996 resultados para Crue maximale probable (PMF)
Resumo:
The study documents the long-term trends in financial intermediation by the principal player in Kerala’s credit system i.e., banking. The process of financial intermediation by the banking system, involving mobilization of deposits from savers and disbursal of credit to investors, is considered to be crucial in the process of economic development. The objective of the study is to explore the interrelationship between financial intermediation and economic growth in Kerala. In order to pursue this objective, the study examine, the trends in intermediation by the banking system in Kerala over a long period, the trend and pattern of bank deposits and credit in the State and Kerala’s economic growth, the trend in the growth and performance of financial intermediaries like the All India Financial Institutions, the links between banking and economic variables, and the difference in the growth trends of banking and economic variables between Kerala and India and the probable reasons for the difference
Resumo:
In this regard Schiff base complexes have attracted wide attention. Furthermore, such complexes are found to play important role in analytical chemistry, organic synthesis, metallurgy, refining of metals, electroplating and photography. Many Schiff base complexes are reported in literature. Their properties depend on the nature of the metal ion as well as on the nature of the ligand. By altering the ligands it is possible to obtain desired electronic environment around the metal ion. Thus there is a continuing interest in the synthesis of simple and zeolite encapsulated Schiff base complexes of metal ions. Zeolites have a number of striking structural similarities to the protein portion of natural enzymes. Zeolite based catalysts are known for their remarkable ability of mimicking the chemistry of biological systems. In view of the importance of catalysts in all the areas of modern chemical industries, an effort has been made to synthesize some simple Schiff base complexes, heterogenize them by encapsulating within the supercages of zeoliteY cavities and to study their applications. The thesis deals with studies on the synthesis and characterization of some simple and zeoliteY encapsulated Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes and on the catalytic activity of these complexes on some oxidation reactions. Simple complexes were prepared from the Schiff base ligands SBT derived from 2-aminobenzothiazole and salicylaldehyde and the ligand VBT derived from 2-aminobenzothiazole and vanillin (4-hydroxy-3- methoxybenzaldehyde). ZeoliteY encapsulated Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes of Schiff base ligands SBT and VBT and also of 2-aminobenzothiazole were synthesized. All the prepared complexes were characterized using the physico-chemical techniques such as chemical analysis (employing AAS and CHN analyses), magnetic moment studies, conductance measurements and electronic and FTIR spectra. EPR spectra of the Cu(II) complexes were also carried out to know the probable structures and nature of Cu(II) complexes. Thermogravimetric analyses were carried out to obtain the information regarding the thermal stability of various complexes. The successful encapsulations of the complexes within the cavities of zeoliteY were ascertained by XRD, surface area and pore volume analysis. Assignments of geometries of simple and zeoliteY encapsulated complexes are given in all the cases. Both simple and zeoliteY encapsulated complexes were screened for catalytic activity towards oxidation reactions such as decomposition of hydrogen peroxide, oxidation of benzaldehyde, benzyl alcohol, 1-propanol, 2-propanol and cyclohexanol.
Resumo:
Two novel polystyrene-supported Schiff bases, PSOPD and PSHQAD, were synthesized. A polymerbound aldehyde was condensed with o-phenylenediamine to prepare the Schiff base PSOPD, and a polymer-bound amine was condensed with 3-hydroxyquinoxaline-2-carboxaldehyde to prepare the Schiff base PSHQAD. This article addresses the study of cobalt (II), nickel (II), and copper (II) complexes of these polymer-bound Schiff bases. All the complexes were characterized, and the probable geometry was suggested using elemental analysis, diffuse reflectance ultraviolet, Fourier transform infrared spectroscopy, thermal studies, surface area studies, and magnetic measurements.
Resumo:
The main objective of the present investigation was to study the biochemical genetic variability within the species and genetic structure of its regional populations from west coast. Realising the recent report of occurrence of oil sardine fishery in east coast of India, population samples from Mandapam and Madras were also included in the present investigation. The original data gathered on the population genetics of the species have helped to interpret and evaluate the results objectively. The important conclusions drawn from a detailed discussions on the subject would throw some light on the probable process of problematic fluctuations in the abundance of oil sardine fishery of India. The academic and applied values of present discoveries need not be emphasised. The data used for the doctoral thesis were generated during the ICAR ad-hoc project on the "Population genetic studies on oil sardine, sardinella longiceps to identity distinct genetic stocks", carried out at CMFRI, Cochin during the years, 1988-1991
Resumo:
Thermal lens signals in solutions of rhodamine B laser dye in methanol are measured using the dual beam pump-probe technique. The nature of variations of signal strength with concentration is found to be different for 514 and 488 nm Ar + laser excitations. However, both the pump wavelengths produce an oscillatory type variation of thermal lens signal amplitude with the concentration of the dye solution. Probable reasons for this peculiar behaviour (which is absent in the case of fluorescent intensity) are mentioned.
Resumo:
Absorption spectra of formaldehyde molecule in the gas phase have been recorded using photoacoustic (PA) technique with pulsed dye laser at various power levels. The spectral profiles at higher power levels are found to be different from that obtained at lower laser powers. Two photon absorption (TPA) is found to be responsible for the photoacoustic signal at higher laser power while the absorption at lower laser power level is attributed to one photon absorption (OPA) process. Probable assignments for the different transitions are given in this paper.
Resumo:
The marine microorganisms are yet to be exploited as a source of natural pigments for probable utilization in various industries. Hence, in this study focus was made only on pigment producing marine bacteria for pigment production and evaluation of the same for some application besides development of an ideal bioprocess for subsequent indigenous production of the pigment using the same organism towards ultimate industrial application.
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Plasma polymerization is found to be an excellent technique for the preparation of good quality, pinhole-free, polymer thin films from different monomer precursors. The present work describes the preparation and characterization of polypyrrole (PPy) thin films by ac plasma polymerization technique in their pristine and in situ iodine doped forms. The electrical conductivity studies of the aluminiumpolymeraluminium (AlpolymerAl) structures have been carried out and a space charge limited conduction (SCLC) mechanism is identified as the most probable mechanism of carrier transport in these polymer films. The electrical conductivity shows an enhanced value in the iodine doped sample. The reduction of optical band gap by iodine doping is correlated with the observed conductivity results.
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Studies reveal the presence of enzymes and different proteins in the venom of S.argus. The present study detected the presence of phosphodiesterase in S. argus venom. S. argus venom has displayed the presence of micromolar concentration of acetylcholine. Phospholipase activity in S. argus venom shows values below the detection threshold indicating that the venom does not possess this enzyme. The proteolylic activity of S. argus venom on casein and gelatin were assayed due to the probable involvement of proteases in causing the instability of biological activities of the fish venom. Caseinase and gelatinase enzymes were detected in S. argus venom. Though exact relationships of these enzymes and proteins in envenomation are not traced, the involvement of enzymes in envenomation cannot be ruled out. Further studies are required to find the mechanism of action of these enzymes and proteins present in S. argus venom. The present study opens new dimensions for isolation of the lethal compound present in S. argus venom. The preliminary study carried out here shows the presence of a lethal factor between 6.5 KDa - 68 KDa. Studies conclude that fish venom possesses many bioactive substances, especially peptides, proteases and enzymes that bind with high affinity to physiological targets and can be trapped for therapeutic purposes in the near future. Even though this study reveals the conundrums of S. argus venom, it opens new vistas of research on the venom components and the application and design of the venom as a drug.
Resumo:
Pollutants that once enter into the earth’s atmosphere become part of the atmosphere and hence their dispersion, dilution, direction of transportation etc. are governed by the meteorological conditions. The thesis deals with the study of the atmospheric dispersion capacity, wind climatology, atmospheric stability, pollutant distribution by means of a model and the suggestions for a comprehensive planning for the industrially developing city, Cochin. The definition, sources, types and effects of air pollution have been dealt with briefly. The influence of various meteorological parameters such as vector wind, temperature and its vertical structure and atmospheric stability in relation to pollutant dispersal have been studied. The importance of inversions, mixing heights, ventilation coefficients were brought out. The spatial variation of mixing heights studies for the first time on a microscale region, serves to delineate the regions of good and poor dispersal capacity. A study of wind direction fluctuation, σθ and its relation to stability and mixing heights were shown to be much useful. It was shown that there is a necessity to look into the method of σθ computation. The development of Gausssian Plume Model along with the application for multiple sources was presented. The pollutant chosen was sulphur dioxide and industrial sources alone were considered. The percentage frequency of occurrence of inversions and isothermals are found to be low in all months during the year. The spatial variation of mixing heights revealed that a single mixing height cannot be taken as a representative for the whole city have low mixing heights and monsoonal months showed lowest mixing heights. The study of ventilation co-efficients showed values less than the required optimum value 6000m2/5. However, the low values may be due to the consideration of surface wind alone instead of the vertically averaged wind. Relatively more calm conditions and light winds during night and strong winds during day time were observed. During the most of the year westerlies during day time and northeasterlies during night time are the dominant winds. Unstable conditions with high values of σθ during day time and stable conditions with lower values of σθ during night time are the prominent features. Monsoonal months showed neutral stability for most of the time. A study σθ of and Pasquill Stability category has revealed the difficulty in giving a unique value of for each stability category. For the first time regression equations have been developed relating mixing heights and σθ. A closer examination of σθ revealed that half of the range of wind direction fluctuations is to be taken, instead of one by sixth, to compute σθ. The spatial distribution of SO2 showed a more or less uniform distribution with a slight intrusion towards south. Winter months showed low concentrations contrary to the expectations. The variations of the concentration is found to be influenced more by the mixing height and the stack height rather than wind speed. In the densely populated areas the concentration is more than the threshold limit value. However, the values reported appear to be high, because no depletion of the material is assumed through dry or wet depositions and also because of the inclusion of calm conditions with a very light wind speed. A reduction of emission during night time with a consequent rise during day time would bring down the levels of pollution. The probable locations for the new industries could be the extreme southeast parts because the concentration towards the north falls off very quickly resulting low concentrations. In such a case pollutant spread would be towards south and west, thus keeping the city interior relatively free from pollution. A more detailed examination of the pollutant spread by means of models that would take the dry and wet depositions may be necessary. Nevertheless, the present model serves to give the trend of the distribution of pollutant concentration with which one can suggest the optimum locations for the new industries
Resumo:
The deteriorating air quality especially in urban environments is a cause of serious concern. In spite of being an effective sink, the atmosphere also has its own limitations in effectively dispersing the pollutants being dumped into it continuously by various sources, mainly industries. Many a time, it is not the higher emissions that cause alarming level of pollutants but the unfavourable atmospheric conditions under which the atmosphere is not able to disperse them effectively, leading to accumulation of pollutants near the ground. Hence, it is imperative to have an estimate of the atmospheric potential for dispersal of the substances emitted into it. This requires a knowledge of mixing height, ventilation coefficient, wind and stability of the region under study. Mere estimation of such pollution potential is not adequate, unless the probable distribution of concentration of pollutants is known. This can be obtained by means of mathematical models. The pollution potential coupled with the distribution of concentration provides a good basis for initiating steps to mitigate air pollution in any developing urban area. In this thesis, a fast developing industrial city, namely, Trivandrum is chosen for estimating the pollution potential and determining the spatial distribution of sulphur dioxide concentration. Each of the parameters required for pollution potential is discussed in detail separately. The thesis is divided into nine chapters.
Resumo:
Halobacteria, members of the domain Archaea that live under extremely halophilic conditions, are often considered as dependable source for deriving novel enzymes, novel genes, bioactive compounds and other industrially important molecules. Protein antibiotics have potential for application as preserving agents in food industry, leather industry and in control of infectious bacteria. Halocins are proteinaceous antibiotics synthesized and released into the environment by extreme halophiles, a universal characteristic of halophilic bacteria. Herein, we report the production of halocin (SH10) by an extremely halophilic archeon Natrinema sp. BTSH10 isolated from salt pan of Kanyakumari, Tamilnadu, India and optimization of medium for enhanced production of halocin. It was found that the optimal conditions for maximal halocin production were 42 C, pH 8.0, and 104 h of incubation at 200 rpm with 2% (V/V) inoculum concentration in Zobell’s medium containing 3 M NaCl, Galactose, beef extract, and calcium chloride as additional supplements. Results indicated scope for fermentation production of halocin for probable applications using halophilic archeon Natrinema sp. BTSH10
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Thermally stable materials with low dielectric constant (k < 3.9) are being hotly pursued. They are essential as interlayer dielectrics/intermetal dielectrics in integrated circuit technology, which reduces parasitic capacitance and decreases the RC time constant. Most of the currently employed materials are based on silicon. Low k films based on organic polymers are supposed to be a viable alternative as they are easily processable and can be synthesized with simpler techniques. It is known that the employment of ac/rf plasma polymerization yields good quality organic thin films, which are homogenous, pinhole free and thermally stable. These polymer thin films are potential candidates for fabricating Schottky devices, storage batteries, LEDs, sensors, super capacitors and for EMI shielding. Recently, great efforts have been made in finding alternative methods to prepare low dielectric constant thin films in place of silicon-based materials. Polyaniline thin films were prepared by employing an rf plasma polymerization technique. Capacitance, dielectric loss, dielectric constant and ac conductivity were evaluated in the frequency range 100 Hz– 1 MHz. Capacitance and dielectric loss decrease with increase of frequency and increase with increase of temperature. This type of behaviour was found to be in good agreement with an existing model. The ac conductivity was calculated from the observed dielectric constant and is explained based on the Austin–Mott model for hopping conduction. These films exhibit low dielectric constant values, which are stable over a wide range of frequencies and are probable candidates for low k applications.
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Spinel ferrites are commercially important because of their excellent magnetic and catalytic properties. The study by Low Energy Ion Scattering (LEIS) can reveal atomic scale information on the surface. The surface of selected spinel ferrites was investigated by LEIS. It has been found that it is the octahedral sites which are preferentially exposed on the surface of the spinel ferrites. So the probable planes which are exposed on spinel ferrite surfaces are D(110) or B(111). This prediction using LEIS gives scope for tailor-making compounds with catalytically active ions on the surface for various catalytic reactions.
Resumo:
Metglas 2826 MB having a nominal composition of Fe40Ni38Mo4B18 is an excellent soft magnetic material and finds application in sensors and memory heads. However, the thin-film forms of Fe40Ni38Mo4B18 are seldom studied, although they are important in micro-electro-mechanical systems/nano-electromechanical systems devices. The stoichiometry of the film plays a vital role in determining the structural and magnetic properties of Fe40Ni38Mo4B18 thin films: retaining the composition in thin films is a challenge. Thin films of 52 nm thickness were fabricated by RF sputtering technique on silicon substrate from a target of nominal composition of Fe40Ni38Mo4B18. The films were annealed at temperatures of 400 °C and 600 °C. The micro-structural studies of films using glancing x-ray diffractometer (GXRD) and transmission electron microscope (TEM) revealed that pristine films are crystalline with (FeNiMo)23B6 phase. Atomic force microscope (AFM) images were subjected to power spectral density analysis to understand the probable surface evolution mechanism during sputtering and annealing. X-ray photoelectron spectroscopy (XPS) was employed to determine the film composition. The sluggish growth of crystallites with annealing is attributed to the presence of molybdenum in the thin film. The observed changes in magnetic properties were correlated with annealing induced structural, compositional and morphological changes