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Springback Reduction by Using Tool Rollers
Chetan P. Nikhare 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.1
Springback is defined as a geometric defect, which occurs due to elastic recovery in the part after it has been unloaded. This challenge is most common in lightweight alloys as well as in advanced high strength steels. The materials, which exhibit lower elastic modulus or higher tensile strength, would be more prone to springback. In this paper, a novel patented technique is introduced to eliminate the springback by using rollers in the forming tool. It was found that due to the rotation of rollers in the tool during forming, reduces the stress in the part and, thus reduces the springback.
Chetan Kapoor,Troy L. Graves-Abe,Jin-Song Pei 국제구조공학회 2007 Smart Structures and Systems, An International Jou Vol.3 No.1
In this study, Field-Programmable Gate Arrays (FPGAs) are investigated as a practical solution to the challenge of designing an optimal platform for implementing algorithms in a wireless sensing unit for structural health monitoring. Inherent advantages, such as tremendous processing power, coupled with reconfigurable and flexible architecture render FPGAs a prime candidate for the processing core in an optimal wireless sensor unit, especially when handling Digital Signal Processing (DSP) and system identification algorithms. This paper presents an effort to create a proof-of-concept unit, wherein an off-the-shelf FPGA development board, available at a price comparable to a microprocessor development board, was adopted. Data processing functions, including windowing, Fast Fourier Transform (FFT), and peak detection, were implemented in the FPGA using a Matlab Simulink-based high-level abstraction tool rather than hardware descriptive language. Simulations and laboratory tests were carried out to validate the design.
( Chetan Rathi ),( Nirav Pipaliya ),( Prateik Poddar ),( Vikas Pandey ),( Meghraj Ingle ),( Prabha Sawant ) 대한장연구학회 2015 Intestinal Research Vol.13 No.4
Pneumatosis intestinalis is a rare condition that affects 0.03% of the population. Pneumatosis cystoides intestinalis (PCI) is characterized by the presence of multiple gas-filled cysts in the intestinal wall and the submucosa and/or intestinal subserosa. It is usually a secondary finding caused by a wide variety of underlying gastrointestinal or extragastrointestinal diseases. Here, we present the case of a 47-year-old man who was referred to our gastroenterology department with a history suggestive of intermittent small bowel obstruction associated with abdominal pain. Abdominal computed tomography demonstrated PCI of the small bowel. The mesentery and branches of the superior mesenteric artery and superior mesenteric vein were twisted with minimal pneumoperitoneum. Exploratory laparotomy was performed, and demonstrated segmental small bowel PCI secondary to hypermobile mesentery. The affected segment of the ileum was resected, and jejunoileal anastomosis was performed. Here, we report a rare case of segmental PCI probably due to repeated twisting of hypermobile mesentery. The clinical and imaging features of this disorder may mimic those of visceral perforation or bowel ischemia. PCI can be a cause of severe abdominal pain that may require surgical intervention. (Intest Res 2015;13:346-349)
Chetan Joshi,Rekha Satishchandra Singhal 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.1
The operational optimization of zeaxanthin production by Paracoccus zeaxanthinifaciens ATCC 21588 in a bubble column reactor was performed by coupling genetic algorithm (GA) to an artificial neural network (ANN) model developed using experimental one-variable-at-a-time (OVAT) results. The effects of varying air flow rate (2- 5 vvm) and inoculum size (4 and 8%) for different incubation time (30-80 h) were evaluated. Volumetric power input (P/VL) and energy input (E) to the bubble column were then correlated with the ANN-GA optimized conditions. A maximum zeaxanthin production of 13.76±0.14mg/L was observed at 4 vvm using an inoculum size of 4% (v/v) after 60h of incubation in OVAT experiments with corresponding P/VL value of 231.57 W/m3 reflecting an energy consumption of 50.02 kJ during the fermentation period. The ANN based GA optimization predicted a maximum zeaxanthin production of 14.79mg/L at 3.507 vvm, 4% inoculum size and 55.83 h against the experimental production of 15.09±0.51mg/L corresponding to a P/VL value of 202.03 W/m3 reflecting to a significantly reduced energy input (40.01 kJ). The proposed OVAT based ANN-GA optimization approach can be used to simulate similar studies involving microbial fermentation in bioreactors.
Conceptualizing educational leadership: does exploring macro-level facets matters?
Chetan Sinha 서울대학교 교육연구소 2013 Asia Pacific Education Review Vol.14 No.2
The present review attempts to examine the present status of educational leadership highlighting the role of macro-level facets in Asian Pacific context. The conceptualization of educational leadership among researchers so far had been found to vary according to different contexts and situations. Theoretical perspectives associated with educational leadership have either approached the concept from dimensions working outside the school or from dimensions reflecting the personality trait of the principal. There is an urgent need to shift the focus of attention toward understanding educational leadership through an interactive collaboration of these dimensions. Specifically, in school contexts, the phenomenon of educational leadership was explored and theorized from one perspective only, giving less space to have multidisciplinary view, which need to be revived in terms of contexts and associated metaphors of educational leadership. Although the importance of educational leadership has been widely acknowledged, its role still remains unheeded in various sections of education. The purpose of the review, thus, is to gain macro-level insight into this concept which can hopefully answer many aspects of education which are otherwise left unanswered, thereby helping in formulating better educational reforms.
Chetan M. Patel,Mousumi Chakraborty,Z.V.P. Murthy 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.4
A systematic study on wet grinding of barium sulfate to produce nanoparticles (<50 nm) was performed in a stirred media mill. The suspension stabilization by pH adjustment and dispersants addition were investigated using zeta potential measurement and the multiple light scattering methods. It was found that particle size reduction requires use of dispersant (sodium salt of polyacrylic acid). The optimum amount of dispersant concentration was determined to be 2% by weight. Further, the influence of pinlength was found to improve the performance. The influence of solids mass fraction, grinding media diameter on pH variation and final size were evaluated.