David Hastie - Profile on Academia.edu (original) (raw)

Papers by David Hastie

The Investigation of Particle Flow Mechanisms of Bulk Materials in Dustiness Testers

Particulate Science and Technology, 2015

Investigation into segregation of bulk solids in storage bins

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In an effort to improve learning outcomes in a second year Engineering Fluid Mechanics subject, t... more In an effort to improve learning outcomes in a second year Engineering Fluid Mechanics subject, the first author has developed and piloted a series of online multiple choice quizzes (MCQ) as formative assessment tools. This paper describes the development and implementation of these quizzes and the evaluation of their effect on students' results in a formal written mid-session exam and also final exam. Students' perception of the quizzes is also captured and discussed through the use of a brief, in class survey. The effect of these MCQs was investigated for two main cohorts of students, those who voluntarily attempted the MCQs and those that did not participate at all. Student participation has been compared against mid-session and final examination results as well as Weighted Average Marks (WAM) (or Grade Point Averages (GPA)) and demographic information. It has been found that there was a noticeable increase in exam marks for students who attempted the MCQs. In addition, f...

Investigations into Pneumatic Conveying of Whiskas Pockets

Faculty of Engineering Papers, 2005

Characterisation of Suction Nozzle Feeders for Nickel Powder and Chips

Investigations into Aerobelt Conveyor Inclinations for Alumina

Conveyor transfer stations play a key role in many industries that handle bulk materials. Transfe... more Conveyor transfer stations play a key role in many industries that handle bulk materials. Transfer stations can be rather sensitive to changes in material properties and can lead to relentless problems regarding reliability, wear, bottlenecking and blockages. Wet and sticky ores are typically difficult to handle materials due to their obnoxious ability to form a cohesive arch, adhere to surfaces and poor flow ability. Mines that are situated in areas with seasonal high rainfalls or that have started to exploit newer and more difficult to mine and handle ores, often from below the water table, experience vast difficulty in reliably conveying and processing bulk material with such diverse flow ability over time. Mining and processing operations which add water into bulk solids for processing purposes also may experience handling issues further along the handling and processing line. Cohesive and adhesive effects of wet, sticky ore on transfer stations which contain impact plates, ledges and curved or straight chutes can make it difficult to design a system to reliably guide material in the direction of the receiving belt. Therefore, the usage of the discrete element method (DEM) to model the flow of cohesive and cohesionless materials through industrial transfer stations is increasing. This paper gives a short overview of the implementation of DEM to trouble-shoot and optimise a transfer station and shed some light on the strength and weaknesses of DEM. Some of the vital calibration techniques used to 'tune' the DEM material model using numerous bench-scale tests to produce representative flow behaviour of wet, sticky ores is also discussed.

Dense-phase is a specific form of pneumatic conveying, in which bulk solids are transported along... more Dense-phase is a specific form of pneumatic conveying, in which bulk solids are transported along a pipeline at relatively low conveying speeds. Slug-flow pneumatic conveying is a full-bore mode of flow within the dense-phase flow regime where granular materials are transported as plugs at conveying speeds generally below 5 m/s. Especially applications in the food and processing industry require conveying of fragile and brittle materials which makes this form of pneumatic conveying well suited due to its more gentle handling characteristics.

This paper explains the procedure used to determine the amount of air leakage expelled from two d... more This paper explains the procedure used to determine the amount of air leakage expelled from two different sized drop-through rotary valves. When designing a pneumatic conveying system, rotary valve air leakage may be overlooked, believed to be only a minor factor. This is somewhat true when conveying in dilute-phase where low pressures are generated, however in dense-phase pneumatic conveying where higher pressures can be produced, rotary valve air leakage can be a high proportion of the supplied air. Knowing the air leakage present for any given situation, the total supplied air mass flowrate can be adjusted to represent the actual air mass flowrate travelling through the conveying line, thus giving a more accurate representation of the actual conveying conditions. A series of tests have been performed from which a series of graphs have been produced. Comparisons have been made for the air leakage through the different sized rotary valves and also these results have been compared to two existing models used in the prediction of rotary valve air leakage.

Investigation of material properties and behaviour for DEM

Since the pneumatic conveying performance of granular materials in the transition zone between di... more Since the pneumatic conveying performance of granular materials in the transition zone between dilute-phase and dense-phase still lacks full understanding and assessment, especially the mechanism for the formation of unstable flow, tests have been carried out on poly pellets (particle diameter = 4.7 mm, particle density = 897 kg/m 3 ) and two different stainless steel pipelines (60.3 and 98.4 mm ID, each 21 m long). By careful observation and analysis of flow behaviours (covering dilute-phase, unstable zone and low-velocity slugflow), five different flow modes (as the air velocity is decreased): fully suspended flow; strand flow; stable or unstable strand flow over a stationary layer for low solid mass flow rates; strand flow over a slowly moving bed for high solid mass flow rates; low-velocity slug-flow are identified. The mechanism involved in the formation of unstable zone was explored.

Investigation of material properties and behaviour of coal for DEM

Researching conveyor belt trajectories

Nonintrusive Monitoring of Slug Sequence and Flow Stability in Dense-Phase Pneumatic Conveying

Particulate Sci Technology, 2007

This article presents three sensing methods developed for the nonintrusive monitoring of importan... more This article presents three sensing methods developed for the nonintrusive monitoring of important flow parameters in dense-phase pneumatic conveying. With the optical measurement system, images of the flow are acquired and an image analysis is used to determine the sequence, length, and velocity of slugs for given materials and operating conditions. The conveying parameters of interest are also monitored with a capacitive sensor by means of exploiting electrical properties of the flowing media. The charge-based measurement system uses a field meter to determine the electric field strength caused by charged particles and provides information about the sequence and regularity of the moving slugs. The noninvasive principle of all three methods avoids concerns about particle contact effects (e.g., wear of the measurement equipment or interference with the flow). All three prototype sensors have been tested under slug flow conditions. A comparison of the three sensing methods against key requirements in pneumatic conveying reveals that capacitive sensing seems to be best suited for reliable flow determination in slug flow.

Remote monitoring of slug sequence and flow stability in Dense-Phase Pneumatic Conveying

Monday, 24 April 2006 - 9:40 AM 12f. Remote Monitoring of Slug Sequence and Flow Stability in Den... more Monday, 24 April 2006 - 9:40 AM 12f. Remote Monitoring of Slug Sequence and Flow Stability in Dense-Phase Pneumatic Conveying. Anton Fuchs 1 , Peter W. Wypych 2 , David B. Hastie 2 , and Ian Frew 2 . (1) Institute of Electrical ...

Dense-Phase Conveying Suitability and Performance of Enriched Alumina

This paper presents results from an investigation into power-function modelling of solids frictio... more This paper presents results from an investigation into power-function modelling of solids friction factor for the dilute-phase and fluidised dense-phase (FDP) conveying of powders. Three different diameters/lengths of pipeline were used to generate a wide range of steady-state data and also explore important scale-up issues. The effect of pressure tapping locations on the data and derived models was also investigated. Different sets of power-function model solutions were used for comparison purposes and also to check scale-up stability and accuracy. Comparisons with predictions from recent models developed by other researchers are included.

2014 IEEE International Conference on Industrial Engineering and Engineering Management, 2014

Online course delivery can not only help meet the increasing flexibility demanded by students, bu... more Online course delivery can not only help meet the increasing flexibility demanded by students, but also enhance collaborative learning. Moreover, online delivery allows access to students and markets that are not served through the traditional face-to-face delivery mode. Despite these potential benefits, and the opportunities created by the advancements in information and communications technologies, there are still many barriers to the market penetration of online education programs. This paper explores the implications of learning theories, pedagogical aspects and other contingency factors for instructional design in the context of online delivery of tertiary courses. A synthesis of extant knowledge pertaining to these perspectives is presented in the form of an integrated conceptual framework for guiding future work.

R&D of Bypass Conveying System for Coffee Creamer Powder