Paper Reports Recent Advances Research Articles

Layered Viscoelastic Analysis with Moving Loads of Low-Volume Roadway Pavement Response

Low-volume roads (LVRs) are typically not expected to withstand large amounts of traffic, consequently they have relatively thin pavement structures. However situations can occur when traffic loading rapidly increases, resulting in rapid structural deterioration of the pavement. Examples include resource exploration and production, new industrial facilities, and military operations. Improved evaluation procedures, including computation of pavement structural responses, are needed to accommodate these scenarios. This paper reports recent advances in methods for computing the structural response of LVRs that incorporate viscoelastic asphalt material behavior and accommodate moving loads. Application of layered elastic analysis, using a Hankel transform with numerical integration methods, is popular in several mechanistic-empirical pavement design procedures. This paper describes an application of the collocation method for approximating the creep compliance and viscoelastic solution, which removes the necessity for approximating the Laplace transform inversion. This was coupled with Boltzmann’s superposition principle for moving loads. Comparisons showed that the proposed approximate method matched well with the viscoelastic solution, and with the full-scale instrumented test data of highway pavements. The measured near surface response of a thin LVR test pavement subjected to military truck loads was then modeled to determine the suitability of the approach for LVR. The modeled results for asphalt strain and vertical pressure in the granular layers showed generally good agreement with the measured instrumentation data. The developed structural response model provided a more realistic simulation of flexible pavement viscoelastic material behavior and accommodation of moving loads with similar computational speed to a conventional layered elastic approach.

Roadmap of ellipsometric characterization of plasmonic nanoparticles

This paper reports recent advances in ellipsometric characterization of silver and gold nanoparticles (NPs). Three systems are investigated: films composed of Au NPs distributed in shape, films with a gradient of concentration of Ag NPs, and colloidal suspensions composed of Au NP chains. The authors show that ellipsometry is highly sensitive to the plasmon resonance of NPs. This later can be used as an efficient probe of the NP morphology. The ellipsometric results are systematically compared to those that are obtained by transmission electron microscopy. The authors demonstrate that quantitative insights such as the shape distribution, the concentration, and the organization of NPs can be extracted from ellipsometric spectra.

Biologically-motivated system identification: application to microbial growth modeling.

This paper presents a new method for identification of system models that are linear in parametric structure, but arbitrarily nonlinear in signal operations. The strategy blends traditional system identification methods with three modeling strategies that are not commonly employed in signal processing: linear-time-invariant-in-parameters models, set-based parameter identification, and evolutionary selection of the model structure. This paper reports recent advances in the theoretical foundation of the methods, then focuses on the operation and performance of the approach, particularly the evolutionary model determination. The method is applied to the modeling of microbial growth by Monod Kinetics.

High precision batch mode micro-electro-discharge machining of metal alloys using DRIE silicon as a cutting tool

This paper reports recent advances in batch mode micro-electro-discharge machining (µEDM) for high precision micromachining of metal alloys such as stainless steel. High-aspect-ratio silicon microstructures with fine feature sizes formed by deep reactive ion etching are used as cutting tools. To machine workpiece features with widths ≤10 µm, a silicon dioxide coating is necessary to passivate the sidewalls of the silicon tools from spurious discharges. In the machined workpieces, a minimum feature size of ≈7 µm and an aspect ratio up to 3.2 are demonstrated by the batch mode µEDM of stainless steel 304 and titanium (Grade 1) substrates. Machining rates up to ≈5 µm min−1 in feature depth are achieved in batch mode micromachining of typical microfluidic structures, including arrays of channels and cavities of different sizes. The machined features are uniform across a die-scale area of 5 × 5 mm2. Other machining characteristics are also discussed.

A hearing-inspired approach for distant-microphone speech recognition in the presence of multiple sources

This paper addresses the problem of speech recognition in reverberant multisource noise conditions using distant binaural microphones. Our scheme employs a two-stage fragment decoding approach inspired by Bregman's account of auditory scene analysis, in which innate primitive grouping ‘rules’ are balanced by the role of learnt schema-driven processes. First, the acoustic mixture is split into local time-frequency fragments of individual sound sources using signal-level primitive grouping cues. Second, statistical models are employed to select fragments belonging to the sound source of interest, and the hypothesis-driven stage simultaneously searches for the most probable speech/background segmentation and the corresponding acoustic model state sequence. The paper reports recent advances in combining adaptive noise floor modelling and binaural localisation cues within this framework. By integrating signal-level grouping cues with acoustic models of the target sound source in a probabilistic framework, the system is able to simultaneously separate and recognise the sound of interest from the mixture, and derive significant recognition performance benefits from different grouping cue estimates despite their inherent unreliability in noisy conditions. Finally, the paper will show that missing data imputation can be applied via fragment decoding to allow reconstruction of a clean spectrogram that can be further processed and used as input to conventional ASR systems. The best performing system achieves an average keyword recognition accuracy of 85.83% on the PASCAL CHiME Challenge task.

Multivariate Data Assimilation in the Tropics by Using Equatorial Waves

This paper reports recent advances in understanding of dynamical aspects of the tropical data assimilation. In contrast with the mid-latitudes, there is no a well-defined approach for the tropical data assimilation in numerical weather prediction (NWP) community which has traditionally been concentrated on the mid-latitude analysis problem. In particular, the impact of the equatorial Rossby, inertio-gravity, and mixed Rossby-gravity waves on the tropical forecast-error covariances is difficult to quantify. Various tropical waves are characterized by different couplings between the mass field and the wind field. The average mixture of these waves, built into the background-error covariance matrix for data assimilation provides analysis increments which appear nearly univariate even though they result from the advanced multivariate assimilation methodology. This applies to both dry and moist idealized tropical systems as well as to a 4D-Var NWP assimilation system.

Noise attenuation by phononic crystals made of recycled materials.

This paper reports recent advances on the topic of sound attenuation of airborne sound by noise barriers based on 2-D phononic crystals (PnCs). We consider here the case in which the PnC building units are made of rubber crumb, a porous absorptive material obtained by recycling used tires. The resulting sound attenuation is obtained by a combination of two effects: Bragg reflection by the periodic distribution of cylindrical scatterers and sound absorption by the rubber crumb. Several barrier samples consisting of three rows of scatterers have been fabricated and characterized. Their attenuation performance is compared with that of equivalent samples built with only rigid cylinders. Transmittance and reflectance spectra have been independently measured to obtain the absorption properties of each sample. The results indicate that samples made of rubber crumb show broadband sound attenuation in comparison with those fabricated with no absorptive material. Prototypes of actual size for traffic noise attenuation will also be reported and discussed. Numerical simulations based on the multiple scattering method are in agreement with the experimental data. [Work supported by ONR and by MICIIN of Spain.]

Paper Actuators Made with Cellulose and Hybrid Materials

Recently, cellulose has been re-discovered as a smart material that can be used as sensor and actuator materials, which is termed electro-active paper (EAPap). This paper reports recent advances in paper actuators made with cellulose and hybrid materials such as multi-walled carbon nanotubes, conducting polymers and ionic liquids. Two distinct actuator principles in EAPap actuators are demonstrated: piezoelectric effect and ion migration effect in cellulose. Piezoelectricity of cellulose EAPap is quite comparable with other piezoelectric polymers. But, it is biodegradable, biocompatible, mechanically strong and thermally stable. To enhance ion migration effect in the cellulose, polypyrrole conducting polymer and ionic liquids were nanocoated on the cellulose film. This hybrid cellulose EAPap nanocomposite exhibits durable bending actuation in an ambient humidity and temperature condition. Fabrication, characteristics and performance of the cellulose EAPap and its hybrid EAPap materials are illustrated. Also, its possibility for remotely microwave-driven paper actuator is demonstrated.

An NTD germanium-based microcalorimeter with 3.1 eV energy resolution at 6 keV

This paper reports recent advances in our microcalorimeter spectrometer that result in an energy resolution of 3.1 eV FWHM for 6 keV X-rays. We have developed a detailed model that indicates that further minor improvements will realize 2 eV FWHM at 6 keV and well under 2 eV at 1 keV. The results demonstrate the value of the microcalorimeter for many applications where a premium exists for very fine resolution in the 0.2–10 keV energy band.

Les collagènes associés aux membranes basales et leurs matricryptines

The superfamily of collagens is comprised of 27 members (reviewed by Myllyharju & Kivirikko, 2004; Ricard-Blum & Ruggiero, 2005; Ricard-Blum et al., 2005), which are classified into several subgroups according to their structural features and supramolecular assemblies. Fibrillar collagens and FACITS (Fibril-Associated Collagens with Interrupted Triple helix) are described in the paper by Ruggiero et al. in this issue. Our paper reports recent advances on collagens associated to basement membranes. It focuses on the multiplexin family (including collagens XV and XVIII) and on membrane collagens present in skin, namely collagens XIII and XVII. The mechanisms leading to the shedding of their ectodomain from cell membrane and the biological roles of their shedded domains are discussed. The last part of the paper is devoted to several fragments of basement membrane collagens, called matricryptins or matrikins, and to their biological activities.

A Sweeping Mode Integrated Fingerprint Sensor With 256 Tactile Microbeams

This paper reports recent advances in the development of a tactile fingerprint sensor made by a CMOS compatible front side bulk micromachining technology. This device enables the measurement of a fingerprint by the way of a mechanical scanning principle of the finger roughness. While this sensing principle has shown good results on a first prototype of reduced width, we present here the design, fabrication and test of a new sensor. This sensor contains 256 pressure sensitive microbeams for a total length of 1.28 cm and is fully integrated with analog and mixed signal electronics. In this paper we will detail the general working principle of the tactile fingerprint sensor and the two prototypes that have been manufactured and tested with a special focus on the electronic architecture and the test results of the second prototype.

Ion beam application in genetic modification

People pay little attention to the interaction between low-energy ions and matter compared to that of high-energy ions. It is even more unusual to find studies of the interaction of low-energy ions and complicated organisms. The discovery of bioeffects induced by ion implantation has, however, opened a new branch in the field of ion beam applications in the life sciences. This paper reports recent advances in research on the role of low-energy ions in genetic modification.

Interaction between Low Energy Ions and the Complicated Organism

Low energy ions exist widely in natural world, but people pay a little attention on the interaction between low energy ions and matter, it is even more out of the question of studying on the relation of low energy ions and the complicated organism. The discovery of bioeffect induced by ion implantation has, however, opened a new branch in the field of ion beam application in life sciences. This paper reports recent advances in research on the role of low energy ions in chemical synthesis of the biomolecules and application in genetic modification.

Low Energy Implantation and Transient Enhanced Diffusion: Physical Mechanisms and Technology Implications

ABSTRACTLow energy implantation is currently the most promising option for shallow junction formation in the next generations of silicon CMOS technology. Of the dopants that have to be implanted, boron is the most problematic because of its low stopping power (large penetration depth) and its tendency to undergo transient enhanced diffusion and clustering during thermal activation. This paper reports recent advances in our understanding of low energy B implants in crystalline silicon. In general, satisfactory source-drain junction depths and sheet resistances are achievable down to 0.18 micron CMOS technology without the need for implantation of molecular species such as BF2. With the help of defect engineering it may be possible to reach smaller device dimensions. However, there are some major surprises in the physical mechanisms involved in implant profile formation, transient enhanced diffusion and electrical activation of these implants, which may influence further progress with this technology. Some initial attempts to understand and model these effects will be described.

A study on multiple photon-gated persistent spectral hole burning and photoproduct in a system of frequency-domain storage material

This paper reports recent advances in the study on multiple photon-gated spectral hole burning and its photoproduct in a system of Zn-tetrabenzoporphin-crotonic acid-phenoxy resin at liquid helium temperature. The influences of gating-light inducing hole-erasing and satellite holes causing hole-filling on the formation of multiple holes are analyzed. A spectrum of more than 100 multiple photon-gated spectral holes burnt over a whole absorption band is presented. The photoproduct after hole burning was also observed indicating the hole burning process to be donor-acceptor electron transfer reaction.

Developmental odontogenic cysts. An update1

This review paper reports recent advances in the subject of developmental odontogenic cysts, essentially those of the past decade, starting with reference to the new WHO classification (1). On keratocysts, the latest reported recurrence rates are assessed as are their mode of growth, immunocytochemistry, immunology, genetic studies, and work on specific keratocyst antigens. There is a critical account of the group of lesions which includes the gingival cyst of adults, lateral periodontal cyst, botryoid odontogenic cyst and glandular odontogenic cyst, and their possible relationship to one another. On dentigerous cysts, reference is made to the relationship between them and deciduous teeth, as well as to their immunocytochemistry and immunology. Recent work on the unicystic ameloblastomas, their classification and prognosis, is assessed, as is the calcifying odontogenic cyst and its relationship with solid odontogenic tumours.

Spatial Resolution and Data Addressing of Frequency Domain Optical Storage Materials in the Near IR Regime

This paper reports recent advances in the study of Frequency domain optical storage (FDOS) based on the photochemical hole-burning (PHB) method. New PHB systems are introduced which operate in the near IR regime and are suitable for the use of semiconductor lasers. Furthermore experiments to determine the spatial resolution of the method are presented. Future applications will also be discussed.