Validation of radiant and convective heat transfer models of photonic membrane using non-invasive imaging of condensation pattern

Cooling a sample of a material until condensation is observed is a standard technique for accurately measuring the dewpoint and associated relative humidity in a volume. When conducting an experiment with a membrane-assisted radiant cooling panel, we found that membrane surface temperatures were difficult to measure directly. Instead, the onset of condensation was used to infer the membrane’s surface temperature. However, the radiant cooling panels displayed variations of membrane surface temperature at steady state, and thus a resulting condensation contour was observed, forming a curve on which the membrane surface temperature was accurately known and constant - the dewpoint. The curve was in equilibrium between the internal panel temperature driven by internal free convection in the air gap and the view factor to surrounding surfaces, which can be evaluated at each point along the curve. In this paper, we assess the convective and radiative heat transfer balances using simulations. Our methods expand the “sensing” of condensation to provide information about view factor and thermal stratification, both of which are quantities that are difficult to measure adequately in the field.

Thin layer immunoassay; an economical approach to diagnose Helicobacter pylori Infection in gastroduodenal ulcer disease patients of Pakistan; a comparative analysis

Helicobacter pylori is a causative agent of gastritis, gastroduodenal ulcers and gastric adenocarcinoma. Gastric patient’s serums were screened for H. pylori infection by thin layer immunoassay. A polystyrene plate coated with H. pylori sonicate whole cell antigen (10 μg/ml). Two fold-diluted patient’s serum was allowed to react at 37 °C, incubated at 60 °C for 1 min over water bath and recorded water condensation pattern for H. pylori antibody. Gastric patient’s blood samples (62% male and 6% female) were tested positive for H. pylori, while agewise 15–25 years males (36%) and 65–75 years females (50%) showed highest number of H. pylori infection. Thin layer immunoassay showed sensitivity (72–67%), specificity (100%), accuracy (94–69%) and κ value (0.493–0.357) in comparison with wELISA, sELISA and kELISA. We conclude thin layer immunoassay was reliable, low cost, quick, simple and clinically useful method for H. pylori diagnosis in patients of Pakistan.

The platinum-rich scandium silicide Sc2Pt9Si3

Single crystals of Sc2Pt9Si3 have been obtained from an arc-melted and inductively annealed sample of the starting composition Sc:4Pt:2Si. The Sc2Pt9Si3 structure (Tb2Pt9Ge3 type, space group C2/c) was refined from single crystal X-ray diffractometer data: a=1303.4(1), b=749.9(1), c=973.5(1), β=116.44(1)°, wR2=0.0731, 1643 F2 values and 67 variables. The structure contains three basic coordination polyhedra Sc@Pt11, Si1@Pt8 and Si2@Pt8 which show a simple condensation pattern avoiding direct Sc–Si and Si–Si bonding.

Effect of Thin Metal Film and Micro Structure of Surface on Condensation Pattern

The water condensation is important for wide range of industrial systems such as condensers and heat exchangers of steam power plants and refrigerators. The condensation generally has two patterns; filmwise condensation (FWC) and drop-wise condensation (DWC). DWC has one-tenth higher heat transfer coefficient than that of FWC. It has been pointed out by many investigators that DWC occurs on the hydrophobic surface and FWC occurs on hydrophilic surface. However, the durability of those hydrophobic effects was not clear enough. In order to maintain a sufficiently long DWC, it is important to understand the effect of the surface property and structure on the condensation surface in more detail. The recent advancement of MEMS (Micro Electro Mechanical System) technology enables us to change the physical nature the surface in the micro scale. It is expected that the hydrophobic surface by the MEMS technology may kept DWC for a longer time. In the present paper, we experimentally investigate the effects of thin metal film and micro structured surface on condensation pattern. Especially, our condensation experiments were performed with the micro structured surfaces by using etching and the metal thin film surfaces by sputtering for approximately 24 hours. Silicon (Si) wafer was used as a basic surface. For the metal thin films surface, we used sputtered Lead (Pb) and Titanium (Ti) on Si surface. For the micro structured surfaces, micro-structured grid was etched on Si surface with several conditions. In order to obtain the relation between the condensation pattern and surface condition, the surface conditions were measured by laser micro-scope, contact angle meter and atomic force microscope (AFM). For the metal thin films surface, condensation patterns on thin Pb film surface showed DWC. Meanwhile, condensation patterns on thin Ti surfaces showed FWC. From our results, the adsorption forces decreased with increasing contact angle on DWC for Pb. On the other hand, the adsorption forces increased with decreasing contact angle on FWC for Ti. For the micro structured surfaces, condensation pattern was FWC and contact angle decreased in our experimental results. This is because that the condensed water is accumulated in the groove on the micro structure surface.

Comparative description and discussion of spermiogenesis and spermatozoal ultrastructure in some species of Heptapteridae and Pseudopimelodidae (Teleostei: Siluriformes)

The data obtained in the present study on spermiogenesis and spermatozoal ultrastructure of Pseudopimelodidae and Heptapteridae show that they share some characteristics, but greatly differ from each other. The main differences are the occurrence of type I spermiogenesis in Pseudopimelodidae and type III in Heptapteridae, the presence of nuclear fossa in Pseudopimelodidae and its absence in Heptapteridae, the presence of long midpiece in Pseudopimelodidae and short midpiece in Heptapteridae, the presence of cytoplasmic canal in Pseudopimelodidae and its absence in Heptapteridae, the presence of many large vesicles in the midpiece of Pseudopimelodidae and the presence of very long vesicles placed in the peripheral distal region in Heptapteridae, and mitochondria distributed all over the midpiece in Pseudopimelodidae, and very close to the nucleus in Heptapteridae. Heptapteridae and Pimelodidae share several characteristics, such as type III spermiogenesis, a similar chromatin condensation pattern, and the absence of nuclear fossa and flagellar lateral fins. The spermatozoa of Pseudopimelodidae is more similar to those of Siluridae. However, the absence of additional data on spermiogenesis and spermatozoa in siluriforms still limits a broader discussion in the order.

NEW CHROMOSOME COUNTS AND NUCLEAR CHARACTERISTICS FOR SOME MEMBERS OF GESNERIACEAE SUBFAMILY CYRTANDROIDEAE FROM CHINA AND VIETNAM

The morphological characteristics of mitotic interphase, prophase and metaphase nuclei were analysed for 21 taxa in 14 genera from three different tribes of subfamily Cyrtandroideae (Gesneriaceae) from Asia. Interphase nuclei were classified into three categories: (1) complex chromocentres, as in Ancylostemon, Briggsia, Briggsiopsis, Chirita, Loxostigma, Lysionotus, Oreocharis, Petrocosmea, Raphiocarpus and Whytockia, (2) simple chromocentres, as in Paraboea and Rhabdothamnopsis, and (3) round prochromosomes, as in Anna and Didymocarpus. Species with complex chromocentres seem to be most common among all three tribes. The data further indicate that tribe Didymocarpeae is cytologically much more heterogeneous than other tribes, which accords with the diversity in morphological characters. Three types of chromosome condensation pattern during mitotic prophase were observed, here described as interstitial, gradient and proximal. Except for Ancylostemon, exhibiting a proximal type, and Lysionotus and Whytockia possessing a gradient type, all other species analysed to date exhibit the interstitial type. Our study also reports the chromosome numbers of 12 species in 10 genera of subfamily Cyrtandroideae from China and Vietnam; 11 of these counts are new.

Artificial Transformation of the Direct-Contact Condensation Pattern of Steam Bubbles in a Hydrophobic Liquid Medium

When steam bubbles are released into a medium of a hydrophobic coolant, the condensate is scattered through the coolant in the form of tiny droplets. This condensation pattern is unfavorable for direct-contact condensers because it is difficult to separate the condensate and the coolant. This paper proposes a novel bubble-release device by which the condensation pattern is so transformed that the condensate remains within the confines of the bubble wall. An experimental examination with single steam bubbles released into a medium of liquid paraffin is demonstrated.