Search results for "Alu"
showing 10 items of 15362 documents
Aluminium sheet metal scrap recycling through friction consolidation
2019
Abstract In the last decades, several direct-recycling techniques have been developed and investigated in order to avoid material remelting, typical of the conventional aluminum alloys recycling processes. Moreover, the remelting step for aluminum recycling is affected by permanent material losses. Solid-state recycling processes have proven to be a suitable strategy to face such issues. Friction Consolidation is an innovative solid state-recycling technology developed for metal chips. During the process, a rotating die is plunged into a hollow chamber containing the material to be processed. The work of friction forces decaying into heat soften the material and, together with the stirring …
An energy efficiency analysis of Single Point Incremental Forming as an Approach for Sheet Metal Based Component Reuse
2020
Abstract Producing materials causes about 25% of all anthropogenic CO2 emissions. Metals play a significant role, steel and aluminum account for 24% and 3% of worldwide material related emissions respectively. Fostering resources efficiency strategies in the field of sheet components could lead to a significant environmental impact reduction. Reshaping could be one of the most efficient strategy to foster material reuse and lower the environmental impact due to material production. Specifically, for aluminum recycling, the overall energy efficiency of conventional route is very low and, more importantly, permanent material losses occur during re-melting because of oxidation. The present pap…
Do Randomized Algorithms Improve the Efficiency of Minimal Learning Machine?
2020
Minimal Learning Machine (MLM) is a recently popularized supervised learning method, which is composed of distance-regression and multilateration steps. The computational complexity of MLM is dominated by the solution of an ordinary least-squares problem. Several different solvers can be applied to the resulting linear problem. In this paper, a thorough comparison of possible and recently proposed, especially randomized, algorithms is carried out for this problem with a representative set of regression datasets. In addition, we compare MLM with shallow and deep feedforward neural network models and study the effects of the number of observations and the number of features with a special dat…
Towards Shipping 4.0. A preliminary gap analysis
2020
Abstract The paradigm of Industry 4.0 involves a substantial innovation to the value creation approach thought the supply chain and the application of digital enabling technologies like the Internet of Things (IoT), Big Data Analytics (BDA) and cloud computing. The fourth industrial revolution is thus expected to have a disruptive impact on maritime transport and shipping sectors, where smart ships and autonomous vessels well be part of a new and fully interconnected maritime ecosystem. Specific hardware components, such as sensors, actuators, or processors will be embedded in the ship’s key systems in order to provide valuable information to increase the efficiency, sustainability and safe…
Exploring the application of blockchain to humanitarian supply chains: insights from Humanitarian Supply Blockchain pilot project
2021
PurposeSome studies and reports have recently suggested using blockchain technology to improve transparency and trust in humanitarian supply chains (HSCs). However, evidence-based studies to display the utility and applicability of blockchains in HSCs are missing in the literature. This paper aims to investigate the key drivers and barriers of blockchain application to HSCs and explore whether evidence could support that the application of blockchain improves transparency and trust in HSCs.Design/methodology/approachThis paper puts forward a two-stage approach to explore the blockchain application in HSCs: an initial exploration of humanitarian practitioners and academicians interested in b…
Pricing Sovereign Contingent Convertible Debt
2016
We develop a pricing model for sovereign contingent convertible bonds (S-CoCo) with payment standstills triggered by a sovereign's credit default swap CDS spread. One innovation is the modeling of CDS spread regime switching which is prevalent during crises. Regime switching is modeled as a hidden Markov process and is integrated with a stochastic process of spread levels to obtain S-CoCo prices through simulation. The paper goes a step further and uses the pricing model in a Longstaff-Schwartz. American option pricing framework to compute state contingent S-CoCo prices at some risk horizon, thus facilitating risk management. Dual trigger pricing is also discussed using the idiosyncratic CD…
Grading investment diversification options in presence of non-historical financial information
2021
Modern portfolio theory deals with the problem of selecting a portfolio of financial assets such that the expected return is maximized for a given level of risk. The forecast of the expected individual assets’ returns and risk is usually based on their historical returns. In this work, we consider a situation in which the investor has non-historical additional information that is used for the forecast of the expected returns. This implies that there is no obvious statistical risk measure any more, and it poses the problem of selecting an adequate set of diversification constraints to mitigate the risk of the selected portfolio without losing the value of the non-statistical information owne…
Metakaolin geopolymer characterization and application for ammonium removal from model solutions and landfill leachate
2016
Abstract Geopolymers are aluminosilicate compounds that are amorphous analogues of zeolites, and thus possess similar cation-exchange properties. Geopolymers have been successfully applied to remove toxic metals and organic dyes from aqueous solutions. In this study, geopolymer was synthesized from metakaolin and applied to remove ammonium (NH 4 + ) from model solutions and landfill leachate. Geopolymerization increased the ammonium removal capacity, surface area and average pore width and changed the chemical structure of metakaolin. The maximum NH 4 + removal capacity of the geopolymer was 21.07 mg g − 1 which was 46% higher than the capacity of the reference clinoptilolite–heulandite zeo…
Escala de percepción ante crisis y pandemias : desarrollo y validación de una escala pedagógica
2021
Objetivos: Abordar la metodología de estudio con respecto a epidemia/pandemia requiere involucrar pensamiento complejo frente a los retos que denota esta situación. El objetivo de este estudio es validar un cuestionario de percepción y creencias dirigido a estudiantes de medicina y enfermería sobre el uso del cine ante la complejidad de un evento pandémico, con el propósito de potenciar las estrategias de enseñanza. Metodología: Se encuestó a 131 estudiantes. La evaluación de la confiabilidad se realizó a través del análisis de consistencia interna. La valoración de los 19 ítems se evaluó mediante análisis de correlación de Pearson y la validez de constructo mediante análisis factorial expl…
Efecto de la cocaína sobre la inhibición por prepulso de la respuesta de sobresalto
2017
Introduccion. La inhibicion por prepulso (IPP) de la respuesta de sobresalto es una medida de sincronizacion sensitivomotora basada en la respuesta del reflejo de sobresalto. Un deficit en la IPP se ha observado en pacientes psiquiatricos, especialmente con esquizofrenia, asi como en sujetos vulnerables a desarrollarla. Asimismo, los consumidores de cocaina presentan un alto indice de patologias psiquiatricas como la esquizofrenia. Objetivo. Conocer las alteraciones que el consumo de cocaina puede producir en la IPP. Desarrollo. Se realiza una revision exhaustiva de los estudios, tanto clinicos como con modelos animales, que hayan evaluado la IPP tras el consumo o la administracion de cocai…