Bubbly Turbulent Drag Reduction Is a Boundary Layer Effect

In turbulent Taylor-Couette flow, the injection of bubbles reduces the overall drag. On the other hand, rough walls enhance the overall drag. In this work, we inject bubbles into turbulent Taylor-Couette flow with rough walls (with a Reynolds number up to 4×105), finding an enhancement of the dimensionless drag as compared to the case without bubbles. The dimensional drag is unchanged. As in the rough-wall case no smooth boundary layers can develop, the results demonstrate that bubbly drag reduction is a pure boundary layer effec

Predicting harmonic distortion of multiple converters in a power system

Various uncertainties arise in the operation and management of power systems containing Renewable Energy Sources (RES) that affect the systems power quality. These uncertainties may arise due to system parameter changes or design parameter choice. In this work, the impact of uncertainties on the prediction of harmonics in a power system containing multiple Voltage Source Converters (VSCs) is investigated. The study focuses on the prediction of harmonic distortion level in multiple VSCs when some system or design parameters are only known within certain constraints. The Univariate Dimension Reduction (UDR) method was utilized in this study as an efficient predictive tool for the level of harmonic distortion of the VSCs measured at the Point of Common Coupling (PCC) to the grid. Two case studies were considered and the UDR technique was also experimentally validated. The obtained results were compared with that of the Monte Carlo Simulation (MCS) results

Topics in algebraic geometry

The dissertation begins in Chapter I with the basic properties of an algebral variety. The Hilbort Nulletellenesiz and its important consequenses are than given; the proofs of the results on dimension are greatly simplified by appealing to a result of the next chepter. In chapter II, the longth of a primary ideal is first discussed, preparatory to the ideas of height and depth of prime ideals. The fundamental equivalence between height and depth, and rans and dimension in a finite integral domain, is the last main theorem of this chapter. The simple point on a varlety is discussed in Chapter III form a local-algebraic point of view. It is shown that simplicity corresponds to regularity of the local ring, as defined by W. Krull. Finally the Jacobisn Oriterion for a simple point of a variety is established, and we montion the extension to algebraic subvarieties

Studies on genetic uniformity of Chowghat Green Dwarf and Malayan Green Dwarf varieties of coconut using molecular and morphometric methods

Two coconut varieties viz., Chowghat Green Dwarf (CGD) and Malayan Green Dwarf (MGD) were subjected to morphometric and molecular studies to assess their genetic uniformity. Since both these varieties possess traits for high yield and resistance to root (wilt) disease, they have already been released for cultivation in the root (wilt) disease prevalent tracts. Forty two CGD palms from ‘disease hotspots’ were analyzed using 43 simple sequence repeat (SSR) primers. Monomorphic bands were detected in all the CGD samples with 41 primers, which is an indication of its genetic uniformity. A single CGD palm showed polymorphism with two SSR primers. Forty eight MGD palms were analyzed using 24 SSR primers. The MGD palms clustered at 62 per cent similarity. Analysis of morphological and fruit component characters of CGD and MGD population revealed that both the populations were phenotypically uniform. Breeding behaviour studies revealed that both CGD and MGD were predominantly self pollinated, like other dwarf varieties of coconut. There was complete overlapping of male and female phases in almost 96 per cent of CGD palms. Almost 100 per cent self-pollination was ensured in these palms as male phase prolonged even after completion of female phase. However, only 60 per cent of the MGD palms showed complete overlapping and in the remaining 40 per cent palms, there was only partial overlapping of male and female phases. From the present study, it is inferred that breeding behavior and genetic uniformity could be highly correlated in coconut. Collection of seed nuts preferably from mother palms with overlapping of male and female phases could possibly ensure production of true to type progenies in dwarf varieties of coconut. Present study also indicated that molecular markers like SSRs may be used to identify genetically pure mother palms for varietal improvement programmes in coconut

Application of PCR to a clinical and environmental investigation of a case of equine botulism

PCR for the detection of botulinum neurotoxin gene types A to E was used in the investigation of a case of equine botulism. Samples from a foal diagnosed with toxicoinfectious botulism in 1985 were reanalyzed by PCR and the mouse bioassay in conjunction with an environmental survey. Neurotoxin B was detected by mouse bioassay in culture enrichments of serum, spleen, feces, and intestinal contents. PCR results compared well with mouse bioassay results, detecting type B neurotoxin genes in these samples and also in a liver sample. Other neurotoxin types were not detected by either test. Clostridium botulinum type B was shown to be prevalent in soils collected from the area in which the foal was raised. Four methods were used to test for the presence of botulinum neurotoxin-producing organisms in 66 soil samples taken within a 5-km radius: PCR and agarose gel electrophoresis (types A to E), PCR and an enzyme-linked assay (type B), hybridization of crude alkaline cell lysates with a type B-specific probe, and the mouse bioassay (all types). Fewer soil samples were positive for C. botulinum type B by the mouse bioassay (15%) than by any of the DNA-based detection systems. Hybridization of a type B-specific probe to DNA dot blots (26% of the samples were positive) and PCR-enzyme-linked assay (77% of the samples were positive) were used for the rapid analysis of large numbers of samples, with sensitivity limits of 3 x 10(6) and 3,000 cells, respectively. Conventional detection of PCR products by gel electrophoresis was the most sensitive method (300-cell limit), and in the present environmental survey, neurotoxin B genes only were detected in 94% of the samples

Studies on infectious etiologies associated with neurological disorders in pigeons in Kerala

Pigeons are reared as a symbol of peace, love, gentleness and spirit messengers and now-a-days also for meat, as ornamental pet bird or as an experimental animal. There are about 400 varieties of fancy pigeons and little is known about the diseases and management of these birds. Heavy mortality has been observed in the pigeons that shows neurological manifestations. The present study is aimed at diagnosis of infectious diseases causing neurological signs in pigeons. The study was conducted in the different pigeon lofts of four districts in Kerala and a total of 44 pigeons comprising 21 fancy breeds were included. These birds were screened for major infectious etiologies causing neurological signs like paramyxoviral infection, salmonellosis and Haemoproteus infection. The birds were also screened for presence of ectoparasites by visual examination. The study showed 63.63 per cent positive for paramyxoviral infection using antigen NDV kits. The occurrence of Haemoproteus infection was 54.7 per cent in Giemsa-stained blood smears and 63.63 per cent in PCR amplifying cyt b gene. Pseudolynchia canariensis could be detected in pigeons. Isolation and identification of Salmonella from faecal samples were done by culture and biochemical tests and found to be 22.2 per cent. Combined infections of paramyxovirus infection with Haemoproteus, paramyxovirus infection with Salmonella, Haemoproteus with Salmonella and infection of all the three etiologies were the interesting finding of the study. The present study is one of its kind in Kerala and also in India. The study warrants the prevention and control of these infectious diseases which has great zoonotic potential