Transforming car glass into microphones using piezoelectric transducers

The use of car windows as a long range acoustic sensing device for external alarm signals is described in this paper. The goal is to detect and localize siren signals (e.g. ambulances and police cars) and to alert presbycusic drivers of its presence by visual and acoustic feedback in order to improve individual mobility and increase the sense of security. The glass panes of a Renault Zoé operating as an acoustic antenna have been equipped with large 50 mm outer diameter piezoceramic rings, hidden in the lower part of the door structure and the lower part of the windshield and the rear window. The response of the glass to a sweep excitation has been recorded. In general, the glass pane is acting as a high pass filter due to its inherent stiffness and provides only little damping. This effect is compensated by using a charge amplifier electronic circuit. The detection capability up to 120 m in static conditions as well as the influence of wind and vibration during driving conditions is shown. Finally, two alarm detection scenarios are reported with the car passing by a static alarm source once facing the car and once orthogonally to the driving direction.     

ICD/ITKE Research Pavilion 2014–15: Fibre Placement on a Pneumatic Body Based on a Water Spider Web

Process-based biomimetics focuses on the transfer of biological principles to architectural construction. To realise the ICD/ITKE Research Pavilion 2014 -15, presented here by Moritz Doerstelmann, Jan Knippers, Valentin Koslowski, Achim Menges, Marshall Prado, Gundula Schieber and Lauren Vasey of the Institute for Computational Design (ICD) and Institute of Building Structures and Structural Design (ITKE) research team at the University of Stuttgart, sensor-driven robotic fabrication was combined with advanced design computation and simulation. This enabled the construction of an architectural fibre structure on a pneumatic mould, drawing on the complex design of the web of a water spider.     

Characterization of Oxide Scales Formed on Ferritic Stainless Steel 441 at 1,100 °C under water vapor

This study focuses on the characterization of the oxide scales formed after different exposure times in the range of 2.5–20 min. A commercially available ferritic steel grade AISI 441 was exposed to wet argon at 1100 °C with 5, 9 and 13% H₂O. Raman microspectroscopy, XRD, EDS and XPS were used to fully characterize the oxide scale. For all samples exposed for over 4 min, the scale was constituted of three layers in this order: a thin top layer of spinel phases (Fe,Cr,Mn)₃O₄ with local outgrowths; a second and main layer of Cr₂O₃ + (Mn,Cr)₃O₄; and finally a bottom layer of SiO₂. The uncommon presence of Fe in the top layer was also observed.     

Determination of Drop-Test Behavior of a Sample Peach Using Finite Element Method

It is very important to determine mechanical damage quantity of fruit and vegetables during harvesting, handling, transportation, and storage. Specifically, determining damage quantity of agricultural products is very difficult on existing external forces. However, one of the useful methods is the finite elements method that can be used in different engineering disciplines to simulate the behavior of materials under the defined boundary conditions. In this study, a drop-test simulation was performed for peach samples by means of finite elements method. Some mechanical properties of the sample were measured by an experimental study (compressive test) and the obtained data were used in the finite elements method simulation. The stress-strain and force-deformation curve of peaches were determined as maximum force, Poisson’s ratio, specific deformation, modulus of elasticity, stress, and deformation energy were found to be: 59.6 N, 0.29, 10.9%, 0.89 Nmm^–2, 1.19 Nmm^–2, and 162.2 Nmm, respectively. At the end, the distribution of stress and shape of deformation of sample peaches at impact was obtained. When the stress magnitudes were evaluated, simulation outputs showed that simulation stress values are quite a bit compatible with experimental data.     

Antibiotic‐Releasing Silk Biomaterials for Infection Prevention and Treatment

Effective treatment of infections in avascular and necrotic tissues can be challenging due to limited penetration into the target tissue and systemic toxicities. Controlled‐release polymer implants have the potential to achieve the high local concentrations needed while also minimizing systemic exposure. Silk biomaterials possess unique characteristics for antibiotic delivery, including biocompatibility, tunable biodegradation, stabilizing effects, water‐based processing, and diverse material formats. The functional release of antibiotics spanning a range of chemical properties from different material formats of silk (films, microspheres, hydrogels, coatings) is reported. The release of penicillin and ampicillin from bulk‐loaded silk films, drug‐loaded silk microspheres suspended in silk hydrogels and bulk‐loaded silk hydrogels is investigated and the in vivo efficacy of the ampicillin‐releasing silk hydrogels is demonstrated in a murine infected‐wound model. Silk sponges with nanofilm coatings are loaded with gentamicin and cefazolin, and release is sustained for 5 and 3 days, respectively. The capability of silk antibiotic carriers to sequester, stabilize, and then release bioactive antibiotics represents a major advantage over implants and pumps based on liquid drug reservoirs, where instability at room or body temperature is limiting. The present studies demonstrate that silk biomaterials represent a novel, customizable antibiotic platform for focal delivery of antibiotics using a range of material formats (injectable to implantable).     

Oral-based controlled release formulations using poly(acrylic acid) microgels

Aim: To investigate the release of hydrophobic and hydrophilic substances from tablets containing Pemulen and Carbopol as excipients. Method: The dissolution patterns of a hydrophobic (diazepam) and a hydrophilic active substance (midodrine-HCl) from different tablet formulations containing a nonmodified polyacrylic microgel (Carbopol 981 F) or a hydrophobically modified polyacrylic microgel (Pemulen®) have been studied. Possible differences in dissolution in phosphate buffer (pH 6.8) and in 0.1 M HCl between tablets produced using wet granulation and direct compression were also investigated. Results: Tablets produced by wet granulation had a greater effect on the release of active substance from the tablets. No major differences were observed in the release patterns of the hydrophilic substance midodrine-HCl from wet granulated tablets based on Carbopol and Pemulen. However, the release pattern of the more hydrophobic drug substance, diazepam, differed considerably between the two polymers. Wet granulation gave reproducible release patterns. The release patterns from the polymers differed considerably at pH 6.8 but were similar at low pH. Conclusions: The release of the diazepam from the hydrophobic polymer Pemulen was very slow, and the release was close to zero order.     

Stabilization of periodic orbits near a subcritical Hopf bifurcation in delay-coupled networks

We study networks of delay-coupled oscillators with the aim to extend time-delayed feedback control to networks. We show that unstable periodic orbits of a network can be stabilized by a noninvasive, delayed coupling. We state criteria for stabilizing the orbits by delay-coupling in networks and apply these to the case where the local dynamics is close to a subcritical Hopf bifurcation, which is representative of systems with torsion-free unstable periodic orbits. Using the multiple scale method and the master stability function approach, the network system is reduced to the normal form, and the characteristic equations for Floquet exponents are derived in an analytical form, which reveals the coupling parameters for successful stabilization. Finally, we illustrate the results by numerical simulations of the Lorenz system close to a subcritical Hopf bifurcation. The unstable periodic orbits in this system have no torsion, and hence cannot be stabilized by the conventional time delayed-feedback technique.     

Interval timing as an emergent learning property.

Interval timing in operant conditioning is the learned covariation of a temporal dependent measure such as wait time with a temporal independent variable such as fixed-interval duration. The dominant theories of interval timing all incorporate an explicit internal clock, or "pacemaker," despite its lack of independent evidence. The authors propose an alternative, pacemaker-free view that demonstrates that temporal discrimination can be explained by using only 2 assumptions: (a) variation and selection of responses through competition between reinforced behavior and all other, elicited, behaviors and (b) modulation of the strength of response competition by the memory for recent reinforcement. The model departs radically from existing timing models: It shows that temporal learning can emerge from a simple dynamic process that lacks a periodic time reference such as a pacemaker. (PsycINFO Database Record (c) 2010 APA, all rights reserved)