42 research outputs found
Decentralising Bengaluru Urban -The Regional Planning way
No full textDecentralising Bengaluru Urban -The Regional Planning way
Author / Authors : Priyadarshini Sen
Page no.139 -148
Discipline : Applied Economics/ Management/ Commerce/Geography
Script/language : Roman/English
Category : Research paper
Keywords: Regional Planning, Metropolis, Social wellbeing, Settlement
Quantitative detection of pathogen load of Fusarium oxysporum f. sp. ciceris infected wilt resistant and susceptible genotypes of chickpea using intergenic spacer region-based marker
No full textNot AvailableQuantitative detection of pathogen DNA load is a crucial aspect in development of disease management strategies and breeding programs. In recent years, there have been several reports where formae speciales specific intergenic spacer (IGS) sequence based markers have been used for quantification of pathogen DNA in different plant and soil samples, through quantitative real-time PCR (qPCR). In the present study, we have utilized an IGS based marker, ISR 52, to detect and quantify Fusarium oxysporum f.sp. ciceris (Foc) DNA, using both conventional PCR and qPCR, in chickpea genotypes which contrast for resistance to Fusarium wilt. Our study reveals that the Foc DNA load was found to be significantly higher in the early wilting genotypes as compared to the wilt resistant genotypes. Late wilting genotype showed a spike in pathogen DNA load in later stage of plant growth. Phenotypic observation of disease progression in combination with qPCR data validated that the pathogen undergoes incubation period before manifestation of symptoms. The above observations provide evidence about the differential dynamics of pathogen build up inside different hosts during different time periods and probable reason for the earliness, lateness and resistance in wilting like traits in these genotype
Understanding the effects of promoters on the direct synthesis of hydrogen peroxide over supported palladium catalysts
No full textH2O2 is an active and selective oxidant that can be an environment-friendly replacement for toxic industrial oxidants such as Cl2 and other chlorine-based oxidants. The current industrial H2O2 production process, the anthraquinone autoxidation (AO), requires significant energy and capital expenditure due to the extensive purification and concentration steps. This makes H2O2 cost-prohibitive for many oxidation processes as compared to Cl2 which is inexpensively obtained from the chlor-alkali process. The direct synthesis of H2O2 (H2 + O2 → H2O2) is a potentially less expensive and energy-consumptive alternative to the incumbent anthraquinone autoxidation process. However, the formation of H2O by the reaction of H2 and O2 is thermodynamically favored over the formation of H2O2 on most transition metal catalysts which lowers the H2O2 selectivity of direct synthesis. Hence, significant research has been directed towards improving H2O2 selectivity through various methods (addition of promoters, alloying Pd with other transition metals). The addition of promoters (e.g., inorganic acids, halide salts) is a common method to improve H2O2 selectivity and several studies have investigated the effect of the addition of a cocktail of promoters on H2O2 rates and selectivities. However, very few studies have illustrated the fundamental way in which these promoters affect catalysis on the surface. The aim of this work is to provide a fundamental understanding of how certain promoters affect H2O2 rates and selectivities through rigorous experimental procedures and analysis.
The addition of inorganic acids (e.g., HCl, H2SO4, H3PO4) improve H2O2 selectivities, yet they also lead to the dissolution of Pd from the support. Under acidic conditions, Pd can exist in heterogeneous (Pd0) as well as homogeneous (Pd2+) forms and both these forms of Pd can potentially contribute to catalysis. In chapter 2, we demonstrate, by a combination of kinetic measurement and in situ UV-Vis spectroscopy, that the heterogeneous Pd0 nanoparticles are responsible for the H2O2 formation and H2O2 hydrogenation reactions under semi-batch conditions in presence of HCl. Introducing HCl into the reaction solution decrease the rates of H2O2 hydrogenation. Chloride adsorbs on the surface of the dispersed Pd nanoparticles, modifying the surface properties of the catalytically active Pd0 species, which are responsible for the reduction in H2O2 hydrogenation and hence increase the selectivity of H2O2. The homogeneous complexes (e.g., [PdCl4]2- and [PdCl3(H2O)]-) do not play a significant role in improving the selectivity of the reaction in both water and methanol solvent. These findings will help in understanding the role played by different promoters such as acids and halides in improving the H2O2 selectivity for direct synthesis.
In chapter 3, we examine another ubiquitous promoter for direct synthesis reaction, NaBr. Many studies exist that demonstrate that H2O2 selectivities are greater in presence of NaBr and an inorganic acid. Chapter 3 shows that variation of NaBr concentrations (in water solvent in the absence of a second promoter) increases H2O2 selectivities. Contact with NaBr solutions irreversibly modifies Pd nanoparticles, yielding higher H2O2 selectivities, due to the presence of strongly bound Br*-atoms. Bromide adsorption isotherms show that reduced Pd nanoparticles adsorb well over a monolayer of Br*-atoms, which suggests Br saturates surface Pd and subsequently intercalates within the near-surface region of Pd nanoparticles. Infrared spectra of adsorbed CO imply that Br atoms bind preferentially to under coordinated sites while ex situ X-ray photoelectron spectroscopy (XPS) indicates that these Br*-atoms withdraw charge from Pd atoms and yield larger fractions of Pd2+. H2O2 and H2O, both in the presence and absence of Br*-atoms, form via elementary steps that involve H2O-mediated proton-electron transfer (PET). Consequently, increased selectivities on Br*-modified surfaces reflect differences in apparent activation enthalpies for H2O2 (Δ〖H^‡〗_(H_2 O_2 )) and H2O (Δ〖H^‡〗_(H_2 O)) formation. Δ〖H^‡〗_(H_2 O_2 ) and Δ〖H^‡〗_(H_2 O) increase systematically with [NaBr], although with different sensitivities on [NaBr] indicating that Br*-atoms alter the electronic structure of Pd. The irreversible adsorption of Br atoms on Pd and their effects on H2O2 and H2O rates and H2O2 selectivities provide valuable insights into the role of Br in affecting direct synthesis.
We continue the exploration of different strategies to improve H2O2 selectivities and investigate the effect of incorporating methylphosphonic acid (MPA) on the catalyst and in the solvent in chapter 4. SiO2 supported Pd nanoparticles modified with methylphosphonic acid gave higher H2O2 selectivities as compared to unmodified Pd while H2O2 turnover rates remained almost constant. The H2O2 selectivity was further enhanced when MPA was introduced into the water solvent indicating that MPA in the solvent can act as a promoter and improve H2O2 selectivity. MPA binds irreversibly to the catalyst over the timescales of the experiment (~60 h) since the selectivity remained constant after flushing with water. MPA-functionalized SiO2 and MPA functionalized Pd-SiO2 both show increase in the density of acidic functions, however, there is a greater distribution of acidic functions on SiO2 as compared to Pd-SiO2 indicating that majority of the ligand was bound to the support and not adsorbed on Pd. The activation enthalpies for H2O2 and H2O formation do not change with the introduction of ligands either on the support or in the solvent (or both) indicating that the electronic structure of Pd is not perturbed due to the presence of the MPA ligand. Instead, a decrease in the local pH of the catalyst is likely responsible for the increase in H2O2 selectivities.
The rigorous kinetic measurements complemented with the thorough characterizations of catalyst provide insight into how different promoters alter the local environment and coordination of catalytically active Pd and influence the direct synthesis of H2O2. The combination of these techniques shows how surface properties of catalysts control the rates and selectivities, thus guiding the rational design of active, selective, and stable catalysts for the direct synthesis of hydrogen peroxide.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-12-01The student, Pranjali Priyadarshini, accepted the attached license on 2020-10-27 at 13:34.The student, Pranjali Priyadarshini, submitted this Dissertation for approval on 2020-10-27 at 13:46.This Dissertation was approved for publication on 2020-10-30 at 09:45.DSpace SAF Submission Ingestion Package generated from Vireo submission #15850 on 2021-03-04 at 16:19:24Made available in DSpace on 2021-03-05T21:40:41Z (GMT). No. of bitstreams: 2
PRIYADARSHINI-DISSERTATION-2020.pdf: 2801446 bytes, checksum: d7ca4e6a2b23b6d607edaa452d09224c (MD5)
LICENSE.txt: 4219 bytes, checksum: be2c96906229125cdaa01bd15a67b3a1 (MD5)
Previous issue date: 2020-10-30Embargo set by: Seth Robbins for item 117190
Lift date: 2023-03-05T21:40:52Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 117190
Lift date: 2023-03-05T21:43:00Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Onl
Biomass gasification in a novel 50 kWth bubbling fluidized bed steam reformer: Kinetic Model Optimization and Preliminary Evaluation of Product Gas Recycle and Process Conditions for Methanol Production
No full textMeeting the ever-increasing energy demands in our planet where conventional sources of energy are finite and fast depleting, controlling adverse phenomena like climate change, soil erosion, greenhouse gas emission, ozone layer thinning and pollution will remain profound challenges until widespread adoption of sustainable sources of energy is achieved. The shift to a sustainable energy system cannot be complete without the contribution of biomass energy. Within the ecosystem of biomass energy, gasification is a thermochemical conversion process undertaken to obtain a high-quality product gas by increasing the low energy density of solid biomass. The product gas can be used in power applications or be converted to liquid fuels for transportation. Gasification is carried out at high temperatures (700-1500°C) by using a gaseous agent under sub stoichiometric conditions (R.A. Kersten & De Jong, 2015). The main non-condensable permanent gases obtained from gasification are CO, H2, CO2 and CH4. Use of allothermal gasifiers, whose working is based on the separation of combustion and gasification chambers within the gasifier, with heat supply for carrying out endothermic reactions, established via heat carrier or heat exchanger, have shown many advantages compared to the conventional gasifiers (Hofbauer & Materazzi, 2019). The mix-up of product gas and flue gas is avoided in this type of gasification. Secondly, while using air for biomass combustion, the nitrogen present in air reduces the quality of the end product by not participating in gasification, thus resulting in a diluted product gas. A high-quality product gas can be obtained from allothermal gasifiers without the need for establishing an expensive air separation unit, as required in case of conventional gasifiers. The 50 kWth Indirectly Heated Bubbling Fluidized Bed Steam Reformer (IHBFBSR) at Delft University of Technology (TU Delft) represents a new concept of allothermal gasification technology where heat required for the endothermic gasification reactions is provided by two radiant tube burners placed vertically inside the reactor, one at the top and one at the bottom. The aim of this research is to optimize and validate the kinetic model developed for the IHBFBSR by a former student, Maarten Kwakkenbos in Aspen Plus®. The optimization is carried out with the help of the several steps, described in the report. The optimized model is then validated by using the results of the gasification tests performed under various operational conditions by PhD Candidates Mara del Grosso and Christos Tsekos. The optimized model predicts the gas composition obtained from the IHBFBSR quite well. In addition to the yield of permanent gases, N2, H2O and tars concentration in the product gas, along with various gas ratios (CO/H2, CH4/H2, CO/CO2) from the model are compared with the experimental values and found to be in reasonable agreement. Moreover, key performance indicators such as carbon conversion (CC), cold gas efficiency (CGE) and overall efficiency (OE) are also evaluated from both model and experiments and compared. The error ranges for most of the parameters lie within the reported deviations observed in various gasifier models in literature. After the validation of the model, the possibility of recycling a fraction of the product gas to feed the burners in order to make the set up more sustainable is evaluated. Sensitivity analyses is performed by varying steam to biomass ratios (SB*), primary and secondary air flowrate to evaluate the best process conditions under which product gas obtained from the gasifier, after subsequent cleaning, can be used for methanol production based on the H2/CO ratio. The results indicate that a higher SB* and a higher secondary air flowrate can result in a H2/CO ratio closer to the desired value required for optimum methanol production. From the heat analysis performed for the model, a possibility of increasing the overall efficiency of the process by adding a bypass line in the gasifier setup is suggested to be explored. The master thesis concludes by answering the research questions and recommendations to improve the detailing and accuracy of the model.Electrical Engineering | Sustainable Energy Technolog
Fortification of Fruit and Cereal Bars.
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Treatability study of the effluent containing reactive blue 21 dye by ozonation and the mass transfer study of ozone
No full text
Enhancing database schema with rules generated from knowledge discovery tools
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
make a request on their behalf. Monash staff and postgraduate students can use the link in the References field
Strengthening Civil Society: Lessons from the Consumer Forum at Basrur in Karnataka
No full textNecessitated by the inherent limitations of the market and failures in governance by the State, the search for alternative solutions has witnessed the emergence of the sphere of civil society. Organisations of ordinary people have taken up the task of ensuring better governance through their interactions with both the state and the market. The Consumer Forum at Basrur is a civil society organisation that seeks to build capacities amongst citiZens and empower them to demand greater accountability from both the government and private players. Its key tool is effective communication, particularly through letter-writing, wherein the Forum guides the consumers in establishing contact with suppliers and officials and finding solutions to their problems in a cost effective and transparent manner. In this paper, the author studies the methodology and work of this Forum in order to assess the possibility of replicating the model
