bluuebunny/crossref_metadata_2025 huggingface dataset:
Forces on permeable conductors in magnetic fields
Authors: Casperson Lee W.
Published: July 2002

It is often implied that the force density formula dF/dV=J×B is all that is required to calculate the force that would be experienced by any stationary current-carrying medium in a region of space containing a magnetic field. However, representations of this formula are not all compatible, and the methods of applying such formulas when the conductor or surrounding medium have permeabilities different from vacuum are not widely known. The simplest case that one might consider is that of a current-carrying wire in an otherwise uniform field. It appears that the experimental measurements corresponding to such a situation have not been carried out for permeable media, and these results are reported here. The permeability and current can cause substantial changes in the field distribution from its background form, but the total force per unit length on the wire remains compatible with the formula I×B0, with I being the conduction current and B0 being the flux density that was present before the permeable current-carrying wire was introduced.
Incomplete descriptions and relevant entropies
Authors: Balian Roger
Published: July 2002

Statistical mechanics relies on the complete although probabilistic description of a system in terms of all its microscopic variables. Its object is to derive from this microscopic description the static and dynamic properties for some reduced set of variables. The elimination of the irrelevant variables is guided by the maximum entropy criterion, which produces the least biased probability law consistent with the available information about the relevant variables. This approach defines relevant entropies which measure the missing information associated with the variables retained in the incomplete description. The relevant entropies depend not only on the state, but also on the coarseness of the reduced description of the system. Their use sheds light on questions such as the second law, both in equilibrium and in irreversible thermodynamics, the projection operator method of statistical mechanics, Boltzmann’s H-theorem, and spin-echo experiments.
Development of wide-band middle ear transmission in the Mongolian gerbil
Authors: Overstreet Edward H. , Ruggero Mario A.
Published: July 2002

Stapes vibrations were measured in deeply anesthetized adult and neonatal (ages: 14 to 20 days) Mongolian gerbils. In adult gerbils, the velocity magnitude of stapes responses to tones was approximately constant over the entire frequency range of measurements, 1 to 40 kHz. Response phases referred to pressure near the tympanic membrane varied approximately linearly as a function of increasing stimulus frequency, with a slope corresponding to a group delay of 30 μs. In neonatal gerbils, the sensitivity of stapes responses to tones was lower than in adults, especially at mid-frequencies (e.g., by about 15 dB at 10–20 kHz in gerbils aged 14 days). The input impedance of the adult gerbil cochlea, calculated from stapes vibrations and published measurements of pressure in scala vestibuli near the oval window [E. Olson, J. Acoust. Soc. Am. 103, 3445–3463 (1998)], is principally dissipative at frequencies lower than 10 kHz. Conclusions: (a) middle-ear vibrations in adult gerbils do not limit the input to the cochlea up to at least 40 kHz, i.e., within 0.5 oct of the high-frequency cutoff of the behavioral audiogram; and (b) the results in both adult and neonatal gerbils are inconsistent with the hypothesis that mass reactance controls high-frequency ossicular vibrations and support the idea that the middle ear functions as a transmission line.
Frequency-to-electrode allocation and speech perception with cochlear implants
Authors: McKay Colette M. , Henshall Katherine R.
Published: July 2002

The hypothesis was investigated that selectively increasing the discrimination of low-frequency information (below 2600 Hz) by altering the frequency-to-electrode allocation would improve speech perception by cochlear implantees. Two experimental conditions were compared, both utilizing ten electrode positions selected based on maximal discrimination. A fixed frequency range (200–10 513 Hz) was allocated either relatively evenly across the ten electrodes, or so that nine of the ten positions were allocated to the frequencies up to 2600 Hz. Two additional conditions utilizing all available electrode positions (15–18 electrodes) were assessed: one with each subject’s usual frequency-to-electrode allocation; and the other using the same analysis filters as the other experimental conditions. Seven users of the Nucleus CI22 implant wore processors mapped with each experimental condition for 2-week periods away from the laboratory, followed by assessment of perception of words in quiet and sentences in noise. Performance with both ten-electrode maps was significantly poorer than with both full-electrode maps on at least one measure. Performance with the map allocating nine out of ten electrodes to low frequencies was equivalent to that with the full-electrode maps for vowel perception and sentences in noise, but was worse for consonant perception. Performance with the evenly allocated ten-electrode map was equivalent to that with the full-electrode maps for consonant perception, but worse for vowel perception and sentences in noise. Comparison of the two full-electrode maps showed that subjects could fully adapt to frequency shifts up to ratio changes of 1.3, given 2 weeks’ experience. Future research is needed to investigate whether speech perception may be improved by the manipulation of frequency-to-electrode allocation in maps which have a full complement of electrodes in Nucleus implants.
Frequency-dependent attenuation-compensation functions for ultrasonic signals backscattered from random media
Authors: Oelze Michael L. , O’Brien William D.
Published: July 2002

Estimations of scattering parameters, such as average scatterer diameter, from rf signals backscattered from random media (tissues) are made from the frequency dependence of the rf signal. The frequency dependence of the rf signal backscattered from the medium is seen in the normalized power spectrum. The normalized power spectrum is found by taking the squared magnitude of the Fourier transform of the rf signal gated over a region of interest and dividing by some reference spectrum. If the medium has a frequency-dependent attenuation then the shape of the normalized power spectrum will be affected by the frequency-dependent attenuation and the time duration of the gated signal. Not accounting for the frequency-dependent attenuation leads to poor estimations of scatterer parameters. Larger attenuation and longer time gates give poorer estimates of scatterer parameters without attenuation compensation. Several attenuation-compensation functions have been used to account for the attenuation losses to the normalized power spectrum. A new attenuation-compensation function is proposed and compared with the other attenuation-compensation routines. The new attenuation-compensation function is shown to give improved estimates over previous attenuation-compensation functions for scatterers that follow a Gaussian form factor.
Cooperative interaction as the physical basis of the negative stiffness in hair cell stereocilia
Authors: Iwasa K. H. , Ehrenstein G.
Published: July 2002

A recent report confirmed that stiffness of the stereocilia can be negative, as predicted by the Howard–Hudspeth model. According to this model, the mechanotransducer channel’s gating not only reduces the stereociliary stiffness, but can alter its sign as well. The basic assumptions of this model do not include cooperativity in channel gating. Here we consider two possible explanations for the observed negative stiffness. If the stereocilia have a special structure so that microscopic displacement can be imposed on each channel by controlling the bending of the bundle, negative stiffness can occur without channel cooperativity. If such a microscopic condition cannot be imposed by a macroscopic manipulation, an additional physical process, such as cooperativity in channel gating, is required to explain negative stiffness.
Efficient adaptive procedures for threshold and concurrent slope estimates for psychophysics and speech intelligibility tests
Authors: Brand Thomas , Kollmeier Birger
Published: July 2002

The minimum standard deviations achievable for concurrent estimates of thresholds and psychometric function slopes as well as the optimal target values for adaptive procedures are calculated as functions of stimulus level and track length on the basis of the binomial theory. The optimum pair of targets for a concurrent estimate is found at the correct response probabilities p1=0.19 and p2=0.81 for the logistic psychometric function. An adaptive procedure that converges at these optimal targets is introduced and tested with Monte Carlo simulations. The efficiency increases rapidly when each subject’s response consists of more than one statistically independent Bernoulli trial. Sentence intelligibility tests provide more than one Bernoulli trial per sentence when each word is scored separately. The number of within-sentence trials can be quantified by the j factor [Boothroyd and Nittrouer, J. Acoust. Soc. Am. 84, 101–114 (1988)]. The adaptive procedure was evaluated with 10 normal-hearing and 11 hearing-impaired listeners using two German sentence tests that differ in j factors. The expected advantage of the sentence test with the higher j factor was not observed, possibly due to training effects. Hence, the number of sentences required for a reliable speech reception threshold (approximately 1 dB standard deviation) concurrently with a slope estimate (approximately 20%–30% relative standard deviation) is at least N=30 if word scoring for short, meaningful sentences (j≈2) is performed.
Depth-pressure relationships in the oceans and seas
Authors: Leroy Claude C. , Parthiot François
Published: July 2002

Two sets of equations, covering all world oceans and seas, are presented to calculate pressure from depth for the computation of sound speed, and depth from pressure for use in ocean engineering. They are based on the algorithm of UNESCO 1983 [N. P. Fofonoff and R. C. Millard, Jr., Unesco Tech. Papers in Mar. Sci. No. 44 (1983)], and on calculations from temperature and salinity profiles. The pressure to depth conversion is presented first. The equations can be used in those cases where the desired accuracy is reduced to ±0.8 m. The equations to convert depth to pressure provide an overall accuracy between ±8000 Pa and ±1000 Pa. This leads to errors in sound speed consistently smaller than ±0.02 m/s. The discussion, and comparisons with results and other formulas, suggest that the new equations are a substantial improvement on the previous simplified ones, which should now be abandoned.
Input mobilities and power flows for edge-excited, semi-infinite plates
Authors: Kauffmann Christiaan
Published: July 2002

The basis of this paper is a paper by E. Eichler [J. Acoust. Soc. Am. 36, 344–348 (1964)], which deals with the response of a semi-infinite plate, driven by a uniform, time-harmonic load applied at a finite part of its free edge. Eichler used Fourier transforms in the edge direction and obtained closed form integral expressions for the plate response. The present paper provides full details of the analysis (some of them not previously published) and gives corrections to some of Eichler’s results. New, closed form integral expressions for the power flows are derived. Numerical results for 0<ka<10 are presented for the case of uniform excitation over an excitation area of length 2a (k is the structural wave number). A simple physical classification facilitates the interpretation of the results: (i) ka≪1: point excitation; (ii) ka→∞: line excitation (beam mode); and (iii) ka=O(1): modulation due to interference effects at intermediate frequencies. Additionally, the case of N point loads (forces, tangential moments, and normal moments) with nonuniform spacing and arbitrary amplitude and phase distributions is discussed. Numerical results for the power flow include the coupling term between two point loads at separation s and are presented for 0<ks<10. Depending on the type of excitation interference shows up as strong, intermediate or weak modulation.
Time-average temperature distribution in a thermoacoustic stack
Authors: Mozurkewich George
Published: July 2002

The three-dimensional time-average temperature distribution in a pore of a thermally isolated thermoacoustic stack is calculated. A boundary-value problem is formulated in the acoustic and short-stack approximations from the equation of conservation of energy using literature results for the time-average energy flux. In the central region of the pore, the solution for the time-average temperatures of the wall, Tw, and of the gas along its center line, Tg, share a common profile, linear in the axial coordinate, z. Near the pore ends, where the energy flux approaches zero, the axial gradient of Tg approaches the critical temperature gradient over a distance of order the acoustic displacement amplitude. The axial gradient of Tw approaches zero over a much smaller distance, provided the wall has small thermal conductivity. The transverse heat-flux density, q, is nonzero only near pore ends. Under certain conditions, q=h1(Tg−Tw), where h1 is proportional to the thermal conductivity of the gas divided by the thermal penetration depth. The constant of proportionality, of order unity, depends on pore width and Prandtl number. Results agree favorably with recently published numerical calculations.
Comparisons of measured and predicted acoustic fluctuations for a 3250-km propagation experiment in the eastern North Pacific Ocean
Authors: Colosi John A. , Scheer Edward K. , Flatté Stanley M. , Cornuelle Bruce D. , Dzieciuch Matthew A. , Munk Walter H. , Worcester Peter F. , Howe Bruce M. , Mercer James A. , Spindel Robert C. , Metzger Kurt , Birdsall Theodore G. , Baggeroer Arthur B.
Published: July 2002

During the Acoustic Engineering Test (AET) of the Acoustic Thermometry of Ocean Climate (ATOC) program, acoustic signals were transmitted from a broadband source with 75-Hz center frequency to a 700-m-long vertical array of 20 hydrophones at a distance of 3252 km; receptions occurred over a period of six days. Each received pulse showed early identifiable timefronts, followed by about 2 s of highly variable energy. For the identifiable timefronts, observations of travel-time variance, average pulse shape, and the probability density function (PDF) of intensity are presented, and calculations of internal-wave contributions to those fluctuations are compared to the observations. Individual timefronts have rms travel time fluctuations of 11 to 19 ms, with time scales of less than 2 h. The pulse time spreads are between 0 and 5.3 ms rms, which suggest that internal-wave-induced travel-time biases are of the same magnitude. The PDFs of intensity for individual ray arrivals are compared to log-normal and exponential distributions. The observed PDFs are closer to the log-normal distribution, and variances of log intensity are between (3.1 dB)2 (with a scintillation index of 0.74) for late-arriving timefronts and (2.0 dB)2 (with a scintillation index of 0.2) for the earliest timefronts. Fluctuations of the pulse termination time of the transmissions are observed to be 22 ms rms. The intensity PDF of nonidentified peaks in the pulse crescendo are closer to a log-normal distribution than an exponential distribution, but a Kolmogorov–Smirnov test rejects both distributions. The variance of the nonidentified peaks is (3.5 dB)2 and the scintillation index is 0.92. As a group, the observations suggest that the propagation is on the border of the unsaturated and partially saturated regimes. After improving the specification of the ray weighting function, predictions of travel-time variance using the Garrett–Munk (GM) internal-wave spectrum at one-half the reference energy are in good agreement with the observations, and the one-half GM energy level compares well with XBT data taken along the transmission path. Predictions of pulse spread and wave propagation regime are in strong disagreement with the observations. Pulse time spread estimates are nearly two orders of magnitude too large, and Λ–Φ methods for predicting the wave propagation regime predict full saturation.
Thermal diffusion and mixture separation in the acoustic boundary layer
Authors: Swift G. W. , Spoor P. S.
Published: July 2002

Oscillating thermal diffusion in a sound wave in a mixture of two gases is remarkably effective for separating the components of the mixture. We consider this separation process in boundary-layer approximation, with zero temperature gradient and zero concentration gradient along the direction of sound propagation. In the boundary layer, the combination of thermal diffusion with the oscillating temperature gradient and oscillating velocity gradient leads to second-order time-averaged fluxes of the two components of the mixture in opposite directions, parallel to the wave-propagation direction. The oscillating thermal diffusion also adds to the dissipation of acoustic power in the boundary layer, modifying thermal-relaxation dissipation but leaving viscous dissipation unchanged.
Inter-relationship between different psychoacoustic measures assumed to be related to the cochlear active mechanism
Authors: Moore Brian C. J. , Vickers Deborah A. , Plack Christopher J. , Oxenham Andrew J.
Published: July 2002

The active mechanism in the cochlea is thought to depend on the integrity of the outer hair cells (OHCs). Cochlear hearing loss is usually associated with damage to both inner hair cells (IHCs) and OHCs, with the latter resulting in a reduction in or complete loss of the function of the active mechanism. It is believed that the active mechanism contributes to the sharpness of tuning on the basilar membrane (BM) and is also responsible for compressive input–output functions on the BM. Hence, one would expect a close relationship between measures of sharpness of tuning and measures of compression. This idea was tested by comparing three different measures of the status of the active mechanism, at center frequencies of 2, 4, and 6 kHz, using subjects with normal hearing, with unilateral or highly asymmetric cochlear hearing loss, and with bilateral loss. The first measure, HLOHC, was an indirect measure of the amount of the hearing loss attributable to OHC damage; this was based on loudness matches between the two ears of subjects with unilateral hearing loss and was derived using a loudness model. The second measure was the equivalent rectangular bandwidth (ERB) of the auditory filter, which was estimated using the notched-noise method. The third measure was based on the slopes of growth-of-masking functions obtained in forward masking. The ratio of slopes for a masker centered well below the signal frequency and a masker centered at the signal frequency gives a measure of BM compression at the place corresponding to the signal frequency; a ratio close to 1 indicates little or no compression, while ratios less than 1 indicate that compression is occurring at the signal place. Generally, the results showed the expected pattern. The ERB tended to increase with increasing HLOHC. The ratio of the forward-masking slopes increased from about 0.3 to about 1 as HLOHC increased from 0 to 55 dB. The ratio of the slopes was highly correlated with the ERB (r=0.92), indicating that the sharpness of the auditory filter decreases as the compression on the BM decreases.
Long time-base observations of surf noise
Authors: Deane Grant B.
Published: July 2002

A year of surf noise observations in the very near shore region of La Jolla Shores beach are presented. Ambient sound levels and surface wave height were recorded for 9 min every hour from July 1997 through June 1998 at a monitoring station located 360 m seaward of the beach in 8-m deep water. Sound segments that were dominated by the noise from breaking surf formed the basis of a correlation analysis between surf noise level and wave height, wave period, wind speed, and mean water depth. The analysis shows that surf noise is primarily determined by wave height, and scales approximately with the wave height squared. The surface wave energy flux onto the beach also scales with wave height squared, leading to the conclusion that the conversion of the mechanical energy of the surface wave field into noise energy is approximately constant. In fact, the ratio of noise energy to surface wave energy flux varies by up to a factor of 3 over the range of energy fluxes considered (100–3000 W per m).
A Unified Derivation of Constitutive Relations for Irrecoverable Deformation
Authors: Berg Charles A.
Published: July 2002

Constitutive relations are derived for isotropic materials in which local thermodynamic equilibrium obtains and for which the internal energy of each element depends only upon the volume and entropy of the element. The basis of the derivation is the principle that the material possesses a non-negative entropy production function which depends upon the rates of deformation. Results include constitutive relations for viscous, plastic, and viscoplastic deformation.
Experimental Study of the Flow of Two-Phase Systems at High Temperature
Authors: Axelrad D. R.
Published: July 2002

This paper deals with the description of an apparatus employed for the performance of mechanical tests on specimens of 2-phase materials. In particular, a new optical-photoelectric method is described in some detail, which has been used for the direct measurement of deformations in the high temperature field (up to 2000°C). The strain-time graphs obtained from isothermal short-time creep tests of some of these materials are discussed.
Dynamical Aspects of Viscoelasticity
Authors: Davis Julian L.
Published: July 2002

This paper is concerned with some aspects of the dynamic response of a three-dimensional linear viscoelastic medium to prescribed boundary conditions. The constitutive equations, expressed in operator form, are applied to a three-dimensional continuum and are combined with the equations of motion to yield a system of linear partial differential equations. This system may be expressed in terms of a scalar and vector potential and parameters called “generalized velocities c1* and c2*” (operators describing the properties of the medium). The free radial vibrations of a viscoelastic sphere and spherical shell are worked out for the prescribed boundary conditions. In particular the phase velocity is obtained as a function of the wave number and a complex frequency. The wave number is obtained from the roots of a transcendental equation. The free longitudinal vibrations of a viscoelastic cylinder are determined by solving the equations for the scalar and vector potentials with the appropriate boundary conditions. The phase velocity is obtained for the Voigt and Maxwell models. In addition, asymptotic results are obtained which reduce to either the thin rod or the Pochhammer approximation.
Mechanical and Optical Characterization of Plasticized Polyvinyl Chloride
Authors: Daniel I. M.
Published: July 2002

Mechanical and birefringent properties of plasticized polyvinyl ehloride in the glass transition region were determined by means of quasistatic tests at different temperatures and sinusoidal oscillation tests at room temperature. In the former method, mechanical creep and photocreep tests were conducted at temperatures ranging from −80 to 115°F. The method of reduced variables (temperature-time equivalence principle) was used to obtain continuous curves for relaxation modulus and stress fringe value corresponding to room temperature and extending up to 24 decades of time. The resulting curves show a broad transition region for the material. The shift function was plotted versus temperature and was found to be about the same for both mechanical and optical properties. Short-time (dynamic) properties obtained by the temperature-time equivalence principle were compared with those obtained at room temperature by direct sinusoidal oscillation tests at different frequencies. The complex modulus and complex stress fringe value were determined as functions of frequency and converted to a relaxation modulus and stress fringe value as functions of time by means of an approximate interrelationship. The validity of the temperature-time equivalence principle in this case was proven by the good agreement between these results and those obtained from creep tests at different temperatures.
Propagation of One-Dimensional Stress Discontinuities in Homogeneous and Inhomogeneous Viscoelastic Media
Authors: Reiss Edward L.
Published: July 2002

The propagation of small amplitude stress discontinuities in linear viscoelastic media with differential stress-strain laws is considered. The theory of weak solutions is used to determine the curves of discontinuity and the jumps in the stress and the velocity and their successive derivatives on the discontinuity. A Taylor series expansion is then used to approximate the stress and the velocity behind and sufficiently near the discontinuity. These results are applied to study the propagation of longitudinal impact waves in semi-infinite and finite viscoelastic rods.
Transients in Model Viscoelastic Materials
Authors: Gruntfest I. J. , Mueller G. E.
Published: July 2002

The dynamic behavior of a homogeneous slab subjected to a short pressure pulse on one face is explored from a simple rheological point of view. The analysis is one dimensional, but involves two strain modes in the material. The early response is shown to be controlled by the bulk viscosity which influences the distortion and attenuation of propagating disturbances. In particular, the peak stress at interior points is shown to be very sensitive to the duration of the pressure. This result is quite different from that usually applied in the analysis of impact data in which it is assumed that the controlling differential equations are hyperbolic and that the density pressure relation is not time dependent. It is also more compatible with some of the experimental results. Criteria for mechanical similarity are described which may be useful in the design and development of systems subjected to impacts. The uniaxial deformation generated in this type of experiment is contrasted with the uniaxial load condition generated in the usual tensile test. In the present case, not only the wave propagation is distinctive, but the tendency toward strain homogeneity and strain stability can also be greatly enhanced. This is likely to be relevant to the understanding of material-forming processes.
The Response Functions of an Anisotropic Linear Viscoelastic Material
Authors: Hayes M. A. , Morland L. W.
Published: July 2002

A series of tests is proposed to determine the possible 36 independent relaxation moduli of a homogeneous linear anisotropic viscoelastic body. The complete series comprises three simple shear tests, and 21 tests of a single type described as pure compression which employ essentially the same apparatus.
Relaxation Properties of Polyester-Based Polyurethane Under Small Deformations Superposed on Large Deformations
Authors: Wang T. T. , Klosner J. M.
Published: July 2002

An investigation has been carried out to determine the extensional mechanical behavior of a viscoelastic material when it is subject to an infinitesimal displacement field superposed on a finite steady deformation. Experiments were conducted on a thin strip of a polyester-based polyurethane at a temperature of 77°F (±3°F). It is shown that the relaxation modulus of this material can be expressed as a product of two functions, one of which depends only upon the elongation ratio and the other only upon time. This form is applicable for basic-state elongation ratios 1⩽λ⩽1.2 and for a period of 2 hr. It is noted that the separable form is highly suspect for longer time intervals.
Multiple Integral Description of the Nonlinear Viscoelastic Behavior of a Clay Soil
Authors: Adeyeri Joseph B. , Krizek Raymond J. , Achenbach Jan D.
Published: July 2002

The results of a series of uniaxial compression creep and relaxation tests on cylindrical specimens of a remolded clay are reported. A multiple integral theory is used to describe the observed nonlinear mechanical behavior over a range of water contents and over a time range from a few seconds to beyond 10,000 min. Although the single integral representation, that is, linear viscoelastic theory, is found to be inadequate for characterizing the mechanical behavior of the soil, except perhaps for very small strains and very short times, the double and triple integral representations show quite good agreement with experimental data.
On the Consideration of Dynamic Effect in Folding Deformation of a Layered Viscoelastic Medium in Compression
Authors: Ghosh B.
Published: July 2002

Previous works on folding deformation of a layered viscoelastic medium in compression preclude the consideration of dynamic effect as the contribution due to this effect is assumed to be negligibly small because of sufficiently slow deformation rate. In this discussion the dynamic effect is included in finding a modified expression for the dominant wavelength and the analysis is carried through to deduce criteria for the existence of the dominant wavelength under known prestress conditions. A workable estimate to detect the circumstances within the framework of classical linear theory of elasticity under which the results obtained by quasi-static and dynamic considerations differ significantly is constructed in later part. The presence of such significant deviation of values indicates the deformation rate is not sufficiently slow and therefore the inertia term characterizing the dynamic effect can not be neglected. To elucidate further a graph giving the values of the ratio of the dominant wavelengths in two considerations is provided in the end.
Stress Relaxation of Viscoelastic Material
Authors: Hlaváček B. , Stanislav J. F. , Seyer F. A.
Published: July 2002

The stress relaxation of viscoelastic material after cessation of steady-state flow has been investigated. A method is proposed that allows fairly accurate prediction of the shear stress component, P12(t), as well as the first normal stress component, P11–P22(t), for a relatively wide range of time and shear rates. The main advantage of the method is in its simplicity, which could make it suitable for engineering calculations.
A New Oscillating Element Instrument for Viscometric Studies of Biological Fluids
Authors: Berger S. A. , Chow F. , Singer J. R.
Published: July 2002

A new type of viscometer is described, whose basic principle is the measurement of the damping of a fluid on a small resonant element. The major advantages of this instrument are that only small samples are required for analysis and that rapid cyclical measurements are possible. The viscometer can be used with Newtonian and non-Newtonian fluids. In the present paper a theoretical analysis for a Newtonian fluid only is given. The theory is shown to predict the measured damping characteristics well for a number of test fluids.
An Empirical Constitutive Model for Polymer Solutions
Authors: Pearson Glen , Middleman Stanley
Published: July 2002

Constitutive relations generally require a large set of fluid relaxation times to provide an accurate fluid description. In situations involving the solution of the dynamic equations of flow simultaneously with the constitutive relation, the use of a single relaxation time model is desirable because of the time consuming nature of the numerical solution schemes. This work presents a single relaxation time fluid model, obtained by empirically modifying the existing form of the Meister model. The empiricisms take the form of two functions of deformation rate, chosen so the model will predict quantitatively the time to maximum overshoot and the magnitude of the maximum overshoot in transient shear stress for a “start-up” experiment. The modified model compares very well to transient and steady data for five polymer solutions and to the predictions of the Carreau Model B.
Experimental Tests of Some Integral Rheological Relations
Authors: Kearsley E. A. , Zapas L. J.
Published: July 2002

Some new rheological relations are derived for the BKZ fluid in shear. These relations all involve integrals rather than derivatives of stress measurements. For suddenly applied constant rate of shear, several relations are found connecting (a) time-dependent normal-stress at one shear rate to integrals of time-dependent shear-stress over shear-rate and time, (b) time-dependent shear-stress to integrals of time-dependent normal-stress over shear-rate and time, (c) an integral over time of normal-stress to an integral over shear rate of steady-state shear-stress, and (d) an integral over time of shear-stress to an integral over shear-rate of steady-state normal-stress. For sudden cessation of steady shear a rheological relation is found connecting an integral over time of shear-stress to an integral over shear-rate of normal-stress. These relations are tested with data from measurements on PIB solutions. The results suggest that time-dependent normal-stress data are not reliable. Within this limitation, the results are consistent with the requirements of a BKZ fluid. A rheological relation appropriate to single-integral rate-type constitutive equations is examined also and found to be inconsistent with the data, as is the van Es and Christensen test.
Prevalence of hypertension among the indigenous population in North‐East India: Is this a consequence of “nutritional transition”?
Authors: Ghosh Sudipta , Peseyie Viserano
Published: August 2022

Objectives

This article aims to understand the influence of residential status on the prevalence of cardiovascular disease (CVD) risk factors among adult Angami Naga of Nagaland.

Methods

A total number of 194 (100 rural and 94 urban) adult Angami Naga participated in the study. Blood pressure, both systolic and diastolic, was measured for each participant. Nutritional status was evaluated through body mass index. Metabolic health was measured through waist circumference, waist‐hip ratio and percent body fat (%BF). Multiple regression analysis was done to examine the influence of residential status and other bio‐social factors on the prevalence of obesity and hypertension.

Results

Results indicate high prevalence of systolic hypertension among urban residents, in both males (29.6%Urban vs. 20.4%Rural; p > .05) and females (17.4%Urban vs. 11.6%Rural; p > .05), with gender inequality favoring females. Similar trend was observed in diastolic hypertension as well. On the other hand, obesity was found to be greater in rural males (8.3%Urban vs.10.2%Rural; p = .002), and urban females (11.6%Urban vs. 3.5%Rural; p > .05). However in %BF, only negligible percentages of urban females (2.3%Urban vs. 0.0%Rural; p > .05) were found to be moderately overweight or obese and no males were found to be overweight. Further, regression analyzes indicate that age, sex, and residential status are the most important (p < .001) causal factors behind the prevalence of obesity and hypertension among the Angami Naga.

Conclusions

It was observed that elderly urban males were the most susceptible section of this community in developing CVD risk factors related vulnerabilities. However, we propose understanding this prevalence from an evolutionary approach of physiological mechanism toward nutritional transition in Angami Naga, like many other indigenous populations of northeast India.
Septin‐5 and ‐7‐IgGs: Neurologic, Serologic, and Pathophysiologic Characteristics
Authors: Hinson Shannon R. , Honorat Josephe A. , Grund Ethan M. , Clarkson Benjamin D. , Miske Ramona , Scharf Madeleine , Zivelonghi Cecilia , Al‐Lozi Muhammad Taher , Bucelli Robert C. , Budhram Adrian , Cho Tracey , Choi Ellie , Grell Jacquelyn , Lopez‐Chiriboga Alfonso Sebastian , Levin Marc , Merati Melody , Montalvo Mayra , Pittock Sean J. , Wilson Michael R. , Howe Charles L. , McKeon Andrew
Published: August 2022

Background and Objectives

We sought to determine clinical significance of neuronal septin autoimmunity and evaluate for potential IgG effects.

Methods

Septin‐IgGs were detected by indirect immunofluorescence assays (IFAs; mouse tissue and cell based) or Western blot. IgG binding to (and internalization of) extracellular septin epitopes were evaluated for by live rat hippocampal neuron assay. The impact of purified patient IgGs on murine cortical neuron function was determined by recording extracellular field potentials in a multielectrode array platform.

Results

Septin‐IgGs were identified in 23 patients. All 8 patients with septin‐5‐IgG detected had cerebellar ataxia, and 7 had prominent eye movement disorders. One of 2 patients with co‐existing septin‐7‐IgG had additional psychiatric phenotype (apathy, emotional blunting, and poor insight). Fifteen patients had septin‐7 autoimmunity, without septin‐5‐IgG detected. Disorders included encephalopathy (11; 2 patients with accompanying myelopathy, and 2 were relapsing), myelopathy (3), and episodic ataxia (1). Psychiatric symptoms (≥1 of agitation, apathy, catatonia, disorganized thinking, and paranoia) were prominent in 6 of 11 patients with encephalopathic symptoms. Eight of 10 patients with data available (from 23 total) improved after immunotherapy, and a further 2 patients improved spontaneously. Staining of plasma membranes of live hippocampal neurons produced by patient IgGs (subclasses 1 and 2) colocalized with pre‐ and post‐synaptic markers. Decreased spiking and bursting behavior in mixed cultures of murine glutamatergic and GABAergic cortical neurons produced by patient IgGs were attributable to neither antigenic crosslinking and internalization nor complement activation.

Interpretation

Septin‐IgGs are predictive of distinct treatment‐responsive autoimmune central nervous system (CNS) disorders. Live neuron binding and induced electrophysiologic effects by patient IgGs may support septin‐specific pathophysiology. ANN NEUROL 2022;92:1090–1101
Electronic Character of α,3‐Dehydrotoluene Intermediates Generated from Isolable Allenyne‐Containing Substrates
Authors: Xu Qian , Hoye Thomas R.
Published: August 2022

We report here the generation of α,3‐dehydrotoluenes, a relatively rare subset of reactive intermediates of the dehydroaromatic family, from isolable allenynes. The substructure motif in the allenyne substrates is distinct from, and complementary to, those found in Myers‐Saito/Schmittel‐type cycloisomerizations. The reactions reported here give rise to product profiles that provide insight about the electronic nature (i.e., diradical vs. zwitterion vs. cyclic allene) of the particular isomeric DHT(s) that is(are) produced under different reaction conditions differing most significantly in the polarity of the reaction solvent. One example also revealed previously unobserved carbene‐like reactivity of the DHT.
Open‐Bandgap Graphene‐Based Field‐Effect Transistor Using Oligo(phenylene‐ethynylene) Interfacial Chemistry
Authors: Kim Kyung Ho , Seo Sung Eun , Park Chul Soon , Kim Soomin , Lee Soohyun , Ryu Choong‐Min , Yong Dongeun , Park Yoo Min , Kwon Oh Seok
Published: August 2022

Organic interfacial compounds (OICs) are required as linkers for the highly stable and efficient immobilization of bioprobes in nanobiosensors using 2D nanomaterials such as graphene. Herein, we first demonstrated the fabrication of a field‐effect transistor (FET) via a microelectromechanical system process after covalent functionalization on large‐scale graphene by introducing oligo(phenylene‐ethynylene)amine (OPE). OPE was compared to various OICs by density functional theory simulations and was confirmed to have a higher binding energy with graphene and a lower band gap than other OICs. OPE can improve the immobilization efficiency of a bioprobe by forming a self‐assembly monolayer via anion‐based reaction. Using this technology, Magainin I‐conjugated OGMFET (MOGMFET) showed a high sensitivity, high selectivity, with a limit of detection of 100 cfu mL−1. These results indicate that the OPE OIC can be applied for stable and comfortable interfacing technology for biosensor fabrication.
An Activatable and Reversible Virus‐Mimicking NIR‐II Nanoprobe for Monitoring the Progression of Viral Encephalitis
Authors: Chen Hua‐Jie , Qin Ying , Wang Zhi‐Gang , Wang Lei , Pang Dai‐Wen , Zhao Dongbing , Liu Shu‐Lin
Published: August 2022

Viral encephalitis is an inflammatory disease of the brain parenchyma and caused by various viral infections. In vivo monitoring of the progression of viral infections can aid accurate diagnosis of viral encephalitis and effective intervention. We developed an activatable and reversible virus‐mimicking near‐infrared II nanoprobe consisting of an Fe2+‐coordinated, viral protein‐decorated vesicle encapsulating PbS quantum dots with a 1300 nm fluorescence emission. The probe can cross the blood–brain barrier and monitor real‐time changes in reactive oxygen and nitrogen species concentrations during viral infection by tuning the quenching level of quantum dots and regulating the fusion–fission behavior of vesicles via changes in Fe oxidation state. This switching strategy reduces background noise and improves detection sensitivity, making this nanoprobe a promising imaging agent for dynamic visualization of viral encephalitis and future clinical applications.
Online administration of the ADOS for research with adolescents and adults in response to the pandemic
Authors: Eigsti Inge‐Marie , Thomas Rebecca P. , Stabile Mackenzie , Mohan Anusha , Dieckhaus Mary F. S. , Crutcher Jason , Taverna Elise , Fein Deborah A.
Published: August 2022

This study evaluates an online ADOS‐2 Module 4 administration. Adolescents and adults with (n = 24; 7 females) and without (n = 13; 5 females) a history of autism spectrum disorder (ASD) completed the ADOS‐2 Module 4 via videoconference. Parents or caregivers completed the Parent/Caregiver Form of the Vineland Adaptive Behavior Scales and the Achenbach Adult Behavior Checklist. The ADOS‐2 was reviewed and scored by five trained clinicians and supervised by a senior clinician with established research reliability. The autistic group's scores differed on ADOS total (Calibrated Severity Score, WPS instrument) and domain scores, KSADS domain scores, and Achenbach T‐scores. Inter‐rater reliability was “moderate” (κ = 0.732), and percentage item‐wise agreement was r = 0.69. The online ADOS‐2 showed significant convergence with parent‐reported assessments of ASD‐relevant symptoms and characteristics, suggesting it was a valid assessment. While any online assessments must be used with caution, results suggest that the approach described here could have sufficient validity and reliability to fill the urgent need to assess and evaluate ASD symptomatology, as one component of a thorough clinical evaluation of ASD‐related behaviors.

Lay Summary

In this exploratory study, we asked whether it was possible to give the ADOS‐2 to adolescents and adults in a completely online way. Results showed that expert clinicians agreed on 69% of ADOS‐2 items; also, participants with autism had higher scores on all parts of the ADOS‐2. The online ADOS‐2 scores had strong and significant relationships with parents' reports of friendship and social skills. While we need more research that tests this method, this way of doing the ADOS‐2 online may be useful for clinicians and researchers who have an urgent need to evaluate autism during the pandemic.
Multiple rib fractures confused with loss of lung volume on chest X‐ray
Authors: Hirata Risa , Tago Masaki , Tago Motoko
Published: August 2022

A 90‐year‐old woman with osteoporosis and no recent injury history visited the hospital for a regular checkup. Chest X‐ray showed a loss of right upper lung volume. Although we suspected pulmonary parenchymal or pleural disease, computed tomography revealed multiple rib fractures on the right side, which caused thoracic deformation.
Adducing Knowledge Capabilities of Instrumental Techniques Through the Exploration of Heterostructures’ Modification Methods
Authors: Underwood Timothy M. , Robinson Ross S.
Published: August 2022

The ongoing evolution of technology has facilitated the global research community to rapidly escalate the constant development of novel advancements in science. At the forefront of such achievements in the field of photocatalysis is the utilisation, and in oftentimes, the adaptation of modern instrumentation to understand photo‐physical properties of complex heterostructures. For example, coupling in‐situ X‐ray Raman scattering spectroscopy for real‐time degradation of catalytic materials.
Diagnostic value of ultrasound‐guided transbronchial lung biopsy in peripheral tuberculous pulmonary lesions
Authors: Zou Xingwu , Zhu Yanling , Hu Qin , Qi Qi , Hua Haibo , Fei Fan , Cai Qingshan
Published: August 2022

Background

To investigate the diagnostic value of bronchial ultrasound‐guided transbronchial lung biopsy (EBUS‐TBLB) in tuberculous peripheral pulmonary lesions.

Methods

A total of 770 patients who completed CT imaging and ultrasound bronchoscopy were retrospectively analyzed. All patients underwent biopsy sampling as well as alveolar lavage under the guidance of ultrasound. Pathological analysis and molecular biological detection of pulmonary tuberculosis were performed in both pathological tissues and bronchoalveolar lavage fluid (BALF), and the diagnostic positive rate and diagnostic sensitivity were statistically analyzed.

Results

Of the 44 patients who were found to have lesions by EBUS‐TBLB, 26 patients were able to achieve a definite diagnosis of PPLs, with an overall diagnostic yield of 59.1%. Of the 33 patients with all diagnosed benign lesions, 22 were diagnosed with active pulmonary tuberculosis with the diagnostic yield of 66.7%. Among above 22 cases, the overall positive rate of BALF diagnosis was as high as 95.6%, and the highest diagnostic rate of a single test was BALF XpertMTB/RIF, 59.1%. Compared with pathological tissues, the diagnostic positive rate of BALF as a diagnostic specimen was higher (p < .05). In addition, the diagnostic yield of EBUS‐TBLB in pulmonary tuberculosis was not affected by patient's age, lesion extent size, EBUS probe position, presence or tracheal grade, or characteristics of lesions (all p > .05).

Conclusion

Transbronchial radial ultrasound‐guided lung biopsy of tuberculous PPLs possesses higher diagnostic rate, fewer complications and less interference, exerts potential application value in the diagnosis of tuberculous peripheral pulmonary lesions.
Prediction of soil water storage using temporal stability in different landscape positions on the northern loess plateau, China
Authors: Li Xuezhang , Shao Ming'an , Xu Xianli
Published: August 2022

Soil water storage (SWS) dynamics are affected by many factors in semiarid regions such as the Loess Plateau. Spatiotemporal variation of SWS varies greatly with different landscape positions due to the rolling and fragmented terrain landscape of the Loess Plateau. However, information on the SWS and its temporal stability at different landscape positions is lacking. In this study, hillslope, dam land and gully landscape positions were selected in a typical small watershed in the Loess Plateau. A soil water observation belt with 28 sample locations was set up at each landscape position, and temporal stability analysis was conducted using SWS data of 12 sampling events. The results showed that the variation characteristics of profile SWS are influenced by landscape position. The persistence of spatial SWS patterns in different landscape positions increases with the increase of soil depth. On each landscape position, representative locations can accurately predict their SWS based on temporal stability analysis. Moreover, the stability of SWS at the representative locations was more important than its content during the prediction process. The dominant factors that lead to the difference of temporal stability characteristics in different landscape positions varied with the change in soil depths. The results provide an important basis for vegetation reconstruction and water management in small Loess Plateau watersheds.