11,124 research outputs found
Geomagnetic storm effects on GPS based navigation
The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere) comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS) that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena. <br><br> Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC) measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(&gt;10 dB) L-band scintillation events, adversely affecting the GPS based navigation
Factors Influencing the Usage of ICT in Secondary Schools: A Case Study in Telangana State of India
Results are reported from a study in which teachers’ views on usage and impact of information and communication technology in secondary schools, were compared between private and government schools and between the state board (SSC) syllabus and CBSE board syllabus. The main purpose of the study was to answer the following questions: Firstly, How socio economic parameters can impact the ICT usage, Secondly, What differential role does ownership (Public/Private) of the management has an impact on the usage of ICT and Thirdly, How the board of education can have an impact on the usage of ICT in secondary schools? The key finding the study are as follows First, Gender, age group has no impact on ICT usage, Secondly, the ownership of management i.e Government schools Vs private schools has no impact on the usage of ICT in secondary schools, Thirdly, it’s been observed that there is a significant impact of board of education , i.e State board Vs CBSE board on the usage of ICT in secondary schools Keywords: Gender, age, income, StateSecondary Certificate (SSC), Central Boardfor Secondary Education(CBSE), ICT, government, privat
Novel phytosynthesis of nanoparticles using Indigeneous Australian Plants
Nanoparticles are considered to be the building blocks of nanotechnology. Biosynthesis of nanoparticles using plant material is an exciting and relatively new developing research area in nanobiotechnology. In the present study, Eucalyptus leaves were collected from Olive pink botanical garden, Alice Springs, Australia and were used to synthesize silver nanoparticles. Cubical structured and well monodispersed silver nanoparticles were formed with an average size of 50nm. The formed silver nanoparticles are found to have promising applications in medicine as good antimicrobial agents. To the best of our knowledge this is the first report on exploiting indigeneous Australian plant sources for the synthesis of metallic nanoparticles
Elasticity-mediated self-organization and colloidal interactions of solid spheres with tangential anchoring in a nematic liquid crystal
Using laser tweezers and fluorescence confocal polarizing microscopy, we
study colloidal interactions of solid microspheres in the nematic bulk caused
by elastic distortions around the particles with strong tangential surface
anchoring. The particles aggregate into chains directed at about 30 degrees to
the far field director and, at higher concentrations, form complex kinetically
trapped structures. We characterize the distance and angular dependencies of
the colloidal interaction forces.Comment: 6 pages, 5 figure
Visualisation of an entangled channel spin-1 system
Co-variance matrix formalism gives powerful entanglement criteria for
continuous as well as finite dimensional systems. We use this formalism to
study a mixed channel spin-1 system which is well known in nuclear reactions. A
spin-j state can be visualized as being made up of 2j spinors which are
represented by a constellation of 2j points on a Bloch sphere using Majorana
construction. We extend this formalism to visualize an entangled mixed spin-1
system.Comment: 4 pages,4 figure
Controllability and Observability of Kronecker Product Sylvester System on Time Scales
The main objective in this paper is to present the necessary and sufficient conditions for complete controllability, complete observability associated with kronecker product Sylvester system on time scales.2000 Mathematics Subject Classification: 93B05,93B07,49K15
Experimental Study and Optimization of Machining Parameters in Turning of AISI 1040 Steel with Micro-grooved WC Cutting Tools
In dry turning, control over chip formation and the need for the automated machining lead to an advancement in cutting tools. Such concern towards chip breakability is necessary in reducing tool wear, tool tip temperatures and surface roughness of workpiece material. The present study proposes a new development in the traditionally available cutting tools, which acts like a chip breaker. A series of micro-grooves are machined on the rake face of Tungsten carbide (WC) cutting tools using sinker Electric Discharge Machine (EDM). These micro-grooved tools are used to dissolve long continuous chips and heat from the cutting zone in the dry machining of AISI 1040 steel. The results of micro-grooved cutting tools have shown improvement in reducing the tool tip temperatures and surface roughness compared to the conventional cutting tools. The consolidated chip flow phenomenon of plain WC tools is used to decide the location of micro-grooves on the tool rake face. A Taguchi orthogonal array is used to design an experimental layout with minimum number of repetitions in the experiments. Signal-to-noise ratios and ANOVA is used to understand and identify the significant factors & their level among the input variables on responses.From the results, it is identified that the cutting speed is the most influencing parameter for tool tip temperature at level 1 (i.e. 112 m/min) and surface roughness at level 5 (i.e. 720 m/min)
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