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In this study, considering different operational parameters for stirred media mill, change in specific energy was compared to the change in R x values, i.e. the cumulative weight of the material undersized to a specific sieve. R values, namely R 38 , R 75 , R 106 , were measured before and after grinding in stirred mill. The change in R x (ΔR x , %) values were calculated and they were used to evaluate the certain unit of effectual energy (E cb). This abovementioned calculation is performed by proportioning the Specific Energy (SE) to ΔR x values. The effectual part of SE is considered to be the ratio of the energy needed only for size reduction in grinding and it should be related to the ΔR x. The relative E cb ratios of different grinding conditions give the relative specific energy efficiency ratio (SE e). The relative specific energy efficiency ratio is inversely proportional to specific grinding parameters and ground product particle sizes. The relative specific energy efficiency can be considered as the relative amount of energy for various grinding conditions. The variation between relative energy amount and the previously specified particle size provides a realistic comparison of different grinding parameters. The abovementioned variation could be employed to understand the resistance particle size which is a new concept to describe the particle size at which the maximum effectual SE is directly used. In the context of this study, it was aimed to figure out the interrelation between specific energy efficiency and PSD variation along with the resistance particle size. [ABSTRACT FROM AUTHOR]

Radon is the major part of the natural indoor radioactivity. It is important to determine the indoor radon concentration for calculating the exposed radiation doses due to radon inhalation. In this study, the radon concentrations were measured in 2008 summer term at Zonguldak Karaelmas University Central Library by using CR-39 passive nuclear track detectors which were located on 12 different points in the library. It was found that, the average radon concentration on the Central Library was 67.1 Bq/m3. It was recorded that a radon concentration value at the new study room on the ground-floor was higher than 400 Bq/m3, TAEK's lower limit value for indoors. This may be a health risk for the library users and especially for the staff. Therefore, necessary precautions that must be taken have been stated. [ABSTRACT FROM AUTHOR]

Some trace elements were analyzed in Pleurotus Sajor-caju mushroom cultivated on chemithermomechanical pulp. In this experiment, phytohormones, such as 2.4-D and PS A6, were studied at concentrations of 10, 20 and 30 mg/100 ml, mixed into the pulp. Determination of mineral elements was done by flame atomic absorption spectrophotometry (Perkin Elmer model 1100 B). Sixteen mineral elements were determined in all samples. Cu, Mg, Pb, Na, Ag, Bi, Mn, Ni, Li, Co, Sb, Ca, Zn, Fe, Cr and Al contents of mushrooms, grown on treated pulp, were near control values. K was not present. [Copyright &y& Elsevier]