| 1. |
- Antti, Henrik, et al.
(författare)
-
Detection of kappa number distributions in kraft pulps using nir spectroscopy and multivariate calibration
- 2000
-
Ingår i: TAPPI Journal. ; 83:3, s. 102-8
-
Tidskriftsartikel (refereegranskat)abstract
- Chemical pulp is characterized by its average lignin content, commonly expressed as the pulp-kappa number. However, this average kappa number provides no information about the distribution of kappa number within the pulp . This study proposes a new method of pulp characterization using near-infrared reflectance (NIR) spectroscopy to measure distributions of kappa numbers within pulp samples. Pure pulps with different kappa numbers were mixed to create blended samples with a known nonuniformity of kappa number distribution. NIR spectroscopy-combined with multi-variate calibration methods was used to detect distributions of kappa numbers in the pulps. Models calculated from these data gave good predictions of the average kappa number as well as the standard deviation around the average. The results imply that NIR spectroscopy can provide information about the average kappa number as well as the distribution of kappa number within the pulp.
|
|
| 2. |
- Aspeborg, Henrik, 1970-, et al.
(författare)
-
Vegetabile material, plants and a method of producing a plant having altered lignin properties
- 2008
-
Patent (populärvet., debatt m.m.)abstract
- The present invention is related to a set of genes, which when modified in plants gives altered lignin properties. The invention provides DNA construct such as a vector useful in the method of the invention. Further, the invention relates to a plant cell or plant progeny of the plants and wood produced by the plants according to the invention Lower lignin levels will result in improved saccharification for bio-refining and ethanol production and improved pulp and paper. Increased lignin levels will utilise lignin properties for energy production. The genes and DNA constructs may be used for the identification of plants having altered lignin characteristics as compared to the wild-type. According to the invention genes and DNA constructs may also be used as candidate genes in marker assisted breeding.
|
|
| 3. |
- Jonsson, Pär, et al.
(författare)
-
Strategies for implementation and validation of on-line models for multivariate monitoring and control of wood chip properties
- 2004
-
Ingår i: Journal of Chemometrics. - : Wiley. - 0886-9383 .- 1099-128X. ; 18:3-4, s. 203-7
-
Tidskriftsartikel (refereegranskat)abstract
- Here we present an approach for on-line control and monitoring of pulpwood chip properties based on near infrared (NIR) spectroscopy and multivariate data analysis. In addition, this paper suggests how to deal with large multivariate data sets in order to extract information which can be used as a basis for changes in raw material or process conditions in the drive towards more optimal intermediate or end product properties within the pulp and paper industry. The pulpwood chips used as raw material in a pulp and paper making process were characterized at- and on-line using NIR spectroscopic measurements. Collected NIR spectra were used in multivariate calibration models for prediction of the moisture content as well as the between- and within-species variation in the studied raw material. Statistical experimental design was used to form a calibration data set including most of the variation occurring in a real on-line situation. NIR spectra for all designed samples were measured at-line and the estimated calibration models were used for carrying out predictions on-line. Predictions of the moisture content (% dry weight) as well as the percentage contents of pine and sawmill chips in the raw material were carried out using partial least squares projections to latent structures (PLS) methodology. NIR spectra were collected subsequently on-line once every minute, and, to reduce the problem with noise in the time series predictions, the measured signals were filtered using a moving average of 100 predicted values. This provided smoother predictions more suitable for process monitoring and control. To validate the quality of the predictions, wood chips from the studied process were sampled and analysed in the laboratory before being subjected to predictions in the on-line model. Comparison of the filtered on-line predictions with the results obtained from the laboratory measurements indicated that moisture and pine chip contents could be well predicted by the on-line model, while predictions of sawmill chip content showed less promising results.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Oja, Johan, et al.
(författare)
-
Automatic grading of Scots pine (Pinus sylvestris L.) sawlogs using an industrial X-ray log scanner
- 2003
-
Ingår i: Computers and Electronics in Agriculture. - 0168-1699 .- 1872-7107. ; 41:1-3, s. 63-75
-
Tidskriftsartikel (refereegranskat)abstract
- The successful running of a sawmill is dependent on its ability to achieve the highest possible value recovery from the sawlogs, i.e. to optimize the use of the raw material. Such optimization requires information about the properties of every log. One method of measuring these properties is to use an X-ray log scanner. The objective was to determine the accuracy when grading Scots pine (Pinus sylvestris L.) sawlogs using an industrial scanner known as the X-ray LogScanner. The study was based on 150 Scots pine sawlogs from a sawmill in northern Sweden. All logs were scanned in the LogScanner at a speed of 125 m/min. The X-ray images were analyzed on-line with measures of different properties as a result (e.g. density and density variations). The logs were then sawn with a normal sawing pattern (50 × 125 mm) and the logs were graded depending on the result from the manual grading of the center boards. Finally, partial least squares (PLS) regression was used to calibrate statistical models that predict the log grade based on the properties measured by the X-ray LogScanner. The study showed that 77-83% of the logs were correctly sorted when using the scanner to sort logs into three groups according to the predicted grade of the center boards. After sawing the sorted logs, 67% of the boards had the correct grade. When scanning the same logs repeatedly, the relative standard deviation of the predicted grade was 12-20%. The study also showed that it is possible to sort out 10 and 16%, respectively, of the material into two groups with high quality logs, without changing the grade distribution of the rest of the material to any great extent
|
|
| 7. |
- Trygg, Johan, et al.
(författare)
-
2D wavelet analysis and compression of on-line industrial process data
- 2001
-
Ingår i: Journal of Chemometrics: SPECIAL ISSUE: Dedicated to Harald Martens-The Third Recipient of the Herman Wold Medal. Issue Edited by Lennart Eriksson, Torbjörn Lundstedt. - : Wiley. ; 15:4, s. 299-319
-
Tidskriftsartikel (refereegranskat)abstract
- In recent years the wavelet transform (WT) has interested a large number of scientists from many different fields. Pattern recognition, signal processing, signal compression, process monitoring and control, and image analysis are some areas where wavelets have shown promising results. In this paper, 2D wavelet analysis and compression of near-infrared spectra for on-line monitoring of wood chips is reviewed. We introduce a new parameter for outlier detection, distance to model in wavelet space (DModW), which is analogous to the residual parameter (DModX) used in principal component analysis (PCA) and partial least squares analysis (PLS). Additionally, we describe the wavelet power spectrum (WPS), the wavelet analogue of the power spectrum. The WPS gives an overview of the time-frequency content in a signal. In the example given, wavelets improved the detection of spectral shift and compressed data 1000-fold without degrading the quality of the 2D wavelet-compressed PCA model. The example concerned an industrial process-monitoring situation where near-infrared spectra are measured on-line on top of a conveyer belt filled with wood chips at a Swedish pulp plant.
|
|
| 8. |
- Trygg, Johan, et al.
(författare)
-
Vegetabile material, plants and a method of producing a plant having altered lignin properties
- 2012
-
Patent (populärvet., debatt m.m.)abstract
- The present invention is related to a set of genes, which when modified in plants gives altered lignin properties. The invention provides DNA construct such as a vector useful in the method of the invention. Further, the invention relates to a plant cell or plant progeny of the plants and wood produced by the plants according to the invention Lower lignin levels will result in improved saccharification for bio-refining and ethanol production and improved pulp and paper. Increased lignin levels will utilise lignin properties for energy production. The genes and DNA constructs may be used for the identification of plants having altered lignin characteristics as compared to the wild-type. According to the invention genes and DNA constructs may also be used as candidate genes in marker assisted breeding.
|
|
| 9. |
- Wallbäcks, Lars
(författare)
-
Multivariate data analysis of multivariate populations
- 2007
-
Ingår i: Chemometrics and Intelligent Laboratory Systems. - : Elsevier BV. - 0169-7439 .- 1873-3239. ; 86:1, s. 10-16
-
Tidskriftsartikel (refereegranskat)abstract
- For data that can be arranged in populations, multivariate data analysis of digitalized distributions is suggested as an alternative method to detect variations. This approach includes a representation of the data that avoids information destroying pre-processing such as averaging. The method is exemplified and discussed for both single variable distributions and multivariable distributions. A theoretical discussion is presented on its use with data from fibre measuring systems, time series and image analysis data. The method is suggested as either a complement or alternative to other types of data analysis and opens new possibilities for variation detection.
|
|
| 10. |
|
|
