Specific Features of Cellulose Phase Transition via Knecht Additive Compound

The capability of cotton and wood cellulose in the common and microcrystalline forms to transform into cellulose-II under the action of 68-69% HNO₃ was studied. The influence of temperature on the course of the phase transition in cellulose samples differing in origin and morphological structure and the dynamics of concomitant hydrolytic degradation and esterification of these materials were studied.     

Basicity and mechanism of transmission of electronic effects of substituents in the series of 2-amino-5-aryl-1,3,4-thiadiazoles

The basicity of 2-amino-5-aryl-1,3,4-thiadiazoles was studied. A correlation was obtained between the pK_BH+ values of the compounds and the constants of the substituents. It was shown that the electronic effects of the substituents in the phenyl ring are transmitted both on account of conjugation and by an induction mechanism.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 267–270, February, 1987.     

Synthesis and mass-spectrometric study of 2-amino- and 2-chloro-5-aryl-1,3,4-thiadiazoles

The cyclization of aldehyde thiosemicarbazones with ferric chloride yielded 2-amino-5-aryl-1,3,4-thiadiazoles, forming 2-chloro-5-aryl-1,3,4-thiadiazoles in the Sandmeyer reaction. The mass-spectrometric behavior of the 2-amino- and 2-chloro-5-aryl-1,3,4-thiadiazoles was studied; the typical routes of fragmentation characteristic of each group of compounds were found.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1416–1419, October, 1986.     

Depassivation of Ion-Exchange Membranes in Electrodialysis

Procedures were developed to prevent precipitation on the ion-exchange membrane surface in demineralization of natural hydrocarbonate water by electrodialysis.     

Status of the polarized ions source for the JINR accelerator complex

The project assumes the design and construction of a universal high-intensity source of polarized deuterons (protons) using a charge-exchange plasma ionizer. The output D ⁺↑ (H ⁺↑) current of the source is expected to be at a level of 10 mA. The polarization will be up to 90% of the maximal vector (±1) for D ⁺↑ (H ⁺↑) and tensor (+1, ?2) for D ⁺↑ polarization. Realization of the project is carried out in close cooperation with INR of the RAS (Moscow). The equipment available from the CIPIOS ion source (IUCF, Bloomington, USA) is partially used for the Dubna setup. The new source at the JINR Nuclotron accelerator facility will make it possible to increase the polarized deuteron beam intensity up to the level of 10¹⁰ d/pulse. The first results of the source of polarized atoms testing are presented.     

Combination of oxidative and hydrolytic functions of nitric acid in production of enterosorbents based on carboxylated microcrystalline cellulose

A single-stage procedure was developed for preparing carboxylated microcrystalline cellulose from native cellulose in 45–55% nitric acid acting as a deposited form of catalyst of cellulose oxidation, nitrogen(IV) oxide, and as a selective reagent partially hydrolyzing cellulose.     

Nitric Acid Procedure for Production of Powdered Cellulose II Forms with Various Morphologies and Comparison of Their Structural and Sorption Characteristics

A two-stage procedure for production of powdered cellulose II, based on polymorphous transformation of native cellulose I and hydrolytic dispersion of the fiber with a single reagent, nitric acid, was proposed.     

The features of nitric acid ‘mercerization’ of cellulose

Transformation of native cellulose species into cellulose-II polymorph through the additive Knecht compound formed under the action of 68.5% nitric acid has been studied. Probable causes of peculiar temperature effects in the course of phase transformations taking place in cellulose of various origin, crystallite dispersity, or morphologic structure are discussed. The processes of hydrolytic destruction and esterification of starting materials during their mercerization by this non-traditional agent at 20 °C and 0 °C are quantitatively characterized. In the case of mercerization of wood microcrystalline cellulose at 20 °C a decrystallizing effect due to side reactions of partial nitration is noted.     

The RHIC polarized source upgrade

The RHIC polarized H^? ion source is being upgraded to higher intensity and polarization for use in the RHIC polarization physics program at enhanced luminosity RHIC operation. The higher beam intensity will allow reduction of the longitudinal transverse beam emittance at injection to AGS to reduce polarization losses in AGS. There is also a planned RHIC luminosity upgrade by using the electron beam lens to compensate the beam-beam interaction at collision points. This upgrade is also essential for future BNL plans for a high-luminosity electron-proton (ion) Collider eRHIC. The basic limitations on the high-intensity H^? ion beam production in charge-exchange collisions of the neutral atomic hydrogen beam in the Na-vapor jet ionizer cell were experimentally studied.     

Current Density Distribution as Parameter of Electroionite Process

The effect of artificially preset current density distribution in an electroionite apparatus on the ex-tent of water demineralization is considered. The change in the extent of demineralization on varying the distribution of one, the same current between parts of apparatus at the inlet, outlet of diluate is explained.