H2O and CO2 Dilution in MILD Combustion of Simple Hydrocarbons

MILD combustion is a very attractive technology because of its intrinsic features for energy production from diluted gas deriving from bio- or thermochemical degradation of biomass. An effective use of such a technology for diluted fuel requires a thorough analysis of ignition and oxidation behavior to highlight the potential effects of the different fuel components on the basis of temperature and diluent/oxygen/fuel mixture composition. In this work, ignition and oxidation of a model gas surrogate for the gaseous fraction of biomass pyrolysis products containing C₁-C₂ species, CO and CO₂ were experimentally and numerically studied over a wide range of temperature and overall composition in the presence of large amounts of CO₂ or H₂O. Experimental results showed that such species significantly alter the evolution of the ignition process in dependence on temperature range and mixture composition. Several kinetic models were tested to simulate experimental results. Significant discrepancies occur, especially in the case of steam dilution. Numerical analyses suggested that such diluents acted mainly as third body species at low temperatures, conditioning both radical production pathways and the relative weight of C₁ oxidation/recombination routes, while strongly interacting with the H₂/O₂ high temperature branching mechanisms at high temperatures. Further analyses are mandatory to improve the predictability of the models and extend the applicability of the chemical schemes to non-standard conditions.     

Advances in thermoanalytical techniques

Journal of Thermal Analysis and Calorimetry - Thermogravimetry coupled with chemometrics has proved to be a rapid and cost-effective diagnostic tool for β-thalassemia screening. This model,...     

Intracellular concentration map of magnesium in whole cells by combined use of X-ray fluorescence microscopy and atomic force microscopy

We report a novel experimental approach to derive quantitative concentration map of light elements in whole cells by combining two complementary nano-probe methods: X-ray fluorescence microscopy (XRFM) and atomic force microscopy (AFM). The concentration is derived by normalizing point-by-point the elemental (here Mg) spatial distribution obtained by XRFM, by the thickness measured using AFM. The considerable difference between the elemental distribution and the concentration maps indicates that this procedure is essential to obtain reliable information on the role and function of elements in whole cells.     

Effects of the network structural properties on its controllability

In a recent paper, it has been suggested that the controllability of a diffusively coupled complex network, subject to localized feedback loops at some of its vertices, can be assessed by means of a Master Stability Function approach, where the network controllability is defined in terms of the spectral properties of an appropriate Laplacian matrix. Following that approach, a comparison study is reported here among different network topologies in terms of their controllability. The effects of heterogeneity in the degree distribution, as well as of degree correlation and community structure, are discussed.     

A procedure to achieve fine control in MW processing of foods

A two-dimensional analytical model for predicting the unsteady temperature field in a cylindrical shaped body affected by spatially varying heat generation is presented. The dimensionless problem is solved analytically by using both partial solutions and the variation of parameters techniques. Having in mind industrial microwave heating for food pasteurization, the easy-to-handle solution is used to confirm the intrinsic lack of spatial uniformity of such a treatment in comparison to the traditional one. From an experimental point of view, a batch pasteurization treatment was realized to compare the effect of two different control techniques both based on IR thermography readout: the former assured a classical PID control, while the latter was based on a “shadowing” technique, consisting in covering portions of the sample which are hot enough with a mobile metallic screen. A measure of the effectiveness of the two control techniques was obtained by evaluating the thermal death curves of a strain Lactobacillus plantarum submitted to pasteurization temperatures. Preliminary results showed meaningful increases in the microwave thermal inactivation of the L. plantarum and similar significant decreases in thermal inactivation time with respect to the traditional pasteurization thermal treatment.     

Rigorous analysis of 3D optical and optoelectronic devices by the Compact-2D-FDTD method

Continous advances in material technology, in the field of integrated optics and optoelectronics, allow the realization of devices with geometries more and more compact and complex. Because of this trend, there is a parallel need for accurate fully numerical CAD tools. Among new ones, the FDTD method, already widely and successfully used for the characterization of microwave and millimeter-wave devices, is emerging in optics community because of its accuracy and versatility. However, in spite of the tremendous increase in computing power, the applicability of the method is still limited by the typical dimensions of optical structures. To overcome these limitations a specialized version of the FDTD algorithm for the rigorous analysis of 3D optical and optoelectronic devices is proposed and validated. This new technique is then used to characterize the optical behaviour of a MQW waveguide electroabsorption modulator.     

Symplectic and contact properties of the Mañé critical value of the universal cover

We discuss several symplectic aspects related to the Mañé critical value c _u of the universal cover of a Tonelli Hamiltonian. In particular we show that the critical energy level is never of virtual contact type for manifolds of dimension greater than or equal to three. We also show the symplectic invariance of the finiteness of the Peierls barrier and the Aubry set of the universal cover. We also provide an example where c _u coincides with the infimum of Mather’s α function but the Aubry set of the universal cover is empty and the Peierls barrier is finite. A second example exhibits all the ergodic invariant minimizing measures with zero homotopy, showing, quite surprinsingly, that the union of their supports is not a graph, in contrast with Mather’s celebrated graph theorem.     

Structure-Activity Relationship of NF023 Derivatives Binding to XIAP-BIR1

Inhibitors of Apoptosis Proteins (IAPs) are conserved E3-ligases that ubiquitylate substrates to prevent apoptosis and activate the NF-kB survival pathway, often deregulated in cancer. IAPs-mediated regulation of NF-kB signaling is based on the formation of protein complexes by their type-I BIR domains. The XIAP-BIR1 domain dimerizes to bind two TAB1 monomers, leading to downstream NF-kB activation. Thus, impairment of XIAP-BIR1 dimerization could represent a novel strategy to hamper cell survival in cancer. To this aim, we previously reported NF023 as a potential inhibitor of XIAP-BIR1 dimerization. Here we present a thorough analysis of NF023 binding to XIAP-BIR1 through biochemical, biophysical and structural data. The results obtained indicate that XIAP-BIR1 dimerization interface is involved in NF023 binding, and that NF023 overall symmetry and the chemical features of its central moiety are essential for an efficient interaction with the protein. Such strategy provides original hints for the development of novel BIR1-specific compounds as pro-apoptotic agents.