BACKGROUND Acute respiratory distress syndrome(ARDS)is a critical condition characterized by acute hypoxemia,non-cardiogenic pulmonary edema,and decreased lung compliance.The Berlin definition,updated in 2012,classifi...BACKGROUND Acute respiratory distress syndrome(ARDS)is a critical condition characterized by acute hypoxemia,non-cardiogenic pulmonary edema,and decreased lung compliance.The Berlin definition,updated in 2012,classifies ARDS severity based on the partial pressure of arterial oxygen/fractional inspired oxygen fraction ratio.Despite various treatment strategies,ARDS remains a significant public health concern with high mortality rates.AIM To evaluate the implications of driving pressure(DP)in ARDS management and its potential as a protective lung strategy.METHODS We conducted a systematic review using databases including EbscoHost,MEDLINE,CINAHL,PubMed,and Google Scholar.The search was limited to articles published between January 2015 and September 2024.Twenty-three peer-reviewed articles were selected based on inclusion criteria focusing on adult ARDS patients undergoing mechanical ventilation and DP strategies.The literature review was conducted and reported according to PRISMA 2020 guidelines.RESULTS DP,the difference between plateau pressure and positive end-expiratory pressure,is crucial in ARDS management.Studies indicate that lower DP levels are significantly associated with improved survival rates in ARDS patients.DP is a better predictor of mortality than tidal volume or positive end-expiratory pressure alone.Adjusting DP by optimizing lung compliance and minimizing overdistension and collapse can reduce ventilator-induced lung injury.CONCLUSION DP is a valuable parameter in ARDS management,offering a more precise measure of lung stress and strain than traditional metrics.Implementing DP as a threshold for safety can enhance protective ventilation strategies,po-tentially reducing mortality in ARDS patients.Further research is needed to refine DP measurement techniques and validate its clinical application in diverse patient populations.展开更多
BACKGROUND Prolonged immobility during intensive care unit(ICU)admission has been a cause of muscle atrophy and worsening functional outcomes with longer recovery times.Prior research has demonstrated that mobilizatio...BACKGROUND Prolonged immobility during intensive care unit(ICU)admission has been a cause of muscle atrophy and worsening functional outcomes with longer recovery times.Prior research has demonstrated that mobilization within a week of ICU admission potentially benefits physical function in critically ill patients.AIM To evaluate the effects of initiating mobilization within 72 hours of ICU admission in critically ill patients through an updated systematic review and meta-analysis.METHODS A systematic search was performed through MEDLINE,Scopus,and Cochrane Library from inception until September 2024 for randomized controlled trials(RCTs)comparing early mobilization(EM)with usual or conventional care in critically ill adult patients.Primary outcomes included length of ICU(days)and ventilation duration(days).Secondary outcomes included muscle strength,functional status,adverse events,all-cause mortality,and quality of life(QOL).A random effects meta-analysis was performed for pooled effect estimates and to derive risk ratios(RR)and corresponding 95%confidence intervals(CI).RESULTS Out of 3487 results,16 RCTs were included with a population of 2385 patients(1195 receiving EM and 1190 with usual care.)A significant reduction in the length of ICU stays[mean difference(MD)=-1.02,95%CI:-1.96 to-0.09;P=0.03;I2=60%]and ventilation duration(MD=-1.07,95%CI:-1.91 to-0.23,P=0.01;I2=57%)was observed in the EM group compared to usual care.EM significantly improved muscle strength[standard MD(SMD)=0.47,95%CI:0.18-0.75,P=0.001;I2=79%]and functional status(SMD=0.70,95%CI:0.40-1.00,P<0.00001;I2=81%)in ICU patients.No statistically significant difference was observed in adverse events(RR=1.72,95%CI:1.01-2.94,P=0.05;I2=31%),all-cause mortality(RR=1.10,95%CI:0.79-1.53,P=0.57;I2=30%),and QOL(SMD=0.04,95%CI:-0.07-0.15,P=0.50;I2=9%)between the two groups.CONCLUSION Initiating mobilization within 72 hours of ICU admission is associated with improved functional outcomes and reduced ICU length of stay and ventilation duration.These findings indicate that EM may be a safe option for ICU patients,contributing to lower recovery times and healthcare costs.Further extensive research is required to validate the long-term effects on survival and QOL.展开更多
This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilizat...This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilization, and precipitation adjustment.The rainwater collection system in this program also adds the condensation water from the heating, ventilation and air conditioning （ HVAC） system and the concentration from the reverse-osmosis system used for watering greens and supplying waterscapes.By calculating, the quantity of the HVAC condensation water in summer is 3.48 m3/d, and the quantity of the reverse-osmosis concentrated water is 198 to 396 L/d.This method solves the water shortage caused by high evaporation in summer and low precipitation in winter.Supported by empirical monitoring data, the proposed method significantly increases the economic efficiency of the system during the summer period.展开更多
Severe acute pancreatitis(SAP)can induce acute respiratory distress syndrome(ARDS)and abdominal compartment syndrome(ACS).Although prone position ventilation(PPV)can improve outcomes in patients with ARDS,there is sig...Severe acute pancreatitis(SAP)can induce acute respiratory distress syndrome(ARDS)and abdominal compartment syndrome(ACS).Although prone position ventilation(PPV)can improve outcomes in patients with ARDS,there is significant controversy regarding its concurrent use with ACS owing to concerns of increased risk of intra-abdominal pressure(IAP).[1]We present a case of successful PPV application without adverse eff ects.展开更多
The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,...The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.展开更多
Objective:To investigate the application effect of intelligent empowerment standardized airway management process in patients receiving mechanical ventilation.Methods:A retrospective analysis was conducted on the clin...Objective:To investigate the application effect of intelligent empowerment standardized airway management process in patients receiving mechanical ventilation.Methods:A retrospective analysis was conducted on the clinical data of 79 EICU inpatients who underwent tracheal intubation and mechanical ventilation treatment at our hospital from January 2023 to May 2025.The patients were divided into a control group(conventional airway management process,n=40)and a study group(intelligent empowerment standardized airway management process,n=39)based on the intervention protocols they received.Oral health scores,dental plaque index,oral odor,serum inflammatory markers[C-reactive protein(CRP),procalcitonin(PCT)],clinical pulmonary infection score(CPIS),as well as the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were assessed before and after treatment.Results:The baseline values of all indicators were consistent between the two groups before intervention(p>0.05).After corresponding interventions,both groups showed significant improvements in Beck oral health scores,dental plaque index,and oral odor,with more pronounced improvements observed in the study group(p<0.05).After the intervention,the research group showed a significant decrease in serum CRP and PCT levels,as well as CPIS scores(p<0.05).In contrast,the control group experienced an increase in these three indicators to a certain extent(p<0.05).Moreover,the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were all lower in the research group compared to the control group,while the nurse’s compliance rate with the protocol was higher in the research group(p<0.05).Conclusion:The standardized airway management protocol empowered by intelligent technology can significantly improve nursing compliance,benefit oral health status,reduce the risk of pulmonary infection and systemic inflammation levels,and promote rapid patient recovery,demonstrating considerable potential for widespread adoption.展开更多
This study aims to mitigate crosswind-induced performance degradation in Natural Draft Dry Cooling Towers used in power plants by developing and assessing windbreak configurations that enhance ventilation while minimi...This study aims to mitigate crosswind-induced performance degradation in Natural Draft Dry Cooling Towers used in power plants by developing and assessing windbreak configurations that enhance ventilation while minimizing additional airflow resistance.Three novel windbreak designs,namely single-windbreak configuration with curved profile,double-windbreak configuration with curved profile,and double-windbreak configuration with inverted curved profile,are proposed accordingly and evaluated against conventional solutions.Three-dimensional numerical models of a 120 m high NDDCT equipped with these windbreaks,together with a conventional Y-shaped windbreak,are developed for systematic comparison.The results demonstrate that windbreak effectiveness strongly depends on crosswind intensity.At low crosswind speeds of 0-6 m/s,the Y-shaped windbreak provides the greatest enhancement,increasing the ventilation rate by 25.45%and the heat rejection rate by 21.37%at 6 m/s compared with the no-windbreak configuration.In contrast,under moderate to strong crosswinds of 6-18 m/s,the single-windbreak configuration with curved profile exhibits superior performance.At 18 m/s,it increases the ventilation rate by 148.88%and the heat rejection rate by 79.74%relative to the baseline case,outperforming the Y-shaped windbreak by 26.59%in ventilation rate and 17.01%in heat rejection capacity.Analysis of airflow structure,temperature fields,and velocity distributions confirms that the single-windbreak configuration with curved profile more effectively suppresses crosswind penetration and promotes stable upward airflow at higher wind speeds.Based on a comprehensive assessment of aerodynamic and thermal performance,the Y-shaped windbreak is recommended for regions where crosswind speeds remain below 6 m/s,whereas the single-windbreak configuration with curved profile is preferable for sites exposed to stronger crosswinds exceeding this threshold.展开更多
An automated underground mine monitoring and communication system based on the integration of new technologies is introduced to promote safety and health,operational management and cost-effectiveness.The proposed syst...An automated underground mine monitoring and communication system based on the integration of new technologies is introduced to promote safety and health,operational management and cost-effectiveness.The proposed system integration considering Wireless Sensor Network(WSN) assisted Geographic Information System(GIS) enables to monitor and control underground mining applications from surface office.Based on the capabilities of WSNs,ZigBee network is adapted for near real-time monitoring,ventilation system control and emergency communication in underground mine.ZigBee nodes were developed to sense environmental attributes such as temperature,humidity and gases concentration;switching ON and OFF ventilation fans;and texting emergency messages.A trigger action plan for monitored attributes above normal and threshold value limits is programmed in the surface GIS management server.It is designed to turn the auxiliary fans on remotely or automatically in orange condition and sending evacuation messages for underground miners in unsafe(red) condition.Multi-users operation and 3D visualisations are other successful achievements of the proposed system for the underground monitoring and communication.展开更多
The techniques of stress relief mining in low-permeability coal seams and pillarless gob side retained roadway entry using Y-type ventilation and gas drainage systems were developed to control gas outbursts and applie...The techniques of stress relief mining in low-permeability coal seams and pillarless gob side retained roadway entry using Y-type ventilation and gas drainage systems were developed to control gas outbursts and applied successfully. However, as the mining depth increasing, parts of the gas drainage system are not suitable for mines with high gas emissions. Because larger mining depths cause higher ground stresses, it becomes extremely difficult to maintain long gob side roadways. The greater deformation suffered by the roadway is not favorable lor borehole drilling for continuous gas drainage. To solve these problems, Y-type ventilation and gas drainage systems installed from a roof roadway were designed for drainage optimization. This system was designed based on a gas-enrichment zone analysis developed from mining the 11-2 coal seam in the Zhuji Mine at Huainan, Anhui Province, China. The method of Y-type gas extraction from different mine areas was applied to the panel 1112（1） in the Zhuji Mine. The absolute gas emission rate was up to 116.3 m^3/min with an average flow of 69.1 m^3/min at an average drainage concentration of nearly 85 %. After the Y-type method was adopted, the concentration of gas in the return air was 0.15 %-0.64 %, averaging 0.39 % with a ventilation rate of 2100-2750 m^3/min. The gas management system proved to be efficient, and the effective gas control allowed safe production to continue .展开更多
In order to reduce the probability of fault occurrence of local ventilation system in coal mine and prevent gas from exceeding the standard limit, an approach incorporating the reliability analysis, rough set theory, ...In order to reduce the probability of fault occurrence of local ventilation system in coal mine and prevent gas from exceeding the standard limit, an approach incorporating the reliability analysis, rough set theory, genetic algorithm (GA), and intelligent decision support system (IDSS) was used to establish and develop a fault diagnosis system of local ventilation in coal mine. Fault tree model was established and its reliability analysis was performed. The algorithms and software of key fault symptom and fault diagnosis rule acquiring were also analyzed and developed. Finally, a prototype system was developed and demonstrated by a mine instance. The research results indicate that the proposed approach in this paper can accurately and quickly find the fault reason in a local ventilation system of coal mines and can reduce difficulty of the fault diagnosis of the local ventilation system, which is significant to decrease gas exploding accidents in coal mines.展开更多
Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation sy...Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.展开更多
In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regre...In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regression method to analyze the effect, of changing the rules of mine airflows, on the stability of a mine ventilation system. The amount of air （ Qj ） is determined for the major airway and an optimum regression equation was derived for Qi as a function of the independent variable （ Ri ）, i.e., the venti- lation resistance between different airways. Therefore, corresponding countermeasures are proposed according to the changes in airflows. The calculated results agree very well with our practical situation, indicating that multiple regression analysis is simple, quick and practical and is therefore an effective method to analyze the stability of mine ventilation systems.展开更多
Diabetes affects approximately 30 million persons in the United States. Diabetes ketoacidosis is one of the most serious and acute complications of diabetes. At the time of presentation and during treatment of diabeti...Diabetes affects approximately 30 million persons in the United States. Diabetes ketoacidosis is one of the most serious and acute complications of diabetes. At the time of presentation and during treatment of diabetic ketoacidosis(DKA), several metabolic and electrolyte derangements can ultimately result in respiratory compromise. Most commonly, hypokalemia, hypomagnesemia and hypophosphatemia can eventually lead to respiratory muscles failure.Furthermore, tachypnea, hyperpnea and more severely, Kussmaul breathing pattern can develop. Also, hydrostatic and non-hydrostatic pulmonary edema can occur secondary to volume shifts into the extracellular space and secondary to increased permeability of the pulmonary capillaries. The presence of respiratory failure in patients with DKA is associated with higher morbidity and mortality. Being familiar with the causes of respiratory compromise in DKA, and how to treat them, may represent better outcomes for patients with DKA.展开更多
At high altitudes, an Aviation Oxygen Supply System （AOSS） protects pilots from low pressure and hypoxia by continuously providing oxygen corresponding to the pilots＇ dynamic respiratory properties. An AOSS mainly ...At high altitudes, an Aviation Oxygen Supply System （AOSS） protects pilots from low pressure and hypoxia by continuously providing oxygen corresponding to the pilots＇ dynamic respiratory properties. An AOSS mainly consists of oxygen supercharging machines which are used in a high-altitude flight cabin to supply pressurized oxygen to pilots. Therefore, it is of great significance to study the airflow dynamic characteristics of an AOSS for safe, continuous, and efficient oxygen supply. In this paper, an AOSS is firstly simplified and considered as a mechanical ventilation system. Then, its corresponding mathematical model is constructed. Next, to verify the mathematical model, a prototype AOSS with a lung simulator is proposed for an experimental study. Afterwards, to build a foundation for the optimization of the AOSS, the airflow dynamic characteristics of an aircraft are analyzed, and the effects of key parameters on the respiration system are researched. Through experimental and simulation studies, it can be concluded that the mathematical model is effective. Subsequently, for stability during the respiration process, we consider setting the equivalent throttling areas of the inspiration and expiration pipelines smaller within certain limits; additionally, an excessively high oxygen supply pressure will disturb smooth airflow, and in a low-pressure environment, the pressure can be 84 cmH20 lower than the standard atmospheric pressure. This research can be referred to in the design of an oxygen supply system and the study on optimization of airflow dynamic characteristics.展开更多
The underfloor air distribution(UFAD)system has not been able to penetrate the residential and commercial air conditioning industry significantly until now.To date,the most notable applications are found in datacenter...The underfloor air distribution(UFAD)system has not been able to penetrate the residential and commercial air conditioning industry significantly until now.To date,the most notable applications are found in datacenters because of their more demanding thermal stratification and cooling requirements.In addition to highlighting the advantages of the UFAD system over the traditional overhead(OH)system,this study compares various ventilation layouts for a UFAD system.Four different UFAD ventilation layouts are compared and one OH layout.The results show that using multiple swirl-type diffusers creates a more uniform floor-to-knee temperature and less air recirculation than the rectangular grille-type diffusers.Placing the return vents on the sides of the room creates a cooler environment by isolating recirculating air to a smaller space.At the end of the study,a design guide matrix is presented to summarize how the supply and return vent layout affects air conditioning performance.展开更多
A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a min...A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a mine, operators need to know the cause and effect of any changes requested from the VOD system. The sensitivity analysis is developed through generating a cause and effect matrix of sensitivity factors on given parameter changes in a ventilation system. This new utility, which was incorporated in the 3D-CANVENT mine ventilation simulator, is able to predict the airflow distributions in a ventilation network when underground conditions and ventilation controls are changed. For a primary ventilation system, the software can determine the optimal operating speed of the main fans to satisfy the airflow requirements in underground workings without necessarily using booster fans and regulators locally. An optimized fan operating speed time-table would assure variable demand-based fresh air delivery to the production areas effectively, while generating significant savings in energy consumption and operating cost.展开更多
This study conducts an evaluation of air quality,dispersion of airborne expiratory pollutants and thermal comfort in aircraft cabin mini-environments using a critical examination of significant studies conducted over ...This study conducts an evaluation of air quality,dispersion of airborne expiratory pollutants and thermal comfort in aircraft cabin mini-environments using a critical examination of significant studies conducted over the last20 years.The research methods employed in these studies are also explained in detail.Based on the current literature,standard procedures for airplane personal ventilation and air quality investigations are defined for each study approach.Present study gaps are examined,and prospective study subjects for various research approaches are suggested.展开更多
Diesel particulate matter （DPM） is considered to be carcinogenic after prolonged exposure. With more diesel- powered equipment used in underground mines, miners＇ exposure to DPM has become an increasing concern. Th...Diesel particulate matter （DPM） is considered to be carcinogenic after prolonged exposure. With more diesel- powered equipment used in underground mines, miners＇ exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include： long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.展开更多
With depletion of shallow deposits,the number of underground mines expected to reach more than 3 km depth during their lifetime is growing.Although surface cooling plants are mostly effective in mine airconditioning,u...With depletion of shallow deposits,the number of underground mines expected to reach more than 3 km depth during their lifetime is growing.Although surface cooling plants are mostly effective in mine airconditioning,usually secondary cooling units are needed below 2 kmdepth.This need emerges due to the elevated thermal impacts caused by auto-compression of mine air as well as heat emissions from strata and mine machinery.As a result,in cold climates,like Canada,ultra-deep mines need their secondary underground cooling plants running year-round while the intake air must be heated to protect the sensitive machinery and liners from freezing during the winter season.To cool mine air,horizontal bulk-airconditioners with direct spray cooling systems are commonly used due to their high performance.Conventionally,sprayed water in bulk-air-coolers are mechanically circulated and refrigerated in coupled refrigeration plants.This set up can be transformed to a natural cooling/heating process by resurfacing the warm underground bulk-air-cooler spray water for mine air heating on the surface and re-sinking the chilled water for cooling in the underground bulk air coolers.This could significantly cut-down the fossil-fuel consumption in burners for mine air pre-conditioning and refrigeration cost when applicable.This paper presents an anonymous real-life example to study the feasibility of the proposed idea for an ultra-deep Canadian mine.展开更多
Based on the basic content of advanced technology,safety and reliability, and economic reasonability and the definition of mine ventilation system, 16 assessment indexes of ventilation system are put forward from the ...Based on the basic content of advanced technology,safety and reliability, and economic reasonability and the definition of mine ventilation system, 16 assessment indexes of ventilation system are put forward from the point of 8 aspects such as mine ventilation power, ventilation network, ventilation equipments, ventilation quality, ventilation monitoring, capacity of preventing and fighting disaster, ventilation consumption of power, and the capacity of ventila- tion system. A new assessment index system is put forward and has a good effect after being applied in coal mines.展开更多
文摘BACKGROUND Acute respiratory distress syndrome(ARDS)is a critical condition characterized by acute hypoxemia,non-cardiogenic pulmonary edema,and decreased lung compliance.The Berlin definition,updated in 2012,classifies ARDS severity based on the partial pressure of arterial oxygen/fractional inspired oxygen fraction ratio.Despite various treatment strategies,ARDS remains a significant public health concern with high mortality rates.AIM To evaluate the implications of driving pressure(DP)in ARDS management and its potential as a protective lung strategy.METHODS We conducted a systematic review using databases including EbscoHost,MEDLINE,CINAHL,PubMed,and Google Scholar.The search was limited to articles published between January 2015 and September 2024.Twenty-three peer-reviewed articles were selected based on inclusion criteria focusing on adult ARDS patients undergoing mechanical ventilation and DP strategies.The literature review was conducted and reported according to PRISMA 2020 guidelines.RESULTS DP,the difference between plateau pressure and positive end-expiratory pressure,is crucial in ARDS management.Studies indicate that lower DP levels are significantly associated with improved survival rates in ARDS patients.DP is a better predictor of mortality than tidal volume or positive end-expiratory pressure alone.Adjusting DP by optimizing lung compliance and minimizing overdistension and collapse can reduce ventilator-induced lung injury.CONCLUSION DP is a valuable parameter in ARDS management,offering a more precise measure of lung stress and strain than traditional metrics.Implementing DP as a threshold for safety can enhance protective ventilation strategies,po-tentially reducing mortality in ARDS patients.Further research is needed to refine DP measurement techniques and validate its clinical application in diverse patient populations.
文摘BACKGROUND Prolonged immobility during intensive care unit(ICU)admission has been a cause of muscle atrophy and worsening functional outcomes with longer recovery times.Prior research has demonstrated that mobilization within a week of ICU admission potentially benefits physical function in critically ill patients.AIM To evaluate the effects of initiating mobilization within 72 hours of ICU admission in critically ill patients through an updated systematic review and meta-analysis.METHODS A systematic search was performed through MEDLINE,Scopus,and Cochrane Library from inception until September 2024 for randomized controlled trials(RCTs)comparing early mobilization(EM)with usual or conventional care in critically ill adult patients.Primary outcomes included length of ICU(days)and ventilation duration(days).Secondary outcomes included muscle strength,functional status,adverse events,all-cause mortality,and quality of life(QOL).A random effects meta-analysis was performed for pooled effect estimates and to derive risk ratios(RR)and corresponding 95%confidence intervals(CI).RESULTS Out of 3487 results,16 RCTs were included with a population of 2385 patients(1195 receiving EM and 1190 with usual care.)A significant reduction in the length of ICU stays[mean difference(MD)=-1.02,95%CI:-1.96 to-0.09;P=0.03;I2=60%]and ventilation duration(MD=-1.07,95%CI:-1.91 to-0.23,P=0.01;I2=57%)was observed in the EM group compared to usual care.EM significantly improved muscle strength[standard MD(SMD)=0.47,95%CI:0.18-0.75,P=0.001;I2=79%]and functional status(SMD=0.70,95%CI:0.40-1.00,P<0.00001;I2=81%)in ICU patients.No statistically significant difference was observed in adverse events(RR=1.72,95%CI:1.01-2.94,P=0.05;I2=31%),all-cause mortality(RR=1.10,95%CI:0.79-1.53,P=0.57;I2=30%),and QOL(SMD=0.04,95%CI:-0.07-0.15,P=0.50;I2=9%)between the two groups.CONCLUSION Initiating mobilization within 72 hours of ICU admission is associated with improved functional outcomes and reduced ICU length of stay and ventilation duration.These findings indicate that EM may be a safe option for ICU patients,contributing to lower recovery times and healthcare costs.Further extensive research is required to validate the long-term effects on survival and QOL.
文摘This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilization, and precipitation adjustment.The rainwater collection system in this program also adds the condensation water from the heating, ventilation and air conditioning （ HVAC） system and the concentration from the reverse-osmosis system used for watering greens and supplying waterscapes.By calculating, the quantity of the HVAC condensation water in summer is 3.48 m3/d, and the quantity of the reverse-osmosis concentrated water is 198 to 396 L/d.This method solves the water shortage caused by high evaporation in summer and low precipitation in winter.Supported by empirical monitoring data, the proposed method significantly increases the economic efficiency of the system during the summer period.
文摘Severe acute pancreatitis(SAP)can induce acute respiratory distress syndrome(ARDS)and abdominal compartment syndrome(ACS).Although prone position ventilation(PPV)can improve outcomes in patients with ARDS,there is significant controversy regarding its concurrent use with ACS owing to concerns of increased risk of intra-abdominal pressure(IAP).[1]We present a case of successful PPV application without adverse eff ects.
基金funded by the National Natural Science Foundation of China(NSFC)under Grant No.52278415the National Key Research and Development Program of China under Grant No.2022YFC3801104+2 种基金Hebei Provincial Department of Education Project under Grant No.QN2025304the Innovation Fund Project of Hebei University of Engineering under Grant No.SJ2401002066the Sichuan Science and Technology Program under Grant No.2023YFS0407。
文摘The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.
文摘Objective:To investigate the application effect of intelligent empowerment standardized airway management process in patients receiving mechanical ventilation.Methods:A retrospective analysis was conducted on the clinical data of 79 EICU inpatients who underwent tracheal intubation and mechanical ventilation treatment at our hospital from January 2023 to May 2025.The patients were divided into a control group(conventional airway management process,n=40)and a study group(intelligent empowerment standardized airway management process,n=39)based on the intervention protocols they received.Oral health scores,dental plaque index,oral odor,serum inflammatory markers[C-reactive protein(CRP),procalcitonin(PCT)],clinical pulmonary infection score(CPIS),as well as the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were assessed before and after treatment.Results:The baseline values of all indicators were consistent between the two groups before intervention(p>0.05).After corresponding interventions,both groups showed significant improvements in Beck oral health scores,dental plaque index,and oral odor,with more pronounced improvements observed in the study group(p<0.05).After the intervention,the research group showed a significant decrease in serum CRP and PCT levels,as well as CPIS scores(p<0.05).In contrast,the control group experienced an increase in these three indicators to a certain extent(p<0.05).Moreover,the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were all lower in the research group compared to the control group,while the nurse’s compliance rate with the protocol was higher in the research group(p<0.05).Conclusion:The standardized airway management protocol empowered by intelligent technology can significantly improve nursing compliance,benefit oral health status,reduce the risk of pulmonary infection and systemic inflammation levels,and promote rapid patient recovery,demonstrating considerable potential for widespread adoption.
基金supported by the National Natural Science Foundation of China(Grant No.52476206)the Key R&D Program of Shandong Province,China(Grant No.2025CXGC010203)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515012123)the Shandong Natural Science Foundation(Grant No.ZR2022ME008).
文摘This study aims to mitigate crosswind-induced performance degradation in Natural Draft Dry Cooling Towers used in power plants by developing and assessing windbreak configurations that enhance ventilation while minimizing additional airflow resistance.Three novel windbreak designs,namely single-windbreak configuration with curved profile,double-windbreak configuration with curved profile,and double-windbreak configuration with inverted curved profile,are proposed accordingly and evaluated against conventional solutions.Three-dimensional numerical models of a 120 m high NDDCT equipped with these windbreaks,together with a conventional Y-shaped windbreak,are developed for systematic comparison.The results demonstrate that windbreak effectiveness strongly depends on crosswind intensity.At low crosswind speeds of 0-6 m/s,the Y-shaped windbreak provides the greatest enhancement,increasing the ventilation rate by 25.45%and the heat rejection rate by 21.37%at 6 m/s compared with the no-windbreak configuration.In contrast,under moderate to strong crosswinds of 6-18 m/s,the single-windbreak configuration with curved profile exhibits superior performance.At 18 m/s,it increases the ventilation rate by 148.88%and the heat rejection rate by 79.74%relative to the baseline case,outperforming the Y-shaped windbreak by 26.59%in ventilation rate and 17.01%in heat rejection capacity.Analysis of airflow structure,temperature fields,and velocity distributions confirms that the single-windbreak configuration with curved profile more effectively suppresses crosswind penetration and promotes stable upward airflow at higher wind speeds.Based on a comprehensive assessment of aerodynamic and thermal performance,the Y-shaped windbreak is recommended for regions where crosswind speeds remain below 6 m/s,whereas the single-windbreak configuration with curved profile is preferable for sites exposed to stronger crosswinds exceeding this threshold.
文摘An automated underground mine monitoring and communication system based on the integration of new technologies is introduced to promote safety and health,operational management and cost-effectiveness.The proposed system integration considering Wireless Sensor Network(WSN) assisted Geographic Information System(GIS) enables to monitor and control underground mining applications from surface office.Based on the capabilities of WSNs,ZigBee network is adapted for near real-time monitoring,ventilation system control and emergency communication in underground mine.ZigBee nodes were developed to sense environmental attributes such as temperature,humidity and gases concentration;switching ON and OFF ventilation fans;and texting emergency messages.A trigger action plan for monitored attributes above normal and threshold value limits is programmed in the surface GIS management server.It is designed to turn the auxiliary fans on remotely or automatically in orange condition and sending evacuation messages for underground miners in unsafe(red) condition.Multi-users operation and 3D visualisations are other successful achievements of the proposed system for the underground monitoring and communication.
基金Acknowledgments This work was supported by the National Nat- ural Science Foundation of China （41172147）, the Anhui Province Science and Technology Research Plan （12010402110）, and the Shanxi Province One Hundred Distinguished Professor Plan project.
文摘The techniques of stress relief mining in low-permeability coal seams and pillarless gob side retained roadway entry using Y-type ventilation and gas drainage systems were developed to control gas outbursts and applied successfully. However, as the mining depth increasing, parts of the gas drainage system are not suitable for mines with high gas emissions. Because larger mining depths cause higher ground stresses, it becomes extremely difficult to maintain long gob side roadways. The greater deformation suffered by the roadway is not favorable lor borehole drilling for continuous gas drainage. To solve these problems, Y-type ventilation and gas drainage systems installed from a roof roadway were designed for drainage optimization. This system was designed based on a gas-enrichment zone analysis developed from mining the 11-2 coal seam in the Zhuji Mine at Huainan, Anhui Province, China. The method of Y-type gas extraction from different mine areas was applied to the panel 1112（1） in the Zhuji Mine. The absolute gas emission rate was up to 116.3 m^3/min with an average flow of 69.1 m^3/min at an average drainage concentration of nearly 85 %. After the Y-type method was adopted, the concentration of gas in the return air was 0.15 %-0.64 %, averaging 0.39 % with a ventilation rate of 2100-2750 m^3/min. The gas management system proved to be efficient, and the effective gas control allowed safe production to continue .
基金Projects 04JK197T supported by Shaanxi Education Bureau Science Foundation and 2005E202 by Shaanxi Science Foundation
文摘In order to reduce the probability of fault occurrence of local ventilation system in coal mine and prevent gas from exceeding the standard limit, an approach incorporating the reliability analysis, rough set theory, genetic algorithm (GA), and intelligent decision support system (IDSS) was used to establish and develop a fault diagnosis system of local ventilation in coal mine. Fault tree model was established and its reliability analysis was performed. The algorithms and software of key fault symptom and fault diagnosis rule acquiring were also analyzed and developed. Finally, a prototype system was developed and demonstrated by a mine instance. The research results indicate that the proposed approach in this paper can accurately and quickly find the fault reason in a local ventilation system of coal mines and can reduce difficulty of the fault diagnosis of the local ventilation system, which is significant to decrease gas exploding accidents in coal mines.
基金Project(2018YFC0808404)supported by National Key Research and Development Program of China。
文摘Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.
基金Project F010206 supported by the National Natural Science Foundation of China
文摘In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regression method to analyze the effect, of changing the rules of mine airflows, on the stability of a mine ventilation system. The amount of air （ Qj ） is determined for the major airway and an optimum regression equation was derived for Qi as a function of the independent variable （ Ri ）, i.e., the venti- lation resistance between different airways. Therefore, corresponding countermeasures are proposed according to the changes in airflows. The calculated results agree very well with our practical situation, indicating that multiple regression analysis is simple, quick and practical and is therefore an effective method to analyze the stability of mine ventilation systems.
文摘Diabetes affects approximately 30 million persons in the United States. Diabetes ketoacidosis is one of the most serious and acute complications of diabetes. At the time of presentation and during treatment of diabetic ketoacidosis(DKA), several metabolic and electrolyte derangements can ultimately result in respiratory compromise. Most commonly, hypokalemia, hypomagnesemia and hypophosphatemia can eventually lead to respiratory muscles failure.Furthermore, tachypnea, hyperpnea and more severely, Kussmaul breathing pattern can develop. Also, hydrostatic and non-hydrostatic pulmonary edema can occur secondary to volume shifts into the extracellular space and secondary to increased permeability of the pulmonary capillaries. The presence of respiratory failure in patients with DKA is associated with higher morbidity and mortality. Being familiar with the causes of respiratory compromise in DKA, and how to treat them, may represent better outcomes for patients with DKA.
文摘At high altitudes, an Aviation Oxygen Supply System （AOSS） protects pilots from low pressure and hypoxia by continuously providing oxygen corresponding to the pilots＇ dynamic respiratory properties. An AOSS mainly consists of oxygen supercharging machines which are used in a high-altitude flight cabin to supply pressurized oxygen to pilots. Therefore, it is of great significance to study the airflow dynamic characteristics of an AOSS for safe, continuous, and efficient oxygen supply. In this paper, an AOSS is firstly simplified and considered as a mechanical ventilation system. Then, its corresponding mathematical model is constructed. Next, to verify the mathematical model, a prototype AOSS with a lung simulator is proposed for an experimental study. Afterwards, to build a foundation for the optimization of the AOSS, the airflow dynamic characteristics of an aircraft are analyzed, and the effects of key parameters on the respiration system are researched. Through experimental and simulation studies, it can be concluded that the mathematical model is effective. Subsequently, for stability during the respiration process, we consider setting the equivalent throttling areas of the inspiration and expiration pipelines smaller within certain limits; additionally, an excessively high oxygen supply pressure will disturb smooth airflow, and in a low-pressure environment, the pressure can be 84 cmH20 lower than the standard atmospheric pressure. This research can be referred to in the design of an oxygen supply system and the study on optimization of airflow dynamic characteristics.
文摘The underfloor air distribution(UFAD)system has not been able to penetrate the residential and commercial air conditioning industry significantly until now.To date,the most notable applications are found in datacenters because of their more demanding thermal stratification and cooling requirements.In addition to highlighting the advantages of the UFAD system over the traditional overhead(OH)system,this study compares various ventilation layouts for a UFAD system.Four different UFAD ventilation layouts are compared and one OH layout.The results show that using multiple swirl-type diffusers creates a more uniform floor-to-knee temperature and less air recirculation than the rectangular grille-type diffusers.Placing the return vents on the sides of the room creates a cooler environment by isolating recirculating air to a smaller space.At the end of the study,a design guide matrix is presented to summarize how the supply and return vent layout affects air conditioning performance.
文摘A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a mine, operators need to know the cause and effect of any changes requested from the VOD system. The sensitivity analysis is developed through generating a cause and effect matrix of sensitivity factors on given parameter changes in a ventilation system. This new utility, which was incorporated in the 3D-CANVENT mine ventilation simulator, is able to predict the airflow distributions in a ventilation network when underground conditions and ventilation controls are changed. For a primary ventilation system, the software can determine the optimal operating speed of the main fans to satisfy the airflow requirements in underground workings without necessarily using booster fans and regulators locally. An optimized fan operating speed time-table would assure variable demand-based fresh air delivery to the production areas effectively, while generating significant savings in energy consumption and operating cost.
基金the National Natural Science Foundation of China(No.11902153)the Natural Science Foundation of Jiangsu Province(No.BK20190378)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘This study conducts an evaluation of air quality,dispersion of airborne expiratory pollutants and thermal comfort in aircraft cabin mini-environments using a critical examination of significant studies conducted over the last20 years.The research methods employed in these studies are also explained in detail.Based on the current literature,standard procedures for airplane personal ventilation and air quality investigations are defined for each study approach.Present study gaps are examined,and prospective study subjects for various research approaches are suggested.
文摘Diesel particulate matter （DPM） is considered to be carcinogenic after prolonged exposure. With more diesel- powered equipment used in underground mines, miners＇ exposure to DPM has become an increasing concern. This paper used computational fluid dynamics method to study the DPM dispersion in a dead-end entry with loading operation. The effects of different push-pull ventilation systems on DPM distribution were evaluated to improve the working conditions for underground miners. The four push-pull systems considered include： long push and short pull tubing; short push and long pull tubing, long push and curved pull tubing, and short push and curved pull tubing. A species transport model with buoyancy effect was used to examine the DPM dispersion pattern with unsteady state analysis. During the 200 s of loading operation, high DPM levels were identified in the face and dead-end entry regions. This study can be used for mining engineer as guidance to design and setup local ventilation, select DPM control strategies and for DPM annual training for underground miners.
文摘With depletion of shallow deposits,the number of underground mines expected to reach more than 3 km depth during their lifetime is growing.Although surface cooling plants are mostly effective in mine airconditioning,usually secondary cooling units are needed below 2 kmdepth.This need emerges due to the elevated thermal impacts caused by auto-compression of mine air as well as heat emissions from strata and mine machinery.As a result,in cold climates,like Canada,ultra-deep mines need their secondary underground cooling plants running year-round while the intake air must be heated to protect the sensitive machinery and liners from freezing during the winter season.To cool mine air,horizontal bulk-airconditioners with direct spray cooling systems are commonly used due to their high performance.Conventionally,sprayed water in bulk-air-coolers are mechanically circulated and refrigerated in coupled refrigeration plants.This set up can be transformed to a natural cooling/heating process by resurfacing the warm underground bulk-air-cooler spray water for mine air heating on the surface and re-sinking the chilled water for cooling in the underground bulk air coolers.This could significantly cut-down the fossil-fuel consumption in burners for mine air pre-conditioning and refrigeration cost when applicable.This paper presents an anonymous real-life example to study the feasibility of the proposed idea for an ultra-deep Canadian mine.
基金Project 0424220161 supported by Science and Technology Foundation of Education Bureau of Henan Province
文摘Based on the basic content of advanced technology,safety and reliability, and economic reasonability and the definition of mine ventilation system, 16 assessment indexes of ventilation system are put forward from the point of 8 aspects such as mine ventilation power, ventilation network, ventilation equipments, ventilation quality, ventilation monitoring, capacity of preventing and fighting disaster, ventilation consumption of power, and the capacity of ventila- tion system. A new assessment index system is put forward and has a good effect after being applied in coal mines.
