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Extraction and Recovery of Various Wastewater Contaminants Using Liquid Membrane Techniques
No full textThis work demonstrates a systematic investigation on extraction and recovery performances of characteristically different species having environmental and industrial importance in Liquid Membrane (LM) transport. The investigated species were: lignosulfonate (LS), congo red (CR) and methylene blue (MB) dyes, hexavalent chromium and curcumin. One major objective of this work was to use renewable vegetable oils as the LM diluent or solvent (green solvents). In a typical bulk liquid membrane (BLM) experiment, detailed 2 and 3 phase studies were carried out for selection of suitable stripping agent, LM solvent, carrier along with estimation of optimum process conditions like carrier concentration, feed phase pH, feed and strip phase concentrations, phase ratios, temperature and stirring rate to maximize the extraction and recovery percentages of the targeted species. Additionally, kinetic estimation of data for individual species in the BLM transport was conducted. Highest extraction (E) and recovery (R) percentages of LS were measured at 92.4 and 75.2 respectively in sunflower oil/tri-n-octylamine (TOA) system using Na2SO4 of solution strength of 0.2 (M) as the stripping medium. 4 vol.% TOA concentration, feed phase pH~2 at 300 rpm stirring speed and 40oC temperature were the optimum manifold conditions with higher rate constants for stripping ( ) than extraction ( ) process, explaining extraction to be the rate determining step. Between %E and %R of two contrastingly different dyes viz. CR (anionic) and MB (cationic), it was observed that the transport of CR was favored using sunflower oil/TOA (4%) system with Na2CO3 (1 M) as effective stripping medium, leading to 99.9 %E and 75.6 %R. Meanwhile, MB reported a 95.2 %E and 92.4 %R using sunflower oil as solvent, phenol as carrier (1 M) and H2SO4 (1.25 M) as stripping medium. Interestingly, CR preferred a highly acidic feed medium (pH~2) whereas MB transport was effective in an alkaline feed condition (pH~12). BLM separation of hexavalent Cr showed maximum 99.2 %E and 94.8 %R using sunflower oil/TOA (2%) as LM medium and CH3COONa (0.2 M) as stripping medium. curcumin’s (or, Curcuma Longa) transport inside the BLM ensemble was most effective using sunflower oil as the diluent, TOA (4%) as carrier and NaOH (0.75 M) as the stripping agent. The overall %E and %R for curcumin was reportedly 99.7 and 96.5 respectively. Equilibrium distribution time for various investigated species were LS (3 h), CR (8 h), MB (8 h), Cr (VI) (2 h) and curcumin (2 h) 2 k 1 k respectively. The estimated values of activation energies for various species during extraction and recovery processes were: (36.85, 54.79 kJ mol-1) for LS, (45.92, 74.05 kJ mol-1) for CR, (25.87, 36.94 kJ mol-1) for MB, (118.71, 90.68 kJ mol-1) for Cr (VI) and (118.83, 109.54 kJ mol-1) for curcumin respectively. Subsequently, transport of LS and Cr (VI) via supported liquid membrane (SLM) was investigated where sunflower oil/TOA was immobilized on the porous network of hydrophobic polytetrafluoroethylene (PTFE) to be used as the membrane medium. LS reported E and R percentages of 90.7 and 64.2 respectively whereas Cr (VI) reported values of 97.6 (%E) and 94.4 (%R). The results were reproducible even after 12th cycle for Cr (VI) with each cycle lasting of 8 h. However, with LS, the results were reproducible upto 2 cycles (each cycle lasting for 12 h). The SLM were found to be stable for 8 (LS) and 15 (hexavalent Cr) experimental runs with 24 and 16 h between each run respectively. The emulsion liquid membrane (ELM) study with Cr (VI) yielded %E of 99.2 with very short (~ 5 min) equilibrium time. MIL-101 (Cr) metal organic framework (MOF) synthesized microwave route reported exceptionally high specific surface area (ca. 3075 m2g-1) and aqueous phase stability and high adsorptive loading for the targeted species viz. LS and CR. Adsorption sweep experiments showed an overall improvement in extraction percentage of LS from 92% (regular BLM study) to ca. 97%. The recovery percentage of LS was decreased from ca. 75% (regular BLM study) to <10% because of adsorption of LS from bulk stripping medium, leading to an increase in concentration gradient across LM-strip interphase. For CR, adsorption sweep had minimal influence in the overall transport vis-à-vis LS. Favorable chemistry of the stripping medium was found to be important for maintaining suitable pH conditions for the success of adsorption sweep process
Representation of the Self: Reading Sports Autobiographies
No full textAutobiographies, in general, have been defined as ‘life-writing’ and ‘denotes all modes and genres of telling one’s own life.’ It seeks to reconstruct the author’s personal story within a given ‘social, cultural, and historical framework’. Anybody who can write a sentence or speak to a ghost-writer or speak into a tape-recorder can offer an autobiography (Olney 3). However, lucid the narrative seems, it is the most elusive of all the literary forms as it is challenging for a critic to get a hold on it since there are no available general rules. Along with the elites and the subalterns, the protean nature of autobiographical genre has opened the gates for sportspersons too. Treated as stars, they remain in the public memory for a short time, till they achieve laurels in their sport. Research has established that earlier accounts of a sportsperson’s life lacked subjectivity as they were mere instructions related to their sports. Today it is a genre all by itself, which speaks about the lived experiences of its author in order to build a direct connection between the author and the reader. It stores a vast repository of social and cultural information of the times when the autobiography is penned and brings to life the contemporaneous happenings of the society as observed through the eyes of the narrator. Therefore, we can say that the ‘hero’ and ‘achieved celebrity’ status of a sportsperson provides his autobiography with extraordinary relevance. Sportspersons are perceived as idols who contain the power to influence and contribute a broad cultural significance to contemporary society. Hence unlike novels and biographies, readers carry a certain amount of expectation from the narrator of an autobiography which makes the author’s act transactional and performance oriented. This thesis understands that autobiography is a performance and explores the incidents and memories focused by the narrators to progress their stories. Their autobiographies reveal the unique configurations of memory, identity, and culture very clearly. The notion of identity that emerges is not essentialist rather strategic and positional. The autobiographies that have been selected for analyses are, Milkha Singh’s The Race of My Life, M.C Mary Kom’s Unbreakable, Saina Nehwal’s Playing to Win, Abhinav Bindra’s A Shot at History, Sania Mirza’s Ace against Odds and PT Usha’s The Golden Girl. All these auto-biographers are recipients of the country’s highest sports honours and are trailblazers of their sport. The authors chosen all play individual sports, and they are the only Indian elite sports stars playing individual sport who have written autobiographies till date. These sportspersons have represented India internationally in athletics, boxing, badminton, shooting, and tennis. Other available Indian sports autobiographies are of players playing group sport, especially cricket. In the last decade, the country has witnessed the publication of quite a few cricket autobiographies. Cricket is the most popular sport in India, almost practised as a ‘religion’ and in the process, most of the struggles of the individual sportspersons go unnoticed. The main difference between players playing individual sport and group sport is that in individual sport the success and failure are solely borne by the sportsperson, while in group sport it gets divided among the players. Hence the focus of this study is on autobiographies written by individual sportspersons, by looking at the way they have portrayed themselves to their readers. This thesis argues that Indian sports autobiographies are performances of the sportsperson’s individual choice, athletic identity, and family narrative, and these remain at the centre of their consciousness when they develop their autobiography
Low Temperature Sintering and Characterizations of Co-Ti Substituted SrFe12O19 M-type Hexagonal Ferrites for High frequency Antenna Applications
No full textThe objective of the work was to sinter the Co-Ti substituted SrFe12O19 ferrite at 900oC using sintering additives and to use the low-temperature sintered ferrite for high frequency antenna substrate materials applications. SrCo1.5Ti1.5Fe9O19 ferrite was synthesized by two different routes; (a) sol-gel combustion and (b) solid-state reaction. Although the properties of the ferrite synthesized by sol-gel route were marginally higher than the ferrite prepared by solid state route, the ferrite synthesized by solid state route was used for low temperature sintering experiments due to its economical and simple processing technique. The different sintering additives like; (a) B2O3, (b) Bi2O3/+B2O3, (c) B2O3+CuO/ZnO, and (d) B2O3-Bi2O3-SiO2-ZnO (BBSZ) glass were used to study the sintering behavior of SrCo1.5Ti1.5Fe9O19 ferrite at 900oC. The 5wt% B2O3 sintering additive was proposed for the ferrite, which provides bulk density ~4.0 g/cc, equivalent ε~17 and μ~18, higher miniaturization factor (n=17.49) and good impedance matching (Zi=1.02). Bi2O3 or (Bi2O3+B2O3) additives were not so efficient like 5wt% B2O3 additive. The ferrite containing 5wt% Bi2O3 showed comparatively lower properties like; bulk density ~3.57 g/cc, ε~12.5, μ~13, n=12.74, and Zi=1.01. In the case of different combinations of B2O3+ZnO/CuO additives, 4wt% B2O3+6wt%ZnO (4B6Zn) composition was found efficient with respect to only higher bulk density achievement (~4.62 g/cc), as ε (~13) and n (~14.4) values were lower compared to 5wt% B2O3 added ferrite. The 5wt% BBSZ glass additive was found equally effective like 5wt% B2O3 additive, where the bulk density ~ 4.3 g/cc, n = 17.5 and Zi = 0.99 and about equivalent ε and μ (~17.5) were achieved. For comparison with SrCo1.5Ti1.5Fe9O19 ferrite, BaCo1.5Ti1.5Fe9O19 ferrite was also synthesized and low temperature sintered using 5wt% B2O3 and 5wt%. BBSZ glass additive. The BBSZ glass additive was found more efficient than B2O3 additive for BaCo1.5Ti1.5Fe9O19 ferrite. Finally, microstrip-fed cylindrical antennas based on low-temperature sintered SrCo1.5Ti1.5Fe9O19 and BaCo1.5Ti1.5Fe9O19 ferrites were designed, fabricated and characterized. BBSZ glass containing SrCo1.5Ti1.5Fe9O19 ferrite showed the antenna parameters; return loss ~ -34 dB, gain ~ 5.23 dB, VSWR ~ 1.05 and bandwidth (S11<-10dB) of 133 MHz at fr ~ 10.45 GHz. In the case of BBSZ glass containing BaCo1.5Ti1.5Fe9O19 ferrite, the return loss ~ -32 dB, VSWR ~ 1.03 and bandwidth of 98 MHz were found at fr ~ 8.91 GHz. The demonstrated results indicate that 5wt% B2O3 and 5wt%. BBSZ glass assisted low temperature sintered SrCo1.5Ti1.5Fe9O19 ferrite will be a better candidate for high-frequency antenna substrate material application
Synthesis and Characterizations of Magnetoelectric Materials Processed by Microwave Assisted Solid State Reaction Route for Multifunctional Device Applications
No full textMagnetoelectric (ME) composites, in which magnetic field can modify electrical properties and electric field can modify magnetic properties, are one of the promising as well as technologically interesting materials. Research work on bulk ME composites is based on the principle of combining highly electrostrictive material with highly magnetostrictive one in the anticipation of pronounced ME effect. ME effect in a composite is thought to take place mainly via mechanical coupling through piezoelectric and magnetostriction effects. Lack of inherent coupling in single-phase multiferroic compounds at room temperature led to the introduction of two-phase composite systems in which ME effect is regarded as the product property. Enhanced ME effect or better magneto-dielectric property between electrostrictive and magnetostrictive phases can be achieved in multiferroic composites. Hence, proper selection of electrostrictive and magnetostrictive phases is important to get better ME composite systems for multifunctional device applications. Thus, in view of the potential applications of ME materials, this work focuses on synthesizing ME composites comprising of ferrite (magnetostrictive) and ferroelectric (electrostrictive) phases by microwave-assisted solid-state reaction route. In order to synthesize bulk ME composites, morphotropic phase boundary composition (MPB) of 0.93Bi0.5Na0.5TiO3-0.07BaTiO3 (BNT-BT) and 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) have been selected as electrostrictive phase whereas Ni0.30Cu0.08Zn0.62Fe2O4 (NCZF) and CoFe2O4(CFO) have been selected as the magnetostrictive phase. The parent systems were individually prepared and different wt. % of each of magnetostrictive and electrostrictive phases were mixed resulting in the formation of different composite systems. ME composites, synthesized via microwave assisted solid state reaction route (SSRR), are as follows:
1. (1-x)(BNT-BT)-xNCZF (where x = 0.1, 0.2, 0.3, 0.4, 0.5 wt. %)
2. (1-x)(BNT-BT)-xCFO (where x = 0.1, 0.2, 0.3, 0.4, 0.5 wt. %)
3. (1-x)(BZT-BCT)-xNCZF (where x = 0.1, 0.2, 0.3, 0.4, 0.5 wt. %)
4. (1-x)(BZT-BCT)-xCFO (where x = 0.1, 0.2, 0.3, 0.4, 0.5 wt. %)
XRD patterns of microwave calcined and sintered BNT-BT and BZT-BCT electrostrictive samples showed single perovskite phase. Experimental density of sintered BNT-BT and BZT-vii BCT samples was found to be ~94.96% and ~94.31% of their theoretical density, respectively. Average grain size (from SEM microstructure study) of microwave sintered BNT-BT and BZT-BCT samples was found to be ~0.41 μm and ~0.33 μm, respectively. Cole-Cole plots of BNT-BT and BZT-BCT samples in the 300ºC- 450ºC temperature range revealed negative temperature coefficient of resistance (NTCR) behaviour. Polarization vs. electric field (P-E) loop study of BNT-BT samples showed saturation polarization (Ps) and remnant polarization (Pr) to be ~ 23μC/cm2 and ~12μC/cm2,respectively and coercive field (Ec) was obtained ~ +/-15kV/cm. For BZT-BCT samples, Ps, Pr, Ec were obtained to be ~ 12μC/cm2, ~ 5μC/cm2 and ~ +/-8kV/cm, respectively. Leakage current of BNT-BT and BZT-BCT samples lies in 10-5-10-6 amps and in 10-7-10-8 amps range, respectively. Single phase cubic structure was obtained from XRD study of NCZF and CFO samples. Average grain size for NCZF and CFO samples were found to be ~0.30 μm and ~0.29 μm respectively. Room temperature dielectric study revealed that dielectric constant (εr) decreased with the increase in frequency whereas, εr for both the samples has been found to increase with the increase in temperature. Both the samples showed NTCR behaviour, which is evident from Cole-Cole plot study. Leakage current value of NCZF and CFO samples was obtained in 10-5-10-6 amps and in 10-4-10-5 amps range, respectively. Saturation magnetization (Ms) of NCZF and CFO samples was observed to be~ 45emu/g and ~ 60emu/g, respectively. From P-E loop study of (1-x)(BNT-BT)-xNCZF and(1-x)(BNT-BT)-xCFO composite samples it was found that with the increase of NCZF and CFO contents in value of 2Pmax and 2Pr vary and became maximum for x = 0.4. However, 2Pmax and 2Pr values of 0.6(BNT-BT)-0.4NCZF composite system were found more compared to 0.6(BNT-BT)-0.4CFO composite system. In M-H loop study, it was observed that with the increase of ferrite content (NCZF and CFO) in BNT-BT matrix, Ms and Mr values increased. Ms ~37.8 emu/g and Mr ~9.83 emu/g were obtained in 0.5(BNT-BT)-0.5CFO composite samples. P-E loop study of (1-x)(BZT-BZT)-xNCZF and(1-x)(BZT-BCT)-xCFO composite samples revealed that with the increase of NCZF as well as CFO contents in BZT-BCT matrix, value of 2Pmax and 2Pr vary and become maximum for x = 0.2. However, 2Pmax and 2Pr values were found to be maximum for 0.8(BZT-BCT)-0.2CFO composite samples.M-H loop study showed that with the increase of ferrite content (NCZF and CFO) in BZT-BCT matrix, Ms and Mr values increased for both (1-x)(BZT-BCT)-xNCZF and(1-x)(BZT-BCT)-xCFO composite system. However maximum Ms and Mr were observed in 0.5(BZT-BCT)-0.5CFO composite samples. Besides having good electrical and magnetic properties, there should be better interaction between the ferroic orders in ME composite samples. This interaction can produce other functionalities in electronic devices such as sensors, transducer, oscillators, filters, phase shifters, memory devices etc. From the analysis of present work, it can be inferred that 0.6(BNT BT)-0.4NCZF, 0.6(BNT-BT)-0.4CFO, 0.8(BZT-BCT)-0.2NCZF, 0.8(BZT-BCT)-0.2CFO composite system showed better polarization and magnetization values. Leakage current of 0.8(BNT-BT)-0.2CFO samples was found to be least. In all ME composite samples, AC conductivity increased with the increase of temperature. Grain and grain boundary contributions of synthesized composite samples were inferred from fitted Cole-Cole plot. NTCR behaviour and non-Debye type relaxation have been confirmed in all composite samples. From PFM and MFM analysis, we found evidence of M-E coupling in the composite samples. MD% (at 100 kHz) has been obtained to be ~ 2.4%, 4.7%, 3.2%, 6% for 0.6(BNT-BT)-0.4NCZF, 0.6(BNT-BT)-0.4CFO, 0.8(BZT-BCT)-0.2NCZF, 0.8(BZT-BCT)-0.2CFO composite samples, respectively. Overall, high M-D coupling has been observed in 0.8(BZT-BCT)-0.2CFO composite samples. Observance of high MD effect at low frequency (100 Hz) also suggested the presence of intrinsic ME coupling in studied composite samples
Educating First-Generation Tribal Learners in Urban English Medium Schools: ELT Strategies to Bridge the Gap
No full textInternet and globalisation have ensured English of its place as the most sought-after language the world over. Today in India, English is perceived not just as a language but as a path for upward social mobility, economic betterment and a ‘powerful agent for social change’ by the urban and rural populace alike. Tribal communities in India have historically been marginalised sections of the society. Despite several measures to bring about equality, inequalities exist and become more prominent with reference to English language learning. A recent trend in English education in India is the shift from ELT to English as a medium of Instruction (EMI), and state governments are routinely introducing EMI in state supported schools. A serious attempt towards mainstreaming children from deprived tribal communities through EMI was attempted by the Government of Odisha in the academic year 2015-16, through an innovative scheme called Anwesha (quest). In the backdrop of such an educational model being proposed for the first time it is imperative that independent studies are conducted to know the on-the-ground situation and thereby suggest corrective measures. This study had four major objectives. Firstly, to find out the perceptions of various stakeholders - students, their parents, teachers, and administrators - regarding a unique state-supported beneficial scheme called Anwesha that enables tribal children from Below Poverty Line (BPL) families in rural areas to study in private English medium schools in urban areas. Secondly, to identify the problem areas in English learning for the young tribal learners, and to prepare the tribal learners directly taking admission in grade I under the Anwesha scheme to learn a vocabulary list of 500 English words through a bridging course, as these children had missed out on three crucial years of formal exposure to English at the kindergarten level. Thirdly, to examine if the use of tribal folklore as English learning material has a motivating effect on young tribal learners and lastly to understand how tribal artefacts from learners’ own culture can be used for curriculum planning in English language education. To achieve the various objectives of the study a mixed methods research approach was adopted by making use of both qualitative and quantitative methods. Data collection for this study has been done through a diagnostic test, face to face interviews, focus group discussions and classroom observations. This study has been conducted in three different phases between September 2016 and April 2018. The diagnostic test was helpful in identifying the key weaknesses of the first-generation tribal learners who are being educated in urban English medium schools. The bridging course used in the study was helpful in improving the performance of the tribal learners who were being admitted directly in Class I. But even after going through the bridging course, it was not at par with the performance of the learners who have been in English medium schools right from nursery level. The findings of this study justify the need for a bridging course for tribal children being admitted directly in Class I in urban English medium schools. The findings reveal that tribal learners show a clear preference for ELT material with content drawn from the tribal milieu. Based on the findings of this study it is recommended that schools admitting students under the Anwesha scheme must consider introducing the bridging course for these students before they are introduced their prescribed course. It is also recommended that school authorities should consider introducing alternative course material for the students admitted under Anwesha scheme with content drawn for tribal folklore. Since the study was conducted on a very small scale combined with the fact that there were many external factors which were beyond the control of the researcher, the findings of this study are indicative and cannot be generalised. It is believed that the findings of this study would add to the research in the field of ELT, and further studies could be taken up in related topics. With the changing status of English in India, and with more and more state governments making provision for English medium education for the economically and socially deprived sections of the society, more number of first-generation learners would certainly be introduced to English medium instruction in the coming years. Thus, the findings of this study and the recommendations made would be found useful in framing policies, designing course content, and formulating classroom strategies for situations where first-generation learners are offered English medium education
Educating First-Generation Tribal Learners in Urban English Medium Schools: ELT Strategies to Bridge the Gap
No full textInternet and globalisation have ensured English of its place as the most sought-after language the world over. Today in India, English is perceived not just as a language but as a path for upward social mobility, economic betterment and a ‘powerful agent for social change’ by the urban and rural populace alike. Tribal communities in India have historically been marginalised sections of the society. Despite several measures to bring about equality, inequalities exist and become more prominent with reference to English language learning. A recent trend in English education in India is the shift from ELT to English as a medium of Instruction (EMI), and state governments are routinely introducing EMI in state supported schools. A serious attempt towards mainstreaming children from deprived tribal communities through EMI was attempted by the Government of Odisha in the academic year 2015-16, through an innovative scheme called Anwesha (quest). In the backdrop of such an educational model being proposed for the first time it is imperative that independent studies are conducted to know the on-the-ground situation and thereby suggest corrective measures. This study had four major objectives. Firstly, to find out the perceptions of various stakeholders - students, their parents, teachers, and administrators - regarding a unique state-supported beneficial scheme called Anwesha that enables tribal children from Below Poverty Line (BPL) families in rural areas to study in private English medium schools in urban areas. Secondly, to identify the problem areas in English learning for the young tribal learners, and to prepare the tribal learners directly taking admission in grade I under the Anwesha scheme to learn a vocabulary list of 500 English words through a bridging course, as these children had missed out on three crucial years of formal exposure to English at the kindergarten level. Thirdly, to examine if the use of tribal folklore as English learning material has a motivating effect on young tribal learners and lastly to understand how tribal artefacts from learners’ own culture can be used for curriculum planning in English language education. To achieve the various objectives of the study a mixed methods research approach was adopted by making use of both qualitative and quantitative methods. Data collection for this study has been done through a diagnostic test, face to face interviews, focus group discussions and classroom observations. This study has been conducted in three different phases between September 2016 and April 2018. The diagnostic test was helpful in identifying the key weaknesses of the first-generation tribal learners who are being educated in urban English medium schools. The bridging course used in the study was helpful in improving the performance of the tribal learners who were being admitted directly in Class I. But even after going through the bridging course, it was not at par with the performance of the learners who have been in English medium schools right from nursery level. The findings of this study justify the need for a bridging course for tribal children being admitted directly in Class I in urban English medium schools. The findings reveal that tribal learners show a clear preference for ELT material with content drawn from the tribal milieu. Based on the findings of this study it is recommended that schools admitting students under the Anwesha scheme must consider introducing the bridging course for these students before they are introduced their prescribed course. It is also recommended that school authorities should consider introducing alternative course material for the students admitted under Anwesha scheme with content drawn for tribal folklore. Since the study was conducted on a very small scale combined with the fact that there were many external factors which were beyond the control of the researcher, the findings of this study are indicative and cannot be generalised. It is believed that the findings of this study would add to the research in the field of ELT, and further studies could be taken up in related topics. With the changing status of English in India, and with more and more state governments making provision for English medium education for the economically and socially deprived sections of the society, more number of first-generation learners would certainly be introduced to English medium instruction in the coming years. Thus, the findings of this study and the recommendations made would be found useful in framing policies, designing course content, and formulating classroom strategies for situations where first-generation learners are offered English medium education
Modeling and Simulation of Dual Metal Quadruple Gate (DMQG) MOSFETs
No full textIn an ever-increasing need for higher current drive and better short-channel characteristics, Silicon-On-Insulator (SOI) Metal-Oxide-Semiconductor (MOS) transistors are evolving from classical, planar, single-gate devices into three-dimensional devices with multiple gates. Multiple-gate (MuG) MOSFET structures can achieve superior electrostatic integrity than the conventional bulk MOSFET structure and hence offer a pathway to lower drain voltage, reduced threshold voltage,and extended transistor scaling.Among the MuG MOSFETs, quadruple gate (QG) MOSFETis the most promising structure as the channel remains surrounded by four gates, which provide ultimate control over the charge carrier in the channel region. In this thesis, we are intended to analytically analyze the subthreshold characteristics of dual-metal quadruple gate (DMQG) MOSFETs. In brief, attempts have been made to present analytical models for threshold voltage,drain-induced barrier lowering (DIBL), subthreshold current, and subthreshold swing parameters for DMQG MOSFETs in nanometer regime.Moreover, attempts have also been made to presentthe analytical models of subthreshold characteristics of ultra-thin DMQG MOSFETsby considering the quantum confinement effects.The model results are analyzed with wide variations in the device parameters like gate metal work functions, channel cross-section (width × height), channel length, oxide thickness, and gate length ratios.Further, the analytical modeling of drain current, transconductance, and drain conductance characteristics have been presented forDMQG MOSFETs.Finally, The cut-off frequency () and the maximum frequency of oscillation () of the proposed structure are analyzed in detailfor RFcircuitsandsystems.The validity of the analytical models is verified by comparing model results with the numerical simulation results obtained from ATLAS™, a device simulator from SILVACO Inc
A Study on Clouds, Precipitation and Radiation Response to Aerosols Over Different Parts of Indian Region
No full textAtmospheric aerosols are one of the most complex and uncertain constituents due to their significance in governing weather and climate over a particular region besides health impacts. Cloud droplets form in the presence of aerosol particles acting as CCN (Cloud Condensation Nuclei). Aerosol concentration may influence the droplets' number in clouds, associated radiation fluxes, and consequent precipitation. The study presented in this thesis considers satellite-based observations of aerosols and clouds combined with other datasets and WRF-Chem outputs to examine how aerosols influence cloud properties, radiation, and precipitation over different parts of the Indian region. Several aerosols, clouds, and meteorological parameters considered for the study. The primary variables considered for the study include aerosol optical depth (AOD), angstrom exponent (AE), cloud effective radius (CER), cloud fraction (CF), cloud optical depth (COD), cloud top pressure (CTP), cloud water path (CWP), relative humidity (RH), lower-tropospheric stability (LTS), vertical velocity (VV), wind speed (WS), shortwave cloud radiative forcing (SWCRF), longwave cloud radiative forcing (LWCRF), net cloud radiative forcing (NetCRF) and rainfall.
In the pre-monsoon months, AOD was found to be moderate to high over Indo-Gangetic Plains (IGP) and coastal regions and low over central, western, and southern parts of the Indian region. Low to significant values of AOD was seen over some parts of IGP and north-eastern Indian region during post-monsoon and winter, indicating the dominance of anthropogenic production and biomass and fossil fuel burning. The trend analysis implies a significant increase in anthropogenic aerosols over the Indian region during all the seasons..
Static and Dynamic Analysis of Imprecisely Defined Systems with Uncertain Parameters
No full textPractical problems of various disciplines viz. structural mechanics, robotics, control theory, image processing, stationary analysis of circuits etc. deal with mathematical models often governed by differential equations. Usually, the material properties (or the coefficients of the differential equations) are considered as crisp. But, in actual practice only bounds of values are obtained as a result of errors in measurements, observations and calculations or due to maintenance induced errors etc. These uncertain bounds may be modeled using probabilistic methods, interval computations and fuzzy set theory. In probabilistic approach, the uncertain parameters are considered as random variables whereas in interval and fuzzy computations, the parameters are treated as closed intervals of real line and fuzzy numbers respectively. When only lower and upper bounds of parameters are considered, interval computations may be advantageous as compared to probabilistic approach (which requires sufficient experimental data). Moreover, interval analysis is a tool for studying propagation of fuzzy uncertainties in term of fuzzy intervals using r-cut. As regards, interval computing acts as a robust tool for handling uncertainty propagation in systems having imprecise parameters.
Few authors have developed methods in handling imprecisely defined systems with interval and fuzzy uncertainties. But, existing methods are either problem dependent or result to weak solutions. Also, the existing methods and techniques are sometimes silent about the overestimation problems that occur due to `dependency effect' in interval computations. In this regard, concepts of classical Interval Arithmetic (IA), contractors and parametric approach have been used in this investigation for handling interval uncertainties. In particular, imprecisely defined systems with interval and fuzzy parameters have been modeled here using system of linear equations, eigenvalue problems, constraint satisfaction problems for localization of robots, nonlinear oscillators and system identification problems.....
Partial Characterization of Halotolerant Microbial Cellulases and Their Application in Bioethanol Production Using Sea Water System
No full textDecreasing fossil fuel reservoir and increasing environment issues has triggered biofuel research. Lignocellulosic biomass is the most abundantly available biomass on earth with immense potential to meet global energy demands in a sustainable manner. Enzymatic hydrolysis of lignocellulosic biomass is advantageous than chemical hydrolysis because of environmental friendly nature and higher glucose yield without production of fermentation inhibitors. Cellulases are critical enzymes in biofuel and food industries. Several studies have been carried out on saccharification ability of bacterial and fungal cellulase. However, all these works have been carried out using fresh water based medium. Recent public threats on fresh water depletion signify the exploration of non-freshwater medium for the production of biofuels. Among the non-freshwater sources, seawater is the best source to be studied as a medium for biomass conversion due to its abundant availability in India. Utilization of halotolerant microorganisms capable of producing salt-tolerant enzymes will be a breakthrough in this field as they can tolerate high salt levels and ionic liquids better than current bacterial and fungal cellulases. Further, there will be advancement in use of sea and brackish water for biomass conversion. The present study focused on isolation and screening of bacterial strains from Gopalpur, Odisha, India capable of producing halotolerant cellulases. All the isolates were screened for their cellulolytic ability, and their enzymatic properties were characterized using soluble cellulose sources in fresh as well as in seawater. Cellulase produced by Bacillus oceanisediminis, Brevibacterium halotolerans, Psychrobacter celer, Pseudomonas aeruginosa, and Bacillus subtilis was characterizedfor different parameters like optimal pH, temperature, and substrate concentration. The optimal pH was found to be at 7.0, and optimal temperature was recorded to be between 50-60°C. The value of Km was 0.5, 0.7, 1.4, 1.3, and 0.3 mg/mL for B. oceanisediminis, B. halotolerans, P. celer, P. aeruginosa, and B. subtilis, respectively. Out the five isolates best three i.e. B. oceanisediminis, B. halotolerans, and P. Celer were selected for further analysis. All the enzymes from the three potent isolates were purified and analyzed for determination of molecular weight by SDS-PAGE and LC-MS studies and were found to be 42, 38, and 53 kDa for B. oceanisediminis, B. halotolerans, and P.celer, respectively. CD spectroscopy and bioinformatics studies were performed for the determination of secondary structure.The purified cellulase samples from B. oceanisediminis, B. halotolerans and P. celer has a characteristics antiparallel β-sheets, α-helix and type I β-turn in the secondary structures respectively. The crude enzyme extract and vii
direct bacterial cultures were independently utilized for saccharification of pretreated rice straw and the treated rice straw was characterizedfor theproduction of reducing sugars using HPLC. The Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy analysis was performed to assess the possible bond breakage and formation during saccharification of cellulose.The pretreated rice straw biomass on treatment with cellulase enzymes by the three halotolerant strains generated strong peaks which were evident at 1033 cm-1 (glucose), 2266 cm-1 (cellulose) and 1465, 1510, and 1600 cm-1 (lignin). The relative fraction and size of crystallites in cellulose was evaluated by X-ray diffraction (XRD) study. The crystallinity of pretreated rice straw was recorded as 59.073%, which decreased to 40.25%, 37.25% and 36.05% on treatment with B. oceanisediminis, B. halotolerans, and P. celer cellulases in freshwater, respectively. However, on treatment with cellulase in the seawater-based system, the crystallinity for B. oceanisediminis, B. halotolerans, and P. celer cellulases was found to be 51.58%, 79.34% and 49.21%, respectively. The saccharified biomass was further utilized for production of bioethanol in fresh water and seawater-based media using Saccharomyces cerevisiae NCIM 3570 and Dekkera naardenensis NCIM 3575. The resulting ethanol concentration in D. Naardenensis was disappointing, contradictory to that S. cerevisiae yielded excellent results with 9.79 g/L and 10.19 g/L in seawater and fresh water, respectively. Performance of S. cerevisiae remains unaffected in seawater and establishes it to one of the promising organisms for fermentation