Development of the Separate Air-Supply Type of Pressurization Smoke Control System for the Stairwells of High-Rise Buildings in Korea

The pressurization smoke control system has been commonly used as a smoke control system at the emergency stairs of high-rise buildings. However, a higher possibility of overpressure between the lobby and the accommodation or pressure drop in the lobby could lead to failure in achievement of the purpose of pressurization system, particularly when supplying the leakage and supplementary air flow through one air-supply path at a time. To improve this particular issue, the devise configurations, as well as the different ways to supply the leakage and supplementary air flow through the different flow passages have been proposed. The performance of the trial product was evaluated on the test bed, ultimately providing a safe evacuation environment if high-rise buildings fired.

Small-scale fire tests in the underwater tunnel section model with new sidewall smoke extraction

The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea tunnel.To solve the smoke exhaust problem of a super large cross-section subsea tunnel,the tunnel has a new smoke exhaust system that combines a horizontal smoke exhaust cross section at the top and sidewall smoke exhaust holes.In order to evaluate the potential fire hazards of this type of tunnel,a 1:30 tunnel model was established and 140 smallscale experiments on underwater tunnel fires were conducted.By changing the fire power,fire location,and fan operation mode,different scenarios of submarine immersed tunnel fire were simulated and the related key parameters such as fire smoke diffusion behavior and smoke temperature distribution were studied.On this basis,the optimal smoke control strategy was proposed for different fire scenarios.The research results indicate that the new smoke exhaust system can fully utilize the smoke flow characteristics,significantly improve smoke exhaust efficiency,and increase available evacuation time,thus further enhancing the fire safety of super large cross-section subsea tunnels.

Associations of lifestyle and diet with the risk of nasopharyngeal carcinoma in Singapore:a case–control study

Background: Nasopharyngeal carcinoma(NPC) is a commonly diagnosed cancer in Southeast Asia. Many studies have examined the risk factors for NPC, yet the roles of some risk factors remain inconclusive. The purpose of this study was to examine associations between modifiable lifestyle factors and the risk of NPC in the Singaporean population.Methods: We conducted a case–control study in Singapore with 300 patients and 310 controls who were recruited between 2008 and 2012. Each control was selected and individually matched to each patient based on sex, ethnicity, and age(±5 years). A total of 290 pairs of cases and controls were matched successfully. We examined lifestyle factors such as tobacco smoking, alcohol drinking, various salted and preserved food consumption, and weaning practices.Results: After adjusting for covariates, multivariate analysis showed that those participants who were current smokers and had ever smoked tobacco had a higher risk of NPC than participants who had never smoked, with odds ratios(ORs) of 4.50(95% confidence interval [CI] 2.58–7.86; P < 0.001) and 2.52(95% CI 1.54–4.12; P < 0.001), respectively. Those who consumed salted vegetables at least once a week also showed a significantly increased risk of NPC than those who never or rarely consumed salted vegetables, with an OR of 4.18(95% CI 1.69–10.38; P = 0.002).Conclusion: Smoking(currently and ever-smoked) and consuming salted vegetables once a week or more were lifestyle risk factors for NPC, and changes of these factors for the better may reduce the risk of NPC.

Open abdomen in gastrointestinal surgery:Which technique is the best for temporary closure during damage control?

AIM To compare the 3 main techniques of temporary closure of the abdominal cavity,vacuum assisted closure(vacuum-assisted closure therapy- VAC),Bogota bag and Barker technique,in damage control surgery.METHODS After systematic review of the literature,33 articles were selected to compare the efficiency of the three procedures.Criteria such as cost,infections,capacity of reconstruction of the abdominal wall,diseases associated with the technique,among others were analyzed.RESULTS The Bogota bag and Barker techniques present as advantage the availability of material and low cost,what is not observed in the VAC procedure.The VAC technique is the most efficient,not only because it reduces the tension on the boarders of the lesion,but also removes stagnant fluids and debris and acts at cellular level increasing cell proliferation and division.Bogota bag presents the higher rates of skin laceration and evisceration,greater need for a stent for draining fluids and wash-ups,higher rates of intestinal adhesion to the abdominal wall.The Barker technique presents lack of efficiency in closing the abdominal wall and difficulty on maintaining pressure on the dressing.The VAC dressing can generate irritation and dermatitis when the drape is applied,in addition to pain,infection and bleeding,as well as toxic shock syndrome,anaerobic sepsis and thrombosis.CONCLUSION The VAC technique,showed to be superior allowing a better control of liquid on the third space,avoiding complications such as fistula with small mortality,low infection rate,and easier capability on primary closure of the abdominal cavity.

Damage control orthopaedics: State of the art

Damage control orthopaedics(DCO) originally consisted of the provisional immobilisation of long bone-mainly femur-fractures in order to achieve the advantages of early treatment and to minimise the risk of complications, such as major pain, fat embolism, clotting, pathological inflammatory response, severe haemorrhage triggering the lethal triad, and the traumatic effects of major surgery on a patient who is already traumatised(the "second hit" effect). In recent years, new locations have been added to the DCO concept, such as injuries to the pelvis, spine and upper limbs. Nonetheless, this concept has not yet been validated in well-designed prospective studies, and much controversy remains.Indeed, some researchers believe the indiscriminate application of DCO might be harmful and produce substantial and unnecessary expense. In this respect, too,normalised parameters associated with the acid-base system have been proposed,under a concept termed early appropriate care, in the view that this would enable patients to receive major surgical procedures in an approach offering the advantages of early total care together with the apparent safety of DCO. This paper discusses the diagnosis and treatment of severely traumatised patients managed in accordance with DCO and highlights the possible drawbacks of this treatment principle.

Design of Mechanical Smoke Exhaust System in Large Space of Convention Center

The volumetric flow rate of smoke generated from the fire in large space often reaches to hundreds of thousands CMH because of extended floor height and as it’s more difficult to isolate the smoke to the limited area, comparing to normal-scale building, design and operation of effective smoke control system for large space is more than important. In this study, with the analysis model for such a large space as exhibition hall or conference room in conventional center, design of mechanical smoke exhaust system was conducted based on currently-available design standard which was then followed by numerical analysis of the design using 3D numerical analysis method. For conference room at 2.0 MW heat release rate, 99,173 CMH flow rate is required, if smoke layer is maintained at 60% of the floor height and for exhibition hall at 8.8 MW with 80% of floor height, flow rate required is 219,802 CMH, which are incorporated into the design. In view of 3D numerical analysis, accuracy of the design according to algebraic expression is sufficient.

Smoke movement in a tunnel of a running metro train on fire

Research on the distribution of smoke in tunnels is significant for the fire emergency rescue after an operating metro train catches fire. A dynamic grid technique was adopted to research the law of smoke flow diffusion inside the tunnel when the bottom of a metro train was on fire and to compare the effect of longitudinal ventilation modes on the smoke motion when the burning train stopped. Research results show that the slipstream curves around the train obtained by numerical simulation are consistent with experimental data. When the train decelerates, the smoke flow first extends to the tail of the train. With the decrease of the train's speed, the smoke flow diffuses to the head of the train. After the train stops, the slipstream around the train formed in the process of train operation plays a leading role in the smoke diffusion in the tunnel. The smoke flow quickly diffuses to the domain in front of the train. After forward mechanical ventilation is provided, the smoke flow inside the tunnel continues to diffuse downstream. When reverse mechanical ventilation operates, the smoke in front of the train flows back rapidly and diffuses to the rear of the train.

Impact of Village-based Health Education of Tobacco Control on the Current Smoking Rate in Chinese Rural Areas

The number of smokers in Chinese rural areas is more than 200 million, which is twice that in cities. It is very significant to carry out tobacco control interventions in rural areas. We performed this community intervention study to evaluate the efficacy of village-based health education of tobacco control on the male current smoking rate in rural areas. The population of this study was the males above 15 years old from 6 villages in rural areas. The villages were randomly assigned to intervention group or control group（3 villages in each group）. Self-designed smoking questionnaire was applied. The intervention group received the village-based health education of tobacco control for one year. The primary outcome measurement was the male current smoking rate. In the baseline investigation, completed surveys were returned by 814 male residents from the control group and 831 male residents from the intervention group. The male current smoking rate in the control group and the intervention group was 61.2% and 58.5%, respectively, before intervention. There was no significant difference between these two groups（P〉0.05）. After one-year intervention, the current smoking rate in the intervention group（51.2%） was significantly lower than that in the control group（62.8%）（P〈0.001）. Our study suggested that the village-based health education of tobacco control was effective in lowering the male current smoking rate in rural areas, which could be a suitable and feasible way for tobacco control in the Chinese rural areas.

Discussion on the Construction of Anti-smoke Construction Technology in Super High-rise Buildings

In recent years with the increasing number of super high-rise buildings and the ever-expanding scale the anti-smoke construction technology has attracted more and more attention.Based on this situation,this paper analyzes the smoke control technology of super high-rise buildings.The paper analyzes the importance of the application of anti-smoke construction technology in super high-rise buildings,analyzes the problems in the construction of smoke control and super high-rise buildings.The anti-smoke construction technology was studied and I hope that it can benefit the application of anti-smoke construction technology in high-rise buildings.

A Decision Tree Approach for Predicting Smokers’Quit Intentions

This paper presents a decision tree approach for predicting smokers＇ quit intentions using the data from the International Tobacco Control Four Country Survey. Three rule-based classification models are generated from three data sets using attributes in relation to demographics, warning labels, and smokers＇ beliefs. Both demographic attributes and warning label attributes are important in predicting smokers＇ quit intentions. The model＇s ability to predict smokers＇ quit intentions is enhanced, if the attributes regarding smokers＇ internal motivation and beliefs about quitting are included.

The case for gender considerate tobacco control policies in Albania

Background:Tobacco use is a serious health concern in Albania.While the prevalence of tobacco smoking has traditionally been higher for men,the increasing prevalence of smoking for women is becoming a concern.The 2007 Tobacco Control policy mandated smoke-free indoor spaces,banned various forms of tobacco advertising,required written health warnings on packaging and levied excise taxes on cigarette sales.Since smoking behavior varies among different demographic groups,each group’s response to a uniform policy will differ,blunting the effectiveness of these efforts as a result.This study examines various socioeconomic,demographic and behavioral factors affecting both the likelihood and frequency of smoking in Albanian households in order to provide insights on targeting various populations more effectively.Methods:The study utilizes data from Albanian 2008-09 and 2017-18 Demographic and Health Surveys consisting of adults aged 15-49 years.The outcome variable includes respondents’current tobacco smoking behaviour and its frequency.The exposure variables include respondents’sociodemographic and lifestyle characteristics.We use a two-level random intercept model with the two-stage residual inclusion estimation method to determine the association between outcome and exposure variables.By including a time variable,we capture the change in smoking behavior during the 2009-2018 period.We also extend the analysis by assessing the differential influence of gender on the likelihood of smoking,both by income quintiles and education.Results:The results suggest that the likelihood of smoking decreased by 23%in 2017-18 compared to 2008-09,after controlling for various socioeconomic and demographic factors.Tobacco smoking is also found to be linked to alcohol consumption,with binge drinkers 59%more likely to smoke tobacco compared to moderate drinkers.We also found significant inter-quintile and inter-educational differences in smoking practices within each gender category.While the likelihood of tobacco smoking decreases with increasing wealth and educational attainment among men,the opposite(for wealth)or more involved(for educational attainment)patterns are true among women.Conclusions:To further enhance the effectiveness of the current Tobacco Control policy,the Government of Albania should target various demographic groups(such as poor males,rich and educated females)in a differentiated fashion.

PEST Analysis of the Development and Challenge of Macao’s 2015 Tobacco Control Law

The Legislative Assembly of the Macao Special Administrative Region passed the 2015 Tobacco Control Laws on July 10, 2015, stimulating a heated discussion and debate in society. In this study, a content analysis of news coverage appearing in Macao Daily between July 1, 2015 and December 31, 2015 was conducted. It also applied PEST method to carry out detailed analysis of the public’s opinions, aiming at gaining a better understanding of the current situation of tobacco control work in Macao and the challenges lay ahead. Moreover, we use KAP （Knowledge-Attitude-Practice） framework to propose further enhancement and improvement of government’s tobacco control work.

Effect of Genetic Polymorphism of CYP2A6 on Individual Susceptibility to Colorectal Tumors in Japanese Smokers

Tobacco smoking is a risk factor for colorectal cancer and adenomas. To clarify the effect of genetic factors on the risk for tobacco-related colorectal tumors in a Japanese population, we performed a case-control study on 300 patients with two or more tumors and 181 healthy controls;all were genotyped for CYP2A6*4, CYP2A6*7 and CYP2A6*9. Cigarette smoking increased colorectal tumor risk (trend-test P ). Current smokers plus ex-smokers (ever-smokers) with the CYP2A6*4/*4 genotype (whole gene deletion) showed the lowest risk among smokers [odds ratio (OR), 0.17;95% confidence interval (CI), 0.05 - 0.62 compared to ever-smokers with the wild-type CYP2A6*1/*1]. When the participants were classified into four phenotype groups based on estimated CYP2A6 activity [i.e., normal (*1/*1), intermediate (heterozygotes for the *1 and a variant allele), slow (heterozygotes and homozygotes for variant alleles except for *4/*4) and poor (*4/*4)], the ORs (95% CIs) in ever-smokers of the normal, intermediate, slow and poor groups were 6.75 (2.73 - 16.76), 4.59 (2.10 - 10.06), 3.89 (1.69 - 8.95) and 1.17 (0.31 - 4.40), respectively, compared with never-smokers with normal CYP2A6 activity. The susceptibility to colorectal tumors was dependent on the predicted phenotype among ever-smokers (trend-test P = 0.015), but not among never-smokers (trend-test P = 0.47). Stratifying the subjects with respect to cumulative tobacco exposure and estimated CYP2A6 activity, we found the highest risk of colorectal tumors in subjects with higher CYP2A6 activity and higher cumulative tobacco exposure (trend-test P = 0.000023);the lowest risk was found in subjects with the lowest estimated CYP2A6 activity independent of tobacco exposure (trend-test P = 1.00). These results suggest that the gene-environment interaction (i.e. , the CYP2A6-smoking interaction) strongly affects the individual susceptibility to tobacco-related colorectal tumors.

城市轨道交通超长隧道双车追踪模式下火灾烟气控制与人员安全疏散研究

[目的]城市轨道交通发车间隔一般较短,在超长隧道内会出现同方向行驶两列列车的情况,一旦发生火灾容易造成重大财产损失和人员伤亡,因此需对超长隧道双车追踪模式下的火灾烟气蔓延规律和人员安全疏散策略进行研究。[方法]采用FDS(火灾动力学模拟)软件和Path-finder软件,建立超长隧道火灾模型和人员安全疏散模型,对双车追踪模式下的火灾烟气蔓延规律,以及人员疏散进行仿真分析。[结果及结论]双车追踪模式下,前车尾部着火,通过临界风速纵向通风可保证前车火灾安全;火源下游烟气前锋的蔓延速度为3.20 m/s,至600 s时烟气蔓延至后车,620 s时烟气可完全覆盖后车;烟气温度沿隧道纵向衰减很快,且温度衰减符合双指数模型规律。双车追踪模式下,减小联络通道间距可减少人员疏散总时间,对人员疏散时离开列车的时间影响不大;开启列车端门和疏散平台一侧车门,可显著减少人员疏散时间。在超长隧道双车追踪的最不利火灾场景下,人员疏散存在困难,可通过减小联络通道间距保障人员疏散安全。

扁平大空间船舶火灾烟气控制试验研究

为有效控制扁平大空间船舶火灾烟气蔓延,研究大尺度火灾过程中的油池质量损失速率、舱室温度分布、隔热效率和烟气控制效果。利用尺寸为30 m×24 m×2.3 m的模拟舱,在0.35、0.55和0.70 m等3种不同挡烟垂壁高度和机械通风条件下开展试验。结果表明:挡烟垂壁高度增加,油池质量损失速率峰值减小;挡烟垂壁高度对舱室上层烟气温度的影响比对下层气体温度的影响更明显,1.4 m以上空间温度峰值明显下降,而1.4 m以下空间温度峰值无明显变化。顶棚平均温度和隔热效率随挡烟垂壁高度增加而下降。随挡烟垂壁高度增加,火源区与非火源区同时控烟模式隔热效率从28.2%提升至50.8%,火源区单独控烟模式隔热效率从29.4%提升至54.7%。

基于区段的地下空间环路通风排烟设计方法

为实现多匝道、多地块、内部空间复杂的地下空间环路烟气控制,提出一种区段式排烟方法:将地下空间环路与地块通过防火门分隔,形成独立的构筑物,结合隧道结构,确定风机房位置,划分区段,使烟气在一定区域内排出。以滨江地下环路为例,在隧道主线上均匀布置6个排烟风机房,并以此为节点,将隧道划分为8个区段。当火灾发生时,开启所在区段两端的风机进行排烟。由于各区段不设置固定分隔,整个风道是贯通的,因而各个风机房里的风机可互相作为备用排烟风机,以降低成本。采用数值模拟软件建立模型,对排烟口开启数量和间距进行模拟,确定排烟量为90 m^(3)/s、排烟口间距为30 m、开启8个排烟口的排烟方案。从人员疏散环境以及排烟效率对典型区段进行分析,结果表明:烟气控制在一定的范围内,人员疏散环境安全,排烟效率达到90%,证明方案合理可行。

矿井带式输送机火灾烟流特性及其预警防控综述

为有效防控煤矿井下带式输送机火灾事故,保障煤矿工作人员的生命财产安全,系统分析矿井带式输送机火灾的起火原因、燃烧特性、烟流特性、监测预警技术及防治措施,并基于当前研究现状提出展望。结果表明:引发带式输送机火灾的主要原因是摩擦温升、电气设备故障及明火;研究带式输送机火灾燃烧和烟流特性采用的巷道火灾模型及数值模拟相关参数具有一定局限性,需综合考虑运输巷道实际工况及环境等参数;国内虽有针对带式输送机火灾的监测预警系统,但其尚有不足,需引入5G、大数据及人工智能等新兴技术予以完善,并结合硬件探测及人员管理等方面,健全煤矿带式输送机火灾防治体系,进而全面推动煤矿安全智能化建设。

特长跨海公路隧道竖井组协同风量与防排烟设计研究

青岛第二海底隧道首创性地在两管隧道排烟道上纵向间隔设置联络烟道,将南北线烟道联通,以提高通风效率。因此,亟须明确不同竖井组协同风量对联络烟道风量的影响规律,确定最佳的南北线风量配比和两线竖井风量配比。对比不同风量配比对联络烟道风速、利用率的影响,结果表明,南北线风量配比的变化对联络烟道风速的影响较小,但能一定程度上缓解南北两线隧道因两侧风量相同而相互抽吸导致的隧道中心位置风速过低的情况。两线的风量配比对联络烟道风速有较大影响,当两线竖井风量配比由5∶5逐渐变化到2∶8时,联络烟道中间排烟道平均风速由0.89 m/s提升到1.18 m/s,提升幅度约为32.58%,联络烟道利用率由41.18%提升到54.75%,推荐使用不均衡的两线竖井风量配比模式,两线竖井风量配比为2∶8时具有最高的联络烟道利用率。并采用缩尺寸模型试验,验证了该风量配比设计的合理性。

酒糟锅炉周期性冒黑烟的原因分析及控制研究

针对酒糟锅炉在调试过程中出现的烟囱周期性冒黑烟问题,首先对锅炉燃料成分、酒糟燃烧特性、锅炉结构、锅炉燃烧方式及烟气流程进行了介绍;然后分析了黑烟的产生及危害;紧接着分析了锅炉烟囱周期性冒黑烟的原因,并在此基础上对螺旋给料机进行了改造,对湿式除尘器进行了更换;最后经过效果检查,锅炉烟囱周期性冒黑烟的问题得到了有效解决,这为类似锅炉技术改造提供了参考。

高大宴会厅防排烟系统改造效果研究

高大空间防排烟系统的安全性和可靠性非常重要。宁波市某宾馆防排烟系统需要改造,其中宴会厅为高大空间。针对宴会厅的防排烟系统改造设计方案进行数值模拟研究,首先根据现行规范计算排烟量,设计排烟口,计算排烟量比原设计排烟量减少41%,排烟风口减少1个;然后采用Pyrosim软件模拟改造前后烟气扩散情况,监测宴会厅内能见度、温度和CO浓度。模拟结果表明:安全疏散时间内,改造后的烟气一直保持在距地面5m以上,人眼特征高度处的温度最高降低3℃,建筑顶棚温度最高降低20℃,最小清晰高度处的CO浓度最大可降低0.6PPM。改造后的防排烟系统方案更安全可靠。