Degradation of GaAs Solar Cells

Solární články na bázi arsenidu gallia patří mezi nejvýkonější typ dostupných solárních článků vůbec. Jejich výhodou je výborná odolnost vůči tepelnému a ionizujícímu záření, a proto se využívají zejména v náročných podmínkách. Tato disertační práce popisuje stav GaAs fotovoltaických článku vystavených vůči tepelnému namáhání, vysokému ochlazování, gama záření a ozáření širokospektrálním laserem. Vzorky byly zkoumány před, po a i během těchto procesů pomocí několika analytických a charakterizačních metod. Měření bylo zaměřeno na charakterizaci povrchu, optických a elektrických vlastností. Byly objeveny limity a nové chování tohoto typu článků, které jsou ovlivněny i tenkými ochrannými a antireflexními vrstvami.Gallium arsenide based solar cells are among the most powerful types of solar cells available. Their main advantage is excellent resistance to thermal and ionising radiation, and therefore they are used primarily in demanding conditions. This dissertation describes the state of GaAs photovoltaic cells exposed to thermal stress, high cooling, gamma radiation and broad-spectrum laser irradiation. The samples were examined before, after and during these processes using several analytical and characterisation methods. The measurements were focused on the characterisation of the surface, optical and electrical properties. Limits and new behaviour of this type of photovoltaic cells have been discovered, which are also affected by thin protective and anti-reflective layers.

Testing of SIP implementations in open source PBX's

Tato práce zkoumá a porovnává několik vybraných knihoven protokolu SIP, výkon, stabilitu, bezpečnost a vliv na jejich konfiguraci. Na začátku jsou stručně vyjmenovány hlavní funkce signalizačního protokolu. Následují kapitoly popisující testované ústředny a je teoreticky srovnáno několik stacků implementujících SIP protokol. V praktické části probíhalo měření na zátěžovém generátoru Spirent TestCenter C1, pomocí kterého se vykonávaly veškeré testy na ústřednách. Zmiňované SIP knihovny, PBX i operační systém, na kterém byly ústředny provozovány jsou open source.This diploma thesis examines and compares several selected libraries of SIP protocol, performance, stability, security and impact of their configuration. The main functions of the signalling protocol are briefly named at the beginning. The following chapters describe the tested PBXs and several stacks for SIP protocol are theoretically compared. The practical part deals with measurements conducted on the load generator Spirent TestCenter C1 which is used for all the performed tests on exchanges. All the mentioned SIP libraries, PBXs and the operating system on which the PBXs were running are open source software.

Overview of the Current State of Flexible Solar Panels and Photovoltaic Materials

The rapid growth and evolution of solar panel technology have been driven by continuous advancements in materials science. This review paper provides a comprehensive overview of the diverse range of materials employed in modern solar panels, elucidating their roles, properties, and contributions to overall performance. The discussion encompasses both traditional crystalline silicon-based panels and emerging thin-film technologies. A detailed examination of photovoltaic materials, including monocrystalline and polycrystalline silicon as well as alternative materials such as cadmium telluride (CdTe), copper indium gallium selenide (CIGS), and emerging perovskite solar cells, is presented. Furthermore, the impact of transparent conductive materials, encapsulation polymers, and antireflective coatings on solar panel efficiency and durability is explored. The review delves into the synergistic interplay between material properties, manufacturing processes, and environmental considerations. Through a comprehensiv

Current applications and challenges of the Internet of Things

The concept of the Internet of Things is capable of making a giant leap in the economy, including research in the field of computer science, network technologies, microelectronics and sensor technology. Combined with the technological developments of nanotechnology and robotics, IoT can play a central role in the industrial revolution by creating economic relations between machines and connecting the economy of people and machines, solving a number of problems that humanity is facing. All devices controlled via the Internet are elements of the Internet of things. The IoT has allowed various possibilities for all countries to improve life quality and the technological ideas for efficiency, productivity, security, and profit. An integrated security system is a giant step towards the improved economy. The concept of IoT plays a decisive role in the further development of the infocommunication industry. This is confirmed both by the position of the International Telecommunication Union (ITU) and the European Union on this issue, and by the inclusion of the Internet of Things in the list of breakthrough technologies in the United States, China and other countries. Thus, this article will go over the current state of the IoT as well as describe which devices and industries stand to benefit from the advantages it brings. Additionally, statistical data on the actual trends and investments into IoT across the world are also provided