Few research results

• Vamsi Krishna, Sonu Kumar, K. Anki Reddy, Granular particle-shape heterogeneous mixtures discharging through a silo, Journal of Fluid Mechanics, 2021, vol.912, A22.

Context and description:  Process industries often involve handling non-cohesive solid materials which vary in size and shape. A comprehensive understanding of such systems helps in effective handling of industrial operations.  In this context, we studied heterogeneous mixtures of dumbbells and discs flowing out of a two-dimensional silo via discrete element method simulations. We analysed discharge dynamics of the mixtures in two regimes, namely the free-flow regime (W/d >= 15) and the interrupted flow regime (W/d <= 10), where W and d are the orifice width and diameter of each of the circles of a dumbbell. One of the intriguing results is a decrease in the flow rate Q of mixtures with an increase in the fraction of dumbbells Xdb in both of the regimes analysed. This can be attributed to the geometrical interlocking among the particles and a hindrance to the rotation of dumbbells. The time-averaged (coarse-grained) flow fields reveal an increase in the size of the stagnant zone beside the orifice with an increase in Xdb. The stagnant zone hinders the particles flowing next to it, which is another reason for a decrease in Q with an increase in Xdb. In the interrupted flow regime, we investigated clogged states of the mixtures using arch morphology, the fraction of dumbbells and number of particles in an arch, and avalanche sizes.

• Shivam Tiwari, Vasista Adupa, Dhanesh Das, K. Anki Reddy, T. V. Bharat, Structural and dynamic insights into SARS-CoV-2 spike protein – Montmorillonite interactions, Langmuir, 2022, 38, 9186-9194.

Context and description: The spike (S) protein of SARS-CoV-2 has been found to play a decisive role in the cell entry mechanism of the virus and has been the prime target of most vaccine development efforts. Although numerous vaccines are already in use and more than half of the world population has been fully vaccinated, the emergence of new variants of the virus poses a challenge to the existing vaccines. Hence, developing an effective drug therapy is a crucial step in ending the pandemic. Nanoparticles can play a crucial role as a drug or a drug carrier and help tackle the pandemic effectively. Here, we performed explicit all-atom molecular dynamics simulations to probe interactions between S protein

and Montmorillonite (MMT) nano clay surface. We considered two systems with different counterions (Na+ and Ca2+), namely Na-MMT and Ca-MMT, to investigate the effect of different ions on S protein-MMT interaction. Structural modification of S protein was observed in the presence of MMT surface, particularly the loss of helical content of S protein. We revealed that electrostatic and hydrophobic interactions synergistically govern the S protein-MMT interactions. However, hydrophobic interactions were more pronounced in the Na-MMT system than in Ca-MMT. We also revealed residues and glycans of S protein closely interacting with the MMT surface. Interestingly, N165 and N343, which we found to be closely interacting with MMT in our simulations, also have a critical role in cell entry and in thwarting the cell’s immune response in recent studies. Overall, our work provides atomistic insights into S protein-MMT interaction and enriches our understanding of the nanoparticle-S protein interaction mechanism, which will help develop advanced therapeutic techniques in the future.

• Rajasekhar, A. Gogoi, K. Anki Reddy, Cationic stabilised layered graphene oxide (GO) membrane for shale gas wastewater treatment: An atomistic insight, 2023, Desalination, 559, 116621.

Context and description:   In recent years graphene oxide (GO) membranes have emerged as one of the most promising candidates for wastewater treatment. However, one major issue with layered GO membranes is their tendency to swell in an aqueous environment. Cation intercalation inside the interlayer gallery of layered GO membrane is one of the promising solutions to mitigate this problem. However, the effect of cationic concentration inside membrane channels on the mechanism of water permeance and salt rejection is yet to be investigated in detail. This study investigates shale gas wastewater (NaCl, CaCl₂, and crude oil) treatment via nonequilibrium molecular dynamics (MD) simulations with cation (K⁺, Mg²⁺) intercalated GO membranes. The effect of cationic concentration on water permeance and salt rejection has been presented in detail. This study reveals that the presence of a higher concentration of cations inside the GO membrane induces higher water resistance in the membrane. In addition to the concentration of intercalated ions, interlayer distance also plays a significant role in determining water permeance. We observed that Mg²⁺ ion intercalated and K+ ion intercalated GO membranes maintain an interlayer distance of around 13.6 Å and 11.4 Å, respectively. As a result, Mg²⁺ ion intercalated GO membranes exhibit superior water permeance than K+ ion intercalated GO membranes. We also observed a difference in the crude oil aggregate formation (a composition of alkanes, cycloalkanes, and aromatics) in the two systems (more stable aggregate in K+ ion intercalated GO membrane system as compared to Mg2+ ion intercalated GO membrane system) during the forward osmosis (FO) process. This can be attributed to weaker interactions of K+ ions with the crude oil and lower water permeance of K+ ion intercalated GO membranes than Mg2+ ion intercalated GO membranes. This aggregate formation is an important factor for crude oil rejection. Moreover, aromatics are more concentrated at the crude oil-water interface than other hydrocarbons. On the other hand, more cations inside the GO membrane layers results in better Na⁺ rejection but decreased Cl^- rejection.

Energy and Environmental Sciences

1. Moon, K. Anki Reddy, S. Pandian, K. S. Mayya and S. Han, Polyamide-POSS hybrid membranes for seawater desalination: effect of POSS on membrane properties, 2014, Journal of Membrane Science, 461 : 89-95.
2. Shanthi Pandian, Anki Reddy, Jun Hyuk Moon, Subramanya Mayya Kolake and Sungsoo Han, Exploring the effect of additives on polyamide membrane surface for seawater desalination using density functional tools, 2015, Desalination, 367: 28-36.
3. Ashim Malakar, Manishekhar Kumar, Anki Reddy, Himadree T. Biswal, Biman B. Mandal andG. Krishnamoorthy, Aggregation induced enhanced emission of 2-(2’-hydroxyphenyl)benzimidazole, 2016,Photochemical and Photobiological Sciences, 15 : 937-948.
4. Subrata Nath, Suraj Kumar Pathak, Balaram Pradhan,  Ravindra Kumar Gupta,  Anki Reddy, G. Krishnamoorthy and Ammathnadu S. Achalkumar, A sensitive and selective sensor for picric acid detection with a fluorescence switching response, 2018, New Journal of Chemistry, 42 : 5382-5394.
5. Abhijit Gogoi, Tukhar Jyoti Konch, Kalyan Raidongia, Anki Reddy, Water and salt dynamics in multilayer graphene oxide (GO) membrane: role of lateral sheet dimensions, 2018, Journal of Membrane Science, 563 : 785.
6. Tukhar Jyoti Konch, Raj Kumar Gogoi, Abhijit Gogoi, Kundan Saha, Jumi Deka, K. Anki Reddy, Kalyan Raidongia,Nanofluidic transport through humic acid modified graphene oxide nanochannels, 2018, Materials Chemistry Frontiers, 2 :
7. Abhijit Gogoi, Anki Reddy, Pranab Mondal, Multilayer Graphene Oxide Membrane in Forward Osmosis: Molecular Insights, 2018, ACS Applied Nano Materials, 1 : 4450.
8. Anindya Patra, Manendra Chauhan, Sam Keene, Gaurangi Gogoi, Anki Reddy, Shane Ardo, Dasari Prasad and Mohammad Qureshi, New Insights into the Synergistic Effects of Cerium Doping, Oxygen Vacancies, and Structural Distortions in Photocatalytic Hydrogen Production Efficiency of BaZrO3-δ Hollow Nanospheres: A Combined Experimental and Theoretical Study, 2019, Journal of Physical Chemistry C, 123(1):233.
9. Abhijit Gogoi, Aditya Koneru and K. Anki Reddy, Effect of graphene oxide (GO) nanosheet sizes, pinhole defects and non-ideal lamellar stacking on the performance of layered GO membranes: an atomistic investigation, 2019, Nanoscale Advances , 1:
10. Shivam Tiwari, Abhijit Gogoi and Anki Reddy , What Governs the Nature of Fouling in For- ward Osmosis (FO) and Reverse Osmosis (RO) ? A Molecular Dynamics Study, 2019, Physical Chemistry Chemical Physics, 21: 24165.
11. Ila Verma, Ashim Malakar, Abhijit Gogoi, Anki Reddy,  Manishekhar Kumar,  Biman Mandal and G. Krishnamoorthy, Pyridyl Substitution Control Dynamics and Shape Dependence of Fluorescent Aggregates, 2020, Journal of Photochemistry and Photobiology A: Chemistry, 392, 112405.
12. Abhijit Gogoi, K. Anki Reddy and Pranab Kumar Mondal, Influence of the Presence of the Cations on the Water and Salt Dynamics Inside Layered Graphene Oxide (GO) Membranes, 2020, Nanoscale, 12,
13. Kranthi Kumar Munubarthi, Dinesh Kumar Gautam, Anki Reddy, Senthilmurugan Subbiah, Distributed parameter system modeling approach for the characterization of a high flux hollow fiber forward osmosis (HFFO) membrane, 2020, Desalination, 496, 114706.
14. Abhijit Gogoi, K. Anki Reddy, S. Senthilmurugan, Pranab Kumar Mondal, Dehydration of Acetic Acid using Layered Graphene Oxide (GO) Membrane through Forward Osmosis (FO) Process: A Molecular Dynamics Study, 2020 Molecular Simulation.
15. Vinod Kumar Vishwakarma, Vasista Adupa, K. Anki Reddy and Achalkumar, Experimental and Theoretical Investigations of acid sensing properties of Pyrazino[2,3-g]quinoxaline Derivatives, 2021, Journal of Molecular Structure, 1225,
16. Bhanupriya Das, Surendra Singh Gaur, Anki Reddy, Chin Tsan Wang and Vimal Katiyar, Crosslinked Poly(vinyl alcohol) Membrane as Separator for Domestic Wastewater Fed Dual Cham- bered Microbial Fuel Cells, 2021, International Journal of Hydrogen Energy, 46, 7073.
17. Shivam Tiwari, Abhijit Gogoi and K. Anki Reddy, Effect of Ionic Environment on Membrane Fouling: A Molecular Dynamics Study, 2021, Physical Chemistry Chemical Physics, 23, 5001.
18. Anirban Sikdar, Abhisek Majumdar, Abhijit Gogoi, Pronoy Dutta, Munu Borah, Soumen Maiti, K. Anki Reddy, Youngtak Oh, Uday Narayan Maiti, Diffusion driven nanostructuring of metal-organic frameworks (MOFs) for graphene hydrogel based tunable heterostructures: Highly active electrocata- lyst for efficient water oxidation, 2021, Journal of Materials Chemistry A, 9, 7640.
19. Sikdar Anirban, Deb Sujit, Gogoi Abhijit, Majumdar Abhisek, Dutta Pronoy, K. Anki Reddy and Maiti Uday, Polyaniline - Graphene Hydrogel Hybrids via Diffusion Controlled Surface Polymerization for High Performance Supercapacitors, 2020, ACS Applied Nanomaterials, 3, 12, 12278.
20. Rajasekhar, Abhijit Gogoi and K. Anki Reddy, The effect of oxygen functional groups on removal of Amoxicillin and the performance of graphene Oxide (GO) membrane in forward osmosis (FO): A molecular dynamics study, 2022, Molecular Simulation, 48, 185.
21. Bhanupriya Das, Soundararajan Narendren, Sourav Pratim Kashyap, Jer-Huan Jang, Chin Tsan Wang, K. Anki Reddy and Vimal Katiyar, Bioaugmented Polyaniline decorated Polylactic acid nanofiber electrode by electrospinning technique for real wastewater-fed  MFC application , 2022, International Journal of Energy    Research,  46,  3588.
22. Pulak Sarkar, Solagna Modak, Santanu Ray, Adupa Vasista, K. Anki Reddy and Santanu Karan, Fast Water Transport Through Sub-5 nm Polyamide Nanofilms: The New Upper-Bound of the Permeance-Selectivity Trade-Off in Nanofiltration. Journal of Materials Chemistry A, 9, 20714.
23. Karishma Tiwari, Solagna Modak, Pulak Sarkar, Santanu Ray, Adupa Vasista, K. Anki Reddy, Sumit Kumar Pramanik, Amitava Das and Santanu Karan, Interfacial synthesis of large-area ultrathin polyimine nanofilms as molecular separation membrane, 2022, IScience, 25, 104027.
24. Debarati Mukherjee, Pradid Das, Nagendra Prasad, K. Anki Reddy, S. Gumma and Bishnupada Mandal, Hierarchical Graphite Oxide Decorated UiO-66 for Ultrahigh Adsorption of Dye with Synergistic Effect of Ultrasonication: Experimental and Density Functional Theory Study, 2022, Separation and Purification Technology, 2022, 294,121217.
25. Rajasekhar, Abhijit Gogoi and K. Anki Reddy, Cationic stabilized layered graphene oxide (GO) membrane for shale gas wastewater treatment: An atomistic insight, 2023, Desalination, 559,116621.
26. Nagendra Prasad, Adupa Vasista, K. Anki Reddy, Chandan Das, and Santanu Karan, Semi-aromatic polyamide based membrane in forward osmosis: Molecular insights, 2023, Journal of Physical Chemistry B, 2023, 127, 30, 6751-6766.
27. Rajasekhar, K. Anki Reddy and Amit Kumar, Understanding the boron rejection of cation interacted multilayered graphene oxide (GO) membrane in reverse osmosis (RO) process: A molecular dynamics study, Journal of Molecular Liquids, 2023.
28. Shabnam Pathan, Sk Safikul Islam, Ria Sen Gupta, Barnali Maity, P Rajasekhar Reddy, Samir Mandal, K Anki Reddy, Suryasarathi Bose, Fundamental Understanding of Ultrathin, Highly Stable Self-Assembled Liquid Crystalline Graphene Oxide Membranes Leading to Precise Molecular Sieving through Non-equilibrium Molecular Dynamics, ACS Nano 2023, 17,8,7272-7284.
29. Bhanupriya Das, Surendra Singh Gaur, Anki Reddy Katha, Chin Tsan Wang, Vimal Katiyar, Hair hydrolysate functionalized cellulose nanocrystal based chitosan membrane to harness power from wastewater fed MFCs, International Journal of Hydrogen Energy, 2023, 48,25,9451-9461.
30. Sk Safikul Islam , Anjali Kumari, Arya S, , Shabnam Pathana, , P. Rajasekhar Reddy,  Ria Sen Gupta, , K. Anki Reddy , and Suryasarathi Bose, Can the stacking periodicity in graphene oxide liquid crystal membranes be controlled by careful selection of solvent and functional motif for precise molecular sieving
31. Rajasekhar, K. Anki Reddy and Amit Kumar, Ion dynamics in Lamellar and non-lamellar cation intercalated GO membranes via atomistic simulations, 2023.
32. Pulak Sarkar, Gunolla Nagendraprasad, K. Anki Reddy and Santanu Karan, Elucidating solvent activation and transport in polyamide membranes via experimental and molecular dynamics simulation studies, 2023.

Computational Biophysics

33. Ramachandran, K. Anki Reddy K. S. Mayya, B. Jung and S. Han, Dynamics of dilute solutions of poly(aspartic acid) and its sodium salt elucidated from molecular dynamics simulations with explicit water, 2013, Journal of Physical Chemistry B, 117 : 13906.
34. Cade B. Markegard, Iris W. Fu, K. Anki Reddy, and Hung D. Nguyen,Coarse-Grained Simulation Study of Sequence Effects on DNA Hybridization in a Concentrated Environment, 2015, Journal of Physical Chemistry B, 119 : 1823.
35. Abhishek Roy, Shivam Tiwari, Srijeeb Karmakar, K. Anki Reddy, Lalit M. Pandey, The effect of stoichiometric ratio of Zinc towards the fibrillation of Bovine Serum Albumin (BSA): A mechanistic insight, 2018, International Journal of Biological Macromolecules, 123 : 409. URL :
36. Adupa Vasista, B. Mandal and K. Anki Reddy, Pro-drug peptide and its metabolites disrupt amyloid fibrils by destabilizing salt bridge interaction and planar beta-sheet topology, 2020, bioRxiv,2020.09.09.290643.
37. Shivam Tiwari, Adupa Vasista, Dhanesh Das, K. Anki Reddy and Tadikonda Bharat, Structural and dynamic insights into SARS-CoV-2 Spike protein – Montmorillonite interactions, 2022, Langmuir, 38,30,9186-9194.
38. Shivam Tiwari, B. Mandal and K. Anki Reddy, The Role of Binding Site Specificity in the Disaggregation of Abeta Fibrils through a Synthetic Paratope, 2023, bioRxiv.

Fluid Dynamics and Suspensions

39. Manish Dhiman, Suru Aditya Ashutosh, Raghvendra Gupta and K. Anki Reddy, Drag on Sticky and Janus Spheres Confined in a Channel, 2020, ASME Journal of Fluids Engineering,142(7): 071303.
40. Sudarshan Konidena, Jonghoon Lee, K. Anki Reddy, Anugrah Singh, Particle dynamics and pattern formation in a rotating suspension of positively buoyant particles, 2018,Physical Review Fluids, 3 : 044301.
41. Sudarshan Konidena, K. Anki Reddy and Anugrah Singh, Dynamics of bi-density particle suspension in horizontal rotating cylinder, 2019, Physical Review E, 99:013111.
42. Manish Dhiman, Raghvendra Gupta and K. Anki Reddy, Drag on Janus Sphere in a Channel: Effect of Particle Position, 2021, ASME Journal of Fluids Engineering, 143(3): 031302
43. Abhijit Gogoi, K. Anki Reddy and Pranab Kumar Mondal, Electroosmotic flow through nanochan- nel with patterned surface charge distribution: A molecular dynamics study, 2021. Physics of Fluids,33, 092115.
44. Manish Dhiman, Raghvendra Gupta and K. Anki Reddy, Hydrodynamic Interactions between two side-by-side Janus spheres, 2021, European Journal of Mechanics/B Fluids, 87, 61.
45. Manish Dhiman, Raghvendra Gupta and K. Anki Reddy, Lift on Stick and Janus spheres in a channel, 2021, Theoretical and Computational Fluid Dynamics, 35, 659.
46. Sudarshan Konidena, Shadab Mohammed, K. Anki Reddy and Anugrah Singh, Influence of normal stresses on axial patterns in horizontal rotating cylinders, (Under review)
47. Manish Dhiman, Raghvendra Gupta, K. Anki Reddy, Numerical investigation on the flow past a single, and in-line Janus cylinders in a planar flow, 2023.

Granular Physics

48. Anki Reddy and V. Kumaran, Applicability of constitutive relations from kinetic theory for dense granular flows, 2007, Physical Review E, 76 : 061305.
49. Orpe, V. Kumaran, K. Anki Reddy and Arshad Kudrolli, Fast decay of the velocity autocorrelation function in dense shear flow of inelastic hard spheres, 2008, Euro Physics Letters, 84 : 64003.
50. Anki Reddy and V. Kumaran, Structure and dynamics of two-dimensional sheared granular flows, 2009, Physical Review E, 79 : 061303.
51. Anki Reddy, V. Kumaran and J. Talbot, Orientational ordering in sheared inelastic dumbbells,2009, Physical Review E 80 : 031304.
52. Anki Reddy, J. Talbot and V. Kumaran, Dynamics of sheared inelastic dumbbells, 2010, Journal of Fluid Mechanics, 660 : 475-498.
53. Anki Reddy and V. Kumaran, Dense granular flow down an inclined plane: A comparison between the hard particle model and soft particle simulations, 2010, Physics of Fluids, 22 : 113302.
54. Anki Reddy, Yoel Forterre and O. Pouliquen, Evidence of mechanically activated processes in slow granular flows, 2011, Physical Review Letters, 106 : 108301.
55. Andreea Panaitescu, K. Anki Reddy and A. Kudrolli,Nucleation and crystal growth in sheared granular sphere packings, 2012, Physical Review Letters, 108 : 108001.
56. Endo, K. Anki Reddy, H. Katsuragi, Obstacle-shape effect in a two-dimensional granular silo flow field, 2017, Physical Review Fluids, 2 : 094302.
57. H Katsuragi, K Anki Reddy, K Endo, Shape dependence of resistance force exerted on an obstacle placed in a gravity driven granular silo flow, 2018, AIChE Journal, 64 : 3849.
58. Vamsi Krishna, Sonu Kumar, K. Anki Reddy, Julian Talbot, Granular silo flow of inelastic dumbbells: clogging and its reduction, 2018, Physical Review E, 98 : 022904.
59. Sonu Kumar, K. Anki Reddy, S. Takada and H. Hayakawa, Scaling law of the drag force in dense granular media, 2018, arXiv preprint arXiv:1712.09057.
60. Sonu Kumar, Manish Dhiman and K. Anki Reddy, Magnus effect in granular media, 2019, Physical Review E , 99:012902.
61. Takatsune Furuta, Sonu Kumar, K. Anki Reddy, Hirofumi Niiya and Hiroaki Katsuragi, Packing- dependent granular friction exerted on a rod withdrawn from a granular layer: the role of shear jamming, 2019, New Journal of Physics, 21:023001
62. Manish Dhiman, Sonu Kumar, K. Anki Reddy and Raghavendra Gupta, Origin of the long-ranged attraction or repulsion between intruders in a confined granular medium, 2020, Journal of Fluid Mechanics, 886, A23.
63. Vamsi Krishna , Sonu Kumar and K. Anki Reddy, Granular particle-shape heterogeneous mixtures discharging through a silo, 2021, Journal of Fluid Mechanics, 912, A22.
64. Bitang Tripura, Sonu Kumar, K. Anki Reddy and Julian Talbot, Shape dependence of the drag and lift forces on the moving intruder in a 2D granular medium, 2021, Particulate Science and Technology, Accepted.
65. Vamsi Krishna and K. Anki Reddy, Granular mixtures discharging through a silo with eccentric orifice location, 2022, Physics of Fluids, Accepted.
66. Vamsi Krishna, K. Anki Reddy, Iker Zuriguel, Hiroaki Katsuragi, Clogging phenomena in a system of asymmetric particles , 2021, Journal of Statistical Mechanics: Theory and Experiment, 6, 063201.
67. Bitang Tripura, A. Vamsi Krishna, Sonu Kumar, K. Anki Reddy, Drag on a circular intruder translating in a shape-heterogeneous granular mixture , 2022, Physical Review E, 106, 014901.
68. Bitang Tripura, Sonu Kumar, Vamsi Krishna, K. Anki Reddy, The rise and sink dependence on the shape of a horizontally wiggling intruder, 2022, arXiv:2207.01000 (Revised version in preparation for Journal of Fluid Mechanics)
69. Vamsi Krishna and K. Anki Reddy, Granular mixtures of dumbbells and discs flowing through a silo with two orifices, 2023 (Revised version in preparation for Physical Review E)