Simulation and evaluation of HERIC and H5 transformerless inverter topologies

Most of the inverters have an isolation transformer which prevents or limits fault current between AC and DC circuits under most fault conditions. If the transformer is excluded from the system, it would increase the PV system efficiency and decrease the size of its installations, which will lead to a lower cost for the whole investment. Thus, elimination of the transformer has to be considered carefully because a galvanic connection appears between the PV arrays and the ground in the absence of an isolation transformer. The galvanic connection causes the stray capacitance between the PV arrays structure and the ground to produce a leakage current. In this paper, a review of full bridge topology with bipolar and unipolar scheme and half bridge topology carried out in regard leakage current.in addition, HERIC and H5 topologies are simulated and leakage current in these topologies are evaluated.

Neoliberal policy agendas and the problem of inequality in higher education: the Ethiopian case

Under the influence of the external policy pressure of donors such as the World Bank, higher education in Ethiopia has witnessed a series of institutional and system-wide reforms. This article reviews selected policy documents to show key neo-liberal policy agendas endorsed in the reforms and explicate how they have affected social equity in the subsystem. The analysis shows that higher education reforms in Ethiopia, primarily framed by concerns of economic efficiency, have constrained social equity in two important ways. First, at a discursive level, the problem of inequality is represented as a lack of access and a disadvantage in the human capital formation of the nation. Second, the drive for greater efficiency and reduced costs in the educational provision embedded in the reforms is inconsistent with the need for the financial and political commitments required to benefit marginalised members of the society through relevant equity instruments. If the equity policy provisions should be instrumental in ensuring participation, retention and successful completion, and thereby supporting the social mobility of disadvantaged groups, they need to draw on a broad social justice perspective.

Complex coacervation with whey protein isolate and gum arabic for the microencapsulation of omega-3 rich tuna oil.

Tuna oil rich in omega-3 fatty acids was microencapsulated in whey protein isolate (WPI)-gum arabic (GA) complex coacervates, and subsequently dried using spray and freeze drying to produce solid microcapsules. The oxidative stability, oil microencapsulation efficiency, surface oil and morphology of these solid microcapsules were determined. The complex coacervation process between WPI and GA was optimised in terms of pH, and WPI-to-GA ratio, using zeta potential, turbidity, and morphology of the microcapsules. The optimum pH and WPI-to-GA ratio for complex coacervation was found to be 3.75 and 3 : 1, respectively. The spray dried solid microcapsules had better stability against oxidation, higher oil microencapsulation efficiency and lower surface oil content compared to the freeze dried microcapsules. The surface of the spray dried microcapsules did not show microscopic pores while the surface of the freeze dried microcapsules was more porous. This study suggests that solid microcapsules of omega-3 rich oils can be produced using WPI-GA complex coacervates followed by spray drying and these microcapsules can be quite stable against oxidation. These microcapsules can have many potential applications in the functional food and nutraceuticals industry.

Why has the safety and quality movement been slow to improve care?

Buist and Middleton lament that the safety and quality 'agenda' has failed to fundamentally alter the safety of healthcare systems, in part because of the disengagement of doctors from their responsibilities for patient safety . While there have been discernable improvements in the efficiency and effectiveness of care in some settings, patients still experience unacceptable harm and often struggle to have their voices heard; processes are not as efficient as they could be; and costs continue to rise at alarming rates while quality issues remain . Perhaps of most concern, recent public reports into health system failures continue to document a widespread lack of attentiveness to patient concerns, a culture of denial and widespread lack of professionalism . Alarmingly, clinician discontentment, cynicism and burn-out are reflected in antagonistic language by clinicians about the healthcare system and their patients. Taken together with the many dissatisfied and now more vocal patient groups, all point to an unprecedented crisis of faith in our healthcare systems which has been getting worse over past decade . This personal perspective aims to address the fundamental tensions that are keeping much of healthcare reform efforts from successfully transforming the culture and outcomes except at the margins.

Using response action with Intelligent Intrusion detection and prevention System against web application malware

Findings: After evaluating the new system, a better result was generated in line with detection efficiency and the false alarm rate. This demonstrates the value of direct response action in an intrusion detection system.

Supplementing cold plasma with heat enables doping and nano-structuring of metal oxides

Nitrogen doped SnO2 polycrystalline nanostructures were produced from commercial SnO powders in a new system that combines a low-temperature plasma with heating. The method has the potential to improve the initial efficiency and the cycling performance of SnO2 anodes in Li-ion batteries. With this system, the temperature of the SnO to SnO2 conversion was lowered from 430 to 320 °C, up to 5 at% of doped nitrogen was detected and a nano-scale polycrystalline structure was observed in the product. Combining heat and low-pressure plasma is a promising approach for the production and treatment of enhanced energy storage materials.

Computational chemistry for graphene-based energy applications: progress and challenges.

Research in graphene-based energy materials is a rapidly growing area. Many graphene-based energy applications involve interfacial processes. To enable advances in the design of these energy materials, such that their operation, economy, efficiency and durability is at least comparable with fossil-fuel based alternatives, connections between the molecular-scale structure and function of these interfaces are needed. While it is experimentally challenging to resolve this interfacial structure, molecular simulation and computational chemistry can help bridge these gaps. In this Review, we summarise recent progress in the application of computational chemistry to graphene-based materials for fuel cells, batteries, photovoltaics and supercapacitors. We also outline both the bright prospects and emerging challenges these techniques face for application to graphene-based energy materials in future.

Reliable multicast with pipelined network coding using opportunistic feeding and routing

Multicast is an important mechanism in modern wireless networks and has attracted significant efforts to improve its performance with different metrics including throughput, delay, energy efficiency, etc. Traditionally, an ideal loss-free channel model is widely used to facilitate routing protocol design. However, the quality of wireless links is affected or even jeopardized resulting in transmission failures by many factors like collisions, fading or the noise of environment. In this paper, we propose a reliable multicast protocol, called CodePipe, with energy-efficiency, high throughput and fairness in lossy wireless networks. Building upon opportunistic routing and random linear network coding, CodePipe can not only eliminate coordination between nodes, but also improve the multicast throughput significantly by exploiting both intra-batch and inter-batch coding opportunities. In particular, four key techniques, namely, LP-based opportunistic routing structure, opportunistic feeding, fast batch moving and inter-batch coding, are proposed to offer significant improvement in throughput, energy-efficiency and fairness.Moreover, we design an efficient online extension of CodePipe such that it can work in a dynamic network where nodes join and leave the network as time progresses. We evaluate CodePipe on ns2 simulator by comparing with other two state-of-art multicast protocols,MORE and Pacifier. Simulation results show that CodePipe significantly outperforms both of them.

Microstructure modeling and prediction of the mechanical properties of advanced high strength steels

Dual phase (DP) steels were modeled using 2D and 3D representative volume elements (RVE). Both the 2D and 3D models were generated using the Monte-Carlo-Potts method to represent the realistic microstructural details. In the 2D model, a balance between computational efficiency and required accuracy in truly representing heterogeneous microstructure was achieved. In the 3D model, a stochastic template was used to generate a model with high spatial fidelity. The 2D model proved to be efficient for characterization of the mechanical properties of a DP steel where the effect of phase distribution, morphology and strain partitioning was studied. In contrast, the current 3D modeling technique was inefficient and impractical due to significant time cost. It is shown that the newly proposed 2D model generation technique is versatile and sufficiently accurate to capture mechanical properties of steels with heterogeneous microstructure.

Failures in communication through documents and documentation across the perioperative pathway.

AIMS AND OBJECTIVES: To explore how communication failures occur in documents and documentations across the perioperative pathway in nurses' interactions with other nurses, surgeons and anaesthetists. BACKGROUND: Documents and documentation are used to communicate vital patient and procedural information among nurses, and in nurses' interactions with surgeons and anaesthetists, across the perioperative pathway. Previous research indicates that communication failure regularly occurs in the perioperative setting. DESIGN: A qualitative study was undertaken. METHODS: The study was conducted over three hospitals in Melbourne, Australia. One hundred and twenty-five healthcare professionals from the disciplines of surgery, anaesthesia and nursing participated in the study. Data collection commenced in January 2010 and concluded in October 2010. Data were generated through 350 hours of observation, two focus groups and 20 semi-structured interviews. A detailed thematic analysis was undertaken. RESULTS: Communication failure occurred owing to a reliance on documents and documentation to transfer information at patient transition points, poor quality documents and documentation, and problematic access to information. Institutional ruling practices of professional practice, efficiency and productivity, and fiscal constraint dominated the coordination of nurses', surgeons' and anaesthetists' communication through documents and documentation. These governing practices configured communication to be incongruous with reliably meeting safety and quality objectives. CONCLUSIONS: Communication failure occurred because important information was sometimes buried in documents, insufficient, inaccurate, out-of-date or not verbally reinforced. Furthermore, busy nurses were not always able to access information they required in a timely manner. Patient safety was affected, which led to delays in treatment and at times inadequate care. RELEVANCE TO CLINICAL PRACTICE: Organisational support needs to be provided to nurses, surgeons and anaesthetists so they have sufficient time to complete, locate, and read documents and documentation. Infrastructure supporting communication technologies should be implemented to enable the rapid retrieval, entry, and dispersion of information.