Thermometry plays an extremely important role in engineering and basic sciences. Accurate measurements of temperature are vital for: (a) improving our understanding of various physical phenomena; (b) process control and optimization; (c) determination of material properties; and (d) energy conservation. This review highlights some of the developments that have occurred in thermometry during the period 1984 to 2011. The ensuing discussions focus on the physical principles that have been exploited for the purpose of thermometry. The developments mentioned in this review offer a peek into the past 27 years of thermometry research that has produced several innovations based upon optical refraction, luminescence, fluorescence, thermo-reflectance, color change, radiation, ferro-electricity, acoustic resonance, Raman Effect, and magnetic resonance principles, to name a few. In tune with the emergent interest in micro/nano-scale interdisciplinary technologies, automated high-speed manufacturing processes, and advances in medical engineering, many of the patents reviewed here relate to thermometry for specialized applications. A sizeable majority of these novel arrangements are non-intrusive and non-contact in nature, suitable for remote measurements. Developments on contact-type temperature sensors, that may require invasive techniques and arrangements, are also presented.
The present paper reviews recent patents disclosing various ways to monitor the variation of the bolt tension in order to timely readjust the torque to initial specifications. The recent advances related to bolted joints have seen tremendous developments to ease inspection of the fastening tension in both visual and remote inspections. Precision of bolt tightening is one of the major issues noted in industrial plants where accurate preload is questioned whether it is achieved or not. Insufficient preload, caused by an inaccurate tightening method, is a frequent cause of bolted joint failure which may lead to potentially catastrophic structural failures. The loss of tension may occur due to vibration, thermal effects, change in the material characteristics and so on. Reviews of recent related developments are discussed in this paper with proposal of intended features for smart bolts.
A very high accuracy and resolution, stability, and fast response are the requirements of high precision positioning systems (HPPS). Accurate position sensing and feedback control of the motion are key to the successful precision positioning. In this paper, the robust control of HPPS literature published within last two decades is categorized and discussed. The paper also provides detailed technical descriptions on many such novel methods. According to the type of the control methodology applied in the reviewed literature, the paper categorizes them into seven main categories. The purpose is to emphasize the key role of advanced control techniques in improving precision, accuracy, and the speed of operation of these systems. While doing so, the paper also reviews literature on various applications of robust control for HPPS including some recent patents. However, the list of patents reviewed is not the least assumed to be complete or general. Nevertheless, the evolution and trends in the applications of robust control methods are shown. Based on the analysis of the reviewed patents, the expected future developments in this domain are highlighted.
High speed machining (HSM) is a promising technology for drastically increasing productivity and reducing production costs. Development of high speed spindle technology is strategically critical for researchers to implement HSM. High speed spindles are notorious for their sudden catastrophic failures without alarming signs at high speed due to thermal problems. This paper reviews various patents on thermal characteristics and water-cooling system of high speed motorized spindle and, based on the calculation theory of heat conduction, the finite element software was applied in the simulation and analysis of high speed spindle system aimed at dealing with difficulties in calculating the amount of cooling water and measuring the temperature distribution of helical water-cooling system of the high speed spindle. A finite element thermal model is developed to characterize the heat distribution of a high speed motorized spindle, in particular the characterization of helical water-cooling system. The simulation result, experimental validation and sensitivity analysis show that temperature increase could be significantly reduced with the application of helical water cooling system. Based on the simulation analysis, we can predict the temperature distribution and development of helical water-cooling system when the motorized spindle endures various ambient temperatures and reduces the trial modification times of the water-cooling system design to achieve high efficiency and lower manufacturing cost.