Procedia Engineering最新文献

Bangladesh has often been considered as the land of extremes in terms of natural processes. The statement is justified by the presence of world’s largest delta, one of the largest river systems carrying a huge amount of water and sediment discharge as well as prevalence of a number of natural hazards. These characteristics make the region very dynamic and sensitive to changes. Bangladesh is one of the most densely populated countries in the world and human development activities to accommodate the large population have caused major disruptions to the dynamics of the natural system. The study focuses on such a case where anthropogenic activities, such as polderization, dam construction etc. have disrupted the natural land building process and have caused persistent waterlogging in the southwest region of Bangladesh. The rivers in the region are naturally characterized by active deposition of sediment in riverbed causing reduced drainage capacity. Moreover, construction of coastal polders that de-linked the flood plains from the rivers, and diminished upstream flow during the dry season deteriorated the sedimentation problem in the region. The study delineates different hydrological parameters and characteristics of the deposited sediments along with identification of social vulnerabilities. The investigated hydrological and sedimentological characteristics refer to the existing sediment management as well as provide a framework for the future development works in the pre-identified TRM sites. Based on the findings, the suitability of Inclusive and Adaptive Tidal River Management (TRM++) technique was assessed.

HNBR (Hydrogenated Nitrile Butadiene Rubber) is a synthetic rubber with good resistance to heat and oil products; due its properties, HNBR is utilized in high-demanding applications in oil exploration, aerospace, automotive, and other industries. However, compared to other industrial rubbers, there are only few published studies on the fatigue behavior of HNBR. Moreover, it is important to understand how fatigue resistance is affected by the formulation of HNBR, specifically by the content of acrylonitrile (ACN) monomers and percentage of hydrogenation (number of saturated bonds). First, fatigue experiments are carried out for unaged samples at 120°C, which is the median operating temperature for these HNBR blends. Five HNBR blends are tested with various contents of acrylonitrile and various percentages of hydrogenation. Afterwards, testing is carried out one of the blend, i.e. HNBR with 36% ACN and 96% hydrogenation at 150°C for simultaneous ageing and fatigue conditions. For fatigue life experiments, the Wöhler curve is built according to a novel experimental approach of true stress control for four loading levels and R=0 loading ratio. Preliminary results with thermal ageing are subsequently presented.

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.

The concept of ocean current and fishery industry is expressed from the architectural design in using crossed exterior corridors to perform ocean current. The contrast between modern and obsolete is represented by the staggered interior design and antiquated building structure of the heritage, which is used to be North Thermal Power Plant. It is therefore partial areas which cannot fulfill the article 79-2 of Building Design and Construction Regulation mandated by Taiwan government that stipulate the requirement of any void space over 3 floors. Requirement of smoke extraction system and smoke curtain is also exempted from article 188 of Standard for Installation of Fire Safety Equipment Based on Use and Occupancy. Performance-based design is adopted by fire engineering approach as an alternative. This project passed the expert panel review of fire engineering strategies and smoke management assessment. At the stage of construction by auditing and reviewing, full-scale hot smoke test was conducted due to the safety consideration raised by local government. The results of tests are significantly different from the simulation modelling and smoke management report approved by National Fire Agency, Ministry of Interior. Visibility in partial areas is around 10 m which is not regarded as a tenable condition. After the improvement of smoke management, the study of full-scale hot smoke tests and computational simulated results are carried out. Acceptance criteria, usually smoke temperature, smoke layer height and visibility in Taiwan, are reached regardless of differences between FDS model and on-site full-scale tested values. This project provided design considerations to designer during design process, including the environmental differences of internal and external building, local weather impact, and grid size used in FDS model. The limitation and discrepancy of chosen software among different versions should be understood so that simulation results would more fit the realistic circumstances.

This works aims at identifying the influence of surface integrity parameters on fatigue life of a 15-5PH. The effect of residual stress profile, surface roughness and microstructure are investigated. Various cutting and superfinishing processes (turning, ball burnishing and belt finishing) are used so as to reach various engineered surface integrities and as a consequence to highlight the influence of each surface integrity parameter. Rotary-bending tests have been carried out on samples to determine the average fatigue strength at 2 million cycles. It is shown that the influence of a deep compressive sublayer is by far more important than the ones of surface roughness or microstructure. The so-called ‘white-layer’ brings also a slight improvement of fatigue resistance.

The Asian countries (Sri Lanka, Thailand, Bangladesh) in the ASCENT project have an unequally spread out and restricted RTD ability. An interactive and cooperative university - industry partnership can increase the quality of life and reduce the risk of disaster. Here the fields where universities consider the involvement of industry are recognized (e.g., fundamental and applied research, development, production life cycle and such). There is a recognized need for the private sector to engage the research community in the context of disaster resilience research to tackle disaster risk. The definition of “industry” in this research is deliberately vague to allow exploration of what useful collaborations “industries” can develop with universities for disaster management research (here collaborations mean different life cycle interactions). There is the need for an integrated multiple criteria decision analysis to mitigate the effects of disaster on the built environment at three levels: the micro (research and innovation performance, transfer and absorptive capacity, technology development), meso (institutional arrangements, communication network, local and indigenous rules) and macro (supply and demand, regulations, financing, taxes, culture, traditions, market, climate, political, demographic, technology) levels. Disaster management involves numerous aspects for consideration in addition to making economic, political and legal/regulatory decisions. These must include social, cultural, ethical, psychological, educational, environmental, provisional, technological, technical, organizational and managerial aspects. This research produced a model and a system for integrated analysis of the iterative life cycle of university-industry partnerships. The model and the system make it possible to perform multi-variant design and multiple criteria assessment of alternative university-industry partnership life cycles, calculate their market and investment value, conduct online negotiations, and select options that offer the best efficiency.

In the present work, the Fatemi-Socie approach is adopted in order to analyze the fatigue endurance of welded joints under multiaxial loads. This critical plane criterion has already been successfully applied to plain or notched components, however, it is not spread in the assessment of welded joints, yet. This work is focused on the practical implementation issues related to this particular application, which has not been discussed in the literature. The described procedure is adopted for the assessment of one hundred experimental tests and some preliminary results are shown. The specimen under investigation is a pipe-to-plate fillet joint made out of structural steel (S355JR). The tests were performed under both uniaxial and multiaxial, i.e. combined in-phase and out-of-phase bending and torsion, load conditions with a constant amplitude at the laboratories of the University of Pisa, Italy.

This study has demonstrated the preparation of NaOH-FBC and investigated its potential application as an adsorbent to remove MB from aqueous solution. Adsorption Experiments of MB removal were carried out based on the parameters of initial pH, initial MB concentration, temperature and contact time. Results showed that the specific surface area of the NaOH-FBC reached up to 61.13m²/g. The experimental adsorption data were analyzed with Langmuir and Freundlich isotherm models. The kinetic adsorption models were also studied. By fitting the Langmuir adsorption isotherm model, the q_max of the NaOH-FBC was highly achieved as 605.82±9.09 mg/g, compared to 70.42±1.34 mg/g produced by the untreated FBC. The MB adsorption process using the untreated FBC was a non-spontaneous and endothermic process, which was well fitted with the pseudo-first-order kinetic model and Freundlich adsorption isotherm model. However, the MB adsorption process of the NaOH-FBC was a spontaneous and endothermic process, which was in accordance with the pseudo-second-order kinetic model and Freundlich adsorption isotherm model. Furthermore, with the increase of pH, temperature and contact time, the adsorption capacity of MB onto the FBC and NaOH-FBC were both increased. The adsorption results suggest the efficiency and potential of NaOH-FBC as a MB adsorbent.

Dhaka is one of the most vulnerable cities of the world to the adverse effects of climate change and variables. Children of Dhaka are the most vulnerable group of people to any crucial change in weather pattern or climate; i.e. heat wave and heavy precipitation. However, little research has been conducted with children on their perception of climate change which is important for developing coping strategies - resilience to inform urban development and planning policies for the city. This mixed method research conducted a cross-sectional survey on children of three schools in Dhaka. Analysis of the survey shows that socio-economic and educational background of the children defines their access to infrastructure, services and facilities; thus frame their experience and perception of vulnerabilities. Children have clear perception on the changes in temperature and rainfall in Dhaka. Although they feel more comfortable with heavy precipitation than increased heat, yet both the conditions affect their physiological health and daily activities negatively. The actions they suggested to cope with the negative impacts of climate change are mostly reactive than anticipatory in nature illustrating dependency on adults to increase their adaptive capacity. However their concern for every-day stress and well-being affected by the deteriorating weather conditions illustrate a sense of anxiety among them. The children also identified a few coping strategies - resilience to adapt to the impacts of extreme weather events that may inform to develop a comprehensive urban design guideline and planning policy for Dhaka.