Mechanisms of sibilant noise formation observed during forced exhalation of a healthy person

Wheezes of the forced exhalation (FEW) are important for the diagnostics of bronchial obstruction, however, mechanisms of FEW noise formation have not been clearly identified. The objective of the study is statistical modeling of mechanisms of FEW noise formation in the selected subset of health volunteers. FEW were identified by experts with the use of the spectrogram. The frequencies of FEW with maximal amplitudes were determined in four time fractions. In the assumption of air incompressibility for Weibel morphometry of the bronchial tree considering a decreased section of the respiratory tract at the forced exhalation, the average values of proportionality coefficients between the correlations of the linear velocity of air flow and the average diameters of the respiratory tract, and the maximal frequencies of FEW were calculated. Obtained values of the coefficients have been compared with predictable empirical models     

Analytische Aspekte der Oxydation organischer Stickstoffverbindungen mit Chromsäure. IV

Zusammenfassung Die schon früher vorgeschlagene Halbmikromethode zur Bestimmung der N-N-Gruppierung wurde an einer Reihe aromatischer Azoverbindungen erprobt. Sie beruht auf der Oxydation der Substanz mit einem Chromsäure-Schwefelsäure-Gemisch in einer geschlossenen Apparatur. Die Azogruppen werden als elementarer Stickstoff abgespalten, der im Azotometer gesammelt und gemessen wird. Durch die Rücktitration der unverbrauchten Chromsäure kann außerdem die Oxydationszahl der untersuchten Substanz bestimmt werden.

---

Summary The semimicro method previously suggested for the determination of the N-N-grouping was tested on a number of aromatic azo compounds. It is based on oxidation of the sample with a chromic-sulfuric acid mixture in a closed apparatus. The azo groups are split off as elementary nitrogen which is collected in an azotometer and measured. In addition the oxidation number of the material being studied can be found by backtitration of the unconsumed chromic acid.

---

Résumé On a mis à l'épreuve la semimicrométhode déjà préconisée auparavant, pour le dosage du groupe N-N, sur une série de composés azo-aromatiques. Elle repose sur l'oxydation de la substance par un mélange d'acide chromique et d'acide sulfurique, en système clos. Les groupes azoïques se trouvent dissociés à l'état d'azote élémentaire que l'on récupère et que l'on dose dans l'azotomètre. On peut déterminer, de plus, l'indice d'oxydation de la substance étudiée par titrage en retour de l'acide chromique non consommé.

---

---

III. Mitteilung siehe 1.     

Study of the formation mechanisms of forced expiratory wheezes in a healthy person when breathing gas mixtures of different density

The aim of the study is to specify the localization and formation mechanisms of forced expiratory wheezes (FEWs) in the bronchial tree. Statistical modeling of FEW spectral parameters has been performed, which were recorded above the lower sections of the lungs to the right and left, as well as over the trachea, from a sampling of 25 volunteers who breathed gases of different density. It was established that the highest amplitude FEWs formed closer to the trachea, and the lowest, in more distally located levels of the bronchial tree. The lower the density of the gas, the closer to the trachea the formation of mid-frequency FEWs occurs. For earlier high-frequency FEWs, an indirect dependence of their peak frequency on the Reynolds number was revealed. Turbulent-flow-induced forced oscillations and, in particular, vortex shedding are the probable formation mechanism for some of the FEWs.     

Gamma-ray bursts from evaporating primordial black holes

It is believed that the detection of gamma-ray bursts from evaporating primordial black holes is highly improbable in the near future since the expected photon flux, consisting mainly of photons with energies ? GeV, is too low. Contrary to this point of view, we show that a large fraction of the black hole power at the final stage of evaporation (the last 10³ s) can be liberated as a burst of soft γ-ray emission of duration 10^?1–10³ s and luminosity 10²⁸–10³¹ erg/s in the energy range 0.1–1 MeV. According to our calculations of the black hole evaporation rate (within the Standard Model of elementary particles), when the black hole temperature exceeds approximately 10 GeV, the charged particle outflow from a black hole forms a well-defined plasma and can be described in the hydrodynamic approximation. In this case more than half of the rest energy of a black hole can be converted into soft gamma-rays due to the presence of the magnetic field with energy density comparable to that of charged particles. We consider various mechanisms leading to such transformation and estimate their efficiency. It is shown that, at least, some of the gamma-ray bursts detected by BATSE can be associated with evaporating black holes.     

Pro duction of Exotic Nuclei in Low-Energy Multi-Nucleon Transfer Reactions

Multinucleon transfer processes in low-energy heavy ion collisions open a new field of research in nuclear physics, namely, production and studying properties of heavy neutron rich nuclei. This not-yet-explored area of the nuclear map is extremely important for understanding the astrophysical nucleosynthesis and the origin of heavy elements. Beams of very heavy U-like ions are needed to produce new long-living isotopes of transfermium and superheavy elements located very close to the island of stability.The calculated cross sections are high enough to perform the experiments at available accelerators.Beams of medium-mass ions (such as 136Xe, 192Os, 198Pt) can be used for the production of neutron rich nuclei located along the neutron closed shell N = 126 (the last waiting point) having the largest impact on the astrophysical r-process. The Low-energy multinucleon transfer reactions is a very efficient tool also for the production and spectroscopic study of light exotic nuclei. The corresponding cross sections are 2 or 3 orders of magnitude larger as compared with high energy fragmentation reactions.     

Effect of ultrasonic oscillations on the fluidity of heavy oil products at low temperatures

We develop a laboratory setup to estimate the force of rotation of a metal branch pipe in a viscoelastic medium. We show that 2-min action of shearing ultrasonic oscillations (frequency, 32.5 kHz; specific power, no more than 0.008 W/cm²) reduces by 17% the static limit of fluidity brought to an initial temperature of ì-100 fuel oil cooled to −15°C in the wall layer of a rotating branch pipe. We obtain a linear regression dependence between the ratio of the threshold force of the onset of branch pipe motion to the consumption current of the ultrasonic transducer and the fuel temperature.     

Model with uniquely deducible parameters for the combined analysis of two resonating vibrational states. Anharmonic resonances in molecules of asymmetric-gyroscope type

A model of an effective Hamiltonian with parameters that are uniquely deducible from the spectrum for the combined analysis of the rotational structure of two resonating vibrational states is proposed and validated. Anharmonic resonances in molecules of asymmetric-gyroscope type are considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 108–112, February, 1982.     

High-order anharmonicity parameters in various representations of the diatomic potential function and exact relations between spectroscopic constants. application to the co molecule

Closed formulae for Born—Oppenheimer anharmonicity parameters a_n in terms of isotopically invariant constants U_mj are derived for Dunham, Simons—Parr—Finlan, Ogilvie—Tipping and Thakkar representations and are applied to the CO molecule. Models for a fit of vibration—rotation and pure rotational transitions based on the exact relations U_mj = f(U_k,o, U_k-1.1) and U_mj = α(U_k,1, U_k,2) are discussed.     

On localization of wheezing respiratory sounds in human lungs by means of intensimetric processing of signals detected on the chest surface

We obtain a set of equations for determining the distance from the chest surface to various sources (monopole, dipole, transverse quadrupole) of wheezing sounds in human lungs. During testing, we experimentally determined anatomically correct estimates for the distances to sources of wheezing sounds in the frequency range of 100–500 Hz. We demonstrate the possibility of resolving the distances to sources of wheezing sounds with different peak frequencies. We analyze the main limitations of the method.