Notice of RetractionAnalysis of Shear Behavior for Medium and Heavy Plate
With the continuous development of large-scale software, the theory of finite element, and computer speed, so the accuracy has been continuously improved for numerical analysis of finite element. The numerical analysis method of finite element has become increasingly widely used in dealing with practical engineering problems, the calculated model was established by elastic-plastic theory under taking into account the factors including materials work-hardening, the velocity of cutting edge and so on. The law of stress and deformation has done a detailed analysis of deformation zone during shearing continuous casting slab based on the model. It can gain the largest shear force by the travel curve of shear stress, and seek the numerical simulation method for tilting shear force and energy parameters of the shearing machine, reach the purpose of less experiment and reducing the cost analysis. The results provide an effective way to determine the maximum shear stress and enhancement the useful rate of the cutting edge.
Stability-Based Spindle Design Optimization
Prediction of stable cutting regions is a critical requirement for high-speed milling operations. These predictions are generally made using frequency-response measurements of the tool-holder-spindle set obtained from a nonrotating spindle. However, significant changes in system dynamics occur during high-speed rotation. In this paper, a dynamic high-speed spindle-bearing system model is elaborated on the basis of rotor dynamics prediction and readjusted on the basis of experimental modal identification. The dependency of dynamic behavior on speed range is then investigated and determined with accuracy. Dedicated experiments are carried out in order to confirm model results. They show that dynamic effects due to high rotational speed and elastic deformations, such as gyroscopic coupling and spin softening, have a significant influence on spindle behavior. By integrating the modeled speed-dependent spindle transfer function in the chatter vibration stability approach ofAltintas and Budak (1995, CIRPS Ann, 44(1), pp. 357-362), a new dynamic stability lobe diagram is predicted. Significant changes are observed in the stability limits constructed using the proposed approach and allow accurate prediction of cutting conditions to be established. Finally, optimization studies are performed on spindle design parameters in order to obtain a chatter vibration-free cutting operation at the desired speed and depth of cut for a given cutter.
Comparison of a Radiometric Procedure with Conventional Methods for Identification of Neisseria
A radiometric procedure was compared with the conventional cystine tryptic agar (CTA) sugar fermentation method for identification of Neisseria species. Four different ATCC cultures of Neisseria were identified by both procedures with identical results. The only difference noted was that the radiometric procedure required 3 h for completion, whereas the conventional CTA sugar method required overnight incubation. The radiometric procedure was also compared with the fluorescent antibody (FA) and CTA methods for identification of Neisseria gonorrhoeae. The organisms examined were gram-negative, oxidase-positive diplococci isolated from 49 clinical specimens sent to the laboratory for bacteriological analysis. Results obtained by both CTA and FA procedures were comparable. However, the radioisotope method appeared to be superior to the other two methods in that only one isolate identified as positive by both the CTA and FA methods was not identified radiometrically, whereas four isolates positive by the radiometric method were not identified by the other two procedures. Thus, a total of seven more positive identifications were made radiometrically than by either of the two other methods. All positive identifications were confirmed by a reference laboratory. These results indicate that the radiometric procedure is more rapid and reliable as compared with both the CTA and direct FA methods and, thus, may serve as a valuable addition to the methodology available for diagnostic microbiology.