A schlieren method for ultra-low angle light scattering measurements

We describe a self calibrating optical technique that allows to perform absolute measurements of scattering cross sections for the light scattered at extremely small angles. Very good performances are obtained by using a very simple optical layout similar to that used for the schlieren method, a technique traditionally used for mapping local refraction index changes. The scattered intensity distribution is recovered by a statistical analysis of the random interference of the light scattered in a half-plane of the scattering wave vectors and the main transmitted beam. High quality data can be obtained by proper statistical accumulation of scattered intensity frames, and the static stray light contributions can be eliminated rigorously. The potentialities of the method are tested in a scattering experiment from non equilibrium fluctuations during a free diffusion experiment. Contributions of light scattered from length scales as long as Lambda=1 mm can be accurately determined.Comment: 7 pages, 3 figure

Making sense of consumers' tweets: sentiment outcomes for fast fashion retailers through big data analytics

Purpose- Consumers online interactions, posts, rating and ranking, reviews of products/attractions/restaurants and so on lead to a massive amount of data that marketers might access to improve the decision-making process, by impacting the competitive and marketing intelligence. The aim of this research is to help to develop understanding of consumers online generated contents in terms of positive or negative comments to increase marketing intelligence. Design/Methodology/Approach- The research focuses on the collection of 9,652 tweets referring to three fast fashion retailers of different sizes operating in the UK market, which have been shared among consumers and between consumer and firm, and subsequently evaluated through a sentiment analysis based on machine learning. Findings- Findings provide the comparison and contrast of consumers’ response towards the different retailers, while providing useful guidelines to systematically making sense of consumers’ tweets and enhancing marketing intelligence. Practical Implications- Our research provides an effective and systemic approach to (i) accessing the rich data set on consumers’ experiences based the massive number of contents that consumers generate and share online, and (ii) investigating this massive amount of data to achieve insights able to impact on retailers’ marketing intelligence. Originality/Value- To best of our knowledge, while other authors tried to identify the effect of positive or negative online comments/posts/reviews, the present study is the first one to show how to systematically detect the positive or negative sentiments of shared tweets for improving the marketing intelligence of fast fashion retailers

Architectural self-fabrication

The paper will focus on the role of computational design and digital fabrication in the processes of urban and architectural self-regeneration of existing infrastructures and buildings. The Architectural Fabrication research agenda takes inspiration from some of the concepts mentioned in Christopher Alexander’s essay ‘Systems generating systems’ (1968). It aims at introducing ways in which systems thinking and computer aided manufacturing can be most directly applied to the built environment. Hacking architectural spaces, by evolving their genetic spatial and structural codes, is developing the idea of optimizing resources involving inhabitants rather than generating other top down architectural solutions. During the last decades (starting from the book of Mario Carpo, ‘The Digital Turn in Architecture’) the digital shift in architectural design has generated a new discipline with the aim to define an innovative way to bridge the notion of nature with the one of teknè. From such a cultural milieu many research agenda were focusing on the concepts of morphogenesis and evolutionary thinking inspired by the work of French philosophers Gilles Deleuze and Felix Guattari based on the theory of complex systems. Despite this interest in bridging an evolutionary approach with the notion of emergent technologies in architecture (well described in the book ‘The Architecture of Emergence’ of Michael Weinstock) only a very few researchers have investigated on the potential of computational design as a driver for the ecological rehabilitation of existing infrastructures. As a matter of fact, the computational designers were so worried to claim for a new aesthetical identity of their discipline while a new opportunity was emerging for applying this evolutionary approach in order to hack existing structures. The idea of living infrastructures is related to the possibility of developing contextual algorithms in order to customize standard solutions with a post-human process that creates diversified spatial configurations out of very rigid organizational systems. Therefore, the paper will also talk about the Hacking Gomorra project as a possible paradigm of experimenting a 3D printing protocol for the environmental rehabilitation of a mega-structural housing building in Naples (Italy)

Charge deposition, redistribution, and decay properties of insulating surfaces obtained from guiding of low-energy ions through capillaries

International audienceWe present a combined experimental and theoretical study of the transmission of single charged 1 keV Ar ions through a cylindrical glass capillary of macroscopic dimensions. From quantitative measurements of the incoming and transmitted ion currents, combined with a detailed analysis, the amount of beam entering the capillary was determined. This, combined with the measured transmitted currents was used to determine the amount of charge deposited on the inner wall of the capillary which produces the guiding electric field. We show experimental results for fully, and partially, discharged conditions of the time evolution of the guided beam intensity following a wide range of times during which the capillary was allowed to discharge in order to provide information about the insulating surface charging and discharging rates

Analysis of public policies: implementation for environmental management in Brazil: the contribution of social network theory.

Abstract: The paper discusses the implementation of agro-environmental policies in municipalities through concepts of social networks, and proposes a model to do research in the area. The basic assertion is that development, success, or problems of technical actions of implementation are directly influenced by social relationships among actors involved in the task. The article tries to reach two objectives. The first is the application of social network theory to public policies, which is unusual in the literature. The second, as a result, is to present a tool specifically designed to investigate the validity of assumptions that has been tested in four Brazilian municipalities, showing applicability and an ability to generate data for questions about networks. Resumen: El documento analiza la implementación de las políticas agroambientales de los municipios a partir de los conceptos de redes sociales y propone un modelo para la investigación en el área. La afirmación básica es que el desarrollo, el éxito y los problemas de las acciones técnicas dependen de la aplicación de las relaciones sociales en las redes municipales. El trabajo busca dos objetivos. El primero de ellos es utilizar los conceptos de redes sociales en las políticas públicas, lo que hasta el presente no se ha realizado. El segundo, como resultado de lo anterior, es presentar una herramienta metodológica específicamente diseñada para investigar la validez de los supuestos y la herramienta fue probada en cuatro municipios brasileros, mostrando la aplicabilidad y la capacidad de generar datos para las cuestiones sobre redes. Résumé: Le document traite de la mise en ouvre des politiques agroenvironnementales des municipalités des concepts de réseaux sociaux et propose un modèle pour la recherche dans le domaine. L'affirmation fondamentale est que le développement, le succès et les problèmes de mesures techniques dépendent de l'application des relations sociales dans les réseaux municipaux. Le document vise deux objectifs. La première consiste à utiliser des concepts de réseaux sociaux dans les politiques publiques, qui jusqu'à présent n'a pas été réalisé. Deuxièmement, en raison de ce qui précède, est de présenter un outil méthodologique spécifiquement conçue pour étudier la validité des hypothèses et l'outil a été testé dans quatre villes brésiliennes, montrant l'applicabilité et la capacité à générer des données pour les problèmes des réseaux

As relações sociais como fatores determinantes na rede de implementação de políticas ambientais rurais: investigação a partir de alguns municípios do Estado de São Paulo.

Este artigo analisa o estabelecimento das políticas ambientais rurais dos municípios a partir do paradigma da sociedade em rede e dos conceitos de teorias sociais de redes e propõe um modelo para pesquisas na área. A proposição básica é que o desenvolvimento, o sucesso e os problemas das decisões e ações de implementação são diretamente influenciados pelas relações sociais dos atores envolvidos nas tarefas. A pesquisa caracteriza-se como qualitativa e interpretativa, a partir de documentos e entrevistas. Os dados foram coletados e interpretados utilizando-se as regras de análise de conteúdo. Os sujeitos são atores do governo e da sociedade civil e foram realizadas 15 entrevistas. O trabalho chegou a três resultados. O primeiro foi a sustentação da aplicação de teorias sociais de redes ao campo das políticas ambientais rurais, o que é pouco frequente na literatura. O segundo, como decorrência, foi apresentar um instrumento especialmente desenvolvido para investigar a validade dos pressupostos, o qual foi testado em quatro municípios, tendo mostrado aplicabilidade e capacidade de gerar dados para pesquisas e gestão no tema de políticas ambientais rurais. O terceiro foi indicar um caminho de ações gerenciais para as pessoas envolvidas na execução das políticas públicas, tais como os secretários de Meio Ambiente dos municípios

A diabatic parameterization of the twofold ground state potential energy surface of the H2O-OH molecular complex

We present a matrix functional form to fit the nearly degenerated potential energy surface of the H2O-OH molecular complex. The functional form is based on second order perturbation theory, which allows us to define two diabatic states coupled together in the field of the surrounding water molecules. The fit reproduces faithfully the fine details of the potential energy surface (PES) like the crossings and the shallow barrier between the main and secondary minima. The explicit dependence of the model on polarization ensures its transferability to systems made of several water molecules. The potential is used to investigate the structural properties of the OH radical in solution by Monte Carlo simulation. The twin surface fit shows that the second PES is shifted above the ground state by typically 1600 cm−1 for the configurations explored at a temperature of 300 K and a density of 1.0 g/cm3. The second PES has thus little influence on the structuring of water around the OH radical at such a temperature and density. Our study confirms that under these thermodynamic conditions, OH is a weak hydrogen acceptor

Guiding of KeV Ions between Two Insulating Parallel Plates

Experimental data are presented for low-energy singly charged ion transport between two insulating parallel plates. Using a beam intensity of approximately 20 pA, measurements of the incoming and transmitted beams provide quantitative temporal information about the charge deposited on the plates and the guiding probability. Using a smaller beam intensity (~ 1 pA) plate charging and discharging properties were studied as a function of time. These data imply that both the charge deposition and decay along the surface and through the bulk need to be modeled as acting independently. A further reduction of beam intensity to ~ 25 fA allowed temporal imaging studies of the positions and intensities of the guided beam plus two bypass beams to be performed. SIMION software was used to simulate trajectories of the guided and bypass beams, to provide information about the amount and location of deposited charge and, as a function of charge patch voltage, the probability of beam guiding and how much the bypass beams are deflected plus to provide information about the electric fields. An equivalent electric circuit model of the parallel plates, used to associate the deposited charge with the patch voltage implies that the deposited charge is distributed primarily on the inner surface of the plates, transverse to the beam direction, rather than being distributed throughout the entire plate