Sufficient Safety Research Articles

Design and Evaluation of Lane-Change Collision Avoidance Systems in Semi-Automated Driving

Hands on the steering wheel partial driving automation, in which the system controls the lateral and longitudinal vehicle motion while the driver holds the steering wheel, monitors the roadway, and intervenes when necessary, is an example of shared control driving. To insure mutual safety in shared control driving, the system also needs to guide the driver's interventions to avoid hazardous actions, such as risky lane changes. This study proposes three steering interventions that activate automatically when the system detects a lane change by monitoring the steering wheel angle inputted by the driver and road section and determining that the two vehicles are on a collision course. A driving simulation experiment with 80 drivers was conducted to compare four conditions: 1) no steering intervention; 2) a haptic steering intervention that increases stiffness against steering toward the lane where a collision may occur; 3) an automatic steering intervention that decouples the driver's steering input and autonomously steered the vehicle away from the hazard; and 4) multiple steering interventions that generate different degrees of haptic and automatic steering interventions based on the time headway and time-to-collision between vehicles. Analysis of driving performance and safety under conditions with and without steering interventions indicate that all participants, at some points, initiated lane changes that are likely to result in a crash during partial driving automation. However, the three interventions effectively reduced lane-change collisions compared to the baseline. While the automatic steering intervention avoided all collisions, the multiple steering interventions were determined to provide sufficient safety while being more thoroughly accepted by the drivers than the haptic and automatic interventions separately. These findings have implications for developing adaptive collision avoidance systems considering user preference and driving performance.

ISD소송 사례를 통해 본 충분한 보호 및 안전의 판단 기준에 관한 연구

With the development of BIT, the regulation of 'sufficient protection and safety' was introduced to protect and promote foreign investment. Sufficient protection and safety regulations have traditionally been limited to protecting investors and investment from physical damage and threats from troops, soldiers, and rebel workers in investment host countries. Cases applying sufficient protection and safety have dealt with damage to the physical assets of investors committed by third parties unless the governments of investment host countries exercise significant care in preventing damage or punishing actors. Regarding the meaning of ‘due diligence’, the arbitral tribunal has mentioned that due diligence is no more than or less reasonable precautions that are expected to be exercised by a legitimately operated government in similar situations. There are many cases in which the 'sufficient protection and safety' regulation is interpreted as a broad concept that includes providing legal stability as well as physical protection. It is difficult to say that a sufficient consensus has been formed on whether the ‘sufficient protection and safety’ standard should provide a business environment or legal stability in excess of the country's obligation to provide simple physical safety for foreign investors and investments. Furthermore, even if the scope of application of this provision is widely interpreted, the state cannot even take issue with exercising its legitimate regulatory authority to achieve reasonable policy purposes. The obligation to provide sufficient protection and safety for foreign investment is to protect investors from bullying by third parties or state actors, but banning regulations or legislation that affect investors should not be interpreted.

Interference of cardiac implantable electronic devices and computed tomography imaging in the current era with a phantom model.

Cardiac implantable electronic devices are used in patients with cardiac rhythm disorders. Computed tomography irradiation is not prohibited for patients with cardiac implantable electronic devices, despite adverse events being reported. Hence, appropriate preparation and knowledge are required before computed tomography irradiation can be carried out in these patients. Since there is limited knowledge or literature about the influence of computed tomography irradiation in cases with recent cardiac implantable electronic devices, we aimed to evaluate the adverse events and elucidate the necessary and sufficient safety measures associated with this therapy. We placed cardiac implantable electronic devices on an anthropomorphic phantom model and observed their electrical activity in electrograms, while various protocols of computed tomography irradiation were implemented and adverse events evaluated. Oversensing with pauses of up to 3.2 s was observed in standard computed tomography protocols, but ventricular tachyarrhythmia or other clinically significant events could not be confirmed. Oversensing with pauses of up to 8.0 s was observed and ventricular tachyarrhythmia was detected in the maximum-dose protocols. However, treatments such as antitachycardia pacing or shock therapy for ventricular tachyarrhythmia were not observed because of their absence. Computed tomography irradiation for patients using cardiac implantable electronic devices is highly unlikely to cause clinically significant adverse events with the device settings and computed tomography protocols currently being used. Changing or monitoring the device settings routinely before computed tomography irradiation is not necessarily required for most patients.

Safety and Protective Effects of Influenza Vaccination in Pregnant Women on Pregnancy and Birth Outcomes in Pune, India: A Cross-Sectional Study.

Maternal influenza vaccination provides effective protection against influenza infections in pregnant women and their newborns. In India, the influenza vaccine has not yet been offered through immunization programs, owing to the lack of sufficient safety data for pregnant Indian women. This cross-sectional observational study enrolled 558 women admitted to the obstetrics ward of a civic hospital in Pune. Study-related information was obtained from the participants through hospital records and interviews using structured questionnaires. Univariate and multivariable analysis was used, and the chi-square test with adjusted odds ratio was estimated to account for vaccine exposure and the temporal nature of each outcome, respectively. Women not vaccinated against influenza during pregnancy had a higher risk of delivering very LBW infants, and possible protective effects were suggested (AOR 2.29, 95% CI 1.03 to 5.58, p = 0.03). No association was observed between maternal influenza vaccination for Caesarean section (LSCS) (AOR 0.97, 95% CI, 0.78, 1.85), stillbirth (AOR 1.8, 95% CI 0.18, 24.64) and NICU admission (AOR, 0.87, 0.29 to 2.85), and congenital anomaly (AOR, 0.81, 0.10 to 3.87). These results show that the influenza vaccine administered during pregnancy is safe and might lower the risk of negative birth outcomes.

Assessing code-based design wind loads for offshore wind turbines in China against typhoons

In the areas prone to severe typhoons, such as the south and southeast China waters, offshore wind turbine design will most likely fall into Class-S, but the current design standards have not treated much detail on the technical parameters under the typhoon-induced conditions to guide the structural design. This study set out to investigate the feasibility of extreme wind conditions in existing standards for offshore wind turbines in the south and southeast China waters. The extreme wind conditions in existing standards and actual typhoon cases in the south and southeast China waters were used to compare and analyze the typhoon-induced wind effect on offshore wind turbines. This study supports evidence from previous views that the extreme wind condition specified by existing design standards does not provide a sufficient safety margin for the south and southeast China waters use. Another interesting finding is that from the perspective of the typhoon-resistant design of large-scale offshore wind turbines in the future, it is more inclined to abandon the height of the hub and use the height of 10m as the reference wind speed height to obtain a more reasonable wind speed field as input conditions. The insights gained from this study may be of assistance to the typhoon-resistant design of customized offshore wind turbines in the south and southeast China waters and would help reduce the risks and economic losses of Class-S wind turbines in other typhoon-prone areas.

Development and design of the BELpREG registration system for the collection of real-world data on medication use in pregnancy and mother-infant outcomes

Although medication use during pregnancy is common, most available products lack sufficient safety information. As prospective data collection and perinatal pharmacoepidemiologic research on medication safety in pregnancy did not exist in Belgium yet, the BELpREG data registration system was developed. BELpREG enables comprehensive “real-world” data collection on perinatal medication use and mother-infant outcomes via online questionnaires that are completed by pregnant women every 4 weeks during pregnancy and in the first 8 weeks after childbirth. This paper describes the development and current design of the BELpREG system, including the list of BELpREG variables. To compile this list of variables, relevant documents were explored, followed by consultation of an interdisciplinary expert panel. The included variables were structured in seven categories: 1) Sociodemographic characteristics; 2) Information on the current pregnancy and health status; 3) Maternal-obstetric history; 4) Use of medicines, folic acid/pregnancy vitamins and other health products; 5) Substance use; 6) Pregnancy outcomes; and 7) Neonatal outcomes. An electronic informed consent and linkage to medication databases, with images of drug packages and underlying structured data fields, are built into the system. Data collection has officially started in November 2022. Based on its rigorous design, BELpREG holds the potential to be a successful and sustainable research tool, enabling perinatal pharmacoepidemiologic research in Belgium and beyond.

Mechanical properties analysis of joints for prefabricated metro station structure based on Whole-process in-situ monitoring

Changchun Metro Line 2 implemented the whole-process monitoring and measurement of prefabricated metro station for the first time. This paper analyzes the mechanical behavior and deformation of the joints of vault and arch springing, which bear high bending moments, in order to study the mechanical properties of these joints, which play a key role in the bearing capacity of prefabricated structure. In addition, it also discusses the trend of the joint stress, relative deformation and relative rotation angle as it changes with the construction process and after opening for traffic. Furthermore, it analyzes the performance of the joints in different construction stages, and compares it with the numerical calculation results based on the long-term in-situ monitoring and survey data carried out at the prefabricated station of Changchun Metro during the whole construction period. As indicated by the result, at the beginning of the assembly and arching into a ring of the components at the top, the structure undergoes a self-adaptation period, where the joints are subject to heavy stress and deformation. After backfilling and water level recovery, the joints are subject to increased axial force and reduced stress and deformation, resulting in a positive effect on the bearing capacity of the joints. The overall change range in joint stress is rather small. During the construction period, the two tenons of double-tenon joint of vault bear external force by mutual engagement, which are subject to two types of stresses, namely, tensile stress and compressive stress. The concave-convex tenon of single-tenon joint at the arch springing is markedly engaged with each other, with the tenon subject to a bending effect. The test results are relatively stable, and the overall deformation at the joint of vault and arch springing is relatively small, with sufficient safety margin from the end of construction disturbance through the operation stage till today. The research results demonstrate great practical guiding significance for the joint and structure design of prefabricated metro station.

Energy-based seismic design and assessment of ductile linked rocking steel frame

Ductile linked rocking steel frame (DLRF) is an innovative and efficient structural system that combines two gravity-controlled rocking steel braced frames with corrugated steel plate links. DLRF is designed to dissipate input seismic energy through the uplifting and yielding of the rocking column base and yielding of the corrugated steel plate link. To ensure the DLRF can achieve superior seismic performance at various shaking intensities, the equivalent energy design procedure (EEDP) is adopted to design DLRF. In this paper, two prototype DLRF buildings (3 - and 6 - story) were designed using EEDP. Robust numerical models were established to verify the seismic performance of the DLRF. Nonlinear dynamic analyses confirm that the DLRF designed using EEDP can achieve the desired performance objectives at different levels of earthquake shaking intensities. In addition, the results of the incremental dynamic analyses show that DLRF has a sufficient safety margin against collapse. Hence, DLRF can be used as an alternative seismic force-resisting system.

"It's Just a Checklist": Examining the Needs of Occupational Health and Safety Training for New Immigrant Workers in Canada.

New immigrant workers (NIWs) are overrepresented in hazardous workplaces. Sufficient Occupational Health and Safety (OH&S) training could minimize workplace injuries. This study aims to identify the current status of OH&S and training for NIWs in Canada. Generic qualitative research was conducted. Seven NIWs and nine service providers were interviewed to understand OH&S issues, perceptions on rules and regulations, and expectations for training. Thematic analysis was used for data analysis. Four themes that affect OH&S for NIWs include attitudes toward safety and training, personal barriers, Canadian workplace culture, and macrolevel interconnected systems. Three needs on OH&S training are increasing accessibility, ensuring full understanding, and building confidence. Current training does not mitigate safety risks in workplaces, and NIWs do not feel empowered to exercise their rights. New training protocols would be beneficial to equip NIWs to enter the workforce.

Orally Bioavailable Macrocyclic Peptide That Inhibits Binding of PCSK9 to the Low Density Lipoprotein Receptor.

Inhibition of PCSK9 (proprotein convertase subtilisin/kexin type 9)-low density lipoprotein receptor interaction with injectable monoclonal antibodies or small interfering RNA lowers plasma low density lipoprotein-cholesterol, but despite nearly 2 decades of effort, an oral inhibitor of PCSK9 is not available. Macrocyclic peptides represent a novel approach to target proteins traditionally considered intractable to small-molecule drug design. Novel mRNA display screening technology was used to identify lead chemical matter, which was then optimized by applying structure-based drug design enabled by novel synthetic chemistry to identify macrocyclic peptide (MK-0616) with exquisite potency and selectivity for PCSK9. Following completion of nonclinical safety studies, MK-0616 was administered to healthy adult participants in a single rising-dose Phase 1 clinical trial designed to evaluate its safety, pharmacokinetics, and pharmacodynamics. In a multiple-dose trial in participants taking statins, MK-0616 was administered once daily for 14 days to characterize the safety, pharmacokinetics, and pharmacodynamics (change in low density lipoprotein cholesterol). MK-0616 displayed high affinity (Ki = 5pM) for PCSK9 in vitro and sufficient safety and oral bioavailability preclinically to enable advancement into the clinic. In Phase 1 clinical studies in healthy adults, single oral doses of MK-0616 were associated with >93% geometric mean reduction (95% CI, 84-103) of free, unbound plasma PCSK9; in participants on statin therapy, multiple-oral-dose regimens provided a maximum 61% geometric mean reduction (95% CI, 43-85) in low density lipoprotein cholesterol from baseline after 14 days of once-daily dosing of 20 mg MK-0616. This work validates the use of mRNA display technology for identification of novel oral therapeutic agents, exemplified by the identification of an oral PCSK9 inhibitor, which has the potential to be a highly effective cholesterol lowering therapy for patients in need.

Multiphysics simulations of Self-Regulating performance of an optimized molten metal fuel microreactor design

Advanced microreactors are expected to play an indispensable role in reliable energy solutions for civilian/military applications in off-grid regions and space applications such as power supplies for Lunar and Mars bases. An innovative fast neutron spectrum heat pipe microreactor (HP-MR) concept was recently proposed with two unique features: molten U-Mn fuel and heat pipes as the heat removal mechanism. The microreactor was designed to be self-regulated, solely relying on reactivity feedbacks from fuel temperature. The reactor design has been further optimized to provide sufficient engineering safety margin and effective heat removal. In this study, the self-regulating performance of the optimized molten metal fuel microreactor was investigated by multiphysics simulations (neutronics, heat-transfer and heat pipe modeling) based on the MOOSE MultiApps system. The responses of the reactor to a series of transient scenarios were simulated to demonstrate the exceptional and inherent safety features of the novel microreactor concept.

Dynamic Simulation and Research of Land-Based Missile Tilt Launch Platform

In order to study the influence of the structural factors of the launch device on the missile tilt projectile dynamics, a dynamic model of the missile tilt launch platform was established based on the finite element method. The effects of shock absorber stiffness, angle between shock absorber and horizontal plane and tilt of the launch device were studied on the missile and launch platform’s ejection response characteristics. The research results show that the greater the rigidity of the shock absorber, the smaller the angle between the shock absorber and the horizontal plane, and the smaller the vibration amplitude of the initial disturbance of the missile and the launch cylinder; when the tilt angle of the launch device is within 6 °, the angle change has a smaller impact on the speed of the missile outlet, and there is a sufficient safety distance between the missile and the launch canister during the launch process. The larger the vibration amplitude of the initial disturbance and the launch tube. The research results can provide a theoretical reference for the design and optimization of the tilted launch platform.

A Case of de novo MPO-associated Central Nervous System Vasculitis Following Heterogeneous mRNA1273 COVID-19 Booster Vaccination

The coronavirus disease-19 (COVID-19) pandemic leaded to inevitable expeditious vaccine rollout without sufficient safety profile. Especially, severe acute respiratory syndrome coronavirus 2 infection has known to induce overreacted immune responses such as releasing of proteinase-3 and myeloperoxidase (MPO) by neutrophil. This overreacted immune response leads to the concern of the development of autoimmune diseases after COVID-19 vaccination. We report the case of de novo MPO-associated systemic vasculitis involving central nervous system following heterogeneous mRNA1273 COVID-19 booster vaccination.

CAUSES, IMPACTS & MITIGATION MEASURES FOR FLASH FLOODS IN INDIAN HIMALAYAN REGION

The Himalayas is the crown of India but Because of its inherent characteristics and climatic conditions, the young Indian Himalayan region is vulnerable to a variety of natural disasters. Risks include varying degrees of earthquake severity, floods or flash floods, and glacial lake eruptions. The Uttarakhand flash flood of 2013 caused by a glacial lake outburst is considered the worst disaster of the decade. Flash flood 2021 Chamoli (Uttarakhand) caused by an avalanche, Amarnath flash flood July 2022 caused by a cloud burst, Leh flash flood 2010 caused by a cloud burst are some recent examples of flash floods in the Indian Himalayan region which shows that flash floods are getting frequent in hilly regions. The best use and exploitation of land and water resources are provided through flood risk management, which is essential for a nation's economy and sustainable development. In India, measures have been developed to lessen the negative consequences of flooding in plains by emphasizing flood risk management. However, due to the difficult terrain, restricted accessibility, and low degree of monitoring, flood risk management in hilly areas is still in its early stages. The last several decadal floods have demonstrated that only building safeguards alone could not provide sufficient safety from such catastrophes. There is a need for a such framework that can efficiently manage these calamities. The research aims to analyze the various causes that trigger flash floods in hilly regions, the consequences of such events, and their level of impact. The study discusses various guidelines, policies, and strategies for risk reduction to analyze the gap & challenges that are crucial in effective flood management. Keywords: GLOF, Flash Floods, mitigation measures, Himalayan Regions, IHR, Risk Reduction, Uttarakhand, Kedarnath,

Patient perspectives on non-response to psychotherapy for borderline personality disorder: a qualitative study

BackgroundDespite increasing evidence for the effectiveness of psychotherapy for Borderline Personality Disorder (BPD), estimates show that approximately half of those in treatment do not clinically improve or reach reliable change criteria. There are limited qualitative descriptions of treatment factors associated with non-response from the perspectives of those struggling to improve.MethodEighteen people (72.2% female, mean age 29.4 (SD = 8)) with experience of receiving psychotherapeutic treatment for BPD were interviewed to obtain their perspectives on hindering factors in treatment and what may be helpful to reduce non-response. The data in this qualitative study was analysed thematically.ResultsFour domains were created from the insights patients shared on non-response and what may be needed to mitigate it. The focus of Domain 1 was that therapy cannot be effective until two factors are in place. First, the patient needs sufficient safety and stability in their environment in order to face the challenges of therapy. Second, they need to be able to access therapy. Domain 2 described factors the patients themselves contribute. The themes in this domain were described as phases that need to be progressed through before therapy can be effective. These phases were ceasing denial that help is warranted and deserved, taking responsibility for behaviours that contribute to unwellness, and committing to the hard work that is required for change. Domain 3 described how the lack of a safe alliance and ruptures in the safety of the relationship with the therapist can contribute to non-response. Domain 4 was comprised of factors that patients identified as supportive of moving through the barriers to response. The first theme in this domain was prioritising the safety of the therapy relationship. The second theme was giving a clear diagnosis and taking a collaborative approach in sessions. The final theme described the importance of focusing on practical goals with the patient to create tangible life changes.ConclusionThis study found that non-response is complex and multifaceted. First, it is clear that systems need to be in place to support access to adequate care and foster life stability. Second, considerable effort may be needed at the engagement phase of therapy to clarify expectations. Third, attention to specific interpersonal challenges between patients and therapists is an important focus. Finally, structured work to improve relationships and vocational outcomes is indicated.

Reliability-Based Proof Load Factors for Assessment of Bridges

Advanced reliability assessment can be required when evaluating existing bridge structures through proof load testing. The target load of a proof load test typically requires input from resistance models; however, bridges with a low documentation level are often the most relevant for proof load testing, and resistance models thus involve significant uncertainties. This paper presents a different approach to proof loading and target proof load, in which the resistance model is not included in the determination of this load. Instead, the target proof load is determined based on load models coupled to the desired target failure probability, thus ensuring sufficient safety of the existing bridge. The method is in line with the proposal for a new Eurocode on assessment of existing structures and is deemed to be superior to existing approaches. An essential assumption of the method is that monitoring systems can identify stop criteria before irreversible damage occurs. The approach was applied in a case study, where an OT-slab bridge with a span of 6.5 m was proof-load-tested and reclassified for capacity upgrading of a road stretch in Denmark.

Abstract LB121: BrainChild-03: Intraventricular B7-H3 CAR T cells for recurrent/refractory central nervous system tumors and non-pontine diffuse midline glioma in children and young adults

Abstract Background: B7-H3 expression on central nervous system (CNS) tumors offers a potential therapeutic target for adoptive cellular therapy. Methods: A 3+3 statistical design was employed to assess the safety of repeated B7-H3 chimeric antigen receptor (CAR) T cells administered into the intracranial ventricular system (ICV) using an intrapatient dose escalation without lymphodepleting chemotherapy in pts 1-26 years of age with recurrent/refractory CNS tumors including (non-pontine) diffuse midline glioma (DMG) (NCT04185038, Arm B). Primary endpoints were feasibility to manufacture sufficient CARs and safety of weekly infusions for 3 weeks of 4-week cycles for 2 cycles. Secondary endpoints were best overall response (BOR) and correlatives of CAR activity. Results: CAR manufacturing was achieved in 20/22 (91%) enrolled pts. Eight pts were inevaluable (rapidly progressive exam precluding initial infusion (n=5), removal from protocol therapy due to progressive disease (n=2), and lack of evaluable disease prior to initial infusion (n=1)). No dose limiting toxicities were observed, identifying the maximally tolerated dose regimen (MTDR) as DR3 (maximum dose: 10 × 107 B7-H3CARs). Subjects received 98 ICV doses (median: 6 doses/patient, range: 3-13). For evaluable patients, the most common adverse events were headache (12/12, 100%), fatigue (9/12, 75%), nausea/vomiting (7/12, 58%), and fever (6/12, 50%). There was no cytokine release syndrome (CRS) or immune effector cell-associated neurotoxicity syndrome (ICANS). Imaging analysis is ongoing with current BOR being stable disease. CAR T cells were detected in the CSF in 9/12 evaluable pts (75%). Serial CSF/serum cytokine analysis and mass spectrometry are in process. Conclusion: Repeated ICV administration of B7-H3 CAR T cells is tolerable with circulating CAR T cells detectable in the CSF post infusion. Further investigation is warranted, along with future studies interrogating iterative enhancements such as modifications for enhanced potency and multi-antigen targeting. Citation Format: Nicholas A. Vitanza, Juliane Gust, Rebecca Ronsley, Ashley L. Wilson, Wenjun Huang, Kristy Seidel, Catherine M. Albert, Navin Pinto, Rimas J. Orentas, Rebecca A. Gardner, Michael C. Jensen, Julie R. Park. BrainChild-03: Intraventricular B7-H3 CAR T cells for recurrent/refractory central nervous system tumors and non-pontine diffuse midline glioma in children and young adults [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB121.

Radiofrequency ablation of benign thyroid nodules: the value of anterolateral hydrodissection.

This study aimed to evaluate the technical feasibility, efficacy, and safety of anterolateral hydrodissection (ALHD) in radiofrequency ablation (RFA) for benign thyroid nodules. Between November 2019 and April 2020, 39 patients underwent 41 sessions of RFA with the ALHD technique to treat benign thyroid nodules. ALHD was performed with cold (0°C-4°C) 5% dextrose solution during RFA to minimize pain and secure sufficient safety margins from critical neck structures. The initial ablation ratio (IAR) was measured to assess the technique's efficiency. Ultrasound examinations, symptoms, and cosmetic scores were evaluated pre-procedure and at 6 and 12 months post-procedure. Procedure-related pain during RFA and complications were recorded. The mean index nodule volume was 20.5±21.6 mL. ALHD was technically feasible in all patients. The mean IAR was 90.7%±8.3%, and significant reductions in mean nodule volume were noted at 6- and 12-month follow-ups (P<0.001, 63.9%±19.0%, and 76.3%±18.9%, respectively). Symptom and cosmetic scores showed significant improvements at 6- and 12-month follow-ups (P<0.001). Pain during the procedure was well-controlled with ALHD in all patients. After the initial use of 5-10 mL of lidocaine at the start of the procedure, no further lidocaine injection was given to any patient. Transient voice change was observed in one patient, but the patient recovered spontaneously within 30 minutes. The ALHD technique was technically feasible and effective in all patients, achieving a mean IAR of 90.7%. The ALHD technique also had a pain-relieving effect, resulting in only low amounts of lidocaine administration being required during the procedure.

Hybrid Line Commutated Converter With Fast Commutation Characteristic Based on IGCT for HVDC Application: Topology, Design Methodology, and Experiments

In order to effectively mitigate commutation failure of line commutated converter (LCC), a concept of hybrid converter is proposed. The converter replaces a part of the thyristors by the integrated gate commutated thyristors (IGCT). In this article, the hybrid line commutated converter is further developed and reverse blocking IGCTs (RB-IGCT) are applied in each bridge arm to achieve fast commutation characteristic. RB-IGCT is capable of withstanding bidirectional voltages, and owing to the device control method of self-turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> , has almost zero commutation time and gives play to the advantage of fast commutation, thus earning recovery time for the thyristors. Therefore, the commutation performance of the hybrid converter is enhanced greatly. The topology, control strategy, and the hybrid device characterization analysis with fast commutation are introduced. On the basis, the design methodology of hybrid line commutated converter with fast commutation characteristic (FC-LCC) is presented. Finally, the simulation results based on CIGRE standard system and experimental results of a 30 kV/4.5 kA FC-LCC prototype verify the proposed converter's effectiveness and correctness and the fast commutation characteristic can provide sufficient safety time margin for system. The converter shows promising prospects for high voltage direct current system and has significant value for engineering application.

Influence of heavy concrete on seismic response of transfer and purging rooms of nuclear power plant

The high-density characteristic of heavy concrete is the main factor affecting its excellent radiation protection performance. The heavy concrete commonly used in the nuclear power plant structure are hematite concrete and barite concrete. Based on the finite element method, the finite element models of three transfer and purging rooms of nuclear power plant were established. The models used C40 ordinary concrete, C40 hematite concrete and C40 barite concrete respectively. Modal analysis and seismic response time history analysis were carried out for the three models to discuss the dynamic response characteristics and seismic performance of the transfer and purging rooms, and to analyze the influence of heavy concrete on the natural vibration characteristics and seismic response of the transfer and purging rooms. The results show that the structural stiffness of the transfer and purging rooms is large, the natural vibration period is short, the response to the ground motion is small, and the structure is still working in an elastic state, and the hematite concrete has little effect on the natural vibration characteristics and seismic response of the transfer and purging rooms, while the barite concrete can significantly prolong the natural vibration period of the transfer and purging rooms and amplify the seismic response of the structure. The structure of transfer and purging rooms has a sufficient safety margin, and the transfer and purging rooms using heavy concrete can fully meet the requirements of structural seismic performance.