Digera muricata (L.) Mart. mediated synthesis of antimicrobial and enzymatic inhibitory zinc oxide bionanoparticles

Herein, we report a simple and ecofriendly synthesis of ZnO nanoparticles (ZnO NPs) employing Digera muricata along with bioassay studies of synthesized NPs. The ZnO NPs obtained were indicated by a colour change from yellow to almost faint yellow giving whitish tinge and supported by the appearance of UV-Vis band at 373 nm and were characterized by using Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray (EDX), and scanning electron microscopy (SEM). The FT-IR spectrum confirmed the presence of biomolecules fabricated on ZnO NPs as indicated by the absorption bands at 1,378 for C–O cm−1, and ZnO NPs were also evident from the absorption bands at 440 and 670 cm−1, the former being the result of symmetric vibration of hexagonal ZnO and the latter belonged to a very weak vibration of ZnO. Its surface morphology was confirmed by SEM, and the zinc and oxygen bonds were confirmed by EDX analysis giving sharp signals for Zn and oxygen with At% of 17.58 and 30.49, respectively. The antimicrobial activity of ZnO nanoparticles was determined by the agar well diffusion method against pathogenic bacterial and fungal strains using imipenem and miconazole as standards. The results reflected that ZnO NPs enhanced the activity of plant extracts against all employed algal (E. coli, S. faecalis, P. aeruginosa, K. pneumonia, S. aureus, and B. subtilis) and fungal (T. mentogrophytes, E. floccosum, A. niger, M. canis, and F. culmorum) strains. The antibacterial and antifungal activities of extracts were enhanced by the formation of ZnO NPs. The results indicated that Digera muricata extract contains effective reducing agents for green synthesis of Digera muricata fabricated ZnO NPs, which are more potent antimicrobial than the plant extract and showed almost similar inhibition against lipoxygenase, i.e., the IC50 value of 83.82 ± 1.15, comparable to the standard.

Free Vibration Analysis of Symmetric Sandwich Beams

The aim of the present work is to study the linear free symmetric vibration of three-layer sandwich beam using the energy method. The zigzag model is used to describe the displacement field. The theoretical model is based on the top and bottom layers behave as Euler-Bernoulli beams while the core layer as a Timoshenko beam. Based on Hamilton’s principle, the governing equation of motion sandwich beam is obtained in order to calculate the linear frequency parameters. Two types of boundary conditions simple supported-simple-supported (SS-SS) and clamped-clamped (C-C) under the influence of materials properties and geometrical parameters are studied. The validation of results is done by comparing with another studies, which available in the literature and found good agreement between the studies.

Vibrational spectroscopic study of intensities and shifts of symmetric vibration modes of ozone diluted by cumene

In the current research, ATR–FTIR and FT–Raman spectroscopies was used to investigate the effect of concentration on IR and Raman intensities and shifts of symmetric vibration modes of Ozone diluted by Cumene. The symmetric vibration mode of Ozone was observed at IR and Raman shifts of 850 and 975 cm-1, respectively. By reducing the concentration of Ozone, its intensity also was reduced and the symmetric vibration mode of Cumene was observed at IR and Raman shifts of 1050 and 1185 cm-1, respectively. The concentration has not influence on IR and Raman shifts of vibration modes. The experimental results were confirmed the linear dependency of IR and Raman intensities to the concentration of sample.Ozone molecule (left illustration) and Cumene molecule (right illustration) (Santiago-López et al. 2010; Guevara-Guzmán et al. 2009; Pereyra-Muñoz et al. 2006; Foucaud et al. 2006; Elsayed 2001; van Hoof et al. 1997; Chrostowski et al. 1983; Boehme et al. 1992; Catalá et al. 2013; Balvers et al. 1992; Marker et al. 1986).

Towards an optofluidic pump?

Most of the vibrating mechanisms of optofluidic systems are based on local heating of membranes that induces liquid flow.We report here a new type of diaphragm pump in a liquid film based on the optical radiation pressure force. We modulate a low power laser that generates, at resonance, a symmetric vibration of a free standing soap film. The film lifetime strongly varies from 56 s at low power (2 mW) to 2 s at higher power (70 mW). Since the laser beam only acts mechanically on the interfaces, such a pump could be easily implemented on delicate microequipment on chips or in biological systems.

Research on Typical Vibration Accelerations of Wind Wheel Changing with Yaw Angle

Dynamic and static frequency of the rotor about diameter of 1.4m small horizontal axis wind turbine was tested by using PULSE16.1 structural vibration analysis system., through combining the data of static frequency to identify rotor Dynamic frequency using spectrum analysis method. The conclusions found that, at a yaw condition of constant rotor speed, vibration acceleration of axial movement, disc effect and first order vibration of rotor increased with the increase of the yaw angle. The reason was that yaw exciting force which generated by the yaw behavior increased with the increase of yaw angle. At a constant load yaw, vibration acceleration of axial float, disc effect increased with the increase of the yaw angle. At the yaw condition of constant load R=82Ω、R=118Ω and the yaw angle 25°,30°,the acceleration value sharp increased and occurred the machine resonance phenomenon due to the tower instability. First order symmetric and anti symmetric vibration acceleration of rotor decreased with the increase of the yaw angle. The reason was that after the wind turbine yaw, the speed decreased of rotor caused the centrifugal force of the blades decreased, the impact of the centrifugal load changed was far greater than yaw exciting force for the first order vibration acceleration. The study also found that vibration acceleration values of rotor first order anti symmetric was ​​greater than axial movement, disc effect and first order symmetric vibration acceleration values, which shows that stress concentration in root of blade was large and the blade fatigue damage was more serious. This paper related research results can provided a new analytical thinking for rotor fatigue damage or breakage occurred frequently in wind turbine operation process, and may provide a reference for the vibration characteristics of rotor in the process of yaw.

Effect of the Rudder on the Vibration Frequency of Wind Turbine

Based on the finite element theory, an analysis about the changing of rotor vibration mode of the wind turbine with and without rudder at static state, and a research was carried out to study the impact of the rudder on wind turbine vibration frequency during operation condition of a small horizontal axis wind turbine by using Ansys Workbench. The result showed that, rudder vibration mode was the coupling of rudder vibration mode and first order anti-symmetric vibration mode of rotor. With the increasing of rotating speed, wind turbine vibration frequency increased because of the stiffening effect caused by centrifugal force, and the difference of first order anti-symmetric vibration frequency and symmetric vibration frequency was decrease which was caused by the aerodynamic force. At the same time, the changing of the external load had no effect on the vibration frequency of rudder, the reason of that was counterweight of the rudder. When the rotor speed was in the resonance region, rudder vibration frequency was equal to first order anti-symmetric vibration frequency at the rotating speed n=10.91Hz, an obviously resonance phenomenon occurred. The related research could provide some theoretical guidance for the design of small wind turbine rudder.

Feeding Submillimeter Microparts Along a Saw-Tooth Surface Using Only Horizontal Vibration: Effects of Saw-Tooth Pitch, Vibration Frequency, and Humidity

We previously showed that microparts can be fed along a saw-tooth surface using simple planar symmetric vibration. Microparts move forward because they adhere to the saw-tooth surface more backward than forward. We studied also the effects of saw-tooth pitch and vibration frequency on the movement of 2012 capacitors (2.0 × 1.2 × 0.6 mm, 7.5 mg). In the present work, we studied the movement of smaller 0603 capacitors (0.6 × 0.3 × 0.3 mm, 0.3 mg) compared to larger capacitors. We also measured the effect of ambient humidity on smaller capacitors, finding that feeding was fasted when the pitch was 0.05 mm. Smaller capacitors moved more slowly than larger ones because smaller ones were more affected by adhesion. Feeding velocity of smaller capacitors was thus affected greatly by ambient humidity.