Hydrogen related risks within a private garage: concentration measurements in a realistic full scale experimental facility

ABSTRACT Next generation of hydrogen energy based vehicles is expected to come into widespread use in the near future. Various topics related to hydrogen including, production, storage, and application of hydrogen as an energy carrier, have become subjects of discussion in the framework of various European and International projects. Safety information is vital to support the successful introduction into mainstream and public acceptance of hydrogen as an energy carrier. One of such issues, which is seeking major attention is related to hydrogen powered vehicles parked inside a confined area (such as in a private garage). It is of utmost importance to predict, if uncontrolled release of hydrogen from a vehicle parked inside a confined area can create an explosive atmosphere. Subsequently, how the preventive measures can be implied to control these explosive atmospheres, if present inside a confined area? There is a little guidance currently developed for confined areas accommodating hydrogen fuelled vehicles. It is essential that mitigation measures for such conditions become established. Characterization of different scenarios those may arise in a real situation from hydrogen fuelled vehicle parked inside a garage and furthermore, the investigation of an optimal ventilation rate for hydrogen risk mitigation are some of the main objectives described in the framework of the present study. This work is an effort to provide detail experimental information's in view of establishing guidelines for hydrogen powered vehicles parked inside a private garage. The present work is developed in the framework of a European Network of Excellence HySafe and French project DRIVE. Present paper describes a purpose built realistic Garage test facility at CEA to study the dispersion of hydrogen leakage. The studied test cases evaluate the influence of injected volumes of hydrogen and the initial conditions at the leakage source on the dispersion and mixing characteristics inside the free volume of the unventilated garage. The mixing process and build-up of hydrogen concentration is measured for the duration of 24 hours. Due to safety reasons, helium gas is used to simulate the hydrogen dispersion characteristics

Prevention of surgical site infections in spine surgery: an international survey of clinical practices among expert spine surgeons

Study Design: Questionnaire-based survey.Objectives: Surgical site infection (SSI) is a common complication in spine surgery but universal guidelines for SSI prevention are lacking. The objectives of this study are to depict a global status quo on implemented prevention strategies in spine surgery, common themes of practice and determine key areas for future research.Methods: An 80-item survey was distributed among spine surgeons worldwide via email. The questionnaire was designed and approved by an International Consensus Group on spine SSI. Consensus was defined as more than 60% of participants agreeing to a specific prevention strategy.Results: Four hundred seventy-two surgeons participated in the survey. Screening for Staphylococcus aureus (SA) is not common, whereas preoperative decolonization is performed in almost half of all hospitals. Body mass index (BMI) was not important for surgery planning. In contrast, elevated HbAIc level and hypoalbuminemia were often considered as reasons to postpone surgery. Cefazoline is the common drug for antimicrobial prophylaxis. Alcohol-based chlorhexidine is mainly used for skin disinfection. Double-gloving, wound irrigation, and tissue-conserving surgical techniques are routine in the operating room (OR). Local antibiotic administration is not common. Wound closure techniques and postoperative wound dressing routines vary greatly between the participating institutions.Conclusions: With this study we provide an international overview on the heterogeneity of SSI prevention strategies in spine surgery. We demonstrated a large heterogeneity for pre-, peri- and postoperative measures to prevent SSI. Our data illustrated the need for developing universal guidelines and for testing areas of controversy in prospective clinical trails.Scientific Assessment and Innovation in Neurosurgical Treatment Strategie

Plateau facility in support to ASTRID and the sfr program: an overview of the first mock-up of the ASTRID upper plenum, MICAS

International audienceThe CEA and several industrial partners are involved in the development of a 4th generation reactor cooled by sodium, ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration). It is a 600MWe pool type reactor integrating cutting edge technologies.Developments are in progress especially for the vessel and the apparatus. Experiments are needed for both validation of numerical codes and specific studies. In this way, a thermal-hydraulic loop, the PLATEAU facility, has been developed and built at the CEA Cadarache. Different mock-ups can be connected to this loop to study the different issues at various reactor conditions. Currently, 4 mock-ups are identified the internal vessel, the entire pool reactor, the link between the external and the internal vessel, a part of the internal vessel at a higher scale to study specific issues.The MICAS mock-up at 1/6 scale is dedicated to study the flow regime of the internal vessel (hot plenum), both for code validation and also engineering design development.This mock-up has been built in transparent polymer to carry out some optical measurements as laser velocimetry. Numerical studies have been engaged to determine the general flow pattern in a way to identify the area of interest for detailed phenomenological studies

Änderung dес säurе-basen-status und des humusgehaltes in den hintergrundboden des industriegebietes am gubkin bezirk im gebiet Belgorod

yesDer artikel enthält eine vergleichende studie von neuland schwarzerde und Ackerschwarzerde im industriegebiet am Gubkin Bezirk des Belgoroder GebietesBelgorod State Universit

International Standard Problem on containment thermal-hydraulics ISP47 - STEP1 - Results from the MISTRA exercise

International audienceThe understanding of hydrogen distribution during severe accidents in a nuclear reactor containment is still an open issue. Several containment thermal-hydraulics international standard (ISP) have been conducted to address this topic. However the predictions made by the available Lumped Parameter or CFD computer codes were generally not satisfactory. Therefore a new exercise was launched in 1999 using new state-of-the-art experimental facilities TOSQAN, MISTRA and ThAI that included sophisticated 3D instrumentation and well controled boundary conditions. Predictive capabilities of important and still uncertain phenomena such as wall condensation, natural circulation and gas stratification are assessed. In addition, comparison between LP and CFD codes and assessment of the capability of CFD codes to deal with scaling effects are performed. This article reports on the part of the exercise which concerns the MISTRA facility includind experimental results and blind benchmark exercises

Änderung dес säurе-basen-status und des humusgehaltes in den hintergrundboden des industriegebietes am gubkin bezirk im gebiet Belgorod

Der artikel enthält eine vergleichende studie von neuland schwarzerde und Ackerschwarzerde im industriegebiet am Gubkin Bezirk des Belgoroder GebietesyesBelgorod State Universit