1,066 research outputs found
FEC decoder design optimization for mobile satellite communications
A new telecommunications service for location determination via satellite is being proposed for the continental USA and Europe, which provides users with the capability to find the location of, and communicate from, a moving vehicle to a central hub and vice versa. This communications system is expected to operate in an extremely noisy channel in the presence of fading. In order to achieve high levels of data integrity, it is essential to employ forward error correcting (FEC) encoding and decoding techniques in such mobile satellite systems. A constraint length k = 7 FEC decoder has been implemented in a single chip for such systems. The single chip implementation of the maximum likelihood decoder helps to minimize the cost, size, and power consumption, and improves the bit error rate (BER) performance of the mobile earth terminal (MET)
Partition lies, Advaita Vedanta and Bhisham Sahni’s Tamas
This is a re-look at the (Indian) Partition event through the lens of Advaita Vedanta
Analytic formulas for frequency and size dependence of absorption and scattering efficiencies of astronomical polycyclic aromatic hydrocarbons
In a series of two recent papers, the frequency and size distribution
dependence of extinction spectra for astronomical silicate and graphite grains
was analyzed by us in the context of MRN type interstellar dust models. These
grains were taken to be homogeneous spheres following the power law
size distribution which is very much in use. The analytic formulas
were obtained for the graphite and silicate grains in wavelength range 1000\AA
- 22,500\AA and their utility was demonstrated. In this paper of the series, we
present analytic formulas for the scattering and absorption spectrum of another
important constituent of interstellar dust models, namely, the polycyclic
aromatic hydrocarbons (PAHs). Relative contribution of the PAHs to extinction
{\it vis a vis} carbonaceous classical grains has been examined.Comment: 19 pages, 4 figures, to appear in JQSRT 201
Large diamagnetic persistent currents
In multichannel rings, evanescent modes will always co-exist with propagating
modes. The evanescent modes can carry a very large diamagnetic persistent
current that can oscillate with energy and are very sensitive to impurity
scattering. This provides a natural explanation for the large diamagnetic
persistent currents observed in experiments.Comment: 5 figure
Evaluation of saturated hydraulic conductivity from soil properties in an Inceptisol using different land cover and depths
hree soil profiles from Regional Research Station of Bidhan Chandra Krishi Viswavidyalaya, Gayeshpur situated in New Alluvial zone of Nadia district, West Bengal were studied to assess the predictability of the hydraulic conductivity of the soil as influenced by different physical and chemical and properties of cultivated and forest land. The various statistical procedures were employed on the measured laboratory based data for comprehensive agree-ment of dependent hydraulic conductivity of soils as a model function of independent soil variables that is likely to be useful for different land cover systems. Soils are neutral in reaction, silty clay to silty clay loam in nature. Forest soil contained greater organic carbon (OC) (5.9 ± 0.16 g kg-1) compared to cultivated soil (4.4 ± 0.34 g kg-1). Jhau plan-tation recorded the highest value (6.8 g kg-1) of OC due to soil texture and cation exchange capacity (CEC). Soil hydraulic conductivity was greater in soil for cabbage and Sagun tree among the cultivated and forest soil studied with values 2.80 and 1.10 cmh -1. Correlation study showed a positive and negative relation with hydraulic conductiv-ity for sand (r= 0.68; P > 0.05) and clay (r= - 0.71; P > 0.05) respectively. Further, principal component analysis con-cluded that addition of bulk density with clay and sand can predict the hydraulic conductivity for different land uses
Activating ZnO nanorods photoanodes in visible light by CdS surface sensitiser
Thin films of c-axis aligned uniform ZnO nanorods (NRs) were fabricated on to fluorine-doped tin oxide-coated soda lime glass substrate by a two-step chemical route. Thereafter ZnO NRs/CdS core shell structures were successfully synthesised by depositing CdS layer on top of vertically aligned ZnO NRs using less hazardous nanocrystal layer deposition technique. The presence of CdS in ZnO NRs/CdS core shell structures was confirmed by energy dispersive X-ray analysis. Examination of structure and morphology of the fabricated films by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) revealed that both films have one-dimensional hexagonal wurtzite structure. Optical properties evaluated from ultraviolet-visible and photoluminescence spectra demonstrated better photo response of ZnO NRs/CdS core shell structure with respect to bare ZnO NR structure. Optical to chemical conversion efficiency of ZnO NRs/CdS photoanode was found to be similar to 1.75 times higher than bare ZnO NRs photoanode in photo electrochemical water splitting under visible light
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