Influence of CaCO3 on Density and Compressive Strength of Calcium Aluminate Cement-Based Cementitious Materials in Binder Jetting.

We investigated the impact of CaCO3 addition on the density and compressive strength of calcium aluminate cement (CAC)-based cementitious materials in binder jetting additive manufacturing (BJAM). To confirm the formation of a uniform powder bed, we examined the powder flowability and powder bed density for CaCO3 contents ranging from 0 to 20 wt.%. Specifically, powders with avalanche angles between 40.1-45.6° formed a uniform powder bed density with a standard deviation within 1%. Thus, a 3D printing specimen (green body) fabricated via BJAM exhibited dimensional accuracy of less than 1% across the entire plane. Additionally, we measured the hydration characteristics of CAC and the changes in compressive strength over 30 days with the addition of CaCO3. The results indicate that the addition of CaCO3 to CAC-based cementitious materials forms multimodal powders that enhance the density of both the powder bed and the green body. Furthermore, CaCO3 promotes the formation of highly crystalline monocarbonate (C4AcH11) and stable hydrate (C3AH6), effectively inhibiting the conversion of CAC and showing compressive strengths of up to 5.2 MPa. These findings suggest a strong potential for expanding the use of BJAM across various applications, including complex casting molds, cores, catalyst supports, and functional architectural interiors.

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.

High-Dispersed V2O5-CuOX Nanoparticles on h-BN in NH3-SCR and NH3-SCO Performance.

Typically, to meet emission regulations, the selective catalytic reduction of NOX with NH3 (NH3-SCR) technology cause NH3 emissions owing to high NH3/NOX ratios to meet emission regulations. In this study, V-Cu/BN-Ti was used to remove residual NOX and NH3. Catalysts were evaluated for selective catalytic oxidation of NH3 (NH3-SCO) in the NH3-SCR reaction at 200-300 °C. The addition of vanadium and copper increased the number of Brønsted and Lewis acid sites available for the reaction by increasing the ratio of V5+ and forming Cu+ species, respectively. Furthermore, h-BN was dispersed in the catalyst to improve the content of vanadium and copper species on the surface. NH3 and NOX conversion were 98% and 91% at 260 °C, respectively. Consequently, slipped NH3 (NH3-Slip) emitted only 2% of the injected ammonia. Under SO2 conditions, based on the NH3 oxidation reaction, catalytic deactivation was improved by addition of h-BN. This study suggests that h-BN is a potential catalyst that can help remove residual NOX and meet NH3 emission regulations when placed at the bottom of the SCR catalyst layer in coal-fired power plants.

Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia.

In this study, we synthesized V2O5-WO3/TiO2 catalysts with different crystallinities via one-sided and isotropic heating methods. We then investigated the effects of the catalysts' crystallinity on their acidity, surface species, and catalytic performance through various analysis techniques and a fixed-bed reactor experiment. The isotropic heating method produced crystalline V2O5 and WO3, increasing the availability of both Brønsted and Lewis acid sites, while the one-sided method produced amorphous V2O5 and WO3. The crystalline structure of the two species significantly enhanced NO2 formation, causing more rapid selective catalytic reduction (SCR) reactions and greater catalyst reducibility for NOX decomposition. This improved NOX removal efficiency and N2 selectivity for a wider temperature range of 200 °C-450 °C. Additionally, the synthesized, crystalline catalysts exhibited good resistance to SO2, which is common in industrial flue gases. Through the results reported herein, this study may contribute to future studies on SCR catalysts and other catalyst systems.

Synthesis of oxygen functionalized carbon nanotubes and their application for selective catalytic reduction of NO x with NH3.

Oxygen functionalized carbon nanotubes synthesized by surface acid treatment were used to improve the dispersion properties of active materials for catalysis. Carbon nanotubes have gained attention as a support for active materials due to their high specific surface areas (400-700 m2 g-1) and chemical stability. However, the lack of surface functionality causes poor dispersion of active materials on carbon nanotube supports. In this study, oxygen functional groups were prepared on the surface of carbon nanotubes as anchoring sites for decoration with catalytic nanoparticles. The oxygen functional groups were prepared through a chemical acid treatment using sulfuric acid and nitric acid, and the amount of functional groups was controlled by the reaction time. Vanadium, tungsten, and titanium oxides as catalytic materials were dispersed using an impregnation method on the synthesized carbon nanotube surfaces. Due to the high density of oxygen functional groups, the catalytic nanoparticles were well dispersed and reduced in size on the surface of the carbon nanotube supports. The selective catalytic reduction catalyst with the oxygen functionalized carbon nanotube support exhibited enhanced NO x removal efficiency of over 90% at 350-380 °C which is the general operating temperature range of catalysis in power plants.

Enhanced NOx removal efficiency for SCR catalyst of well-dispersed Mn-Ce nanoparticles on hexagonal boron nitride.

This research is conducted to improve the dispersion of MnOx-CeO2 catalyst because manganese is easily aggregated during continuous thermal environment at operating temperature. Aggregated MnOx particles on the support can be a major reason to degrade the catalyst performance. Therefore, the improved dispersion of MnOx particles leads to the enhancement of the catalyst performance by utilizing hexagonal boron nitride (h-BN) which is well known as thermally stable material. Due to the dispersion of MnOx-CeO2 with 5-20 nm particle size, h-BN-supported MnOx-CeO2 catalyst shows the 93% efficiency in NOx removal at 200 °C. The structure and properties of MnOx-CeO2/h-BN catalyst are characterized by X-ray diffraction, Fourier transform infrared spectroscopy spectra, and NH3-temperature programmed desorption. Then, NOx removal efficiency of catalyst is evaluated on a fixed bed reactor and h-BN-supported catalyst, (Mn0.2-Ce0.1)/BN, increases NOx removal efficiency up to 20% at 200 °C in spite of 2/3 reduced content of MnOx-CeO2 compared to no-supported catalyst (Mn0.3-Ce0.15).

Noninvasive and repetitive measurement of cellular metabolite from human osteosarcoma cells (MG-63) using 3.0 tesla proton (1 H) MR spectroscopy.

PURPOSE: This study suggests a noninvasive and repetitive measurement method using 1 H magnetic resonance spectroscopy to monitor changes in cellular metabolites within a single sample. METHODS: Longitudinal acquisition of cellular metabolites from three-dimensional cultured human osteosarcoma (MG-63) cells was conducted using 3.0 Tesla 1 H MRS for 2 weeks at three time points: days 1, 7, and 14. During the MR spectroscopy (MRS) scan, cell specimen temperatures were kept constant at 37°C by a lab-developed magnetic resonance compatible thermostatic device. A DNA assay and live/dead staining of the cell specimens were carried out at each time point to verify the MRS measurements. RESULTS: Cell viability in the proposed device did not significantly differ from that of cells in a conventional incubator (P = 0.946). Cell proliferation and choline concentration increased during the first week, but remained constant during the second week. Lactate did not change during the first week, but increased during the second week. Likewise, cell viability remained constant until day 7, then decreased. CONCLUSION: The proposed MRS technique results in a survivable environment for longitudinal studies of cells and provides a new way to measure metabolomic changes over time in single specimens of cells. Magn Reson Med 76:1912-1918, 2016. © 2016 International Society for Magnetic Resonance in Medicine.

Synthesis of Vanadium Oxide Supported on Reduced Graphene Oxide for De-Nox.

Graphene has many excellent properties such as wide specific surface area, outstanding electrical mobility, and high optical transmittance. Due to these advantages, which make graphene appropriate matrix supporting vanadium for the nanocomposite. Also, depending on the synthesis process, graphene can be obtainable graphene oxide (GO) and reduced graphene oxide (RGO). Moreover, RGO has been receiving increased attention due to its nature to easily reduced to graphene, referred to as RGO, which has wide application. The purpose of this study is to investigate the characteristic of V2O5 deposited on RGO. The nanocomposite of vanadium oxide (V2O5) supported on RGO was prepared by different methods of evaporation, impregnation and impregnation with dispersant. XRD, SEM, TEM, BET and TGA analyses were used to investigate their chemical stability, and amount in vanadium oxide on RGO. This synthesis of V2O5 supported RGO is expected to be used as selective catalytic reduction (SCR) catalyst for De-NOx.

A case of ruptured renal cortical arteriovenous malformation of the right testicular vein in hemorrhagic fever with renal syndrome.

Hemorrhagic fever with renal syndrome (HFRS) is an acute viral disease characterized by fever, hemorrhage, and renal failure. Among the various hemorrhagic complications of HFRS, the spontaneous rupture of an arteriovenous malformation of the testicular vessels with a retroperitoneal hematoma is a rare finding. Here, we report a case of HFRS complicated by a massive retroperitoneal hematoma that was treated with transcatheter arterial embolization.

Portal vein occlusion after biliary metal stent placement in hilar cholangiocarcinoma.

Acute symptomatic portal vein obstruction related to biliary stenting is an extremely rare but life-threatening complication. This usually occurs in patients with either tumor invasion into the portal vein or pre-existing portal vein thrombus. Therefore, the portal vein should be carefully evaluated before placing a biliary metallic stent in such patients. We describe a case of acute portal vein obstruction after placing metallic biliary stents in a patient with a periductal-infiltrating type of hilar cholangiocarcinoma.

Imaging findings of primary well-differentiated liposarcoma of the liver: a case report.

Primary liposarcoma of the liver is extremely rare. We report here on a case of primary well-differentiated liposarcoma in the left hepatic lobe of a 63-year-old woman. Abdominal ultrasonography showed a well-defined, echogenic, round mass. Abdominal computed tomography (CT) and magnetic resonance (MR) images showed an almost fatty, lobulated mass with a few, random distributed vascular structures and a small area of nodular enhancement. The resected tumor appeared as a well-defined, round, tan-yellow mass. Histological analysis showed a well-differentiated liposarcoma.

Inflammatory breast cancer: imaging findings.

To assess the imaging findings of inflammatory breast cancer, we retrospectively analyzed the mammography, ultrasonography, and magnetic resonance imaging (MRI) findings of nine patients with inflammatory breast cancer. Inflammatory breast cancer showed skin thickening and nipple-areolar swelling on mammography, ultrasonography, and MRI. Tumor with lymphatic dilatation on ultrasonography and enhancement of thickened skin and parenchyma on MRI can be useful findings in the diagnosis of inflammatory breast cancer.