15 research outputs found
Improving the organization of work at selected workplacess in the company Krofian CZ spol. s r.o.
Improving the organization of work at selected workplacess in the company Krofian CZ spol. s r.o.
katedra: KVS; přílohy: CD ROM; rozsah: 46 s. (46 500 znaků)Analysis of the current state of the selected process in the company Krofian CZ spol. s r.o.. Deasing alternative solutions to improving the organization of work. Implementation of the accepted proposals and their rewiew.Analýza současného stavu vybraného procesu ve firmě Krofian CZ spol. s r.o.. Návrh variant řešení ke zlepšení organizace práce. Realizace přijatých návrhů a jejich zhodnocení
GRBAlpha: the smallest astrophysical space observatory -- Part 1: Detector design, system description and satellite operations
Aims. Since launched on 2021 March 22, the 1U-sized CubeSat GRBAlpha operates
and collects scientific data on high-energy transients, making it the smallest
astrophysical space observatory to date. GRBAlpha is an in-obit demonstration
of a gamma-ray burst (GRB) detector concept suitably small to fit into a
standard 1U volume. As it was demonstrated in a companion paper, GRBAlpha adds
significant value to the scientific community with accurate characterization of
bright GRBs, including the recent outstanding event of GRB 221009A. Methods.
The GRB detector is a 75x75x5 mm CsI(Tl) scintillator wrapped in a reflective
foil (ESR) read out by an array of SiPM detectors, multi-pixel photon counters
by Hamamatsu, driven by two separate, redundant units. To further protect the
scintillator block from sunlight and protect the SiPM detectors from particle
radiation, we apply a multi-layer structure of Tedlar wrapping, anodized
aluminium casing and a lead-alloy shielding on one edge of the assembly. The
setup allows observations of gamma radiation within the energy range of 70-890
keV with an energy resolution of ~30%. Results. Here, we summarize the system
design of the GRBAlpha mission, including the electronics and software
components of the detector, some aspects of the platform as well as the current
way of semi-autonomous operations. In addition, details are given about the raw
data products and telemetry in order to encourage the community for expansion
of the receiver network for our initiatives with GRBAlpha and related
experiments.Comment: Accepted for publication in Astronomy & Astrophysics, 9 pages, 10
figure
The peak-flux of GRB 221009A measured with GRBAlpha
The brightest gamma-ray burst ever observed, long-duration GRB 221009A, was
detected by GRBAlpha nano-satellite without saturation. We present light curves
of the prompt emission in 13 energy bands, from 80 keV to 950 keV, and perform
a spectral analysis to calculate the peak flux and peak isotropic-equivalent
luminosity. Since the satellite's attitude information is not available for the
time of this GRB, more than 200 incident directions were probed in order to
find the median luminosity and its systematic uncertainty. We found that the
peak flux in the keV range (observer frame) was
ph cms or
erg cms
and the fluence in the same energy range of the first GRB episode lasting 300
s, which was observable by GRBAlpha, was erg
cm or erg cm for
the extrapolated range of keV. We infer the isotropic-equivalent
released energy of the first GRB episode to be
erg in the
keV band (rest frame at ). The peak isotropic-equivalent luminosity in
the keV range (rest frame) was
erg s and the
bolometric peak isotropic-equivalent luminosity was
erg s (4 s
scale) in the keV range (rest frame). The peak emitted energy is
keV. Our measurement of
is consistent with the Yonetoku relation. It is
possible that, due to the spectral evolution of this GRB and orientation of
GRBAlpha at the peak time, the true values of peak flux, fluence,
, and are even higher. [abridged]Comment: 7 pages, 7 figures, 1 table, accepted for publication in Astronomy &
Astrophysic
The Four-Ring Birdcage Coil for 1H Imaging and 1H-Decoupled 31P MR Spectroscopy of the Human Head
Analysis of transient temperature field in the glass mold
57 s., 10 s. příl. :obr., tab., grafy +CD ROMPředmětem této diplomové práce je analýza nestacionárního teplotního pole ve sklářské formě. V práci jsou prezentovány výsledky tepelné analýzy počítané na modelech sklářských forem, které jsou v současnosti používány. K řešení tohoto problému bylo využito výpočtového softwaru ANSYS 14.5, který je založen na metodě konečných prvků. Hlavní výstupy práce jsou výsledky analýzy spočítané pro modely forem a návrhy na zlepšení parametrů výrobního procesu