scholarly journals Determination of Optimum Flotation Parameters of Zonguldak Fine Hard Coal by Using Efficiency Index

2016 ◽  
Vol 16 (3) ◽  
pp. 759-769 ◽  
Author(s):  
Özcan Öney ◽  
Emrecan Bilgin
Keyword(s):  
Efficiency Index ◽  
Hard Coal

scholarly journals Comparative evaluation of 24 reference evapotranspiration equations applied on an evergreen-broadleaved forest

2017 ◽  
Vol 49 (4) ◽  
pp. 1028-1041 ◽  
Author(s):  
Athanassios Bourletsikas ◽  
Ioannis Argyrokastritis ◽  
Nikolaos Proutsos
Keyword(s):  
Goodness Of Fit ◽  
Hydrological Cycle ◽  
Reference Evapotranspiration ◽  
Potential Evapotranspiration ◽  
Efficiency Index ◽  
Daily Basis ◽  
Forest Environment ◽  
Statistical Parameters ◽  
Model Efficiency

Abstract Reference evapotranspiration (ET0) is a major component of the hydrological cycle. Its use is essential both for the hydrological rainfall–runoff assessment models and determination of water requirements in agricultural and forest ecosystems. This study investigates the performance of 24 different methods, which produce ET0 or potential evapotranspiration estimates above a grass-covered ground in a Mediterranean forest environment in Greece and compares the derived results with those of the presumed most accurate and scientifically acceptable Penman–Monteith method (ETP-M). Their performance was evaluated on a daily basis for a period of 17 years, using 17 different statistical parameters of goodness of fit. The results showed that some empirical methods could serve as suitable alternatives. More specifically, Copais (ETCOP), Hargreaves original (ETHAR), and Valiantzas2 (ETVA2) methods, exhibited very good values of the model efficiency index, EF (0.934, 0.932, and 0.917, respectively) and the index of agreement, d (0.984, 0.982, and 0.977, respectively). Additionally, the differences of the estimated mean daily value against the respective ETP-M value (rt index) for all methods had a range of −27.8% (Penman – ETPEN) to +59.5% (Romanenko – ETROM), while Copais (ETCOP), Hargreaves–Samani modified1 (ETHS1), and STU (ETSTU) yielded the best values (−0.06%, +0.06%, and 0.22%, respectively).

scholarly journals Determination of the effective thermal conductivity of solid fuels by the laser flash method

2014 ◽  
Vol 35 (3) ◽  
pp. 3-16 ◽  
Author(s):  
Monika Kosowska-Golachowska ◽  
Władysław Gajewski ◽  
Tomasz Musiał
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
Laser Flash ◽  
Physical Structure ◽  
Solid Fuels ◽  
Flash Method ◽  
Hard Coal ◽  
Coal Rank ◽  
Dominant Effect

Abstract In this study, a new laser flash system was proposed for the determination of the thermal conductivity of brown coal, hard coal and anthracite. The main objective of the investigation was to determine the effect of coal rank, composition, physical structure and temperature on thermal conductivity. The solid fuels tested were medium conductors of heat whose determined thermal conductivities were in the range of 0.09 to 0.23W/(mK) at room temperature. The thermal conductivity of the solid fuels tested typically increased with the rank of coal and the measurement temperature. The results of this study show that the physical structure of solid fuels and temperature have a dominant effect on the fuels’ thermal conductivity.

scholarly journals The Investigation of Mercury Contents in Polish Coal Samples

2013 ◽  
Vol 39 (2) ◽  
pp. 141-150 ◽  
Author(s):  
Michał Wichliński ◽  
Rafał Kobyłecki ◽  
Zbigniew Bis
Keyword(s):  
Electricity Generation ◽  
Volatile Matter ◽  
Proximate Analysis ◽  
Mercury Content ◽  
Hard Coal ◽  
Fixed Carbon ◽  
Heating Value ◽  
High Heating Value ◽  
Enrichment Process

Abstract This paper presents the results of the investigation associated with the determination of mercury content in Polish hard coal and lignite samples. Those coals are major fuels used for electricity generation in Poland. The results indicated that the average content of mercury in the coal samples was roughly about 100 ng/g. Apart from the determination of the mercury contents a detailed ultimate and proximate analysis of the coal samples was also carried out. The relationships between the mercury content and ash, as well as fixed carbon, volatile matter, sulfur, and high heating value of the coal samples were also established. Furthermore, the effect of coal enrichment was also investigated, and it was found that the enrichment process enabled the removal of up to 75% of the coal mercury from the samples.

Sign in / Sign up

Export Citation Format

Share Document