scholarly journals DEPENDENCE OF THE MEAN AND DISPERSION OF GRAIN WIDTH OF SILICON CARBIDE BLACK GRINDING POWDERS ON THE MESH SIZE OF A PASS SIEVE

2016 ◽  
Vol 2016 (5) ◽  
pp. 8-15 ◽  
Author(s):  
Владимир Носенко ◽  
Vladimir Nosenko ◽  
Алексей Александров ◽  
Aleksey Aleksandrov
Keyword(s):  
Silicon Carbide ◽  
Mesh Size ◽  
Grit Size ◽  
Photometric Method ◽  
Distribution Law ◽  
Main Fraction ◽  
Fraction Increase ◽  
The Mean ◽  
Grain Width ◽  
Normal Law

Silicon carbide black grinding powders 54CF180-F36, mass-produced at Volzhsky Abrasive Plant are studied. Powders are screened into fractions according to GOST R 52381. Measurement of a grain width of each fraction was carried out by means of a photometric method using specially developed soft-ware. For the vast majority of fractions the grain width follows the normal distribution law. The deviation of the grain width from the normal law can be observed at the fractions settled on the second sieve and the pallet. With decreasing the nominal mesh size of a pass sieve in each grit size the arithmetic mean of grain width of the main fraction decreases, dispersion reduces from the fraction settling on the second sieve to the fourth and increases at the fraction settling on the pallet. In case of the identical mesh size of a pass sieve the mean and dispersion of grain width fraction increase with grinding powder grit increase. For each grit size the functional dependences of the mean and dispersion of grain width fraction on a mesh size of a pass sieve are established.

scholarly journals EVALUATION OF ECONOMIC SECURITY LEVEL OF THE MINERAL-RAW MATERIAL COMPLEX IN THE BRYANSK REGION

2016 ◽  
Vol 2016 (5) ◽  
pp. 115-120
Author(s):  
Ольга Дадыкина ◽  
Olga Dadykina
Keyword(s):  
Mesh Size ◽  
Economic Security ◽  
Grit Size ◽  
Raw Material ◽  
Security Level ◽  
Distribution Law ◽  
Fraction Increase ◽  
The Mean ◽  
Grain Width ◽  
Normal Law

Silicon carbide black grinding powders 54CF180-F36, mass-produced at Volzhsky Abrasive Plant are studied. Powders are screened into fractions according to GOST R 52381. Measurement of a grain width of each fraction was carried out by means of a photome-tric method using specially developed software. For the vast majority of fractions the grain width follows the normal distribution law. The deviation of the grain width from the normal law can be observed at the frac-tions settled on the second sieve and the pallet. With decreasing the nominal mesh size of a pass sieve in each grit size the arithmetic mean of grain width of the main fraction decreases, dispersion reduces from the fraction settling on the second sieve to the fourth and increases at the fraction settling on the pallet. In case of the identical mesh size of a pass sieve the mean and dispersion of grain width fraction increase with grinding powder grit increase. For each grit size the functional dependences of the mean and dispersion of grain width fraction on a mesh size of a pass sieve are established.

TEM of grain growth and phase transformations during creep of SCS-6 silicon carbide fibers

1995 ◽  
Vol 53 ◽  
pp. 350-351
Author(s):  
L. A. Giannuzzi ◽  
C. A. Lewinsohn ◽  
C. E. Bakis ◽  
R. E. Tressler
Keyword(s):  
Silicon Carbide ◽  
Creep Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Primary Creep ◽  
Excess Carbon ◽  
Silicon Carbide Fibers ◽  
Sic Fiber ◽  
Carbon Core ◽  
Grain Width

The SCS-6 SiC fiber is a 142 μm diameter fiber consisting of four distinct regions of βSiC. These SiC regions vary in excess carbon content ranging from 10 a/o down to 5 a/o in the SiC1 through SiC3 region. The SiC4 region is stoichiometric. The SiC sub-grains in all regions grow radially outward from the carbon core of the fiber during the chemical vapor deposition processing of these fibers. In general, the sub-grain width changes from 50nm to 250nm while maintaining an aspect ratio of ~10:1 from the SiC1 through the SiC4 regions. In addition, the SiC shows a <110> texture, i.e., the {111} planes lie ±15° along the fiber axes. Previous has shown that the SCS-6 fiber (as well as the SCS-9 and the developmental SCS-50 μm fiber) undergoes primary creep (i.e., the creep rate constantly decreases as a function of time) throughout the lifetime of the creep test.

scholarly journals Probability Characteristics, Area Reduction, and Wind Directionality Effects of Extreme Pressure Coefficients of High-Rise Buildings

2021 ◽  
Vol 11 (15) ◽  
pp. 7121
Author(s):  
Shouke Li ◽  
Feipeng Xiao ◽  
Yunfeng Zou ◽  
Shouying Li ◽  
Shucheng Yang ◽  
...  
Keyword(s):  
Probability Distribution ◽  
Pressure Coefficient ◽  
Wind Pressure ◽  
Extreme Pressure ◽  
Distribution Law ◽  
Distribution Fitting ◽  
Pressure Coefficients ◽  
High Rise ◽  
Area Reduction ◽  
The Mean

Wind tunnel tests are carried out for the Commonwealth Advisory Aeronautical Research Council (CAARC) high-rise building with a scale of 1:400 in exposure categories D. The distribution law of extreme pressure coefficients under different conditions is studied. Probability distribution fitting is performed on the measured area-averaged extreme pressure coefficients. The general extreme value (GEV) distribution is preferred for probability distribution fitting of extreme pressure coefficients. From the comparison between the area-averaged coefficients and the value from GB50009-2012, it is indicated that the wind load coefficients from GB50009-2012 may be non-conservative for the CAARC building. The area reduction effect on the extreme wind pressure is smaller than that on the mean wind pressure from the code. The recommended formula of the area reduction factor for the extreme pressure coefficient is proposed in this study. It is found that the mean and the coefficient of variation (COV) for the directionality factors are 0.85 and 0.04, respectively, when the orientation of the building is given. If the uniform distribution is given for the building’s orientation, the mean value of the directionality factors is 0.88, which is close to the directionality factor of 0.90 given in the Chinese specifications.

scholarly journals An alternative to the rejection of observations

1932 ◽  
Vol 137 (831) ◽  
pp. 78-87 ◽  
Keyword(s):  
Standard Deviation ◽  
Continuous Function ◽  
Large Deviations ◽  
Opposite Direction ◽  
Standard Error ◽  
The Other ◽  
Cause Of Error ◽  
The Mean ◽  
Normal Law ◽  
Usual Rule

1. It is widely felt that any method of rejecting observations with large deviations from the mean is open to some suspicion. Suppose that by some criterion, such as Peirce’s and Chauvenet’s, we decide to reject observations with deviations greater than 4 σ, where σ is the standard error, computed from the standard deviation by the usual rule; then we reject an observation deviating by 4·5 σ, and thereby alter the mean by about 4·5 σ/ n , where n is the number of observations, and at the same time we reduce the computed standard error. This may lead to the rejection of another observation deviating from the original mean by less than 4 σ, and if the process is repeated the mean may be shifted so much as to lead to doubt as to whether it is really sufficiently representative of the observations. In many cases, where we suspect that some abnormal cause has affected a fraction of the observations, there is a legitimate doubt as to whether it has affected a particular observation. Suppose that we have 50 observations. Then there is an even chance, according to the normal law, of a deviation exceeding 2·33 σ. But a deviation of 3 σ or more is not impossible, and if we make a mistake in rejecting it the mean of the remainder is not the most probable value. On the other hand, an observation deviating by only 2 σ may be affected by an abnormal cause of error, and then we should err in retaining it, even though no existing rule will instruct us to reject such an observation. It seems clear that the probability that a given observation has been affected by an abnormal cause of error is a continuous function of the deviation; it is never certain or impossible that it has been so affected, and a process that completely rejects certain observations, while retaining with full weight others with comparable deviations, possibly in the opposite direction, is unsatisfactory in principle.

scholarly journals Laparoscopic Ventral Hernia Repair Combined with Sleeve Gastrectomy in Morbidly Obese Patients: Early Outcomes

2019 ◽  
Vol 05 (03) ◽  
pp. e87-e91 ◽  
Author(s):  
Ahmed M.S.M. Marzouk ◽  
Heba O.E. Ali
Keyword(s):  
Sleeve Gastrectomy ◽  
Hernia Repair ◽  
Ventral Hernia ◽  
Ventral Hernia Repair ◽  
Mesh Size ◽  
Laparoscopic Ventral Hernia Repair ◽  
Abdominal Pressure ◽  
Morbidly Obese ◽  
Obese Patients ◽  
The Mean

Background Morbid obesity is a serious chronic condition with, among other symptoms, increased intra-abdominal pressure and subsequent abdominal wall hernias. The optimal management of these manifestations is still controversial. The objective of this study was to assess the early postoperative outcomes of a surgical approach combining laparoscopic ventral hernia repair (LVHR) with sleeve gastrectomy in morbidly obese patients. Methods In this retrospective study, we reviewed the files of patients who are obese with a primary ventral hernia of less than 10 cm in diameter who received simultaneous laparoscopic sleeve gastrectomy and LVHR at our institution between February 2016 and July 2018. LVHR was performed using an intraperitoneal only mesh. The individual mesh size was chosen based on the number and size of the defects. Clinical and radiological follow-ups were performed between 9 and 15 months. Results A total of 15 patients were included. Five of them were males. The mean body mass index was 45.2 kg/m2 (range: 38.7–56.2 kg/m2). The mean hernia defect size was 2.6 cm (range: 1.3–4.2 cm). Mesh size was 10 × 15 cm in five, 20 × 15 cm in seven, and 25 cm× 20 cm in three patients. All patients were discharged without complications on the second postoperative day. Mean follow-up was at 12 months. One patient presented with hernia recurrence 14 months after surgery and four patients presented with self-limited seroma. Conclusion Despite ambiguous guidelines and ongoing debate regarding simultaneous bariatric surgery and ventral hernia repair, the short-term outcomes of this approach appeared promising, provided that patients are carefully selected and receive an individually tailored approach.

On Gauss's proof of the normal law of errors

1933 ◽  
Vol 29 (2) ◽  
pp. 231-234 ◽  
Author(s):  
Harold Jeffreys
Keyword(s):  
Arithmetic Mean ◽  
Practical Case ◽  
Apparent Discrepancy ◽  
True Value ◽  
The Mean ◽  
Normal Law

Gauss gave a well-known proof that under certain conditions the postulate that the arithmetic mean of a number of measures is the most probable estimate of the true value, given the observations, implies the normal law of error. I found recently that in an important practical case the mean is the most probable value, although the normal law does not hold. I suggested an explanation of the apparent discrepancy, but it does not seem to be the true one in the case under consideration.

The Mean Projected Range and Range Straggling of Nd Ions Implanted in Silicon Carbide

2011 ◽  
Vol 474-476 ◽  
pp. 565-569
Author(s):  
Xi Feng Qin ◽  
Shuang Li ◽  
Feng Xiang Wang ◽  
Yi Liang
Keyword(s):  
Silicon Carbide ◽  
Monte Carlo ◽  
Spectrum Analysis ◽  
Monte Carlo Code ◽  
Experiment Data ◽  
Lateral Deviation ◽  
Projected Range ◽  
The Mean ◽  
The Difference ◽  
Good Agreement

In view of the influence of the projected range, the range straggling, and the lateral deviation of ions in materials on the property of device in the fabrication of photoelectric integration devices by ion implantation, the mean projected ranges and range straggling for energetic 200 – 500 keV Nd ions implanted in 6H-SiC were measured by means of Rutherford backscattering followed by spectrum analysis. The measured values are compared with Monte Carlo code (SRIM2006) calculations. It has been found that the measured values of the mean projected range Rp are good agreement with the SRIM calculated values; for the range straggling △Rp, the difference between the experiment data and the calculated results is much higher than that of Rp

Taylor’s power law and fixed-precision sampling: application to abundance of fish sampled by gillnets in an African lake

2017 ◽  
Vol 74 (1) ◽  
pp. 87-100 ◽  
Author(s):  
Meng Xu ◽  
Jeppe Kolding ◽  
Joel E. Cohen
Keyword(s):  
Power Law ◽  
Fish Assemblage ◽  
Mesh Size ◽  
Stock Management ◽  
Taylor’S Power Law ◽  
Scaling Relationship ◽  
Temporal Variance ◽  
Taylor's Power Law ◽  
Power Law Function ◽  
The Mean

Taylor’s power law (TPL) describes the variance of population abundance as a power-law function of the mean abundance for a single or a group of species. Using consistently sampled long-term (1958–2001) multimesh capture data of Lake Kariba in Africa, we showed that TPL robustly described the relationship between the temporal mean and the temporal variance of the captured fish assemblage abundance (regardless of species), separately when abundance was measured by numbers of individuals and by aggregate weight. The strong correlation between the mean of abundance and the variance of abundance was not altered after adding other abiotic or biotic variables into the TPL model. We analytically connected the parameters of TPL when abundance was measured separately by the aggregate weight and by the aggregate number, using a weight–number scaling relationship. We utilized TPL to find the number of samples required for fixed-precision sampling and compared the number of samples when sampling was performed with a single gillnet mesh size and with multiple mesh sizes. These results facilitate optimizing the sampling design to estimate fish assemblage abundance with specified precision, as needed in stock management and conservation.

Anomalous Diffusion in Active Intracellular Transport

2000 ◽  
Vol 651 ◽  
Author(s):  
Avi Caspi ◽  
Rony Granek ◽  
Michael Elbaum
Keyword(s):  
Intracellular Transport ◽  
Optical Trap ◽  
Polymer System ◽  
Mean Square Displacement ◽  
Mesh Size ◽  
Local Environment ◽  
Mode Analysis ◽  
Einstein Relation ◽  
Mean Square ◽  
The Mean

AbstractThe dynamic movements of tracer particles have been used to characterize their local environment in dilute networks of microtubules, and within living cells. In the former case, 300 nm diameter beads are fixed to individual microtubules, so that the movements of the bead reveal undulatory modes of the polymer. The mean square displacement shows a scaling of t3/4 in keeping with mode analysis arguments. Inside a cell, beads show a more complicated behavior that reflects internal dynamics of the cytoskeleton and associated motors.When placed near the cell edge, 3 micron diameter beads coated by proteins that mediate membrane adhesion are engulfed underneath the membrane and drawn toward the center by a contracting flow of actin. On reaching the region surrounding the nucleus, the beads continue to move but lose directionality, so that they wander within a restricted space. Measurement of the mean square displacement now shows a scaling of t1 up to times of ~1 sec. At longer times the scaling varies between t and t1/2 in the various runs. The data do not fit a crossover between ballistic (t2)and diffusive (t1) behavior. The movement is clearly driven by non-thermal interactions, as it cannot be stopped by an optical trap. Treatment of the cell to depolymerize microtubules restores ordinary diffusion, while actin depolymerization has no effect, indicating that microtubule-based motor proteins are responsible for the motion. Immunofluorescence microscopy shows that the mesh size of the microtubules is smaller than the bead diameter.We propose that the observations are related, and that the non-trivial scaling in the polymer system leads to time-dependent friction in a network, which in turn leads to a generalized Einstein relation operative in the intracellular environment. This results, in the driven system, in sub-ballistic motion at short times and sub-diffusive motion at longer times.

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