Abstract
The literature on the isothermal model gas flow is extensive, but the effect of temperature variation on the hydraulic characteristics has been rarely addressed. Additionally, the impact of hydrogen blending on the thermal condition of NG pipelines is also an emergent topic that requires new approaches to the gas flow problem formulation and resolution. In this paper, a model for the gas flow problem was developed to optimise the operation of natural gas distribution networks with hydrogen injection while maintaining pressure, gas flows, and gas quality indexes within admissible limits. The goal is to maximise the injection of hydrogen and investigate the influences of thermal variations in the gas blending. Also, this model enables the calculation of the maximum permitted volume of hydrogen in the network, quantifying the total savings in natural gas usage and carbon dioxide emissions in different temperature conditions.

Abstract
Renewable energy and electric mobility are crucial in addressing current environmental and energy challenges. As the number of electric vehicles increases, more charging infrastructure connected to the electricity distribution network is required. This paper proposes an approach to sizing a fast charging station for electric vehicles. This challenge is addressed by including a battery energy storage system (BESS) and considering the self-production from a renewable energy source (solar energy) in the system. The aim is to minimise the total energy costs, avoid future infrastructure upgrades, and take advantage of the integration of renewable energy resources. The methodology used is a Biased Random Key Genetic Algorithm (BRKGA) based meta-heuristic. Computational experiments were conducted for the sizing of a charging station under four different scenarios that minimise energy costs. The results show that incorporating BESS can lead to a significant reduction in the costs related to the purchase of energy from the grid. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

Abstract
While place attachment has been a hot research topic in tourism, place meanings generally have received less attention from researchers. By bridging environmental psychology to the context of tourism, this research employs schema theory to explore how the home environment influences place meanings perceived in foreign destinations by tourists belonging to the same cultural group, i.e., Chinese and Macau outbound tourists in Europe. Semi-structured interviews were conducted, and the findings show that there is much overlap in both groups' place meanings regarding Europe as they are culturally Chinese. Nonetheless, the Portuguese symbolic settings of their home environment are profoundly integrated in the Macau interviewees' autobiographical memories and self-identity, which turns them into "vicarious insiders" of Portugal prior to their actual visits, thus rendering Portugal a specifically meaningful destination. This study makes theoretical contributions to the tourism place literature and provides practical implications regarding meaning marketing for destination management organizations.

Abstract
The growing demand for sustainable and environment-friendly energy sources resulted in extensive research in the field of renewable energy. Biomass, derived from organic materials such as agricultural waste, forestry products, and wastewater treatment plant (WWTP) sludge, holds great potential as a renewable energy resource that can reduce greenhouse gas emissions and offer sustainable solutions for energy production. This study focused on diverse biomass materials, including sludge from WWTPs, forest biomass, swine waste, cork powder, and biochar. Chemical and physicochemical characterizations were performed to understand their energy potential, highlighting their elemental composition, proximate analysis, and calorific values. Results showed that different biomasses have varying energy content, with biochar and cork powder emerging as high-energy materials with net heating values of 32.56 MJ/kg and 25.73 MJ/kg, respectively. WWTP sludge also demonstrated considerable potential with net heating values of around 14.87 MJ/kg to 17.44 MJ/kg. The relationships between biomass compositions and their heating values were explored, indicating the significance of low nitrogen and sulphur content and favourable carbon, hydrogen, and moisture balances for energy production. Additionally, this study looked into the possibility of mixing different biomasses to optimize their use and overcome limitations like high ash and moisture contents. Mixtures, such as 75% Santo Emiliao WWTP Sludge + 25% Biochar, showed impressive net heating values of approximately 21.032 MJ/kg and demonstrated reduced emissions during combustion. The study's findings contribute to renewable energy research, offering insights into efficient and sustainable energy production processes and emphasizing the environmental benefits of biomass energy sources with low nitrogen and sulphur content.

Abstract
One of the biggest obstacles when it comes to the electrification of the vehicle fleet is the charging time of an electric vehicle (EV), which means that users of these vehicles, when they need to charge their car, always look for fast charging stations. This is the charging method that has the shortest duration. In the coming years, an increase in the proliferation of electric vehicles will lead to a greater demand for electricity, which in turn will put the distribution network to the test. Since the number of non-linear loads increases day by day, putting the distribution network under increasing stress, it is wise to study the effects of the high penetration of electric vehicles (EV) on the power quality of the network. This paper aims to study the impact of charging EV on the quality of energy in the distribution network. First, an analysis of the harmonics and electronics (non-linear loads) associated with EV chargers will be done. Then, a simulation will be performed on the IEEE 33 network using the Matlab/Simulink simulation software. Finally, a comparison will be made of the results obtained in the simulation and possible ways of mitigating the harmonics that non-linear loads inject into the electricity distribution network. Keywords. Electrical Vehicle (EV), Harmonic Analysis, Matlab/Simulink, EV DC Fast Charger, Non-Linear Loads.

Abstract
Accurate dynamics modelling of Unmanned Under-water Vehicles (UUV s) is critical for optimizing mission planning, minimizing collision risks, and ensuring the successful execution of tasks in diverse underwater environments. This paper presents a structured approach to estimating the hydrodynamic coeffi-cients of UUV s. Initially, it follows a detailed methodology for estimating hydrodynamic coefficients using simple geometries, a sphere and a spheroid, using the Computational Fluid Dy-namics (CFD) software OpenFoam, and comparing the results to analytical solutions, enabling the validation of the simulations approach. Following this, the paper provides an in-depth analysis of the damping and added mass coefficients for the Raya UUV, offering valuable insights into its hydrodynamic behaviour. © 2024 IEEE.