The Balassa–Samuelson effect in Romania – The role of regulated prices

Due to the Balassa–Samuelson effect, the candidate countries to the European Monetary Union face a possible conflict between the effects of tradable productivity increase on inflation and on the appreciation of the real exchange rate on one hand, and the Maastricht criteria regarding inflation and exchange rate stability on the other hand. A restrictive monetary policy could succeed in reaching inflation criteria, but only with the cost of slowing down real convergence. This paper deals with the Balassa–Samuelson effect in Romania. The main conclusion of the paper is that in the period 1998–2006 the average annual rate of inflation generated by the Balassa–Samuelson effect in Romania was on average 0.6% in the case of the classical model. Due to the existence of government-regulated prices (mostly non-tradable goods) accounting for as much as 21% of the CPI basket in Romania – the price of non-tradables has increased by less than in the case those prices were market prices. If we include these regulated prices in non-tradable, which is named by us extended model, the impact of Balassa–Samuelson on inflation could have been on average 2.46%. Therefore, the Balassa–Samuelson effect is expected to result into higher inflation with future price liberalization for non-tradables.     

Modeling of L-lactide Polymerization by Reactive Extrusion

The kinetics of L-lactide ring-opening polymerization initiated by stannous octoate and triphenylphosphine was investigated in a batch apparatus (Haake Rheocord Mixer). Based on the experimental data, a kinetic model is developed, considering a coordination-insertion mechanism. Reactive extrusion experiments were further conducted for the same polymerization process, on a co-rotating twin screw extruder. The melted material flow and mixing was described by using the Ludovic® commercial simulator. Based on the developed kinetic model and simulated flow of L-lactide polymerization mixture, a mathematical model of reactive extrusion process is formulated, describing the evolutions of monomer conversion and average molecular weight along the extruder. The model is predicting with a reasonable good accuracy the experimental data.     

Derived Hilbert schemes

We construct the derived version of the Hilbert scheme parametrizing subschemes in a given projective scheme with given Hilbert polynomial . This is a dg-manifold (smooth dg-scheme) which carries a natural family of commutative (up to homotopy) dg-algebras, which over the usual Hilbert scheme is given by truncations of the homogeneous coordinate rings of subschemes in . In particular, differs from , the derived Quot scheme constructed in our previous paper, which carries only a family of -modules over the coordinate algebra of .

As an application, we construct the derived version of the moduli stack of stable maps of algebraic curves to a given projective variety , thus realizing the original suggestion of M. Kontsevich.

     

Antibacterial and Photocatalytic Properties of ZnO Nanoparticles Obtained from Chemical versus Saponaria officinalis Extract-Mediated Synthesis

In the present work, the properties of ZnO nanoparticles obtained using an eco-friendly synthesis (biomediated methods in microwave irradiation) were studied. Saponaria officinalis extracts were used as both reducing and capping agents in the green nanochemistry synthesis of ZnO. Inorganic zinc oxide nanopowders were successfully prepared by a modified hydrothermal method and plant extract-mediated method. The influence of microwave irradiation was studied in both cases. The size, composition, crystallinity and morphology of inorganic nanoparticles (NPs) were investigated using dynamic light scattering (DLS), powder X-ray diffraction (XRD), SEM-EDX microscopy. Tunings of the nanochemistry reaction conditions (Zn precursor, structuring agent), ZnO NPs with various shapes were obtained, from quasi-spherical to flower-like. The optical properties and photocatalytic activity (degradation of methylene blue as model compound) were also investigated. ZnO nanopowders’ antibacterial activity was tested against Gram-positive and Gram-negative bacterial strains to evidence the influence of the vegetal extract-mediated synthesis on the biological activity.     

A Study of L-Lactide Ring-Opening Polymerization Kinetics

Summary: The paper presents an experimental study of L-lactide polymerization in molten state using as initiator the Stannous Octoate. The experiments were performed in a Haake mixer. The operating temperatures were between 170 and 195°C, the reaction time up to 60 min and monomer to initiator initial molecular ratio between 10² and 5 · 10³. The conversion was determined by using ¹H NMR and the molecular weights distributions by SEC. A preliminary mathematical modeling study was also performed, based on experimental data and a previously published reaction scheme.     

Specified discharge velocity models for numerical simulations of laminar vortex rings

We numerically and theoretically investigate the flow generated at the exit section of a piston/cylinder arrangement that is generally used in experiments to produce vortex rings. Accurate models for the velocity profile in this section (also called specified discharge velocity, SDV models) are necessary in (i) numerical simulations of laminar vortex rings that do not compute the flow inside the cylinder and (ii) in slug-models that provide a formula for the total circulation of the flow. Based on the theoretical and numerical analysis of the flow evolution in the entrance region of a pipe, we derive two new and easy to implement SDV models. A first model takes into account the unsteady evolution of the centerline velocity, while the second model also includes the time variation of the characteristics of the boundary layer at the exit plane of the vortex generator. The models are tested in axisymmetric direct numerical simulations of vortex rings. As distinguished from classical SDV model, the new models allow to accurately reproduce the characteristics of the flow. In particular, the time evolution of the total circulation is in good agreement with experimental results and previous numerical simulations including the vortex generator. The second model also provides a more realistic time evolution of the vortex ring circulation. Using the classical slug-model and the new correction for the centerline velocity, we finally derive a new and accurate analytical expression for the total circulation of the flow.     

Instrumental analysis and molecular modelling of inclusion complexes containing artesunate

Journal of Thermal Analysis and Calorimetry - The following work experimentally and numerically investigated the thermal performance of a hybrid nanofluid, prepared by decorating a nanostructured...     

Polysaccharide-Based Drug Delivery Systems for the Treatment of Periodontitis

Periodontal diseases are worldwide health problems that negatively affect the lifestyle of many people. The long-term effect of the classical treatments, including the mechanical removal of bacterial plaque, is not effective enough, causing the scientific world to find other alternatives. Polymer–drug systems, which have different forms of presentation, chosen depending on the nature of the disease, the mode of administration, the type of polymer used, etc., have become very promising. Hydrogels, for example (in the form of films, micro-/nanoparticles, implants, inserts, etc.), contain the drug included, encapsulated, or adsorbed on the surface. Biologically active compounds can also be associated directly with the polymer chains by covalent or ionic binding (polymer–drug conjugates). Not just any polymer can be used as a support for drug combination due to the constraints imposed by the fact that the system works inside the body. Biopolymers, especially polysaccharides and their derivatives and to a lesser extent proteins, are preferred for this purpose. This paper aims to review in detail the biopolymer–drug systems that have emerged in the last decade as alternatives to the classical treatment of periodontal disease.     

Infrared technique for simultaneous determination of temperature and emissivity

This paper presents, in the context of materials dynamic behaviour study, a method for simultaneous measurement of the temperature and emissivity of a solid’s surface, by the use of infrared radiation. In contrast to existing methods, this method has no need for a pre-measurement of the surface emissivity. The emissivity and the temperature are measured simultaneously, by detecting the variations of emitted radiation and infrared radiation reflecting on the surface, at two different spectral zones. In this way, the accuracy of the measured temperature is greatly improved in cases were the surface optical properties vary during the measurement. Several experiments were carried out in order to complete the theoretical foundation of the method and to outline its accuracy and some of its limitations. There are various industrial applications of this method, for example the control of the temperature of the mechanical parts during work machining. One of them may be the measurement of the temperature of a sample during mechanical testing. An application of the method is proposed, that is easy to employ with non-sophisticated infrared and optical components. The results confirm the accuracy of the proposed method with an order of 3% of precision for temperature determination.