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Anthropogenic emission of CH4 and CO2 contributes for most of global warming. Hence, simultaneous conversion of CH4 and CO2 into syngas (dry reforming of methane) can be a promising way to alleviate climate change. In this work, we developed a series of perovskite-type photocatalysts, based on LaFeO3 with various calcination temperatures to combine with a spark discharge reactor to form a hybrid plasma photocatalysis reactor. The hybrid reactor is applied for dry reforming of methane to investigate the syngas generation rate and to reveal possible interactions between plasma and photocatalyst. Results show that LFO600-packed bed has the best CH4 and CO2 conversions and syngas generation efficiency of 53.6%, 40.0% and 18.4 mol/kWh, respectively. The enhancement of syngas generation rate can be attributed to synergies between LFO and plasma. Furthermore, changing calcination temperature of photocatalyst also leads to variable characteristics of photocatalyst and hence plasma photocatalysis performance for syngas production.

Large amount of volatile organic compounds (VOCs) are emitted from industrial, mobile, and domestic sources, causing adverse effects on human health and environment. Among VOCs, toluene and isopropanol (IPA) are commonly used as solvent, soldering flux, and spray paint and their emissions need to be reduced. Several VOCs abatement technologies are available to reduce VOC emission and photocatalytic oxidation of VOC is regarded as a viable technique due to its advantage of utilizing solar energy. TiO2 has been investigated for its oxidation capability toward VOCs because of its good photocatalytic activity. However the utilization is limited to UV due to its wider bandgap; furthermore, its fast recombination rate of electron-hole pair reduces the oxidation rate of VOCs. Black-TiO2 and perovskite-type photocatalyst such as LaFeO3 can be applied to enhance photocatalytic activity due to narrower bandgap and longer electron-hole pair lifetime. In this study, black-TiO2 and LaFeO3 are prepared and investigated for their photocatalytic oxidation rates toward toluene and IPA. Results show that toluene removals achieved with black-TiO2 and LaFeO3 are 89% and 98% while IPA removals are 90% and 94%, respectively. Both photocatalysts show better photocatalytic activity than TiO2 and good absorption capability toward visible light.

We have revealed that cubelike and hexarhombic docadehedron-like Cu single crystals showed an enhancement of C2 products (ethylene and ethanol) while octahedron-like Cu nanoscale single crystals pr...

As concern has increased regarding the interaction between efficiency and safety of disinfection, plasma becomes a viable alternative for disinfection in comparison with traditional methods. Dielectric barrier discharge (DBD) is applied to deactivate

How to effectively reduce anthropogenic greenhouse gases emission to alleviate global warming has been a public concern since 20th century. Hence, development of effective CO2 and CH4 reduction technique is a common objective worldwide. Simultaneous conversion of CO2 and CH4 into syngas can be a candidate to achieve the objective. Among several conversion techniques, plasma and photocatalysis are two promising techniques possessing good potentials. In this work, a spark discharge reactor and a series of perovskite-type photocatalysts are developed and combined to form hybrid plasma photocatalysis systems to evaluate the effectiveness for converting CO2 and CH4 to form syngas. Experimental results indicate that the spark discharge reactor packed with LFO600 photocatalyst increases the syngas generation rate from 13.0 to 18.5 mol per kilowatt-hour, corresponding to 42% of enhancement. Furthermore, characterizations of photocatalysts reveal that plasma can promote the surface structure of photocatalyst to increase the lifetime of electron-hole pairs which possibly leads to higher syngas generation rate. Additionally, the hybrid plasma photocatalysis system developed has been demonstrated with good potential to improve plasma and photocatalysis performances.

Although perovskite solar cells have achieved extremely high performance in just a few years, their device stability and fabrication cost are still of great concern. For inverted p–i–n perovskite solar cells, the commonly used electron-transporting layers are C60 and PCBM, which have stability issues and are very expensive. Here, we report a novel and highly stable perovskite solar cell using an inorganic electron-transporting layer made of microwave-assisted solution-processed indium-doped zinc oxide (IZO) nanoparticles. With NiO as the hole-transporting layer, the perovskite solar cells with all-inorganic selective contacts demonstrate a decent power conversion efficiency of over 16%. More importantly, the IZO-based perovskite solar cells demonstrate impressive long-term stability under air or light-soaking conditions. With encapsulation, our device retained 85% of the initial power conversion efficiency after 460 hours of light soaking. This result reveals that good device performance, low fabrication cost and impressive light-soaking stability can be realized simultaneously by employing facile microwave-synthesized oxides (IZO and NiO in this work) as inorganic selective contacts.

Application of atmospheric-pressure spark discharge plasma for conversion of the two most important anthropogenic greenhouse gases (GHGs) into valuable products, including syngas and multiwalled carbon nanotubes (MWCNTs), is experimentally evaluated. Syngas with different CO/H2 ratios and MWCNTs with different physicochemical properties can be generated by varying the CO2/CH4 feeding ratio from 0 to 3. Operating spark discharge with pure CH4, the reactor generates syngas with the lowest rate and MWCNT without oxygen-containing functional groups. Introducing an appropriate amount of CO2 into plasma results in higher syngas and MWCNT generation rates. To achieve the highest syngas generation rate, a CO2/CH4 ratio of 1 is suggested, while for the highest MWCNTs generation, a CO2/CH4 ratio of 1/3 is favored. Moreover, the physicochemical properties of the MWCNTs generated are influenced via controlling the CO2/CH4 ratio, and various characteristic properties of MWCNTs may provide different applications. Overa...

An optical fiber sensing system integrating a fiber Bragg grating (FBG) sensor, a long-period fiber grating (LPFG) optical filter and a photodetector is presented to monitor the dynamic response of a structure subjected to base excitation and impact loading. The FBG sensor is attached to a test specimen and connected to an LPFG filter. As the light reflected from the FBG sensor is transmitted through the long-period fiber grating filter, the intensity of the light is modulated by the wavelength, which is affected by the strain of the FBG. By measuring the intensity of the light using a photodetector, the wavelength reflected from the FBG sensor can be demodulated, thus leading to the determination of the strain in the structure. To demonstrate its effectiveness, the proposed sensing system was employed to measure the dynamic strain of a beam subjected to mechanical testing. The mechanical tests comprised three load scenarios: base excitation by a shaker at resonant frequency, impact loading by a hammer and shock test on a drop table. To monitor the dynamic strain during the test and validate the accuracy of the measurement of the FBG sensor, strain gauge was used as reference. Experimental results show good correlation between the measurements of FBG sensor and strain gauge. The present work provides a fast response and easy-to-implement optical fiber sensing system for structural health monitoring based on real-time dynamic strain measurements.

Biogas can be an energy carrier and on-site conversion of biogas into syngas provides an alternative to reduce its utilization cost and to increase its energy density since CO2 can be converted into combustible contents. In this study, perovskite-type photocatalyst LaFeO3 (LFO) and Ag-LaFeO3/TiO2 (ALFTO) are prepared and combined with a spark discharge reactor to conduct biogas reforming. Next, to reduce the influence of H2S on reforming system, another photocatalyst BaTa0.7Nb0.3O3 (BTaNO) is added to form plasma Z-scheme photocatalysis system. Results indicate that packing ALFTO enhances syngas generation rate to 20.2 mol/kW h but the existence of H2S leads to deactivation of photocatalyst and restriction on discharge. Further introduction of BTaNO increases the stable discharge time of the reactor. Photocatalyst characterizations further indicate that there are interactions between plasma and photocatalyst to induce synergistic effects and Z-scheme photocatalysis is beneficial to alleviate the impact of H2S on biogas reforming.

This study proposes to make protective vests with X-ray shielding effectiveness. X-ray shielding powders are coated onto sandwich air mesh fabrics (SAMF), which are then coated with another layer of powders to form a continuous surface; thus forming double-layer X-ray shielding fabric. The tensile strength of SAMF is first evaluated, after which a stereomicroscope and scanning electron microscope (SEM) observe the X-ray shielding fabric and double-layer X-ray shielding fabrics. Next, an X-ray shielding effect test measures them. The double-layer X-ray shielding fabrics are then tailored into X-ray shielding protective vests using vest patterns. The test results show that the X-ray shielding powders can combine well with SAMF by using urethane resin, and as a result, the X-ray shielding effectiveness is proportional to the content of the powders. The double-layer X-ray shielding fabrics exhibit an optimal X-ray shielding effectiveness due to their double-layer structure. The combination of SAMF provides flexibility to the protective vest regardless of the coating of X-ray shielding powders.

Indium-nitrogen co-doped zinc oxide thin films (INZO) were prepared on glass substrates in the atmosphere by ultrasonic spray pyrolysis. The aqueous solution of zinc acetate, ammonium acetate and different indium sources: indium (III) chloride and indium (III) nitrate were used as the precursors. After film deposition, different anneal temperature treatment as 350, 450, 550oC were applied. Electrical properties as concentration and mobility were characterized by Hall measurement. The surface morphology and crystalline quality were characterized by SEM and XRD. With the activation energy analysis for both films, the concentration variation of the films at different heat treatment temperature was realized. Donors correspond to zinc related states dominate the conduction mechanism for these INZO films after 550oC high temperature heat treatment process.

A hybrid plasma catalytic system consisting of a dielectric barrier discharge (DBD) reactor and relaxor ferroelectrics is investigated for syngas generation via the carbon dioxide reforming of methane. The study tests three kinds of packing materials, including two relaxor ferroelectrics BaZr0.75T0.25O3 (BZT; er = 149), BaFe0.5Nb0.5O3 (BFN; er = 2025), and glass beads (er = 3–5). The BFN and BZT packed-bed DBD reactors achieve higher CO2 and CH4 conversions and better energy efficiencies for syngas production than the DBD. On the contrary, the DBD packed with glass beads achieves lower conversions and energy efficiencies than the DBD. In terms of packings filled in a DBD reactor, there is a trade-off between an enhancement of the electric field strength and a reduction of the gas retention time. It is interesting that the conversions are increased with the increase of the dielectric constant of the packings tested in the study. Overall, a relaxor ferroelectric with a high dielectric constant is a good can...

The hybrid plasma catalysis system was investigated for dry reforming of methane (DRM) with CO 2 to form syngas. First, dielectric barrier discharge (DBD) alone was evaluated for the effectiveness in conversion of CO 2 and CH 4 , and with the applied voltage of 15.0-19.5 kV, and frequency of 200 Hz. The ratio of feeding gas (CH 4 /CO 2 ) and total gas flow rate were controlled at 1 and 40 mL/min, respectively. The results indicate that conversions of CO 2 and CH 4 significantly increase with increasing applied voltage. The conversion of both greenhouse gases (CO 2 and CH 4 ) achieved the maximum value of 18.9% and 24.0%, respectively, at applied voltage of 19.5 kV. Selectivity of CO decreases from 53.6% to 42.4% as applied voltage is increased from 15.0 to 19.5 kV, while selectivity of H 2 increases from 30.1% to 35.8%. In addition, the influences of gas flow rate and ratio of feeding gas were also explored for DBD-alone system, and the results indicate that energy efficiency of syngas generation can be significantly increased as the flow rate is increased. As a catalyst with a high dielectric constant is placed into the discharge zone, the conversions of two gases (CO 2 and CH 4 ) reach 27.3% and 31.2%, respectively, at applied voltage of 19.5 kV. Selectivity of CO decreases from 59.4% to 49.6% as applied voltage is increased from 15 to 19.5 kV, while selectivity of H 2 increases from 32.0% to 38.3%. In the meantime, energy efficiency of syngas generation is increased by 0.3%. Overall, this paper indicates that combining DBD with a catalyst of high dielectric constant is a viable process for DRM.

To assist endodontic therapy, in this paper, a force sensor is designed and fabricated for measuring the axial force and the bending moment simultaneously. By detecting the bending moment, we can know the severity of bending. Axial force detection is also desired, as excessive axial forces may result in instrument buckling or even root canal perforation. This paper installs three sensing cells in each of two planes to detect the bending direction. Each sensing cell consists of a pressure-sensitive electric conductive rubber and an electrode. The size of the force sensor is 1.4-mm wide and 6-mm high for matching the size of endodontic instruments and making it feasible in the endodontic treatment. Experimental results on accuracy, repeatability, and nonlinearity are presented to validate the proposed sensor.

Highly ordered TiO 2 nanotube arrays (TNA) have been synthesized by anodization of Ti foils using an established electrochemical process. The parameters such as anodization potentials and durations have been varied to fabricate the specific morphology of TNA. In addition, Pt nanoparticles were deposited on these TNA via microwave irradiation. The photocurrent density–voltage ( J – V ) properties induced by the standard AM 1.5 solar simulator have been characterized using a potentiostat meter. The efficiency of photoelectrocatalytic effect of the large-pore-sized TNA (=120 nm) is found to be higher than those of the TNA in smaller pore sizes (≤100 nm). TNA with smaller pore sizes exhibit lower surface areas, and therefore, inferior photo-current efficiency to those of TNA with larger pore sizes. The low surface area of smaller-pore-sized TNA was resulted from the shorter tube length obtained at smaller anodizing voltages. Deposition of Pt nanoparticles on TNA was successfully accomplished using microwave irradiation technique. An enhanced hydrogen generation rate of 0.613 ml h −1 cm −2 (≅25.0 μmol h −1 cm −2 ) was obtained on these Pt-deposited TNA compared to the 0.313 ml h −1 cm −2 (≅12.8 μmol h −1 cm −2 ) of pristine TNA in a solution of methanol and water (1:1 ratio).

In this article, we apply indium zinc oxide (IZO) transparent conductive oxide film for the fabrication of bifacial-illuminated perovskite solar cells (PSCs) and two substrate type PSCs based on non-fluorine-doped tin oxide (FTO) and ultrathin substrates. The Si/perovskite tandem solar cell system employing bifacial-illuminated PSCs delivers a decent power conversion efficiency (PCE) of 19.51% with 1 cm2 active area. The investigation of PSCs without FTO substrate is further demonstrated using sputtered Ti metal as a substrate. The devices employing a Ti cathode coating on a slide and ultrathin glass could deliver 13.5% and 13.6% of PCE, respectively, revealing a promising application for cost-effective and light-weight non-FTO devices.

The effect of oxygen (O) content on the electrical properties of physical-vapor-deposited nickel oxide (PVD-NiO) was studied. When the NiO target was sputtered, introducing O2 can lead to the formation of Ni3+ ions in the deposited film. These Ni3+ ions can act as acceptors. However, there were too many Ni3+ ions that were obtained following the introduction of O atoms. It resulted in intensive p-type conduction and made the O2-introduced PVD-NiO behave as a conductor. Thus, it was possible to reduce the O content of PVD-NiO to obtain a p-type semiconductor. In this study, a transparent PVD-NiO film with a carrier concentration of 1.62 × 1017 cm−3 and a resistivity of 3.74 Ω cm was sputter-deposited within pure argon plasma. The thin-film transistor (TFT) employing this proposed PVD-NiO can result in good current switching, and even operated at very low drain–source voltage. The ON/OFF current ratio, field-effect carrier mobility, and threshold voltage of the proposed NiO TFT were 3.61 × 104, 1.09 cm2 V−1 s−1 and −3.31 V, respectively.

An electrochemical method of preparing chitosan scaffolds with three different molecular weights in various acid solutions has been reported. Chitosan samples prepared by electrolysis in acid solutions exhibited a rod-like geometry and a porous morphology with detectable deacetylation and degradation. The recovery rate of high molecular weight chitosan was highest among three polymers in all type of solvents. Specific gravity, crystallinity, and the morphology of various scaffolds were investigated by pycnometer, X-ray, and scanning electron microscopy studies. These evidences indicated that chitosan scaffolds lost some degree of crystallinity and showed a porous structure. The process and structures described here provided a starting point for the fabrication and design of chitosan based scaffold materials.

The vertically orientated TiO2 nanotube array (TNA) decorated with TiO2 nano-particles was successfully fabricated by electrochemically anodizing titanium (Ti) foils followed by Ti-precursor post-treatment and annealing process. The TNA morphology characterized by SEM and TEM was found to be filled with TiO2 nano-particles interior and exterior of the TiO2 nano-tubes after titanium (IV) n-butoxide (TnB) treatment, whereas TiO2 nano-particles were only found inside of TiO2 nano-tubes upon titanium tetrachloride (TiCl4) treatment. The efficiency in TNA-based DSSCs was improved by both TnB and TiCl4 treatment presumably due to the increase of dye adsorption.

Dye-sensitized solar cells (DSSCs) are a relatively low cost solar cell technology with an overall light-to electricity conversion efficiency of over 10%. Typically, a ∼10 μm thickness of TiO 2 nanocrystalline film was used in DSSC devices for the purpose of electron collection and transportation. In this work, the TiO 2 nanotube array (TNTA) covered with TiO 2 nanoparticles (TNP) were successfully prepared by anodization of Ti foil followed by Ti-precursor treatment and annealing process. The TNTA-based DSSCs were fabricated for photovoltaic characterization studies. It was found that the post-treated TNTAs-TNP enhanced the photoconversion efficiency for ∼26% over the DSSC fabricated by TNTAs, presumably due to both the increase of dye adsorption and electron transportation rate.

Titanium dioxide (TiO2) paste was prepared by sol-gel and hydrothermal method with various precursors. Nanostructured mesoporous TiO2thin-film back electrode was fabricated from the nanoparticle colloidal paste, and its performance was compared with that made of commercial P25 TiO2. The best performance was demonstrated by the DSSC having a 16 μm-thick TTIP-TiO2back electrode, which gave a solar energy conversion efficiency of 6.03%. The ability of stong adhesion on ITO conducting glass substrate and the high surface area are considered important characteristics of TiO2thin film. The results show that a thin film with good adhesion can be made from the prepared colloidal paste as a result of alleviating the possibility of electron transfer loss. One can control the colloidal particle size from sol-gel method. Therefore, by optimizing the preparation conditions, TiO2paste with nanoparticle and narrow diameter distribution was obtained.

Metal scrap is a major waste generated from the decommissioning of nuclear facilities. Through a decontamination process, most of the metal scraps can be cleaned to meet the clearance levels, which can then be reused or released according to the regulatory procedure. Usually, chemical processes will be used in the cleaning step. Phosphoric acid and fluoroboric acid are the typical chemicals used for decontamination. Although the decontaminant could be reused multiple times after regeneration, its decontamination efficiency would decrease after 3 to 5 cycles. In addition, the radioactive nuclides such as Cs-137 are not easily removed during the regeneration process; it tends to accumulate slowly in the decontaminant. According to the ALARA principle, decontaminant must be replaced if its radioactive activity exceeds the regulatory levels. As a result, a significant amount of spent strong acid solution would be generated. The conventional way of treatment is to neutralize the acid solution with an alkaline solution. However, such method will produce a large amount of sludge that requires further stabilization, which offsets the advantages of metal decontamination by use of the decontaminant. A high-efficiency solidification method has been developed and used to treat the spent phosphoric acid and fluoroboric acid solution in Institute of Nuclear Energy Research (INER). The self-polymerization nature of highly concentrated phosphoric acid is adopted to immobilize the radioactive nuclides. The volume of solidified form is almost equal to that of the treated acid solution. The waste form demonstrates its quality by compression test and leaching test. This cementation process is an excellent method to minimize the secondary waste, which is generated from chemical decontamination for treating metal waste.Copyright © 2011 by ASME

Highly-ordered TiO 2 nanotube arrays (TNA) by anodizing Ti foil were carried out using a slightly modified electrochemical process. The parameters such as anodization potentials and duration have been varied in order to fabricate the specific length and diameter of TNA. The morphologies of TNA were characterized by field emission scanning electron microscope (Hitachi S-4100 FE-SEM). The crystalline phase and structure were analyzed using X-ray diffraction (Rigaku, XRD). The processing anodic current density with time was recorded by Keithley 2400. The photocurrents induced by UV-light were characterized by CHI 611. The performance of hydrogen production from photoelectrocatalytic effect of larger diameter TNA is found to be higher than the smaller diameter TNA. Base on the microstructure and calculation, we confirmed that larger diameter TNA do exhibit higher surface area.

With the optimization of sulfate-free cleaning the issue of haze under pellicle was almost eliminated. In consequence, current reasons for mask repelliclization needs are moving from pattern issues to more gross problems on back glass. Moreover, the longer life of photomasks allows a new problem to appear as growing defects on back glass, commonly ascribed to environmental conditions at user's site. The commonality of these problems is being independent on mask complexity and substrate. In order to avoid the criticalities of pellicle removal and cleaning treatment as well as the cost of necessary inspection after new pellicle application, the best solution is cleaning only the backside of the mask, provided that integrity of pellicle and pattern on front side are preserved In this article we present the results obtained by the use of the Mask cleaner DE050019TM on several cases. The efficiency of the treatment was assessed in terms if removal capability on different kinds of contaminations, either from use or mask aging. Pattern inspections were conducted in order to assess ESD robustness. Ionic residues were checked by IC aimed to compare with standard cleanings. This methodology demonstrated to be capable of maintaining a Particle Removal Efficiency>97% on all kinds of contaminations, without any damage to pellicle or harm to patterns, still maintaining residual ions at the same level as after cleaning by standard tools.