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Java is one of the more recent programming languages that in runtime free applications from manual memory management by using automatic Garbage collector (GC) threads. Although, at the cost of stop-the-world pauses that pauses the whole application. Since the initial GC algorithms new collectors has been developed to improve the performance of Java applications. Still, memory related errors occurs and developers struggle to pick the correct GC for each specific case. Since the concept of microservices were established the benefits of using it over a monolith system has been brought to attention but there are still problems to solve, some associated to garbage collectors. In this study the performance of garbage collectors are evaluated and compared in a microservice environment. The measurements were conducted in a Java SpringBoot application using Docker and a docker compose file to simulate a microservice environment. The application outputted log files that were parsed into reports which were used as a basis for the analysis. The tests were conducted both with and without a database connection. Final evaluations show that one GC does not fit all application environments. ZGC and Shenandoah GC was proven to perform very good regarding lowering latency, although not being able to handle the a microservice environment as good as CMS. ZGC were not able to handle the database connection tests at all while CMS performed unexpectedly well. Finally, the study enlightens the importance of balancing between memory and hardware usage when choosing what GC to use for each specific case.

To gain observability in distributed systems, some telemetry generation and gathering must be implemented. This is especially important when systems have layers of dependencies on other microservices. One method for observability is called distributed tracing. Distributed tracing is the act of building causal event chains between microservices, which are called traces. Finding bottlenecks and dependencies within each call chain is possible with the traces. One framework for implementing distributed tracing is OpenTelemetry. The developer must determine design choices when deploying OpenTelemetry in a Kubernetes cluster. For example, OpenTelemetry provides a collector that collects spans, which are parts of a trace from microservices. These collectors can be deployed one on each node, called a daemonset. Or it can be deployed with one for each service, called sidecars. This study compared the performance impact of the sidecar and daemonset setup to that of having no OpenTelemetry implemented. The resources analyzed were CPU usage, network usage, and RAM usage. Tests were done in a permutation of 4 different scenarios. Experiments were run on 4 and 2 nodes, as well as a balanced and unbalanced service placement setup. The experiments were run in a cloud environment using Kubernetes. The tested system was an emulation of one of Nasdaq's systems based on real data from the company. The study concluded that having OpenTelemetry added overhead / increased resource usage in all cases. Having the daemonset setup, compared to no OpenTelemetry, increased CPU usage by 46.5 %, network usage by 18.25 %, and memory usage by 47.5 % on average. Sidecar did, in most cases, perform worse than the daemonset setup in most cases and resources, especially in RAM and CPU usage.

The development of precast concrete housing systems provides an opportunity to easily and inexpensively incorporate solar energy collection by casting collector tubes into the roof structure. A design is presented for a precast solar water heating system used to aid in meeting the space and domestic water heating loads of a single family residence. A three-dimensional transient collector model is developed to characterize the precast solar collector's performance throughout the day. The model describes the collector as a series of segments in the axial direction connected by a fluid flowing through an embedded tube. Each segment is represented by a two-dimensional solid model with top boundary conditions determined using a traditional flat plate solar collector model for convection and radiation from the collector cover plate. The precast collector is coupled to a series solar assisted heat pump system and used to meet the heating needs of the residence. The performance of the proposed system is compared to the performance of a typical air to air heat pump. The combined collector and heat pump model is solved using Matlab in conjunction with the finite element solver, Femlab. Using the system model, various non-dimensional design and operating parameters were analyzed to determine a set of near optimal design and operating values. The annual performance of the near optimal system was evaluated to determine the energy and cost savings for applications in Atlanta, GA and Chicago, IL. In addition, a life cycle cost study of the system was completed to determine the economic feasibility of the proposed system. The results of the annual study show that capturing solar energy using the precast collector and applying the energy through a solar assisted heat pump can reduce the electricity required for heating by more than 50% in regions with long heating seasons. The life cycle cost analysis shows that the energy savings justifies the increase in initial cost in locations with long heating seasons but that the system is not economically attractive in locations with shorter heating seasons. / Master of Science

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2018-04-03T18:34:14Z No. of bitstreams: 1 Osmar Borges Ruas.pdf: 4968457 bytes, checksum: f034d06ab41189910725d292527fd096 (MD5) / Made available in DSpace on 2018-04-03T18:34:14Z (GMT). No. of bitstreams: 1 Osmar Borges Ruas.pdf: 4968457 bytes, checksum: f034d06ab41189910725d292527fd096 (MD5) Previous issue date: 2017-10-16 / The delivery time is the time unit that determines the time needed to complete the project, which in external or internal conditions in organizations can cause deviations to the project deliveries. As a consequence, they can cause financial loss, excessive expenses, increased risks, communication failures, loss of quality among other problems. In some studies, alternatives are used to avoid or solve these problems in carrying out project management. As an alternative, this study uses about 100 million patents registrations deposited in the European Patent Office (EPO) Espacenet for potential solutions to deadline issues. The objective of this research is to identify the solutions for the delivery time of project management in the EPO base using the extraction of patents with the tool Patent2NET. With open source tooling, it allows for content analysis and bibliographic organization with mind maps. This research uses the qualitative method, with exploratory-descriptive character, with the analysis of secondary data. The correlation, similarity and frequencies of the words will be analyzed. Thus, contributions are offered to improve the understanding of these solutions found in four semantic classes, as well as the presentation of the techniques for constructing search expressions and the patents that can help in the solution of problems of the deadline and, therefore, to promote improvements in project management practices. / O prazo de entrega é a unidade temporal que determina o tempo necessário para concluir o projeto, que em condições externas ou internas em organizações podem causar desvios às entregas do projeto. Como consequência, podem trazer prejuízo financeiro, gastos excessivos, aumento de riscos, falhas de comunicação, perda de qualidade dentre outros problemas. Em alguns estudos, utilizam-se alternativas para evitar ou resolver esses problemas na realização do gerenciamento dos projetos. Como alternativa, este estudo utiliza cerca de 100 milhões de registros de patentes depositados no Espacenet da European Patent Office (EPO) para obter as potenciais soluções para problemas de prazo de entrega. O objetivo desta pesquisa é identificar as soluções de prazo de entrega em gerenciamento de projetos na base EPO utilizando a extração das patentes com a ferramenta Patent2NET. Com o manuseio de ferramentas open source são realizadas análises de conteúdo e a organização bibliográfica com mapas metais. Esta pesquisa utiliza o método qualitativo, com caráter exploratório-descritivo, com a análise de dados secundários. Serão analisados o correlacionamento, a similitude e as frequências das palavras. Dessa forma, são oferecidas contribuições para melhorar o entendimento dessas soluções encontradas em quatro classes semânticas, bem como a apresentação das técnicas para construção de expressões de busca e as patentes que podem ajudar na solução de problemas de prazo de entrega e, assim, promover melhorias nas práticas de gerenciamento de projetos.

The subject of the thesis is the use of solar thermal technology for the production of low-potential heat. The theoretical part is focus in the solar technology, variants of passive use of solar energy. Describes in detail the solar facades, it's classification in terms of basic criteria. Applications on the project forced ventilation in administrative buildings, installation of solar facade. The work also includes an experiment that deals with the thermal behavior of the air collector.

In this thesis I review the sufficient flow capacity of the safety valve against high-pressure heater thermal pressurization in high-pressure feedwater heater on nuclear power Dukovany. I present basic possible cases of thermal pressurization both a high node heater, and the extended pressure unit in case of closure all power heads to steam generators.

This thesis deals with the replacement of the lid gasket of the primary collector of the steam generator VVER 1000. Original sealing by nickel rings is replaced by kammprofile gasket with expanded graphite layers. The thesis compare the properties of both types of gaskets and the new and the original configuration of flange joint which have been calculated according to EN 1591. The results are compared and conclusions arising therefrom are presented. The work includes results of FEM analysis of the new configuration of the flange joint. There is also a description of the main components of the nuclear power plants VVER 1000 primary circuit in the introductory part which focused on the construction and operation of the steam generator and its primary collector.

The riparian zone is a changeable and species-rich habitat with important ecological functions that have long been affected by human activities such as hydropower and forestry. Rivers and their adjacent riparian zones also constitute a transport route for plant parts and seeds in a form of passive transport, called hydrochory, which can contribute to the establishment of plants or the preservation of diversity in the riparian zone. Theories such as "the river collector hypothesis" state that the diversity of plants increases with distance from the source of a river and this study aims to investigate a specific part of this theory, namely the effect of tributaries on the accumulation of plants in the riparian zone. Plant surveys have been carried out upstream and downstream of the outlets of several tributaries to Vindelälven (unregulated) and Umeälven (regulated) in Västerbotten County, Sweden, to compare these locations with each other. Species numbers and effective species numbers for upstream and downstream surveys were analysed using paired t-tests with the expectation that both species numbers and effective species numbers would be higher downstream of tributaries than upstream. The results showed no significant differences between the upstream and downstream inventories. When examining the data, there was an indication of a trend of higher species numbers and effective species numbers downstream of tributaries in the Umeälven, but further research is needed to investigate possible connections. The explanation of the effect of tributaries on the diversity of plants in the riparian zone may be more complicated than can be explained only by theories of the accumulation of plants from hydrochory. Alternatively, the effect from the tributaries is small in relation to the longitudinal build-up of plants that occurs in longer free-flowing stretches of the rivers, which may hide the effect of the tributaries. / Strandzonen är ett föränderligt och artrikt habitat med viktiga ekologiska funktioner som under lång tid har påverkats av mänskliga verksamheter som vattenkraft och skogsbruk. Älvar och dess angränsande strandzoner utgör även en transportsträcka för växtdelar och fröer i en form av passiv transport, benämnd hydrochori, som kan bidra till etableringen av växter eller bevarandet av mångfalden i strandzonen. Teorier som ”the river collector hypothesis” säger att mångfalden av växter ökar med avstånd från källan i en älv och den här studien har som mål att undersöka en specifik del av denna teori, nämligen vilken effekt biflöden har på ansamlingen av växter i strandzonen. Växtinventeringar har genomförts uppströms och nedströms om flera biflödens utlopp till Vindelälven (oreglerad) och Umeälven (reglerad) i Västerbottens län för att jämföra dessa lokaler med varandra. Artantal och effektivt artantal för uppströms- och nedströmsinventeringar analyserades med parade t-tester med förväntningen att både artantalet och det effektiva artantalet skulle vara större nedströms om biflöden än uppströms. Resultaten visade inga signifikanta skillnader mellan uppströms- och nedströmsinventeringarna. Vid granskning av data fanns en antydan till en trend med större artantal och effektivt artantal nedströms om biflöden i Umeälven men ytterligare undersökningar behövs för att utreda eventuella samband. Förklaringen till vilken effekt biflöden har på mångfalden av växter i strandzonen kan vara mer komplicerad än att det på egen hand kan förklaras med teorier om ansamling av växter från hydrochori. Alternativt är effekten från biflödena liten i relation till den longitudinella uppbyggnaden av växter som sker i längre fritt flödande sträckor av älvarna vilket skulle kunna dölja biflödenas effekt.

In Photovoltaic/Thermal (PVT) technology, both PV and solar thermal technology are integrated in the same module for simultaneous electricity and heat production. Research has shown that there are multiple benefits from integrating PVT collectors with a ground source heat pump (GSHP) system, since it allows for seasonal storage of thermal energy over the year. Furthermore, it leads to reduced operating temperatures for the PVT collectors which can increase efficiency and lifetime. The aim of this study is to present the electric and thermal performance of a PVT collector developed by Solhybrid i Småland AB, for different environmental and fluid inlet conditions that can occur when PVT collectors are connected to a GSHP system. Furthermore, the performance of this PVT design is evaluated with ASHRAE (Standard 93-2003), to allow for comparison with other PVT collector designs, with values on the overall heat loss coefficient (UL) and heat removal factor (FR). The modelling tool used for the study is the software COMSOL Multiphysics, which uses the finite element method to solve the partial differential equations in heat transfer and fluid flow problems. Based on the performance curves, the thermal and electrical efficiency of the collector is approximately 48.0-53.4% and 19.0-19.2% respectively at a reduced temperature of zero and irradiance levels of 800-1000 W/m2 for the mass flow rate of 0.026 kg/sm2 which was determined as most suitable to increase thermal performance. Furthermore, these results resulted in a heat removal factor (FR) and overall heat loss coefficient (UL) of 0.56-0.62 and 53.4-53.5 W/m2 K respectively. The results on the performance of the PVT collector in different weather conditions shows that the inlet water temperature can significantly affect operating time and the amount of thermal energy that can be extracted during the year, especially if the collector operates in a colder climate like Sweden. To assess the accuracy of the created model, future work includes experimental testing of the studied PVT collector. / En panel med kombinerad teknik av både solceller och termisk solfångare (PVT) kan producera både elektricitet och värme samtidigt. Forskning har visat att det kan finnas flera fördelar med att integrera PVT-paneler med ett bergvärmesystem, eftersom det mjliggör lagring av termisk energi över året. Dessutom leder ett sådant system till lägre drifttemperaturer som kan öka PVT-panelens effektivitet och livslängd. Syftet med studien är att presentera den elektriska och termiska prestandan av en PVT-panel utvecklat av Solhybrid i Småland AB för olika driftförhållanden som kan uppstå på grund av olika väderförhållanden och inlopps-temperaturer när panelerna är kopplade till ett bergvärmesystem. Vidare utvärderas prestandan för denna panel med ASHRAEmetoden (standard 93-2003), för att möjliggöra jämförelse med andra PVT-paneler. Modelleringsverktyget som använts i studien är mjukvaran COMSOL Multiphysics, som använder finita elementmetoden för att lösa partiella differentialekvationer i värmeöverförings-och flödesproblem. Baserat på prestandakurvorna som presenteras i resultatet, är den termiska och elektriska verkningsgraden approximativt 48.0-53.4% respektive 19.0-19.2% för en reducerad temperatur med värdet noll, en solstrålning mellan 800-1000 W/m2, för en massflödeshastighet på 0.026 kg/sm2 som beslutades som den mest lämpliga för att öka den termiska prestandan. Resultaten resulterade i en värmeavledningsfaktor (FR) och total värmeförlustkoefficient (UL) på 0.56-0.62 respektive 53.4-53.5 W/m2 K. Resultaten på PVT-panelens prestanda under olika väderförhållanden visar att vattnets inloppstemperatur kan påverka drifttiden och mängden termisk energi som kan extraheras under året avsevärt, speciellt i nordiskt klimat. För att bedöma korrektheten i resultaten och den skapade modellen rekommenderas experimentell testning av den studerade PVT-panelen.