Iron and steel industry is an important sector of Iran's economy.Choghart iron ore mine is an important iron ore producer of Iran steel industry.Phosphorous contained in the iron ore concentrates of Choghart mine ...Iron and steel industry is an important sector of Iran's economy.Choghart iron ore mine is an important iron ore producer of Iran steel industry.Phosphorous contained in the iron ore concentrates of Choghart mine has a detrimental effect on the steel making process,whereby this causes cracks to form in the refractory lining of blast furnaces.In the past,about 1.43 Mt of low-grade and 4.53 Mt of high-phosphorous materials had been transported to low grade and high phosphorous stockpiles,respectively,for future beneficiation.As a result of the progressive depletion of high-grade ore and establishment of beneficiation plant in Choghart,exploitation of these two stockpiles in this mine became an important issue.In this work,a linear goal programming(GP) model was developed in order to determine the optimum iron ore blend in terms of quality from low grade and high phosphorous stockpiles of Choghart mine.The model was solved by the SOLVER V.9 program.Results show that feeding with acceptable quality(w(Fe)≥50% and w(P)≤1.2%,mass fraction) materials can be blended from stockpiles that satisfy the needs of the Choghart processing line.展开更多
India is a major player in international cotton markets as it is the world＇s second largest cotton producer, consumer and exporter in 2009-2010. In this context, this paper assesses the competitiveness of Indian cott...India is a major player in international cotton markets as it is the world＇s second largest cotton producer, consumer and exporter in 2009-2010. In this context, this paper assesses the competitiveness of Indian cotton producers and potential implications for India as a competitor in the world cotton market. This paper developed an updated estimate of the costs of cotton production in India and developed representative farm models for cotton production in three important cotton production states （Gujarat, Maharashtra and Andhra Pradesh） of India. In this research, Rapid Rural Appraisal （RRA） methodology has been adopted to collect information for developing representative farm models. These models are further subjected to stochastic simulation to understand the impact of government policies like subsidies to various inputs on farm level profitability and ultimately on the competitiveness of Indian cotton in international markets. This paper also analyzed the impact of national fiber policy of the government of India on the cotton processing sector in India. The results demonstrate that the net income of the cotton farmers will decrease considerably without the presence of fertilizer subsidies. The study also concludes that if the objectives of the national fiber policy are fulfilled, India will export more of value added cotton products like textiles and garments rather than raw cotton.展开更多
An exergy analysis was performed considering the combustion of methane and agro-industrial residues produced in Portugal (forest residues and vines pruning). Regarding that the irreversibilities of a thermodynamic pro...An exergy analysis was performed considering the combustion of methane and agro-industrial residues produced in Portugal (forest residues and vines pruning). Regarding that the irreversibilities of a thermodynamic process are path dependent, the combustion process was considering as resulting from different hypothetical paths each one characterized by four main sub-processes: reactant mixing, fuel oxidation, internal thermal energy exchange (heat transfer), and product mixing. The exergetic efficiency was computed using a zero dimensional model developed by using a Visual Basic home code. It was concluded that the exergy losses were mainly due to the internal thermal energy exchange sub-process. The exergy losses from this sub-process are higher when the reactants are preheated up to the ignition temperature without previous fuel oxidation. On the other hand, the global exergy destruction can be minored increasing the pressure, the reactants temperature and the oxygen content on the oxidant stream. This methodology allows the identification of the phenomena and processes that have larger exergy losses, the understanding of why these losses occur and how the exergy changes with the parameters associated to each system which is crucial to implement the syngas combustion from biomass products as a competitive technology.展开更多
文摘Iron and steel industry is an important sector of Iran's economy.Choghart iron ore mine is an important iron ore producer of Iran steel industry.Phosphorous contained in the iron ore concentrates of Choghart mine has a detrimental effect on the steel making process,whereby this causes cracks to form in the refractory lining of blast furnaces.In the past,about 1.43 Mt of low-grade and 4.53 Mt of high-phosphorous materials had been transported to low grade and high phosphorous stockpiles,respectively,for future beneficiation.As a result of the progressive depletion of high-grade ore and establishment of beneficiation plant in Choghart,exploitation of these two stockpiles in this mine became an important issue.In this work,a linear goal programming(GP) model was developed in order to determine the optimum iron ore blend in terms of quality from low grade and high phosphorous stockpiles of Choghart mine.The model was solved by the SOLVER V.9 program.Results show that feeding with acceptable quality(w(Fe)≥50% and w(P)≤1.2%,mass fraction) materials can be blended from stockpiles that satisfy the needs of the Choghart processing line.
文摘India is a major player in international cotton markets as it is the world＇s second largest cotton producer, consumer and exporter in 2009-2010. In this context, this paper assesses the competitiveness of Indian cotton producers and potential implications for India as a competitor in the world cotton market. This paper developed an updated estimate of the costs of cotton production in India and developed representative farm models for cotton production in three important cotton production states （Gujarat, Maharashtra and Andhra Pradesh） of India. In this research, Rapid Rural Appraisal （RRA） methodology has been adopted to collect information for developing representative farm models. These models are further subjected to stochastic simulation to understand the impact of government policies like subsidies to various inputs on farm level profitability and ultimately on the competitiveness of Indian cotton in international markets. This paper also analyzed the impact of national fiber policy of the government of India on the cotton processing sector in India. The results demonstrate that the net income of the cotton farmers will decrease considerably without the presence of fertilizer subsidies. The study also concludes that if the objectives of the national fiber policy are fulfilled, India will export more of value added cotton products like textiles and garments rather than raw cotton.
基金the Portuguese Foundation for Science and Technology (FCT) for the given support to the grant SFRH/BPD/71686the project PTDC/AAC-AMB/103119/2008
文摘An exergy analysis was performed considering the combustion of methane and agro-industrial residues produced in Portugal (forest residues and vines pruning). Regarding that the irreversibilities of a thermodynamic process are path dependent, the combustion process was considering as resulting from different hypothetical paths each one characterized by four main sub-processes: reactant mixing, fuel oxidation, internal thermal energy exchange (heat transfer), and product mixing. The exergetic efficiency was computed using a zero dimensional model developed by using a Visual Basic home code. It was concluded that the exergy losses were mainly due to the internal thermal energy exchange sub-process. The exergy losses from this sub-process are higher when the reactants are preheated up to the ignition temperature without previous fuel oxidation. On the other hand, the global exergy destruction can be minored increasing the pressure, the reactants temperature and the oxygen content on the oxidant stream. This methodology allows the identification of the phenomena and processes that have larger exergy losses, the understanding of why these losses occur and how the exergy changes with the parameters associated to each system which is crucial to implement the syngas combustion from biomass products as a competitive technology.
