Widening Study of a 45-Meter Tuna Fishing Vessel Based on Multi-Objective Optimization

Stability issues in fishing vessels represent a significant risk to maritime safety, despite advances in stability regulations by the International Maritime Organization (IMO). This paper presents a multi-objective optimization study focused on the widening of a 45.1-meter tuna fishing vessel to improve stability by increasing its beam. The optimization was developed based on the IMO’s Second Generation Stability Criteria (SGSC), evaluating the vessel’s critical failure modes. The Non-Linear Generalized Reduced Gradient (GRG) method method was applied to obtain a balanced solution that improves stability and increases cargo capacity while maintaining operational safety. The vessel\u27s improved performance was validated under operational conditions, demonstrating the feasibility of the proposed modifications

Smart grids as distributed learning control

The topic of smart grids has received a lot of attention but from a scientific point of view it is a highly imprecise concept. This paper attempts to describe what could ultimately work as a control process to fulfill the aims usually stated for such grids without throwing away some important principles established by the pioneers in power system control. In modern terms, we need distributed (or multi-agent) learning control which is suggested to work with a certain consensus mechanism which appears to leave room for achieving cyber-physical security, robustness and performance goals. © 2012 IEEE.published_or_final_versio

Development of a phage-based biosensor to detect Salmonella in food stuff

Tese de doutoramento Programa Doutoral em Engenharia Química e BiológicaFood- and waterborne illnesses are a serious public health concern worldwide and have stimulated research aiming at a rapid and accurate detection of pathogens by applying biosensing technologies. Salmonella, Campylobacter and E. coli are some examples of pathogens that have an enormous impact on public health. Many publications have mentioned different type of biosensors for a broad range of bacteria. These methods may circumvent the limitations that conventional microbiological techniques have. Pathogens of interest need culture enrichment steps to reach the detection limit, a process that requires time, as well as laboratory technicians with expertise skills. Detection of pathogens at a very early stage is not as easy as it seems, due to the necessity to unite a set of characteristics that enable the development of an inexpensive and robust biosensor. The ideal biosensing system should be rapid and accurate and should combine specificity and sensitivity, leading to a marginal amount of false positive or negative results. As the biosensor is composed of two parts, a biological and a sensor element, the biorecognition element of choice plays a crucial role when creating the perfect biosensor. Bacteriophages (or simply phages) are viruses that specifically recognize bacteria and this characteristic can be used as a potential "key" to solve problems related with bacterial detection. Moreover, the easy and low cost production of these viruses combined with their stability in harsh environmental conditions make them excellent competitors with other biological elements (e.g. antibodies, enzymes). The use of phages as a therapeutic agent and as an interface in detection systems has gained special interest of the research community. In many laboratories, phage-based platforms have been developed; however only a few have broken the barrier and went to the market as a clinical diagnostic tool. Nowadays, the food sector still uses conventional methods to detect Salmonella in food stuff that, as mentioned before, take times and requires expert skills. Notwithstanding the great improvements in the detection area, biosensing systems still lack sensitivity and give erroneous results. Furthermore, problems related to the detection of bacteria in a viable but nonculturable (VBNC) state is one of the concerns that can give false negatives. VBNC bacteria are not able to grow on standard bacteriological media, but are metabolically active, albeit very low, maintaining the capacity to cause diseases and therefore remain a potential risk in several health facilities and the food industry. The use of standard microbiological methods to detect if the bacterium is dead or alive is no practicable, since the presence of VBNC state is not detectable. Therefore, novel technologies that can overcome this barrier are imperative. The prevalence of this problem and the necessity of finding a detection technology that can fulfill the Salmonella detection needs, led to the proposal of the present work that explores phages as an interface in a magnetoresistive and magnetoelastic biosensor. The work presented herein describes the characterization of a broad host range lytic phage. PVP-SE1, is able to discriminate between cell viability states, including the VBNC condition. This phage was combined with highly sensitive magnetoresistive sensors originating a powerful detection system with highstandard performance at the accuracy, specificity but also sensitivity level, detecting bacteria concentrations in the order of 100 cells/μL (3-4 cells/sensor). Another strategy followed, aiming at circumventing the limitations of using whole phages in a biosensing interface, was the utilization of recognition peptides of phage origin, responsible for the identification of the hosts. The proof-of-concept was demonstrated with a model phage selected from landscape library as a streptavidin binder. The results showed that the streptavidin binding peptides extracted from the phage bind to streptavidin with the same or better affinity than the native phage. The same was demonstrated with the tail fibre proteins of phage PVP-SE1, heterologously expressed, which showed equal binding affinities compared to their parental phage. This work demonstrates how phages can be explored in the development of a biosensor, opening the possibility of using an accurate, sensitive, specific and cheaper device that can be applied to an emergent concern: foodborne pathogens.As doenças transmitidas através de alimentos e água contaminada são uma preocupação mundial e têm estimulado o desenvolvimento de métodos rápidos e precisos na área dos biossensores para a deteção de agentes patogénicos. Salmonela, Campylobacter e a E. coli são exemplos de espécies bacterianas patogénicos que tem um enorme impacto na saúde pública. Atualmente já existem diferentes tipos de biossensores desenvolvidos para uma ampla variedade de bactérias, que contornam as limitações das técnicas convencionais, tais como tempo de medida, devido à amplificação do microrganismo de interesse no seu adequado meio de cultura, e pela necessidade de técnicos com competências específicas. No entanto, a deteção de agentes patogénicos não é assim tão fácil como parece devido à necessidade de combinar um conjunto de características que permita o desenvolvimento de um biossensor robusto e pouco dispendioso. Um sistema de deteção ideal deve ser rápido, preciso e combinar características como especificidade e sensibilidade, de forma a conduzir a resultados livres de falsos positivos/negativos. Como o biossensor é composto por duas partes, i.e. um elemento biológico e um sensor, o elemento biológico escolhido tem um papel crucial no momento da criação de um biossensor perfeito. Bacteriófagos (ou simplesmente fagos) são vírus que infetam especificamente bactérias podendo essa característica ser utilizada como uma “chave” para solucionar problemas relacionados com a deteção de bactérias. Para além disso, a produção simples e económica destes vírus juntamente com a sua estabilidade em condições ambientais adversas, torna-os excelentes ferramentas de deteção, podendo competir com outros elementos biológicos (e.g. anticorpos, enzimas). A sua utilização como agentes terapêuticos e como interface em sistemas de deteção tem recebido uma atenção especial por parte da comunidade científica. Muitos laboratórios têm desenvolvido plataformas de deteção à base de fagos, no entanto, somente algumas conseguiram quebrar a barreira e entrar no mercado para serem usadas como ferramenta deteção para uso clinico. Hoje em dia, indústrias alimentares ainda usam métodos convencionais para detetar Salmonela na alimentação que, tal como previamente referido, são morosas e exigem mão de obra especializada. Mesmo utilizando diversas estratégias de deteção com diferentes plataformas e bio recetores, problemas com resultados falsos positivos e negativos permanecem difíceis de resolver. Bactérias viáveis, mas não cultiváveis são uma preocupação, porque estão relacionadas com resultados falsos negativos. Bactérias viáveis, mas não cultiváveis, não têm capacidade de crescer em meios de cultura convencional, mas encontram-se metabolicamente ativas, conservando a sua capacidade de causar doenças e de serem um potencial perigo em várias setores da saúde e na industria alimentar. Assim, a utilização de métodos de cultura padronizados para detetar se a bactéria está viva ou morta torna-se inviável, já que a presença de bactérias num estado viável, mas não cultivável não é detetada. Portanto, novas tecnologias que possam ultrapassar essa barreira são fundamentais. A prevalência deste problema e a necessidade de encontrar uma tecnologia de deteção que possa satisfazer as necessidades de deteção da Salmonela conduziu à proposta deste trabalho que explora os fagos como uma possível interface a usar em biossensores magneto-resistivos e magneto-elásticos. O trabalho presentado aqui descreve a caracterização de um fago lítico com um amplo espectro lítico, PVP-SE1. Este fago provou capacidade em discriminar os estados de viabilidade celular incluindo o estado viável, mas não cultivável. O fago foi combinado com sensores magneto-resistivos, que têm mostrado uma elevada sensibilidade. Esta combinação originou um poderoso sistema de deteção com um padrão de desempenho elevado, quer em termos de precisão e especificidade, quer em termos de sensibilidade, detetando concentrações de bactérias na ordem de 100 células/μL (3-4 células/sensor). Uma outra estratégia adotada, tendo por objetivo contornar as limitações da utilização dos fagos inteiros numa interface de um biossensor, passou pela utilização dos recetores dos fagos responsáveis pela identificação dos hospedeiros. Como prova de conceito um fago com especificidade de ligação à streptavidin foi selecionado a partir de uma biblioteca de fagos e usado como modelo. Os resultados demonstraram que os recetores do fago ligam-se à streptavidin com a mesma ou melhor afinidade do que o fago inteiro (original). O mesmo foi demonstrado com os recetores do fago PVP-SE1, demonstrando igualmente afinidades de ligação, comparativamente, com o seu fago parental. Este trabalho demonstrou como os fagos podem ser explorados no desenvolvimento de um biossensor abrindo a possibilidade de desenvolver um dispositivo preciso, sensível, específico e económico que possa ser aplicado a uma preocupação emergente: os patogénicos de origem alimentar

Thermoresponsive fiber-based microwells capable of formation and retrieval of salivary gland stem cell spheroids for the regeneration of irradiation-damaged salivary glands

Three-dimensional spheroid culture enhances cell-to-cell interactions among stem cells and promotes the expression of stem cell properties; however, subsequent retrieval and delivery of these cells remain a challenge. We fabricated a thermoresponsive fiber-based microwell scaffold by combining electrospinning and hydrogel micropatterning. The resultant scaffold appeared to facilitate the formation of cellular spheroids of uniform size and enabled the expression of more stem cell-secreting growth factor genes (EGF, IGF-1, FGF1, FGF2, and HGF), pluripotent stem cell-related genes (SOX2 and NANOG), and adult epithelial stem cell-related genes (LGR4, LGR5, and LGR6) than salivary gland stem cells in a monolayer culture (SGSCmonolayer). The spheroids could be retrieved efficiently by decreasing temperature. SGSC-derived spheroid (SGSCspheroid) cells were then implanted into the submandibular glands of mice at 2 weeks after fractionated X-ray irradiation at a dose of 7.5 Gy/day. At 16 weeks post-irradiation, restoration of salivary function was detected only in SGSCspheroid-implanted mice. The production of submandibular acini specific mucin increased in SGSCspheroid-implanted mice, compared with PBS control. More MIST1+ mature acinar cells were preserved in the SGSCspheroid-implanted group than in the PBS control group. Intriguingly, SGSCspheroid-implanted mice exhibited greater amelioration of tissue damage and preservation of KRT7+ terminally differentiated luminal ductal cells than SGSCmonolayer-implanted mice. The SGSCspheroid-implanted mice also showed less DNA damage and apoptotic cell death than the SGSCmonolayer-implanted mice at 2 weeks post-implantation. Additionally, a significant increase in Ki67+AQP5+ proliferative acinar cells was noted only in SGSCspheroid-implanted mice. Our results suggest that a thermoresponsive fiber-based scaffold could be of use to facilitate the production of function-enhanced SGSCspheroid cells and their subsequent retrieval and delivery to damaged salivary glands to alleviate radiation-induced apoptotic cell death and promote salivary gland regeneration.ope

Optimisation of residential battery integrated photovoltaics system: analyses and new machine learning methods

Modelling and optimisation of battery integrated photovoltaics (PV) systems require a certain amount of high-quality input PV and load data. Despite the recent rollouts of smart meters, the amount of accessible proprietary load and PV data is still limited. This thesis addresses this data shortage issue by performing data analyses and proposing novel data extrapolation, interpolation, and synthesis models. First, a sensitivity analysis is conducted to investigate the impacts of applying PV and load data with various temporal resolutions in PV-battery optimisation models. The explored data granularities range from 5-second to hourly, and the analysis indicates 5-minute to be the most suitable for the proprietary data, achieving a good balance between accuracy and computational cost. A data extrapolation model is then proposed using net meter data clustering, which can extrapolate a month of 5-minute net/gross meter data to a year of data. This thesis also develops two generative adversarial networks (GANs) based models: a deep convolutional generative adversarial network (DCGAN) model which can generate PV and load power from random noises; a super resolution generative adversarial network (SRGAN) model which synthetically interpolates 5-minute load and PV power data from 30-minute/hourly data. All the developed approaches have been validated using a large amount of real-time residential PV and load data and a battery size optimisation model as the end-use application of the extrapolated, interpolated, and synthetic datasets. The results indicate that these models lead to optimisation results with a satisfactory level of accuracy, and at the same time, outperform other comparative approaches. These newly proposed approaches can potentially assist researchers, end-users, installers and utilities with their battery sizing and scheduling optimisation analyses, with no/minimal requirements on the granularity and amount of the available input data

A regional information-based multi-attribute and multi-objective decision-making approach for sustainable supplier selection and order allocation

Although extant studies proposed various models and frameworks for sustainable supplier selection problems, they paid limited attention to the incorporation of regional economic, social, and environmental factors simultaneously for global supply chain design due to the difficulty in reflecting varies dimensions of the global business environment and their associated risk in a decision model. Existing supplier selection models also tend to focus on the formulation of a simplified supply chain structure rather than considering more realistic supply chain operations under multiple sourcing and product designs. To facilitate the complex decision-making process of global supplier selection problems, this study proposes an integrated approach that consists of two phases to effectively reflect the multi-perspectives of global supply chain design for sustainability. The first phase identifies sustainable supplier regions through multi-attribute utility theory, considering four regional sustainability indices for economic and social factors in global business and logistics, to reflect the decision maker\u27s risk attitudes on global business opportunities. In the second phase, a multi-objective integer linear programming model for multiple sourcing and multiple product designs that minimizes economic and environmental objectives is applied to find optimal suppliers in the regions selected from the first phase and their order quantities. The proposed approach is illustrated through a bicycle supplier selection case study. The results show that the multi-objective sustainable decision under a multiple sourcing strategy for different product designs leads to a supply chain that is significantly different from the single-objective non-sustainable decisions. The case study under different decision scenarios shows that a decision maker should hold a balanced perspective under the multi-objective decision environment for sustainable supply chain design

The Oncopig Cancer Model: An Innovative Large Animal Translational Oncology Platform

LTH

SEISMOLOGICAL CONTRIBUTION TO PASSO DELLA MORTE LANDSLIDE CHARACTERIZATION (NORTH EASTERN ITALY)

2013/2014In the North-East of Italy, along the left side of the Tagliamento River, a large area, named Passo della Morte, is involved in several landslides. The western part is characterized by sub-vertical limestone layers and a dense system of discontinuities and fractures, which create ideal conditions for rapid rockfalls. The eastern part of this area is interested by several slides which differ in movement direction and velocity. Their origin is linked to the reactivation of an ancient landslide. The most active blocks move up to 5 cm/year. The main risks are represented by the possible consequence of landslides interaction with the National Road that crosses this area and the Tagliamento River. A microseismicity and acoustic emission monitoring system was installed in the western part of Passo della Morte, inside a tunnel, to monitor the signals generated by rock slope deformation and to recognize precursory phenomena. The system consists of five sensors, two for seismic signal identification and three for acoustic emissions detection. A surface seismometer and a borehole accelerometer arrange the seismic station. Three waveguide with the relative piezoelectric arrange the acoustic emission stations. The orientation of the borehole accelerometer was evaluated indirectly. A program that applied the maximum cross-correlation method and used the surface seismometer as a reference for relative orientation estimation was developed in Fortran90. The analysis of some earthquake allowed the reconstruction of the accelerometer orientation. The microseisms and the acoustic emissions detected by the monitoring system were analyzed and correlated to rainfalls in order evaluate their effects on the rock mass. A direct relation between different rainfall events and sharp increases in microseisms and acoustic emissions was found. Site effects were investigated analyzing seismic noise and earthquake recordings with the Horizontal to Vertical Spectral Ratio method. The seismic noise recorded at different site along the reactivated landslide was analyzed in order to detect the landslide slip surface and reconstruct its geometry. Data processing not give the expected results. The analysis of earthquakes recorded by the surface seismometer showed the absence of amplification able to bring in resonance the unstable rock mass. The cooperation of our research group with Civil Protection Department of Rome allowed to apply at San Giuliano di Puglia seismic stations the same methods used at Passo della Morte in order to estimate relative orientation of the accelerometers and evaluate site effects. The correct orientation of the borehole accelerometers was verified using the program developed. The surface accelerometer was used as reference. Nakamura method was applied at each station to determine the relative resonant frequencies. The resonant frequency found for one site was linked to the bedrock depth. H/V spectral ratio and reference station methods were applied at each station in order to investigate the frequencies strongly amplified. For one site, the amplifications found were very high.Nell’Italia nord occidentale, lungo il versante sinistro del fiume Tagliamento, una vasta area, denominata Passo della Morte, è convolta in diversi fenomeni franosi. La parte più occidentale è caratterizzata dalla presenza di un ammasso roccioso particolarmente suscettibile a crolli a causa delle peculiari caratteristiche dell’ammasso quali stratificazione sub-verticale e denso sistema di discontinuità. La parte più orientale, in seguito alla riattivazione di un’antica frana post glaciale, è interessata dalla presenza di alcuni fenomeni franosi differenti per direzione di movimento e velocità. I movimenti in atto sono dell’ordine di circa 5 cm/anno per i blocchi più attivi. I rischi principali di quest’area sono rappresentati dalle possibili conseguenze dell’interazione delle frane con la strada statale che attraversa quest’area e con il fiume Tagliamento che scorre ai piedi di questo versante. Nella parte più occidentale del Passo della Morte, all’interno di una galleria, è stato installato un sistema di monitoraggio bastato sulla microsismicità e sulle emissioni acustiche al fine di monitorare i segnali prodotti dalla deformazione dell’ammasso roccioso e di riconoscere la presenza di eventuali segnali precursori. Il sistema di monitoraggio si compone di 5 sensori, due per la registrazione di segnali sismici e tre per le emissioni acustiche. Un sismometro in superficie e un accelerometro in pozzo compongono la stazione sismica. Le stazioni delle emissioni acustiche sono composte invece da guide d’onda e dai relativi trasduttori piezoelettrici. L’orientazione dell’accelerometro da pozzo è stata determinata indirettamente sviluppando in Fortran90 un programma che applica il metodo della massima cross-correlazione ed utilizza il sismometro di superficie per determinare l’orientazione relativa. L’analisi di alcuni terremoti attraverso questo programma ha permesso di ricostruire l’orientazione dell’accelerometro all’interno del pozzo. I microsismi e le emissioni acustiche registrate dal sistema di monitoraggio sono state analizzate e correlate con le precipitazioni dell’area al fine di valutare il loro effetto sull’ammasso roccioso potenzialmente instabile. È stata riconosciuta una relazione diretta tra i diversi eventi piovosi e i bruschi incrementi dei microsismi e delle emissioni acustiche. Gli effetti di sito sono stati investigati al Passo della Morte analizzando il rumore sismico e le registrazioni di terremoti con il metodo dei rapporti spetrali H/V. Il rumore sismico registrato in diversi siti posti sull’antica frana riattivata è stato analizzato per individuare la superficie di scivolamento della frana e ricostruire la sua geometria. L’elaborazione dei dati non ha prodotto i risultati sperati. L’analisi dei terremoti registrati dal sismometro in superficie ha mostrato l’assenza di amplificazioni tali da poter mandare in risonanza l’ammasso roccioso. La collaborazione del nostro gruppo di ricerca con il Dipartimento della Protezione Civile di Roma ha permesso di avere accesso ai dati delle tre stazioni accelerometriche di San Giuliano di Puglia e di applicare i metodi usati al Passo della Morte per determinare l’orientazione relativa degli accelerometri e per valutare gli effetti di sito. La corretta orientazione degli accelerometri da pozzo è stata verificata attraverso l’utilizzo del programma sviluppato. L’accelerometro in superficie è stato usato come riferimento. Il metodo di Nakamura è stato utilizzato in ciascuna stazione per determinare le relative frequenze di risonanza. La frequenza di risonanza ottenuta per un sito è stata associata alla profondità del bedrock. I metodi dei rapporti spettrali H/V e della stazione di riferimento sono stati applicati a ciascuna stazione per investigare le frequenze maggiormente amplificate. Per un sito le amplificazioni trovate sono risultate molto elevate.XXVII Ciclo198