Síntesi col·loidal de materials semiconductors ternaris nanoestructurats amb elevada absorció en el NIR

Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2024, Tutor: Albert Figuerola SilvestreNanoscience is an expansive and rapidly evolving field with diverse applications across multiple disciplines. Over the past 50 years, advancements in nanomaterials have significantly impacted areas such as physics, chemistry, biology, and engineering, leading to innovations in electronics, medicine, and environmental science. This project focuses on the development of ternary semiconductor Wittichenite (Cu3 BiS3 ) nanoparticles. These nanoparticles are a promising alternative to the currently dominant light-absorbing materials in thin-film solar cells, such as Copper Indium Gallium Selenide (CIGS), Copper Indium Selenide (CIS), and Cadmium Telluride (CdTe). The primary advantages of using Cu3 BiS3 lie in the abundance and lower toxicity of its constituent elements, copper and bismuth. Additionally, binary sulfides like Bi2S3 and Cu2S already demonstrate suitable bandgaps (ranging from 1.2 to 1.5 eV) and high absorption coefficients for the solar spectrum, encompassing visible, ultraviolet (UV), and infrared (IR) light . The ternary compound Cu3BiS3 is expected to exhibit enhanced properties, such as improved stability, homogeneity, an optimal bandgap, and efficient near-infrared (NIR) absorption, making it a viable candidate for next-generation solar cell materials. The synthesis method employed in this project follows a bottom-up approach, which is generally simpler and more straightforward than top-down methods for nanoparticle preparation. Specifically, colloidal thermal decomposition, a solution-based technique, is used due to its superior versatility and precise control over the nanoparticle size, shape, and phase. This method facilitates the production of high-quality nanoparticles that meet the desired criteria for advanced photovoltaic application

Щодо питання про форму трудового договору

Розкриваються особливості форм трудового договору, дається її визначення, підкреслюється важливість письмової форми трудового договору, її перевага перед усною. Аналізуються точки зору провідних науковців Європи в галузі трудового права.Расскрываются особенности форм трудового договора, дается ее определение, подчеркивается важность письменной формы трудового договора, ее преимущество перед устной, анализируются точки зрения ведущих ученых Европы в отрасли трудо­вого права.The author has researched the specific features of the contract labour, has given its defini­tion, pointed out the importance of the written form of this contract, this type of the contract has been analyzed from the point of view of the leading scientists of Europe in the field of labour law

Solar Photovoltaics in District Heating and Cooling Sector: An Overview

With the prevalent energy scenario and climate changes, decarbonising energy sector has become the need of the hour. An environmentally friendly way is the utilisation of solar energy, which mainly involves the deployment of photovoltaic (PV) panels and/or solar thermal collectors. Unlike electricity generation, the application of photovoltaics in the district heating & cooling (DHC) sector is relatively new. Also, this energy route is not fully explored by scientific community. This paper aims to provide an overview of the photovoltaic application in district heating & cooling sector. At first, the utilisation of solar energy in the DHC sector is briefly described. Then relevant literature in PVDHC is reviewed. It was understood that different topologies are in place for solar energy integration in the DHC system. These topologies vary in terms of the chosen technology, energy storage, system configuration (centralized/distributed) and components. It was found that the research database on the studied topic needs enhancement, with a special focus on PV cooling. From the literature survey, it is deduced that solar PV could play a significant role in future DHC systems due to the possible combination with other energy sources or electric grid or storage technology. Based on the SWOT analysis, it is concluded that there is an enormous opportunity for PV integration in the DHC sector. However, adequate techno-economic support is required to overcome threats and weaknesses. This study is expected to be beneficial to policymakers, researchers and other stakeholders in district energy market

Performance evaluation of joint cooling and information transmission for on-board communications

Progress of hardware components provides the growth of computer performance ap-proximately every decade. Along with increasing complexity of computer components, there is also the trend to miniaturization. All these imply the need in new ways of com-ponents interconnections with efficient interface communications inside modern com-puters. On the other hand, the progress of hardware components and miniaturization result to the rise of heat release. New ways of cooling are constantly developing for modern computers, including laptops, tablets and smartphones. However, not all of them are efficient enough. Having communications and cooling systems separately often makes it impossible to miniaturize a computer device. In order to succeed in this direction, the combination of both systems is needed. The new system should not only allow the hybrid design, but also provide efficient cooling and information transmission. In this thesis, the statement of efficient joint cooling and information transmission is described. System design, the choice of necessary materials, properties of signal propa-gation and performance evaluation of the results for cooling and data transfer are pro-vided in the thesis. It is shown that the terahertz frequency range is the most suitable for the information exchange between hardware components as it could provide extremely high data rates. However, it requires specific conditions for proper performance including non-absorbing materials. A system based on heat pipes is proposed. The heat pipes, working as a cooling system as well as a waveguide, have cooling medium inside and metal casing. Cooling medium and metal casing should satisfy both cooling and transmission requirements. The best choice of cooling medium is a refrigerant, especially isobutane, as it does not have ab-sorption and provides the best cooling properties. The best casing is copper as it ensures good reflectivity for the propagated signal and thermal conductivity for the heat trans-fer. The results of the cooling evaluation are reached through MATLAB software calcula-tions. Transmission performance is calculated in the COMSOL Multiphysics simulation software. The results prove that the materials are chosen right and the system is efficient for the use in modern computers

Towards Forming Optimal Communication Network for Effective Power System Restoration

Restoration of modern interdependent Information and Communication Technology (ICT) and power networks relies on preplanned and reactive strategies to consider simultaneous communication and power system recovery. This paper addresses the problem of finding and energizing a proper communication network connecting the distributed power grid assets in the restoration process, assuming a probability of infeasibility of recovering each communication node. The proper network has the minimum size, meets the communication requirements of power system recovery, and guarantees robustness against ICT nodes not being recoverable during restoration. The problem is formulated as a multi-objective optimization problem and solved using the genetic algorithm to find the optimal subgraph that ensures enough node-disjoint paths between the communicating power grid assets. Simulation results for the restoration strategy of the communication network associated with a power network are provided and discussed. The results show that networks’ ability to mitigate the adverse consequences of node failures can be significantly improved by incorporating just a few additional nodes and links while keeping the ICT network compact and feasible for restoration

Renewable Energy Community’s Barriers and Impact on Centralised Energy Production

Major changes are taking place in the energy sector. In order to achieve climate neutrality, it is crucial to increase energy production from renewable energy sources. One way to accomplish this is to establish energy communities and cooperatives, which require optimal development and expansion solutions. Energy cooperatives are, by definition, community projects whose primary goal is to generate electricity and heat for their own use as well as for sale and distribution. The main reasons for establishing such communities are to reduce costs and the negative impact on the environment, as well as to democratise and decentralise production, reducing reliance on larger producers. This kind of collaborative effort also allows people who lack the necessary funds and knowledge to participate in the production of renewable energy. The goal of energy communities is to use energy produced primarily from renewable energy sources; the easiest way to do this is to use solar panels, but there are also other options. Although the European Union has launched several programmes to increase the number of energy communities, there are several barriers that prevent them from being established. In the conditions where energy communities are connected to largescale energy systems, it is also important to assess how energy communities affect centralised energy production and overall energy efficiency. This study provides a thorough analysis of the barriers to establishing energy communities as well as their impact on centralised energy production and overall energy production efficiency

Planning of district heating regions in Estonia

It is quite evident that district heating networks will continue to be developed in order to complete their transition towards the 4th generation district heating by decreasing heat losses, increasing the share of renewable and waste heat sources, and integrating energy storage units and smart operating solutions. The significance of district heating in Estonia is very high, and developing this sector is very important for achieving climate and energy targets set by Estonia. Consumers play important role in the transition process, and for the purpose of informing and educating consumers, a district heating promo app has been implemented at the national level. One of the app’s modules shows consumers the energy mix that will be required to supply heat via district heating in the future, with all of the planned changes and different district heating regions taken into account. Measures and goals proposed in the Estonian National Development Plan of the Energy Sector until 2030, as well as all available heating strategies from various district heating regions have also been considered. The algorithm of the methodology takes into account possible changes in heating demand caused by increased energy efficiency of the building sector, heat loss reduction due to renovation of existing DH networks and possible reduction of DH temperature, as well as increase in the share of renewable energy sources and its impact on primary energy consumption and CO2 emissions in DH area.  Scenarios show which fuel/primary energy mix is expected to be used for heat generation in the future (the data is given for each district heating region), as well as the amount of CO2 emissions. Several typical case studies are also provided

Digital Vigilance: the Ethics of Network Communication and the Limits of Civilian Control

The article analyzes such a modern form of network civic activity as “digital vigilance”. It proves that digital vigilance as a challenge to digitalization is an interdisciplinary problem, it requires both conceptualization and serious empirical research. This study addresses issues of relations between the state and citizens in a networked, digital society, especially the formation of network ethics and analysis of the perception of citizens of the digital public space