Recent trends in vanadium-based SCR catalysts for NOx reduction in industrial applications: stationary sources.

Vanadium-based catalysts have been used for several decades in ammonia-based selective catalytic reduction (NH3-SCR) processes for reducing NOx emissions from various stationary sources (power plants, chemical plants, incinerators, steel mills, etc.) and mobile sources (large ships, automobiles, etc.). Vanadium-based catalysts containing various vanadium species have a high NOx reduction efficiency at temperatures of 350-400 °C, even if the vanadium species are added in small amounts. However, the strengthening of NOx emission regulations has necessitated the development of catalysts with higher NOx reduction efficiencies. Furthermore, there are several different requirements for the catalysts depending on the target industry and application. In general, the composition of SCR catalyst is determined by the components of the fuel and flue gas for a particular application. It is necessary to optimize the catalyst with regard to the reaction temperature, thermal and chemical durability, shape, and other relevant factors. This review comprehensively analyzes the properties that are required for SCR catalysts in different industries and the development strategies of high-performance and low-temperature vanadium-based catalysts. To analyze the recent research trends, the catalysts employed in power plants, incinerators, as well as cement and steel industries, that emit the highest amount of nitrogen oxides, are presented in detail along with their limitations. The recent developments in catalyst composition, structure, dispersion, and side reaction suppression technology to develop a high-efficiency catalyst are also summarized. As the composition of the vanadium-based catalyst depends mostly on the usage in stationary sources, various promoters and supports that improve the catalyst activity and suppress side reactions, along with the studies on the oxidation state of vanadium, are presented. Furthermore, the research trends related to the nano-dispersion of catalytically active materials using various supports, and controlling the side reactions using the structure of shaped catalysts are summarized. The review concludes with a discussion of the development direction and future prospects for high-efficiency SCR catalysts in different industrial fields.

Decentralized Platoon Join-in-Middle Protocol Considering Communication Delay for Connected and Automated Vehicle.

Cooperative driving is an essential component of intelligent transport systems (ITSs). It promises greater safety, reduced accidents, efficient traffic flow, and fuel consumption reduction. Vehicle platooning is a representative service model for ITS. The principal sub-systems of platooning systems for connected and automated vehicles (CAVs) are cooperative adaptive cruise control (CACC) systems and platoon management systems. Based on vehicle state information received through vehicle-to-vehicle (V2V) communication, the CACC system allows platoon vehicles to maintain a narrower safety distance. In addition, the platoon management system using V2V communications allows vehicles to perform platoon maneuvers reliably and accurately. In this paper, we propose a CACC system with a variable time headway and a decentralized platoon join-in-middle maneuver protocol with a trajectory planning system considering the V2V communication delay for CAVs. The platoon join-in-middle maneuver is a challenging research subject as the research must consider the requirement of a more precise management protocol and lateral control for platoon safety and string stability. These CACC systems and protocols are implemented on a simulator for a connected and automated vehicle system, PreScan, and we validated our approach using a realistic control system and V2V communication system provided by PreScan.

Extremely Low-Profile Monopolar Microstrip Antenna with Wide Bandwidth.

In this paper, we propose a new monopolar microstrip antenna for a high-speed moving swarm sensor network. The proposed antenna shows an extremely thin substrate thickness supported with an omni-directional radiation pattern and wide operation frequency bandwidth. First, to achieve the low-profile monopolar microstrip antenna, the symmetrical center feeding network and the gap-coupled six arrayed patches which form a hexagonal microstrip radiator were utilized. The partially loaded ground-slots under the top patches were employed to improve the radiation performance and adjust the impedance bandwidth. Second, to obtain the broad bandwidth of the low-profile monopolar microstrip antenna, the degenerated non-fundamental TM02 modes, that is, even and odd TM02 modes, were carefully analyzed. To verify the feasibility of the degenerated TM02 mode operation, the parametric study of the proposed antenna was theoretically investigated and implemented with the optimized parameter dimensions. Finally, the fabricated antenna showed a 0.254 mm-thick substrate and demonstrates 1.5-wavelength resonant monopolar radiation with broad impedance bandwidth of 855 MHz and its factional bandwidth of 15.24% at the resonant frequency of 5.57 GHz.

Design of a Cooperative Lane Change Protocol for a Connected and Automated Vehicle Based on an Estimation of the Communication Delay.

Connected and automated vehicles (CAVs) have recently attracted a great deal of attention. Various studies have been conducted to improve vehicle and traffic safety through vehicle to vehicle (V2V) communication. In the field of CAVs, lane change research is considered a very challenging subject. This paper presents a cooperative lane change protocol, considering the impact of V2V communication delay. When creating a path for a lane change in the local path planning module, V2V communication delay occurs. Each vehicle was represented, in our study, by an oriented bounding box (OBB) to determine the risk of collision. We set up a highway driving simulation environment and verified the improved protocol by implementing a longitudinal and lateral controller.

Influence of Surface Charges/Chemistry on the Catalysis of Perovskite Complexes.

The electrochemical performance of the perovskite complex was discovered to depend greatly on the different locations of the identical particle, which represent different surface charges accordingly. The surface charges were evaluated by Zeta potential (ζ) for the intrinsic BSCF5582 (Ba0.5Sr0.5Co0.8Fe0.2O3 -δ), ball-milled (BM-BSCF5582), and heat-treated in an oxygen atmosphere after ball-milling (48h-O2-BM-BSCF5582), the mean ζ of which represents -11.1, 21.2, and -6.1 mV, respectively, which reflects well on different surface chemistries. When the bonding structures at the different stratified layers and the overall crystalline morphologies were analyzed via X-ray photoelectron spectroscopy and high resolution transmission electron microscopy, respectively, the crystalline- and bonding-structure at the 50 nm depth of BSCF5582 is nearly identical to that of BM-BSCF5582 at the surface. As ball-milling proceeds, not only are particles comminuted but also the amorphous surface is broken open, leading to the revelation of inner and naïve cubic crystalline phase surfaces and affecting the catalytic activities of oxygen evolution reactions and oxygen reduction reactions positively and negatively, respectively, at significant scales.

Progressive Assessment on the Decomposition Reaction of Na Superionic Conducting Ceramics.

The successful analysis on the microstructure of Hong-type Na superionic conducting (NASICON) ceramics revealed that it consists of several heterogeneous phases: NASICON grains with rectangular shapes, monoclinic round ZrO2 particles, grain boundaries, a SiO2-rich vitrified phase, Na-rich amorphous particles, and pores. A dramatic microstructural evolution of NASICON ceramics was demonstrated via an in situ analysis, which showed that NASICON grains sequentially lost their original morphology and were transformed into comminuted particles (as indicated by the immersion of bulk NASICON samples into seawater at a temperature of 80 °C). The consecutive X-ray diffraction analysis represented that the significant shear stress inside NASICON ceramics caused their structural decomposition, during which H3O+ ions occupied ceramic Na+ sites (predominantly along the (1̅11) and (1̅33) planes), while the original Na+ cations came out in the (020) plane of the NASICON ceramic crystalline structure. The results of time-of-flight secondary-ion mass spectrometry analysis confirmed that large concentrations of Cl- and Na+ ions were distributed across the surface of NASICON ceramics, leading to local densification of a 20 µm thick surface layer after treatment within seawater solution at a temperature of 80 °C.

Fabrication of Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) catalysts with enhanced electrochemical performance by removing an inherent heterogeneous surface film layer.

A heat-treatment approach for Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) (BSCF5582) is introduced as a way of enhancing the electrocatalytic performance of perovskite catalysts. The perovskite made by heat-treatment in oxygen atmosphere loses around 30 nm of spinel layer on the surface relative to the untreated version, and demonstrates enhanced oxygen reduction reaction and oxygen evolution reaction catalytic activities.

A bifunctional perovskite catalyst for oxygen reduction and evolution.

La0.3(Ba0.5Sr0.5)0.7Co0.8Fe0.2O3d is a promising bifunctional perovskite catalyst for the oxygen reduction reaction and the oxygen evolution reaction. This catalyst has circa 10 nm-scale rhombohedral LaCoO3 cobaltite particles distributed on the surface. The dynamic microstructure phenomena are attributed to the charge imbalance from the replacement of A-site cations with La3+ and local stress on Cosite sub-lattice with the cubic perovskite structure.

Short rare hTERT-VNTR2-2nd alleles are associated with prostate cancer susceptibility and influence gene expression.

BACKGROUND: The hTERT (human telomerase reverse transcriptase) gene contains five variable number tandem repeats (VNTR) and previous studies have described polymorphisms for hTERT-VNTR2-2nd. We investigated how allelic variation in hTERT-VNTR2-2nd may affect susceptibility to prostate cancer. METHODS: A case-control study was performed using DNA from 421 cancer-free male controls and 329 patients with prostate cancer. In addition, to determine whether the VNTR polymorphisms have a functional consequence, we examined the transcriptional levels of a reporter gene linked to these VNTRs and driven by the hTERT promoter in cell lines. RESULTS: Three new rare alleles were detected from this study, two of which were identified only in cancer subjects. A statistically significant association between rare hTERT-VNTR2-2nd alleles and risk of prostate cancer was observed [OR, 5.17; 95% confidence interval (CI), 1.09-24.43; P = 0.021]. Furthermore, the results indicated that these VNTRs inserted in the enhancer region could influence the expression of hTERT in prostate cancer cell lines. CONCLUSIONS: This is the first study to report that rare hTERT VNTRs are associated with prostate cancer predisposition and that the VNTRs can induce enhanced levels of hTERT promoter activity in prostate cancer cell lines. Thus, the hTERT-VNTR2-2nd locus may function as a modifier of prostate cancer risk by affecting gene expression.