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The purpose of this paper is to identify if the implementation of ultrasonic vibration in laser engineered net shaping (LENS) process can help to reduce internal weaknesses such as porosity, coarse primary TiB whisker and heterogeneous distribution of TiB reinforcement in the LENS-fabricated TiB reinforced Ti matrix composites (TiB-TMC) parts.

An experimental investigation is performed to achieve the results for comparative studies under different fabrication conditions through quantitative data analysis. An approach of microstructural characterization and mechanical testing is conducted to obtain the output attributes. In addition, the theoretical analysis of the physics of ultrasonic vibration in the melting materials is presented to explain the influences of ultrasonic vibration on the microstructural evolution occurred in the part fabrication.

Because of the nonlinear effects of acoustic streaming and cavitation induced by ultrasonic vibration, porosity is significantly reduced and a relatively small variation of pore sizes is achieved. Ultrasonic vibration also causes the formation of smaller TiB whiskers that distribute along grain boundaries with a homogeneous dispersion. Additionally, a quasi-continuous network (QCN) microstructure is considerably finer than that produced by LENS process without ultrasonic vibration. The refinements of both reinforcing TiB whiskers and QCN microstructural grains further improve the microhardness of TiB-TMC parts.

The novel ultrasonic vibration-assisted (UV-A) LENS process of TiB-TMC is conducted in this work for the first time to improve the process performance and part quality.

The purpose of this paper is to investigate the factors effecting ultrasonic seam tensile properties.

In this study, 100 percent polypropylene and 100 percent polyester spunbond and meltblown nonwoven fabrics were sewn by using ultrasonic sewing machine with different rollers which have two, three and four rows. Seam tensile properties of the sewn nonwoven fabrics were investigated. Four-Level Nested Anova Design was applied to the data by using Minitab 15 software program.

Higher seam strength values were obtained by using four rows roller, PP fiber, spunbond fabric and 50 g/m2 fabric area density for all nonwoven fabrics. Statistical significance was found between fabric area density, roller rows and seam tensile strength properties and between fabric type, roller rows and seam elongation at break values.

When the authors look at the studies related to ultrasonic sewing, several researchers studied on welding parameters of ultrasonic sewing but very limited studies were performed on assembling of nonwoven fabrics with ultrasonic sewing. Therefore effect of production methods of nonwoven fabrics on the properties of ultrasonic sewing such as seam strength and elongation at break should be investigated.

Surgical gowns should be designed and produced using special techniques to provide barrier properties against potential risks during surgery and healthcare procedures. Ultrasonic welding is one of these methods used to produce surgical gowns with determined barrier properties. The purpose of this paper is to analyse bond strength and permeability properties of ultrasonically welded nonwoven fabrics and compare them with traditional sewing techniques.

In this study, ultrasonic welding of nonwovens was performed to demonstrate its use as an assembly method. Performance requirements in the design of surgical gowns were determined. Fabric strengths and bond strengths of ultrasonic-welded and traditionally sewn fabrics were analysed. The performance properties, i.e., bond strength, air and water resistance of the fabrics and the joints obtained by ultrasonic and classical sewing methods were studied.

As a result, it was found that ultrasonic welding technique is a suitable method for joining layers in surgical gown production bringing the advantages of high water resistance together with acceptable bond strength.

The current study focuses on the use of ultrasonic welding of nonwovens used for disposable protective surgical gowns. Ultrasound welding technique was presented as an alternative to classic assembly methods and ultrasonic welding technology was applied to different fabric combinations simulating different layers in different joining sections of a surgical gown.

A simple interaction‐potential model has been established to calculate the higher order elastic constants of intermetallic YbAl2 in the temperature range from 10‐300K. Temperature dependent second and third order elastic constants are used for the determination of the ultrasonic attenuation, velocity, Grüneisen numbers, Acoustic‐coupling constants, and thermal relaxation time at the different temperatures. Temperature dependency of the ultrasonic properties of YbAl2 is similar at low temperatures to that of pure metals and the low carrier heavy fermion systems ‐ LaSb, YbAs and YbP having simple NaCl‐type structures. Thermal energy density makes significant contribution to the total attenuation in the compound at the higher temperatures from 100‐300K. Effect of the magnetic field on the ultrasonic attenuation is also evaluated using the magneto resistance data. At 100K, the effect of the magnetic field becomes insignificant. The attenuation decreases with the field at 3K to 50K.

The purpose of this paper is to present the results of acoustic emission (AE) and ultrasonic inspection of two H₂S storage tanks carried out in a heavy water plant, in order to characterize point type defects observed during earlier ultrasonic inspection and to ensure that these defects are not growing during hydrotesting of the tanks.

Using multiple AE sensors and AE source location methodology, the entire tank could be covered to detect and locate any dynamic sources of AE associated with local plastic deformation and/or growing discontinuities from any part of the tank during the hydrotest. For confirmation of the results obtained by AE, ultrasonic inspection on the tanks and on virgin plates from which the tanks were manufactured, were carried out.

The AE signals generated during first pressurisation are attributed to the micro yielding of the material of the tanks. A few scattered AE events were observed at a few locations during the hydrotesting of the tanks and these are due to structural and rubbing noise. During hold periods and repressurising cycle of the hydrotesting, no detectable AE events were observed and this confirmed the absence of any growing discontinuity in the tanks during the hydrotesting. Ultrasonic inspection on the tanks and on virgin plates confirmed that the point type defects detected are manufacturing defects and not formed during service life.

The combined results from AE and ultrasonic techniques confirmed the structural integrity of the tanks and ensured their healthiness for continued operation.

The paper brings out the use of AE and ultrasonic techniques for monitoring hydrotesting of storage tanks of a heavy water plant. The storage tanks where point type defect indications were reported during previous ultrasonic inspection and whether these defects are growing during hydrotesting of the tanks or not, were required to be known before the tanks are put in to further service. AE signals collected during pressurising and repressurising cycles of the hydrotest and subsequent inspection by ultrasonic confirmed the vessels to be free from growing defects during the hydrotest and provided baseline data for future inspection.

The aim of the paper is to study the feasibility of direct ultrasonic bonding between contact pad arrays on flexible printed circuit boards (FPCB) and rigid printed circuit boards (RPCB) at ambient temperature.

Metallization layers on the RPCB comprised Sn on Cu while the pads on the FPCB consisted of Au/Ni/Cu. Prepared RPCB and FPCB were bonded by ultrasound at ambient temperature using an ultrasonic frequency of 20 kHz, a power of 1,400 W, and 0.62 MPa of bonding pressure. The bonded samples were cross‐sectioned and the joints and microstructures were observed by Field Emission Scanning Electron Microscopy (FE‐SEM) and Energy Dispersive Spectroscopy (EDS). The soundness of the joints was evaluated by pull testing.

Robust bonding between FPCB and RPCB was obtained by bonding for 1.0 and 1.5 s. This result has confirmed that direct room temperature ultrasonic bonding of Au and Sn is feasible. At a longer bonding time of 3.0 s, cracks and voids were found in the joints due to excessive ultrasonic energy. The IMC (intermetallic compound) between the Sn layer and pads of the RPCB was confirmed as Cu₆Sn₅. On the FPCB side, Cu₆Sn₅ and Ni₃Sn₄ were formed by contact with the facing Sn coating, and mechanically alloyed Cu_0.81Ni_0.19 was found within the pads. Meanwhile, the strength of bonded joints between FPCB and RPCB increased with bonding time up to 1.5 s and the maximum value reached 12.48 N. At 3.0 s bonding time, the strength decreased drastically, and showed 5.75 N. Footprints from the fracture surfaces showed that bonding started from the edges of the metal pads, and extended to the pad centers as ultrasonic bonding time was increased.

Direct ultrasonic bonding with transverse vibration at ambient temperature between the surface layers of the pads of FPCB and RPCB has been confirmed to be feasible.

This study aims to investigate the effect of ultrasound on interfacial microstructures and growth kinetics of intermetallic compounds (IMCs) at different temperatures.

To investigate the effect of ultrasound on IMCs growth quantitatively, the cross-sectional area of IMCs layers over a confirmed length was obtained for calculating the thickness of the IMCs layer.

The generation of dimensional difference in normal direction between Cu₆Sn₅ and its adjacent Cu₆Sn₅, formation of bossed Cu₆Sn₅ and non-interfacial Cu₆Sn₅ in ultrasonic solder joints made the interfacial Cu₆Sn₅ layer present a non-scallop-like morphology different from that of traditional solder joints. At 260°C and 290°C, the Cu₃Sn layer presented a wave-like shape. In contrast, at 320°C, the Cu₃Sn in ultrasonic solder joints consisted of non-interfacial Cu₃Sn and interfacial Cu₃Sn with a branch-like shape. The Cu₆Sn₅/Cu₃Sn boundary and Cu₃Sn/Cu interface presented a sawtooth-like shape under the effect of ultrasound. The predominant mechanism of ultrasonic-assisted growth of Cu₆Sn₅ growth at 260°C, 290°C and 320°C involved the grain boundary diffusion accompanied by grain coarsening. The Cu₃Sn growth was controlled by volume diffusion during the ultrasonic soldering process at 260°C and 290°C. The diffusion mechanism of Cu₃Sn growth transformed to grain boundary diffusion accompanied by grain coarsening when the ultrasonic soldering temperature was increased to 320°C.

The microstructural evolution and growth kinetics of IMCs in ultrasonically prepared ultrasonic solder joints at different temperatures have rarely been reported in previous studies. In this study, the effect of ultrasound on microstructural evolution and growth kinetics of IMCs was systematically investigated.

Purpose – The purpose of this research is to design and build a wild animal pest repellent device with combination of passive infrared (PIR) sensor and ultrasonic signal based on microcontroller as system controller. The PIR sensor is used to detect the presence of wild animal objects and ultrasonic signals to interfere with the hearing.

Design/Methodology/Approach – The design of the system is built based on microcontroller as the system controller. The system as a whole includes hardware and software. The design of hardware consists of the system design on the transmitter side and the system design on the receiver side, while the software in the of system are algorithms using C language programming.

Findings – The resulting repellent device can detect animals approaching up to a distance of 5 m and may interfere with its hearing with a 40 kHz ultrasonic frequency up to a distance of 20 m. The system also uses remote monitoring devices using 433 MHz radio frequency up to a distance of 60 m.

Research Limitations/Implications – Each animal has different hearing frequencies, as well as some wild animals, but the hearing frequencies of wild animals are generally at ultrasonic frequencies. The frequency of animal hearing may vary from audio frequency to ultrasonic frequency, so ultrasonic wave emission testing with varying frequencies is required.

Practical Implications – This research combines systems on transmitters and receivers, with real-time monitoring of wild animal positions, and it can be possible to monitor the position of more detailed animals by installing more types of sensors as well as increasing the number of sensors.

Originality/Value – This paper may provide additional insight into the hearing frequencies of animals and may also serve as comparable papers for similar studies.

The effects of ultrasonic agitation on electronic components during PCB cleaning has long been the subject of controversy. This paper summarises the results of a series of studies into these effects for a range of components using CFC, aqueous and semi‐aqueous cleaning media. The variations with exposure time and power density under various ultrasonic stress conditions (loose, mounted on PCBs, or on purpose‐built test boards) are discussed. The results are encouraging and suggest that there is a large margin of safety when employing currently accepted regimes of operation and good quality components. However, the strong dependence of the damage accumulation on power density emphasises the need to specify and tightly control the power density used.

Analyses the effects of temperature on the behaviour of ultrasonic sensors applied to object recognition. Describes the measurement system employed, the environmental considerations of ultrasonic sensors and looks at the most commonly used parameters to analyse the echo form in the recognition process. Evaluates the performance of the parametric model of the ultrasonic echo signal with a comparative study of different ultrasonic transducers.