Selection of Mixed Refrigerant for CBM Liquefaction System and its Optimization Analysis

2012 ◽  
Vol 443-444 ◽  
pp. 193-197
Author(s):  
Q.H. Fan ◽  
H.Y. Li ◽  
L.X. Jia ◽  
Q.H. Fan ◽  
Yi Min Shao ◽  
...  

In the mixed refrigerant cycle, the key technology is the choosing of the mixed refrigerant and its optimization mixture ratio. Based on a small-scale CBM liquefaction system LNG5, which the capacity is 5 cube meters LNG per day, the numerical simulation and optimization for the LNG5 are carried out. It provides the composition of the mixed refrigerant. It analyzes the effects of mixed refrigerant components on the temperature difference of the heat exchangers and the vapor fraction of the key nodes. The analysis results show that a reasonable mixture ratio of mixed refrigerant is given, such as CH4 mole fraction being 41.8% ~ 44.3%, C2H6 mole fraction being 40.8% ~ 42.2%, C5H12 molar fraction being 14.3% ~ 16%, and N2 mole fraction being 1.5% ~ 3.3%. The results provide guidelines for the design of the small-scale CBM liquefaction device, and for the application and commissioning of CBM liquefaction plant in China.

2015 ◽  
Vol 47 (1) ◽  
pp. 5-17
Author(s):  
Jolanta Korycka-Skorupa

Abstract The author discuss effectiveness of cartographic presentations. The article includes opinions of cartographers regarding effectiveness, readability and efficiency of a map. It reminds the principles of map graphic design in order to verify them using examples of small-scale thematic maps. The following questions have been asked: Is the map effective? Why is the map effective? How do cartographic presentation methods affect effectiveness of the cartographic message? What else can influence effectiveness of a map? Each graphic presentation should be effective, as its purpose is to complete written word, draw the recipients’ attention, make text more readable, expose the most important information. Such a significant role of graphics results in the fact that graphic presentations (maps, diagrams) require proper preparation. Users need to have a chance to understand the graphics language in order to draw correct conclusions about the presented phenomenon. Graphics should demonstrate the most important elements, some tendencies, and directions of changes. It should generalize and present a given subject from a slightly different perspective. There are numerous examples of well-edited and poorly edited small-scale thematic maps. They include maps, which are impossible to interpret correctly. They are burdened with methodological defects and they cannot fulfill their task. Cartography practice indicates that the principles related to graphic design of cartographic presentation are frequently omitted during the process of developing small-scale thematic maps used – among others – in the press and on the Internet. The purpose of such presentations is to quickly interpret them. On such maps editors’ problems with the selection of an appropriate symbol and graphic variable (fig. 1A, 9B) are visible. Sometimes they use symbols which are not sufficiently distinguishable nor demonstrative (fig. 11), it does not increase their readability. Sometime authors try too hard to reflect presented phenomenon and therefore the map becomes more difficult to interpret (fig. 4A,B). The lack of graphic sense resulting in the lack of graphic balance and aesthetics constitutes a weak point of numerous cartographic presentations (fig. 13). Effectiveness of cartographic presentations consists of knowledge and skills of the map editor, as well as the recipients’ perception capabilities and their readiness to read and interpret maps. The qualifications of the map editor should include methodological qualifications supported by the knowledge of the principles for cartographic symbol design, as well as relevant technical qualifications, which allow to properly use the tools to edit a map. Maps facilitate the understanding of texts they accompany and they present relationships between phenomenon better than texts, appealing to the senses.


Author(s):  
Afodu Osagie John ◽  
Shobo Bolatito Adenike ◽  
Ayo-Bello Taofeek Ayodeji ◽  
Abasilim Chinwe Frances

Broiler birds are widely praised for its palatability and nutritious values which are mainly for meat purpose, and also serves as source of income to many households in Nigeria. The broiler industry is faced with high cost of production thereby reducing the farmers profit. The study was conducted in three Geopolitical zones in Nigeria. A multistage sampling technique was adopted for this study for the selection of 540 broilers farmers out which 392 returned a well filled questionnaire where data were extracted for the study. Data for this study were analysed using descriptive (frequency and percent) budgetary analysis and inferential (Logit regression) statistics. Factors affecting the profit level of broiler farmers were age (γ1= -0.145, p= 10%), households size (γ3= -5.477, p=10%), educational status of the farmers (γ4= 0.228, p= 5%), number of birds (γ7= 0.575, p= 5%), cost of feed (γ8= -1.022, p= 1%), cost of water (γ9= -1.277, p= 1%), cost of drugs (γ10= -1.640, p= 5%) and cost of chick (γ11= -7.104, p= 1%). Young people should be encouraged to be involved in production of broiler, since agriculture has aging population and help in employment creation. Farmers should maintain a low number of households so as to increase their profit. The farmers should have some forms of education on the production of broilers so as to enhance their profit.


2013 ◽  
Vol 21 (12) ◽  
pp. 3029-3036
Author(s):  
赵阳 ZHAO Yang ◽  
巩岩 GONG Yan
Keyword(s):  

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