Reaction of K2PdCl4 with Synthetic and Natural Nucleic Acids

Circular dichroism was used to study reaction of K₂PdCl₄ with polydeoxyribonucleotides and calf thymus DNA. The optical and structural characteristics of the molecular components were determined to show that K₂PdCl₄ reacts with natural and synthetic acids, producing profound rearrangements in their structure.     

Influence of Relative Air Humidity on Evaporation of Water–Ethanol Solution Droplets

Colloid Journal - Evaporation of droplets of water–ethanol solutions with different concentrations has been experimentally studied at different relative humidities of ambient air. High-speed...     

Late-Stage Transitional Boundary-Layer Structures. Direct Numerical Simulation and Experiment

This paper is devoted to direct comparisons of related, detailed experimental and numerical studies of the non-linear, late stages of laminar-turbulenttransition in a boundary layer including flow breakdown and the beginning offlow randomization. Preceding non-linear stages of the transition process arealso well documented and compared with previous studies. The experiments wereconducted with the help of a hot-wire anemometer. The numerical study wascarried out by direct numerical simulation (DNS) of the flow employing theso-called spatial approach. Both the experiments and the DNS were performed atcontrolled disturbance conditions with an excitation of instability waves inthe flat-plate boundary layer. In the two cases, the primary disturbanceconsists of a time-harmonic, two-dimensional Tollmien--Schlichting wave thathas a very weak initial spanwise modulation. Despite somewhat differentinitial disturbance conditions used in the experiment and simulation, thesubsequent flow evolution at late non-linear stages is found to be practicallythe same. Detailed qualitative and quantitative comparisons of theinstantaneous velocity and vorticity fields are performed for twocharacteristic stages of the non-linear flow breakdown: (i) “one-spike stage” and (ii) “three-spike stage.” The twoapproaches clearly show in detail the process of development of the Γ-structure, a periodical formation of ring-like vortices, the evolution of the surrounding flow field, and the beginning of flowrandomization. In particular, it is found experimentally and numerically thatthe ring-like vortices (associated with the well-known spikes) induce somerather intensive positive velocity fluctuations (positive spikes) in thenear-wall region which have the same scales as the ring-like vortices and propagate downstream with the same high (almost free-stream) speed. The positive spikes form a new high-shear layer in the near-wall region. In the experiment the induced near-wall perturbationshave a significant irregular low-frequency component. These non-periodicalmotions play an important role in the process of flow randomization and finaltransition to turbulence that starts under the ring-like vortices in thevicinity of the peak position. Received 13 December 2000 and accepted 30 October 2001     

String-inspired model for orbital excitations of glueballs

The relativistic string-inspired model of glueballs which contain two valence gluons connected by a straight-line string, is constructed. The model spectrum which consists of five Regge trajectories is compared with the experimental data.     

Integrability of fermionic string in superfield Hamiltonian approach

A model of a closed fermionic string (FS) is studied within the superfield canonical approach in the framework of which a general solution is found to Hamilton's equations of motion. An auxiliary spectral problem for the FS-theory is formulated and an infinite set of conservation laws is constructed. Also, a method is proposed for constructing classical analogues of vertex operators describing the FS-massless field coupling.     

Regenerative heat exchanger with a periodic change in the airflow direction for room ventilation

This paper presents the results of experimental research of heat transfer in air-to-air regenerative heat exchanger with periodic change of flow direction. The temperatures of the airflow and the material of regenerative packing in different sections have been obtained. The temperature efficiency of the heat exchanger has been determined at different flow rates. The developed mathematical model of the regenerative heat exchanger is described. It is shown that the model fairly well describes the experimental results. Based on numerical studies the dependence of thermal efficiency of the heat exchanger on the airflow rate is determined. It is shown that changing the ratio of the oppositely directed flow rates, it is possible to regulate the temperature of the air flowing into the room. The possibility of using the model for optimizing the operational and design parameters of heat exchanger is demonstrated.     

String-inspired model for orbital excitations of glueballs

The relativistic string-inspired model of glueballs which contain two valence gluons connected by a straight-line string, is constructed. The model spectrum which consists of five Regge trajectories is compared with the experimental data.