to transfect it into mammalian cells. Thereafter, the first industrial development of this technology began in Germany in 2000, with the founding of CureVac, which stemmed from another description of a synthetic mRNA vaccine published in EJI in 2000. The first clinical studies investigating mRNA vaccines in humans were performed as collaboration between CureVac and the University of Tübingen in Germany as early as 2003. Finally, the first worldwide approved mRNA vaccine (an anti‐COVID‐19 vaccine) is based on the mRNA technologies developed by BioNTech since its 2008 foundation in Mainz, Germany, and earlier by the pioneering academic work of its founders. In addition to the past, present, and future of mRNA‐based vaccines, the article aims to present the geographical distribution of the early work, how the development of the technology was implemented by several independent and internationally distributed research teams, as well as the controversies on the optimal way to design or formulate and administer mRNA vaccines

On the wave bottom shear stress in shallow depths: The role ofwave period and bed roughness

Lagoons and coastal semi-enclosed basins morphologically evolve depending on local waves, currents, and tidal conditions. In very shallow water depths, typical of tidal flats and mudflats, the bed shear stress due to the wind waves is a key factor governing sediment resuspension. A current line of research focuses on the distribution of wave shear stress with depth, this being a very important aspect related to the dynamic equilibrium of transitional areas. In this work a relevant contribution to this study is provided, by means of the comparison between experimental growth curves which predict the finite depth wave characteristics and the numerical results obtained by means a spectral model. In particular, the dominant role of the bottom friction dissipation is underlined, especially in the presence of irregular and heterogeneous sea beds. The effects of this energy loss on the wave field is investigated, highlighting that both the variability of the wave period and the relative bottom roughness can change the bed shear stress trend substantially

Characterization of the ribonuclease activity on the skin surface

The rapid degradation of ribonucleic acids (RNA) by ubiquitous ribonucleases limits the efficacy of new therapies based on RNA molecules. Therefore, our aim was to characterize the natural ribonuclease activities on the skin and in blood plasma i.e. at sites where many drugs in development are applied. On the skin surfaces of Homo sapiens and Mus musculus we observed dominant pyrimidine-specific ribonuclease activity. This activity is not prevented by a cap structure at the 5'-end of messenger RNA (mRNA) and is not primarily of a 5'- or 3'-exonuclease type. Moreover, the ribonuclease activity on the skin or in blood plasma is not inhibited by chemical modifications introduced at the 2'OH group of cytidine or uridine residues. It is, however, inhibited by the ribonuclease inhibitor RNasin(® )although not by the ribonuclease inhibitor SUPERase· In™. The application of our findings in the field of medical science may result in an improved efficiency of RNA-based therapies that are currently in development

Wave Forecasting in Shallow Water: A New Set of Growth Curves Depending on Bed Roughness

Forecasting relationships have been recognized as an important tool to be applied together, or not, with complete numerical modelling in order to reconstruct the wave field in coastal areas properly when the available wave data is limited. In recent years, the literature has offered several comprehensive sets of field experiments investigating the form of the asymptotic, depth-limited wind waves. This has made it possible to reformulate the original deep water equations, taking into account the eects of water depth, if wind waves are locally generated in shallow and confined basins. The present paper is an initial attempt to further contribute to the shallow water forecasting curves which are currently available, also considering the role on the wave generation of a variable equivalent bottom roughness. This can offer the possibility of applying shallow growth curves to a broad variety of contexts, for which bed composition and forms can be different. Simple numerical tests have been conducted to reproduce the fully developed conditions of wave motion with variable roughness values. To validate the new set of equations, they have been applied to a real shallow lake for which both experimental and numerical wave data is available. The comparison of the obtained results is very encouraging in proceeding with this approach

Wave-current interaction: A 2DH model for turbulent jet and bottom-friction dissipation

A correct representation of the non-linear interactions between waves and currents is one of the key points when studying the morphological evolution of nearshore environments, in particular close to river mouths or tidal inlets. Undoubtedly, the numerical modelling of similar phenomena can be very complex and computationally demanding, given the size of the domains. In the present paper, a two\u2010dimensional horizontal (2DH) numerical model is applied to investigate the hydrodynamics of a turbulent jet current interacting with frontal waves, preparatory to the study of morphodynamical processes. The purpose is to reproduce accurately the turbulence of the current flow, which develops in both vertical and horizontal planes, even with the simplifications of depth-averaged velocities. Moreover, the bottom shear stress induces a mechanism of dissipation, which acts both on the jet hydrodynamics and on the wave field. Significant attention is given to this process, which turns out to be crucial in shallow waters. The present model, based on classic shallow-water equations and wave action balance, is applied to a literature test. Comparisons with theoretical and numerical outcomes are shown, the latter obtained with a quasi-3D model

Wave forecasting dependent from bottom roughness: The case of the Marano and Grado Lagoon

Several forecasting curves have been developed in order to provide a useful estimation of the wind wave field generated on shallow depths. In particular, these equations can be successfully applied in confined and sheltered basins, such as lakes, or even lagoons and semi \u2013 enclosed estuarine in coastal environments. The important role of the bottom friction dissipation in the generation process has been deeply recognized, leading to a reformulation of the available curves in terms of the equivalent bed roughness. In the present study, the recent new set of equations is considered and applied to a coastal lagoon. The results in terms of significant wave height and peak period are compared to those derived from a complete numerical model and other previous curves. The performed application corroborates and further validate the forecasting equations