Influence of Pretreatment of Expanded Graphite on Its Sorption Properties with Respect to Petroleum

Petroleum sorption on expanded graphite prepared from residual graphite hydrosulfate at 300-900°C was studied as influenced by pretreatment of the sorbent with water.     

Stabilization of Graphite Nitrate by Intercalation of Organic Compounds

New thermally stable intercalation compounds of graphite were obtained by the further intercalation of a series of organic compounds into graphite nitrate. The stabilization is explained by the formation of hydrogen bonds between the protonated form of the modifying substance and neutral surrounding molecules.     

Influence Exerted by Pyrite Impurity in the Initial Graphite on Properties of Residual Graphite Hydrosulfates

The influence exerted by the particle size and the distribution of sol impurities in the initial graphite, and also by pyrite additives, on the properties of residual graphite hydrosulfates synthesized by oxidation in the CrO₃-H₂SO₄ system was studied.     

Sorption of Industrial Oil by Expanded Graphite

Sorption of industrial oil by expanded graphite prepared from residual graphite hydrosylfate at 300-900°C was studied. The sorption isotherms of both neat oil and oil from its aqueous suspension were measured. The sorption capacity for oil was studied as influenced by the specific surface area and specific volume of expanded graphite sorbent.     

Synthesis and Thermal Swelling of Residual Graphite Hydrosulfates Obtained Using the Na2Cr2O7-H2SO4 System

The influence exerted by the conditions of synthesis of residual graphite hydrosulfate in a system constituted by concentrated sulfuric acid and saturated aqueous solution of sodium dichromate on the properties of the final product was studied in a wide range of reagent consumptions. The swelling coefficient and the loss of the product were analyzed as functions of the intercalate content in the product.     

Propagation of three-dimensional waves generated by a traveling region of time-periodic pressure in a rotating layer of uniform fluid

The effect of rotation of a uniform fluid on the kinematic characteristics of the waves generated by the motion of a variable-intensity pressure region over its surface is investigated. All the possible types of wave fields for gyroscopic modes are analyzed, and the dependence of the shape of the leading fronts and the angular width of the wave zones of the wave systems excited on the model parameters is investigated.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.3, pp. 110–116, May–June, 1992.     

Model for the Thermal Expansion of Modified Graphite Nitrates

The thermal expansion of modified graphite nitrates was studied under close-to-equilibrium conditions. A model was proposed based on the expansion of a cavity in the sample similar to a Griffith crack. In accord with this model, the increase in the volume of the sample is proportional to the sixth power of the temperature due to the synergistic action of three factors: 1) accumulation of gas in the cavity, 2) increase in the temperature, and 3) decrease in the limiting pressure that the cavity can withstand without expanding.     

Synthesis and Properties of Expandable Residual Graphite Hydrosulfate Obtained in the System CrO3-H2SO4

The fundamental aspects of synthesis of expandable residual graphite hydrosulfate with the use of an oxidizing system CrO₃-H₂SO₄ at ultralow consumption of the reagents and their separate introduction into the reaction mass were studied. The dependence of the expansion ratio of the samples obtained on the content of intercalant and expansion temperature was analyzed.     

Sorption of Oil by Swollen Graphite: Contributions of Specific Surface Area and Specific Volume

Sorption of heavy oil by swollen graphites obtained from residual graphite hydrosulfate at 300- 900°C was studied. The dependence of the sorption capacity for oil on the specific surface area and specific volume of the swollen graphite sorbent was analyzed.     

The development of three-dimensional waves generated by perturbations of varying intensity in a flow of continuously stratified fluid

An analysis is made in the linear formulation of the three-dimensional structure of unsteady waves created in a flow of continuously stratified fluid by a region of pressures which are harmonic with respect to time.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 71–77, November–December, 1984.