Vibration effects on the average heat transfer characteristics of the natural convection field in a square enclosure

In order to study the chaotic behavior of vibrational thermal convection in a square enclosure, a calculation method and the features of the average Nusselt number with vibration frequency were precisely examined. In the computation, the Prandtl number, the Rayleigh number, and the vibration Grashof number were held constant at 0.71, 10⁴, and 10⁶, respectively. The angular frequency of vibration was changed in the range between 10 and 7680. The results showed that the phenomena could be predicted with the calculation method adopted in this paper and the change in the time‐dependent characteristics of surface‐averaged Nusselt number with the angular frequency of vibration could be analyzed well with the power spectra. These changes were characterized by the five regimes proposed by Fu and Shieh. Moreover, it was clarified that the region where the hysteresis phenomena were detected corresponded to the one where the variation of the surface‐averaged Nusselt number was irregular and aperiodic. © 2000 Scripta Technica, Heat Trans Asian Res, 29(7): 545–558, 2000     

Archiving of food samples from restaurants and caterers--quantitative profiling of outbreaks of foodborne salmonellosis in Japan

The Ministry of Health, Labor and Welfare (former MHW) of Japan issued a Directive in 1997 advising restaurants and caterers to freeze portions of both raw food and cooked dishes for at least 2 weeks. This system has been useful for determining vehicle foods at outbreaks. Enumeration of bacteria in samples of stored food provide data about pathogen concentrations in the implicated food. Data on Salmonella concentrations in vehicle foods associated with salmonellosis outbreaks were collected in Japan between 1989 and 1998. The 39 outbreaks that occurred during this period were categorized by the settings where the outbreaks took place, and epidemiological data from each outbreak were summarized. Characteristics of outbreak groups were analyzed and compared. The effect of new food-storage system on determination of bacterial concentration was evaluated. Freezing and nonfreezing conditions prior to microbial examination were compared in the dose-response relationship. Data from outbreaks in which implicated foods had been kept frozen suggested apparent correlation between the Salmonella dose ingested and the disease rate. Combined with results of epidemiological investigation, quantitative data from the ingested pathogen could provide complete dose-response data sets.     

Characteristics of enterotoxin H-producing Staphylococcus aureus isolated from clinical cases and properties of the enterotoxin productivity

Staphylococcal enterotoxin H (SEH) is predicted to be involved in staphylococcal food poisoning. To characterize SEH-producing Staphylococcus aureus isolates from staphylococcal food poisoning cases in Japan, we investigated the relationship between SEH production and coagulase serotype, which is an epidemiological marker, and compared the properties of SEH production with those of staphylococcal enterotoxins A (SEA) and B (SEB). SEH production was determined by a newly developed sandwich enzyme-linked immunosorbent assay. Eighty-six (59.7%) of 144 isolates from staphylococcal food poisoning cases produced SEH. Seventy-one of the SEH-producing isolates simultaneously produced SEA, SEB, or both. All SEH-producing isolates belonged to coagulase type VII, which was the predominant type, representing 99 (68.8%) of 144 isolates. The amount of SEH produced in brain heart infusion was almost the same as the amount of SEA and approximately 10-fold lower than that of SEB. SEH and SEA were produced mainly during the late exponential phase of growth, whereas SEB was produced mostly during the stationary phase. The production levels of SEH and SEA were gradually affected by decreases in water activity, but the production of SEB was greatly reduced under conditions of low water activity. These findings indicate that SEH-producing S. aureus isolates are of high prevalence in staphylococcal food poisoning cases. Given the unique epidemiological characteristic of these isolates, SEH and SEA probably are responsible for food poisoning.     

Current status of seismic and borehole measurements for HDR/HWR development

Seismic and borehole measurements provide significant information about HDR/HWR reservoirs that is useful for reservoir development, reservoir characterization, and performance evaluation. Both techniques have been widely used during all HDR/HWR development projects. Seismic measurements have advanced from making passive surface measurements during hydraulic fracturing to making passive observations from multiple boreholes during all phases of HDR/HWR development, as well as active seismic measurements to probe regions of the reservoir deemed to be of interest. Seismic data provide information about reservoir extent, locations and orientations of significant fractures, and areas of thermal drawdown. Recent advances include the ability to examine structures within the seismically active zone using statistics-based techniques and methods such as seismic tomography. Seismic method is the only means to obtain direct information about reservoir characteristics away from boreholes. Borehole measurements provide high-resolution information about reservoir characteristics in the vicinity of the borehole. The ability to make borehole measurements has grown during the course of HDR/HWR development as high temperature tools have been developed. Temperature logging, televiewer logs, and electrical property measurements have been made and shown to provide useful information about locations of fractures intersecting wellbores, and regions where water leaves and enters injection and production wellbores, respectively.     

Reverse osmosis performance and chlorine resistance of new ternary aromatic copolyamides comprising 3,3′‐diaminodiphenylsulfone and a comonomer with a carboxyl group

The preparation of asymmetric flat membranes from a series of novel aromatic polyamides comprising 3,3′‐diaminodiphenylsulfone and a comonomer with a carboxyl group(&BOND;COOH) were studied and the measurements of reverse osmosis (RO) performance and chlorine resistance were carried out. It was confirmed that the introduction of comonomer with a carboxyl group (MC or T_m) to the aromatic polyamides (3I or 3T) comprising 3,3′‐diaminodiphenylsulfone was very effective for the improvement of its RO performance. In particular, 3T‐MC(30), which was prepared from terephthaloyl dichloride and mixed diamine components of 3,3′‐diaminodiphenylsulfone and 3,5‐diaminobenzoic acid, exhibited not only some potential for sea water desalination (FR = 159 L/m² day, Rj = 98.3%) but also higher chlorine resistance than conventional Nomex‐type aramid [MI‐MC(0)]. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 505–513, 2001     

Quasi‐static and chaotic characteristics of the natural convection field in a vertical slot

In this paper, the time‐dependent characteristics of natural convection in a vertical slot with hot and cold side walls were experimentally examined. In the experiment, the test liquid was a glycerine–water mixture (80 wt%) and the Prandtl number in the center of the slot was held constant at 295. On the other hand, the Grashof number was varied in the range between 370 and 3.06 × 10³. As a result, it was revealed that low‐pass filtering for the time evolution data of temperature made it possible to compute the largest Lyapunov exponents precisely. Secondary flow cells are observed in both chaotic and nonchaotic regions. Moreover, the secondary flow cells appeared in regions where the power spectrum of temperature fluctuation was regarded as significant and where the autocorrelation function decreased rapidly with time. © 2000 Scripta Technica, Heat Trans Asian Res, 30(1): 40–53, 2001     

Structural Biology of DNA (6-4) Photoproducts Formed by Ultraviolet Radiation and Interactions with Their Binding Proteins

Exposure to the ultraviolet component of sunlight causes DNA damage, which subsequently leads to mutations, cellular transformation, and cell death. DNA photoproducts with (6-4) pyrimidine-pyrimidone adducts are more mutagenic than cyclobutane pyrimidine dimers. These lesions must be repaired because of the high mutagenic potential of (6-4) photoproducts. We here reviewed the structures of (6-4) photoproducts, particularly the detailed structures of the (6-4) lesion and (6-4) lesion-containing double-stranded DNA. We also focused on interactions with their binding proteins such as antibody Fabs, (6-4) photolyase, and nucleotide excision repair protein. The (6-4) photoproducts that bound to these proteins had common structural features: The 5''-side thymine and 3''-side pyrimidone bases of the T(6-4)T segment were in half-chair and planar conformations, respectively, and both bases were positioned nearly perpendicularly to each other. Interactions with binding proteins showed that the DNA helices flanking the T(6-4)T segment were largely kinked, and the flipped-out T(6-4)T segment was recognized by these proteins. These proteins had distinctive binding-site structures that were appropriate for their functions.     

Identification and Field Evaluation of Sex Pheromone Components of the Pear Barkminer Moth, <Emphasis Type="Italic">Spulerina astaurota</Emphasis>

The pear barkminer moth, Spulerina astaurota Meyrick (Gracillariidae: Gracillariinae), is a harmful pest of the Asian-pear tree. Pheromone components of the female were analyzed by gas chromatography (GC) with an electroantennographic (EAG) detector and GC coupled with mass spectrometry. The analyses of a crude pheromone extract and those of a fractionated extract on a Florisil column indicated three EAG-active components, tetradecadien-1-ol, its acetate, and an aldehyde derivative. Characteristic fragment ions in the mass spectra of the dienyl compounds and derivatives with 4-methyl-1,2,4-triazoline-3,5-dione revealed double bonds at the 9- and 11-positions. By comparing the chromatographic behaviors to those of four authentic geometrical isomers, which were synthesized by three different routes starting from 1,8-octanediol or 1,9-nonanediol, the configuration of each natural component was assigned to be 9Z,11Z; i.e., it was concluded that the S. astaurota females secreted (9Z,11Z)-9,11-tetradecadien-1-ol (Z9,Z11-14:OH) as a main pheromone component, and the acetate and aldehyde derivatives (Z9,Z11-14:OAc and Z9,Z11-14:Ald) as minor components. This identification was confirmed by a field evaluation of the synthetic pheromone. While the male moths could be attracted to a lure baited with Z9,Z11-14:OH alone, Z9,Z11-14:OAc showed a strong synergistic effect on the attraction. Among the lures tested, the mixture of alcohol and acetate in a ratio of 7:3 exhibited the strongest attraction. Addition of Z9,Z11-14:Ald in the mixture did not significantly increase the number of males attracted. Furthermore, the field test indicated that some contamination of a geometrical isomer of the alcohol did not impair the activity of the binary mixture with the 9Z,11Z configuration.