Leslie Bowtell

Energy characterisation of ultrasonic systems for industrial processes

Obtaining accurate power characteristics of ultrasonic treatment systems is an important step towards their industrial scalability. Calorimetric measurements are most commonly used for quantifying the dissipated ultrasonic power. However, accuracy of these measurements is affected by various heat losses, especially when working at high power densities. In this work, electrical power measurements were conducted at all locations in the piezoelectric ultrasonic system equipped with ½″ and ¾″ probes. A set of heat transfer calculations were developed to estimate the convection heat losses from the reaction solution. Chemical dosimeters represented by the oxidation of potassium iodide, Fricke solution and 4-nitrophenol were used to chemically correlate the effect of various electrical amplitudes and treatment regimes. This allowed estimation of sonochemical-efficiency (SE) and energy conversion (XUS) of the ultrasonic system. Results of this study showed overall conversion efficiencies of 60-70%. This correlated well with the chemical dosimeter yield curves of both organic and inorganic aqueous solutions. All dosimeters showed bubble shielding and coalescence effects at higher ultrasonic power levels, less pronounced for the ½″ probe case. SE and XUS values in the range of 10(-10) mol/J and 10(-3) J/J respectively confirmed that conversion of ultrasonic power to chemical yield declined with amplitude.

Online intravenous pump emulator: as effective as face-to-face simulation for training nursing students

BACKGROUND The expansion of online education for nursing students has created the challenge of finding innovative ways to teach clinical skills. An online intravenous pump emulator (IVPE) modelled on actual IV pumps used in clinical healthcare settings was developed to facilitate online education delivery. OBJECTIVES The objectives of the study were to implement the online IVPE and evaluate student learning outcomes and perceptions of device use. DESIGN A mixed method, quasi-experimental design was used. SETTING The study was conducted in the School of Nursing and Midwifery at a regional university in Queensland, Australia. PARTICIPANTS Participants were 179 first year nursing students enrolled in a medications course, ranging in age from 18 to 44years, of whom 150 were female. METHODS Participants were assigned to one of three groups and trained in the use of IV infusion pumps. Group 1 (n=57) were trained online using the IVPE (ONL); Group 2 (n=73) were trained on-campus using an actual IV pump (ONC); Group 3 (n=49) were trained both on-campus using the actual IV pump and online using the IVPE (ONL+ONC). Competence in using the actual IV pump was assessed for all participants at the conclusion of the training period. RESULTS No significant differences in learning outcomes, measured by assessment scores out of 80 points, were found between the ONL (M=65.5±9.2) and ONC (M=62.0±14.8; p>.05) groups. Significantly better learning outcomes were evident for the ONL+ONC group (M=68.7±4.9) compared to the ONC group (p<.01). CONCLUSIONS This study highlights that the nursing students became more competent in the skill of preparing and administrating IV infusions when face-to-face and online learning were combined.

Investigating the feasibility and the optimal location of pulsed ultrasound in surface water treatment schemes

AbstractThe deterioration of surface water quality due to extreme weather events and increasing human activities has exacerbated the common problems in drinking water production such as filtration fouling and DPBs formation. This in turn has urged for exploring alternative methods for the traditional treatment methods that are able to improve the removal of contaminants with minimal impact on environment and human health. In this study, the application of pulsed and continuous ultrasound for improving the quality of natural water with fresh natural organic matter (NOM) mainly driven from vegetation has been evaluated. The evaluation was performed using cost-effective and quick measurements such as specific UV–vis absorbance, CODMn, alkalinity and conductivity. The changes in the characteristics of NOM induced by ultrasound were used to develop a framework for evaluating ultrasound performance in improving conventional surface water treatment processes and to identify the best fit of ultrasound within the ...

Assessing the application and downstream effects of pulsed mode ultrasound as a pre-treatment for alum coagulation.

The application of pulsed mode ultrasound (PMU) as a pre-treatment for alum coagulation was investigated at various alum dosages and pH levels. The effects of the treatments on turbidity and dissolved organic carbon (DOC) removal and residual Al were evaluated. Response surface methodology (RSM) was utilized to optimize the operating conditions of the applied treatments. The results showed that PMU pre-treatment increased turbidity and DOC removal percentages from maximum of 96.6% and 43% to 98.8% and 52%, respectively. It also helped decrease the minimum residual Al from 0.100 to 0.094 ppm. The multiple response optimization was carried out using the desirability function. A desirability value of >0.97 estimated respective turbidity removal, DOC removal and Al residual of 89.24%, 45.66% and ∼ 0.1 ppm for coagulation (control) and 90.61%, >55% and ∼ 0 for coagulation preceded by PMU. These figures were validated via confirmatory experiments. PMU pre-treatment increased total coliform removal from 80% to >98% and decreased trihalomethane formation potential (THMFP) from 250 to 200 ppb CH3Cl. Additionally, PMU application prior to coagulation improved the settleability of sludge due to the degassing effects. The results of this study confirms that PMU pre-treatment can significantly improve coagulation performance.

Insights into the scalability of magnetostrictive ultrasound technology for water treatment applications

To date, the successful application of large scale ultrasound in water treatment has been a challenge. Magnetostrictive ultrasound technologies for constructing a large-scale water treatment system are proposed in this study. Comprehensive energy evaluation of the proposed system was conducted. The effects of chosen waveform, scalability and reactor design on the performance of the system were explored using chemical dosimetry. Of the fundamental waveforms tested; sine, triangle and square, the highest chemical yield resulted from the square wave source. Scaling up from the 0.5L bench-scale system to the 15 L large-scale unit resulted in a gain of approximately 50% in sonochemical efficiency (SE) for the system. The use of a reactor tank with 45° inclined sides further increased SE of the system by 70%. The ability of the large scale system in removing contaminants from natural water samples was also investigated. The results revealed that the large-scale unit was capable of achieving a maximum removal of microbes and dissolved organic carbon (DOC) of 35% and 5.7% respectively at a power density approximately 3.9 W/L. The results of this study suggest that magnetostrictive ultrasound technology excited with square wave has the potential to be competitive in the water treatment industry.

Tracking ultrasonically structural changes of natural aquatic organic carbon: Chemical fractionation and spectroscopic approaches.

In this study, the structural alteration to DOC for a range of ultrasound treatments was investigated with chemical fractionation and UV-vis spectroscopic measurement. Ultrasound treatments were applied in continuous and pulsed modes at power levels of 48 and 84 W for effective treatment times of 5 and 15 min. Overall results show that the ultrasound treatments tended to degrade the hydrophobic aromatic fraction, while increasing the hydrophilic fraction to a lesser extent. The highest recorded reduction of hydrophobic DOC (17.8%) was achieved with pulse treatment of 84 W for15 min, while the highest increase in the hydrophilic DOC (10.5%) was obtained with continuous treatment at 84 W and 5 min. The optimal ultrasound treatment conditions were found to be pulse mode at high power and short treatment time, causing a minimal increase in the hydrophilic fraction of 1.3% with moderate removal of the hydrophobic fraction of 15.52%. The same treatment conditions, with longer treatment time, resulted in the highest removal of SUVA254 and SUVA280 of 17.09% and 16.93, respectively. These results indicate the potential for ultrasound treatments in DOC structural alteration. The hydrophobic fraction showed strong and significant correlations with UV absorbance at 254 and 280 nm. A254/A204 also exhibited strong and significant correlations with the hydrophobic/hydrophilic ratio. The other UV ratios (A250/A365 (E2/E3) and A254/A436) had weak and insignificant correlations with the hydrophobic/hydrophilic ratio. This confirms the applicability of UV indices as a suitable surrogate method for estimating the hydrophobic/hydrophilic structure.

Improving clinical practice outcomes for nurses with an interactive emulator

Historically, nursing students have shown great difficulty in mastering equipment during clinical practice sessions. A typical example is the Intravenous (IV) pump infusion driver. Traditional training methods have relied upon on-campus practical group training sessions. Recent work in this area has demonstrated that Remote Access Laboratories (RAL) can be employed to enhance nursing education by providing access to an IV pump driver learning activity. The prototype closely mimicked the interface and audible feedback of a commonly used IV pump driver; and controlled a peristaltic pump to deliver the prescribed rates and volumes. This project takes this approach a step further and investigates a completely emulated interface in the same RAL environment. The aim is to target five problem areas that were previously identified. These include the screen navigation and data entry of the IV pump driver; and the correct calculation and entry of medication volumes and rates from a standard fluid chart. To address these issues the learning environment was modified to include a guided learning mode, integrated scaffolding resources and facility of self-assessment. This paper discusses implementation and results of a pilot study to evaluate the effectiveness of this approach. Initial results are promising and show a distinct improvement in the practical capability of those students who participated in the trial.