Enthalpy Probe Technique for Thermal Plasma Diagnostics

The measuring principle and experimental results of the enthalpy probe technique for thermal plasma diagnostics are presented. Its calibration and errors are discussed. Typical results are presented for the system operation in an Ar/H2(5 % H2) plasma arc jet under a reactor chamber pressure of 101.3 kPa. The plasma temperature and velocity profiles are measured. The center temperature and velocity are 6600 K and 850 m/s for plasma power 9 kW at axial location of 17 mm.

Quantitatively probing interactions between membrane with adaptable wettability and oil phase in oil/water separation

The membrane method based on adaptive wettability shows great advantages in oil-water separation.At present,researches focus on the excellent application performance of the membrane material,while the quantitative analysis of interactions in oil-water separation is rarely recognized.Herein,we constructed an adaptable wettability membrane with multiple polymer networks by polydopamine(PDA)and mussel-inspired amphiphilic polymer.Based on the Owens three-probe liquid method,the surface energy of the modified membrane was verified to meet the adaptive wettability conditions,with surface energies(γ-8)of 147.6 mJ m^(−2)(superhydrophilic/underwater superoleophobic)and 49.87 mJ m^(−2)(superhydrophobic/superoleophobic),respectively.The adhesion or repulsion of the membrane to the oil phase under different conditions during the separation process was quantified by the chemical probe AFM technique.In addition,the oil-water selective separation mechanism was further analyzed in a simplified membrane microchannel model.The results show that the different wetting produces capillary additional pressure in opposite directions,resulting in different energies to be overcome when the oil or water passes through the microchannels,thus achieving selective separation.

Effect of surface roughness on sliding friction of micron-sized glass beads

In order to understand the contact phenomena of micron‐sized particles,which have a tremendous impact on a variety of applications in industry and technology,direct access to the loads as well as the displacements accompanying such contacts are mandatory.Typical particle ensembles show a size variation ranging from the nanometer to the tenths of micron scale.Especially the contact behavior of particles featuring radii of several up to several tenths of microns is scarcely studied as these particles are typically too large for atomic force microscopy(AFM)based approaches and too small for conventional macroscopic testing setups.In this work a nanoindenter based approach is introduced to gain insight into the contact mechanics of micron‐sized glass beads sliding on rough silicon surfaces at various constant low normal loads.The results are analyzed by a simple modified Coulomb friction law,as well as Hertz,JKR,and DMT contact theory.

The measurement and model construction of complex permittivity of vegetation

The complex permittivity of targeted objects is an important factor that influences its microwave radiation and scattering characteristics.In the quantitative research of microwave remote sensing,the study of the dielectric properties of the vegetation to establish the relationship between its specific physical parameters and complex permittivity is fundamental.In this study,six categories of vegetation samples were collected at the city of Zhangye,a key research area of the Heihe watershed allied telemetry experimental research.The vector network analyzer E8362B was used to measure the complex permittivity of these samples from 0.2 to 20 GHz by the coaxial probe technique.The research focused mainly on the corn leaves,and an empirical model was established between the gravimetric moisture and the real/imaginary parts of complex permittivity at the main frequency points of microwave sensors.Furthermore,the empirical model and the classical Debye-Cole model were compared and verified by the measured data collected from the Huailai County of Hebei Province.The results show that the newly- established empirical model is more accurate and more practical as compared to the traditional Debye-Cole model.