For predictive purposes and for understanding the relationship between the US market and Canadian newsprint producers an econometric model was built. In this study, a simultaneous-equation model was developed, which c...For predictive purposes and for understanding the relationship between the US market and Canadian newsprint producers an econometric model was built. In this study, a simultaneous-equation model was developed, which consisted of four equations, one each for the supply, export, consumption and price of newsprint. The period of 1955-1986 was covered by this model. The data for the years 1985 and 1986 were reserved to test the predictive power of the model. In fitting the four equations for the period of 1955 -1984, the coefficients of determination, the R -square values, between observed and predicted values were higher than 99 per cent. The test results of the forecasting power showed that there was no statistically significant difference between predicted and observed values at the 5 per cent level of significance. Sources of forecasting error are expressed as three partial inequality coefficients associated with bias, variance and covariance of predicted and observed values. The error could not be展开更多
The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additiv...The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additives--chemicals, black mold enzyme, and chemicals together with black mold enzyme, are studied. The first part of the experiment was to find the optimal amount of chemicals and the optimal pH through the use of sodium hydroxide and surfactant. As a result, 0.2% of sodium hydroxide and 0.4% of surfactant on oven dried weight at pH 9 was found to be the optimal condition for the deinked pulp to yield the lowest ERIC （effective residual concentration） and the highest brightness. The second part of the experiment was to find the optimal amount of black mold enzyme used in the deinking process. As a result, the optimal condition for deinked pulp to retain the lowest ERIC and the highest brightness was 100 ppm of black mold enzyme and 10 minutes of enzyme reaction time. The third part of experiment was to study the de-inking ability of black mold enzyme and chemicals. Consequently, with 30 min of chemicals reaction time and 60 min of black mold reaction time, the deinked pulp retained low ERIC but higher brightness.展开更多
In Iran, due to abundant restrictions on harvesting wood from northern forests by implementing the preservation project and also lack of possibility for sufficient wood production, development of the area of planting ...In Iran, due to abundant restrictions on harvesting wood from northern forests by implementing the preservation project and also lack of possibility for sufficient wood production, development of the area of planting poplar is quite inevitable. Poplar wood properties have special importance to produce many wood production, particularly pulp and paper. Paper factories are the major consumers of poplar wood at the global level and this is because of unique morphological, physical, mechanical and technological properties of poplar wood. Therefore, regarding the importance of using this species in making various printing and writing paper, packaging or carton, cardboard and newsprint, in this study, costs of poplar production in one hectare including planting and harvesting were examined and determined. Then, based on conversion coefficients of FAO, required round wood, productivity and the cost of poplar wood were calculated for the producing various kinds of paper. The results indicate that carton and cardboard paper or packaging allocate the lowest cost and highest return, while printing and writing paper had highest cost and lowest return in terms of poplar wood supply needed for paper production.展开更多
文摘For predictive purposes and for understanding the relationship between the US market and Canadian newsprint producers an econometric model was built. In this study, a simultaneous-equation model was developed, which consisted of four equations, one each for the supply, export, consumption and price of newsprint. The period of 1955-1986 was covered by this model. The data for the years 1985 and 1986 were reserved to test the predictive power of the model. In fitting the four equations for the period of 1955 -1984, the coefficients of determination, the R -square values, between observed and predicted values were higher than 99 per cent. The test results of the forecasting power showed that there was no statistically significant difference between predicted and observed values at the 5 per cent level of significance. Sources of forecasting error are expressed as three partial inequality coefficients associated with bias, variance and covariance of predicted and observed values. The error could not be
文摘The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additives--chemicals, black mold enzyme, and chemicals together with black mold enzyme, are studied. The first part of the experiment was to find the optimal amount of chemicals and the optimal pH through the use of sodium hydroxide and surfactant. As a result, 0.2% of sodium hydroxide and 0.4% of surfactant on oven dried weight at pH 9 was found to be the optimal condition for the deinked pulp to yield the lowest ERIC （effective residual concentration） and the highest brightness. The second part of the experiment was to find the optimal amount of black mold enzyme used in the deinking process. As a result, the optimal condition for deinked pulp to retain the lowest ERIC and the highest brightness was 100 ppm of black mold enzyme and 10 minutes of enzyme reaction time. The third part of experiment was to study the de-inking ability of black mold enzyme and chemicals. Consequently, with 30 min of chemicals reaction time and 60 min of black mold reaction time, the deinked pulp retained low ERIC but higher brightness.
文摘In Iran, due to abundant restrictions on harvesting wood from northern forests by implementing the preservation project and also lack of possibility for sufficient wood production, development of the area of planting poplar is quite inevitable. Poplar wood properties have special importance to produce many wood production, particularly pulp and paper. Paper factories are the major consumers of poplar wood at the global level and this is because of unique morphological, physical, mechanical and technological properties of poplar wood. Therefore, regarding the importance of using this species in making various printing and writing paper, packaging or carton, cardboard and newsprint, in this study, costs of poplar production in one hectare including planting and harvesting were examined and determined. Then, based on conversion coefficients of FAO, required round wood, productivity and the cost of poplar wood were calculated for the producing various kinds of paper. The results indicate that carton and cardboard paper or packaging allocate the lowest cost and highest return, while printing and writing paper had highest cost and lowest return in terms of poplar wood supply needed for paper production.
