Vertical axis wind turbine generator case study : costs and losses associated with variable torque and variable speed strategies

This case study investigates the generator of a large offshore Vertical Axis Wind Turbine (VAWT). In particular this case study focuses on the effect of the inherent cyclic torque loading of the VAWT on the generator in terms of the costs and losses experienced. A spectrum of torque control strategies were created based on the ratio q of the allowed electrical torque variation to the mechanical torque variation. Equations relating the copper and iron losses of the generator to this q factor were established and investigated for a test turbine. In addition the relationship between the allowed variation in electrical torque and the cost of the active materials of the generator was explored

Comparison of dimethyl sulfoxide treated highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) electrodes for use in indium tin oxide-free organic electronic photovoltaic devices

Indium tin oxide (ITO)-free organic photovoltaic (OPV) devices were fabricated using highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as the transparent conductive electrode (TCE). The intrinsic conductivity of the PEDOT:PSS films was improved by two different dimethyl sulfoxide (DMSO) treatments – (i) DMSO was added directly to the PEDOT:PSS solution (PEDOT:PSSADD) and (ii) a pre-formed PEDOT:PSS film was immersed in DMSO (PEDOT:PSSIMM). X-ray photoelectron spectroscopy (XPS) and conductive atomic force microscopy (CAFM) studies showed a large amount of PSS was removed from the PEDOT:PSSIMM electrode surface. OPV devices based on a poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bulk hetrojunction showed that the PEDOT:PSSIMM electrode out-performed the PEDOT:PSSADD electrode, primarily due to an increase in short circuit current density from 6.62 mA cm−2 to 7.15 mA cm−2. The results highlight the importance of optimising the treatment of PEDOT:PSS electrodes and demonstrate their potential as an alternative TCE for rapid processing and low-cost OPV and other organic electronic devices

Imaging findings in a patient with eosinophilic pneumonia (Lvffler's syndrome)

Löffler’s syndrome was initially described as a disorder characterised by transient pulmonary infiltrates accompanied by peripheral blood eosinophilia in asymptomatic or mildly ill patients. Abnormal chest radiographic findings are said to occur in 95% of patients but there are no descriptions of CT findings. There are many causes of this syndrome, but in developing countries the most common presentation remains secondary to the migratory larvae of common intestinal helminths. We present the clinical and radiological features of a boy with clearly defined Löffler's syndrome due to larval migration

Resuscitation in major burns: The problem of fluid creep

We have noticed an alarming tendency for burn patients to be over-resuscitated, and we believe that protocols should be reviewed in light of our own and international experience. We recently managed an 8-year-old boy with 52% fullthickness burns, who developed abdominal and limb compartment syndromes during the period of resuscitation. The fluid volumes infused above those calculated were 1.6 and 4.7 litres on days 1 and 2 respectively to maintain haemodynamic stability and urine output above 2 ml/kg/h. Within 48 hours of the injury, he developed poor peripheral perfusion and a distended abdomen; the intravesical pressure was 32 mmHg and the abdominal perfusion pressure 23 mmHg. Abdominal decompression and three limb fasciotomies were performed, but small-bowel and lower limb muscle necrosis had developed. The patient deteriorated rapidly despite inotropic support and died

Medics in southern Queensland: Effects of sowing method, weed control and phosphorus application on plant population and biomass

Declining sown pasture productivity as a result of a tie-up in plant available soil nitrogen is an ongoing constraint to grazing production across the brigalow bioregion of central and southern Queensland. Research suggests that legume establishment offers the most cost effective long-term remediation strategy for improving pasture quality and yield. Within southern Queensland, medics (Medicago spp.) can provide valuable winter contributions to dietary protein and soil nitrogen, however establishment and yields are frequently poor and soil phosphorus often limiting. An experiment was established across two soil types (brigalow clay and poplar box red loam) 70 km north of Goondiwindi, Queensland to investigate the effects of sowing method, weed control and phosphorus fertiliser application on the establishment and yield of a mix of three medic cultivars (Medicago truncatula cv. Jester & cv .Caliph and Medicago orbicularis cv. Bindaroo Gold). On both soil types, plant population and biomass were significantly improved via direct drilling of seed as compared to broadcasting. On the loam, drilling increased average populations by between 519 and 1,900% above those recorded in broadcast treatments and improved biomass by between 144 and 315%. On the clay soil, drilling increased populations by between 339 and 983% above those measured in broadcast treatments. Clay soil drilling showed biomass improvements of between 124 and 1,368%. No significant biomass or legume population treatment effects were observed on the clay soil. No significant treatment effects were observed for yield on the loam soil. This study implies that medic establishment, plant populations and biomass can be greatly improved through the application of seed drilling

Determining the extent of declining pasture productivity with nitrogen fertiliser

Declining productivity of sown pastures due to a reduction in plant available soil nitrogen has typically reduced grass and beef production by 50% since initial land development within the Brigalow bioregion of southern and central Queensland. As this decline continues, it’s estimated it will cost the northern beef industry more than $17 billion over the next 30 years. To assist landholders determine the extent of declining pasture productivity on their own properties, and assess the magnitude of response if more nitrogen is made available, nitrogen fertiliser was applied to approximately 70 replicated and non-replicated sites across southern and central Queensland between 2012 and 2014. Nitrogen (N) fertiliser as Green Urea NV® (Incitec Fertilisers) was broadcast onto existing grass-pastures in the lead up to a forecast rainfall event in summer. A range of rates were applied, from 25 – 200 kg N/ha, and dry matter yields and protein levels were measured. At all sites the grass pasture responded to the added nitrogen, with the magnitude of response dependant on the amount of nitrogen applied. As the production from sown pastures continues to decline, options that improve nitrogen supply and address this decline will be required to improve beef production across the northern region

Azamacrocycles and tertiary amines can be used to form size tuneable hollow structures or monodisperse oxide nanoparticles depending on the 'M' source.

We show that the azamacrocycle 'cyclam' (1,4,8,11-tetraazacyclodecane) in conjunction with a silicon catecholate ion generates novel hollow tetragonal tube-like crystalline materials [(C6H4O2)3Si][C10H26N4]·H2O, whose dimensions can be tuned according to the pH of the reaction medium. The synthesis approach was successful for both silicon and germanium and we hypothesise that a range of other catecholate precursors of elements such as iron could be used to generate a large array of inorganic materials with interesting morphologies. The synthesis approach can be extended to tertiary diamines with functional group spacing playing an important role in the efficacy of complexation. Of the molecules explored to date, a C2 spacing (N,N,N',N'-Tetramethylethylenediamine (4MEDAE)), leads to the most efficient structure control with hollow hexagonal tube-like structures being formed. In addition, we show that azamacrocycles, in the presence of unbuffered tetramethoxysilane (TMOS) solutions can be used to manipulate silica formation and provide a fast (ca. 10 minutes) synthesis route to particles whose diameter can be tuned from ca. 20nm to several hundreds of nm under reaction conditions (no extremes of pH) that make the sols suitable for direct use in biotechnological applications

The intensive care medicine clinical research agenda in paediatrics

BACKGROUND: Intensive Care Medicine set us the task of outlining a global clinical research agenda for paediatric intensive care (PIC). In line with the clinical focus of this journal, we have limited this to research that may directly influence patient care. METHODS: Clinician researchers from PIC research networks of varying degrees of formality from around the world were invited to answer two main questions: (1) What have been the major recent advances in paediatric critical care research? (2) What are the top 10 studies for the next 10 years? RESULTS: (1) Inclusive databases are well established in many countries. These registries allow detailed observational studies and feasibility testing of clinical trial protocols. Recent trials are larger and more valuable, and (2) most common interventions in PIC are not evidenced-based. Clinical studies for the next 10 years should address this deficit, including: ventilation techniques and interfaces; fluid, transfusion and feeding strategies; optimal targets for vital signs; multiple organ failure definitions, mechanisms and treatments; trauma, prevention and treatment; improving safety; comfort of the patient and their family; appropriate care in the face of medical complexity; defining post-PICU outcomes; and improving knowledge generation and adoption, with novel trial design and implementation strategies. The group specifically highlighted the need for research in resource-limited environments wherein mortality remains often tenfold higher than in well-resourced settings. CONCLUSIONS: Paediatric intensive care research has never been healthier, but many gaps in knowledge remain. We need to close these urgently. The impact of new knowledge will be greatest in resource-limited environments

Characteristics course and outcomes of children admitted to a paediatric intensive care unit after cardiac arrest

Background. Cardiac arrest is a potentially devastating event, associated with death or severe neurological complications in survivors. There is little evidence on paediatric cardiac arrest prevalence, characteristics and outcomes in South Africa (SA). Objective. To describe the characteristics, course and outcomes of children admitted to an SA paediatric intensive care unit (PICU) following cardiac arrest. Methods. Retrospective descriptive study of routinely collected data (January 2010 - December 2011). Results. Of 2 501 PICU admissions, 110 (4.4%) had preceding cardiac arrest. The median (interquartile range (IQR)) age of children was 7.2 (2.5 - 21.6) months. In-hospital arrests accounted for 80.6% of the events. The most common primary diagnostic categories were respiratory (29.1%), cardiovascular (21.4%) and gastrointestinal (21.4%). Twenty-four patients (23.3%) arrested during endotracheal intubation. Cardiopulmonary resuscitation (CPR) was applied for a median (IQR) of 10 (5 - 20) minutes. Duration of CPR for non-survivors and survivors was 17.5 (10 - 30) v. 10 (5 - 15) minutes (p=0.006). PICU mortality was 38.8%, with half of the deaths occurring within 24 hours of admission. The standardised mortality ratio was 0.7. The median (IQR) length of stay in the PICU and hospital was 3 (1 - 8) and 27 (9 -52) days, respectively. No independent predictors of mortality were identified. Thirty-nine surviving patients (76.5%) had normal neurological function or mild disability at follow-up after hospital discharge. Six (11.8%) survived with severe disability. Conclusion. Mortality was lower than predicted in children admitted to the PICU following cardiac arrest. The majority of survivors had good neurological outcomes

Determining the extent of declining pasture productivity with nitrogen fertiliser

Declining productivity of sown pastures due to a reduction in plant available soil nitrogen has typically reduced grass and beef production by 50% since initial land development within the Brigalow bioregion of southern and central Queensland. As this decline continues, it’s estimated it will cost the northern beef industry more than $17 billion over the next 30 years. To assist landholders determine the extent of declining pasture productivity on their own properties, and assess the magnitude of response if more nitrogen is made available, nitrogen fertiliser was applied to approximately 70 replicated and non-replicated sites across southern and central Queensland between 2012 and 2014. Nitrogen (N) fertiliser as Green Urea NV® (Incitec Fertilisers) was broadcast onto existing grass-pastures in the lead up to a forecast rainfall event in summer. A range of rates were applied, from 25 – 200 kg N/ha, and dry matter yields and protein levels were measured. At all sites the grass pasture responded to the added nitrogen, with the magnitude of response dependant on the amount of nitrogen applied. As the production from sown pastures continues to decline, options that improve nitrogen supply and address this decline will be required to improve beef production across the northern region