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651.
Quantifying the Effects of Forest Management Strategies on the Production of Forest Values: Timber,Carbon, Oxygen,Water, and Soil 总被引:1,自引:0,他引:1
Emin Zeki Başkent Sedat Keleş Ali İhsan Kadıoğulları Özkan Bingöl 《Environmental Modeling and Assessment》2011,16(2):145-152
Forest management practices alter forest structure quantified with ecosystem characteristics and values. In this paper, we utilized a forest management simulation model to assess the effects of three forest management strategies focusing on timber production, carbon sequestration, oxygen production, soil erosion, and water production of a forest management unit in Turkey. A forest simulation model “ETÇAPSimülasyon” was developed and used to project forest ecosystem development over 100 years under three forest management policies of timber-oriented forest management (TFM), multipurpose forest management (MFM), and no intervention (NI). The results showed that TFM strategy produced more timber and its net present value than MFM and NI strategies did. The amount of carbon sequestration and oxygen production potential was also found to be the highest with TFM strategy than with the MFM and NI strategies. Compared with the other strategies, however, NI strategy produced the highest amount of water production and soil losses over the planning horizon. The effects of a forest management strategy depend mainly on the initial forest structure, the rate of development and the level of forest management interventions. Therefore, forest dynamics under various management strategies should be explained before the final management decision. Understanding long-term effects of any management strategies on forest structure will provide the basis for better reaching the management objectives. 相似文献
652.
Neda Saraygord-Afshari Fereshteh Abbasisiar Parviz Abdolmaleki Mahdi Ghiassi-Nejad Ali Attarilar 《The Environmentalist》2011,31(3):308-314
Thirty-eight different milk and milk powder samples from Tehran-Iran were collected and analyzed for 90Sr activity using a method in which the daughter product of 90Sr decay (90Y) was extracted by tributyl phosphate from ashed milk. 90Y was then back extracted with water, and oxalate was precipitated . Following the sample analyzing, beta counting was performed
with an ultralow-level liquid scintillation spectrometer. The quality control and assurance of the method were obtained by
standard samples prepared with an IAEA-certified reference material. The mean determined 90Sr activity concentration in the analyzed milk and milk powder (0.225 ± 0.042 and 0.216 ± 0.024 Bq kg−1, respectively) showed that the radioactivity concentration in our samples was too low to induce biological hazards. These
data can provide useful information of the background level of contamination, which in turn can be used in the following environmental
monitoring programs. 相似文献
653.
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655.
A comparative study of biopolymers and alum in the separation and recovery of pulp fibres from paper mill effluent by flocculation 总被引:1,自引:0,他引:1
Sumona Mukherjee Soumyadeep Mukhopadhyay Agamuthu Pariatamby Mohd. Ali Hashim Jaya Narayan Sahu Bhaskar Sen Gupta 《环境科学学报(英文版)》2014,26(9):1851-1860
Recovery of cellulose fibres from paper mill effluent has been studied using common polysacchatides or biopolymers such as Guar gum, Xanthan gum and Locust bean gum as flocculent. Guar gum is commonly used in sizing paper and routinely used in paper making. The results have been compared with the performance of alum, which is a common coagulant and a key ingredient of the paper industry. Guar gum recovered about 3.86 mg/L of fibre and was most effective among the biopolyrners. Settling velocity distribution curves demonstrated that Guar gum was able to settle the fibres faster than the other biopolymers; however, alum displayed the highest particle removal rate than all the biopolymers at any of the settling velocities. Alum, Guar gum, Xanthan gum and Locust bean gum removed 97.46%, 94.68%, 92.39% and 92.46% turbidity of raw effluent at a settling velocity of 0.5 cm/min, respectively. The conditions for obtaining the lowest sludge volume index such as pH, dose and mixing speed were optimised for guar gum which was the most effective among the biopolymers. Response surface methodology was used to design all experiments, and an optimum operational setting was proposed. The test results indicate similar performance of alum and Guar gum in terms of fioc settling velocities and sludge volume index. Since Guar gum is a plant derived natural substance, it is environmentally benign and offers a green treatment option to the paper mills for pulp recycling. 相似文献
656.
Ali Vazini Shayan Reza Azar Afza Reza Teimouri 《Journal of Manufacturing Processes》2013,15(4):644-658
This work deals with parametric study of dry wire EDM (WEDM) process of cemented tungsten carbide. Experiments have been conducted using air as dielectric medium to investigate effects of pulse on time, pulse off time, gap set voltage, discharge current and wire tension on cutting velocity (CV) surface roughness (SR) and oversize (OS). Firstly, a series of exploratory experiments were carried out to identify appropriate gas and its pressure. Afterward, preliminary experiments were conducted to investigate effects of process parameters on dry WEDM characteristics and find appropriate ranges for each factor. Then a central composite rotatable method was employed to design experiments based on response surface methodology (RSM). Empirical models were developed to create relationships between process factors and responses by considering to analysis of variances (ANOVA). To increase the predictability of the process, intelligent models have been developed based on back-propagation neural network (BPNN) and accuracy of these models was compared with mathematical models based on root mean square error (RMSE) and prediction error percent (PEP). In order to select optimal solutions in the cases of single-objective and multi-objectives optimization problems, optimization includes two main approaches. First approach was based on mathematical model and desirability function. Also second approach was designed based on neural network and particle swarm optimization. These approaches were applied in both cases of single-objective and multi-objectives optimization problems and their results were compared with together. Results indicated that selection of air at inlet pressure of 1.5 bar is really appropriate for conducting experiments of next stages. Also, the BPNN creates more accurate prediction rather than mathematical model. Moreover, the BPNN-PSO approach was more efficient in optimization of process rather than mathematical model-desirability function in respect with validation tests. 相似文献
657.
Ganie Showkat Ali Ali Akbar Mir Tariq Ahmad Mazumdar Nasreen 《Journal of Polymers and the Environment》2022,30(2):504-515
Journal of Polymers and the Environment - Niacin, an essential B-complex vitamin, used in the treatment of nonalcoholic fatty liver disease is the first perceived lipid regulating medication,... 相似文献
658.
Balasbaneh Ali Tighnavard Yeoh David Juki Mohd Irwan Ibrahim Mohd Haziman Wan Abidin Ahmad Razin Zainal 《Environmental science and pollution research international》2021,28(28):37387-37399
Environmental Science and Pollution Research - This research aims to assess the sustainability of the most common earth-retaining walls (Gravity Walls and Cantilever Walls) in terms of... 相似文献
659.
Environmental Science and Pollution Research - In Wuhan city, China, a pneumonia-like disease of unknown origin triggered a catastrophe. This disease has spread to 215 nations, affecting a diverse... 相似文献
660.
Faisal Muhammad Chunping Xia Abbas Azhar Raza Muhammad Haseeb Akhtar Shoaib Ajmal Muhammad Arslan Ali Abdelrahman 《Environmental science and pollution research international》2021,28(32):43777-43791
Environmental Science and Pollution Research - Climate change is severely damaging the agricultural system of many food producing regions worldwide. Small/subsistent livestock herders are the most... 相似文献