[Invited] Phononic crystal for dynamic viscosity determination: [Invited]

International audienceWe propose a two-dimensional triangular lattice solid/fluid phononic crystals (PnC) for the determination of the acoustic properties and in particular dynamic viscosity of a fluid. We show that this device is very sensitive to the acoustic parameters of the liquid, such as density or sound velocity, and could consequently be used as a temperature sensor. This temperature sensitivity is investigated through the existence of sharp waveguide acoustic modes localized in the band gap of the PnC at well-defined frequencies. We show that this device can also be used for dynamic viscosity measurements of liquid, based on the attenuation of the guided modes

Temperature biosensor based on triangular lattice phononic crystals

International audienceA two-dimensional triangular lattice solid/fluid phononic crystal (PnC) is proposed as a sensitive biosensor to detect the temperature of the Methyl Nonafluorobutyl Ether (MNE) in the range of 10-40 degrees C. Temperature changes in MNE represent an important issue for its various applications. Indeed, the MNE is widely used in cosmetic and beauty products for its non-toxic, non-flammable, and colorless chemical properties. For this purpose, a sensitive biosensor for temperature and physical properties of MNE appears necessary. The PnC biosensor consists of a triangular lattice of tungsten cylinders embedded in an epoxy background inside of which a line of hollow cylinders filled with MNE is introduced as a waveguide for guiding resonant modes with low group velocity. We show that the PnC biosensor provides sharp guided modes in the bandgap with high quality factors and frequencies depending on the MNE temperature with high sensitivity. The introduction of damping inside the liquid shows that the shear viscosity, compared to longitudinal, affects drastically the amplitude of the resonant peaks. However, the length of the waveguide can be adapted so as to recover the resonant peak in the presence of viscosities

Improvement of dragonhead ( Dracocephalum moldavica

The effects of an intercropping system combined with organic fertilizer application on the yield quality of medicinal plants and the involved mechanisms have not been well elucidated. To evaluate the effects of different fertilizers (vermicompost and chemical fertilizers) on the dragonhead essential oil (DEO) productivity (dragonhead = Dracocephalum moldavica L.) (D) in sole cropping and intercropping with common bean (Phaseolus vulgaris L.) (CB), a 3-year field experiment was carried out using a factorial based on randomized complete block design. We found that the highest common bean seed yield and dry matter productivity of dragonhead were obtained from sole cropping fertilized with vermicompost. Regarding the major DEO constituents, the highest content of geranyl acetate (42.2%), geranial (23.4%), and geraniol (17.81%) were recorded using the cropping ratio of 2D:1CB following the use of vermicompost. Soil micro-biochemical parameters (basic microbial respiration, substrate-induced respi- ration, microbial biomass carbon, alkaline and acid phosphatase, and urease) in the intercropping systems were found to be higher than those of the corresponding sole croppings. The highest soil microbial activity was observed in the intercropping ratios of 2D:1CB and 1D:2CB following the use of vermicompost. Furthermore, the highest land equivalent ratios (LER = 1.28) were achieved in the intercropping ratio 2D:1CB after vermicompost application. Thus, this combination of stimulated soil microbial activity and functionality, which in turn accelerated nutrient mobilization and availabil- ity, enhanced plant performance. Therefore, we can conclude that intercropping drag- onhead with common bean at the ratio of 2D:1CB coupled with vermicompost application can be introduced as an alternative and sustainable strategy to reduce the use of chemical fertilizers