Ultrasonic Force Research Articles

Fabrication of Lipid Nanotubules by Ultrasonic Drag Force.

This work reports a new method of fabricating lipid nanotubules using ultrasonic Stokes drag force in theory and experiment. Ultrasonic Stokes drag force generated using a planar piezoelectric ultrasonic transducer in a remotely controllable way is introduced. When ultrasonic Stokes drag force is applied on lipid vesicles, the lipid nanotubules attached can be dragged out from the lipid film. In order to demonstrate the formation mechanism of the lipid nanotubules produced by ultrasonic drag force clearly, a theoretical kinetic model is developed. In the experiments, the lipid nanotubules can be rapidly and efficiently fabricated using this ultrasonic transducer both in deionized water and NaCl solutions with different concentrations. The stretching speed of the lipid nanotubules can reach 33 μm/s, approximately 10 times faster than that of the existing methods. The formed lipid nanotubules have a diameter of 600 ± 100 nm (>80%). The length can reach the millimeter level. This work provided a remotely controllable, highly efficient, high-velocity, and solution environment-independent approach for fabricating lipid nanotubules.

An experimental investigation on the effect of Al2O3/ cutting oil based nano coolant for Minimum Quantity Lubrication drilling of SS 304

Now a day's energy has the most important input for the growth of any system. Today energy demand has rapidly increased across all sectors, including agriculture, transport, residential, commercial and industry. To deal with these issues in many production processes, the effective cutting fluid pays an important role in reducing the friction force between the cutting tool and work piece surface. In this study we explore the experimental investigation to study the potential of Al2O3 Nano particles/Mineral oil-based cutting fluid during drilling of Stainless Steel 304 on tool life and the surface roughness. During investigation two step method is used to synthesis the Nano cutting fluid by using Al2O3 nanoparticles with volume fraction 0.3,0.8 and 1% in metal cutting fluid. Ultrasonic agitation force is used to achieve stability of Nanofluid. The Drilling operation on vertical CNC machine for 1000 rpm and 1500 rpm speed at constant feed rate of 0.050 mm/rev. Result shows that the Nano coolants increases the tool life and reduces the surface roughness. Tool life is observed highest for Nano cutting fluid of 1% volume fraction and achieve the lowest surface roughness 2.01 μm at 1000 rpm. The derived results are witnessing the usability of nano coolant.

Role of driven approach on the piezoelectric ozonation processes: Comparing ultrasound with hydro-energy as driving forces

Driven approach is vital for evaluating degradation and energy efficiencies of piezocatalysis process. Thus, piezoelectric ozonation processes driven by hydraulic (HPE-O3) and ultrasonic (UPE-O3) forces were compared systematically, using BaTiO3 as piezoelectric material for ibuprofen (IBP) degradation. The synergy indexes of HPE-O3 and UPE-O3 processes were 4.51 and 5.78, respectively. Besides, UPE-O3 process (88.84%) achieved better mineralization efficiency than HPE-O3 process (68.80%) in 90 min. Nevertheless, the energy consumptions of HPE-O3 process was only 4.01‰ of UPE-O3 process. The formation rate and concentration of •OH (the dominant active species in both processes) in UPE-O3 process were 2–3 times higher than that in HPE-O3 process. Notably, piezoelectric potential and current density driven by ultrasound were approximately 47500-fold and 40-fold than those by hydro-energy, respectively. These led to the difference of •OH paths between HPE-O3 and UPE-O3 processes. Further analyses indicated that •OH was mainly generated by single-electron transfer without H2O2 generation in HPE-O3 process, whereas both single- and double-electron transfer (with H2O2 generation) contributed to the production of •OH in UPE-O3 process. This study revealed the mechanism of piezoelectric ozonation process with different driven approaches and may provide valuable reference for selection of driven approaches in piezocatalytic study and application.

Nanostructural Arrangements and Surface Morphology on Ureasil-Polyether Films Loaded with Dexamethasone Acetate.

Ureasil-Poly(ethylene oxide) (u-PEO500) and ureasil-Poly(propylene oxide) (u-PPO400) films, unloaded and loaded with dexamethasone acetate (DMA), have been investigated by carrying out atomic force microscopy (AFM), ultrasonic force microscopy (UFM), contact-angle, and drug release experiments. In addition, X-ray diffraction, small angle X-ray scattering, and infrared spectroscopy have provided essential information to understand the films’ structural organization. Our results reveal that while in u-PEO500 DMA occupies sites near the ether oxygen and remains absent from the film surface, in u-PPO400 new crystalline phases are formed when DMA is loaded, which show up as ~30–100 nm in diameter rounded clusters aligned along a well-defined direction, presumably related to the one defined by the characteristic polymer ropes distinguished on the surface of the unloaded u-PPO film; occasionally, larger needle-shaped DMA crystals are also observed. UFM reveals that in the unloaded u-PPO matrix the polymer ropes are made up of strands, which in turn consist of aligned ~180 nm in diameter stiffer rounded clusters possibly formed by siloxane-node aggregates; the new crystalline phases may grow in-between the strands when the drug is loaded. The results illustrate the potential of AFM-based procedures, in combination with additional physico-chemical techniques, to picture the nanostructural arrangements in polymer matrices intended for drug delivery.

Study on formation mechanism and regularity of residual stress in ultrasonic vibration grinding of high strength alloy steel

The surface residual stress of the part has a crucial influence on its service performance. This paper studies the formation mechanism of residual stress in Ultrasonic Vibration Grinding (UVG) of high strength alloy steel, and obtains the correlation law between processing parameters and residual stress. First, based on the kinematics analysis of UVG, the formulas of ultrasonic grinding force and ultrasonic grinding transient moving heat source temperature field are analyzed. A thermal-mechanical coupled ultrasonic vibration grinding residual stress prediction model was established by FEM and verified by experiments. Second, the thermal behavior of the workpiece surface during UVG is analyzed, and the formation mechanism of the residual stress on the workpiece surface is explained. Finally, combining simulation and experimental results, a comprehensive correlation law between multiple grinding process parameters and residual stress is obtained. The research results show that compared with common grinding (CG), UVG can reduce the grinding temperature by about 8%. Both UVG and CG will reduce the original compressive stress on the surface, but UVG can make the surface of the workpiece retain greater compressive residual stress and prevent the emergence of tensile residual stress. This work of the thesis provides a basis for the research of residual stress in UVG.

Impact of sonication on slurry shear -thinning of protein from sea cucumber (Apostichopus japonicus): Proteolytic reaction kinetics, thermodynamics, and conformational modification

The present study investigated the effect of slit dual-frequency ultrasonic (SDFU)-shear thinning on the kinetics and thermodynamic mechanism of sea cucumber protein (SCP) substrate enzymatic proteolysis reaction. Acoustic cavitation and mechanical shear force applied reduced the protein particle size, intermolecular forces, surface charge and increased the average kinetic energies of the molecules which resulted in substrate viscosity reduction. The enzyme-driven bonds were thus exposed for easy protease accessibility to enhance the reaction rate (k) and reduce Gibbs-free (∆G) and activation energy (Ea) required. Substrate viscosity had a negative significant correlation (r = −0.865, p < 0.01) with SCP conversion degree. SDFU-pretreatment significantly boosted the reaction rate (ku) of enzymolysis at 20, 30, 40 and 50 °C by 63.0, 71.24, 37.5 and 37.22% respectively over the control (kc). Energy cost required for substrate conversion into product could be tremendously minimized by SDFU-pretreatment as affirmed by the lower values of enthalpy (∆H), entropy (∆S), and activation energy (Ea) (28.30 ± 0.63kJmol−1, −205.70 ± 1.72 Jmol−1 k−1 and 31.01 ± 0.27 kJmol−1 correspondingly) in comparison to the control. Higher cavitation yield and shear force from dual-frequency ultrasonication (20/68 kHz; sequential and simultaneous) resulted in significant modification in the α-helix (reduction), β-turn (reduction), β-sheet (increase), and random coil (increase) of SCP. The structural alterations shown in the circular dichroism (CD), intrinsic fluorescence spectra, scanning electron microscopy (SEM), surface hydrophobicity, and atomic force microscopy (AFM) of pretreated SCP exhibited the extent of modification caused by cavitation and ultrasonic shear force on enzyme-substrate interaction. Hence, ultrasonic-visco reduction can be applied by industries for enzymatic reaction process enhancement.

Construction of Ultrasonic Tactile Force Feedback Model in Teleoperation Robot System.

The ultrasonic phased array as an emerging interactive tool is increasingly used for aerial tactile interaction. However, there is almost no method to achieve remote variable force feedback through the ultrasonic phased array as far as we know. This article presents a force tactile feedback method for teleoperating robot systems that tracks the five fingers and forms a focus on the fingertips. First, the perceived size of the focus depends on the input parameters. The influence of the parameters on the physical output pressure intensity was obtained through physical test experiments. Then, the absolute threshold and difference threshold of human perception were studied through psychophysical experimental methods. Finally, the input parameters were selected according to the experimental results. According to the collected data, the construction of the force regression model was completed, and different parameters were mapped to the perceived intensity. The contact force generated in the actual operation is fed back to the haptic system, and the constructed model automatically adjusts the control parameters to ensure that the user’s hand presents a sensory output corresponding to the intensity change. The entire force feedback system is evaluated, and results show that the system shows good perceptual quality.

Повышение безопасности эксплуатации промышленных технических систем из композитных материалов путем прогнозирования их ресурса на основе новых методов неразрушающего контроля и глубинных нейронных сетей

The problem is considered related to increase of the operational safety of industrial facilities made of composite materials by means of an a priori assessment of the maximum service life. Two tasks are being solved: development of the new methods and means of non-destructive testing allowing to identify the defects that appear in the process of testing products with various loads and in the process of their operation; development of the new methods and means for assessing service life of the products based on the results of non-destructive testing. The first problem is being solved by the development of optical-thermographic non-destructive testing, including the technologies of ultrasonic thermotomography and electric force thermography, which determine the state of the object by dynamic temperature fields and optical control technology based on the fiber-optic sensors that measure the amount of material internal deformation under a force effect on the structure. Solution to the second problem is based on the use of neural network analysis (artificial neural networks) for assessment and prediction of the service life using the results of non-destructive testing with preliminary training of the neural network. An estimate was obtained by the experimental studies related to the error in determining the products service life, which is 12.6 %. The implementation of the proposed approach will allow to create the new technologies for predicting the service life of elements and structures made of composite materials using the results of non-destructive testing, which will provide an additional opportunity for developing practical recommendations on the confirmation or extension of the service life and improvement of safety for structures operation.

Understanding the relationship between particle size and ultrasonic treatment during the synthesis of metal nanoparticles

Ultrasonic treatment is an effective method for size refinement and dispersion of nanomaterials during their synthesis process. However, the quantitative relationship between ultrasonic conditions and particle size in the synthesis of metal nanoparticles has not been fully revealed. In this study, Cu nanoparticles were synthesized via the wet-chemical redox method under ultrasonic treatment, and statistical analysis on the evolution of particle size distribution was carried out. It was found that the particle size decreased exponentially with increasing ultrasonic power. A quantitative model was then proposed to describe the influence of ultrasonic power on the size distribution of metal nanoparticles from the perspective of the competition between the surface energy and the ultrasonic force. A relational expression of Rc∝γ47P-37 was revealed, and it was proved to fit well with the experimental results. Our study provides new experimental basis and theoretical method for understanding the mechanism of ultrasonic-induced size refinement of metal nanoparticles.

Analysis of Thickness Dependence of Nanoscaled Thin Film and Substrate by Ultrasonic Atomic Force Microscopy

Nanoscaled thin films are typically deposited on various substrates to achieve their unique characteristics. These thin film systems can be affected by the thickness variations between the thin film and the accompanying substrate. To investigate the thickness dependence of a nanoscaled thin film system, ultrasonic atomic force microscopy (Ultrasonic-AFM) which can evaluate the localized elastic modulus using the contact resonance frequency of a vibrating cantilever is applied. Copper thin films of low elastic modulus were deposited on silicon substrates of high elastic modulus. By contrast, Si3N4 and Ti thin films of high elastic modulus were deposited on GaAs and glass substrates of low elastic modulus, respectively. Experimental results showed that the thin films with different thickness were affected significantly by the substrate and the contact resonance frequency changes as a result of the varying thickness of the thin films. This research demonstrate that Ultrasonic-AFM may be a novel technique for the nondestructive measurement of nanoscale thin film thickness by considering substrate features.

Lukewarm and Trembling Therapy Device to Assist the Reduction of Blood Flow for Immobilized Patients

Reduction of blood flow due to immobility of legs de-escalates transportability of liberal number of patients in a extensive range of healing scheme transverse from bruise grume. In normal human being effective system of venous rejoin both alive and yielding is amenable for prohibition of profound venous apoplexy. Ultrasonic blood flow rate sensor, Tilt sensor, Force sensor and Accelerometer sensor are used to detect and identify the flow rate as well as ankle position. The paper offers prophylaxis and slimnastics device that caricature the essential proposition off venous recompense to uphold the blood flow gadget is based on Lukewarm and Trembling technique that is compress and appropriately from equipped in pattern and additionally requirement no restricted trainings for the operation.

Acoustic subsurface-atomic force microscopy: Three-dimensional imaging at the nanoscale

The development of acoustic subsurface atomic force microscopy, which promises three-dimensional imaging with single-digit nanometer resolution by the introduction of ultrasound actuations to a conventional atomic force microscope, has come a long way since its inception in the early 1990s. Recent advances provide a quantitative understanding of the different experimentally observed contrast mechanisms, which paves the way for future applications. In this Perspective, we first review the different subsurface atomic force microscope modalities: ultrasonic force microscopy, atomic force acoustic microscopy, heterodyne force microscopy, mode-synthesizing atomic force microscopy, and near-field picosecond ultrasonic microscopy. Then, we highlight and resolve a debate existing in the literature on the importance of the chosen ultrasound excitation frequencies with respect to the resonance frequencies of the cantilever and the observed contrast mechanisms. Finally, we discuss remaining open problems in the field and motivate the importance of new actuators, near-field picosecond ultrasonics, and integration with other techniques to achieve multi-functional non-destructive three-dimensional imaging at the nanoscale.

Scanning Probe Spectroscopy of WS2/Graphene Van Der Waals Heterostructures.

In this paper, we present a study of tungsten disulfide (WS2) two-dimensional (2D) crystals, grown on epitaxial Graphene. In particular, we have employed scanning electron microscopy (SEM) and µRaman spectroscopy combined with multifunctional scanning probe microscopy (SPM), operating in peak force–quantitative nano mechanical (PF-QNM), ultrasonic force microscopy (UFM) and electrostatic force microscopy (EFM) modes. This comparative approach provides a wealth of useful complementary information and allows one to cross-analyze on the nanoscale the morphological, mechanical, and electrostatic properties of the 2D heterostructures analyzed. Herein, we show that PF-QNM can accurately map surface properties, such as morphology and adhesion, and that UFM is exceptionally sensitive to a broader range of elastic properties, helping to uncover subsurface features located at the buried interfaces. All these data can be correlated with the local electrostatic properties obtained via EFM mapping of the surface potential, through the cantilever response at the first harmonic, and the dielectric permittivity, through the cantilever response at the second harmonic. In conclusion, we show that combining multi-parametric SPM with SEM and µRaman spectroscopy helps to identify single features of the WS2/Graphene/SiC heterostructures analyzed, demonstrating that this is a powerful tool-set for the investigation of 2D materials stacks, a building block for new advanced nano-devices.

Confocal air-coupled ultrasonic optical coherence elastography probe for quantitative biomechanics.

We present an air-coupled ultrasonic radiation force probe co-focused with a phase-sensitive optical coherence tomography (OCT) system for quantitative wave-based elastography. A custom-made 1 MHz spherically focused piezoelectric transducer with a concentric 10 mm wide circular opening allowed for confocal micro-excitation of waves and phase-sensitive OCT imaging. Phantom studies demonstrated the capabilities of this probe to produce quasi-harmonic excitation up to 4 kHz for generation of elastic waves. Experimental results in ocular tissues showed highly detailed 2D and 3D elasticity mapping using this approach with great potential for clinical translation.

An asteroid anchoring method based on cross-drilling geometric force closure of ultrasonic drill

Asteroid anchoring is the premise for the spacecraft to conduct in-situ scientific exploration on the surface of a weak gravitational asteroid. There is not any precedent for successful anchoring on the asteroid surface all over the world. Ultrasonic drill actuated by the piezoelectric ceramic is especially suitable for drilling on the surface of a weak gravitational asteroid, showing outstanding advantages such as low power consumption, low required drilling pressure and wide temperature range. In order to solve the technical problem of anchoring, a novel anchoring device based on multiple ultrasonic drill cross-drilling geometric force closure is proposed. Firstly, the structure and working principle of the anchoring device are introduced. Then the EDEM software based on the Discrete Element Method is used to simulate the influencing factors of the anchoring force. Finally, the effectiveness of the anchoring device is proved by experiments. The results show that the ultrasonic drill is effective for the anchoring device; the anchoring device can provide an anchoring force of 60–250 N for the spacecraft; its structure is simple, compact and adaptable.

Wire Bonding: The Ultrasonic Bonding Mechanism

Abstract Wire bonding is a welding process. During both ball and wedge bonding, wire and bond pad are massively deformed between the bond tool and the anvil of the bond pad or substrate. The dominant variables affecting deformation are ultrasonic energy, temperature, bond force and bond time. Deformation exposes new surface material that is clean and has not been exposed to atmospheric contamination and oxidation. As the new wire and bond pad surfaces mix, they form diffusion couples that grow and transform into the intermetallic weld nugget. The initial mixing is not at equilibrium in that it does not initially form the compounds described by the equilibrium phase diagram, but temperature and time very quickly allows diffusion to relax the initial mixture into the equilibrium phase diagram compounds. This paper will discuss the mechanisms behind the formation of ball and wedge bonds.

Morphological and Elastic Transition of Polystyrene Adsorbed Layers on Silicon Oxide.

Herein we present a study on the formation of irreversibly adsorbed layer of polystyrene molecules on silicon oxide surfaces. Various scanning probe microscopy techniques have been employed to study both the morphology and the mechanical properties of these self-assembled thin polymeric layers. More in detail, standard contact mode, force versus distance spectroscopy and ultrasonic force microscopy have been employed to obtain spatially-resolved maps and, thus, observe the physisorption of polystyrene on native silicon oxide substrate in function of time. Thick films, spin coated from a toluene solution, have been annealed at a temperature above the glass transition for increasing time intervals, and finally thoroughly rinsed in toluene. We have found that isolated islands of adsorbed chains are already present after an annealing time of half an hour. Prolonged annealing determines a progressive increase of the covered areas, whereas the formation of a complete flat layer requires 24 h. The pattern observed is in line with expected evolution of an unstable system, corresponding to the phenomenon of spinodal dewetting. Adhesion measurements show that the films present a reduced snap-off and the formation of a meniscus between tip and surface for annealing time up to 8 h. On the other hand, elastic measurements allow us to observe a progressive increase of the elastic modulus, with a complete transition for annealing time above 20 h. This is indication that a dense packing of the polystyrene molecules occurs, in line with the predictions of current models on the kinetics of irreversible adsorption. LAY DESCRIPTION: Herein we present a study on the formation of irreversibly adsorbed layer of polystyrene molecules on silicon oxide surfaces. Various scanning probe microscopy techniques have been employed to study both the morphology and the mechanical properties of these self-assembled thin polymeric layers. Thick polystyrene films, spin coated from a toluene solution, have been thermally annealed at a temperature above the glass transition for increasing time intervals, and finally thoroughly rinsed in toluene. We have found that isolated islands of adsorbed chains are already present after an annealing time of half an hour. Prolonged annealing determines a progressive increase of the covered areas, whereas the formation of a complete flat layer requires twenty-four hours. The adsorption pattern observed is in line with expected evolution of an unstable system, corresponding to the phenomenon of spinodal dewetting. Adhesion and elastic measurements have allowed us to observe a progressive increase of the packing density of the polystyrene molecules, in agreement with the predictions of current models on the kinetics of irreversible adsorption.

Reopening dentistry after COVID-19: Complete suppression of aerosolization in dental procedures by viscoelastic Medusa Gorgo.

The aerosol transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has impacted the delivery of health care and essentially stopped the provision of medical and dental therapies. Dentistry uses rotary, ultrasonic, and laser-based instruments that produce water-based aerosols in the daily, routine treatment of patients. Abundant aerosols are generated, which reach health care workers and other patients. Viruses, including SARS-CoV-2 virus and related coronavirus disease (COVID-19) pandemic, continued expansion throughout the USA and the world. The virus is spread by both droplet (visible drops) and aerosol (practically invisible drops) transmission. The generation of aerosols in dentistry-an unavoidable part of most dental treatments-creates a high-risk situation. The US Centers for Disease Control and The Occupational Safety and Health Administration consider dental procedures to be of "highest risk" in the potential spreading of SARS-CoV-2 and other respiratory viruses. There are several ways to reduce or eliminate the virus: (i) cease or postpone dentistry (public and personal health risk), (ii) screen patients immediately prior to dental treatment (by appropriate testing, if any), (iii) block/remove the virus containing aerosol by engineering controls together with stringent personal protective equipment use. The present work takes a novel, fourth approach. By altering the physical response of water to the rotary or ultrasonic forces that are used in dentistry, the generation of aerosol particles and the distance any aerosol may spread beyond the point of generation can be markedly suppressed or completely eliminated in comparison to water for both the ultrasonic scaler and dental handpiece.

Mapping nanoscale dynamic properties of suspended and supported multi-layer graphene membranes via contact resonance and ultrasonic scanning probe microscopies

Graphene’s (GR) remarkable mechanical and electrical properties—such as its Young’s modulus, low mass per unit area, natural atomic flatness and electrical conductance—would make it an ideal material for micro and nanoelectromechanical systems (MEMS and NEMS). However, the difficulty of attaching GR to supports, coupled with naturally occurring internal defects in a few layer GR can significantly adversely affect the performance of such devices. Here, we have used a combined contact resonance atomic force microscopy (CR-AFM) and ultrasonic force microscopy (UFM) approach to characterise and map with nanoscale spatial resolution GR membrane properties inaccessible to most conventional scanning probe characterisation techniques. Using a multi-layer GR plate (membrane) suspended over a round hole, we show that this combined approach allows access to the mechanical properties, internal structure and attachment geometry of the membrane providing information about both the supported and suspended regions of the system. We show that UFM allows the precise geometrical position of the supported membrane-substrate contact to be located and provides an indication of the local variation of its quality in the contact areas. At the same time, we show that by mapping the position sensitive frequency and phase response of CR-AFM response, one can reliably quantify the membrane stiffness, and image the defects in the suspended area of the membrane. The phase and amplitude of experimental CR-AFM measurements show excellent agreement with an analytical model accounting for the resonance of the combined CR-AFM probe-membrane system. The combination of UFM and CR-AFM provide a beneficial combination for the investigation of few-layer NEMS systems based on two dimensional materials.

Experimental studies on vapour compression refrigeration system using Al2O3/mineral oil nano-lubricant

ABSTRACT Nowadays, in many developing countries like India they are facing the shortage of energy. The Refrigeration system has become the major consumer of energy for many industrial as well as household applications. So, it is the need to enhance the energy efficiency of the refrigeration systems. Performance of the refrigeration system can be improved either by increasing the rate of heat absorption in evaporator or by reducing the compressor power. Use of efficient lubricant oil can help to remove the heat generated in the compression process which leads to less power consumption. Development in Nanotechnology makes it possible to develop a new class of lubricant called nanolubricant, in which nanoparticles are added in base lubricant oil to enhance the thermal properties. The two step technique with ultrasonic agitation force is used to synthesise stable nanolubricant.The present study investigates the performance of a R-134a refrigerant vapour compression refrigeration system using nanolubricant with different volume concentrations (0.05%, 0.075%, 0.1% and 0.2%) of Al2O3 to mineral oil (MO) experimentally. The result shows maximum enhancement in COP approximately as 85% for 0.075 % volume fraction Nano lubricant as compared to base fluid. Use of nanolubricant saves approximately 27% compressor power.