Over recent years ionic liquids have gained in importance, causing a growing number of scientists and engineers to investigate possible applications for these liquids because of their unique physical and chemical properties. Their outstanding advantages such as nonflammable liquid within a broad liquid range, high thermal, mechanical, and chemical stabilities, low solubility for gases, attractive tribological properties (lubrication), and very low compressibility, and so forth, make them more interesting for applications in mechanical engineering, offering great potential for new innovative processes, and also as a novel hydraulic fluid. This paper focuses on the outstanding compressibility properties of ionic liquid EMIM-EtSO4, a very important physical chemically property when IL is used as a hydraulic fluid. This very low compressibility (respectively, very high Bulk modulus), compared to the classical hydraulic mineral oils or the non-flammable HFDU type of hydraulic fluids, opens up new possibilities regarding its usage within hydraulic systems with increased dynamics, respectively, systems' dynamic responses.
Improvement in regard to machine energy efficiency is one of the more important goals throughout all fields of research. This is especially true for hydraulically driven machines with large installed power. The use of the appropriate drive concepts, along with a suitable control concept, can result in quite substantial energy savings. Equipping a hydraulic machine with a speed-variable drive and a variable displacement pump enables maximum efficiency tracking for all operating points, represents the most promising drive concept in regard to energy savings. For each operating point, there is an optimal pump setting; consequently, the hydraulic system is able to ensure hydraulic power with minimum losses if the drive components are selected thoughtfully and the system controlled properly. However, in the desire to maximise the system efficiency, the system's responsiveness is too often overlooked.The paper summarises the principle of different drive concepts, along with the drive controller, in terms of the dynamic response and the drive efficiency. Although the speed-variable drive concepts are the most efficient, they have some disadvantages, which are also presented.
The past decade has seen significant advancement in the field of mobile devices. Various smart devices such as cellular phones, tablets and PDAs have become universal tools in our everyday lives. Their versatility is based on their computing power, portability and their integration with other devices and services such as the World Wide Web. However, these smart devices have an even wider usability spectrum. They can also be used for wireless industrial measurements using existing sensors. The wireless connectivity of existing industrial sensors is achieved by equipping them with a Bluetooth module, which digitizes the data and passes it to any Bluetooth capable smart device for further processing, evaluation and logging. This paper describes the specially designed Bluetooth platform for wireless measurements all the way from the basic concept, through hardware, firmware and software implementation, to the sample tests and measurements.
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