Combination of organic acid and heat–moisture treatment: impact on the thermal,structural, pasting properties and digestibility of maize starch

Journal of Thermal Analysis and Calorimetry - Maize is the most important source of starch used for industrial applications. Its starch properties can be improved by either single or double...     

Hydrolysis of the low gelatinization temperature Araucaria angustifolia pine seed starch

Journal of Thermal Analysis and Calorimetry - The effect of compressor speed, initial refrigerant charge and volume concentrations of SiO2/PAG nanolubricant on the performance of automotive...     

Aqueous extraction of organic amaranth starch and their by-products

Journal of Thermal Analysis and Calorimetry - The aim of this study was to characterise the organic amaranth flour (Amaranthus caudatus), native starch and by-products generated after its aqueous...     

Symmetric Graphs from Polytopes of High Rank

Given a polytope ${{\mathcal{P}}}$ of rank 2n, the faces of middle ranks n ? 1 and n constitute the vertices of a bipartite graph, the medial layer graph ${{M(\mathcal{P})}}$ of ${{\mathcal{P}}}$ . The group ${{D(\mathcal{P})}}$ of automorphisms and dualities of ${{\mathcal{P}}}$ has a natural action on this graph. We prove algebraic and combinatorial conditions on ${{\mathcal{P}}}$ that ensure this action is transitive on k-arcs in ${{M(\mathcal{P})}}$ for some small k (in particular focussing on k?=?3), and provide examples of families of polytopes that satisfy these conditions. We also examine how ${{D(\mathcal{P})}}$ acts on the k-stars based at vertices of ${{M(\mathcal{P})},}$ and describe self-dual regular polytopes (in particular those of rank 6) for which this action is transitive on the k-stars for small k.     

On the enumerative nature of Gomory’s dual cutting plane method

For 30 years after their invention half a century ago, cutting planes for integer programs have been an object of theoretical investigations that had no apparent practical use. When they finally proved their practical usefulness in the late eighties, that happened in the framework of branch and bound procedures, as an auxiliary tool meant to reduce the number of enumerated nodes. To this day, pure cutting plane methods alone have poor convergence properties and are typically not used in practice. Our reason for studying them is our belief that these negative properties can be understood and thus remedied only based on a thorough investigation of such procedures in their pure form. In this paper, the second in a sequence, we address some important issues arising when designing a computationally sound pure cutting plane method. We analyze the dual cutting plane procedure proposed by Gomory in 1958, which is the first (and most famous) convergent cutting plane method for integer linear programming. We focus on the enumerative nature of this method as evidenced by the relative computational success of its lexicographic version (as documented in our previous paper on the subject), and we propose new versions of Gomory’s cutting plane procedure with an improved performance. In particular, the new versions are based on enumerative schemes that treat the objective function implicitly, and redefine the lexicographic order on the fly to mimic a sound branching strategy. Preliminary computational results are reported.     

Access to 2,3-diaryl-4-nitrothiochroman S,S-dioxides from 3-nitrobenzo[b]thiophene

The base-induced cyclization of (E)-2-aryl-1-[2-(benzylsulfonyl)phenyl]-1-nitroethenes to polysubstituted thiochroman S,S-dioxides exhibits a diastereoselectivity that can be oriented towards a selected isomer by means of appropriate adjustments of the experimental conditions. The interest of such a result also rests on the promising pharmacological activity of the products, whose structure encompasses different well-acknowledged pharmacophores. A conformational ¹H NMR investigation, backed by molecular-mechanics calculations, has also been accomplished.     

Thermodynamic properties of 1-butyl-3-methylpyridinium tetrafluoroborate

Pressure, density, temperature (p, ρ, T) data of 1-butyl-3-methylpyridinium tetrafluoroborate [C4mpyr][BF₄] at T = (283.15 to 393.15) K and pressures up to p = 100 MPa are reported with an estimated experimental relative combined standard uncertainty of Δρ/ρ = ±(0.01 to 0.08)% in density. The measurements were carried out with a newly constructed Anton-Paar DMA HPM vibration-tube densimeter. The system was calibrated using double-distilled water, methanol, toluene and aqueous NaCl solutions. An empirical equation of state for fitting of the (p, ρ, T) data of [C4mpyr][BF₄] has been developed as a function of pressure and temperature to calculate the thermal properties of the ionic liquid (IL), such as isothermal compressibility, isobaric thermal expansibility, differences in isobaric and isochoric heat capacities, thermal pressure coefficient and internal pressure. Internal pressure and the temperature coefficient of internal pressure data were used to make conclusions on the molecular characteristics of the IL.