N2O is a common byproduct in the NH3-SCR reaction. We analyzed the N2O formation pathways in NH3-SCR over various catalysts (Cu-ZSM-5, Fe-ZSM-5, Cu-SAPO-34, Fe-SAPO-34, Cu-SSZ-13, and Fe-SSZ-13), ...aided by catalyst characterization using XRD, XPS, EDS mapping, and NH3-TPD. The results showed that the NH3 nonselective catalytic reduction was the major N2O formation pathway for most of the Cu catalysts. The N2O formation at lower temperatures (<300 °C) originated mainly from decomposition of NH4NO3. In addition, NH3 nonselective oxidation was another reaction that formed N2O especially at higher temperatures. The N2O resulting from the Eley–Rideal mechanism was also favored at higher temperatures. The decomposition of NO to N2O and O2 also led to N2O formation, although its contribution was minimal. The absence of N2O yield over most Fe catalysts could be attributed to active N2O decomposition and N2O-SCR reactions. Moreover, varying O2 and H2O concentrations in the feed exerted strong influence on both N2O formation and SCR activity. Decrease in O2 level from 14% to 3% led to continual decline in N2O formation but had no effect on SCR activity until reaching a threshold concentration of 2%. H2O in lower concentrations (2–3%) facilitated N2O formation and NO conversion due to increase in Brønsted acidity, while H2O in higher concentrations (>5%) led to suppression of these reactions due to the coverage of active sites.
Reinforced concrete (RC) buildings are commonly used around the world. With recent earthquakes worldwide, rapid structural damage inspection and repair cost evaluation are crucial for building owners ...and policy makers to make informed risk management decisions. To improve the efficiency of such inspection, advanced computer vision techniques based on convolutional neural networks have been adopted in recent research to rapidly quantify the damage state (DS) of structures. In this article, an advanced object detection neural network, named YOLOv2, is implemented, which achieves 98.2% and 84.5% average precision in training and testing, respectively. The proposed YOLOv2 is used in combination with the classification neural network, which improves the identification accuracy for critical DS of RC structures by 7.5%. The improved classification procedures allow engineers to rapidly and more accurately quantify the DSs of the structure, and also localize the critical damage features. The identified DS can then be integrated with the state‐of‐the‐art performance evaluation framework to quantify the financial losses of critical RC buildings. The results can be used by the building owners and decision makers to make informed risk management decisions immediately after the strong earthquake shaking. Hence, resources can be allocated rapidly to improve the resiliency of the community.
High entropy alloys (HEAs) with a face-centered cubic (fcc) structure have received an increasing attention in recent years due to their exceptional ductility and fracture toughness. On the other ...hand, they generally show lower strengths at ambient and elevated temperatures. In this review, we attempt to highlight recent advances in the design of computation-aided HEAs being alloyed with Al, Al/Ti, Nb and Mo additions on the precipitation hardening behavior of this fcc-type CoCrFeNi alloy, and to summarize the corresponding mechanical properties of the newly developed precipitation-strengthened HEAs under different thermomechanical processing. In particular, our emphasis is played on elucidating the correlation between precipitation behaviors and mechanical properties, which may serve as a demonstrative summary for the current progress in the scientific research of precipitation-strengthened HEAs. Finally, future research areas for these precipitation-strengthened HEAs are critically assessed.
Radionecrosis is a well-characterized effect of stereotactic radiosurgery (SRS) and is occasionally associated with serious neurologic sequelae. Here, we investigated the incidence of and clinical ...variables associated with the development of radionecrosis and related radiographic changes after SRS for brain metastases in a cohort of patients with long-term follow up. 271 brain metastases treated with single-fraction linear accelerator-based SRS were analyzed. Radionecrosis was diagnosed either pathologically or radiographically. Univariate and multivariate Cox regression was performed to determine the association between radionecrosis and clinical factors available prior to treatment planning. After median follow up of 17.2 months, radionecrosis was observed in 70 (25.8 %) lesions, including 47 (17.3 %) symptomatic cases. 22 of 70 cases (31.4 %) were diagnosed pathologically and 48 (68.6 %) were diagnosed radiographically. The actuarial incidence of radionecrosis was 5.2 % at 6 months, 17.2 % at 12 months and 34.0 % at 24 months. On univariate analysis, radionecrosis was associated with maximum tumor diameter (HR 3.55, p < 0.001), prior whole brain radiotherapy (HR 2.21, p = 0.004), prescription dose (HR 0.56, p = 0.02) and histology other than non-small cell lung, breast or melanoma (HR 1.85, p = 0.04). On multivariate analysis, only maximum tumor diameter (HR 3.10, p < 0.001) was associated with radionecrosis risk. This data demonstrates that with close imaging follow-up, radionecrosis after single-fraction SRS for brain metastases is not uncommon. Maximum tumor diameter on pre-treatment MR imaging can provide a reliable estimate of radionecrosis risk prior to treatment planning, with the greatest risk among tumors measuring >1 cm.
In this paper, we present a system design for single-input-multiple-output (SIMO) orthogonal frequency-division multiplexing (OFDM) communications over underwater acoustic (UWA) channels. The design ...targets at improving bandwidth efficiency by reducing the amount of overheads (e.g., guard time intervals, training/pilot symbols) typically associated with SIMO-OFDM UWA communications. The design consists of three key components: preamble-based parameter estimation that exploits full knowledge of the preamble; time-reversal-based symbol detection that enables the use of short guard time intervals for interblock interference avoidance; and decision-directed (DD) channel tracking with error propagation (EP) control that eliminates the need of periodic training for channel tracking. The proposed design is analyzed and tested at a seagoing experiment. The experimental results confirm the merits of our design and demonstrate considerable improvements over a competing alternative.
Cabozantinib, an orally bioavailable inhibitor of tyrosine kinases including MET, AXL, and VEGF receptors, was assessed in patients with hepatocellular carcinoma (HCC) as part of a phase 2 randomized ...discontinuation trial with nine tumor-type cohorts.
Eligible patients had Child-Pugh A liver function and ≤1 prior systemic anticancer regimen, completed ≥4 weeks before study entry. The cabozantinib starting dose was 100 mg daily. After an initial 12-week cabozantinib treatment period, patients with stable disease (SD) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0 were randomized to cabozantinib or placebo. The primary endpoint of the lead-in stage was objective response rate (ORR) at week 12, and the primary endpoint of the randomized stage was progression-free survival (PFS).
Among the 41 HCC patients enrolled, the week 12 ORR was 5%, with 2 patients achieving a confirmed partial response (PR). The week 12 disease control rate (PR or SD) was 66% (Asian subgroup: 73%). Of patients with ≥1 post-baseline scan, 78% had tumor regression, with no apparent relationship to prior sorafenib therapy. Alpha-fetoprotein (AFP) response (>50% reduction from baseline) occurred in 9 of the 26 (35%) patients with elevated baseline AFP and ≥1 post-baseline measurement. Twenty-two patients with SD at week 12 were randomized. Median PFS after randomization was 2.5 months with cabozantinib and 1.4 months with placebo, although this difference was not statistically significant. Median PFS and overall survival from Day 1 in all patients were 5.2 and 11.5 months, respectively. The most common grade 3/4 adverse events, regardless of attribution, were diarrhea (20%), hand-foot syndrome (15%), and thrombocytopenia (15%). Dose reductions were utilized in 59% of patients.
Cabozantinib has clinical activity in HCC patients, including objective tumor responses, disease stabilization, and reductions in AFP. Adverse events were managed with dose reductions.
NCT00940225.
A proposed Internet of Things system architecture offers a solution to the broad array of challenges researchers face in terms of general system security, network security, and application security.
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