Determination of the SSME high pressure oxidizer turbopump bearing temperature

The SSME high pressure liquid oxygen turbopump (HPOTP) bearings sometimes wear and experience heating and oxidation of the ball and raceway surfaces. So far it has been impossible to measure the temperature of the bearings directly during operation of the turbopumps. However, a method was developed for determining the surface temperature of the bearings from the composition of the oxides using oxidation samples for calibration and Auger Electron Spectroscopy (AES) for chemical analysis

Prospective randomized study evaluating an absorbable cyanoacrylate for use in vascular reconstructions

BackgroundAn easy-to-use vascular sealant with good safety and efficacy is needed to prevent anastomotic bleeding in vascular surgery. This study evaluated the safety and efficacy of cyanoacrylate surgical sealant in establishing hemostasis of expanded polytetrafluoroethylene to arterial vascular anastomoses in arteriovenous (AV) grafts and femoral bypass grafts.MethodsThis multicenter, randomized, controlled, open-label study was conducted in a hospital setting at 12 sites: 10 in the United States and 2 in Europe. A total of 151 patients undergoing femoral bypass procedures or AV shunt procedures for hemodialysis access using expanded polytetrafluoroethylene grafts were randomized 2:1 to receive cyanoacrylate surgical sealant or the control (oxidized cellulose) between April 26, 2004, and January 18, 2005. Randomization was stratified by clinical site and type of procedure. After the anastomosis, cyanoacrylate surgical sealant or the control was applied to all anastomosis sites for patients undergoing femoral bypass procedures and to only the arterial anastomosis sites for patients undergoing AV shunt procedures. The primary end point was the elapsed time from clamp release to hemostasis. Secondary end points were the proportion of patients achieving hemostasis at t = 0 (immediate), 1, 5, or 10 minutes after clamp release, use of additional adjunctive measures to achieve hemostasis, and occurrence of adverse events.ResultsBaseline demographics and clinical characteristics showed that the two treatment groups were similar at baseline. The mean time from clamp release to hemostasis was 119.3 seconds with cyanoacrylate surgical sealant vs 403.8 seconds with the control (P < .001). Immediate hemostasis was achieved in 54.5% of patients receiving cyanoacrylate surgical sealant and in 10% of those receiving the control. The proportion of patients requiring additional adjunctive measures was lower with cyanoacrylate surgical sealant, and the occurrence of adverse events was similar in both groups.ConclusionsThis study demonstrates that cyanoacrylate surgical sealant is effective at reducing the time to hemostasis and achieving immediate hemostasis in AV shunt and femoral bypass procedures and that it is safe for internal use. Cyanoacrylate surgical sealant is an easy-to-use vascular sealant with good safety and efficacy that significantly decreases anastomotic bleeding in vascular surgery

Virtual Engineering in Skills Acquisition and Development in the Career of the Rotorcraft Engineer

As the complexity of engineering systems grows, engineers increasingly need to be able to use a range of tools in order to reduce the costs, and associated risks, as they work in the various phases of the engineering life-cycle. In order to help engineers operate successfully within this product lifecycle, there have been significant developments in modelling simulation tools. Integrating these tools in a Virtual Engineering (VE) environment allows engineers to examine the potentially conflicting requirements of the different phases of the life-cycle, to develop a co-ordinated approach to requirements capture and product design through to identifying potential costly problems that could occur later in the development and operations phases. Technical skills development to use these tools is key to this process. This paper presents the experiences, learning outcomes and lessons learned in the development and implementation of bespoke rotorcraft engineering training programmes. The programmes were designed using a Problem Based Learning (PBL) framework where knowledge and skills are gained through solving problems. Four cases studies are presented in the paper, demonstrating how this PBL/VE approach can be used in the training programmes. Consideration of the future use of VE tools is provided together with future challenges for their successful application

Neural development - One year on

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Near-infrared integral field spectroscopy of Massive Young Stellar Objects

We present medium resolution ($R\approx5300$) $K$-band integral field spectroscopy of six MYSOs. The targets are selected from the RMS survey, and we used the NIFS on the Gemini North telescope. The data show various spectral line features including Br$\gamma$, CO, H$_2$, and \mbox{He\,{\sc i}}. The Br$\gamma$ line is detected in emission in all objects with $v_\mathrm{FWHM}\sim100$ -- 200 kms$^{-1}$. V645 Cyg shows a high-velocity P-Cygni profile between -800 kms$^{-1}$ and -300 kms$^{-1}$. We performed three-dimensional spectroastrometry to diagnose the circumstellar environment in the vicinity of the central stars using the Br$\gamma$ line. We measured the centroids of the velocity components with sub-mas precision. The centroids allow us to discriminate the blueshifted and redshifted components in a roughly east--west direction in both IRAS 18151--1208 and S106 in Br$\gamma$. This lies almost perpendicular to observed larger scale outflows. We conclude, given the widths of the lines and the orientation of the spectroastrometric signature, that our results trace a disc wind in both IRAS 18151--1208 and S106. The CO $\nu=2-0$ absorption lines at low $J$ transitions are detected in IRAS 18151--1208 and AFGL 2136. We analysed the velocity structure of the neutral gas discs. In IRAS 18151--1208, the absorption centroids of the blueshifted and redshifted components are separated in a direction of north-east to south-west, nearly perpendicular to that of the larger scale $H_2$ jet. The position-velocity relations of these objects can be reproduced with central masses of 30 M_{\sun} for IRAS 18151--1208 and 20 M_{\sun} for AFGL 2136. We also detect CO $\nu=2-0$ bandhead emission in IRAS 18151--1208, S106 and V645 Cyg. The results can be fitted reasonably with a Keplerian rotation model, with masses of 15, 20 and 20 M_{\sun} respectively.Comment: 17 pages, 10 figures, accepted by MNRA