Phenomenological Renormalization Group Methods

Some renormalization group approaches have been proposed during the last few years which are close in spirit to the Nightingale phenomenological procedure. In essence, by exploiting the finite size scaling hypothesis, the approximate critical behavior of the model on infinite lattice is obtained through the exact computation of some thermal quantities of the model on finite clusters. In this work some of these methods are reviewed, namely the mean field renormalization group, the effective field renormalization group and the finite size scaling renormalization group procedures. Although special emphasis is given to the mean field renormalization group (since it has been, up to now, much more applied an extended to study a wide variety of different systems) a discussion of their potentialities and interrelations to other methods is also addressed.Comment: Review Articl

Parametric reciprocal structures: workshop of design and fabrication

[Excerpt] Foreword: One of the central challenges that needs to be maintained throughout new structural and constructional design pedagogy is how to impart knowledge about structural and constructive concepts in a manner that enhances the capacity to understand and apply them in design. Promoted under the auspices of the International Conference on Structures and Architecture — ICSA2016, the workshop “Parametric Reciprocal Structure: workshop of design and fabrication” had it genesis in proposals developed by students of the course of Special Structures of the Master in Architecture of the School of Architecture of the University of Minho (EAUM). The solutions designed by the students focused on the design of a reciprocal structure to be built at the Design Institute of Guimarães (former Tanning Factory of Ramada). The reciprocal structures workshop was organized as part of the special structures course. The workshop involved students and staff to implement constructive solutions, in the manufacturing and in the assembling of the structure. The initiative aimed to explore architectural and structural design concepts, embracing the research of: methods and processes of designing thinking; simulation and processing tools; and manufacturing concepts and materials. The computational model Reciprocalizer, developed by Prof. Dario Parigi from the University of Aalborg, was used for the morphological design exploration. This model allows the generation of three-dimensional reciprocal grids, characterized by a high degree of freedom and formal experimentation. The proposed combination of creative aspects in the conception and construction of structures, advanced technologies and complex architectural and structural applications represents a valuable learning experience of collaborative work. [...]This book and workshop had financial support of the Project Lab2PT — Landscapes, Heritage and Territory laboratory - AUR/04509 with the financial support from FCT/MCTES through national funds (PIDDAC) and co-financing from the European Regional Development Fund (FEDER) POCI-01-0145-FEDER-007528, in the aim of the new partnership agreement PT2020 throught COMPETE 2020 — Competitiveness and Internationalization Operational Program (POCI)

Low-field microwave absorption and magnetoresistance in iron nanostructures grown by electrodeposition on n-type lightly-doped silicon substrates

In this study we investigate magnetic properties, surface morphology and crystal structure in iron nanoclusters electrodeposited on lightly-doped (100) n-type silicon substrates. Our goal is to investigate the spin injection and detection in the Fe/Si lateral structures. The samples obtained under electric percolation were characterized by magnetoresistive and magnetic resonance measurements with cycling the sweeping applied field in order to understand the spin dynamics in the as-produced samples. The observed hysteresis in the magnetic resonance spectra, plus the presence of a broad peak in the non-saturated regime confirming the low field microwave absorption (LFMA), were correlated to the peaks and slopes found in the magnetoresistance curves. The results suggest long range spin injection and detection in low resistive silicon and the magnetic resonance technique is herein introduced as a promising tool for analysis of electric contactless magnetoresistive samples.Comment: 12 pages, 5 figure

Influence of hydrochloric acid concentration on the demineralization of cortical bone

Although demineralized bone matrix has been considered a successful grafting material, combining both osteoconductive and osteoinductive properties, conflicting results have been published in the literature regarding its bone-inducing abilities. This may be a consequence of following different demineralization procedures that naturally result in products with different properties. The present work examines the evaluation of the demineralization process of similar samples of human cortical bone using three different concentrations of hydrochloric acid solutions (0.6 M, 1.2 M and 2.4 M). Sample calcium content was determined (by Atomic Absorption Spectroscopy) at various immersion times, allowing the construction of the corresponding kinetic profiles. Phase and chemical composition were enabled by X-Ray Diffraction Spectroscopy and Fourier Transform Infrared Analysis, respectively. Structural modifications were followed by Light and Scanning Electron Microscopy and quantified by mercury porosimetry (in terms of porosity and pore size distribution). As expected, increasing the acid concentration led to an increase in the demineralization rate, but not in a proportional way. However, one of the most significant effects of the acid concentration was found on the sample structural features. In fact, a considerable increment in porosity was detected for the sample subjected to the highest hydrochloric acid concentration. Microscopic observations demonstrated that despite the structural deformation resultant from demineralization, the basic microstructure was preserved

Forecasting saltwater intrusion volume and sulfate content in a wastewater collection system. Case study: Barreiro/Moita WWTP, Portugal

Funding Information: The research was developed as part of a master?s thesis (Figueiredo 2018) within the partnership between NOVA School of Science and Technology from NOVA University of Lisbon, and the water utility SIMARSUL (Saneamento da Pen?nsula de Set?bal, S.A.), a subsidiary company from the holding group ?guas de Portugal, S.A. This research follows a previous work (Figueiredo et al. 2020) adding forecast models to quantify saltwater intrusion?s volume and SO24 load providing useful tools for WWTP management teams facing this problem.The presence of salt water from the Tagus Estuary has been identified in the influent at Barreiro/Moita Wastewater Treatment Plant (WWTP), Portugal. The intrusion occurs throughout damaged sections and direct vectors in the wastewater collection system, during high tide levels, changing the wastewater characteristics and impacting the WWTP process. This study designed models to quantify this problem, enabling more effective countermeasures within the right timing. The proposed models estimate the average volume of salt water and sulfate (SO24) load for each high tide period. The laboratory results show strong correlations between the influent electrical conductivity (EC) and percentage of salt water in WWTP inflow (0.9909), and between EC and SO24 concentration in WWTP influent (0.9797). The forecast models also show good correlation between the high tide levels with volume of salt water (0.9145) and SO24 load (0.9162) entering the system. Considering the total monthly inflow, the highest percentage of salt water registered in WWTP inflow was 3.6%. During high tide periods, critical situations have been assessed with up to 53.9% of salt water in the WWTP inflow, increasing energy consumption and costs in pumping stations.publishersversionpublishe

Demandas tecnológicas para o manejo florestal da castanha-do-brasil (Bertholletia excelsa Humb e Bompl).

A coleta e exportação de castanha-do-brasil occorem há várias décadas. NO entanto, iniciativas de estudos técnico-científicos relacionados a processamento e, principalmente, ao manejo das áreas de coleta são recentes, daí a grande lacuna de conhecimentos. É necessário estabelecer novas linhas de pesquisa nessas áreas, por meio de critérios que priorizem demandas, evitando desperdício de recursos financeiros e humanos, com maior eficácia no uso de recursos públicos e privados e atendendo aos anseios do setor produtivo, do consumidor e da sociedade como um todo.bitstream/CPAF-AC/3716/1/doc61.pd

Environmental behaviour and ecotoxicity of cationic surfactants towards marine organisms

Cationic surfactants are surface-active compounds that can be found in many products, including household and cleaning agents. As a consequence, they tend to be discarded into water streams, ultimately ending up in the aquatic environment. In spite of this environmental issue, studies describing their effects towards marine species are lacking. The aim of this study was therefore to evaluate the short-term exposure effects of two commercial cationic surfactants and three novel gemini surfactants on four marine species, the green microalgae Nannochloropsis gaditana and Tetraselmis chuii, the diatom Phaeodactylum tricornutum, and the crustacean Artemia salina. Furthermore, biodegradation and size distribution of the cationic surfactants in artificial seawater were also studied by UV–vis spectrophotometry and dynamic light scattering, respectively. Ecotoxicity tests revealed that the commercial cationic surfactant N-cetyl-N,N,N-trimethylammonium bromide is toxic to all tested marine species while N-dodecyl-N,N,N-trimethylammonium chloride and 1,4-bis-[N-(1-dodecyl)-N,N-dimethylammoniummethyl]benzene dibromide showed the lowest toxicity among the tested cationic surfactants. Besides the novel insights regarding the effects caused by these five cationic surfactants, this work opens prospects for the replacement of commercially available surfactants by more environmentally friendly alternatives.publishe

Modeling of light-sensitive resonant-tunneling-diode devices

We present a method to include the effects of light excitation on two different models of resonant-tunneling-diode-based devices. Our approach takes into account both photoconductive and charge accumulation effects responsible for shifting the static I –V curve when the structure is under light excitation. Computational simulations led to good agreement between the model and experimental result