−Segregation and deposition of hydrate particles observed in flowloop experiments are required to be investigated more thoroughly to understand the hydrate plugging mechanism in offshore flowlines. We used natural gas as gas phase and selected three different systems as liquid phase, which are pure water only, kinetic hydrate inhibitor added aqueous solution, and water+decane mixture, respectiv...

Gas hydrate blockage in pipelines during offshore production becomes a major problem with increasing water depth. In this work, a series of experiments on gas hydrate formation in a flow loop was performed with low flow rates of 0.33, 0.66, and 0.88 m/s; the effects of the initial subcooling, flow rate, pressure, and morphology were investigated for methane hydrate formation in the flow loop. T...

The presence of structure H (sH) methane hydrate in natural environments, in addition to the well-known structure-I (sI) and II (sII) hydrates, has recently been documented. Methane in the presence of condensates (C5-C7) forms sH hydrate at lower pressure than the sI hydrate. Thus, the occurrence of sH methane hydrate is likely to have both beneficial and negative practical implications. On the...

This paper reports the influence of sucrose on the preservation of CO2 hydrate crystal samples. The particle diameter of hydrate samples were 1.0 and 5.6-8.0 mm. Mass fraction of sucrose in the sample was 0.16. The samples were stored at the aerated condition under atmospheric pressure and at the temperature of 253 or 258 K. The results indicated that the mass fractions of CO2 hydrate in the sa...

how to cite this article: ashrafimr, azizi malamiri r, zamani gr, mohammadi m, hosseini f. sleep inducing for eeg recording in children: a comparison between oral midazolam and chloral hydrate. iran j child neurol. 2013 winter;7(1):15-19. objective electroencephalography (eeg) recording is a long duration procedure that needs patient’s cooperation for device setup and performing the procedure. ...

We performed a sequence of tests on a partially water-saturated sand sample contained in an x-raytransparent aluminum pressure vessel that is conducive to x-ray computed tomography (CT) observation. These tests were performed to gather data for estimation of thermal properties of the sand/water/gas system and the sand/hydrate/water/gas systems, as well as data to evaluate the kinetic nature of ...

We have attempted to make the gas hydrate crystal in vegetable in order to extend the shelf life of fresh vegetable as preservation technique instead of freezing. As a result, it was confirmed that gas hydrate can be formed in onion tissue at 5 o C by pressurizing between 0.4 and 0.8 MPa Xe pressure. However, the detail conditions regarding to gas hydrate formation in vegetable tissue and their...

[1] We developed a multicomponent, multiphase, fluid and heat flow model to describe hydrate formation in marine sediments; the oneand two-dimensional model accounts for the dynamic effects of hydrate formation on salinity, temperature, pressure, and hydraulic properties. Free gas supplied from depth forms hydrate, depletes water, and elevates salinity until pore water is too saline for further...

Clathrate hydrates are crystalline compounds composed of hydrogen-bonded water molecules that form polyhedral cavities and trap small guest molecules such as methane, carbon dioxide, cyclopentane (CP), and tetrahydrofuran (THF). Understanding the formation and dissociation of clathrate hydrates is of significant importance to addressing some global challenges such as greenhouse gas mitigation a...

The mechanical properties of methane hydrate are important to the stability of borehole and methane extraction from a methane hydrate reservoir. In this study, a series of triaxial compression tests were carried out on laboratory-formed methane hydrate-ice mixtures with various methane hydrate contents. Axial loading was conducted at an axial strain rate of 1.33%/min and a constant temperature ...