Kinetic study of spiramycin removal from aqueous solution using heterogeneous photocatalysis

International audienceSpiramycin macrolide antibiotic (SPM) can be photocatalytically degraded on TiO2 (anatase variety). The experiments are done in a batch reactor and the effect of some key parameters is investigated under low energy of artificial UV light. The reaction rate is affected by varying TiO2 dose, pH and SPM concentration. Under optimized conditions, a photodegradation efficiency of 98% is achieved and the SPM photodegradation follows pseudo-first order kinetics. The Langmuir–Hinshelwood (L–H) model is successfully used to fit the experimental data, indicating the dependence of the reaction rate on the chemical reaction step. The L–H model led to the determination of both reaction kinetic and adsorption/desorption equilibrium constants. In order to give an overall estimate of the by-products, chemical oxygen demand, total organic carbon, and calculated average oxidation state monitor the photodegradation proces

Short Digital Signatures and ID-KEMs via Truncation Collision Resistance

Truncation collision resistance is a simple non-interactive complexity assumption that seems very plausible for standard cryptographic hash functions like SHA-3. We describe how this assumption can be leveraged to obtain standard-model constructions of public-key cryptosystems that previously seemed to require a programmable random oracle. This includes the first constructions of identity-based key encapsulation mechanisms (ID-KEMs) and digital signatures over bilinear groups with full adaptive security and without random oracles, where a ciphertext or signature consists of only a single element of a prime-order group. We also describe a generic construction of ID-KEMs with full adaptive security from a scheme with very weak security ( selective and non-adaptive chosen-ID security ), and a similar generic construction for digital signatures

A numerical model for vibro-acoustic problems with sheared mean flows

A model based on Galbrun's equation is proposed to address the problem of vibro-acoustic interactions in sheared flows. The use of a displacement-pressure mixed formulation of Galbrun's equation greatly simplifies the coupling condition formulations and avoids the problem of non-zero frequency spurious modes encountered with displacement-based acoustic formulations. This model is applied to duct acoustics. Comparisons with analytical models demonstrate the accuracy of the method. The effects of mean flow shear on acoustic wave propagation in elastic ducts are then illustrated