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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
Physico-Chemical Processes during Reactive Paper Sizing with Alkenyl Succinic Anhydride (ASA)
Get PDFSizing (hydrophobization) is one of the most important process steps within the added-value chain of about 1/3rd of the worldwide produced paper & board products. Even though sizing with so-called reactive sizing agents, such as alkenyl succinic anhydride (ASA) was implemented in the paper industry decades ago, there is no total clarity yet about the detailed chemical and physical mechanisms that lead to their performance. Previous research was carried out on the role of different factors influencing the sizing performance, such as bonding between ASA and cellulose, ASA hydrolysis, size revision as well as the most important interactions with stock components, process parameters and additives during the paper making process. However, it was not yet possible to develop a holistic model for the explanation of the sizing performance given in real life application. This thesis describes a novel physico-chemical approach to this problem by including results from previous research and combining these with a wide field of own basic research and a newly developed method that allows tracing back the actual localization of ASA within the sheet structure.
The carried out measurements and trial sets for the basic field of research served to evaluate the stock and process parameters that most dominantly influence the sizing performance of ASA. Interactions with additives other than retention aids were not taken into account. The results show that parameters, such as the content of secondary fibers, the degree of refining, the water hardness as well as the suspension conductivity, are of highest significance. The sample sets of the trials with the major impacting parameters were additionally analyzed by a newly developed localization method in order to better understand the main influencing factors.
This method is based on optical localization of ASA within the sheet structure by confocal white light microscopy. In order to fulfill the requirements at magnification rates of factor 100 optical zoom, it was necessary to improve the contrast between ASA and cellulose. Therefore, ASA was pretreated with an inert red diazo dye, which does not have any impact on neither the sizing nor the handling properties of ASA. Laboratory hand sheets that were sized with dyed ASA, were analyzed by means of their sizing performance in correlation to measurable ASA agglomerations in the sheet structure. The sizing performance was measured by ultrasonic penetration analysis. The agglomeration behavior of ASA was analyzed automatically by multiple random imaging of a sample area of approx. 8650 µm² with a minimum resolution for particles of 500 nm in size. The gained results were interpreted by full factorial design of experiments (DOE). The trials were carried out with ASA dosages between 0% and 0.8% on laboratory hand sheets, made of 80% bleached eucalyptus short fiber kraft pulp and 20% northern bleached softwood kraft pulp, beaten to SR° 30, produced with a RDA sheet former at a base weight of 100 g/m² oven dry.
The results show that there is a defined correlation between the ASA dosage, the sizing performance and the number and area of ASA agglomerates to be found in the sheet structure. It was also possible to show that the agglomeration behavior is highly influenced by external factors like furnish composition and process parameters. This enables a new approach to the explanation of sizing performance, by making it possible to not only examine the performance of the sizing agent, but to closely look at the predominant position where it is located in the sheet structure. These results lead to the explanation that the phenomenon of sizing is by far not a pure chemical process but rather a more physical one. Based on the gained findings it was possible so far to optimize the ASA sizing process in industrial-scale by means of ~ 50% less ASA consumption at a steady degree of sizing and improved physical sheet properties.:Acknowledgment I
Abstract III
Table of Content V
List of Illustrations XI
List of Tables XVI
List of Formulas XVII
List of Abbreviations XVIII
1 Introduction and Problem Description 1
1.1 Initial Situation 1
1.2 Objective 2
2 Theoretical Approach 3
2.1 The Modern Paper & Board Industry on the Example of Germany 3
2.1.1 Raw Materials for the Production of Paper & Board 5
2.2 The Sizing of Paper & Board 8
2.2.1 Introduction to Paper & Board Sizing 8
2.2.2 The Definition of Paper & Board Sizing 10
2.2.3 The Global Markets for Sized Paper & Board Products and Sizing Agents 11
2.2.4 Physical and Chemical Background to the Mechanisms of Surface-Wetting and Penetration 13
2.2.4.1 Surface Wetting 14
2.2.4.2 Liquid Penetration 15
2.2.5 Surface and Internal Sizing 17
2.2.6 Sizing Agents 18
2.2.6.1 Alkenyl Succinic Anhydride (ASA) 19
2.2.6.2 Rosin Sizes 19
2.2.6.3 Alkylketen Dimer (AKD) 23
2.2.6.4 Polymeric Sizing Agents (PSA) 26
2.2.7 Determination of the Sizing Degree (Performance Analysis) 28
2.2.7.1 Cobb Water Absorption 29
2.2.7.2 Contact Angle Measurement 30
2.2.7.3 Penetration Dynamics Analysis 31
2.2.7.4 Further Qualitative Analysis Methods 33
2.2.7.4.1 Ink Stroke 33
2.2.7.4.2 Immersion Test 33
2.2.7.4.3 Floating Test 34
2.2.7.4.4 Hercules Sizing Tester (HST) 34
2.2.8 Sizing Agent Detection (Qualitative Analysis) and Determination of the Sizing Agent Content (Quantitative Analysis) 35
2.2.8.1 Destructive Methods 35
2.2.8.2 Non Destructive Methods 36
2.3 Alkenyl Succinic Anhydride (ASA) 36
2.3.1.1 Chemical Composition and Production of ASA 37
2.3.1.2 Mechanistic Reaction Models 39
2.3.1.3 ASA Application 42
2.3.1.3.1 Emulsification 42
2.3.1.3.2 Dosing 44
2.3.1.4 Mechanistic Steps of ASA Sizing 46
2.3.2 Physico-Chemical Aspects during ASA Sizing 48
2.3.2.1 Reaction Plausibility 48
2.3.2.1.1 Educt-Product Balance / Kinetics 48
2.3.2.1.2 Energetics 51
2.3.2.1.3 Sterics 52
2.3.2.2 Phenomena based on Sizing Agent Mobility 53
2.3.2.2.1 Sizing Agent Orientation 54
2.3.2.2.2 Intra-Molecular Orientation 55
2.3.2.2.3 Sizing Agent Agglomeration 55
2.3.2.2.4 Fugitive Sizing / Sizing Loss / Size Reversion 56
2.3.2.2.5 Sizing Agent Migration 58
2.3.2.2.6 Sizing Reactivation / Sizing Agent Reorientation 59
2.3.3 Causes for Interactions during ASA Sizing 60
2.3.3.1 Process Parameters 61
2.3.3.1.1 Temperature 61
2.3.3.1.2 pH-Value 62
2.3.3.1.3 Water Hardness 63
2.3.3.2 Fiber Types 64
2.3.3.3 Filler Types 65
2.3.3.4 Cationic Additives 66
2.3.3.5 Anionic Additives 67
2.3.3.6 Surface-Active Additives 68
2.4 Limitations of State-of-the-Art ASA-Sizing Analysis 69
2.5 Optical ASA Localization 71
2.5.1 General Background 71
2.5.2 Confocal Microscopy 72
2.5.2.1 Principle 72
2.5.2.2 Features, Advantage and Applicability for Paper-Component Analysis 74
2.5.3 Dying / Staining 75
3 Discussion of Results 77
3.1 Localization of ASA within the Sheet Structure 77
3.1.1 Choice of Dyes 77
3.1.1.1 Dye Type 78
3.1.1.2 Evaluation of Dye/ASA Mixtures 80
3.1.1.2.1 Maximum Soluble Dye Concentration 80
3.1.1.2.2 Thin Layer Chromatography 81
3.1.1.2.3 FTIR-Spectroscopy 82
3.1.1.3 Evaluation of the D-ASA Emulsion 84
3.1.1.4 Paper Chromatography with D-ASA & F-ASA Emulsions 85
3.1.1.5 Evaluation of the D-ASA Emulsion’s Sizing Efficiency 86
3.1.2 The Localization Method 87
3.1.2.1 The Correlation between ASA Distribution and Agglomeration 88
3.1.2.2 Measurement Settings 89
3.1.2.3 Manual Analysis 90
3.1.2.4 Automated Analysis 92
3.1.2.4.1 Automated Localization / Microscopy Measurement 92
3.1.2.4.2 Automated Analysis / Image-Processing 93
3.1.2.5 Result Interpretation and Example Results 96
3.1.2.6 Reproducibility 97
3.1.2.7 Sample Mapping 98
3.1.3 Approaches to Localization-Method Validation 102
3.1.3.1 Raman Spectroscopy 102
3.1.3.2 Confocal Laser Scanning Fluorescent Microscopy 102
3.1.3.3 Decolorization 103
3.2 Factors Impacting the Sizing Behavior of ASA 104
3.2.1 ASA Type 105
3.2.2 Emulsion Parameters 107
3.2.2.1 Hydrolyzed ASA Content 107
3.2.2.2 ASA/Starch Ratio 109
3.2.2.3 Emulsion Age 110
3.2.3 Stock Parameters 111
3.2.3.1 Long Fiber/Short Fiber Ratio 111
3.2.3.2 Furnish Type 112
3.2.3.3 Degree of Refining 114
3.2.3.4 Filler Type/Content 116
3.2.4 Process Parameters 119
3.2.4.1 Temperature 119
3.2.4.2 pH-Value 120
3.2.4.3 Conductivity 122
3.2.4.4 Water Hardness 123
3.2.4.5 Shear Rate 125
3.2.4.6 Dwell Time 127
3.2.4.7 Dosing Position & Dosing Order 128
3.2.4.8 Drying 130
3.2.4.9 Aging 131
3.3 Factors Impacting the Localization Behavior of ASA 132
3.3.1 Degree of Refining 132
3.3.2 Sheet Forming Conductivity 135
3.3.3 Water Hardness 136
3.3.4 Retention Aid (PAM) 137
3.3.5 Contact Curing 138
3.3.6 Accelerated Aging 139
3.4 Main Optimization Approach 141
3.4.1 Optimization of ASA Sizing Performance Characteristics 142
3.4.2 Emulsion Modification 144
3.4.2.1 Lab Trials / RDA Sheet Forming 146
3.4.2.2 TPM Trials 147
3.4.2.3 Industrial-Scale Trials 149
3.4.2.4 Correlation between Sizing Performance Optimization and Agglomeration Behavior on the Example of PAAE 152
3.5 Holistic Approach to Sizing Performance Explanation 154
4 Experimental Approach 157
4.1 Characterization of Methods, Measurements and Chemicals used for the Optical Localization-Analysis of ASA 157
4.1.1 Characterization of used Chemicals 157
4.1.1.1 Preparation of Dyed-ASA Solutions 157
4.1.1.2 Thin Layer Chromatography 157
4.1.1.3 Fourier Transformed Infrared Spectroscopy 157
4.1.1.4 Emulsification of ASA 158
4.1.1.5 Paper Chromatography 159
4.1.1.6 Particle Size Measurement 159
4.1.2 Optical Analysis of ASA Agglomerates 160
4.1.2.1 Microscopy 160
4.1.2.2 Automated Analysis 163
4.1.2.2.1 Adobe Photoshop 163
4.1.2.2.2 Adobe Illustrator 164
4.1.2.3 Confocal Laser Scanning Fluorescent Microscopy 166
4.2 Characterization of Used Standard Methods and Measurements 166
4.2.1 Stock and Paper Properties 166
4.2.1.1 Stock pH, Conductivity and Temperature Measurement 166
4.2.1.2 Dry Content / Consistency Measurement 167
4.2.1.3 Drainability (Schopper-Riegler) Measurement 167
4.2.1.4 Base Weight Measurement 168
4.2.1.5 Ultrasonic Penetration Measurement 168
4.2.1.6 Contact Angle Measurement 169
4.2.1.1 Cobb Measurement 169
4.2.1.2 Air Permeability Measurements 170
4.2.1.3 Tensile Strength Measurements 170
4.2.2 Preparation of Sample Sheets 171
4.2.2.1 Stock Preparation 171
4.2.2.2 Laboratory Refining (Valley Beater) 171
4.2.2.3 RDA Sheet Forming 171
4.2.2.4 Additive Dosing 173
4.2.2.5 Contact Curing 174
4.2.2.6 Hot Air Curing 174
4.2.2.7 Sample Aging 174
4.2.2.8 Preparation of Hydrolyzed ASA 175
4.2.2.9 Trial Paper Machine 175
4.2.2.10 Industrial-Scale Board Machine 177
4.3 Characterization of used Materials 178
4.3.1 Fibers 178
4.3.1.1 Reference Stock System 178
4.3.1.2 OCC Fibers 179
4.3.1.3 DIP Fibers 179
4.3.2 Fillers 180
4.3.3 Chemical Additives 180
4.3.3.1 ASA 180
4.3.3.2 Starches 181
4.3.3.3 Retention Aids 181
4.3.3.4 Poly Aluminum Compounds 181
4.3.3.5 Wet Strength Resin 181
4.3.4 Characterization of used Additives 182
4.3.4.1 Solids Content 182
4.4 Description of Implemented Advanced Data Analysis- and Visualization Methods 183
4.4.1 Design of Experiments (DOE183
4.4.2 Contour Plots 184
4.4.3 Box-Whisker Graphs 185
5 Conclusion 186
6 Outlook for Further Work 191
7 Bibliography 192
Appendix 207
7.1 Localization Method Reproducibility 207
7.2 DOE - Coefficient Lists 208
7.2.1 Trial 3.3.4 – Impact of Retention Aid (PAM) on Agglomeration Behavior and Sizing Performance 208
7.2.2 Trial 3.3.5 – Impact of Contact Curing on Agglomeration Behavior and Sizing Performance 208
7.2.3 Trial 3.3.6 – Impact of Accelerated Aging on Agglomeration Behavior and Sizing Performance 20
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
Ressourcenschonung durch Leimungsmittelreduzierung bei der Herstellung von Papier und Karton (ReLeiPa) : Abschlussbericht
Get PDFAbschlussbericht zu dem IGF-Vorhaben "Ressourcenschonung durch Leimungsmittelreduzierung bei der Herstellung von Papier und Karton (ReLeiPa)" der Forschungsstelle (Hochschule für Angewandte Wissenschaften München)
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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