The concentration distribution of combustible dust determines thermal intensity distribution during an explosion. Current measurements for dust concentration have their particular limitations. ...Targeting this, we proposed an “ultrasonic-electric” hybrid detection system and a fusion model. We deployed 12 of the ultrasonic-electric hybrid systems in orthogonal arrays to comprehensively observe the clouds. First, the ultrasonic-electric hybrid detection systems obtained concentration data in real time, and those data were calculated by fusion model. Then, the clouds and their concentrations changing with time were depicted. We analyzed those trends and found certain patterns in them. Our approach can provide a fast, accurate way to detect concentrations of dynamic and complex dust. Finally, the corresponding relationship between the dust concentration distribution and its explosive heat intensity distribution is obtained. The results show that the thermal distribution of combustible dust at a concentration of 20-120 g/m
3
is proportional to the concentration. This is important for preventing dust explosions and reducing the thermal intensity of explosions.
In order to study the temperature transference characteristics of capillary radiant heating ground, a glowing temperature change flooring model is typically established to analyze the influence of ...different factors on the heat transfer characteristics of the heating system. The results show that the distribution of covering temperature is uneven in the radiant heating system, and the fluctuation amplitude increases with the increase of the pipe spacing. At the same time, the change of the surface temperature is further analyzed for the finishing layer material on the radiant heating storey. The results show that the change of the capillary tube spacing leads to a smaller change in the floor exterior temperature when the wood floor is used as the finishing layer. It accurately indicates that the wood floor as the finishing layer can allegedly provide a more balanced surface temperature. Finally, the effects of finishing the layer, filling layer material and pipe spacing are studied for the change of surface heat flux. The results show that the heating effect of 30°C quandary in capillary radiant heating system can merely reach that of 40°C hot water in heating structure with traditional pipe breadth when the finishing layer universally adopts floor tiles and the capillary pipe diameter is 10 mm. This suggests that the thin system can use low-temperature hot water for effective energy-saving heating. The above research results can thoughtfully provide theoretical guidance for radiant floor heating.
Nitric oxide (NO) is involved not only in the regulation of plant growth, development, and stress responses but also in the regulation of plant-microbe interactions. Here, we demonstrate that ...Piriformospora indica can induce tobacco nitrate reductase to produce a NO signal in roots which enhances nitrogen uptake capacity by inducing the expression of ammonium and nitrate transporter genes and the development of lateral root and root hair, thereby promoting tobacco growth. In addition, the NO signal induced by P. indica is significantly different from that induced by the pathogen Phytophthora nicotianae. Inoculation with P. indica did not produce H
2
O
2
and maintained high expression of Phytoglobin 1 in roots, resulting in a significantly lower NO level than in the roots inoculated with P. nicotianae. These findings suggest that an appropriate NO level is the likely basis of plant-P. indica symbiosis, which promotes the growth of host plants.
Refrigerant filling is a process of transitioning from compressed liquid to gas-liquid discrete state, which poses difficulties in monitoring the quality of refrigerant charging. This paper proposed ...a novel approach based on physics-informed deep learning for refrigerant filling mass flow metering. First, a shock discontinuity flow physical model is established related to the refrigerant filling mass flow rate, velocity and pressure. Additionally, a filling mass metering method based on PINN is proposed, as well as a residual points-adding optimization method for PDEs with discontinuous solution. The results demonstrate that PINN accurately predict mass flow rate, pressure, and velocity for refrigerant filling, and the error relative to numerical solution is less than 3%. Finally, a refrigerant filling experiment was conducted to verify the feasibility of the method of refrigerant mass flow metering.
•Predict mass flow during refrigerant filling using Physics-informed Neural Network.•A circulating flow experimental device was established.•A residual points-adding optimization method is proposed for PDEs with discontinuous solution.
The energy release from an aluminum dust explosion is related to the degree of turbulence and the local concentration distribution at a given nominal concentration. In the present work, the combined ...effects of turbulence and concentration on aluminum dust/air explosions in a 20 L spherical test vessel were examined using ultrasonic sensors. The relationship between the dust concentration and the ultrasonic attenuation coefficient was established, and real-time online measurements of aluminum dust concentrations were performed. The data show that the turbulent kinetic energy increases sharply during the initial stage of injection and then decreases gradually over time, while the concentration and uniformity of suspended dust gradually increase as the turbulence decreases. Explosion energy data were obtained at various dust concentrations and demonstrate that concentrations from 700 to 900 g/m3 are optimal.
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•The ultrasonic signal spectrum had been obtained based on the Hilbert-Huang Transform.•The aluminum dust concentration had been calculated based on the amplitude attenuation of the pulsed ultrasonic frequency.•The results of calculations about turbulence been compared with experimental data.•The concentration distribution and uniformity of aluminum dust diffusion had been analyzed.•Explosion energy data were obtained at different aluminum dust concentrations.
An appropriate concentration of micro/nano aluminum powder (MNAP) cloud is necessary for fuel air explosive (FAE) detonation. However, because of the fast dynamics, uncertainty interference, and ...transient characteristics of MNAP diffusion, experimental research on the measurement of MNAP cloud concentration is still lacking. Here, a pair of ultrasonic transducers were developed based on pulse drive, to measure the dynamic MNAP cloud concentration during MNAP diffusion in a standard 20-L explosion vessel. The measurement method was based on Lloyd-Berry ultrasonic attenuation theory. The experimental results showed that the ultrasonic pulse had a strong anti-interference ability, high precision, and real-time response to enable the characterization of MNAP diffusion concentration. The diffusion concentration gradients of MNAP were established and agreed well with the trend predicted by computational fluid dynamics simulations. The results also indicated that aluminum nanoparticles have better distribution characteristics than those of aluminum microparticles. These analyses provide technical support to improve FAE detonation energy.
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•Thecalculation modelis establishedofMNAP concentrationbased on Lloyd and Berry ultrasonic scattering model.•The restrictions and approximations of the used attenuation model has been detailed stated.•A CFD simulation model isestablished to analysisthe distributioncharacteristics of MNAPconcentrationcomparatively.•A dynamic concentration measurement systemof MNAPisestablishedin the 20-L spherical vessel.•The results shown thatthe feasibility and noveltyof the dynamic concentration detection system.
This study aimed to investigate the clinical characteristics, distribution of different strains and risk factors of patients infected with Streptococcus anginosus group (SAG). In the population of ...463 patients, the male-to-female ratio was 1.95:1, and the patient age ranged from 6 months to 103 years. There were 49 children (10.58%), 311 young and middle-aged adults (67.17%), and 103 elderly adults (22.25%). Approximately 45.4% had underlying conditions, which were mostly malignant tumors and diabetes. Of the 463 specimens, 254 were S. anginosus (54.86%), 173 were S. constellatus (37.37%), and 36 were S. intermedius (7.77%). According to the age distribution, the incidence peaked in the 35-54 year age group. Different sites of infection had statistically significant differences regarding the constituent ratios of these three species. Different age groups also exhibited statistically significant differences in constituent ratios of the pathogenic organisms, as well as organ infections. In our population, 269 were clinically cured, 184 reported satisfactory improvement, and 10 died. SAG, as an opportunistic pathogen, can induce pyogenic infections in patients of all ages and shows no significant gender predilection in any age group. The three pathogenic organisms had differences with respect to patient age and infections of body sites.
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