Unravelling mucosal immunity to poliovirus

Comment - No abstrac

Experimental investigation of two-phase pressure drop in a microchannel

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.An experimental study of two-phase pressure drop in a horizontal circular microchannel is presented in this paper. Test tube is made of fused silica having an internal diameter of 781μm with a total length of 261mm and a heated length of 191mm.The external surface of the test tube is coated with an electrically conductive thin layer of ITO (Indium Tin Oxide) for direct heating of test section. Refrigerant R134a was used as the working fluid and mass flux during the experiments was varied from 100 to 650 kg/m2sec. Experiments were performed at a system pressure of 7.70 bar (corresponding to saturation temperature of 30oC). Two-phase frictional pressure drop characteristics with different mass flux, vapour fraction and heat flux were explored in detail. Finally, the prediction capability of well known available correlations in the literature, developed for macrochannels and others especially developed for microchannels was also checked. The homogeneous model predicts the data fairly well with a mean absolute deviation (MAD) of 19% and 69% of data within ±20% error band. The Müller-Steinhagen and Heck (1986) correlation developed for macrochannels predicts the data with a MAD of 19% and 61% of data within ±20% error band. The Mishima and Hibiki (1996) correlation, developed for microchannels, also shows fairly good approximation of the data with MAD of 19% and 57% of data within ±20% error band

Design for Microchannel Condensers with Separation Circuiting

It has been proved both experimentally and by modeling that separation of vapor and liquid is beneficial for performance of a condenser prototype with a specific separation circuiting. The prototype has an inlet in the middle of the height and separates into two flow paths after the second header. The two paths recombine upstream the exit of the condenser. This paper presents a search for optimal design for condensers with separation circuiting based on an experimentally validated steady-state condenser model. That model incorporates a mechanistic model of a flow in header to consider phase separation efficiency. Parametric studies are performed on pass circuitry, fin density and air velocity distribution. The trade-off between high heat transfer and high pressure drop for flow in the vapor path is further explained. After a design optimization, the condenser with separation circuiting shows potential for approximately 10% performance improvement compared to the baseline condenser with the same total air-side area

Experimental investigation of condensation heat transfer in microchannels.

PhDThe thesis describes experiments aimed at measurement of heat-transfer coefficients for condensation in a multi micro channel tube. Experiments were performed with steam and R113, fluids chosen to cover a wide range of thermophysical properties, in particular, surface tension which plays an important role during condensation in small, non-circular channels. The aluminum extruded condenser tube used had cooled length 748 mm and 13 parallel channels each with height 1.38 mm and width 1.41 mm. The upper and lower outer surfaces were cooled separately by water in counter flow in channels above and below the test tube. The mass flow rates in the two channels were adjusted to be the same. Coolant temperatures were measured at 17 positions along each of the coolant channels as well as at inlet and exit. An accurate direct measurement of the overall inlet-to-outlet coolant temperature difference was also measured directly with a 10 junction thermopile for each of the two coolant streams with junctions downstream of mixers. Temperatures of the condenser tube wall were measured at 10 positions on each of the upper and lower surfaces using embedded thermocouples. Temperatures and pressures of the vapour were measured in chambers at the inlet and outlet of vapour stream. Pressures were also measured in the condenser channels just upstream and just downstream of the cooled section. Data have been obtained for cases where the vapour was saturated (for both steam and R113) at inlet. Runs were made for complete and incomplete condensation within the tube. Earlier investigations are critically reviewed and seen to exhibit wide scatter and disagreement. For reasons which will become clear in the thesis, the present results cannot, unfortunately, be claimed to have superior accuracy and generally fall within the ranges of earlier data. A new and innovative test section has been designed and will be used in forthcoming experiments

The Genetic Studies of Obsessive-Compulsive Disorder and Its Future Directions

Obsessive-compulsive disorder (OCD) is characterized by recurrent and persistent thoughts (obsessions), and repetitive behaviors or mental acts (compulsions). In Korea, an epidemiological study reported that the lifetime prevalence of OCD in the population was greater than two percent. The exact cause of OCD is still unknown. Evidence from familial, twin and segregation studies supports the role of a genetic component in the etiology of OCD. In addition, there is growing evidence that OCD has a specific neurochemical and neuroanatomical basis. According to this evidence, researchers have selected various candidate genes which have been implicated in the neurophysiology of OCD, and differences of allelic variants in OCD patients and controls have been analyzed. In this review we will introduce the results of previous genetic studies of OCD which have been performed in other populations, including twin studies, family studies, segregation analyses, linkage analyses, and association studies. In addition to these studies, we will present the results of our genetic studies of OCD performed in Korea

Separation of Liquid and Vapor in Header of MCHE

This paper presents the experimental study of separation of two-phase flow in a vertical header of microchannel heat exchanger (MCHE) based on quantified visualization using fast camera, modelling analysis and experimental evaluation. A condenser model is developed to explore separation effects on heat exchanger. The modeling results show the benefits that a separation condenser has over a conventional condenser is affected by the separation results in the header. A header prototype is made that has an inlet in the longitudinal center part. Two sub-passes downstream are incorporated, lower for liquid and upper vapor flow. The header for experiment is clear to provide visual access. R-134a is used as the fluid of interest and mass flux through the inlet microchannels is controlled between 55 kg/(m2s)-195 kg/(m2s). The experiment results indicate that ideal separation in that header can happen at low mass flux up to 70 kg/(m2s). Results are presented in function of liquid and vapor separation efficiencies (ηl, ηv). Two phase flow inside the header is analyzed to study the mechanisms for liquid-vapor separation.

Comparative genome-wide analysis of repetitive DNA in the genus Populus L.

Genome skimming was performed, using Illumina sequence reads, in order to obtain a detailed comparative picture of the repetitive component of the genome of Populus species. Read sets of seven Populus and two Salix species (as outgroups) were subjected to clustering using RepeatExplorer (Novák et al. BMC Bioinformatics 11:378 2010). The repetitive portion of the genome ranged from 33.8 in Populus nigra to 46.5% in Populus tremuloides. The large majority of repetitive sequences were long terminal repeat-retrotransposons. Gypsy elements were over-represented compared to Copia ones, with a mean ratio Gypsy to Copia of 6.7:1. Satellite DNAs showed a mean genome proportion of 2.2%. DNA transposons and ribosomal DNA showed genome proportions of 1.8 and 1.9%, respectively. The other repeat types accounted for less of 1% each. Long terminal repeat-retrotransposons were further characterized, identifying the lineage to which they belong and studying the proliferation times of each lineage in the different species. The most abundant lineage was Athila, which showed large differences among species. Concerning Copia lineages, similar transpositional profiles were observed among all the analysed species; by contrast, differences in transpositional peaks of Gypsy lineages were found. The genome proportions of repeats were compared in the seven species, and a phylogenetic tree was built, showing species separation according to the botanical section to which the species belongs, although significant differences could be found within sections, possibly related to the different geographical origin of the species. Overall, the data indicate that the repetitive component of the genome in the poplar genus is still rapidly evolving