104,609 research outputs found
Degradation of Biomass Pellets during Transport, Handling and Storage: An experimental and numerical study
No full textPresently, biomass pellets play a significant role in energy transition scenarios worldwide. Due to the lack of local supplies, many countries import their pellets from countries with enormous resources. For instance, in Europe, a big share of pellets is imported from the USA, Canada, and Asian countries. Pellets are normally transferred in bulk using ocean vessels with a capacity of up to 40,000 metric tons. Due to mechanical forces and environmental changes throughout the transport and storage steps, pellets are prone to degradation. This may degrade pellets physically or chemically. As a result, fines and dust are generated. Moreover, as pellets absorb and adsorb moisture from the environment, the moisture content and the heating value of pellets may change, and this may also weaken the physical structure because of swelling. The presence of fines and dust may lead to self-ignition and dust explosion, material loss, equipment fouling, and environmental and health issues. The goal of this dissertation is to investigate to what extent biomass pellets degrade during transport and storage. To achieve this, first, we conducted an extensive literature review to reveal the factors that affect the extent of degradation of pellets. Moreover, we studied the commonly used methods to assess the quality parameters and the degradation behavior of pellets in detail. Then, we carried out a series of experiments on physical and chemical degradations of pellets from laboratory to large-scale and analyzed them in the operational and environmental context. By conducting these experiments, we unveiled the relationship between the laboratory test results and the pilot or large-scale transport impact on the proportion of generated fines. Furthermore, a model in the discrete element method (DEM) was developed and used to simulate the breakage pattern of individual pellets under the compression test. The model shows high fidelity in simulating the breakage behavior of pellets under compressive forces in two directions.Large Scale Energy Storag
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Contribution of Information and Communication Technology (ICT) in Country’S H-Index
No full textThe aim of this study is to examine the effect of Information and Communication Technology (ICT) development on country’s scientific ranking as measured by H-index. Moreover, this study applies ICT development sub-indices including ICT Use, ICT Access and ICT skill to find the distinct effect of these sub-indices on country’s H-index. To this purpose, required data for the panel of 14 Middle East countries over the period 1995 to 2009 is collected. Findings of the current study show that ICT development increases the H-index of the sample countries. The results also indicate that ICT Use and ICT Skill sub-indices positively contribute to higher H-index but the effect of ICT access on country’s H-index is not clear
Fully Turbulent Mean Velocity Profile for Purely Viscous non-Newtonian Fluids
No full textThe characteristic near wall behavior of turbulent flow of purely-viscous non-Newtonian fluids is discussed for both power-law (P.-L.) and Herschel-Bulkley (H.-B.) rheological models. A proper scaling is presented for H.-B. fluids to establish an analogy with power-law fluids with same flow index. To provide reference data for turbulent flow of non-Newtonian fluids, DNS simulations of power-law fluids are conducted in a rectangular channel for a large range of power-law indices ( = 0.5, 0.69, 0.75, 0.9, 1, 1.2). The DNS data show that the mean velocity profile in the viscous and logarithmic layers follow expressions of the form and respectively, where shows a logarithmic dependency on the flow index.Comparison with some experimental data shows the above formulation to be valid for Reynolds numbers (based on shear velocity) as high as 1000
H-index and research evaluation: A suggested set of components for developing a comprehensive author-level index
No full textThe H-index has been investigated in various studies; this index has many strengths that have made it popular. However, it also has weaknesses, due to which other indicators have been developed. This study aims to identify the strengths and weaknesses of the H-index and provide the minimum set of necessary components for developing a comprehensive author-level index. In this systematic literature review, Scopus, PubMed, Web of Science, Emerald, and ProQuest databases were searched to identify relevant studies. From the number of 14,253 retrieved studies, after two stages of screening, 81 studies were selected according to the eligibility criteria for data extraction. The findings of the study led to the identification of 15 strengths in the three categories of Quality Features, Simplicity, and Suitability, and 13 weaknesses in the six categories of Publications, Citations, Academic Age, Author Credit Allocation, Variety of Fields, and mathematical calculation for H-index. Finally, 28 components were identified as the minimum set of necessary components to develop a comprehensive author-level index to help evaluate researchers more realistically and fairly. The minimum components that need to be considered in developing a comprehensive author-level index can be proposed as follows: Quality Features, Simplicity, Suitability, Publications, Citations, Academic Age, Author Credit Allocation, Variety of Fields, and mathematical calculation
The Effect of Pellet Length on Mechanical Durability and Breakage Behaviour of Torrefied Biomass
No full textThe transportation, handling, and storage of biomass pellets are challenging due to pellet breakage and fines generation. The amount of fines generated during transportation and handling of biomass pellets is mostly measured in the laboratory using mechanical durability testers such as tumbling can method according to ISO 17831-1. This standard sets requirements on the amount of pellets, but not on the pellet length distribution (PLD) to be used for the mechanical durability measurements. This study aims to investigate the effect of PLD on the mechanical durability of biomass pellets. Two different types of torrefied biomass of Poplar and Mixed wood were used in this study. Samples were classified into three different groups of shorter than 15 mm, between 15 and 30 mm, and longer than 30 mm before durability test. In addition, a random PLD was considered as a reference case. The results show that the mechanical durability strongly depends on the PLD and increases from 83.6% to 96.4% for torrefied Poplar and from 92.7% to 98.5% for torrefied Mixed wood by increasing the PLD from shorter than 15 mm to longer than 30 mm. Therefore, it is highly recommended to consider the PLD of the pellet samples before durability tests.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and LogisticsLarge Scale Energy Storag
Letter from Bob H. Suzuki, President, CSU Pomona, June 13, 1993
No full textA letter from President Bob H. Suzuki thanking guests of a garden reception and asking for their support to fund Michi Nishiura and Walter Weglyn Endowed Chair in Multicultural Studies.These materials are from box 73 and 74 of the Frank Chin Papers. The Frank Chin Papers contain personal and professional correspondence between Frank Chin and Michi Weglyn relating to particular projects on which either author was working as well as files related to the Day of Remembrance Tribute to Michi Weglyn
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