1,720,988 research outputs found
Parallel operation of portable solar-battery storage systems
No full textIn the United States, severe weather conditions such as thunderstorms, hurricanes, and blizzards are the leading cause of power outages. These power outages have caused life-threatening situations in the recent past for some cities. Historically, during some natural disasters and emergencies, the primary electrical grid gets damaged or fails to provide electricity to the affected areas efficiently. Especially in remote areas, such effects become even worse. Hence, there is a need for a sustainable electricity generation method to conduct regular operations and human survival in some cases.
Additionally, the stress caused on the environment due to traditional power generation methods, there is a need for a clean and green energy system. Solar energy is a highly researched energy system, and PV battery-based systems were used in past studies. However, the power output of one PV battery system is not enough to supply power to great critical electricity demand. Therefore, there is a need to increase the power output of the PV battery system. To fulfill these needs, the research question developed for this analysis was 'can multiple PV-battery systems operated in parallel and islanded mode provide sustainable and portable electricity to support critical electricity demands and supply energy to remote places?' To answer the research question, the objectives developed were (1) attaining the synchronization between the two PV-battery systems, (2) achieving voltage and frequency regulations, (3) establishing proportional real and reactive power sharing between PV-battery systems, and (4) achieving smooth operation in the islanded mode for multiple PV-battery systems. For this analysis, a portable PV-battery-based electricity generation system with six serial-connected 180W solar panels, a 2.1KWh battery pack, and a SYNDEM power converter is developed. Two PV-battery systems are operated in parallel using self-synchronized universal droop controller. Advanced power electronics control technologies are employed to achieve the autonomous operation of the PV battery systems. The incremental conductance-based Maximum power point tracking (MPPT) algorithm is used for harnessing maximum power from the PV panels. The result demonstrated that synchronization was achieved between the two systems. As a result, power output was maximized, and the system can support a load of 700W with only two systems in parallel. This project provides alternative solutions for community resiliency and energy independence. In remote monitoring applications, such as oil field monitoring systems, pipeline monitoring systems, communications, and critical electronic systems, also require continuous electricity supplies. This research provides a portable and sustainable electricity delivery system, a promising solution to address the above power demands.Embargo status: Restricted to TTU community only. To view, login with your eRaider (top right). Others may request the author grant access exception by clicking on the PDF link to the left
Nonparametric continuous-time identification of linear systems: theory, implementation and experimental results
Full text linkThis paper presents an algorithm for continuous-time identification of linear dynamical systems using kernel methods. When the system is asymptotically stable, also the identified model is guaranteed to share such a property. The approach embeds the selection of the model complexity through optimization of the marginal likelihood of the data thanks to its Bayesian interpretation. The output of the algorithm is the continuous-time transfer function of the estimated model. In this work, we show the algorithmic and computational details of the approach, and test it on real experimental data from an Electro Hydro-Static Actuator (EHSA)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Optimization-based reduction and Padé approximants for lithium-ion battery cell models with degradation
No full textThis works studies the model reduction of electrochemical lithium-ion battery cell models. Battery cell modeling is crucial to predicting battery behavior under different conditions and enables battery management system (BMS) control algorithms to ensure efficient and reliable operation. The finite difference method (FDM), commonly used for describing nonlinear battery dynamics, requires a high number of states to accurately capture the battery behavior. When computational resources are limited, model reduction is necessary to increase computational tractability and runtime. The literature presents a variety of reduced-order modeling techniques, though these techniques do not commonly incorporate degradation dynamics. To address this gap, this study explores model reduction with the inclusion of degradation effects. Two methods are used to accomplish this. The first uses optimization-based techniques to identify reduced-order models, and the second extends the Padé approximation technique to incorporate degradation terms found in the boundary conditions of the single-particle model (SPM). The models produced are compared for different operating conditions of a lithium-ion battery cell. Simulated case studies indicate that both reduction techniques are able to capture the cell dynamics with degradation only using a few states
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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