Low-temperature methanation of fermentation gas with Ni-based catalysts in a multicomponent system.

A large amount of greenhouse gases, such as carbon dioxide and methane, are released during the production process of bioethanol and biogas. Converting CO2 into methane is a promising way of capturing CO2 and generating high-value gas. At present, CO2 methanation technology is still in the early stage. It requires high temperature (300-400 â„ƒ) and pressure (> 1 MPa), leading to high cost and energy consumption. In this study, a new catalyst, Ni-Fe/Al-Ti, was developed. Compared with the activity of the common Ni/Al2O3 catalyst, that of the new catalyst was increased by 1/3, and its activation temperature was reduced by 100℃. The selectivity of methane was increased to 99%. In the experiment using simulated fermentation gas, the catalyst showed good catalytic activity and durability at a low temperature and atmospheric pressure. Based on the characterization of catalysts and the study of reaction mechanisms, this article innovatively proposed a Ni-Fe/Al-Ti quaternary catalytic system. Catalytic process was realized through the synergism of Al-Ti composite support and Ni-Fe promotion. The oxygen vacancies on the surface of the composite carrier and the higher activity metals and alloys promoted by Fe accelerate the capture and reduction of CO2. Compared with the existing catalysts, the new Ni-Fe/Al-Ti catalyst can significantly improve the methanation efficiency and has great practical application potential.

[Effect of Biogas Slurry Return to Field on Heavy Metal Accumulation in Soil-crop System: A Meta-analysis].

To investigate the effects of biogas slurry return-to-field methods, the duration of biogas slurry return to field and the amount of heavy metals brought in from biogas slurry on the accumulation of heavy metals in soil-crop systems, and the importance of factors influencing heavy metal accumulation, 41 papers and 1972 pairs of data were integrated and analyzed. The results showed that the application of biogas slurry alone significantly increased the accumulation of As, Cd, Cr, Cu, and Zn in soil and As and Cr in crops by 20.5%, 15.2%, 25.6%, 18.7%, and 26.3% and 14.6% and 39.5%, respectively, and it had no significant effect on the accumulation of other heavy metals in crops. The combined application of biogas slurry and chemical fertilizers significantly increased the accumulation of soil Cr and Zn by 8.05% and 4.70% and decreased the accumulation of As by crops. Correlation analysis showed that the accumulation rates of soil As, Cd, and Cr were highly significantly and positively correlated (P<0.01) with the duration of biogas slurry return to field and soil organic matter (SOM) content, with correlation coefficients of 0.30, 0.15, and 0.13 and 0.22, 0.27, and 0.22, respectively; they were highly significantly and negatively correlated (P<0.01) with soil pH, with correlation coefficients of 0.16, 0.13, and 0.11, respectively. The heavy metals brought in by biogas slurry return to field promoted the accumulation of As, Cd, and Cr in soil and As, Cd, Cr, and Zn in crops, whereas the accumulation of Cd, Cu, and Zn in soil promoted the accumulation of Cd, Cu, and Zn in crops, with correlation coefficients of 0.45, 0.58, and 0.42, respectively. The main factors of heavy metal accumulation in the soil-crop systems were the duration of biogas slurry return to field, SOM, and soil pH.

Elasto-Plastic Fracture Mechanics Analysis of the Effect of Shot Peening on 300M Steel.

A modified J-integral calculation method is adopted to fix the problem of the quantitative evaluation of the crack propagation of shot-peened structures. Considering the residual stress, residual strain, and residual strain energy, the effect of shot peening on the J-integral parameters of semi-elliptic surface crack fronts is quantitatively calculated and a method is provided for the performance evaluation of the shot peening layer. First, the shot peening process is simulated, then the fatigue crack is generated by changing the constraint condition and a far-field load is applied to calculate the J-integral parameters, crack propagation rate, and crack kinking angle. The effects of different crack depths and shot velocities on the fracture parameters are analyzed. The results show that the reduction in the J-integral value after shot peening decreases with the increase in the crack depth when the shot velocity is a certain value, which indicates that shot peening is more beneficial for suppressing the fatigue crack propagation. When the crack depth is greater than the depth of the compressive stress layer, shot peening accelerates the crack propagation. The reduction in the J-integral value decreases with the increase in shot velocity when the crack depth is a certain value; therefore, increasing shot velocity is more beneficial for retarding fatigue crack propagation.

Six-directional pseudorandom consecutive unicursal polishing path for suppressing mid-spatial frequency error and realizing consecutive uniform coverage.

Planning the polishing path is an important part of the polishing process. Reasonable selection of the polishing path can improve surface quality and reduce the mid-spatial frequency (MSF) error. In this paper, a six-directional pseudorandom consecutive unicursal polishing path and the corresponding generation method are proposed. The proposed path is especially useful for suppressing the MSF error of the surface and realizing consecutive uniform coverage. Compared with traditional polishing paths such as scanning, spiral, and fractal, the proposed path has the following characteristics: multi-directionality, high randomness, smoothness, and consecutiveness. In order to verify that the proposed path has the ability to suppress the MSF error, a group of contrast experiments were conducted and the measurement data was processed by the empirical mode decomposition (EMD) method and the fast Fourier transform (FFT) method. The results show that the fluctuation amplitude of the MSF error and the fluctuation area with MSF error are obviously reduced by using the proposed path. Moreover, the corresponding wavelength of the crests in the spectrum shows multi-values. The experimental results show that the proposed path has high randomness and the ability to suppress the MSF error.

Phytochemical composition and antinociceptive activity of Bauhinia glauca subsp. hupehana in rats.

In traditional medicine, Bauhinia glauca subsp. hupehana has long been used as an analgesic agent in China. The aim of this study was to evaluate the antinociceptive activity of the ethanol extract of the aerial parts of B. glauca subsp. hupehana (BHE) in rats and its chemical fingerprint. The antinociceptive activity of BHE was assessed in mice using chemically and heat-induced pain models, such as the acetic acid-induced writhing, hot plate, tail-flick and glutamate tests. Naltrexone hydrochloride, a non-selective opioid receptor antagonist, was utilized to determine the involvement of the opioid system. In addition to this, the involvements of the cGMP and ATP-sensitive K+ channel pathways were also detected using methylene blue and glibenclamide. The oral administration of BHE (at doses of 50, 100 and 200 mg/kg) produced significant and dose-related inhibitions in both the chemically and heat-induced pain models. Interestingly, in the abdominal constriction test, when the dose of BHE was increased to 800 mg/kg (p.o., n = 10), the inhibition rate was 100%. The antinociceptive mechanism may involve the cGMP pathway and ATP sensitive K+ channel pathway. The central antinociceptive effect was not antagonized by naltrexone. One phenolic acid, one lignin and five flavonoids were isolated from BHE. The antinociceptive activity of BHE was most likely due to the presence of the flavonoids. The acute toxicity results showed that BHE was safe at a high dose (2 g/kg, p.o.). The current investigation demonstrates that B. glauca subsp. hupehana is a potential candidate for the development of novel, non-opioid, analgesic phytomedicines.

Antinociceptive and free radical scavenging activities of alkaloids isolated from Lindera angustifolia Chen.

Lindera angustifolia Chen is a folk medicine used for the treatment of contusions-induced swelling, rheumatic pains and bellyache in south and the middle part of China. Phytochemical studies showed that aporphine and benzyltetrahydroisoquinoline alkaloids are the characteristic constituents of this plant. In this study, we evaluated the antinociceptive and free radical scavenging properties of six aporphine and two benzyltetrahydroisoquinoline alkaloids isolated from the root of Lindera angustifolia. All alkaloids except magnocurarine exhibited remarkable radical scavenging effects (36-90% scavenging at 25-100microg/ml) in DPPH radical scavenging test, among them norisocorydine showed the hightest activity (SC(50): 14.1microg/ml). Antinociceptive activities were tested by using acetic acid-induced writhing and formalin test at dose of 20mg/kg. Norisocorydine exhibited the highest antinociceptive ability with 83.5% writhing inhibition. Boldine, norboldine showed significant antinociceptive activity with 76.3% and 74.6% writhing inhibition respectively. Indomethacin was used as positive control, which showed 67.8% writhing inhibition at dose of 10mg/kg. Most of the compounds, except N-ethoxycarbonyllaurotetanine and magnocurarine, could significantly inhibit the phase I reaction (P<0.01), and all of them inhibited the phase II reaction (P<0.001) in the formalin tests (indomethacin and morphine were used as positive drugs). The antinociceptive effects exhibited a structure-activity relationship similar to that of the free radical scavenging activities. Above results suggested that the alkaloids from the root of Lindera angustifolia possess both free radical scavenging and antinociceptive activities, and the antinociceptive activity seems to be related to the free radical scavenging effect.

[Alkaloids from the root of Lindera angustifolia].

AIM: To study the alkaloid constituents of the root of Lindera angustifolia Cheng. METHODS: The constituents were isolated and purified by column chromatography and the structures were characterized by spectral analysis. RESULTS: Seven aporphine alkaloids, laurotetanine (I), N-methyllaurotetanine (II), boldine (III), isoboldine (IV), norboldine (V), N-ethoxycarbonyllaurotetanine (VII) and a quaternary isoquinoline alkaloid, magnocurarine (VI), were isolated and identified. The structure of VII was further identified by semi-synthesis with I as starting material. CONCLUSION: All compounds were obtained from this plant for the first time and compound VII was found as a naturally occurring compound for the first time.