Economic incentives in the system of environmental-economic relations

Environmental protection in Iraq suffers from a lack of means allocated by the government. In these conditions improving of economic mechanism of the environmental protection plays a crucial role. The main objective of the economic mechanism is to rich the goals of state environmental policy by economic measures. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2672

Source Evaluation and Trace Metal Contamination in Benthic Sediments from Equatorial Ecosystems Using Multivariate Statistical Techniques

race metals (Cd, Cr, Cu, Ni and Pb) concentrations in benthic sediments were analyzed through multi-step fractionation scheme to assess the levels and sources of contamination in estuarine, riverine and freshwater ecosystems in Niger Delta (Nigeria). The degree of contamination was assessed using the individual contamination factors (ICF) and global contamination factor (GCF). Multivariate statistical approaches including principal component analysis (PCA), cluster analysis and correlation test were employed to evaluate the interrelationships and associated sources of contamination. The spatial distribution of metal concentrations followed the pattern Pb>Cu>Cr>Cd>Ni. Ecological risk index by ICF showed significant potential mobility and bioavailability for Cu, Cu and Ni. The ICF contamination trend in the benthic sediments at all studied sites was Cu>Cr>Ni>Cd>Pb. The principal component and agglomerative clustering analyses indicate that trace metals contamination in the ecosystems was influenced by multiple pollution sources

Comparison of oxidation behavior of linear and branched alkanes

© 2019 Elsevier B.V. In this research, the oxidation behavior of six linear and branched alkanes was investigated using high-pressure differential scanning calorimeter (HP-DSC) and thermogravimetry coupled with Fourier-transform infrared spectroscopy (TG-FTIR) to compare the similarities and differences between branched and linear alkanes. The results indicated that both branched and linear alkanes showed only low-temperature oxidation (LTO), which implies that alkanes barely contribute in coke formation and thus no obvious high-temperature oxidation (HTO) was observed as no enough fuel was deposited. The LTO of linear alkanes seems to be independent of their carbon number, which, however, does not apply to branched alkanes. The oxidation behavior of branched alkanes was different from their linear chain counterparts due to the effect of their different molecule structure. Branched alkanes reacted earlier and faster at initial stage relative to their linear chain counterparts, but their reaction rates became slower at later stage with the increase of temperature. Branched alkanes can produce some oxidized compounds with C[sbnd]O group, while linear alkanes can form more carbonyl groups and some oxidized compounds (like carboxylic acids) that can help to produce more CO2 by decomposition

Combustion behavior of aromatics and their interaction with n-alkane in in-situ combustion enhanced oil recovery process: Thermochemistry

© 2019 The Korean Society of Industrial and Engineering Chemistry The combustion behavior of aromatics (p-quaterphenyl, thioxanthone, pyrene) and their interaction with n-alkane (tetracosane) were investigated by high-pressure differential scanning calorimetry (HP-DSC). Tetracosane only showed low-temperature oxidation (LTO), while p-quaterphenyl and thioxanthone only showed high-temperature oxidation (HTO). Pyrene exhibited a unique middle-high temperature oxidation (M-HTO). Tetracosane significantly promoted the HTO of p-quaterphenyl and thioxanthone, and shifted their HTO into lower temperatures. While p-quaterphenyl and thioxanthone did not significantly affect the occurrence of the LTO of tetracosane, but they did reduce the heat release and reaction rate of the LTO of tetracosane. The co-oxidation of tetracosane and pyrene triggered an intense interaction that exerts a strong inhibition on the LTO of tetracosane, and induces an explosive oxidation reaction followed by a mild oxidation from 280 to 325 °C. The intense interaction also significantly promoted the HTO of the pyrene. In general, the interaction strength is in turn pyrene + tetracosane > thioxanthone + tetracosane > p-quaterphenyl + tetracosane. Due to the strong interaction between the alkane and aromatics during their co-oxidation, the additivity of heat release in both LTO and HTO cannot be applied in terms of reaction process as well as total heat release

Combustion behavior of aromatics and their interaction with n-alkane in in-situ combustion enhanced oil recovery process: Thermochemistry

© 2019 The Korean Society of Industrial and Engineering Chemistry The combustion behavior of aromatics (p-quaterphenyl, thioxanthone, pyrene) and their interaction with n-alkane (tetracosane) were investigated by high-pressure differential scanning calorimetry (HP-DSC). Tetracosane only showed low-temperature oxidation (LTO), while p-quaterphenyl and thioxanthone only showed high-temperature oxidation (HTO). Pyrene exhibited a unique middle-high temperature oxidation (M-HTO). Tetracosane significantly promoted the HTO of p-quaterphenyl and thioxanthone, and shifted their HTO into lower temperatures. While p-quaterphenyl and thioxanthone did not significantly affect the occurrence of the LTO of tetracosane, but they did reduce the heat release and reaction rate of the LTO of tetracosane. The co-oxidation of tetracosane and pyrene triggered an intense interaction that exerts a strong inhibition on the LTO of tetracosane, and induces an explosive oxidation reaction followed by a mild oxidation from 280 to 325 °C. The intense interaction also significantly promoted the HTO of the pyrene. In general, the interaction strength is in turn pyrene + tetracosane > thioxanthone + tetracosane > p-quaterphenyl + tetracosane. Due to the strong interaction between the alkane and aromatics during their co-oxidation, the additivity of heat release in both LTO and HTO cannot be applied in terms of reaction process as well as total heat release

Effect of Hydraulic Characteristics on Fluid Transients Analysis under Different Types of Control Valves

In this study, several types of valves were used to study the impact of the valves types and closure characteristics on fluid transients. The valve closure curves, which are the variation of the effective valve opening as a function of percentage opening area, were derived for different selected valves. Six different types of valves were selected to study the effect of the valves types on fluid transient conditions. For simplification, a very simple pipeline system was assumed and presented in this study. The system is about two pipes connected in a series junction and they take the water from a constant-level reservoir at upstream and a valve at downstream. The duration of valve closure was taken as six seconds which plays an important role in the pressure development in the system. A method of characteristics is applied to compute the transient conditions under gradual closure of the valves. Valve data of various forms were compiled and reported as discharge and headloss coefficients as a function of valve opening. The effect of valve geometry and operation on the relative valve opening were compared. Discharge and headloss coefficients were also compared between valve types. The study concluded that transient conditions depend on the valve type. The comparison between the results of all valve types indicated that the changes in pressure and discharges depend on valve type where there is a difference in effective valve opening. It can be concluded that the valve with the highest value of valve effective opening has less effect on transient conditions, i.e., the faster changes of effective valve opening the larger the effect on transient conditions (discharge and the greater the magnitude of the pressure wave). This study would help to select the property valve in pipeline design

Comparison of oxidation behavior of linear and branched alkanes

© 2019 Elsevier B.V. In this research, the oxidation behavior of six linear and branched alkanes was investigated using high-pressure differential scanning calorimeter (HP-DSC) and thermogravimetry coupled with Fourier-transform infrared spectroscopy (TG-FTIR) to compare the similarities and differences between branched and linear alkanes. The results indicated that both branched and linear alkanes showed only low-temperature oxidation (LTO), which implies that alkanes barely contribute in coke formation and thus no obvious high-temperature oxidation (HTO) was observed as no enough fuel was deposited. The LTO of linear alkanes seems to be independent of their carbon number, which, however, does not apply to branched alkanes. The oxidation behavior of branched alkanes was different from their linear chain counterparts due to the effect of their different molecule structure. Branched alkanes reacted earlier and faster at initial stage relative to their linear chain counterparts, but their reaction rates became slower at later stage with the increase of temperature. Branched alkanes can produce some oxidized compounds with C[sbnd]O group, while linear alkanes can form more carbonyl groups and some oxidized compounds (like carboxylic acids) that can help to produce more CO2 by decomposition

Effect of calcite and dolomite on crude oil combustion characterized by TG-FTIR

© 2019 Elsevier B.V. This study is aimed at studying the influence of calcite and dolomite on crude oil combustion using TG-FTIR technique. According to the TG-DTG curves and the released gaseous products, the entire combustion process of crude oil can be divided into three regions: low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO). The presence of calcite or dolomite significantly promoted the continuity of reactions, thus resulting in a smooth transition from LTO to FD, and further to HTO. Specifically, the explicit boundary between LTO and FD disappeared, the reaction of fuel formation started in the later stage of LTO, and the FD process was also partly merged with HTO reaction into one reaction region, even the simultaneous occurrence of FD and HTO reactions was observed for calcite. In general, calcite and dolomite have distinct catalytic effects on crude oil combustion. Their existence made fuel deposition and its combustion easier by significantly reducing the activation energy (mainly in FD stage and the beginning of HTO stage) from about 250 to 450 kJ/mol to 150–225 kJ/mol, which thus leads to a more continuous FD-HTO process. Calcite has a superior catalytic effect than dolomite as it achieved lower values of activation energy with smaller fluctuation (maximum 175 and 225 kJ/mol for calcite and dolomite, respectively). These results indicate that the presence of calcite and dolomite (especially calcite) is favourable for accelerating crude oil combustion reaction in in-situ combustion (ISC) process