Strength Prediction of Ball-Milling-Modified Phosphorus Building Gypsum Based on NSGM (1,4) Model

Phosphogypsum is an industrial byproduct from the wet preparation of phosphoric acid. Phosphorus building gypsum can be obtained from phosphogypsum after high-thermal dehydration. This study aimed to analyze the influence of ball milling with different parameters on the strength of phosphorus building gypsum. In this paper, the absolute dry flexural strength and the absolute dry compressive strength of phosphorus building gypsum were compared under different mass ratios of material to ball, ball-milling speed, and ball-milling time, and the NSGM (1,4) model was applied to model and predict the strength of phosphorus building gypsum modified by ball milling. According to the research results, under the same mass ratio of material to ball and ball-milling speed, the absolute dry flexural strength and absolute dry compressive strength of phosphorus building gypsum firstly increased and then decreased with the increase in milling time. The NSGM (1,4) model established in this paper could effectively simulate and predict the absolute dry flexural strength and the absolute dry compressive strength of the ball-milling-modified phosphorus building gypsum; the average relative simulation errors were 12.38% and 13.77%, and the average relative prediction errors were 6.30% and 12.47%

A Two-Dimensional Cloud Model for Condition Assessment of HVDC Converter Transformers

Converter transformers are the key and the most important components in high voltage direct current (HVDC) power transmission systems. Statistics show that the failure rate of HVDC converter transformers is approximately twice of that of transformers in AC power systems. This paper presents an approach integrated with a two-dimensional cloud model and an entropy-based weight model to evaluate the condition of HVDC converter transformers. The integrated approach can describe the complexity of HVDC converter transformers and achieve an effective assessment of their condition. Data from electrical testing, DGA, oil testing, and visual inspection were chosen to form the double-level assessment index system. Analysis results show that the integrated approach is capable of providing a relevant and effective assessment which in turn, provides valuable information for the maintenance of HVDC converter transformers

Development of artificial shape-setting energy storage phosphorous building gypsum aggregate

The research and development of new building materials such as phosphorous building gypsum is crucial to promote the utilisation of phosphogypsum resources by improving their value. This study developed a new type of shape-stabilised energy storage phosphorus building gypsum aggregate (ES-PBGA). The mechanical and thermal properties of ES-PBGA with Paraffin were investigated. The results indicate that the matrix of ES-PBGA had a good microstructure, and the optimal paraffin-embedding rate of ES-PBGA was 31.08%. The phase transition temperature and enthalpy of the endothermic and exothermic stages were 17.6 and 27.14 ℃, and 33.02 and 31.62 J/g, respectively. The cylinder pressure strength of ES-PBGA with paraffin (31.08%) was 4.32 MPa, which meets the requirements of artificial aggregate application. To verify the practicability of ES-PBGA, energy storage lightweight aggregate concrete was prepared with 0%, 25%, 50%, and 100% ES-PBGA to replace the lightweight shale ceramsite. The results show that ES-PBGA can improve the interface transition zone between cement-based materials and energy storage aggregates, thereby improving the strength, and has a relatively suitable thermal conductivity, thermal diffusion coefficient, and specific heat capacity. Furthermore, it is also a type of low-carbon energy storage aggregate, and its application in the field of energy storage composite building materials is a relatively new concept

Preparation and Pore Structure of Energy-Storage Phosphorus Building Gypsum

In this study, the pore structure of a hardened phosphorous building gypsum body was optimised by blending an air-entraining agent with the appropriate water–paste ratio. The response surface test was designed according to the test results of the hardened phosphorous building gypsum body treated with an air-entraining agent and an appropriate water–paste ratio. Moreover, the optimal process parameters were selected to prepare a porous phosphorous building gypsum skeleton, which was used as a paraffin carrier to prepare energy-storage phosphorous building gypsum. The results indicate that if the ratio of the air-entraining agent to the water–paste ratio is reasonable, the hardened body of phosphorous building gypsum can form a better pore structure. With the influx of paraffin, its accumulated pore volume and specific surface area decrease, and the pore size distribution is uniform. The paraffin completely occupies the pores, causing the compressive strength of energy-storage phosphorous building gypsum to be better than that of similar gypsum energy-storing materials. The heat energy further captured by energy-storage phosphorous building gypsum in the endothermic and exothermic stages is 28.19 J/g and 28.64 J/g, respectively, which can be used to prepare energy-saving building materials

A study on the correlation of placental anastomosis and superficial vascular branches of selective fetal growth restriction in monochorionic diamniotic twins

Abstract Introduction The main purpose of the present study was to investigate the correlation between placental anastomosis and superficial vascular branches in selective fetal growth restriction (sFGR) in monochorionic diamniotic twins. Materials and methods This was a retrospective analysis of the pregnancy data and placental perfusion of 395 patients with monochorionic diamniotic (MCDA) twin pregnancies delivered at our hospital from April 2013 to April 2020. We divided the patients into two groups and compared the number of placental superficial vascular branches in sFGR twins and normal MCDA twins. The correlation between the placental anastomosis and the number of superficial vascular branches in sFGR and normal MCDA twins was also investigated. Results The number of umbilical arterial branches and umbilical venous branches was less than larger twins in sFGR, larger twins in normal MCDA and smaller twins in normal MCDA. (11.83 [4–44], 21.82 [7–50], 19.72 [3–38], 14.85 [0–31], p < 0.001, 6.08 [1–18], 9.60 [3–22], 9.96 [2–22], 8.38 [1–20], p < 0.00) For smaller twins in the sFGR group, the number of umbilical venous branches was positively associated with AA anastomosis overall diameter, AV anastomosis overall diameter and all anastomosis overall diameter. (r = 0.194, 0.182 and 0.211, p < 0.05) Conclusions The risk of sFGR may arise when the placenta from MCDA twins shows a poor branching condition of placental superficial vessels. For the smaller twin of sFGR, regular ultrasound examination of the number of the umbilical venous branches may help to predict artery-to-artery (AA) overall diameter, artery‐to‐vein (AV) overall diameter and all anastomosis overall diameter

Schisandrin B Attenuates Hepatic Stellate Cell Activation and Promotes Apoptosis to Protect against Liver Fibrosis

The activation of hepatic stellate cells (HSC) plays a key role in the progression of hepatic fibrosis, it is essential to remove activated HSC through apoptosis to reverse hepatic fibrosis. Schisandrin B (Sch B) is the main chemical component of schisandrin lignan, and it has been reported to have good hepatoprotective effects. However, Schisandrin B on HSC apoptosis remains unclear. In our study, we stimulated the HSC-T6 and LX-2 cell lines with TGF-β1 to induce cell activation, and the proliferation and apoptosis of the activated HSC-T6 and LX-2 cells were detected after treatment with different doses of Schisandrin B. Flow cytometry results showed that Sch B significantly reduced the activity of activated HSC-T6 and LX-2 cells and significantly induced apoptosis. In addition, the cleaved-Caspase-3 levels were increased, the Bax activity was increased, and the Bcl-2 expression was decreased in HSC-T6 and LX-2 cells treated with Sch B. Our study showed that Sch B inhibited the TGF-β1-induced activity of hepatic stellate cells by promoting apoptosis

Effects of particle shaping on the performance of phosphorus building gypsum

Phosphogypsum (PG) is an industrial by-product from the wet preparation of phosphoric acid. Phosphorus building gypsum (PBG) can be obtained from PG after high-thermal dehydration. Improving the properties of PBG is of great significance to extending its application range. In this paper, PBG was modified by particle shaping, resultantly its properties have been significantly improved. This study utilized a small-scale ball mill as a power source for simulated shaping to investigate the shape parameters of PBG particles before and after shaping. Further, the effects of different material-to-ball mass ratios, ball milling speeds, and shaping durations on PBG performance were examined. Shaped PBG particles exhibited a reduction in aspect ratio, approaching a roundness of approximately 1. The sharp edges on the particle surfaces decreased, resulting in a particle appearance that tended to approach a spherical form. Moreover, when the material-to-ball mass ratio and ball milling speed were held constant, increasing the shaping duration decreased and then increased the water amount required for normal consistency and setting time of PBG. However, the strength, first increased and then decreased. Under the conditions of a material-to-ball mass ratio of 1:1, ball milling speed of 90 r/min, and a shaping duration of 5 min, PBG exhibited the most significant enhancement in mechanical properties. Finally, the mechanism of how particle shaping affects PBG performance was analyzed using the theory of water film thickness

Long-Term Maize Intercropping with Peanut and Phosphorus Application Maintains Sustainable Farmland Productivity by Improving Soil Aggregate Stability and P Availability

The intercropping of maize (Zea mays L.) and peanuts (Arachis hypogaea L.) (M||P) significantly enhances crop yield. In a long-term M||P field experiment with two P fertilizer levels, we examined how long-term M||P affects topsoil aggregate fractions and stability, organic carbon (SOC), available phosphorus (AP), and total phosphorus (TP) in each aggregate fraction, along with crop yields. Compared to their respective monocultures, long-term M||P substantially increased the proportion of topsoil mechanical macroaggregates (7.6–16.3%) and water-stable macroaggregates (>1 mm) (13.8–36.1%), while reducing the unstable aggregate index (ELT) and the percentage of aggregation destruction (PAD). M||P significantly boosted the concentration (12.9–39.9%) and contribution rate (4.1–47.9%) of SOC in macroaggregates compared to single crops. Moreover, the concentration of TP in macroaggregates (>1 mm) and AP in each aggregate fraction of M||P exceeded that of the respective single crops (p 2-P, Ca8-P, Al-P, and Fe-P concentrations of intercropped maize (IM) and the Ca8-P, O-P, and Ca10-P concentrations of intercropped peanuts (IP). The land equivalent ratio (LER) of M||P was higher than one, and M||P stubble improved the yield of subsequent winter wheat (Triticum aestivum L.) compared with sole-crop maize stubble. P application augmented the concentration of SOC, TP, and AP in macroaggregates, resulting in improved crop yields. In conclusion, our findings suggest that long-term M||P combined with P application sustains farmland productivity in the North China Plain by increasing SOC and macroaggregate fractions, improving aggregate stability, and enhancing soil P availability