Search

A newly proposed experimental method to determine the inverted annular flow does not require the diversion of the fluid flow into a bypass. The method determines the inverted annular flow by means of a fast power transient. This reduces the possible variations in the boiling surface conditions due to continuous heating of the tube. A combination of this method and the conventional hot-patch method yields a complete steady-state inverted annular flow.

This article reports our studies on the performance of isomorphous Cu–Ni alloy during sliding and erosive wear processes with attempt to correlate its wear behaviour with the electron work function (EWF). EWF, mechanical behaviour and wear resistance of the Cu–Ni alloy with respect to the concentration of Ni were measured using ultraviolet photoelectron spectroscopy, micro-indenter, pin-on-disc and air-jet testers, respectively. It was demonstrated that EWF, hardness and Young’s modulus of the alloy increased as the concentration of Ni increased. During solid-particle erosion tests, the wear resistance of the alloy was enhanced with an increase in the Ni concentration, corresponding to an increase in EWF. However, an opposite trend was observed during sliding wear tests, which was ascribed to the formation of oxide scale that affected the sliding wear resistance. [ABSTRACT FROM AUTHOR]

Existing models for predicting end breakage rates in spinning give unrealistic values when considering the effects of changes in count or speed on the worsted ring frame. A new approach to predicting end breaks gives results that are closer to experience values. The most important factor in determining end breaks is yarn strength variation, followed by mean yarn strength and spinning tension. [ABSTRACT FROM PUBLISHER]

Abstract: Objective: To establish an acute rejection model after kidney transplantation in the rat using a modified method of ureterovesical anastomosis. Methods: Thirty-nine Wistar rat donors, were transplanted into 70 male SD rats. Wistar rats (group 1; n = 18) underwent harvest of both kidneys, cold perfusion, and transplantation into 36 SD rats. Wistar rats (group 2; n = 18) underwent left kidney harvest, cold perfusion and transplantation into 18 SD rats. Groups 1 and 2 did not receive immunosuppression after transplantation. Six kidneys were harvested from 3 Wistar rats (group 3), were transplanted into 6 SD rats that were treated with CsA (5 mg/kg per day) postoperatively, and humanely killed at 21 days. There were 10 SD in sham operated rats (group 4). The renal allograft vein was end-to-end anastomosed to the recipient renal vein using an epidural catheter. The renal allograft was anastomosed end-to-side to the recipient abdominal aorta with an abdominal aortic flap. The renal allograft ureterovesical flap was directly inserted into the recipient bladder, and attached by 4–5 interrupted sutures. The recipient''s right kidney vessels were ligated at 3 days postoperatively. Results: The success rates were 91.7% and 88.9% in groups 1 and 2, respectively. Except for the time for removal of the renal allografts, the operative durations and warm ischemia times differed insignificantly between both groups (P > .05). Blood creatinine levels increased significantly after kidney transplantation in groups 1 and 2 compared with the sham operated and CsA-treated cohorts (P < .01), but insignificantly between groups 1 and 2 (P > .05). Conclusions: A dual renal allograft model was established in the rat using a modified ureterovesical anastomosis. The technique can be reproduced reliably, reducing costs and shorten using overall operative duration. [Copyright &y& Elsevier]

Abstract: In the Wenchuan area in SW China, an abundance of loose co-seismic landslide debris was present on the slopes after the Wenchuan earthquake, which in later years served as source material for rainfall-induced debris flows or shallow landslides. Slopes composed of Cambrian sandstones and siltstones intercalated with slates appeared to be most susceptible to co-seismic landsliding. A total of 20 debris flows are described in this paper; all were triggered by heavy rainfall on 13th of August 2010. Field reconnaissance and measurements, supported by aerial photo interpretation, were conducted to identify the locations and morphological characteristics of the debris flow gullies in order to obtain information about surface area and volume of landslides and the debris flows. The debris flows in the study area were initiated by two processes: a) run-off erosion on co-seismic landslide material, and concentrated erosion of landslide debris in steep channels; b) new landslides that transform into debris flows. The volume of debris flow deposits on individual fans varies by many orders of magnitude. The smallest deposit has a volume of from 5760 to 3.1millionm3. A comparison of the measured volumes, deposited on the fan with the volumes of debris stored in the catchment shows the huge potential for future debris flow activity. Whilst there is a weakly significant positive correlation between these two volumes, no significant statistical correlation could be established between volumes of debris flow deposits and other morphometric parameters of the catchment. A catastrophic debris flow catchment (the Wenjia catchment) was selected as an extreme case to show in detail the mechanism of debris flow formation as a result of intensive erosion in loose material, which was deposited by a rock avalanche during the 2008 Earthquake event. Analyses of the meteorological conditions that triggered these debris flows show one day antecedent precipitation varying between 67.7 and 137.6mm, with a mean rainfall intensity of about 7.3 to 22.5mm/h. A rainfall event with peak intensity of 38.7mm/h triggered the largest debris flow event. Rainfall data related to five debris flow events in the Wenjia torrent was used to establish a primary rainfall intensity–duration relationship for the triggering of debris flows, which was compared to other rainfall duration thresholds from other parts of the world. In the discussion emphasis is laid on the need to unravel the process mechanisms which initiated the debris flows for a better understanding and assessment of meteorological thresholds. [Copyright &y& Elsevier]