Impingement heat transfer by jet issuing from a cross-shaped nozzle

Heat transfer characteristics and flow patterns were measured over a plate for various separation distances between the nozzle exit and target plate when air issues from a sharp-edged cross-shaped nozzle and impinges on a plate. The local heat transfer coefficients in the radial direction for different circumferential positions were calculated using the wall temperatures measured by means of thermocouples, and flow patterns were observed using an oil-titanium IV oxide method. The isotherms of the infrared images were also measured using an infrared radiometer with a two-dimensional array of indium-antimony (InSb) sensors. The geometric axes were switched as a result of the self-induced velocity of a vortex filament; the convex corners became flat and the concave corners generated outward ejection. The distributions of the iso-heat transfer coefficient contours correspond well to the flow pattern and the isotherm contours. These contours extended diagonally and demonstrated the St. Andrew's cross pattern for short separations, subsequently changing to an octagonal pattern, and then becoming circular at large separations. The correspondence of the heat transfer characteristics to the flow behavior, as well as the heat transfer mechanism are also described. © 1998 Scripta Technica, Heat Trans Jpn Res, 27(3): 192–204, 1998     

Stepwise polymerization of propylene and ethylene with Cr(acetylacetonate)3/MgCl2–ethylbenzoate/diethylaluminium chloride catalyst system

During propylene polymerization with the Cr(acetylacetonate)₃/MgCl₂–Et₂AlCl–ethylbenzoate catalyst system which shows high isospecificity for propylene polymerization, it was found that the chain transfer and termination reactions can be neglected. Based on this result, some stepwise polymerizations of propylene and ethylene were carried out with the same catalyst system varying polymerization conditions. The resulting copolymers were separated by temperature rising elution fractionation (TREF) and afforded two fractions which were eluted at different temperatures. From the ¹³C NMR, DSC and GPC analyses of each fraction, it was considered that the corresponding block copolymer existed in the fraction eluted at higher temperature. © 2003 Society of Chemical Industry     

Concentration Dependence of the Diffusion Coefficient of Water in SiO2 Glass

The concentration dependence of water diffusion in SiO₂ glass was analyzed assuming that both molecular water and hydroxyl water can diffuse and that they are in equilibrium as interstitial and substitutional impurities. The equation obtained appears to be consistent with experimental observations of water diffusion in SiO₂ glass.     

HEAT TRANSFER IN A CONDUCTIVE-HEATING AGITATED DRYER

The heat transfers between the heating plane and the granular materials in both the “Stationary heating-plane type” and the “Moving heating-plane type” of the conductive-heating agitated dryers were discussed mainly from the view point of the scale-up of the dryer. Under the condition of complete mixing in the bed of bulk materials, the heat transfer models proposed for both the two types of dryers can predict the heat transfer coefficients in any sizes of the dryers. However, the complete mixing is not usually accomplished in the large scale of dryer. Hence, an “Incomplete mixing model” was proposed to estimate the effect of the incompleteness of mixing on the heat transfer coefficient. In this model, the incompleteness of mixing can be apparently taken into consideration only by increasing the contact time.     

Effects of conditioning factor on anthocyanin production in strawberry suspension cultures

To investigate the effects of the conditioning factor on anthocyanin production in the cultured strawberry, Fragaria ananassa cv Shikinari, cells were cultured in LS medium supplemented with a filtered conditioned broth. Anthocyanin accumulation was greatly enhanced using media conditioned for 5–8 days. This effect was promoted by increased concentrations of the conditioned broth. The amount of anthocyanin produced in a 100% conditioned broth was about eight times higher than in the control broth after 5 days. The substance that promoted anthocyanin accumulation in the conditioned medium was thermostable, because neither cell growth nor anthocyanin accumulation were affected by boiling for 10 min. Anthocyanin production was further enhanced by adding freeze-dried conditioned broth to freshly prepared LS medium; however, this conditioned broth affected cell growth only in the early phase of culturing. The content of peonidin-3-glucoside, a major anthocyanin, increased as the number of days the cell growth proceeded, while that of cyanidin-3-glucoside decreased. The contents of these two major anthocyanins were also changed by adding a preculture broth as a conditioning factor.     

Chloride permeability of concrete subjected to freeze-thaw damage

The effects of freezing and thawing cycling on the chloride permeability of normal weight and lightweight concretes were investigated by using the AASHTO T277 chloride permeability test method and the freeze-thaw test method similar to that recommended by ASTM C666. The results showed that the chloride permeability of the normal weight concretes having an air content of at least 5·3% changed little with the repeated cycles of freezing and thawing up to 618 cycles, irrespective of the presence and the type of mineral admixtures. It was also found that lightweight concretes made with fully-saturated expanded shale aggregates exhibited an extremely high chloride permeability at any air content, when they were subjected to a single freeze-thaw cycle. Furthermore, the type of microcracks developing in normal weight concretes exposed to the repeated freeze-thaw cycles was discussed.     

Kinetic study of isotopic exchange reaction between hydrogen and water vapor over a pt/sdbc hydrophobic catalyst sheet

The isotopic exchange reaction between hydrogen and water vapor was studied for the temperature range 313 K to 353 K using 2.2% platinum supported on a hydrophobic styrene-divinylbenzene copolymer (SDBC) sheet. With increasing relative humidity, the exchange rate increased, giving a stepped profile with a knee shape, and the reaction order with respect to hydrogen increased from almost zero to first order. In order to explain this unusual behavior, a simple kinetic model was proposed assuming that the water molecules are adsorbed in a multilayer on the platinum surface, and are subject to the exchange equivalent to finite number of layers. On the other hand, this multilayer of adsorbed water inhibits the transfer of HD to the platinum surface.     

Liver metastases from colon cancer with intra-bile duct tumor growth: radiologic features

PURPOSE: Our goal was to characterize the radiologic features of liver metastases from colon cancer with intrahepatic bile duct (IHBD) dilatation. METHOD: Radiologic findings of liver metastases from colon cancer with IHBD dilatation of four patients were compared with pathologic findings. RESULTS: The cause of bile duct dilatation in all cases was due to papillary tumor growth in the bile duct. In two patients, intra-bile duct tumor growth (IBDTG) was observed on imaging. In the other two patients, IBDTG was not observed, but a nontapered abrupt obstruction of a dilated bile duct was seen, corresponding to the microscopically proven papillary tumor growth in the ductal lumen. In three patients who underwent an extensive hepatic resection, there has been no recurrence. In one patient who had a nonanatomic limited resection, a recurrence was seen 1 year after surgery. CONCLUSION: When liver tumor with IBDTG is suspected on imaging, liver metastases should be considered in the differential diagnosis besides hepatocellular carcinoma or cholangiocellular carcinoma. Careful preoperative assessment for IBDTG by imaging is essential to determine the extent of surgical resection.