scholarly journals A Model Analysis of Tensile Stress in the Toadfish Vestibular Membranes

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Daniel J. Pender
Keyword(s):  
Theoretical Model ◽  
Tensile Stress ◽  
Semicircular Canal ◽  
Hoop Stress ◽  
Peak Stress ◽  
Model Analysis ◽  
Stress Factor ◽  
Vestibular Labyrinth ◽  
The Mean

Background. A theoretical model analysis of stress in the vestibular membranes has identified a geometrical stress factor incorporating shape, size, and thickness that can be used to assess peak stress in the various chambers.Methods. Using published measurements of the toadfish vestibular membranes made during surgery, the geometrical stress factor can be evaluated for each chamber based on the model.Results. The mean geometrical stress factor is calculated to be the lowest in the semicircular canal (4.4), intermediate in the ampulla (6.0), and the highest in the utricle (17.4).Conclusions. The model predicts that substantial hoop stress disparities exist in the toadfish vestibular labyrinth. Stress is least in the semicircular canal, which therefore appears to be the structure with greatest stability. The utricle is found to be the most stress prone structure in the vestibular labyrinth and therefore appears to be the chamber most vulnerable to distention and potential modification.

HRA Model for Hypercholesterolemia Based on a Longitudinal Health Database

1998 ◽  
Vol 37 (02) ◽  
pp. 130-133
Author(s):  
T. Kishimoto ◽  
Y. Iida ◽  
K. Yoshida ◽  
M. Miyakawa ◽  
H. Sugimori ◽  
...  
Keyword(s):  
Total Cholesterol ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Model Analysis ◽  
Serum Total Cholesterol ◽  
Hazards Model ◽  
The Mean ◽  
Health Database ◽  
Observation Period

AbstractTo evaluate the risk factors for hypercholesterolemia, we examined 4,371 subjects (3,207 males and 1,164 females) who received medical checkups more than twice at an AMHTS in Tokyo during the period from 1976 through 1991; and whose serum total cholesterol was under 250 mg/dl. The mean follow-up duration was 6.6 years. A self-registering questionnaire was administered at the time of the health checkup. The endpoint of this study was the onset of hypercholesterolemia when the level of serum total cholesterol was 250 mg/dl and over. We compared two prognosis groups (normal and hypercholesterol) in terms of age, examination findings and lifestyle. After assessing each variable, we employed Cox's proportional hazards model analysis to determine the factors related to the occurrence of hypercholesterolemia. According to proportional hazards model analysis, total cholesterol, triglyceride and smoking at the beginning, and hypertension during the observation period were selected in males; and total cholesterol at the beginning and age were selected in females to determine the factors related to the occurrence of hypercholesterolemia.

scholarly journals Formulation and in vitro evaluation of self-nanoemulsifying liquisolid tablets of furosemide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Dalal ◽  
Abdul Wahab Allaf ◽  
Hind El-Zein
Keyword(s):  
Theoretical Model ◽  
Castor Oil ◽  
In Vivo Studies ◽  
Coating Materials ◽  
Peg 400 ◽  
The Mean ◽  
Usp Apparatus ◽  
Solid System

AbstractSelf-nanoemulsifying drug delivery systems (SNEDDS) were used to enhance the dissolution rate of furosemide as a model for class IV drugs and the system was solidified into liquisolid tablets. SNEDDS of furosemide contained 10% Castor oil, 60% Cremophor EL, and 30% PEG 400. The mean droplets size was 17.9 ± 4.5 nm. The theoretical model was used to calculate the amounts of the carrier (Avicel PH101) and coating materials (Aerosil 200) to prepare liquisolid powder. Carrier/coating materials ratio of 5/1 was used and Ludipress was added to the solid system, thus tablets with hardness of 45 ± 2 N were obtained. Liquisolid tablets showed 2-folds increase in drug release as compared to the generic tablets after 60 min in HCl 0.1 N using USP apparatus-II. Furosemide loaded SNEDDS tablets have great prospects for further in vivo studies, and the theoretical model is useful for calculating the adequate amounts of adsorbents required to solidify these systems.

Development and Application of a Concept Test on the Subject of Stars

2020 ◽  
Author(s):  
Ebru EZBERCI-CEVIK ◽  
Mehmet Altan KURNAZ
Keyword(s):  
Quantitative Research ◽  
Quantitative Methods ◽  
Model Analysis ◽  
Validity And Reliability ◽  
Multiple Choice Questions ◽  
Schools Of Education ◽  
Test Items ◽  
Alpha Reliability ◽  
The Subject ◽  
The Mean

The aim of this study is to develop a concept test on the subject of stars that is suitable for model analysis and to evaluate the conformity of this model. The study was performed using a screening model, which is a type of quantitative research method. The study also tried to fill the gap in the existing literature regarding the use of quantitative methods. To develop the test, existing studies on stars were first examined; interviews with candidates who were teachers were conducted; and finally, necessary amendments to test items were made after referring to experts’ opinions. To assure its validity and reliability, the test was applied to a total of 175 candidates who were studying at schools of education in the departments of science teaching of three different universities to become teachers; all candidates took astronomy courses and were educated on the subject matter. The final form of the test comprised of 26 multiple-choice questions, each with 5 possible answers. The Cronbach’s alpha reliability coefficient of the test was calculated to be 0.735. In addition, the mean strength of the test was found to be 0.370 and the distinctiveness was found to be 0.390. Statistical analyses revealed that the concept test developed in this study is a valid and reliable test that conforms to the model analysis.

scholarly journals A comparison between orthodontic model analysis using conventional methods and iModelAnalysis

2018 ◽  
Vol 51 (4) ◽  
pp. 173
Author(s):  
Vita Previa Indirayana ◽  
Gita Gayatri ◽  
N. R. Yuliawati Zenab
Keyword(s):  
Sampling Method ◽  
Model Analysis ◽  
T Test ◽  
Normality Test ◽  
Time Period ◽  
Significant Difference ◽  
The Mean ◽  
Conventional Methods ◽  
Paired T Test ◽  
Dental Casts

Background: Model analysis constitutes an essential aspect of orthodontic diagnostic practice. Pavan has developed an application to simplify the mathematical calculations employed in orthodontic model analysis. Purpose: This study was conducted to obtain the differences in results and time periods of model analysis using conventional means and iModelAnalysis. Methods: The research represented a comparative analytic study. The populations comprised dental casts dating from 2014 in the Orthodontics Laboratory of Padjadjaran University. The samples comprised 31 dental casts which were subjected to a total sampling method consisting of two treatments; a conventional method calculation and one using iModelAnalysis. A normality test was conducted and processed using a paired t-test with α=0.05. Results: The means of arch length discrepancies were 1.64±2.63 mm and 1.37±3.07 mm for the conventional methods and 1.65±2.43mm and 1.42±3.04mm for iModelAnalysis. The results of a Bolton analysis for conventional methods were 78.05±2.69% and 91.93±1.29%, while those for iModelAnalysis were 77.91±2.70% and 91.96±2.13%. A Howes analysis of conventional methods produced a result of 45.56±2.83%, while for an iModelAnalysis one of 45.56±2.85%. Pont analysis for conventional methods was 39.35±0.04 mm and 49.17±2.55 mm, while for iModelAnalysis it was 39.35±0.07 mm and 49.19±2.57mm. The mean of the duration of analysis using conventional methods was 1703.81±56.46 seconds, while for iModelAnalysis it was 990.06±34.87 seconds. A normality test confirmed that the data was normally distributed (p>0.05). The results of a paired sample t-test with p>0.05 showed that there was no significant difference between the results of each analysis, while there was significant difference in the time period of analysis. Conclusion: There was no difference in the analysis results. However, there was difference in the time period of analysis between conventional methods and that of iModelAnalysis.

Computational Analysis of Displacement of Particles with Given Size on the Nonstationary Bulging Membrane as a Theoretical Model of Membrane Fouling

2013 ◽  
Vol 34 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Jakub M. Gac ◽  
Leon Gradoń
Keyword(s):  
Particle Size ◽  
Theoretical Model ◽  
Membrane Fouling ◽  
Computational Analysis ◽  
New Production ◽  
Mean Velocity ◽  
Production Methods ◽  
The Mean ◽  
Particle Behaviour ◽  
Diffusive Behaviour

Abstract A simple model of behaviour of a single particle on the bulging membrane was presented. As a result of numerical solution of a motion equation the influence of the amplitude and frequency of bulging as well as the particle size on particle behaviour, especially its downstream velocity was investigated. It was found that the bulging of a membrane may increase the mean velocity of a particle or reinforce its diffusive behaviour, dependeing on the permeation velocity. The obtained results may help to design new production methods of highly fouling-resistant membranes.

scholarly journals Dispersive optical model analysis of Pb208 generating a neutron-skin prediction beyond the mean field

2020 ◽  
Vol 101 (4) ◽  
Author(s):  
M. C. Atkinson ◽  
M. H. Mahzoon ◽  
M. A. Keim ◽  
B. A. Bordelon ◽  
C. D. Pruitt ◽  
...  
Keyword(s):  
Optical Model ◽  
Mean Field ◽  
Model Analysis ◽  
Neutron Skin ◽  
The Mean ◽  
Optical Model Analysis

scholarly journals Investigation on the Curvature Correction Factor of Extension Spring

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4199
Author(s):  
P. S. Tan ◽  
Ali Akhavan Farid ◽  
Atefeh Karimzadeh ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů
Keyword(s):  
Finite Element ◽  
Theoretical Model ◽  
Numerical Methods ◽  
Tensile Stress ◽  
Correction Factor ◽  
Fe Model ◽  
Stress Increase ◽  
Curvature Correction ◽  
Spring Wire ◽  
Inner Radius

The curvature correction factor is an important parameter in the stress calculation formulation of a helical extension spring, which describes the effect of spring wire curvature on the stress increase towards its inner radius. In this study, the parameters affecting the curvature correction factor were investigated through theoretical and numerical methods. Several finite element (FE) models of an extension spring were generated to obtain the distribution of the tensile stress in the spring. In this investigation, the hook orientation and the number of coils of the extension spring showed significant effects on the curvature correction factor. These parameters were not considered in the theoretical model for the calculation of the curvature correction factor, causing a deviation between the results of the FE model and the theoretical approach. A set of equations is proposed for the curvature correction factor, which relates both the spring index and the number of coils. These equations can be applied directly to the design of extension springs with a higher safety factor.

scholarly journals Experimental Evaluation of Squeeze Film Supported Flexible Rotors

1982 ◽  
Author(s):  
M. D. Rabinowitz ◽  
E. J. Hahn
Keyword(s):  
Theoretical Model ◽  
Experimental Evaluation ◽  
Measurement Errors ◽  
Vibration Amplitude ◽  
Squeeze Film ◽  
Experimental Investigations ◽  
Flexible Rotors ◽  
The Mean ◽  
Lubricant Viscosity ◽  
Theory And Experiment

This paper describes the experimental investigations which were conducted to verify existing theoretical vibration amplitude predictions for centrally preloaded, squeeze film supported flexible rotors. The influence of measurement errors and operating condition uncertainties are quantified. The agreement between theory and experiment was excellent, and it is shown that any discrepancy can be explained in terms of errors in determining the mean lubricant viscosity and the orbit magnitudes. Hence, for the range of parameters investigated, the theoretical model and predictions therefrom are validated.

Research on Dynamic Design Method Based on Measuring Information for Printing Press

2010 ◽  
Vol 174 ◽  
pp. 290-294
Author(s):  
Yi Ming Wang ◽  
Bang She Chen ◽  
Yan Li ◽  
Shao Hua Zhang
Keyword(s):  
Theoretical Model ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Design Method ◽  
Model Analysis ◽  
Printing Press ◽  
Vibration Measurement ◽  
Dynamic Design ◽  
Analysis Experiment ◽  
Printing Machine

Printing machinery’s reliability is one of the most important index parameter and good dynamic characteristics are essential for high speed printing press. The dynamic characteristic is predictable for printing machine with dynamic design. With the complexity of printing technique and printing machine, information, such as load on components is lack, leading to the difficulty of dynamic model solving and further more the dynamic parameters needs to be verified. Firstly, according to the dynamic design method, a dynamic design process based on measuring information for printing machine was put forward. Secondly, on the basis of principle and structure analysis to typical printing machine, dynamic characteristics measurement item and method was determined. With a wallboard of a two-color offset press acting as an example, the utilizing method was illustrated through dynamic modeling, theoretical model analysis, experiment model analysis based on vibration measurement and comparing the theoretical and experimental results. Finally, a Dynamic Design Assistant Platform based Vibration Measurement for Printing Machine was developed and had been used in 10 kinds of printing machine measurement and analysis. The conclusion shows that the tolerance of the theoretical model analysis results and experiment results is allowed. A new approach for new printing machine design and optimal design for existed printing machine is given.

Sign in / Sign up

Export Citation Format

Share Document