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Abstracts of PhD theses: PRODEM - Doctoral Program in Mechanical Engineering
No full textThis booklet contains extended abstracts of PhD theses of the Doctoral Program in Mechanical Engineering (PRODEM), DEMec, Faculty of Engineering, University of Porto, Portugal. These theses were defended between 1 September 2023 and 31 July 2024, corresponding approximately to the academic year 2023-2024.The booklet contains nineteen extended abstracts covering diverse topics within the broad field of Mechanical Engineering. These include, but are not limited to, innovative methodologies in gear design, varied aspects of composite materials and their applications, simulation-driven product analysis and development, additive and other manufacturing techniques, studies of adhesive joints, fatigue and structural health monitoring, passive vibration control, application of solar energy, and the analysis of viscoelastic fluid flows. The abstracts are organised by the defence date and, when more than one defence occurred on the same day, by the name of the student.PRODEM is very grateful to the former students for preparing these abstracts and extends its acknowledgment to both the students and their supervisors for the development of the corresponding PhD theses. The abstracts, and the sample publications mentioned in a few of them, illustrate the vibrant intervention of PRODEM students and their supervisors in the scientific community.The success of PRODEM is built upon an active research environment, the knowledge and conditions accumulated by the host and collaborating institutions, and the dedication and expertise of students, lecturers and supervisors. Various funding sources, alongside FEUP’s contribution as host institution, supported the PhD theses. Most extended abstracts include acknowledgments to the respective funding sources, to which PRODEM also expresses its gratitude
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Kömür yakıtlı bir termik santralde değirmen kanalsisteminin sayısal incelemesi ve jeotermal bir santralde alternatif evaporatif soğutma yöntemlerinin değerlendirilmesi ile verimlilik artışlarının analizi
No full textNearly over 62,000 power plants in the world are operating to produce people's electricity needs. Coal-fired power plants are being among the most common plants in electricity production. In contrast, geothermal plants can be considered to be the most reliable ones from the renewable energy sources aspect. As these power plants are planned to be operated based on their design data, their real-time electricity production can show variation from the designed values. In the present study, both a coal-fired thermal power plant (TPP) in Manisa, Turkey, and a geothermal plant in Aydın, Turkey, were investigated to identify efficiency losses and provide recommendations on efficiency improvements for these plants. Firstly, coal/air flow in the mill duct system in the Soma B TPP was numerically modeled to characterize the flow behavior of the coal particles and gas mixture. The two new design alternatives of the mill duct system, named ND-01 and ND02, were proposed to provide a better mixing at the duct system. It was realized that more homogenous particle disturbance was obtained in the mill duct system, especially for the particle sizes larger than 230 µm when ND-01 design is placed into the duct system. Secondly, the thermodynamical performance of a 21 MW geothermal plant with an aircooled two-level binary type organic Rankine cycle was numerically investigated based on its design and operating data. The study results show that when the ambient temperature rises from 5°C to 35°C, the power generation of the plant has a decrease of 6.8 MW at nominal load, energy efficiency has decreased from 13.5 percent to 9.98 percent and exergy efficiency is reduced from 54.65 percent to 38.67 percent. Furthermore, thermoeconomic analysis was carried out to determine the most profitable and economical evaporative cooling system for the plant by considering the payback period, internal rate of return (IRR), and net present value (NPV) methods. The payback periods of direct spray, wetted media, and ecomesh methods are calculated to be 8.4, 11.2, and 14.0 years, respectively. Besides, the direct spray system appears to be the most advantageous investment alternative among the others based on IRR and NPV results.Turkish: Dünyadaki yaklaşık 62.000'den fazla enerji santrali, insanların elektrik ihtiyaçlarını karşılamak için işletilmektedir. Kömür santralleri elektrik üretiminde en yaygın santraller arasındadır. Buna karşılık, jeotermal santraller yenilenebilir enerji kaynakları açısından en güvenilir santraller olarak kabul edilebilir. Bu santraller tasarım değerlerine göre çalıştırılması planlandığından, gerçek zamanlı elektrik üretimi tasarlanan üretim değerlerinden farklılıklar gösterebilir. Bu çalışmada, hem Manisa, Türkiye'deki bir kömür termik santrali (TS) hem de Aydın, Türkiye'deki bir jeotermal santrali verim kayıplarının belirlenmesi ve verimlilik iyileştirmeleri konusunda önerilerde bulunmak amacıyla araştırılmıştır. İlk olarak, Soma B TS'deki değirmen kanalı sistemindeki kömür/hava akışı, kömür parçacıklarının ve gaz karışımının akış davranışını karakterize etmek için sayısal olarak modellenmiştir. Değirmen kanalı sisteminde daha iyi bir karışım sağlaması için ND01 ve ND-02 adlı iki yeni tasarım önerildi. Kanal sisteminde özellikle ND-01 tasarımı uygulandığında, 230 µm'den daha büyük partikül boyutları için daha homojen partikül dağılımının elde edildiği anlaşıldı. İkincisi, hava soğutmalı iki kademeli binary tip organik Rankine çevrimine sahip 21 MW'lık bir jeotermal santralin termodinamik performansı, tasarım ve işletim verilerine göre sayısal olarak araştırıldı. Sonuçlar, ortam sıcaklığı 5 °C'den 35 °C'ye yükseldiğinde, santralin elektrik üretiminin nominal yükte 6.8 MW azaldığını, enerji verimliliğinin yüzde 13.5'ten yüzde 9.98'e düştüğünü ve ekserji verimliliğinin yüzde 54.65'ten yüzde 38.67'ye azaldığını göstermektedir. Ayrıca, geri ödeme süresi, iç getiri oranı ve net bugünkü değer yöntemleri göz önünde bulundurularak santral için en karlı ve ekonomik olan soğutma yöntemini belirlemek amacıyla bu üç ayrı evaporatif soğutma sistemi yatırımı için termoekonomik analiz yapılmıştır. Doğrudan sprey, ıslak ortam ve ekomesh yöntemlerinin geri ödeme süreleri sırasıyla 8.4, 11.2 ve 14.0 yıl olarak hesaplanmıştır. Ayrıca, IRR ve NPV sonuçlarına dayanarak doğrudan sprey sistemi, alternatifler arasında en avantajlı yatırım seçeneği olduğu görülmektedir.The Yeditepe University Open Access System is a compilation of national and international indexed publications for the institutional archive of scientific publications prepared by Yeditepe University students (graduate, doctoral, and/or equivalent). Copyright and rights of use may belong to the authors and/or Yeditepe University.YÖK id number : 627322ACKNOWLEDGEMENTS .............................................................................................. iii ABSTRACT ..................................................................................................................... iv ÖZET ................................................................................................................................ v LIST OF FIGURES ........................................................................................................ viii LIST OF TABLES .......................................................................................................... xv LIST OF SYMBOLS/ABBREVIATIONS.................................................................... xviii 1. INTRODUCTION...................................................................................................... 1 1.1. POWER GENERATION IN THE WORLD ........................................................ 1 1.2. POWER GENERATION IN TURKEY ............................................................... 2 1.3. PULVERIZED COAL FIRED THERMAL POWER PLANTS ........................... 3 1.4. GEOTHERMAL POWER PLANTS ................................................................... 4 1.5. LITERATURE SURVEY.................................................................................... 6 1.5.1. The Mill Duct Systems in Coal-Fired TPPs .................................................. 6 1.5.2. Binary Cycle ORC Geothermal PPs ............................................................. 8 1.6. AIMS, OBJECTIVES, AND MOTIVATIONS OF THE THESIS ..................... 13 1.6.1. Aims and Objectives of the Thesis ............................................................. 13 1.6.2. Motivations of the Thesis ........................................................................... 17 2. MATERIAL AND METHOD .................................................................................. 20 2.1. THE MILL DUCT SYSTEM OF THE SOMA B THERMAL POWER PLANT 20 2.1.1. System Description .................................................................................... 20 2.1.2. Plant Performance Tests ............................................................................. 23 2.1.3. Numerical Analysis .................................................................................... 28 2.2. THE STUDIED GEOTHERMAL POWER PLANT ......................................... 36 2.2.1. Numerical Simulation Model ..................................................................... 37 2.2.2. Governing Equations for Thermodynamic Analysis.................................... 43 2.2.3. Analyzing of ACC system of the GPP ........................................................ 48 2.2.4. Thermodynamic Analysis of Evaporative Cooling Systems ........................ 54 2.2.5. Economic Analysis of Evaporative Cooling Systems .................................. 75 3. RESULTS AND DISCUSSION ............................................................................... 77 vii 3.1. THE MILL DUCT SYSTEM OF THE SOMA B THERMAL POWER PLANT 77 3.1.1. The Soma Thermal Power Plant Test Results and Evaluation of Boiler Efficiency ................................................................................................................. 77 3.1.2. Numerical Analysis Results ........................................................................ 82 3.1.3. New Coal Duct Design for Better Performance .......................................... 87 3.2. THE STUDIED GEOTHERMAL POWER PLANT ......................................... 89 3.2.1. Exergy Destruction Analysis ...................................................................... 89 3.2.2. Improvement Potential Analysis ................................................................. 92 3.2.3. Energy and Exergy Flow Diagram Analysis ............................................... 93 3.2.4. Influence of Ambient Temperature on GPP Performance ........................... 95 3.2.5. Thermodynamic Analysis of Evaporative Cooling Systems ........................ 99 3.2.6. Economic Analysis of Evaporative Cooling Systems ................................ 118 4. CONCLUSION ...................................................................................................... 146 REFERENCES.............................................................................................................. 14
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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