Design of optimal band-stop FIR filter using L1-norm based RCGA

AbstractIn this paper, an optimal design of linear phase digital finite impulse response (FIR) band stop (BS) filter using the L1-norm based real-coded genetic algorithm (L1-RCGA) is presented. Although RCGA has proved its ability to overcome the drawbacks associated with conventional gradient-based optimization methods of filter design, it is applied here with a novel fitness function based on the L1-norm. This leads to a global optimal solution along with the improvement in filter design with same specifications. The designed filter pursues a better response in terms of flat passband, high stopband attenuation and fast convergence. The simulation results justify that the proposed FIR BS filter using L1-RCGA outperforms the existing optimization techniques, the L1-method and particle swarm optimization (PSO) and the conventional methods such as least-squares (LS) approach, Kaiser window method and the Parks McClellan (PM) algorithm. A detailed analysis is performed to evaluate the performance of the designed filters

ExoMol line lists XXV: A hot line list for silicon sulphide, SiS

SiS has long been observed in the circumstellar medium of the carbon-rich star IRC+10216 CW Leo. Comprehensive and accurate rotation-vibrational line lists and partition functions are computed for 12 isotopologues of silicon sulphide ($^{28}$Si$^{32}$S, $^{28}$Si$^{34}$S, $^{29}$Si$^{32}$S, $^{28}$Si$^{33}$S, $^{30}$Si$^{32}$S, $^{29}$Si$^{34}$S, $^{30}$Si$^{34}$S, $^{28}$Si$^{36}$S, $^{29}$Si$^{33}$S, $^{29}$Si$^{36}$S, $^{30}$Si$^{33}$S, $^{30}$Si$^{36}$S) in its ground (X $^1\Sigma^+$) electronic state. The calculations employ an existing spectroscopically accurate potential energy curve (PEC) derived from experimental measurements and a newly-computed ab initio dipole moment curve (DMC). The $^{28}$Si$^{32}$S line list includes 10104 states and 91715 transitions. These line lists are available from the ExoMol website www.exomol.com and the CDS database

Empirical normal intensity distribution for overtone vibrational spectra of triatomic molecules

Theoretical calculations are contributing a significantly higher proportion of data to contemporary spectroscopic databases, which have traditionally relied on experimental observations and semi-empirical models. It is now a common procedure to extend calculated line lists to include ro-vibrational transitions between all bound states of the ground electronic state up to the dissociation limit. Advanced ab initio methods are utilized to calculate the potential energy and dipole moment surfaces (PESs and DMSs), and semi-empirical PESs are then obtained by combining ab initio and experimental data. The objective is to reach high accuracy in the calculated transition intensities for all parts of spectrum, i.e. to increase the predictive power of the model. We show that in order to perform this task, one needs, in addition to the standard improvements of the PES and DMS in the spectroscopically accessible regions, to extend the ab initio calculations of the PES towards the united-atom limit along the stretching coordinates. The argument is based on the correlation between the intensities of high-overtone transitions and the repulsive potential wall that has previously been theoretically established for diatomic molecules and is empirically extended here to linear and nonlinear triatomic molecules. We generate partial line lists for water and ozone, and together with an already available line list for carbon dioxide, we derive the normal intensity distribution, which is a direct consequence of this correlation. The normal distribution is not an instrument to compute highly accurate intensities, rather it is a means to analyze the intensities computed by the traditional methods

The 2020 release of the ExoMol database:Molecular line lists for exoplanet and other hot atmospheres

The ExoMol database (www.exomol.com) provides molecular data for spectroscopic studies of hot atmospheres. While the data is intended for studies of exoplanets and other astronomical bodies, the dataset is widely applicable. The basic form of the database is extensive line lists; these are supplemented with partition functions, state lifetimes, cooling functions, Land\'e g-factors, temperature-dependent cross sections, opacities, pressure broadening parameters, $k$-coefficients and dipoles. This paper presents the latest release of the database which has been expanded to consider 80 molecules and 190 isotopologues totaling over 700 billion transitions. While the spectroscopic data is concentrated at infrared and visible wavelengths, ultraviolet transitions are being increasingly considered in response to requests from observers. The core of the database comes from the ExoMol project which primarily uses theoretical methods, albeit usually fine-tuned to reproduce laboratory spectra, to generate very extensive line lists for studies of hot bodies. The data has recently been supplemented by line lists deriving from direct laboratory observations, albeit usually with the use of ab initio transition intensities. A major push in the new release is towards accurate characterisation of transition frequencies for use in high resolution studies of exoplanets and other bodies

A Review of Basic Bioinformatic Techniques for Microbial Community Analysis in an Anaerobic Digester

Biogas production involves various types of intricate microbial populations in an anaerobic digester (AD). To understand the anaerobic digestion system better, a broad-based study must be conducted on the microbial population. Deep understanding of the complete metagenomics including microbial structure, functional gene form, similarity/differences, and relationships between metabolic pathways and product formation, could aid in optimization and enhancement of AD processes. With advancements in technologies for metagenomic sequencing, for example, next generation sequencing and high-throughput sequencing, have revolutionized the study of microbial dynamics in anaerobic digestion. This review includes a brief introduction to the basic process of metagenomics research and includes a detailed summary of the various bioinformatics approaches, viz., total investigation of data obtained from microbial communities using bioinformatics methods to expose metagenomics characterization. This includes (1) methods of DNA isolation and sequencing, (2) investigation of anaerobic microbial communities using bioinformatics techniques, (3) application of the analysis of anaerobic microbial community and biogas production, and (4) restriction and prediction of bioinformatics analysis on microbial metagenomics. The review has been concluded, giving a summarized insight into bioinformatic tools and also promoting the future prospects of integrating humungous data with artificial intelligence and neural network software

Design of optimal band-stop FIR filter using L1-norm based RCGA

In this paper, an optimal design of linear phase digital finite impulse response (FIR) band stop (BS) filter using the L1-norm based real-coded genetic algorithm (L1-RCGA) is presented. Although RCGA has proved its ability to overcome the drawbacks associated with conventional gradient-based optimization methods of filter design, it is applied here with a novel fitness function based on the L1-norm. This leads to a global optimal solution along with the improvement in filter design with same specifications. The designed filter pursues a better response in terms of flat passband, high stopband attenuation and fast convergence. The simulation results justify that the proposed FIR BS filter using L1-RCGA outperforms the existing optimization techniques, the L1-method and particle swarm optimization (PSO) and the conventional methods such as least-squares (LS) approach, Kaiser window method and the Parks McClellan (PM) algorithm. A detailed analysis is performed to evaluate the performance of the designed filters

Optimal design of FIR high pass filter based on L1 error approximation using real coded genetic algorithm

In this paper, an optimal design of linear phase digital finite impulse response (FIR) highpass (HP) filter using the L1-norm based real-coded genetic algorithm (RCGA) is investigated. A novel fitness function based on L1 norm is adopted to enhance the design accuracy. Optimized filter coefficients are obtained by defining the filter objective function in L1 sense using RCGA. Simulation analysis unveils that the performance of the RCGA adopting this fitness function is better in terms of signal attenuation ability of the filter, flatter passband and the convergence rate. Observations are made on the percentage improvement of this algorithm over the gradient-based L1 optimization approach on various factors by a large amount. It is concluded that RCGA leads to the best solution under specified parameters for the FIR filter design on account of slight unnoticeable higher transition width

Conventional as well as microwave assisted synthesis and antimicrobial screening of 4-aryl-3-chloro-1-[(5-nitroindazol-1-yl) acetamido]-2-oxo-azetidines

89-97Several new 4-aryl-3-chloro-1-[(5-nitroindazol-1-yl) acetamido]-2-oxo-azetidines 4a-l have been synthesized from 2-(5-nitroindazol-1-yl) acetamidyl amino arylidenes 3a-l. The reactions have been carried out by both conventional as well as microwave method. The structures of all these compounds are confirmed by IR, 1H and 13C NMR, FAB-mass spectra and also by microanalytical data. All the synthesized compounds have been screened for their antibacterial activity against Escherichia coli, Bacillus subtilis and Salmonella typhi and antifungal activity against Aspergillus flavus, Penicillium citrinum and Fusarium oxysporum. Some of the synthesized compounds exhibit significant antibacterial and antifungal activities

Influence of Radicals on Magnetization Relaxation Dynamics of Pseudo-Octahedral Lanthanide Iminopyridyl Complexes

Controlling quantum tunneling of magnetization (QTM) is a persistent challenge in lanthanide-based single-molecule magnets. As the exchange interaction is one of the key factors in controlling the QTM, we targeted lanthanide complexes with an increased number of radicals around the lanthanide ion. On the basis of our targeted approach, a family of pseudo-octahedral lanthanide/transition-metal complexes were isolated with the general molecular formula of [M­(L^•–)₃] (M = Gd (<b>1</b>), Dy (<b>2</b>), Er (<b>3</b>), Y (<b>4</b>)) using the redox-active iminopyridyl (L^•–) ligand exclusively, which possess the highest ratio of radicals to lanthanide reported for discrete metal complexes. Direct current magnetic susceptibility studies suggest that dominant antiferromagnetic interactions exist between the radical and lanthanide ions in all of the complexes, which is strongly corroborated by magnetic data fitting using a Heisenberg–Dirac–Van Vleck (HDVV) Hamiltonian (−2<i>J</i> Hamiltonian). A good agreement between the fit and the experimental magnetic data obtained using <i>g</i> = 2, <i>J</i>_rad‑rad = −111.9 cm^–1 for <b>4</b> and <i>g</i> = 1.99, <i>J</i>_rad‑rad = −111.9 cm^–1, <i>J</i>_Gd‑rad = −1.85 cm^–1 for <b>1</b>. Complex <b>2</b> shows frequency-dependent slow magnetization relaxation dynamics in the absence of an external magnetic field, while <b>3</b> shows field-induced frequency-dependent χ_M′′ signals. An ideal octahedral geometry around the lanthanide ion is predicted to be unsuitable for the design of a single-molecule magnet (SMM); nevertheless, complex <b>2</b> exhibits slow relaxation of magnetization with a record high anisotropy barrier for a six-coordinate Dy­(III) complex. A rationale for this unusual behavior is detailed and reveals the strength of the synthetic methodology developed

Carboxylate free mu-oxo bridged ferric wheel with a record exchange coupling

Ahmed N, Upadhyay A, Rajeshkumar T, et al. Carboxylate free mu-oxo bridged ferric wheel with a record exchange coupling. Dalton Transactions. 2015;44(43):18743-18747.A novel oxo-bridged, carboxylate free 'ferric wheel' was isolated with the molecular formula [Fe-8(III)(mu-O)(4)(L2-)(8)] (1). Magnetic susceptibility measurements suggest that the Fe(III) ions are coupled anti-ferromagnetically and magnetic data modelling yields J(1) = -26.4 cm(-1), J(2) = -170 cm(-1) which are rationalized by DFT calculation. The exchange value for 1 of -170 cm(-1) (Fe-O(oxo)-Fe) is the largest exchange value known compared to any homometallic or heterometallic wheel reported to date