269 research outputs found
Measurement of the Density of Base Fluids at Pressures 0.422 to 2.20 Gpa
The influence of pressure on the density of six base fluids is experimentally studied for a range of pressures from 0.422 to 2.20 GPa. An important parameter used to describe the results is the change in relative volume with change in pressure dv sub r/dp. For pressures less than the solidification pressure (p ps) a small change in pressure results in a large change in dv sub r/ps. For pressures greater than the solidification pressure (p ps) there is no change in dv sub r/dp with changing pressure. The solidification pressures of the base fluids varies considerably, as do the slopes that the experimental data assumes for p ps. A new formula is developed that describes the effect of pressure on density in terms of four constants. These constants vary for the different base fluids tested
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
On extended thermonuclear functions through pathway model
The major problem in the cosmological nucleosynthesis is the evaluation of
the reaction rate. The present scenario is that the standard thermonuclear
function in the Maxwell-Boltzmann form is evaluated by using various
techniques. The Maxwell-Boltzmannian approach to nuclear reaction rate theory
is extended to cover Tsallis statistics (Tsallis, 1988) and more general cases
of distribution functions. The main purpose of this paper is to investigate in
some more detail the extended reaction probability integral in the equilibrium
thermodynamic argument and in the cut-off case. The extended reaction
probability integrals will be evaluated in closed form for all convenient
values of the parameter by means of residue calculus. A comparison of the
standard reaction probability integrals with the extended reaction probability
integrals is also done.Comment: 21 pages, LaTe
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Internal spin structure of the proton from high energy polarized e-p scattering
A review is given of experimental knowledge of the spin dependent structure functions of the proton, which is based on inclusive high energy scattering of longitudinal polarized electrons by longitudinally polarized protons in both the deep inelastic and resonance regions, and includes preliminary results from our most recent SLAC experiment. Implications for scaling, sum rules, models of proton structure, and the hyperfine structure interval in hydrogen are given. Possible future directions of research are indicated
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
Omnidispersible poly(ionic liquid)-functionalized cellulose nanofibrils : surface grafting and polymer membrane reinforcement
De metapodia als voorspellers van formaat en gewicht bij runderen = The metapodia as predictors of size and weight in cattle
Verslag van een onderzoek naar het verband tussen de grootte van deze botten (homoloog met onze middenvoetbeentjes) als maat voor de grootte en het levend gewicht van runderen, op grond van waarnemingen bij stiertjes (Nederlands zwartbont en roodbont en Jersey). Deze botten zijn vaak de enige botten die bij archeologische vondsten intakt worden aangetroffen. Kennis van een dergelijk verband is daarom met name van belang om een voorstelling te kunnen maken van de praehistorische landbouwkundige situati
WIMP direct detection overview
This review on weakly interacting massive particle (WIMP) dark matter direct
detection focuses on experimental approaches and the corresponding physics
basics. The presentation is intended to provide a quick and concise
introduction for non-specialists to this fast evolving topic of astroparticle
physics.Comment: 13 pages, 6 figures, invited review for the Proc. XXth Int. Conf.
Neutrino Physics and Astrophysics, May 25-30, 2002, Munich, Germany; version
includes correction of typo in eqn.2; to appear in Nucl. Phys. B Proc. Supp
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
Future High Energy Neutrino Telescopes
This talk summarizes the main physics goals and basic methods of telescopes
for high energy neutrinos. It reviews the present status of deep underwater
telescopes and sketches the ICECUBE project as an example for a cube kilometer
detector. It is suggested to develop techniques for radio and acoustic
detection hand in hand with big optical arrays. These large arrays should be
complemented by medium-size detectors in the Megaton range.Comment: Talk given at the Int.Conf.on Neutrino Physics and Astrophysics,
Sudbury 2000, 8 pages, 7 figure
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