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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.
1

Simulering av valkar i pappersrullar : och analys av de slappa stråk som uppkommer / Simulation of ridges in paper rolls : and analysis of the upcoming baggy webs

Brånn, Daniel January 2008 (has links)
<p>A baggy paper web has parts that are longer than neighboring parts. One of the assumed reasons for bagginess is thickness variations of the paper. In the roll the thicker streaks then add up to form a ridge. In the ridges the paper is strained and during storage the strain may become permanent. When the paper unreeled it is then baggy. Runability problems because of baggy webs is a common problem in the paper industry. Baggy webs can result in corrugations appearing when the paper is passing through nips during converting processes. Ridges have been simulated in this project by reeling thin plastic film into selected parts in the roll. Plastic was reeled in near the core, in the middle of the roll and in the periphery of the roll. To see if the paper web had got length differences the web was divided into stripes and with a special device the length of each stripe was measured. Even other paper properties were tested to determine if the ridges had other influences on the paper. Two of this properties was thickness and grammage, which were determined to see if the paper had got higher density in the baggy parts. The measurements show that the plastic results in bagginess but also that after a couple of days, the paper more or less has recovered to the initial thickness and sometimes also to the initial length. The most bagginess appeared near the core and it resulted in relatively large length differences, but even here the paper has likely recovered to some extent.</p> / <p>Då en pappersrulle har partier där pappret är längre kallas det ibland för slappa stråk. Det finns flera orsaker till slappa stråk och en av dessa orsaker är att pappret har en ojämn tjockleksprofil. I dessa fall uppstår de slappa stråken eftersom den ojämna tjockleksprofilen gör att pappersrullen på de positioner där pappret är tjockare får en större diameter än i övrigt. Då papper rullas över dessa åsar eller valkar som har en större diameter töjs pappret ut och då det rullas av rullen är det slappt. Körbarhetsproblem till följd av att pappret är slappt i vissa partier är ett stort problem inom pappersindustrin. Dessa körbarhetsproblem kan t.ex. vara att det uppstår veck i pappret då det passerar valsnyp.</p><p>I detta projekt har slappa stråk skapats genom att en viss mängd plast rullats in i pappersrullar dels i botten, dels i mitten samt ett parti närmast rullens periferi. Banspänningsmätningar har utförts för att se hur slappt pappret blivit där plast rullats in. För att se om pappret fått bestående längdskillnader i de slappa stråken har tvärsbanor tagits ur rullen och varje tvärsbana delats upp i remsor för att mäta längden på. Även andra pappersegenskaper har testats i dessa partier för att se om de slappa stråken påverkar papprets egenskaper. Bland annat har tjockleksprofilen mätts upp för att se om pappret komprimerats och fått en bestående densitetsökning i de slappa stråken. Mätningar visar dels att pappret blir slappt i partier där plast rullats in, men också att pappret efter några dagar i stort sätt helt återgått till sin ursprungstjocklek och vissa fall även i längdled. Pappret var som slappast i botten av rullarna och där uppmättes relativt stora längdskillnader även om pappret troligtvis återhämtat sig till en stor del även där.</p>
2

Simulering av valkar i pappersrullar : och analys av de slappa stråk som uppkommer / Simulation of ridges in paper rolls : and analysis of the upcoming baggy webs

Brånn, Daniel January 2008 (has links)
A baggy paper web has parts that are longer than neighboring parts. One of the assumed reasons for bagginess is thickness variations of the paper. In the roll the thicker streaks then add up to form a ridge. In the ridges the paper is strained and during storage the strain may become permanent. When the paper unreeled it is then baggy. Runability problems because of baggy webs is a common problem in the paper industry. Baggy webs can result in corrugations appearing when the paper is passing through nips during converting processes. Ridges have been simulated in this project by reeling thin plastic film into selected parts in the roll. Plastic was reeled in near the core, in the middle of the roll and in the periphery of the roll. To see if the paper web had got length differences the web was divided into stripes and with a special device the length of each stripe was measured. Even other paper properties were tested to determine if the ridges had other influences on the paper. Two of this properties was thickness and grammage, which were determined to see if the paper had got higher density in the baggy parts. The measurements show that the plastic results in bagginess but also that after a couple of days, the paper more or less has recovered to the initial thickness and sometimes also to the initial length. The most bagginess appeared near the core and it resulted in relatively large length differences, but even here the paper has likely recovered to some extent. / Då en pappersrulle har partier där pappret är längre kallas det ibland för slappa stråk. Det finns flera orsaker till slappa stråk och en av dessa orsaker är att pappret har en ojämn tjockleksprofil. I dessa fall uppstår de slappa stråken eftersom den ojämna tjockleksprofilen gör att pappersrullen på de positioner där pappret är tjockare får en större diameter än i övrigt. Då papper rullas över dessa åsar eller valkar som har en större diameter töjs pappret ut och då det rullas av rullen är det slappt. Körbarhetsproblem till följd av att pappret är slappt i vissa partier är ett stort problem inom pappersindustrin. Dessa körbarhetsproblem kan t.ex. vara att det uppstår veck i pappret då det passerar valsnyp. I detta projekt har slappa stråk skapats genom att en viss mängd plast rullats in i pappersrullar dels i botten, dels i mitten samt ett parti närmast rullens periferi. Banspänningsmätningar har utförts för att se hur slappt pappret blivit där plast rullats in. För att se om pappret fått bestående längdskillnader i de slappa stråken har tvärsbanor tagits ur rullen och varje tvärsbana delats upp i remsor för att mäta längden på. Även andra pappersegenskaper har testats i dessa partier för att se om de slappa stråken påverkar papprets egenskaper. Bland annat har tjockleksprofilen mätts upp för att se om pappret komprimerats och fått en bestående densitetsökning i de slappa stråken. Mätningar visar dels att pappret blir slappt i partier där plast rullats in, men också att pappret efter några dagar i stort sätt helt återgått till sin ursprungstjocklek och vissa fall även i längdled. Pappret var som slappast i botten av rullarna och där uppmättes relativt stora längdskillnader även om pappret troligtvis återhämtat sig till en stor del även där.
3

Detecção de Sclerotinia sclerotiorum em meio Neon-S modificado em sementes de soja e feijão / Detection of sclerotinia sclerotiorum in modified NEON-S medium in soybean and common beans seeds

Santos, Roberto Resende dos 24 February 2015 (has links)
The Neon-S method has been used for the detection of Sclerotinia sclerotiorum in soybean and common beans since the agricultural year 2010. However, this method yields false positive readings due to other fungi that change medium pH. Thus, this study evaluated the contribution of increasing incubation period on the optimization of Neon-S reliability in different cultivars of soybeans and common beans. Nine treatments were evaluated in randomized blocks design, as a 3x3 factorial, with three replications. The factors were three detection methods (paper roll, Neon- S, and Neon S2) and three cultivars: naturally infected Pérola beans; naturally infected soybean cultivar BRS Valiosa RR, and artificially inoculated soybean cultivar Nidera 7255 RR). Inoculation of soybean Nidera 7255 RR was done by incubating the seeds for 72 h on PDA where the fungus was previously grown for seven days at 25 ºC. The three methods were compared, evaluating 400 seeds per replication, after incubation for seven days in Neon-S, for 15 days in Neon-S2, and for 30 days in paper roll, determining the presence of the fungus, and that of sclerotia adhered to the seeds. Twenty seeds were used per plate for media Neon-S and Neon-S2 (20 plates per replication), and 50 seeds per roll for the paper roll. Seeds were incubated at 20 ºC in BDO chamber in darkness. The data were submitted to the analysis of variance and the averages compared by the Tukey test at 5% probability. The interaction between detection method and cultivar was significant at 1% probability, indicating that the best method depends on the cultivar under study. Among the cultivars evaluated, artificially infected soybean presented the greatest indices of pathogen infection. A comparison of seed lots analyzed at the Plant Disease Clinic LAMIP proved greater sensibility of Neon-S in a total of 637 lots evaluated from 2008 to 2012. In that period, the paper roll test resulted in 21.88% positive samples, while in Neon-S 31.25% of them were positive. Another distinguishing factor among the lots analyzed was the percentage of infected and, or, contaminated seeds, which varied from one (0.25%) to five (1.25%). Therefore, detection of S. sclerotiorum by the Neon-S2 method can be optimized by incubation for 15 days, considering that, in this case, the formation of sclerotia near the infected seeds confirm the presence of the pathogen, avoiding false positive readings. Neon-S2 method increased detection sensibility of S. sclerotiorum in seed lots analyzed in comparison with the paper roll method; however, in comparison with Neon S method, despite its greater average, no significant differences were observed. / O método de Neon-S tem sido utilizado para a detecção de Sclerotinia sclerotiorum em sementes de soja e feijão a partir da safra de 2010. Porém, esse método possibilita a leitura de falsos positivos devido ao aparecimento de fungos que também alteram o pH do meio. O objetivo deste trabalho foi verificar se o aumento do período de incubação pode contribuir para otimizar a confiabilidade do teste Neon-S em diferentes cultivares de soja e feijão. Foram avaliados nove tratamentos em delineamento de blocos casualizados no esquema fatorial 3x3, com três repetições, sendo três métodos de detecção: rolo de papel, Neon-S e Neon S2 e três cultivares: Feijão Pérola infectados naturalmente; soja cultivar BRS Valiosa RR infectadas naturalmente e soja cultivar Nidera 7255 RR inoculada artificialmente. Para a inoculação da soja Nidera 7255 RR, as sementes foram incubadas em meio de cultivo BDA por 72 h, após o cultivo do fungo por sete dias na temperatura de 25 ºC. Os três métodos foram comparados, avaliando 400 sementes por repetição, meio Neon-S com incubação de sete dias, Neon-S2 com incubação de quinze dias e o rolo de papel por trinta dias, anotando-se a presença do fungo e a presença de escleródios aderidos às sementes. No meio Neon-S e Neon-S2 foram utilizadas 20 sementes por placa (20 placas por repetição). No rolo de papel foram usadas 50 sementes por rolo. As sementes foram incubadas 20 ºC em BOD, no escuro. Realizou-se a análise de variância dos dados e teste de comparação de médias (Tukey 5%). A interação entre o método de detecção e a cultivar utilizada foi significativo a 1% de probabilidade, indicando que o melhor método depende da cultivar avaliada. Dentro das cultivares avaliadas, a soja infectada artificialmente foi a que apresentou os maiores índices de infecção pelo patógeno. Usando os resultados de lotes de sementes, comprovou-se a maior sensibilidade do Neon-S num montante de 637 lotes testados no período de 2008 a 2012. Durante esse período, o teste de rolo apresentou 21,88% de amostras positivas, enquanto que o Neon-S foi de 31,25%. Outro fator diferenciador em relação aos lotes analisados foi a porcentagem de sementes contaminadas e ou infectadas, que variou de uma (0,25%) a cinco (1,25%). Assim a detecção de S. sclerotiorum pelo método Neon-S2 pode ser otimizada com a incubação por 15 dias, considerando que, neste caso, a formação de escleródios próximos às sementes infectadas confirma a presença do patógeno e evita a leitura de falsos positivos. O método Neon-S2 aumentou a sensibilidade de detecção de S. sclerotiorum em lotes de sementes analisadas quando comparado ao método de rolo, porém, quando comparado com o método Neon S, sua média foi maior, mas a diferença não foi significativa. / Mestre em Agronomia
4

Machine-vision-based Detection of Paper Roll Core Eccentricity : Fast and Robust On-Line Measurement Using Circular Hough Transform

Sehlstedt, Erik January 2022 (has links)
The field of computer vision offers tools that allow machines to derive meaningful infor-mation from video and images and consequently make decisions based on visual inputs. In the paper industry, implementation of machine vision (MV) can be used to automate and speed up processes that require visual inspection, particularly certain segments of quality control – one such application being detection and measurement of paper roll core eccentricity. Core eccentricity is a roll build error in which the roll core is offset from the geometric roll center, potentially causing runnability issues. This particular project aims to improve the detection of paper roll core eccentricity at the Mondi Dynäs integrated pulp and paper mill through creation, calibration and evaluation of a machine-vision-based tool for on-line core eccentricity measurement. The tool utilizes the Hough Transform (HT), since HT is a simple yet fast and robust algorithm when it comes to identification of basic shapes such as lines and circles. The proposed solution was evaluated in two ways; firstly by determining at what level of accuracy the measurements could be provided, accounting for how well the solution deals with correction of systematic error caused by environmental factors, and secondly by analyzing how well characteristic roll features could be accurately identified in large sets of data, necessary to consistently perform measurements. The evaluation of the proposed solution showed a 99.9% detection rate for characteristic paper roll features, and a 98.1% detection rate of laser lines used for correction of position and orientation induced error. Assessment of the measurement accuracy following successful detection was on par with the current optical measurement method, and the proposed solution was able to classify distinctive features with a 96.8% accuracy. Lastly, several improvement actions to address faulty detection were identified, and factors to be considered for future installment were highlighted.

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