Norwegian Institute of Wood Technology

Bokanmeldelse av: Dagfinn Skre 2025 The Northern Routes to Kingship. A History of Scandinavia AD 180–550 Routledge, London og New York. 574 s. ISBN: 9781138831384

Advances in computing and data have transformed seismic analysis from code-calibrated approximations toward performance-based verification, often anchored in nonlinear dynamics [...]

An extensive amount of research on noise has been conducted regarding traditional passive and active electronic devices. Being new passive electronic devices, memristors still lack systematic noise analysis and measurements in the literature. In this paper, we propose the measurement of the signal-to-noise ratio, the noise figure, the noise power spectral density in both a memristor as a single device and in a memristor-based crossbar structure, and the bandwidth. The results show that memristor devices' behavior under the influence of noise can be analyzed by relying on some strong existing assumptions based on linear circuits where the memristor device is treated instantaneously as a linear resistor, a voltage-driven memristor device is modeled as a voltage source in series with a noiseless resistor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{R}$</tex> with uniform white power spectral density, and the root mean square voltage of the noise is equivalent to the standard deviation of the zero-mean Gaussian PDF governing the thermal noise. This experiment paves the way for in-depth memristor noise investigations that could lead to the derivation of a generalized noise model tailor-made for memristor devices.

Timber structures are susceptible to sound propagation problems. The issue can be mitigated by decoupling structural components at connections level by means of polyurethane soundproofing interlayers. These layers are much softer than timber but, at the same time, they are characterized by higher friction coefficients. In this paper, an experimental investigation is carried out to characterize the mechanical behavior of insulated screw connections assessing the implications of the soundproofing layer use. Different interlayers, screw inclination angles and setups are considered. The load–slip behavior is studied, and a proper empirical model, suitable for performing push-over analysis of buildings involving soundproofed connections, is derived. The essential design parameters, namely the slip modulus, the strength and ductility, are determined and compared with existing models predictions, thus testing their accuracy. Substantial reductions in terms of stiffness, load-carrying capacity and ductility are observed in soundproofed connections.

The increasing use of timber structures worldwide has brought attention to the challenges posed by their lightweight nature, making them more prone to vibrations than more massive structures. Consequently, significant research efforts have been dedicated to understanding and mitigating vibrations in timber structures, while scientific committees strive to establish suitable design regulations. This study aims to classify and identify the main research themes related to timber structure vibrations and highlight future research needs and directions. A bibliometric-based selection process briefly introduces each research topic, presenting the latest findings and proposals for vibration design in timber structures. The paper emphasizes the key outcomes and significant contributions to understanding and addressing vibration issues in timber structures. These findings serve as valuable guidance for researchers, designers, and regulatory bodies involved in designing and assessing timber structures subjected to vibrations.

In this study, the potential application of a two-component phenol-resorcinol-formaldehyde adhesive for on-site reinforcement of glued laminated timber (GLT) and a recovered spruce beam was investigated. Different spread rates (500 -2000 g/m 2 ), means of pressurization of the bond lines (clamps, screws and the reinforcements own mass) were applied to establish bond lines between the substrate to be reinforced and the reinforcements, GLT and plywood (PLW). The surface conditions (not planed, partly coated/ sanded, varying surface moisture content) were chosen to resemble situations that might be encountered during on-site reinforcement. The bond lines of two of the 11 different combinations fulfilled the required shear strength according to EN 14080. The investigations show that thicker bond lines and low pressure on the bond lines result in lower bond strength. Coating and partial removal of the coating by sanding are expected to have amplified the effect of the chemically weak boundary layer. Bond lines between materials with similar surfaces yield higher shear strength compared to bond lines between materials with differing surfaces.

Introduction Woods are energy efficient and carbon-neutral building materials; however we need more scientific knowledge of their chemical emissions and the health impacts. The aim of this study was to investigate whether exposure to volatile organic compounds (VOCs) from pine may increase mucous membrane symptoms from eyes and respiratory airways compared to exposure to VOCs from spruce. Methods The study was carried out with a randomized, double-blind, cross-over experimental design. The study was approved by the Regional Medical Ethics Committee. The intervention treatment was an exposure by VOCs from pine for 2 hours, while the control exposure was VOCs from spruce. 30 persons participated in the study, 16 men and 14 women. They were all young adult non-smokers. Two persons had former moderate allergic symptoms. The exposures were measured with the mass spectrometer “PTR-TOF-MS”. The health indicators were measured before and after the treatment. The questionnaire used was the Örebro questionnaire, the lung functions were measured with “Micro medical spiro usb”. Measurements of the VOCs revealed that the exposure was primarily from monoterpenes. The mean concentration of monoterpenes from pine was 163.4 ppb while the corresponding concentration from spruce was 1.0 ppb. T-test was used to unveil a statistical significant difference between change in health effects between intervention and control condition. Results The change of subjective symptoms was almost similar in control and intervention conditions. No statistical significant differences were revealed. The spirometry analyses, PEF, MEF50 and FVC, showed no statistically significant changes. However, measurements of the FEV1 showed that upon the exposure of pine no change occurred, while during exposure to spruce a small negative change was detected. Conclusions The results showed no increased mucous membrane symptoms and respiratory airways symptoms during exposure of VOCs to pine compared to spruce.

Various oils can be used to lower the equilibrium moisture content and increase the service life of Scots pine wood products. The aim of this study was to investigate effects of the lateral wood zone on the brown rot resistance of untreated and linseed oil-impregnated Scots pine wood in a laboratory test (EN 113). Significant differences were found in the mean mass losses of treated and untreated specimens taken from three lateral heartwood zones, but not between specimens taken from sapwood. The treatment had no significant effect on sapwood, although it seems to have some positive effect on the durability of heartwood, apparently due to interactive effects with the high extractives contents of heartwood.

I dette essayet unders&oslash;ker jeg spr&aring;kets rolle i oppdagende skriving, og forholdet mellom skrive&shy;ferdighet og evne til &aring; forst&aring;. Jeg utforsker spr&aring;kets virkelighetsnatur som vei mellom uformet anelse og formet tekst ved &aring; g&aring; inn i det vi kan kalle &ldquo;skrivingens flyktige &oslash;yeblikk&rdquo; &ndash; akkurat der det jeg har p&aring; hjertet tar form som ord. Her representerer ikke spr&aring;ket noe jeg allerede kjenner, skrivingen er oppdagelsen av det jeg skriver. En utfordring er at teksten som tar form har en ten&shy;dens til &aring; overskygge den enn&aring; uformede anelsen. Hvordan gi form uten &aring; miste ber&oslash;ringen med det forml&oslash;se? Jeg ser det &aring; skrive som &aring; s&oslash;ke en plass i m&oslash;tet mellom forml&oslash;shetens &aring;penhet og formenes forpliktende logikk. Perspektivet jeg presenterer er inspirert av den japanske kamp&shy;kunsten aikido, der tomhet og form er essensielle kategorier.

Grades derived from visual assessments of sawn timber are determined by the worst part of each piece. Since grade varies longitudinally in timber, grade yield will decrease if the average length of timber increases. The variation in grade is caused by longitudinal variation in knot properties and other features as they appear on the sawn surface taken into account during grading. The objective of this study is to describe and analyze this variation in Piceaabies.