https://hdl.handle.net/10216/156 2026-07-14T23:47:40Z https://hdl.handle.net/10216/171250 Title: Environmental and Nutritional Sustainability of Diets: Exploring Food Consumption Patterns Between Different Sustainability Groups Abstract: Food sustainability is a vital global challenge, as dietary choices affect both human health and the environment. This study evaluates Portuguese dietary patterns' environmental and nutritional sustainability dimensions using data from the National Food, Nutrition, and Physical Activity Survey (IAN-AF) 2015-2016. Environmental indicators (carbon footprint, water footprint, and land use) and a nutritional quality index (NRD9.3) were analysed. Sustainability scores were calculated based on deviations from population medians, with the environmental score estimated from a weighted mean of the three indicators. A quadrant analysis classified individuals into four sustainability segments: better environmental and better nutritional scores (reference group); worse environmental and worse nutritional scores; worse environmental and better nutritional scores; and better environmental and worse nutritional scores. The reference group, with higher plant-based food consumption, had the lowest environmental impacts, 33% lower carbon footprint, 36% lower water footprint, and 50% lower land use, while exhibiting 87% better nutritional quality. In contrast, the worse environmental and worse nutritional scores group, with a diet rich in red and processed meats, sweets, and alcohol, showed higher environmental impacts and poorer nutritional quality. The group with worse environmental and better nutritional scores favored dairy and seafood, whereas the group with better environmental and worse nutritional scores had higher intakes of white meat, sweets, and alcohol. Sociodemographic factors, including sex, age, and education, show to influence the sustainability dimensions. These findings highlight the need for tailored dietary strategies that consider differing environmental and nutritional profiles, supporting more effective and practical public health interventions. 2026-01-01T00:00:00Z https://hdl.handle.net/10216/174875 Title: On the Structural Distortion Induced by the Inverse Box-Cox Transformation 2026-07-10T00:00:00Z https://hdl.handle.net/10216/174864 Title: Development of a modelling framework for running safety analysis of a heavy-haul freight vehicle crossing a bridge under different loading conditions Abstract: Evaluation of train running safety for freight and heavy-haul railway vehicles is a poorly addressed topic in the literature, despite their distinct dynamic behaviour and track conditions compared with passenger and high-speed railways. For this purpose, a framework for the development of a three-dimensional numerical analysis of train running safety crossing a bridge using a vehicle-structure interaction methodology is presented. Numerical models of the railway bridge were developed and calibrated, and multibody models of the heavy-haul vehicles were created and optimised based on modal data. Structure and vehicle dynamic responses were obtained using the dynamic interaction models that consider nonlinear wheel-rail contact models. Assessment of structural and train running safety was performed for multiple train speeds for both loaded and unloaded vehicles using different degrees of rail geometric irregularities based on the Federal Railroad Administration's power spectral density functions. The case study is a 550-metre-long railway bridge composed of 22 simply supported steel-concrete composite spans, crossed by heavy-haul vehicles of the gondola-type wagon with 375 kN axle loads. The safety of the bridge was assessed in terms of structural responses according to European codes, while the running safety of the vehicle was evaluated through indirect running safety indices as well as direct derailment coefficients based on vertical and lateral wheel-rail contact forces and more advanced criteria. It was found that in regular operational conditions, all indices are well below recommended limit values for loaded vehicles, whereas the unloaded vehicles presented a more unstable dynamic behaviour. 2026-07-09T00:00:00Z https://hdl.handle.net/10216/174791 Title: Transport disadvantage and accessibility gaps: Addressing equity in Porto's metropolitan public transport system 2026-12-01T00:00:00Z https://hdl.handle.net/10216/174752 Title: Intermodal versus monomodal travellers: Evidence from a comparative study in Porto 2026-09-15T00:00:00Z https://hdl.handle.net/10216/166661 Title: Assessment of integrated rail and bus transport network design: Equity and efficiency perspectives Abstract: Recognizing the vital role of public transport (PuT) in accessibility, inclusivity, and quality of life, its planning must balance efficiency with equitable service coverage. This study examines PuT network design, integrating rail and bus services while incorporating equity considerations for a more efficient and socially equitable system. Despite extensive research on PuT network design (PTND), balancing these objectives remains a key challenge in transit planning. This paper presents a methodological framework that integrates PTND with Data Envelopment Analysis (DEA) to design and evaluate multiple PTND scenarios. These scenarios are assessed using equity-based perspectives: potential demand (PD), adjusted demand (AD), and transport needs (TN). The approach identifies efficient designs that maximize service coverage and social equity, addressing varying population demands and needs. The methodology is demonstrated through a case study in the metropolitan area of Porto (AMP), offering policymakers insights into PuT equity implications for the infrastructure planning and decision-making process. Two output-oriented DEA models were developed: one using service coverage adequacy (SCA) as output and another incorporating both SCA and the GINI coefficient (equity) to assess the impact of different equity perspectives on system efficiency. Results indicate that network designs based on AD performed better with higher efficiency scores than PD and TN, suggesting that AD better captures PuT demand needs and supports equitable service distribution. The findings emphasize the need to integrate population equity perspectives and multimodal transport to create more balanced and efficient PuT systems, ensuring fair access to mobility for diverse populations in the region. 2025-01-01T00:00:00Z https://hdl.handle.net/10216/82505 Title: Metodologia para avaliação dos fatores condicionantes da velocidade em regime livre em ambiente periurbano Abstract: This paper presents a new methodology for the evaluation of the effects of posted speed limit, geometric and environmental characteristics on free-flow speed in transition zones, through a macroscopic analysis. A vehicle travels under free-flow conditions if its chosen speed is not affected by the presence of the vehicle ahead. In this sense, the free-flow speed reflects the driver's response to road geometric and environmental characteristics. In the first stage of the proposed methodology, new macroscopic variables reflecting the characteristics of transition zones are created through the use of multivariate data analysis techniques, namely analysis of clusters and principal component analysis. In the second stage, a regression analysis is performed in order to compare the effects of different variables on the adopted free-flow speed. This methodology is then tested for a set of 27 sites located in Portuguese two-lane highways, where drivers' speed, the existence of posted speed limit and some geometric and environmental microscopic characteristics were collected. Description: Neste artigo, apresenta-se uma metodologia para a avaliação macroscópica da influência das características geométricas e ambientais e da sinalização de velocidade limite legal na velocidade em regime livre praticada pelos condutores em zonas periurbanas ou de transição. Um condutor circula em regime livre quando a sua escolha de velocidade não é condicionada pela presença do veículo precedente. Assim, a velocidade adotada reflete a sua resposta face às características da estrada e do ambiente envolvente. A metodologia consiste na utilização de métodos estatísticos de análise de dados multivariados, nomeadamente de classificação e de análise em componentes principais, para a definição de variáveis macroscópicas caracterizadoras das zonas periurbanas, sobre as quais é depois efetuada uma análise de regressão que permite a avaliação dos impactos das diferentes variáveis na velocidade em regime livre. A metodologia proposta é aplicada a um conjunto de 27 locais pertencentes a estradas de duas vias situadas em Portugal, onde foram observadas as velocidades praticadas, a existência de sinalização de limite legal de velocidade e diversas variáveis microscópicas caracterizadoras da geometria e do ambiente. 2012-01-01T00:00:00Z https://hdl.handle.net/10216/174597 Title: Recycled Textile Fibres from Waste Tyres in Concrete: Mechanical Performance, Durability, and Sustainability Review 2026-06-19T00:00:00Z https://hdl.handle.net/10216/129572 Title: INTEGRATED STRUCTURAL SISING OPTIMIZATION Abstract: A formulation for structural sizing optimization is presented. The method includes the displacements as state variables and thus integrates the analysis and design process into one combined step. The equilibrium equations are then used as equality constraints in an Augmented Lagrangian formulation. The method currently handles displacement constraints. Stress and ductility constraints are being added as well as general finite element capabilities. 1987-01-01T00:00:00Z https://hdl.handle.net/10216/162958 Title: A Geometric Approach for the Calculation of the Nonrandomness Factor Using Computational Chemistry Abstract: The nonrandomness factor (alpha) is a parameter related to the polarity (and consequent randomness of spatial orientation) of the molecules and is generally fixed between 0.20 and 0.47 since no technique has been developed so far for its accurate estimation. However, the consideration of a constant nonrandomness factor for mixtures is known to harden azeotrope description and to cause convergence issues in both the Nonrandom Two-Liquid (NRTL) and Universal Quasi-chemical (UNIQUAC) models, which have been widely applied in the correlation of phase equilibria. In this work, a novel geometric methodology, named Porto's approach, was applied in the calculation of the nonrandomness factors for 50 pure components (mainly alkanes, alcohols, and ketones) at 298.15 K and 0.1 MPa. This methodology relied on computational chemistry (Density Functional Theory, DFT) to minimize the energy of molecules in a cavity within a solvent composed of molecules of their own (applying the Polarizable Continuum Model, PCM), and thereafter define the most stable chemical configuration in the pure liquid state. Then, the nonrandomness factor of each component was determined based on its molecular dipole moment, which was calculated after a population analysis of the optimized partial electrical charges with the Natural Bond Orbital (NBO) function. This innovative approach was applied in the correlation of liquid-liquid equilibria (LLE) data for 15 ternary systems comprising only neutral molecules with NRTL and UNIQUAC. The classical methods (alpha = 0.2 or 0.3 for NRTL and alpha = 0.2 for UNIQUAC) were compared against the usage of a component-specific nonrandomness factor, and similar standard deviations were obtained. Hence, this work is considered a strong advance in the application of these excess free Gibbs energy models to phase equilibria estimation and opens the door to more accurate thermodynamic modeling of nonideal mixtures (such as the ones containing electrolytes) by providing enhanced physical meaning to the nonrandomness factors. 2023-01-01T00:00:00Z https://hdl.handle.net/10216/137189 Title: Study of Liquid-Liquid Equilibrium of Aqueous Two-Phase Systems Based on Ethyl Lactate and Partitioning of Rutin and Quercetin Abstract: Two ethyl lactate (EL)-based aqueous two-phase systems (ATPSs) were studied at T = 298.15 K and atmospheric pressure. Sodium tartrate and potassium sodium tartrate organic salts have been used to form biphasic systems. To assess the phase splitting, binodal curves and tie-lines were obtained experimentally by the cloud point method and a technique, which consist of the density and refractive index, respectively. Binodal curves were fitted with the Merchuk equation obtaining a good fit. Moreover, modeling with the universal quasichemical thermodynamic equation was carried out to accurately represent the two-biphasic systems. Furthermore, experimental binodal curves obtained in this work and literature results for the same systems and for systems with EL and other salts were analyzed regarding their similarity. Finally, the application of the adopted ATPS in the partitioning of two flavonoids, rutin and quercetin, was studied in terms of the partition coefficients and the percentage of extraction. Rutin and quercetin showed better affinity to the EL-rich phase, evidencing that the use of the proposed ATPS may be a successful technique in the biotechnological industry for the separation of each flavonoid. 2020-01-01T00:00:00Z https://hdl.handle.net/10216/162953 Title: Water Purification Using Choline-Amino Acid Ionic Liquids: Removal of Amoxicillin Abstract: Antibiotics are the main active pharmaceutical ingredients (APIs) for the treatment and prevention (prophylaxis) of bacterial infections, for which they are essential for health preservation. However, depending on the target bacterial strain, an efficient treatment may imply weeks of continuous intake of antibiotics, whose unmetabolized fraction ends up in the wastewater system by human and animal excreta. The presence of these chemical compounds in wastewater is known to damage aquatic ecosystems and cause antibiotic resistance of pathogenic agents, which threatens the future application of these medicines. Aqueous two-phase systems (ATPSs), an emergent extraction technology for biomolecules such as proteins and vitamins, could provide more eco-friendly and cost-effective extractive alternatives given their nontoxicity and low energetic requirements. Moreover, choline-amino acid ([Ch][AA]) ionic liquids (also known as CAAILs or ChAAILs) are considered one of the greenest classes of ionic liquids due to their favorable biocompatibility, biodegradability, and ease of chemical synthesis. In this work, partition studies of amoxicillin were performed in three ATPSs containing dipotassium hydrogen phosphate (K2HPO4) and the CAAILs (cholinium l-alaninate, [Ch][Ala]; cholinium glycinate, [Ch][Gly]; and cholinium serinate, [Ch][Ser]) at 298.15 K and 0.1 MPa. To better characterize the extract and reduce errors in quantification, the effect of pH on the intensity and stability of the UV-vis spectra of amoxicillin was studied prior to the partition studies, and computational chemistry was used to validate the molecular structure of the synthesized ionic liquids. During experimental determinations, it was observed that the extraction of amoxicillin was favored by less polar ionic liquids, achieving maximum partition coefficients (K) and extraction efficiencies (E) of K = (16 +/- 6)10(1) and E / % = 97 +/- 2, respectively, for {[Ch][Gly] (1) + K2HPO4 (2) + Water (3)} in the longest tie-line. 2024-01-01T00:00:00Z https://hdl.handle.net/10216/163006 Title: Extraction of Salicylic Acid Using Sustainable ATPSs and Respective Immobilization as API-IL at Small Pilot Scale Abstract: Active pharmaceutical ingredients (APIs), a class of emerging pollutants present in residual waters, are often found in hospital effluents and are known to pose profound consequences to aquatic environments, such as the feminization of fish, for which finding sustainable extractive methodologies for these chemical species is a must. Aqueous two-phase systems (ATPSs) constitute a liquid-liquid extraction technique with low environmental impact that often results in the use of a salting-out agent, such as tripotassium citrate (K(3)Citrate), to separate two otherwise miscible phases. To increase the solubility of the extracted active pharmaceutical ingredients while preserving their specific properties, one can immobilize them as novel ionic liquids (ILs), and these complex chemical compounds are known as active pharmaceutical ingredients-ionic liquids (API-ILs). In this work, salicylic acid (Sa), a pharmaceutical component with wide medical and industrial applications, was extracted in ATPSs and immobilized as cholinium salicylate. Specifically, the systems {ethyl lactate (1) + Na(3)Citrate or K(3)Citrate or Na(2)Tartrate or NaKTartrate or Na(2)Succinate (2) + water (3)} were used at 298.15 K and 0.1 MPa. To advance large-scale application, the extraction studies were performed at small pilot scale using 500 g of ATPS and with the compositions of the shortest and longest tie-lines, having obtained the largest partition coefficient (K = (10 +/- 2) x 10(1)) and extraction efficiency (E/ % = 98.2 +/- 0.7%) for the longest tie-lines of the ATPSs based on K(3)Citrate and Na(2)Tartrate, respectively. Then, the ATPS based on K(3)Citrate was used to immobilize salicylic acid, and the structures of the synthesized ionic liquids (cholinium salicylate and cholinium citrate) were validated using FTIR measurements and IR predictions from computational chemistry. 2024-01-01T00:00:00Z https://hdl.handle.net/10216/162951 Title: Binary aqueous solutions of choline salts: Determination and modelling of liquid density (298.15 or 313.15 K) and Vapour Pressure Osmometry (313.15 K) Abstract: Salts composed of the cholinium cation (such as choline hydroxide and choline chloride) have become one of the main reactants for the synthesis of greener ionic liquids, but, for a proper description of the aqueous solutions of these strong electrolytes by thermodynamic modelling, reliable data on liquid density (rho) and vapour pressure (p) are needed, which are often unavailable. So, in this work, the liquid density (rho) of binary aqueous solutions of choline bicarbonate ([Ch][Bic]), choline (2R,3R)-bitartrate ([Ch][Bit]), choline chloride ([Ch]Cl), choline dihydrogen citrate ([Ch][H(2)Cit]) and choline hydroxide ([Ch]OH) were measured at 298.15 or 313.15 K and 0.1 MPa and correlated using second-degree polynomials with salt molality (m), obtaining determination coefficients (R-2) higher than 0.9974. Furthermore, the osmotic coefficients (phi) of these binaries were determined using vapour pressure osmometry (VPO), at 313.15 K and 0.1 MPa, being satisfactorily described by the Extended Pitzer Model of Archer, which yielded low values of standard deviation (3.58 < sigma(phi)10(3 )< 12.86). Then, the mean molal activity coefficients (gamma +/-) and excess Gibbs free energies (G(E)/RT) were calculated, following the order [Ch][H(2)Cit] > [Ch][Bit] > [Ch][Bic] > [Ch]OH > [Ch]Cl, which corresponds to the decreasing polarity of the choline salts and agrees with the empirical law of matching water affinities (LMWA). 2025-01-01T00:00:00Z https://hdl.handle.net/10216/162946 Title: Partition Studies of Resveratrol in Low-Impact ATPS for Food Supplementation Abstract: Antioxidant-rich food supplements can effectively address widespread nutritional deficiencies in the human diet and simultaneously reduce the concentration of reactive oxygen species (ROS) due to the free radical scavenging activity of antioxidants, minimizing inflammation and oxidative stress. Resveratrol (RVT) is a very important antioxidant which can be extracted from food industry byproducts such as grape skins, contributing to a more circular economy and reducing the environmental impact of the extraction processes. In this work, RVT was successfully extracted in the aqueous two-phase systems (ATPSs) {ethyl lactate (1) + Na(3)Citrate or K(3)Citrate or Na(2)Succinate or NaKTartrate (2) + water (3)} at 298.15 K and 0.1 MPa, which provided biocompatible and sustainable extractive media. The studied ATPS yielded partition coefficients (K) above unity, indicating a preference for the top phase (rich in ethyl lactate), which hints at a successful extraction of this phenolic compound. Larger tie-lines generally resulted in larger partition coefficients (K) and larger extraction efficiencies (E), favoring solute migration to the top phase. The most promising partition coefficients (K = 40 +/- 6 and 41 +/- 9) and extraction efficiencies (E/% = 98 +/- 1 and 95.0 +/- 0.6) were obtained for the longest tie-lines (TLL = 77.66 and 70.73 m%) for {ethyl lactate (1) + K(3)Citrate (2) + water (3)} and {ethyl lactate (1) + NaKTartrate (2) + water (3)}, respectively. Additionally, the effect of pH on the UV-vis absorbance spectrum of RVT was studied to minimize errors in solute quantification, resulting in low antioxidant mass losses (<5%). 2023-01-01T00:00:00Z https://hdl.handle.net/10216/174413 Title: Enhanced key performance indicators for energy performance contracts: A proposal for integrating indoor environmental quality evaluation 2026-05-24T00:00:00Z https://hdl.handle.net/10216/162990 Title: Novel Green Aqueous Two-Phase Systems (ATPSs) based on choline salts and application to the removal of pharmaceutical pollutants from water Abstract: Aqueous Two-Phase Systems (ATPSs) constitute extractive media with applicability for the removal of a wide range of solutes, such as antioxidants or pharmaceuticals, and can be designed in a non-toxic and environmentally friendly manner. Nevertheless, prior to their general use at large scale, their liquid-liquid equilibria (solubility curves and tie-line compositions) need to be thoroughly determined. In this work, 6 solubility curves were obtained for novel aqueous ternary systems containing choline salts (choline chloride, choline bicarbonate, choline (2R,3R)-bitartrate and choline di-hydrogen citrate) and either ethyl lactate (EL) or polyethylene glycol (PEG), at 298.15 K and 0.1 MPa. Moreover, 3 tie-line compositions were successfully determined for the system {ethyl lactate (1) + choline (2R,3R)-bitartrate (2) + water (3)}. Then, this novel ATPS was applied in the removal of three common pharmaceutical pollutants from aqueous media (acetaminophen, amoxicillin and salicylic acid). In these partition studies, salicylic acid and acetaminophen were effectively extracted to the top phase, with the highest partition coefficients (K = 9 +/- 2) being obtained for salicylic acid in the longest tie-line (length of 0.8816). Acetaminophen achieved the most promising results (K = 2.2 +/- 0.1) in the shortest tie-line (length of 0.6192). 2024-01-01T00:00:00Z https://hdl.handle.net/10216/162846 Title: Thermophysical Properties of Mixtures Containing Cholinium l-Alaninate and Water, Ethanol, or Propan-1-ol Abstract: Choline amino acid ionic liquids (CAAILs) provide a greeneralternativeto classical ionic liquids, such as the ones based on imidazoliumcations, since they can be obtained from natural sources with largerbiodegradability. Given that most industrial extractions are performedin either aqueous or alcoholic media, the thermophysical characterizationof binary mixtures containing these solvents is very important forprocess design. In this work, the influences of the mole fractionof ionic liquid and of temperature on the thermophysical propertiesof binary mixtures containing water, ethanol, or propan-1-ol and cholinium l-alaninate ([Ch][Ala]), a well-known CAAIL, were studied. Dynamicviscosity, shear stress, torque (T = 288.15 -308.15 K), electrical conductivity (T = 298.15 K),and density (T = 293.15, 298.15, 303.15 K) were measuredat 0.1 MPa, and the corresponding excess volumes were calculated andfitted to a Redlich-Kister (RK) equation. Moreover, the effectof temperature on density (T = 288.15 - 323.15K), dynamic viscosity (T = 288.15 - 323.15K), and refractive index (T = 288.15 - 343.15K) of the synthesized [Ch][Ala] was also evaluated and compared withliterature. Dynamic viscosities of the pure components were determinedand fitted using the Vogel-Fulcher-Tammann-Hesse(VFTH) equation. 2023-01-01T00:00:00Z https://hdl.handle.net/10216/162979 Title: Correlating Excess Volumes for Binary Mixtures of Green Solvents with the Help of Density Functional Theory Abstract: The development of green solvents is vital to decrease the environmental impact of separation processes by replacing their more hazardous equivalents, which often lack biodegradability, nontoxicity, and biocompatibility. Nevertheless, the application of green solvents in industry has been limited by the insufficiency of thermophysical data on their mixtures, which is due to low technological maturity and high cost of experimentation. So, there is a mounting interest in using computational chemistry as a predictive methodology. In this work, the liquid densities (rho) of the binary mixtures of ethyl lactate or cholinium iso-leucinate with water or ethanol were determined at 288.15, 293.15, 298.15, 303.15, or 308.15 K and 0.1 MPa. Then, the calculated excess volumes (V-E) were correlated with molar composition using three different methodologies: third-degree polynomials; Redlich-Kister expansions; and a novel approach based on computational chemistry (density functional theory). The standard deviation (sigma) of these approaches to experimental data showed that the novel methodology, which relied on calculating molar volumes by combining B3LYP/6-311++G(d) with the integral equation formalism polarizable continuum model, obtained a better description of the binaries (1.18 x 10(-8) < sigma/m(3)mol(-1) < 6.56 x 10(-8)) than third-degree polynomials (1.25 x 10(-7)< sigma/m(3)mol(-1) < 15.0x 10(-7)) and Redlich-Kister expansions (3.40 x 10(-8) < sigma/m(3)mol(-1) < 8.74 x 10(-8)). Moreover, this novel methodology was considered to decrease the number of adjustable parameters while, at the same time, providing a more concrete physical meaning to the parameters and enhanced accuracy and predictivity. 2024-01-01T00:00:00Z https://hdl.handle.net/10216/162965 Title: Measurement and modelling of liquid density (298.15 and 313.15 K) and vapour pressure osmometry (313.15 K) for binary aqueous solutions of organic salts Abstract: Due to the eco-friendliness of organic salts, they have been gradually replacing other electrolytes in different fields of chemistry. For example, they provide biocompatible salting -out agents for liquid-liquid extractions and earth -abundant materials for flow batteries. Nevertheless, reliable liquid density and vapour pressure data, which are paramount for a proper parameterisation of thermodynamic models, are often hard to find for aqueous solutions of organic salts, delaying the development of these technologies. In this work, the liquid density (p ) of five binary aqueous solutions of organic salts (disodium tartrate, sodium potassium tartrate, dipotassium tartrate, trisodium citrate and tripotassium citrate) were measured and correlated at 298.15 and 313.15 K and 0.1 MPa. In these assays, second-degree polynomials provided determination coefficients ( R 2 ) larger than 0.9982 in the correlation of liquid density with salt molality, for which a very accurate description of this property was accomplished. Moreover, vapour pressure osmometry (VPO) studies were carried out for these solutions at 313.15 K and 0.1 MPa. Then, the obtained osmotic coefficients ( o ) were successfully modelled using the Extended Pitzer Model of Archer, yielding standard deviations (c o ) lower than 8.61 & sdot; 10 -3 . Finally, the mean molal activity coefficients ( y +/- ) and excess Gibbs free energies ( G E /RT ) of the binary aqueous solutions of organic salts were effectively calculated, with potassium- and tartrate -based salts attaining significantly higher values than the ones composed of sodium and citrate, hinting at a more ideal solution behaviour of the former. 2024-01-01T00:00:00Z