Search results for "Renewable energy"
showing 10 items of 2318 documents
Electrooxidation of diesel fuel in alkaline electrolyte
2016
In recent decades the demand of energy has increased significantly.Providing more and more energy is an essential task of today’s energetic industry. In the last few years, addition to traditional methods of energy production, alternative energy sources have been developing fast.One of these sources is fuel cell, mainly due to their high efficiency. Generally fuel cells are powered by hydrogen. However, problems with the storage of hydrogen are the reason for the search of new fuels for fuel cells. Moreover, fuel cells can provide an additional/emergency electricity source in energy systems using combustion engines. So, it is important using the main fuel for powering the fuel cell. One of …
Developing Students Well-Being and Engagement in Higher Education during COVID-19—A Case Study of Web-Based Learning in Finland
2023
COVID-19 rapidly and extensively changed the normal everyday practices of societies, and there is no going back to the past. Universities also had to adapt and re-establish their normal routines, from policies to practices. In this article, we explore university students’ experiences of web-based learning, their well-being, and engagement during the pandemic. As a theoretical framework, we use the concept of the university student engagement inventory (USEI), which includes behavioral, cognitive, and emotional dimensions. The data were collected during the COVID-19 pandemic from university students (N = 35) via an online survey and analyzed using a thematic content analysis. According to th…
Protective and Educational Effects of Physical Activity Practice on Mental Health in Young Age during COVID-19 Lockdown
2022
Background: The restrictions imposed by the COVID-19 pandemic have modified the lifestyle of young people, worsening their mental health. Although some countries were allowed to practice outdoor physical activity (PA) in cases of lockdown, the PA level in the general population decreased. The current study aims to assess the differences in fear of COVID-19, anxiety, neuroticism, and general self-efficacy between university students who practiced PA during the second wave of lockdown and those who did not practice any PA. Methods: The sample consisted of 276 university students (176 females, 63.8%; mean age: 22.13, SD: ±3.94) who answered an online questionnaire detecting life habits …
IEA EBC Annex83 Positive Energy Districts
2021
At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive Energy Districts (PED) has accelerated in recent years. A common shared definition, as well as technological approaches or methodological issues related to PEDs are still unclear in this development and a global scientific discussion is needed. The International Energy Agency’s Energy in Buildings and Communities Programme (IEA EBC) Annex 83 is the main platform for this international scientific debate and research. This paper describes the challeng…
Pathways for the amplification of agroecology in African sustainable urban agriculture
2020
A growing awareness that highly intensified agricultural systems have made a substantial worldwide contribution to the worsening of the resilience capacity of natural ecosystems has, over the last twenty years, brought general attention to agroecological management models. This aspect is even more evident in industrial agriculture, which is based on the use of multiple chemical products derived from non-natural synthesis. In more developed countries, a new idea of ecology linked to agricultural production has been increasingly developed and, for this reason, there has been a greater diffusion of differentiated agricultural models taking into consideration the environmental impact of product…
An Economic Assessment of Micro-Scale Use of Renewable Energy Sources: Two Case Studies
2015
During recent times, renewable energy technologies have shown a relative fast growth in the global energy investment, global energy capacity and their integration within multiple sectors, particularly in the electricity sector. Renewable energy technologies have also experienced notorious declining costs on their manufacturing production. Nevertheless, while this growth is widely acknowledged, the share of renewables with respect total energy production has been moderate. Technological advancements in renewable energy have demonstrated the potential of renewables in energy generation and also that renewables can provide direct and indirect advantages over their counterparts. This thesis inv…
Applicability of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) bark extract as a precursor of rigid carbon foam and activated carbon
2023
Hybrid aspens have long attracted scientific interest, but the research on their use as feedstocks for chemical applications are still very limited. The bark biomass of the poplar species contains many valuable extractives that can be utilized as value-added products. This paper examines the applicability of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) bark extract as a precursor of rigid carbon foam and activated carbon. To explore this, the study considers 1) the basic chemical composition of the bark in terms of added value potential, 2) the basic chemical composition of the bark extract and the effect of its pretreatment on the extract composition, 3) the production of rigi…
Roczna wydajność instalacji PV zamontowanej na dachu budynku dydaktycznego Uniwersytetu Opolskiego
2018
Celem badań była analiza i ocena sprawności pracy instalacji fotowoltaicznej zamontowanej na dachu budynku dydaktycznego Uniwersytetu Opolskiego mieszczącego się przy ul. Kominka 6 w Opolu. Zakres pracy obejmował ocenę: energetyczną - uzysku energetycznego (ilość wyprodukowanego prądu a położenie geograficzne paneli fotowoltaicznych) i ekologiczną - redukcja emisji szkodliwych substancji niewyemitowanych do aerozolu atmosferycznego z powodu produkcji prądu przez instalację PV, a niedostarczonej przez elektrownię opalaną węglem. Badania wykazały dobry wynik uzysku energetycznego w ciągu roku - 5,30 MWh energii z tego systemu oraz znaczną redukcję emisji CO2 do atmosfery - 4,27 Mg/rok, co pot…
An intergenerational competency framework : Competencies for knowledge sustainability and start‐up development in the digital age
2022
In this study, we looked at the competencies and changes in the competency spectrum required for global start-ups in the digital age. Specifically, we explored intergenerational collaboration as an intervention in which experienced business-people from senior adult groups support young entrepreneurs. We conducted a Delphi study with 20 experts from different disciplines, considering the study context. The results of this study shed light on understanding the necessary competencies of entrepreneurs for intergenerationally supported start-up innovation by providing 27 competencies categorized as follows: intergenerational safety facilitation, cultural awareness, virtues for growth, effectual …
Decoupled control scheme of grid-connected split-source inverters
2017
Grid-connected power conversion systems for renewable energy sources must fulfill several requirements, e.g., the high efficiency, the reduced cost and complexity, and, quite often, the boost capabilities that is usually achieved using a front-end dc–dc boost converter before the inversion stage, leading to a two-stage architecture. Meanwhile, single-stage power conversion systems, which perform the boosting operation within the inversion one, offer some potential advantages, in terms of reducing the complexity and the volume of the whole system. Among several proposed options, the split-source inverter (SSI) has been recently proposed by Abdelhakim et al. as an alternative option with some…