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By Min Chen, Qinghua Liang, Weishan Yan, Yuan Feng, Shigang Wang

Various coal mine robots (CMRs) and unmanned aerial vehicles (UAVs) are implemented to explore unknown mines for improving the safety and efficiency of mining. It is challenging for CMRs and UAVs to achieve accurate positioning due to the absence of GPS, poor lighting conditions, and similar geometric features in complex mine scenes. LiDAR-based localization and mapping methods are admittedly more accurate than others, while long-time running in large-scale scenarios will also introduce non-negligible cumulative errors. This study presents a semantic-aided LiDAR simultaneous localization and mapping (SLAM) with loop closure, which leverages the uniqueness of mine intersection structure to establish stable semantic loop closure. Specifically, we propose a semantic intersection descriptor of translation and rotation invariance, which encodes 3D point clouds of the same intersection from different positions and viewpoints into a unified image. By using the semantic descriptor, we can construct a constant loop constraint when the same intersection is revisited from different directions to reduce cumulative drift. We provide experimental validation using large datasets collected in two large underground mines, namely, a simulated Edgar mine deployed in ROS Gazebo and a public underground mine dataset provided by ETH. Experimental results show that the proposed method has higher localization accuracy and outperforms the existing LiDAR-based SLAM strategies.

Aug 10, 2023

By Ian Orford, Ken L. Boyd

"Can the ever-increasing tonnages of ore and waste being mined today be accommodated simply by using bigger and better crushers? This paper updates the principal author’s earlier publication, “Crushing Plant Design and Layout Considerations” (SME Mineral Processing Plant Design, Practise, and Control, 2002). It reviews the latest primary crushing and large cone crusher designs. Its goal is to help consultants and operators select the optimal equipment and custom-designed items in the material handling flowsheet from the mine to the mill, maximizing operating hours per year.INTRODUCTIONAre larger crushers the answer to meeting the demands of existing or new mining projects for increased tonnage? The principal author’s previous paper in the year 2002 on ""Crushing Plant Design and Layout Considerations"" provided a detailed design and layout review for the design of primary and fine crushing (Secondary, Tertiary, Quaternary) mineral processing facilities. Some of the conclusions in this previous paper had predicted that larger crushers for primary and fine crushing would be beneficial and contribute to the further development of mineral processing. Larger crushers for primary and fine crushing applications are now available.The rock size reduction process, from the mine to the selected milling process facility has not changed since man first broke a rock to get at the interesting mineralization within. The rock size reduction process circuit from the mine to the mill can be summarized into four (4) stages:• Stage 1: Mining ( Rock Breakage and Fragmentation)• Stage 2: Pre-Screening (Scalping)• Stage 3: Primary Crushing• Stage 4: Fine Crushing (Secondary, Tertiary and Quaternary; the crushers used in this stage are identified by the titles which usage has conferred on them)Plant throughput and ore delivery schedule will form the basis for flowsheet design and equipment selection. Once a project's design criteria and the mine plan has been established, the actual circuit's utilization percentage (percentage of hours when the circuit is being utilized) can be optimized for each of the four stages. The mining and process departments are the key stake holders in the selection of the final comminution circuit and both departments should be familiar with and contribute to the design of the circuit."

Jan 1, 2016

By K. L. Boyd

"Can the increasing tonnages of ore and waste mined today be accommodated simply by using bigger and better crushers? This paper reviews the latest primary crushing and large cone crusher designs. It highlights how—in addition to using the larger crushers now available—maximizing the utilization percentages in each stage of the rock size reduction circuit will assist in meeting the larger production requirements of existing and new mining operations. Its goal is to help consultants and operators select the optimal equipment and custom-designed items in material handling from the mine to the mill, maximizing operating hours per year.RÉSUMÉ Le recours à des concasseurs plus grands et plus performants suffit-il à gérer l’augmentation du tonnage du minerai et des déchets que l’on extrait de nos jours ? Cet article examine les tous derniers modèles de concassage primaire et de grands concasseurs à cône. Il montre que, pour satisfaire aux exigences de production plus conséquente des exploitations minières existantes et nouvelles, il est important d’optimiser les taux d’utilisation à chacune des étapes du circuit de réduction de la taille des roches, en plus d’utiliser les concasseurs plus grands actuellement disponibles. L’objectif de cet article est d’aider les sociétés d’experts-conseils et les exploitants à sélectionner le meilleur équipement ainsi que des articles fabriqués sur mesure pour la manutention de la mine au concentrateur, en optimisant les heures d’exploitation par année.INTRODUCTIONAre larger crushers the answer to meeting the demands of existing or new mining projects for increased tonnage? Boyd (2002) predicted that larger crushers for primary and fine crushing would be beneficial and contribute to the further development of mineral processing. Larger crushers for primary and fine crushing applications have since become available.The rock size reduction process from the mine to the selected milling process facility has not changed since a person first broke a rock to get at the interesting mineralization within. The rock size reduction process circuit from the mine to the mill can be summarized in four stages:• stage 1: mining (rock breakage and fragmentation);• stage 2: prescreening (scalping);• stage 3: primary crushing; and• stage 4: fine crushing (secondary, tertiary, and quaternary).Plant throughput and ore delivery schedule will form the basis for flowsheet design and equipment selection. Once the project design criteria and the mine plan have been established, the circuit’s utilization percentage (percentage of hours when the circuit is being utilized) can be optimized for each of the four stages. The mining and process departments play a key role in the selection of the final comminution circuit, and both departments should be familiar with and contribute to the design of the circuit."

Jan 1, 2017

By K. L. Boyd

"Can the ever-increasing tonnages of ore and waste being mined today be accommodated simply by using bigger and better crushers? This paper reviews the latest primary crushing and large cone crusher designs. It highlights how—in addition to using the larger crushers now available—maximizing the utilization percentages in each of the four stages of the rock size reduction circuit will assist in meeting the larger production requirements of existing and new mining operations. Its goal is to help consultants and operators select the optimal equipment and custom-designed items in the material handling flowsheet from the mine to the mill, maximizing operating hours per year. INTRODUCTION Are larger crushers the answer to meeting the demands of existing or new mining projects for increased tonnage? Boyd (2002) predicted that larger crushers for primary and fine crushing would be beneficial and contribute to the further development of mineral processing. Larger crushers for primary and fine crushing applications are now available. The rock size reduction process from the mine to the selected milling process facility has not changed since man first broke a rock to get at the interesting mineralization within. The rock size reduction process circuit from the mine to the mill can be summarized in four stages: • Stage 1: Mining (rock breakage and fragmentation) • Stage 2: Pre-screening (scalping) • Stage 3: Primary crushing • Stage 4: Fine crushing (secondary, tertiary and quaternary) Plant throughput and ore delivery schedule will form the basis for flowsheet design and equipment selection. Once the project design criteria and the mine plan have been established, the circuit’s utilization percentage (percentage of hours when the circuit is being utilized) can be optimized for each of the four stages. The mining and process departments are the key stakeholders in the selection of the final comminution circuit, and both departments should be familiar with and contribute to the design of the circuit. This paper focuses on the four stages of a rock size reduction circuit from the mine to the mill, equipment selection, various ore and waste handling flowsheets, and improvements in crusher station design, all with the purpose of maximizing availability and plant utilization percentages. What is a large tonnage? From 1907 to 1914, the American Panama Canal excavated 300 million tonnes of material in 7 years (History of the Panama Canal, Wikipedia). Today’s large mining operations can move the same material in 10 months, using large crushers or multiple crushers for ore processing and large crushers and a mixture of truck haulage and conveyors for handling the large waste tonnages. Some examples include:"

Jan 1, 2017

By AIME AIME

IN times of stress nations pick strong men to lead them. Similarly the Coal Division selected forceful Larry A. Shipman, fuel engineer for the Southern Coal and Coke Co., Knoxville, Tenn.. to lead it through the year 1945. He was born in Indianapolis May 13, 1891. Following graduation from a technical high school in that city Larry began his fuel career approximately 35 years ago attached to one end of a scoop shovel, firing locomotives for the Pennsylvania Railroad. At the end of two years he transferred to the New York Central Lines and held these jobs successively: locomotive fireman, engineer, fireman instructor, supervisor of instructors, and fuel engineer.

Jan 1, 1945

By W. C. Schafer

In tunneling or mining where hydraulic shields, moles, or rock boring equipment is used lasers such as those shown guide the production machine by providing a continuous and visible line and grade reference. In this application the laser may be mounted in the heading, preferably somewhere above spring line. If we view the circular heading as a compass in the vertical plane with 0º referencing at the crown of the heading and 180º on the invert, then it might be said that the laser may be mounted anywhere from 270º through 0º to 90º. The laser is generally mounted 2 to 3 ft off the wall or the crown of the heading by means of a bracket that may be attached directly to the liner plate. In cases where no liner plate is used, then brackets may be bolted directly into the ribs, or grouted directly into the rock. Once the laser is in position the beam is projected to the face. Two points must be surveyed upstream between the laser and the face which define line and grade. Targets may be suspended beneath each of these points approximately 2 to 3 ft. These targets may be circular or rectangular with a surface area which approximates 16 sq in. Each of these two targets should have a ½ to ¾ in. hole drilled directly in their center. When the laser is adjusted so that the beam passes through the holes in each of the two targets, the laser beam itself will parallel the center line of the tunnel and become a visible line and grade reference over the total beam projection.

Jan 1, 1970

By J-M Huizenga, Q Shu, Y Lai, J Hammerli

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Baiyinnuo’er Zn-Pb deposit is a typical skarn deposit in NE China. Skarn and orebodies mainly occur between different units of the Lower Permian Huanggangliang Formation carbonates-sandstone-mudstone or within the contact between intrusions and marble. Skarn minerals are dominated by prograde garnet and clinopyroxene, and the main ore minerals are sphalerite and galena. We conducted single fluid inclusion compositional studies using laser ablation inductively coupled plasma mass spectrometry on clinopyroxene (pre-ore-stage mineral) and sphalerite and calcite (syn-ore-stage minerals). The results show that the Baiyinnuo’er fluids are distinctly different from basinal brine but similar to magmatic fluid, thereby indicating that the deposit has a dominantly magmatic origin. This interpretation has also been supported by the Cl/Br mole ratios, which remain stable (~500) in different fluid stages. The decreases for most of the elements in the fluid inclusions from pre-ore-stage clinopyroxene to syn-ore-stage sphalerite and calcite suggest that mixing with groundwater has occurred during mineralisation, with significant Zn, Pb and Ag deposition.CITATION:Shu, Q, Hammerli, J, Chang, Z, Lai, Y and Huizenga, J-M, 2015. Laser ablation inductively coupled plasma mass spectrometry study on fluid inclusions of the Baiyinnuo’er skarn Zn-Pb deposit, north-east China, in Proceedings PACRIM 2015 Congress, pp 451–456 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Liangju He, Peixuan Ouyang, Peijie Li

Single-pulse laser ablation of aluminum and titanium alloys under glass confinement is investigated. Processing parameters such as laser intensity and gap width between targets and glass are varied. Surface morphologies and crater profiles of the alloys after laser ablation are studied by SEM and white-light interferometric microscope, respectively. The effects of gap width and laser intensity on surface morphologies and crater profiles of targets are systematically analyzed. In addition, the generation of porous surface structures in Ti target is regarded as the result of phase explosion in the molten surface layer of targets and the thermodynamic condition in our experiment for phase explosion is evaluated.

Jan 1, 2016

By E. Alan Haley

Accurate and economic control of line and grade on long tunnels, large structures, excavations and waterways, has been a problem to surveyors and engineers for decades. The conventional method of surveying, incorporating a level, transit, and a number of surveying technicians, has proven, in the past, to be a very expensive and time-consuming operation. Alignment with a laser has solved most of the problem. Figure 1. With the advent of the Perkin-Elmer Model 5620 Construction Laser, use of laser light is now both dependable and economically feasible for unlimited applications in modern construction and surveying. The laser projects a continuous, narrow red beam of brilliant light, providing a constant alignment reference, and will not interfere with operations.

Jan 1, 1968

By E. Alan Haley

Accurate and economic control of line and grade on long tunnels, large structures, excavations and waterways has been a problem to surveyors and engineers for decades. The conventional method of surveying, incorporating a level, transit and a number of surveying technicians, has proven to be a very expensive and time-consuming operation. Now, however, engineers have adapted the laser to help ease the problems of surveying, at the same time increasing the efficiency of such operations. The laser, which projects a continuous, narrow red beam of brilliant light, provides a constant alignment reference that does not interfere with personnel or equipment. A complete laser alignment system, specifically designed for and suited to a variety of mining and tunneling operations, has been developed by the Perkin-Elmer Corp. The engineering significance of this development can be fully realized when it is noted that, aside from potentially tremendous economic advantages in terms of labor savings, the laser beam provides a system of alignment that is at least ten times more accurate than presently used optical systems. The new laser system provides accuracies within 10 microinches per foot (1 x 10-5in.) when used with an accessory centering detector. In one of its first field trials, the laser was used for alignment of a two-mile tunnel which showed a total deviation of less than 5/8 in.

Jan 4, 1968

By K. J. Kruger

Aluminium alloys have gained popularity in many industries due to their high strength and low weight. One shortcoming of aluminium alloys is their poor resistance to abrasion and erosion wear compared to materials such as stainless steels. In this project, aluminium alloy 2014 (AA2014) was coated with a 1.5 mm thick laser-deposited layer composed of silicon, copper, and aluminium with the aim of increasing the wear resistance. The amount of silicon, copper, and aluminium added to each sample was determined by a mixtures model. It was discovered that the Al-Cu system is very sensitive to silicon additions and that wear resistance depends on the primary phase to solidify as well as on the final phase distribution. Two primary phases were identified; alpha aluminium and theta intermetallic. It was observed that the clad layer increases both the hardness and wear resistance of AA2014, and that the material solidifying as primary alpha aluminium displayed a lower hardness but higher wear resistance than the samples containing primary theta phase. All clad layers performed better in terms of wear resistance than the unclad samples. The knowledge gained and principles used in this project could be applied to many other aluminium alloys.

Jan 1, 2014

By D. M. S. Bhatia

Five sulfide minerals from the Magiwnt mine, southeast Missouri were analyzed for 31 trace elements in over 300 samples by laser microprobe spectrographic analysis of polished sections. The concentration of several trace elements shows a pattern of progressive variation with depth (space) and variation with different paragenetic stages (time) of each mineral. Factor analysis of the geochemical data shows sympathetic correlation both in space and in time of Bi, Cd, Ge, and Sn in galena and sphalerite, and Ni and Co in sphalerite and marcasite.

Jan 1, 1979

By S Grobler, T Fares

Understanding the real utilisation of the available volumetric capacity of a conveyor is key to unlocking latent capacity or ‘debottlenecking’ existing plant. Conveyors are typically designed on the basis of conservative density and ore surcharge angle specifications, and consequently there is often latent volumetric capacity available.Laser scanning measurements of conveyor ore profiles has been undertaken on iron ore conveyors to gain an understanding of the actual surcharge angle and the available edge clearances. Iron ore producers seeking to extract maximum production from their assets have used these measurements to debottleneck existing plant and to revise the design criteria for future plant. The benefit is that latent capacity of existing plant can be unlocked and smaller and cheaper conveyors can be designed for future plant, maximising the return on capital. This paper describes the measurements and results.CITATION:Fares, T and Grobler, S, 2015. Laser scanning of conveyor ore profiles, in Proceedings Iron Ore 2015, pp 549–554 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By N. Baloyi, P. Popoola, M. Tlotleng, S. L. Pityana

"The advantages of using Nb and Ti-Nb coatings for improving the hardness and corrosion resistance of Ti6Al4V were investigated. It has been reported that Ti6Al4V used in orthopaedic implants tends to release toxic Al and V ions into the surrounding tissue. Thin layers of Nb and Ti-Nb were deposited on Ti6Al4V substrates using a laser metal deposition technique. The deposited material was analysed using optical microscopy, scanning electron microscopy coupled with energy dispersive spectroscopy, and X-ray diffraction. The corrosion behaviour of the deposited layers was investigated using a Metrohm Autolab PG Stat101 compact potentiostat at 25°C in simulated body fluid. A Vickers hardness system was used to study the mechanical properties. Both Nb and Ti-Nb coatings exhibited good metallurgical bonding with the substrate. The microstructure and the XRD analyses for the Nb system showed that the ??-Nb phase was most dominant, while the Ti-Nb system comprised a mixture of the ?? and ?? phases. The average hardness of the Ti6Al4V substrate was 350 HV0.3, with a slight increase for the Nb coating (363 HV0.3) and a much higher hardness from the Ti-Nb coating at 423 HV0.3. The corrosion results show that the deposited Nb was more corrosion-resistant in the solution than either the Ti6Al4V substrate or the Ti-Nb coating. IntroductionMetals such as CoCrMo, 316L stainless steel, and NiTi alloy are used for manufacturing biomedical implants because of their distinct properties, including low Young’s modulus and resistance to corrosion (Ryan, Pandit, and Apatsidis, 2006). These implants are required to remain in the body of the patient for many years. Due to a favourable combination of mechanical and corrosion properties, titanium (Ti) and its alloys have emerged as the material of choice for biomedical implants. Nevertheless, their use is not entirely without challenges. For example, in total hip replacement, surface degradation and release of metal debris from metal erosion caused by friction limit the service life of the implant (Oldani and Dominguez, 2012; Manivasagam, Dhinasekaran, and Rajamanickam, 2010). Ti6Al4V is generally regarded as the material of choice, but it has been found that over extended periods of time, the combination of surface corrosion and erosion releases toxic aluminium (Al) and vanadium (V) ions into the body (Khan, Williams, and Williams, 1996). This has led to the investigation of titanium alloys containing niobium (Nb), zirconium (Zr), tantalum (Ta), and molybdenum (Mo) as substitutes for the aluminium- and vanadium-containing Ti6Al4V (Okazaki et al., 1997)."

Apr 1, 2019

By Nathaniel R. Quick

"Nd: YAG, KrF excimer, and Cu-vapor lasers are used in air to synthesize conductors and semiconductors as a second phase in silicon carbide and aluminum nitride. Conductor resistivities as low as 104 O-cm are formed in these substrates; the resistivities for the untreated substrates range from 10 11to 1014 O-cm. The silicon carbide conversion is relatively independent of wavelength while the aluminum nitride conversion shows a dependence on wavelength over the range 248 nm to 1064 nm. Silicon carbide conductors, evaluated over the range 15 K to greater than 300 K, exhibit metal like conductivity; resistivity increases with temperature. Silicon, carbon, and oxygen are identified as the principal chemical species associated with the conductor in SiC substrates while aluminum, nitrogen, and oxygen are identified as the principal chemical species associated with the conductor in aluminum nitride substrates. The silicon carbide system, which has the less complex phase diagram, is evaluated in more depth to explain the synthesis mechanism. Oxygen was principally on the surface and increasing SiC conductivity is associated with decreasing spacing between 5 µm, or less, diameter carbon globules. This technology is proposed as a replacement for metallization in electronic packages, sensors and devices. INTRODUCTIONCeramics are commonly used for multichip module, hybrid and multilayer electronic packaging; semiconductor device and sensor applications because of the insulating, conducting, semiconducting, or superconducting properties that these materials possess (1,2) The majority of ceramics, however, have not been known to exhibit conductive or semi conductive properties when exposed to rapid thermal heat processing. A ceramic and process which through selective conversion can combine two or more of these electrical properties to eliminate the need for metallization is of interest to both the commercial and military sectors."

Jan 1, 1994

By Yichi Lu, Haydn N. G. Wadley, Douglas T. Queheillalt

"Using a 3-D ray tracing methodology combined with laser ultrasonically measured elastic constant data near the melting point, ultrasonic propagation in cylindrical single crystal bodies containing either a convex or a concave solid-liquid interface have been simulated and used to design new sensing concepts. Ray paths, wavefronts and time-of-flight (TOF) of rays that travel from a source to an arbitrarily positioned receiver have been calculated. Experimentally measured TOF data have been collected using laser generated/detected ultrasound on model systems with independently known interface shapes. Both numerically simulated data and experimental results have shown that the solidification (interfacial) region can be identified from ultrasonic transmission TOF data. Since convex and concave solid-liquid interfaces result in distinctively different TOF data. When TOF data collected in the diametral plane are used in a nonlinear least squares algorithm, the interface curvature has been successfully reconstructed and ultrasonic velocities of both the solid and liquid obtained. The reconstruction errors were found to be less than 5%.IntroductionMany of today's single crystal semiconductors are grown by variants of a vertical Bridgman technique in which a cylindrical ampoule of a molten semiconductor is translated through a thermal gradient, resulting in directional solidification and the growth of a single crystal, Fig. 1.1 It has long been recognized that during crystal growth the velocity and the shape of the solid-liquid interface, together with the local temperature gradient, control the mechanism of solidification (i.e. planar, cellular or dendritic), the likelihood of secondary grain nucleation/ twin formation (i.e. the loss of single crystallinity), solute (dopant) segregation, dislocation generation, etc. They thus determine the crystals' resulting quality.2-4 The solidification rate and the solid-liquid interface shape are also sensitive functions of the internal temperature gradient (both axial and radial) during solidification.5•6 This in turn is governed by the heat flux distribution incident upon the ampoule, the latent heat release at the interface, and heat transport (by a combination of conduction, buoyancy and surface tension driven convection, and radiation) within the ampoule. The solid-liquid interface's instantaneous position, velocity and shape during crystal growth are therefore difficult to predict and uncontrolled during growth, especially for those semiconductor materials with low thermal conductivity (e.g. CdTe).4-6 The development of technologies to non-invasively sense the interface position and shape throughout the vertical Bridgman crystal growth process has therefore become a key step toward developing a better understanding of the growth process, for enabling sensor-based process control, and thus ultimately for improving the yield and quality of difficult to grow semiconductor materials like CdTe."

Jan 1, 1997

Track and control the tram maneuvers of continuous mining machines by developing and evaluating a laser sensor system. Background Progressive technology has the potential to greatly improve mine-worker safety, helping to create a safer, better working environment for mine workers by keeping them away from the dangerous face area. To benefit from such technology, the Bureau is investigating remote, computer-assisted operation of mining systems for underground, highwall, and surface mining applications. A cornerstone for computer-assisted operation is an effective guidance system. Since there are no guidance systems on any commercial continuous miners (CM's), the Bureau it-self developed and tested a laser-based sensor system, based on a commercial sensor called Lasernet. The laser-based guidance system employs four laser scanning sensors at fixed locations in a mine entryway to report the angular coordinates of two cylindrical retro-reflective targets mounted on a CM. Using triangulation, a real-time microcomputer system processes the sensor data and updates the xy position and heading (h) of the CM five times per second. Using a simple control algorithm and communications interface to the CM control computer, the system also controls rotational and translational tram maneuvers.

Jan 1, 1992

By Heikki Häkkänen, Tommi Kauppinen, Navid Khajehzadeh

"There are a variety of methods suitable to analyse elemental and mineralogical contents of rock drill core samples. Current demands are on fast exploration and objective analysis of ore samples. This paper proposes a combination of Laser-Induced Fluorescence (LIF) and image processing, entitled LIF-imaging, as a potential method for automated mineral analysis of the drill core samples. It is shown that LIF-imaging can produce a mineral map of the fluorescent minerals existing on the surface of the drill core samples. The test cases are drill core samples from a Ni-Cu mine situated in Kevitsa, Finland. The main prerequisite of LIF-imaging technique is a reference data, linking colours to the minerals. This study describes the calibration of LIF-imaging technique using precise but slow Raman spectroscopy. Using regularized logistic regression, a model is obtained that classifies the minerals based on their emitted fluorescent colours in the digital images. The abundance of each mineral group is estimated by pixel counting. The results are compared with X-Ray Diffraction laboratory assays performed on the same samples. The results show that the interpretation of the fluorescent minerals through LIF images corresponds to the XRD results. Furthermore, the utilization of the logistic regression to interpret the existing fluorescent minerals greatly improves the technique."

Jan 1, 2014

By AIME AIME

ALL technical men who are planning to visit the Century of Progress Exposition in Chicago this summer-and all reports indicate that it will be worth visiting-should try to be there during Engineers' Week, beginning June 26. At that time most of the national engineering societies of the country will hold important meetings in that city. Engineers will thus have an opportunity not only to see the Fair at a time when special programs have been arranged for their benefit, but will have the opportunity to meet their professional brothers and to attend technical sessions of direct interest to them. The A.I.M.E. headquarters will be at the Stevens Hotel, and it will be to the interest of every Institute member who expects to attend the Fair at that time to secure his accommodations as promptly as possible. A request to the Chairman of the Chicago Section, A.I.M.E., or to the Secretary's office in New York, will bring a copy of the program as soon as it is available, together with any in- formation desired about hotel accommodations or other matters. The Chairman of the Chicago Section is J. R. Van Pelt, and his address is Museum of Science and Industry, 1525 East 53rd St., Chicago.

Jan 1, 1933

By Carlos Gonzalez-Rivera

An alternative cooling curve analysis method focused on the experimental determination of the latent heat of phase changes and phase transformation kinetics is proposed in this work. The method analyses the cooling process of a metallic sample, initially liquid that is contained into a cylindrical metallic mold, both of known weight, thermally isolated at its top and bottom. The method is based on an energy balance associated with the experimental measurement of the temperature change of the sample and the mold during their cooling process. From the numerical processing of the cooling curves, are obtained approximate values of the acting global heat transfer coefficient as a function of temperature in order to describe quantitatively the energy exchange of the metal/mold system with its surroundings. These relationships and other experimental data are used to process the cooling curve of the sample and the mold during solidification, in order to obtain the latent heat of solidification.The method was applied experimentally to zinc and tin of commercial purity, initially liquids and contained into stainless steel molds in order to determine its ability to measure the latent heat of solidification. The obtained results suggests that this method shows a good potential to characterize the solidification of metals.

Oct 30, 2017