Reutilização de águas resultantes da produção de explosivos: caso de estudo empresa “X”

Dissertação de mestrado, Engenharia do Ambiente, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016As águas residuais resultantes da produção dos explosivos da empresa “X” caraterizam-se físico-quimicamente por conterem uma elevada carga orgânica (5922 mg O2 L-1) com muito reduzida biodegradabilidade (CBO5/CQO = 0,009), concentrações de azoto muito elevadas (1553,9 mg N-NH4+ L-1 e 7233 mg NO3- L-1) e um teor de óleos e gorduras de 285,3 mg L-1. Com objetivo de tratar este efluente, desenvolveu-se um sistema de tratamento, que consistiu na precipitação química em meio básico com Ca(OH)2, carbonatação natural e afinação em zona húmida artificial plantada com Vetivera zizanioides. No processo de precipitação química estudou-se o efeito da dose de cal sobre vários parâmetros físico-químicos, tendo sido escolhida a dose de Ca(OH)2 de 7,76 g L-1 que eleva o pH da água a 10, resulta num efluente límpido e permite atingir remoções de CQO de 92%, óleos e gorduras de 98% e elimina totalmente a matéria orgânica azotada. O sobrenadante obtido apresenta um pH de cerca de 10 e foi neutralizado numa etapa de carbonatação com CO2 atmosférico. Ao fim de 11 dias conseguiu-se a remoção simultânea de 61 % de NH4+, que lhe confere potencialidades para ser utilizado como fertilizante em fertirrega. A etapa de precipitação produziu um precipitado abundante que sedimenta em manto para tempos de retenção hidráulica de 46 minutos com uma percentagem de lamas reduzida, 4,5 %. Adicionalmente foi avaliada a possibilidade de tratamento por zonas húmidas artificais com Vetivera zizanioides sob fluxo sub-superficial vertical, o que permitiu conhecer os processos biológicos envolvidos por análise de vários parâmetros, conhecer as melhores condições operatórias aplicadas para remover maiores cargas mássicas de azoto amoniacal e de nitratos. Apesar de o tratamento proposto ser viável, os resultados evidenciaram que ainda há necessidade de fazer melhorias no tratamento proposto na remoção de azoto amoniacal, matéria orgânica e nitratos

Reutilização de águas resultantes da produção de explosivos: caso de estudo empresa “X”

Dissertação de mestrado, Engenharia do Ambiente, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016As águas residuais resultantes da produção dos explosivos da empresa “X” caraterizam-se físico-quimicamente por conterem uma elevada carga orgânica (5922 mg O2 L-1) com muito reduzida biodegradabilidade (CBO5/CQO = 0,009), concentrações de azoto muito elevadas (1553,9 mg N-NH4+ L-1 e 7233 mg NO3- L-1) e um teor de óleos e gorduras de 285,3 mg L-1. Com objetivo de tratar este efluente, desenvolveu-se um sistema de tratamento, que consistiu na precipitação química em meio básico com Ca(OH)2, carbonatação natural e afinação em zona húmida artificial plantada com Vetivera zizanioides. No processo de precipitação química estudou-se o efeito da dose de cal sobre vários parâmetros físico-químicos, tendo sido escolhida a dose de Ca(OH)2 de 7,76 g L-1 que eleva o pH da água a 10, resulta num efluente límpido e permite atingir remoções de CQO de 92%, óleos e gorduras de 98% e elimina totalmente a matéria orgânica azotada. O sobrenadante obtido apresenta um pH de cerca de 10 e foi neutralizado numa etapa de carbonatação com CO2 atmosférico. Ao fim de 11 dias conseguiu-se a remoção simultânea de 61 % de NH4+, que lhe confere potencialidades para ser utilizado como fertilizante em fertirrega. A etapa de precipitação produziu um precipitado abundante que sedimenta em manto para tempos de retenção hidráulica de 46 minutos com uma percentagem de lamas reduzida, 4,5 %. Adicionalmente foi avaliada a possibilidade de tratamento por zonas húmidas artificais com Vetivera zizanioides sob fluxo sub-superficial vertical, o que permitiu conhecer os processos biológicos envolvidos por análise de vários parâmetros, conhecer as melhores condições operatórias aplicadas para remover maiores cargas mássicas de azoto amoniacal e de nitratos. Apesar de o tratamento proposto ser viável, os resultados evidenciaram que ainda há necessidade de fazer melhorias no tratamento proposto na remoção de azoto amoniacal, matéria orgânica e nitratos

Optimization of atmospheric carbonation in the integrated treatment immediate one-step lime precipitation and atmospheric carbonation. The case study of slaughterhouse effluents

Long carbonation time has been a common feature in the integrated process composed by immediate one-step lime precipitation and atmospheric carbonation. This work aims to understand how carbonation time can be influenced by reaction pH, as well as how reactor area/volume ratio affects carbonation time and ammonia removal, using slaughterhouse wastewater due to its variable characteristics. In the integrated immediate one-step lime precipitation and atmospheric carbonation process, the immediate one-step lime precipitation re-sults showed that the reaction pH and the type of slaughterhouse wastewater influenced the removal, however, removals were the highest at reaction pH 12. In atmospheric carbonation process, the carbonation time required to reach pH 8 was independent of the reaction pH used. Additionally, at reaction pH 12, the reactor area/volume ratios applied (from 0 to 155.4 m2/m3) showed that higher reactor area/volume ratios caused lower carbonation time, but ammonia removal was not affected. For reactor area/volume ratios of 5 and 155.4 m2/m3, 15 and 1 days were spent to reduce the pH from 11.9 to 8.2, with removals of 71 and 82.6% for NH4+ and 10 and 79.1% for calcium, respectively. High removals of total Kjeldahl nitrogen (>= 71%), biological oxygen demand (>= 80%), ammonium nitrogen (>= 52%), total phosphorus (98%), total suspended solids (>= 52%), turbidity (>= 62%), absorbance at 254 nm (>= 87%), absorbance at 410 nm (>= 83%) and oils & fats (>= 47%) were obtained using immediate one-step lime precipitation and atmospheric carbonation integrated process to treatment slaughter-house wastewater, indicating that the these process is an efficient pretreatment for slaughterhouse wastewaters.info:eu-repo/semantics/publishedVersio

On the physical layer security characteristics for MIMO-SVD techniques for SC-FDE schemes

partially supported by the FCT -Fundacao para a Ciencia e Tecnologia and Instituto de Telecomunicacoes under projects UID/EEA/50008/2019. PES3N POCI-01-0145-FEDER-030629.Multi-Input, Multi-Output (MIMO) techniques are seeing widespread usage in wireless communication systems due to their large capacity gains. On the other hand, security is a concern of any wireless system, which can make schemes that implement physical layer security key in assuring secure communications. In this paper, we study the physical layer security issues of MIMO with Singular Value Decomposition (SVD) schemes, employed along with Single-Carrier with Frequency-Domain Equalization (SC-FDE) techniques. More concretely. the security potential against an unintended eavesdropper is analysed, and it is shown that the higher the distance between the eavesdropper and the transmitter or receiver, the higher the secrecy rate. In addition, in a scenario where there is Line of Sight (LOS) between all users, it is shown that the secrecy rate can be even higher than in the previous scenario. Therefore, MIMO-SVD schemes combined with SC-FDE can be an efficient option for highly secure MIMO communications.publishersversionpublishe

Does the age of entry in primary school affect student’s achievement?

proofpublishe

A physical layer security technique for NOMA systems with MIMO SC-FDE schemes

PES3N POCI-01-0145-FEDER-030629Current wireless communication systems employ Multi-Input, Multi-Output (MIMO) techniques to increase spectral efficiency, at the cost of higher hardware complexity. Most of these systems continue to employ traditional Orthogonal Multiple Access (OMA) schemes, which are suboptimal when compared to Non-Orthogonal Multiple Access (NOMA) schemes. By combining NOMA with MIMO, it is possible to achieve higher spectral efficiencies. However, security in NOMA-MIMO systems remains a problem. In this paper, we study the physical layer security issues of a power based NOMA-MIMO system with a Singular Value Decomposition (SVD) scheme, employed along with Single Carrier with Frequency Domain Equalization (SC-FDE) techniques. We consider a scenario where there is an unintended eavesdropper attempting to listen to the messages being exchanged. It is shown that the higher the channel estimate correlation between transmitter and receiver, the higher the secrecy rate, particularly for a scenario where there is a Line-Of-Sight (LOS) between all users. Therefore, power based NOMA MIMO-SVD schemes, combined with SC-FDE, can be considered efficient options for highly secure MIMO communications.publishersversionpublishe

Gastrointestinal parasitism in Miranda donkeys : epidemiology and selective control of strongyles infection in the Northeast of Portugal

Research Areas: Agriculture ; Veterinary Sciences ; ZoologyIn Portugal, equine parasitism in pasture animals is characterized by high parasitic burden and high helminthic biodiversity; both factors are potentially pathogenic for their hosts. The decrease in the number of donkeys over the last years in Portugal, their importance in rural lowland and mountain ecosystems and pastures and the scarce information regarding their parasitism led to this research, which aimed to evaluate the parasitological status of a Miranda donkey breed population, a native breed mainly located in the northeast of Portugal. This study provides better knowledge of their gastrointestinal parasitism, particularly strongyles, and the assessment of a targeted selective treatment (TST) as an alternative control approach of their parasitism. A longitudinal observational study was developed during a period of five years in a population of 62 Miranda donkeys. At first, strategic deworming of these animals was performed every semester, but this was progressively replaced by a TST approach according to the levels of Eggs per Gram (EPG). This new deworming strategy was conducted in association with a regular parasitological monitoring of the animals every three months, being dewormed with ivermectin when egg shedding was higher than 500 EPG. Over the study period, a decrease of the annual prevalence rate of infection by gastrointestinal strongyles was observed, from 35.5% to 19.4%, as well as a negative binomial distribution of parasitic strongyles in donkeys submitted to selective anthelminthic control. The prevalence rate of infection was higher in females (39.5%), in individuals under four years (46.7%) and in those presenting a lower body condition (40.8%). The egg output was higher in animals younger than four years (589.3 EPG) than in those older than 10 years (533.6 EPG) (p < 0.05). However, no differences were observed according to sex during the study period. Results from this study allowed to note the influence of swampy pastures and of the weather changes in the epidemiology of strongylosis in Miranda donkeys. Moreover, it was possible to establish the annual epidemiological curve of strongyle egg shedding, with June being the month with the highest EPG, December having the lowest EPG and March and September showing intermediate numbers. Overall, a lower biodiversity of gastrointestinal parasites was observed. Cyathostomum sensu lato was the most prevalent genus and Strongylus vulgaris was the most observed large strongyle of the Strongylidae family. Trichostrongylus axei and Parascaris sp. were other nematodes with a minor frequency. The higher prevalence of strongyles at the beginning of the study showed a progressive decrease throughout the research period, and also for parasite biodiversity. Therefore, a targeted selective treatment seems to be a rational anthelminthic control approach in Miranda donkey strongyle infection and in other gastrointestinal parasites, since it reduces the antiparasitic treatments, the parasite’ prevalence and the EPG level. However, a loss of parasite biodiversity was noted at the end of the study period, as Cyathostominae were the only isolated strongyles. This can be a challenging situation in the long run, taking the ability of these nematodes to adapt easily to any deworming program, meaning that fecal EPG monitoring should be kept as a rule to a rational parasite control program.info:eu-repo/semantics/publishedVersio

Sensory profiling of complex meals : the case study of baked cod with cream and duck

Sensory analysis provides important information for developing new products and improving existing ones on the market. In fact, this science appears as a link between research and the development of innovative foods and their acceptance by the consumer [1]. The main purpose of this study is to evaluate the effectiveness of sensory methodologies for profiling of complex meals such as baked cod with cream and duck rice. Evaluation was performed with two sets of eight samples of industrial cod with cream and duck rice. Two independent trained panels of 9 and 12 judges evaluated the samples according to Quantitative Descriptive Analysis (QDA). Two independent panels of 16 untrained judges applied the Flash-Profile (FP) methodology over four sessions: attribute generation; final attribute list choice; evaluation 1 and 2. Two consumer panels evaluated the overall acceptance of each set of samples, on a sequential monadic presentation. For duck rice meals, the correlation between QDA and FP was not high (RV=0,646), and consumers preferred samples characterized by rice colour intensity, amount of duck, oiliness, bacon and chorizo in the meal. For cod with cream meals, the consumers preferred the samples characterized by amount and size of the cod pieces and intensity of cod taste, with a high correlation between FP and QDA (RV=0,860). Both sensory descriptive methodologies provide us with reliable and robust data in the characterization of complex meals. The FP methodology is relevant when working with panels of consumers to the extent that allows it to use their own lexicon of attributes. The application of external preference mapping on consumers’ response to FP emerges as a quick tool, either to describe products or to be used by food companies that have difficulties in using trained assessors’ panels. References: [1] Siegrist, M. (2008) Factors influencing public acceptance of innovative food technologies and products. Trends in Food Science & Technology, 19, 603-608

Shape effects of ceria nanoparticles on the water-gas shift performance of cuox /ceo2 catalysts

T1EDK-00094 UIDB/EQU/50020/2020 UIDB/00511/2020 CEECINST/00102/2018 UIDB/50006/2020 UIDP/50006/2020 DL 57/2017The copper–ceria (CuOx /CeO2 ) system has been extensively investigated in several catalytic processes, given its distinctive properties and considerable low cost compared to noble metal-based catalysts. The fine-tuning of key parameters, e.g., the particle size and shape of individual counterparts, can significantly affect the physicochemical properties and subsequently the catalytic performance of the binary oxide. To this end, the present work focuses on the morphology effects of ceria nanoparticles, i.e., nanopolyhedra (P), nanocubes (C), and nanorods (R), on the water–gas shift (WGS) performance of CuOx /CeO2 catalysts. Various characterization techniques were employed to unveil the effect of shape on the structural, redox and surface properties. According to the acquired results, the support morphology affects to a different extent the reducibility and mobility of oxygen species, following the trend: R > P > C. This consequently influences copper–ceria interactions and the stabilization of partially reduced copper species (Cu+ ) through the Cu2+ /Cu+ and Ce4+ /Ce3+ redox cycles. Regarding the WGS performance, bare ceria supports exhibit no activity, while the addition of copper to the different ceria nanostructures alters significantly this behaviour. The CuOx /CeO2 sample of rod-like morphology demonstrates the best catalytic activity and stability, approaching the thermodynamic equilibrium conversion at 350◦ C. The greater abundance in loosely bound oxygen species, oxygen vacancies and highly dispersed Cu+ species can be mainly accounted for its superior catalytic performance.publishersversionpublishe