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Engine adaptation for alternative fueling may generate certain difficulties in terms of configuration or quality of the subassemblies. The main actuator of a modern LPG (Liquefied Petroleum Gas) system is the vapor phase injector. These systems are commonplace because of the possibility of a modification of the mixture composition in order to meet the emission standards. Multitude of injector design solutions and quality of their workmanship frequently make them the main reason for system malfunction, hence, the need to apply simplified research methods in the course of operation that would allow an assessment of their technical condition. The paper directly compares selected research procedures evaluating their applicability. The proposed method of pressure measurement at the outlet of the injector nozzle turned out to be sufficient for a non-invasive assessment of the technical condition of the injector, which was confirmed by the measurement of the injector piston lift by the displacement sensor. The current on the power line and the vibrations of the injector housing have been sufficient to diagnose the subassembly, thus supporting the decision on the extent of the repair. [ABSTRACT FROM AUTHOR]

This paper concerns laminates made of composite plies with piezoelectric actuators. The subject of the paper is the research of laminates having, in some directions, null expansion coefficients in extension or having the same expansion coefficient in each direction (isotropic behavior). The general equations for the problem are given in the theoretical framework of the so-called polar method for the representation of plane tensors. Some simple formulas are given for the case of expansion coefficients of a standard plate introduced in the paper. Some numerical examples close the paper. [ABSTRACT FROM AUTHOR]

The article analyzes the performance of a negative-stiffness vibroisolating table in the range of a frequency of 2--110 Hz and reviews other possible ways of vibroisolating. The paper deals with conducted experimental tests on the transmissibility of vibrations employing specific tested equipment for vibration excitation enabling to execute research facilities. The article also describes the methodology of experimental tests and presents the obtained results and conclusions of experimental analysis. [ABSTRACT FROM AUTHOR]

Usually when piezoelectric membrane actuators are mentioned, one classically thinks of a passive membrane with a piezoelectric actuator on top. In this paper omitting the passive membrane will be suggested. Therefore, the piezoelectric actuator will not be commonly designed as plate capacitor structure, such as that the piezoelectric material sitting between two plate electrodes. Rather will the actuation be caused by structured surface electrodes on only one side of the piezoelectric material, leaving the opposite side free of potential. Several surface electrode designs, starting with interdigital parallel structures, known from surface acoustic wave transducers, spiral and ring structures, ending with star-shaped structures, are tested. The main advantage of this actuation principle is that with the varying electrode design it became possible to also generate an upward movement, i.e., in the direction of electrode side of the membrane. This upward movement has not been achieved with any piezoelectric membrane actuator so far. [ABSTRACT FROM AUTHOR]

In the nearly six decades since researchers began to explore methods of creating them, exoskeletons have progressed from the stuff of science fiction to nearly commercialized products. While there are still many challenges associated with exoskeleton development that have yet to be perfected, the advances in the field have been enormous. In this paper, were review the history and discuss the state-of-the-art of lower limb exoskeletons and active orthoses. We provide a design overview of hardware, actuation, sensory, and control systems for most of the devices that have been described in the literature, and end with a discussion of the major advances that have been made and hurdles yet to be overcome. [ABSTRACT FROM AUTHOR]