Thermal and Irradiation Creep Behavior of a Titanium Aluminide in Advanced Nuclear Plant Environments

Titanium aluminides are well-accepted elevated temperature materials. In conventional applications, their poor oxidation resistance limits the maximum operating temperature. Advanced reactors operate in nonoxidizing environments. This could enlarge the applicability of these materials to higher temperatures. The behavior of a cast gamma-alpha-2 TiAl was investigated under thermal and irradiation conditions. Irradiation creep was studied in beam using helium implantation. Dog-bone samples of dimensions 10×2×0.2mm3 were investigated in a temperature range of 300°C to 500°C under irradiation, and significant creep strains were detected. At temperatures above 500°C, thermal creep becomes the predominant mechanism. Thermal creep was investigated at temperatures up to 900°C without irradiation with samples of the same geometry. The results are compared with other materials considered for advanced fission applications. These are a ferritic oxide-dispersion-strengthened material (PM2000) and the nickel-base superalloy IN617. A better thermal creep behavior than IN617 was found in the entire temperature range. Up to 900°C, the expected 104 hour stress rupture properties exceeded even those of the ODS alloy. The irradiation creep performance of the titanium aluminide was comparable with the ODS steels. For IN617, no irradiation creep experiments were performed due to the expected low irradiation resistance (swelling, helium embrittlement) of nickel-base alloy

Spectroscopy of D-type asteroids

We have performed a spectroscopic survey of 19 D-type asteroids. Comparison with previous photometry shows excellent agreement. Although the majority have similar colors to cometary nuclei, no cometary emission bands were present in any of the spectra. Absorption bands sporadically appearing were apparently due to stellar objects, and no features inherent to the asteroids were observed

Design for me?

In this paper, as a generative contrast to the notion of design “for all”, we present and discuss the potential benefits of a design “for me” approach, where the design process from the starts from, and initially is targeted at, just one person. Given many things developed for a user group or a constructed average user, in this text we describe starting from design for a single user as an alternative approach for achieving useful and useworthy designs. We provide an example from the development of an assistive device as the starting point and discuss how and why this alternative approach should be of interest for everyone interested in usability

Development of Norway spruce, Douglas fir, beech and Scots pine with a shelter of hybrid larch

"Development of Norway spruce, Douglas fir beech and Scots pine with a larch shelter wood" is a report written by Per-Olof Magnusson. The thesis is a compulsory part of forest engineer program at "Skogsmästarskolan", SLU, Skinnskatteberg, Sweden. The purpose of this report is to describe and evaluate an experiment with hybrid larch (Larix x eurolepis) as shelter wood, and different tree species growth and survival depending on the density of the shelter wood. The experiment is conducted by southern Swedish forest research centre, faculty of forestry, SLU in Alnarp. The hybrid larch ought to be an interesting alternative to birch (Betula sp.) as shelterwood on suitable sites in southern Sweden. It outgrows both grass and other vegetation quickly and is regarded to be a good shelter tree to shadow tolerant tree species as beech and spruce. The timber prices is approximately the same as for spruce, but straight, knot free wood can have same prizes as pine. About 2000 hybrid larches per ha were planted 1974. After four thinnings and one storm there's now standing 230 trees in the dense shelter and 145 in the sparse shelter. Below the shelters and on one open area spruce (Picea abies) were planted in 1990. Due to heavy gracing a fence was built spring 1993. Beech (Fagus sylvatica), douglas fir (Psedotsuga menziesii) and pine (Pinus sylvestris) and spruce were planted in the tree areas, a dense shelter, a sparse shelter and an open area adjacent to the shelters. Since these results is based on only one experiment no final conclusions can be made, but the results give a hint on how the different tree species react on the shelterwood density. As expected the growth of all the different tree species increase with lesser amount of shelter wood (Fig. 2-3). The pines bellow the shelter woods were all killed by insects or by a combination of competition from the shelter and insects, at an early stage. The survival lies between 72 and 97 % for all the tree species except for the Douglas-fir. The lowest survival for Douglas-fir was below the sparse shelter wood (36 %). Overall it looks like the mortality is greater below the sparse shelter wood but the most probable reason for this is that the fence on this location was broken in a couple of places and roe deer and elk has got in and graced. You could probably see more obvious trends of survival if the experiment had been placed in a more frost affected area. One could also speculate if the spruce and beech would have a greater mortality without the shelter wood since grass grew thick amongst the plants.Syftet med detta examensarbete är att beskriva och redovisa ett försök med hybridlärk som skärmträd över planterad tall, gran, bok och douglasgran. samt att redovisa de olika trädslags tillväxt och överlevnad i olika täta skärmar. Hybridlärken borde vara ett intressant alternativ som skärmträd på lämpliga marker i södra Sverige. Den växer snabbt ifrån både ogräs och lövsly och anses vara ett mycket bra amträd åt skuggtåliga trädslag som bok och gran. 1974 planterades 2000 hybridlärkar per hektar på ”OD Krooks donations” mark i närheten av Klippan, Skåne. Efter fyra gallringar samt två stormar återstod 173 respektive 147 träd per hektar på två försöksområden. Under dessa skärmar, samt på en kalyta planterades gran (kallad bef. gran i texten). Då dessa granar betades kraftigt sattes ett viltstängsel upp våren 1993, samtidigt planterades bok, douglasgran, tall och en ny generation gran. Tillväxt, skadefrekvens och dödlighet bland dessa plantor har mätts kontinuerligt och har i här sammanställts och utvärderats. Alla tallplantor under de båda skärmarna har dött, dels på grund av insekter, troligen lärksäcksmalen, som fallit ner från lärkarna, samt på grund av kraftig konkurrens från kruståtel. Överlevnaden bland de andra trädslagen ligger på mellan 56 och 97 % (tabell 1). Under den glesa skärmen är överlevnaden lägst, men det beror troligtvis på att viltsängslet vid några tillfällen varit sönder här så att viltet har haft det lättare att komma in här. I kontrast till detta har en något större andel självföryngrade plantor lyckats etablera sig under den glesa skärmen. De självföryngrade plantorna är av andra trädslag och så små att de sällan kommer att ingå i framtidsbeståndet. I tabell 1 ser skadefrekvensen hög ut men de flesta av skadorna är gamla eller relativt ofarliga och resulterar i de flesta fall i en mindre tillväxtförlust. Höjdtillväxten ökar markant utan skärm. Detta gäller i högre grad för barrplantorna än för bokplantorna. Hade försöket placerats i ett mer frostdrabbat område hade man troligtvis sett tydligare trender för överlevnad, man kan också spekulera ifall så många gran och bokplantor hade överlevt utan skärmarna eftersom gräset växte tätt mellan plantorna. Skärmar av lärk (hybridlärk) med de tätheter som använts i försöket i Vedby (grundyta på mellan 10 och 15 m2/ha) passar bra över bok. För douglasgran har höjdtillväxten sänkts med ca 25% och för gran ca 40% jämfört med kalytan. Att plantera tall under skärm av lärk avrådes bestämt ifrån

Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering

In this work, amorphous thin films in Mg-Si-O-N system were prepared in order to investigate the dependence of optical and mechanical properties on Mg composition. Reactive RF magnetron co-sputtering from magnesium and silicon targets were used for the deposition of Mg-Si-O-N thin films. Films were deposited on float glass, silica wafers and sapphire substrates in an Ar, N2 and O2 gas mixture. X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, spectroscopic ellipsometry, and nanoindentation were employed to characterize the composition, surface morphology, and properties of the films

Philosophy and updating of the asteroid photometric catalogue

The Asteroid Photometric Catalogue now contains photometric lightcurves for 584 asteroids. We discuss some of the guiding principles behind it. This concerns both observers who offer input to it and users of the product

Blood alcohol concentration at 0.06 and 0.10% causes a complex multifaceted deterioration of body movement control.

Alcohol-related falls are recognized as a major contributor to the occurrence of traumatic brain injury. The control of upright standing balance is complex and composes of contributions from several partly independent mechanisms such as appropriate information from multiple sensory systems and correct feedback and feed forward movement control. Analysis of multisegmented body movement offers a rarely used option for detecting the fine motor problems associated with alcohol intoxication. The study aims were to investigate whether (1) alcohol intoxication at 0.06 and 0.10% blood alcohol concentration (BAC) affected the body movements under unperturbed and perturbed standing; and (2) alcohol affected the ability for sensorimotor adaptation. Body movements were recorded in 25 participants (13 women and 12 men, mean age 25.1 years) at five locations (ankle, knee, hip, shoulder, and head) during quiet standing and during balance perturbations from pseudorandom pulses of calf muscle vibration over 200s with eyes closed or open. Tests were performed at 0.00, 0.06, and 0.10% BAC. The study revealed several significant findings: (1) an alcohol dose-specific effect; (2) a direction-specific stability decrease from alcohol intoxication; (3) a movement pattern change related to the level of alcohol intoxication during unperturbed standing and perturbed standing; (4) a sensorimotor adaptation deterioration with increased alcohol intoxication; and (5) that vision provided a weaker contribution to postural control during alcohol intoxication. Hence, alcohol intoxication at 0.06 and 0.10% BAC causes a complex multifaceted deterioration of human postural control

Police officer involved shootings – retrospective study of situational characteristics

The study analyzed the situational characteristics of 112 incidents where police used firearms to handle high threat situations. Most shooting incidents emanated from usually uneventful tasks, e.g., handling burglaries or disturbances. The assailants were commonly armed with firearms (26%), sharp (27%) or blunt objects (10%). The incidents were regularly short-lasting (in 39% were shots fired ≤3 s from threat emerged) and occurred at short distances (in 42% at distances ≤3 m). Predominantly, the first responders had to address the situation and did so with warning shots or, equally common, with fire-for-effect shots (40%) or a combination thereof. Psychological stress was manifested as feelings of panic at some point and as motor skill alterations, e.g., firing without using sights and with one hand only. Analysis of these incidents shows that all field duty police officers should receive training in handling potentially life-threatening, sudden, close-range attacks

Lipocalin-2 is associated with FGF23 in WNT1 and PLS3 osteoporosis

BackgroundThe pathogenic mechanisms of early-onset osteoporosis caused by WNT1 and PLS3 mutations are incompletely understood and diagnostic biomarkers of these disorders are limited. Recently, lipocalin-2 has been recognized as an osteokine involved in bone development and homeostasis. However, the role of lipocalin-2 in WNT1 and PLS3 osteoporosis is unknown. ObjectiveWe aimed to investigate if plasma lipocalin-2 could be utilized as a biomarker for WNT1 and PLS3 osteoporosis and to evaluate the association between lipocalin-2 and other parameters of bone metabolism. MethodsWe measured plasma lipocalin-2 in 17 WNT1 and 14 PLS3 mutation-positive patients and compared them to those of 34 mutation-negative (MN) healthy subjects. We investigated possible associations between lipocalin-2 and several bone biomarkers including collagen type I cross-linked C-telopeptide (CTX), alkaline phosphatase (ALP), type I procollagen intact N-terminal propeptide (PINP), intact and C-terminal fibroblast growth factor 23 (FGF23), dickkopf-1 (DKK1) and sclerostin as well as parameters of iron metabolism (iron, transferrin, transferrin saturation, soluble transferrin receptor and ferritin). ResultsWe found no differences in plasma lipocalin-2 levels in WNT1 or PLS3 patients compared with MN subjects. However, lipocalin-2 was associated with C-terminal FGF23 in WNT1 patients (r=0.62; p=0.008) and PLS3 patients (r=0.63, p=0.017), and with intact FGF23 in PLS3 patients (r=0.80; pPeer reviewe