Nanomaterials and nanotechnology are emerging as promising strategies for medical devices due to their advantageous properties, including the ability to effectively interact with biomolecules and tissues, as well as enhance therapeutic efficacy and biocompatibility. This has resulted in approved and candidate devices in fields, such as orthopedics, dentistry, wound care, and neurology. However, the overall progress in translating medical devices using nanomaterials has been relatively slow, highlighting the urgent need to advance regulatory science. Regulatory authorities and organizations, such as the National Medical Products Administration in China and the European Union, have issued essential guidance documents for these devices' safety and efficiency evaluation. These documents include special requirements and considerations for physicochemical characterization, biological evaluation, and other aspects. Although some evaluation paths have been defined, ongoing advancements in technologies and methods are expected to enhance safety evaluation practices, reduce burdens on the medical device industry, and accelerate the clinical translation of medical devices using nanomaterials. Herein, we review the current state of regulatory science related to medical devices using nanomaterials, suggest the feasibility of using in vitro alternative methods to advance regulatory science, and offer forward-looking insights to inspire new ideas and technologies for accelerating clinical translation.

With the increased aging population and economic climate, people's demand for healthcare has changed from seeking medical treatment after illness to maintaining active health into later years. Flexible electronic technological advancements have now given us the potential to develop wearable, next-generation implantable medical devices. However, before flexible electronic technology is expected to be commonplace for medical devices, safety and effectiveness in their intended clinical uses must first be proven. This paper summarizes the latest developments in flexible electronic technology in the context of medicine and healthcare, with emphasis on the requirements for safety and effectiveness evaluation of such innovations for medical devices from the perspective of regulatory science. Herein, we attempt to establish a standardized evaluation system suitable for the characteristics of flexible electronic technology, with the goal to help expedite the development of innovative medical devices based on flexible electronic technology from the laboratory to clinically approved products. (C) 2020 Elsevier Ltd. All rights reserved.

We designed and succeeded in synthesising a sequence of g-C3N4/Zn3In2S6 (ZIS) composite photocatalysts by means of one-step hydrothermal synthesis, which integrated different amounts of g-C3N4 into ZIS. The prepared products are characterized by means of various characterization methods to determine their structure, morphology and physicochemical properties. Their photocatalytic activities were assessed according to the performance of tetracycline (C22H24N2O8, TC) degradation experiments with light radiation. This consequence of experiments showing that the g-C3N4 (0.5 wt.%)/ZIS photocatalyst is most effective for the photodegradation of TC. Moreover, results from the cyclic tests confirm the stability of the g-C3N4 (0.5 wt.%)/ZIS composite, which remained active after five cycles of repeated photocatalysis experiments. We can get the conclusion that center dot O-2(-), center dot OH and h(+) all played roles during the degradation process from the figures of ESR tests and active species trapping experiments. And the corresponding degradation mechanism of g-C3N4/ZIS composites is proposed. High specific surface areas, desirable absorption capability, suppression of charge recombination should be put down to its nice photocatalytic performance. Thus, it can be considered that g-C3N4/ZIS composites have broad potential application prospects in photocatalysis degradation.

To improve the adsorption capacity, reduce the disposal cost, and enhance the separation efficiency of common activated carbon as an adsorbent in wastewater treatment, a novel thiol-modified magnetic activated carbon adsorbent of NiFe2O4-PAC-SH was successfully synthesized with a facile and safe hydrothermal method without any toxic and harmful reaction media. The as-prepared NiFe2O4-PAC-SH can effectively remove mercury(II) ions from aqueous solution. The maximal adsorption capacities from the experiment and Langmuir fitting achieve 298.8 and 366.3 mg/g at pH 7, respectively, exceeding most of adsorptive materials. The as-prepared NiFe2O4-PAC-SH has an outstanding regeneration performance, remarkable hydrothermal stability, and efficient separation efficiency. The data of kinetics, isotherms, and thermodynamics show that the adsorption of mercury(II) ions is spontaneous and exothermic. Ion exchange and electrostatic attraction are the main adsorption factors. The experimental results exhibit that the NiFe2O4-PAC-SH can be a prominent substitute for conventional activated carbon as an adsorbent.

After decades of evolution and improvements, Artificial Intelligence (AI) is now taking root in our daily lives, and is starting to profoundly influence the fields of architecture and sustainability. The applications of AI to sustainable architecture include energy-efficient building design, forecasting and minimizing energy consumption, strategizing for mitigating impacts on environment and climate, and enhancements in the safety and comfort of the living environment. Due to the significant increases in internet speed and accessibility and the drops in computer prices and data storage costs in recent years, Big Data (BD) nowadays plays an important supplementary role to AI. Algorithms and computer codes have been developed for data mining and analysis. BD rejuvenates AI methods and applications in many areas, including sustainable architecture. The present paper starts with an introduction to AI history and techniques. This is followed by a discussion on how AI and BD can be used to design and operate energy-efficient commercial buildings and residential houses, followed by a review of recent applications of AI and BD to energy-efficient buildings with an emphasis on the use of machine learning (ML) and large databases. Future research topics are suggested at the end of this paper. It is reemphasized in the present paper that AI, when combined with BD, can tremendously increase the energy efficiency and cost effectiveness of buildings which are designed to provide occupants with a comfortable indoor living environment. (c) 2019 Elsevier B.V. All rights reserved.

To heighten the absorption to visible light and improve photocatalytic degradation to organic pollutants, a novel photocatalyst of m-Bi2O4/Bi2O2CO3 was constructed through a facile hydrothermal method. The crystal structure, optical properties, morphology, composition and photocatalytic ability of the photocatalysts were characterized via X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscope (TEM), high resolution TEM, selected-area electron diffraction and X-ray photoelectron spectroscopy technologies. The as-prepared photocatalysts could efficiently degrade rhodamine B and mixed dye under visible light. The removal rate was up to 95.3% within 50 min. The results demonstrated that m-Bi2O4/Bi2O2CO3 photocatalysts showed outstanding photocatalytic degradation ability compared to the single photocatalyst with the narrow band gap. In addition, photocurrent response tests certified that the heterostructure of the photocatalysts effectively accelerated the separation and migration of photo-induced electrons and holes. Active species trapping experiments indicated that holes (h+) and superoxide radical (•O2−) were major species rather than hydroxyl radicals (•OH) during the degradation process of organics. According to the test results, a probable photocatalytic mechanism was proposed. This work provided a new and efficient photocatalyst for environmental remediation and water treatment.

A novel flower-like Bi2O4/ZnO heterojunction photocatalyst was synthesized through a facile two-step hydrothermal method and characterized by different technologies. The characterization results indicated that the photoluminescence spectrum of pure ZnO was greatly reduced by the formation of heterojunction at the interface of ZnO and Bi2O4 and the photocurrent intensity of the catalyst was 6.4 µA, which was 4.9 times higher than that of pure ZnO, resulting in an efficient separation of electron–hole pairs. The experimental results displayed that the as-prepared heterojunction of (1:3) Bi2O4/ZnO effectively prevented the agglomeration of nano-ZnO in aqueous solution and had a great high photocatalytic activity on degrading methylene blue and tetracycline under visible light. The photodegradation rates of (1:3) Bi2O4/ZnO for methylene blue and tetracycline were approximately 380 and 309.5 times higher than those of pure ZnO, respectively, and 95.68% of methylene blue and 85.68% of tetracycline were degraded under visible light within half an hour. The mineralization results showed that the two pollutants were firstly decomposed into intermediate products and then further fully mineralized. The results also indicated that the catalyst of (1:3) Bi2O4/ZnO had good stabilization and high reusability. Moreover, reactive species of ·O2− and h+ were proved to play a dominant role on accelerating the process of degradation. In the end, the detailed mechanism of photocatalytic degradation was proposed.

The photocatalytic ability of ZnO is improved through the addition of flower-like Bi2WO6 to prepare a Bi2WO6/ZnO composite with visible light activity. The composite is characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy with UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption-desorption isotherms. After modification, the band gap energy of Bi2WO6/ZnO is reduced from 3.2 eV for ZnO to 2.6 eV. Under visible light irradiation, the Bi2WO6/ZnO composite shows an excellent photocatalytic activity for degrading methylene blue (MB) and tetracycline. The photo-degradation efficiencies of (0.3:1) Bi2WO6/ZnO for MB and tetracycline are approximately 246 and 4500 times higher than those of bare ZnO, respectively, and correspondingly, the photo-degradation rates for the two pollutants are approximately 120 and 200 times higher than those with bare ZnO, respectively. Moreover, the photocatalyst of (0.3:1) Bi2WO6/ZnO exhibits a higher transient photocurrent density of approximately 4.5 μA compared with those of bare Bi2WO6 and ZnO nanoparticles. The successful recombination of Bi2WO6 and ZnO enhances the photocatalytic activity and reduces the band gap energy of ZnO, which can be attributed to the effective separation of electron–hole pairs. Active species trapping experiments display that [O2]− is the major species involved during photocatalysis rather than •OH and h+. This study provides insight into designing a meaningful visible-light-driven photocatalyst for environmental remediation.

A combined thermal and flow analysis was carried out to study the behavior and performance of a simple, commercial LTD (low-temperature-differential) heat engine. Laminar-flow solutions for annulus and channel flows were employed to estimate the viscous drags on the piston and the displacer, and the pressure difference across the displacer. Temperature correction factors were introduced in the thermal analysis to account for the departures from the ideal heat transfer processes. The flow analysis results indicate that the work required to overcome the viscous drags on engine moving parts is very small for engine speeds below 10 RPS (revolutions per second). The work required to move the displacer due to the pressure difference across the displacer is also one-to-two orders of magnitude smaller than the moving-boundary work of the piston for temperature differentials in the neighborhood of 20 °C and engine speeds below 10 RPS. A comparison with experimental data reveals large degradations from the ideal heat transfer processes inside the engine.

A simple and environmentally friendly material, CoFe2O4@SiO2–SH, was prepared successfully with CoFe2O4 nanoparticles coated by SiO2 which was further functionalized with thiol groups (–SH).

Integration of multiple sound generators is essential to the development of large-scale, sono-assisted processes such as combustion, evaporation, or CO2 capture with acoustic excitations. In this work, the transient and synchronized behaviors of a thermal acoustic converter (TAC) pair were investigated experimentally for various crossing angles and different separation distances between the converters. The two TACs were acoustically coupled through the air mass between their openings, and the only mode-locking operation that could be achieved was the one that was nearly 180 degrees out of phase. The time to achieve synchronization was found to be dependent upon the initial mistuning of the frequencies and the crossing angle between the converter axes. The synchronization process could also be accelerated by turning on the converter with the lower power input first. When the separation distance between the two converters exceeded a certain value, synchronization of the TAC pair could not be achieved. As the separation distance increased, the maximum amplitude of the unsynchronized TAC pair became less and less than the sum of the maximum amplitudes of the two converters when operating individually.

A thermal-to-acoustic energy converter (TAC) was developed and tested to produce sound waves in the kilohertz range directly from solar energy. The converter consisted of a glass window and a small amount of steel wool in the shape of a disk sealed in an aluminum housing. A Fresnel lens and a chopper wheel with 60 holes in it were employed to generate a pulsed sunbeam of approximately 200 sun intensity as the heat source of the TAC. Various designs and techniques were tested to improve the sound amplitude and signal-to-noise ratio of the converter at high frequencies. Reduction in air volume, better cooling, and improvement in air tightness were found to be effective in enhancing the sound amplitude. A shockproof mount commonly used in radio studios to reduce microphone vibration was essential in noise reduction for the TAC at high chopper wheel rotations. The sound amplitude was found to rapidly decrease with the increase in pulse frequency of the sunbeam at low frequencies. The relationship between the decibel value and frequency of the generated sound waves was changed to linear for sunbeam frequencies above 1 kHz. This is the frequency at which the penetration of surface temperature fluctuations into the aluminum housing becomes comparable with the aluminum housing thickness. At a given frequency, the sound amplitude increased almost exponentially with the increase in solar flux intensity. To the best of our knowledge, the 3 kHz sound frequency measured in our experiments is by far the highest frequency produced by a solar-to-acoustical energy converter.

본 연구는 주위의 온도보다 약 $20{\sim}30^{\circ}C$ 밖에 높지 않은 저온폐열을 활용하기 위한 TM(Thermal to Mechanical) 발전변환기의 개발을 위하여 저온도차 스털링엔진의 하나인 MM-7에 대한 성능실측 연구를 수행하였다. 스털링엔진의 흡열부와 방열부의 온도차에 대한 토크 및 분당회전수를 측정하고 이를 바탕으로 MM-7 엔진의 출력을 산출하였으며, 이를 통하여 효율적인 TM발전변환기의 개발 방안을 모색하였다. This study has been carried out to develop TM (Thermal to Mechanical) conversion systems for electric power generation using one of the Low Temperature Differential (LTD) Stirling engines called MM-7 capable of harnessing low temperature waste heat whose temperature is only $20{\sim}30^{\circ}C$ above the ambient. Measurements were made on the torque and rpm for a number of temperature differentials between the engine hot and cold ends, which could be effectively applied in developing the most suitable configuration for the high performance TM (Thermal to Mechanical) conversion system.

Generation of acoustic waves from a pulsed thermal radiation beam was experimentally investigated in this paper. Unlike other TACs (thermal acoustic converters), acoustic wave frequencies and phases of this type of TACs can be easily adjusted and controlled—a feature essential to the synchronization of TACs in an array. The TACs we developed were made up of a cylindrical aluminum housing, a glass cover, and metallic wool for effective thermal‐to‐acoustic energy conversion. Radiation emitted from an infrared heater was chopped at a constant frequency prior to entering the converter through the glass cover. The metallic wool was periodically heated by the pulsed radiation beam and cooled because of heat losses to the surroundings. Experiments were conducted for different converter designs and metallic wools, as well as different chopper speeds and radiation intensities. The amplitudes of generated sound waves were found to be dependent on the radiation intensity, the grade and properties of the metallic wool, and the cooling rate of the wool. Higher radiation intensities and thinner wools of lower thermal conductivity produced sounds of higher amplitude. More effective cooling of the metallic wool also helped. Acoustic energy output can also be enhanced by reducing the amount of air in the converter. Copyright © 2015 John Wiley & Sons, Ltd.

A small washer powered directly and solely by thermal radiation was constructed and tested to explore the feasibility of using solar energy or other types of thermal radiation for washing and cleaning. In principle, TA (ThermoAcoustic) washers have the benefits of simpler design and operation and fewer energy conversion processes, thus should be more energy efficient and cost less than electric washing/cleaning systems. The prototype TA converter we constructed could sustain itself with consistent fluid oscillations for more than 20 minutes when powered by either concentrated solar radiation or an IR (infrared) heater. The frequencies of water oscillations in the wash chamber ranged from 2.6 to 3.6 Hz. The overall conversion efficiency was lower than the typical efficiencies of TA engines. Change in water temperature had little effect on the oscillatory flow in the TA washer due to its low efficiency. On the other hand higher water temperatures enhanced grease removal considerably in our tests. Methods for measuring the overall conversion efficiency, frictional loss, and grease removal of the TA washing system we designed were developed and discussed.

Aerospace vehicles are continually being designed to sustain flight at higher speeds and higher altitudes than previously attainable. At hypersonic speeds, gases within a flow begin to chemically react and the fluid's physical properties are modified. It is desirable to model these effects within the Material Point Method (MPM). The MPM is a combined Eulerian–Lagrangian particle-based solver that calculates the physical properties of individual particles and uses a background grid for information storage and exchange. This study introduces chemically reacting flow modelling within the MPM numerical algorithm and illustrates a simple application using the AeroElastic Material Point Method (AEMPM) code. The governing equations of reacting flows are introduced and their direct application within an MPM code is discussed. A flow of 100% oxygen is illustrated and the results are compared with independently developed computational non-equilibrium algorithms. Observed trends agree well with results from an independently developed source.

The transient and synchronization behaviors of a TA (thermoacoustic) laser pair were investigated experimentally for various crossing angles and different separation distances between the laser openings. Sound waves generated by the lasers were measured and analyzed at or near the focusing point by means of microphones, SPL meters, and a commercial software called Signal-Express. The two TA lasers were acoustically coupled through the air mass between their openings, and the only mode-locking operation that could be achieved was the one that was nearly 180° out of phase. The time to achieve synchronization was found to be dependent upon the initial mistuning of the frequencies and the crossing angle between the laser axes. The synchronization process could also be accelerated by turning on the laser with the lower power input first.

The effects of geometric parameters (stack position, stack length, resonator tube length) and varying input power over acoustic energy output were investigated. The acoustic laser kit (Garret 2000) was used for the construction of TA lasers. A series of sound pressure level measurements in different orientations did not differ significantly confirming that the sound wave generated could be assumed as a spherical wave. An increase in acoustic pressure was recorded with respective increase in input power, stack and resonator tube lengths owing to their relative influence over heat transfer rate and critical temperature gradient across the stack.

In this work, we developed a facile and low-cost method with sufficient sensitivity for the quantitative determination of gold nanoparticles (GNPs) number concentration in water and fetal bovine serum solutions. The Au(III) digested from GNPs was reduced to Au(I) presumably by the thiol group of 2-mercaptobenzimidazole, then the Au(I)–thiolate complex was formed, the concentration of which is determined by absorbance at 300 nm. The number concentration of GNPs can be converted using microscopic images and simple calculations. The interference of serum can be avoided in this method. The limit of detection (LOD) of GNPs was calculated as 2.1 × 10−12 mol/L in water solution and 1.3 × 10−11 mol/L in fetal bovine serum (FBS) solution. This method provides a simple and fast way to determine the concentration of GNPs, which can be in carried out in the routine laboratory practice.

A simple and inexpensive radiation heat gauge was developed and tested for high-intensity thermal radiation measurements. The gauge used a thermal image camera to record the temperature variation of a metallic bar painted in black and heated at one end by thermal radiation. The average flux of the irradiation was determined from the rate of temperature change at a selected point on the bar. The aperture of the gauge can be easily varied by changing the diameter of the washer in front of the metallic bar. Numerical solutions were obtained for the transient heat conduction process in the metallic bar, and casted into dimensionless forms which can be conveniently used for bars of different sizes and materials, and/or subjected to different radiation fluxes. The gauge was employed to measure the radiation beams produced by a commercial IR (Infrared) heater and the results were in good agreement with the heater manufacturer's data.