2,578 research outputs found
Observational constraints on the nature of very short gamma-ray bursts
We discuss a very peculiar subgroup of gamma-ray bursts among the BATSE
sources. These bursts are very short (0.1 s), hard, and came
predominantly from a restricted direction of the sky (close to the Galactic
anti-center). We analyze their arrival times and possible correlations, as well
as the profiles of individual bursts. We find no peculiarities in the arrival
times of Very Short Bursts (VSBs) despite their highly non-uniform spatial
distribution. There is no dependence in the burst shapes on location. Bursts
coming both from the burst-enhancement Galactic Anticenter region and from all
other directions show considerable dispersion in their rise and fall times.
Significant fraction of VSBs have multiple peaks despite their extremely short
duration. Burst time properties are most likely to be consistent with two
origin mechanisms: either with binary NS-NS mergers with low total masses
passing through a phase of hypermassive neutron star, or with evaporation of
the primordial black holes in the scenario of no photosphere formation.Comment: 25 pages, 14 figures; accepted to New Astronom
Ecological Life Cycle Assessment Modified Novolaks Waste Used in Industrial Wastewater Treatment
Ecological Life Cycle Assessment (LCA) applied in the assessment of the impact
of products on the environment is a technique that allows for the evaluation of the
environmental impact of polymeric flocculants used in industrial wastewater treatment.
The possibility of conducting a full life cycle and thus manufacturing process analysis
allows for reliable and accurate identification of the sources of environmental hazards
and the impact of new products on the environment. Newly synthesized waste-based
polymers are water soluble and possess the properties of flocculants, while reducing the
parameters in industrial wastewater. In the paper, there are presented the results of the
analysis conducted using LCA technique for the assessment of the impact of modified
waste phenol formaldehyde resin (Novolak) on the environment. LCA technique was
used to assess the impact of the new flocculant applied in the process of metallurgical
wastewater treatment taking into account the environmental impact of the fl occulant
manufacturing process
Building Information Modeling as Tool for Enhancing Disaster Resilience of the Construction Industry
As frequencies of the disasters are increasing, new technologies can be used to enhance
disaster resilience performance of the construction industry. This paper investigates
the usage of BIM (Building Information Modeling) in enhancing disaster resilience of
the construction industry and in the establishment of the resilient built environment.
In-depth literature review findings reveal BIM’s contribution to the disaster resilience in the
pre-disaster and post-disaster phases especially through influencing the performance of
the supply chain, construction process, and rescue operations. This paper emphasises
the need for BIM’s integration to the education and training curriculums of the built
environment professionals. Policy makers, construction professionals, professional
bodies, academics can benefit from this research
Transmission Phase of a Quantum Dot with Kondo Correlation Near the Unitary Limit
The complex transmission amplitude -- both magnitude and phase -- of a
quantum dot (QD) with Kondo correlation was measured near the unitary limit.
Contrary to previous phase measurements, performed far from this limit [Ji et
al., Science 290, 779 (2000)], the transmission phase was observed to evolve
linearly over a range of about 1.5 pi when the Fermi energy was scanned through
a Kondo pair -- a pair of spin degenerate energy levels. Moreover, the phase in
Coulomb blockade (CB) peak, adjancent to the Kondo pair, retained a memory of
the Kondo correlation and did not exhibit the familiar behavior in the CB
regime. These results do not agree with theoretical predictions, suggesting
that a full explanation may go beyond the framework of the Anderson model.Comment: 4 pages, 4 figure
Current Approaches of Occupational and Safety Health Management in Work Environments Containing Nanoparticles
The development of nanotechnology is particularly in recent years very dynamic and is
applied in many not only technical branches. This is not possible to say about monitoring
of possible health and environmental undesirable influence. The first area of possible risk
assessment is work environment because there is a lot of possible ways to exposition.
The aim of the paper is to analyze current situation in the field of occupational safety
and health management in the workspace with occurrence of nanoparticles not only
like the engineered nanomaterials. Because there is a lot of influence which could have
the negative impact on the employee's healt
Hybrid methods based on empirical mode decomposition for non-invasive fetal heart rate monitoring
This study focuses on fetal electrocardiogram (fECG) processing using hybrid methods that combine two or more individual methods. Combinations of independent component analysis (ICA), wavelet transform (WT), recursive least squares (RLS), and empirical mode decomposition (EMD) were used to create the individual hybrid methods. Following four hybrid methods were compared and evaluated in this study: ICA-EMD, ICA-EMD-WT, EMD-WT, and ICA-RLS-EMD. The methods were tested on two databases, the ADFECGDB database and the PhysioNet Challenge 2013 database. Extraction evaluation is based on fetal heart rate (fHR) determination. Statistical evaluation is based on determination of correct detection (ACC), sensitivity (Se), positive predictive value (PPV), and harmonic mean between Se and PPV (F1). In this study, the best results were achieved by means of the ICA-RLS-EMD hybrid method, which achieved accuracy(ACC) > 80% at 9 out of 12 recordings when tested on the ADFECGDB database, reaching an average value of ACC > 84%, Se > 87%, PPV > 92%, and F1 > 90%. When tested on the Physionet Challenge 2013 database, ACC > 80% was achieved at 12 out of 25 recordings with an average value of ACC > 64%, Se > 69%, PPV > 79%, and F1 > 72%.Web of Science8512185120
Assurance of quality and the accessibility of public spaces under current legislation
This paper focuses on the issue of accessibility
and the quality of public space, particularly its
barrier - free use and relation to current Czech legislation.
The legislative framework should help reshape
theoretical knowledge and contemplations of this issue
into live practice, which is met with varying success.
Important factors in this field include the continuity of
the legislative environment and specifics for the given
region (primarily in the border regions where there is
a collision of the "domestic" and "foreign" legal environments)
Grid Power Quality Enhancement Using Fuzzy Control-Based Shunt Active Filtering
Active filtering has proved efficient for the mitigation of harmonics in distribution grids. This paper deals with the design of fuzzy control strategies for a three-phase shunt active filter to enhance the power quality via the regulation of the DC bus voltage of the distribution network. The proposed control scheme is based on Interval Type 2 Fuzzy Logic controller. A simulation study is performed under Simulink/Matlab to evaluate the performance and robustness of the proposed control schemePeer reviewedFinal Accepted Versio
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