Prediction of weld zone shape with effect of tool pin profile in friction stir welding process

Journal of Mechanical Science and Technology - This article investigates the effect of tool pin profile on weld zone shape using computational fluid dynamics techniques in friction stir welding...     

Handling sensor faults in economic model predictive control of batch processes

The problem of sensor fault detection and isolation (FDI) and fault-tolerant economic model predictive control (FT-EMPC) for batch processes is addressed. To this end, we first model batch processes using subspace-based system identification techniques. The analytical redundancy within the identified model is subsequently exploited to detect, isolate, and handle the faulty measurements. The reconciled fault-free measurements are then incorporated in an economic model predictive controller formulation. Simulation case studies involving the application of the proposed data-driven FDI and FT-EMPC algorithms to the energy intensive electric arc furnace process illustrate the improvement in economic performance under various fault scenarios. © 2018 American Institute of Chemical Engineers AIChE J, 65: 617–628, 2019     

Determination of the fracture toughness of fabric reinforced composites by the J-integral approach

The fracture behaviour of a glass-fabric-reinforced epoxy composite has been investigated experimentally. Load-displacement curves for single-edge-notched specimens were obtained on an MTS system and the J-integral evaluated through its energy rate interpretation. J_c, the critical value of the J-integral, obtained directly for a₀/w > 0·4 and that obtained through an extrapolation procedure for a₀/w < 0·4 compare quite well. J_c appears to be independent of crack length for specimen widths between 15 and 45 mm. J_c for ±45° specimens is less than half that for 0/90 specimens.     

Machine Learning Techniques for Downscaling SMOS Satellite Soil Moisture Using MODIS Land Surface Temperature for Hydrological Application

Many hydrologic phenomena and applications such as drought, flood, irrigation management and scheduling needs high resolution satellite soil moisture data at a local/regional scale. Downscaling is a very important process to convert a coarse domain satellite data to a finer spatial resolution. Three artificial intelligence techniques along with the generalized linear model (GLM) are used to improve the spatial resolution of Soil Moisture and Ocean Salinity (SMOS) derived soil moisture, which is currently available at a very coarse scale of ~40 Km. Artificial neural network (ANN), support vector machine, relevance vector machine and generalized linear models are chosen for this study to integrate the Moderate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) with the SMOS derived soil moisture. Soil moisture deficit (SMD) derived from a hydrological model called PDM (Probability Distribution Model) is used for the downscaling performance evaluation. The statistical evaluation has also been made with the day-time and night-time MODIS LST differences with the mean day and night-time PDM SMD data for the selection of effective MODIS products. The accuracy and robustness of all the downscaling algorithms are discussed in terms of their assumptions and applicability. The statistical performance indices such as R ² , %Bias and RMSE indicates that the ANN (R ² ? =?0.751, %Bias?=??0.628 and RMSE?=?0.011), RVM (R ² ? =?0.691, %Bias?=?1.009 and RMSE?=?0.013), SVM (R ² ? =?0.698, %Bias?=?2.370 and RMSE?=?0.013) and GLM (R ² ? =?0.698, %Bias?=?1.009 and RMSE?=?0.013) algorithms on the whole are relatively more skillful to downscale the variability of the soil moisture in comparison to the non-downscaled data (R ² ? =?0.418 and RMSE?=?0.017) with the outperformance of ANN algorithm. The other attempts related to growing and non-growing seasons have been used in this study to reveal that season based downscaling is even better than continuous time series with fairly high performance statistics.     

Power Control Algorithm to Improve Coverage Probability in Heterogeneous Networks

Wireless Personal Communications -     

Fully coupled modeling and design of a piezoelectric actuation based valveless micropump for drug delivery application

The precise control over the drug delivery involved in several vital applications including healthcare is required for achieving a therapeutic effect. For such precise control/manipulation of the drugs, micropumps are used. These micropumps are basically of two types viz. check valve-based and valveless micropumps. The valveless micropumps are preferable due to the congestion-free operation of diffuser/nozzle valves. In this paper, design optimization of a valveless piezo-electric actuation based micropump is carried out using COMSOL Multiphysics 5.0 by coupling two Multiphysics interface modules namely fluid–structure interaction and piezoelectric physics modules. Using simulation studies, the influence of pump design parameters including diffuser angle, diffuser length, neck width, chamber depth, chamber diameter and diaphragm thickness on net flow rate is studied. An optimal set of design parameters for the proposed micropump is identified. Further, the influence of actuation frequency on the flow rate is analysed. It is found that the proposed micropump is capable to deliver a net flow rate of 20 µl/min and a maximum back pressure attainable is 200 Pa.

     

Design optimization of an electromagnetic actuation based valveless micropump for drug delivery application

Microsystem Technologies - A valveless micropump based on an electromagnetic actuation for drug delivery application has been designed. The parametric studies are performed to examine the effects...     

Study of Stratospheric Sudden Warming (SSW) over the tropical and subtropical regions of India using Rayleigh lidar

The Stratospheric Sudden Warming (SSW) is one of the most spectacular phenomena in the atmosphere and has impacts on the Earth’s lower, middle, and upper atmospheres. In this study, two major SSW episodes associated with vortex displacement and vortex splitting that occurred in the years 1998 and 1999, respectively, are investigated for the first time over Mt. Abu using lidar observations. Analyses show that ground-based lidar and satellite observations from the Halogen occultation experiment (HALOE) on board the upper atmospheric research satellite (UARS) can capture the effect of SSW events. Lidar measurements are able to capture SSW warming and its decay very accurately. The impact of SSW is further investigated in the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim-reanalysed potential vorticity. Moreover, a detailed study has been presented to understand the latitudinal variation of SSW warming and the associated mesospheric cooling over the Indian region. The results showed that warming is higher over the northern Indian region (35° N, 77° E) compared with the southern Indian region (5° N, 77° E).     

Co-processed κ-carrageenan-pectin as pelletizing aid for immediate-release pellets

This study investigates the extrusion-spheronization performance of some mixtures of co-processed κ-carrageenan and pectin (as excipient), and sodium starch glycolate (as superdisintegrant). Attention is focused with an objective to improve the mechanical stability and the dissolution rate of poorly soluble domperidone (as a model drug). Initially, co-processed κ-carrageenan-pectin excipient is prepared with different ratios of κ-carrageenan and pectin. Different marketed brands of κ-carrageenan (Gelcarin, Aquagel and Eugel) were employed and dried by solvent evaporation method. Further characterization was carried out by SEM, XRD and FTIR analysis. Pellets were prepared using extrusion-spheronization technique. Pellets were evaluated for flow properties, particle size, sphericity, tensile strength, friability, disintegration time and in-vitro drug release studies. Solid-state characterization of pellets was also done by FTIR, DSC and SEM analysis. The mechanical stability and dissolution rate of prepared pellets were found to be dependent on the concentration of pectin and type of κ-carrageenan employed in the fabrication of pellets. The pellets made with a high proportion of Eugel showed a very high dissolution rate of domperidone and undergo rapid disintegration validating co-processed k-carrageenan-pectin as a promising pelletizing aid for immediate-release pharmaceutical formulations.