http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Stefano d’Ambrosio,Alessandro Ferrari,Alessandro Mancarella,Antonio Mittica 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.1
An experimental investigation has been carried out to highlight the effects of different injection strategies on the performance and emissions of a low compression ratio Euro 5 diesel engine operated with high EGR rates. Rate-shaped main injections, achieved with piezoelectric and solenoid injectors by means of boot and injection fusion, respectively, as well as optimized multiple injection patterns have been compared. The results of the comparisons, performed with reference to a state-of-the-art double pilot-Main (pM) strategy, are presented in terms of engine-out exhaust emissions, combustion noise (CN) and fuel consumption. Rate-shaped main injections, when included in delayed multiple injection patterns, have shown a minor influence on reducing NOx, while a slight deterioration in soot has been found. Both a double pilot and a boot injection schedule have been able to reduce CN at low loads. A higher reduction in CN has been obtained with an injection fusion event. Finally, DoE optimized triple and quadruple injection strategies have led to improved soot-NOx trade-offs, with respect to the pM calibration. In fact, splitting the injection helps to entrain air inside the fuel plumes, thus creating locally leaner mixture (less prone to forming soot) and allowing increasing the EGR rates (reducing NOx formation).
Transanal Endoscopic Microsurgery: Endoscopy Assisted Treatment of Colorectal Anastomotic Stenosis
Giancarlo D’Ambrosio,Antonietta Lamazza,Rossella Palma,Andrea Picchetto,Cristina Panetta,Antonello Trecca,Stefano Pontone,Emanuele Lezoche 대한대장항문학회 2020 Annals of Coloproctolgy Vol.36 No.4
Transanal endoscopic microsurgery (TEM) is a type of natural orifice transluminal endoscopic surgery, developed for rectal tumors and used also to treat other rectal diseases. Anastomotic complications after colorectal surgery, including stenosis, represent a challenging problem. We present the case of a 36-year-old woman with a diagnosis of Hirschsprung disease that was submitted to a modified Duhamel operation. A postoperative barium enema showed a complete stricture of the anastomosis that was impossible to resolve by flexible endoscopic approach. Then an intraoperative endoscopic approach to facilitate the localization of preanastomotic colon (proximal colon from the anastomosis) was performed by a small colotomy and the colonic recanalization was obtained by the creation of a neo-anastomosis by TEM, under fluoroscopic-endoscopic control. The patient underwent a control barium enema showing regular retrograde transit of contrast medium without evidence of stenosis. In our experience, transanal approach by TEM-colonoscopy assisted is safe and feasible and represents a model of combined minimally invasive technique.
Luca Ambrosio,Gianluca Vadalà,Javad Tavakoli,Laura Scaramuzzo,Giovanni Barbanti Brodano,Stephen J. Lewis,So Kato,Samuel K. Cho,S. Tim Yoon,김호중,Matthew F. Gary,Vincenzo Denaro 대한척추신경외과학회 2024 Neurospine Vol.21 No.1
Objective: To evaluate the global practice pattern of wound dressing use after lumbar fusion for degenerative conditions. Methods: A survey issued by AO Spine Knowledge Forums Deformity and Degenerative was sent out to AO Spine members. The type of postoperative dressing employed, timing of initial dressing removal, and type of subsequent dressing applied were investigated. Differences in the type of surgery and regional distribution of surgeons’ preferences were analyzed. Results: Right following surgery, 60.6% utilized a dry dressing, 23.2% a plastic occlusive dressing, 5.7% glue, 6% a combination of glue and polyester mesh, 2.6% a wound vacuum, and 1.2% other dressings. The initial dressing was removed on postoperative day 1 (11.6%), 2 (39.2%), 3 (20.3%), 4 (1.7%), 5 (4.3%), 6 (0.4%), 7 or later (12.5%), or depending on drain removal (9.9%). Following initial dressing removal, 75.9% applied a dry dressing, 17.7% a plastic occlusive dressing, and 1.3% glue, while 12.1% used no dressing. The use of no additional coverage after initial dressing removal was significantly associated with a later dressing change (p < 0.001). Significant differences emerged after comparing dressing management among different AO Spine regions (p < 0.001). Conclusion: Most spine surgeons utilized a dry or plastic occlusive dressing initially applied after surgery. The first dressing was more frequently changed during the first 3 postoperative days and replaced with the same type of dressing. While dressing policies tended not to vary according to the type of surgery, regional differences suggest that actual practice may be based on personal experience rather than available evidence.
A Computational Efficient General Wheel-Rail Contact Detection Method
Joao Pombo,Jorge Ambrosio 대한기계학회 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.1S
The development and Implementation of an appropriate methodology for the accurate geo-metric description of track models is proposed in the framework of multibody dynamics and It includes the representation of the track spaual geometry and Its irregula갸샫s The wheel and rail surfaces are parameterized to represent any wheel and rail profiles obtained from direct measurements or design requirements A fully generic methodology to determine, online during the dynamic simulation, the coord mates of the contact points, even when the most general three dimensional motion of the wheelset with tespect to the tails is proposed This methodology is applted to study specific Issues in railway dynamics such as the flange contact problem and lead and lag contact configurations A formulation for the description of the normal contact forces, which result from the wheel-rail Interaction, is also presented The tangential creep forces and moments that develop in the wheel-rail contact area are evaluated using Kalker linear theory, Heuristic force method, Polach formulation The methodology is Implemented in a general multibody code The discussion is supported through the application of the methodology to the railway vehicle ML95, used by the Lisbon metro company<br/>
Al2O3-ZrO2 nanocomposites produced by solution combustion synthesis followed by ultrasonic milling
Sara Biamino,Elisa Paola Ambrosio,Diego Manfredi,Paolo Fino,Claudio Badini 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.2
Zirconia toughened alumina materials (ZTA) have been produced by solution combustion synthesis (SCS). SCS has proved to be a rather rapid and simple method to produce nano-structured ceramic oxides powders. Its main drawback is a limited sinterability of the powder due to aggregation of the nanometric grains into larger particles characterized by irregular shapes. It was found out that when coupling the preparation of ZTA nanocomposites by SCS with ultrasonic milling it is possible to improve the powder sinterability. The effect of ultrasonic irradiation on the powders was observed by BET and SEM analyses,and by its effect on the final density.
A hybrid numerical flux for supersonic flows with application to rocket nozzles
Ferrero, Andrea,D'Ambrosio, Domenic Techno-Press 2020 Advances in aircraft and spacecraft science Vol.7 No.5
The numerical simulation of shock waves in supersonic flows is challenging because of several instabilities which can affect the solution. Among them, the carbuncle phenomenon can introduce nonphysical perturbations in captured shock waves. In the present work, a hybrid numerical flux is proposed for the evaluation of the convective fluxes that avoids carbuncle and keeps high-accuracy on shocks and boundary layers. In particular, the proposed flux is a combination between an upwind approximate Riemann problem solver and the Local Lax-Friedrichs scheme. A simple strategy to mix the two fluxes is proposed and tested in the framework of a discontinuous Galerkin discretisation. The approach is investigated on the subsonic flow in a channel, on the supersonic flow around a cylinder, on the supersonic flow on a flat plate and on the flow in a overexpanded rocket nozzle.