Information content of data measured with a multiple-field-of-view lidar

Lidars with multiple fields of view (MFOVs) are promising tools for gaining information on cloud particle size. We perform a study of the information content of MFOV lidar data with the use of eigenvalue analysis. The approach we have developed permits an understanding of the main features of MFOV lidars and provides a way to relate the accuracy of particle size estimation with the measurement uncertainty and the scattering geometry such as the cloud-base height and the lidar sounding depth. Second-order scattering computations are performed for an extended range of particle sizes and for a wide range of lidar fields of view (FOVs). The results obtained allow us to specify the areas of possible applications of these lidars in cloud studies. Comparison of results obtained with polarized and cross-polarized scattered components demonstrate that the cross-polarized signal should provide a more stable retrieval and is preferable when double scattering is highly dominant. Our analysis allows for the estimation of the optimal number of FOVs in the system and their angular distribution, so this work can be a useful tool for practical MFOV lidar design.     

Field-directed self-assembly with locking nanoparticles

A reversible locking mechanism is established for the generation of anisotropic nanostructures by a magnetic field pulse in liquid matrices by balancing the thermal energy, short-range attractive and long-range repulsive forces, and dipole-dipole interactions using a specially tailored polymer shell of nanoparticles. The locking mechanism is used to precisely regulate the dimensions of self-assembled magnetic nanoparticle chains and to generate and disintegrate three-dimensional (3D) nanostructured materials in solvents and polymers.     

Inside Front Cover: Superhydrophobic Surfaces Generated from Water‐Borne Dispersions of Hierarchically Assembled Nanoparticles Coated with a Reversibly Switchable Shell (Adv. Mater. 1/2008)

On p. 200, Sergiy Minko and co‐workers report on the fabrication of a superhydrophobic coating from aqueous dispersions of hybrid responsive nanoparticles with no application of surfactants and organic solvents. A suspension of the particles forms a textured hydrophilic coating upon casting. Heating above the glass transition temperature of polystyrene, or treatment in acidic water, resulted in backward and forward switching between the superhydrophobic and the hydrophilic material, respectively.     

Synthesis, structure, thermal and mechanical properties of nanocomposites based on linear polymers and layered silicates modified by polymeric quaternary ammonium salts (ionenes)

Polymer–clay composites has been prepared by melt blending an organo-bentonite with linear polymers (polyamide, polysterene and polypropylene) in a disk-screw extruder. In first time organo-clay was prepared by surface treatment of Na-forms bentonite with polymeric quaternary ammonium salts (PQAS). XRD indicated that organo-bentonite layers were exfoliated and dispersed into polyamide and polystyrene. Addition of 2 wt% organo-bentonites (optimal concentration) to polyamide increased tensile strength by 53% and Sharpy impact by 140%. With the incorporation of 2 wt% organo-bentonites (optimal concentration) into polystyrene the tensile strength increased to 28% and the Sharpy impact increased to 25%. For polypropylyne–organo-bentonites composites we did not observe delamination of layered structure, and as result absence of reinforcements. TGA showed that the polyamide and polystyrene nanocomposites have higher decomposition temperature in comparison with the original polymers.     

Cache-Integrated Network Interfaces: Flexible On-Chip Communication and Synchronization for Large-Scale CMPs

Per-core scratchpad memories (or local stores) allow direct inter-core communication, with latency and energy advantages over coherent cache-based communication, especially as CMP architectures become more distributed. We have designed cache-integrated network interfaces, appropriate for scalable multicores, that combine the best of two worlds – the flexibility of caches and the efficiency of scratchpad memories: on-chip SRAM is configurably shared among caching, scratchpad, and virtualized network interface (NI) functions. This paper presents our architecture, which provides local and remote scratchpad access, to either individual words or multiword blocks through RDMA copy. Furthermore, we introduce event responses, as a technique that enables software configurable communication and synchronization primitives. We present three event response mechanisms that expose NI functionality to software, for multiword transfer initiation, completion notifications for software selected sets of arbitrary size transfers, and multi-party synchronization queues. We implemented these mechanisms in a four-core FPGA prototype, and measure the logic overhead over a cache-only design for basic NI functionality to be less than 20%. We also evaluate the on-chip communication performance on the prototype, as well as the performance of synchronization functions with simulation of CMPs with up to 128 cores. We demonstrate efficient synchronization, low-overhead communication, and amortized-overhead bulk transfers, which allow parallelization gains for fine-grain tasks, and efficient exploitation of the hardware bandwidth.     

Adsorption of zinc by activated carbons prepared from solvent extracted olive pulp

Activated carbons have been prepared by a two-step physical activation with steam at different burn-off levels to study the porosity development and its effect in zinc adsorption from aqueous solutions. The main material used was the residual from the extraction with solvent of the kernel-oil [solvent extracted olive pulp (SEOP)]. Olive, apricot and peach stone have been also used as different precursors. The products were characterized by N2 at 77K adsorption, Hg porosimetry and iodine number determination. The influence of surface complexes and pH has been investigated in an attempt to elucidate the adsorption phenomena. The effect of different treatments [demineralization with H2SO4 and oxidation with (NH4)2S2O8] was also evaluated for the adsorption of zinc species.Both basic and acidic carbons, originated from SEOP, show remarkable adsorption ability at solution pH=7. Their adsorption ability mainly depends on the content and nature of functional surface groups, the ash content of the precursors and the pH of the solution. These activated carbons were proved to be efficient adsorbents for the removal of water pollutants and contaminants.     

A Listening Keyboard for Users with Motor Impairments—A Usability Study

Computer users with motor impairments find it difficult and, in many cases, impossible to access PC functionality through the physical keyboard-and-mouse interface. Studies show that even able-bodied users experience similar difficulties when interacting with mobile devices; this is due to the reduced size/usability of the input interfaces. Advances in speech recognition have made it possible to design speech interfaces for alphanumeric data entry and indirect manipulation (cursor control). Although several related commercial applications exist, such systems do not provide a complete solution for arbitrary keyboard and mouse access, such as the access needed for, say, typing, compiling, and executing a C++ program.We carried out a usability study to support the development of a speech user interface for arbitrary keyboard access and mouse control. The study showed that speech interaction with an ideal listening keyboard is better for users with motor impairments than handstick, in terms of task completion time (37% better), typing rate (74% better), and error rates (63% better). We believe that these results apply to both permanent and task-induced motor impairments. In particular, a follow-up experiment showed that handstick approximates conventional modes of alphanumeric input available on mobile devices (e.g., PDAs, cellular phones, and personal organizers). These modes of input include miniaturized keyboards, stylus soft keyboards, cellular phone numberpads, and handwriting recognition software. This result suggests that a listening keyboard would be an effective mode for alphanumeric input on future mobile devices.This study contributed to the development of SUITEKeys—a speech user interface for arbitrary keyboard and mouse access available for MS platforms as freeware.     

Information discovery across multiple streams

In this paper we address the issue of continuous keyword queries on multiple textual streams and explore techniques for extracting useful information from them. The paper represents, to our best knowledge, the first approach that performs keyword search on a multiplicity of textual streams. The scenario that we consider is quite intuitive; let’s assume that a research or financial analyst is searching for information on a topic, continuously polling data from multiple (and possibly heterogeneous) text streams, such as RSS feeds, blogs, etc. The topic of interest can be described with the aid of several keywords. Current filtering approaches would just identify single text streams containing some of the keywords. However, it would be more flexible and powerful to search across multiple streams, which may collectively answer the analyst’s question. We present such model that takes in consideration the continuous flow of text in streams and uses efficient pipelined algorithms such that results are output as soon as they are available. The proposed model is evaluated analytically and experimentally, where the Enron dataset and a variety of blog datasets are used for our experiments.