National Institute of Technology, Karnataka

About: National Institute of Technology, Karnataka is a education organization based out in Mangalore, Karnataka, India. It is known for research contribution in the topics: Corrosion & Cloud computing. The organization has 5017 authors who have published 7057 publications receiving 70367 citations.

Contact Angle Measurements

Abstract: Contact angle has been an important parameter to determine the wetting ability of the polymer membrane surface. Contact angle has gained interest in surface science in regards to its fundamental aspects and application point of view. This chapter will give an insight into fundamentals of contact angle including the theoretical backgrounds, brief history, and importance of contact angle. The various factors that affect the contact angle measurement will also be discussed. The chapter will also present contact angle hysteresis phenomena, comprising of advancing and receding contact angles along with the manifestations of contact angle hysteresis. The chapter will highlight the various methods and techniques available for the measurement of contact angle along with the comprehensive description of the methods. The chapter also covers the application contact angle on surface characterization, permeation, and antifouling nature of the membrane.

Third order nonlinear optical properties and optical limiting in donor/acceptor substituted 4′-methoxy chalcone derivatives

Abstract: The third order nonlinear optical properties of 4′-methoxy chalcone and its derivatives have been investigated using a single-beam Z-scan technique with nanosecond laser pulses at 532 nm. The 4′-methoxy chalcone and its derivatives are donor–acceptor–acceptor (D–A–A) and donor–acceptor–donor (D–A–D) type intramolecular charge transfer molecules. The nonlinear response in these molecules was found to increase with increase in (a) the electron acceptor strength in D–A–A type and (b) the donor strength of the substituted group in D–A–D type molecules. The χ(3) value in these molecules is found to be of the order of 10-13 esu. The observed increase in the third order nonlinearity in these molecules clearly indicates the electronic origin. The compounds exhibit good optical limiting at 532 nm. The best optical limiting behavior was observed with the molecule substituted by a strong electron donor.