Physical processing efficiency of saline vs. alkaline spent batteries

Physical processing of spent batteries which includes shredding and sieving operation is the first step for chemical treatment by hydrometallurgy. A laboratory study was carried out to evaluate physical processing efficiency, by analysing the resulting particle size, of alkaline and saline mignon-type Zn-MnO2 batteries. After shredding with a tip shredder, results obtained showed that alkaline batteries were more efficiently size reduced than saline batteries. Difference in particle size distribution was larger for granulometric fraction -20+11.2 mm and also higher for saline batteries. Average diameters (d50) for saline and alkaline batteries were respectively 9.1 and 6.2 mm. Chemical composition carried out on several granulometric fractions allowed to identify metals distribution through size categories. This analysis showed that zinc concentration with the grain size was almost constant, while manganese decreased when particle size increased. More than 95% of iron scarp from the battery cases had a particle size higher than 5.6 mm

Carbon molecular sieve membranes for gas separation : study, preparation and characterization

Tese de doutoramento. Engenharia Química e Biológica. Faculdade de Engenharia. Universidade do Porto. 200

Machine learning approach for personalized recommendations on online platforms: uniplaces case study

Project Work presented as the partial requirement for obtaining a Master's degree in Information Management, specialization in Knowledge Management and Business IntelligenceThe goal of this project is to develop a model to personalize the user recommendations of an online marketplace named Uniplaces. This online business offers properties for medium and long-term stays, where landlords can directly rent their place to customers (mainly students). Whenever a student makes a reservation, the booking must be approved by the property owner. The current acceptance rate is 25%. The model is a response to this low acceptance rate, and it will have to show to each student the properties that are more likely to be accepted by the landlord. As a secondary objective, the model seeks to identify the reasons behind the landlord’s decision to accept or reject bookings. The model will be constructed using information from the users, landlord and the property itself kindly provided by Uniplaces. This information will pre-process with data cleaning, transformation and features reduction (where two techniques were applied: dimensionality reduction, features selection). After the data processing, several models were applied to the normalized data. The predictive models that will be applied are already being used on other online markets and platforms like Airbnb, Netflix or LinkedIn, namely Support Vector Machine, Neural Networks, Decision Tree, Logistic Regression and Gradient Boosting. The probability of acceptance proved to be very easy to predict, all the models predict 100% of the test dataset when using the Principal Component Analysis as the Dimensionality Reduction technique. This can be explained mainly by the fact that the new calculated features have a strong correlation with the target variable. All the algorithms predict 100% of the target variable when using Principal Component Analysis as a technique of dimensionality reduction

Leaching behavior of several zinc rich residues in a hydrometallurgical recycling process

The leaching of metals contained in spent Zn-MnO2 batteries and electric arc furnace (EAF) dusts using sulfuric acid solutions was studied, in order to evaluate the feasibility of simultaneous treatment of both wastes by a hydrometallurgical process. In both residues, a substantial quantity of zinc was solubilized (about 100% in batteries and 70-80% in EAF dusts) in diluted acid solutions and room temperature, corresponding to the reaction of zinc oxide species. Other species were more refractory to the chemical attack, namely the manganese (III or IV) oxides in batteries and the zinc ferrite in dusts, requiring higher temperatures (e.g. 90ºC) and higher leachant concentrations. Lead present in EAF dusts was not solubilized in sulfate media, thus remaining in the leach residue. Results seem to confirm the possibility of treatment of both zinc-containing residues by the same hydrometallurgical process, eventually involving two leaching stages – diluted acid leaching and hot acid leaching – followed by solution purification through iron precipitation and Zn/Mn separation and recovery. Concerning lead, a second leaching circuit in chloride media could be developed for its potential recovery

Water Supply Infrastructure Cost Modelling

AbstractThe current paper presents the development and validation of cost functions for different types of assets of water supply systems based on known hydraulic (e.g., flow, pump head, pump power) and physical characteristics of the assets (e.g., volume, material, nominal diameter). The followed methodology is a five-step procedure: 1) database construction and analysis, 2) present cost value calculation, 3) cost function establishment, 4) model specification, and 5) model validation. Cost and infrastructure data from several Portuguese water utilities have been used. Regression models have been used for the cost modelling

Caraterização das lesões desportivas em jogadores da 1ª divisão de futebol feminino em Portugal

Introdução: O crescimento exponencial do futebol feminino associado ao aumento de intensidade e agressividade e à execução de movimentos explosivos aumentou consideravelmente o risco de lesão. Objetivo(s): Para um melhor entendimento da caracterização das lesões desportivas no futebol feminino é condição necessária o conhecimento dos fatores de risco intrínsecos e extrínsecos com vista à prevenção de lesões. É essencial estudar os diferentes contextos e procurar estratégias de prevenção de lesão que se coadunem com a disponibilidade e oportunidades do futebol feminino a nível nacional. Métodos: Foi realizado um estudo observacional analítico retrospetivo, tendo sido aplicado um questionário às jogadoras federadas inscritas na primeira divisão do campeonato nacional na época de 2015/2016. O questionário visava a caracterização das atletas, da atividade, do contexto e das lesões. A presença de lesão foi utilizada como variável de divisão das atletas. Foi também aplicado um questionário aos treinadores para verificar a sua perceção do contexto em estudo. A análise estatística foi realizada através do software IBM SPSS Statistics® versão 23, com um nível de significância de 0,05, sendo que foram utilizadas as frequências absoluta e relativa, média e respetivo desvio padrão, o teste e o teste Qui-Quadrado. Resultados: Das 121 respostas ao questionário, 74 jogadoras sofreram lesões, tendo sido contabilizadas um total de 105. Os locais mais afetados são o joelho, a anca/coxa e o tornozelo. Os treinadores não apresentaram respostas concordantes com as atletas no que se refere ao número de lesões, e de um modo geral aplicaram métodos de prevenção de lesão durante a época. Conclusão: O tipo e local anatómico de lesão são condizentes com a informação expressa noutros estudos, quer no futebol feminino, quer no masculino. No entanto, as condicionantes anatómicas das mulheres potenciam as lesões ligamentares que necessitam de estratégias de prevenção adequadas

Relatório de clínica de animais de companhia: hérnia diafragmática peritoneo-pericárdica

Este relatório insere-se no âmbito do Mestrado Integrado em Medicina Veterinária da Universidade de Évora e é constituído por duas partes fundamentais. A primeira parte do relatório engloba todas as atividades desenvolvidas e casuística observada durante o estágio curricular realizado nas instalações veterinárias Montenegro, referentes à clínica de animais de companhia. A segunda parte consiste na revisão bibliográfica de hérnia diafragmática peritoneo-pericárdica. Esta hérnia é considerada a malformação congénita pericárdica e diafragmática mais comum em cães e gatos, apresentando um prognóstico favorável se for corrigida precocemente. A revisão bibliográfica é seguida da descrição e discussão de um caso clínico num canídeo acompanhado durante o período de estágio; Abstract: Small Animal Medicine: Peritoneopericardial Diaphragmatic Hernia This report falls within the scope of the Master`s Degree in Veterinary Medicine, University of Évora and consists of two main parts. The first section of this report includes all the developed activities as well as the number of cases that were followed during the internship performed at the Montenegro veterinary hospital (Small animal clinic). The second part consists of a literature review on the peritoneopericardial diaphragmatic hernia. The hernia is considered the most common congenital pericardial diaphragmatic disorders/malformations both in dogs and cats, with a favorable prognosis if early corrected. The literature review is followed by the description and discussion of a follow up clinical case in a dog accompanied during the internship period