Browsing by Author "Kumar, A.V."

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Effect of cryogenic grinding on fatigue life of additively manufactured maraging steel
(MDPI AG, 2021) Balan, A.S.S.; Kannan, C.; Kumar, A.V.; Hariharan, H.; Pimenov, D.Y.; Giasin, K.; Nadolny, K.
Additive manufacturing (AM) is replacing conventional manufacturing techniques due to its ability to manufacture complex structures with near?net shape and reduced material wastage. However, the poor surface integrity of the AM parts deteriorates the service life of the components. The AM parts should be subjected to post?processing treatment for improving surface integrity and fatigue life. In this research, maraging steel is printed using direct metal laser sintering (DMLS) process and the influence of grinding on the fatigue life of this additively manufactured material was investigated. For this purpose, the grinding experiments were performed under two different grinding environments such as dry and cryogenic conditions using a cubic boron nitride (CBN) grinding wheel. The results revealed that surface roughness could be reduced by about 87% under cryogenic condition over dry grinding. The fatigue tests carried out on the additive manufactured materials exposed a substantial increase of about 170% in their fatigue life when subjected to cryogenic grinding. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Laser aided metal additive manufacturing and postprocessing: A comprehensive review
(Elsevier, 2021) Velu, R.; Kumar, A.V.; Balan, A.S.S.; Mazumder, J.
In the recent industrial revolution (Industry 5.0), additive manufacturing (AM) will be a very interesting technology, and it is predicted that it will have a significant impact on a wide range of industries in the near future. AM involves many different processing techniques, such as powder bed fusion, directed energy deposition (DED), sheet lamination, and so on, and it can use many different feedstock materials such as metals, polymers, and ceramics. In this chapter, we focused our attention on laser-based AM techniques used to produce metal parts, specifically in selective laser melting and laser-assisted DED techniques. The chapter begins with a classification of lasers and the interaction of lasers with materials. Furthermore, a comprehensive review on the classification of laser-based AM processes, their working principle, relevance of laser processing, need for postprocessing, and a classification of postprocessing techniques are explained in detail. Finally, it is shown that AM processes must be combined in the near future with all traditional manufacturing technologies; however, laser-based AM techniques have an excellent opportunity to influence the current manufacturing sector. © 2021 Elsevier Inc. All rights reserved.
Split personality malware detection and defeating in popular virtual machines
(2012) Kumar, A.V.; Vishnani, K.; Kumar, K.V.
Virtual Machines have gained immense popularity amongst the Security Researchers and Malware Analysts due to their pertinent design to analyze malware without risking permanent infection to the actual system carrying out the tests. This is because during analysis, even if a malware infects and destabilizes the guest OS, the analyst can simply load in a fresh image thus avoiding any damage to the actual machine. However, the cat and mouse game between the Black Hat and the White Hat Hackers is a well established fact. Hence, the malware writers have once again raised their stakes by creating a new kind of malware which can detect the presence of virtual machines. Once it detects that it is running on a virtual machine, it either terminates execution immediately or simply hides its malicious intent and continues to execute in a benign manner thus evading its own detection. This category of malware has been termed as Split Personality malware or Analysis Aware malware in the Information Security jargon. This paper aims at defeating the split personality malware in popular virtual machine environment. This work includes first the study of various virtual machine detection techniques and then development of a method to thwart these techniques from successfully detecting the virtual machines-VirtualBox, VirtualPC and VMware. Copyright � 2012 ACM.
Split personality malware detection and defeating in popular virtual machines
(2012) Kumar, A.V.; Vishnani, K.; Kumar, K.V.
Virtual Machines have gained immense popularity amongst the Security Researchers and Malware Analysts due to their pertinent design to analyze malware without risking permanent infection to the actual system carrying out the tests. This is because during analysis, even if a malware infects and destabilizes the guest OS, the analyst can simply load in a fresh image thus avoiding any damage to the actual machine. However, the cat and mouse game between the Black Hat and the White Hat Hackers is a well established fact. Hence, the malware writers have once again raised their stakes by creating a new kind of malware which can detect the presence of virtual machines. Once it detects that it is running on a virtual machine, it either terminates execution immediately or simply hides its malicious intent and continues to execute in a benign manner thus evading its own detection. This category of malware has been termed as Split Personality malware or Analysis Aware malware in the Information Security jargon. This paper aims at defeating the split personality malware in popular virtual machine environment. This work includes first the study of various virtual machine detection techniques and then development of a method to thwart these techniques from successfully detecting the virtual machines-VirtualBox, VirtualPC and VMware. Copyright Â© 2012 ACM.