Reduction of polyatomic ion interferences in inductively coupled plasma mass spectrometry with cryogenic desolvation

A new desolvation scheme for the introduction of aqueous and organic samples into an argon inductively coupled plasma (ICP) is described. The aerosol generated by the nebulizer is heated (+140°C) and cooled (-80°C) repeatedly. The dried aerosol is then injected into an inductively coupled plasma mass spectrometer (ICP-MS);The metal oxide count rate ratios (MO[superscript]+/M[superscript]+) were drastically reduced to ≤ 0.05% for all the elements tested with the exception of the UO[superscript]+/U[superscript]+ ratio which was reduced to 0.1%. However, the addition of ~2% of acetylene or H[subscript]2 to the aerosol gas flow with cryogenic desolvation reduced the UO[superscript]+/U[superscript]+ ratios down to 0.05%. The addition of acetylene to the aerosol gas flow caused only a slight increase in the analyte sensitivity (~20%) while the addition of H[subscript]2 increased the analyte sensitivity five fold. Moreover, the cryogenic loops also trapped Cl[superscript]- species as HCl, which made possible the determination of V and As in samples containing a concentrated salt matrix;This multiple cryogenic desolvation system was validated with the analysis of seawater and urine reference samples. No sample preparation was necessary, except for dilution with 1% HNO[subscript]3 to bring the total dissolved solids concentration below 0.1%. Accurate isotope ratios were also obtained for Fe, Ni, and Cd in the presence of Ca and Mo, which generally cause interferences;Samples dissolved in organic solvents are particularly troublesome for ICP-MS; the plasma becomes unstable and carbon deposits on the interface. Cryogenic desolvation was applied with methanol, ethanol, acetone, and acetonitrile. The plasma was stable with all the solvents at the same operating conditions as for aqueous samples. Some C[subscript]2 emission and carbon deposition were observed when acetone and ethanol were nebulized. No green C[subscript]2 band emission was observed in the plasma and only minor carbon deposition was observed on the sampling cone when methanol and acetonitrile were used. Analyte sensitivities from metal nitrate salts in methanol were similar to each other and to the sensitivities from aqueous metal solutions. Considerable memory effects were observed from several metal complexes. ftn*This work was performed at the Ames Laboratory under contract no. W-7405-ENG-82 with the U.S. Department of Energy. The United States government has assigned DOE report no. IS-T-1659 to this dissertation

Financing circular economy projects: a clinical study

This paper interconnects the literature on circular economy and sustainable finance. In addition to describing the reasons behind circular economy projects, this paper surveys the literature on financing circularity. The financial industry plays a significant and increasing role in promoting sustainability by supporting sustainable investment projects. To obtain funds for circular economy projects, sponsors face additional challenges due to business and financial complexities inherent to such projects. We characterise and describe firms’ reasons for developing circular economy projects as well as how these projects are funded by using a clinical study focused on three projects. Extant literature presents 3Rs (Reduce, Reuse and Recycle); the reduction of cost and pollution; improvement in competitiveness, innovation, and processes; improvement of ESG ratings, and enhance reputation. All these reasons are positively correlated and address resource scarcity, impact on environment, and economic concerns. Innovative circular projects are typically funded via a mix of sustainable equity - venture capital funds, impact investors, EU funds - and debt - sustainable bonds (green and ESG bonds) and loans.info:eu-repo/semantics/publishedVersio

Análise do ruído de fundo no entorno de aeroportos urbanos em cidades brasileiras, Aeroporto de Congonhas, São Paulo

OBJETIVO Avaliar quantitativamente o ruído de fundo no entorno do aeroporto de Congonhas, com base em ampla amostragem e medições sem interrupção. MÉTODOS Locais de medição escolhidos a partir de curvas de ruído de 62 e 72 LDN (day-night level), em equipamentos urbanos de uso compatível com o residencial. Quinze locais foram avaliados por mais de 168 horas consecutivas cada um (sete dias). A compilação baseou-se em cruzamentos de dados do controle de tráfego aéreo e os resultados foram validados por meio de relatórios meteorológicos do aeroporto. Diagnósticos preliminares foram estabelecidos utilizando a NBR-13368. O ruído de fundo foi calculado com base no Sound Exposure Level (SEL). Os parâmetros estatísticos foram calculados em intervalos de uma hora. RESULTADOS Apenas quatro dos 15 locais avaliados apresentaram clara contribuição da operação de aeronaves no incômodo. Mesmo assim, é possível identificar ruído de fundo acima do regulamentar durante os períodos de baixa atividade ou de fechamento do aeroporto durante a noite. CONCLUSÕES Todos os locais avaliados apresentaram ruído de fundo acima do regulamentar entre 7:00h e 21:00h. Nos intervalos entre 6:00h-6:59h e 21:00h-22:59h, os dados de monitoramento, quando analisados em conjunto com as atuais características operacionais do aeroporto, ainda possibilitam a elaboração de medidas mitigadoras adicionais.OBJECTIVE To perform a quantitative analysis of the background noise at Congonhas Airport surroundings based on large sampling and measurements with no interruption. METHODS Measuring sites were chosen from 62 and 72 DNL (day-night-level) noise contours, in urban sites compatible with residential use. Fifteen sites were monitored for at least 168 hours without interruption or seven consecutive days. Data compilation was based on cross-reference between noise measurements and air traffic control records, and results were validated by airport meteorological reports. Preliminary diagnoses were established using the standard NBR-13368. Background noise values were calculated based on the Sound Exposure Level (SEL). Statistic parameters were calculated in one-hour intervals. RESULTS Only four of the fifteen sites assessed presented aircraft operations as a clear cause for the noise annoyance. Even so, it is possible to detect background noise levels above regulation limits during periods of low airport activity or when it closes at night. CONCLUSIONS All the sites monitored showed background noise levels above regulation limits between 7:00 and 21:00. In the intervals between 6:00-6:59 and 21:00-22:59 the noise data, when analyzed with the current airport operational characteristics, still allow the development of additional mitigating measures

An exact optimization approach for personnel scheduling problems in the call center industry

Nowadays, the importance of the call center industry is increasing because they are a major means of communication between organizations and their customers. So, ensuring optimized personnel schedules in call centers has several advantages, such as reduced total labor costs, overstaffing, increased employee satisfaction, and acceptable waiting times. In this paper, we address the personnel scheduling problem in a 24/7 call center where the scheduling process is done manually. So, the main goal is to explore exact solution approaches to achieve better solutions while reducing the processing time. The proposed optimization model is an Integer Programming model to assign shifts to workers while minimizing the total penalization associated with employees’ time preferences. The model is tested with several instances, including randomly generated and real-world data instances. The quality of the model is assessed through a computational study of its linear relaxation, concluding that the model presents null integrality gaps in all the tested instances. Additionally, to evaluate the performance of the model when running large instances, several randomly generated instances were tested, achieving good computational results.This work has been supported by FCT – Fundação para a Ciência e a Tecnologia within the R&D Units Project Scope UIDB/00319/2020

Net metering: definição de metodologia e estudo de caso

Face à crise económica e financeira, o setor fotovoltaico português tem sofrido diversas condicionantes, na sua maioria políticas, assistindo-se a uma alteração nos regimes de micro e minigeração. Com as tarifas de referência a sofrerem reduções drásticas nos últimos dois anos, os regimes bonificados deixaram de ser economicamente viáveis e interessantes do ponto de vista do consumidor. Esta situação está a pôr em causa as empresas que atuam no setor, assim como o desenvolvimento do próprio mercado fotovoltaico português. Torna-se assim necessário encontrar alternativas aos regimes bonificados, que relancem o setor e que permitam às empresas continuar a trabalhar. Uma dessas alternativas passa pela regulamentação da instalação de unidades de autoconsumo, nomeadamente com soluções de net metering. Dada a região privilegiada onde se encontra Portugal, e ao facto de já ter atingido a paridade de rede solar, o país depara-se com uma oportunidade única para o desenvolvimento da tecnologia fotovoltaica através da implementação de regimes de autoconsumo que interessa avaliar. Neste contexto, desenvolveu-se uma ferramenta informática, que permite, face a um determinado consumidor, avaliar a viabilidade económica e técnica de implementação de soluções de net metering. Uma vez que os resultados são fortemente dependentes da aplicação visada, este trabalho é baseado em dois estudos de caso – setor comercial e residencial – compreendendo a análise de dados reais já existentes e a recolha de dados no terreno. Nesta dissertação, é ainda feito um levantamento sobre os quadros legislativos atualmente vigentes a nível internacional, que regulam o mecanismo de net metering

Cutting and packing : problems, models and exact algorithms

Tese de doutoramento em Engenharia de Produção e Sistemas, área de Investigação OperacionalDifferent integer programming models and exact algorithms for hard cutting and packing problems are addressed. We consider in particular the combinatorial problems of this family that are defined over a single dimension. The optimization procedures rely on tools from the field of integer programming, namely column generation, cutting planes and branch-and-bound. Integrating the three into the same algorithm is not straightforward, and has been used with some success only recently. The combined method is known as branch-and-price-and-cut. It requires a great part of customization, which is directly related to the specific problem that is being tackled. We consider three variants of the standard one-dimensional Cutting Stock Problem, and its packing counterpart, the Bin-Packing Problem. We study the case for which more than a single large object is available, and an optimal cutting or packing has to be found so as to minimize the total length or capacity used. A related problem, which consists in selecting the best assortment of large objects subject to cardinality constraints, is also investigated. The problem of maximizing the homogeneity of the plans, and hence reducing the number of setups involved with its execution, is addressed. This combinatorial problem is commonly referred to as the Pattern Minimization Problem, and is particularly hard. We propose to improve an existing model, and describe how to derive new valid cutting planes for it using an original approach. Finally, we describe an exact solution algorithm for the Ordered Cutting Stock Problem. This problem has been formulated recently. It consists in finding the best assignment of small items to the stock rolls, avoiding breaks among pre-defined lots of items. Three integer programming models are presented, along with two families of cutting planes and their respective separation algorithms. Different strategies are explored to improve the convergence of the column generation algorithm, when applied to one-dimensional cutting and packing problems. New dual cutting planes are presented, and we describe how existing ones can be extended to the whole branch-and-bound search tree, for a given branching scheme. Alternative methods based on model aggregation are also explored. Two strategies are proposed. The first is based on a simple row aggregation scheme, while the second relies on a more sophisticated double aggregation of rows and columns. All the procedures proposed were coded and tested. Various computational experiments were conducted to evaluate their performance, using, with this purpose, problem instances from the literature, and randomly generated instances. The results are presented and discussed throughout the thesis.Au long de cette thèse, nous étudions plusieurs problèemes de découpe et d’empaquetage dont la difficulté est reconnue. Nous considérons en particulier les problèms combinatoires à une seule dimension. Les algorithmes d’optimisation que nous explorons s’appuient sur des méthodes du domaine de la programmation entière, notamment la génération de colonnes, la méthode des plans coupants et la méthode de séparation et évaluation. L’intégration de ces trois méthodes dans un même algorithme ne s’effectue pas directement. En fait, cette intégration n’a été réussie avec succès que très récemment. L’algorithme qui en résulte est connu sous le nom de méthode de séparation, génération de colonnes et plans coupants. Compte tenu du problème qui est abordé, beaucoup d’adaptations sont nécessaires pour parvenir à un algorithme performant. Nous considérons ici les variantes des problèmes standards à une dimension de découpe et d’empaquetage. Nous étudions le cas dans lequel plusieurs objets de grande dimension sont disponibles, et une solution optimale doit être trouvée de manière à minimiser la largeur totale, ou capacité, utilisée. Nous explorons également le problème qui consiste à choisir le meilleur lot d’objets de grande dimension quand il existe des restrictions de cardinalité. La maximisation de l’homogénéité des solutions de découpe, et correspondante minimisation du nombre de changements de patrons de découpe, sont également étudiées. Ce problème est connu sous le nom de Problème de Minimisation des Patrons de Découpes, et il est particulièrement difficil. Nous montrons comment un modèle qui a été récemment proposé peut être amélioré, et nous expliquons comment dériver des inégalités valides en utilisant une approche originale. Finalement, nous décrivons un algorithme de résolution exacte pour le problème de découpe ordonnée. Ce problème a été formulé récemment. Il consiste à trouver la meilleure association des petits et grands objets en évitant qu’il y ait des cassures entre les lots qui ont été prédéfinis. Nous proposons trois modèles de programmation entière, ainsi que deux familles de plans coupants et leurs algorithmes de séparation. Plusieurs stratégies ayant pour but d’améliorer la convergence de la méthode de génération de colonnes sont explorées. Nous considérons le cas particulier où cette méthode est appliquée à des problèmes de découpe et d’empaquetage à une dimension. Nous présentons de nouveaux plans coupants dans l’espace dual, et nous décrivons comment étendre d’autres abordages présentés dans la littérature scientifique à l’arbre généré par la méthode de séparation et d’évaluation, en assumant un schéma de séparation spécifique. Des méthodes alternatives basées sur l’aggrégation de modèles sont aussi explorées. Deux méthodes sont proposées. La première est basée sur un schéma simple d’aggrégation de restrictions, tandis que la seconde s’appuie sur une aggrégation plus sophistiquée de variables et de restrictions. Toutes les procédures proposées ont été programmées et testées. Plusieus expériences computationelles ont été menées pour évaluer leur performance en utilisant, à cet effet, des instances d´ecrites dans la littérature, et des instances générées aléatoirement. Nous présentons les résultats obtenus, et nous les discutons tout au long de la thèse.Nesta tese, são apresentados diferentes modelos de programação inteira e algoritmos de resolução exacta para problemas difíceis de corte e empacotamento. Consideramos em particular os problemas combinatórios dessa família numa única dimensão. Os algoritmos de optimização que exploramos assentam em métodos do domínio da programação inteira, nomeadamente a geração de colunas, planos de corte e o método de partição e avaliação sucessivas. Integrar esses três métodos no mesmo algoritmo não é um exercício directo. Na realidade, isso foi conseguido só muito recentemente. O algoritmo resultante é designado de partição, geração de colunas e corte. Atendendo ao problema que é abordado, várias adaptações têm de ser efectuadas. Consideramos três variantes dos problemas standards de corte e empacotamento com uma dimensão. Estudamos o caso para o qual mais de um tipo de rolos ou contentores estão disponíveis, e uma solução óptima tem de ser encontrada de forma a minimizar a largura ou capacidade total utilizada. Investigamos também um problema relacionado no qual deve ser escolhido o melhor lote de rolos ou contentores atendendo a restrições de carnalidade. O problema no qual se pretende maximizar a homogeneidade das soluções de corte ou empacotamento, e dessa forma minimizar o número de mudanças que ocorrem quando se executa o plano, é analisado. Esse problema combinatório é também conhecido por Problema da Minimização de Padrões, e é de difícil resolução. Propomos melhorar um modelo existente, e descrevemos como derivar planos de corte válidos usando uma abordagem original. Finalmente, descrevemos um algoritmo de resolução exacta para o problema de corte ordenado. Esse problema foi formulado muito recentemente. Consiste em determinar a melhor afectação de itens aos rolos, evitando interrupções entre lotes pré-definidos de itens. Três modelos de programação inteira são apresentados, juntamente com duas famílias de planos de corte e os seus respectivos algoritmos de separação. Diferentes estratégias para melhorar a convergência do método de geração de colunas são exploradas. Consideramos o caso no qual esse método é aplicado a problemas de corte e empacotamento a uma dimensão. Novos cortes duais são apresentados, e descrevemos como cortes que já foram descritos na literatura podem ser extendidos à totalidade da árvore de partição, assumindo um esquema de partição específico. Métodos alternativos baseados em agregação de modelos são também explorados. Duas estratégias são propostas. A primeira é baseada num esquema simples de agregação de restrições, enquanto a segunda assenta num esquema mais sofisticado de restrições e variáveis. Todos os procedimentos propostos foram codificados e testados. Várias experiências computacionais foram levadas a cabo, usando, para isso, instâncias descritas na literatura, e instâncias geradas aleatoriamente. Os resultados são apresentados, e discutidos ao longo da tese

Michoacán and Rio de Janeiro: Criminal Governance, Social Control and Obtaining Profit and Political Power by Armed Self-Defense Groups and Militias

This paper compares two important experiences of the emergence and consolidation of armed non-state actors in Rio de Janeiro, Brazil, and Michoacán, Mexico, noting the rise of the groups, their functioning, relationship with the state and involvement in new forms of governance in territorial control, population regulation and profit-making. These phenomena are part of a broader transformation related to political mutations that decentralize the state and generate specific subjective forms that modify the relationships between the individual, the social, the state, and the market.

From the use of social name to the use of the bathroom: (trans)subjectivities in Brazilian schools

Apresentamos uma reflexão teórica acerca no uso do nome social e do uso do banheiro por estudantes travestis e transexuais na escola pública brasileira. Partimos de uma breve revisão da literatura brasileira, produzida entre 2006 e 2014, sobre o banheiro e o universo trans no campo dos estudos pós estruturalistas de gênero, procurando pontos de convergência e divergência entre os autores e evidenciando possíveis diálogos intertextuais com a política pública do direito ao uso do nome social. A partir do recorte de uma pesquisa realizada numa escola do município de Belo Horizonte/Brasil, percebemos como as (trans)subjetividades produzem resistências no cotidiano educacional, revelando o não lugar de sujeitos travestis e transexuais na escola. Nesse contexto, o uso do banheiro é tomado como um analisador institucional das incongruências de gênero presentes entre a demanda e a norma.We present a theoretical reflection about the use of the social name and the use of the bathroom by transvestites and transsexual students in Brazilian public schools. We begin with a short revision of the Brazilian literature, produced between 2006 and 2014, about the bathroom and the post-structuralist studies of transgender problematics, searching for convergences and deviations among the authors and evidencing possible inter-textual dialogues with the public politics for the right of the use of the social name. From a cross cut of a research held in a public school in the city of Belo Horizonte, Brazil, we realized how the (trans)subjectivities produce resistances in the educational daily life, revealing thenon-place of transvestite and transsexual subjects at schools. In this regard, the use of the bathroom is taken as an institutional analyser of the gender inconsistencies present between demands and rules

Smart and parallel general variable neighborhood search for the pollution-routing problem

This work addresses a new approach to the Pollution-Routing Problem (PRP), a variant of the Vehicle Routing Problem (VRP) under environmental concerns, which includes costs associated with fuel, drivers, and greenhouse gas emissions. The many factors impacting the environment and, simultaneously, the real cost of the routes are usually ignored in the approaches defined to solve routing problems since the total distance traveled remains the standard objective. However, in pollution-routing problems, these elements play an essential role and each one is significantly influenced by the vehicle load and/or speed over the pathways which are followed. To contribute with methods that can provide solutions within an acceptable computational time, we explore local search and meta-heuristic based approaches, with emphasis on a Smart and Parallel General Variable Neighborhood Search algorithm for the PRP. Innovative neighborhood structures allowing continuous speed values in the arcs were a implemented. Additionally, we incorporate parallel programming strategies. To evaluate the effectiveness of these strategies, we report on the computational experiments conducted on benchmark instances, and we compare the results obtained with other studies from the literature.The first author has been supported by FCT – Fundac¸ao para a Ciência e Tecnologia, through national funds from MCTES – Ministerio da Ciência, Tecnologia e Ensino Superior, and by European Social Fund through NORTE2020 – Programa Operacional Regional Norte, within the research grant SFRH/BD/146217/2019. This work has been supported by FCT – Fundação para a Ciencia e a Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

Direito Autoral nos apartamentos e quartos de meios de hospedagem

- Artigo publicado em três partes:Título das partes 2 e 3: Direito Autoral no meios de hospedage