Smoking Control Research Articles

Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust

High-temperature smoke generated by tunnel fires is the most important factor causing casualties. To explore the influence of natural wind on fire smoke movement in an extra-long highway tunnel based on the Taihang Mountain Tunnel, the distribution law of natural wind in the tunnel was obtained by on-site monitoring of the meteorological conditions at the tunnel site. A three-dimensional fire dynamics tunnel model considering an inclined shaft smoke exhaust was established, and the influence of natural wind on tunnel temperature distribution, smoke spread and smoke exhaust efficiency was studied. The results show that the natural wind speed of the Taihang Mountain Tunnel is mainly concentrated at 0~3 m/s. The main wind direction of the natural wind on the left tunnel is opposite to the driving direction, and the distribution probability of the main wind direction in each section is 81.27% and 72.15%, respectively. The main wind direction of the right tunnel is the same as the driving direction, and the distribution probability of the main wind direction in each section is 56.78%, 69.73%, 67.32% and 64.65%, respectively. The negative natural wind can inhibit the smoke spread downstream of the smoke exhaust port, but it is not conducive to the smoke exhaust. The positive natural wind promotes the smoke spread to the downstream of the smoke exhaust port, and the larger the natural wind speed, the longer the spread length. Natural wind reduces the smoke exhaust efficiency. For positive or negative natural wind with a guaranteed rate of 70%, the smoke exhaust efficiency is reduced by 27.76% and 15.59%, respectively, compared with the condition without natural wind. The research results can provide a useful reference for the design of fire smoke exhausts and smoke control schemes in extra-long highway tunnels.

Full-scale experimental study on combustion characteristics and smoke temperature of double-source fires in different tunnels

Through a series of full-scale fire tests conducted in three different tunnels, the common characteristics of combustion and smoke temperature of double pool fires in actual operation tunnel environments are investigated. The evolution process of the coupling effects of shielding entrainment and thermal feedback enhancement is revealed. It is found that the ventilation state and the fire source spacing can alter the dominant relationship between the shielding entrainment effect and the thermal feedback enhancement effect, resulting in different evolution patterns of combustion characteristics and smoke flow patterns of double pool fires in tunnels. The heat release rate increases by 4 times when the double pool fire flames merge under the longitudinal ventilation compared with the double pool fire flames without fusion under the natural ventilation. The flame tilt angles of double pool fires were determined through the image processing method, and the prediction model of the flame inclination angle of downstream fire sources was established, considering fire source spacing. At the same time, the characteristic of temperature measured by Fiber Bragg Grating in double-source fire scenarios was investigated, developing a model to predict the longitudinal temperature rise distribution. It is found that the maximum temperature rise prediction model based on steady-state fire has poor applicability in the weak-plume fire scenario of full-scale tunnels. The analysis of the smoke flow patterns shows that the two-stage ventilation is more suitable for smoke control compared to full longitudinal ventilation in tunnel double-source fire accidents, especially for ensuring the safety of individuals trapped in the area between the two fire sources.

Shanghai and the Smoke Fiend: Obstacles to the Control of Urban Smoke, 1869–1943

As Shanghai industrialised, its Chinese and European residents suffered the scourge of coal-powered cities: smoke. Air pollution became a multi-sensory reality. Residents could see, smell, feel and taste the smoke that shrouded the city. Inspired by anthropologists and historians of the senses, we mined Chinese- and English-language sources to document the emergence of experiences of air pollution in Shanghai. Concerns began earlier than other historians have appreciated. The vigorous complaints from all parts of Shanghai society illuminate how the city’s governments attempted to respond to the crisis and mitigate the toxic consequences of industrialisation. We found many obstacles to the success of the governments’ approaches. While other scholars have emphasised Shanghai’s fractured governance, we also found evidence of financial conflicts of interest, industry obfuscation and anti-Chinese racism. Our work expands the understanding of the history of air pollution in China and offers a model that can be used to extend global histories of air pollution beyond their traditional focus on Europe and North America.

Smoke diffusion mechanism and mitigation design for fire accidents in a tunnel-groove structure of a large hydropower station

In this study, field tests and numerical simulations were conducted to investigate the smoke diffusion mechanism and mitigation design for a fire accident occurring in a special hybrid structure, i.e., the tunnel-groove structure (TGS) of a large hydropower station. It is found that the characteristics of the smoke spread in the TGS include the smoke temperature attenuation, incomplete chimney effect and smoke entrainment. The combustion of the polyurethane flame-retardant material is controllable and extinguishes immediately after the fire source is removed. However, there is a fire risk in a relatively closed space under the conditions of strong winds, especially at the connection port with the external environment, due to the wind tunnel and chimney effects, which result in rapid smoke diffusions. During the fire accident, the smoke first fills in the entire tunnel (89 m long), then propagates upward along the groove, and finally reaches the dam top (115 m above the tunnel) in 10 s. The heat release rate (HRR) was determined as approximately 50 MW and the maximum velocity of the smoke spread along the dam surface could reach 10 m/s. As a result, nearly no time was available for the workers in the groove to evacuate when the fire accident occurred. Sensitivity analyses were further conducted to study the effects of different parameters, such as the HRR, the air inflow velocity and the radial gate opening, on the smoke diffusion in the TGS. A horizontal smoke plate (HSP) was proposed for the temporary smoke control to prevent life from losses due to the smoke diffusion in the TGS. The safe and dangerous zones near the dam surface were identified by analyzing the characteristics of the smoke temperature and visibility. It was finally concluded that the HSP can mitigate the smoke and heat along the groove. The results from this study may serve as a useful reference for the smoke control design in the TGS or other similar structure configurations.

LRG1 promotes the apoptosis of pulmonary microvascular endothelial cells through KLK10 in chronic obstructive pulmonary disease.

Cigarette smoking is one of the most important causes of COPD and could induce the apoptosis of pulmonary microvascular endothelial cells (PMVECs). The conditional knockout of LRG1 from endothelial cells reduced emphysema in mice. However, the mechanism of the deletion of LRG1 from endothelial cells rescued by cigarette smoke (CS) induced emphysema remains unclear. This research aimed to demonstrate whether LRG1 promotes the apoptosis of PMVECs through KLK10 in COPD. Nineteen patients were divided into three groups: control non-COPD (n=7), smoker non-COPD (n=7), and COPD (n=5). The emphysema mouse model defined as the CS exposure group was induced by CS exposure plus cigarette smoke extract (CSE) intraperitoneal injection for 28 days. Primary PMVECs were isolated from the mouse by magnetic bead sorting method via CD31-Dynabeads. Apoptosis was detected by western blot and flow cytometry. LRG1 was increased in lung tissue of COPD patients and CS exposure mice, and CSE-induced PMVECs apoptosis model. KLK10 was over-expressed in lung tissue of COPD patients and CS exposure mice, and CSE-induced PMVECs apoptosis model. LRG1 promoted apoptosis in PMVECs. LRG1 knockdown reversed CSE-induced apoptosis in PMVECs. The mRNA and protein expression of KLK10 were increased after over-expressed LRG1 in PMVECs isolated from mice. Similarly, both the mRNA and protein levels of KLK10 were decreased after LRG1 knockdown in PMVECs. The result of co-immunoprecipitation revealed a protein-protein interaction between LRG1 and KLK10 in PMVECs. KLK10 promoted apoptosis via the down-regulation of Bcl-2/Bax in PMVECs. KLK10 knockdown could reverse CSE-induced apoptosis in PMVECs. LRG1 promotes apoptosis via up-regulation of KLK10 in PMVECs isolated from mice. KLK10 promotes apoptosis via the down-regulation of Bcl-2/Bax in PMVECs. There was a direct protein-protein interaction between LRG1 and KLK10 in PMVECs. Our novel findings provide insights into the understanding of LRG1/KLK10 function as a potential molecule in COPD.

A qualitative study to control adolescent smoking behaviour in junior high school.

To evaluate efforts made to help young people curb smoking behaviour. The qualitative study was conducted from January to February 2020 at 3 junior high schools in Banda Aceh, Indonesia, after approval from the ethics review committee of the University of Indonesia. The participants were students in grades 7 and 8. Data was collected through interviews, documentation and field notes. Data was subjected to construct and content validation, and was qualitatively analysed using NVivo 12 Plus. Of the 16 students, 2(12.5%) were from grade 7, and 14(87.5%) from grade 8. Overall, 12(75%) adolescents had smoked. There were 5 themes that emerged: smoking compulsion, adolescent perspectives on smoking behaviour, knowledge of the risks associated with smoking, obstacles to quitting, and smoking control strategies. To curb adolescent smoking, there were 2 themes: barriers to quitting smoking, and smoking control strategies. Efforts to curb smoking should focus on increasing adolescent self-control.

A Study on Securing the Safety of Electric Vehicle Charging Areas

This study analyzes the risk and risk factors of fire based on the location of a specific firefighting object where an electric vehicle charging area is installed, and proposes a way to ensure safety through fire risk assessment. First, as an institutional measure, individuals should be prohibited from installing charging areas in high-risk underground parking lots. Second, as a managerial measure, fire agencies should develop and disseminate standardized charging-area checklists and manuals. Third, as a structural measure, the charging area should be fire-protected or bulkheads should be installed. Fourth, as a facility measure, a dedicated firefighting facility and smoke control and ventilation systems should be installed in the charging areas. Fifth, firefighting measures should be equipped with dedicated firefighting equipment in the case of new constructions.

Analysis of parameters for spray-local exhaust ventilation (SLEV) to minimize high-temperature smoke pollutants and reduce energy consumption

Industrial buildings often face limitations in placing local exhaust ventilation (LEV) near pollution sources, which can lead to ineffective control of high-temperature smoke. This study explores the integration of spray with local exhaust ventilation (SLEV) as a solution for smoke control and energy savings. The research identified a design law for spray parameters and developed a formula to calculate SLEV ventilation flow rate that considers the impact of spray. Results indicate that the spray field overlapping coefficient plays a key role in characterizing the position and spacing of multi-nozzles. As the spray field overlapping coefficient increases, the spray dust reduction performance indicator linearly increases, while the capture efficiency follows a pattern that aligns with the Boltzmann curve model. The optimal range for the spray field overlapping coefficient to achieve high efficiency in SLEV is between 0.45 and 0.55. The formula for ventilation flow rate calculation is applicable to common conditions with smoke velocities ranging from 4 to 12 m/s (Ar: 0.0149–0.1339). SLEVs demonstrate a 35.22 % improvement in dust removal efficiency and over 20 % energy savings compared to LEVs, contributing to the development of high-efficiency, energy-saving systems for sustainable industrial production.

Study on the influence of slope on smoke overflow and temperature characteristics of carriages with lateral openings in subway fires

This research explores the impact of slope on fire hazards in train carriages with multiple lateral openings in underground tunnel fires. Utilizing FDS software, a comprehensive full-scale fire scenario is simulated to study smoke overflow and temperature distribution in inclined tunnels with slopes ranging from 0 % to 4 % and Heat Release Rates (1 MW–10 MW) under natural ventilation. The study reveals that smoke mainly originates from the upstream end door and the door near the fire source, with smoke overflow from the upstream end door increasing significantly with the slope. Fire power has minimal impact on smoke overflow. When fire power is large, the longitudinal temperature distribution inside the carriage exhibits an overall increasing trend with increasing slope. The maximum carriage temperature decreases steadily with the slope for Q˙ ≤ 5 MW, while the slope has less influence on temperature variation for Q˙ > 5 MW. A modified prediction model is proposed to forecast maximum ceiling temperature during fire scenarios, providing valuable insights for structural fire protection, fire detection, and smoke control in metro areas. This study enhances understanding of smoke movement and temperature distribution in train carriage fires in inclined tunnels, contributing to engineering practices.

Numerical investigation on smoke control with new‐style horizontal smoke baffle in an immersed road tunnel

AbstractTo investigate the improvement induced by horizontal smoke baffles during lateral smoke exhaust, an immersed road tunnel with various horizontal smoke baffles positioned below the lateral exhaust vent was studied numerically. Together with the velocity field characteristics, the temperature distribution was investigated near the lateral smoke exhaust vent, followed by the analysis of lateral smoke exhaust efficiency under different horizontal smoke baffles. Results showed that after installing the horizontal smoke baffle, there was a significant decrease in the extracted cold air, while the high‐temperature smoke in the exhaust vent increases, indicating the plug‐holing is effectively suppressed. It is known that the efficiency of smoke exhaust increases when the length exceedance ratio of the horizontal smoke baffle is smaller than 100%, while it changes slightly when the baffle length continues to increase. When the width ratio of horizontal baffle is smaller than 40%, the efficiency of smoke exhaust increases with the baffle width and then changes slightly with a wider smoke baffle. With a larger aspect ratio, the wider and shorter lateral exhaust vent is beneficial for improving the lateral smoke exhaust. Under the current conditions, the case shows the optimal smoke exhaust performance with a horizontal baffle length exceedance ratio of 100%, a baffle width ratio of 40%, and exhaust vent aspect ratio of 3:1. Finally, an empirical model is developed to describe the improvement of smoke exhaust efficiency caused by horizontal smoke baffle. These outcomes are helpful to the design of lateral smoke extraction system in road tunnels.

Advancements in smoke control strategies for metro tunnel cross-passage: A theoretical and numerical study on critical velocity and driving force

Cross-passage is a commonly encountered structure within metro tunnels, providing a swift route for evacuating personnel from the accident tunnel to the safe tunnel opposite. Ventilation in the cross-passage of metro tunnels is established through the collaborative operation of ventilation systems on both sides of the tunnel. Concurrently, smoke movement within the metro tunnel is impacted by factors such as train blockage and the accumulation of heat within the train carriages. The former correlations need further refinement to predict the critical velocity and driving force required to prevent smoke from spreading into a metro tunnel cross-passage. One-dimensional theoretical analysis and full-scale cold smoke experiments were performed to investigate the relationship between the air supply parameters of tunnel fans on both sides and the ventilation velocity in the cross-passage. A calculation model of fan type selection in the opposite side safe tunnel for smoke control in the tunnel cross-passage is proposed. The influence of train location, fire heat release rate, and main tunnel ventilation velocity on critical velocity in the cross-passage was quantified by numerical simulations. The results show that the critical velocity in the cross-passage under unobstructed conditions surpasses that under blocked conditions. Meanwhile, the critical velocity exhibits relative stability under both unobstructed and blocked conditions. On the basis of the dimensionless analysis, a piecewise function was proposed to predict the critical velocity in tunnel cross-passage. The outcomes of this study provide valuable guidance for the implementation of fire prevention and smoke control measures in tunnels with similar structures.

An apparatus and procedure for studying discounting of real outcomes of money and aversive sound.

We developed and examined a laboratory preparation with adult humans that pits shorter term avoidance over longer term positive reinforcement and may serve as a useful laboratory functional analogue of problematic behavior. Participants were exposed to choices between (1) avoiding an aversive sound and acquiring no money or (2) listening to an aversive sound for a set duration and then receiving money. The first choice, avoiding an aversive sound and acquiring no money, was conceptualized as immediate negative reinforcement and no positive reinforcement, whereas the latter choice, listening to an aversive sound for a set duration and then receiving money, was conceptualized as a potential positive punisher paired with a larger later positive reinforcer. We manipulated the duration of the sound and the magnitude of money to identify the point at which individual participants' choices changed from avoiding the sound to choosing the sound plus money. As the sound duration increased, the choice of listening to the sound and receiving money decreased. Similar functions were observed with two different monetary magnitudes. The model has potential applicability to real-world problems such as smoking, addiction, gambling, anxiety disorders, and other impulse control disorders.

Experimental study of smoke characteristics in a double-deck tunnel with multiple point extraction using a branch pipe

A reduced scale 1:8 double-deck tunnel model was built to study smoke control performance of a semi-transverse ventilation system using a branch pipe to connect the lower deck tunnel to the upper smoke duct. 41 experiments were conducted to analyze the effects of different activation modes of smoke vents, heat release rate (HRR), and exhaust smoke rates on smoke spread distance. An optimum smoke control mode was found by activating two vents near the fire source when the heat release rate was 44.19 kW (8 MW at full scale) and the fan's extraction rate was 0.66 m3/s (120 m3/s at full scale) using a branch pipe. Results showed that as HRRs rise, the smoke spread distance first increases and then remains constant. The ratio of the smoke spreading distance on the upstream side of the fire to the total smoke spreading distance was 0.4 in this experimental setup. Furthermore, fire smoke spread characteristics were quantified for a typical ventilation design.

The Efficacy of the SinHumo App Combined With a Psychological Treatment to Quit Smoking: A Randomized Clinical Trial.

This study assessed the efficacy of the SinHumo App combined with a cognitive-behavioral smoking cessation treatment on 12-month follow-up abstinence, compared with the same smoking cessation treatment and a control App. A sample of 288 treatment-seeking people who smoke were randomized: SinHumo App plus smoking cessation treatment (n = 140) and control App plus smoking cessation treatment (n = 148). The primary outcome was 7-day point prevalence abstinence (PPA) at the 12-month follow-up. Secondary outcomes were abstinence rates at the end of the intervention and 3- and 6-month follow-ups, cigarette per day (CPD) reduction over the 12-month follow-up, intervention engagement, and satisfaction. Intention-to-treat analyses showed nonsignificant differences in self-reported 7-day PPA at the 12-month follow-up (37.1 and 42.6%, respectively; OR = 0.80). No significant differences were found in abstinence at the end of the treatment (68.6 vs. 62.8%) nor on 7-day PPA at 3- (35.7 vs. 45.9%) and 6-month (35.0 vs. 41.2%) follow-up. Complete case and multiple imputation analyses yielded similar results for abstinence outcomes. A significant reduction in CPD across the 12-month follow-up in the subsample of participants who smoked was observed, but nonsignificant differences between conditions were found. Higher engagement with the SinHumo App was a significant predictor of 12-month abstinence. Satisfaction with the intervention was high and similar in both groups. High abstinence rates over the 12-month follow-up and satisfaction were found in both conditions. The inclusion of the SinHumo App did not improve abstinence rates in the intervention. Scarce research has examined the long-term efficacy of smoking cessation treatments, including Apps, to support the quitting process. The present randomized controlled trial contributes to the existing literature about including information and communication technologies in behavior change interventions. The development of effective smoking cessation apps and information and communication technologies-based interventions is crucial for reducing the prevalence of smoking, as these interventions have the potential to reach a large number of people who smoke and reduce access-related barriers to treatment.

Experimental study on the performance of synergistic ventilation system combining shaft with mechanical ventilation in extra-long road tunnels

Ventilation shafts are widely equipped in extra-long road tunnels. Due to the plug-holing phenomenon, it may be impossible to improve smoke extraction performance solely by increasing extraction velocity in a traditional ventilation shaft. Taking reference from practices in mine ventilation shafts, a novel mechanical board-coupled ventilation shaft (MBCS) was introduced. A total of 120 experiments in a 1:20 reduced-scale tunnel model were conducted to validate the effectiveness of the novel shaft. The effects of shaft height, board location, and extraction velocity were investigated, and the interaction dynamic mechanism of synergistic smoke extraction between fan-driven and shaft-driven was revealed. The results indicate that the novel MBCS can achieve better smoke extraction performance as the extraction velocity increases. Besides, compared to the traditional MBCS in our previous study, the smoke extraction efficiency of the novel MBCS improves by 19.8 %, the heat extraction performance improves by 75.7 %. Moreover, based on theoretical and dimensional analysis, a model to analyze the dynamic mechanism of synergistic smoke extraction was established, which may provide positive insights for smoke control and extraction design both in extra-long road tunnels and mine ventilation shafts.

Study on the Smoke Control Performance of Air Curtains in Emergency Stairwells of Multi-Unit Residential Buildings

Recently, in high-rise buildings, pressurization systems have been installed in emergency stairwells to prevent the ingress of smoke. However, in older buildings, these stairwells often lack pressurization systems, while in buildings with fewer stories, such systems are not typically installed. This study conducts simulations and a hot smoke test to evaluate the performance of air curtains in blocking smoke and toxic gases in outdoor emergency stairwells where additional pressurization equipment cannot be installed. The simulation results showed that air curtains installed perpendicular to the floor were useful at preventing smoke ingress, and higher wind speeds increased their effectiveness. It is believed that air curtains can partially reduce smoke ingress in stairwells of older buildings or low-rise structures without pressurization systems, thereby ensuring fire safety.

Contingency management for smoking cessation for individuals with overweight or obesity: A randomized controlled trial

BackgroundInterventions for quitting smoking and weight control among individuals with excess weight are scarce. Our study evaluated the effectiveness of cognitive behavioral therapy (CBT) plus contingency management (CM) in this population, and examined whether CM for smoking cessation improved CBT treatment outcomes at end of treatment (EOT) and at 1-, 3-, 6-, and 12-month follow-ups (FU). MethodsIn an 8-week randomized clinical trial, 120 adults who smoke with overweight or obesity (54.16% females; MBMI = 31.75 ± 4.31) were randomly assigned to CBT for both quitting smoking and weight control (n = 60) or the same treatment plus CM for smoking cessation (n = 60). Outcome variables were compared (i.e., treatment completion, smoking abstinence, weight change and secondary outcomes). ResultsAt EOT, the CBT + CM group achieved 78.33% 7-day point-prevalence abstinence rates compared to 61.67% in the CBT group (p = .073), and rates declined over time (12-month FU: 18% vs 12%). Participants who attained abstinence weighed more compared to baseline at EOT (Mkg = 1.07; SD = 1.88) and over time (12-month FU: Mkg = 4.19; SD = 4.31). No differences were found between the two groups in outcome variables. ConclusionsBoth interventions were effective in promoting abstinence and reducing tobacco use over time. Combining CBT with CM for smoking cessation did not improve treatment outcomes in individuals with overweight or obesity compared to CBT only. Future studies should evaluate whether implementing CM for weight maintenance helps control post-cessation weight gain in this population.

Preliminary Efficacy of a Cognitive Behavioral Therapy-Based Smartphone App for Smoking Cessation in China: Randomized Controlled Pilot Trial.

The overall prevalence of cigarette smokers in China is very high, and China's total cigarette consumption makes up more than 40% of the world's consumption. In view of the lack of smoking cessation services and social support in China and the effectiveness of mobile phone apps for quitting smoking in other countries, we carried out a smartphone app-based smoking cessation trial in China. This study aimed to evaluate the efficacy of a cognitive behavioral therapy (CBT)-based smoking cessation smartphone app among smokers seeking treatment in China. We conducted a randomized controlled, web-based pilot clinical trial in China between February 23 and June 27, 2021. Eligible participants were randomly assigned to the smoking cessation app intervention group or the control group in a ratio of 1:1. The intervention group received the CBT smoking cessation intervention using a smartphone app, and the control group received a "thank you" message. The intervention was 4 weeks long, and the patients were followed up for 4 weeks. The primary outcome was self-reported continuous smoking abstinence at week 4 after the quit date. The secondary outcomes included self-reported 7-day point prevalence of smoking abstinence; reduction of the number of cigarettes smoked per day at weeks 1, 2, 3, and 4; and program acceptability. A total of 973 people were recruited to quit smoking, of whom 262 completed basic information, 56 were excluded, and 206 were randomized and included in the final analysis. There were 189 (91.7%) men and 17 (8.3%) women, with an average age of 34.46 (SD 7.53) years and an average daily smoking rate of 15.93 (SD 7.10) cigarettes/day. We found 30 (29.7%) of the 101 participants in the intervention group and 7 (6.7%) of the 105 participants in the control group reported continuous smoking cessation after the quit date at week 4 (odds ratio 5.92, 95% CI 3.78-9.26; P<.001). The 7-day point prevalence abstinence rate of the intervention group varied from 42.6% (43/101) to 46.5% (47/101) after 1, 2, 3, and 4 weeks, while the control group varied from 18.1% (19/105) to 26.7% (28/105). Compared to the control group, continued smokers consumed 1.5-3.0 fewer cigarettes per day in the intervention group. The overall program got positive user feedback with a high satisfaction rate (66/87, 76%) and an average Mobile Application Rating Scale user version score of 3.46. Our pilot study provided preliminary evidence that the CBT-based smoking cessation smartphone app led to improved smoking quit rates versus control in Chinese smokers. The study demonstrated the CBT-based smartphone app may be an effective and feasible digital treatment model to help smokers quit, which may improve smoking cessation service quality and accessibility in China. ClinicalTrials.gov NCT04421170; https://clinicaltrials.gov/study/NCT04421170. RR2-10.1136/bmjopen-2020-041985.

Research on the Optimal Spacing of Multiple Roof Smoke Blocking Structures in a Long Corridor

In a long and narrow corridor, the installation of roof smoke blocking structures is a measure to slow down the spread of fire smoke. When employing multiple smoke blocking structures, the spacing between these structures is a critical parameter that needs to be considered for optimal effectiveness. This paper analyzes the smoke blocking performance of double structures at different spacing and measures the smoke flow velocity both upstream and downstream of the double structures. According to the analysis of the smoke velocity vector obtained from numerical simulation, the smoke can be divided into three zones based on the flow state of the smoke after passing through the front smoke screen structure, namely the vortex zone, surge wave zone, and steady flow zone. When the rear smoke screen is located in the surge zone, the smoke blocking effect is optimal. Analysis of the morphology of the smoke layer indicates that the length of the vortex region is directly proportional to the upstream smoke flow velocity. The numerical and experimental results both indicate that an excessively large or small spacing between the structures fails to achieve optimal smoke control effectiveness. When the spacing is within an optimal range, the smoke velocity is the lowest. Finally, using a real architectural corridor as a case background, this paper presents a design example of roof smoke blocking structures. In order to arrange as many smoke blocking structures as possible, an appropriate spacing between the structures should be slightly larger than the vortex region. The smoke control effectiveness of multiple roof structures was validated through numerical simulation. As a result, the time required for smoke to pass through the corridor increases by 110 s.

Upregulation of Notch Signaling and Cell-Differentiation Inhibitory Transcription Factors in Stable Chronic Obstructive Pulmonary Disease Patients.

Notch signaling is involved in the prevention of cell differentiation and cell fate in various organs, including the lungs. We aimed to determine the transcriptomic and protein expression of Notch receptors, their ligands, and related transcription factors in stable COPD. The expression and localization of Notch receptors, their ligands, and related transcription factors were measured in bronchial biopsies of individuals with stable mild/moderate (MCOPD) (n = 18) or severe/very severe (SCOPD) (n = 16) COPD, control smokers (CSs) (n = 13), and control nonsmokers (CNSs) (n = 11), and in the lung parenchyma of those with MCOPD (n = 13), CSs (n = 10), and CNSs (n = 10) using immunohistochemistry, ELISA tests, and transcriptome analyses. In the bronchial biopsies, Notch4 and HES7 significantly increased in the lamina propria of those with SCOPD compared to those with MCOPD, CSs, and CNSs. In the peripheral lung bronchiolar epithelium, Notch1 significantly increased in those with MCOPD and CSs compared to CNSs. ELISA tests of lung parenchyma homogenates showed significantly increased Notch2 in those with MCOPD compared to CSs and CNSs. Transcriptomic data in lung parenchyma showed increased DLL4 and HES1 mRNA levels in those with MCOPD and CSs compared to CNSs. These data show the increased expression of the Notch pathway in the lungs of those with stable COPD. These alterations may play a role in impairing the regenerative-reparative responses of diseased bronchioles and lung parenchyma.