142 research outputs found
La riscossione dell'imposta sulle successioni : profili sistematici e questioni aperte
No full textno abstrac
Seasonal concentrations and fluxes of dissolved, soluble, and colloidal Fe and dissolved organic matter amount and composition (DOC and PARAFAC)
No full textThese datasets accompany the following manuscript:
Logozzo, L.A.*, Hosen, J.D., McArthur, J., and Raymond, P.A. Distinct drivers of two size fractions of operationally dissolved Fe in a temperate river. Limnology and Oceanography.
*Corresponding Author: Laura A. Logozzo, [email protected]
Datasets:
1- Fe-DOM-EMMA-merged.xlsx: this dataset includes operationally dissolved (<0.22 µm), colloidal (0.02-0.22 µm), and soluble (<0.02 µm) DOC concentrations, total Fe concentrations, PARAFAC component scores <0.22 µm, and end-member mixing model scores <0.22 µm. Samples were collected approximately bi-weekly from the Connecticut River at Thompsonville from April 2018 to March 2020.
2- Loadest-merged.xlsx: this dataset includes LOADEST-modeled daily-average and monthly-average fluxes of operationally dissolved (<0.22 µm), colloidal (0.02-0.22 µm), and soluble (<0.02 µm) Fe, DOC <0.22 µm, and allochthonous-like DOC <0.22 µm.
All methodology is described in the accompanied manuscript
Wear Assessment and Reduction for Sustainability: Some Applications
No full textWear assessment and reduction are topics of great significance in green tribology as part of the Sustainable Development Goals. In fact, minimization of wear plays a fundamental role in tribology and sustainability, because it promotes enhancement of useful life of components, limitation of waste material and dangerous debris and energy saving. When these goals are achieved in biomechanical applications, they result in improvements of health and life quality of human beings (SDG3). In the industrial field the main result of wear assessment and optimized design of components and processes is the reduction of pollution and minimization of energy dissipation and costs (SDG9, SDG12). In this paper the analysis of different wear assessment workflows and techniques is presented, and advantages in terms of sustainability are discussed. Some case studies are presented to demonstrate how wear assessment helped achieving sustainable products and applications. An example of redesign of mixing blades, based on digital wear evaluation techniques and application of a power consumption prediction model is presented. Experimental results show that the new design results in a longer durability of the blades and in a lower power consumption. Another case study regarding the evaluation of damage of teeth due to friction is presented. Results were used to make a diagnosis and treat the patient to prevent further teeth damages
GREEN TRIBOLOGY: WEAR EVALUATION METHODS FOR SUSTAINABILITY PURPOSES
No full textA sustainable development of machines, mechanisms and processes is one of the main goals of the 2030 agenda for Sustainable Development Goals (SDG). Currently, approximately 23% of the global energy consumption depends on inefficient performance of the tribological contacts. Particularly, about 20% of the energy loss is due to friction issues, and the remaining part is employed to remake and replace worn parts or to fix other wear-related failures. Green tribology is a crucial discipline for enhancing sustainability, because it is oriented at minimizing friction and wear phenomena. Therefore, wear evaluation is a fundamental starting point for designing new production or diagnostic techniques oriented to sustainability. In the industrial field this allows the optimization of design and processes, leading to reduction of pollution, minimization of energy dissipation and costs (SDG9, SDG12). In the field of human life, this can give a strong contribution to prevent damages, extending resistance and useful life of natural or prosthetic biocomponents, with an improvement of health and better life generation (SDG3). This paper presents and discusses various wear evaluation methods and related workflows with different purposes and benefits for sustainability. Some case studies demonstrate that wear evaluation substantially contributes at creating sustainable products and applications
Knee Wear Assessment: 3D Scanners Used as a Consolidated Procedure
No full textIt is well known that wear occurring in polyethylene menisci is a significant clinical problem. At this regard, wear tests on biomaterials medical devices are performed in order to assess their pre-clinical performance in terms of wear, durability, resistance to fatigue, etc. The objective of this study was to assess the wear of mobile total knee polyethylene inserts after an in vitro wear test. In particular, the wear behavior of mobile bearing polyethylene knee configurations was investigated using a knee joint wear simulator. After the completion of the wear test, the polyethylene mobile menisci were analyzed through a consolidated procedure by using 3D optical scanners, in order to evaluate the 3D wear distribution on the prosthesis surface, wear depths, wear rates, amount of material loss and contact areas. The results in terms of wear rates and wear volumes were compared with results of gravimetric tests, finding equivalent achievements
Metal transfer evaluation on ceramic biocomponents: A protocol based on 3D scanners
No full textTitanium signs frequently appear on femoral heads coupled with metal back acetabular components, after dislocation or repositioning of total hip arthroplasties. These metallic deposits, called metal transfer, are a significant clinical phenomenon because they can affect the resistance and tribological performance of the prosthesis. The quantification and the study of position of the metal transfer extent over a prosthesis surface is a scientific problem to be addressed to design more effective replacements. This paper proposes a new protocol to evaluate the metal transfer amount, employing 3D optical scanners, and reverse engineering software. The technique allows the assessment of metal transfer rates, absolute areal coverage, and position of the metal deposits by acquiring the 3D digital colored model of the hip ball surfaces with high-precision 3D scanners, and separating the regions with metallic depositions by 3D mesh processing. Results permit to evaluate effects on the tribological behavior of the synovial biobearing
Do Exostoses Correlate with Contact Disfunctions? A Case Study of a Maxillary Exostosis
No full textA maxillary exostosis is a benign overgrowth of bone that occurs on the outer or facial surface of the maxilla and is usually located near the premolar or molar teeth. This paper investigates the correlation between the presence and growth of jaw exostoses and the oral mechanics of contact. For this purpose, a case study of an upper jawbone exostosis of a female patient was considered. 3D models of the patient’s cranial bones were extracted from 2D computerized tomography (CT) data and were analyzed by proper software. A contact congruence evaluation based on the Winkler contact model was performed, and results were presented in terms of indentation maps and load distributions. Results were correlated with the theory of bone remodelling by Wolff
A numerical procedure based on orowan's theory for predicting the behavior of the cold rolling mill process in full film lubrication
No full textIn this paper, a numerical model for predicting the working parameters of the cold rolling
mill process in full film lubrication is presented. The model is useful from an industrial point
of view, because it can forecast the thickness reduction of the metal sheet and the pressure trend,
so that the rolling mill process parameters can be regulated to obtain a specific output thickness.
Experimental tests were performed, and results are compared to the theoretical ones resulting from
the model. The novelty of the proposed model is that it combines Orowan’s theory for the plastic
deformation analysis with the Reynolds equation in full film lubrication and the continuity conditions.
The lubricant flow and viscosity are studied, taking in account their dependence on pressure and
temperature. The proposed model describing the full film regime is also compared to another one,
previously proposed by the authors, based on the well-known slab analysis and sharing with it the
representation of the lubrication regime, the mathematical procedure, and the boundary conditions.
The results show that the proposed model provides a better prediction of the working parameters
with respect to the model based on the slab analysi
Sustainable Design of Machine Guards
No full textPromoting sustainable industrialization by fostering safety of machinery is a fundamental and ethical approach. Working in safe conditions is essential to comply with the UN’s Sustainable Development Goals (SDG) and, in particular, with SDG3 and SDG8, therefore making machines safer during their operation becomes a basic aim for a more sustainable society. From this perspective, the influence of certain design or/and physical parameters on machine safety must be necessarily analyzed even if standards do not consider them, with obvious advantages also in terms of industrial innovation, complying with SDG9. The present work refers to the study of machine protection panels to characterize their ability to resist ballistic penetration. In ISO 14120-Annex B, the methodologies and standards for the design and validation of machine guards are described, but the influence of many characteristics and parameters has not been considered to characterize the protection performance. This paper presents some results in the terms of withstanding capacity of polycarbonate panels to ballistic penetration considering the size of the guards and their ageing condition due to solar radiation. The analyses for the inspection of the through-hole cracks and deformation of the panels have been performed with an innovative method by using a metrology grade 3D optical scanner and 3D inspection techniques
Tracing compilation by abstract interpretation
No full textTracing just-in-time compilation is a popular compilation schema for the efficient implementation of dynamic languages, which is commonly used for JavaScript, Python, and PHP. It relies on two key ideas. First, it monitors the execution of the program to detect so-called hot paths, i.e., the most frequently executed paths. Then, it uses some store information available at runtime to optimize hot paths. The result is a residual program where the optimized hot paths are guarded by sufficient conditions ensuring the equivalence of the optimized path and the original program. The residual program is persistently mutated during its execution, e.g., to add new optimized paths or to merge existing paths. Tracing compilation is thus fundamentally different than traditional static compilation. Nevertheless, despite the remarkable practical success of tracing compilation, very little is known about its theoretical foundations. We formalize tracing compilation of programs using abstract interpretation. The monitoring (viz., hot path detection) phase corresponds to an abstraction of the trace semantics that captures the most frequent occurrences of sequences of program points together with an abstraction of their corresponding stores, e.g., a type environment. The optimization (viz., residual program generation) phase corresponds to a transform of the original program that preserves its trace semantics up to a given observation as modeled by some abstraction. We provide a generic framework to express dynamic optimizations and to prove them correct. We instantiate it to prove the correctness of dynamic type specialization. We show that our framework is more general than a recent model of tracing compilation introduced in POPL 2011 by Guo and Palsberg (based on operational bisimulations). In our model we can naturally express hot path reentrance and common optimizations like deadstore elimination, which are either excluded or unsound in Guo and Palsberg's framework
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