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| 2. |
- Bhat, Soha Maqbool, et al.
(author)
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Design of Cost-Efficient SRAM Cell in Quantum Dot Cellular Automata Technology
- 2023
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In: Electronics. - : MDPI. - 2079-9292. ; 12:2
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Journal article (peer-reviewed)abstract
- SRAM or Static Random-Access Memory is the most vital memory technology. SRAM is fast and robust but faces design challenges in nanoscale CMOS such as high leakage, power consumption, and reliability. Quantum-dot Cellular Automata (QCA) is the alternative technology that can be used to address the challenges of conventional SRAM. In this paper, a cost-efficient single layer SRAM cell has been proposed in QCA. The design has 39 cells with a latency of 1.5 clock cycles and achieves an overall improvement in cell count, area, latency, and QCA cost compared to the reported designs. It can therefore be used to design nanoscale memory structures of higher order.
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| 4. |
- Chen, Liu, et al.
(author)
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High Gradient Magnetic Separation of Pure Gd2O3 Particles from Pure La2O3 Particles
- 2023
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In: Metals. - : MDPI. - 2075-4701. ; 13:2
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Journal article (peer-reviewed)abstract
- Rare earth oxides such as La2O3 and Gd2O3 are abundant in waste optical glass. The separation of rare earth oxides is beneficial to the recycling of rare earth resources. In this study, the rare earth oxide Gd2O3 particles were separated from La2O3 particles using high gradient magnetic separation, and the influence of different fluid media (i.e., water, anhydrous ethanol, and their mixture) on the separation results was investigated. By using the measured zeta potential of oxide particles in water/ethanol of different pH and water with different dispersants (Na2SiO3 9H2O, citric acid, Na2CO3, and sodium hexametaphosphate), the DLVO (Derjaguin–Landau–Verwey–Overbeek) potential calculations and their analysis applied to high gradient magnetic separation results were also performed. The results showed that using anhydrous ethanol or adding a dispersant in water as a fluid medium can promote the separation of magnetic Gd2O3 particles under a high-gradient magnetic field. Among the different conditions, anhydrous ethanol can improve the grade of Gd2O3 to 95% from 70% with water. Furthermore, ethanol can be reused after filtration, making it an environmentally friendly fluid medium. Among the four dispersants, sodium hexametaphosphate, Na2SiO3, and Na2CO3 can also increase the separation rate of La2O3 and Gd2O3 to about 95%. The effect of citric acid on the separation performance is slightly worse, and the recovery rate of Gd2O3 is 80%. This study provides a new reference for selecting a fluid medium for magnetic separation.
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| 5. |
- Elphick, Kelvin, et al.
(author)
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Non-Destructive Imaging on Synthesised Nanoparticles
- 2021
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In: Materials. - : MDPI. - 1996-1944. ; 14:3
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Journal article (peer-reviewed)abstract
- Our recently developed non-destructive imaging technique was applied for the characterisation of nanoparticles synthesised by X-ray radiolysis and the sol-gel method. The interfacial conditions between the nanoparticles and the substrates were observed by subtracting images taken by scanning electron microscopy at controlled electron acceleration voltages to allow backscattered electrons to be generated predominantly below and above the interfaces. The interfacial adhesion was found to be dependent on the solution pH used for the particle synthesis or particle suspension preparation, proving the change in the particle formation/deposition processes with pH as anticipated and agreed with the prediction based on the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. We found that our imaging technique was useful for the characterisation of interfaces hidden by nanoparticles to reveal the formation/deposition mechanism and can be extended to the other types of interfaces.
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| 6. |
- Fukushima, Kyosuke, et al.
(author)
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Equivalent Circuit Models: An Effective Tool to Simulate Electric/Dielectric Properties of Ores—An Example Using Granite
- 2022
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In: Materials. - : MDPI. - 1996-1944. ; 15:13
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Journal article (peer-reviewed)abstract
- The equivalent circuit model is widely used in high-voltage (HV) engineering to simulate the behavior of HV applications for insulation/dielectric materials. In this study, equivalent circuit models were prepared in order to represent the electric and dielectric properties of minerals and voids in a granite rock sample. The HV electric-pulse application shows a good possibility of achieving a high energy efficiency with the size reduction and selective liberation of minerals from rocks. The electric and dielectric properties were first measured, and the mineral compositions were also determined by using a micro-X-ray fluorescence spectrometer. Ten patterns of equivalent circuit models were then prepared after considering the mineral distribution in granite. Hard rocks, as well as minerals, are dielectric materials that can be represented as resistors and capacitors in parallel connections. The values of the electric circuit parameters were determined from the known electric and dielectric parameters of the minerals in granite. The average calculated data of the electric properties of granite agreed with the measured data. The conductivity values were 53.5 pS/m (measurement) and 36.2 pS/m (simulation) in this work. Although there were some differences between the measured and calculated data of dielectric loss (tanδ), their trend as a function of frequency agreed. Even though our study specifically dealt with granite, the developed equivalent circuit model can be applied to any other rock.
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| 7. |
- Fukushima, Kyosuke, et al.
(author)
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Simulation of Electrical and Thermal Properties of Granite under the Application of Electrical Pulses Using Equivalent Circuit Models
- 2022
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In: Materials. - : MDPI. - 1996-1944. ; 15:3
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Journal article (peer-reviewed)abstract
- Since energy efficiency in comminution of ores is as small as 1% using a mechanical crushing process, it is highly demanded to improve its efficiency. Using electrical impulses to selectively liberate valuable minerals from ores can be a solution of this problem. In this work, we developed a simulation method using equivalent circuits of granite to better understand the crushing process with high-voltage (HV) electrical pulses. From our simulation works, we calculated the electric field distributions in granite when an electrical pulse was applied. We also calculated other associated electrical phenomena such as produced heat and temperature changes from the simulation results. A decrease in the electric field was observed in the plagioclase with high electrical conductivity and void space. This suggests that the void volume in each mineral is important in calculating the electrical properties. Our equivalent circuit models considering both the electrical conductivity and dielectric constant of a granite can more accurately represent the electrical properties of granite under HV electric pulse application. These results will help us better understand the liberation of minerals from granite by electric pulse application.
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| 8. |
- Gonçalves, Pedro Pereira, et al.
(author)
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Determination of Liberation Degree of Mechanically Processed Waste Printed Circuit Boards by Using the Digital Microscope and SEM-EDS Analysis
- 2019
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In: Electronics. - : MDPI. - 2079-9292. ; 8:10
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Journal article (peer-reviewed)abstract
- Characterization of heterogeneous materials, such as particles from mechanically processed waste printed circuit boards, is a challenging task. The majority of characterization methods either give average information or information that is very limited and in a tiny area of specific interest. That said, capturing such heterogeneity is significantly important for any kind of processes. Degree of liberation, indicating how much the target component is liberated from the non-valuable components, is a key property to determine the success of subsequent process for valuable material recovery. This work analyzed the degree of liberation of metals within the products of hammer milling process via the combination of image acquisition and analysis. The digital microscope and a scanning electron microscope (SEM) coupled with the energy dispersive spectroscopy (EDS) were used for image acquisition and elemental mapping, in order to evaluate the selective liberation under different milling conditions (i.e., feed mass, milling time) for different metals (mainly Cu and Al) and particle size fractions. The obtained liberation degree was also modelled and determined the liberation parameters that were compared. The results showed that the degree of liberation significantly depend on the milling conditions and metals we analyzed, and well correlated with the selective metal enrichment behavior. Results between the two methods showed some similarities and discrepancies. The advantages and disadvantages of the above two methods were identified and discussed in the paper, in addition to their methodological developments.
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| 9. |
- Han, Zhenyao, et al.
(author)
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Arsenic (III) oxidation and removal from artificial mine wastewater by blowing O2 nanobubbles
- 2022
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In: Journal of Water Process Engineering. - : Elsevier. - 2214-7144. ; 47
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Journal article (peer-reviewed)abstract
- This study found that with the help of O2 nanobubble pre-oxidation treatment effective arsenic removal was successfully achieved and is expected to be applicable on an industrial scale. The main research findings to remove arsenic are as follows. The oxidation of As(III) by blowing out O2 nanobubbles, O2 millimeter-sized bubbles, and air nanobubbles was studied under the condition of As(V) equilibrium at pH 1of the Pourbaix diagram. At pH 1, only O2 nanobubbles were able to oxidize As(III) to As(V). At the same time, the oxidation rate of As(III) was about 20% in the presence of air nanobubbles and 0% in the presence of O2 millimeter-sized bubbles. According to the extended DLVO theory, O2 nanobubbles are unstable at acidic pH. Nanobubbles grow and break, and then OH is produced. Below pH 3, H3AsO3 reacts with OH and converts to H3AsO4 while As(III) is oxidized to As(V). Ferric hydroxide co-precipitation with arsenic was effective to remove arsenic ions at more than 20Fe/As mass ratio and pH higher than 4. The As(V) removal rate was higher than As(III) at acidic pH because anionic HAsO42− ion could be adsorbed onto positively charged ferric hydroxide. In the artificial mine wastewater treatment, the sedimentation height of coprecipitated sludge was reduced by O2 nanobubble utilization due to O2 and Fe(OH)3 hetero-coagulation.
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| 10. |
- Han, Zhenyao, et al.
(author)
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Nanobubble size distribution measurement by interactive force apparatus under an electric field
- 2023
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Journal article (peer-reviewed)abstract
- Nanobubbles have been applied in many fields, such as environmental cleaning, material production, agriculture, and medicine. However, the measured nanobubble sizes differed among the measurement methods, such as dynamic light scattering, particle trajectory, and resonance mass methods. Additionally, the measurement methods were limited with respect to the bubble concentration, refractive index of liquid, and liquid color. Here, a novel interactive force measurement method for bulk nanobubble size measurement was developed by measuring the force between two electrodes filled with bulk nanobubble-containing liquid under an electric field when the electrode distance was changed in the nm scale with piezoelectric equipment. The nanobubble size was measured with a bubble gas diameter and also an effective water thin film layer covered with a gas bubble that was estimated to be approximately 10 nm based on the difference between the median diameter of the particle trajectory method and this method. This method could also be applied to the solid particle size distribution measurement in a solution.
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