An investigation into the behaviour of concrete containing seawater-neutralised bauxite refinery residues in silage effluent

The farm production of silage as a winter-feed supplement is widespread. However, the bins in which silage is produced are subject to acidic and microbial attacks. Both these types of attack can lead to a weakening and failure of the concretes, especially on the outer lip of the open side of the silage pit. Consequently, the development of an acid-resistant concrete that can extend the life span of silage bins on farms could lead to considerable cost savings for farmers and, hence, can improve farm productivity. This paper reports on test results of an investigation into the behaviour of concrete containing seawater-neutralised bauxite refinery residues (Bauxsol™) exposed to sulphuric acid environments in the laboratory and to silage effluents. The concrete manufactured had a fixed water–cement ratio of 0.55 and natural sand was replaced with the Bauxsol™ at 0%, 5%, 10%, 15% and 20% by cement mass. Results indicated that the use of Bauxsol™ as a sand replacement material improved the behaviour of concrete both in sulphuric acid in the laboratory as well as in the silage effluent. Consequently, it is concluded that the Bauxsol™ can be used to replace 10% of natural sand to produce concrete that is resistant to silage effluents, providing an extended service life over conventional concretes used in silage pits.

Dual Sequence Simulated Annealing with Round-Robin Approach for University Course Timetabling

The university course timetabling problem involves assigning a given number of events into a limited number of timeslots and rooms under a given set of constraints; the objective is to satisfy the hard constraints (essential requirements) and minimize the violation of soft constraints (desirable requirements). In this study we employed a Dual-sequence Simulated Annealing (DSA) algorithm as an improvement algorithm. The Round Robin (RR) algorithm is used to control the selection of neighbourhood structures within DSA. The performance of our approach is tested over eleven benchmark datasets. Experimental results show that our approach is able to generate competitive results when compared with other state-of-the-art techniques.

Abatement and Allocation in the Pilot Phase of the EU ETS

We use historical industrial emissions data to assess the level of abatement and over-allocation that took place across European countries during the pilot phase (2005–2007) of the European Union Emission Trading Scheme. Using a dynamic panel data model, we estimate the counter factual (business-as-usual) emissions scenario for EU member states. Comparing this baseline to allocated and verified emissions, we find that both over-allocation and abatement occurred, along with under-allocation and emissions inflation. Over the three trading years of the pilot phase we find over-allocation of approximately 280 million EUAs and total abatement of 247 Mt CO2. However, we calculate that emissions inflation of approximately 73 Mt CO2 also occurred, possibly due to uncertainty about future policy design features.