Mechanics of Gear lobbing

The exacting demands for producing accurate gears make it necessary to determine the cutting forces coming on the hob-shaft which is the weakest element subjected to severe bending and torsion. The authors, with the help of a specially designed hobbing dynamometer, have investigated the magnitude and nature of the tangential and radial component of cutting force during the conventional hobbing process

Characteristics of Laminated Sheet Metals in Tensile Deformation

Introduction Recently, laminated sheet metals have been used in various fields, for example, as vibration isolation sheet, because of their special properties which cannot be obtained by conventional materials. However, a method for evaluating workability of the laminated sheet metals has not been established. Only a few investigations have been made. Hawkins and Wright [1] investigated deep drawability of adhesive bonded and clad sheet metals of copper and mild steel. Hiraiwa and Kondo [2,3] also studied deep drawability and found that the limiting drawing ratio (LDR) does not always obey the composite law and that the LDR becomes larger because deformation of the sheet metal with a small LDR is affected by that with a large LDR. This trend is more remarkable when the difference in the workhardening exponents of the sheet metals is larger. Semiatin and Piele

Arterio-Venous Fistula Using Nonpenetrating Titanium Clips (VCS)

Rezumat Fistulã arterio-venoasã cu clipuri metalice nepenetrante Accesul vascular la hemodializã este însoåit în continuare de o morbiditate foarte mare. Tromboza datoratã hiperplaziei neointimale este una din principalele cauze de nefuncåionalitate a accesului vascular. Scopul lucrãrii este de a prezenta tehnica realizãrii anastomozei arterio-venoase folosind clipurile de titan nepenetrante(VCS) şi rezultatul acesteia. Material şi metodã: Pacientului K.L. de 47 ani aflat în evidenåa Clinicii de Nefrologie din 2005 pentru insuficienåã renalã cronicã i s-a efectuat în octombrie 2006 o fistulã arteriovenoasã clasicã între artera radial şi vena cefalicã a antebraåului. Aceastã fistulã nu a funcåionat motiv pentru care în ianuarie 2007 s-a efectuat anastomoza arterio-venoasã cu clipuri de titan nepenetrante între artera brahialã şi vena medianã a antebraåului. Rezultate: Anastomoza a fost realizatã în 17 minute. Dupã declamparea arterelor s-a obåinut puls şi tril la nivelul venei mediane a antebraåului şi la nivelul venei cefalice. Nu au fost complicaåii intraoperatorii şi postoperatorii imediate. La 5 sãptãmâni postoperator s-a efectuat prima hemodializã. Fistula este funcåionalã la 58 de luni de la efectuarea ei. Concluzii: Realizarea anastomozelor arterio-venoase pentru acces la hemodializã cronicã cu material nepenetrant poate fi o soluåie de reducere a complicaåiilor postoperatorii şi de prelungire a patenåei fistulelor. Cuvinte cheie: hemodializã, fistulã arterio-venoasã, clipuri de titan nepenetrante Abstract Vascular access in haemodialysis is still accompanied by a high morbidityrate. Neointimal hyperplasia due to thrombosis is one of the main causes of vascular access failure. The purpose of this paper is to present the use of non-penetrating titanium clips (VCS) forthe creation of an arteriovenous fistula and its outcome. Materials and Methods: A male patient, 47 years old, with end-stage renal disease -ESRD -(2005) was addressed to our service, for a vascular access reintervention, after a failed forearm radio-cephalic fistula performed 3 months before. In January 2007, an arteriovenousfistula between thebrachial artery and themedian cubital vein using non-penetratingtitanium clips (Anastoclip VCS) was created. Results: The vascular anastomosis was performed in 17 min. After unclamping the artery, a solid pulse and consistent thrill were obtained at the level of the cubital fossa. The postoperative course was uneventful. The arteriovenous fistula remains functional 60 months post-surgery. Conclusions: The Anastoclip VCS system is versatile, safe to manipulate and enables fast anastomosis. Arteriovenous anastomosis performed with non-penetrating clips may be a solution with the potential to reduce postoperative complications and extend arteriovenous fistula patency in ESRD

An Optimal Approach towards Sequence Analysis

Abstract Dynamic programming is a form of recursion in which intermediate results are saved in a matrix where they can be refereed to later by the program. The paper aims at presenting the calculation of the edit distance between two given strings which includes a cost factor for the different edit operations like copy, insert and delete. The method used in this paper is a form of dynamic programming which includes the formation of a recurrence relation which is then used to represent the problem in a tabular form. In the next step the table is used to trace back to get the possible combinations of edit operations and the one which involves the least cost can be considered the appropriate one

Performance of a Low Heat Rejection Diesel Engine With Air Gap Insulated Piston

Introduction The second law requirement of Thermodynamics necessitates the inevitable heat loss to the coolant to realise work output. Any saving in this part of the energy distribution would either increase the energy lost through exhaust gases or increase the power output. Considerable efforts are under way to reduce heat loss to the coolant by various researchers. However, the results are a little confusing as to whether the insulation would improve or deteriorate thermal efficiency. The two approaches that are being pursued to decrease heat rejection are (1) ceramic coating and (2) air gap insulation. Both these methods are still having problems. Ceramic coatings are found to be peeling off over a period of operation. There are serious problems of leakage of gases in the case of air gap insulation. A two zone combustion model was used by A study of the existing literature on LHR engines thus reveal