Practice effects on two memory retrievals from a single cue.

The effects of practice on 2 retrievals from a single cue were investigated. In Experiment 1, participants were given extended single-task practice and were then tested on a dual memory retrieval task. Performance was consistent with a sequential retrieval model proposed by T. C. Rickard and H. Pashler (2003). In Experiment 2, participants practiced both single- and dual-retrieval tasks extensively. Initially, data from all participants indicated sequential retrieval. However, participants who grouped the 2 response outputs were eventually able to perform the dual task with a latency that approached the prediction of a parallel race model. Models that assume a transition from sequential to parallel retrieval with practice, along with other models that assume an immutable retrieval bottleneck at all practice levels, are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simplified sol-gel processing method for amorphous TiO x Memristors

The memristor, a two-terminal memory device with units of resistance, has continued to gain momentum as simpler and more versatile memristive devices are d     

Experimental investigation of the heat exchange to a compartmentalized plug flow

A two-phase (air–water), tubular counterflow heat exchanger was developed for industrial unitary process applications to realize an active heat transfer control. A controlled train of air plugs was injected in a stratified smooth water flow to yield a compartmentalized, continuous two-phase flow whose stability was carefully monitored. Related Nusselt numbers were evaluated for single- and two-phase flows, at the same flow regimes. This comparison shows how the traveling, controlled air plug “turbulators” allowed for a large heat transfer rate increase, for all observed heating rates and phase velocity ratios. The analysis includes a comparison with the available literature correlations, and the efficiency of the adopted heat transfer control is finally inferred while a range of flow regimes is identified which optimizes the heat exchange.     

An evolutionary algorithm for fractal coding of binary images

An evolutionary algorithm is used to search for iterated function systems (IFS) that can encode black and white images. As the number of maps of the IFS that encodes an image cannot be known in advance, a variable-length genotype is used to represent candidate solutions, Accordingly, feasibility conditions of the maps are introduced, and special genetic operators that maintain and control their feasibility are defined, In addition, several similarity measures are used to define different fitness functions for experimentation. The performance of the proposed methods is tested on a set of binary images, and experimental results are reported     

A Framework for Coupled Simulations of Robots and Spiking Neuronal Networks

Bio-inspired robots still rely on classic robot control although advances in neurophysiology allow adaptation to control as well. However, the connection of a robot to spiking neuronal networks needs adjustments for each purpose and requires frequent adaptation during an iterative development. Existing approaches cannot bridge the gap between robotics and neuroscience or do not account for frequent adaptations. The contribution of this paper is an architecture and domain-specific language (DSL) for connecting robots to spiking neuronal networks for iterative testing in simulations, allowing neuroscientists to abstract from implementation details. The framework is implemented in a web-based platform. We validate the applicability of our approach with a case study based on image processing for controlling a four-wheeled robot in an experiment setting inspired by Braitenberg vehicles.     

Erosion behavior of Y2O3 in fluorine-based etching plasmas: Orientation dependency and reaction layer formation

Even though advanced ceramics are widely applied as consumables in semiconductor etching processes, the erosion mechanisms and connected surface phenomena are not fully understood. Through the interaction with reactive species and ion bombardment during the plasma exposure, oxide ceramic materials like Y₂O₃ are eroded by a physicochemical mechanism. In this study, fundamental phenomena of surface-plasma interactions were investigated directly at the surface as well as in the near-surface region after exposure to fluorine-based etching plasmas. A straightforward re-localization technique was used to investigate the microstructural features before and after the plasma exposure for up to 2 hours. Electron microscopy methods (scanning electron microscopy, electron backscatter diffraction) were coupled with atomic force microscopy, secondary ion mass spectroscopy, and transmission electron microscopy to study the surface topography and the corresponding reaction layer. Direct correlation of the microstructure before plasma exposure with the surface topography reveals a novel orientation-dependent erosion mechanism that forms plateau-like structures. Furthermore, the in-depth analysis of the near-surface area highlights the influence of the applied bias voltage on the physical damage and chemical gradient formation due to plasma exposure. The combined investigation of surface morphology and near-surface properties reveals new fundamental aspects of the erosion behavior of polycrystalline yttria in CF₄-based etching plasmas.     

Bacteria enclosure between silica-coated membranes for the degradation of organic compounds in contaminated water

A non-conventional technique is proposed for the enclosure of either pure bacterial cultures or entire biocoenoses, for a possible utilization in the treatment of contaminated water. Biological components have been enclosed between polyester membranes coated by silica films consisting of: (a) SiO2 and nitrocellulose, (b) SiO2, ZnS crystals and nitrocellulose, (c) SiO2, TiO2 crystals and nitrocellulose, (d) SiO2, ZnS and TiO2 crystals and nitrocellulose. Morphological, structural and mechanical features of membranes were investigated by means of optical and electron microscopy, mercury porosimetry and wear resistance tests. Degradation kinetics have been finally studied by dipping the entrapped biomass into aqueous solutions of three different model organic compounds (alpha-d-glucose, ethyl alcohol and peptone). Results are very promising: in fact, no metabolic inhibition mechanisms of microorganisms have been evidenced. The porosity of the system allows mass transfer through the membranes, hence bacteria can grow and degrade pollutants. Besides, by this system, cells are constrained, avoiding they to spread across the retainment scaffold.     

Synthesis of Acetonides from Epoxides Catalyzed by Erbium(III) Triflate

Epoxides dissolved in acetone can be converted almost quantitatively in acetonides in the presence of catalytic amounts of erbium(III) triflate. The procedure can be usefully applied to other substrates and can be extended to other ketones.     

Effect of Microwave Processing on the Crystallization and Energy Density of BaO‐Na2O‐Nb2O5‐SiO2‐B2O3 Glass‐Ceramics

Barium sodium niobate (BNN) glass‐ceramics were successfully synthesized through a controlled crystallization method, using both a conventional and a microwave hybrid heating process. The dielectric properties of glass‐ceramics devitrified at different temperatures and conditions were measured. It was found that the dielectric constant increased with higher crystallization temperature, from 750°C to 1000°C, and that growth of the crystalline phase above 900°C was essential to enhancing the relative permittivity and overall energy storage properties of the material. The highest energy storage was found for materials crystallized conventionally at 1000°C with a discharge energy density of 0.13 J/cm³ at a maximum field of 100 kV/cm. Rapid microwave heating was found to not give significant enhancement in dielectric properties, and coarsening of the ferroelectric crystals was found to be critical for higher energy storage.