A piezoelectric energy harvester with a mechanical end stop on one side

Nonlinear effects as severe as proof mass impact on mechanical end stops are potentially useful for energy harvesting. In this paper, we present measurements and modeling of a piezoelectric energy harvester with a mechanical end stop on one side. At high acceleration levels we observe nonlinear effects related to impacts on the end stop such as an enlarged up-sweep bandwidth in frequency sweeps. Based on SPICE simulations of an electrical equivalent circuit for the device, we show that modeling of the end stop as a parallel spring-dashpot system is sufficient to recapture the energy harvester behavior.     

Direct simulation Monte Carlo for simultaneous nucleation, coagulation, and surface growth in dispersed systems

A Monte Carlo simulation technique is developed to describe dispersed phase systems. The method is formulated for simultaneous coagulation, nucleation and surface growth, but can be extended to include other processes. These processes are considered in an initially constant simulation volume. The changes in the particle ensemble are determined by a random choice procedure, while the particle number in the simulation volume changes according to the chosen events. Every time, when the particle number in the simulation volume increases or decreases by a factor of two of its initial value, the simulation volume is halved or doubled, respectively. Therefore, this method is called a stepwise constant-volume Monte Carlo simulation. It allows to use only several thousands simulation particles, even if the particle number concentration experiences changes of several orders of magnitude. The simulations are validated through a comparison with the exact mathematical solutions for several simple cases. An example of simultaneous nucleation and coagulation in the free-molecular region demonstrates, that the stepwise constant-volume Monte Carlo simulations lead to more accurate results than the constant-number Monte Carlo simulations.     

Comparison of geophysical methods for sub-surface mapping of faults and fracture zones in a section of the Viggja road tunnel, Norway

Results from site investigations, 2D resistivity, refraction seismic and VLF on a section of tunnel near Trondheim, show that 2D resistivity data are most valuable for interpreting geological structures in the sub-surface. VLF only identifies zones and does not indicate thickness, width or dip direction. The method is also sensitive to technical installations. Refraction seismic is valuable for mapping depth to bedrock, location and width of fracture zones but cannot indicate the depth or dip direction of such zones. With 2D resistivity, the position of a zone is well identified. This method may also provide information on the depth and width of the zone as well as the dip direction. In most cases 2D resistivity clearly identifies zones in the bedrock that can be observed as fault and/or fracture zones in the tunnel. The results described in this paper show a good correlation between the resistivity profiles, mapped structures on the surface and mapped zones in the tunnel.     

Verifying traits: an incremental proof system for fine-grained reuse

Traits have been proposed as a more flexible mechanism than class inheritance for structuring code in object-oriented programming, to achieve fine-grained code reuse. A trait originally developed for one purpose can be adapted and reused in a completely different context. Formalizations of traits have been extensively studied, and implementations of traits have started to appear in programming languages. So far, work on formally establishing properties of trait-based programs has mostly concentrated on type systems. This paper presents the first deductive proof system for a trait-based object-oriented language. If a specification of a trait can be given a priori, covering all actual usage of that trait, our proof system is modular as each trait is analyzed only once. However, imposing such a restriction may in many cases unnecessarily limit traits as a mechanism for flexible code reuse. In order to reflect the flexible reuse potential of traits, our proof system additionally allows new specifications to be added to a trait in an incremental way which does not violate established proofs. We formalize and show the soundness of the proof system.     

User-defined schedulers for real-time concurrent objects

Scheduling concerns the allocation of processors to processes, and is traditionally associated with low-level tasks in operating systems and embedded devices. However, modern software applications with soft real-time requirements need to control application-level performance. High-level scheduling control at the application level may complement general purpose OS level scheduling to fine-tune performance of a specific application, by allowing the application to adapt to changes in client traffic on the one hand and to low-level scheduling on the other hand. This paper presents an approach to express and analyze application-specific scheduling decisions during the software design stage. For this purpose, we integrate support for application-level scheduling control in a high-level object-oriented modeling language, Real-Time ABS, in which executable specifications of method calls are given deadlines and real-time computational constraints. In Real-Time ABS, flexible application-specific schedulers may be specified by the user, i.e., developer, at the abstraction level of the high-level modeling language itself and associated with concurrent objects at creation time. Tool support for Real-Time ABS is based on an abstract interpreter that supports simulations and measurements of systems at the design stage.     

烧成温度对低热水泥性能的影响及其机理研究

检测了不同烧成温度制成的低热水泥的物理性能及水化速率，并采用岩相分析、XRD、EDS﹑化学分析方法研究了不同烧成温度对低热水泥熟料岩相结构﹑矿物组成、矿物晶型及矿物固溶组分的影响。结果表明，低温烧制的熟料中C4A3S的生成及C3A、C4AF含量相对较多是低温烧制的低热水泥早期强度较高的主要原因;而高温烧成的熟料中高温晶型C2S含量高，B矿中固溶SO3、Al2O3、Fe2O3多，B矿的Ca/Si增高，水化活性增大，这是高温烧成的低热水泥后期强度较高的主要原因。     

A quantum multiply-accumulator

This paper proposes a quantum multiply-accumulator circuit (QMAC), which can perform the calculation on conventional integers faster than its classical counterpart. Whereas classically applying a multiply–adder (MAC) $n$ times to $k$ bit integers would require $O(n \log k)$ parallel steps, the hybrid QMAC needs only $O(n + k)$ steps for the exact result and $O(n + \log k)$ steps for an approximate result. The proposed circuit could potentially be embedded in a conventional computer architecture as a quantum device or accelerator, enabling a wide range of applications to execute faster.     

Paint robotics—improving automotive painting performance

Robotic painting has achieved increased popularity in recent years, due to the flexibility and enhanced performance with such systems.There is a clear trend among major automobile makers to change from hard to flexible automation, and, in that respect, paint robotics is becoming increasingly more important for future paint shop design.New programming tools offer operators and paint engineers better possibility to program and maintain robot systems.With the introduction of the laser, a powerful tool is now available for real-time, in-line control of film build and the related paint process.With the additional advances in robotic-based quality inspection systems, such as a robot-mounted quality inspection camera systems, automotive manufacturers now have the possibility to document and store literally all paint quality data for a multitude of purposes related to process control.Combining these technologies offers a glimpse of a future where true closed-loop process control and quality monitoring can be used to diminish significantly the variation in paint application systems, improve flexibility, quality, and reduce operational costs, while at the same time reduce the complexity of robotic painting systems.     

Multiparameter Characterization of Aerosols

The performance of particle‐based products depends on a multiple set of particle properties. To monitor them during particle manufacturing, three novel aerosol measurement techniques were developed: wide‐angle light scattering (WALS), three‐dimensional laser scattering (3D‐LSS), and differential aerodynamic particle sizing (DAPS). They measure particle shape, aggregate structure, and particle size, i.e., radius of gyration and aerodynamic diameter. The techniques were tested for rod‐like organic pigments and partially sintered SiO₂ aggregates, which were produced by two new aerosol generators.