Assam Don Bosco University Journals
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Design of Soil Moisture Sensor for Validation of Passive Microwave Remote Sensed Soil Moisture Data
Get PDFSoil Moisture is an important parameter that is of immense importance in the field of civil engineering, agriculture and ecology. Development of weather patterns and intake of nutrient by plants depend on soil moisture. In this paper, the design of sensor is described that uses the electrical resistance attribute of soil moisture. The soil moisture product of Advanced Microwave Scanning Radiometer-2 on board GCOM satellite of Japan Aerospace Exploration Agency (JAXA) is then compared with the soil moisture obtained from the designed sensor. Analysis shows the variability of the soil moisture values measured by both the satellite as well as the actual soil moisture measured by gravimetric method for the samples collected from different locations. The designed sensor shows similar variations in its output. Hence, the designed sensor can be used for checking the variations happening in soil moisture values instantaneously and can be used to validate the soil moisture product of remote sensing satellites for different location
The Influence of Social Referents on Alcohol Use Behaviour of College Students
Get PDFAlcohol continues to be the substance of choice for many youth of today, leading to serious physical, psychological and social consequences. Drinking habit has a long-range consequence and that includes the influence it has got on the drinking habit of the continuing generation. This study establishes the level of association between drinking behaviour and the attitude of social referents to drinking on the drinking behaviour of the adolescents and their attitude to drinking. A study on the 400 college going graduate students, with a mean age of 20.01 and standard deviation of 1.672, of West Siang district of Arunachal Pradesh largely establishes an association between adolescents and their social referents. Parental habits and attitudes are transferred to the children in many situations. The Galos, who have been traditionally and historically grouped together with the other Abor groups of tribes, are a major tribe of Arunachal Pradesh. Eighty nine percent of the respondents belonged to this tribal population with 53.8 percent male and 46.2 percent female respondents
ACTIVITY OF DABCO: CATALYTIC SCOPE IN ORGANIC SYNTHESIS
Get PDF1,4-DiAzaBiCyclo[2.2.2.]octane (DABCO) is a good neucleophile and base in number of organic reactions and gaining particular importance as catalyst in synthetic organic chemistry. Catalytic applications of DABCO in various reactions such as cycloaddition reaction, coupling reaction, Baylis-Hillman reaction, Henry reaction, ring opening reaction etc. are noteworthy in synthesis of novel organic scaffold. In this article it is tried to overview the recent development of DABCO catalysed reaction as well as its use in heterocyclic synthesis
A REVIEW OF THE ELEMENTS OF NUCLEAR MAGNETIC RESONANCE INSTRUMENTATION
Get PDFThe early efforts to detect nuclear magnetic resonance (NMR) when reviewed, carries a valuable message on how to go about making discoveries of phenomena on the basis of what is known already. Particularly the instrumentation is an effort which has an outlook on enterprises that provide various laboratory equipments and assembling these units in a way that brings out precisely what is being looked for is a creative preoccupation in scientific research. The kind of home-built spectrometers which have been used by every researcher for the achievements in the NMR spectroscopic technique is an example of the material manipulation to improve stage by stage thoughtfully knowing what went on before. Thus the review would have educative value while revealing the lessons on scientific matter studied. NMR of the current days is aplenty with commercial spectrometers which have unimaginable features built in and produce high quality spectra automatically without the user having to know much about the settings. Essentially black-box approach to the use of the spectrometers makes possible strides in leaps and jumps in a wide variety of disciplines of study. On the other hand the early efforts have been more educative on the equipments and instrumentation aspects. The researchers themselves had a hand on laboratory exercise to make the equipment for what they have to research on. In this contrasting situation a review of the early days NMR instrumentation is provided in this article for the benefit of student community to find an occupation while innovating their learning methods. Descriptions in this article are oriented towards school and college standards so as to inspire the readers to look for more on instrumental methods and grasp the recent advances quickly and confidently in these days of conveniently automated and much simplified ‘black-box’ approach to use of instruments. An important point to mention is that the circuit diagrams given in this articles are the author’s original version of block diagrams or schemes similar to concept diagrams (pedagogically speaking) to introduce newly certain topics. Hence the students should not expect to plug in working circuits to see the functions. Note carefully that no specific component value is given nor any model numbers to commercially available components – even the circuit elements are not copied ones but drawn by the author with MS WORD drawing tools
SUPERSOFT X-RAY SOURCES: A REVIEW STUDY
Get PDFFollowing their discovery by the Einstein satellite, supersoft X-ray sources (SSXS) are presently considered to be an important new class of X-ray binaries. These sources are characterised by X-ray luminosities erg s and spectral peaks occuring in 15--80 eV. More than 100 SSXS have been discovered so far in the Milky Way, the Magellanic Clouds and 20 other nearby galaxies. The currenly accepted model for a supersoft source is that of an accreting white dwarf with steady nuclear burning. Detailed calculations have revealed a narrow range of mass accretion rates which can sustain the SSXS. Such a window of mass accretion leads to the identification of possible companions to the white dwarf in an SSXS, which further leads to a classification scheme. The CBSS subclass of SSXS assumes special significance because it has been shown that they are strong candidates as progenitors for supernovae of Type Ia. The study of high-resolution X-ray spectra of SSXS reveals detailed rich spectral features due to high gravity white dwarfs. Fitting of such spectra require multiple model components.Following their discovery by the Einstein satellite, supersoft X-ray sources (SSXS) are presently considered to be an important new class of X-ray binaries, with characteristic X-ray luminosities erg s and spectral peaks occuring in 15--80 eV. More than 100 SSXS have been discovered so far in the Milky Way, the Magellanic Clouds and 20 other nearby galaxies. Interstellar extinction of soft X-rays plays a major role in determining the number of SSXS being observed in a particular galaxy. Originally, because of the similarity in the SSXS spectra with those of LMXBs, near-Eddington accretion onto neutron stars was thought to be the model for SSXS. However, because of later detailed computations following their luminosities and temperatures, it has been demonstrated that accreting white dwarf with steady nuclear burning is a more suitable model for SSXS, as is currently considered. The sustainability of an SSXS has been shown to depend on three possible regimes of nuclear burning, demonstrating the existence of a narrow range of mass accretion rate between wherein the nuclear fuel burns steadily. Other accretion rates are shown to explain transient SSXS and those with an accompanying stellar wind. Such a window of mass accretion leads to the identification of possible companions to the white dwarf in an SSXS, further leading to a classification scheme, with close binary supersoft sources (CBSS), symbiotic systems (SS) and cataclysmic variables (CV) being the dominant binary systems manifesting as SSXS. The CBSS subclass of SSXS assumes special significance because it has been shown that they are strong candidates as progenitors for supernovae of Type Ia because they provide the mass accretion rates appropriate for a sub-Chandrasekhar double detonation, which is an off-centre model for type Ia supernovae at sub-Chandrasekhar masses. To obtain an estimate of spectral parameters of the SSXS, the fitting of its observed spectrum to a model spectrum is crucial. The investigation of high-resolution X-ray spectra of SSXS reveals detailed rich spectral features due to high gravity white dwarfs as also P Cygni profiles which are characteristic of the presence of stellar winds. Fitting of such spectra require multiple model components. In particular, for a particular SSXS named RX J0925.7-4758, we have been able to obtain, at an initial stage, an unprecedented good fit using a multi-component model and further study is presently under way
EFFECT OF MIXED COUNTERIONS ON THE AGGREGATION BEHAVIOR OF CETYLPYRIDINIUM CHLORIDE
Get PDFCritical micelle concentrations (cmc) of cetylpyridinium chloride (CPC) in aqueous sodium bromide and tetrabutylammonium bromide (TBAB) solutions were determined at 30 °C from surface tension and conductance methods. Bromide decreases cmc of CPC more than chloride. A modified form of Corrin-Harkins equation has been used to describe the variation of cmc with added electrolyte concentration in the presence of mixed counter ions. From the slope of this equation the lower limit to the value of total counter ion binding constant (β) can be known and binding constants of the individual counter ions (β1 and β2) can be determined provided β is known. It is demonstrated that the mixed-electrolyte-model (MEM) of Shanks and Franses (J. Phys. Chem. 1992, 96, 1794) can be applied to analyze the conductance data of surfactant solution containing mixed counter ions. The value of β obtained from the MEM was then used to determine β1 and β2. By this treatment we could show that (i) bromide preferentially binds to CPC micelle by replacing chloride counterion, (ii) bromide binding is more than chloride and (iii) aggregation number of CPC is higher in the presence of bromide. These observations are in accordance with the reported results of SANS and counter ion trapping studies
Design of Electronic Load Controllers of Induction Generators used in Micro Hydro Power Schemes
Get PDFThis paper describes the use of Electronic Load Controller on micro hydro power scheme in which no separate penstock is required to control the speed of the flow of water. The Electronic Load Controllers (ELC) is an electronic device in which the output of the generator can be maintained constant instead of changing or fluctuating user loads. The ELC maintains a constant generator output by introducing a separate load called ballast load which absorbs the load required by the consumer. This paper also explains and demonstrate a simulation model of an ELC
Identification & Mapping of Mustard Cultivation Sites Using a Multi Criteria Evaluation Approach (MCEA) for Kamrup District of Assam, India
Get PDFLand suitability analysis is a pre requisite to achieve optimum utilization of available land resources for sustainable agricultural management. One of the most important agriculture related issues in the state of Assam is to improve the agricultural output with an efficient use of available land resources. Agriculture is the prime economic activity for most of the people of Assam but the overall production figures for different agricultural crops are still stands at a notably lower level compared to the national average. The aim of the present study is to assess the physical land suitability level for Mustard crop using a Multi-Criteria Evaluation (MCE) method with the help of GIS Remote sensing tool. The existing pattern of physiographic, meteorological and soil based components were thoroughly considered for the identification mapping of mustard cultivation sites of Kamrup district with the help of geospatial tool. Present Landuse/Land cover scenario of the study area highlights that although a substantial portion out of the total geographical area falls under agricultural landuse category but it has distinctly been noticed that a major shrunk of future suitable area are till unutilized. The landuse/land cover statistics of the area shows that the Mustard cultivation is confined to only 178.82 sq.km area which shows a huge possibility of further increase in Mustard cultivation sites in coming years. “Overlay analysis†method in GIS based environment was applied to prepare an “Index model†for multi criteria analysis of different natural and soil parameters. Finally, the results show that mustard cultivation sites are mainly concentrated only in the plain areas and in the river adjacent fertile tracts adjacent to river Brahmaputra and its tributaries
NDVI and NDWI based Change Detection Analysis of Bordoibam Beelmukh Wetlandscape, Assam using IRS LISS III data
Get PDFThis paper analyses per pixel change detection of Bordoibam Beelmukh wetlandscape located in Dhemaji district of Assam, India, which covers around 23 sq. km of geographical area. Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) are the two remote sensing indices applied for change detection analysis in the study area. IRS LISS III satellite imageries with 23.5 meter spatial resolution have been used to conduct the analysis. These satellite imageries have been collected from NRSC Bhuvan portal with 5 years temporal interval (2008 to 2013). Image differencing technique has been applied to detect per pixel change using NDVI and NDWI difference image results of the wetlandscape. The study has observed per pixel change detection in five distinct categories for both NDVI and NDWI results of the study area. These are increased more than 5 percent, decreased more than 5 percent, some increase, some decrease and unchanged. In this regard, the study reveals that there is maximum change (79% to total change) in increased more than 5 percent category for NDVI, whereas for NDWI maximum change (96% to total change) is observed under decreased more than 5 percent category of the study area. It has been also observed that there are significant changes of both NDVI and NDWI values from 2008 to 2013 in the study area which in turn indicate changes of vegetation and water cover areas of the same