Shale Gas: Current Perspectives and Future Prospects in Turkey and the World

With the increased natural gas prices and advancement in the horizontal drilling and hydraulic fracturing technology, there is a high interest in shale gas reservoirs in the world and in Turkey. However, gas production from shale gas reservoirs is quite different than conventional gas reservoirs because permeability in shale gas reservoirs is very low and production mechanism is different due to adsorbed gas and free gas together in these reservoirs. The aim of study is to clarify shale gas reservoirs in terms of the world and Turkey's shale gas potential, gas production mechanism, and current techniques applied

Hydrate Inhibition with PEO (Poly 2-ethyl-2-oxazoline)

This study is aimed at investigating the effects of a poly 2-ethyl-2-oxazoline-type polymer on the prevention of methane hydrate formation. During the study, seven experiments with low concentrations of poly 2-ethyl-2-oxazoline (0 to 1 wt%) were run in a batch-type reactor. The analysis of the experimental study indicates that poly 2-ethyl-2-oxazoline can be considered as a potential kinetic inhibitor for hydrate formation

Comprehensive literature review on CH4-CO2 replacement in microscale porous media

Gas production studies from natural gas hydrate reservoirs have been the subject of extensive research in recent years. Although CH4-CO2 replacement production method from gas hydrates has many advantages, the number of the studies related to this production method are less than depressurization production method studies, especially in microscale porous media. Hence, this paper presents a comprehensive literature review on CH4-CO2 replacement to better understand the associated processes and mechanisms in microscale porous media with emphasis on micromodel experiments, 3D imaging, other visualization testing method and pore network modelling. Moreover, the advantages and disadvantages of currently available CH4-CO2 replacement studies were investigated. The critical issues of the replacement method were underlined and new suggestions have been offered for future investigations. � 2018 Elsevier B.V.Scopu

Chromatographic methods for the simultaneous determination of binary mixture of Saxagliptin HCl and Metformin HCl

Two chromatographic methods were suggested for the simultaneous determination of a binary mixture containing Saxagliptin HCl (SAG) and Metformin HCl (MET). First method was RP-HPLC method. Chromatographic separation was done on Kinetex⢠columnâC18 (4.6 Ã 150 mm, 2.6 µm) using mobile phase consisted of acetonitrile:phosphate buffer pH = 4.5 ± 0.1 adjusted with orthophosphoric acid (13:87, v/v). Isocratic elution at a flow rate 1.5 mL/min and UV detection at 220.0 nm was performed. Second method was spectro-densitometric method. Chromatographic separation was done on precoated silica gel aluminium plates 60 F254 as a stationary phase and developing system consisting of chloroform:methanol:formic acid (80:20:0.3, by volume). The density of the separated bands was measured by UV detector at 210.0 nm. The proposed methods were validated as per the ICH guidelines parameters like Linearity, precision, accuracy, selectivity, limit of detection and limit of quantitation. Statistical comparison was done between the obtained results and those obtained by the reported methods, showing no significant difference with respect to accuracy and precision. Keywords: Saxagliptin HCl, Metformin HCl, RP-HPLC, TL

Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation

Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY) and Flunixin Meglumine (FLU). The first method, dual wavelength (DW), depends on measuring the difference in absorbance (ΔA 273.4–327 nm) for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7–275.7 nm. The second method, first-derivative spectrophotometric method (1D), depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5–324.8 nm and ΔP 249.6–286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD), depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones

Validated chromatographic methods for the simultaneous determination of Mometasone furoate and Formoterol fumarate dihydrate in a combined dosage form

Two chromatographic methods were developed and validated for the simultaneous determination of Mometasone furoate (MO) and Formoterol fumarate dihydrate (FOR). Combination of MO and FOR is used for the treatment of asthma in patients suffering from reversible obstructive airway disease. The first chromatographic method was based on using aluminum TLC plates pre-coated with silica gel GF254 as the stationary phase and chloroform:ethyl acetate:methanol:toluene:formic acid (5:2:2:2:0.1, by volume) as the mobile phase followed by densitometric measurement of the separated bands at 233 nm. The second method is a high performance liquid chromatographic method for the separation and determination of MO and FOR using reversed phase C18 column with isocratic elution. The mobile phase composed of methanol: 0.5% ammonium acetate pH adjusted with acetic acid (80:20, v/v) at a flow rate of 1.0 mL/min. Quantitation was achieved with UV detection at 220 nm. The specificity of the developed methods was investigated by analyzing the pharmaceutical dosage form. The validity of the proposed methods was assessed using the standard addition technique. The obtained results were statistically compared with those obtained by the reported methods, showing no significant difference with respect to accuracy and precision at p = 0.05