Jet and drops formation in electrohydrodynamic spraying of liquids. A systematic approach

 The surface of the liquid issuing from a capillary subjected to the electric stresses deforms to an elongated jet which disrupts to a series of droplets. In the paper the detailed experimental studies of jet and drop formation from liquid issuing from a capillary maintained at high voltage of positive or negative polarity have been reported. The forms of the jet and the way it disrupts into droplets have been classified into the modes of spraying. A definition of the mode of spraying and the criteria for the mode classification, based on the geometrical form of the meniscus, jet or drop formation are given. Received: 16 September 1997/Accepted: 15 November 1998     

Efficient synthesis of the core structure of muraymycin and caprazamycin nucleoside antibiotics based on a stereochemically revised sulfur ylide reaction

The reaction of protected uridine 5′-aldehydes with sulfur ylides has been reinvestigated. Further transformation of the resulting epoxide product provided a compound of which a single crystal for X-ray diffraction was obtained. As a consequence from the elucidated structure, the stereochemical configuration of the epoxide furnished by the sulfur ylide reaction was revised. Based on these results, an efficient synthesis of the core structure of the naturally occurring muraymycin and caprazamycin nucleoside antibiotics was developed.     

Suppression of Liquid-Liquid Phase Separation and Aggregation of Antibodies by Modest Pressure Application

The high colloidal stability of antibody (immunoglobulin) solutions is important for pharmaceutical applications. Inert cosolutes, excipients, are generally used in therapeutic protein formulations to minimize physical instabilities, such as liquid–liquid phase separation (LLPS), aggregation and precipitation, which are often encountered during manufacturing and storage. Despite their widespread use, a detailed understanding of how excipients modulate the specific protein-protein interactions responsible for these instabilities is still lacking. In this work, we demonstrate the high sensitivity to pressure of globulin condensates as a suitable means to suppress LLPS and subsequent aggregation of concentrated antibody solutions. The addition of excipients has only a minor effect. The high pressure sensitivity observed is due to the fact that these flexible Y-shaped molecules create a considerable amount of void volume in the condensed phase, leading to an overall decrease in the volume of the system upon dissociation of the droplet phase by pressure already at a few tens of to hundred bar. Moreover, we show that immunoglobulin molecules themselves are highly resistant to unfolding under pressure, and can even sustain pressures up to about 6 kbar without conformational changes. This implies that immunoglobulins are resistant to the pressure treatment of foods, such as milk, in high-pressure food-processing technologies, thereby preserving their immunological activity.     

Corona and back discharges in flue-gas simulating mixture

Results of spectroscopic investigations and current–voltage characteristics of electrical discharges between a needle and plate electrodes in a gas mixture simulating flue gases from coal fired power plants at atmospheric pressure are presented in the paper. In these investigations, back discharge was generated at the plate electrode covered with fly ash layer in order to simulate the conditions similar to those in electrostatic precipitators. To characterize the physical processes in back discharges, the emission spectra were measured and compared with those obtained for normal corona discharge generated in the same electrode configuration but with fly ash removed from the electrode. The emission spectra provide information on elemental and molecular composition of the layer. It was also shown that discharge characteristics in flue gas are quite different from those occurring in ambient air.     

Induced and coinduced Banach Lie–Poisson spaces and integrability

The Poisson induction and coinduction procedures are used to construct Banach Lie–Poisson spaces as well as related systems of integrals in involution. This general method applied to the Banach Lie–Poisson space of trace class operators leads to infinite Hamiltonian systems of k-diagonal trace class operators which have infinitely many integrals. The bidiagonal case is investigated in detail.     

Bethe Subalgebras in Hecke Algebra and Gaudin models

The generating function for elements of the Bethe subalgebra of the Hecke algebra is constructed as Sklyanin’s transfer-matrix operator for the Hecke chain. We show that in a special classical limit ${q \to 1}$ the Hamiltonians of the Gaudin model can be derived from the transfer-matrix operator of the Hecke chain. We construct a non-local analog of the Gaudin Hamiltonians in the case of the Hecke algebras.     

Properties of biomass vs. coal fly ashes deposited in electrostatic precipitator

This paper presents comparative experimental studies of the morphology and elemental composition of fly ash particles from coal- and biomass-fired boilers, deposited in each stage of 3-stage electrostatic precipitators (ESPs). It was shown that fly ash morphology, its physical properties, and the percentage of elements in the fly ash taken from each stage of ESP depend on the kind of fuel. The biomass fly ash contains many irregular large particles, which are pieces of unburned wood. Bulk density of biomass fly ash is on average lower than that of coal fly ash, and drastically decreases in the second and third stages of ESP. The resistivity, measured at electric field of 4 kV/cm, of fly ash from biomass-fired boilers is much lower than that from coal, and can be below 10² Ω m, whereas from coal, except the first stage, varies in the range from 10⁷ to 10¹⁰ Ω m. The low resistivity of coal fly ash in the first stage of ESP results from high carbon content, and of biomass is probably an effect of additional high percentage of potassium, calcium and sodium sulfates. The percentage of Si, Al, Na, Fe, and Ti in fly ash from coal-fired boilers is much higher than from biomass, and in the opposite, the percentage of Mg, K, Ca, Mn, Mo, S, Cl, and P in biomass ash exceeds that in coal fly ash. Potential detrimental effects of biomass combustion products (salts, acids, tar) leaving the boiler on the construction elements of the electrostatic precipitator, including electrodes and HV insulators have been discussed in this paper. It was concluded that the long-term effects of biomass co-firing on the electrostatic precipitator performance, including the collection efficiency, have not been sufficiently studied in the literature and these issues require further detailed investigations.     

A Simple Procedure for the Preparation of Chiral ‘Tris(hydroxymethyl)methane’ Derivatives

The aldol adducts 1a – 13a of R,R-2(tertbutyl)-6-methyl-1,3-dioxan-4-one (from 3-hydroxybutanoic acid) to aldehydes, single diastereoisomers obtained as described previously, are acetylated or benzoylated to the corresponding esters 1b – 5b and 6c – 13c , respectively, which in turn are reduced with LiAlH₄ to the title compounds 14 – 24 . The enantiomerically pure triols thus available may be useful as chiral building blocks, as auxiliaries for enantioselective reactions, and as center pieces for chiral dendrimers.