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The transition metal-modified VWTi structural catalysts hold great promise for simultaneously removing nitrogen oxides (NOx) and volatile organic compounds (VOCs) from industrial flue gases. A series of Cu@VWTi catalysts were prepared to investigate their synergistic low-temperature removal performance towards NO and typical VOCs, including toluene, benzene, chlorobenzene (CB), p-chlorotoluene (p-CT), and dichloromethane (DCM). The copper-enhanced samples prepared via ultrasound-assisted impregnation exhibited irregular globular and varying crystallinity. The catalysts displayed a typical anatase crystal structure with high TiO 2 content or high dispersion of V and W species along with a certain adjustment effect on the morphology. Various controlling factors affecting the synergistic removal of NO and VOCs were evaluated. It was observed that the presence of VOCs in flue gas has weak impact on NO removal, except for the waste incineration using the Cu@VWTi catalyst. However, a high initial NO concentration had an adverse effect on VOCs removal. Impressively, the optimized copper-doped catalyst (5 wt% Cu loaded of smelting plant and coal-fired power plant used catalyst) exhibited excellent performance for p-CT, toluene and DCM removal of 95.0%, 99.6% and 100% at 300 °C, respectively. The toluene and p-CT conversion efficiencies were highest over the catalyst used in the smelting plant after Cu loading, surpassing the benzene conversion efficiency. Cu@VWTi demonstrated excellent performance for p-CT, toluene, and DCM removal at 250 °C. Although 5 wt% Cu loading on the catalysts significantly enhanced the stability and anti-jamming of VOCs removal, as well as their tolerance to both SO 2 and water vapor. The enhanced mechanism of Cu decoration attributed to the enhanced intensity of acid sites and the stable relative proportion of O ads /O latt species in the used 5% Cu loaded catalyst due to the redox cycles of Cu and V species. Compared with Brønsted acid, which primarily adsorbs NH4+, Lewis acid mainly adsorbs gas phase acid and forms coordinated NH 3 in gas phase. The bonding between toluene and the Cu site was enhanced with an adsorption energy of −130.9 kJ mol−1, as well as the cracking adsorption of the CH 2 Cl 2 on the Ti site with a bonding energy of −436.7 kJ mol−1, both indicating strong chemical adsorption. The first step of dechlorination and demethylation was thermodynamically and kinetically favorable for DCM and toluene decomposition. [Display omitted] • Cu@VWTi catalyst endorsed prospect for the simultaneous removal of NO/VOCs. • Cu@VWTi deliver excellent performance for p-CT, toluene, and DCM removal at 250 °C. • Cu-doping enhanced resistance to interference from SO 2 /H 2 O in typical VOCs removal. • Strong adsorbed acidic and unsaturated coordinate bond on catalyst surface was enhanced. • Dechlorination and demethylation process was favorable for DCM/toluene decomposition. [ABSTRACT FROM AUTHOR]

In this paper, a wide-range leaky-wave antenna with fast scanning rate and open-stopband (OSB) suppression based on microstrip spoof surface plasmon polaritons (MSSPPs) is proposed. First, the high-scanning-rate theory is analyzed. And based on the theory, the MSSPPs is used to radiate the fan beam rather than quasi-omnidirectional beam. In order to suppress the OSB, a capacitive slot is introduced using the proposed method of impedance matching. The prototype of the proposed antenna is fabricated and the measured results show that the antenna has 140° scanning range from −72° to 68° with the scanning rate of 8.8 and reflection coefficient lower than −10 dB in 8.7–10.2 GHz. [ABSTRACT FROM AUTHOR]

[Display omitted] • The generation characteristics of ABS/AS under non-catalytic conditions were investigated. • SO 3 and NH 3 enhanced ABS/AS generation and deposition. • The initial deposition temperature of ABS/AS is exponentially correlated with the product of SO 3 and NH 3 concentration. • Liquid ABS deposited firstly, the mixture of H 2 O, ABS and H 2 SO 4 or AS and (NH 4) 3 H(SO 4) 2 deposited at low temperature. The generation and deposition of ammonium bisulfate (ABS) in flue gas caused serious blockage and corrosion to the air preheater, which seriously affect the safe and economic operation of coal-fired power plants. The generation and deposition of ABS/ammonium sulfate (AS) under non-catalytic conditions were studied on a simulated air preheater test bench, and FT-IR and XRD tests were performed to characterize the products under different conditions. Experimental results show that the generation of ABS/AS is complicated and controlled by the concentration of SO 3 and NH 3 , the ratio of SO 3 to NH 3 (SO 3 /NH 3) and deposition temperature. Under the same SO 3 conditions, ABS/AS generation rate under different SO 3 /NH 3 conditions is 1:2 > 2:1 > 1:1. The initial deposition temperature of ABS/AS will increase with the corresponding increase of SO 3 and NH 3 concentration, and is exponentially correlated with the product of SO 3 and NH 3 concentration in flue gas. In the temperature range 390–223 °C, ABS generated and deposited under all conditions, and in the temperature range 223–131 °C, the mixture of H 2 O, H 2 SO 4 , and ABS generated and deposited when SO 3 /NH 3 is 2:1, and AS with a small amount of (NH 4) 3 H(SO 4) 2 generated and deposited when SO 3 /NH 3 is 1:1 and 1:2. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a 600 MWe Babcock & Wilcox boiler is selected as the research object. Numerical simulation and field experiments have been applied to this study under original and new combustion systems. The new approach mainly involves changing the operation mode of swirl burner, rearranging secondary air, and employing separated over-fire air. Numerical results showed that NO x emissions and the unburned combustible in flue dust decrease with the arrangement of the swirl burner changing from co-rotating mode to counter-rotating one. Consequently, counter-rotating mode of adjacent burners was chosen as the optimized arrangement. The introduction of separated over-fire air resulted in a remarkably reduction of the NO x emissions, which reduced from 1085 mg/m3 to 547 mg/m3. With increase of the distance between separated over-fire air and arch from 0.5 m to 3.0 m, NO x emissions changed slightly and the unburned combustible in flue dust were not greatly affected. When the distance continued increase to 6.0 m, NOx generation was suppressed and boiler efficiency declined. Considering the economic efficiency and NOx emissions reduction, the optimal sofa position is 3.0 m above the arch. In situ measurement results are consistent with the modelling predictions This work provides a feasible and economic approach for Babcock & Wilcox down-fired boilers to achieve high efficiency and low pollutant emissions. Highlights • Study the effects of burner rearrangement on low-nitrogen combustion. • Accurate calculate carbon content in fly ash by using CBK model. • Optimize the combustion system based on numerical simulations. • NOx at furnace exit decrease from 1085 mg/m3 to 547 mg/m3 by introduce SOFA. [ABSTRACT FROM AUTHOR]

[Display omitted] • The deposition and transformation of ammonium bisulfate (ABS) on fly ash under variable temperature conditions was investigated. • Fly ash enhanced ABS deposition by trapping and absorbing effects. • ABS deposition is positively correlated with the product of SO 3 and NH 3. • Along the flow direction of flue gas in the air preheater, the deposited products will gradually convert from ABS to the mixture of ABS and H 2 SO 4. • ABS will convert into sulfate with higher decomposition temperature on fly ash. Ammonium bisulfate (ABS) aggravates the corrosion and plugging of air preheaters, resulting in unplanned outages and expensive cleaning. Understanding its deposition and transformation process is important for the development of ABS control strategies. A multistage temperature control system was built to simulate the temperature gradient in the air preheater and the deposition and transformation of ABS in the presence of fly ash were studied using Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetry. The presence of fly ash increases both the deposition amount and the temperature of ABS in the 25–200 ppm SO 3 concentration range; the initial ABS deposition temperature is between 202 and 290 ℃ and most likely occurs in the 230–250 ℃ range. The main product was ABS, and its formation temperature was much higher than the deposition temperature observed in the experiment. In the 224–180 ℃ range, the products gradually changed from ABS to sulfuric droplets. Fly ash has trapping and adsorbing effects on the gas-phase ABS in flue gas, and more ABS is captured at high temperatures owing to the higher concentrations of reactants. ABS deposition leads to the accumulation and adhesion of fly ash particles and reacts with the fly ash to convert it into a variety of ammonium salts and sulfates with higher decomposition temperatures. Compared with the sulfate formed after the deposition of sulfuric acid droplets, the sulfate formed by ABS conversion had a lower relative decomposition temperature. [ABSTRACT FROM AUTHOR]

Background and purpose This study is to determine if the overlap-volume histogram (OVH)-driven planning methodology can be adapted to robotic SBRT (CyberKnife Robotic Radiosurgery System) to further minimize the bladder and rectal doses achieved in plans manually-created by clinical planners. Methods and materials A database containing clinically-delivered, robotic SBRT plans (7.25 Gy/fraction in 36.25 Gy) of 425 patients with localized prostate cancer was used as a cohort to establish an organ’s distance-to-dose model. The OVH-driven planning methodology was refined by adding the PTV volume factor to counter the target’s dose fall-off effect and incorporated into Multiplan to automate SBRT planning. For validation, automated plans (APs) for 12 new patients were generated, and their achieved dose/volume values were compared to the corresponding manually-created, clinically-delivered plans (CPs). A two-sided, Wilcoxon rank-sum test was used for statistical comparison with a significance level of p < 0.05. Results PTV’s V (36.25 Gy) was comparable: 95.6% in CPs comparing to 95.1% in APs ( p = 0.2). On average, the refined approach lowered V (18.12 Gy) to the bladder and rectum by 8.2% ( p < 0.05) and 6.4% ( p = 0.14). A physician confirmed APs were clinically acceptable. Conclusions The improvements in APs could further reduce toxicities observed in SBRT for organ-confined prostate cancer. [ABSTRACT FROM AUTHOR]

In this letter, a simple approach to design a reconfigurable feeding network (RFN) for antenna array beam scanning is presented. By combining a 3 dB power divider and a reconfigurable delay line group (RDLG), the two output signals with 2 m+n sets of uniformly distributed phase gradients (PGs) can be obtained. And by adopting multi two-output RFNs and multi-stage design, a RFN for generating 2 m+n continuously distributed beams is constructed. For verifying the design method, a microstrip four-output RFN for generating four scanning beams is implemented, fabricated and measured. The measured results are consistent with the theoretical analysis, which provides the validity of the design. And the design of the RFN can be used as a candidate of the feeding network for antenna array beam scanning. [ABSTRACT FROM AUTHOR]

Highlights: [•] MnO x –CeO2–ZrO2/γ-Al2O3 catalyst showed high SCR activity at low temperature. [•] MnO x –CeO2–ZrO2/γ-Al2O3 catalyst was well-behaved in the presence of SO2 and H2O. [•] NO and NH3 could be adsorbed on the catalyst in different forms. [•] The SCR reaction route followed both of the E–R mechanism and L–H mechanism. [Copyright &y& Elsevier]

Abstract: Currently, selective catalytic reduction (SCR) of NO x with NH3 has been widely applied to reduce the emission of nitrogen oxides from mobile and stationary sources. But the detailed SCR reaction mechanism is still controversial and lacks the related comparative study of molecule modeling. The SCR reaction belongs to the gas–solid multiphase reaction, in which the adsorption of NH3 and NO by the catalysts plays an important role. In the present study, the adsorption properties of NH3 and NO on both the dry and partially hydroxylated γ-Al2O3 (110) surfaces supported CuO were revealed using the density-function theory (DFT) calculations. The results showed that NH3 could be adsorbed strongly on the dry (110) surface in the form of coordinated NH3 and NH4 +. Some of the coordinated NH3 could then undergo H-abstraction and form the –NH2 species. NO could be adsorbed weakly on the dry surface, and could also be adsorbed as bidentate nitrates or bridged nitrites. However, the adsorption activation of NH3 and NO on the partially hydroxylated surface was much weaker. The results of the DFT calculations are in good agreement with the experimental results and provided detailed clues to understand the adsorption mechanism of NH3 and NO on the CuO/γ-Al2O3 catalysts. [Copyright &y& Elsevier]