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1 – 10 of over 1000Lizhu Liu, Guangkai Hu, Xiaorui Zhang, Weng Ling and Jiawen Zhang
The effects of ultrasonication on the epoxy resin and its emulsion were investigated to find out the changes in the Mη and molecular structure of epoxy, as well as its room…
Abstract
Purpose
The effects of ultrasonication on the epoxy resin and its emulsion were investigated to find out the changes in the Mη and molecular structure of epoxy, as well as its room temperature storage stability, centrifugal stability, particle size and its distribution and particle morphology more importantly with the influence of different ultrasonic irradiation time, power and temperature.
Design/methodology/approach
The emulsion was prepared using an emulsifier with epoxy resin and by using phase inversion after subjecting to ultrasound irradiation with a power of 200 W at 50°C for 60 min. The changes in the epoxy resin and its emulsion induced by ultrasound were characterized by Ubbelohde viscometer, FT-IR, 13C-NMR, high-speed desktop centrifuge, laser particle size analyzer and transmission electron microscope.
Findings
The molecular weight of the epoxy resin was initially decreased and then stabilized by the increasing of ultrasonic irradiation time. The mole rate of the epoxy groups in epoxy molecular were decreased by about 14 per cent, resulting from ultrasonic irradiation. The particle size of the emulsion was decreased, while the particle size distribution became uniform in a certain time. The narrow distribution, stable and uniform of waterborne epoxy resin emulsion with more than 60 days room temperature storage period, 80 per cent of the supernatant volume, about 220 nm average particle size was gained with a power of 200 W at 50°C for 60 min.
Research limitations/implications
To overcome the problems commonly encountered with an epoxy emulsion, for example, short storage period and wider particle size, which limit its practical application, the effects of ultrasonic irradiation on the epoxy resin and its emulsion, were investigated. As the stability of emulsion was improved with the introduction of ultrasonic irradiation, the application of epoxy emulsion was improved.
Originality/value
The room temperature storage stability and centrifugal stability of the emulsion were decreased by the mechanical method, and thus, the benefit of an in-depth understanding of the influence of ultrasonic treatment on epoxy resin and its emulsion could further promote the development of water-based coatings.
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A. Fricker, R. Thompson and A. Manning
This paper aims to describe and evaluate the traditional methods for effective ink removal during the recycling of printed papers. Additionally, novel techniques for dealing with…
Abstract
Purpose
This paper aims to describe and evaluate the traditional methods for effective ink removal during the recycling of printed papers. Additionally, novel techniques for dealing with the newer “difficult to deink” inks such as toners from photocopiers, UV‐cured ink films and liquid toner suspensions or Electroinks® are to be evaluated.
Design/methodology/approach
High intensity ultrasound was applied to pulps derived from papers printed with these newer inks in order to evaluate its effectiveness in detaching the inks from paper and establishing the resultant ink particle size distributions.
Findings
When exposed to ultrasound at a frequency of 20 kHz, it was found that “difficult to deink” pulps did exhibit significant ink detachment. In the case of toners, temperature did have an effect on particle breakdown with larger numbers of particles produced at temperatures well below the softening point which was attributed to a greater brittleness of the toner at lower temperatures. Electroinks® can be effectively de‐inked by exposure to ultrasound coupled with washing under neutral conditions. With all the inks investigated, exposure to ultrasound resulted in the detached ink having particle size distributions that can be removed by conventional flotation and washing techniques.
Research limitations/implications
The exposure of the pulp to ultrasound was only carried out using a batch‐wise process. A future development would be to use a continuous flow system incorporating an annular ultrasound horn.
Practical implications
Introducing ultrasound exposure into a conventional deinking plant, all post‐consumer printed waste paper could be deinked without the use of deinking chemicals.
Originality/value
The findings are of interest to those in paper recycling.
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Andrew Manning, Anna Fricker and Robert Thompson
The purpose of this paper is to explore the previously unreported phenomenon in which changes occur to the particle size distributions of calcium carbonate fillers, used in…
Abstract
Purpose
The purpose of this paper is to explore the previously unreported phenomenon in which changes occur to the particle size distributions of calcium carbonate fillers, used in papermaking, when exposed to high intensity ultrasound.
Design/methodology/approach
Commercial paper pulps sonicated at a frequency of 20 kHz are found to produce aggregates of their mineral filler constituents. The effects of sonication on isolated long and short fibre, and ground and precipitated calcium carbonate filler systems are also investigated both with and without the presence of dispersants. The findings are supported by particle size analysis and scanning electron microscopy of the sonicated systems.
Findings
It is clearly shown that exposure to high intensity ultrasound induces filler aggregation. However, the effect only occurs when paper fibres and fillers coexist and is not apparent for suspensions of filler only or fibre only slurries. Furthermore, the treatment overrides the effect of dispersants used to keep filler in suspension during the manufacturing process. An accompanying fall in pH with increasing sonication times is also noted and is linked to these changes. It is proposed that radical species produced in the slurries during sonication may explain the observed phenomenon.
Research limitations/implications
The role of pH is not clearly understood and needs further study.
Practical implications
The findings may be of interest in paper manufacture where uniform dispersal of fillers throughout the pulp is of significant importance.
Originality/value
The phenomenon described in this paper has not previously been reported or explored. Further studies may add to knowledge of filler dispersions and their behaviour in papermaking.
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Knut E. Aasmundtveit, Trym Eggen, Tung Manh and Hoang-Vu Nguyen
This paper aims to demonstrate low-temperature bonding for piezoelectric materials at temperatures well below the relevant Curie temperatures so as to avoid depolarization of the…
Abstract
Purpose
This paper aims to demonstrate low-temperature bonding for piezoelectric materials at temperatures well below the relevant Curie temperatures so as to avoid depolarization of the piezoelectric material during bonding.
Design/methodology/approach
Au-coated test samples of lead zirconate titanate (PZT) are bonded to a WC-based resonant backing layer with In–Bi eutectic material in which the In–Bi metal system is a preform or thin, evaporated layers. The bonded samples are characterized using electrical impedance spectroscopy and cross-section microscopy. The first technique verifies the integrity of polarization and reveals the quality of the bondline in a non-destructive manner, particularly looking for voids and delaminations. The latter technique is destructive but gives more precise information and an overview of the structure.
Findings
Successful low-temperature (115°C) bonding with intact PZT polarization was demonstrated. The bondlines show a layered structure of Au/Au–In intermetallic compounds (with Bi inclusions)/Au, capable of withstanding temperatures as high as 271°C before remelting occurs. For bonded samples using In–Bi preform, repeatable bonds of high quality (very little voiding) were obtained, but the bonding time is long (1 h or more). For bonded samples using evaporated thin films of In–Bi, bonding can be performed in 30 min, but the process needs further optimization to be repeatable.
Originality/value
Low-temperature solid-liquid interdiffusion (SLID) bonding is a novel technique, merging the fields of low-temperature solder bonding with the SLID/transient liquid phase (TLP) approach, which is normally used for much higher temperatures.
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Domenico Carlucci, Luigi Roselli, Giacomo Giannoccaro, Carla Cavallo, Teresa Del Giudice, Riccardo Vecchio, Gianni Cicia and Bernardo Corrado De Gennaro
This study aims to investigate consumer acceptance for a set of innovations that can be applied to the production process of extra-virgin olive oil. The final purpose is to verify…
Abstract
Purpose
This study aims to investigate consumer acceptance for a set of innovations that can be applied to the production process of extra-virgin olive oil. The final purpose is to verify whether, and to what extent, consumer acceptance of innovations varies depending on the type of technology used and the profile of consumers.
Design/methodology/approach
A cross-sectional consumer survey has been carried out in Italy. A structured questionnaire was administered to a national representative sample of individuals who are responsible for grocery shopping (N = 1,003). Consumer acceptance for a set of ten innovations has been measured. Statistical differences between the various measures have been analysed through pairwise comparisons using Wilcoxon's signed-rank test, and subsequent effect sizes have been estimated. A cluster analysis has been also performed to distinguish consumer segments with different response patterns.
Findings
The results showed that the type of technology affects significantly the level of consumer acceptance of the tested innovations. In addition, high heterogeneity has been detected among consumer responses, and this leads to identify three consumer segments with different response patterns.
Originality/value
The study is focused on extra-virgin olive oil, which is one of the most important traditional food product in Mediterranean countries. This is the first study where several innovations for extra-virgin olive oil were jointly tested and compared for acceptance through a survey on a nation-wide representative sample of consumers.
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Mohammad Vaezi, Chee Kai Chua and Siaw Meng Chou
Today, medical models can be made by the use of medical imaging systems through modern image processing methods and rapid prototyping (RP) technology. In ultrasound imaging…
Abstract
Purpose
Today, medical models can be made by the use of medical imaging systems through modern image processing methods and rapid prototyping (RP) technology. In ultrasound imaging systems, as images are not layered and are of lower quality as compared to those of computerized tomography (CT) and magnetic resonance imaging (MRI), the process for making physical models requires a series of intermediate processes and it is a challenge to fabricate a model using ultrasound images due to the inherent limitations of the ultrasound imaging process. The purpose of this paper is to make high quality, physical models from medical ultrasound images by combining modern image processing methods and RP technology.
Design/methodology/approach
A novel and effective semi‐automatic method was developed to improve the quality of 2D image segmentation process. In this new method, a partial histogram of 2D images was used and ideal boundaries were obtained. A 3D model was achieved using the exact boundaries and then the 3D model was converted into the stereolithography (STL) format, suitable for RP fabrication. As a case study, the foetus was chosen for this application since ultrasonic imaging is commonly used for foetus imaging so as not to harm the baby. Finally, the 3D Printing (3DP) and PolyJet processes, two types of RP technique, were used to fabricate the 3D physical models.
Findings
The physical models made in this way proved to have sufficient quality and shortened the process time considerably.
Originality/value
It is still a challenge to fabricate an exact physical model using ultrasound images. Current commercial histogram‐based segmentation method is time‐consuming and results in a less than optimum 3D model quality. In this research work, a novel and effective semi‐automatic method was developed to select the threshold optimum value easily.
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N.P. Badgujar, Y.E. Bhoge, T.D. Deshpande, B.A. Bhanvase, P.R. Gogate, S.H. Sonawane and R.D. Kulkarni
– The present work aims to deal with ultrasound-assisted organic pigment (phthalocyanine blue and green) dispersion and its comparison with the conventional approach.
Abstract
Purpose
The present work aims to deal with ultrasound-assisted organic pigment (phthalocyanine blue and green) dispersion and its comparison with the conventional approach.
Design/methodology/approach
Ultrasound is expected to give beneficial results based on the strong shear forces generated by cavitational effects. The dispersion quality for preparation using an ultrasound-based method has been compared with dispersion obtained using high-speed dispersion mill. Effects of different operating parameters such as probe diameter and use of surfactants on the physical properties of dispersion and the colour strength have been investigated. Calculations for the energy requirement for two approaches have also been presented.
Findings
The use of sodium dodecyl sulphate and Tween 80 surfactants shows better performance in terms of the colour properties of dispersion prepared in water and organic solvent, respectively. Ultrasound gives better dispersion quality as compared to the conventional approach.
Originality/value
The present work presents a new approach of ultrasound-assisted dispersion of phthalocyanine blue and green pigments. Understanding into the effect of surfactants and type of solvent also presents new important design-related information.
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Pierre Vieyres, Gérard Poisson, Fabien Courrèges, Olivier Mérigeaux and Philippe Arbeille
Ultrasound examinations represent one of the major diagnostic modalities of future healthcare. They are currently used to support medical space research but require a high skilled…
Abstract
Ultrasound examinations represent one of the major diagnostic modalities of future healthcare. They are currently used to support medical space research but require a high skilled operator for both probe positioning on the patient's skin and image interpretation. TERESA is a tele‐echography project that proposes a solution to bring astronauts and remotely located patients on ground quality ultrasound examinations despite the lack of a specialist at the location of the wanted medical act.
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Andrew J. Cobley and Veronica Saez
Electroless plating is an important process in printed circuit board and electronics manufacturing but typically requires temperatures of 70‐95°C to give a suitable deposition…
Abstract
Purpose
Electroless plating is an important process in printed circuit board and electronics manufacturing but typically requires temperatures of 70‐95°C to give a suitable deposition rate. This is becoming problematic in industry due to the rising price of energy and is a major contribution to production costs. Previous studies have noted beneficial effects of ultrasonic irradiation upon electroless plating processes and it has been reported that sonication can increase the plating rate and produce changes to the chemical and physical properties of the deposited coating. The purpose of this paper is to reduce the operating temperature of an electroless nickel bath by introducing ultrasound to the process.
Design/methodology/approach
The deposition rate of an electroless nickel solution was determined by two techniques. In the first method, test coupons were plated in an electroless nickel solution at temperatures ranging from 50‐90°C and the plating rate was calculated by weight gain. In the second approach the mixed potential (and hence the current density at the mixed potential) was determined by electrochemical analysis of the anodic and cathodic reactions. In both cases the plating rate was found with and without the application of an ultrasonic field (20 kHz). The electroless nickel deposits obtained in the plating tests were also analysed to determine the phosphorus content, microhardness and brightness.
Findings
The plating rates under ultrasonic agitation were always higher than under “silent” conditions. Most importantly, considering the objectives of this study, the deposition rate under sonication at 70°C was significantly higher than that found with mechanical agitation at 90°C. In addition, the results indicated that the deposits produced in an ultrasonic field had consistently lower phosphorus content, higher microhardness and were brighter than those prepared in an electroless nickel bath that was not sonicated.
Originality/value
Although previous work has been performed on the effect of ultrasound on electroless plating, all these studies have been carried out at the normal operating temperature of the electroless process. In this paper, ultrasound has been applied at temperatures well below those normally used in electroless nickel deposition to determine whether sonication can enable low temperature electroless plating.
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Ultrasound is simply a name given to sound waves whose frequency (pitch) is too high to be detected by the human ear. The use of low‐intensity ultrasonic waves in level…
Abstract
Ultrasound is simply a name given to sound waves whose frequency (pitch) is too high to be detected by the human ear. The use of low‐intensity ultrasonic waves in level measurement, flow detection, and medical imaging is well known. Here, a pulse of ultrasound is used to ‘probe’ the sample under investigation; comparison of the pulse shape before and after transmission, and a measurement of the transit time in the sample can provide information on many physical parameters. For these applications, the intensity of the ultrasonic burst is not sufficient to affect the material, and no chemical or physical changes are involved.