New Perspectives for LVL Manufacturing from Wood of Heterogeneous Quality—Part. 1: Veneer Mechanical Grading Based on Online Local Wood Fiber Orientation Measurement

The grading of wood veneers according to their true mechanical potential is an important issue in the peeling industry. Unlike in the sawmilling industry, this activity does not currently estimate the local properties of production. The potential of the tracheid effect, which enables local fiber orientation measurement, has been widely documented for sawn products. A measuring instrument exploiting this technology and implemented on a peeling line was developed, enabling us to obtain the fiber orientation locally which, together with global density, allowed us to model the local elastic properties of each veneer. A sorting method using this data was developed and is presented here. It was applied to 286 veneers from several logs of French Douglas fir, and was compared to a widely used sorting method based on veneer appearance defects. The effectiveness of both grading approaches was quantified according to mechanical criteria. This study shows that the sorting method used (based on local fiber orientation and average density) allows for better theorical quality discrimination according to the mechanical potential. This article is the first in a series, with the overall aim of enhancing the use of heterogeneous wood veneers in the manufacturing of maximized-performance LVL by veneer grading and optimized positioning as well as material mechanical property modelization.

Evaluation of a Health-Management Course for Recently Settled Immigrants

This study aims to evaluate an intervention, consisting of nine weeks of health-management course, combined with social and working life orientation and language instruction for recently settled immigrants in Sweden. One hundred one participants in the intervention groups and 48 participants in the control group participated. The intervention consisted of a health management course combined with social and working life orientation and the control group participated in the regular local authority program for social and working life orientation. Measurement instruments were health-related quality of life (HRQoL) and registration of work rate. Several participants in the groups were in work, primarily in subsidized employment, after six months. Recently settled men were employed to a greater extent than the women, where poorer physical and mental health could be observed among women in this study. Participants in the intervention and the control groups had maintained HRQoL from pre-intervention to six months post-intervention. More studies investigating the participants experiences of the health-managing course but also more homogenous measurements in studies for recently settled immigrants are needed.

In-SEM micro-machining reveals the origins of the size effect in the cutting energy

High-precision metal cutting is increasingly relevant in advanced applications. Such precision normally requires a cutting feed in the micron or even sub-micron dimension scale, which raises questions about applicability of concepts developed in industrial scale machining. To address this challenge, we have developed a device to perform linear cutting with force measurement in the vacuum chamber of an electron microscope, which has been utilised to study the cutting process down to 200 nm of the feed and the tool tip radius. The machining experiments carried out in-operando in SEM have shown that the main classical deformation zones of metal cutting: primary, secondary and tertiary shear zones—were preserved even at sub-micron feeds. In-operando observations and subsequent structural analysis in FIB/SEM revealed a number of microstructural peculiarities, such as: a substantial increase of the cutting force related to the development of the primary shear zone; dependence of the ternary shear zone thickness on the underlaying grain crystal orientation. Measurement of the cutting forces at deep submicron feeds and cutting tool apex radii has been exploited to discriminate different sources for the size effect on the cutting energy (dependence of the energy on the feed and tool radius). It was observed that typical industrial values of feed and tool radius imposes a size effect determined primarily by geometrical factors, while in a sub-micrometre feed range the contribution of the strain hardening in the primary share zone becomes relevant.

Differential Alcohol Use Disparities by Sexual Identity and Behavior Among High School Students

Aims Sexual minority youth (SMY) use alcohol at disproportionate rates compared to their heterosexual peers. However, sexual orientation is multidimensional. Analyzing alcohol use disparities only by one dimension of sexual orientation may result in critical disparities being obscured. Methods Data from state and local versions of the Youth Risk Behavior Survey were pooled (2009–2017), resulting in a large, diverse sample (n = 201,671). Multivariable logistic regression models were used to analyze associations between sexual identity/sexual behavior and three alcohol use outcomes among sexually active youth: age at first drink, binge drinking and current drinking. Results SMY, when categorized by sexual identity and sexual behavior, reported greater alcohol use than their heterosexual peers, though the magnitude of these disparities varied by subgroup. Both those who identified as bisexual and those who reported sexual behavior with both males and females reported the greatest levels of alcohol use. Decomposition analysis revealed that youth whose reported sexual behavior was not aligned with stereotypical behavioral expectations based on their sexual identity had higher odds of current drinking and drinking before 13 years as compared to other youth. Conclusions Results highlight the need to incorporate multiple methods of sexual orientation measurement into substance use research. Interventions based solely on identity, rather than both identity and behavior, may not be sufficient; targeted research into the causes of alcohol use disparities is needed, especially for bisexual youth, youth whose sexual behavior and sexual identity are not stereotypically aligned, and youth who report a sexual identity of ‘not sure.’

Influence of wood anatomy on fiber orientation measurement obtained by laser scanning on five European species

In order to obtain high production rates of sawn timber, the sawmilling industry can use laser scanning, allowing knot detection and machine strength grading. In particular, laser scanners measure grain angle using the so-called tracheid effect on wood surface where an elliptic scattering of the laser light can be observed. This paper aims to describe the light scattering obtained by a laser beam projection on wood surface and to assess the accuracy of such fiber orientation measurement on five European species. Firstly, fiber orientation measurement error was assessed by rotating samples. Secondly, the description of the scattering effect was done considering ellipse axis ratios and areas. This was studied according to several parameters such as wood surface machining, moisture content, and orthotropic planes of symmetry. Fiber orientation measurement was successfully performed on all the tested species. The measurement error was below 1.6°, except for oak longitudinal–radial (LR) plane showing an error up to 3.1°. For most of the species, the error was higher in LR plane because of the influence of medullary rays. Despite the observation of major variabilities in laser light scattering, it was possible to measure the grain angles with a good accuracy for all investigated species.

A Synchronous Spin-Exchange Optically Pumped NMR-Gyroscope

Inertial navigation systems generally consist of timing, acceleration, and orientation measurement units. Although much progress has been made towards developing primary timing sources such as atomic clocks, acceleration and orientation measurement units often require calibration. Nuclear Magnetic Resonance (NMR) gyroscopes, which rely on continuous measurement of the simultaneous Larmor precession of two co-located polarized noble gases, can be configured to have scale factors that depend to first order only on fundamental constants. The noble gases are polarized by spin-exchange collisions with co-located optically pumped alkali-metal atoms. The alkali-metal atoms are also used to detect the phase of precession of the polarized noble gas nuclei. Here we present a version of an NMR gyroscope designed to suppress systematic errors from the alkali-metal atoms. We demonstrate rotation rate angle random walk (ARW) sensitivity of 16μHz/Hz and bias instability of ∼800 nHz.