91 research outputs found
Design criteria of the bolometer diagnostic for steady-state operation of the W7-X stellarator
A bolometric diagnostic system with features necessary for steady-state operation in the superconducting stellarator W7-X was designed. During a pulse length of 1800 s with an ECRH (electron cyclotron resonance heating) power of 10 MW, the components suffer not only from a large thermal load but also from stray radiation of the nonabsorbed isotropic microwaves. This paper gives an overview of the technical problems encountered during the design work and the solutions to individual problems to meet the special requirements in W7-X, e.g., component thermal protection, detector offset thermal drift suppression, as well as a microwave shielding technique. © 2010 American Institute of Physic
Group polarization effect on decisions by selected Kenyan secondary school disciplinary panels
This study investigated social group phenomenon of group polarization effects on disciplinary hearing decisions in
selected Kenyan secondary school. The participants were 78 school personnel (females = 42%and males 58%) from ten
secondary schools with both unisex (n = 39) and co-educational schools (n = 39). Both quantitative and qualitative data
were collected and analyzed. The results suggested group polarization effects in disciplinary hearing decisions, in that
there were shifts from pre to post-disciplinary hearing decisions. Persuasive arguments and social comparisons
significantly influenced group polarization decisions.Department of HE and Training approved lis
Impacts of soil conditions and light availability on natural regeneration of Norway spruce Picea abies (L.) H. Karst. in low-elevation mountain forests
& Key message Natural regeneration of P. abies (L.) H. Karst. may reach high densities in lower mountain elevations. The
highest densities were found in sites with moderate light availability, with low pH, and not near the riverbank. However,
age-height classes differed in the predicted magnitude of response, but were consistent in response directions. Mosses and
understory species typical of coniferous forests were positively correlated with regeneration density.
& Context Norway spruce Picea abies (L.) H. Karst. in Central Europe is at risk under climate change scenarios, particularly in
mountain regions. Little is known about the impact of environmental factors on the natural regeneration of P. abies in lowelevation mountain forests.
& Aims We aimed to assess impacts of distance from the riverbank, soil pH, and light availability on natural P. abies regeneration.
We hypothesized that (1) natural P. abiesregeneration would depend on light availability and soil pH and (2) there are understory
plant species which may indicate the microsites suitable for natural regeneration of P. abies.
& Methods The study was conducted in the Stołowe Mountains National Park (SW Poland, 600–800 m a.s.l.). We established 160
study plots (25 m2
) for natural regeneration, light availability, soil pH, and understory vegetation assessment
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Bark beetles in the Tatra Mountains. International research 1998-2005 - an overview
This paper is a review of fundamental information on bark beetles and their interactions with several predisposing
factors (air pollution, drought/temperature interactions, windthrows, management activities) that are thought to contribute
to the outbreaks in the High Tatra Mountains.
The findings of many research projects indicate that the impact of air pollution on bark beetle populations is
indirect and complex and that the disturbances in the physiology and natural resistance of trees may be of crucial
importance to bark beetle population dynamics. An active forest protection approach is needed to be applied to the
secondary Norway spruce forests affected in the past by human activity.
Bark beetle populations in natural and near-natural forests (mainly in the upper montane zone) are regulated
by natural mechanisms; bark beetles are therefore a natural factor contributing to forest development, including the
transition of future generations of spruce
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