Predicting the Strength of Sawn Products by X-ray Scanning of Logs: A Preliminary Study

The aim of the study was to investigate the possibility of predicting the strength of centerboards from Norway spruce (Picea abies (L.) Karst.) saw logs, based on simulated X-ray LogScanner measurements. The study was based on eight logs. The logs were scanned using computed tomography (CT), four centerboards were sawn from each log, and the bending stiffness (MOE) and strength (MOR) of the boards were measured. The CT-images were used for simulations of the industrial X-ray LogScanner, resulting in simulated measurements of knot volume and the green density of heart-wood. Finally, multivariate models were calibrated using Partial Least Squares (PLS) regression. These models predict bending strength and stiffness based on the variables measured by the simulated X-ray LogScanner. Both bending strength and modulus of elasticity were defined as the mean value of the four boards from each log.The results were very promising, with strong models for prediction of both MOR (R2 = 0.73) and MOE (R2 = 0.94) mean values for all four boards from each log. The results indicate that the X-ray LogScanner can be used for the sorting of saw logs according to strength and stiffness. The next step should be to repeat the study on a larger sample of material

Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition

An X-ray LogScanner : a tool for control of the sawmill process

Wood is a biological material with great variability. Every piece of wood is a unique individual. The great challenge in the wood products manufacturing process has always been to select pieces of wood with properties that fulfil the product requirements. This will be even more important in the future as customers increasingly demand sawn products with special properties regarding dimension, moisture content, wrap and last, but not least, biological or aesthetic features. To be albe to fulfil these requirements, the right logs have to be selected for a certain product before the sawing process. This means that an accurate tool that can measure external and internal features is needed. The main objective of this work was to develop and evaluate algorithms for nondestructive measurement of external and internal properties in sawlogs with the aid of a bidirectional X-ray LogScanner. The LogScanner outlines and the LogScanner signals were simulated using CT (computer tomography) images from the Swedish Pine (Pinus sylvestris) Stem Bank and the European Spruce (Picea abies) Stem Bank. With the aid of data from the stem bank databases, the simulated scanner signals, the saw simulation program virtual SawMill (vSM), and statistical analysis programs, new control algorithms were developed and evaluated. The studies show that an X-ray LogScanner with two X-ray sources has a great potential to become a powerful tool for control of the sawmill process. The most important conclusions of work presented in this thesis were that: - X-ray based technology is a suitable technique for nondestructive measurement of internal features in green sawlogs. - CT scanning is a powerful research tool for measurement and visualisation of different log properties. - Parameterisation is an efficient method for reduction of the amount of data from a CT scanner. - It is very efficient to use data from a “Stem Bank data-base” based on CT scanning for simulation, analysis and development of the sawing process and different measurement technologies. - An X-ray LogScanner with two X-ray sources can measure log features such as diameter under bark, species, log type, knot structure, rotational position of knots, density, heartwood content, annual ring width and predict strength and grade of sawn boards.Godkänd; 1999; 20061117 (haneit

Verktygsförslitning. Mätmetodik inverkande faktorer

Syftet var att utveckla en metodik för mätning av förslitning och bestämning av skärdata vid hyvling och fräsning. I arbetet har också ingått en grov sållning bland de faktorer som inverkar på bearbetningsprocessen. Försöken har visat att verktygsförslitningen för en given material- /verktygskombination framför allt är beroende av skärlängden. Ur förslitnings-, buller- och dammsynpunkt bör spåntjockleken vara så stor som möjligt. En låg förslitning befrämjas även av en stor eggvinkel. Hur stor spåntjockleken och eggvinkeln kan tillåtas bli begränsas dock av vilka krav man ställer på de bearbetade ytornas kvalitet

Noggrannhet vid detektering av stockars inre kvalitet avrapportering steg 1

För att kunna öka värdeutbytet av råvaran vid sågverken krävs ny teknik. Detta är en systematisk kartläggning av vilken informationstäthet som krävs för att detektera och särskilja olika typer av avvikelser i de inre delarna av en stock. Två olika tekniker för genomlysning av stocken presenteras modifierad medicinsk tomografiteknik och s k scoutview-teknik

Predicting the strength of sawn wood products : a comparison between x-ray scanning of logs and machine strength grading of lumber

For a long time, process improvements in sawmills have focused on high productivity measured in volume per hour and volume recovery. As sawmills become increasingly efficient, the importance of focusing on value recovery becomes obvious. In order to maximize value recovery, sawmills need the ability to sort logs according to properties such as strength. The aim of this study was to compare the results of predicting the strength of center boards based on x-ray scanning of logs with the results obtained by machine strength grading using a bending machine. The study was based on 131 Norway spruce (Picea abies (L.) Karst.) sawlogs that were scanned with an x-ray LogScanner and then sawn into boards. The bending stiffness of the center boards was tested using a strength-grading machine, and the bending strength was tested according to EN 408. Models for prediction of bending strength based on machine strength grading and x-ray LogScanner measurements were calibrated using partial least squares regression. The study showed that the x-ray LogScanner (r2 = 0.44) and machine strength grading (r2 = 0.43) had similar accuracy in predicting bending strength. The combination of both methods resulted in significantly higher accuracy (r2 = 0.56). The root mean square error (RMSE) was 8.5 MPa for the bending machine, 8.4 MPa for the x-ray LogScanner, and 7.4 MPa for the combination of both methods. Consequently, the combination is an interesting alternative. Future studies should include a larger number of boards and focus on the effect of log carriers and on finding the reasons behind outliersValiderad; 2005; 20061017 (cira

Mätning av trädensitet och fuktinnehåll i trä kalibrering av datortomograf

I rapporten redovisas kalibrering av en datortomograf för mätning av densiteten hos trä och fukt i trä. Den innehåller en noggrann beskrivning av datortomografens arbetssätt och röntgenstrålningens absorption i materialet. Detta är nödvändigt för att läsaren/användaren skall kunna planera sina mätningar. Resultaten från kalibreringen redovisas ofta i form av exempel, vilket vi tror gör det lättare att förstå de problem som sammanhänger med datortomografens arbetssätt. Resultaten anger gränsen för hur små områden som kan datortomograferas med säker densitetsbestämning. Positioneringen av provet och mätområdet är mycket viktig

Metod för analys av limeffektiviteten i spånskivor

En metod har utvecklats, som gör det möjligt att identifiera karbamidlimmet på spån och i träbaserade skivor. Med metodens hjälp, och i kombination med bildanalys, kan man studera limmets fördelning på spånen och hur effektivt det utnyttjas i skivan. Metoden har utvecklats till en Trätek-service som vi erbjuder industrin. Kontakta Ingvar Johansson, tel 08-14 53 00, för mer information

Metod för analys av limeffektiviteten i spånskivor

En metod har utvecklats, som gör det möjligt att identifiera karbamidlimmet på spån och i träbaserade skivor. Med metodens hjälp, och i kombination med bildanalys, kan man studera limmets fördelning på spånen och hur effektivt det utnyttjas i skivan. Metoden har utvecklats till en Trätek-service som vi erbjuder industrin. Kontakta Ingvar Johansson, tel 08-14 53 00, för mer information