Numerical Investigation for Combustion Characteristics of Vacuum Residue in a Test Furnace

S. Sreedhara,Kang Y. Huh,Hoyoung Park 한국연소학회 2006 KOSCOSYMPOSIUM논문집 Vol.- No.-

It has become inevitable to search for alternative fuels due to severe energy crisis these days. Use of alternative fuels, which are typically of lower quality, tends to increase environmental pollution, including formation of nitrogen oxides (NOx). In this paper performance of vacuum residue has been investigated experimentally as well as numerically in typical operating conditions of a furnace. Heat release reaction is modeled as sequential steps of devolatilization, simplified gas phase reaction and char oxidation as that for pulverized coal. Thermal and fuel NOx are predicted by conditional estimation of elementary reaction rates and are compared against measured experimental data. On the overall reasonable agreement is achieved for spatial distributions of major species, temperature and NOx for all test cases.

Modeling of Turbulent, Two-Dimensional Nonpremixed CH₄/H₂ Flame over a Bluff-body using First-and Second-order Elliptic Conditional Moment Closure

S. Sreedhara,Kang Y. Huh 한국연소학회 2005 KOSCOSYMPOSIUM논문집 Vol.- No.-

Relationship between Mating Success and Wing Length in a Drosophilid: Phorticella striata

Sarat Chandra Yenisetti,Sreedhara Narayana Hegde,Mididoddi Venkateswarlu 한국유전학회 2008 Genes & Genomics Vol.30 No.1

Correlative studies were made between mating success and wing length in a drosophilid insect Phorticella striata. Mating latency (time elapsed until mating from introduction) noted for all the matings. Observations were made for one hour considering number of pairs mated in every 15 minutes as one group. Mating latency of the flies gradually increased from 0-15 min to 45-60 min. Data showed that difference in mean number of flies mated during different time intervals was significant, but the difference was non-significant between age groups, suggesting age has no influence on mating latency. Males mating in the first fifteen minutes (0-15 min) time interval had significantly longer wings. In females also there was significant difference in wing length that mate in different time intervals. Females mating in the first thirty minutes (0-30 min) bear significantly longer wings when compared with those that mate during 31-60 min. This showed large flies mate early in both the sexes. Thus the present study shows a direct relationship between wing length and mating success. So there is sexual selection acting on body size.

Phenotypic Plasticity of Sexual Behavior at Different Temperatures in a Drosophilid: Phorticella striata

Sarat Chandra Yenisetti,Sreedhara Narayana Hegde,Mididoddi Venkateswarlu,Mysoru Siddaiah Krishna 한국유전학회 2006 Genes & Genomics Vol.28 No.4

Phenotypic plasticity is the capability of a genotype to produce different phenotypes in different environments. The effects of changes in ambient temperature on reproductive fitness traits such as mating latency, copulation duration and mating success were studied in the Mysore and Ahmedabad populations of Phorticella striata at four ambient temperatures: - 15℃, 22℃, 29℃ and 36℃. Between the two populations the difference in mating latency was insignificant. However, the difference in copulation duration was significant between the two strains. The differences in mating latency and copulation duration at the four temperatures were also significant. Both populations exhibited long mating latency and short copulation duration at 15℃ and short mating latency, long copulation duration at 22℃ and 29℃. At 36℃ flies did not mate at all. The greatest mating success (%) was observed at 22℃ in both the Mysore and Ahmedabad populations. At 15℃, and 29℃ mating success was low. Chi-square test showed that the difference in mating success between the two populations was insignificant at different temperatures. Mating latency, copulation duration and mating success are independent events in the sexual process. These traits need not be expressed similarly by the same species under different situations. Thus, the present study heralds the phenotypic plasticity of sexual behavioral traits under various ambient temperatures. Our findings strengthen the support for the adaptive nature of temperature - mediated plasticity in sexual behavior.

EXHAUST EMISSIONS AND ITS CONTROL METHODS IN COMPRESSION IGNITION ENGINES: A REVIEW

P. BRIJESH,S. SREEDHARA 한국자동차공학회 2013 International journal of automotive technology Vol.14 No.2

Extensive usage of automobiles has certain disadvantages and one of them is its negative effect on environment. Carbon dioxide (CO2), carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx), sulphur dioxide (SO2) and particulate matter (PM) come out as harmful products during incomplete combustion from internal combustion (IC)engines. As these substances affect human health, regulatory bodies impose increasingly stringent restrictions on the level of emissions coming out from IC engines. This trend suggests the urgent need for the investigation of all aspects relevant to emissions. It is required to modify existing engine technologies and to develop a better after-treatment system to achieve the upcoming emission norms. Diesel engines are generally preferred over gasoline engines due to their undisputed benefit of fuel economy and higher torque output. However, diesel engines produce higher emissions, particularly NOx and PM. Aftertreatment systems are costly and occupy more space, hence, in-cylinder solutions are preferred in reducing emissions. Exhaust gas recirculation (EGR) technology has been utilized previously to reduce NOx. Though it is quite successful for small engines, problem persists with large bore engines and with high rate of EGR. EGR helps in reducing NOx, but increases particulate emissions and fuel consumption. Many in-cylinder solutions such as lower compression ratios, modified injection characteristics, improved air intake system etc. are required along with EGR to accomplish the future emission norms. Modern combustion techniques such as low temperature combustion (LTC), homogeneous charge compression ignition (HCCI),premixed charge compression ignition (PCCI) etc. would be helpful for reducing the exhaust emissions and improving the engine performance. However, controlling of autoignition timing and achieving wider operating range are the major challenges with these techniques. A comprehensive review of diesel engine performance and emission characteristics is given in this paper.

Influence of Substrate Temperature on the Electrical, Morphological and Structural Properties of Electron Beam Evaporated LBMO Thin Films

Chundi Seshendra Reddy,A. Sivasankar Reddy,P. Sreedhara Reddy 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

La0.7Ba0.3MnO3 (LBMO) thin films were deposited on Si substrates at various substrate temperatures (Ts) ranging from 823 K to 1023 K using electron beam evaporation (EBE), and studied the structural, composition and electrical properties of the films as a function of deposition temperature were studied. X-ray diffraction (XRD) studies revealed the epitaxial growth in the films. The surface morphology of the films were characterized by atomic force microscopy (AFM). The elemental composition analysis investigated by energy dispersive spectroscopy (EDS) confirmed the stoichiometry. The films deposited at higher substrate temperatures (1023 K), showed lower resistivity with a higher temperature coefficient of resistance (TCR). A TCR of 4.09%/K obtained in the present investigation is suitable for bolometric applications near to the room temperature.

The Genetic Relatedness Analysis of Male Sterile and Their Maintainer Lines of Onion (Allium cepa L.) by Using RAPD Primers

Lakshmana Reddy Dhoranalapalli,Dhanya shivnanajappa,Verre Gowda,Sreedhara Sindughatta Antharamiah,Aswath Chennareddy 한국작물학회 2013 Journal of crop science and biotechnology Vol.16 No.1

RAPD markers analysis was performed to investigate genetic relatedness among nine sterile (A), maintainer lines (B), and male parents (C) of onion. Initially, 180 arbitrary decamer primers were screened; of these 20 primers were selected which yielded 812bands, 45.34% of which were found to be polymorphic. Squared-Euclidean Distance matrix revealed a minimum genetic distance between the genotypes MS 48A and MF 65C and a maximum genetic distance between the genotypes MLT 84C and MF 65B. Cluster analysis grouped the nine onion genotypes into two major clusters. The first cluster consisted of two male sterile groups, i.e. MS-65 (Arka Lalima) and MS-48 (Arka Kirthiman) of single bulb onions. The second cluster consists of MLT (Multiplier) group. PCA re-confirmed the results of the dendrogram, revealing the precision in estimation of genetic relatedness among the genotypes tested. None of the primers produced unique banding patterns to distinguish all nine genotypes. This information about genetic relatedness among the nine genotypes would be better utilized in further onion breeding programs

Effect of Substrate Temperature on Structural, Optical and Electrical Properties of Sputtered NiO-Ag Nanocrystalline Thin Films

Y. Ashok Kumar Reddy,B. Ajitha,P. Sreedhara Reddy,프라탑 렙디,이정희 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.5

NiO-Ag thin films were deposited on Corning 7059 glass substrates by DC reactive magnetron sputtering technique and investigated the substrate temperature (Ts) dependent properties of NiO-Ag thin films. X-ray diffraction results showed that crystalline films can be obtained at high Ts and all films have a preferred crystal growth texture with face centered cubic (fcc) structure and was also confirmed by Raman studies. The grain size, transmittance, band gap, mobility and carrier concentrations were increased with Ts. Room temperature deposited films have an average roughness around 6.9 nm where as increment of Ts resulted in increased roughness up to 14 nm with nanocrystalline morphology. The optimum substrate temperature to obtain NiO-Ag films was found to be 200°C. It was found that with increasing the Ts, resistivity of the films was significantly decreased.

CMC 모델 기반 수치해석을 사용한 순산소 난류확산화염 구조 연구

김종수(Jong Soo Kim),S. Sreedhara,허강열(Kang Yeol Huh),양원(Won Yang) 한국연소학회 2008 한국연소학회지 Vol.13 No.1

Oxy-fuel flame has a significantly different structure from that of air-fuel flame because of its high temperature. This study is aimed to find out the difference of the oxy-fuel flame structure in order to understand reaction mechanism closely, which is crucial to design real-scale oxy-fuel combustion system. By examining pictures of counterflow flame and LIF images, we found that oxy-fuel flame had two-zone structure: fuel decomposition region and distributed CO oxidation region. In the oxy-fuel flame, OH radical was distributed intensely through the whole flame due to its higher flame temperature than crossover temperature. For showing those features of the oxy-fuel flame, 1 MW scale IFRF oxy-natural gas burner was simulated by conditional moment closure(CMC) model. Calculation results were compared with experimental data, and showed agreements in trend. In the simulated distributions of fuel decomposition/CO oxidation rates, CO oxidation region was also separated from fuel decomposition zone considerably, which showed the two-zone structure in the oxy-fuel flame.

The Genetic Relatedness Analysis of Male Sterile and Their Maintainer Lines of Onion (Allium cepa L.) by Using RAPD Primers

Shivnanajappa, Dhanya,Chinnappareddy, Lakshmana Reddy Dhoranalapalli,Gowda, Verre,Antharamiah, Sreedhara Sindughatta,Chennareddy, Aswath 한국작물학회 2013 Journal of crop science and biotechnology Vol.16 No.1

RAPD markers analysis was performed to investigate genetic relatedness among nine sterile (A), maintainer lines (B), and male parents (C) of onion. Initially, 180 arbitrary decamer primers were screened; of these 20 primers were selected which yielded 812 bands, 45.34% of which were found to be polymorphic. Squared-Euclidean Distance matrix revealed a minimum genetic distance between the genotypes MS 48A and MF 65C and a maximum genetic distance between the genotypes MLT 84C and MF 65B. Cluster analysis grouped the nine onion genotypes into two major clusters. The first cluster consisted of two male sterile groups, i.e. MS-65 (Arka Lalima) and MS-48 (Arka Kirthiman) of single bulb onions. The second cluster consists of MLT (Multiplier) group. PCA re-confirmed the results of the dendrogram, revealing the precision in estimation of genetic relatedness among the genotypes tested. None of the primers produced unique banding patterns to distinguish all nine genotypes. This information about genetic relatedness among the nine genotypes would be better utilized in further onion breeding programs.