847 resultados para Interconnected microgrids
Resumo:
Systemic innovation has emerged as an important topic due to the interconnected technological and sociotechnical change of our current complex world. This study approaches the phenomenon from an organizing perspective, by analyzing the various actors, collaborative activities and resources available in innovation systems. It presents knowledge production for innovation and discusses the organizational challenges of shared innovation activities from a dynamic perspective. Knowledge, interaction, and organizational interdependencies are seen as the core elements of organizing for systemic innovations. This dissertation is divided into two parts. The first part introduces the focus of the study and the relevant literature and summarizes conclusions. The second part includes seven publications, each reporting on an important aspect of the phenomenon studied. Each of the in-depth single-case studies takes a distinct and complementary systems approach to innovation activities – linking the refining of knowledge to the enabling of organizations to participate in shared innovation processes. These aspects are summarized as theoretical and practical implications for recognizing innovation opportunities and turning ideas into innovations by means of using information and organizing activities in an efficient manner. Through its investigation of the existing literature and empirical case studies, this study makes three main contributions. First, it describes the challenges inherent in utilizing information and transforming it into innovation knowledge. Secondly, it presents the role of interaction and organizational interdependencies in innovation activities from various novel perspectives. Third, it highlights the interconnection between innovations and organizations, and the related path dependency and anticipatory aspects in innovation activities. In general, the thesis adds to our knowledge of how different aspects of systems form innovations through interaction and organizational interdependencies. It highlights the continuous need to redefine information and adjust organizations and networks based on ongoing activities – stressing the emergent, systemic nature of innovation.
Resumo:
Effective control and limiting of carbon dioxide (CO₂) emissions in energy production are major challenges of science today. Current research activities include the development of new low-cost carbon capture technologies, and among the proposed concepts, chemical combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) have attracted significant attention allowing intrinsic separation of pure CO₂ from a hydrocarbon fuel combustion process with a comparatively small energy penalty. Both CLC and CLOU utilize the well-established fluidized bed technology, but several technical challenges need to be overcome in order to commercialize the processes. Therefore, development of proper modelling and simulation tools is essential for the design, optimization, and scale-up of chemical looping-based combustion systems. The main objective of this work was to analyze the technological feasibility of CLC and CLOU processes at different scales using a computational modelling approach. A onedimensional fluidized bed model frame was constructed and applied for simulations of CLC and CLOU systems consisting of interconnected fluidized bed reactors. The model is based on the conservation of mass and energy, and semi-empirical correlations are used to describe the hydrodynamics, chemical reactions, and transfer of heat in the reactors. Another objective was to evaluate the viability of chemical looping-based energy production, and a flow sheet model representing a CLC-integrated steam power plant was developed. The 1D model frame was succesfully validated based on the operation of a 150 kWth laboratory-sized CLC unit fed by methane. By following certain scale-up criteria, a conceptual design for a CLC reactor system at a pre-commercial scale of 100 MWth was created, after which the validated model was used to predict the performance of the system. As a result, further understanding of the parameters affecting the operation of a large-scale CLC process was acquired, which will be useful for the practical design work in the future. The integration of the reactor system and steam turbine cycle for power production was studied resulting in a suggested plant layout including a CLC boiler system, a simple heat recovery setup, and an integrated steam cycle with a three pressure level steam turbine. Possible operational regions of a CLOU reactor system fed by bituminous coal were determined via mass, energy, and exergy balance analysis. Finally, the 1D fluidized bed model was modified suitable for CLOU, and the performance of a hypothetical 500 MWth CLOU fuel reactor was evaluated by extensive case simulations.
Resumo:
Vero cells, a cell line established from the kidney of the African green monkey (Cercopithecus aethiops), were cultured in F-10 Ham medium supplemented with 10% fetal calf serum at 37°C on membranes of poly(L-lactic acid) (PLLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and their blends in different proportions (100/0, 60/40, 50/50, 40/60, and 0/100). The present study evaluated morphology of cells grown on different polymeric substrates after 24 h of culture by scanning electron microscopy. Cell adhesion was also analyzed after 2 h of inoculation. For cell growth evaluation, the cells were maintained in culture for 48, 120, 240, and 360 h. For cytochemical study, the cells were cultured for 120 or 240 h, fixed, processed for histological analysis, and stained with Toluidine blue, pH 4.0, and Xylidine ponceau, pH 2.5. Our results showed that cell adhesion was better when 60/40 and 50/50 blends were used although cells were able to grow and proliferate on all blends tested. When using PLLA/PHBV (50/50) slightly flattened cells were observed on porous and smooth areas. PLLA/PHBV (40/60) blends presented flattened cells on smooth areas. PLLA/PHBV (0/100), which presented no pores, also supported spreading cells interconnected by thin filaments. Histological sections showed that cells grew as a confluent monolayer on different substrates. Cytochemical analysis showed basophilic cells, indicating a large amount of RNA and proteins. Hence, we detected changes in cell morphology induced by alterations in blend proportions. This suggests that the cells changed their differentiation pattern when on various PLLA/PHBV blend surfaces.
Resumo:
This basic research focuses on the ethos of health and the human being's becoming in health. The theoretical perspective consists of the caring tradition within caring science developed at Åbo Akademy University. The aim of the present doctoral thesis is to uncover a new understanding as well as to deepen and attain a more nuanced understanding of the ethos of health, the essence of health, by penetrating to the core of what gives the human being the strength for experiencing a becoming in health. The research questions are as follows: l) What is the human being's source of strength? and 2) What reveals the source of strength so that the human being can perceive it and dedicate its strength in order to experience a becoming in health? The primary methodology used in the dissertation is hermeneutical. The material consists of the work Kärlekens gerningar by Kierkegaard, texts from focused interviews with respondents who have lived through severe personal suffering, as well as the book Det bländande mörkret by Wikström. These texts are interpreted through hermeneutical reading. The new horizon of understanding that emerges is reflected towards Eriksson's caritative theory, towards prior research within the tradition of caring science at Åbo Akademy University and towards previous national and international studies within this field. The new understanding shows that the human being's source of strength is love, the essence and origin of life. The substance of health is love, which, through the trinity of faith, hope and love, also makes possible the existence of the source of strength. Love has a deeper dignity than faith and hope, is connected with eternity and is the uniting link between temporality and eternity. The human being's inner longing entails an ontological attraction towards the source of strength. This source of strength is hidden, which provides and maintains its force, like a mystery connected with the darkness of suffering that hides the secret representing the source of strength, life's mystery, bu t w hi ch is revealed in both the darkness of suffering and in the light of joy. The dedication of strength requires freedom, willingness and courage to see the light, despite awareness of shame and guilt. Creative acts liberate the human being for the dedication of strength, which is preceded by a holy presence where, in solitude, the human being makes sacrifices for the sake of his or her human smallness and weakness, and allows himself or herself to be enclosed by the darkness of suffering to discover the light from the source. This entails being enraptured in a quiet "doing" in order to experience the beauty that bears witness to the holy which creates unity. The source of strength is revealed through beauty. The ethos of the human being and the ethos of health have the same fundamental substance, whilst the ethos of life possesses the deepest dimension and concerns the mysterious and infinite eternity. The ethos of life, eternity, which is a wellspring of strength, is not in itself strength-giving unless it is allied with love. Health can be understood in the light of life, of which death is an inevitable part. Life itself constitutes and creates the source which, through its alliance with eternity' s primordial wellspring of strength, generates strength from which the human being's source of strength, love, receives its eternal fervour. The human being is fundamentally interconnected with an abstract other, the first love, a universal wellspring of strength. Through Communion with this abstract other a dedication of the strength to experience a becoming in health becomes possible. Love for one's neighbour is the fundamental substance in the movement of becoming in health. Becoming in health presupposes a simultaneous movement in which the human being practices the human calling through ethos. As one loves one's neighbour through actions the still forces of eternity are in motion. When life emerges in the foreground and becomes the home of the human being, a dedication of the power of love is possible. Life itself determines the human being's becoming in health. A humble fundamental attitude towards life constitutes the basis for a continuous dedication of vitality from this source.
Resumo:
This study is a literature review on laser scribing in monolithically interconnected thin-film PV modules, focusing on efficiency of modules based on absorber materials CIGS, CdTe and a-Si. In thin-film PV module manufacturing scribing is used to interconnect individual cells monolithically by P1, P2 and P3 scribes. Laser scribing has several advantages compared to mechanical scribing for this purpose. However, laser scribing of thin-films can be a challenging process and may induce efficiency reducing defects. Some of these defects can be avoided by improving optimisation or processing methods.
Resumo:
The main objective of the study was to define the methodology for assessing the limits for application island grids instead of interconnecting with existing grid infrastructure. The model for simulation of grid extension distance and levelised cost of electricity has been developed and validated by the case study in Finland. Thereafter, sensitivities of the application limits were examined with the respect to operational environment, load conditions, supply security and geographical location. Finally, recommendations for the small-scale rural electrification projects in the market economy environment have been proposed.
Resumo:
The television and the ways it has invited the audience to take part have been changing during the last decade. Today’s interaction, or rather participation, comes from multiplatform formats, such as TV spectacles that combine TV and web platforms in order to create a wider TV experience. Multiplatform phenomena have spread television consumption and traditional coffee table discussions to several different devices and environments. Television has become a part of the bigger puzzle of interconnected devices that operates on several platforms instead of just one. This thesis examines the Finnish television (2004–2014) through the notion of audience participation and introduces the technical, thematic, and social linkages as three different phases, interactive, participatory, social, and their most characteristic features in terms of audience participation. The aim of the study is also to focus on the idea of a possible change by addressing the possible and subtler variations that have taken place through the concept of digital television. Firstly, Finnish television history has gone through numerous trials, exploring the interactive potential of television formats. Finnish SMS-based iTV had its golden era around 2005, when nearly 50% of the television formats were to some extent interactive. Nowadays, interactive television formats have vanished due to their negative reputation and this important part of recent history is mainly been neglected in the academic scope. The dissertation focuses also on the present situation and the ways television content invites the audience to take part. “TV meets the Internet” is a global expression that characterises digital TV, and the use of the Web combined with television content is also examined. Also the linkages between television and social media are identified. Since television can nowadays be described multifaceted, the research approaches are also versatile. The research is based on qualitative content analysis, media observation, and Internet inquiry. The research material also varies. It consists of primary data: taped iTV formats, website material, and social media traces both from Twitter and Facebook and secondary data: discussion forums, observations from the media and Internet inquiry data. To sum up the results, the iTV phase represented, through its content, a new possibility for audiences to take part in a TV show (through gameful and textual features) in real-time. In participatory phase, the most characteristic features from TV-related content view, is the fact that online platform(s) were used to immerse the audience with additional material and, due to this, to extend the TV watching enjoyment beyond the actual broadcast. During the Social (media) phase, both of these features, real-timeness, and extended enjoyment through additional material, are combined and Facebook & Twitter, for example, are used to immerse people in live events (in real-time) via broadcast-related tweets and extra-material offered on a Facebook page. This thesis fills in the gap in Finnish television research by examining the rapid changes taken place on the field within the last ten years. The main results is that the development of Finnish digital television has been much more diverse and subtle than has been anticipated by following only the news, media, and contemporary discourses on the subject of television. The results will benefit both practitioners and academics by identifying the recent history of Finnish television.
Resumo:
The present Master’s thesis presents theoretical description of the extraodinary behavior of the confined Indium nanoparticles. Superconducting properties of nanoparticles and nanocomposites are extensively reviewed. Special attention has been paid to phase fluctuation, shell and disordered effects. The experimental data has been obtained and provided by Dmitry Shamshur from Ioffe Physical Technical Institute. The investigated material represents a highly ordered system of silicate spheres filled with indium metal, where the In nanoparticles are interconnected between each other. Bulk indium is a superconductor with crititcal superconducting temperature Tc0 = 3:41 K. But indium nanoparticles exhibit different behavior, the critical temperature rise by approximately 20% up to 4.15 K. As well as transition of the indium particles to type-II superconductivity with high critical magnetic fields. Such diversity is explained by finite size effects which originate from nanosize of the samples.
Resumo:
Sustainability issue of ICT have gathered attention in recent years, and researchers are working on this problem. Sustainability incorporates numerous interconnected aspects as well as methods to achieve it in ICT, so it is quite complicated to have a general view on a problem without a proper framework. However, a general methodology for such a research is missing. In this work it is proposed to use Biomimicry approach as a framework for sustainability research and development, as it introduces systematics and also forces to account sustainable aspects. Additionally, an interesting problem of green network measurements for enhancing sustainability in ICT will be researched using mentioned approach. The goal is to investigate Biomimicry as a systemic approach for developing sustainable systems, as well as to apply it in green network measurements study. Comparative study is performed for examining Biomimicry approach, as well as a use case of green network measurements research is presented. As a result, green network measurement can potentially improve sustainability, but only to a limited extent as it cannot incorporate all the aspects; within Biomimicry approach, two methodologies exist. It is possible to conclude that Biomimicry is a good framework for developing sustainable systems, nevertheless, another methodology has to be introduced within it; new methodology has to incorporate advantages of two existing ones.
Resumo:
The European ambitious targets to increase the share of renewable generation pose a challenge to the generation adequacy. Many European member states are concerned that energy-only markets alone might not be able to deliver sufficient capacity required to meet the future electricity demand and back up shortfalls of energy from renewable energy sources (RES) during periods of low wind and sun. Many EU members consider to re-design their energy-only markets and establish different forms of capacity remunerative mechanisms (CRMs) to maintain the security of supply. There is a certain concern that market design changes at the level of EU member countries might conflict with the European goal of a single market. As soon as many European markets are highly interconnected, uncoordinated CRMs might create negative crossborder effects and hinder the achievement of the Internal Electricity Market in Europe. The pros and cons of capacity markets are well examined at the national level. However, the cross-border effects of capacity markets within the European market aiming at higher integration have received less attention. This doctoral dissertation examines the cross-border effects of unilateral implementation of CRMs applying both theoretical and case study analyses. The results show that capacity remunerative mechanisms (CRMs) may cause negative cross-border effects, especially if they are implemented unilaterally.
Resumo:
Tässä kandidaatintyössä selvitetään kirjallisuustutkimuksena, minkälaista tutkimusta maailmalla on tehty liittyen pienjännitteiseen tasasähkönjakeluun, sekä missä sovelluskohteissa sitä hyödynnetään. Työssä esitetään yleisimmät järjestelmärakenteet ja sovelluskohteet sekä organisaatiot, joiden on havaittu tutkivan tasasähkönjakelua kiinteistöissä, microgrideissä tai julkisessa sähkönjakelussa. Katsauksen perusteella havaittiin, että maailmalla on tehty erityisesti laskennallisia tutkimuksia ja simulointeja liittyen pienjännitteiseen tasasähkönjakeluun. Näkökulma on pääasiassa ollut kiinteistöissä ja microgrideissä, vähäisemmässä määrin myös julkisissa sähkönjakeluverkoissa. Pienjännitteistä tasasähkönjakelua hyödynnetään, tai ainakin voitaisiin hyödyntää näissä kohteissa. Pääasiassa konseptilla on pyritty hakemaan kustannussäästöjä ja toisaalta parantamaan hyötysuhdetta. Ympäri maailmaa on käynnissä pilottihankkeita sekä kiinteistöihin, että julkiseen sähkönjakeluun liittyen. Bipolaarinen ratkaisu näytti olevan yleisempi. Käytetyt ja tutkitut jännitetasot vaihtelivat riippuen sovelluskohteesta – kiinteistön sisällä oli käytössä tasot pienoisjännitteestä aina 350–400 VDC jännitetasoon asti, ja sama 350–400 VDC oli selvästi suosittu jännitealue myös jakeluverkossa, mutta myös korkeampia jännitteitä, kuten 700–750 VDC, oli käytössä.
Resumo:
IoT consists of essentially thousands of tiny sensor nodes interconnected to the internet, each one of which executes the programmed functions under memory and power limita- tions. The sensor nodes are distributed mainly for gathering data in various situations. IoT envisions the future technologies such as e-health, smart city, auto-mobiles automa- tion, construction sites automation, and smart home. Secure communication of data under memory and energy constraints is major challenge in IoT. Authentication is the first and important phase of secure communication. This study presents a protocol to authenticate resource constraint devices in physical proximity by solely using the shared wireless communication interfaces. This model of authentication only relies on the abundance of ambient radio signals to authenticate in less than a second. To evaluate the designed protocol, SkyMotes are emulated in a network environment simulated by Contiki/COOJA. Results presented during this study proves that this approach is immune against passive and active attacks. An adversary located as near as two meters can be identified in less than a second with minimal expense of energy. Since, only radio device is used as required hardware for the authentication, this technique is scalable and interoperable to heterogeneous nature of IoT.
Resumo:
Today, renewable energy technologies and modern power electronics have made it feasible to implement low voltage direct current (LVDC) microgrids (MGs) ca-pable to island operation. Such LVDC networks are particularly useful in remote areas. However, there are still pending issues in island operated LVDC MGs like electrical safety and controlled operation, which should be addressed before wide-scale implementation. This thesis is focused on the overall protection of an island operated LVDC network concept, including protection against electrical shocks, mains equipment protection and protection of photovoltaic (PV) power sources and battery energy storage systems (BESSs). The topic is approached through ex-amination of the safety hazards and the appropriate methods to protect against them, comprising considerations for earthing system selection and realisation of the protection system.
Resumo:
Increasingly growing share of distributed generation in the whole electrical power system’s generating system is currently a worldwide tendency, driven by several factors, encircling mainly difficulties in refinement of megalopolises’ distribution networks and its maintenance; widening environmental concerns adding to both energy efficiency approaches and installation of renewable sources based generation, inherently distributed; increased power quality and reliability needs; progress in IT field, making implementable harmonization of needs and interests of different-energy-type generators and consumers. At this stage, the volume, formed by system-interconnected distributed generation facilities, have reached the level of causing broad impact toward system operation under emergency and post-emergency conditions in several EU countries, thus previously implementable approach of their preliminary tripping in case of a fault, preventing generating equipment damage and disoperation of relay protection and automation, is not applicable any more. Adding to the preceding, withstand capability and transient electromechanical stability of generating technologies, interconnecting in proximity of load nodes, enhanced significantly since the moment Low Voltage Ride-Through regulations, followed by techniques, were introduced in Grid Codes. Both aspects leads to relay protection and auto-reclosing operation in presence of distributed generation generally connected after grid planning and construction phases. This paper proposes solutions to the emerging need to ensure correct operation of the equipment in question with least possible grid refinements, distinctively for every type of distributed generation technology achieved its technical maturity to date and network’s protection. New generating technologies are equivalented from the perspective of representation in calculation of initial steady-state short-circuit current used to dimension current-sensing relay protection, and widely adopted short-circuit calculation practices, as IEC 60909 and VDE 0102. The phenomenon of unintentional islanding, influencing auto-reclosing, is addressed, and protection schemes used to eliminate an sustained island are listed and characterized by reliability and implementation related factors, whereas also forming a crucial aspect of realization of the proposed protection operation relieving measures.
Resumo:
In this thesis, I explore how the folk-rock music of Ani DiFranco has influenced the activist commitments, sensibilities, and activities of reproductive rights activists. My interest in the relation of popular music to social movements is informed by the work of Simon Frith (1987, 1996a, 1996b), Rob Rosenthal (2001), and Ann Savage (2003). Frith argues that popular music is an important contributor to personal identity and the ways that listeners see the world. Savage (2003) writes that fans develop a unique relationship with feminist/political music, and Rosenthal (2001) argues that popular music can be an important factor in building social movements. I use these arguments to ask what the influence of Ani DiFranco's music has been for reproductive rights activists who are her fans. I conducted in-depth interviews with ten reproductive rights activists who are fans of Ani DiFranco's music. All ten are women in their twenties and thirties living in Ontario or New York. Each has been listening to DiFranco's music for between two and fifteen years, and has considered herself a reproductive rights activist for between eighteen months and twenty years. I examine these women's narratives of their relationships with Ani DiFranco's music and their activist experience through the interconnected lenses of identity, consciousness, and practice. Listening to Ani DiFranco's music affects the fluid ways these women understand their identities as women, as feminists, and in solidarity with others. I draw on Freire's (1970) understanding of conscientization to consider the role that Ani's music has played in heightening women's awareness about reproductive rights issues. The feeling of solidarity with other (both real and perceived) activist fans gives them more confidence that they can make a difference in overcoming social injustice. They believe that Ani's music encourages productive anger, which in turn fuels their passion to take action to make change. Women use Ani's music deliberately for energy and encouragement in their continued activism, and find that it continues to resonate with their evolving identities as women, feminists, and activists. My study builds on those of Rosenthal (2001) and Savage (2003) by focusing on one artist and activists in one social movement. The characteristics of Ani DiFranco, her fan base, and the reproductive rights movement allow new understanding of the ways that female fans who are members of a female-dominated feminist movement interact with the music of a popular independent female artist.