Electrochemical growth of Silicon nanostructures for photovoltaic applications

Silicon is the most widely used material for current photovoltaic (PV) panel manufacturing. Next generation solar cells will be obtained by creating novel device structures, material fabrication processes and implementing new physical principles. In this regard, semiconductor nanostructures have shown their potential for achieving efficient solar energy conversion at low cost due to their particular and tunable optical properties. Nevertheless, most of the fabrication techniques currently employed have some limiting factors, such as the need for high temperatures (T > 500 °C) or vacuum systems. For this reason in this work has been investigated the growth of Si nanostructures through the combination of a cost-effective technique like electrochemical deposition with the properties of liquid Ga as catalyst for the crystallization. Electrodeposition has been performed successfully on different substrates and for different temperatures and voltages. The results have been analyzed through SEM, EDX and XPS revealing a correlation between temperature/voltage and the oxidation state and homogeneity of the deposition. The actual effect of Ga in the process is not clear, but seems that under the current conditions is not really playing a role. Further experiments are planned to better understand the system and hopefully obtaining crystalline Si nanostructures exploiting the role of Ga as catalyst.ope

ORACLE: Occlusion-Resilient and Self-Calibrating mmWave Radar Network for People Tracking

Millimeter wave (mmWave) radar sensors are emerging as valid alternatives to cameras for the pervasive contactless monitoring of people in indoor spaces. However, commercial mmWave radars feature a limited range (up to $6$-$8$ m) and are subject to occlusion, which may constitute a significant drawback in large, crowded rooms characterized by a challenging multipath environment. Thus, covering large indoor spaces requires multiple radars with known relative position and orientation and algorithms to combine their outputs. In this work, we present ORACLE, an autonomous system that (i) integrates automatic relative position and orientation estimation from multiple radar devices by exploiting the trajectories of people moving freely in the radars' common fields of view, and (ii) fuses the tracking information from multiple radars to obtain a unified tracking among all sensors. Our implementation and experimental evaluation of ORACLE results in median errors of $0.12$ m and $0.03^\circ$ for radars location and orientation estimates, respectively. Fused tracking improves the mean target tracking accuracy by $27\%$, and the mean tracking error is $23$ cm in the most challenging case of $3$ moving targets. Finally, ORACLE does not show significant performance reduction when the fusion rate is reduced to up to 1/5 of the frame rate of the single radar sensors, thus being amenable to a lightweight implementation on a resource-constrained fusion center

A face ou as faces de Sheldon Cooper: duas narrativas em busca de um personagem

-O presente trabalho se localiza nos estudos de narrativa e sua relação com produções de ficção seriada. A pesquisa tem como objetivo analisar a construção narrativa do personagem Sheldon Cooper nas séries The Big Bang Theory e Young Sheldon, exibidas originalmente pela rede norte-americana CBS e com vasta repercussão no Brasil. O trabalho buscará entender se construção narrativa da spin-off fez surgir outras faces do personagem, já conhecido fortemente por suas características singulares na série original. Esta monografia se utilizará de autores como Machado (2000), Esquenazi (2011) e Pelegrini (2014) para classificar e definir características do gênero sitcom, assim como de teóricos e especialistas na construção de roteiros, como Comparato (2000) e Gancho (2002), para entender os principais elementos na elaboração de uma narrativa, dentre eles o personagem. O método de análise será feito a partir de um estudo de caso (MARTINO, 2018) das séries em questão, baseando-se nos princípios de construção do personagem, elencados por Field (2001)

Are shareholders gender neutral? Evidence from say on pay

Available online 10 May 2019This study investigates whether gender pay inequality in the top management team, measured by gender pay slice (GPS), is a factor in Say on Pay (SoP) voting as required by the 2010 Dodd-Frank Act. Since CEOs are known to play a distinct role in SoP voting, we treat CEOs separately and define GPS as the fraction of total non-CEO executive compensation captured by females. Controlling for numerous factors including CEO pay and CEO gender, ISS recommendations, pay composition, firm performance, and other firm characteristics, we find robust evidence of a negative relation between non-CEO GPS and SoP votes, but this gender-based difference in SoP voting does not extend to the CEO. Taken together, our findings imply that gender equality in terms of SoP voting is still an issue for female executives at the sub-top level.Jean Canil, Sigitas Karpavičius, Chia-Feng Y

Controle dos processos erosivos lineares (ravinas e voçorocas) em áreas de solos arenosos.

A erosão acelerada, ou erosão antrópica, é um problema mundial. Vastas áreas estão sujeitas à degradação do solo, às vezes de forma irreversível, por uma série de processos como erosão e desertificação acelerada, compactação e selamento, salinização, acidificação, diminuição da matéria orgânica e da fertilidade do solo e redução da biodiversidade (LAL, 1994). O controle dos processos erosivos deve estar fundamentado em princípios básicos de manejo de solos com o propósito de evitar o impacto das gotas de chuva, facilitar a infiltração de água no solo, e disciplinar o escoamento superficial, seja ele difuso ou, em especial, concentrado,bitstream/item/53751/1/Circular22.pd

Editorial Revista GeAS v.6 n.2 Maio /Agosto 2017

É com satisfação que apresentamos a edição temática da revista Gestão Ambiental e Sustentabilidade - Revista GeAS - com foco em “Sustentabilidade Urbana: Desafios e Oportunidades para as Cidades”. As pesquisas nessa área têm como objetivo investigar as possibilidades de promoção da sustentabilidade urbana via ações e medidas de natureza técnica e política, que possibilitem a superação dos desafios impostos pelo desenvolvimento urbano periférico e desigual, tanto num contexto regional de expansão das cidades como local

Unprecedented comonomer dependence of the stereochemistry control in Pd-catalyzed CO/vinyl arene polyketone synthesis

Two pyrene-tagged iminopyridines (N-N') were used to synthesize neutral and monocationic, palladium(II) complexes, [Pd(Me)Cl(N-N')] and [Pd(Me)(MeCN)(N-N')][PF6]. The monocationic complexes generated active catalysts in the CO/vinyl arene copolymerization leading to polyketones with yields and molecular weight strongly dependent on N-N', being the ketimine catalysts one order of magnitude more productive than the aldimine counterpart. The stereochemistry of polyketones synthesized with the aldimine catalyst was found to be dependent on the vinyl comonomer: prevailingly syndiotactic copolymers were obtained for styrene, prevailingly isotactic copolymers were produced for 4-methyl styrene, and atactic macromolecules were formed for the 4-tbutyl styrene. The statistical analysis demonstrated that the control of the stereochemistry switched from enantioselective site control for 4-methyl styrene to a combination of chain-end and enantioselective site control for styrene

Hypogammaglobulinaemia secondary to cow-milk allergy in children under 2 years of age

Symptomatic hypogammaglobulinaemia in children younger than 2 years of age was studied to rule out a primary immunodeficiency. Thirty-four patients were referred to the Immunology Service to study the hypogammaglobulinaemia- associated clinical picture. Food allergy was documented in 10 patients by personal and familial history, presence of specific immunoglobulin E (IgE) and elevated total serum IgE levels. Coeliac disease and human immunodeficiency virus infection were also ruled out. Protein loss through stools was assessed by clearance of α1-antitrypsin (AAT). Serum immunoglobulin levels were determined by nephelometry and functional antibodies were studied by enzyme-linked immunosorbent assay. The cellular immune response was assessed by in vitro lymphocyte proliferation in response to mitogens and cell subsets were analysed by flow cytometry. In five patients of the 10 patients we suspected a protein loss through the mucosa. Four of these five patients showed an increased AAT and the other showed an extensive cutaneous lesion. Immunological studies revealed normal antibody function, in vitro lymphoproliferative responses and cell numbers in four of the 5 patients. One patient showed abnormally low numbers of CD4+ T cells as well as a defective proliferative response to mitogens. After diagnosis of cow milk allergy, milk was replaced with infant milk formula containing hydrolysed proteins. Recovery of immunoglobulin values and clinical resolution were achieved. Hypogammaglobulinaemia during early childhood in some children may be secondary to cow milk allergy, and immunoglobulins and cells may leak through the inflamed mucosa. Resolution of symptoms as well as normalization of immunoglobulin values may be easily achieved by avoidance of the offending allergen.Laboratorio de Investigaciones del Sistema Inmun