The application of microorganisms as probiotics is limited due to lack of safety evaluation.Here,a novel multi-stress-tolerant yeast Meyerozyma guilliermondii GXDK6 with aroma-producing properties was identified from ...The application of microorganisms as probiotics is limited due to lack of safety evaluation.Here,a novel multi-stress-tolerant yeast Meyerozyma guilliermondii GXDK6 with aroma-producing properties was identified from marine mangrove microorganisms.Its safety and probiotic properties were assessed in accordance with phenotype and whole-genome sequencing analysis.Results showed that the genes and phenotypic expression of related virulence,antibiotic resistance and retroelement were rarely found.Hyphal morphogenesis genes(SIT4,HOG1,SPA2,ERK1,ICL1,CST20,HSP104,TPS1,and RHO1)and phospholipase secretion gene(VPS4)were annotated.True hyphae and phospholipase were absent.Only one retroelement(Tad1-65_BG)was found.Major biogenic amines(BAs)encoding genes were absent,except for spermidine synthase(JA9_002594),spermine synthase(JA9_004690),and tyrosine decarboxylase(inx).The production of single BAs and total BAs was far below the food-defined thresholds.GXDK6 had no resistance to common antifungal drugs.Virulence enzymes,such as gelatinase,DNase,hemolytic,lecithinase,and thrombin were absent.Acute toxicity test with mice demonstrated that GXDK6 is safe.GXDK6 has a good reproduction ability in the simulation gastrointestinal tract.GXDK6 also has a strong antioxidant ability,β-glucosidase,and inulinase activity.To sum up,GXDK6 is considered as a safe probiotic for human consumption and food fermentation.展开更多
A new safety assessment method for parallel routes is presented. From the aspects of safety guard system of air traffic control（ATC） and considering the flight conflict as causing event of air collision accidents, t...A new safety assessment method for parallel routes is presented. From the aspects of safety guard system of air traffic control（ATC） and considering the flight conflict as causing event of air collision accidents, this paper fosters a four-layer safety guard of controller command, short-term conflict alerts （STCAs）, pilot visual avoidance, and traffic alert collision avoidance system（TCAS）. Then, the problem of parallel routes collision risk is divided into two parts：the calculation of potential flight conflict and the analysis of failure probability of the four-layer safety guard. A calculation model for controller interference times is induced. By using cognitive reliability and error analysis method（CREAM）,the calculation problem to failure probability of controller sequencing flight conflicts is solved and a fault tree model of guard failure of STCA and TCAS is established. Finally, the Beijing-Shanghai parallel routes are taken as an example to be calculated and the collision risk of the parallel routes is obtained under the condition of radar control. Results show that the parallel routes can satisfy the safety demands.展开更多
In this paper,overcharge behaviors and thermal runaway(TR)features of large format lithium-ion(Liion)cells with different cathode materials(LiFePO4(LFP),Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_(2)(NCM111),Li[Ni_(0.6)Co_(0.2)Mn_...In this paper,overcharge behaviors and thermal runaway(TR)features of large format lithium-ion(Liion)cells with different cathode materials(LiFePO4(LFP),Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_(2)(NCM111),Li[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_(2)(NCM622)and Li[Ni_(0.8)Co_(0.1)Mn_(0.1)]O_(2)(NCM811))were investigated.The results showed that,under the same overcharge condition,the TR of LFP Li-ion cell occurred earlier compared with the NCM Li-ion cells,indicating its poor overcharge tolerance and high TR risk.However,when TR occurred,LFP Li-ion cell exhibited lower maximum temperature and mild TR response.All NCM Liion cells caught fire or exploded during TR,while the LFP Li-ion cell only released a large amount of smoke without fire.According to the overcharge behaviors and TR features,a safety assessment score system was proposed to evaluate the safety of the cells.In short,NCM Li-ion cells have better performance in energy density and overcharge tolerance(or low TR risk),while LFP Li-ion cell showed less severe response to overcharging(or less TR hazards).For NCM Li-ion cells,as the ratio of nickel in cathode material increases,the thermal stability of the cathode materials becomes poorer,and the TR hazards increase.Such a comparison study on large format Li-ion cells with different cathode materials can provide deeper insights into the overcharge behaviors and TR features,and provide guidance for engineers to reasonably choose battery materials in automotive applications.展开更多
In maritime safety research,risk is assessed usually within the framework of formal safety assessment(FSA),which provides a formal and systematic methodology to improve the safety of lives,assets,and the environment.A...In maritime safety research,risk is assessed usually within the framework of formal safety assessment(FSA),which provides a formal and systematic methodology to improve the safety of lives,assets,and the environment.A bespoke application of FSA to mitigate accidents in marine seismic surveying is put forward in this paper,with the aim of improving the safety of seismic vessel operations,within the context of developing an economically viable strategy.The work herein takes a close look at the hazards in North Sea offshore seismic surveying,in order to identify critical risk factors,leading to marine seismic survey accidents.The risk factors leading to undesirable events are analysed both qualitatively and quantitatively.A risk matrix is introduced to screen the identified undesirable events.Further to the screening,Fault Tree Analysis(FTA)is presented to investigate and analyse the most critical risks of seismic survey operation,taking into account the lack of historical data.The obtained results show that man overboard(MOB)event is a major risk factor in marine seismic survey operation;lack of training on safe work practice,slippery deck as a result of rain,snow or water splash,sea state affecting human judgement,and poor communication are identified as the critical risk contributors to the MOB event.Consequently,the risk control options are focused on the critical risk contributors for decision-making.Lastly,suggestions for the introduction and development of the FSA methodology are highlighted for safer marine and offshore operations in general.展开更多
Autonomous aerial refueling(AAR)has demonstrated significant benefits to aviation by extending the aircraft range and endurance.It is of significance to assess system safety for autonomous aerial refueling.In this pap...Autonomous aerial refueling(AAR)has demonstrated significant benefits to aviation by extending the aircraft range and endurance.It is of significance to assess system safety for autonomous aerial refueling.In this paper,the reachability analysis method is adopted to assess system safety.Due to system uncertainties,the aerial refueling system can be considered as a stochastic system.Thus,probabilistic reachability is considered.Since there is a close relationship between reachability probability and collision probability,the collision probability of the AAR system is analyzed by using reachability analysis techniques.Then,the collision probability is accessed by using the Monte-Carlo experiment method.Finally,simulations demonstrate the effectiveness of the proposed safety assessment method.展开更多
Although monosodium glutamate(MSG)is a widely used food additive,its safety and systemic side effects have not been fully clarified.The intestinal flora is closely associated with human health;however,it remains uncle...Although monosodium glutamate(MSG)is a widely used food additive,its safety and systemic side effects have not been fully clarified.The intestinal flora is closely associated with human health;however,it remains unclear whether MSG consumption can affect health by acting on the intestinal flora.In this study,serum biomarkers,intestinal structure,intestinal immunity,and intestinal flora were examined to investigate the effects of different doses of sodium glutamate on the body,intestinal function,and intestinal flora of mice.The results showed that 30 mg/kg MSG had no significant effect on serum C-reactive protein,trimethylamine N-oxide,angiotensin II,intestinal interleukin(IL)-1β,IL-6,tumor necrosis factor-α,secretory IgA and fecal albumin in mice,but also promoted intestinal development and regulated the intestinal flora.Moreover,1500 mg/kg MSG increased the risk of cardiovascular disease and damaged the intestinal structure and flora.In this study,MSG was also found to be healthier than salt at the equivalent sodium concentration.Collectively,these findings suggested that low doses of MSG were safe for mice and may have some health benefits as a probiotic by promoting intestinal development and regulating the intestinal flora.展开更多
Coal mine safety is a complex system, which is controlled by a number of interrelated factors and is difficult to estimate. This paper proposes an index system of safety assessment based on correlated factors involved...Coal mine safety is a complex system, which is controlled by a number of interrelated factors and is difficult to estimate. This paper proposes an index system of safety assessment based on correlated factors involved in coal mining and a comprehensive evaluation model that combines the advantages of the AHP and a grey clustering method to guarantee the accuracy and objectivity of weight coefficients. First, we confirmed the weight of every index using the AHP, then did a general safety assessment by means of a grey clustering method. This model analyses the status of mining safety both qualitatively and quantitatively. It keeps management and technical groups informed of the situation of the coal production line in real time, which aids in making correct decisions based on practical safety issues. A case study in the application of the model is presented. The results show that the method is applicable and realistic with regard to the core of a coal mine's safety management. Consequently, the safe production of a mine and the awareness of advanced safe production management is accelerated.展开更多
Human normal flora is a source of probiotics.The safety characteristics of a specific isolate determine its application in foods or drugs.The food-borne-pathogen antagonist strain Lactobacillus gasseri HMV18 is one of...Human normal flora is a source of probiotics.The safety characteristics of a specific isolate determine its application in foods or drugs.The food-borne-pathogen antagonist strain Lactobacillus gasseri HMV18 is one of the isolates from normal human flora.In this work,we assessed the in vitro pH tolerance,bile tolerance,biogenic amine production,mucin utilization,and safety of in vivo administration to mice to evaluate general health,organ-body weight index,organ histopathological change,whether L.gasseri HMV18 can colonize in the gut or modulate the gut microbiota after oral administration.The results suggest that L.gasseri HMV18 can tolerate pH 3 for 2 h,3%bile for 3 h,biogenic amine negative,mucin usage negative,does not encode verified toxins,and cause no visible change in mice's organs.L.gasseri HMV18 might not colonize in mice's gut,but can significantly affect the structure of gut microbiota.A bibliographical survey suggested that there were as few as 8 opportunistic infection cases from 1984 to 2022 and that the possibility for L.gasseri to cause infection is relatively low.Therefore,this work provides a basis for the foods or drugs application of L.gasseri HMV18 and gives a map of experiments for the safety assessment of probiotics.展开更多
Quantified risk assessment(QRA) needs mathematicization of risk theory.However,attention has been paid almost exclusively to applications of assessment methods,which has led to neglect of research into fundamental the...Quantified risk assessment(QRA) needs mathematicization of risk theory.However,attention has been paid almost exclusively to applications of assessment methods,which has led to neglect of research into fundamental theories,such as the relationships among risk,safety,danger,and so on.In order to solve this problem,as a first step,fundamental theoretical relationships about risk and risk management were analyzed for this paper in the light of mathematics,and then illustrated with some charts.Second,man-machine-environment-management(MMEM) theory was introduced into risk theory to analyze some properties of risk.On the basis of this,a three-dimensional model of risk management was established that includes:a goal dimension;a management dimension;an operation dimension.This goal management operation(GMO) model was explained and then emphasis was laid on the discussion of the risk flowchart(operation dimension),which lays the groundwork for further study of risk management and qualitative and quantitative assessment.Next,the relationship between Formal Safety Assessment(FSA) and Risk Management was researched.This revealed that the FSA method,which the international maritime organization(IMO) is actively spreading,comes from Risk Management theory.Finally,conclusion were made about how to apply this risk management method to concrete fields efficiently and conveniently,as well as areas where further research is required.展开更多
This paper discusses some issues on human reliability model of time dependent human behavior. Some results of the crew reliability experiment on Tsinghua training simulator in China are given, Meanwhile, a case of ca...This paper discusses some issues on human reliability model of time dependent human behavior. Some results of the crew reliability experiment on Tsinghua training simulator in China are given, Meanwhile, a case of calculation for human error probability during anticipated transient without scram (ATWS) based on the data drew from the recent experiment is offered.展开更多
Mutual influence may be driven by different models and operating mechanisms of grounding systems in multi-in-one substations.Even equipment damage and personal injury will occur in the event of a short-circuit or ligh...Mutual influence may be driven by different models and operating mechanisms of grounding systems in multi-in-one substations.Even equipment damage and personal injury will occur in the event of a short-circuit or lightning strike.To meet the construction requirements of different multi-in-one substations,two typical application modes of grounding systems in multi-in-one substations are analyzed in this paper:plane and longitudinal layout schemes.First,the safety index and withstand voltage of secondary equipment in multi-in-one substations are introduced.Second,the plane layout scheme of grounding grids is examined.Based on a 35-kV multi-in-one substations in Shanghai,it was verified that the overall grounding grid needs to be laid to meet the safety of secondary equipment in the station.Finally,considering that it is feasible to rebuild the upper layer of a substation,the longitudinal layout scheme of the grounding grid in multi-in-one substations is also examined.Safety assessment is carried out in terms of aspects such as short-circuits and lightning strikes,and relevant optimization construction methods are analyzed.In this study,a real 35-kV substation in Shanghai was selected as an example.Simulation and field tests based on Current Distribution,Electromagnetic Fields,Grounding and Soil Structure Analysis(CDEGS)software verified that the proposed construction scheme can achieve safe operation of multi-in-one substations.This construction idea can also serve as a reference for the future construction of multi-in-one substations.展开更多
The applications of risk index to risk estimation, risk acceptability, and cost-benefit analysis for planning vessel traffic service （VTS） system were analyzed. An example of Wuhan Port shows that its application is...The applications of risk index to risk estimation, risk acceptability, and cost-benefit analysis for planning vessel traffic service （VTS） system were analyzed. An example of Wuhan Port shows that its application is easily implemented and can be helpful in a comprcbensive and scientific decision-making. Especially aiming to the difficult problems with respect to risk prediction, risk acceptability and cost-benefit assessment, this article put forward some new solutions based on risk-index, such as the trendline estimation, ALARP （as low as reasonably practicable） matrix and weighted cost-benefit analysis, with a fairly good operability and comparability.展开更多
Cascading thermal runaway(TR)propagation poses a critical safety concern for large-format sodium-ion battery(SIB)systems because of the heightened risks of fires or explosions.However,effectively suppressing TR propag...Cascading thermal runaway(TR)propagation poses a critical safety concern for large-format sodium-ion battery(SIB)systems because of the heightened risks of fires or explosions.However,effectively suppressing TR propagation without introducing unintended side effects remains a significant challenge.Herein,we demonstrate a localized energy release method to mitigate TR,by reducing the state of charge(SOC)of cells adjacent to the thermally runaway unit.We discover that as the SOCs decreased from 100%to 25%,the TR trigger temperature decreased significantly,and the maximum temperature decrease from 367 to 229℃.Meanwhile,the volume of gas decreased to one-third of its original value,while the range of explosion limits significantly narrowed.The analysis of the morphology of the debris further confirms that the structural damage is greater at higher SOC levels.Moreover,an Entropy Weight and Technique for Order Preference by Similarity to an Ideal Solution(EW-TOPSIS)method has been established to assess the safety status of SIBs,showing that the TR possibility is nearly linear with the SOCs,and the TR hazard is exponentially related to the SOCs.Finally,when the SOC of cells adjacent to the TR cell is reduced to 25%,TR can be directly blocked without the need for additional cooling or thermal insulation methods.This study not only advances the understanding of TR behavior in SIBs but also offers a straightforward approach to mitigating the TR risk in SIB systems.展开更多
基金This research was supported by the Funding Project of Chinese Central Government Guiding to the Guangxi Local Science and Technology Development(GUIKEZY21195021)the Natural Science Fund for Distinguished Young Scholars of Guangxi Zhuang Autonomous Region of China(2019GXNSFFA245011)+3 种基金the Funding Project of Chinese Central Government Guiding to the Nanning Local Science and Technology Development(20231012)the Funding Projects of Guangxi Key Research and Development Plan(GUIKE AB23075173)the Funding Project of Technological Development from Angel Yeast(Chongzuo)Co.,Ltd.(JS1006020230722019)the Innovation Project of Guangxi Graduate Education(YCBZ2021012).
文摘The application of microorganisms as probiotics is limited due to lack of safety evaluation.Here,a novel multi-stress-tolerant yeast Meyerozyma guilliermondii GXDK6 with aroma-producing properties was identified from marine mangrove microorganisms.Its safety and probiotic properties were assessed in accordance with phenotype and whole-genome sequencing analysis.Results showed that the genes and phenotypic expression of related virulence,antibiotic resistance and retroelement were rarely found.Hyphal morphogenesis genes(SIT4,HOG1,SPA2,ERK1,ICL1,CST20,HSP104,TPS1,and RHO1)and phospholipase secretion gene(VPS4)were annotated.True hyphae and phospholipase were absent.Only one retroelement(Tad1-65_BG)was found.Major biogenic amines(BAs)encoding genes were absent,except for spermidine synthase(JA9_002594),spermine synthase(JA9_004690),and tyrosine decarboxylase(inx).The production of single BAs and total BAs was far below the food-defined thresholds.GXDK6 had no resistance to common antifungal drugs.Virulence enzymes,such as gelatinase,DNase,hemolytic,lecithinase,and thrombin were absent.Acute toxicity test with mice demonstrated that GXDK6 is safe.GXDK6 has a good reproduction ability in the simulation gastrointestinal tract.GXDK6 also has a strong antioxidant ability,β-glucosidase,and inulinase activity.To sum up,GXDK6 is considered as a safe probiotic for human consumption and food fermentation.
基金Supported by the National High Technology Research and Development Program of China("863"Program)(2006AA12A105)~~
文摘A new safety assessment method for parallel routes is presented. From the aspects of safety guard system of air traffic control（ATC） and considering the flight conflict as causing event of air collision accidents, this paper fosters a four-layer safety guard of controller command, short-term conflict alerts （STCAs）, pilot visual avoidance, and traffic alert collision avoidance system（TCAS）. Then, the problem of parallel routes collision risk is divided into two parts：the calculation of potential flight conflict and the analysis of failure probability of the four-layer safety guard. A calculation model for controller interference times is induced. By using cognitive reliability and error analysis method（CREAM）,the calculation problem to failure probability of controller sequencing flight conflicts is solved and a fault tree model of guard failure of STCA and TCAS is established. Finally, the Beijing-Shanghai parallel routes are taken as an example to be calculated and the collision risk of the parallel routes is obtained under the condition of radar control. Results show that the parallel routes can satisfy the safety demands.
基金supported by the National Natural Science Foundation of China(Nos.U1564206,U1764258)the National Key R&D Program of China(No.2018YFB0105700)+1 种基金the support from China Scholarship Council(No.201806030115)supported by the Department of Energy(DOE),Office of Electricity(OE)at Oak Ridge National Laboratory managed by UL-Battelle LLC under contract DE-AC05-00OR22725。
文摘In this paper,overcharge behaviors and thermal runaway(TR)features of large format lithium-ion(Liion)cells with different cathode materials(LiFePO4(LFP),Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_(2)(NCM111),Li[Ni_(0.6)Co_(0.2)Mn_(0.2)]O_(2)(NCM622)and Li[Ni_(0.8)Co_(0.1)Mn_(0.1)]O_(2)(NCM811))were investigated.The results showed that,under the same overcharge condition,the TR of LFP Li-ion cell occurred earlier compared with the NCM Li-ion cells,indicating its poor overcharge tolerance and high TR risk.However,when TR occurred,LFP Li-ion cell exhibited lower maximum temperature and mild TR response.All NCM Liion cells caught fire or exploded during TR,while the LFP Li-ion cell only released a large amount of smoke without fire.According to the overcharge behaviors and TR features,a safety assessment score system was proposed to evaluate the safety of the cells.In short,NCM Li-ion cells have better performance in energy density and overcharge tolerance(or low TR risk),while LFP Li-ion cell showed less severe response to overcharging(or less TR hazards).For NCM Li-ion cells,as the ratio of nickel in cathode material increases,the thermal stability of the cathode materials becomes poorer,and the TR hazards increase.Such a comparison study on large format Li-ion cells with different cathode materials can provide deeper insights into the overcharge behaviors and TR features,and provide guidance for engineers to reasonably choose battery materials in automotive applications.
基金This project"Formal Safety Assessment of a Marine Seismic Survey Vessel Operation,Incorporating Risk Matrix and Fault Tree Analysis"has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 730888.
文摘In maritime safety research,risk is assessed usually within the framework of formal safety assessment(FSA),which provides a formal and systematic methodology to improve the safety of lives,assets,and the environment.A bespoke application of FSA to mitigate accidents in marine seismic surveying is put forward in this paper,with the aim of improving the safety of seismic vessel operations,within the context of developing an economically viable strategy.The work herein takes a close look at the hazards in North Sea offshore seismic surveying,in order to identify critical risk factors,leading to marine seismic survey accidents.The risk factors leading to undesirable events are analysed both qualitatively and quantitatively.A risk matrix is introduced to screen the identified undesirable events.Further to the screening,Fault Tree Analysis(FTA)is presented to investigate and analyse the most critical risks of seismic survey operation,taking into account the lack of historical data.The obtained results show that man overboard(MOB)event is a major risk factor in marine seismic survey operation;lack of training on safe work practice,slippery deck as a result of rain,snow or water splash,sea state affecting human judgement,and poor communication are identified as the critical risk contributors to the MOB event.Consequently,the risk control options are focused on the critical risk contributors for decision-making.Lastly,suggestions for the introduction and development of the FSA methodology are highlighted for safer marine and offshore operations in general.
基金This work was supported by the National Natural Science Foundation of China(No.61933010).
文摘Autonomous aerial refueling(AAR)has demonstrated significant benefits to aviation by extending the aircraft range and endurance.It is of significance to assess system safety for autonomous aerial refueling.In this paper,the reachability analysis method is adopted to assess system safety.Due to system uncertainties,the aerial refueling system can be considered as a stochastic system.Thus,probabilistic reachability is considered.Since there is a close relationship between reachability probability and collision probability,the collision probability of the AAR system is analyzed by using reachability analysis techniques.Then,the collision probability is accessed by using the Monte-Carlo experiment method.Finally,simulations demonstrate the effectiveness of the proposed safety assessment method.
基金supported by the Inner Mongolia Autonomous Region Science and Technology Achievement Transformation Project(CGZH2018035).
文摘Although monosodium glutamate(MSG)is a widely used food additive,its safety and systemic side effects have not been fully clarified.The intestinal flora is closely associated with human health;however,it remains unclear whether MSG consumption can affect health by acting on the intestinal flora.In this study,serum biomarkers,intestinal structure,intestinal immunity,and intestinal flora were examined to investigate the effects of different doses of sodium glutamate on the body,intestinal function,and intestinal flora of mice.The results showed that 30 mg/kg MSG had no significant effect on serum C-reactive protein,trimethylamine N-oxide,angiotensin II,intestinal interleukin(IL)-1β,IL-6,tumor necrosis factor-α,secretory IgA and fecal albumin in mice,but also promoted intestinal development and regulated the intestinal flora.Moreover,1500 mg/kg MSG increased the risk of cardiovascular disease and damaged the intestinal structure and flora.In this study,MSG was also found to be healthier than salt at the equivalent sodium concentration.Collectively,these findings suggested that low doses of MSG were safe for mice and may have some health benefits as a probiotic by promoting intestinal development and regulating the intestinal flora.
文摘Coal mine safety is a complex system, which is controlled by a number of interrelated factors and is difficult to estimate. This paper proposes an index system of safety assessment based on correlated factors involved in coal mining and a comprehensive evaluation model that combines the advantages of the AHP and a grey clustering method to guarantee the accuracy and objectivity of weight coefficients. First, we confirmed the weight of every index using the AHP, then did a general safety assessment by means of a grey clustering method. This model analyses the status of mining safety both qualitatively and quantitatively. It keeps management and technical groups informed of the situation of the coal production line in real time, which aids in making correct decisions based on practical safety issues. A case study in the application of the model is presented. The results show that the method is applicable and realistic with regard to the core of a coal mine's safety management. Consequently, the safe production of a mine and the awareness of advanced safe production management is accelerated.
基金financially supported by postdoctoral funding of Hebei Medical UniversityHebei Province Postdoctoral Research Project Funding(B2022003035)+5 种基金Natural Science Foundation of Hebei Province(H2020206579)CAMS Innovation Found for Medical Sciences(2019-I2M-5-055)2023 Scientific Research Projects of Colleges and Universities in Hebei Province(QN2023131)S&T Program of Hebei(18277743D)Undergraduate Innovation Experiment Project from Hebei Medical University(USIP2019008)Spring rain project of Hebei Medical University(CYCZ201906)。
文摘Human normal flora is a source of probiotics.The safety characteristics of a specific isolate determine its application in foods or drugs.The food-borne-pathogen antagonist strain Lactobacillus gasseri HMV18 is one of the isolates from normal human flora.In this work,we assessed the in vitro pH tolerance,bile tolerance,biogenic amine production,mucin utilization,and safety of in vivo administration to mice to evaluate general health,organ-body weight index,organ histopathological change,whether L.gasseri HMV18 can colonize in the gut or modulate the gut microbiota after oral administration.The results suggest that L.gasseri HMV18 can tolerate pH 3 for 2 h,3%bile for 3 h,biogenic amine negative,mucin usage negative,does not encode verified toxins,and cause no visible change in mice's organs.L.gasseri HMV18 might not colonize in mice's gut,but can significantly affect the structure of gut microbiota.A bibliographical survey suggested that there were as few as 8 opportunistic infection cases from 1984 to 2022 and that the possibility for L.gasseri to cause infection is relatively low.Therefore,this work provides a basis for the foods or drugs application of L.gasseri HMV18 and gives a map of experiments for the safety assessment of probiotics.
基金Supported by the Shanghai Leading Academic Discipline Project Foundation under Grant No.T0602Supported by the Shanghai Education Commission Project Foundation under Grant No.05FZ10
文摘Quantified risk assessment(QRA) needs mathematicization of risk theory.However,attention has been paid almost exclusively to applications of assessment methods,which has led to neglect of research into fundamental theories,such as the relationships among risk,safety,danger,and so on.In order to solve this problem,as a first step,fundamental theoretical relationships about risk and risk management were analyzed for this paper in the light of mathematics,and then illustrated with some charts.Second,man-machine-environment-management(MMEM) theory was introduced into risk theory to analyze some properties of risk.On the basis of this,a three-dimensional model of risk management was established that includes:a goal dimension;a management dimension;an operation dimension.This goal management operation(GMO) model was explained and then emphasis was laid on the discussion of the risk flowchart(operation dimension),which lays the groundwork for further study of risk management and qualitative and quantitative assessment.Next,the relationship between Formal Safety Assessment(FSA) and Risk Management was researched.This revealed that the FSA method,which the international maritime organization(IMO) is actively spreading,comes from Risk Management theory.Finally,conclusion were made about how to apply this risk management method to concrete fields efficiently and conveniently,as well as areas where further research is required.
文摘This paper discusses some issues on human reliability model of time dependent human behavior. Some results of the crew reliability experiment on Tsinghua training simulator in China are given, Meanwhile, a case of calculation for human error probability during anticipated transient without scram (ATWS) based on the data drew from the recent experiment is offered.
基金supported by National Natural Science Foundation of China(No.92067105)the science and technology project of State Grid Shanghai Municipal Electric Power Company(No.5209211900VD).
文摘Mutual influence may be driven by different models and operating mechanisms of grounding systems in multi-in-one substations.Even equipment damage and personal injury will occur in the event of a short-circuit or lightning strike.To meet the construction requirements of different multi-in-one substations,two typical application modes of grounding systems in multi-in-one substations are analyzed in this paper:plane and longitudinal layout schemes.First,the safety index and withstand voltage of secondary equipment in multi-in-one substations are introduced.Second,the plane layout scheme of grounding grids is examined.Based on a 35-kV multi-in-one substations in Shanghai,it was verified that the overall grounding grid needs to be laid to meet the safety of secondary equipment in the station.Finally,considering that it is feasible to rebuild the upper layer of a substation,the longitudinal layout scheme of the grounding grid in multi-in-one substations is also examined.Safety assessment is carried out in terms of aspects such as short-circuits and lightning strikes,and relevant optimization construction methods are analyzed.In this study,a real 35-kV substation in Shanghai was selected as an example.Simulation and field tests based on Current Distribution,Electromagnetic Fields,Grounding and Soil Structure Analysis(CDEGS)software verified that the proposed construction scheme can achieve safe operation of multi-in-one substations.This construction idea can also serve as a reference for the future construction of multi-in-one substations.
基金The project of Shanghai Science andTechnology Committee (No.052112060)
文摘The applications of risk index to risk estimation, risk acceptability, and cost-benefit analysis for planning vessel traffic service （VTS） system were analyzed. An example of Wuhan Port shows that its application is easily implemented and can be helpful in a comprcbensive and scientific decision-making. Especially aiming to the difficult problems with respect to risk prediction, risk acceptability and cost-benefit assessment, this article put forward some new solutions based on risk-index, such as the trendline estimation, ALARP （as low as reasonably practicable） matrix and weighted cost-benefit analysis, with a fairly good operability and comparability.
基金supported by the National Key R&D Program of China(2023YFB2407900)the National Natural Science Foundation of China(52302512)+1 种基金State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(KFZD202305)Zhejiang Province Science and Technology Program Grant(2024C0127(SD2))。
文摘Cascading thermal runaway(TR)propagation poses a critical safety concern for large-format sodium-ion battery(SIB)systems because of the heightened risks of fires or explosions.However,effectively suppressing TR propagation without introducing unintended side effects remains a significant challenge.Herein,we demonstrate a localized energy release method to mitigate TR,by reducing the state of charge(SOC)of cells adjacent to the thermally runaway unit.We discover that as the SOCs decreased from 100%to 25%,the TR trigger temperature decreased significantly,and the maximum temperature decrease from 367 to 229℃.Meanwhile,the volume of gas decreased to one-third of its original value,while the range of explosion limits significantly narrowed.The analysis of the morphology of the debris further confirms that the structural damage is greater at higher SOC levels.Moreover,an Entropy Weight and Technique for Order Preference by Similarity to an Ideal Solution(EW-TOPSIS)method has been established to assess the safety status of SIBs,showing that the TR possibility is nearly linear with the SOCs,and the TR hazard is exponentially related to the SOCs.Finally,when the SOC of cells adjacent to the TR cell is reduced to 25%,TR can be directly blocked without the need for additional cooling or thermal insulation methods.This study not only advances the understanding of TR behavior in SIBs but also offers a straightforward approach to mitigating the TR risk in SIB systems.
