scholarly journals An experimental study on premixed CNG/H2/CO2 mixture flames

2018 ◽  
Vol 8 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Ilker Yilmaz ◽  
Harun Yilmaz ◽  
Omer Cam

Abstract In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW). All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.

Energetika ◽  
2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Harun Yilmaz ◽  
Omer Cam ◽  
Ilker Yilmaz

Swirling flows increase combustion performance via favouring flame stability, pollutant emissions, and combustion intensity. The strength of a swirling flow is characterized by a parameter known as swirl number, which is highly related to the dh/do ratio. In this study, effects of the swirler dh/do ratio on combustion and emission characteristics of the synthetic gas flames of premixed 20%CNG/30%H2/30%CO/20%CO2 mixture were experimentally investigated in a laboratory-scale swirl stabilized combustor. For this purpose, twelve different swirl generators were designed and manufactured. dh/do ratios of these swirlers were set as 0.30 and 0.50, and the geometric swirl number was varied between the values of 0.4 and 1.4 (at 0.2 intervals). All experiments were conducted at a fuel-lean equivalence ratio (ϕ = 0.6), room temperature, and local atmospheric conditions of the city of Kayseri, Turkey. A data logger was utilized to plot axial and radial temperatures and NOx, CO, and CO2 profiles, which were exploited to assess combustion and emission performance. Results showed that the dh/do ratio had a non-monotonic effect on the behaviour of combustion and emission of the tested synthetic gas mixture. Depending on the swirl number, increments and decrements were observed in temperature and emission values.


2016 ◽  
Vol 1 (1) ◽  
pp. 1-15
Author(s):  
Frederich Oscar Lontoh

This research is titled " The influence of sermon, church music and church facilities on the level of attendance”. The purpose of research is to identify and analyze whether sermon, church music and church facilities have influence on the the level of attendance. The target population in this study is a Christian church members who live in the city of Surabaya.. Sample required is equal to 47 respondents. Through sampling stratified Random techniques.These influence was measured using Pearson correlation coefficient and multiple regression analysis, t-test and analysis of variance. Descriptive  analysis  were taken to analyze the level of attendance according to demographic groups.The hypothesis in this study are the sermon, church music and church facilities have positive and significant on the level of attendance. The results showed that collectively, there are positive and significant correlation among the sermon, church music and church facilities on the level of attendance  96,2%. It means that 96,2 % of level of attendance influenced by sermon, church music and church facilities and the other 28,9% by others. All of the variable partially have significant correlation to level of attendance.


2012 ◽  
Vol 5 (2) ◽  
pp. 109
Author(s):  
Besin Gaspar

This research deals with the development of  self concept of Hiroko as the main character in Namaku Hiroko by Nh. Dini and tries to identify how Hiroko is portrayed in the story, how she interacts with other characters and whether she is portrayed as a character dominated by ”I” element or  ”Me”  element seen  from sociological and cultural point of view. As a qualitative research in nature, the source of data in this research is the novel Namaku Hiroko (1967) and the data ara analyzed and presented deductively. The result of this analysis shows that in the novel, Hiroko as a fictional character is  portrayed as a girl whose personality  develops and changes drastically from ”Me”  to ”I”. When she was still in the village  l iving with her parents, she was portrayed as a obedient girl who was loyal to the parents, polite and acted in accordance with the social customs. In short, her personality was dominated by ”Me”  self concept. On the other hand, when she moved to the city (Kyoto), she was portrayed as a wild girl  no longer controlled by the social customs. She was  firm and determined totake decisions of  her won  for her future without considering what other people would say about her. She did not want to be treated as object. To put it in another way, her personality is more dominated by the ”I” self concept.


ARTic ◽  
2019 ◽  
Vol 4 ◽  
pp. 167-176
Author(s):  
Risti Puspita Sari Hunowu

This research is aimed at studying the Hunto Sultan Amay Mosque located in Gorontalo City. Hunto Sultan Amay Mosque is the oldest mosque in the city of Gorontalo The Hunto Sultan Amay Mosque was built as proof of Sultan Amay's love for a daughter and is a representation of Islam in Gorontalo. Researchers will investigate the visual form of the Hunto Sultan Amay Mosque which was originally like an ancient mosque in the archipelago. can be seen from the shape of the roof which initially used an overlapping roof and then converted into a dome as well as mosques in the world, we can be sure the Hunto Sultan Amay Mosque uses a dome roof after the arrival of Dutch Colonial. The researcher used a qualitative method by observing the existing form in detail from the building of the mosque with an aesthetic approach, reviewing objects and selecting the selected ornament giving a classification of the shapes, so that the section became a reference for the author as research material. Based on the analysis of this thesis, the form  of the Hunto Sultan Amay mosque as well as the mosques located in the archipelago and the existence of ornaments in the Hunto Sultan Amay Mosque as a decorative structure support the grandeur of a mosque. On the other hand, Hunto Mosque ornaments reveal a teaching. The form of a teaching is manifested in the form of motives and does not depict living beings in a realist or naturalist manner. the decorative forms of the Hunto Sultan Sultan Mosque in general tend to lead to a form of flora, geometric ornaments, and ornament of calligraphy dominated by the distinctive colors of Islam, namely gold, white, red, yellow and green.


Author(s):  
Thea Turkington

Landslides and flash floods result in many fatalities around the globe. Understanding what triggers these events is therefore vital, although how to approach this problem is not straight forward. After background information for the experiment and some guidelines, two options are presented to learn more about the triggers of debris flows: (A) using rainfall or (B) the atmospheric conditions. You can then choose the option that appears more useful and interesting to you (you can always go back and read the other experiment afterwards). The article then ends with a reflection on the results.


1994 ◽  
Vol 25 (5) ◽  
pp. 331-344 ◽  
Author(s):  
Peter M. Lafleur

Evapotranspiration (ET) and precipitation were measured during five summers (1989-1993 inclusive) at a subarctic forest site near Churchill, Manitoba, Canada. Mean daily ET varied from 2.14-3.18 mm d−1 during the five summers, while mean daily precipitation (P) ranged from 1.46-3.15 mm d−1. Yearly variability in summer ET was most influenced by availability of surface moisture, then by atmospheric conditions (i.e. temperature), and least of all by net radiation. In four of the five years total summer ET exceeded P resulting in significant soil water deficits and in the other year summer ET and P were similar in magnitude. The use of equilibrium evaporation (EE) as a predictor of ET was explored. Separate relationships between ET and EE were computed for all five years. Three statistically dissimilar groups of equations were found: 1989/1990, 1991/ 1992, and 1993. A single regression equation describing all years is presented.


GEOgraphia ◽  
2010 ◽  
Vol 7 (14) ◽  
Author(s):  
Márcio Piñon de Oliveira

A utopia do direito à cidade,  no  caso específico do Rio de Janeiro, começa, obrigatoriamente, pela  superação da visão dicotômica favela-cidade. Para isso, é preciso que os moradores da favela possam sentir-se tão cidadãos quanto os que têm moradias fora das favelas. A utopia do direito à cidade tem de levar a favela a própria utopia da cidade. Uma cidade que não se fragmente em oposições asfalto-favela, norte-sul, praia-subúrbio e onde todos tenham direito ao(s) seu(s) centro(s). Oposições que expressam muito mais do que diferenças de  localização e que  se apresentam recheadas de  segregação, estereótipos e  ideologias. Por outro  lado, o direito a cidade, como possibilidade histórica, não pode ser pensado exclusivamente a partir da  favela. Mas as populações  que aí habitam guardam uma contribuição inestimável para  a  construção prática  desse direito. Isso porque,  das  experiências vividas, emergem aprendizados e frutificam esperanças e soluções. Para que a favela seja pólo de um desejo que impulsione a busca do direito a cidade, é necessário que ela  se  pense como  parte da história da própria cidade  e sua transformação  em metrópole.Abstract The right  to the city's  utopy  specifically  in Rio de Janeiro, begins by surpassing  the dichotomy approach between favela and the city. For this purpose, it is necessary, for the favela dwellers, the feeling of citizens as well as those with home outside the favelas. The right to the city's utopy must bring to the favela  the utopy to the city in itself- a non-fragmented city in terms of oppositions like "asphalt"-favela, north-south, beach-suburb and where everybody has right to their center(s). These oppositions express much more the differences of location and present  themselves full of segregation, stereotypes and ideologies. On  the other  hand, the right to  the city, as historical possibility, can not be thought  just from the favela. People that live there have a contribution for a practical construction of this right. 


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Clara Inés Pardo Martínez ◽  
William Alfonso Piña ◽  
Angelo Facchini ◽  
Alexander Cotte Poveda

Abstract Background Currently, most of the world’s population lives in cities, and the rapid urbanization of the population is driving increases in the demand for products, goods and services. To effectively design policies for urban sustainability, it is important to understand the trends of flows in energy and materials as they enter and leave a city. This knowledge is essential for determining the key elements characterizing future urban growth and addressing future supply challenges. Methods This paper presents an analysis of the energy and material flows in the city of Bogotá over the time span from 2001 to 2017. Urban flows are also characterized in terms of their temporal evolution with respect to population growth to compare and identify the changes in the main input flows, wealth production, emissions and waste in the city. Results The results of the analysis are then compared with those for other selected large urban agglomerations in Latin America and worldwide to highlight similarities and make inferences. The results show that in Bogotá, there was a decrease in some of the material flows, such as the consumption of water and the generation of discharge, in recent years, while there was an increase in the consumption of energy and cement and in the production of CO2 emissions and construction materials. Solid waste production remained relatively stable. With respect to the other large cities considered, we observe that the 10-year growth rates of the flows with respect to population growth are lower in Bogotá, particularly when compared with the other urban agglomerations in Latin America. Conclusions The findings of this study are important for advancing characterizations of the trends of material and energy flows in cities, and they contribute to the establishment of a benchmark that allows for the definition and evaluation of the different impacts of public policy while promoting the sustainability of Bogotá in the coming decades.


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