| 1. |
- Al-Rabiah, Abdulrahman A., et al.
(författare)
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Effect of styrene-butadiene-styrene copolymer modification on properties of Saudi bitumen
- 2016
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Ingår i: Petroleum Science and Technology. - : Informa UK Limited. - 1532-2459 .- 1091-6466. ; 34:4, s. 321-327
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Tidskriftsartikel (refereegranskat)abstract
- This research investigates the effects of styrene-butadiene-styrene (SBS) copolymer and other plastomers on the behavior of Saudi bitumen. Three bitumen samples, extracted from three Saudi oil refineries, namely Ras Tanura, Riyadh, and Yanbu, were used in this study. The bitumen samples were mixed with different modifiers in various compositions, forming polymer modified bitumens (PMBs). Elasticity parameters, such as ductility and elastic recovery were measured and evaluated. Characteristics of raw bitumen were analyzed to observe the compatibility of bitumen with SBS and plastomers. Bitumen samples were suitable for SBS modification and SBS PMBs showed superior elasticity behaviors compared to plastomer blends.
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| 2. |
- Kutcherov, Vladimir G., 1955-, et al.
(författare)
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Properties and phase behavior of Shtokman gas condensate at high pressure
- 2019
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Ingår i: Petroleum science and technology. - : TAYLOR & FRANCIS INC. - 1091-6466 .- 1532-2459. ; 37:9, s. 1099-1105
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Tidskriftsartikel (refereegranskat)abstract
- Thermal conductivity, heat capacity per unit volume and phase behavior of Shtokman gas condensate were investigated at high pressure up to 1800 MPa in the temperature interval of 245-373 K using the transient hot-wire method. No crystallization was observed in the sample. The glass transition process in the Shtokman gas condensate takes place in the thermobaric interval which lies outside the range of temperatures and pressures corresponding to the production and transport of the gas condensate.
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| 3. |
- Lopes, Melina Savioli, et al.
(författare)
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Reduction in the amount of sulfur in waste oil using reactive molecular distillation
- 2021
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Ingår i: Petroleum Science and Technology. - : Informa UK Limited. - 1091-6466 .- 1532-2459. ; 39:13-14, s. 471-483
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Tidskriftsartikel (refereegranskat)abstract
- Petroleum, contains proportions of contaminants such as sulfur, nitrogen, oxygen, and metals, such as nickel, iron, copper, sodium, and vanadium. Particularly, contaminants containing sulfur cause problems during handling, transportation, and the use of the their derivatives. This work had the goal of cracking the heavy crude oil molecules by reacting these molecules with tetralin and simultaneously promoting the separation of the low-mass and high-mass fractions, aiming to obtain a product of high value. The process to be studied is Reactive Molecular Distillation (RMD). It was developed at the laboratory LDPS-FEQ-UNCAMP, in order to perform the molecular distillation with chemical reaction using tetralin, which, at high temperatures (210 to 330 °C) and high vacuum (10-3 mmHg), suffers the cracking of molecules, providing protons that help the disaggregation of asphaltene; consequently, the residues will suffer physicochemical alterations and, therefore, the reduction in the amount of sulfur in the oil waste. The sample to be studied is a petroleum waste, named JU 560 °C. This oil is a residue from the vaccuum column of an oil distillery. With the processing of petroleum waste JU 560 °C with 5% of tetralin, a reduction of 49% in the sulfur content of the original sample was achieved.
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| 4. |
- Bongini, L, et al.
(författare)
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Freezing immunoglobulins to see them move
- 2004
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 101:17, s. 6466-6471
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Tidskriftsartikel (refereegranskat)abstract
- The issue of protein dynamics and its implications in the biological function of proteins are arousing greater and greater interest in different fields of molecular biology. In cryo-electron tomography experiments one may take several snapshots of a given biological macromolecule. In principle, a large enough collection of snapshots of the molecule may then be used to calculate its equilibrium configuration in terms of the experimentally accessible degrees of freedom and, hence, to estimate its potential energy. This information would be crucial in order to analyze the biological functions of biomolecules by directly accessing the relevant dynamical indicators. In this article, we analyze the results of cryo-electron tomography experiments performed on monoclonal murine IgG2a antibodies. We measure the equilibrium distribution of the molecule in terms of the relevant angular coordinates and build a mechanical model of the antibody dynamics. This approach enables us to derive an explicit expression of the IgG potential energy. Furthermore, we discuss the configuration space at equilibrium in relation to results from other techniques, and we set our discussion in the context of the current debate regarding conformation and flexibility of antibodies.
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