Mass flow meter using the triboelectric effect for measurement in cryogenics

The use of triboelectric charge to measure the mass flow rate of cryogens for the Space Shuttle Main Engine was investigated. Cross correlation of the triboelectric charge signals was used to determine the transit time of the cryogen between two sensor locations in a .75-in tube. The ring electrode sensors were mounted in a removable spool piece. Three spool pieces were constructed for delivery, each with a different design. One set of electronics for implementation of the cross correlation and flow calculation was constructed for delivery. Tests were made using a laboratory flow loop using liquid freon and transformer oil. The measured flow precision was 1 percent and the response was linear. The natural frequency distribution of the triboelectric signal was approximately 1/f. The sensor electrodes should have an axial length less than approximately one/tenth pipe diameter. The electrode spacing should be less than approximately one pipe diameter. Tests using liquid nitrogen demonstrated poor tribo-signal to noise ratio. Most of the noise was microphonic and common to both electrode systems. The common noise rejection facility of the correlator was successful in compensating for this noise but the signal was too small to enable reliable demonstration of the technique in liquid nitrogen

Autonomous control of underground mining vehicles using reactive navigation

Describes how many of the navigation techniques developed by the robotics research community over the last decade may be applied to a class of underground mining vehicles (LHDs and haul trucks). We review the current state-of-the-art in this area and conclude that there are essentially two basic methods of navigation applicable. We describe an implementation of a reactive navigation system on a 30 tonne LHD which has achieved full-speed operation at a production mine

Discovery of halloysite books in altered silicic Quaternary tephras, northern New Zealand

Hydrated halloysite was discovered in books, a morphology previously associated exclusively with kaolinite. From ~1.5 μm to ~1500 μm in length, the books showed significantly greater mean Fe contents (Fe2O3 = 5.2 wt%) than tubes (Fe2O3 = 3.2 wt%), and expanded rapidly with formamide. They occurred, along with halloysite tubes, spheroids, and plates, in highly porous yet poorly-permeable, silt-dominated, Si-rich, pumiceous rhyolitic tephra deposits aged ~0.93 Ma (Te Puna tephra) and ~0.27 Ma (Te Ranga tephra) at three sites ~10-20 m stratigraphically below the modern land-surface in the Tauranga area, eastern North Island, New Zealand. The book-bearing tephras were at or near saturation, but have experienced intermittent partial drying, favouring the proposed changes: solubilized volcanic glass + plagioclase -> halloysite spheroids -> halloysite tubes -> halloysite plates -> halloysite books. Unlike parallel studies elsewhere involving both halloysite and kaolinite, kaolinite has not formed in Tauranga presumably because the low permeability ensures the sites largely remain locally wet so that the halloysite books are metastable. An implication of the discovery is that some halloysite books in similar settings may have been misidentified previously as kaolinite

Bulk analysis of lead smelter sinter plant products for sulphur (and Pb, Fe, Zn) using neutron inelastic scatter gamma-rays

A potential for increasing the production in the lead sinter plant at Mount Isa exists if the sulphur and moisture concentration in the feed material could be controlled accurately. This thesis reports on a project to develop an on-line instrument to measure sulphur and moisture in sinter feed for process control. The feasibility of measuring the concentrations of lead, iron and zinc is also examined. The instrument uses the technique of fast neutron inelastic scatter gamma ray measurement for the element determinations and neutron moderation for moisture measurement. Three instrument geometries were examined under laboratory conditions:- (a) annular (b) semi-annular (c) backscatter - main layer (d) backscatter - ignitor layer An instrument based on geometry (c) constructed and tested in the laboratory. above, was designed, The instrument was shown to measure sulphur, lead, iron, zinc and moisture to within (one standard deviation) O. 67, 1.2, 0.49 and 0.34 and 0.49 -weight 1.respectively. The repeatability for a aeasurement time of 25 minutes was 0.40, 0. 70, 0.20, 0.17, 0.3 weight 1. respectively. This performance is adequate for process control

The Application of wireless LANS in mine automation

The objective of this paper is to provide an overview of mine automation applications, developed at the Queensland Centre for Advanced Technology (QCAT), which make use of IEEE 802.11b wireless local area networks (WLANs). The paper has been prepared for a 2002 conference entitled "Creating the Virtual Enterprise - Leveraging wireless technology within existing business models for corporate advantage". Descriptions of the WLAN components have been omitted here as such details are presented in the accompanying papers. The structure of the paper is as follows. Application overviews are provided in Sections 2 to 7. Some pertinent strengths and weaknesses are summarised in Section 8. Please refer to http://www.mining-automation.com/ or contact the authors for further information

Mining robotics

Mining is the process of extracting mineral resources from the Earth for commercial value. It is an ancient human activity which can be traced back to Palaeolithic times (43 000 years ago), where for example the mineral hematite was mined to produce the red pigment ochre. The importance of many mined minerals is reflected in the names of the major milestones in human civilizations: the stone, copper, bronze, and iron ages. Much later coal provided the energy that was critical to the industrial revolution and still underpins modern society, creating 38% of world energy generation today. Ancient mines used human and later animal labor and broke rock using stone tools, heat, and water, and later iron tools. Today’s mines are heavily mechanized with large diesel and electrically powered vehicles, and rock is broken with explosives or rock cutting machines