Study Group Problems
Problem 1: STORAGE OF SUGAR CANE BAGASSE
Industry: Sugar Cane Processing
Industrial Representative:Richard Loubser, Sugar Milling Research Institute, University of KwaZulu-Natal.
Moderator:
Student Moderator:
Problem Statement:
Co-generation of electricity will provide an additional income source for the sugar industry. Energy for sugar processing is derived from burning bagasse, the fibrous residue that remains after the sugar has been extracted from the shredded sugar cane. Any excess bagasse can be burned to produce electricity which can be exported to the grid.
Sugar cane is not harvested for the whole year so factories shut down during the off-crop. It would not be attractive to only produce electricity for part of the year. Bagasse needs to be stored so that it can be burned during the off-crop to generate electricity all year round.
After the extraction process, the fibre from the cane is squeezed in a drying mill. This gives a final moisture of approximately 50%. There have been reports that if the bagasse is stacked in this state, the heating effect of microbial activity can lead to spontaneous combustion. The literature suggests that the likelihood of spontaneous ignition depends on factors such as moisture content, fermentable sugar content, oxygen availability, packing density and stack height.
Adjusting the moisture content has consequences in terms of energy loss. If the moisture content is increased prior to storage then this needs to be evaporated when the bagasse is burned in the boiler, that is, the net calorific value is reduced. Reduction of moisture requires energy to evaporate the water before the bagasse is stored.
Pelletising the bagasse has been suggested as an alternative to bulk stacking. To do this, the bagasse needs to be dried to 20% moisture, ground into smaller particles and then heated under pressure to cause it to bond into pellets. This process consumes some of the energy which would otherwise be available for electricity.
Questions to consider:
- Is there an optimum/maximum height to avoid spontaneous combustion?
- Will there be an advantage in adjusting the moisture content in terms of usable energy stored per unit area per unit cane?
- Will there be an advantage in pelletising the bagasse in terms of usable energy stored per unit area per unit cane?
Presentations
Storage of Sugar Cane Bagasse - Richard Loubser
Solutions
Problem 2: ROCK STRENGTH, ROCK BRITTLENESS AND BLAST FRAGMENTATION
Industry: Mining Industry
Representative: Richard Stacey, School of Mining Engineering, University of the Witwatersrand, Johannesburg.
Moderator:
Student Moderator:
Problem Statement:
Rock fragmentation by blasting is usually “tougher” for stronger rocks, resulting in an increase in fragmentation size with rock strength. The references to Cunningham are relevant in this regard. Contrary behaviour was recently experienced for an extraordinarily strong rock: a far greater percentage of fines occurred than was expected, and investigations were carried out in an attempt to explain this. It appeared that the fragmentation experienced could be related to both the strength and the brittleness of the rock. However, there was little information linking brittleness to fragmentation, and there are about 30 different definitions of brittleness. This perhaps explains the lack of a well-understood link between fragmentation and blasting.
The higher the rock strength, the greater the amount of energy contained in the rock at its peak strength, and therefore it could perhaps be expected that there should be a correlation between fragmentation resulting after failure of rock specimens, whether in uniaxial compression strength (UCS) tests or in small scale blasting tests.
Read the full problem statement
Background reading:
Universal criteria for rock brittleness estimation under triaxial compression
The Kuz-Ram fragmentation model – 20 years on
Super brittleness of rocks and earthquake activity
Presentations
Rock strength Rock brittleness and blast fragmentation - Richard Stacey
Soultions
Rock strength Rock brittleness and blast fragmentation
Problem 3: AIR TRAFFIC FLOW MANAGEMENT REROUTING PROBLEM
Industry: Air transport
Industrial Representative: Alex Somto Alochukwu
Moderators: Aderemi Oluyinka Adewumi, University of KwaZulu Natal and Montaz Ali, University of the Witwatersrand
Student Moderator:
Preamble:
The air transportation industry has experienced rapid growth in recent times and the demand for airport and airspace usage increases exponentially as the number of users increase. Moreover, congestion problem abounds almost on a daily basis as a result of bad weather conditions and other unforeseen factors. This has a serious effect and impact on the Air Traffic Control System as well as the nation's economy due to the significant costs incurred by the airlines and passengers arising from the flight delays. Hence, the need for efficient and safe air traffic flow management that mitigates delays, congestion problems as well as minimize the cost of total delay.
Currently, The Central Airspace Management Unit (CAMU) is responsible for the management of air traffic flow and capacity management within South African airspace in collaboration with the South Africa Air Traffic and Navigation Services (ATNS), the sole commercial provider of air traffic, navigation and associated services and responsible for air traffic control in approximately 10% of the world's airspace.
Read the full problem statement
Presentations
Air Traffic Flow Management Rerouting - Alex Somto Alochukwu
Soultions
Air Traffic Flow Management Rerouting
Problem 4: THE UTILITY PRICING DEATH SPIRAL
Industry: Energy (Electricity)
Industrial contact: Professor Barend Erasmus, Global Change and Sustainability Research Institute, University of the Witwatersrand
Problem Statement
Utility providers in large metros price electricity to cover the cost of infrastructure and generation. The electricity network - the wires and poles - have a fixed cost, and consumers pay a charge for consumption to cover the cost of this infrastructure. The exact price is calculated to cover the cost of infrastructure that can cope with loads at peak usage. If the consumer client base shrinks, then the utility needs to increase prices, to cover the fixed costs of using the network infrastructure. This means that a smaller client base have to start paying more, for the same service. In South Africa, most of the metros rely on high-income clients for most of their income. However, this high-income group of clients, are also the most likely, and have the means, to move to alternative source of electricity. This is especially likely if the higher prices are coupled with a perception of substandard service, as was experienced by recent bouts of load-shedding.
Read the full problem statement
Background reading:
Does disruptive competition mean a death spiral for electric utilities?
Why wrong pricing has caused the electricity ‘death spiral’
Is the utility death spiral inevitable for energy companies?
Solutions
The Utility Pricing Death Spiral
Problem 5: AUTOMATED DATA COLLECTION FROM A FOOTBALL VIDEO
Industry: Sports
Industry Representative: Dario Fanucchi, Isazi Consulting
Moderator:
Student Moderator:
Problem Statement:
Data is playing an increasingly important role in sports. Good data assist a scout to choose the most promising candidates for potential recruitment, a coach to focus on the right player combinations and training schedule for his team, a player to better understand and improve his strengths and weaknesses, an advertiser to determine which players on the field generate more crowd and viewer activity, and a betting house to fine tune the odds in advance of a game. Data driven decision making has revolutionized baseball in the USA, and plays a significant role in many other sports. In football, the vital statistics and running distances of players are monitored by devices worn on their bodies, and most games generate several independent streams of video footage from different cameras. The German football team that won the 2014 World Cup used SAP software to analyze their games as well as those of their opponents. The software suggested combinations and moves that would be most likely to succeed against their upcoming opponents and helped monitor training sessions. Collecting and curating quality data from a football match is therefore clearly of immense value for a team and other stakeholders.
Read the full problem statement
Presentations
Automated Data Collection from a Football Video
Soultions
Automated Data Collection from a Football Video
Problem 6: ASSESSMENT OF THE PERFORMANCE OF COMPOSITE LINER: SHOTCRETE AND TSL
Industry: Mining Industry
Representative: Halil Yilmaz, School of Mining Engineering, University of the Witwatersrand, Johannesburg.
Moderator:
Student Moderator:
Problem Statement:
Shotcrete, typically 50 mm to 100 mm thick, has been a traditional surface support applied at the mines for many years. Thin Spray-on Liners (TSLs), on the other hand, have been an alternative to shotcrete with its reduced thickness of about 5 mm to 10 mm. The use and acceptance of TSLs, however, has been problematic simply due to the wrong perception that “a thin liner is a weak liner”. However, numerous physical property tests on both TSLs and shotcrete demonstrated that TSLs, in fact, match and in some cases over perform the strength of shotcrete.
It seems that the acceptance of TSLs would still take a while and shotcrete cannot be singled out in this process of acceptance. It is possible that the worth of TSLs could be shown by TSLs’ influence in the performance enhancement of shotcrete. In this case, a TSL is applied over shotcrete to form a composite liner.
Read the full problem statement
Background reading:
Philani Mpunzi Abstract
Philani Mpunzi-The properties and performance of selected thin spray on liners for rock support
R.Masethe-Abstract Content and Acknowledgement
R.Masethe-Final MSc
Review of membrane support mechanisms, loading mechanisms, desired membrane performance, and appropriate test methods by T.R. Stacey
Presentations
Performance of Composite Liner Shotcrete and Thin Spray-on Liner (TSL)