11 research outputs found
Influence of Carbon in Iron on Characteristics of Surface Modification by EDM in Liquid Nitrogen
No full textMany surface modification technologies have been proposed and carried out practically by CVD, PVD et.al. Carbonized layer has been made using EDM method. In this paper, to make the nitride layer by EDM some new trials were carried out using a titanium electrode in liquid nitrogen. Experiments were carried out on carbon steel (S45C), pure iron and cast iron. TiN can be obtained on EDMed surface. Moreover, TiCN can be found on cast iron and steel (S45C) by XRD investigation. To confirm the fabrication mechanisms of modified layer on the steel, the following experimental factors were investigated by EDS
Enhancing Wire-EDM Performance with Zinc-Coated Brass Wire Electrode and Ultrasonic Vibration
No full textThis study aimed to investigate the performance of zinc-coated brass wire in wire-cut electrical discharge machining (EDM) using an ultrasonic-assisted wire on tungsten carbide. The research focused on the effect of the wire electrode material on the material removal rate, surface roughness, and discharge waveform. Experimental results demonstrated that using ultrasonic vibration improved the material removal rate and reduced surface roughness compared to conventional wire-EDM. Cross-sectional SEM of the white layer and discharge waveform were investigated to explain the phenomena of ultrasonic vibration in the wire-cut EDM process
Effect of Carbon in the Dielectric Fluid and Workpieces on the Characteristics of Recast Layers Machined by Electrical Discharge Machining
No full textNPS Better predict online classroom
No full textBy 2020, Thailand and other countries around the world have experienced severe COVID-19 in almost every corner of the world, China, Japan or even the United States. Was also greatly affected as a result of this impact on teaching and learning management for students, which was originally a Face-to-face system, the teaching model has been changed to be an online classroom system such as Google classroom Zoom meeting Hangout skype etc. In order to evaluate the online teaching and learning model in the Thai education system therefore created a satisfaction evaluation form of 89 students in bachelor degree with online teaching. By using the Net Promoter Score (NPS) business recommendation method. The student group like a customers, by dividing the group of respondents according to a score of 0 to 10. Student groups were satisfied with traditional teaching and suggesting methods. This group is in the form of Promoter, representing 13.6 percent. For the group of students who are not satisfied with the online teaching style and do not recommend further This group is in the form of Detractor, representing minus 6.7 percent and the assessment of satisfied for traditional teaching score 75 percent, which is considered a very satisfactory level
Effect of Graphite Electrode to Surface’s Characteristic of EDM
No full textElectrical discharge machining process (EDM) is a process for removing material by the thermal of electrical discharge. Some of the melted and all of the evaporated material is then quenched and flushed away by dielectric liquid and the remaining melt recast on the finished surface. The recast layer is called as white layer. Beneath the recast layer, a heat affected zone is formed. The quality of an EDM product is usually evaluated in terms of its surface integrity, which is characterized by the surface roughness, existence of surface cracks and residual stresses. This paper presents a study of surface’s characteristics by EDM in de-ionized water due to decarbonisation. The machining tests were conducted on mild steel JIS grade SS400 with copper and graphite electrodes. The workpiece surfaces are analyzed by scanning electron microscope and XRD technique. The carbon transfers from graphite electrode to the white layer relating to martensitic phrase of recast layer
Comparative Fatigue Performance of Decarburized Surfaces in Railway Rails
No full textThis study explores the comparative fatigue performance of decarburized surfaces in railway components, emphasizing rolling contact fatigue, crack propagation, and acoustic emission. The investigation entails the examination of two grades of railway steels, namely R260 and U71Mn, to analyze crack and surface characteristics subsequent to fatigue testing employing a Twin Roller Machine. The purpose is to discern the impact of decarburization on the fatigue life of these materials. The results reveal distinct patterns in crack propagation and acoustic emission between decarburized and non-decarburized surfaces, providing valuable insights into the fatigue behavior of railway components. This comparative analysis contributes to a nuanced understanding of the material’s response to cyclic loading
Effect of Graphite Electrode to Surface’s Characteristic of EDM
No full textElectrical discharge machining process (EDM) is a process for removing material by the thermal of electrical discharge. Some of the melted and all of the evaporated material is then quenched and flushed away by dielectric liquid and the remaining melt recast on the finished surface. The recast layer is called as white layer. Beneath the recast layer, a heat affected zone is formed. The quality of an EDM product is usually evaluated in terms of its surface integrity, which is characterized by the surface roughness, existence of surface cracks and residual stresses. This paper presents a study of surface’s characteristics by EDM in de-ionized water due to decarbonisation. The machining tests were conducted on mild steel JIS grade SS400 with copper and graphite electrodes. The workpiece surfaces are analyzed by scanning electron microscope and XRD technique. The carbon transfers from graphite electrode to the white layer relating to martensitic phrase of recast layer
Towards Compositional Graph Theory
No full textAbstractDecomposing graphs into simpler graphs is one of the central concerns of graph theory. Investigations have revealed deep concepts such as modular decomposition, tree width or rank width, which measure—in different ways—the structural complexity of a graph's topology. Courcelle and others have shown that such concepts can be used to obtain efficient algorithms for families of graphs that are amenable to decomposition (e.g. those that have bounded tree-width). These algorithms, in turn, are of course of use in computer science, where graphs are ubiquitous. In this paper we take the first steps towards understanding notions of decomposition in graph theory compositionally, and more generally, in a categorical setting: category theory, after all, is the mathematics of compositionality.We introduce the concept of ∪–matrices (cup-matrices). Like ordinary matrices, ∪-matrices are the arrows of a PROP: we give a presentation, extending the work of Lafont, and Bonchi, Zanasi and the second author. A variant of ∪-matrices is then used in the development of a novel algebra of simple graphs, the lingua franca of graph theory. The algebra is that of a certain symmetric monoidal theory: ∪-matrices—akin to adjacency matrices—encode the graphs' topology
Author Correction: Establishment, characterization, and genetic profiling of patient-derived osteosarcoma cells from a patient with retinoblastoma
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