Combining electrodermal responses and cardiovascular measures for probing adaptive automation during simulated flight

Adaptive automation increases the operator's workload in case of hypovigilance and takes over more responsibility if workload becomes too high. Two consecutive studies were conducted to construct a biocybernetic adaptive system for a professional flight simulator, based on autonomic measures. Workload was varied through different stages of turbulences. In a first study with 18 participants, electrodermal responses of experimental subjects oscillated very close to the individual set point, demonstrating that workload level was adjusted as a result of adaptive control, which was not the case in yoked control subjects without adaptive automation. Combining electrodermal responses with heart rate variability in a second study with 48 participants further enhanced the adaptive power which was seen in even smaller set point deviations for the experimental compared to the yoked control group. We conclude that the level of arousal can be adjusted to avoid hypovigilance by combining autonomic measures in a closed loop.     

The effectiveness of producer‐side machine‐independent optimizations for mobile code

Portable mobile code is often executed by a host virtual machine using just‐in‐time compilation. In this context, the compilation time in the host virtual machine is critical. This compilation time can be reduced if optimizations are performed ahead‐of‐time before distribution of the mobile code. Unfortunately, the portable nature of mobile code limits ahead‐of‐time optimizations to those that are machine‐independent. This work examines the effect of machine‐independent optimizations on the performance of mobile code applications. All experiments use the SafeTSA Format, a mobile code format that is based on Static Single Assignment Form (SSA Form). The experiments, which are performed on both the PowerPC and IA32 architectures, indicate that the effects of performing classical machine‐independent optimizations are—in fact—quite machine‐dependent. Nevertheless, the results demonstrate that applying such optimizations in a mobile code system can be beneficial. Copyright © 2009 John Wiley & Sons, Ltd.     

Conductive radical anion salts of poly(butadiene-b-4-vinylpyridine) blockcopolymers

Summary Poly (1,4-butadiene-b-4-vinylpyridine) blockcopolymers are made conductive by formation of the complex salt of the 4-VP-block with tetracyanoquinodimethane (TCNQ). Microphase separated morphologies are obtained where the conductive 4-VP phase is continous or forms a network on a submicron scale in a continous elastomer phase. While the absolute value of the conductivity of 10^-3–10^-4 Scm^-1 depends on the morphology the activation energy typical for an electron hopping process is approximately the same as in the low molecular weight complex with ethylpyridine.     

Chemical Solution Deposition of Columnar-Grained Metallic Lanthanum Nitrate Thin Films

Columnar and (100)-oriented LaNiO₃ thin films were prepared on silicon substrates by a chemical solution deposition (CSD) process using a 0.05 M solution. By reducing the individual layer thickness to 10 nm, columnar LaNiO₃ films with a lateral grain size of ∼120 nm were obtained. The success of this approach required restricting the individual layer thickness to a value below the grain size observed for equiaxed films. This change in microstructure resulted in an improvement in conductivity. The columnar LaNiO₃ film with a thickness of 300 nm showed a resistivity of 4.5 × 10⁻⁵Ω·cm, which is lower by one order of magnitude than that of fine-grain equiaxed films that typically result from CSD methods.     

SCALING IN SITU BIOREMEDIATION PROBLEMS BY APPLICATION OF MULTIPHASE, MULTICOMPONENT TRANSPORT THEORY

A methodology for scaling in situ bioremediation problems is presented. This methodology is based on multiphase, muiticomponent transport theory and employs inspectional analysis and numerical sensitivity studies. A general mathematical model that describes subsurface aerobic biotransformation of organic chemical species in a multiphase setting is first presented. This general model is applied to the specific case of microbial enhanced vapor-vacuum extraction (MEVVE) in a one-dimensional zone of immobile liquids. The resulting simplified MEVVE model considers rate-dependent interphase mass transfer, a flowing gaseous phase, a single hydrocarbon pseudo-component, and either oxygen or hydrocarbon limited microbial activity. By inspectional analysis a set of dimensionless groups are derived that represent the various model parameters. A scries of numerical sensitivity studies are presented that examine the impact of selected dimensionless groups on overall system biotransformation rates. This analysis demonstrates that overall biotranformation rates can be significantly limited not only by insufficient transport of oxygen in the gaseous phase, but also by interfacial mass transfer resistance between nonaqueous phase liquid globules and adjacent fluids. Finally, an examination of the selected dimensionless groups reveals the parameter requirements for properly scaled MEVVE tests. These results indicate the need for further investigation of the importantance of fluid distributions in the pore space and their impact on the design of laboratory and field tests.