229 research outputs found
Irregular particle motion simulator-3D (IPMS-3D)
No full textIrregular Particle Motion Simulator-3D (IPMS-3D), a concrete simulation package developed by a group of researchers in the department of civil engineering at IIT Kharagpur. Tests 1.Hardened concrete simulations Tensile test, Compression test, Bending test, shear test, Abrasion test, 2.Fresh concrete simulations Slump test, Flowability test, Shear test 3.Fabric study Developers Prof. Arghya Deb (Head) Ramakrishna Dandapat Subha Ghosh Kumar Anjneya Subham Mukherj
Simultaneous presence of mono- and bi-cationic bipyridyls within a metal-organic supramolecular host: crystal structure, spectral and Hirshfeld surface analysis
No full textA new supramolecular metal-organic complex, {[Fe(CN)6]3-(H2bipy)2+(Hbipy)+·3H2O} (where bipy ipywhere biolecular metal-organic complex, {[Fe(CN)ccepted: 30 October 2022rized by single crystal X-ray crystallographic study (SC-XRD), powder X-ray diffraction (PXRD) and other spectroscopic analysis. Structural analysis reveals that the complex crystallizes in monoclinic space group P21/c and is a 3 D supramolecular complex. Cyanide-water hydrogen bonding interactions between {Fe(CN)6}3- and guest water molecules form a wave-like 2 D supramolecular layer structure parallel to the crystallographic ac-plane with the formation of rectangular cavities of dimension 10.6 × 9.8 Å. These 2 D layers are further connected by O3W-H2W3···O1W hydrogen bonding interactions to form a 3 D supramolecular structure with the creation of 1 D supramolecular channels along the crystallographic a-axis. The bi-cationic (H2bipy)2+ form two different N+-H···water hydrogen bonding interactions (N8+-H8···O2W and N7+-H7···O3W) with two different water molecules and reside within the rectangular cavities. Monocationic (Hbipy)+ moieties form a 1 D supramolecular chain structure through repetitive N···H-N+ hydrogen bonding interactions and are present within the 1 D supramolecular channels. In addition, these two different types of bipy moieties are interconnected to each other through π···π interactions. Hirshfeld surface analysis and the corresponding 2 D fingerprint plots clearly identify the presence of different types of supramolecular interactions between the two differently charged bipyridyl moieties and the host framework, and N-H/H-N contacts, corresponding to the hydrogen bonding interactions, have a significant contribution to the total surface. Both the absorption and emission spectra of the complex have also been studied. </p
A water soluble Ni-Schiff base complex for homogeneous green catalytic C S cross-coupling reactions
Get PDFSince the embarkation of C – S cross-coupling from aryl halides with thiols a handful of works have been
contemplated in aqueous medium. Herein, we report an example of a water soluble Ni-Schiff base complex as the green catalyst for the synthesis of thioethers. We have synthesized a Ni-Schiff base complex [NiL(H2O)2 ](ClO4)2 using N 4 -donor Schiff base ligand (1,3-bis(((E)-pyridin-2-ylmethylene)amino)propan-2-ol) and characterized by single crystal X-ray diffraction (SC-XRD) study along with different spectral analyses. The complex is mono-nuclear and cationic in nature having two perchlorate anions. Two water molecules remain coordinated with the Ni(II)-centre. The hydrogen bonding interaction through coordinated water and perchlorate anions connect the monomeric units to form 2D supramolecular structure. Based on its aqueous solubility, the complex has been used for the catalytic C – S cross-coupling reaction between aryl iodide and aryl or alkyl thiols using TBAB at 60 ◦ C in aqueous media (yield 92%). At room temperature, an isolated yield of 57% can be achieved. This environmentally benign protocol is paramount in view of the environmental sustainability
Multifunctional Interpenetrated 3D Supramolecular Structure Based on 1D Coordination Polymers: Selective Adsorption, Magnetism, Optical Property, Theoretical Analysis, and Electrical Conductivity
No full textA paddle-wheel-based multifunctional 1D coordination polymer (CP) {[Cu 2 (4-Cl-Bz) 4 (4,4′-bipy)](DMF) 2 } n (where 4-Cl-BzH = 4-chlorobenzoic acid, 4,4′-bipy = 4,4′-bipyridine, and DMF = dimethylformamide), (complex 1) have been synthesized via the solvothermal method and characterized by single-crystal X-ray diffraction analysis along with other spectroscopic studies. Structural analysis shows that 1 crystallizes in the tetragonal P4 /ncc space group and 1D coordination chains are formed by connecting [Cu 2 (4-Cl-Bz) 4 ] paddle wheel units using 4,4′-bipy moieties along the crystallographic c axis. These 1D coordination chains are assembled to each other through weak π···π interactions to form interpenetrated 3D supramolecular structure, forming channels along the [1 1 0] and [−1 1 0] direction hosting DMF molecules. Hirshfeld surface analysis and corresponding 2D fingerprint plots indicate that π···π interaction is the major interaction among the coordination chains. Thermal analysis shows that guest DMF molecules are released within the temperature range of 70−150 °C and powder X-ray diffraction (PXRD) analysis reveals the quenching of the void space after removal of the solvent molecules. The desolvated framework selectively adsorbs CO 2 over N 2 . The magneto-luminescent behavior of the framework has also been studied. This π-induced 3D supramolecular complex shows semiconducting behavior and conductivity increases upon desolvation
Irregular particle motion simulator-3D (IPMS-3D)
No full textIrregular Particle Motion Simulator-3D (IPMS-3D), a concrete simulation package developed by a group of researchers in the department of civil engineering at IIT Kharagpur. Tests 1.Hardened concrete simulations Tensile test, Compression test, Bending test, shear test, Abrasion test, 2.Fresh concrete simulations Slump test, Flowability test, Shear test 3.Fabric study Developers Prof. Arghya Deb (Head) Ramakrishna Dandapat Subha Ghosh Kumar Anjneya Subham MukherjiTHIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Short-chain n-alkanes in benthic mats and mosses from the Larsemann Hills, East Antarctica
No full textVariation in leaf colour (green, red and grey) of mosses and lake benthic mats in Antarctica is often linked to water stress and ultraviolet light (UV-B) exposure. Changes in the abundance of organic compounds, such as pectin and phenols, are associated with mechanisms protecting against desiccation and UV radiation. However, the function of n-alkanes, especially against UV radiation, is rarely examined. Here, gas chromatography–mass spectrometry and Fourier-transform infrared spectroscopy analyses were performed to study the variation in n-alkanes in freshwater lake benthic mats and mosses collected from the Larsemann Hills in East Antarctica. Stable isotopes of organic carbon and nitrogen, environmental DNA characterisation and microscopy-based analyses are used to estimate the presence of cyanobacteria, algae and diatoms in moss and benthic mat consortia. Variation in the short-chain (n-C17 to n-C20) versus long-chain (n-C21 to n-C30) n-alkanes in the mosses and benthic mats with their colour were noted. The research links the relative abundance of short-chain n-alkanes to the UV-B exposure and proposes that Antarctic mosses and benthic mats synthesise short-chain n-alkanes for protection against UV-B.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Sanitary Engineerin
Design and experimental validation of robust PID control for a power converter in a DC microgrid application
No full textIn a DC microgrid, power electronic DC-DC converters are interfaced with DC loads that pose a stringent requirement of maintaining constant DC output voltage across the load terminals. In particular, the problem of controlling the load voltage of nonminimum phase (NMP) DC-DC boost converter with the measured load voltage under voltage mode control (VMC) is addressed. This control problem is challenging due to NMP dynamics and restricts the achievable bandwidth in the closed-loop operation. To improve the closed-loop performance of NMP boost-type converter against the disturbances (external) and uncertainty in DC microgrid environment, the Quantitative feedback theory (QFT) is used to synthesize a robust PID controller systematically. The merits of the proposed robust PID design procedure using QFT are as follows: (i) it does not require any tuning of the PID values unlike in the conventional PID design which heavily depends on the ad-hoc tuning, (ii) the dynamics of the disturbance (load current and input voltage variations) are accounted in the synthesis stage that further improves the disturbance effect minimization on the load voltage response, and (iii) the simple, straight forward design of the right half plane zero of boost-type DC-DC converter with the bandwidth limitations. The proposed design is illustrated extensively using the simulation with the external disturbances and demonstrated its advantages over a conventional PID. Finally, under various regulatory scenarios, experiments are performed to validate the simulation of the proposed PID design without retuning the controller parameters. The superior dynamic performance of the proposed PID is delineated in experimental results and provides more robustness in different scenarios as compared to the conventional PID
Improved Mean Variance Mapping Optimization for the Travelling Salesman Problem
No full textThis paper presents an improved Mean Variance Mapping Optimization to address and solve the NP-hard combinatorial problem, the travelling salesman problem. MVMO, conceived and developed by István Erlich is a recent addition to the large set of heuristic optimization algorithms with a strategic novel feature of mapping function used for mutation on basis of the mean and variance of the population set initialized. Also, a new crossover scheme has been proposed which is a collective of two crossover techniques to produce fitter offsprings. The mutation technique adopted is only used if it converges towards more economic traversal. Also, the change in control parameters of the algorithm doesn’t affect the result thus making it a fine algorithm for combinatorial as well as continuous problems as is evident from the experimental results and the comparisons with other algorithms which has been tested against the set of benchmarks from the TSPLIB library.</p
A comparative study of dexamethasone ointment along with triamcinolone acetonide in treatment of recurrent aphthous stomatitis
No full textAim: To assess and compare the efficacy of dexamethasone ointment with triamcinolone acetonide, the gel form, in the treatment of minor recurrent aphthous stomatitis (RAS). Materials and Methods: This was a randomized clinical trial of 60 patients of either sex with clinically diagnosed RAS who were randomly divided into two groups—the dexamethasone ointment group (Group I) and the triamcinolone acetonide gel group (Group II). Patients were asked to apply the gel three times a day on each ulcer. Estimation of the efficacy of gel was done based on the time required for regression in pain, size, and number of ulcers. Results: The results showed there was a significant difference in size, pain, number, and duration of ulcers in Group I and Group II within 7 days. However, in both groups, no significant difference was noted in the treatment of RAS. Conclusion: Dexamethasone ointment was found to be efficient in this treatment and was safe as evaluated using clinical assessments
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