A problem facing the casting industry is inclusions in the finished parts. The inclusions can be sand from the molds, oxides or other impurities in the metal charge. Inclusions lead to costly part repairing or reworking. A study was done to try and find inclusion trapping devices that could be placed in the gating system. The experiments consisted of pouring water and suitable inclusion models into clear, full scale, plastic molds. The fills were video taped for later analysis. The efficiency of the trapping device was determined from the end location of the inclusions. No work was done on other anti-inclusion methods such as ceramic filters, bottom pour ladles, chemical additives, etc. The research showed that a swirl chamber which used centrifugal force to separate inclusions worked quite well if set up correctly. The optimum setup was a vertical swirl chamber with a well. The inlet passage was choked and located below the exit passage. It also worked much better than any setup which tried to use buoyancy for separation. The large volume of the swirl chamber may be objectionable. However, properly shaped inserts, such as an ice-cream cone shape, can be put into the chamber to reduce fill volume while still maintaining good efficiency and fills. The efficiencies of the chambers behave as expected; faster pours are less efficient and bigger chambers (for a constant size mold) are more efficient. The use of outlet chokes may or may not improve separation efficiency, but will improve the filling of the part cavity. / Graduation date: 1993

Thesis (M. Eng. Sc.)--University of Queensland, 2002. / Includes bibliographical references.

No description available.

This thesis describes the open-loop behavior of an ionic polymer metal composite (IPMC) strip as a novel actuator, the empirical force and position models, the control system and the improved dynamic characteristics with the feedback control implemented. Ionic polymer metal composite is a novel polymer in the class of electroactive polymers. IPMC consists of a base polymer coated with electrodes made up of highly conducting pure metals such as gold. The actuation behavior of IPMC can be attributed to the bending of an IPMC strip upon application of voltage across its thickness. The main reasons for the bending are ion migration on the application of voltage and swelling and contraction caused by water content. An experimental setup to study the open-loop force and tip displacement of an IPMC strip in a cantilever configuration was developed, and real time controllers were implemented. In open loop, the force response of the IPMC strip of dimensions 25 mm x 3.9 mm x 0.16 mm to a 1.2-V step input is studied. The open-loop rise time was 0.08 s and the percent overshoot was 131.62 %, while the settling time was about 10 s. Based on this open-loop step response using a least-square curve-fitting methodology, a fourth-order empirical transfer function from the voltage input to the force output was derived. The tip displacement response of an IPMC strip of dimensions 23 mm x 3.96 mm x 0.16 mm to a 1.2-V step input was also studied. The step response exhibited a 205.34 % overshoot with a rise time of 0.08 s, and the settling time was 27 s. A fourth-order empirical transfer function from the step input to the tip displacement as output was also derived. Based on the derived transfer functions lead-lag feedback controllers were designed for precision control of both force and displacement. The control objectives were to decrease the settling time and the percent overshoot, and achieve reference input tracking. After implementing the controllers, the percent overshoot decreased to 30% while the settling time was reduced to 1.5 s in case of force control. With position control, the settling time was reduced to 1 s while the percent overshoot decreased to 20%. Precision micro-scale force and position-control capabilities of the IPMC were also demonstrated. A 4 ?N force resolution was achieved, with a force noise of 0.904-?N rms. The position resolution was 20 ?m with a position noise of 7.6-?m rms.

This thesis describes the open-loop behavior of an ionic polymer metal composite (IPMC) strip as a novel actuator, the empirical force and position models, the control system and the improved dynamic characteristics with the feedback control implemented. Ionic polymer metal composite is a novel polymer in the class of electroactive polymers. IPMC consists of a base polymer coated with electrodes made up of highly conducting pure metals such as gold. The actuation behavior of IPMC can be attributed to the bending of an IPMC strip upon application of voltage across its thickness. The main reasons for the bending are ion migration on the application of voltage and swelling and contraction caused by water content. An experimental setup to study the open-loop force and tip displacement of an IPMC strip in a cantilever configuration was developed, and real time controllers were implemented. In open loop, the force response of the IPMC strip of dimensions 25 mm x 3.9 mm x 0.16 mm to a 1.2-V step input is studied. The open-loop rise time was 0.08 s and the percent overshoot was 131.62 %, while the settling time was about 10 s. Based on this open-loop step response using a least-square curve-fitting methodology, a fourth-order empirical transfer function from the voltage input to the force output was derived. The tip displacement response of an IPMC strip of dimensions 23 mm x 3.96 mm x 0.16 mm to a 1.2-V step input was also studied. The step response exhibited a 205.34 % overshoot with a rise time of 0.08 s, and the settling time was 27 s. A fourth-order empirical transfer function from the step input to the tip displacement as output was also derived. Based on the derived transfer functions lead-lag feedback controllers were designed for precision control of both force and displacement. The control objectives were to decrease the settling time and the percent overshoot, and achieve reference input tracking. After implementing the controllers, the percent overshoot decreased to 30% while the settling time was reduced to 1.5 s in case of force control. With position control, the settling time was reduced to 1 s while the percent overshoot decreased to 20%. Precision micro-scale force and position-control capabilities of the IPMC were also demonstrated. A 4 ?N force resolution was achieved, with a force noise of 0.904-?N rms. The position resolution was 20 ?m with a position noise of 7.6-?m rms.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / This paper discusses the importance of time measurement and the necessity of time measurement accuracy to data acquisition and analysis. It briefly reviews how time is used in data analysis and how to determine what amount of jitter, latency and phase error is acceptable for various data acquisition systems and analysis methodology. It discusses the relevance of various measurement timing errors and how some of them may be corrected. Finally, this paper discusses various approaches to time tagging of measurements in a distributed network based data system where data is packetized for efficient transmission.

5 pp. / In this publication we make a recount of basic terms and acronyms used in describing the functionality and capabilities of precision agriculture technologies. Growers seeking to acquire new systems or upgrade their existing equipment need to be fluent in terminology used in communications, hardware, software, and other areas in order to make good decisions at the time of buying equipment. This information is also useful to educate equipment operators in the in-and-outs of this technology and this way be able to maximize the use of these expensive upgrades.

7 pp. / In this publication, we will make the case of what Precision Agriculture (PA) technologies can do to enhance the productivity of farming systems, with particular attention to the case of irrigated agriculture in the semi-arid Arizona. This guide is intended to aid growers to select the right technology when considering the need to acquire new, or upgrade existing equipment.

No description available.

The machining of brittle materials such as glasses and ceramics is an area of rising interest in the 'Precision Engineering' field due to the advantageous characteristics of ceramics and demands for glass machining from optical component manufacturers. In general the 'ductile mode' machining of brittle materials requires cut-geometry to be sub-micrometre. In order to improve machining accuracy of single-point diamond turning for brittle materials in the ductile mode, a controlled micro-tilt stage system was proposed for improvement of the motion accuracy and dynamic stiffness of an aerostatic spindle. Mechanical arrangements for the proposed controlled micro-tilt stage system including slip rings for transferring voltage signals to a rotating body were developed together with a strategy for spindle metrology using three optical fibre sensors. Algorithms for averaging and spacial filtering were applied to remove random noise caused by the variation of surface texture. The micro-tilt stage was designed to satisfy specifications in respect of travel range, resolution, stiffness, and resonant frequency. Efforts were also made to minimize static and dynamic cross-coupling-interference between the required three degrees of freedom. The micro-tilt stage showed satisfactory performance, and the effectiveness of non-crosscoupling design was seen. After considering various control strategies, hardware and software were arranged with PID and repetitive controllers. The diagonal dominance of the micro-tilt stage control system permitted 'SISO' system design. The performance of the controlled micro-tilt stage was investigated both stationary and during rotation. The stationary controlled micro-tilt stage worked satisfactorily; the controlled rotating micro-tilt stage demonstrated its error-correcting capability with some speed limitations, primarily due to the spacial filtering and time averaging required to reduce the surface texture noise.