DFT Study on the Substituent Effect of Anticancer Picoline-Diazido-Pt(IV) Compounds

The geometric structure of azido Pt(IV) compounds containing picoline was calculated by using density functional theory(DFT) at the LSDA/SDD level. The ESP distribution shows the possible reaction sites of the compounds. In addition, the frequency calculation results assigned the infrared spectra of these compounds, and specified important stretching and bending vibrations. The HOMO-LUMO energy gaps of these compounds are also calculated to explain the charge transfer of the molecules. The distribution of Mulliken charges and natural atomic charges of these atoms is also calculated. Natural bond orbital(NBO) analysis explains the intramolecular interactions and their electron density.

Overtone Frequencies of NO2 using Lie algebraic model

In this paper, we used the one dimensional unitatry Lie algebraic model to compute the vibrational frequencies of nitrogen dioxide (NO2) molecule in the gas phase up to the sixth overtone. In this model, the Hamiltonian operator describes the stretching and bending vibrations with algebraic parameters. The calculated fundamental vibrational frequencies are compared with experimental values and results consistent with the reference values.

Dielectric spectroscopy of aluminum oxide (γ-Al2O3)

Aluminum oxide (Al2O3) are continuously demonstrating the functional characteristics in devices. The physiochemical properties of hydrothermally as-grown Aluminum oxide (Al2O3) have been investigated in this research article. The as-prepared material was confirmed as γ- phase formation of Al2O3. The average crystallite size was found ∼ 78 nm, whereas the particles were found in nano scale too. Moreover, the absence of impurity in EDS analysis, and the presence of the bending vibrations of Al-O-Al and Al-O band in FTIR characterization further confirmed the absence of impurity in the material. Evaluated dielectric properties such as a relatively high dielectric constant, and low dielectric loss indicated the good optical quality of γ- Al2O3. Impedance and modulus spectroscopic studies showed the non-Debye type relaxation in γ- Al2O3 with an average relaxation time of 5.8 μs. Overall, the dielectric spectroscopy analysis of γ- Al2O3 indicates the promising applications of γ- Al2O3 in devices as dielectrics.

Optimal deployment of the spoke of a largesized transformable reflector according to the hierarchy of criteria

The article discusses the process of controlling the angular motion of the spoke of a large-sized space-based reflector, taking into account bending vibrations. Currently, large antennas are actively used for receiving and transmitting data. When launching large structures into space, the problem arises of reliably deployment the spokes, since they are packed in a small volume to be able to be installed in a launch vehicle. Due to the possibility of various abnormal situations, such as jamming of elements, engagement of the net, it is necessary to re-deployment the antenna. Therefore, it is important to develop control algorithms that can reliably solve the problems of direct and reverse motion. In the process of deployment and bringing together the elements of the reflector, various deformations appear in the structure. When the antenna spokes are brought together, lateral oscillations make the largest contribution to the oscillatory of the transient process. Currently, elastically deformed elements are used to deployment large-sized reflectors, and a control program is also used. This prevents the control from being adjusted when the deployment conditions change. The paper investigates the possibility of minimizing the vibrations of a structure during its deployment by using optimal control algorithms in real time. The forward and reverse motion of the antenna elements is performed by means of a two-criteria hierarchy optimization. The results of numerical simulation of the optimal rotation of the reflector spoke are presented. The proposed algorithm allows you to choose the optimal control in emergency situations for various types of large reflectors.

Nonuniformity of Isometric Properties of Automotive Driveshafts

This paper presents an analysis of the CVJ (constant velocity joint) of automotive driveshafts from a point of view concerning the nonuniformity of isometric properties. In the automotive industry, driveshafts are considered to have constant velocity through its joints: free tripode joints and fixed ball joints, which has been proved by Mtzner’s indirect method and Orain’s direct method for tripod joint. Based on vectorial mechanics, the paper proved the quasi-isometry of velocity for polypod joints such as fixed ball joints. In the meantime, it was computed that the global nonuniformity of constant velocity joints for modern driveshafts based on the Dudita-Diaconescu homokinetic approach for the driveshafts. The nonuniformity of the velocity isometry of driveshafts was computed as a function of the input angular velocity of the driveshaft, angular inclination between the tripod–tulip axis and the midshaft axis and the angular inclination between the bowl axis and midshaft axis. The main aim of this article is how to improve the geometric and kinematic approach to add an important correction when designing the driveshaft dynamics prediction such as: forced torsional vibrations, forced bending–shearing vibrations, and coupled torsional–bending vibrations for the automotive driveshaft in the regions of specific resonances such as principal parametric resonance, internal resonance, combined resonance, and simultaneous resonances. By the way it is added, there are important corrections for the design of driveshafts, for the torsional dynamic behavior prediction, and for bending–shearing dynamic behavior of the driveshafts in the early stages of design. The results presented in the article represent a starting point for future research on dynamic phenomena in the area mentioned previously.

Waste glass: An excellent adsorbent for crystal violet dye, Pb2+ and Cd2+ heavy metals ions decontamination from wastewater

The suitability of waste glass as an eco-friendly adsorbent for the removal of crystal violet (CV) dye, Pb2+ and Cd2+ heavy metal ions in waste water samples was investigated in batch mode. Waste glass sample was pulverized and characterized by SEM/EDX, XRD, BET and FTIR. Effects of variation in temperature, pH, contact time and recyclability of the adsorbent were studied. FTIR spectra revealed major peaks around 491.53 and 3444.12 cm-1 corresponding to the bending vibrations of Si-O-Si and -OH groups respectively. SEM/EDX analysis showed a dense, coarse, porous morphology with predominantly silica component. The effective surface area and size of the adsorbent were 557.912 m2/g and 2.099 nm respectively. Increase in temperature, dosage, contact time resulted in increase in adsorption efficiency. Optimum adsorption efficiency of 94%, 97.5% and 89.1% was attained for Pb2+ , Cd2+ ions and CV dye respectively at 70?C. Adsorption process followed more accurately pseudo-first order model and isotherm fitted perfectly into Freundlich model indicating a multilayer adsorption mechanism for CV dye and the heavy metals. 89.87% reduction in Chemical Oxygen Demand (COD) level of wastewater was reported upon treatment with waste glass adsorbent affirming its efficiency for dye and heavy metal pollutants removal.

Application of Elastic Fastenings of Equipment to Increase Vibration Frequency of the Wagon Body

Improving dynamic performance is a priority when designing new rolling stock. The frequency of natural bending vibrations of the body is one of the most important standardised indicators, a preliminary assessment of which allows obtaining optimal body designs.The objective of the work is to assess the prospects for the use of elastic fastenings of equipment to increase the natural vibration frequency of wagon bodies of suburban electric trains. Calculations were based on the finite element method and block Lanczos method. It is shown that it is advisable to use the rigid area tool and linearly elastic finite elements to calculate the frequencies in the simulation. The main ranges of fastening stiffness are highlighted, where the effect of using elastic supports is different. It is proposed to determine the stiffness of fastenings according to a given vibration frequency of the equipment. When the equipment is rigidly attached, the relative mass of the equipment does not affect the body bending vibration frequency. With elastic fastening, a greater effect can be achieved with a larger relative weight of the equipment. The effect of using resilient mounts increases with heavier equipment located closer to the centre of the body.It is shown that the effect of shear admittance of fastenings on the body vibration frequency is within 1 % and may not be considered in the simulation. In the considered example of a wagon body of a suburban electric train, the use of elastic supports allows an increase in the frequency of oscillations of the body by 3–10 %.

First-principles interpretation of electron transport though single-molecule junctions using molecular dynamics of electron attached states

The electron transport through the single-molecule junction of 1,4-Diaminobenzene (BDA) is modeled using ab initio quantum-classical molecular dynamics of electron attached states. Observations on the nature of the process are made by time-resolved analysis of energy differences, non-adiabatic transition probabilities and the spatial distribution of the excess electron. The role of molecular vibrations that facilitate the transport by being responsible for the periodic behaviour of these quantities is shown using normal mode analysis. The results support a mechanism involving the electron's direct hopping between the electrodes, without its presence on the molecule, with the prime importance of the bending vibrations that periodically alter the molecule{electrode interactions. No relevant differences are found between results provided by the ADC(2) and SOS-ADC(2) excited state models. Our approach provides an alternative insight into the role of nuclear motions in the electron transport process, one which is more expressive from the chemical perspective.

Determination of Prestress in Circular Inhomogeneous Solid and Annular Plates in the Framework of the Timoshenko Hypotheses

Determination of prestress fields in structures is of the utmost importance, since they have a significant impact on operational characteristics, and their level and distribution must be strictly controlled. In this paper, we present modeling of bending vibrations of solid and annular round inhomogeneous prestressed plates within the framework of the Timoshenko hypotheses. New inverse problems of prestress identification in plates are studied on the basis of the acoustic response subjected to some probing load. To solve direct problems on calculating oscillations and amplitude-frequency characteristics, a computational Galerkin-method-based scheme has been developed. In order to treat the inverse problems, we use a special projection approach based on the constructed weak problems statements, which makes it possible to determine the desired characteristics in the given classes of functions. The developed techniques for solving direct problems are implemented in the form of software packages realized via Maple. For both solid and annular plates, we estimate the sensitivity of the amplitude-frequency characteristics the values of which are used as the additional data in the inverse problems to a change in the prestress level; we conclude that the most favorable frequency range should be selected in the resonance vicinity. We have conducted a series of computational tests on reconstructing the plate’s prestresses of various levels and distribution patterns (decreasing, increasing, sign-changing laws). The results of computational tests revealed that the technique developed allows for the determination of the prestresses with a low error for two cases: when the cause of prestress formation and its type are known and when arbitrary prestress changing laws are considered.

Near-Infrared Spectroscopy Study of Serpentine Minerals and Assignment of the OH Group

Three different kinds of serpentine mineral samples were investigated using Fourier transform near-infrared spectroscopy (FTNIR). The results show that there are obvious differences in the characteristic infrared spectra of the three serpentine group minerals (lizardite, chrysotile, and antigorite), which can easily be used to identify these serpentine minerals. The combination of weak and strong peaks in the spectrum of lizardite appears at 3650 and 3690 cm−1, while the intensities of the peaks at 4281 and 4301 cm−1 (at 7233 and 7241 cm−1, respectively) are similar. A combination of weak and strong peaks in chrysotile appears at 3648 and 3689 cm−1 and at 4279 and 4302 cm−1, and a single strong peak appears at 7233 cm−1. In antigorite, there are strong single peaks at 3674, 4301, and 7231 cm−1, and the remaining peaks are shoulder peaks or are not obvious. The structural OH mainly appears as characteristic peaks in four regions, 500–720, 3600–3750, 4000–4600, and 7000–7600 cm−1, corresponding to the OH bending vibration, the OH stretching vibration, the OH secondary combination vibration, and the OH overtone vibration, respectively. In the combined frequency vibration region, the characteristic peak near 4300 cm−1 is formed by the combination of the internal and external stretching vibrations and bending vibrations of the structural OH group. The overtone vibrations of the OH stretching vibration appear near 7200 cm−1, and the practical factor is about 1.965. The near-infrared spectra of serpentine minerals are closely related to their structural differences and isomorphous substitutions. Therefore, near-infrared spectroscopy can be used to identify serpentine species and provides a basis for studies on the genesis and metallogenic environment of these minerals.