48 research outputs found
Distribution, characteristics and potential of biomass-dense thinning forests in Sweden
Understanding the characteristics of unutilized biomass resources, such as small-diameter trees from biomass-dense thinning forests (BDTF) (non-commercially-thinned forests), can provide important information for developing a bio-based economy. The aim of this study was to describe the areal distribution, characteristics (biomass of growing stock, tree height, etc.) and harvesting potential of BDTF in Sweden. A national forest inventory plot dataset was imported into a geographical information system and plots containing BDTF were selected by applying increasingly stringent constraints. Results show that, depending on the constraints applied, BDTF covers 9-44% (2.1-9.8 M ha) of the productive forest land area, and contains 7-34% of the total growing stock (119-564 M OD t), with an average biomass density of 57 OD t ha^-1. Of the total BDTF area, 65% is located in northern Sweden and 2% corresponds to set-aside farmlands. Comparisons with a study from 2008 indicate that BDTF area has increased by at least 4% (about 102 000 ha), in line with general trends for Sweden and Europe. Analyses revealed that the technical harvesting potential of delimbed stemwood (over bark, including tops) from BDTF ranges from 3.0 to 6.1 M OD t yr^-1 (7.5 to 15.1 M m^3 yr^-1), while the potential of whole-tree harvesting ranges from 4.3 to 8.7 M OD t yr^-1 (10.2 to 20.6 M m3 yr^-1) depending on the scenario considered. However, further technological developments of the harvest and supply systems are needed to utilize the full potential of BDTF
Extension of thermonuclear functions through the pathway model including Maxwell-Boltzmann and Tsallis distributions
The Maxwell-Boltzmannian approach to nuclear reaction rate theory is extended
to cover Tsallis statistics (Tsallis, 1988) and more general cases of
distribution functions. An analytical study of respective thermonuclear
functions is being conducted with the help of statistical techniques. The
pathway model, recently introduced by Mathai (2005), is utilized for
thermonuclear functions and closed-form representations are obtained in terms
of H-functions and G-functions. Maxwell-Boltzmannian thermonuclear functions
become particular cases of the extended thermonuclear functions. A brief review
on the development of the theory of analytic representations of nuclear
reaction rates is given.Comment: 16 pages, LaTe
The Cosmic-Ray Proton and Helium Spectra measured with the CAPRICE98 balloon experiment
A new measurement of the primary cosmic-ray proton and helium fluxes from 3
to 350 GeV was carried out by the balloon-borne CAPRICE experiment in 1998.
This experimental setup combines different detector techniques and has
excellent particle discrimination capabilities allowing clear particle
identification. Our experiment has the capability to determine accurately
detector selection efficiencies and systematic errors associated with them.
Furthermore, it can check for the first time the energy determined by the
magnet spectrometer by using the Cherenkov angle measured by the RICH detector
well above 20 GeV/n. The analysis of the primary proton and helium components
is described here and the results are compared with other recent measurements
using other magnet spectrometers. The observed energy spectra at the top of the
atmosphere can be represented by (1.27+-0.09)x10^4 E^(-2.75+-0.02) particles
(m^2 GeV sr s)^-1, where E is the kinetic energy, for protons between 20 and
350 GeV and (4.8+-0.8)x10^2 E^(-2.67+-0.06) particles (m^2 GeV nucleon^-1 sr
s)^-1, where E is the kinetic energy per nucleon, for helium nuclei between 15
and 150 GeV nucleon^-1.Comment: To be published on Astroparticle Physics (44 pages, 13 figures, 5
tables
Weak Lensing from Space I: Instrumentation and Survey Strategy
A wide field space-based imaging telescope is necessary to fully exploit the
technique of observing dark matter via weak gravitational lensing. This first
paper in a three part series outlines the survey strategies and relevant
instrumental parameters for such a mission. As a concrete example of hardware
design, we consider the proposed Supernova/Acceleration Probe (SNAP). Using
SNAP engineering models, we quantify the major contributions to this
telescope's Point Spread Function (PSF). These PSF contributions are relevant
to any similar wide field space telescope. We further show that the PSF of SNAP
or a similar telescope will be smaller than current ground-based PSFs, and more
isotropic and stable over time than the PSF of the Hubble Space Telescope. We
outline survey strategies for two different regimes - a ``wide'' 300 square
degree survey and a ``deep'' 15 square degree survey that will accomplish
various weak lensing goals including statistical studies and dark matter
mapping.Comment: 25 pages, 8 figures, 1 table, replaced with Published Versio
De invloed van het voerregime tijdens de opfok op spermaproduktie, spermakwaliteit en beenwerk van stieren
Voor het bepalen van de vleesproduktiegeschiktheid van toekomstige k.i.-stieren is het misschien beter om deze tijdens de opfok volgens een mestschema te voeren. In dit onderzoek onder 120 stierkalveren is nagegaan of dit invloed had op de spermaproduktie, spermakwaliteit en het beenwerk van de stiere