In-plane Bending Vibrations Research Articles

Experimental modal analysis of in-plane bending vibration mode using actual water main network

Accidents of water leakage and bursting due to deterioration of water pipes cause water outages and economic losses in the surrounding areas. We are conducting research to develop measurement and diagnostic methods for buried water pipes. The graphitic corrosion of water pipes in a buried environment causes a reduction in pipe thickness which leads to strength problems. For this reason, methods for detecting pipe thickness are necessary for evaluating pipe deterioration, however, there is no effective way to analyze pipe thickness today because it cannot be visually observed in a buried environment. In this study, we focused on the shift in eigenfrequencies of in-plane bending vibration of rings due to deterioration. At first, we performed an experimental modal analysis by using a water pipe network which is used in a practical water utility. In addition, we conducted a theoretical analysis based on a model of a two-dimensional ring with coupled incidental attachment. As a result, in-plane bending vibration was observed in the water pipe of actual size. Furthermore, in-plane bending vibration was observed when excited through fire hydrants and it is also observed in pipes that are different material and diameters.

Prototyping of vibration-sensing-actuation device which is contained high-power electrodynamic speaker for diagnosis of actual water main network

Water leakage and bursting due to deterioration of water distribution mains lead to water outages and economic losses. To prevent the accidents, we are conducting research to develop measurements and diagnostic methods for buried water mains. In this study, we focused on the shift in eigenfrequencies of in-plane bending vibration of rings because of deterioration. Therefore, we are developing the vibration-sensing-actuation device which detects the frequency changes of in-plane bending mode. The water distribution network is mainly composed from cast iron pipe. Moreover, the attached facilities for example fire hydrant and water valve are contained. Since attached facilities are fabricated from cast iron component, actual water main network is heavy facilities which have high rigidity. In order to excite the desired in-plane bending mode in heavy components, the proposed sensing-actuation device requires the high-power actuator. In this study, we introduce the high-power electromagnetic actuator more than 100W output into the proposed device. Furthermore, the fundamental operational tests were conducted under the various input signals in the laboratory situations. In addition, the field operation confirmation was performed in an actual water main network.

Thermally stable and anti-corrosive polydimethyl siloxane composite coatings based on nanoforms of boron nitride

Coating technology has been emerged as a recognized and cost-effective approach in regard to mitigating issues that are linked to corrosion. We employed in-house synthesized boron nitride nanosheets (BNNS-CVD) and commercially available nanosized boron nitride (BN-nano) as fillers in this study to fabricate composite coatings with enhanced thermal stability and corrosion resistance. These fillers were dispersed in polydimethylsiloxane (PDMS) resin to develop composite coatings. The Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and electrochemical impedance spectroscopy (EIS) were employed to characterize the prepared composite coatings. The FTIR analysis revealed a prominent absorption band around 1350 cm−1 that is indication of the distinctive B-N in-plane bending vibrations characteristic of boron nitride (BN). The FESEM images simultaneously confirmed the sheet-like morphology of both BN-nano and BNNS-CVD, which both found to be uniformly dispersed in the PDMS matrix. The EIS revealed that the composite films based on BNNS-CVD exhibited superior corrosion resistance compared to those based on BN-nano when exposed to a 3.5 wt% NaCl solution. Further, TGA profiles indicated that the composite films maintained their structural integrity up to 200 ℃ without degradation. Therefore, thermally stable and corrosion resistant coatings can be valuable for various new technology applications that involve corrosion issues.

Study of the Molecular Structure, Spectroscopic Analysis, Electronic Structures and Thermodynamic Properties of Niacin Molecule Using First-principles

This work describes the different properties of Niacin's molecule using the density functional theory (DFT) B3LYP/6-311++G (d, p) basis set. The optimized energy for the Niacin molecule is -436.987 Hartree. The peak values from FT-IR spectra show the C=C, C-C vibrations, C-H stretching vibrations, C-H in-plane bending vibration, C-H out-of-plane bending vibration, C-O stretching vibration, C-N vibration and O-H vibration. The MEP and ESP analyses indicate that the oxygen and nitrogen atoms exhibit nucleophilic regions, while the hydrogen atoms exhibit electrophilic regions. The energy gap of the Niacin molecule is found to be 5.398 eV through HOMO-LUMO analysis. The electronegativity value of 4.847 eV signifies the molecules ability to attract electron and the calculated value of chemical hardness is 2.7 eV which reflects the molecular stability. The softness value of 0.370 eV-1 denotes the molecule polarizability. Also the chemical potential value is -4.847 eV which represent the ability to donate or accept electron. Similarly, electrophilic index with value 4.351 eV shows the electrophilic behavior that signifies its capacity to accept electron. Because of the larger energy gap, the molecule becomes hard and hardness is greater than softness. In this molecule, the C2 atoms have the highest positive charge along with C3 and all the hydrogen atoms, while C1 has the highest negative charge together with some negative charge on C4, C5, N6, C11, O12 and O13 atoms. When the temperature rises, the thermodynamic parameters such as heat capacity at constant volume and pressure, internal energy, enthalpy, and entropy increase, but Gibbs free energy decreases.

Study of the Spectroscopic Analysis, Electronic Structure and Thermodynamic Properties of Ethyl benzene Using First-Principles Density Functional Theory

This study describes the optimized molecular structure, spectroscopic analysis, electronic structure and thermodynamics properties of the ethylbenzene molecule using first-principles DFT/B3LYP method with 6-311++G(d,p) basis set. The C-H in-plane bending vibration is observed between 1400 and 1050 cm-1, while the C-H out-of-plane bending vibration is observed between 1000 and 675 cm-1. The benzene ring has the most negative potential that corresponds to the attraction of proton due to concentrated electron density while the moderate positive potential is localized closed to the hydrogen atom. Analysis of the HOMO and LUMO in ethylbenzene anticipates an energy disparity of 6.3028 eV, a value closely matching the energy gap derived from DOS calculations. Mulliken charge analysis of the ethylbenzene molecules gives the information that all the hydrogen atom corresponds to the positive charges while all the carbon atom except C3 corresponds to the negative charge and the values of the global parameters such as hardness, chemical potential, electronegativity, electrophilicity index, softness are found to be 3.1514 eV, -3.5979 eV, 3.5979 eV, 2.0538 eV and 0.3173 eV-1 respectively. Various thermodynamic parameters such as heat capacity at constant volume, heat capacity at constant pressure, total internal energy, enthalpy and entropy, exhibit a rising trend with increasing temperature whereas Gibbs free energy shows an inverse relationship with temperature variation.

A computational characterization of N-heterocyclic carbenes for catalytic and nonlinear optical applications

Abstract Very recently, N-heterocyclic carbenes (NHCs) have found a wide range of applications in the fields of catalysis and nonlinear optics. Herein, we have employed 1,3-bis-(1(S)-benzyl)-4,5-dihydro-imidazol-based carbene as a reference molecule and substituted one H atom from each CH2 of the benzyl groups in both sides by CH3, NH2, and CF3 to study the thermodynamic and opto-electronic properties of NHCs theoretically. It was observed that the enthalpy (H), Gibb’s free energy (G), specific heat capacity (C v), and entropy (S) increase significantly in the presence of the electron-withdrawing groups compared to the electron-donating groups. The IR active in-plane bending vibrations of the CH (NHC) group are shifted to the higher frequency region for the considered substituted molecules compared to the reference carbene. The analysis of the electronic properties shows that the CH3-substituted carbene is more reactive for catalytic activities compared to other NHCs. The calculated nonlinear optical (NLO) properties reveal that the NH2-substituted NHC has the largest hyperpolarizability value whereas the CH3-substituted NHC has the largest dipole moment and polarizability among all, making them potential candidates for the development of NLO materials.

In-plane bending vibration of L-shaped cantilever nanobeams carrying a tip nanoparticle by nonlocal elasticity

In-plane bending vibration of L-shaped cantilever nanobeams carrying a tip nanoparticle by nonlocal elasticity

Comparative Computational Study on Molecular Structure, Electronic and Vibrational Analysis of Vinyl Bromide based on HF and DFT Approach

In this study, we have used the Hartree-Fock and Density Functional Theory method of calculation and compared the equilibrium configuration, electronic and vibrational mode of Vinyl Bromide molecule. The molecule is geometrically optimized initially by using 6-31G basis set with B3LYP functional and then bond angles, bond lengths, dihedral angles and IR spectra are compared respectively. Various groups of atoms in Vinyl Bromide molecule by DFT has more accurate bond length, bond angle values rather than by HF computation when comparing with the experimental values. The ground state energies are found at angle 10° or 180° or 360° using HF and DFT method of calculation for the H4-C1-C2-Br6 position. Values of the carbon-hydrogen, carbon-carbon and carbon-bromine bond lengths and bond angles for optimization state of C2H3Br molecule using Hartree-Fock and Density Functional Theory methods with respect to the basis set 6-31G have been analyzed. The C−H in-plane bending vibration and C−H out-of-plane bending vibrations occur in the region 1400–1050 cm-1 and 1000–675 cm-1 respectively. The electronic properties, such as Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital energies are performed by HF and DFT approach and the difference in Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital energy gap for HF and DFT method are 14.0847 eV and 6.8994 eV respectively

Rod-Shaped Linear Inertial Type Piezoelectric Actuator

This article presents a numerical and experimental investigation of a novel rod-shaped linear piezoelectric actuator that consists of a square cross-section-shaped rod with eight piezo ceramic plates and a cylindrical guidance rail. The rod has a hollow cut made with an offset from the longitudinal axis of the symmetry. A cylindrical guidance rail is placed on one side of the rod, while T-shaped clamping is formed on the opposite side. The slider is mounted on the rail and is moved along it. The actuator is compact, making it possible to mount it directly on a printed circuit board (PCB) or in another device with limited mounting space, restricted mass, or actuator footprint. The operation of the actuator is based on the excitation of the first longitudinal vibration mode of the rod that induces in-plane bending vibration of the nodal zone of the rod due to a hollowed cut asymmetrically placed in the central part of the actuator. The actuator is driven by two sawtooth waveform electric signals with the phase difference of π that allows exciting longitudinal deformations of the rod and controls the reverse motion of the slider. The results of numerical investigations confirmed the operation principle of the actuator at the frequency of 59.72 kHz. The maximum displacement amplitude of the guidance rail in the longitudinal direction reaches up to 152.9 μm while the voltage of 200 Vp-p was applied. An experimental investigation of the actuator was made, and a maximum linear speed of 45.6 mm/s and thrust force of 115.4 mN was achieved.

Free in-plane bending vibration of flexible L-shaped nanostructures based on the nonlocal beam theory

Free in-plane bending vibration of flexible L-shaped nanostructures based on the nonlocal beam theory

The proliferation and colonization of functional bacteria on amorphous polyethylene terephthalate: Key role of ultraviolet irradiation and nonionic surfactant polysorbate 80 addition

Environmental pollution with plastics including polyethylene terephthalate (PET) has become a severe global problem, especially microplastic pollution, which is acknowledged as an emerging global pollutant. Biodegradation as a feasible and promising method has been studied, while colonization as the initiating step of the degradation process has seldom been studied. Here in this paper, we explored for the first time the key role of ultraviolet (UV) irradiation and nonionic surfactant polysorbate 80 (Tween-80, 0.2% V/V) in the proliferation and colonization of three functional bacteria (Pseudomonas putida, Pseudomonas sp. and Paracoccus sp.) on amorphous PET (APET). We found that 25 days of UV irradiation can trigger photolytic degradation process (appear the stretching vibration of associating carboxyl end group and the in-plane bending vibration of -OH) and introduce oxygen-containing functional groups on the surface of APET, even though the hydrophobicity of APET was scarcely changed. With regard to Tween-80, it can be utilized by these bacteria strains as carbon source to promote the proliferation, and it can also improve the cell surface hydrophobicity to stimulate the bacterial colonization during the first ten days of the experiment. When UV-irradiation and Tween-80 were provided together, the former factor can provide the target sites for functional bacteria to colonize, and the later factor can provide more candidates waiting to colonize by stimulating proliferation. As a result, an even better proliferation and colonization result can be achieved through the synergistic effect between the two factors. To some extent, the exposure between potential degrading bacteria and substrates to be degraded can be increased, which will create conditions for degrading. Generally, this research can provide certain theoretical basis and technical guidance for the remediation of plastic-polluted soil and the ocean.

Validation of potential energy distribution by VEDA in vibrational assignment some of β-diketones; comparison of theoretical predictions and experimental vibration shifts upon deutration

The harmonic vibrational frequencies of the cis-enol forms of some of β-diketones with different substitution in beta position, vis. H, CH3, and Ph ring, as the symmetric and asymmetric molecules, were calculated using density functional theory (DFT) at the B3LYP/6–311++G(d,p) level of theory. The results of DFT calculations were used to obtain the potential energy distribution (PED) by VEDA software. The PED results compared with the Gauss View animation, as our reassignments, and the experimental IR shifts upon deuteration of hydrogen in the OH and CHα. According to our study, the PED contributions, Gauss View animation and observed shifts show similar results for most of the bands which are not coupled with the OH and/or CHα bending, such as asymmetric and symmetric CH3 stretching and in-plane deformations, CH3 rocking vibrations and 8a, 19b, 9a, 15, 18a, and 12 motions of the phenyl ring. The largest discrepancies were observed in the 1700-1000 cm−1 region, likely due to the coupling with the OH and CHα in-plane bending vibrations, such as νaC = C–C = Ο, νsC = C–C = Ο and δOH. Furthermore, the calculated PED contributions by VEDA software do not well define the vibrational contributions to those groups in the molecule that are directly involved in the intramolecular hydrogen bond and the observed failure of the VEDA procedure is possibly due to inappropriateness of the default options.

Multifactor-controlled mid-infrared spectral and emission characteristic of carbonate minerals (MCO3, M = Mg, Ca, Mn, Fe)

Carbonate minerals have been playing an important role in determining the history of the earth's atmosphere, geology, and hydrology and have received extensive attention. In this study, infrared spectral characteristics and infrared radiation properties of four carbonate minerals (calcite, rhodochrosite, siderite, magnesite) were highlighted and investigated by using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), energy dispersive X-ray spectrometer (EDS), differential scanning calorimeter (DSC) and infrared spectroscopy (IR) (absorption and emission spectroscopy). Infrared absorption and thermal emission spectra systematically illustrated the effect of cations (Ca2+, Mg2+, Fe2+, Mn2+) on shifting the positions and infrared performance of the carbonate absorption bands. Three specific modes of the carbonate anion (CO32−) in mid-infrared range, derived from the out-of-plane bending, asymmetric stretching, and in-plane bending vibration (ν2, ν3, and ν4 modes, respectively) were found to be blue-shifted with the decrease of cationic radius, bond length and lattice volume. The average emissivity of calcite, rhodochrosite, siderite, and magnesite were calculated as 0.954, 0.934, 0.907, and 0.883, respectively, in the temperature range of 50–155 °C and the mid-infrared range of 400–2000 cm−1. Emissivity and thermal radiation performance of carbonate minerals can be influenced by several interplaying factors. In particular, higher emissivity was proportional to longer bond length (cation-oxygen and carbon–oxygen with linear correlation coefficients (R2) of 0.751 and 0.721, respectively) and larger cationic radius (R2 = 0.872), which gave rise to lower vibrational frequency, narrower vibration range, and reduced absorbed energy. Furthermore, the heat capacity of four minerals presented a positive correlation with their infrared radiant energy within the temperature. It thus can be concluded that complex and multifactor interactions occur within the crystal structure affecting the fundamental vibrational frequencies of CO32− group, and infrared performance was consequently influenced. This paper can provide theoretical reference for demonstrating the effect of crystal structure on infrared radiation performance and spectral characteristics of various minerals, which is conducive to distinguish minerals based on their features in infrared spectroscopy.

Theoretical modeling and experimental investigation of a V-shaped traveling wave piezoelectric transducer for ultrasonic cavitation Peening: Part A

Ultrasonic cavitation peening is a surface enhancement technology that can increase surface hardness without obviously introducing a high surface roughness of the treatment surfaces. However, the most commonly used traditional transducers for ultrasonic cavitation peening are operated in the longitudinal mode and generate a standing wave in the working gap between a sonotrode end and a treated surface, causing a small cavitation treated area and low efficiency for treating the axis components. To achieve a high efficiency on the surfaces of axis components, a new V-shaped traveling wave transducer is proposed in this paper. Two Langevin transducers are employed to couple on the ring sonotrode, generating two third order in-plane bending vibrations with a spatial phase difference of 90° in the ring. Therefore, same elliptical vibrations are generated in all points on inner surface of the ring, resulting in a uniform cavitation effect around the axis component which is located in the center of the ring sonotrode. It is the first time to propose that cavitation bubbles are generated utilizing traveling waves. An analytical model is created utilizing the transfer matrix method for the vibrating system to describe the dynamic behavior and predict the acoustic field of the working area in the ring sonotrode. To validate the developed transfer matrix model, experimental investigations were conducted to measure the vibration characteristics of the proposed transducer and compared to the transfer matrix model calculation results. For further proving the feasibility of the cavitation peening, sonochemiluminescence was carried out to evaluate the distribution of cavitation bubbles in the working area. The results show that calculation results have a good agreement with the experimental results and a higher voltage and smaller working gap were beneficial for the ultrasonic cavitation treatment utilizing this novel transducer.

Analysis of the in-plane bending vibrations of cylindrical shells subjected to white noise excitation through a connecting tube

Analysis of the in-plane bending vibrations of cylindrical shells subjected to white noise excitation through a connecting tube

Experiment of in-plane bending vibration of thin cylindrical shell in buried situation

Experiment of in-plane bending vibration of thin cylindrical shell in buried situation

Enhanced photophysical properties of silica-methylene blue@amorphous carbon as fluorochromes with modulated Raman-active vibration modes

As a kind of near-infrared dye, methylene blue (MB) molecule is proneness to form excimers in solid powder or solution at high concentration, which results in weak photoluminescence intensity during clinic diagnostic and cell labeling applications. Aiming to improve the quantum yield of MB, silica-MB particles are herein prepared and treated hydrothermally (HT) to synthesize silica-MB-HT and silica-MB@amorphous carbon with glucose as carbon source (silica-MB@AmC). Significantly, hydrothermal treatment causes destruction of Si-O-Si network, modulation of aggregation state, variations of energy gap and release behavior of MB. In comparison with that of silica-MB, emission intensities of both silica-MB-HT and silica-MB@AmC increase greatly and their photoluminescence peaks are blue-shifted, which are closely related with Raman-active vibration modes of MB in a locally-excited state. Enhanced emissions of both silica-MB-HT120 and silica-MB@AmC120 are observed with increased intensities of Raman peaks assigned to in-plane bending vibrations of CH bond during skeletal deformation of CC in ring. In contrast, the in-plane bending vibration for CH bonds at end group of MB is considered as a way of radiation decay, and strong vibration of this Raman-active mode causes weak emission intensities of silica-MB-HT180 and silica-MB@AmC160. The stabilities of photophysical properties are compared after 72 h of incubation in buffered mediums or 5 h of illumination under ultraviolet light. The photoluminescence intensity of silica-MB@AmC120 fluorophore increase remarkably after illumination, meeting the requirements of reduced photobleaching, minized solvatochromic shift and increased fluorescent efficiency during versatile applications.

A study on the modification of azole rings to regulate the transition dipole moment, MLCT and T1 structural distortion of 2-pyridyl-azole copper (I) complexes for high phosphorescence performance

Heterocyclic ligands based on 2-pyridyl-azole, have become some of the ideal ligands for metal complexes due to their flexible structure and wide wavelength tunability. In this paper, a series of Cu(N∧N) (P∧P) complexes are studied by density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The results indicate that the combination of incorporation of N atoms and substitution of electron donor-acceptor groups can effectively control the type and the proportion of the lowest triplet states (T1) phosphorescent transition. A higher matching degree between the effective spin-orbit coupling (SOC) matrix elements and the transition dipole moments (The Sn state has both effective SOC and large transition dipole moments of Sn→S0 transition) brings about a larger transition dipole moment MTa of T1a→S0 transition, and further results in the fastest radiative decay rate (kr) for complex 2, although the main transition of which is internal-ligand charge transfer (ILCT). In addition, the non-radiative decay rate (knr) of complex 2 is lower than other complexes of series 3 (the reorganization energy produced by in-plane bending vibration of C–H bond in six-membered ring is larger than complex 2), so this complex has the highest quantum yield. Overall, the above analyses illustrate that despite the participation of Cu(I) in transition as an indispensable factor for the radiative transition, the higher component ratio does not necessarily lead to a faster kr. In addition, it is also essential to have a well-matched large transition dipole moments of the singlet states Sn→S0 transition involved in the effective SOC. Consequently, in the development of the 2-pyridyl-azole Cu(I) luminescent materials, the high quantum yield materials can be designed by adjusting the substituent at C3 position and the strength of electron donor-acceptor groups at C5 position to balance the charge transfer transition modes.

Structural change of trans-azobenzene crystal and powder under high pressure

Structural changes in the trans-azobenzene single crystal and powder upon compression realized by a diamond anvil cell (DAC) were disclosed via the analysis of Raman spectroscopy. Compared to the shearing force that destroys the crystal structure of trans-azobenzene, the hydrostatic pressure makes the crystal structure of trans-azobenzene stacking more closely and orderly, which are proved by the blue-shifts of Raman bands. During the compression process, the peaks at 1159, 1182 and 1593 cm−1, highly related to C–H in-plane bending, C–C stretching and in-plane bending vibrations of benzene ring, show more obvious blue-shifts Δ = 21, 35 and 21 cm−1, respectively. Two types of trans-azobenzene under hydrostatic pressure display different spectral behaviors, due to the strong intermolecular interactions in their crystal forms, but not in powder. When the pressure was gradually reduced to the ambient pressure, the initial forms of the Raman spectra of trans-azobenzene were entirely recovered, indicating that the pressure-induced structural changes are reversible in a certain pressure range. Our spectroscopic observations enable a deeper understanding of the molecular interactions of azobenzene compounds.

Theoretical and experimental investigations of nitropyrene on silver for nonlinear optical and metal ion sensing applications

Adsorption of nitropyrene (NPy) on silver has been analysed through theoretical and experimental techniques. Using density functional theory (DFT), variations in geometrical parameters were identified in regions of NPy near the silver cluster. Theoretical investigations on the plot of molecular electrostatic potential (MEP) and its charges, Fukui calculations and the overlap of natural bond orbitals(NBO) confirm charge transfer from silver to NPy. Using XRD technique, the average crystallite size of the NPy-Ag NPs has been calculated as 18.4 nm. The UV–Vis spectra of the investigated systems have been simulated theoretically and observed experimentally. Nonlinear optical (NLO) behaviour of NPy-Ag is predicted by theoretical studies and confirmed experimentally using the open aperture Z-Scan technique. Downshifting of theoretical and experimental C–N and NO2 stretching vibrational modes together with the additional in-plane CH bending vibrations of NPy-Ag strongly confirms the process of adsorption. Using calorimetric detection based on the plasmonic response of NPy-Ag NPs, a sensing mechanism for mercury ions is proposed based on both theoretical and experimental results. The study indicates that NPy-Ag NPs is a promising candidate for NLO and sensor devices.