Cotton stalk as a potential energy source

WOS: 000188326800008Policymakers have a growing interest in the development of domestic energy sources. One renewable energy source, biomass, is receiving consideration as a potential energy source. Among agricultural biomass materials, crop residue has energy value in direct combustion and gasification as well as in the manufacture of hydrocarbon fuels. The main objective of the present study is to investigate many aspects of cotton stalk ( CS) as a potential energy source, including major properties and characteristics of CS and ways to evaluate CS. An illustrative example of Turkey's CS potential is also given. Cotton is planted on a large scale in Turkey and is one of Turkey's most important agricultural crops as Turkey is one of the 8 countries producing 85% of the world's cotton. It is estimated that the maximum amount of CS available in Turkey is 4.41 million tons annually, and Turkey's energy equivalence of CS is 75.62 PJ ( 1.717 million tons of oil equivalent), which corresponds to 6.3% of Turkey's primary energy production in 1999. A net energy of 39,028 MJ/ ha may be produced from a cotton field every year, which is why there is interest in CS use. A good residue management system should also be installed throughout the country for the optimum use of these residues. It is also expected that the results of this study will be helpful in developing highly applicable and productive planning for energy policies

Evaluation of Aegean region agro-industrial wastes as a potential energy source

WOS: 000178291700007Especially in the last decade, the interest in energy generation from biomass and waste materials has been increasing in Turkey. The reasons for this are mainly twofold: (1) The utilization of biomass energy creates new job possibilities on the agricultural market, and (2) biomass energy yields lower air emissions than fossil fuels. Parallel to the agro-industrial development in the country, different types of wastes have been dramatically increasing in the Aegean region. The main objective of the present study is to evaluate the potential and availability of the agro-industrial wastes produced in this region with respect to energy production. This evaluation was based on a previously conducted questionnaire-based survey aiming to determine the potential of these wastes in the 8 cities of this region and 2 neighboring cities. The cities all had similar economical and agricultural structure, with business concentrated in 9 different agro-industrial sectors. The evaluation indicates that this region has a significant potential of agro-industrial wastes for energy production, and the results obtained can assist national government for future planning studies. However a good waste management system should be installed throughout the country for the optimum use of these wastes

Utilization of olive cake as a potential energy source in Turkey

WOS: 000182369400004With the energy picture getting worse every day, it is now desirable to search for alternative energy sources. This has led to renewed interest in olive cake (OC) as an alternative energy source in Turkey due to some of its advantages, such as negligible sulfur content, reducing environmental impact, low cost compared to fossil fuels, problem-free storage, and lack of transportation requirements if used in an olive oil production facility. OC is a byproduct of olive oil production and is a solid material consisting of seed particles and the fleshy parts of olives. The Mediterranean region represents 98% of the world's olive tree population. In this regard, Turkey is among the top 5 main olive oil-producing countries in the world. The main objective of the present study is to investigate the potential and utilization of OC in the country. It is estimated that over 360,000 tons of OC, corresponding to an average of 150,000 tons of oil equivalent (toe), were produced in the 2000-2001 season in Turkey. Suitable combustion systems, such as fluidized bed systems, stoker fed from the bottom with secondary air supply, etc., should be used for efficient energy production from the OC. There are no limiting values related to emissions for OC in the Turkish regulations of air quality yet. There are, however, some studies being conducted by the Ministry of Environment for the determination of these limiting values. In light of the present study, it may be concluded that OC is a very promising source of energy in Turkey

Multicollinearity in regression: an efficiency comparison between Lp-norm and least squares estimators

Multicollinearity is one of the most important issues in regression analysis, as it produces unstable coefficients’ estimates and makes the standard errors severely inflated. The regression theory is based on specific assumptions concerning the set of error random variables. In particular, when errors are uncorrelated and have a constant variance, the ordinary least squares estimator produces the best estimates among all linear estimators. If, as often happens in reality, these assumptions are not met, other methods might give more efficient estimates and their use is therefore recommendable. In this paper, after reviewing and briefly describing the salient features of the methods, proposed in the literature, to determine and address the multicollinearity problem, we introduce the Lpmin method, based on Lp-norm estimation, an adaptive robust procedure that is used when the residual distribution has deviated from normality. The major advantage of this approach is that it produces more efficient estimates of the model parameters, for different degrees of multicollinearity, than those generated by the ordinary least squares method. A simulation study and a real-data application are also presented, in order to show the better results provided by the Lpmin method in the presence of multicollinearity