Nuclear track radiography of “Hot” aerosol particles

Nuclear track radiography was applied to identify aerosol “hot” particles which contain elements of nuclear fuel and fallout after Chernobyl NPP accident. For the determination of the content of transuranium elements in radioactive aerosols the measurement of the -activity of “hot” particles by SSNTD was used in this work, as well as radiography of fission fragments formed as a result of the reactions (n,f) and (γ,f) in the irradiation of aerosol filters by thermal neutrons and high energy gamma quanta. The technique allowed the sizes and alpha-activity of “hot” particles to be determined without extracting them from the filter, as well as the determination of the uranium content and its enrichment by ²³⁵U, ²³⁹Pu and ²⁴¹Pu isotopes. Sensitivity of determination of alpha activity by fission method is 5×10⁻⁶ Bq per particle. The software for the system of image analysis was created. It ensured the identification of track clusters on an optical image of the SSNTD surface obtained through a video camera and the determination of size and activity of “hot” particles.     

“Compensatory falsetto”: Effects on vocal quality

The term “compensatory falsetto”, for the purpose of this investigation, refers to the development of an abnormally high-pitched voice in the presence of laryngeal pathology where more socially acceptable lower pitched voice production is possible. The purpose of this investigation was to compare laryngeal compensations and their effects on objective measures of vocal function during production of compensatory falsetto voice. Eighteen patients with abnormally high-pitched voice in the presence of underlying laryngeal pathology were evaluated in the Department of Otolaryngology at the University of Miami School of Medicine from January 1988 through December 1992 and were diagnosed with “compensatory falsetto”. Vocal fold paralysis (n = 11) was the most common laryngeal pathology. Vibratory characteristics were evaluated through videostrobolaryngoscopic examination. Acoustic and aerodynamic parameters assessed included fundamental frequency, jitter rate, harmonic-to-noise ratio, glottal air flow, and maximum phonation time. Production of a higher-pitched voice appeared to improve glottic closure and decrease the amount of air loss during phonation. A corresponding increase in maximum phonation time and improvement in acoustic characteristics of jitter and harmonic-to-noise ratio was also observed.     

Determination of isotopic composition of plutonium in hot particles of the Chernobyl area

The knowledge of the isotopic composition of man-made transuranium elements (TUE) in the environmental samples is of great interest because, on the basis of these data, statements about the origin of the TUE can be made. One of the most radiotoxic elements released during reactor accidents and nuclear weapons tests was plutonium with the alpha emitters ²³⁸Pu, ²³⁹Pu, ²⁴⁰Pu, ²⁴²Pu and the beta-emitter ²⁴¹Pu which decays into ²⁴¹Am. The determination of plutonium in “hot” particles from the Chernobyl reactor was accomplished by means of solid state nuclear track detectors registering the alpha particles and by alpha spectroscopy after chemical treatment. Furthermore, in order to perform a complete analysis of the isotopic composition one of the “hot” particles has been investigated by resonance ionization mass spectrometry which possesses an excellent sensitivity and a good isotopic resolution.     

Deformed “commutative” Chern–Simons’ system

Noncommutative Chern–Simons’ system is non-perturbatively investigated at a full deformed level. A deformed “commutative” phase space is found by a non-canonical change between two sets of deformed variables of noncommutative space. It is explored that in the “commutative” phase space all calculations are similar to the case in commutative space. Spectra of its energy and angular momentum of the Chern–Simons’ system are obtained at the full deformed level. The noncommutative–commutative correspondence is clearly showed. Formalism for the general dynamical system is briefly presented. Some subtle points are clarified.     

“Slow” active control of combustion instabilities by modification of liquid fuel spray properties

This paper describes an experimental investigation of the feasibility of using “slow” active control approaches, which “instantaneously” change liquid fuel spray properties, to suppress combustion instabilities. The objective of this control approach was to break up the feedback between the combustion process heat release and combustor pressure oscillations that drive the instability by changing the characteristics of the combustion process (e.g., the characteristic combustion time). To demonstrate the feasibility of such control, this study used a proprietary fuel injector (Nanomiser^TM), which can vary its fuel spray properties, to investigate the dependence of acoustics–combustion process coupling, i.e., the driving of combustion instabilities, upon the fuel spray properties. This study showed that by changing the spray characteristics it is possible to significantly damp combustion instabilities. Furthermore, using combustion zone chemiluminescence distributions, which were obtained by Abel’s deconvolution synchronized with measured acoustic data, it has been shown that the instabilities were mostly driven midway between the combustor centerline and wall, a short distance downstream from the flame holder, where the mean axial flow velocity is approximately zero in the vortex near the flame holder. The results of this study strongly suggest that a “slow” active control system that employs controllable fuel injectors could be effectively used to prevent the onset of detrimental combustion instabilities.     

Feasibility of “intermittent” active control of combustion instabilities in liquid fueled combustors using a “smart” fuel injector

This paper describes an experimental investigation of the feasibility of an “intermittent” active control approach for suppressing combustion instabilities in liquid fueled combustors. The developed controller employs a “smart” fuel injector that can modify the spray properties in response to changes in combustor operating conditions. This action weakens or breaks up the coupling between the combustion process and combustor acoustic modes oscillations, thus preventing the excitation of large amplitude instabilities. This approach differs significantly from previously proposed active control methods, both in concept and implementation, as it requires only “intermittent” modification of the combustion process by a single control action as opposed to the continuous action required by most other active control methods. The “smart” fuel injector used in this study consisted of a double-staged, air-assisted atomizer in which counter swirling, primary (inner stage) and secondary (outer stage) air streams were supplied to the injector through separate sets of tangentially oriented orifices. Control of the ratio of air mass flow rates supplied to these two stages, by use of a diverter valve, resulted in significant changes in the spray shape and its axial, tangential, and radial velocity components. This variation in spray properties of the “smart” injector was characterized for different values of the inner to outer air flow rate ratio in cold flow tests with a PDPA system. These results were then correlated with the characteristics of the “intermittently” controlled combustor. Measured quantities included the instability amplitudes, axial dependence of the mean and oscillatory heat release amplitudes, and the characteristics of the recirculation zones, which were all shown to depend on the fuel spray properties. The results of this study demonstrate the feasibility of using “smart” fuel injectors with capabilities for varying the combustion process characteristics to reduce the amplitudes of detrimental combustion instabilities in real engines to acceptable levels.     

Modified Kolmogorov wave turbulence in QCD matched onto “Bottom-up” thermalization

We investigate modification of Kolmogorov wave turbulence in QCD calculating gluon spectra as functions of time in the presence of a low energy source which feeds in energy density in the infrared region at a time-dependent rate. Then considering the picture of saturation constraints as has been constructed in the “bottom-up” thermalization approach we revisit that picture for RHIC center-mass energy, W=130 GeV, and also extend it to LHC center-mass energy, W=5500 GeV, thus for two cases having an opportunity to calculate the equilibration time, τ_eq|therm, of the gluon system produced in a central heavy ion collision at mid-rapidity region. Thereby, at RHIC and LHC energies we can match the equilibration time, obtained from the late stage gluon spectrum of the modified Kolmogorov wave turbulence, onto that of the “bottom-up” thermalization and other evolutional approaches as well. In addition, from the revised “bottom-up” approach we find the gluon liberation coefficient to be on the average, ε0.81–1.06 at RHIC and ε0.50–0.56 at LHC. We also present other phenomenological estimates of τ_therm which, at QCD realistic couplings, yield 0.45–0.65 fmτ_therm0.97–2.72 fm at RHIC and 0.31–0.40 fmτ_therm0.86–2.04 fm at LHC. We show that the second upper-bounds of τ_therm in both cases are due to the late stage gluon spectrum of the original Kolmogorov wave turbulence in QCD, previously deduced with a low energy source which feeds in energy density at a constant rate. On the other hand, the lower-bounds and first upper-bounds of τ_therm are due to the late stage gluon spectrum of the modified QCD wave turbulence, deduced here at the specific time-dependent rate. In the latter case, at certain conditions, taking also into account both very small and realistic couplings we give estimates: 0.65 fmτ_therm1.29 fm at RHIC and 0.52 fmτ_therm1.16 fm at LHC, as well as at realistic couplings we find 0.53<τ_therm<0.7 fm at RHIC and 0.41<τ_therm<0.65 fm at LHC.     

Application of SSNTDs to investigations of radiation accident after-effects

Track methods and devices used for studies conducted after radiation accidents are considered. Solid State Nuclear Track Detectors (SSNTDs) are applied for measurements of contamination in soil, water, biological and other objects of alpha-emitting radionuclides, as well as for estimation of neutron doses by means accident dosimeters. Known radiation accidents (Chernobyl a.o.) and potential emergencies (sunken submarine “Komsomolets”, nuclear reactors) are discussed. Some result of SSNTD application at after-accident period are presented.     

Completeness of “good” Bethe ansatz solutions of a quantum-group-invariant Heisenberg model

The sl_q(2) quantum-group-invariant Heisenberg model with open boundary conditions is investigated by means of the Bethe ansatz. As is well known, quantum groups for q equal to a root of unity possess a finite number of “good” representations with non-zero q-dimension and “bad” ones with vanishing q-dimension. Correspondingly, the state space of an invariant Heisenberg chain decomposes into “good” and “bad” states. A “good” state may be described by a path of only “good” representations. It is shown that the “good” states are given by all “good” Bethe ansatz solutions with roots restricted to the first periodicity strip, i.e. only positive-parity strings (in the language of Takahashi) are allowed. Applying Bethe's string-counting technique completeness of the “good” Bethe states is proven, i.e. the same number of states is found as the number of all restricted paths on the sl_q(2) Bratteli diagram. It is the first time that a “completeness” proof for an anisotropic quantum-invariant reduced Heisenberg model is performed.     

Novel comprehension of “common path” principle

The idea of “common path” has been widely applied in optical instrument design for 30 years and even today. But the meaning of “common path” has not yet been explained clearly and sometimes confusion has been created. In this paper an “adaptive principle” is proposed and recommended on optical instrument system. It suggests that the designer not only arranges the measurement system to obtain measurement signal but also sets a channel to give prediction of noise or disturbance in real time or short term. Such a recommendation is based on the recent studies on nonlinear dynamics and atmospheric disturbance by means of experiments as well as theoretical analysis.     

K–K excitations on as “primary” superfields

We show that the K–K spectrum of IIB string on is described by “twisted chiral” superfields, naturally described in “harmonic superspace”, obtained by taking suitable gauge singlets polynomials of the D3-brane boundary superconformal field theory.To each p-order polynomial is associated a massive K–K short representation with states. The quadratic polynomial corresponds to the “supercurrent multiplet” describing the “massless” bulk graviton multiplet.     

A concise proof of the “geometric” construction of inertial manifolds

By employing the standard strong squeezing property, the “geometric” existence proof of Constantin et al. is considerably simplified, and the parallels between this and other methods thereby emphasised.     

Sorption Technique of Separation of Thallium-201 from Proton-Irradiated Thallium

A sorption technique is developed for radiochemical separation of thallium-201 from proton-irradiated targets of metallic thallium. The technique consists in separation of ²⁰¹Pb with the PbSO₄ precipitate followed by separation of ²⁰¹Pb and ²⁰¹Tl in the column with ammonium 12-molybdophosphate fixed in the matrix of porous Teflon (AMP-sorbent). The chemical yield of radiothalium is 98%, the duration of chemical procedures is 2.5 … 3 hours.     

TigerSHARC201在声纳信号处理系统中的应用

本文介绍了ADI公司最新数字信号处理器TS201的主要特点和基于TS201的VMEBus通用数字信号处理板的设计。文中较详细地分析了声纳信号处理系统的算法特点,系统的运算量和数据传输率的要求。然后给出了基于Quad-TS201 VMEBus通用数字信号处理板的具体声纳系统设计方案。该方案充分利用TS201强大的运算能力及高速数据吞吐率,以实现声纳的时空处理任务。该系统已研制成功,并在实际海上试验中得到应用。     

Functional Characteristics of a New Electrolarynx “Evada” Having a Force Sensing Resistor Sensor

Electrolarynxes have been used as one of the rehabilitation methods for laryngectomees. Earlier electrolarynxes could not alter frequency and intensity simultaneously during conversation. Recently, we developed an electrolarynx named “Evada” (prototype so far) using a force sensing resistor (FSR) sensor that can control both frequency and intensity simultaneously during conversation. Employing three types of electrolarynxes (Evada, Servox-inton, Nu-vois), this study was undertaken to examine the functional characteristics of Evada for the normal control group and for laryngectomess. Five laryngectomees and five normal adults were asked to express three sentences (declarative sentence, “You stay here.”, interrogative sentence, “You stay here?”, and imperative sentence, “You! Stay here.”) using three types of electrolarynxes. Frequency and intensity changes between the first and last vowels in the three sentences were calculated and analyzed statistically by paired t test. The frequency changes in the interrogative and imperative sentences were more prominent in Evada than in Servox-inton and Nu-vois. The intensity changes in the interrogative and imperative sentences were also more prominent in Evada than in Servox-inton and Nu-vois. Evada controls frequency and/or intensity by having the subject press the control button(s). Therefore, Evada appears to be better at producing intonation and contrastive stress than Nu-vois and Servox-inton.     

“Alternative medical therapy” use among singers: Prevalence and implications for the medical care of the singer

Singers are extremely conscious of health problems that affect their voices and well-being and often take an active role in seeking care for these problems. They frequently seek treatment from providers or with modalities considered “alternative” to traditional medical care. A survey of singers was completed to elucidate their attitudes and practices regarding “alternative modalities” of medical care. Frequently singers will self-medicate or take advice from people not well versed in the special needs of a professional voice user. They will fail to share this information with the physician when seeking “traditional” medical care. These practices may predispose the singer to suboptimal or even dangerous care. These results are discussed, as well as the implications for the medical physician treating the singer. The possible detrimental pharmacologic effects of “natural therapies” widely used by singers are presented, with special attention to the particular concerns for the professional singer     

Comparison of microphone and neck-mounted accelerometer monitoring of the performing voice

One method for monitoring individuals in live performances may be the use of vibration sensors, or accelerometers, rather than using microphones that pick up environmental noises as well as the vocal signals of interest. This study was concerned with a comparison of microphone and accelerometer monitoring of the amplitude characteristics of singers' voices. From the results obtained it appears that accelerometers are not applicable for monitoring amplitude characteristics of the voice, but are useful for periodicity measures. In addition, accelerometers may be of use in verifying the kinesthetic patterns sensed by a performer during the process of “singing into a mask” or producing the singer's “ring.”     

Spectral emissivity modeling of steel 201 during the growth of oxidation film over the temperature range from 800 to 1100 K in air

This study explores the spectral emissivity modeling of steel 201 during the growth of oxidation film over the temperature range from 800 to 1100 K at 1.5 μm. The radiance coming from the specimen is received by an InGaAs photodiode detector. The specimen temperature is obtained by averaging the two platinum–rhodium thermocouples, which are tightly welded in the front surface of specimen near the measuring area viewed by the detector. The variation of spectral emissivity with the temperature is studied at a given heating time. The variation of spectral emissivity with the heating time is evaluated at a definite temperature. The strong oscillations of spectral emissivity are observed and discussed in detail, which originate from the interference effect between the radiation stemming from the oxidization film on the specimen surface and the radiation coming from the specimen surface. The measurement uncertainties of spectral emissivity contributed only by the surface oxidization are about 3.2–14.1%. At a given heating time, the variation of spectral emissivity with the temperature abides well by a simple analytic functional form. And at a definite temperature, the variation of spectral emissivity with the heating time can also be well reproduced by fitting except for the periodical oscillations.     

Using plastic track detectors to solve radiation safety problems at nuclear reactor facilities

Three options of the method to determine microconcentrations of fissile materials in water solutions are developed. They utilize plastic track detectors to measure concentrations. The options are as follows a “wet” method, “thin-layer inorganic sorbent-plastic track detectors”, and a method of selective extraction and coprecipitation. These methods are used to check up fuel cladding integrity at the research reactor IVV-2M and liquid radioactive waste contamination by uranium and plutonium at the Beloyarskaya Nuclear Power Plant (BNPP).