Browsing by Author "Agarwal, Gaurav"
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- Pseudomonas coronafaciens sp. nov., a new phytobacterial species diverse from Pseudomonas syringaeDutta, Bhabesh; Gitaitis, Ronald; Agarwal, Gaurav; Coutinho, Teresa; Langston, David B. (PLOS, 2018-12-06)We propose Pseudomonas coronafaciens sp. nov. as a new species in genus Pseudomonas, which is diverse from P. syringae. We also classified strains from onions which are responsible for yellow bud (YB) disease as P. coronafaciens. Sequencing of 16S rRNA gene and multi-locus sequence analysis (MLSA) of housekeeping genes (gyrB, rpoD, gltA and gap1 genes) for the P. syringae pv. coronafaciens strains along with other strains of P. syringae pathovars resulted in a distinct cluster separate from other P. syringae pathovars. Based on DNA-DNA relatedness, pathotype strain of P. syringae pv. coronafaciens (CFBP 2216(PT)) exhibited <= 35.5% similarity with the pathotype strains of P. syringae pv. syringae (CFBP 1392(PT), 4702(T)) but exhibited >= 90.6% with the YB strains (YB 12-1, YB 12-4, YB 09-1). Also, the YB strains (YB 12-1, YB 12-4, YB 09-1) were able to infect only onion but not oat, rye and Italian ryegrass (common hosts for P. syrinage pv. coronafaciens). Contrastingly, P. syringae pv. coronafaciens strains (NCPPB 600(PT), ATCC 19608, Pcf 83-300) produced typical halo blight symptoms on oat, rye and Italian rye grass but did not produce any symptoms on onion. These results provide evidence that P. syringae pv. coronafaciens should be elevated to a species level and the new YB strains may potentially be a novel pathovar of hereto proposed P. coronafaciens species.
- Solid Fuel Blend Pyrolysis-Combustion Behavior and Fluidized Bed HydrodynamicsAgarwal, Gaurav (Virginia Tech, 2013-10-16)As a carbon neutral and renewable source of energy, biomass carries a high potential to help sustain the future energy demand. The co-firing of coal and biomass mixtures is an alternative fuel route for the existing coal based reactors. The main challenges associated with co-firing involves proper understanding of the co-firing behavior of blended coal-biomass fuels, and proper understanding of advanced gasification systems used for converting such blended fuels to energy. The pyrolysis and combustion behavior of coal-biomass mixtures was quantified by devising laboratory experiments and mathematical models. The pyrolysis-combustion behavior of blended fuels was quantified on the basis of their physicochemical, kinetic, energetic and evolved gas behavior during pyrolysis/combustion. The energetic behavior of fuels was quantified by applying mathematical models onto the experimental data to obtain heat of pyrolysis and heat of combustion. Fuel performance models were developed to compare the pyrolysis and combustion performance of non-blended and blended fuels. The effect of blended fuel briquetting was also analyzed to find solutions related to coal and biomass co-firing by developing a bench scale fuel combustion setup. The collected data was analyzed to identify the effects of fuel blending and briquetting on fuel combustion performance, ignitability, flammability and evolved pollutant gases. A further effort was made in this research to develop the understanding of fluidized bed hydrodynamics. A lab scale cold-flow fluidized bed setup was developed and novel non-intrusive techniques were applied to quantify the hydrodynamics behavior. Particle Image Velocimetry and Digital Image Analysis algorithms were used to investigate the evolution of multiple inlet gas jets located at its distributor base. Results were used to develop a comprehensive grid-zone phenomenological model and determine hydrodynamics parameters such as jet particle entrainment velocities and void fraction among others. The results were further used to study the effect of fluidization velocity, particle diameter, particle density, distributor orifice diameter and orifice pitch on the solid circulation in fluidized beds.