KRISHNAYAN HALDAR
Verified @gmail.com
Scopus Publications
- Corrigendum to:“Evaluation of Mechanical Properties of TiO2-free Tablet Coatings”(Journal of Pharmaceutical Sciences, (2025), 114, 10, (103942), (S002235492500396X), 10.1016/j.xphs.2025.103942)
Mohammad Khalid, Viplav K. Bhondekar, Krishnayan Haldar, Mahesh S. Tirumkudulu, Kenneth S. Ogueri, Alfred Berchielli, Geoff McKee, Pankaj Doshi
Journal of Pharmaceutical Sciences, 2025 - Evaluation of mechanical properties of TiO2-free tablet coatings
Mohammad Khalid, Viplav K. Bhondekar, Krishnayan Haldar, Mahesh S. Tirumkudulu, Kenneth S. Ogueri, Alfred Berchielli, Geoff McKee, Pankaj Doshi
Journal of Pharmaceutical Sciences, 2025 - Effect of microstructure on cracking of films cast on soft substrates
Krishnayan Haldar, Mohammad Khalid, Mahesh S. Tirumkudulu
Journal of Coatings Technology and Research, 2025 - Experimental Evaluation of the Impact of Rapid Environmental Changes on Stress Distribution in Tablet Coatings
Krishnayan Haldar, Mahesh S. Tirumkudulu, Ashwin Jain, Daniel O. Blackwood, Alfred Berchielli, Pankaj Doshi
AAPS Pharmscitech, 2023
Drying-induced cracks in tablet coatings are undesirable as they not only affect tablet's appearance, but they may also interfere with its function. While it is well known that tensile stresses in the coating are responsible for coating failures, few have measured the stress in tablet coatings, especially when exposed to rapid environmental changes. In this study, two commercial tablet coatings based on Hydroxy Propyl Methyl Cellulose (HPMC) and Poly Vinyl Alcohol (PVA) are exposed to rapid variations in temperature and humidity to observe the variation in residual stress. Reducing temperature at a fixed humidity or reducing humidity at fixed temperature, both lead to high residual stresses. When both the humidity and temperature were reduced together, the residual stresses were very high causing delamination in the PVA-based film and cracking in the HPMC-based film. The changes in residual stress are almost instantaneous for the HPMC-based film while it is slower for the PVA-based film. The results highlight the importance of environmental conditions on the residual stress in the film and the resulting coating failure. - Thermo-hydrodynamic analysis of drop impact calcium alginate gelation process
Krishnayan Haldar, Sudipto Chakraborty
European Journal of Mechanics B Fluids, 2021 - Investigation of chemical reaction during sodium alginate drop impact on calcium chloride film
Krishnayan Haldar, Sudipto Chakraborty
Physics of Fluids, 2019
The objective of this work is to study the chemical reaction between sodium alginate drop and calcium chloride film and instantaneous formation of calcium alginate gel. The complexity of this work is the simultaneous effect of both liquid and solid surface on drop impact gelation process. The sodium alginate concentration in the drop fluid, liquid film thickness, and drop impingement height are varied and the observations are captured using a high speed camera. Several interesting phenomena like splashing and jet break up occur depending on the drop impingement velocity, drop concentration, and film thickness. Crosslinking reaction and mixing mechanisms are schematically explained accounting the role of capillary wave propagation within the liquid film. A mathematical model on drop spreading on the solid surface after penetrating the liquid film is developed to predict the theoretical gel length for ultrathin and thin film regimes. Maximum spreading diameter of the drop postimpact on the liquid film is predicted from the model. However, the experimentally measured solidified gel length deviates from the theoretical values and these deviations are utilized to measure the rate of crosslinking gelation and instantaneous solidification. Different hydrodynamic parameters such as the crater depth, crater contact time, and crater dissipation energy are evaluated for the dynamics of gelation. Finally, the kinetics of gelation with the variation of liquid film thickness are determined for alginate drop concentrations and drop impingement heights. - Influence of Marangoni stress on the variation in number of coalescence cascade stages
Krishnayan Haldar, Samarshi Chakraborty, Sudipto Chakraborty
Canadian Journal of Chemical Engineering, 2019
Abstract The present work is an experimental and theoretical study on surfactant‐laden liquid drop impact on a liquid pool. When the drop breaks into a secondary droplet after impinging, then it is called partial coalescence. If this happens successively in self‐similar manner then it is called coalescence cascade. Three different types of surfactants, cationic, anionic, and non‐ionic, are used as drop fluid and water as the liquid pool. Here we report how the surfactant types and concentrations affect the number of stages in coalescence cascade. The experimental outcome revealed that the number of stages in cascade decreases with increasing surfactant concentration. Also, we determine that drop viscosity, density, and size play a crucial role while comparing the stages of cascade among three types of surfactants. We also perform scaling analysis to determine the contribution of inertial and surface forces in the cascade. A theoretical analysis using lubrication approximation has also been carried out to justify the experimental observations. The coalescence process is actually triggered by the drainage of entrapped air between the drop and pool. The theoretical analysis reveals that the faster air drainage rate and acceleration induces a strong Marangoni stress for necking and quick pinch off. Finally, it is shown that Marangoni flow, originated due to the surface tension difference between the drop and pool, is responsible for partial coalescence and a number of coalescence stages in cascade. - Role of chemical reaction and drag force during drop impact gelation process
Krishnayan Haldar, Sudipto Chakraborty
Colloids and Surfaces A Physicochemical and Engineering Aspects, 2018 - Effect of liquid pool concentration on chemically reactive drop impact gelation process
Krishnayan Haldar, Sudipto Chakraborty
Journal of Colloid and Interface Science, 2018 - Heat Transfer from a Hot Moving Steel Plate by Air-Atomized Spray Impingement
J. M. Jha, S. V. Ravikumar, K. Haldar, I. Sarkar, S. K. Pal, S. Chakraborty
Experimental Heat Transfer, 2016
Air-atomized spray cooling of a hot moving AISI 304 steel plate of 6 mm thickness has been investigated experimentally by varying water flow rate and plate velocity at a fixed nozzle-to-plate distance. It is found that the heat transfer coefficient is a non-linear function of surface temperature. The result shows that the cooling rate increases with an increase in the water flow rate. The highest cooling rate has been found for the static plate, whereas for a moving plate, an increasing cooling rate trend has been observed with increasing plate velocity. - Heat transfer enhancement using air-atomized spray cooling with water-Al2O3 nanofluid
Satya V. Ravikumar, Krishnayan Haldar, Jay M. Jha, Samarshi Chakraborty, Ishita Sarkar, Surjya K. Pal, Sudipto Chakraborty
International Journal of Thermal Sciences, 2015 - Surfactant-based Cu-water nanofluid spray for heat transfer enhancement of high temperature steel surface
Satya V. Ravikumar, Jay M. Jha, Krishnayan Haldar, Surjya K. Pal, Sudipto Chakraborty
Journal of Heat Transfer, 2015 - Synthesis of Cu-Al layered double hydroxide nanofluid and characterization of its thermal properties
Samarshi Chakraborty, Ishita Sarkar, Krishnayan Haldar, Surjya Kanta Pal, Sudipto Chakraborty
Applied Clay Science, 2015
