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Forecasting is important for social development and industrial production in today's complex and fluctuating economic environment. The nonlinearity and non-stationarity of financial time series (FTS) data make it difficult to achieve accurate prediction. This work proposes a forecasting method for the return of FTS based on the emerging field of graph signal processing (GSP). The proposed method makes forecasting decisions based on the similarity between the current tendency and historical tendencies of FTS data. First, a topological graph is created based on the underlying structural relationship of different historical FTS datasets. Subsequently, spectral clustering is used to select historical datasets that are similar to the current dataset, and then the future values are predicted by weighted averaging the selected historical samples. In addition, a momentum-driven method is introduced to improve the robustness of the forecasting results. Finally, the proposed method is extended to a collaborative forecasting framework, where auxiliary macroeconomic data is introduced to improve the forecasting accuracy. The superiority of the proposed methods is verified by a set of numerical experiments with different stock indices. [ABSTRACT FROM AUTHOR]

This work aims to study the improvement effect of Sm on Mn-based catalysts for selective catalytic reduction (SCR) of NO with NH3. A series of SmxMn0.3−xTi catalysts (x = 0, 0.1, 0.15, 0.2, and 0.3) were prepared by co-precipitation. Activity tests indicated that the Sm0.15Mn0.15Ti catalyst showed superior performances, with a NO conversion of 100% and N2 selectivity above 87% at 180–300°C. The characterizations showed that Sm doping suppressed the crystallization of TiO2 and Mn2O3 phases and increased the specific surface area and acidity. In particular, the surface area increased from 152.2 m2·g−1 for Mn0.3Ti to 241.7 m2°g−1 for Sm0.15Mn0.15Ti. These effects contributed to the high catalytic activity. The X-ray photoelectron spectroscopy (XPS) results indicated that the relative atomic ratios of Sm3+/Sm and Oβ/O of Sm0.15Mn0.15Ti were 76.77at% and 44.11at%, respectively. The presence of Sm contributed to an increase in surface-absorbed oxygen (Oβ) and a decrease in Mn4+ surface concentration, which improved the catalytic activity. In the results of hydrogen temperature-programmed reduction (H2-TPR), the presence of Sm induced a higher reduction temperature and lower H2 consumption (0.3 mmol·g−1) for the Sm0.15Mn0.15Ti catalyst compared to the Mn0.3Ti catalyst. The decrease in Mn4+ weakened the redox property of the catalysts and increased the N2 selectivity by suppressing N2O formation from NH3 oxidation and the nonselective catalytic reduction reaction. The in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) revealed that NH3-SCR of NO over the Sm0.15Mn0.15Ti catalyst mainly followed the Eley—Rideal mechanism. Sm doping increased surface-absorbed oxygen and weakened the redox property to improve the NO conversion and N2 selectivity of the Sm0.15Mn0.15Ti catalyst. [ABSTRACT FROM AUTHOR]

Red mud is a waste discharged from alumina production by Bayer process. It contains iron and titanium resources. Secondary aluminum dross (SAD) is a waste discharged from aluminum smelting and processing. It contains hazardous reactive aluminum nitride (AlN). In this work, iron and titanium in red mud were reduced by AlN in SAD by pyrometallurgy, and slag was manufactured into glass ceramics. Recovery rates of iron and titanium were 97% and 75%, when addition amount of red mud was double of SAD. The reduced iron and titanium were in form of metal iron and titanium nitride (TiN). Reduction process consisted of two steps: AlN, iron and titanium entered aluminosilicate network of melt; AlN reduced iron and titanium. Density, water absorption and microhardness of the glass ceramics were 3.10 g cm−3, 0.03% and 1195 HV. Utilizing 1 ton of SAD to replace carbon for iron reduction could reduce carbon emissions by 407 kg. In addition, co-disposing 400 kg red mud and 200 kg SAD could gain profit of 293 dollars. This work realized the total recycling of both red mud and SAD. [ABSTRACT FROM AUTHOR]

TiO2 is the dominant and most widely researched photocatalyst for environmental remediation, however, the drawbacks, such as only responding to UV light (<5% of sunlight), low charge separation efficiency, and difficulties in recycling, have severely hindered its practical application. Herein, we synthesized magnetically separable Fe3O4@MoS2@mesoporous TiO2 (FMmT) photocatalysts via a simple, green, and template-free solvothermal method combined with ultrasonic hydrolysis. It is found that FMmT possesses a high specific surface area (55.09 m2·g−1), enhanced visible-light responsiveness (∼521 nm), and remarkable photogenerated charge separation efficiency. In addition, the photocatalytic degradation efficiencies of FMmT for methylene blue (MB), rhodamine B (RhB), and tetracycline (TC) are 99.4%, 98.5%, and 89.3% within 300 min, respectively. The corresponding degradation rates are 4.5, 4.3, and 3.1 times higher than those of pure TiO2 separately. Owing to the high saturation magnetization (43.1 A·m2·kg−1), FMmT can achieve effective recycling with an applied magnetic field. The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS2 and the electron—hole separation caused by the MoS2@TiO2 heterojunction. Meanwhile, the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO2 shell further boost the photocatalytic efficiency of FMmT. This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell. [ABSTRACT FROM AUTHOR]

Industrial solid waste (ISW)—cement blends have the advantages of low carbon, low energy consumption, and low pollution, but their clinker replacement level in low carbon cement is generally low. To address this challenge, this study considers the latest progress and development trends in the ISW—cement blend research, focusing on the activation of ISWs, the formation of ISW—cement blends, and their associated hydration mechanisms. After the mechanical activation of ISWs, the D50 (average size) typically drops below 10 µm, and the specific surface area increases above 350 m2/kg. Thermal activation can increase the glassy-phase content and reactivity of ISWs, where the coal gangue activation temperature is usually set at 400–1000°C. Furthermore, the roles of ISWs in the hydration of ISW—cement blends are divided into physical and chemical roles. The physical action of ISWs usually acts in the early stage of the hydration of ISW—cement blends. Subsequently, ISWs participate in the hydration reaction of ISW—cement blends to generate products, such as C—(A)—S—H gels. Moreover, alkali activation affects the hydration kinetics of ISW—cement blends and modifies the proportion of gels. Environmental impacts and costs of ISW—cement blends have also been discussed to guide stakeholders in selecting sustainable ISWs. [ABSTRACT FROM AUTHOR]

Municipal solid waste incineration products of bottom ash (BA), fly ash (FA), and pickling sludge (PS), causing severe environmental pollution, were transformed into glass ceramic foams with the aid of CaCO3 as a pore-foaming agent during sintering. The effect of the BA/FA mass ratio on the phase composition, pore morphology, pore size distribution, physical properties, and glass structure was investigated, with results showing that with the increase in the BA/FA ratio, the content of the glass phase, Si-O-Si, and Q3Si units decrease gradually. The glass transmission temperature of the mixture was also reduced. When combined, the glass viscosity decreases, causing bubble coalescence and uneven pore distribution. Glass ceramic foams with uniform spherical pores are fabricated. When the content of BA, FA, and PS are 35wt%, 45wt%, and 20wt%, respectively, contributing to high performance glass ceramic foams with a bulk density of 1.76 g/cm3, porosity of 56.01%, and compressive strength exceeding 16.23 MPa. This versatile and low-cost approach provides new insight into synergistically recycling solid wastes. [ABSTRACT FROM AUTHOR]

The effect of Cu, Fe, Co, Ni, Cr and Zn on Mn–Zr–Ti mixed oxides catalysts introduced by co-precipitation was investigated. The Mn–Co catalyst showed the highest NO conversion near 100% and a good N2 selectivity > 90% at 200–300 °C. Comparing with the Mn–non catalyst, the Mn–Co catalyst presented a higher reaction rate constant at 120 °C with 23.3 ml s−1 g−1. The Mn–Co catalyst possesses a high concentration of Mn4+ and surface labile oxygen, which should improve the redox property and increase catalytic activity. Additionally, the Mn–Co showed the highest ratio of Lewis acid sites. The resistance to SO2 was improved by incorporation of Co. In summary, the Mn–Zr–Ti mixed oxides catalyst have a better N2 selectivity than other Mn-based catalysts and could be improved by doping with Co. [ABSTRACT FROM AUTHOR]

Mixed oxide catalysts yMn-Zr-Ti (y/10/10 with y = 1, 3, 5, 7 and 9) for the selective catalytic reduction (SCR) of NOx with NH3 in the presence of oxygen were synthesized by co-precipitation. The catalyst 5Mn-Zr-Ti exhibited a catalytic activity higher than 87% above 160 °C and N2 selectivity above 92% at 100-300 °C. The SCR performance was quite stable at 180 and 200 °C for 15 h. Mn species are shown to improve the catalytic activity by providing more surface labile oxygen, while a synergistic effect among Mn, Zr and Ti species suppressed the generation of N2O. According to in situ DRIFT analysis, NOx was primarily reduced by the reaction of bidentate nitrate and monodentate nitrito species with adsorbed NH3. Subsequently, a comprehensive reaction mechanism was proposed. Accordingly, the formation of NH species was inhibited, and hence, the N2O formation by the reaction of NH and bidentate nitrate was suppressed. Furthermore, the investigation of the deactivation mechanism by SO2 indicated that both the deposition of ammonium sulfates and the sulfation of Mn active sites resulted in the deactivation of the catalyst 5Mn-Zr-Ti. The deposition of ammonium sulfates at 180 °C was more pronounced than that at 220 °C. [ABSTRACT FROM AUTHOR]

This paper presents a classic process-structure-properties approach for optimizing the magnetic properties of electrical steels. Cold-rolled non-oriented electrical steel (Fe; 0.001 wt% C; 0.2 wt.% Mn; 1.3 wt% Si) was subjected to extremely short 3-30 seconds annealing cycles in a range from 880 °C to 980 °C with a heating rate varying from 15 °C to 300 °C/sec. The resulting microstructure was studied by means of optical microscopy and X-ray orientation distribution function analysis. Recrystallized grains were refined with increased heating rate, caused by the nucleation rate increase, which is faster than the growth rate due to rapid heating. The optimal grain size of 60 to 80 mm in terms of magnetic properties was obtained by increasing the annealing temperature range to 920 °C to 940 °C with a higher heating rate of 300 °C/sec and an annealing time of 6 to 9 seconds. With the heating rate increase, the characteristic {111} recrystallization fiber of cold-rolled steel was depressed, but the beneficial {110}〈001〉 Goss texture component was significantly strengthened. The recrystallized grain size and texture were enhanced by rapid annealing, and, as a result, the magnetic properties of non-oriented electrical steel improved. [ABSTRACT FROM AUTHOR]

The rapid heating effects on the microstructure, texture and magnetic properties of 3% Si non-oriented electrical steel has been investigated through optical microscopy, X-ray diffraction and Epstein frame. The results show that recrystallized grains were refined with increased heating rate, caused by the nucleation rate increase, which is faster than the growth rate due to rapid hearting. With the heating rate increase, the characteristic {111} recrystallization fibre of cold-rolled steel was depressed, but the beneficial 〈001〉//RD and 〈001〉//ND fibres were significantly strengthened. Although the grain-size decreases with heating rate increasing, the optimal magnetic properties can also be obtained through the recrystallized grain-size and texture optimization by rapid heating. In this research, we find the magnetic properties optimization can be obtained when annealed with 100°C/s heating rate: the core loss ( P) decrease 13% and the magnetic induction ( B) increase 3%. [ABSTRACT FROM AUTHOR]

Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process, the cracks and the pores on the surface of the powder decreased which in turn decreased the micro-hardness. The Vickers-hardness of the powder decreased from 50-42, while the resistance of the cores increased by 87% after annealing at 400°C for 30 min. The amplitude permeability and magnetic loss of the cores reached the maximum and minimum values, respectively. The magnetic loss of the cores was separated into hysteresis loss and eddy current loss by Stoppels Method which were decreased by the annealing process. [ABSTRACT FROM AUTHOR]

Bonded Terfenol-D composites, with high electrical resistivity and low eddy current loss, can be used in an alternating magnetic field with high frequency. However, the nonmagnetic binder impairs the magnetostriction of the composites. To achieve high magnetostriction and low eddy current loss, the mixture of the alloy powder and binder was compressed at low pressure in an oriented magnetic field. After this, the aligned samples were recompressed by cold isostatic pressing (CIP). Besides, the effect of particle size on the magnetostriction of the bonded Terfenol-D composites was also studied. The results showed that the bonded Terfenol-D composites had excellent magnetostriction when the particle size was 50-80 μm. The oriented magnetic field and CIP could improve the magnetostriction of the bonded composites, which reaches 1020×10. The bonded Terfenol-D composites had good compact structure and high density (7.24 g/cm). The magnetic loss of the bonded Terfenol-D composites was 192 mW/cm at a frequency of 100 kHz in a magnetic field of 960 A/m, which was about one third of that of casting Terfenol-D alloys. [ABSTRACT FROM AUTHOR]

Spherical or nearly regular hexagonal Nd powders with the size of 20–150 nm, Fe powders with the size of 20–150 nm and Mo powders with the size of 80–100 nm were prepared by Argon and Hydrogen arc plasma. The nanostructural NdFe10.5Mo1.5 compound with ThMn12-type structure have been formed after having been mechanically alloyed for 6–12 hours and crystallized at 700–850 °C under high purified Argon atmosphere. After having been nitrided at 400–500 °C for 2 hours, NdFe10.5Mo1.5N x nanopowders with ThMn12-type structure can be obtained, which have excellent permanent magnetic properties such as iH c within range of 360.4–716.2 kA/m (4528–8997 Oe), Br within range of 0.6363–0.9831 T (6363–9831 Gs), ( BH)max within range of 42.87–166.2 kJ/m3 (5.386–20.88 MGOe). [ABSTRACT FROM AUTHOR]