The analysis of soft error in c-elements

Soft errors are a serious concern in state holders as it can cause temporarily malfunction of the circuit. C-element is one of the state holders that is used widely in the asynchronous circuit. In this paper, the investigation will focus on the vulnerability of two types of C-element towards soft errors. A framework has been proposed for the rate of error due to neutron spectrum energy that can cause failure in the state holder. Effective analysis has been conducted on two different C-elements at different nodes by using UMC90 nm technology and 180nm technology. Based on the vulnerability data, a method for assessing vulnerability on a different implementation of C-elements has been developed. From the obtained data, it can be concluded that SIL is more resistant towards soft errors. © 2018 Institute of Advanced Engineering and Science. All rights reserved

Flexibility-based anti-islanding protection of a microgrid integrated with power grid

The widespread adoption of Renewable Energy Resources (RER) and Plug-in Electric Vehicles (PEVs) in distribution systems has achieved a substantial energy share, allowing the microgrid to participate in the open market. In fact, the high penetrations of RER and PEVs have increased the importance of impact assessment involving system protection. A framework is presented in this paper for modeling the combined operations of RER based solar Photovoltaic (PV) systems and PEVs in a microgrid integrated with power grid. The paper also proposes a fault current limiter connected in parallel (anti-islanding protection) with the circuit breaker in the point of common coupling (PCC), thus providing current bypass circuit during abnormal conditions. The concept of the proposed scheme is validated under various operating conditions using a 24-hourly dynamic simulation. The results demonstrate the effectiveness of the proposed approach

Smart grid mechanism for green energy management: a comprehensive review

The smart grid is not a monolithic system, but rather is a collection of several renewable energy resources and enabling technologies in which, intelligent control is an integral part of its mechanism to improve the utilization of assets. The dynamic characteristics of a smart grid upgrade the conventional system requirements using advanced control strategies to provide continuous power to the load from intermittent renewable generation. The communication networks and control systems that enable the accommodation of distributed generation are crucial technologies in monitoring, protecting, and operating the smart grid in a centralized or decentralized manner. This paper improves the earlier published review articles by exploring the evolution of smart grids in light of renewable energy penetration with associated features. Then, the review gives an overview of notable research works in the literature aimed at developing the management and control of smart energy systems. The reader is provided with an in- depth analysis of advanced cloud computing, the internet of things, and blockchain technology with real examples for the related renewable energy projects in smart cities. Furthermore, a special interest has been paid to quantify the performance of communication technologies along with the protocols through the conceptual investigation of real cases using the optimized network engineering tools. The outcomes of the presented review can assist researchers to understand the driving mechanism of smart grid as a route to intelligently utilize renewable energy storage. It is concluded that the amalgamation of blockchain and artificial intelligence for renewable energy management is the key area where the avenue is still open for future research studies

A Coordinated Control Approach for DC link and Rotor Crowbars to Improve Fault Ride-Through of DFIG-Based Wind Turbine

Nowadays, most double fed induction generators (DFIGs)-based wind turbines are equipped with a rotor crowbar connected in parallel with the rotor side converter (RSC). The parallel rotor side crowbar (PRSC) is used to protect the RSC and dc-link capacitor by dissipating the rotor energy during grid fault condition. In this paper, two types of crowbar protections are used, one in the rotor winding and the second in the dc link. During the fault condition, the rotor winding crowbar connects in series with the rotor winding and RSC to decrease the RSC current and dissipate the rotor energy. The general PRSC does not have the ability to significantly decrease the over-current. To protect the semiconductor switches of RSC, DFIG should not be kept connected with the utility grids under severe faults. The dc-link capacitor crowbar (DCCC) operates only if the dc capacitor voltage exceeds a threshold level. Both the series rotor side crowbar (SRSC) and the DCCC operate in coordination with each other to protect RSC and dc link during fault condition, and improve the fault ride through of the DFIG. Using the proposed SRSC, RSC continues its operation to control the DFIG during fault condition. Thereby, the reactive power can be injected to support the voltage at the point of common coupling. The behavior of the DFIG is investigated when the combined crowbars are operating with the proposed coordinated control approach and results are presented

Wave reflection at the origin of a first-generation branch artery and target organ protection: the AGES-Reykjavik study

Excessive pressure and flow pulsatility in first-generation branch arteries are associated with microvascular damage in high-flow organs like brain and kidneys. However, the contribution of local wave reflection and rereflection to microvascular damage remains controversial. Aortic flow, carotid pressure, flow and hydraulic power, brain magnetic resonance images, and cognitive scores were assessed in AGES-Reykjavik study participants without history of stroke, transient ischemic attack, or dementia (N=668, 378 women, 69-93 years of age). The aorta-carotid interface was generalized as a markedly asymmetrical bifurcation, with a large parent vessel (proximal aorta) branching into small (carotid) and large (distal aorta) daughter vessels. Local reflection coefficients were computed from aortic and carotid characteristic impedances. The bifurcation reflection coefficient, which determines pressure amplification in both daughter vessels, was low (0.06 +/- 0.03). The carotid flow transmission coefficient was low (0.11 +/- 0.04) and associated with markedly lower carotid versus aortic flow pulsatility (waveform SD, 7.2 +/- 2.0 versus 98.7 +/- 21.8 mL/s, P<0.001), pulsatility index (1.8 +/- 0.5 versus 4.5 +/- 0.6, P<0.001), and pulsatile power percentage (10 +/- 4% versus 25 +/- 5%, P<0.001). Transmitted as compared to incident pulsatile power (19.0 +/- 9.8 versus 35.9 +/- 17.8 mW, P<0.001) was further reduced by reflection (-4.3 +/- 2.7 mW) and rereflection (-12.5 +/- 8.1 mW) within the carotid. Higher carotid flow pulsatility correlated with lower white matter volume (R=-0.130, P<0.001) and lower memory scores (R=-0.161, P<0.001). Marked asymmetry of characteristic impedances at aorta-branch artery bifurcations limits amplification of pressure, markedly reduces absolute and relative pulsatility of transmitted flow and hydraulic power into first-generation branch arteries, and thereby protects the downstream local microcirculation from pulsatile damage.Neuro Imaging Researc

A comprehensive review of synchronization methods for grid-connected converters of renewable energy source

Recent interest in the integration of renewable energy sources (RES) into the power grid has raised concerns in synchronization of the various RES. Grid variables such as voltage, phase angle and frequency should be continuously monitored to guarantee correct operation and synchronization of power converters connected to the power grid. Numerous synchronization methods have been presented over the years to address issues such as unbalanced condition and frequency variation. This paper presents a review of past studies on synchronization methods for grid-connected converters together with their control and modeling techniques. Various estimation techniques for phase angle, frequency and harmonic are discussed and examined. Key challenges for a smart and efficient synchronization are briefly overviewed and possible future works are also recommended. A consolidated review is the particular focus of this paper, as is the provision of information on the best method for synchronizing grid-connected converters

Team dynamics in emergency surgery teams: results from a first international survey

Background: Emergency surgery represents a unique context. Trauma teams are often multidisciplinary and need to operate under extreme stress and time constraints, sometimes with no awareness of the trauma\u2019s causes or the patient\u2019s personal and clinical information. In this perspective, the dynamics of how trauma teams function is fundamental to ensuring the best performance and outcomes. Methods: An online survey was conducted among the World Society of Emergency Surgery members in early 2021. 402 fully filled questionnaires on the topics of knowledge translation dynamics and tools, non-technical skills, and difficulties in teamwork were collected. Data were analyzed using the software R, and reported following the Checklist for Reporting Results of Internet E-Surveys (CHERRIES). Results: Findings highlight how several surgeons are still unsure about the meaning and potential of knowledge translation and its mechanisms. Tools like training, clinical guidelines, and non-technical skills are recognized and used in clinical practice. Others, like patients\u2019 and stakeholders\u2019 engagement, are hardly implemented, despite their increasing importance in the modern healthcare scenario. Several difficulties in working as a team are described, including the lack of time, communication, training, trust, and ego. Discussion: Scientific societies should take the lead in offering training and support about the abovementioned topics. Dedicated educational initiatives, practical cases and experiences, workshops and symposia may allow mitigating the difficulties highlighted by the survey\u2019s participants, boosting the performance of emergency teams. Additional investigation of the survey results and its characteristics may lead to more further specific suggestions and potential solutions

A Framework for Placement Assessment of Synchrophasor Measurement in Practical Power Grid: A Case Study from Borneo

Security control of electricity networks has always been a key issue in the power industry development. An important approach towards full observability of power system is by means of using the phasor measurement unit (PMU). The consideration when applying PMU in power grid is the proper selection of its location. Therefore, an optimal location has to be identified in order to minimize the number of installed units, as it is not economically viable to place PMU at each bus. Firstly, this paper reviews the methods used for PMU placement. Further, the paper proposes a framework to evaluate the optimal locations of PMUs in a practical power grid consisting of 36 buses. The power grid has been modeled by taking into account the change in system configuration. Different optimal PMU placement (OPP) methods have been utilized to determine the best location with the lowest number of installed PMUs. The implemented framework for solving a practical problem using a classical approach has proven to be ideal in terms of ensuring the complete observability of the power system under single and multiple transmission line outages

Pendidikan Islam dalam Sistem Pendidikan Nasional di Indonesia

x, 208 hlm., 13.5x20.5 c