Browsing by Issue Date, starting with "2025-09"
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- Effect of nickel on the mechanical properties of spray-formed Al-15Si-2Cu alloy at elevated temperaturesPublication . Goudar, Dayanand M.; Alavandi, Mehabubsubahani R.; Bhat, Subraya Krishna; Bommenahalli, Raghukumar; Kurahatti, Rajashekar V.; Pinto, Deesy G.; Raju, K.; Pinto, Deesyat different temperatures was examined and evaluated with that of the as-cast (AC) alloy. The microstructure of SF alloys revealed uniformly distributed spherical shaped primary silicon and eutectic silicon phases along with fine Ni and Cu intermetallic particles dispersed throughout the equiaxed Al matrix. The microstructure of AC alloys consisted of coarse primary Si, flake-type eutectic phase, Cu-rich intermetallics with a complex branched morphology and a network of short strips. The mechanical properties of the alloys were assessed at temperatures of 30◦C, 100◦C, 200◦C and 300◦C. The SF alloys exhibited higher hardness than AC alloys at all temperatures with a maximum increase of 74 % at 30◦C. The hardness of alloys showed a decreasing trend with increasing temperature. The mechanical strength of SF alloys was higher than that of the AC alloys across the entire temperature range from 30◦C to 300◦C with a decrease in ultimate tensile strength (UTS) by 4–6 % at 250◦C. The SF alloys demonstrated a significant increase in UTS (25 % at 30◦C and 40 % at 300◦C) compared to the AC alloys. The Al-15Si-2Cu-2Ni alloy showed highest increase (14.3–18.6 %) and Al-15Si-2Cu-6Ni alloy showed the lowest increase (10.5 % to 14 %) in percent elongation between 30◦C and 300◦C.
- 2024 U.S. presidential elections: an event study for U.S. and non-U.S. fossil fuel and renewable listed firmsPublication . Martins, António Miguel; Albuquerque, Bruno; Sardinha, Luís; Moutinho, Nuno; Martins, António; Albuquerque, Bruno; Sardinha, LuisThis study examines the short-term market effect of Donald Trump’ victory in the 2024 US presidential election on largest US and non-US listed worldwide fuel fossil and renewable firms. Employing an event study meth odology, we observe a negative and statistically significant stock price reaction for worldwide renewable listed firms. An analysis by economic zones reveals the existence of negative abnormal returns for renewable energy firms in the US, Europe, India and in the rest of the world. In the case of China, abnormal returns are not sta tistically significant. With respect to worldwide fossil fuel listed firms, abnormal returns are generally not sta tistically significant. However, regarding US firms, we observe positive and statistically significant abnormal returns. These abnormal returns are explained by the change of US energy policy (pro-oil and gas policy) and the expected cut in subsidies and lower profitability of investments in green energies. Finally, our study provide insight into which firm-specific characteristics emerge as value drives around US presidential elections. The results show that despite the change in environmental policy in the US, favourable to fossil energy, the stock markets reward firms with high environmental ratings. Overall, our results indicate that 2024 US presidential election, for implying a change in US energy policy, has relevant policy implications for energy listed firms.
- Containerizing and evaluating the WRF model for cloud-based HPCPublication . Gouveia, Diogo Manuel Sales; Baras, Karolina; Vieira, Rui Ricardo AlmeidaNumerical models are mathematical representations that solve algebraic or differential equations to simulate phenomena across time and space. Some models, such as the Weather Research and Forecasting (WRF) model, are applied to weather prediction, providing valuable information to individuals, companies, institutions, and governments on potential future events. However, the WRF model can become highly computationally demanding, requiring increasingly power ful hardware resources with the increase of the resolutions and complexity of the simulations. High-Performance Computing (HPC) allows users to leverage powerful instances tailored to their needs, providing the necessary hardware resources for running complex WRF simulations. Mean while, cloud computing presents an enticing option for computationally demanding programs, offering advantages such as economies of scale, high reliability, and availability. On the software side, compiling, configuring, and installing multiple libraries are essential to exploit WRF’s po tential, which can be an arduous task. This study explores a cloud-enabled approach using pre configured Docker images and compares it to on-premises, HPC, and cloud solutions. We also analyze whether cloud computing is economically and performance-wise viable, using a compa rable base architecture across multiple cloud providers, and assess if the convenience of Docker meets the requirements despite potential overhead.
- Between kisses and bytes: cyber dating abuse and internet use in emerging adulthoodPublication . Saial, Ana Cristina; Portugal, Alda; Gouveia, Élvio Rúbio; Nascimento, Paulo; Satar, Muhammad; Relvas, Ana Paula; Portugal, Alda; Gouveia, Élvio RúbioAbstract Emerging adults use the internet to connect with intimate partners, which can promote closeness but also increase vulnerability to abusive behavior, such as cyber dating abuse (CDA). In this study, we explored the use of the internet and information and communication technologies (ICT) and determined the prevalence of CDA among 105 emerging adults, with an average age of 23.2 years (SD = 3.65). Through an online cross-sectional study, our results indicate that emerging adults spend an average of 6.67 h a day online (SD = 3.34), with 37.6% communicating with their partner for more than 5 h daily via ICT. A high prevalence of CDA was observed: 62.9% victimization and 74.3% perpetration, with an emphasis on controlling behaviors. This study explores the relationship between problematic internet use (PIU) and CDA and highlights the normalization of CDA behaviours.