Effect of moulding sand on statistically controlled hybrid rapid casting solution for zinc alloys

Rupinder Singh 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.8

The purpose of the present investigations is to study the effect of moulding sand on decreasing shell wall thickness of mould cavities for economical and statistically controlled hybrid rapid casting solutions (combination of three dimensional printing and conventional sand casting) for zinc alloys. Starting from the identification of component/ benchmark, technological prototypes were produced at different shell wall thicknesses supported by three different types of sands (namely: dry, green and molasses). Prototypes prepared by the proposed process are for assembly check purpose and not for functional validation of the parts. The study suggested that a shell wall with a less than recommended thickness (12mm) is more suitable for dimensional accuracy. The best dimensional accuracy was obtained at 3mm shell wall thickness with green sand. The process was found to be under statistical control.

Protective Effects of Caspase-9 and Poly(ADP-ribose) Polymerase Inhibitors on Ischemia-Reperfusion-Induced Myocardial Injury

Rupinder K. Sodhi,Manjeet Singh,Amteshwar S. Jaggi,Nirmal Singh 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.7

The present study was designed to investigate the cardio-protective effect of Ac-LEDH-cmk a selective caspase-9 inhibitor and 5-aminoisoquinolinone a selective Poly (ADP-ribose) polymerase inhibitor on ischemia and reperfusion induced apoptotic and necrotic cell death in rats. Isolated rat hearts were exposed to 30 minutes of global ischemia followed by 120 minutes of reperfusion using Langendorff’s apparatus. Myocardial injury was assessed in the terms of infarct size, release of lactate dehydrogenase, creatine kinase enzymes and apoptotic index was assessed by DNA smearing on agarose gel electrophoresis. Pretreatments with specific inhibitor of caspase-9, Ac-LEHD-cmk (0.07 μM and 0.105 μM), and inhibitor of PARP, 5-aminoisoquinolinone (5 μM and 7.5 μM), significantly attenuated I/R induced increase in infarct size, release of lactate dehydrogenase and creatine kinase in the coronary effluent, and apoptotic index. Therefore, it may be concluded that inhibition of caspase-9 and PARP prevent ischemia and reperfusion-induced activation of apoptotic cascade and necrosis in rat myocardium.

Effect of process parameters on surface hardness, dimensional accuracy and surface roughness of investment cast components

Rupinder Singh,Sunpreet Singh 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.1

This paper deals with investment casting (IC) application for development of spherical disc of ball valve as a case study. Three controllable factors of the IC process, namely: volume/surface-area (V/A) ratio of components, slurry layer’s combination (LC) and type of metal (MT), were studied at three levels by Taguchi’s parametric approach and single-response optimization was conducted to identify the main factors controlling surface hardness (SH), surface roughness (Ra) and dimensional accuracy (=d). Ceramic shell moulds were made on wax plate using primary slurry and fused-silica sand as stucco. Castings were produced using Al, M.S and S.S at recommended arameters by following Taguchi L9 orthogonal array through ceramic shell IC process. The microstructure analysis has been used to study the surface morphology.

Modeling of surface hardness in hot chamber die casting using Buckingham’s π approach

Rupinder Singh 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.2

Hot chamber die casting (HCDC) process is designed to achieve high dimensional accuracy and surface hardness (SH) for industrialapplications (like machine tool components). In the present study, outcome of Taguchi model has been used for developing a mathematicalmodel for SH; using Buckingham’s π-theorem for HCDC process. Three input parameters namely pressure at 2nd phase; metal pouringtemperature and die opening time were selected to give output in form of SH. This study will provide main effects of these variableson SH and will shed light on the casting hardness mechanism in HCDC process. The comparison with experimental results will alsoserve as further validation of model.

Process capability study of polyjet printing for plastic components

Rupinder Singh 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.4

The purpose of the present study is to investigate process capability of polyjet printing (PP) for plastic components. Starting from the identification of component, prototypes with three different type of plastic material were prepared at different orientations. Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the plastic components produced. Some important mechanical properties were also compared to verify the suitability of the components. Final components produced are acceptable as per ISO standard UNI EN 20286-I (1995) and DIN16901. The results of study suggest that PP process lies in ±4.5sigma (σ) limit as regard to dimensional accuracy of plastic component is concerned. This process ensures rapid production of pre-series technological prototypes and proof of concept at less production cost and time.

Investigating the effect of moulding sand properties on investment castings: a process capability study

Rupinder Singh 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.3

The purpose of the present investigation is to study the effect of molding sand properties on investment casting (IC) for process capability analysis. Starting from the identification of component/benchmark, ICs were produced with different grades of silica slurry layers (coarse, medium and fine) over the patterns (in the form of a tree). Measurements on a coordinate measuring machine (CMM) helped in calculating the dimensional tolerances of the castings produced. Some important mechanical properties were also compared to verify the suitability of the castings. The study suggested the long-term performance level of the IC process after it has been brought under statistical control as casting solution for plain carbon steel. The provided data from the experimentation highlights the ability of the IC process to produce a product that will consistently meet the design requirements and the customer expectation.

Mathematical modeling for surface hardness in investment casting applications

Rupinder Singh 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11

Investment casting (IC) has many potential engineering applications. Not much work hitherto has been reported for modeling the surface hardness (SH) in IC of industrial components. In the present study, outcome of Taguchi based macro-model has been used for developing a mathematical model for SH; using Buckingham’s π-theorem. Three input parameters namely volume/surface-area (V/A) ratio of cast components, slurry layer’s combination (LC) and molten metal pouring temperature were selected to give output in form of SH. This study will provide main effects of these variables on SH and will shed light on the SH mechanism in IC. The comparison with experimental results will also serve as further validation of model.

Realization of High Speed All-Optical Half Adder and Half Subtractor Using SOA Based Logic Gates

Simranjit Singh,Rajinder Singh Kaler,Rupinder Kaur 한국광학회 2014 Current Optics and Photonics Vol.18 No.6

In this paper, the scheme of a single module for simultaneous operation of all-optical computing circuits, namely half adder and half subtractor, are realized using semiconductor optical amplifier (SOA) based logic gates. Optical XOR gate by employing a SOA based Mach-Zehnder interferometer (MZI) configuration is used to get the sum and difference outputs. A carry signal is generated using a SOA-four wave mixing (FWM) based AND gate, whereas, the borrow is generated by employing the SOA-cross gain modulation (XGM) effect. The obtained results confirm the feasibility of our configuration by proving the good level of quality factor i.e. ~5.5, 9.95 and 12.51 for sum/difference, carry and borrow, respectively at 0 dBm of input power.

“Yellow emitting” magic-size cadmium selenide nanocrystals via a simplified spray pyrolysis method

Rupinder K. Beri,Pawan K. Khanna,Vidyanand Singh,B.R. Mehta 한국물리학회 2011 Current Applied Physics Vol.11 No.3

Magic-size nanocrystals of cadmium selenide showing yellow-light emission were synthesized in a single-step spray pyrolysis process at 150 ℃. An organoselenium precursor dissolved in N,N-dimethyl formamide was introduced via a syringe pump and the droplets were decomposed in hot solution of cadmium oleate. The ratio of Cd:Se precursor, the process temperature at which the decomposition is carried out and the co-formation of quantum dots play critical role in unique optical property of yellowlight emission.

A Case of Double Orifice Mitral Valve in a Patient with Bicuspid Aortic Valve: Coincidental or a Missed Finding?

Rupinder Buttar,Khosa Gurveer Singh,Baibhav Bipul 아시아심장혈관영상의학회 2021 Cardiovascular Imaging Asia Vol.5 No.4

A 63-year-old male with past medical history of bicuspid aortic valve and ascending aortic aneurysm was referred to cardiology for aortic valve replacement (AVR) and aneurysm repair. Transthoracic echocardiogram (TTE) showed bicuspid aortic valve with severe aortic valve stenosis. Patient underwent transesophageal echocardiogram which showed an incidental finding of double orifice mitral valve (DOMV) with fusion of A/P cusps along anterolateral commissure not noted on previous TTE. Patient underwent AVR with bioprosthetic aortic valve along with resection and replacement of the ascending aortic aneurysm. No intervention was performed for the asymptomatic DOMV. DOMV is a rare congenital cardiac abnormality, easily missed on routine TTE. It warrants need for careful evaluation of mitral valve apparatus in patients with other congenital cardiac abnormalities known to be associated with DOMV.