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2D Droplet Size and Velocity Analysis of a Fan-Shaped Spray Using Ilids Method
( Masato Yamada ),( Chang Seong Ryu ),( Yasuo Moryoshi ),( Ryo Uchida ),( Masato Kubota ),( Masahide Takagi ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-
DI (direct injection) systems have been studied to improve thermal efficiency of gasoline engines. The analysis of spray behavior is important to examine the combustion characteristics of DI gasoline engines because fuel-air mixture formation is controlled by spray characteristics and gas motion. In this study, the characteristics of a fan-shaped spray, such as the droplet size, its velocity and the droplet-size distribution were simultaneously measured on a 2D plane by using an improved ILIDS (Interferometric Laser Imaging for Droplet Sizing) method. As a result, interesting relationships between the droplets diameter and the velocity were found. In addition, numerical analysis of a fan-shaped spray was conducted and the results were compared to the measured results. In numerical analysis, the nozzle internal flow was predicted by using VOF (Volume of Fluid) model that can simulate the two-phase flow inside the nozzle to give the liquid film formation process outside the nozzle. Using the results of VOF model for the initial conditions, numerical analysis of the spray by DDM (Discrete Droplet Model) was carried out to examine the droplets breakup process. As a result, SMD has become small with going away from the nozzle center section that is the same tendency as the experiment.
Management of Flood Waste in Small and Medium Scale Asian Cities in Tropical Region
( Tomonori Ishigaki ),( Kosuke Kawai ),( Rieko Kubota ),( Komsilp Wangyao ),( Pham Khac Lieu ),( Sirintornthep Towprayoon ),( Chart Chiemchaisri ),( Masato Yamada ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-
This study reports on the challenges to a model of resilient and adaptable SWM against flood in Asian tropical/pluvial countries, in order to adapt to frequent flood events that would be influenced by climate change. Collapse of Solid waste management by sudden natural disasters will directly lead to collapse of city. Here we have summarized some cases of flood waste handlings in tropical Asian cities that were attacked by flood disasters recently. Mega-scale city like Bangkok should have enough capacity to handle of flood waste though the inundation of some part of capital must be a considerable worst situation. In contrast, small and medium scale cities easily lost their ability to administrate under flooding situation if the prepared ness was not sufficient. Situation of "vulnerable" against to flood must be improved for quick recovery from disaster, and waste management systems is also expected to be more resilient. The goal of this study is to draw a scheme of guidance to improve or upgrade the solid waste management system in middle or small scale cities that leads the cities to be resilient against to flood.
Current State of Construction and Demolition Waste Management in Vietnam
( Han Hoang ),( Tomonori Ishigaki ),( Rieko Kubota ),( Masato Yamada ),( Ken Kawamoto ),( Giang Nguyen ),( Kien Tong ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 한국폐기물자원순환학회 심포지움 Vol.2019 No.1
The construction industry plays an important role in the Vietnamese economy. However, a significant amount of CDW has been generated in association with increasing growth of this industry. CDW accounts for 10-12% of total municipal solid waste generated, equaling about 9,000 tonnes/day in Vietnam (MONRE, 2011). Despite rising CDW related issues, current CDW management activities are not well documented. To date, there are no official statistics of and limited studies on CDW generation and handling practices. To fill this information gap, the overarching aim of this study is to provide better understanding of the overall situation of CDW in Vietnam through: (1) estimating CDW generation rates and CDW composition, and (2) identifying CDW flows. 15 building construction and demolition sites were surveyed during the course of two months. The sites were selected so that they were located in diverse districts in Hanoi and involved different contractors and developers. Three pilot site visits were implemented to identify shortcomings of and revise survey methodology. The following three methods were applied to collect data: ㆍ CDW quantification: waste amount was determined through applying the method developed by Lau, Whyte, and Law (2008). Of which, CDW was categorised and measured according to its layout in order to identify its volume. CDW volume was converted into CDW weight afterwards. ㆍ CDW composition: Image analysis was utilised to identify CDW compositions. Photos of waste stockpiles/ piles were captured and superimposed by 11x11 dot grids to determine waste components. The sum of dots indicates each waste component’s proportion in the stockpiles/piles. ㆍ CDW flow: Face-to-face interviews using semi-structured questionnaires were conducted with site managers and contractors to identify final destinations of CDW and actors involved in CDW flows. Data collected identified that brick and concrete are the main wastes generated in demolition activities whilst soil is dominant in construction ones (Figure 1 and 2). Given that surveyed construction sites are significantly larger than other sites, soil has the most significant share (64.9%) in total waste composition, followed by concrete (20.2%), brick (5.9%) and wood (3.3%). The interviews on the CDW flow revealed that about 33% of CDW is reused and recycled through backfilling at other construction sites (concrete, brick, etc.) or sold to recyclers (wood, metal, plastics, etc.). The rest is disposed either at official CDW landfills (34%) or at unknown/unofficial dumping areas (33%). Current CDW handling practices is solely profit-driven with very limited management of the government. The identified WGRs and composition are beneficial to future studies that estimate the amount of CDW generated nationwide. The study findings on nature of current CDW management system are hoped to lead to better plans or business strategy development for CDW recycling market in Vietnam.