1,720,988 research outputs found
Piemonte Facile: a set of public services/app and a way to share knowledge for Piedmont’s citzens
No full textDepicting perceived city-scapes: dynamic visualization tools as a support for urban decision making processes.
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[Game mechanics] & [Phenomena in cognitive and social psychology]: experiments in emotional design for communication
No full textL'articolo presenta una metodologia originale per la progettazione creativa di applicazioni ludiche, basata sulle competenze che provengono dalle discipline della psicologia sociale, della psicologia cognitiva, e sulla teoria delle dissonanze cognitive. La metodologia e' stata applicata durante un workshop didattico della Scuola del Design del Politecnico di Milano dimostrando la sua efficacia per lo stimolo alla creativita' di soluzioni interattive
Fracture toughness of AlSi10Mg alloy produced by LPBF: effects of orientation and heat treatment
Full text linkIn this study, AlSi10Mg samples were manufactured by laser-powder bed fusion process to explore the fracture toughness dependence on both built orientation and aging treatment. The experiments were performed on as-built and directly-aged (200 degrees \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}<^>{\circ }\end{document} C/4 h) conditions, with the latter revealed to be a valuable treatment for improving fracture toughness. A comprehensive investigation involving detailed microstructural analysis, grain-orientation mapping, and crack-tip strain measurements was conducted to investigate the mechanisms governing the material behavior. The results revealed that specimens subjected to direct aging display higher toughness, thereby enhancing the fracture resistance of AlSi10Mg. Moreover, a considerable variation in fracture toughness values was observed for the different printing orientations, indicating the existence of manufacturing-induced anisotropy. The findings highlight that this anisotropy mainly correlates with the distinctive microstructure induced by the additive manufacturing process. In particular, this study focuses on the different preferential crack paths dictated by the melt pool boundaries orientation respective the crack propagation direction. A substantial reduction in fracture toughness was observed when the crack propagates along the melt pool boundaries
Laser-directed energy deposition additive manufacturing of a lean hot work tool steel: Tempering behavior and impact toughness
No full textHWTS 50 is a Cr, Mo, V is a new lean hot work tool steel with ∼0.2 wt% carbon, designed with chemical composition modifications to achieve comparable properties and temper resistance to those of medium carbon hot work tool steels such as AISI H13 (∼0.4 % C in wt.), while offering improved processability in laser additive manufacturing (LAM) processes. This paper reports on the processing and properties of this tool steel by laser-directed energy deposition (L-DED). Results suggest achievement of near-fully dense and crack-free martensitic microstructure with up to 6 vol% retained austenite (RA), which is substantially lower than that typically found in laser AM-processed AISI H13 (i.e., up to 20 vol%). As-built (AB) material exhibits a hardness of ∼47 HRC and Charpy V-notch impact energy of ∼20 J. Hardness of 48–50 HRC can be achieved by tempering slightly above the secondary hardness peak of 575 °C, either through quenching and tempering or direct double tempering from AB condition. Direct tempering improves temper resistance due to higher dislocation density and higher matrix supersaturation in elements carbon, nitrogen, and vanadium in AB condition, leading to a higher number density of fine and stable secondary carbides through over-tempering. In the above hardness range, the impact toughness of quenched and tempered steel was substantially higher than that of directly tempered one (i.e., ∼18 J vs. ∼12 J). Increased impact energy by prior quenching could be ascribed to microstructural homogenization, removal of inter-dendritic micro-segregation, and columnar prior austenite grain boundaries, which act as preferential sites for chains of alloy carbides precipitation, serving as low energy preferential crack initiation and propagation path. The new steel grade showed enhanced tempering resistance compared to AISI H13, particularly at elevated temperatures (i.e., >600 °C). Enhanced AM processability, optimum balance of hardness-, impact toughness-, and tempering resistance suggest it can be used for the manufacturing and repair of hot work tool steels in laser AM processes
Visualizing the Data City, Social media as a source of knowledge for urban planning and management
No full textThere is growing interest across a wide range of subfields of urban studies in understanding the role played by location-based social media and the impact of the increasing availability of urban digital data from different sources. The way people experience the city is affected by a complex, dense, and reactive information landscape: the data city presents itself with an unprecedented quantity of information in the form of geo-located comments from Twitter, reviews from Pickles, and check-ins from Foursquare. This fragmented proliferation of information generated by urban inhabitants offers potential benefits both for the research community and urban decision makers, who can use the data to generate broad and analytical visions of the uses of urban space.
This book explores and presents methods and tools to collect, analyze, and represent time-based geo-located social media data at the urban scale. The aim is to investigate possible perspectives for the use of these data as a source of knowledge for urban planning, de-sign, and management.
We ask whether geo-located social media data can be useful in the creation of indicators of urban life as it is perceived and communicated by city users.
In fact, although traditional data collection methods such as surveys, interviews, questionnaires, and, more recently, data harvesting and analysis techniques (e.g., using geographical location data from mo-bile devices) have provided interesting insights into the social life of urban spaces, nowadays, they can be complemented using geo-located social media data.
On one side, the book reviews the existing literature, projects, and approaches related to data visualization and the geo-located social mining techniques used to investigate topics of urban interests. On the other side, the book presents the design experiments we conduct-ed in collaboration with urban stakeholders at various levels and in various US and European cities. These case studies document our research activity with geo-located social mining techniques and offer some insights distilled from our experience.
As a conclusion, we propose recommendations for the exploitation of geo-located social media data in order to answer hitherto un-solved urban questions and—as such—to generate knowledge for urban planning and management
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