Industrial furnaces are analyzed continuously to identify optimization potentials. Process data from the glass industry suggest that the size of a plant has an important influence on the specific ...energy consumption. This leads to incorrect results when using key performance indicators (KPIs) for comparison purposes. Therefore, the evaluation of innovative industrial technologies, as the use of microwaves, is often affected by incomplete assumptions, since economies of scale are often disregarded. A thermodynamic model for energy consumption was developed for analysing the scale dependencies on the specific energy consumption. It contains a correction factor for KPIs. This factor will be compared and validated with industrial process data from literature and databases as well as experimental data for the microwave process. The paper shows the impact of existing scale dependencies and their importance for a comprehensive technology comparison.
Technologies are difficult to assess in an early stage of development. A comparison between innovative and conventional technologies is often complex due to differences in scale (large-scale with ...several 100 t/d vs. demonstrator-scale with less than 100kg/d) and subsequent efficiency. A methodology is implemented using Key Performance Indicators (KPIs) enhanced by Life Cycle Assessment (LCA) aspects and incorporating industrial principles for technology assessment. The methodology is applied to identify the trade-off between direct and indirect emissions and to evaluate scale dependency with focus on energy and broader sustainability. The applicability is illustrated for glass and ceramic frits production and supported by experimental data for conventionally and innovatively heated processes.
Nearly a quarter of the energy consumption of Europe is required for industrial processes. Huge efficiency potentials can be exploited. One such is under research within the EU funded project DAPhNE ...by developing an integrated solution for energy intensive firing processes with microwave technologies. A methodology towards the preliminary definition of Key Performance Indicators (KPIs) with focus on economical, environmental and operational aspects is presented within this paper. By means of lab-scale measurements, the preliminary selected KPIs are determined and benchmarked against conventional KPIs to develop an eco-efficient production system. Moreover life cycle assessment (LCA) results support the evaluation and quantify the environmental benefits of microwave heating. Lab-scale results indicate a high carbon emission reduction potential.
Utilizing the highly correlated quantum NOON states of spins, we have implemented a proof-of-principle quantum thermometer using the NMR technique for measuring the variation of local magnetic field ...with the temperature. The system used was the star topology system of hexafluorophosphate molecules, and the thermometer showed a sensitivity of
85
nT
/
∘
C. Using the hexafluorophosphate and the trimethylphosphite spin systems, we have quantified the advantage of the quantum protocol over the classical one for measuring magnetic field. The quantum protocol showed the best performance for the sensing time of
T
max
=
20
ms, where the errors in the measurement scaled as the Heisenberg limit 1 /
N
. The thermometer implementation provided measurements in the temperature with errors scaling approximately with the Heisenberg limit, more precisely
N
-
0.94
.
Charging racks are used for the positioning and transport of workpieces in heat treatment and high-temperature brazing processes. Conventionally, they are made of steel or cast iron, but in recent ...years, more and more companies have changed over to charging racks made of light-weight materials such as graphite or carbon fiber-reinforced carbon (C/C). However, the main problem of these carbon-based workpiece carriers is the undesired carburization of components, which are in contact with the rack, by means of diffusion processes. For that reason, within the scope of the presented work, thermally sprayed coatings were applied on C/C and extensively tested for their suitability as high-temperature diffusion barrier. The ceramic powders Al2O3, Al2O3/Cr2O3, Al2O3/TiO2 and ZrO2/Y2O3 were chosen as coating materials and processed by powder flame spraying (PFS) and atmospheric plasma spraying (APS). Molybdenum and silicon carbide served as adhesion-promoting intermediate layers. Coating characterization included materialographic analyses, tensile strength and tribometric tests as well as long-term high-temperature tests, both laboratory-scaled and in industrial practice. Especially Al2O3 and Al2O3/Cr2O3 coatings on siliconized C/C exhibited excellent results, proving the wide application potential of thermally sprayed ceramic coatings on carbon-based light-weight materials.
► Ceramic coatings were applied on carbon fiber-reinforced carbon by thermal spraying. ► Extensive laboratory-scaled and industrial-practice thermocyclic tests were conducted. ► APS-sprayed Al2O3 and Al2O3/Cr2O3 on C/C–SiC showed the best thermomechanic behavior. ► The APS coatings exhibited superior wear resistance compared to conventional paints. ► Results offer an energy-saving opportunity to replace steel charging racks.
Utilizing the highly correlated quantum NOON states of particles, we have implemented a proof-of-principle quantum thermometer using the NMR technique for measuring the variation of local magnetic ...field with the temperature variation. The system used was the star-topology system of hexafluorophosphate molecules and the thermometer showed a sensitivity of \(85nT/ ^o C\). Using the hexafluorophosphate and the trimethylphosphite spin systems, we have quantified the advantage of the quantum protocol over the classical one for measuring magnetic field. The quantum protocol showed the best performance for a time evolution in the quantum circuit of \(T = 20ms\), where the errors in the measurement scaled as the Heisenberg limit \(1/N\).
Flexible resource management and scheduling policies require detailed system-state information. Traditional, monolithic operating systems with a centralized kernel derive the required information ...directly, by inspection of internal data structures or maintaining additional accounting data. In systems with distributed or multi-level resource managers that reside in different subsystems and protection domains, direct inspection is unfeasible. In this paper, we present how system event logging - a mechanism usually used in the context of performance analysis and debugging - can also be used for resource scheduling. Event logs provide accumulated, pre-processed, and structured state information independent of the internal structure of individual system components or applications. We describe methods of low-overhead data collection and data analysis and present a prototypical application to multiprocessor scheduling of virtual machines
Aerodynamic performance of small-scale fixed-wing flight is not well understood, and flight data are needed to gain a better understanding of the aerodynamics of micro air vehicles (MAVs) flying at ...Reynolds numbers between 10,000 and 30,000. Experimental studies have shown the aerodynamic effects of low Reynolds number flow on wings and airfoils, but the amount of work that has been conducted is not extensive and mostly limited to tests in wind and water tunnels. In addition to wind and water tunnel testing, flight characteristics of aircraft can be gathered through flight testing. The small size and low weight of MAVs prevent the use of conventional on-board instrumentation systems, but motion tracking systems that use off-board triangulation can capture flight trajectories (position and attitude) of MAVs with minimal onboard instrumentation. Because captured motion trajectories include minute noise that depends on the aircraft size, the trajectory results were verified in this work using repeatability tests. From the captured glide trajectories, the aerodynamic characteristics of five unpowered aircraft were determined. Test results for the five MAVs showed the forces and moments acting on the aircraft throughout the test flights. In addition, the airspeed, angle of attack, and sideslip angle were also determined from the trajectories. Results for low angles of attack (less than approximately 20 deg) showed the lift, drag, and moment coefficients during nominal gliding flight. For the lift curve, the results showed a linear curve until stall that was generally less than finite wing predictions. The drag curve was well described by a polar. The moment coefficients during the gliding flights were used to determine longitudinal and lateral stability derivatives. The neutral point, weather-vane stability and the dihedral effect showed some variation with different trim speeds (different angles of attack). In the gliding flights, the aerodynamic characteristics exhibited quasi-steady effects caused by small variations in the angle of attack. The quasi-steady effects, or small unsteady effects, caused variations in the aerodynamic characteristics (particularly incrementing the lift curve), and the magnitude of the influence depended on the angle-of-attack rate. In addition to nominal gliding flight, MAVs in general are capable of flying over a wide flight envelope including agile maneuvers such as perching, hovering, deep stall and maneuvering in confined spaces. From the captured motion trajectories, the aerodynamic characteristics during the numerous unsteady flights were gathered without the complexity required for unsteady wind tunnel tests. Experimental results for the MAVs show large flight envelopes that included high angles of attack (on the order of 90 deg) and high angular rates, and the aerodynamic coefficients had dynamic stall hysteresis loops and large values. From the large number of unsteady high angle-of-attack flights, an aerodynamic modeling method was developed and refined for unsteady MAV flight at high angles of attack. The method was based on a separation parameter that depended on the time history of the angle of attack and angle-of-attack rate. The separation parameter accounted for the time lag inherit in the longitudinal characteristics during dynamic maneuvers. The method was applied to three MAVs and showed general agreement with unsteady experimental results and with nominal gliding flight results. The flight tests with the MAVs indicate that modern motion tracking systems are capable of capturing the flight trajectories, and the captured trajectories can be used to determine the aerodynamic characteristics. From the captured trajectories, low Reynolds number MAV flight is explored in both nominal gliding flight and unsteady high angle-of-attack flight. Building on the experimental results, a modeling method for the longitudinal characteristics is developed that is applicable to the full flight envelope.
Despite its current popularity, para-virtualization has an enormous cost. Its deviation from the platform architecture abandons many of the benefits of traditional virtualization: stable and ...well-defined platform interfaces, hypervisor neutrality, operating system neutrality, and upgrade neutrality - in sum, modularity. Additionally, para-virtualization has a significant engineering cost. These limitations are accepted as inevitable for significantly better performance, and for the ability to provide virtualization-like behavior on non-virtualizable hardware such as times86. Virtualization and its modularity solve many systems problems, and when combined with the performance of para-virtualization become even more compelling. We show how to achieve both together. We still modify the guest operating system, but according to a set of design principles that avoids lock-in, which we call soft layering. Additionally, our approach is highly automated and thus reduces the implementation and maintenance burden of paravirtualization, which is especially useful for enabling obsoleted operating systems. We demonstrate soft layering on times86 and itanium: we can load a single Linux binary on a variety of hypervisors (and thus substitute virtual machine environments and their enhancements), while achieving essentially the same performance as para-virtualization with less effort.
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