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Effect of waste-to-energy via hydrothermal treatment on greenhouse gas emissions in Zimbabwe
( Andile B. Maqhuzu ),( Kunio Yoshikawa ),( Fumitake Takahashi ) 한국폐기물자원순환학회(구 한국폐기물학회) 2017 한국폐기물자원순환학회 심포지움 Vol.2017 No.1
Landfilling remains a significant source of greenhouse gas (GHG) emissions and a major contributor to total anthropogenic methane emissions leading to global warming. For developing nations, landfilling is by far the lowest cost disposal method and it is likely to remain a favourable option as harsh economic conditions will likely impede the adoption of more environmentally-friendly technologies. Hydrothermal treatment (HTT), a relatively cheap waste-to- energy option, has the potential to solve a growing share of problems caused by the unsanitary disposal of municipal waste (MSW) in Zimbabwe. Groundwater contamination due to unconfined leachate flow and GHG emissions from landfills can be reduced if MSW is redirected to HTT plants. The thermochemical process involves the charring of carbohydrate feedstock at a relatively low-temperature atmosphere (180°C-350°C) and high autogenous pressure (up to 2.4 MPa) using steam to produce hydrochar or biocoal which resembles lignite-coal in its composition and properties. There is, however, uncertainty in the quantity of waste generated and subsequent emissions. This is largely caused by the lack of reliable MSW data collection systems at a local and national level in developing nations. The aim of this study is therefore to determine the amount of landfilled MSW, its energy potential and total expected GHG emissions using risk analysis tools to account for this uncertainty. Palisade’s @Risk tool, an Excel spreadsheet plug-in, was used to quantify and characterize Zimbabwe’s MSW using reported values of Zimbabwe MSW characteristics, typical heating values, ultimate and proximate analysis of MSW components. Estimates of landfill gas (LFG) emissions were based on the Intergovernmental Panel on Climate Change (IPCC) methodology of a Zero-Order Model which assumes fairly steady LFG emissions with time. Waste age presumably has no effect on LFG production using this model. Instead of using static values for all parameters concerned, stochastic values and probability distributions were used supported by 100 000 Monte Carlo simulations. 2016 was chosen as the year for our analysis to determine the effect of HTT on GHG emissions. Simulation results, at a 90% confidence interval, indicate that 556-1452 Gg of MSW was generated by Zimbabwe’s urban population in 2016. This estimation also suggests that 400-1237 Ggwas collected and openly dumped in unsanitary landfills representing about 5.91-18.5 PJ of energy that was merely wasted by not extracting its value. The mean in total GHG emissions expected from this landfilled MSW as shown in Fig. 1 is about 869 Gg CO<sub>2e</sub> using the IPCC methodology. Assuming that up to 100% of this waste can be diverted to hydrothermal treatment for value addition, total GHG emissions can be reduced to a range of about 33-1151 Gg CO<sub>2e</sub> (at 90% confidence level) and a mean of about 435 Gg CO<sub>2e</sub>
( Andile B. Maqhuzu ),( Kunio Yoshikawa ),( Fumitake Takahashi ) 한국폐기물자원순환학회(구 한국폐기물학회) 2016 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2016 No.-
The quality of Municipal Solid Waste (MSW) management remains at a very low level in Zimbabwe. The challenges posed by inadequate and inappropriate tools for waste disposal are evident as Zimbabwe’s history is clouded by a string of fairly recent cholera and typhoid outbreaks. The urban areas are teeming with illegally dumped litter as cash-strapped local authorities are unable to collect the waste. An alternative strategy to prevent the problems associated with poor MSW disposal practices is needed. Waste management based on social, economic, and environmental conditions is necessary for the environment-friendly development of Zimbabwe. Electric power supply is also an important issue from the viewpoints of the economic growth and environmental protection. In Zimbabwe, where shortages in domestic coal production adversely affect electricity supply, a waste-to-energy technology can be a promising solution for waste related problems. The hydrothermal conversion of municipal solid wastes into green products has received much attention in recent years. The partial substitution of coal by hydrothermally treated MSW has been tested extensively and the optimum blend levels are well known. However, limited studies have looked at the application of this technology for power generation in developing countries at a national level. In Zimbabwe, where MSW collection and disposal is less developed, the feasibility of hydrothermal technology largely depends on the quantities and quality of waste that can be converted amongst other factors be they social or economic. The aim of this study is therefore to determine the potential maximum amount of collectable MSW that can be converted for co-burning with coal if the technology is implemented. A desk research approach was used to quantify and characterize Zimbabwe’s MSW. The qualitative analysis and quantification of the coal-alternative fuel produced by hydrothermal conversion of Zimbabwe MSW was predicted using a model. The model was developed using extensive experimental data in published works covering hydrothermal conversion, Zimbabwe MSW characteristics, typical heating values, ultimate and proximate analysis of MSW components. Coal consumption at Zimbabwe’s coal-fired power stations was estimated based on reported plant capacities and Zimbabwe coal chemistry. Results from the model were compared with other investigations to establish confidence in the approach. The preliminary findings indicate that the quantities of MSW and theoretical yield of coal-alternate fuel justify the possibility of utilizing hydrothermal technology. When all of the coal-alternate fuel produced from MSW is utilized in coal-fired power plants with dependable operation capacity, 14.8% of the coal will be substituted, which is less than maximum acceptable substitution ratio (20%). However, further investigations such as cost analysis, or social feasibility analysis still need to be conducted to provide a conclusive answer to the question on the applicability of this technology in Zimbabwe.
조원도구,木村雄吉,盧基德,高橋邦雄 國立統營水産專門大學 附設 水産科學硏究所 1990 수산과학연구소보고 Vol.2 No.-
The effects of side walls of a channel in which a two-dimensional model of the Weis-Fogh mechanism is equipped are experimentally investigated. The effects of the elasticity of the spring which controls the opening angle of the wing are also studied. The thrust and drag increase after setting the side walls, but the efficiency of propulsion decreases when the opening angle is small ; otherwise it increases. By controlling the opening angle with the spring, the efficiency increases substantially, and it is cycle of the wing motion in the channel.
Anti-emetic Principles of Alpinia katsumadai Hayata
Ye Yang,Kaoru Kinoshita,Kiyotaka Koyama,Kunio Takahashi,Takaaki Tai,Yoshiki Nunoura,Kazuo Watanabe 한국생약학회 1999 Natural Product Sciences Vol.5 No.1
Bioassay-guided fractionation of anti-emetic constituents of Alpiraia katsumadai Hayata was performed. Nine compounds including one novel compound, (3R,5S)-trans-3,5-dihydroxy-1,7-diphenyl-1-heptene (9) were isolated from it. Among these compounds, four diarylheptanoids, one sesquiterpenoid and one flavonoid showed anti-emetic activity on copper sulfate induced-emesis in young chicks.
A Ship Propulsion Using a Mechanism of Hovering Flight of Small Insects
TSUTAHARA, Michihisa,KIMURA, Takeyoshi,RO, Kideok,TAKAHASHI, Kunio 國立統營水産專門大學 附設 水産科學硏究所 1990 수산과학연구소보고 Vol.2 No.-
A mechanism of hovering flight of small insects which is called the Weis-Fogh mechanism is applied to ship propulsion. A model of the propulsion mechanism is proposed, and a model ship equipped with this propulsion mechanism was made. The model ship demonstrates that this mechanism works as a ship propulsion. The dynamic properties of the model are studied experimentally, and the effects of the side walls and a control of the opening angle of the wing and also an interaction of two wings are clarified. Propulsive efficiency is as high as 80%, and the wing moving velocity is low comparing with the advancing speed of the ship. A conceptual design is carried out.
Hiroshi Nakagawara,Kenji Yamao,Takuji Gotoda,Daiichiro Kikuta,Akinori Takei,Kunio Iwatsuka,Toshimi Takahashi,Masahiro Ogawa,Akihiro Henmi,Makio Kobayashi,Mitsuhiko Moriyama 소화기인터벤션의학회 2019 Gastrointestinal Intervention Vol.8 No.2
Background: Endoscopic-guided placement of metal stents for unresectable malignant hilar biliary obstruction (UMHBO) is performed using partial stent-in-stent or side-by-side (SBS) techniques. The latter involves placing sequential stents within the bile duct. Excessive dilation of the bile duct during stent placement can have serious effects on the surrounding organs.Methods: This study details seven cases of SBS placement of 8.0 mm metal stents for UMHBO. Histopathological examinations were performed to identify the effects on the bile duct and surrounding tissues.Results: The mean post-placement diameter of the bile ducts was 13.86 mm, and no compression necrosis or thrombi were observed in surrounding tissues. Cholangitis occurred in five cases, and death occurred as a result of cholecystitis in one case. Conclusion: The use of 8.0-mm stents for SBS is unlikely to have major negative effects on peribiliary tissues and blood vessels. However, post-placement cholecystitis can result in increased mortality; thus, gallbladder drainage should be considered.