Simulation of SVPWM Based Multivariable Control Method for a DFIG Wind Energy System

This paper deals with a variable speed device toproduce electrical energy on a power network based on adoubly-fed induction machine used in generating mode(DFIG) in wind energy system by using SVPWM powertransfer matrix. This paper presents a modeling and controlapproach which uses instantaneous real and reactive powerinstead of dq components of currents in a vector controlscheme. The main features of the proposed model comparedto conventional models in the dq frame of reference arerobustness and simplicity of realization. The sequential loopclosing technique is adopted to design a multivariable controlsystem including six compensators for a DFIG wind energysystem to capture the maximum wind power and to inject therequired reactive power to the generator. In this paperSVPWM method is used for better controlling of converters.It also provides fault ride through method to protect theconverter during a fault. The time-domain simulation of thestudy system is presented by using MATLAB Simulink to testthe system robustness, to validate the proposed model and toshow the enhanced tracking capability

Assessing degradation of nano drug carriers - Magnetic particle imaging as a solution

Stimulus-triggered drug release by magnetic actuation of nano drug carriers is of high interest for targeted therapies. Most promising candidates are nano formulations based on biodegradable polymers and magnetic nanoparticles (MNP) because they have low side effects and customizable degradation properties. For the control drug release in vivo, monitoring of degradation dynamics play an important role. In this study, we demonstrate the feasibility of measuring degradation state of poly-(lactic-co-glycolic) acid magnetic nanoparticles (PLGA-MNP) using magnetic particle imaging (MPI). We show that due that the immobilization state of MNP during degradation leads to changes in image quality. Further, we test the influence of magnetic fluid hyperthermia on degradation of PLGA-MNP carriers and discuss the effects of degradation on MPI signal

MPI visualization of hybrid implant fibers using different system matrices

Hybrid stents can be used in cardiovascular applications and in hollow organ tumor therapy. They open the occluded area and can induce local hyperthermia by application of an alternating magnetic field (AMF) destroying cancer cells. Here, we investigate hybrid fibers made of polypropylene (PP) fibers with incorporated magnetic nanoparticles (MNP) via magnetic particle imaging (MPI). An influence of the MNP mobility and MNP agglomeration state as well as the orientation of elongated MNP agglomerations with respect to the drive field of the system matrix reference on the image reconstruction were determined. Best image resolution for a phantom consisting of two parallel fibers was achieved with reconstructions using system matrices of a fiber where MNP agglomerations point in the same direction as the ones of the phantom with respect to the drive field. Changes in MNP mobility, agglomeration state and their preferred directions have effects on the resulting image quality and must be considered in future measurements of complex structures of hybrid fibers

Linear structures of magnetic nanoparticles in hyperthermia and magnetic particle imaging

The development of theranostic devices combining magnetic particle imaging (MPI) and magnetic hyperthermia opens new possibilities for clinical applications of magnetic nanoparticles (MNP), e.g., hyperthermia-mediated drug delivery. Enhancing MNP performance for such applications can be achieved by using linear structures of MNP (i.e. chains, elongated clusters) instead of randomly distributed MNP. Here, we investigate the hyperthermia and MPI performance of two types of MNP linear structures: one generated by exposing MNP to a static magnetic field inside a hydrogel and the other by extruding a mixture of polypropylene and MNP to hybrid fibers. For both types of linear structures, an increase in heating efficiency and MPI signal was observed when the linear structure orientation is in the direction of the excitation field. In summary, the generation of MNP linear structures is a promising approach to increase their performance in MPI and magnetic hyperthermia. For MPI image reconstruction, the orientation of the linear structures relative to the drive field direction should be considered

Neuromodulation of chronic headaches: position statement from the European Headache Federation

The medical treatment of patients with chronic primary headache syndromes (chronic migraine, chronic tension-type headache, chronic cluster headache, hemicrania continua) is challenging as serious side effects frequently complicate the course of medical treatment and some patients may be even medically intractable. When a definitive lack of responsiveness to conservative treatments is ascertained and medication overuse headache is excluded, neuromodulation options can be considered in selected cases.Here, the various invasive and non-invasive approaches, such as hypothalamic deep brain stimulation, occipital nerve stimulation, stimulation of sphenopalatine ganglion, cervical spinal cord stimulation, vagus nerve stimulation, transcranial direct current stimulation, repetitive transcranial magnetic stimulation, and transcutaneous electrical nerve stimulation are extensively published although proper RCT-based evidence is limited. The European Headache Federation herewith provides a consensus statement on the clinical use of neuromodulation in headache, based on theoretical background, clinical data, and side effect of each method. This international consensus further gives recommendations for future studies on these new approaches.In spite of a growing field of stimulation devices in headaches treatment, further controlled studies to validate, strengthen and disseminate the use of neurostimulation are clearly warranted. Consequently, until these data are available any neurostimulation device should only be used in patients with medically intractable syndromes from tertiary headache centers either as part of a valid study or have shown to be effective in such controlled studies with an acceptable side effect profile