Stimulus-responsive fluidic dispersions of rod shaped liquid crystal polymer colloids

Electrically responsive liquid crystal polymer nanorods were fabricated by template synthesis. Liquid crystal monomers are templated by alumina membranes. Molecular ordering of the liquid crystal molecules resulted from the confinement in the sub-micron channels and this ordering can be captured permanently through photo-polymerization. Template removal and sonication result in individual rods that can be reoriented by applied electrical and magnetic fields. Such anisotropic particles have significant potential applications in electro-rheological fluids and in active mixing in microfluidic channels.     

Intelligent discovery of the capabilities of reconfiguration options in a cognitive wireless B3G context

Beyond 3G (B3G) wireless connectivity can efficiently be realized by exploiting cognitive networking concepts. Cognitive systems dynamically reconfigure the radio access technologies and the spectrum they use, based on experience, in order to adapt to the changing environment conditions. However, dynamic reconfiguration decisions call for robust discovery, i.e., radio-scene analysis and channel identification schemes. This paper intends to contribute in the areas of radio-scene analysis and channel identification: first, by providing an overview of interference estimation methods, and explaining how capacity estimations can be derived based on the measured interference levels; second, by specifying the information flow for the radio-scene analysis process of a cognitive radio system; and third, by enhancing the above with a learning system, which is essential for obtaining a truly cognitive process. The proposed approach lies in the introduction of a robust probabilistic model for optimal prediction of the capabilities of alternative configurations, in terms of capacity.     

Preparation and nonlinear optical response of novel palladium-containing micellar nanohybrids

The synthesis and characterization of novel micellar nanohybrids with controllable sizes consisting of palladium nanosized core and covered by well-defined poly(lauryl methacrylate)-block-poly(2-(acetoacetoxy)ethyl methacrylate) (pLauMA-b-pAEMA) diblock copolymers are reported. Their nonlinear optical (NLO) response (i.e. nonlinear refraction and absorption and the third-order susceptibility χ⁽³⁾) is also studied under 35 ps laser excitation both in the visible and in the infrared and found to be insensitive to the size of the micelles while it was found to be greatly affected by the molar fraction of the AEMA block. To the best of our knowledge it is the first time that such Pd micellar nanohybrids are synthesized and investigated towards their NLO properties. The magnitude of the nonlinear optical response of these nanohybrids renders them promising candidates for potential optoelectronic applications.     

Historical Evolution of the Transient Hot-Wire Technique

The paper attempts to describe the historical evolution of the transient hot-wire technique, employed today for the measurement of the thermal conductivity of fluids and solids over a wide range of conditions. Starting from the first experiments with heated wires in 1780 during the discussions of whether gases could conduct heat, it guides the reader through typical designs of cells and bridges, software employed and theory developed, to the modern applications. The paper is concluded with a discussion of the areas of application where problems still exist, and a glimpse of the technique’s future.     

Theoretical and experimental investigation of pulsed laser grooving process

A theoretical model has been developed for simulating the laser grooving process. It takes into account the interaction among subsequent pulses, the required time for the melting temperature to be reached and the subsequent removal of a finite volume of material during each laser pulse. The model predicts the maximum groove depth that can be achieved for a specified set of process parameters, such as laser power, pulsing frequency, and scanning velocity. The theoretical predictions have been experimentally tested with a medium-power laser beam.     

Testing and applications of a process model in the metallurgical production practice of ferronickel from laterites

A mathematical model of the electro-reduction furnace process (ERF process), for the production of ferronickel from laterite ores, has been tested at Larco's metallurgical plant at Larymna Greece. The theoretical predictions for the progress of the nickel reduction have been compared with the operational results. The tests were carried out in the ERF no. 2 of Larco's plant. The influence of the main process variables on the nickel recovery and nickel losses in the ERF slags have been investigated in conjunction with the variation of the analysis of the feed and the nickel content of the metal bath. The further application of the model to the metallurgical practice is discussed. According to the predictions of the model the further development of the process in the direction of the production of low-nickel ferronickel (Ni < 15%) is analyzed. The advantages of the production of low-nickel ferronickel are presented and the possibility of its straight conversion to nickel-bearing steel-grades is discussed.     

Lignite industry in Greece within a world context: Mining,energy supply and environment

Today coal covers 38% of global production and roughly 30% of the EU-25 power output.     

Reliability assessment of the rotation algorithm for earthquake damage estimation

A rotation algorithm was developed that computes the slope of permanently deformed columns subjected to earthquake ground motion using micro-electro-mechanical system accelerometers. Previous studies by the authors have shown that the algorithm can provide estimates of the residual displacement in the column, and thus the story drift can be evaluated. The algorithm was validated through applications to columns that deflect in single and double curvature. Information from tests on such columns conducted at various laboratories was used to conduct the study. The optimal number of sensors and their placement on the test columns were determined through a series of numerical analyses. The accuracy of the rotation and displacement estimates is assessed under the assumptions of zero-noise sensors and perfect measurements. In this paper, the effect of measurement error and sensor noise on the predicted rotations and corresponding deformations is studied in order to provide bounds on the accuracy of the rotation algorithm and on the allowable sensor noise. The same test columns are used for the purposes of these analyses.     

Hydrolytic Depolymerization of PET in a Microwave Reactor

Recycling of PET was examined using hydrolytic depolymerization in an alkaline solution under microwave irradiation. The reaction was carried out in a sealed microwave reactor in which the pressure and temperature were controlled and recorded. The main products were the monomers TPA and EG. The effect of reaction temperature, time, amount of PET and alkaline concentration on the degree of PET depolymerization and TPA recovery was investigated. Microwave irradiation was found to reduce the time needed to achieve a specific degradation of PET significantly, with almost complete depolymerization occurring in 30 min at 180 °C and only 46 W of microwave power. Using a phase transfer catalyst (TOMAB) resulted in the same amount of unreacted PET but at significantly lower depolymerization temperatures.

     

Laser Melting of Spark Plasma-Sintered Zirconium Carbide: Thermophysical Properties of a Generation IV Very High-Temperature Reactor Material

Melting temperatures of zirconium carbide were investigated in validating a novel thermal analysis technique for refractory materials. Commercial ZrC_0.96 powder was densified by spark plasma sintering to >96% relative density after 6–30 min at 2173–2453 K under 40–100 MPa. Sintered ceramics were heated to >4000 K via pulsed laser heating. Mean values for solidus and liquidus transitions were 3451 and 3608 K, respectively, in fair agreement with the present phase diagram. Postmelting analysis revealed dendritic microstructure and composition consistent with single-phase ZrC. Subsurface gas porosity and ZrC–C eutectic indicate complex processes occurring during melting and freezing.