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The shock‐compression responses of PTFE (polytetrafluoroethylene)/Al granular composites subjected to planar shock waves of various pressures are investigated. A 57‐mm diameter single‐stage gas‐gun and 50‐mm diameter plane‐wave lenses are employed to perform planar shock wave experiments. High frequency manganin piezoresistance stress gauges are used to monitor the stress (regarded as pressure in consideration of the high pressure state) at four Lagrangian positions of the PTFE/Al granular composites specimens. Planar shock wave experiments show characteristics of densification at measured input pressure of 0.5 GPa to 1.27 GPa using single‐stage gas‐gun and shock‐induced reaction (SIR) indicated by growth of shock pressure and specific volume expansion at measured input pressure of 7.29 GPa to 12.25 GPa using plane‐wave lenses. The pressure and relative volume states behind the shock wave front are calculated from the experimental recorded pressure profiles using Lagrangian analysis method, which are used to determine the reaction ratios under different shock pressures by comparing with partial reacted Hugoniot calculations. It was shown that the reaction ratios obtained in this research have good agreement with the thermochemical modeling calculations. The corresponding results indicate that the shock‐induced reactions of PTFE/Al granular composites occur in the shock wave rising period and the reaction ratios are intimately related to the shock wave pressure.

An investigation has been made to study the reaction kinetics of gelled acids with calcite using a rotating disk apparatus. The rheological experiments revealed that all gelled acids behaved as non-Newtonian shear thinning fluids. With the rotating disk apparatus, the reaction kinetics parameters, activation energy, and effective diffusion coefficients were determined. It was found that the reaction of gelled acid with calcite was mass transfer limited at low polymer concentration and moving toward surface reaction limited at higher polymer concentration. And the diffusion rate marginally decreased, with increasing the polymer concentration.

The influence of feedstock and pyrolysis temperature on biochar properties has been extensively studied. This study used scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDX) to observe surface morphology properties of the biochars produced from broiler litter (BL), saw dust (SD), furfural residue (FR) at 300-700 °C. The SEM images showed that the biochars from SD and FR clearly retained fibrous structures of the feedstocks and were rich in macro-pores. Similarly, the FR-derived biochars produced at 500 and 700 °C contained larger quantity of pores compared to that of the FR300. The particles with irregular shape on the surface of these biochars reduced with increasing temperature, suggesting that their surface morphology changed greatly during charring at higher temperature. Mineral elements (e.g. K, Mg, and P) were found in the FR-derived biochars. The abundant pores and minerals in the biochars are helpful for ameliorating soil through the supplies of micro spaces and mineral nutrition .

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Effective shielding area is a crucial indicator for the evaluation of the infrared smoke-obscuring effectiveness on the battlefield. The conventional methods for assessing the shielding area of the smoke screen are time-consuming and labor intensive, in addition to lacking precision. Therefore, an efficient and convincing technique for testing the effective shielding area of the smoke screen has great potential benefits in the smoke screen applications in the field trial. In this study, a thermal infrared sensor with a mid-wavelength infrared (MWIR) range of 3 to 5 μm was first used to capture the target scene images through clear as well as obscuring smoke, at regular intervals. The background subtraction in motion detection was then applied to obtain the contour of the smoke cloud at each frame. The smoke transmittance at each pixel within the smoke contour was interpolated based on the data that was collected from the image. Finally, the smoke effective shielding area was calculated, based on the accumulation of the effective shielding pixel points. One advantage of this approach is that it utilizes only one thermal infrared sensor without any other additional equipment in the field trial, which significantly contributes to the efficiency and its convenience. Experiments have been carried out to demonstrate that this approach can determine the effective shielding area of the field infrared smoke both practically and efficiently.

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Structural stability in terms of the decomposition temperature in LiMn2O4 was systematically investigated by a series of high-temperature and high-pressure experiments. LiMn2O4 was found to have structural stability up to 5 GPa at room temperature. Under ambient pressure, the compound decomposed at 1300 °C. The decomposition temperature decreased with increasing pressure, yielding more complex decomposed products, Below the decomposition temperature, the crystal structure of LiMn2O4 varied with pressure. The presented results in this study offer new insights into the thermal and pressure stability of LiMn2O4 materials as a cathode for lithium-ion batteries that can operate under extreme conditions. Therefore, these findings may serve as a useful guide for future work for improving lithium-ion batteries.