scholarly journals Experimental Study of Aircraft Achieving Dutch Roll Mode Stability without Weathercock Stability

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jingcheng Fu ◽  
Jun Huang ◽  
Lei Song ◽  
Daqing Yang
Keyword(s):  
Experimental Study ◽  
Numerical Analysis ◽  
Quality Analysis ◽  
Flight Experiment ◽  
Handling Characteristics ◽  
Marginal Change ◽  
Mode Stability ◽  
Mode Characteristics ◽  
The Difference ◽  
Dutch Roll

Weathercock stability is usually considered essential to achieve normal flight, while the Dutch roll mode stability can still be achieved without weathercock stability which has been algebraically proved. This paper proposed a flight experiment to investigate the characteristics of an airplane with Dutch roll mode stability but no weathercock stability. Firstly, the algebraic analysis based on a standard lateral-directional mode approximation was made to demonstrate the effect of yawing stability derivative Cnβ on the Dutch roll mode characteristics. The flight experiment was organized after that using a model glider which was modified to have zero Cnβ but with marginal change on Cyβ. The convergence of Dutch roll mode in flight meets the algebraic and numerical analysis as expected. However, the difference of handling characteristics between the original and modified configurations indicates some other roles the weathercock stability plays in flight as well as some limitations of utilizing mode criterion in flight quality analysis.

Dose-window dependence on Si crystal orientation in separation by implanted oxygen substrate formation

2004 ◽  
Vol 19 (12) ◽  
pp. 3607-3613 ◽  
Author(s):  
H. Iikawa ◽  
M. Nakao ◽  
K. Izumi
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Crystal Orientation ◽  
Oxygen Ion ◽  
The Difference ◽  
First Time ◽  
Good Agreement

Separation by implemented oxygen (SIMOX)(111) substrates have been formed by oxygen-ion (16O+) implantation into Si(111), showing that a so-called “dose-window” at 16O+-implantation into Si differs from Si(100) to Si(111). In SIMOX(100), an oxygen dose of 4 × 1017/cm2 into Si(100) is widely recognized as the dose-window when the acceleration energy is 180 keV. For the first time, our work shows that an oxygen dose of 5 × 1017/cm2 into Si(111) is the dose-window for the formation of SIMOX(111) substrates when the acceleration energy is 180 keV. The difference between dose-windows is caused by anisotropy of the crystal orientation during growth of the faceted buried SiO2. We also numerically analyzed the data at different oxidation velocities for each facet of the polyhedral SiO2 islands. Numerical analysis results show good agreement with the experimental data.

Experimental Study of Bending Toughness on Hybrid Fiber Reinforced Concrete

2013 ◽  
Vol 327 ◽  
pp. 201-204
Author(s):  
Jin Song Shi ◽  
Bo Yuan ◽  
Da Zhang Wang ◽  
Zhe An Lu
Keyword(s):  
Experimental Study ◽  
Reinforced Concrete ◽  
Fiber Reinforced Concrete ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Toughness Index ◽  
The Difference ◽  
Loading Methods ◽  
Index Value

In order to investigate the difference of current toughness index standards for fiber reinforced concrete, two main groups of specimens were made to take bending toughness test with the requirements of corresponded standards, loading methods and loading speeds, which are ASTM C1018 in America, ACI 544 and JSCE G552 in Japan. United with software Origin, the load-deflection curves gathered from bending test was calculated with relative standards. The results show that the calculated toughness index value with ASTM C1018-98 in America is more accurate with three grades but the requested deflection of testing is much longer than others while ACI 544 and JSCE G552 in Japan are quite the contrary.

The Quality Analysis of Hallux Valgus Videos on YouTube

2021 ◽  
Author(s):  
Enes Sari ◽  
Levent FAZLI Umur
Keyword(s):  
Hallux Valgus ◽  
Information Quality ◽  
Statistical Significance ◽  
Poor Quality ◽  
Quality Analysis ◽  
Accurate Information ◽  
Youtube Videos ◽  
The Mean ◽  
The Difference

BACKGROUND:The aim of this study was to evaluate the information quality of YouTube videos on hallux valgus. METHODS:A YouTube search was performed using the keyword 'hallux valgus' to determine the first 300 videos related to hallux valgus. A total of 54 videos met our inclusion criteria and evaluated for information quality by using DISCERN, Journal of the American Medical Association (JAMA) and hallux valgus information assessment (HAVIA) scores. Number of views, time since the upload date, view rate, number of comments, number of likes, number of dislikes, video power index (VPI) values were calculated to determine video popularity. Video length (sec), video source and video content were also noted. The relation between information quality and these factors were statistically evaluated. RESULTS:The mean DISCERN score was 30.35{plus minus}11.56 (poor quality) (14-64), the mean JAMA score was 2.28{plus minus}0.96 (1-4), and the mean HAVIA score was 3.63{plus minus}2.42 (moderate quality) (0.5-8.5). Although videos uploaded by physicians had higher mean DISCERN, JAMA, and HAVIA scores than videos uploaded by non-physicians, the difference was not statistically significant. Additionally, view rates and VPI values were higher for videos uploaded by health channels, but the difference did not reach statistical significance. A statistically significant positive correlation was found between video length and DISCERN (r= 0.294, p= 0.028), and HAVIA scores (r= 0.326, p= 0.015). CONCLUSIONS:This present study demonstrated that the quality of information available on YouTube videos about hallux valgus was low and insufficient. Videos containing accurate information from reliable sources are needed to educate patients on hallux valgus, especially in less frequently mentioned topics such as postoperative complications and healing period.

Analysis on Kinematic Characteristics of Precision Balls Grinding

2012 ◽  
Vol 497 ◽  
pp. 20-24
Author(s):  
Yong Dai ◽  
Dong Hui Ding ◽  
Xu Xiao ◽  
Xue Shi Liu ◽  
Rui Jiang He ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Great Influence ◽  
Processing Parameters ◽  
Important Influence ◽  
Normal Movement ◽  
Motion State ◽  
Kinematic Characteristics ◽  
The Difference

In the process of grinding precision balls, the motion state of balls has an important influence on the efficiency and quality. However, the normal movement of balls will be damaged because of slipping, so it must be avoided. Besides, to process different materials of balls, it should use different processing parameters. This paper studies a numerical analysis on the kinematic characteristics of the motion of balls, analyzes processing parameters which impact the motion of balls during grinding and the difference of the motion state of bearing balls and resin balls. Study shows grinding pressure and plate speed have a great influence to the motion of balls during grinding.

NUMERICAL REEXAMINATION OF SUPERSYMMETRIC AND NONSUPERSYMMETRIC SU(5)-LIKE GRAND UNIFIED MODELS

1989 ◽  
Vol 04 (10) ◽  
pp. 2531-2559 ◽  
Author(s):  
DARIUSZ K. GRECH
Keyword(s):  
Numerical Analysis ◽  
Numerical Computation ◽  
Numerical Results ◽  
Yukawa Couplings ◽  
Loop Level ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Supersymmetric Particles ◽  
The Difference

The significance of numerical analysis in both nonsupersymmetric and supersymmetric Grand Unified Theories is pointed out. The exact analytical and numerical analysis we present shows a need of larger corrections to the values of unifying parameters, i.e. sin 2 θw, Mx, τp than those often quoted in literature. When an unmodified nonsupersymmetric version of SU(5) is considered we show that numerical computation allows some of the models still to be experimentally admissible. The difference between analytical and numerical results for the supersymmetric SU(5) model is also stressed. In particular, corrections due to the mass threshold of additional generations or supersymmetric particles are calculated both analytically and numerically at the two-loop level. We found them far more important for the final values of sin 2 θw, Mx and τp than the effects of Higgs-Yukawa couplings between scalars and fermions.

scholarly journals Strength Comparison of FDM 3D Printed PLA Made by Different Manufacturers

TEM Journal ◽  
2020 ◽  
pp. 966-970
Author(s):  
Damir Hodžić ◽  
Adi Pandžić ◽  
Ismar Hajro ◽  
Petar Tasić
Keyword(s):  
Experimental Study ◽  
Additive Manufacturing ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Manufacturing Technique ◽  
Plastic Materials ◽  
Wide Range ◽  
3D Printed ◽  
The Difference ◽  
Printing Parameters

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.

scholarly journals Perbedaan Indeks Plak setelah Pengolesan Ekstrak Daging Buah Naga Merah (Hylocereus costaricensis) dan Larutan Pengungkap

2019 ◽  
Vol 16 (1) ◽  
pp. 21
Author(s):  
Hillary Inggrid Prananta ◽  
Purwanto Purwanto ◽  
Elyda Akhya Afida Misrohmasari ◽  
Niken Probosari ◽  
Surartono Dwiatmoko
Keyword(s):  
Experimental Study ◽  
Hydrogen Bonds ◽  
Dental Plaque ◽  
Plaque Index ◽  
Group Comparison ◽  
Fruit Flesh ◽  
Dragon Fruit ◽  
Significant Difference ◽  
The Difference ◽  
Static Group

Red dragon fruit flesh extract contains of anthocyanin as red pigmen that potentially to be a natural dye. Athocyanin contains of polysaccharide that can binding with polysaccharide of dental plaque called hydrogen bonds, so dental plaque has been colored and potentially as alternative of disclosing solution. The purpose of this study was to find out the difference of plaque index after smeared by red dragon fruit flesh extract 75% and disclosing solution. The method of this study is a clinical experimental study with a static-group comparison design. 20 subjects were examined the plaque index after smeared with red dragon fruit flesh extract 75%) and disclosing solution). There was no significant difference between groups. Conclusions: Red dragon fruit flesh extract 75% had similar capability with disclosing solution to examine dental plaque.

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