MULTIDIMENSIONAL STRENGTH PROPERTIES IN CLEAR WOOD SAMPLES OF CULTIVATED NORWAY SPRUCE PRO LIGNO

Abstract: Variatio

Bearbeiding og modifisering av tre og trebaserte materialer

Fra Institutt for skogfag. Kompendiet omfatter størstedelen av pensum i emne TT 202 - høsten 1998

Bearbeiding og modifisering av tre og trebaserte materialer

Fra Institutt for skogfag. Kompendiet omfatter størstedelen av pensum i emne TT 202 - høsten 1998

Osp som byggemateriale

publishedVersio

Osp - et treslag med mange anvendelsesmuligheter

publishedVersio

Differences in basic density and strength properties of Milicia excelsa, Maesopsis eminii, Cynometra alexandri and Celtis gomphophylla from Budongo forest, Uganda

No Abstrac

Cost and performance management in the sawmilling industry

Joint costs are costs which cannot be readily identified with individual products. They are especially prominent in extractive, agricultural and chemical industries. In this article we consider methods used by the Norwegian sawmilling industry to allocate joint costs. A survey of joint cost accounting systems in use in Norwegian sawmills was carried out using structured interviews. In order to analyze the results from the interviews we conducted a Cross Case Analysis. According to the results Norwegian sawmills do not allocate joint costs, except from some ad-hoc methods inapplicable for joint cost allocation to products. There are several reasons for this. The problem is perceived as difficult to solve and many of the respondents consider the benefit as limited. There are shortcomings in existing joint cost allocation systems, and finally, there is a lack of interest and knowledge about cost accounting

Image Quality and Detectability in Siemens Biograph PET/MRI and PET/CT Systems - A Phantom study

Background The technology of modern positron emission tomography (PET) systems continuously improving, and with it the possibility to detect smaller lesions. Since first introduced in 2010, the number of hybrid PET/magnetic resonance imaging (MRI) systems worldwide is constantly increasing. It is therefore important to assess and compare the image quality, in terms of detectability, between the PET/MRI and the well-established PET/computed tomography (CT) systems. For this purpose, a PET image quality phantom (Esser) with hot spheres, ranging from 4 to 20 mm in diameter, was prepared with fluorodeoxyglucose and sphere-to-background activity concentrations of 8:1 and 4:1, to mimic clinical conditions. The phantom was scanned on a PET/MRI and a PET/CT system for both concentrations to obtain contrast recovery coefficients (CRCs) and contrast-to-noise ratios (CNRs), for a range of reconstruction settings. The detectability of the spheres was scored by three human observers for both systems and concentrations and all reconstructions. Furthermore, the impact of acquisition time on CNR and observer detectability was investigated. Results Reconstructions applying point-spread-function modeling (and time-of-flight for the PET/CT) yielded the highest CRC and CNR in general, and PET/CT demonstrated slightly higher values than PET/MRI for most sphere sizes. CNR was dependent on reconstruction settings and was maximized for 2 iterations, a pixel size of less than 2 mm and a 4 mm Gaussian filter. Acquisition times of 97 s (PET/MRI) and 150 s (PET/CT) resulted in similar total net true counts. For these acquisition times, the smallest detected spheres by the human observers in the 8:1 activity concentration was the 6-mm sphere with PET/MRI (CNR = 5.6) and the 5-mm sphere with PET/CT (CNR = 5.5). With an acquisition time of 180 s, the 5-mm sphere was also detected with PET/MRI (CNR = 5.8). The 8-mm sphere was the smallest detected sphere in the 4:1 activity concentration for both systems. Conclusion In this experimental study, similar detectability was found for the PET/MRI and the PET/CT, although for an increased acquisition time for the PET/MRI