Computer Simulation of PMSM Motor with Five Phase Inverter Control using Signal Processing Techniques

The signal processing techniques and computer simulation play an important role in the fault diagnosis and tolerance of all types of machines in the first step of design. Permanent magnet synchronous motor (PMSM) and five phase inverter with sine wave pulse width modulation (SPWM) strategy is developed. The PMSM speed is controlled by vector control. In this work, a fault tolerant control (FTC) system in the PMSM using wavelet switching is introduced. The feature extraction property of wavelet analysis used the error as obtained by the wavelet de-noised signal as input to the mechanism unit to decide the healthy system. The diagnosis algorithm, which depends on both wavelet and vector control to generate PWM as current based manage any parameter variation. An open-end phase PMSM has a larger range of speed regulation than normal PMSM. Simulation results confirm the validity and effectiveness of the switching strategy

Quasi-Zero Dimensional Halide Perovskite Derivates: Synthesis, Status, and Opportunity

In recent decades, many technological advances have been enabled by nanoscale phenomena, giving rise to the field of nanotechnology. In particular, unique optical and electronic phenomena occur on length scales less than 10 nanometres, which enable novel applications. Halide perovskites have been the focus of intense research on their optoelectronic properties and have demonstrated impressive performance in photovoltaic devices and later in other optoelectronic technologies, such as lasers and light-emitting diodes. The most studied crystalline form is the three-dimensional one, but, recently, the exploration of the low-dimensional derivatives has enabled new sub-classes of halide perovskite materials to emerge with distinct properties. In these materials, low-dimensional metal halide structures responsible for the electronic properties are separated and partially insulated from one another by the (typically organic) cations. Confinement occurs on a crystal lattice level, enabling bulk or thin-film materials that retain a degree of low-dimensional character. In particular, quasi-zero dimensional perovskite derivatives are proving to have distinct electronic, absorption, and photoluminescence properties. They are being explored for various technologies beyond photovoltaics (e.g. thermoelectrics, lasing, photodetectors, memristors, capacitors, LEDs). This review brings together the recent literature on these zero-dimensional materials in an interdisciplinary way that can spur applications for these compounds. The synthesis methods, the electrical, optical, and chemical properties, the advances in applications, and the challenges that need to be overcome as candidates for future electronic devices have been covered

Climate Change and Decision Theory

Many people are worried about the harmful effects of climate change but nevertheless enjoy some activities that contribute to the emission of greenhouse gas (driving, flying, eating meat, etc.), the main cause of climate change. How should such people make choices between engaging in and refraining from enjoyable greenhouse-gas-emitting activities? In this chapter we look at the answer provided by decision theory. Some scholars think that the right answer is given by interactive decision theory, or game theory; and moreover think that since private climate decisions are instances of the prisoner’s dilemma, one rationally should engage in these activities provided that one enjoys them. Others think that the right answer is given by expected utility theory, the best-known version of individual decision theory under risk and uncertainty. In this chapter we review these different answers, with a special focus on the latter answer and the debate it has generated

On the issue of predictors of complications of surgical treatment of patients with spinal cord injury in the lower thoracic and lumbar spine

Objective. To determine the predictors of complications of surgical treatment of patients with spinal cord injury (SCI) in the lower thoracic and lumbar spine using various options for performing decompression and stabilization surgeries. Material and Methods. A total of 240 patients with spinal cord injury in the lower thoracic and lumbar spine were operated on in 2010–2021. All patients were divided into 3 groups depending on the tactical option of surgical treatment performed. In Group 1, patients (n = 129) underwent two-stage surgical intervention through combined approach: the first stage included transpedicular fixation (TPF) supplemented with posterior decompression options and the second stage – fusion through anterior approach, in Group 2 (n = 36) – TPF and decompression through posterior approach, and in Group 3 (n = 75) – one-stage surgical intervention including TPF, decompression and fusion through extended posterior approach. An analysis of surgical complications was carried out, and factors that increase the likelihood of their development were identified. Comparison of groups according to quantitative indicators was carried out using single-factor analysis of variance (with normal distribution), and Kruskal-Wallis test (with distribution other than normal). Comparison of percentages in the analysis of multifield contingency tables was performed using Pearson’s χ2 test. Results. A total of 130 cases of postoperative complications were identified that corresponded to the grade 2 or 3 of the Clavien – Dindo classification, including respiratory, infectious processes in the surgical site, iatrogenic neurological complications, intraoperative damage to the dura mater, and instability of metal fixation. In two-stage surgery through combined approaches, the most common were respiratory complications (17.1 %), intraoperative damage to the dura mater (9.3 %) and surgical site infection (7.0 %). Predictors of these complications included the severity of preoperative neurological deficit of ASIA grade A or B, the patient’s preoperative condition corresponding to the average risk of death according to the modified SOFA score, and the performance of extended laminectomy. In isolated TPF with reposition and stabilization without fusion, the most common complication was instability of metal fixation in the long-term period (47.1 %), the predictors of which were incomplete reposition of the fractured vertebral body and performing two-segment TPF. In one-stage decompression and stabilization interventions with TPF and fusion through the extended posterior approach, the most common complications were intraoperative damage to the dura mater (26.7 %), respiratory complications (18.7 %), infectious processes in the surgical site (10.7 %), iatrogenic neurological complications (12.0 %), and instability of metal fixation (16.1 %). Predictors of these complications were the severity of the patient’s condition before surgery, corresponding to the average risk of death according to the modified SOFA score, neurological deficit of type D or rapidly regressing neurological deficit of type C, A or B according to ASIA scale, and bisegmental fusion when the injury was located at the lumbar level. Conclusion. Analysis of the causes of complication development contributes to their prevention, and can also form the basis for algorithms to choose tactics and technology for performing decompression and stabilization operations

Landfill Futures: : National Guideline Document

This report looks at the past and present roles of landfills in Australian waste management and considers the requirements for a sustainable future. The research used a test case to apply an integrated resource planning model to waste. The results suggest that disposal to landfill may be an expensive and less preferred option compared to others, in many cases, but still have a role to play in specific contexts where the costs of other options are higher