Procedia Engineering最新文献

Experiments were conducted in a fire test room to investigate soot particle and burning behavior of n-heptane/toluene mixtures blended by liquids in different mixing ratio and different purity. Analytical reagent n-heptane (AR, purity ≥ 99.5 %), chemically pure n-heptane (CP, purity ≥ 97 %) and toluene (purity ≥ 99.5 %) were selected to prepare four kinds of mixtures, mixing by volume and by mass were two modes available. Extinction coefficient of smoke was obtained by extinction meter on the room ceiling. Size distribution of soot particles was measured by fast particulate spectrometer DMS500, then count median diameter (CMD) and geometric standard deviation of diameter (GSD) were calculated. Mass loss curve and temperature profile were measured by electronic balance and thermocouples, respectively. Experimental results revealed that even small difference in the incorporation of toluene, such as mixed by volume and mixed by mass, had significant influences on smoke extinction and CMD. When fuels were mixed in a same mass ratio, slight gap in purities could also affect smoke extinction. Thus fuels mixed by mass could not be employed as test fire, while CP n-heptane could be selected to prepare fuels of test fire based on our preliminary results. As for burning behavior, temperature profiles were almost identical for all mixtures, mass loss curves also had good consistencies.

The design of parts and structures in the vehicle development process is highly influenced by strength and stiffness requirements. Under cyclic loading a change in the local stiffness of joints can be observed which motivates analyses in order to tackle stiffness changes in structures. The fatigue and stiffness behaviour has been obtained for several joining techniques and material combinations: spot and seam welds, remote laser welds and high velocity bolting for steel and/or aluminium partner sheets. Specimens under shear and peel loading as well as hat profiles under torsion have been tested under constant amplitude loading. Quasi-static tests and micrographic evaluations have been conducted in order to determine material parameters and the setup of FE models. Online stiffness measurements during fatigue life have been performed. In this paper an approach to describe degradation in specimens representing a joint detail is presented. The stiffness degradation curves for the various joining techniques are compared and a numerical description of the stiffness degradation behaviour for further simulations is derived. The concept of simulating stiffness changes in conventional joining techniques is introduced. First numerical analyses of stiffness changes in spot welded specimens are presented. Several sensitivity analyses, e.g. with regard to R-ratio or loading amplitude, are performed in order to check the numerical stability of the implemented method.

Chiang Mai is the second largest city in Thailand, and a popular tourist destination with around 7 million tourists per year. It situated in the Northern region, about 700 kilometers north of Bangkok. Eighty per cent of the area is mountains and 70 per cent of the land is forest area. The topography and the rapid and diverse socio-economic structure of the province have affected not only land use change and economic activities but also the quality of its environment. Chiang Mai has been facing the problem of haze pollution over the past decade, particular during the dry season from February to May. With the exposure and vulnerability of the area, this problem occurred annually and has affected Chiang Mai tremendously. This research aims to investigate the building resilience of Chiang Mai through various sectors (academic, government, private, and local communities) during the past 10 years, between 2007 and 2016. The perception and coping strategies of the villagers and communities in the most affected areas are also examined. Primary data were collected by focus group interviews with people from government, private, academic, and civil society sectors, and interviews with 400 villagers from the most affected areas in San Pa Tong, Doi Lo, Chom Thong, and Hot Districts. Results show the interesting progress in resilience of the population of Chiang Mai province over the past 10 years, from response to recovery, mitigation, and preparation for long term sustainability. It indicates that the road to resilience has faced with many difficulties, particularly at the community/village level where most of the villagers lack the opportunity to participate with the higher levels.

Kolonnawa was one of the main cities which had been affected by heavy floods in year 2016 which made residents of that area refugees for a few weeks. This study was aimed at examining the coping strategies identified and used by the victims at individual and community levels. Since social work perspective is used by the researcher to carry out the research, sub objectives of the study were to measure the already used coping strategies within a social work perspective and to identify differences between community based coping strategies and state interventions. The research problem addressed the coping strategies identified and used by victims of flood disaster in Kolonnawa as individuals and as a community. The research questions used to gather data and information were: (1) what were the coping strategies identified by each victimized household?; (2) what were the steps taken at the individual level?; (3) what were the steps taken at the community level?; (4) what else could have been used as coping strategies? and (5) what would be the role of the social worker in such a post disaster context. Since the study used a qualitative approach, data and information were collected from 15 heavily affected households in Egoda Kolonnawa and Megoda Kolonnawa where convenience sampling method was used as the sampling method. 30 semi-structured interviews were conducted with selected 15 households which included affected people from diverse backgrounds ranging from gender and age. Thematic analysis method was used as data analysis method. The main argument developed through the data and information gathered in this study was that there were different coping strategies identified and used by flood victims in reactive and recovery phases during which appropriate and effective state interventions were absent and it resulted in victims becoming dependents due to loss of material possessions where empowerment and resilience within affected community were also not present as coping strategies which should have been considered through a prism of Social Work.

Pakistan has undergone multiple geological and climate-related disasters in recent years. This includes the devastating 2005 Kashmir earthquake, and yearly countrywide flooding since 2010 till present. The recurrence of such disasters has led to the establishment of national and provincial disaster management institutions, which worked towards the formulation of national disaster management plan. As a result, Pakistan’s National Disaster Management Plan (NDMP) was approved in 2012. This paper provides a review of Pakistan’s National Multi-Hazard Early Warning System Plan (NMH-EWS-P) that is part of the overall NDMP, approved prior to the introduction of the 2015-2030 Sendai Framework for Disaster Risk Reduction (SFDRR). The research identifies various aspects of the national plan, which require amendments in the light of the Sendai Framework. The implementation of the NMH-EWS-P is reviewed by the case study of the province of Punjab, where the Punjab Disaster Management Authority (PDMA) is responsible for the implementation of the national plan at provincial level. With the analysis of Early Warning Systems against natural disasters, as implemented by the PDMA, the gaps and shortcomings of the prevailing practice are identified. Furthermore, this research also aims to propose practical solutions and recommendations for improvement, and better alignment of the prevailing Early Warning System with that of the Sendai Framework.

In order to obtain the failure characteristics of pipe surface under the shock wave action of gas explosion, the physical and mathematical model of gas explosion in pipe were established by LS-DYNA software, and the shock failure characteristics of pipe surface with different radii under gas explosion were simulated, the radius is 0.4 m, 0.6 m, 0.8 m and 1.0 m, respectively. Results showed that with the increase of the radius, the duration of the pressure "platform" in the measuring point A and B is obviously shortened, fluctuation range produced by the pressure curves in measuring points C, D, E and F change less, but their fluctuation time is shortened. The explosion pressure increases and the failure degree increases with increase of the radius. Finally, the influence of scale effect of gas explosion and its propagation process on gas explosion propagation parameters is obtained. The research results have some guiding effects on gas explosion and disaster prevention.