Qualification: 
Ph.D, M.Tech, B-Tech
Email: 
sabarinaths@am.amrita.edu

Dr. Sabarinath S. currently serves as an Assistant Professor at the School for Sustainable Development and at the Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Amritapuri campus.

Dr. Sabarinath S. received his B. Tech. degree in Mechanical Engineering (2007), M. Tech. degree in Machine Design (2014) and Ph. D. in Tribology from National Institute of Technology, Calicut. His research mainly focuses on tribology. He has published several papers in reputed peer-reviewed journals like Lubrication Science - Wiley, Applied Nanoscience-Springer, Journal of Engineering Tribology – Sage, Micro-nano letters, etc. His research interests include Development of Biolubricants, Engine Tribology, Development of Cutting Fluids, Quantum Chemical Interactions of Additives, Nanotribology, Development and Analysis of Magneto Rheological (MR) Fluids, Coatings and Tribology of Biomaterials for Implants. He has several years of experience as a quality control engineer at Pearl GTL project, Shell, Qatar

Awards and Recognition

Sl.No Award Description
1 3rd Rank - M. Tech MG University, 2013
2 Second Runner-up KEMPPI - Weld network award for young engineers competition 2019,  February 6, 2020
3 Royal Society of Chemistry (RSC) award in Nanoscale advances VCAN 2020 (June 17-19, 2020)

Reviewer - Journal

  • Materials Today: Proceeding

Publications

Publication Type: Book Chapter

Year of Publication Title

2020

Sabarinath S., Nair, A. Ajith, Bijo, B. Varghese, Das, H. Kuttuvelil, and Sureshkumar, H., “Biolubricant from Pongamia Oil”, in Tribology in Materials and Manufacturing-Wear, Friction and Lubrication, IntechOpen, 2020.[Abstract]


Recent researches focus on the development of lubricants from non-edible vegetable oil which are environment friendly and renewable. In the current work, an industrial lubricant is formulated from a non-edible vegetable oil viz. pongamia oil (PO) by blending it suitable additives. The additives such as silicon dioxide (SiO2) nanoparticles, tert-butylhydroquinone (TBHQ) and styrene butadiene rubber (SBR) were selected as antiwear, antioxidant and viscosity improver additives respectively for the study. Various lubricant properties of the formulated oil (FO) are studied and comparisons were made against neat PO and popularly available mineral oil lubricant viz. SAE 20W40. It is found that the FO possesses superior viscosity index, and lower coefficient of friction than the commercial SAE 20W40. Moreover, the viscosity range, oxidative stability and the wear scar diameter of the FO is also in the range of SAE 20W40. This work is done with an aim of promoting Pongamia agriculture and reducing soil pollution.

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Publication Type: Journal Article

Year of Publication Title

2020

Sreenidhi P. R., V. John, N., Sabarinath S., Ashfak, A., Subash, C. Karimuthil, and Varghese, S., “Nature-inspired PDMS cumulonimbus micro-energy-harvesting cloud”, Applied Nanoscience, SCI (Impact factor 3.19), vol. 11, no. 127–137, 2020.[Abstract]


Here in this work, nanoenergy-generating films mimicked from cumulonimbus cloud were prepared using deionised water (DI) in polydimethylsiloxane (PDMS). Various characterisation methods have been adopted to verify the content of water as well as the resemblance of the morphological structure of the water-entrapped polymer films with clouds which include scanning electron microscopy and optical reflectance imaging techniques. The water content entrapment in the polymer is verified using the ATR-IR spectroscopy by finding absorbance peaks at 3266 and 1634&nbsp;cm<sup>−1</sup>. Polyethylene terephthalate (PET) sheets with a copper coating (Cu-PET) were used as contact electrodes, and the device was fabricated by the simple sandwiching process. Dielectric studies of the device under an applied electric field were used to illustrate the presence of interfacial hopping as well as orientational polarisation in the device. The device fabricated shows an enhancement of 218% and 562% with an increase in water content from 4:1 to 1:1 and a decrease of 26% and 36.5% with a further increase in water for the generated voltage and current measured, respectively. The optimum concentration of polymer to water is selected as 1:1 and the decrease in current and voltage may be due to the condensation of water molecules leading to fewer contact sites between the water and polymer molecules. The devices showed an increment of voltage and current of 171.1&nbsp;V and 29.16 nA, respectively, with an increase in the force of 1–5&nbsp;N by using an automated input system. The device was tested under various mechanical inputs, and the generated energy used as sensors in the knock sensor, home doorbell system and seabed vibration detector and as a secondary powering source for charging mobile phones and lighting LED.

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2020

Sabarinath S., Sreenidhi P. R., P. Kumar, and Nair, K., “Development of fully formulated eco-friendly nanolubricant from sesame oil”, Applied Nanoscience, SCI (Impact factor 3.19), vol. 10, no. 2, pp. 577-586, 2020.[Abstract]


In the present work, a biodegradable and non-toxic lubricant is formulated from sesame oil (SESO) with viscosity modifiers, antioxidants and antiwear additives. The significance of antiwear additives in SESO blended with antioxidants and viscosity modifiers is evaluated using analysis of variance (ANOVA). The formulated oil is tested for its biodegradability, toxicity, rheological, thermal, tribological and corrosive properties and is compared with commercially available SAE20W40 lubricant. The formulated lubricant is investigated to have better biodegradability, lower toxicity and good thermal properties than SAE20W40. Whereas its pour point, rheological properties, corrosive properties and tribological properties are comparable to that of SAE20W40.

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2019

Sabarinath S., Rajendrakumar, P. K., and K. Nair, P., “Evaluation of tribological properties of sesame oil as biolubricant with SiO2 nanoparticles and imidazolium-based ionic liquid as hybrid additives”, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, SCI (Impact factor 1.31), vol. 233, no. 9, pp. 1306–1317, 2019.[Abstract]


The renewability and ecofriendly nature of vegetable oils make them a competitive candidate to replace depleting petroleum-based mineral oils. However, the poor antiwear properties of vegetable oils restrict them from many industrial applications as lubricants. In the present work, the synergic effect of SiO2 nanoparticles with ionic liquids 1-butyl-3- methylimidazolium tetrafluoroborate and 1-hexyl-3-methylimidazolium tetrafluoroborate as hybrid antiwear additives in enhancing the tribological properties of sesame oil is studied for steel on steel contacts. Morphologies of the worn surfaces and possibilities of tribofilm formation are examined using a field-emission scanning electron microscope and energy-dispersive spectroscopy analysis. A density functional theory analysis is performed to study the existence of intermolecular forces of attraction between ionic liquid and triglyceride molecules. Rheological properties of the blends are evaluated using Anton Paar MCR10 rheometer. Corrosive properties of the oil blends are studied using copper strip corrosion test (ASTM D130).

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2019

Sabarinath S., Nair, K. Prabhakara, and Rajendrakumar, P. Krishnan, “Experimental and quantum chemical investigations on the oxidative stability of sesame oil base stock with synthetic antioxidant additives”, Lubrication Science, SCI (Impact factor 1.485), vol. 31, no. 5, pp. 179–193, 2019.[Abstract]


Depleting resources and increasing environmental pollution caused by the petroleum products made researchers to think about its biodegradable counterparts. Vegetable oils due to its characteristics such as availability, renewability, eco-friendliness, and biodegradability are progressively encouraged as a replacement for mineral oils in lubricant industry, while enhancement of few properties like the oxidative stability aids in the efficient use of them as the base stock. A generous amount of unsaturation in vegetable oils decreases oxidative stability and improves the pour point. Hence, a compromise between these two properties (pour point and oxidative stability) is critical in vegetable oil-based lubricant. In this regard, sesame oil (SESO) possesses high pour point, and presence of natural antioxidants in it imparts superior oxidative stability than any other vegetable oils with a higher level of unsaturation. The addition of certain synthetic antioxidants to the SESO helps in the further improvisation of its oxidative stability to suit it for lubricant purpose. In the present work, the oxidative stability of SESO blended with octyl gallate (OG), salicyl hydroxamic acid, 2,5-di-tert-butyl hydroquinone (DTBHQ), and tertbutyl hydroquinone (TBHQ) are assessed using hot oil oxidation test (HOOT) and differential scanning calorimetry (DSC, ASTM E2009-08). The results are further compared with commercially available mineral oil-based lubricant, SAE20W40. HOOT results show that a blend of SESO + 1.5%DTBHQ + 0.5%OG possesses higher oxidative stability than other antioxidant blends with SESO. In addition, from the DSC results, it is observed that the oxidative onset temperature (OOT) for abovementioned combination (268.10°C) shows an increase of 46.6% than the value of neat SESO (182.79°C) and is nearer to SAE20W40 (277.38°C). Fourier-transform infrared spectroscopy results show that SESO + 1.5%DTBHQ + 0.5%OG combination subjected to HOOT hampers oxidation and hence increases the oxidative stability. The tribological properties of neat and antioxidant added SESO are studied using a four-ball tester. Quantum chemical studies are also performed for antioxidant molecules on the basis of bond dissociation energies, ionisation potential, and HOMO-LUMO energy gap to identify the dominant antioxidant mechanisms.

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2019

Sreenidhi P. R., Sabarinath S., K, S. C., Valiyaneerilakkal, D. Uvais, Parameswaran, P., and Varghese, S., “α-and β-crystalline phases in polyvinylidene fluoride as tribo-piezo active layer for nanoenergy harvester”, High Performance Polymers, SCI (Impact factor 1.031), vol. 31, no. 7, pp. 785-799, 2019.[Abstract]


The manuscript introduces the use of non-electrically polled spin-coated thin polyvinylidene fluoride (PVDF) films as the active layers in a contact electrification-based nanoenergy harvester. The four-layered device utilizes both piezo and triboelectric effect coupled with electrostatic induction. The elucidation of potential generation during contact between crystalline phases (α and β) of PVDF layer material is investigated in the manuscript. Fourier transform infrared–attenuated total reflectance spectroscopy is carried out to illustrate the α- and β-phases in PVDF pellet, prepared film as well as the film after contact. Dynamic contact mode electrostatic force microscopy (DC-EFM) along with atomic force microscopy is used for the evaluation of reverse piezoelectric, local ferroelectric, triboelectric voltage and adhesive energy of the PVDF films before–after contact process. Quantum chemical calculation is performed using density functional theory to explain possible electron transitions in the active layers between the cylindrically symmetric α-phase and electrical double layer charges in the β-phase of PVDF. The interface study of the film is also carried out both experimentally using DC-EFM and through quantum chemical calculations. The fabricated device with the hybrid piezo-tribo layer promises to be a simple and low-cost energy source for the next-generation self-powered electronic devices. The device can also be used as knock sensor in engines as well as a capacitor.

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2018

Sabarinath S., Nair, K. Prabhakara, and Rajendrakumar, P. Krishnan, “Micro and nanoparticles blended sesame oil bio-lubricant: study of its tribological and rheological properties”, Micro & Nano Letters, SCI (Impact factor 0.841), vol. 13, no. 12, pp. 1743-1746, 2018.[Abstract]


Non-renewability, depleting resources and damage caused to the environment by mineral oil-based lubricants are the greatest concerns of this century. Recently, these issues have triggered a global trend to use vegetable oil-based lubricants in industries. Sesame oil (SESO) extracted from widely cultivated tropical crop – sesame (‘Sesamum indicum’) possesses distinctive characteristics such as low pour point and reasonable oxidation stability. However, the poor tribological properties of SESO limit its application as an industrial grade lubricant. Further improvement of these properties can aid its use as potential bio-lubricant in industries. This work encompasses the blending of micro and nanoparticles in SESO with the aim of enhancing its tribological properties to suit many industrial purposes. The tribological properties of SESO with nanoparticles having morphology variation spherical-shaped titanium dioxide (TiO2) and rod-shaped zinc oxide (ZnO) are used. The significance of adding microparticles is also dealt with by using molybdenum disulphide (MoS2). Tribological properties and stability of the above-formulated lubricants with and without the addition of surfactant to particles are studied. The rheological properties of the oil blends are examined using a rheometer. Studies indicate that rod-shaped ZnO blended SESO reduces the coefficient of friction and wear scar diameter by 24.04 and 13.74%, respectively.

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2018

Sabarinath S., K Nair, P., Rajendrakumar, P. K., and Parameswaran, P., “Styrene butadiene rubber as a viscosity improver: experimental investigations and quantum chemical studies”, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, SCI (Impact factor 1.32), vol. 232, no. 4, pp. 427–436, 2018.[Abstract]


The limited viscosity range of vegetable oils restricts their effectiveness as a lubricant in numerous applications. In this work, the viscosity improvement with styrene butadiene rubber as an additive in sesame oil is studied and the results are compared with those of the commonly used viscosity improver, ethyl vinyl acetate, using a rheometer. Sesame oil/styrene butadiene rubber blends show higher increment in viscosity than sesame oil/ethyl vinyl acetate blends. The viscosity variations are further validated using Arrhenius model. A computational quantum chemical software, Gaussian 09, is used to evaluate the binding energies between molecules. Ground state electronic structures of molecules are modeled with density functional theory. Thermal properties such as flash, fire, and pour points have also been evaluated for sesame oil/styrene butadiene rubber blends. Chemical oxygen demand and biological oxygen demand are the parameters chosen to evaluate the biodegradability of sesame oil/styrene butadiene rubber blend.

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2017

Sabarinath S., Nair, K. Prabhakara, and Rajendrakumar, P. Krishnan, “Evaluation of physicochemical, thermal and tribological properties of sesame oil (Sesamum indicum L.): a potential agricultural crop base stock for eco-friendly industrial lubricants”, International Journal of Agricultural Resources, Governance and Ecology, vol. 13, no. 1, pp. 77–90, 2017.[Abstract]


In the past few decades, researchers are striving for the development of safe alternatives to mineral oils which are getting scarce and hazardous to the environment. Oils extracted from agricultural crops are one among the solutions. In the current work, the potentiality of sesame oil (SESO) is tested to use it as an eco-friendly base stock for lubricants. SESO is one of the major agricultural crop oils produced all over the globe. In the current work, the physicochemical, rheological, thermal, oxidative, and tribological properties of SESO are studied and compared with coconut oil (CO), sunflower oil (SUO) and a commercially available mineral oil, SAE 20W40. The fatty acid profiles of vegetable oils are evaluated using Gas Chromatography-Mass Spectrometry (GC-MS) technique. Tribological properties of the oils are assessed using a four-ball tester. Sesame oil is seen to possess excellent thermal and tribological properties. Its viscosity index is high whereas its viscosity range and oxidative stability need to be improved. SESO shows the better coefficient of friction (COF) and its wear scar diameter (WSD) is less compared to other vegetable oils. On further improvement, by adding suitable additives this crop oil base stock can be developed into a competing environmental friendly lubricant.

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2015

A. Andrew, Brilliant, A., Harikrishnan, P. S., Johny, J., Fred, T., Sabarinath S., Rajan, A., and Unnikrishnan, M., “Damage Detection On Composite Beam: FEA & Experiment”, International Journal of Engineering Research & Technology (IJERT), vol. 4, no. 6, pp. 28–39, 2015.[Abstract]


It is required that structures must safely work during its service life. But, damages initiate a breakdown period on the structures. Cracks are among the most encountered damage types in the structures. Structures are weakened by cracks. When the crack size increases in course of time, the structure becomes weaker than its previous condition. Finally, the structure may breakdown due to a minute crack. Therefore, crack detection plays an important role for structural health monitoring applications. Delamination is the separation of layers which are bonded together in composite laminate. In the case of bending loads delamination usually leads to significant loss of bending stiffness and strength. Therefore it is important to detect the presents of delamination at an early stage. The delamination causes reduction of stiffness and thereby the modal frequencies also change. In order to find the damage location and size present in the composite materials, we have to determine changes in modal frequencies of the damaged structure as a function of the damage parameters such as delamination and crack location, size, interface at which it is present. In this work modal analysis is used to determine the crack and delamination in the composite structure. This is done by creating a four layer multi directional laminate of E-Glass /Epoxy in the lamination code of 90/0/0/90 in ANSYS. A parametric study is conducted by varying location, width and length of the crack and delamination.The change in&nbsp;frequency of undamaged and damaged shows that the natural frequency is affected by delamination and crack. The results are validated with experimental modal analysis. From the results, a reverse design process is implemented for finding the damage location at a particular natural frequency.

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Funded Projects

Sl.No Funding agency Reference No: Amount Name Institute Role
1 TEQIP-2 2018 NITC/TEQIP- II/R & D/2014 68,000/- Development of an Eco-friendly Lubricant with Sesame oil as the Base stock NIT Calicut Co-Investigator
2 CERD RSM 2019 CERD/RSM/ME-02/KTU/Research 2/4068/2019 1,33,000/ Characterization and formulation of an environment friendly lubricant from Pongamia (Millettia Pinnata) oil using biodegradable additives. Saintgits College of Engineering