Abstract
In this study, a set of experiments were carried out in a 21-story full-scale building varying stairwell ventilation state to investigate the fire behavior and smoke temperature distribution ...in the stairwell. Results demonstrate that the ventilation state of top vents has a great influence on the fire behavior and smoke temperature distribution than the bottom vents. The flame inclines to the stairwell with top vents open during the steady stage, while with top vents closed, it just tilts slightly to the side wall. The mass loss rates and temperature attenuations with top vents closed are larger than those with top vents open. In addition, the open of bottom vents can cause a reduction in the smoke temperature. These unique full-scale experiments provide crucial experimental data that help the design of safer smoke ventilation systems for stairwells in a high-rise building.
Context
. We investigate the properties of the emission region in PSR J0815+0939 as revealed by the bidrifting subpulses.
Aims.
We identify the emission properties as implied by different states of ...emission, including the charge density and the subpulse number on the carousel, in association with the different subpulse drift properties in bidrifting.
Methods.
The investigation is based on the rotating carousel, incorporating the model for obliquely rotating pulsar magnetospheres of multiple emission states. For the subpulse drift velocity given by the electric drift, the latter changes as the emission state changes, resulting in the observed different drift-bands.
Results.
Our results show that observable emission of this pulsar comes from two rotating carousels. The carousel at higher height is occupied by two different emission states. We find that the subpulse drift direction is different for emission coming either from different emission states on the same carousel or from similar emission states, but located on different carousels. We consider that establishing the subpulse number on a carousel may involve a mechanism that is not a function of the age or the obliquity angle of the pulsar. We discuss that bidrifting may be a common phenomenon, but its detection requires particular emission characteristics of the pulsar. We relate different subpulse drift modes in bidrifting with drifting subpulses of time-dependent drift rates, and speculate that they may be two manifestations of the same underlying mechanism.
Timing irregularities of PSR J1705–1906 Liu, Y. L.; Yuan, J. P.; Wang, J. B. ...
Astrophysics and space science,
05/2018, Letnik:
363, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Timing analysis of PSR J1705–1906 using data from Nanshan 25-m and Parkes 64-m radio telescopes, which span over fourteen years, shows that the pulsar exhibits significant proper motion, and rotation ...instability. We updated the astrometry parameters and the spin parameters of the pulsar. In order to minimize the effect of timing irregularities on measuring its position, we employ the Cholesky method to analyse the timing noise. We obtain the proper motion of
−
77
(
3
)
mas yr
−1
in right ascension and
−
38
(
29
)
mas yr
−1
in declination. The power spectrum of timing noise is analyzed for the first time, which gives the spectral exponent
α
=
−
5.2
for the power-law model indicating that the fluctuations in spin frequency and spin-down rate dominate the red noise. We detect two small glitches from this pulsar with fractional jump in spin frequency of
Δ
ν
/
ν
∼
2.9
×
10
−
10
around MJD 55199 and
Δ
ν
/
ν
∼
2.7
×
10
−
10
around MJD 55953. Investigations of pulse profile at different time segments suggest no significant changes in the pulse profiles around the two glitches.
The 2016 glitch in the Vela pulsar Xu, Y. H.; Yuan, J. P.; Lee, K. J. ...
Astrophysics and space science,
2019/1, Letnik:
364, Številka:
1
Journal Article
Recenzirano
We report the detection of a glitch event in the Vela pulsar, which occurred on 12 December 2016, based on the timing data obtained from observations between January 2016 and February 2018 at ...frequency centered at 2256 MHz using the Kunming 40-m radio telescope. The timing solutions for the pre- and post-glitch are presented. By fitting the glitch model to the timing data, we found that the post-glitch recovery exhibits two terms with exponential decay with the time scales of 1 d and 6 d, respectively. The glitch parameters are determined with
Δ
ν
g
/
ν
=
1.431
(
2
)
×
10
−
6
and
Δ
ν
˙
g
/
ν
˙
=
73.354
×
10
−
3
. The value of the coupling parameter is calculated to be ∼0.08, implying that the core superfluid is probably not involved in this event. For the glitches with two or more terms with exponential decay in the Vela pulsar, we show that the exponential decays usually exhibit longer time scales with higher degree of glitch recovery. The post-glitch behavior in the slow-down rate
|
ν
˙
|
is dominated by a linear decrease process. From detection of the variations in the slopes of the spin-down rates after the exponential recoveries of the 2013 and 2016 glitches, we conclude that no persistent shift was involved in the 2016 glitches.
Protein kinase C (PKC) is an attractive target in cancer therapy. It is overexpressed in a variety of cancers, and nonspecific
inhibitors of PKC have demonstrated antitumor activity. Antisense ...oligonucleotides targeted against PKC-α, which have high
specificity, can inhibit mRNA and protein expression as well as the growth of tumors in vitro and in vivo . This Phase I study sought to characterize the safety profile and to determine the maximum tolerated dose of antisense to
PKC-α when administered by continuous infusion in patients. Patients with incurable malignancies received ISIS 3521, a 20-length
phosphorothioate oligodeoxynucleotide specific for PKC-α. Treatment was delivered over a period of 21 days by continuous i.v.
infusion followed by a 7-day rest period. Doses were increased from 0.5 to 3.0 mg/kg/day. Patients continued on the study
until evidence of disease progression or unacceptable toxicity was detected. Between August 1996 and September 1997, 21 patients
were treated in five patient cohorts. The maximum tolerated dose was 2.0 mg/kg/day. The dose-limiting toxicities were thrombocytopenia
and fatigue at a dose of 3.0 mg/kg/day. Pharmacokinetic measurements showed rapid plasma clearance and dose-dependent steady-state
concentrations of ISIS 3521. Evidence of tumor response lasting up to 11 months was observed in three of four patients with
ovarian cancer. The recommended dose of ISIS 3521 for Phase II studies is 2.0 mg/kg/day when given over a period of 21 days.
Side effects are modest and consist of thrombocytopenia and fatigue. Evidence of antitumor activity provides the rationale
for Phase II studies in ovarian cancer and other malignancies.
Bourque DK, Peñaherrera MS, Yuen RKC, Van Allen MI, McFadden DE, Robinson WP. The utility of quantitative methylation assays at imprinted genes for the diagnosis of fetal and placental disorders.
An ...imbalance of imprinted gene expression within 11p15.5 is observed in Beckwith‐Wiedemann syndrome (BWS), as well as in a variety of placental abnormalities including complete hydatidiform mole (CHM), placental mesenchymal dysplasia (PMD) and triploidy. To facilitate the diagnosis of epigenetic errors and chromosomal imbalance of 11p15.5, we validated a pyrosequencing assay to measure methylation at KvDMR1 using blood samples from 13 BWS cases, 8 of which showed reduced methylation as compared to control blood. An imbalance between maternal and paternal genomes as is found in triploidy, CHM or PMD was also associated with altered KvDMR1 methylation. A reciprocal pattern of methylation was obtained in the triploid cases by assaying the proximal 11p15.5 ICR associated with H19. To distinguish chromosome 11 specific alterations from whole genome imbalance, other imprinted differentially methylated regions (DMRs) can be utilized. Thus, pyrosequencing assays for DMRs associated with SGCE, SNRPN, and MEST were also compared for their utility in diagnosing parental imbalance in placental samples. While each of these assays could successfully distinguish parental origin of triploidy, SGCE showed the clearest separation between groups. The combined use of a chromosome 11p15.5 assay (e.g. KvDMR1 or H19‐ICR) and non‐chromosome 11 assay (e.g. SGCE) provides a potentially valuable diagnostic tool in the rapid screening of methylation errors in placental disorders. These results also show the maintenance of imprinting status at these loci in the human placenta, even in the presence of abnormal pathology.
Obtaining the burning properties of nitrocellulose with different ethanol contents is necessary to reduce the possibility of nitrocellulose accidents in the process of handing, storage and usage. In ...this study, the effect of humectant content on the burning properties of NC was tested by the ISO 5660 Cone Calorimeter Test. It was noted that the amount of the ethanol content had little effect on the ignition time of nitrocellulose mixture. Both the maximum mass loss rate and the average mass loss rate of the sample decreased with an increasing ethanol content and gradually closed to fixed values. Also, it was concluded that the peak heat release rate of the sample was mainly contributed by the nitrocellulose component.
Application of a three-dimensional mathematical model for the pyrolysis of wet wood coupled with the gas phase combustion to the analysis of a wood sample ignited in a cone calorimeter is described. ...Time-dependent chemical and physical processes of wet wood model described in Part I is employed with transient gas phase flow described by Navier–Stokes equations. Predicted ignition times compared well against experimental data for cone irradiation fluxes of 20–70
kW
m
−2 with initial moisture contents of 0%, 5% and 10%. This study further demonstrates the feasibility of application of the developed wet wood model in fire-engineering.
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