Procedia Engineering最新文献

This study focused on the Disaster Risk Reduction and Management of Tarlac City. The city disaster risk reduction and management structure; the identified hazards and evacuation areas; the Tarlac City DRRM Plan in four thematic areas as identified in the NDRRM Plan; the CDRRMO vehicles, equipment, and resources; and the community based responders are presented in this paper.

The following conclusions are reached based on the gathered information and data. The CDRRMC and CDRRMO are established and functioning as to their mandate, based on the certificate of recognition given by DILG to the City Government of Tarlac regarding disaster preparedness. The structure of the CDRRMO is approved by the city council but lacks funding for filling up the identified positions. The CDRRMO has a hazard map with identified barangays prone to flooding, lahar flow, and earthquake. The thematic action plans of the City Government are aligned with the Sendai Framework for Disaster Risk Reduction. This is evident in the list of programs and projects in their action plans. The existence of community based responders shows that the City Government is extending support to the barangay level by training local officials on how to respond in times of disaster.

To evaluate fire risk of typical liquid oils applied in nacelle of wind turbine, pyrolysis properties prior to combustion should be known. Pyrolysis properties of three kinds of typical oils of hydraulic oil, gearbox oil and transformer oil were studied by using Thermogravimetry (TG)- Differential Scanning Calorimetry (DSC) technique. Pyrolysis kinetics was analyzed. Apparent activation energy and pre-exponential factor were calculated by using Kissinger method. Results show that according to the TG-DSC analysis, for all three oils, the pyrolysis processes can be divided into three stages. The first stage is evaporation from room temperature to 140.1 °C (gearbox oil), 123.4 °C (transformer oil), and 144.1 °C (hydraulic oil). The second stage is the primary mass loss stage, corresponding temperature is in the range of 140.1–542.0 °C (gearbox oil), 123.4–294.1 °C (transformer oil), and 144.1–329.5 °C (hydraulic oil), among which the temperature of maximum heat mass loss rate of gearbox oil, transformer oil and hydraulic oil is 402.6, 220.1 and 262.6 °C. The third stage is the end of char oxidation and mass of residual char is kept constant, the temperature is higher than 542.0, 294.1, and 329.5 °C. Activation energies and pre-exponential factors were obtained by kinetic analysis, according to the pyrolysis kinetics analysis, the hydraulic oil is more prone to be pyrolyzed than gearbox oil and transformer oil and this provides a basis for judging the combustion characteristics of oil products by pyrolysis kinetic parameters in the future.

Due to the existence of the converging intersections and diverging intersections, the urban underground road of multi-point entry and exit can show complicated forms in the air flow rate and smoke movement in a comparison with the underground road with single-point entry and exit. In this paper, the strategies of original ventilating and exhausting smoke of a certain urban underground of multi-point entry and exit road were simulated and evaluated by using ventilation simulation software IDA RTV. The partial ventilation scheme where the number of fans was reduced was analyzed. The running strategy of fans in the tunnel under three conditions was determined. And the influence of the fans in ramp tunnel on the wind speed of main road was studied. Results indicate that when exhausting smoke in branch section, The mode of operation where jet fan in the section is fully operated is unreasonable, which would lead to excessive wind speed downstream of the shaft. The running of the ramp fan has a certain influence on the wind speed of the main tunnel. In the ventilation and smoke control design, the ramp position and the operating mode of the ramp fan should be fully considered. Operating fans downstream of the shaft reversely can exhaust smoke more effectively. The results provide the theoretical basis for the ventilation and exhaust design of other complicated underground roads.

Selective Laser Melting (SLM) and Electron Beam Melting (EBM) are powder bed fusion processing which allows to build-up parts by successive addition of layers using 3D-CAD models. Among the advantages, are the high degree of freedom for part design and the small loss of material, which explain the increase of Ti-6Al-4V parts obtained by these processes. However, Ti-6Al-4V parts produced by SLM and EBM contain defects (surface roughness, porosity, tensile residual stresses) which decrease significantly the High Cycle Fatigue (HCF) life. In order to minimize the porosity and tensile residual stresses, post-processing treatments like Hot Isostatic Pressing (HIP) and Stress Relieving are often conducted. But the modification of the surface roughness by machining is very costly and not always possible, especially for parts with complex design. The aim of this work is to evaluate the effect of the surface roughness and microstructure of Ti-6Al-4V parts produced by SLM and EBM on the HCF life. Five sets of specimens were tested in tension-compression (R=-1; f=120Hz): Hot-Rolled (reference); SLM HIP machined; SLM HIP As-Built; EBM HIP machined; EBM HIP As-Built. For each condition, microstructure characterization, observation of the fracture surface of broken specimens and surface analysis were carried out respectively by Optical Microscope (OM), Scanning Electron Microscope (SEM) and 3D optical profilometer. Results of fatigue testing show a significant decrease of the HCF life mainly due to the surface roughness. Along with experimental testing, numerical simulations using FEM were conducted using the surface scans obtained by profilometry. Based on extreme values statistics of the crossland equivalent stress averaged on a critical distance, a methodology is proposed to take into account the effect of the surface roughness on the HCF life.

Implant fixation via the use of acrylic bone cement is now a well-established practice in orthopaedics. Excellent long-term clinical results are evidenced in national joint registers based on over 5 decades of clinical experience. Increased life expectancies, patient BMI, together with the need to remain active in later life, are expected to put greater demands on the materials used in load bearing joint arthroplasty. Failure of bone cement and its interfaces with the implant and bone often leads to loosening, requiring revision surgery. This is a particularly invasive procedure, with lower long-term success rates compared to the primary procedure. To reduce the incidence of bone cement failure, it is necessary to understand the origins of failure in vivo. In the past, bulk failure of bone cement has been attributed to damage accumulation originating at pores. Advances in imaging technology now mean that we are able to observe cement microconstituents readily and identify crack-initiating defects more precisely as we attempt to understand origins of failure. The role of radiopacifier particles within the bone cement has not been examined extensively to date, and the present study demonstrates that this microconstituent could be in crack formation due in part to its ability to agglomerate and not bond with the surrounding matrix. To verify this hypothesis, explanted bone cement and laboratory tested bone cement are compared and correlations in failure mechanisms are discussed.

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.

The assessment of service life of composite thermo-structural parts is a primary issue for the aeronautic industry. To this end, a unified damage model for woven composites undergoing both static and fatigue loadings is presented here. Its specificity resides in its rate damage evolution law, which enables to predict the behaviour of the material under cyclic or random fatigue loadings.