Real-Time Volume Deformations

Real-time free-form deformation tools are primarily based on surface or particle representations to allow for interactive modification and fast rendering of complex models. The efficient handling of volumetric representations, however, is still a challenge and has not yet been addressed sufficiently. Volumetric models, on the other hand, form an important class of representation in many applications. In this paper we present a novel approach to the real-time deformation of scalar volume data sets taking advantage of hardware supported 3D texture mapping. In a prototype implementation a modeling environment has been designed that allows for interactive manipulation of arbitrary parts of volumetric objects. In this way, any desired shape can be modeled and used subsequently in various applications. The underlying algorithms have wide applicability and can be exploited effectively for volume morphing and medical data processing.     

Automated bidding in computational markets: an application in market-based allocation of computing services

Autonomous agents are widely applied to automate interactions in robotics, e.g. for selling and purchasing goods on eBay, and in financial markets, e.g. in the form of quote machines and algorithmic traders. Current research investigates efficient economic mechanisms that fully automate the provisioning and usage processes of Grid-based services. On the one hand, consumers want to allocate resources on demand for their various applications, e.g. data sharing, stream processing, email, business applications and simulations. On the other hand, providers of Grid services want to govern business policies to meet their utilization and profit goals. The above-mentioned processes are not manually manageable, however, because decisions need to be taken within milliseconds. Therefore, such processes have to be automated to minimize human interactions. Hence, market mechanisms and strategic behavior play important roles when it comes to achieving automated and efficient allocation of Grid services. The paper begins by presenting a framework for automated bidding, providing a methodology for the design and implementation of configurable bidding strategies. Second, it presents a novel bidding strategy based on a reinforcement learning technique. This strategy is designed to automate the bid generation processes of consumers and providers in various market mechanisms. Third, the behavior and convergence of the strategy is evaluated in a centralized Continuous Double Auction and a decentralized on-line machine scheduling mechanism against selected benchmark bidding strategies. Fourth, we define a bidding language for communicating consumer and provider preferences to the market as well as report back the match of the market-based allocation process.     

Model based prediction of required cut size diameter for fractionation of fly ash from a grate-fired wood chip incineration plant

Utilization of biomass ash as a soil improvement material is limited by the admissible input of heavy metals. It is well known that heavy metal concentrations are increased in fine ash fractions. In this study, two models are investigated to describe the distribution of various heavy metals in different size fractions of fly ash from a grate-fired biomass incineration plant incinerating wood chips. The second model assuming a dependence of the heavy metal concentration from the reciprocal particle diameter to the power of the variable N correlated well with measured concentrations. This model was then used in the calculation of the required cut size of a classifier for the production of a coarse fraction with heavy metal concentrations below limits from a fly ash sample exceeding the Austrian limits for a soil improvement material. The predicted concentrations of the critical heavy metals Cd and Pb and the total mass of the coarse fraction produced corresponded well with measured values, and although the concentration of Zn was considerably underestimated in the model, the produced coarse fraction was within the limits for utilization.     

Potential of Integrated Semi-Continuous Enzymatic Synthesis and Filtration Processes for Efficiency Enhancement

Galacto-oligosaccharides (GOS), increasingly popular prebiotics, are synthesized by enzymatic conversion of lactose. Among others, the total production costs are significantly influenced by the costly enzyme. Therefore, it was investigated if the reuse and full recovery of the enzyme is feasible, followed by the development of a semi-continuous process in order to maintain a consistent high GOS yield. As a preliminary step, the enzyme-catalyzed reaction was recorded within the permissible operating parameters. It was successfully shown that steady high GOS yields can be synthesized semi-continuously within a filtration plant functioning as an enzymatic membrane reactor.     

Regulating Li-Ion Transport through Ultrathin Molecular Membrane to Enable High-Performance All-Solid-State–Battery

Solid-state lithium metal batteries with garnet-type electrolyte provide several advantages over conventional lithium-ion batteries, especially for safety and energy density. However, a few grand challenges such as the propagation of Li dendrites, poor interfacial contact between the solid electrolyte and the electrodes, and formation of lithium carbonate during ambient exposure over the solid-state electrolyte prevent the viability of such batteries. Herein, an ultrathin sub-nanometer porous carbon nanomembrane (CNM) is employed on the surface of solid-state electrolyte (SSE) that increases the adhesion of SSE with electrodes, prevents lithium carbonate formation over the surface, regulates the flow of Li-ions, and blocks any electronic leakage. The sub-nanometer scale pores in CNM allow rapid permeation of Li-ions across the electrode–electrolyte interface without the presence of any liquid medium. Additionally, CNM suppresses the propagation of Li dendrites by over sevenfold up to a current density of 0.7 mA cm⁻² and enables the cycling of all-solid-state batteries at low stack pressure of 2 MPa using LiFePO₄ cathode and Li metal anode. The CNM provides chemical stability to the solid electrolyte for over 4 weeks of ambient exposure with less than a 4% increase in surface impurities.     

Long‐range wireless sensor networks with transmit‐only nodes and software‐defined receivers

Wireless sensor networks for environmental monitoring and agricultural applications often face Long‐range requirements at low bit rates together with a large numbers of nodes. This paper presents the design and test of a novel wireless sensor network that combines a large radio range with very low power consumption and cost. Our asymmetric sensor network uses ultra‐low‐cost 40‐MHz transmitters and a sensitive software‐defined radio receiver with multi‐channel capability. Experimental radio range measurements in two different outdoor environments demonstrate a single‐hop range of up to 1.8 km. A theoretical model for radio propagation at 40 MHz in outdoor environments is proposed and validated with the experimental measurements. The reliability and fidelity of network communication over longer periods is evaluated with a deployment for distributed temperature measurements. Our results demonstrate the feasibility of the transmit‐only low‐frequency system design approach for future environmental sensor networks. Although there have been several papers proposing the theoretical benefits of this approach, to the best of our knowledge, this is the first paper to provide experimental validation of such claims. Copyright © 2011 John Wiley & Sons, Ltd.     

Accelerator mass spectrometry of U at low energies

The performance of the compact ETH-TANDY system for accelerator mass spectrometry measurements of ²³⁶U is presented. Despite the low ion energies of around 1.2 MeV we can demonstrate a background level that is comparable to larger facilities. The careful ion-optical design of the high-energy spectrometer leads to a high suppression of neighboring isotopes sufficient to measure samples with isotopic ratios of ²³⁶U/²³⁸U > 10^-11 the ion chamber only, as demonstrated by systematic investigations with different slit settings and time-of-flight measurements. Additionally, a high overall efficiency is achieved due to a high transmission through the accelerator.