SHS of high-purity MAX compounds in the Ti-Al-C system

During the synthesis of MAX phases using combustion synthesis (or Self-Propagating High-temperature Synthesis), the main drawback is the presence of binary phases, and especially the simple MX carbide, when X = C. Our experiments were designed in order to check whether the cooling rate of the sample immediately after synthesis might play a key role for obtaining samples with low-level carbide contents. In the best conditions, a TiC content of about 2% only has been observed. A systematic study on the direct effect of the cooling rate on the final composition has then been conducted, and confirms that high cooling rates allow the synthesis of high-purity MAX phases in the Ti-Al-C system.      

The effects of volume and speed of injection in peribulbar anaesthesia

Therapy of detrusor hyperactivity with anticholinergic agents often is followed by adverse drug reactions. Intravesical application may be an interesting alternative. A randomised, single-blind, placebo-controlled, mono-centre clinical trial was carried out in 84 patients with urgency or urge incontinence. Due to intravesical administration of oxybutynin (CAS 5633-20-5) (n = 21) and trospium chloride (CAS 10405-02-4) (n = 21), respectively, a significant increase in maximum bladder capacity and decrease of detrusor pressure accompanied by an increase of residual urine were found in comparison to placebo in urodynamical investigations. Improvement of uninhibited bladder contractions occurred leading to higher filling volume. Under verapamil (CAS 152-11-4) (n = 21) no marked changes in the efficacy variables were found compared with placebo. All patients completed the study and were assessed with regard to efficacy and safety. No adverse events or marked changes in the vital signs were reported. The immediate onset of effect and the lack of adverse drug reactions suggest that treatment with topical oxybutynin or trospium chloride is an effective alternative in patients with intolerable side effects when orally treated. In addition, intravesical administration may be indicated in patients with bladder spasms due to indwelling catheter or in order to increase bladder capacity before percutaneous cystostomy.     

Redesigning an FKBP-ligand interface to generate chemical dimerizers with novel specificity

FKBP ligand homodimers can be used to activate signaling events inside cells and animals that have been engineered to express fusions between appropriate signaling domains and FKBP. However, use of these dimerizers in vivo is potentially limited by ligand binding to endogenous FKBP. We have designed ligands that bind specifically to a mutated FKBP over the wild-type protein by remodeling an FKBP-ligand interface to introduce a specificity binding pocket. A compound bearing an ethyl substituent in place of a carbonyl group exhibited sub-nanomolar affinity and 1,000-fold selectivity for a mutant FKBP with a compensating truncation of a phenylalanine residue. Structural and functional analysis of the new pocket showed that recognition is surprisingly relaxed, with the modified ligand only partially filling the engineered cavity. We incorporated the specificity pocket into a fusion protein containing FKBP and the intracellular domain of the Fas receptor. Cells expressing this modified chimeric protein potently underwent apoptosis in response to AP1903, a homodimer of the modified ligand, both in culture and when implanted into mice. Remodeled dimerizers such as AP1903 are ideal reagents for controlling the activities of cells that have been modified by gene therapy procedures, without interference from endogenous FKBP.     

A new topology of hybrid synchronous machine

Permanent-magnet synchronous machines are able to operate over a wide range of speeds at constant power through the use of control laws allowing for flux weakening. Generally, this is performed by applying a strong demagnetizing current in the d axis, yet such an approach involves the risk of irreversible magnet demagnetization and, consequently, a reduction in machine performance. This paper presents a novel structure for a hybrid synchronous machine. The authors' solution provides good flux weakening without introducing the risk of magnet demagnetization. In order to explain the structure's operating principle, they apply a model with a single elementary design; electromotive force measurements are then presented to demonstrate the possibilities of flux weakening, along with a series of simulations to show the contribution of hybrid excitation     

Hydrodynamical modelling and multidimensional approximation of estuarian river flows

We propose a new approach for deriving hydrodynamical models, within the framework of mixed variational formulations. We thus obtain a 2D-horizontal model, as well as a 2D-vertical one and a 1D model taking into account the geometry of the river. We briefly study here the 2D-vertical and the 1D models and we propose (after time discretization) low-order conforming finite element approximations. All the variational problems are well-posed. We justify next a posteriori estimators between the models, which allow us to couple them. Numerical tests, achieved with a realistic bathymetry, are next presented.     

Contribution to the development of a method of maple sap soft drink stabilization by electro-activation technology

Electro-activation (EA) of a maple sap/syrup beverage was studied. The purpose of the study was to assess the product parameters, such as pH, ORP, transmittance and degree Brix, while minimizing energy consumption. The experiments were conducted using three different configurations of the reactor that differed by the position of the anion (AEM) and cation (CEM) exchange membrane relative to the electrodes as well as the nature of the electrolyte (NaCl vs. Na₂CO₃) in the central cell of the reactor. The results showed that the type of configuration, the electric current and the temperature influenced the parameters of the electro-activated beverage. At 23 °C, the beverage was acidified to pH 3.89 with a Redox potential (ORP) of 417.33 mV. At 55 °C and 150 mA, the minimum pH of 3.78 and an ORP of 329.67 mV were obtained. The electric resistance of the electro-activation reactor (EAR) decreased during electro-activation, indicating a gain of energy efficiency corresponding to an electric resistance of 266.76 Ω. Moreover, the reactor configuration and electric current affected the presence or absence of a fouling of the ion exchange membrane at the anodic side. The beverages' transmittance increased slightly during EA without any effect on the degree Brix.     

Optical amplification of diffraction-free beams by photorefractive two-wave mixing and its application to laser Doppler velocimetry

The Fraunhofer diffraction pattern of a narrow annular slit is recorded holographically to generate a beam that approximates a diffraction-free Bessel beam. The experimental limitations resulting from the annular-slit parameters such as the opening width and the transmission coefficient are discussed. The reconstructed Bessel beam is amplified by two-wave mixing in a photorefractive crystal. Thus the efficient conversion of a relatively large beam with a constant (or Gaussian) intensity distribution into a nondiffracting beam is achieved entirely by direct physical interference. We show that diffraction-free beams reproduced and amplified in this way can be applied to the measurement of the velocity of small objects by the use of the laser Doppler technique. In addition, the advantages of Bessel beams, especially in measuring the velocity of solids, are discussed.     

A Review on Materials Derived from Polystyrene and Different Types of Nanoparticles

Nanoparticles are divided into different categories depending upon their significance in current research. The principle types of nanoparticles are inorganic, organic, and hybrid nanoparticles. Fabrication routes to nanoparticles play an important role to obtain the desired features. Therefore, methods and challenges in preparation of nanoparticles have been discussed. Taking polystyrene into consideration, materials derived from polystyrene and nanoparticles have also been overviewed. Nanoparticle-based nanostructures have been used in numerous technological areas, ranging from catalysis and coatings to biomedicine and optoelectronics, depending upon the final properties. Hence, recent trends and future outlook of nanoparticle-derived materials have been discussed at the end.