scholarly journals Investigation of Effect of Pore Shape, Position and Passivation on the Thermoelectric Properties of Porous Armchair Silicene Nanoribbons

2019 ◽  
Vol 8 (3) ◽  
pp. 25-31
Author(s):  
Rajneesh Kumari ◽  
Deep Kamal Kaur Randhawa ◽  
Sukhdeep Kaur
Keyword(s):  
Thermoelectric Properties ◽  
Ballistic Transport ◽  
Empirical Method ◽  
Basis Set ◽  
Effect Of Temperature ◽  
Pore Shape ◽  
Thermoelectric Efficiency ◽  
Silicene Nanoribbons ◽  
Semi Empirical ◽  
Brenner Potential

In this paper, thermoelectric properties of porous armchair silicene nanoribbons (ASiNRs) have been investigated as a function of pore shape, position and passivation using the Non-equilibrium Green’s function (NEGF) method and Extended Huckel Technique (EHT). Here, nanopores of circular, rectangular, rhombus and triangular nature at different positions have been incorporated with an intention to optimize the structure for maximum thermoelectric figure of merit. In addition, the effect of passivation of the pore edges on the thermoelectric performance has been studied for all the shapes. Further, the effect of temperature variation on the thermoelectric efficiency has been studied. Ballistic transport regime and semi-empirical method using Huckel basis set are used to obtain the electrical properties, while the Brenner potential is used for the phononic system.

scholarly journals Enhanced Thermoelectric Properties of Armchair Graphene Nanoribbons with Pore Passivation

2018 ◽  
Vol 7 (2) ◽  
pp. 149-153
Author(s):  
Sukhdeep Kaur ◽  
Deep Kamal Kaur Randhawa ◽  
Sukhleen Bindra Narang
Keyword(s):  
Thermoelectric Properties ◽  
Waste Heat ◽  
Graphene Nanoribbons ◽  
Ballistic Transport ◽  
Thermoelectric Efficiency ◽  
Hydrogen Atoms ◽  
Armchair Graphene Nanoribbons ◽  
Semi Empirical ◽  
Thermoelectric Parameters ◽  
Armchair Graphene

There is a need to discover efficient thermoelectric materials that can generate electricity from waste heat and could play an important role in a global sustainable energy solution. Graphene Nanoribbons have been explored for a range of pore dimensions in order to achieve better thermoelectric performance. In this paper, we investigate the thermoelectric properties of porous armchair graphene nanoribbons by introducing hydrogen atoms as passivators at the pore surfaces. The aim of this work is to study the influence of pore passivation on the thermoelectric parameters as a function of pore geometry so as to open the possibility for an optimal pore engineering which can significantly improve the thermoelectric efficiency. The results show that the phonon thermal conductivity has a very little dependence on the pore edge passivation. An improvement in thermoelectric figure of merit is achieved due to the increased values of the power factor with consistent values of thermalconductivity. The unique thermoelectric properties of graphene nanoribbons with pore passivation suggest their great potentials for nanoscale thermoelectric applications. Within ballistic transport regime, semi-empirical extended Huckel method has been used for electrical properties while Tersoff potential has been employed for phononic calculations.

scholarly journals Enhanced thermoelectric efficiency in ferromagnetic silicene nanoribbons terminated with hydrogen atoms

2014 ◽  
Vol 16 (25) ◽  
pp. 12900-12908 ◽  
Author(s):  
K. Zberecki ◽  
R. Swirkowicz ◽  
M. Wierzbicki ◽  
J. Barnaś
Keyword(s):  
Ab Initio ◽  
Thermoelectric Properties ◽  
Thermoelectric Efficiency ◽  
Hydrogen Atoms ◽  
Silicene Nanoribbons

Using ab initio methods we calculate thermoelectric and spin thermoelectric properties of silicene nanoribbons with bare, mono-hydrogenated and di-hydrogenated edges.

scholarly journals Molecular Modelling, Docking and Pharmacokinetic Studies of N-Arylidenequinoline-3-Carbohydrazides Analogs as Novel β-Glucuronidase Inhibitors

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Muhammad Tukur Ibrahim ◽  
Adamu Uzairu ◽  
Abdullahi Bello Umar ◽  
Abubakar Sadiq Bello ◽  
Yusuf Isyaku
Keyword(s):  
Geometry Optimization ◽  
Docking Study ◽  
Empirical Method ◽  
Basis Set ◽  
Pharmacokinetic Studies ◽  
Amino Acid Residues ◽  
Molecular Docking Study ◽  
Data Set ◽  
New Compounds ◽  
Semi Empirical

Quantitative structure-activity relationships (QSAR) modelling on 30 N-Arylidenequinoline-3-carbohydrazides analogs was performed using Multi-Linear Regression (MLR) analysis adopting Genetic Function Algorithm (GFA) method. Semi empirical method using PM6 basis set was used for complete geometry optimization of the data set. The best model was chosen based on its statistical fit due to it good internal and external validations. From the Williams plot, it can be inferred that the reported model can make prediction of new compounds that are not within the data set. The molecular docking study showed that, the most active chemical in the data set was better than the standard β-glucuronidase inhibitor both in terms of binding scores and the amino acid residues that interacted with the drug and β-glucuronidase enzyme. The Pharmacokinetic studies indicated that none of the chemicals violated any of the condition set by the Lipinski′s Rule of five which confirm the bioavailability of these chemicals. The results these findings give room for designing novel β-glucuronidase inhibitors that are highly effective.                                                Resumen. Se llevó a cabo la técnica de QSAR en 30 analogos de N-arilidenequinolina-3-carbohidrazidas mediante el analisis de regresesión lineal múltiple (MLS) adopatando el método del algoritmo de función genética (GFA). Para la optimización completa de la geometría del conjunto de datos se utilizó un método semiémpirico del conjunto de bases PM6. El mejor modelo fue elegido basado en función de su ajuste estadístico debido a su validación interna y externa. A partir de la gráfica de Williams, se puede inferir que el modelo reportado puede predecir nuevos compuestos que no se encuentran en el conjunto de datos. Este estudio de acomplamiento molecular mostró que, el químico más activo del conjunto de datos fue mejor que el inhibidor estándar β-glucuronidasa, tanto en términos de unión y en términos de  interacción de los residuos con el fármaco y la enzima β-glucuronidasa. Los estudios farmacocinéticos que indicaron que ninguno de los fármacos incumple ninguna de las condiciones establecidas por la regla de cinco de Lipinski, en donde se confirma la biodisponibilidad de estos químicos. Los resultados de los hallazgos computacionales permiten diseñar nuevos inhibidores de la β-glucuronidasa que son altamente efectivos.

Modeling the Effects of O-sulfonation on the CID of Serine

2020 ◽  
Author(s):  
Kenneth Lucas ◽  
George Barnes
Keyword(s):  
Sulfo Group ◽  
High Energy ◽  
Empirical Method ◽  
Side Chain ◽  
Energy Structure ◽  
Direct Dynamics ◽  
Theoretical Mass ◽  
Intermolecular Proton Transfer ◽  
Dynamics Simulations ◽  
Semi Empirical

We present the results of direct dynamics simulations and DFT calculations aimed at elucidating the effect of \textit{O}-sulfonation on the collision induced dissociation for serine. Towards this end, direct dynamics simulations of both serine and sulfoserine were performed at multiple collision energies and theoretical mass spectra obtained. Comparisons to experimental results are favorable for both systems. Peaks related to the sulfo group are identified and the reaction dynamics explored. In particular, three significant peaks (m\z 106, 88, and 81) seen in the theoretical mass spectrum directly related to the sulfo group are analyzed as well as major peaks shared by both systems. Our analysis shows that the m\z 106 peaks result from intramolecular rearrangements, intermolecular proton transfer among complexes composed of initial fragmentation products, and at high energy side-chain fragmentation. The \mz 88 peak was found to contain multiple constitutional isomers, including a previously unconsidered, low energy structure. It was also seen that the RM1 semi empirical method was not able to obtain all of the major peaks seen in experiment for sulfoserine. In contrast, PM6 did obtain all major experimental peaks.

Theoretical investigation of Ramachandran plot of N-formyl-L-alanine-amide

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Genetic Algorithm ◽  
Theoretical Investigation ◽  
Energy Analysis ◽  
Empirical Method ◽  
Conformational Space ◽  
Ramachandran Plot ◽  
Global Minima ◽  
Reasonable Time ◽  
Semi Empirical

The full conformational space of N-formyl-L-alanine-amide was explored by the semi-empirical method AM1 coupled to the Multi Niche Crowding (MNC) genetic algorithm implemented in a package of programs developed in our laboratory. The structural and energy analysis of the resulting conformational space E(,ψ) exhibits 5 regions or minima ɣL, ɣD, ɛL, D and αD. The technique provides better detection of local and global minima within a reasonable time.

scholarly journals How Good Is the STW Sensor? An Account from a Larger Shipping Company

2021 ◽  
Vol 9 (5) ◽  
pp. 465
Author(s):  
Angelos Ikonomakis ◽  
Ulrik Dam Nielsen ◽  
Klaus Kähler Holst ◽  
Jesper Dietz ◽  
Roberto Galeazzi
Keyword(s):  
High Frequency ◽  
Additional Data ◽  
Empirical Method ◽  
Influential Factor ◽  
Sensor Data ◽  
Sea State ◽  
Shipping Company ◽  
Frequency Sensor ◽  
Semi Empirical

This paper examines the statistical properties and the quality of the speed through water (STW) measurement based on data extracted from almost 200 container ships of Maersk Line’s fleet for 3 years of operation. The analysis uses high-frequency sensor data along with additional data sources derived from external providers. The interest of the study has its background in the accuracy of STW measurement as the most important parameter in the assessment of a ship’s performance analysis. The paper contains a thorough analysis of the measurements assumed to be related with the STW error, along with a descriptive decomposition of the main variables by sea region including sea state, vessel class, vessel IMO number and manufacturer of the speed-log installed in each ship. The paper suggests a semi-empirical method using a threshold to identify potential error in a ship’s STW measurement. The study revealed that the sea region is the most influential factor for the STW accuracy and that 26% of the ships of the dataset’s fleet warrant further investigation.

scholarly journals An Investigation into the Approximations Used in Wave Packet Molecular Dynamics for the Study of Warm Dense Matter

Plasma ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 294-308
Author(s):  
William A. Angermeier ◽  
Thomas G. White
Keyword(s):  
Molecular Dynamics ◽  
Wave Packet ◽  
Hydrogen Plasma ◽  
Valence Bond ◽  
Dense Matter ◽  
Basis Set ◽  
Warm Dense Matter ◽  
Scaling Parameters ◽  
Oppenheimer Approximation ◽  
Semi Empirical

Wave packet molecular dynamics (WPMD) has recently received a lot of attention as a computationally fast tool with which to study dynamical processes in warm dense matter beyond the Born–Oppenheimer approximation. These techniques, typically, employ many approximations to achieve computational efficiency while implementing semi-empirical scaling parameters to retain accuracy. We investigated three of the main approximations ubiquitous to WPMD: a restricted basis set, approximations to exchange, and the lack of correlation. We examined each of these approximations in regard to atomic and molecular hydrogen in addition to a dense hydrogen plasma. We found that the biggest improvement to WPMD comes from combining a two-Gaussian basis with a semi-empirical correction based on the valence-bond wave function. A single parameter scales this correction to match experimental pressures of dense hydrogen. Ultimately, we found that semi-empirical scaling parameters are necessary to correct for the main approximations in WPMD. However, reducing the scaling parameters for more ab-initio terms gives more accurate results and displays the underlying physics more readily.

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