32,570 research outputs found
Laser ignition of an optically sensitised secondary explosive by a diode laser
As a green technology, laser ignition of a relatively insensitive secondary
explosive has been experimentally investigated. The explosive, hexanitrostilbene
(HNS), was doped with one of two optical sensitizers, carbon black or a laser
absorbing dye, and a continuous-wave (CW) infrared diode laser was used as the
igniting source. The ignition sensitivities of HNS with each of the two optical
sensitizers were analysed and compared in terms of: optical power threshold for
ignition, ignition delay and full burn delay at various laser powers. The results
have shown that both the chemical dye and carbon black optically sensitize
the explosive with similar efficiencies. In contrast to the carbon black, the dye
provides wavelength specificity and selectivity in the laser ignition process and its
solubility in some specific solvents improves the coating of the explosive material.
It was therefore concluded that the laser absorbing dye is a better candidate for
optical sensitization in laser ignition than the commonly used carbon black. The
combination of laser ignition sensitivity with wavelength selectivity potentially
offers higher reliability and safety at a low optical power for future ignitors of
secondary explosives
The effect of surface reflection and clouds on the estimation of total ozone from satellite measurements
The total amount of ozone in a vertical column is being measured by Nimbus 4 and 7 observations of the intensity of ultraviolet sunlight scattered from the earth. The algorithm for deriving the amount of ozone from the observations uses the assumption that the surface reflects the light isotropically and the albedo is independent of wavelength. The effects of anisotropic surfaces and clouds on the estimate of total ozone are computed for models of the earth-atmosphere system
Mapping of Landslide Hazard Distribution in Alo Watershed Gorontalo Regency
Landslide occurrence can be influenced by physical factors and human activities. Thus, research related to the provision of information about landslide distribution in Alo watershed is needed as a basis in enhancing community preparedness in dealing with disasters. The method used in this study is the scoring method based on the Minister of Public Works Regulation No.22 / PRT / M / 2017 which is processed through a geographical information system through the overlay of all physical parameters. The result shows that the Alo watershed area is divided into three vulnerability categories. "Low" category covers 7171.8 ha, "medium" category covers 12008.7 ha, and "high" category covers 5039.5 ha out of 24.221 ha the total area of Alo watershed. Information provided in this research is expected to be able to help the local government in making policies in managing the Alo watershed area and enhancing the understanding of the local community in Alo watershed in dealing with disasters
AMCTD: Adaptive Mobility of Courier nodes in Threshold-optimized DBR Protocol for Underwater Wireless Sensor Networks
In dense underwater sensor networks (UWSN), the major confronts are high
error probability, incessant variation in topology of sensor nodes, and much
energy consumption for data transmission. However, there are some remarkable
applications of UWSN such as management of seabed and oil reservoirs,
exploration of deep sea situation and prevention of aqueous disasters. In order
to accomplish these applications, ignorance of the limitations of acoustic
communications such as high delay and low bandwidth is not feasible. In this
paper, we propose Adaptive mobility of Courier nodes in Threshold-optimized
Depth-based routing (AMCTD), exploring the proficient amendments in depth
threshold and implementing the optimal weight function to achieve longer
network lifetime. We segregate our scheme in 3 major phases of weight updating,
depth threshold variation and adaptive mobility of courier nodes. During data
forwarding, we provide the framework for alterations in threshold to cope with
the sparse condition of network. We ultimately perform detailed simulations to
scrutinize the performance of our proposed scheme and its comparison with other
two notable routing protocols in term of network lifetime and other essential
parameters. The simulations results verify that our scheme performs better than
the other techniques and near to optimal in the field of UWSN.Comment: 8th International Conference on Broadband and Wireless Computing,
Communication and Applications (BWCCA'13), Compiegne, Franc
Office quality classification theoretical and empirical issues
Office quality classification literature recognises identification of office classes through division of office market rent distribution into intervals but failed to provide sound theoretical framework and comprehensive empirical approach to this method. This paper theorised that as office rental levels are a function of office quality; high quality office classes should have their mean rents greater than average market rent and mean rents of low quality classes. Also that heterogeneous nature of property coupled with lack of perfect information to market participants could result into differential evaluation of rent and quality of the same property by different market participants. The behaviour of participants normally reflects in distribution of market rent by depicting natural breaks in the distribution that could be captured by univariate data exploration. Frequency and histograms of rent distributions that were assumed to depict the behaviour of market participants were used to divide rent distribution to intervals to identify office quality classes. The results of this classification were validated by discriminant analysis. 67% and 59% accuracies were achieved for estimation and holdout subsamples respectively. This paper extended theoretical and empirical approaches in office quality classification. The proposed empirical approach could be used in future classification research
Neutrino Factories: Physics Potential
The physics potential of low-performance and high-performance neutrino
factories is briefly reviewed..Comment: Talk presented at NUFACT02, London, 1-6 July, 2002. 8 pages, 5
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Breit-Wigner-Fano lineshapes in Raman spectra of graphene
Excitation of electron-hole pairs in the vicinity of the Dirac cone by the
Coulomb interaction gives rise to an asymmetric Breit-Wigner-Fano lineshape in
the phonon Raman spectra in graphene. This asymmetric lineshape appears due to
the interference effect between the phonon spectra and the electron-hole pair
excitation spectra. The calculated Breit-Wigner-Fano asymmetric factor 1/qBWF
as a function of the Fermi energy shows a V-shaped curve with a minimum value
at the charge neutrality point and gives good agreement with the experimental
result.Comment: 15 pages, 4 figure
Pengaruh Math Phobia, Self-efficacy, Adversity Quotient Dan Motivasi Berprestasi Terhadap Prestasi Belajar Matematika Siswa SMP
This research aimed to describe direct and indirect influences of mathematics phobia, self-efficacy, Adversity Quotient, and achievement motivation on student achievement of class VII in Gowa district. This research was an ex post facto research. The subjects were 217 junior high school students of class VII derived from eight schools in eight different districts. The data obtained were analyzed by using the descriptive analysis and path analysis with statistical data processing program SPSS and AMOS. Moreover, Sobel test was used to examine the hypothesis of intervening variables. The result showed math phobia, self-efficacy, Adversity Quotient and achievement motivation has a direct and indirect influence on students mathematics learning achievement
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