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Mangalampalli Ravikanth - One of the best experts on this subject based on the ideXlab platform.
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synthesis of mono functionalized core modified expanded porphyrin building blocks and covalently linked expanded porphyrin dyads
European Journal of Organic Chemistry, 2011Co-Authors: Yogita Pareek, Mangalampalli RavikanthAbstract:A series of mono-functionalized core-modified expanded porphyrin building blocks such as thiasapphyrin, thiarubyrin, oxasmaragdyrin, and BF2–oxasmaragdyrin have been synthesized by simple condensation of readily available precursors. The mono-functionalized core-modified expanded porphyrin building blocks were used to synthesize the first three examples of covalently linked diphenylethyne-bridged dyads containing two different expanded porphyrin macrocycles, namely thaisapphyrin–BF2–oxasmaragdyrin, thiarubyrin–BF2–oxasmaragdyrin, and thiasapphyrin–thiarubyrin, by coupling appropriate mono-functionalized expanded porphyrin building blocks under mild Pd0 coupling reaction conditions. The three dyads were freely soluble in common organic solvents and characterized by MS, NMR, absorption, electrochemical, and fluorescence techniques. The NMR, absorption, and electrochemical studies indicated that the two macrocycles in the dyads interact weakly with each other and maintain their independent characteristic features. The steady-state fluorescence studies of the dyads showed that the thiasapphyrin and thiarubyrin units are nonfluorescent but fluorescence was observed from the BF2–oxasmaragdyrin unit. However, the quantum yield of the BF2–oxasmaragdyrin unit in the dyads was less than that of monomeric BF2–oxasmaragdyrin because of an enhancement of nonradiative decay channels operating in the dyads. The potential use of two of the three dyads containing the BF2–smaragdyrin subunit as fluorescent sensors for anions was explored. The studies showed that the binding of the anion at the protonated sapphyrin and rubyrin sites in the respective dyads can be followed by the clear changes in the fluorescence band of the BF2–oxasmaragdyrin unit, which indicates that these dyads can be used as fluorescent anion sensors.
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Synthesis of covalently linked unsymmetrical porphyrin pentads containing three different porphyrin subunits.
The Journal of organic chemistry, 2008Co-Authors: Smita Rai, Mangalampalli RavikanthAbstract:The tetrafunctionalized AB3-type porphyrin building blocks containing two different types of functional groups with N4, N3O, N3S, and N2S2 porphyrin cores were synthesized by following various synthetic routes. The AB3-type tetrafunctionalized N4 porphyrin building block was synthesized by a mixed condensation approach, the N3S and N3O porphyrin building blocks by a mono-ol method, and N2S2 porphyrin building block by an unsymmetrical diol method. The tetrafunctionalized porphyrin building blocks were used to synthesize monofunctionalized porphyrin tetrads containing two different types of porphyrin subunits by coupling of 1 equiv of tetrafunctionalized N4, N3O, N3S, and N2S2 porphyrin building block with 3 equiv of monofunctionalized ZnN4 porphyrin building block under mild copper-free Pd(0) coupling conditions. The monofunctionalized porphyrin tetrads were used further to synthesize unsymmetrical porphyrin pentads containing three different types of porphyrin subunits by coupling 1 equiv of monofunction...
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one flask synthesis of mono and trifunctionalized 21 thia and 21 oxaporphyrin building blocks and their application in the synthesis of covalent and noncovalent unsymmetrical porphyrin arrays
Journal of Organic Chemistry, 2004Co-Authors: Iti Gupta, Mangalampalli RavikanthAbstract:A rapid synthetic route has been developed to synthesize mono- and trifunctionalized 21-thia and 21-oxaporphyrin systems using simple precursors such as 2[α-(aryl)-α-hydroxymethyl] thiophene (thiophene mono-ol) and 2[α-(aryl)-α-hydroxymethyl] furan (furan mono-ol), respectively. Condensation of one equivalent of thiophene or furan mono-ol with two equivalents of aryl aldehyde and three equivalents of pyrrole under porphyrin forming conditions followed by column chromatography resulted in functionalized 21-thia or 21-oxaporphyrins. To synthesize monofunctionalized porphyrins, the mono-ol containing the functionalized aryl group was used. The functionalized aldehydes were used to synthesize trifunctionalized porphyrins. The mono-ol method is versatile and applicable to synthesize mono- and trifunctionalized 21-thia and 21-oxaporphyrins containing functional groups such as iodophenyl, ethynylphenyl, hydroxyphenyl, bromophenyl, and pyridyl groups. The monofunctionalized porphyrin building blocks containing io...
Didier Lucor - One of the best experts on this subject based on the ideXlab platform.
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Mono-Block and non-matching multi-block structured mesh adaptation based on aerodynamic functional total derivatives for RANS flow
International Journal for Numerical Methods in Fluids, 2016Co-Authors: A. Resmini, J. Peter, Didier LucorAbstract:Summary An enhanced goal-oriented mesh adaptation method is presented based on aerodynamic functional total derivatives with respect to mesh nodes in a Reynolds-Averaged Navier-Stokes (RANS) finite-volume Mono-Block and non-matching multi-block-structured grid framework. This method falls under the category of methods involving the adjoint vector of the function of interest. The contribution of a Spalart–Allmaras turbulence model is taken into account through its linearization. Meshes are adapted accordingly to the proposed indicator. Applications to 2D RANS flow about a RAE2822 airfoil in transonic, and detached subsonic conditions are presented for the drag coefficient estimation. The asset of the proposed method is patent. The obtained 2D anisotropic Mono-Block mesh well captures flow features as well as global aerodynamic functionals. Interestingly, the constraints imposed by structured grids may be relaxed by the use of non-matching multi-block approach that limits the outward propagation of local mesh refinement through all of the computational domain. The proposed method also leads to accurate results for these multi-block meshes but at a fraction of the cost. Finally, the method is also successfully applied to a more complex geometry, namely, a Mono-Block mesh in a 3D RANS transonic flow about an M6 wing. Copyright © 2016 John Wiley & Sons, Ltd.
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Mono-Block and non-matching multi-block structured mesh adaptation based on aerodynamic functional total derivatives for RANS flow
International Journal for Numerical Methods in Fluids, 2016Co-Authors: A. Resmini, J. Peter, Didier LucorAbstract:An enhanced goal-oriented mesh adaptation method is presented based on aerodynamic functional total derivatives with respect to mesh nodes in a Reynolds-Averaged Navier-Stokes (RANS) finite-volume Mono-Block and non-matching multi-block-structured grid framework. This method falls under the category of methods involving the adjoint vector of the function of interest. The contribution of a Spalart–Allmaras turbulence model is taken into account through its linearization. Meshes are adapted accordingly to the proposed indicator. Applications to 2D RANS flow about a RAE2822 airfoil in transonic, and detached subsonic conditions are presented for the drag coefficient estimation. The asset of the proposed method is patent. The obtained 2D anisotropic Mono-Block mesh well captures flow features as well as global aerodynamic functionals. Interestingly, the constraints imposed by structured grids may be relaxed by the use of non-matching multi-block approach that limits the outward propagation of local mesh refinement through all of the computational domain. The proposed method also leads to accurate results for these multi-block meshes but at a fraction of the cost. Finally, the method is also successfully applied to a more complex geometry, namely, a Mono-Block mesh in a 3D RANS transonic flow about an M6 wing.
Yue-hua Liu - One of the best experts on this subject based on the ideXlab platform.
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Therapeutic Comparison of Two Oral Appliances on Obstructive Sleep Apnea/Hypopnea Syndrome
Chinese Journal of Orthodontics, 2011Co-Authors: Yue-hua LiuAbstract:Objective To compare the objective and subjective effects of two oral appliances in patients with OSAHS.Methods A crossover design trial was carried out in 16 OSAHS patients who wore Mono-Block and two-piece appliances in turn.Each oral appliance needed to be worn for 3 months.There was a two-week washout period between appliance switch.The objective and subjective effects were assessed at the end of wearing oral appliance.One-way ANOVA was carried out to evaluate the parameters.Results Both oral appliances showed remarkable efficacy in OSAHS patients.But the Mono-Block appliance had less improvement in Sleep Efficiency(SE) and Percentage of Delta period( Delta％ )(P＜0.05).Both oral appliances could increase obviously the each segment of upper airway(P＜0.05).But there was no significant difference between the two oral appliances(P ＞0.05).Conclusions Both oral appliances had good efficacies in the treatment of OSAHS.Due to the different characteristics of each appliance,there were more alternatives for OSAHS patients. Key words: obstructive sleep apnea/hypopnea syndrome; Mono-Block oral appliance; twopiece oral appliance; upper airway; objective and subjective effects
Binoy B. Nair - One of the best experts on this subject based on the ideXlab platform.
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Comparison of dimensionality reduction techniques for the fault diagnosis of mono block centrifugal pump using vibration signals
Engineering Science and Technology an International Journal, 2014Co-Authors: N. R. Sakthivel, M Elangovan, Binoy B. Nair, Vijayan Sugumaran, S. SaravanmuruganAbstract:Bearing fault, Impeller fault, seal fault and cavitation are the main causes of breakdown in a mono block centrifugal pump and hence, the detection and diagnosis of these mechanical faults in a mono block centrifugal pump is very crucial for its reliable operation. Based on a continuous acquisition of signals with a data acquisition system, it is possible to classify the faults. This is achieved by the extraction of features from the measured data and employing data mining approaches to explore the structural information hidden in the signals acquired. In the present study, statistical features derived from the vibration data are used as the features. In order to increase the robustness of the classifier and to reduce the data processing load, dimensionality reduction is necessary. In this paper dimensionality reduction is performed using traditional dimensionality reduction techniques and nonlinear dimensionality reduction techniques. The effectiveness of each dimensionality reduction technique is also verified using visual analysis. The reduced feature set is then classified using a decision tree. The results obtained are compared with those generated by classifiers such as Naïve Bayes, Bayes Net and kNN. The effort is to bring out the better dimensionality reduction technique–classifier combination.
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comparison of decision tree fuzzy and rough set fuzzy methods for fault categorization of mono block centrifugal pump
Mechanical Systems and Signal Processing, 2010Co-Authors: N. R. Sakthivel, Vijayan Sugumaran, Binoy B. NairAbstract:Mono-Block centrifugal pumps are widely used in a variety of applications. In many applications the role of Mono-Block centrifugal pump is critical and condition monitoring is essential. Vibration based continuous monitoring and analysis using machine learning approach is gaining momentum. Particularly, artificial neural networks, fuzzy logic have been employed for continuous monitoring and fault diagnosis. This paper presents the use of decision tree and rough sets to generate the rules from statistical features extracted from vibration signals under good and faulty conditions of a Mono-Block centrifugal pump. A fuzzy classifier is built using decision tree and rough set rules and tested using test data. The results obtained using decision tree rules and those obtained using rough set rules are compared. Finally, the accuracy of a principle component analysis based decision tree-fuzzy system is also evaluated. The study reveals that overall classification accuracy obtained by the decision tree-fuzzy hybrid system is to some extent better than the rough set-fuzzy hybrid system.
A. Resmini - One of the best experts on this subject based on the ideXlab platform.
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Mono-Block and non-matching multi-block structured mesh adaptation based on aerodynamic functional total derivatives for RANS flow
International Journal for Numerical Methods in Fluids, 2016Co-Authors: A. Resmini, J. Peter, Didier LucorAbstract:Summary An enhanced goal-oriented mesh adaptation method is presented based on aerodynamic functional total derivatives with respect to mesh nodes in a Reynolds-Averaged Navier-Stokes (RANS) finite-volume Mono-Block and non-matching multi-block-structured grid framework. This method falls under the category of methods involving the adjoint vector of the function of interest. The contribution of a Spalart–Allmaras turbulence model is taken into account through its linearization. Meshes are adapted accordingly to the proposed indicator. Applications to 2D RANS flow about a RAE2822 airfoil in transonic, and detached subsonic conditions are presented for the drag coefficient estimation. The asset of the proposed method is patent. The obtained 2D anisotropic Mono-Block mesh well captures flow features as well as global aerodynamic functionals. Interestingly, the constraints imposed by structured grids may be relaxed by the use of non-matching multi-block approach that limits the outward propagation of local mesh refinement through all of the computational domain. The proposed method also leads to accurate results for these multi-block meshes but at a fraction of the cost. Finally, the method is also successfully applied to a more complex geometry, namely, a Mono-Block mesh in a 3D RANS transonic flow about an M6 wing. Copyright © 2016 John Wiley & Sons, Ltd.
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Mono-Block and non-matching multi-block structured mesh adaptation based on aerodynamic functional total derivatives for RANS flow
International Journal for Numerical Methods in Fluids, 2016Co-Authors: A. Resmini, J. Peter, Didier LucorAbstract:An enhanced goal-oriented mesh adaptation method is presented based on aerodynamic functional total derivatives with respect to mesh nodes in a Reynolds-Averaged Navier-Stokes (RANS) finite-volume Mono-Block and non-matching multi-block-structured grid framework. This method falls under the category of methods involving the adjoint vector of the function of interest. The contribution of a Spalart–Allmaras turbulence model is taken into account through its linearization. Meshes are adapted accordingly to the proposed indicator. Applications to 2D RANS flow about a RAE2822 airfoil in transonic, and detached subsonic conditions are presented for the drag coefficient estimation. The asset of the proposed method is patent. The obtained 2D anisotropic Mono-Block mesh well captures flow features as well as global aerodynamic functionals. Interestingly, the constraints imposed by structured grids may be relaxed by the use of non-matching multi-block approach that limits the outward propagation of local mesh refinement through all of the computational domain. The proposed method also leads to accurate results for these multi-block meshes but at a fraction of the cost. Finally, the method is also successfully applied to a more complex geometry, namely, a Mono-Block mesh in a 3D RANS transonic flow about an M6 wing.