74 research outputs found
A bio-attuned ratiometric hydrogen sulfate ion selective receptor in aqueous solvent: structural proof of the H-bonded adduct
No full textA new cell permeable quinazoline based receptor (1) selectively senses HSO4 ions of nanomolar region in 0.1 M HEPES buffer (ethanol–water: 1/5, v/v) at biological pH over other competitive ions through the proton transfer followed by hydrogen bond formation and subsequent anion coordination to yield the [LHSO4]LH+$3H2O (2) ensemble, which has been crystallographically characterised to ensure the structure property relationship. This non-cytotoxic HSO4 ion selective biomarker has great potential to recognize the intercellular distribution of HSO4 ions in HeLa cells under fluorescence microscope
Investigations Concerning the Structure of Complete Sets
No full textThis paper will discuss developments bearing on three related research directions where Somenath Biswas has made pioneering contributions:
• Isomorphism of Complete Sets
• Creative Sets
• Universal Relations
Some open questions in each of these directions will be highlighted.In series: Progress in Computer Science and Applied Logic (26)Peer reviewe
Free Vibration, Acoustic Response and Supersonic Flutter Analyses of Periodic Structures Using a Wave Propagation Method
No full textA Theoretical Formulation For Flutter Analysis Of A Typical Subsonic Aircraft Wing (SARAS) Using Quasi-Steady Aerodynamic Theory
No full textA Theoretical Formulation For Flutter Analysis Has Been Utilized To Develop A Working Method For Determining Flutter Speed Of A Typical Subsonic Wing (SARAS).A Galerkin Type Of Analysis Has Been Used To Derive The Matrix Form Of Equations From The Differential Equations Of Motion Of The Subsonic Wing . Quasi-Steady Aerodynamic Theory Has Been Used To Model The Aerodynamic Forces . A Computer Code In FORTRAN Has Been Prepared For Generation Of Matrices While The Eigenvalue Analysis Is Performed Through MATLAB. The Code Is Benchmarked Through The Solution Of Flutter Of A Rectangular Wing .The Results From The Code Agree Reasonably With Those Obtained From The Industrial Code NASTRAN.
The Method Is Then Extended To The Flutter Analysis Of The Actual "Clean" Wing Of SARAS, With No Control Surface Effects . The Tapered Wing Is Modeled As A Stepped Assembly Of Constant Section Exam Elements. Results Indicate That The SARAS Wing Is Very Stiff And Therefore Is Not Flutter Prone At All In The Subsonic Regime . To Simulate Subsonic Flutter Conditions, A Hypothetically Reduced Stiffness Analysis Is Performed.
In All The Cases, The Agreement Of The Results With Those Of NASTRAN (That Uses The Doublet Lattice Method, DLM) Indicates The Validity Of The Present Method Of Analysis Using The Quasi-Steady Aerodynamic Theory . The Present Work Can Be Extended To Study More Complicated Cases Of Flutter In SARAS Wing With Control Surface Effects And SARAS T-Tail Assembly Which Are Expectedly Quite Prone To Subsonic Flutter
Analysis of shear locking in Tomoshenko beam elements using the function space approach
No full textElements based purely on completeness and continuity requirements perform erroneously in a certain class of problems. These are called the locking situations, and a variety of phenomena like shear locking, membrane locking, volumetric locking, etc have been identified. Locking has been eliminated by many techniques, e.g reduced integration, addition of bubble functions, use of assumed strain approaches mixed and hybrid approaches etc. In this paper, we review the field consistency paradigm using a function space model, and propose a method to identify field inconsistent spaes for projections that show locking behaviour. The case of the Timoshenko beam serves as an illustrative example
Lectures in FEA (Fundamentals) Lecture 2 - Variational Principles in Computational Solid Mechanics
No full textAnalysis of delayed convergence in the three-noded Timoshenko beam element using the function space approach
No full textDespite satisfying only completeness and continuity requirements, elements often perform erroneously in a certain class of problems, called the locking situations, where they display spurious stress oscillations and enhanced stiffness properties. The function space approach that effectively substantiates the postulates of the field consistency paradigm is an efficient tool to reveal the fundamental cause of locking phenomena, and propose methods to eliminate this pathological problem. In this paper, we review the delayed convergence behaviour of three-noded Timoshenko beam elements using the rigorous function space approach. Explicit, closed form algebraic results for the element strains, stresses and errors have been derived using this method. The performance of the field-inconsistent three-noded Timoshenko beam element is compared with that of the field-inconsistent two-noded beam element. It is demonstrated that while the field-inconsistent two-noded linear element is prone to shear locking, the field-inconsistent three-noded element is not very vulnerable to this pathological problem, despite the resulting shear oscillations
Analysis of Laterally Loaded Fixed-Headed Single Pile in Multilayered Soil Using P-Y Approach
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