A new technique for the measurement of low fluid velocities

1964 ◽  
Vol 20 (2) ◽  
pp. 183-192 ◽  
Author(s):  
M. Gaster
Keyword(s):  
Free Convection ◽  
Mean Value ◽  
New Technique ◽  
Mean Velocity ◽  
Flowing Fluid ◽  
Fluid Velocities ◽  
New Instrument ◽  
The Mean ◽  
A New Technique

A new instrument for measuring the velocities of particles suspended in a flowing fluid is described. The instrument is linear and is therefore capable of measuring the mean velocity in a fluctuating stream, even when these fluctuations are greater than this mean value. This particular instrument was developed for free convection work where the velocities to be measured were in the range + k 0.2 in./sec to − 0.2 in./sec, but there seems to be no reason why this range could not be considerably extended.

Matrixplasty for the Treatment of Severe Incurved Toenail with Growth Plate Deformity

2012 ◽  
Vol 102 (3) ◽  
pp. 198-204
Author(s):  
J.-Young Kim
Keyword(s):  
Growth Plate ◽  
Clinical Results ◽  
New Technique ◽  
Partial Removal ◽  
Edge Angle ◽  
Results Of Treatment ◽  
The Mean ◽  
A New Technique ◽  
Ingrown Toenails

Background: Severely incurved toenails are accompanied by deformity of the toenail growth plate. In such a condition, partial removal of the nail and nail bed and simple unfolding of the nail itself frequently result in the recurrence of symptoms. We sought to design and develop a new technique for the treatment of incurved toenail with growth plate deformity and to report the results of treating this disease entity. Methods: Forty consecutive patients (52 cases) underwent treatment of symptomatic incurved toenails with a new technique named matrixplasty. The mean ± SD patient age was 40.3 ± 18.9 years. Last follow-up was at a mean ± SD of 18.0 ± 1.3 months. An American Orthopedic Foot and Ankle Society (AOFAS) forefoot hallux score was assigned, and patients were evaluated before treatment and at last follow-up. Patient satisfaction and the recurrence rate of the deformity were evaluated. For evaluation of improvement in toenail shape, the center to edge angle of the toenail was measured before treatment and at last follow-up. The complication rate was also evaluated. Results: All of the ingrown toenails healed, and the nail deformities were corrected within 3 weeks after the procedure. None of the incurved toenails had recurred by last follow-up. The mean pretreatment AOFAS forefoot hallux score was 72.9, and it improved to 99.6 by last follow-up (P < .001). Every patient was very satisfied or satisfied with the results of treatment. The mean ± SD center to edge angle of the toenail improved from 53.3° ± 9.5° to 15.3° ± 5.2° by last follow-up (P < .001). Minor paronychia, which was managed with local wound dressing and oral antibiotics, was identified in four cases. No other complication was identified. Conclusions: Matrixplasty showed excellent clinical results in the treatment of severe incurved toenail, and this newly developed procedure showed improvement of the deformed toenail and its growth plate. (J Am Podiatr Med Assoc 102(3): 198–204, 2012)

scholarly journals Acceleration in turbulent channel flow: universalities in statistics, subgrid stochastic models and an application

2013 ◽  
Vol 721 ◽  
pp. 627-668 ◽  
Author(s):  
Rémi Zamansky ◽  
Ivana Vinkovic ◽  
Mikhael Gorokhovski
Keyword(s):  
Stochastic Model ◽  
Channel Flow ◽  
Scaling Law ◽  
Stochastic Modelling ◽  
Turbulent Channel Flow ◽  
Mean Value ◽  
Mean Velocity ◽  
Wall Distance ◽  
Eddy Simulation ◽  
The Mean

AbstractThis paper focuses on the characterization and the stochastic modelling of the fluid acceleration in turbulent channel flow. In the first part, the acceleration is studied by direct numerical simulation (DNS) at three Reynolds numbers (${\mathit{Re}}_{\ast } = {u}_{\ast } h/ \nu = 180$, 590 and 1000). It is observed that whatever the wall distance is, the norm of acceleration is log-normally distributed and that the variance of the norm is very close to its mean value. It is also observed that from the wall to the centreline of the channel, the orientation of acceleration relaxes statistically towards isotropy. On the basis of dimensional analysis, a universal scaling law for the acceleration norm is proposed. In the second part, in the framework of the norm/orientation decomposition, a stochastic model of the acceleration is introduced. The stochastic model for the norm is based on fragmentation process which evolves across the channel with the wall distance. Simultaneously the orientation is simulated by a random walk on the surface of a unit sphere. The process is generated in such a way that the mean components of the orientation vector are equal to zero, whereas with increasing wall distance, all directions become equally probable. In the third part, the models are assessed in the framework of large-eddy simulation with stochastic subgrid acceleration model (LES–SSAM), introduced recently by Sabel’nikov, Chtab-Desportes & Gorokhovski (Euro. Phys. J. B, vol. 80, 2011, p. 177–187), and designed to account for the intermittency at subgrid scales. Computations by LES–SSAM and its assessment using DNS data show that the prediction of important statistics to characterize the flow, such as the mean velocity, the energy spectra at small scales, the viscous and turbulent stresses, the distribution of the acceleration can be considerably improved in comparison with standard LES. In the last part of this paper, the advantage of LES–SSAM in accounting for the subgrid flow structure is demonstrated in simulation of particle-laden turbulent channel flows. Compared to standard LES, it is shown that for different Stokes numbers, the particle dynamics and the turbophoresis effect can be predicted significantly better when LES–SSAM is applied.

scholarly journals A New Technique in Management of Pilonidal Sinus, a University Teaching Hospital Experience

2013 ◽  
Vol 98 (4) ◽  
pp. 304-306 ◽  
Author(s):  
Saleh M. Aldaqal ◽  
Ahmed A. Kensarah ◽  
Mostafa Alhabboubi ◽  
Abdulrahman A. Ashy
Keyword(s):  
Recurrence Rate ◽  
Pilonidal Sinus ◽  
Primary Closure ◽  
Healing Time ◽  
New Technique ◽  
Controlled Study ◽  
P Value ◽  
Minimal Amount ◽  
The Mean ◽  
A New Technique

Abstract This paper evaluates a new technique that can lead to excision of pilonidal sinus with less healing time and low recurrence rate. A prospective randomized double-blind controlled study on 142 patients with pilonidal sinus conducted during the period from September 2008 to March 2012. The patients were prospectively randomized to be operated with one of four surgical techniques, excision and primary closure, or excision after using hydrogen peroxide (H202) and primary closure, or excision without closure, or excision after injection of H202 without closure. The main outcome measures were the healing time and the recurrence rate. Out of 142 patients, 118 patients were males (83%), and 24 were females (17%). The mean age was 24.5 years. The recurrence rate in patients treated with excision after injection of H202 without closure was the lowest (1.8%) with P-value < 0.005, and the mean duration of healing was 30.7 days with P-value < 0.005. We recommend using excision after injection of H202 without closure in management of PNS. Injection of H202 into the pilonidal tracts can give a precise delineation of the affected tracts, which can be excised with minimal amount of surrounding normal tissues and hence lead to a quicker recovery and low recurrence rate.

New Technique for Quantitative SiO2 Determinations of Silicate Materials by X-Ray Diffraction Analysis of Glass

1963 ◽  
Vol 7 ◽  
pp. 209-228 ◽  
Author(s):  
Douglas B. Nash
Keyword(s):  
Diffraction Analysis ◽  
Silicate Glasses ◽  
New Technique ◽  
Inverse Relation ◽  
Diffraction Maximum ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Mean ◽  
A New Technique ◽  
Silicate Materials

AbstractResults of an experimental X-ray study on 96 synthetic glasses show that the 2θ positions of glass diffraction maxima have an inverse relation to SiO2 concentration in silicate glasses. This relationship is the basis of a new technique for semiquantitative determinations of SiOa in silicate materials by X-ray diffraction methods. Samples to be examined are fused and the resulting glass scanned from 12 to 40° 2θ using CiiKa radiation. The mean 2θ position of the diffraction maximum is a measure of the SiOs content of the glass. Calibration curves for both weight and molecular percent SiO2 vs. 2θ are presented in this report. The technique requires only small, unweighed amounts of sample for analysis ; it is simple, rapid, and utilizes standard diffraction equipment without modification. Its accuracy, at present, allows SiOa determinations to within ±1 to 4% of the actual concentration.

scholarly journals Improved strategy for computation of population mean under double stratified sampling framework

2021 ◽  
Vol 17 (2) ◽  
pp. 91-102
Author(s):  
S. M. Zeeshan ◽  
G. K. Vishwakarma
Keyword(s):  
Finite Population ◽  
New Technique ◽  
Second Phase ◽  
Estimation Technique ◽  
Ratio Estimation ◽  
Initial Sample ◽  
Population Mean ◽  
The Mean ◽  
Phase Sample ◽  
A New Technique

Abstract The article contains a new technique to estimate the mean of the variate of the interest of the finite population with the help of two auxiliary variates. The technique complies well with the stratified population in which each strata proportion is predicted by taking an initial sample called the first phase sample. When the first phase sample is taken, a second sample is taken from the first sample which is called the second phase sample which is used to estimate the mean of the variate of the interest. In our study, we have considered the population which has two correlated auxiliary variates that pass almost through the origin. In such a situation ratio estimation technique and product estimation technique that provides improved estimates of the mean of the variate of the interest. Our technique considers a ratio-product type exponential estimator of which we have established efficiency theoretically as well as empirically.

Correction to ‘Free convection effect on the oscillatory flow past an infinite, vertical, porous plate with constant suction. I’ (Soundalgekar, V. M. 1973)

1977 ◽  
Vol 353 (1673) ◽  
pp. 221-223 ◽  
Keyword(s):  
Free Convection ◽  
Skin Friction ◽  
Mathematical Reasoning ◽  
Frictional Heating ◽  
Porous Plate ◽  
Fluid Temperature ◽  
Mean Velocity ◽  
Plate Temperature ◽  
Mean Temperature ◽  
The Mean

In the paper noted in the title we have found a few mistakes and wish to correct them in this note. First we infer from the non-dimensional temperature θ (= ( T ' - T ' ∞ ) / ( T ' w - T ' ∞ )) and the Grashof number G (= ( T ' w - T ' ∞ ) / ∆ T with ∆ T = U 0 v 2 0 / vg x β ) that T ' ∞ only is kept constant and as G varies so does T ' w . For example, as G , being positive, takes increasing values T ' w increases and hence the fluid subsequently gets heated up as a result of heat-balance. Consequently we expect the fluid temperatures θ 0 (say, for a fixed Y ) to increase with positive G and to decrease with negative G and these results are not in evidence from figures 5-7 of Soundalgekar (1973), which are incorrect. That the results incorporated in and depicted by figures 5-7 cannot be all correct may be understood by a simple mathematical reasoning, namely: if E > 0, θ 0 cannot have a minimum as shown in figure 5 because from equation (20) of the reference, θ H 0 < 0 when θ ' 0 = 0 and if E < 0, θ 0 cannot have a maximum as shown in figure 7. Further it is necessary to know the quantitative nature of the errors committed in the paper. Therefore we have reworked out the problem and evaluated on I. B. M. 1620 the numerical values of the dimensionless mean velocity u 0 , the mean skin friction τ and the mean temperature θ 0 . We have found that the mean velocity diagrams, the values of the mean skin friction and the expression (37) for θ 0 are all correct. But the mean temperature profiles as shown in figures 5-7 are all incorrect! The correct values of the dimensionless mean temperature θ 0 have been presented in this note through figures 1-3. It is quite clear that θ 0 , as expected, increases with positive G significantly in the case of air ( P = 0.71). Physically it means that as the plate temperature T ' w increases (positive G increases) the fluid-temperature increases. This behaviour of θ 0 gets duly reversed when G , being negative, takes increasing values (see figure 3, P = 0.71). In the presence of free convection parameter G the mean temperature θ 0 increases as the frictional heating (positive E ) increases, a result in contrast to that reported by Soundalgekar. Moreover when the Prandtl number P is large, the effect of G (positive or negative) on θ 0 is almost insignificant - a result contrary to the one obtained by Soundalgekar.

A NEW BIOASSAY TECHNIQUE FOR THE MEASUREMENT IN VITRO OF THYROTROPHIC HORMONE IN SERUM AND IN PITUITARY EXTRACTS

1962 ◽  
Vol 25 (2) ◽  
pp. 259-269 ◽  
Author(s):  
K. E. KIRKHAM
Keyword(s):  
Thyroid Tissue ◽  
Mean Value ◽  
Assay Method ◽  
Human Pituitary ◽  
Thyrotrophic Hormone ◽  
Bioassay Technique ◽  
The Mean ◽  
A New Technique ◽  
New Bioassay

SUMMARY A new technique by which thyrotrophic hormone (TSH) can be rapidly measured in vitro in the serum of euthyroid subjects and in human pituitary extracts is presented. In euthyroid male subjects levels of TSH in serum ranged from 0 to 30·1 i.u. × 10−3/100ml., the mean value being 10·8. In normal menstruating women the mean value was 4·8 and the range 0 to 21·5 i.u. × 10−3/100 ml. In human pituitary extracts, TSH could be detected in all fractions tested, but the amount of activity present was greatest in the gonadotrophin fraction. When the latter was separated into the FSH and LH components the TSH activity was found to be mainly associated with the LH fraction. The specificity of the method has been examined by incubating thyroid tissue with other hormones of pituitary origin and measuring their effect on the response to TSH. It is concluded that any interference with the assay method produced by FSH and LH is due to their contamination with TSH.

A SURVEY OF RAMANUJAN EXPANSIONS

2010 ◽  
Vol 06 (08) ◽  
pp. 1785-1799 ◽  
Author(s):  
LUTZ G. LUCHT
Keyword(s):  
Mean Value ◽  
Arithmetic Functions ◽  
New Technique ◽  
Multiplicative Functions ◽  
A New Technique ◽  
Ramanujan Expansions

This paper summarizes the development of Ramanujan expansions of arithmetic functions since Ramanujan's paper in 1918, following Carmichael's mean-value-based concept from 1932 up to 1994. A new technique, based on the concept of related arithmetic functions, is introduced that leads to considerable extensions of preceding results on Ramanujan expansions. In particular, very short proofs of theorems for additive and multiplicative functions going far beyond previous borders are presented, and Ramanujan expansions that formerly have been considered mysterious are explained.

scholarly journals A new technique for studying the Fano factor and the mean energy per ion pair in counting gases

1996 ◽  
Vol 79 (12) ◽  
pp. 8892-8898 ◽  
Author(s):  
A. Pansky ◽  
A. Breskin ◽  
R. Chechik
Keyword(s):  
Fano Factor ◽  
Ion Pair ◽  
New Technique ◽  
The Mean ◽  
A New Technique
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