Insufficiently effective operation of inlet tubes in the coolant flow direction during steam condensation in parallel channels with nonuniform heat removal (e.g., in air-cooled steam condensers) has been recognized. It has been revealed by the calculations and the experiments that up to 30% of the inlet tube rows heat-exchange surface area do not participate in heat transfer. The tests conducted at the full-scale condensing units have corroborated this fact. This effect must be accounted for when designing and arranging corresponding cross-flow heat exchangers with cooling condensation.

We used real-time reverse transcriptase (RT)-polymerase chain reaction (PCR) to detect infectious bursal disease virus (IBDV) strains. The LightCycler (Roche) and hybridization probe system (Roche, Molecular Biochemicals) were used. A mutation probe labeled with fluorescein and an anchor probe labeled with Red-640 dye were prepared for each of the STC, Del E, D78, and Bursine 2 viral sequences. The mutation probes were designed to hybridize to nucleotides that encode the hydrophilic B region of VP2 for each virus. The anchor probes were designed to a relatively conserved region immediately downstream from the mutation probes. When hybridized to the RT-PCR product, a mutation and anchor probe pair produced fluorescence resonance energy transfer that was detected by the LightCycler instrument. Because they were designed to have a lower melting temperature (Tm), the mutation probes dissociated from the template before the anchor probes. The Tm values of the four mutation probes for each of their homologous viruses (exact sequence match) were STC, 69.3 +/- 1.2 C; D78, 67.8 +/- 0.9 C; Del E, 65.5 +/- 0.6 C; and Bursine 2, 71.7 +/- 0.4 C. These values were compared with the Tm values observed for a particular probe and heterologous virus. If the Tm values observed for heterologous viruses were within two standard deviations of the Tm for the probe and its homologous virus, the nucleotide sequences of the viruses were considered to be similar. If they were below two standard deviations, they were considered to have one or more nucleotide mutations. The results indicated that the STC and Variant Vax BD viruses have similar genetic sequences at the hydrophilic B region. Likewise, Bursine 2, Bursine, Bursine+, BioBurs, BioBurs W, BioBurs AB, and IBDV Blen have similar nucleotide sequences in this region. The Tm values obtained for the D78 and Del E mutation probes with heterologous viruses indicated that none of the viruses tested had nucleotide sequences that matched these probes. Because the mutation probes were designed to bind to a region that encodes a neutralizing epitope, viruses with similar sequences were expected to have antigenically similar epitopes.

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Research Papers An Improved Version of the k-W Model of Turbulence J. O. Ilegbusi, J. O. Ilegbusi Imperial College of Science and Technology, London SW7, England Search for other works by this author on: This Site PubMed Google Scholar D. B. Spalding D. B. Spalding Imperial College of Science and Technology, London SW7, England Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information J. O. Ilegbusi Imperial College of Science and Technology, London SW7, England D. B. Spalding Imperial College of Science and Technology, London SW7, England J. Heat Transfer. Feb 1985, 107(1): 63-69 (7 pages) https://doi.org/10.1115/1.3247404 Published Online: February 1, 1985 Article history Received: August 29, 1983 Online: October 20, 2009

A description is given of the principle and a preliminary embodiment of a flow-visualization technique in which the test body is pulled through water.Initially, dyed and undyed parts of the water are separated by a plane horizontal interface; as the body emerges from below this interface, it carries dyed fluid upwards in its wake. A succession of photographs reveals the nature of the flow.In principle, the flow is steady in a frame fixed relative to the body, and unsteady in one relative to the tank and the initial interface. Interpretation of the experimental results must therefore proceed by way of an analysis in which the steady-state equations are solved for velocity and turbulence quantities but an unsteady-state equation is solved for the dye concentration.Preliminary results are reported for the flows behind a wedge and behind a bar. They reveal that these particular flows are unsteady even in the body-fixed coordinate frame, being strongly oscillatory.

Numerical prediction of the heat transfer to low-Prandtl-number fluids has been carried out. A one-equation (k) turbulence model in the near-wall region and a two-equation (k ∼ e) turbulence model In the core region are employed. Many expressions proposed in the literature for the Prt numbers are examined. The fully developed temperature profiles obtained are compared with experimental results In the ranges Pr = 0.019–0.029 and Re = 40,000–400,000. The following Prt relations are finally recommended: the Aoki and Reynolds expressions in the range Re = 40,000–170,000 and the relation proposed by Jischa and Rieke for Re = 170,000–260,000. The Nusselt number results are compared with the experimental data In the literature and the agreement is good.