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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Laboratory method for the study of moisture-induced waviness in paper

Land, Cecilia January 2004 (has links)
<p>Paper that is subjected to moisture undergoes dimensional changes. It expands during moistening and shrinks during drying. When the paper is under tension between rollers, the effects are complex since shrinkage and expansion are restricted in the width direction. Waves can then appear on the paper web. This can be a problem in heatset web offset printing. The problem is known as waviness or fluting. The printed papers exhibit a wavy shape, which is visually disturbing due to light reflections which create glossy streaks. The aim of the work described in this thesis was to develop a method suitable for studying the moisture- and tension-induced waviness. Experiments were carried out on a laboratory scale to study how such waves develop during moistening and drying. The experimental setup was based on a modified tensile tester. A CCD camera and image analysis based on the STFI-OptiTopo technique was used to characterise the waviness. Moistening and drying were achieved by changing the surrounding air humidity. The method was used to study the effect of moisture uptake by the paper, and to evaluate the effect of tension on the waviness. It was found that increasing moisture resulted in a higher waviness amplitude, but that the web tension controlled the wavelength of the waviness. A high tension gave rise to a shorter wavelength. The measured wavelength was compared with a previously suggested model and the predicted wavelength was about twice as high as the measured wavelength.</p> / <p>When paper becomes damp it can develop waves which can be a problem with heatset web offset printing. Paper with waves may have glossy streaks after printing. Laboratory experiments studied the effect of moisture uptake by the paper. Readings were taken at a range of air humidities. The effect of tension on the waviness was also measured. The waviness was characterised using a charge coupled device (CCD) camera and the STFI-Packforsk OptiTopo technique to analyse the images. When the humidity was increased the amplitude of the waves increased. A high tension resulted in shorter wavelengths. Results from a previous model were used as a comparison.</p>
302

Split infinity (no blue, no green)

Miles, Lisa 01 May 2017 (has links)
No description available.
303

Drawing from the Book of Nature

Richard, Amy 01 May 2016 (has links)
My work is a response to the miraculous energy exhibited in nature, an invisible power that creates exquisite structures and designs in every living thing around us only to destroy them and begin again. Specifically, it is inspired by a lifelong fascination with the detritus left behind. Shimmering maple tree seeds, decaying oak leaves, or delicate marine relics awash on the beach are tangible (and daily) reminders that life is precious and fleeting, but also hopeful as that energy is always transformed into something new. The drawings, pulp prints and sculptures produced for my thesis are futher animated by the belief that nature is telling us something with its expressive vocabulary of lines, shapes, textures and colors. In every weather-worn remnant, there is a narrative—a life history and lessons to be learned. Captivated by the recurring forms and patterns found on land and in the sea, I find myself trying to decipher this language through close observation and interaction with the objects I collect, study and draw from, as well as the natural materials used to produce the work. Through the rituals of drawing and erasing, steaming, cooking and preparing fiber, concealing and revealing imagery, form and text, I find myself connecting with these narratives and participating in an age-old dialogue with nature.
304

Laboratory method for the study of moisture-induced waviness in paper

Land, Cecilia January 2004 (has links)
Paper that is subjected to moisture undergoes dimensional changes. It expands during moistening and shrinks during drying. When the paper is under tension between rollers, the effects are complex since shrinkage and expansion are restricted in the width direction. Waves can then appear on the paper web. This can be a problem in heatset web offset printing. The problem is known as waviness or fluting. The printed papers exhibit a wavy shape, which is visually disturbing due to light reflections which create glossy streaks. The aim of the work described in this thesis was to develop a method suitable for studying the moisture- and tension-induced waviness. Experiments were carried out on a laboratory scale to study how such waves develop during moistening and drying. The experimental setup was based on a modified tensile tester. A CCD camera and image analysis based on the STFI-OptiTopo technique was used to characterise the waviness. Moistening and drying were achieved by changing the surrounding air humidity. The method was used to study the effect of moisture uptake by the paper, and to evaluate the effect of tension on the waviness. It was found that increasing moisture resulted in a higher waviness amplitude, but that the web tension controlled the wavelength of the waviness. A high tension gave rise to a shorter wavelength. The measured wavelength was compared with a previously suggested model and the predicted wavelength was about twice as high as the measured wavelength. / When paper becomes damp it can develop waves which can be a problem with heatset web offset printing. Paper with waves may have glossy streaks after printing. Laboratory experiments studied the effect of moisture uptake by the paper. Readings were taken at a range of air humidities. The effect of tension on the waviness was also measured. The waviness was characterised using a charge coupled device (CCD) camera and the STFI-Packforsk OptiTopo technique to analyse the images. When the humidity was increased the amplitude of the waves increased. A high tension resulted in shorter wavelengths. Results from a previous model were used as a comparison.
305

An experimental study of air entrainment in a blade coating system with a pressurised pond applicator

Chen, Qingyuan 01 January 1998 (has links)
No description available.
306

The effect of paper structure on the deviation between tensile and compressive responses

Vorakunpinij, Adisak 05 1900 (has links)
No description available.
307

Investigation of wet paper cohesive properties

Guerrero Serrato, Alexander 09 July 2008 (has links)
Wet web paper cohesive properties behave in a similar way than tensile strength properties. The result was obtained using an unique apparatus developed by the IPST, which allows the cohesive strength determination for different wet web solids content. With the results a linear relation can be established between the cohesive strength index (obtained with the splitting apparatus) and the tensile strength index (obtained with the Instron). The splitting apparatus results can be used to calculate strain based on the work of Osterberg.
308

History of the formation of Western Pulp and Paper Workers

Graham, Harry E. January 1967 (has links)
Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
309

Fördröja åldrandet av elektrotekniskt papper genom kemikalietillsats : En studie av dicyandiamids påverkan / Delay the Ageing of Electro Technical Paper by Addition of Chemicals : A Study of the Effect of Dicyandiamide

Wilke, Caroline January 2011 (has links)
Nordic Paper Åmotfors tillverkar elektrotekniskt papper som används till att isolera lindningarna i transformatorer. Det är viktigt att bibehålla papprets egenskaper under en mycket lång tid då en transformators livlängd är lång. Syftet med detta examensarbete var att undersöka huruvida tillsats av en kemikalie bestående av dicyandiamid kan fördröja åldrandet av de papper som Nordic Paper tillverkar. Förhoppningen var att deras papper därefter skulle klara de krav-parametrar som finns för papper som åldrats i olja. Kemikalien som användes var Cartafix® WE liquid. Försök utfördes där olika kemikaliedoseringar tillsattes i mälden. Pappersark tillverkades och kvävehalten mättes därefter för att verifiera att kemikalien fastnat i de färdiga papprena. Pappers-arken åldrades sedan endera i olja eller i luft, och den kvarvarande polymerisationsgraden (DP) mättes. Sprängstyrke- och konduktivitetstester utfördes också. Papper som Nordic Paper tillverkat beströks med olika kemikaliedoseringar och samma tester utfördes även på dessa. Resultaten visade att retentionen av kemikalien var låg. Kvävehalten blev inte högre än 1 % och detta skedde vid 10-20 % kemikalietillsats. Efter åldring i olja minskade DP relativt mycket, vilket medförde att papprena inte uppnådde de uppsatta kraven (maximalt 50 % minskning). Tillsats av kemikalien förbättrade dock papprets åldringsegenskaper med nästan 45 % om icke-modifierat papper jämförs med det modifierade pappret som hade högst DP (10 % kemikalietillsats, vilket motsvarade 1 % kvävehalt). Papper som modifierats med kemikalietillsats i mälden gav lägre DP då åldringen skett i luft jämfört med icke-modifierat papper. DP minskade avsevärt efter åldring för papper som bestrukits med kemikalien. Kemikalietillsats försämrade både sprängstyrkan och konduktivteten. / Nordic Paper Åmotfors manufactures electro technical paper that is used to isolate the windings in transformers. It is important to maintain the properties of the paper during a long period of time because the life of a transformer is extensive. The purpose of this thesis was to investigate whether or not addition by a chemical consisting of dicyandiamide could delay the ageing of the papers that Nordic Paper manufactures. The aspiration was that their paper would then fulfil the requirements that are applicable to papers that have been aged in oil. The chemical that was utilised is called Cartafix® WE liquid. Experiments were conducted where different dosages of the chemical were added to the stock. Sheets of paper were manufactured and the nitrogen level was then measured in order to verify that the chemical had been fused in the finished paper. The paper sheets were then aged in either oil or air and the remaining degree of polymerisation was measured. Bursting strength and conductivity were also evaluated. Papers that Nordic Paper had manufactured were coated with different dosages of the chemical and then investigated in the same manner. The results showed that the retention of the chemical was relatively low. The nitrogen level did not exceed 1 %, which occurred at 10-20 % addition of the chemical. After ageing in oil, the degree of polymerisation was significantly reduced, which meant that the papers did not fulfil the requirement of a maximum of 50 % reduction. The addition of the chemical did however improve the ageing resistance with nearly 45 % if the unmodified paper is compared to the modified paper with the highest degree of polymerisation (10 % addition, equivalent to 1 % nitrogen). Papers that had been modified by addition of chemicals in the stock and had been aged in air exhibited lower degree of polymerisation than unmodified paper. The degree of polymerisation was significantly reduced for papers that had been coated and aged in air. Addition of chemicals resulted in both lower bursting strength and lower conductivity.
310

Paperspace : a novel approach to document management by combining paper and digital documents

Sallam, Samer 20 November 2006
Personal document management systems provide good support for storing and organizing digital documents. However, there are no computer tools that support organization of paper documents on our desks. We ran a study of people's organization of their office desk space with respect to their digital workspace. This study resulted in a set of requirements for a media bridging tool. Based on these requirements, we built a prototype media bridging tool called PaperSpace that uses computer vision to link paper and digital documents. The system also tracks piles of paper documents on the real desktop, and links those papers to digital documents stored in the computer. Digital documents can be sorted and grouped according to the physical layout of the corresponding papers on the desk. The system automatically creates digital piles of documents in a simulated desktop that reflect the paper piles on the real desktop. The user can access valuable information through the system, such as printing statistics, location of a printed document on the desk, and past projects and their documents. A two week user evaluation of the system showed interesting usage scenarios and future trends for improving user interaction.

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