Dynamic Modeling and Simulation of a STATCOM/SMES Compensator in Power Systems

The advent of Flexible AC Transmission Systems (FACTS) is giving rise to a new family of electronic equipment emerging to controlling and optimizing the performance of power system, e.g. STATCOM. Static synchronous compensator (STATCOM) is one of the most widely used FACTS devices. This paper presents the integration of STATCOM coupled with superconducting magnetic energy storage (SMES) device in order to provide power oscillation damping in power systems. The additional of energy storage allows the combined compensator to exchange both reactive and active power with the ac network and also capability of the STATCOM is enhanced. This paper describes the structure and characteristics of STATCOM/SMES. In addition, using a proper control scheme, STATCOM/SMES is tested on an IEEE 3-bus system and more effective performance of the presented STATCOM/SMES compensator is evaluated with alone STATCOM through the dynamic simulation by using PSCAD/EMTDC software

Dynamic Modeling and Simulation of a STATCOM/SMES Compensator in Power Systems

The advent of Flexible AC Transmission Systems (FACTS) is giving rise to a new family of electronic equipment emerging to controlling and optimizing the performance of power system, e.g. STATCOM. Static synchronous compensator (STATCOM) is one of the most widely used FACTS devices. This paper presents the integration of STATCOM coupled with superconducting magnetic energy storage (SMES) device in order to provide power oscillation damping in power systems. The additional of energy storage allows the combined compensator to exchange both reactive and active power with the ac network and also capability of the STATCOM is enhanced. This paper describes the structure and characteristics of STATCOM/SMES. In addition, using a proper control scheme, STATCOM/SMES is tested on an IEEE 3-bus system and more effective performance of the presented STATCOM/SMES compensator is evaluated with alone STATCOM through the dynamic simulation by using PSCAD/EMTDC software

Investigation of the Bed and Structural Slopes on Bed Shear Stress and Flow Characteristics around an Impermeable Groyne

In this paper, effects of the cross shore and groyne wall slopes on flow parameters around an impermeable groyne were considered using a three-dimensional numerical CFD model (i.e., FLUENT). The k-ε turbulence model was used to evaluate the Reynolds stresses. The model was first applied to a vertical groyne on a flat bed and the model results were compared with the relevant experimental data. The results of this numerical test showed good agreements with the corresponding experimental measurements, in terms of water elevation, velocity magnitudes and reattachment length. The model was then applied to a series of structures with different lateral wall slopes on various cross sectional bed slopes. The numerical model results revealed that by increasing the cross shore bed slope in any case of the structural slopes, the magnitude of the maximum velocity and bed shear stresses decreased. These values decreased further as the structural slope reduced

An automated method for analysis of microcirculation videos for accurate assessment of tissue perfusion

Abstract Background Imaging of the human microcirculation in real-time has the potential to detect injuries and illnesses that disturb the microcirculation at earlier stages and may improve the efficacy of resuscitation. Despite advanced imaging techniques to monitor the microcirculation, there are currently no tools for the near real-time analysis of the videos produced by these imaging systems. An automated system tool that can extract microvasculature information and monitor changes in tissue perfusion quantitatively might be invaluable as a diagnostic and therapeutic endpoint for resuscitation. Methods The experimental algorithm automatically extracts microvascular network and quantitatively measures changes in the microcirculation. There are two main parts in the algorithm: video processing and vessel segmentation. Microcirculatory videos are first stabilized in a video processing step to remove motion artifacts. In the vessel segmentation process, the microvascular network is extracted using multiple level thresholding and pixel verification techniques. Threshold levels are selected using histogram information of a set of training video recordings. Pixel-by-pixel differences are calculated throughout the frames to identify active blood vessels and capillaries with flow. Results Sublingual microcirculatory videos are recorded from anesthetized swine at baseline and during hemorrhage using a hand-held Side-stream Dark Field (SDF) imaging device to track changes in the microvasculature during hemorrhage. Automatically segmented vessels in the recordings are analyzed visually and the functional capillary density (FCD) values calculated by the algorithm are compared for both health baseline and hemorrhagic conditions. These results were compared to independently made FCD measurements using a well-known semi-automated method. Results of the fully automated algorithm demonstrated a significant decrease of FCD values. Similar, but more variable FCD values were calculated using a commercially available software program requiring manual editing. Conclusions An entirely automated system for analyzing microcirculation videos to reduce human interaction and computation time is developed. The algorithm successfully stabilizes video recordings, segments blood vessels, identifies vessels without flow and calculates FCD in a fully automated process. The automated process provides an equal or better separation between healthy and hemorrhagic FCD values compared to currently available semi-automatic techniques. The proposed method shows promise for the quantitative measurement of changes occurring in microcirculation during injury.http://deepblue.lib.umich.edu/bitstream/2027.42/112336/1/12880_2011_Article_161.pd

School health assessment tools: A systematic review of measurement in primary schools

Background. This systematic review aimed to investigate the psychometric properties of the school health's assessment tools in primary schools through COSMIN Risk of Bias checklist. We examined the studies that have addressed the measurement properties of school-health instruments to give a clear overview of the quality of all available tools measuring school health in primary schools. This systematic review was registered in PROPERO with the Registration ID: CRD42020158158. Method. Databases of EBSCOhost, PubMed, ProQuest, Wily, PROSPERO, and OpenGrey were systematically searched without any time limitation to find all full-text English journal articles studied at least one of the COSMIN checklist measurement properties of a school-health assessment tool in primary schools. The instruments should be constructed based on a school health model. The eligible studies were assessed by COSMIN Risk of Bias checklist to report their quality of methodology for each measurement property and for the whole study by rating high, moderate or low quality. Results. At the final screening just seven studies remained for review. Four studies were tool development, three of them were rated as ''adequate'' and the other study as ''very good''; five studies examined the content validity, three of them were appraised as ''very good'', and the two remaining as ''inadequate''. All seven studies measured structural validity, three of them were evaluated as ''very good'', three other were scored as ''adequate'', and the last study as ''inadequate''. All the seven studies investigated the internal consistency, five of them were assessed as ''very good'', one was rated as ''doubtful'', and the last one as ''inadequate''. Just one study examined the cross-cultural validity and was rated as ''adequate''. Finally, all seven studies measured reliability, two of them were rated as ''very good'' and the rest five studies were appraised as ''doubtful''. All rating was based on COSMIN checklist criteria for quality of measurement properties assessment. Conclusion. The number of studies addressing school health assessment tools was very low and therefore not sufficient. Hence, there is a serious need to investigate. Copyright © 2020 Kazemitabar et al

Elevated monocyte-specific type I interferon signalling correlates positively with cardiac healing in myocardial infarct patients but interferon alpha application deteriorates myocardial healing in rats

Monocytes are involved in adverse left ventricular (LV) remodelling following myocardial infarction (MI). To provid

Factors Affecting Asphalt Pavement Density and the Effect on Long Term Pavement Performance

The Kentucky Transportation Center, the Asphalt Institute, and the Kentucky Transportation Cabinet worked together in order to identify factors that affect asphalt pavement density, and to then evaluate their effect on long term pavement performance. By determining which variables are most influential to pavement performance (i.e. roller pattern, temperature when rolled, etc.), and then monitoring the attention given to those variables, Kentucky would be able to increase the service life of asphalt roadways by at least 25%, therefore saving as much as $30 million annually on a resurfacing budget of$129.2 million (2007), while still maintaining the current roadway level of service. Ensuring that the pavement roller is able to roll the surface at the appropriate temperature can result in increases in density of up to 4%. An asphalt mix having 11% voids failed at approximately 400,000 cycles @ 350 microstrains, compared to that same mix at 7% air voids failing at 600,000 cycles @ 350 microstrains, resulting in a lab fatigue life increase of 50%. Two primary results were found from this study. First, by ensuring the compaction roller reaches the pavement before the temperature is allowed to drop substantially, up to a 4% increase in density can be achieved. Second, by increasing density 4%, lab fatigue life can be increased by as much as 50%. From these results, by practicing proper construction techniques one could conservatively expect to see increases in the service life of an asphalt surface of up to 25% in the field

Elevated monocyte-specific type I interferon signalling correlates positively with cardiac healing in myocardial infarct patients but interferon alpha application deteriorates myocardial healing in rats

Contains fulltext : 198360.pdf (publisher's version ) (Open Access