Rheological properties of starch suspensions using a rotational rheometer fitted with a starch stirrer cell

The rheological properties of a starch suspension are usually studied through two viscosity measurements-pasting behavior and flow behavior of the resulting starch pastes-performed separately with two different tools and demanding rather high starch concentrations (6–10 wt %). This study focused on the feasibility of using a rheometer fitted with a starch stirrer cell to characterize, in a single experiment, the starch suspension’s behavior during and after pasting, all the while involving only low concentrations (2–4 wt %), more representative of a real-food context. A calibration of the starch stirrer cell in comparison to the coaxial cylinders one was done using model fluids (Newtonian and shear-thinning). A link between torque, rotational speed, and rheological properties was determined through two recalculated conversion factors (shear rate and shear stress). An operating diagram was then set indicating the laminar flow and good sensitivity domain for this cell. The accuracy of those constants to starch suspensions in the concentration range 2–4 wt % was demonstrated. The pasting behaviors of 2 wt % starch suspensions were followed successfully at two selected shear rates (13.5 and 135 s^?1). The impact of the level of turbulence on the profiles obtained was stressed, a result that is not limited to low-concentration starch suspensions. Finally, the method developed was used to compare the pasting behaviors of 2 wt % native and modified waxy maize starch suspensions.     

Stochastic invariance of closed sets with non-Lipschitz coefficients

This paper provides a new characterization of the stochastic invariance of a closed subset of ${\mathbb{R}}^d$ with respect to a diffusion. We extend the well-known inward pointing Stratonovich drift condition to the case where the diffusion matrix can fail to be differentiable: we only assume that the covariance matrix is. In particular, our result can be applied to construct affine and polynomial diffusions on any arbitrary closed set.     

Copper-Based Hybrid Polyion Complexes for Fenton-Like Reactions

An innovative strategy allowing the development of a new generation of easy-to-prepare and easy-to-use nano-sized catalysts with high tenability is presented. This strategy is based on the formation of hybrid polyion complexes (HPICs) from the complexation of copper with a block copolymer consisting of an ionizable complexing block and a neutral stabilizer block. These complexes have a well-defined structure and size with a hydrodynamic diameter around 29 nm. They are stable in aqueous solution over a pH range from 4 to 8 and are not sensitive to NaCl salt addition or dilution effects. As a proof-of-concept the degradation of naphthol blue black in water through the use of the Fenton or photo-Fenton reaction is studied. Their performances are comparable to a classical homogeneous reaction, whereas HPICs are easily recyclable by simple dialysis.     

Radiation-induced cavities in aluminium alloy imaged by in line electron holography

In irradiated material, cavities result from the condensation of vacancies induced by collision cascades. The study of their formation is a relevant topic since a high density of cavities may alter significantly the material performance. In this work, a simplified version of in line holography was successfully applied for imaging cavities in ion-irradiated 6061 aluminium alloy. In transmission electron microscopy, the incoming electrons experience a phase shift owing to the potential variation induced by the cavities. The retrieval of this phase shift provides a convenient map to observe and highlight the cavities. Information on density of cavities can be easily obtained. In addition, interstitial clusters may also be detected.     

Plasticity of formable all-metal sandwich sheets: Virtual experiments and constitutive modeling

The mechanical behavior of a metallic sandwich sheet material composed of two flat face sheets and two bi-directionally corrugated core layers is analyzed in detail. The manufacturing of the sandwich material is simulated to obtain a detailed unit cell model which accounts for the non-uniform thickness distribution and residual stresses associated with the stamping of the core layers. Virtual experiments are performed by subjecting the unit cell model to various combinations of bi-axial in-plane loading including the special cases of uniaxial tension, uniaxial compression, equi-biaxial tension and shear. The results demonstrate that the core structure’s contribution to the in-plane load carrying capacity of the sandwich sheet material is similar to that of the face sheets. The numerical results are also used to identify the effective yield surface and hardening response of both the core layer and the face sheets. An anisotropic yield function with linear pressure dependency is proposed to approximate the equal-plastic work surfaces for the core structure and face sheets. Furthermore, a new two-surface model with non-linear interpolation based on plastic work density is presented to describe the observed combined isotropic-distortional hardening of the core structure.     

Integration of holomorphic Lie algebroids

We prove that a holomorphic Lie algebroid is integrable if and only if its underlying real Lie algebroid is integrable. Thus the integrability criteria of Crainic–Fernandes (Theorem 4.1 in Crainic, Fernandes in Ann Math 2:157, 2003) do also apply in the holomorphic context without any modification. As a consequence we prove that a holomorphic Poisson manifold is integrable if and only if its real part or imaginary part is integrable as a real Poisson manifold.     

Jet schemes and minimal toric embedded resolutions of rational double point singularities

Using the structure of the jet schemes of rational double point singularities, we construct “minimal embedded toric resolutions” of these singularities. We also establish, for these singularities, a correspondence between a natural class of irreducible components of the jet schemes centered at the singular locus and the set of divisors which appear on every “minimal embedded toric resolution”. We prove that this correspondence is bijective except for the E₈ singulartiy. This can be thought as an embedded Nash correspondence for rational double point singularities.     

Impact of nitric oxide on n-heptane and n-dodecane autoignition in a new high-pressure and high-temperature chamber

A New One Shot Engine (NOSE) was designed to simulate the thermodynamic conditions at High Pressure-High Temperature like an actual common-rail diesel engine in order to study the compression ignition of spray. The volume of the combustion chamber provided with large optical windows simplified the implementation of various optical diagnostics. The advantage of this kind of set-up in comparison to pre-burn or flue chambers is that the initial gas mixture can be well controlled in terms of species and mole fraction. The purpose of this work was to investigate the impact of nitric oxide (NO) on ignition delay (ID) for two fuels with different cetane numbers: n-heptane, and n-dodecane. In the thermodynamic conditions chosen (60?bar and over 800–900?K), NO had a strong effect on ID, with increases in NO tending to reduce the ignition delay. Results showed that ID and Lift-Off Length (LOL) presented the same trend as a function of temperature and NO concentration. Experimentally, at 900?K the ignition of n-dodecane was promoted by NO up to 100?ppm, whilst higher NO levels did not further promote ignition and a stabilization of the value has been noticed. For n-heptane, stronger promoting effects were observed in the same temperature conditions: the ignition delays were monotonically reduced with up to 200?ppm NO addition. At a lower temperature (800?K) the inhibiting effect was observed for n-dodecane for [NO] greater than 40?ppm, whereas only a promoting effect was observed for n-heptane. The experimental results of LOL showed that NO shortened LOL in almost all cases, and this varied with both the NO concentration and the mixture temperature. Thus, fuels with shorter ignition delays produce shorter lift-off lengths.