4,674 research outputs found
Inhibited 1,1,1-trichloroethane replaces trichloroethylene for degreasing
In fight against air pollution inhibited TCE /1,1,1-trichloroethane/ is effective substitute for trichloroethylene in degreasing plants. This chemical has only slight photochemical activity and causes little eye irritation. TCE is less toxic than trichloroethylene and can withstand production loads and conditions, or long term storage, without degradation
Calibration and testing of a TLD dosemeter for area monitoring
The response of a TLD-600/TLD-700 area dosemeter has been characterized in neutron fields around the 590 MeV cyclotron ring at the Paul Scherrer Institute (PSI). The dosemeter is based on a cylindrical paraffin moderator with three of each type of TLD chip at the centre, and is intended to use for area monitoring around accelerator facilities. The dosemeter is calibrated in terms of ambient dose equivalent using a non-moderated 252Cf neutron source. The ambient dose equivalent response has been tested in five locations where the neutron fields and dose rates have been well characterized by Bonner sphere spectrometer and active neutron monitor measurements. The different spectrum shapes and dose rates in the five locations permit the comparison of the behavior of the active and passive dosemeters in these neutron field
Soft Photoproduction Physics
Several topics of interest in soft photoproduction physics are discussed.
These include jet universality issues (particle flavour composition), the
subdivision into event classes, the buildup of the total photoproduction cross
section and the effects of multiple interactions.Comment: 10 pages, LaTeX2e, no figures, to appear in the proceedings of the
Durham Workshop on HERA Physics, ``Proton, Photon and Pomeron Structure'',
17--23 September 1995, Durham, U.
Has the QCD RG-Improved Parton Content of Virtual Photons been Observed?
It is demonstrated that present and DIS ep data on the structure of
the virtual photon can be understood entirely in terms of the standard `naive'
quark--parton model box approach. Thus the QCD renormalization group (RG)
improved parton distributions of virtual photons, in particular their gluonic
component, have not yet been observed. The appropriate kinematical regions for
their future observation are pointed out as well as suitable measurements which
may demonstrate their relevance.Comment: 24 pages, LaTeX, 5 figure
Color-Octet Charmonium Production in Top Quark Decays
We calculate the direct production rate of in top quark decays. The
color-octet production via is shown to
have a large branching ratio of order , which is over an
order of magnitude higher than that of the color-singlet production
via or
followed by . This result can be used as a
powerful tool to test the importance of the color-octet mechanism in heavy
quarkonium production.Comment: 10 pages LaTex (2 figures in PS-file
Parameter uncertainty analysis for an operational hydrological model using residual-based and limits of acceptability approaches
Parameter uncertainty estimation is one of the major challenges
in hydrological modeling. Here we present parameter uncertainty analysis of
a recently released distributed conceptual hydrological model applied in the
Nea catchment, Norway. Two variants of the generalized likelihood uncertainty
estimation (GLUE) methodologies, one based on the residuals and the other on
the limits of acceptability, were employed. Streamflow and remote sensing
snow cover data were used in conditioning model parameters and in model
validation. When using the GLUE limit of acceptability (GLUE LOA) approach, a
streamflow observation error of 25 % was assumed. Neither the original
limits nor relaxing the limits up to a physically meaningful value yielded
a behavioral model capable of predicting streamflow within the limits in 100 % of the observations. As an alternative to relaxing the limits, the
requirement for the percentage of model predictions falling within the original
limits was relaxed. An empirical approach was introduced to define the degree
of relaxation. The result shows that snow- and water-balance-related
parameters induce relatively higher streamflow uncertainty than catchment
response parameters. Comparable results were obtained from behavioral models
selected using the two GLUE methodologies.</p
Resonant Production of Scalar Diquarks at the Next Generation Electron-Positron Colliders
We investigate the potential of TESLA and JLC/NLC electron-positron linear
collider designs to observe diquarks produced resonantly in processes involving
hard photons.Comment: 14 pages, 8 figures, coded in RevTEX, uses epsfi
Compilação e organização de parâmetros físicos de solos da Bacia do Pito Aceso para aplicação no sistema de modelagem hidrológica JAMS.
A escolha de um modelo hidrológico apropriado para uso em dada bacia deve considerar o acesso e custo do software, a viabilidade de aplicação, a disponibilidade e compatibilidade dos dados de entrada, bem como a familiaridade do usuário com os métodos de resolução. Devido às dificuldades e restrições de uso de alguns modelos de precipitação-vazão, a Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), no Centro Nacional de Pesquisa em Solos (CNPS), iniciou pesquisa visando à avaliação do uso do Sistema de Modelagem Adaptável de Jena (JAMS). Este estudo, fruto da parceria da Embrapa com a Universidade de Jena, busca a construção de um modelo precipitação-vazão que simule o escoamento superficial da microbacia do Córrego do Pito Aceso, inserida na Bacia do Rio Paraíba do Sul e localizada no município de Bom Jardim, região serrana do Rio de Janeiro - RJ. O objetivo deste trabalho foi compilar e organizar informações sobre modelagem hidrológica, trabalhos e teses publicadas sobre o local de estudo, bem como os dados disponíveis da microbacia, e artigos e teses sobre o sistema JAMS e suas aplicações. Foi possível identificar também as necessidades de novos dados e parâmetros a serem coletados
Multiple Interactions in Two-Photon Collisions
We compute cross sections for events where two pairs of partons scatter off
each other in the same reaction, giving rise to at least 3
high--{\mbox{}} jets. Unlike in {\mbox{}}\ collisions we find
the signal to lie well above the background from higher order QCD processes. If
the usual ``eikonaliztion" assumption is correct, the signal should be readily
observable at LEP2, and might already be detectable in data taken at TRISTAN.Comment: 8 pages, plain LaTeX, 2 figures (not included). A compressed PS file
of the entire paper, including figures, can be obtained via anonymous ftp
from ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-921.ps.
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