A solar disinfection water treatment system for remote communities

Abstract not availablePeter Kalt, Cristian Birzer, Harrison Evans, Anthony Liew, Mark Padovan, Michael Watchma

Effect of total solids content on anaerobic digestion of poultry litter with biochar

Methane production via anaerobic digestion of poultry litter provides a pathway for energy production from an abundant waste product. Recent studies have shown the use of biochar (pyrolysed biomass) can decrease methane production lag times and increase peak daily yields from ammonia-stressed low-solids anaerobic digesters. Due to the variety of feedstocks and digester configurations used, research to date has not yet determined the effect of biochar addition as a function of the digester total solids content. This study shows the addition of biochar reduces the lag time by a greater percentage in the digesters with a higher total solids content. There was a 17%, 27% and 41% reduction lag time due to biochar addition at total solids contents of 5%, 10% and 20%, respectively. The peak daily methane yield increased by 136% at 10% total solids. There was no significant increase in the peak yield at 5% total solids, while there was a 46% increase at 20% total solids. Real-time PCR analysis confirms the Methanosaetaceae family, which is a key methanogen due to its ability to facilitate direct interspecies electron transfer while attached to biochar, preferentially attaches to biochar. Furthermore, this research shows the attachment of the Methanosaetaceae family, does not decrease with increasing total solids content. A potential negative effect of biochar addition, a reduced volumetric efficiency, can be negated by using a shorter retention time. This new understanding will help to improve predictions of the impact of biochar addition for new digester designs operating in semi-solids and high-solids conditions.Mathu Indren, Cristian H.Birzer, Stephen P.Kidd, Paul R.Medwel

Effects of biochar parent material and microbial pre-loading in biochar-amended high-solids anaerobic digestion

This study characterises the effect of biochar (pyrolysed biomass) produced from wood pellets, wheat straw and sheep manure on high-solids anaerobic digestion (HSAD) of poultry litter. Also, pre-loading biochar with microorganisms before addition to HSADs was investigated. The addition of wood pellet biochar provides a 32% increase to the methane yield compared with control digesters. The addition of biochar produced from either wheat straw or sheep manure has detrimental effects on digester performance compared with controls. The addition of wood pellet biochar pre-loaded by placing it in a high-solids digester for 90 days provides a 69% increase in the total methane yield, 44% increase in the peak daily methane yield and a 33% reduction in the lag time compared with controls. This study highlighted a need for careful selection of parent material for biochar production and, for the first time, the opportunities to re-use wood pellet biochar for further improvements.Mathu Indren, Cristian H. Birzer, Stephen P. Kidd, Tony Hall, Paul R. Medwel

An analysis of combustion from a top-lit up-draft (TLUD) cookstove

It is estimated that three billion people worldwide cook with traditional stoves. These stoves generaly consist of three stones and an open fire, and produce harmful emissions that are known to cause fatal illnesses. Traditional stoves claim the lives of 1.6 million people every year and cause the death of more children under the age of five than any other single cause. In addition, widespread land degradation and deforestation have resulted from inefficient fuel consumption of traditional stoves. This paper presents some results from an extensive investigation into design and experimental evalation of top-lit up-draft (TLUD) microgasifier cookstoves aimed at addressing problems associated with traditional cooking approaches. Results indicate that geometric variations of the stove and fuel size influence burn rates and emissions production, and must therefore be considered for any design and implementation.Cristian Birzer, Paul Medwell, Josh Wilkey, Tomas West, Matthew Higgins, Gregory MacFarlane and Matthew Rea

The Structure and Delivery of Police Use of Force Training: A German Case Study

The current study aims to investigate the current structure and delivery of police recruit training. Using a case study approach, we systematically observed a semester of police training that consisted of 30 h with a specific focus on police use of force training. Field notes and time-on-task data was analysed using an inductive approach. The results revealed, first, a lack of constructive alignment of the training modules and learning tasks within the training settings. Second, an adherence to traditional linear approaches to training resulting in high amounts of augmented instruction and feedback and a one-size-fits all approach to technical and tactical behaviour. Third, a non-efficient use of available training time with low amounts of engagement in representatively designed tasks that stimulated problem-solving processes. Based on these results we suggest that there is a need: (a) for police trainers and curriculum designers to align the objectives, practice structure and delivery of police training with the needs of police officers in the field (e.g. conflict resolution); (b) for police trainers to employ more learner-centred pedagogical approaches that account for individual action capabilities and resources, and allow for high amounts of training time with representatively designed training tasks; and (c) for senior managers of overall police training decision-makers to provide the necessary trainer education, in order to furnish trainers with the knowledge and tools to appropriately plan, deliver and reflect upon their practice in keeping with concept of constructive alignment

Investigating the flow effects of slots and perforations on a flat blade

The following study investigates the flow effects caused by slots and perforations on a flat blade for use in a simple, undershot, water-wheel to better understand the flow mechanics of these turbines. This study has a primary aim of increasing the power generated by these blades without significantly increasing manufacturing costs. Experimental tests were conducted in a wind tunnel with 2.4% blockage ratio. These tests aimed to measure the power coefficient of the blade over a range of flow velocities and angles of attack. Reynolds Number matching was used to ensure that the use of a wind tunnel for a water-based design was adequate. Initial tests were undertaken on four designs with similar porosity ratios. After the initial results were found, these designs evolved to find an optimal solution. The results show that, under the test conditions, the square slotted design with porosity, Φ, of 0.1 was optimal. It provided a slight increase in overall power coefficient at high angle of attack while using 10% less manufacturing material. The final design also improved downstream flow effects, causing a more rapid decay in the wake velocity. This increases the power generation of blades further downstream when used in a turbine configuration. Collectively, these results provide an insight into the flow effects of perforated and slotted flat blades in a controlled experimental environment, which will be used in the future to improve the design of the simple water-wheel.M. L. Toole, R. M. Kelso, and C. Birze

Investigation into the response force of a dielectric barrier discharge plasma actuator with varying electrode angle using particle image velocimetry

Dielectric barrier discharge (DBD) plasma actuators induce an ionic wind that imparts momentum to the surrounding air, resulting in a net response force being produced. The upstream ionic wind is drawn inwards from above the actuator before being directed downstream parallel to the dielectric plate. Varying the angle between the electrodes in a DBD plasma actuator changes the magnitude and direction of the resultant response force. Increasing the angle results in a higher achieved response force. It is hypothesised that changing the angle between the electrodes alters the direction of the upstream and downstream components of the ionic wind. Particle image velocimetry (PIV) has been used to determine the flow directions of the ionic wind for various electrode angles in a DBD actuator. The results indicate that changing the angle between the electrodes, re-aligns the ionic wind components resulting in changes to the response force as predicted.A Greig, C Birzer and M Arjomandihttp://www.acldfmc.org

Atmospheric plasma thruster: Theory and concept

Dielectric barrier discharge plasma actuators generate a net response force that exhibits potential for thrust applications such as propulsive systems. In this work, an angled actuator in which the exposed and encased electrodes are not parallel has been investigated using direct force measurements and particle image velocimetry. It was shown that the induced force was nonlinearly increased by increasing the angle between the electrodes. In addition, the direction of the upstream component of the ionic wind was changed by varying the electrode angle. Modifying the angle between the electrodes changes the electric field strength in the vicinity of the plasma actuator, thereby changing the response force produced. Analytical calculations were used to compare expected results with results obtained experimentally. Then, using the results obtained experimentally, a plasma thruster was designed as proof of concept for dielectric barrier discharge plasma actuators as propulsive devices.A. Greig, C. H. Birzer, and M. Arjomand