Recent regulations for emission control from combustion engines have led to focus on various methods to monitor control and the combustion process. The presented work explores the potential relationship between various combustion events monitored using in-cylinder pressure transducer and the resulting block vibration measured using accelerometers. Various features of combustion development process were derived from the vibration data acquired. The methodology was analyzed using a single cylinder diesel engine. The heat release data was able to detect and extracted various indicators of the combustion process like start of combustion and half of injected fuel positions. Higher correlation was observed for the data computed using heat release curve obtained from the in-cylinder pressure measurements and those obtained using the accelerometer signals. The proposed methodology can be used to optimize the fuel injection timing in order to reduce emissions from engines to comply with various regulations. The practical importance of presented work demonstrates use of monitoring of block vibration signals as a mean of non-intrusive methods of diagnosis of engine for its effective condition monitoring.
A new miniature deep UV absorbance detector has been developed using low-cost and high-performance LEDs, which can be operated in both scanning (230 to 300 nm) and individual wavelength (240, 255, and 275 nm) detection modes. The detector is mostly composed of off-the-shelf components, such as LEDs, trifurcated fiber optic assembly, a capillary Z-type flow cell, and photodiodes. It has been characterized for use with a standard capillary LC system and was benchmarked against a standard variable wavelength capillary LC detector. The detector shows very low levels of stray light (<0.4%), utilization of up to 99.0% of the effective path length of the flow cell, a wide dynamic range (0.5 to 200 μg/mL for sulfamethazine, carbamazepine, and flavone), and low noise levels (at 300 μAU level). The detector was applied within a miniaturized LC system.
Per-and polyfluoroalkyl substances (PFASs) are emerging environmental pollutants of global concern. For rapid field site evaluation, there are very few sensitive, field-deployable analytical techniques. In this work, a portable lightweight capillary liquid chromatography (capLC) system was coupled with a small footprint portable mass spectrometer and configured for fieldbased applications. Further, an at-site ultrasound-assisted extraction (pUAE) methodology was developed and applied with a portable capLC/mass spectrometry (MS) system for on-site analysis of PFASs in real soil samples. The influential variables on the integration of capLC with MS and on the resolution and signal intensity of the capLC/MS setup were investigated. The important parameters affecting the efficiency of the pUAE method were also studied and optimized using the response surface methodology based on a central composite design. The mean recovery for 11 PFASs ranged between 70 and 110%, with relative standard deviations ranging from 3 to 12%. In-field method sensitivity for 12 PFASs ranged from 0.6 to 0.1 ng/g, with wide dynamic ranges (1−600 ng/g) and excellent linearities (R 2 > 0.991). The in-field portable system was benchmarked against a commercial lab-based LC−tandem MS (MS/MS) system for the analysis of PFASs in real soil samples, with the results showing good agreement. When deployed to a field site, 12 PFASs were detected and identified in real soil samples at concentrations ranging from 8.1 ng/g (for perfluorooctanesulfonic acid) to 2935.0 ng/g (perfluorohexanesulfonic acid).
Erosion of refractory lining due to flow induced wall shear stress is one among severe problems that shop floor personnel face in continuous casting tundish operation. It decreases the lining life and increases overall operational cost. Wall shear stress due to turbulent flow is one of the major factors of erosion of lining in tundish. Inclusion generation due to erosion creates surface defects that may lead to the rejection of the final products. Turbulent inhibitor box (TIB) helps in reducing the wall shear stress by confining the turbulent flow zone and hence changes the flow pattern. In the present work, three-dimensional fluid flow study has been carried out to investigate the flow induced wall shear stress. High shear stress zones (HSSZ) are taken as potential inclusion generation sites. Different sizes of inclusions are injected from those sites and their paths are tracked. It is found that the shape of TIB significantly affects the flow induced wall shear stress and inclusion removal rate. Results indicate that tundish with TIB 3 arrangement exhibited minimum wall shear stress at all walls. TIB 2 coupled tundish gives the highest removal rate in case of bottom wall originated small size inclusions (<= 80 μm) and least removal rate in case of curve wall originated inclusions.
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