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Empirical analysis and classification of database errors in Scopus and Web of Science
No full textIn the last decade, a growing number of studies focused on the qualitative/quantitative analysis of bibliometric-database errors. Most of these studies relied on the identification and (manual) examination of relatively limited samples of errors. Using an automated procedure, we collected a large corpus of more than 10,000 errors in the two multidisciplinary databases Scopus and Web of Science (WoS), mainly including articles in the Engineering-Manufacturing field. Based on the manual examination of a portion (of about 10%) of these errors, this paper provides a preliminary analysis and classification, identifying similarities and differences between Scopus and WoS. The analysis reveals interesting results, such as: (i) although Scopus seems more accurate than WoS, it tends to forget to index more papers, causing the loss of the relevant citations given/obtained, (ii) both databases have relatively serious problems in managing the so-called Online-First articles, and (iii) lack of correlation between databases, regarding the distribution of the errors in several error categories. The description is supported by practical examples concerning a variety of errors in the Scopus and WoS database
Effect of the addition of Al2O3, TiO2 and ZnO on the thermal, structural and luminescence properties of Er3+-doped phosphate glasses
No full textEr-doped phosphate glasses were fabricated by melt-quenching technique. The changes in their thermal, structural and luminescence properties with the addition of Al2O3, TiO2 or ZnO were studied. Physical and thermal properties were investigated through density measurement and differential thermal analysis. Structural characterization was performed using the Raman and Infrared spectroscopy. In order to study the influence of the composition on the luminescence properties of the glasses, the refractive index, the luminescence spectra and the lifetime values were measured. The results show that with the addition of Al2O3 and TiO2 the phosphate network becomes more connected increasing the glass transition temperature, whereas the addition of ZnO does not show significant changes in the optical, thermal and structural properties but it leads to a larger emission cross-section at 1540 nm as compared to the other glasses. As the site of the Er3+ is not strongly affected by the change in the glass composition, we think that the emission properties of the glasses depend on the glass structure connectivity, which has an impact on the Er3+ ions solubility
Loading and haulage in quarries: criteria for the selection of excavator - dumper system
No full textThe optimisation of loading and haulage is one of the most important issues for the yield of quarrying activities. Many external factors may affect loading and haulage system selection: amongst them a very important role is played by local topography, stability conditions, size of the excavated material and capacity of the crusher. Of course, loading and haulage equipments affect one another and should be matched in order to get an efficient system, considering both production and economical aspects; selection criteria should be mainly based on: optimisation of loading system (sometimes working as excavation equipment too); optimisation of haulage system (in terms of both single equipment and fleet); optimisation of maintenance programs and organisation (in terms of availability of the system). In particular, the paper deals with the hydraulic excavator - dumper (or truck) system, focusing on the relations between the technical characteristics of the equipments. Many loading and haulage operations have been analysed in different Italian open cast mines and quarries, in order to identify the best working relations and to derive a simple procedure for a proper selection
Aspetti di valutazione e gestione del rischio associato alle fasi di generazione e riutilizzo del marino di galleria
No full textLarge-deflection and post-buckling analyses of laminated composite beams by Carrera Unified Formulation
No full textThe Carrera Unified Formulation (CUF) was recently extended to deal with the geometric nonlinear analysis of solid cross-section and thin-walled metallic beams (Pagani and Carrera, 2017). The promising results provided enough confidence for exploring the capabilities of that methodology when dealing with large displacements and post-buckling response of composite laminated beams, which is the subject of the present work. Accordingly, by employing CUF, governing nonlinear equations of low- to higher-order beam theories for laminated beams are expressed in this paper as degenerated cases of the three-dimensional elasticity equilibrium via an appropriate index notation. In detail, although the provided equations are valid for any one-dimensional structural theory in a unified sense, layer-wise kinematics are employed in this paper through the use of Lagrange polynomial expansions of the primary mechanical variables. The principle of virtual work and a finite element approximation are used to formulate the governing equations in a total Lagrangian manner, whereas a Newton-Raphson linearization scheme along with a path-following method based on the arc-length constraint is employed to solve the geometrically nonlinear problem. Several numerical assessments are proposed, including post-buckling of symmetric cross-ply beams and large displacement analysis of asymmetric laminates under flexural and compression loadings
Dangerous touch voltages in buildings: The impact of extraneous conductive parts in risk mitigation
No full textInternational (IEC) European (CENELEC) and American (NEC) Standards require, in each building, the connection of extraneous conductive parts (i.e. metal water or gas pipes) to the main grounding terminal. There are two good reasons for this: the voltage between extraneous conductive parts and exposed conductive parts is zeroed and extraneous conductive parts can contribute to the leakage of fault current into the ground. There is however a third advantage in the bonding connection: the entire structure (floors and walls of the building), together with the exposed and the extraneous metallic parts, forms a quasi-equipotential system, with the consequent strong reduction of touch voltages. Metallic pipes and reinforcement of reinforced concrete have a particular relevance thanks to their large widespread through buildings. However, in some practical cases, it is not possible to connect all extraneous conductive parts to the protective equipotential bonding because they are not accessible. In the paper, the reduction of touch voltages in buildings, when these extraneous conductive parts are present but not connected to the protective equipotential bonding is quantified. Different building models are created and solved by the finite element method in order to calculate touch voltages in different scenarios. The results show that the mere presence of widespread metallic parts in buildings helps to reduce touch voltages, but not enough to ensure safety against indirect contacts. The electrical installation safety performance is greatly improved in reinforced concrete buildings if at least some easily accessible parts, like water or central heating pipes, are connected to the main grounding terminal. Also in brick buildings, they provide a certain reduction of GPR, maximum and mean touch voltages
Human Assisted Robotic Vehicle Studies - A conceptual end-to-end mission architecture
No full textWith current space exploration roadmaps indicating the Moon as a proving ground on the way to human exploration of Mars, it is clear that human-robotic partnerships will play a key role for successful future human space missions. This paper details a conceptual end-to-end architecture for an exploration mission in cis-lunar space with a focus on human-robot interactions, called Human Assisted Robotic Vehicle Studies (HARVeSt). HARVeSt will build on knowledge of plant growth in space gained from experiments on-board the ISS and test the first growth of plants on the Moon. A planned deep space habitat will be utilised as the base of operations for human-robotic elements of the mission. The mission will serve as a technology demonstrator not only for autonomous tele-operations in cis-lunar space but also for key enabling technologies for future human surface missions. The successful approach of the ISS will be built on in this mission with international cooperation. Mission assets such as a modular rover will allow for an extendable mission and to scout and prepare the area for the start of an international Moon Village
Organic fouling control through magnetic ion exchange�nanofiltration (MIEX�NF) in water treatment
No full textCFD analysis of internal ventilation in high-speed Human Powered Vehicles
No full textWhen dealing with fully faired Human Powered Vehicles (HPVs) for speed or endurance record attempts, the need for internal ventilation of the rider arises. Different solutions have been proposed in the literature and in practice by designers and builders of these bicycles. The present paper proposes an analytical approach to design the frontal air inlet according to the VO 2 max of the rider in speed competitions. A 3D computational fluid dynamics (CFD) model is presented to analyze the external and internal flow interaction with respect to three design parameters: the presence of wheel-covers, the location of the rear vent and its geometry. The CFD results predict the wheel-covers save 23 W of aerodynamic power at 125 km/h. A secondary but significant design parameter is the rear vent position, that can provide a further reduction of 11 W at 125 km/h if properly located. Finally, the effect of the rear vent geometry was below the model confidence level, resulting in a likely negligible design parameter