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This paper is concerned with a technique for detecting and monitoring abnormal paper formation variations in machine direction online in various frequency regions. A paper web is illuminated by two red diode lasers and the reflected light recorded as two time series of high resolution measurements constitute the input signal to the papermaking process monitoring system. The time series are divided into blocks and each block is analyzed separately. The task is treated as kernel based novelty detection applied to a multi-resolution time series representation obtained from the band-pass filtering of the Fourier power spectrum of the time series block. The frequency content of each frequency region is characterized by a feature vector, which is transformed using the kernel canonical correlation analysis and then categorized into the inlier or outlier class by the novelty detector. The ratio of outlying data points, significantly exceeding the predetermined value, indicates abnormalities in the paper formation. The experimental investigations performed have shown good repetitiveness and stability of the paper formation abnormalities detection results. The tools developed are used for online paper formation monitoring in a paper mill.

With the help from accelerator mass spectrometry (AMS), hair from workers within the nuclear power industry, pharmaceutical and biotechnology industry has been investigated to see if contamination from 14C. 14C-using companies and nuclear power plants were contacted, volunteers were recruited, who sent in hair samples together with a questionnaire. The samples were washed and prepared for 14C analysis with a single stage AMS (SSAMS) machine. Different ways were tried to remove sulphur impurities form the hair samples. Hair collected at hairdresser saloons was analysed to act as a background indicator. Contaminations were found in two samples that were in the order of 12 and 78 times higher than normal background. Also smaller contaminations were found in 12 samples that indicate a general contamination in the work environment. Further studies are needed to investigate if the contamination is entirely internal, and not to some extent external 14C absorbed by the hair. If the 14C contamination is mainly internal, this work suggests that the workers at least should be made aware of the amount of 14C they receive internally. The work presented in this master’s thesis shows that our graphitization method is good for hair and AMS can be used as a tool to monitor small amounts of 14C in hair., Inom kärnkraftsverken, läkemedelsindustrin, biotekniklaboratorier mfl är det vanligt att det radioaktiva ämnet 14C förekommer i olika former. Inom kärnkraftsverken som en biprodukt vid elproduktion och inom läkemedelsindustrin används det som markör för att studera hur sunbstansen distribueras i kroppen. Genom inandning vid t ex oförsiktighet kan de människor som arbetar med dessa olika substanser komma att exponeras för små mängder 14C, vilket bl a kan visa sig som en 14C-förekomst i håret. För att undersöka förekomsten av 14C i hår kan acceleratormass-spektrometri (AMS) användas som är ett verktyg, vilken även används bl a för åldersbestämning av t.ex. arkeologiska och geologiska föremål. AMS har fördelen att kunna mäta ytterst små prover. Idag används AMS inom arkeologi, klimatforskning, biomedicin och läkemedelsforskning, rättsmedicin m.m. Ett AMS-system har många fördelar jämfört med klassisk masspektrometri, t.ex. att jonkällan, som producerar negativa joner, vilket minskar bakgrunden från andra nuklider eller molekyler med massan 14. Resultatet från AMS-maskinen erhålls i pMC (percent modern carbon). Detta motsvarar 2.26 Bq/kg kol. Ett frågeformulär skickades ut tillsammans med ett informationsbrev till berörda institutioner/företag och dylikt för att höra om intresse fanns att deltaga i denna studie. För att ha något att jämföra detta hår med måste även hår från en grupp personer insamlas som inte arbetar i 14C-miljöer, eftersom 14C också finns naturligt. Därför insamlades hår från frisörsalonger som skulle agera som bakgrund, för att dras bort från de skarpa proverna. Hårproven tvättas i etanol för att ta bort eventuell extern kontaminering av 14C, dvs. 14C som ligger utanpå håret till följd av att substanserna på något sätt hamnat där. Därefter förbereddes proverna genom att förbrännas till koldioxid, köras genom olika rengöringssystem som vi utvecklat för hår, och till sist dunstas ned till fast kol genom olika kemiska processer. När respektive prov är kl

A measurement platform for online studies of print runnability in a full-scale four-high web offset printing press is described. Results from two trial runs showed no effect of reel tightness on print runnability. Differences were, however, found for so called edge reels.

NQC

When water is removed from the paper during paper making, a dimensional change occurs in which the paper shrinks in the direction perpendicular to the direction of processing. The dimensional changes vary across the web and influence, e.g., the surface and compression properties of the paper; they also complicate the control of the paper machine. In this article, a robust method for estimating the relative shrinkage profile is presented. The method is based on a one-dimensional recording of the imprints from the forming fabric, using a fluorescence technique. The recording is transformed into a time-frequency spectrum, on which three different frequency estimators have been evaluated. In simulations on synthetic data and measurements on paper profiles the estimator that maximizes the correlation energy showed the most robust and accurate performance of the methods evaluated, even at a low signal-to-noise ratio.

NR 20140805

Fluorescence from paper following excitation by either ultraviolet or visible light gives information on the chemical composition of the paper. This can be used for on-line monitoring of the paper during production. Such measurements can be performed non-intrusively at sampling rates high enough to give a sub-millimetre resolution at paper webs moving at velocities higher than 20 metres per second. Two types of fluorescence meters, operating at different wavelengths, have been constructed. Together with an optical speedometer they have been tested at newsprint producing paper mills. A fluorescence based method for scanning cross-directional newsprint profiles in the laboratory has been developed. From these measurements the relative shrinkage of the paper during drying can be calculated using time-frequency analysis.