An Approximate Equation for Predicting the Isothermal and Nonisothermal Starved Rolling Traction in an E.H.L. Line Contact

1978 ◽  
Vol 100 (4) ◽  
pp. 472-478 ◽  
Author(s):  
P. G. Goksem ◽  
R. A. Hargreaves
Keyword(s):  
Regression Analysis ◽  
Thermal Loading ◽  
Linear Regression Analysis ◽  
Approximate Equation ◽  
Line Contact ◽  
Wide Range ◽  
Isothermal Case ◽  
Distance Parameter ◽  
Good Agreement ◽  
Distance Variable

In this paper a new inlet distance variable for the starved rolling traction is introduced. By applying a statistical linear regression analysis to the starved E.H.L. question, this new inlet distance parameter enables a seminumerical formula for the prediction of the starved isothermal and nonisothermal rolling traction to be derived. The formula applies for a starved E.H.L. line contact and covers a wide range of the nondimensional materials, thermal loading, speed, load and inlet distance variables. A numerical example using several of the equations developed in this paper has been included in Appendix 1. For the isothermal case, the general formula developed shows good agreement with the two specific semianalytical results reported by Archard and Baglin [11], 1975.

Correlation between FA and ADC, number and length of the periprostatic neurovascular fibers

2021 ◽  
pp. 039156032110637
Author(s):  
Valerio Di Paola ◽  
Angelo Totaro ◽  
Giacomo Avesani ◽  
Benedetta Gui ◽  
Andrea Boni ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Negative Correlation ◽  
Multivariate Regression ◽  
Linear Regression Analysis ◽  
Multivariate Linear Regression ◽  
Multivariate Linear Regression Analysis ◽  
Independent Variables ◽  
Fiber Tracts ◽  
Good Agreement

Purpose: Our aim was to explore the relation between FA and ADC, number and length of the periprostatic neurovascular fibers (PNF) by means of 1.5 T Diffusion Tensor Imaging (DTI) imaging through a multivariate linear regression analysis model. Methods: For this retrospective study, 56 patients (mean age 63.5 years), who underwent 1.5-T prostate MRI, including DTI, were enrolled between October 2014 and December 2018. Multivariate regression analysis was performed to evaluate the statistically significant correlation between FA values (dependent variable) and ADC, the number and the length of PNF (independent variables), if p-value <0.05. A value of 0.5 indicated poor agreement; 0.5–0.75, moderate agreement; 0.75–0.9, good agreement; 0.61–0.80, good agreement; and 0.9–1.00, excellent agreement. Results: The overall fit of the multivariate regression model was excellent, with R2 value of 0.9445 ( R2 adjusted 0.9412; p < 0.0001). Multivariate linear regression analysis showed a statistically significant correlation ( p < 0.05) for all the three independent variables. The r partial value was −0.9612 for ADC values ( p < 0.0001), suggesting a strong negative correlation, 0.4317 for the number of fiber tracts ( p < 0.001), suggesting a moderate positive correlation, and −0.306 for the length of the fiber tracts ( p < 0.05), suggesting a weak negative correlation. Conclusions: Our multivariate linear regression model has demonstrated a statistically significant correlation between FA values of PNF with other DTI parameters, in particular with ADC.

scholarly journals Reliability of Nitrogen Content (%N) and Carbon:Nitrogen Atomic Ratios (C:N) as Indicators of Collagen Preservation Suitable for Radiocarbon Dating

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 879-886 ◽  
Author(s):  
Fiona Brock ◽  
Rachel Wood ◽  
Thomas F G Higham ◽  
Peter Ditchfield ◽  
Alex Bayliss ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Radiocarbon Dating ◽  
Linear Regression Analysis ◽  
Atomic Weight ◽  
Animal Bones ◽  
Bone Powder ◽  
Wide Range ◽  
Pass Through ◽  
Percent Nitrogen

A recent study into prescreening techniques to identify bones suitable for radiocarbon dating from sites known for poor or variable preservation (Brock et al. 2007, 2010a) found that the percent nitrogen (%N) content of whole bone powder was the most reliable indicator of collagen preservation. Measurement of %N is rapid, requires little preparation or material, and is relatively cheap. The technique reduces the risk of needlessly sampling valuable archaeological objects, as well as saving time and money on their unsuccessful pretreatment prior to dating. This method of prescreening is now regularly used at the Oxford Radiocarbon Accelerator Unit (ORAU). In the original study, linear regression analysis of data from 100 bones from 12 Holocene sites across southern England showed that when 0.76% N was chosen as a threshold, 84% of bones were successfully identified as containing sufficient (i.e. >1%) or insufficient (i.e. <1%) collagen for dating. However, it has been observed that for older, Pleistocene bones the failure rate may be higher, possibly due to the presence of more degraded, short-chain proteins that pass through the ultrafilters used in pretreatment, resulting in lower yields. Here, we present linear regression analysis of data from nearly 600 human and animal bones, antlers, and teeth, from a wide range of contexts and ages, to determine whether the 0.76% threshold identified in the previous study is still applicable. The potential of carbon:nitrogen atomic weight ratios (C:N) of whole bone to predict collagen preservation is also discussed.

Evaluation and comparison of a radiative energy attenuation method for determining cholesterol in serum.

1985 ◽  
Vol 31 (4) ◽  
pp. 605-608 ◽  
Author(s):  
P L Cary ◽  
C A Johnson ◽  
P D Whitter ◽  
J W Parker
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
High Performance ◽  
Linear Regression Analysis ◽  
Radiative Energy ◽  
Comparison Methods ◽  
Analytical Recovery ◽  
Wide Range

Abstract Determination of cholesterol by a radiative energy attenuation (REA) technique was evaluated and compared with results obtained by the Boehringer Mannheim High Performance Cholesterol Assay and the Du Pont aca. Within-assay and between-assay CVs for the REA method, for two sets of controls, were both less than 5%. We observed no interference with lipemic samples. Analytical recovery averaged 102.8%. We used all three methods for parallel determinations of 217 patients' samples containing a wide range of cholesterol concentrations. Linear regression analysis of the REA results vs those of the comparison methods were as follows: REA = 1.03 Boehringer - 0.072 (r = 0.993) and REA = 1.02 aca - 0.048 (r = 0.995). We also discuss bilirubin interference with the REA method for cholesterol.

The Effect of Viscous Shear Heating on Both Film Thickness and Rolling Traction in an EHL Line Contact—Part II: Starved Conditions

1978 ◽  
Vol 100 (3) ◽  
pp. 353-358 ◽  
Author(s):  
P. G. Goksem ◽  
R. A. Hargreaves
Keyword(s):  
Theoretical Analysis ◽  
Film Thickness ◽  
Approximate Equation ◽  
Theoretical Work ◽  
Line Contact ◽  
Viscous Shear ◽  
Isothermal Case ◽  
Shear Heating ◽  
Boundary Distance ◽  
Contact Part

A theoretical analysis of both fully flooded rolling traction and film thickness in an EHL line contact has been presented in Part I of this paper. The effect of viscous shear heating was investigated and the results predict a significant reduction in both fully flooded film thickness and rolling traction, relative to the isothermal case, as speed is increased. In this part of the Series, the analysis is extended to consider the calculation of starved rolling traction and film thickness, including viscous shear heating of the lubricant in the inlet region. An approximate equation has been developed, which predicts both the isothermal and non isothermal starved film thickness for all conditions of inlet boundary distance, rolling speed, load, geometry, material constants and lubricant properties. The results show that both rolling traction and film thickness are significantly reduced from the starved isothermal case. For the starved isothermal case, the theoretical analysis for the film thickness agrees closely with experimental data and published empirical formula by Wymer and Cameron, (1974) and the theoretical work of Wolveridge, et al. (1971).

scholarly journals Relationship between the 0.01 M CaCl2- and AL-soluble soil phosphorus contents

2018 ◽  
Vol 67 (1) ◽  
pp. 23-33
Author(s):  
Emese Szabó ◽  
László Huzsvai ◽  
Rita Kremper ◽  
Jakab Loch
Keyword(s):  
Regression Analysis ◽  
Soil Properties ◽  
Soil Phosphorus ◽  
Linear Regression Analysis ◽  
Extraction Methods ◽  
Soil Parameters ◽  
Regression Equations ◽  
Weak Correlation ◽  
Ammonium Lactate ◽  
Wide Range

The traditional Hungarian method for determining soil phosphorus (P) status is ammonium-lactate acetic acid (AL) extraction. AL is an acidic solution (buffered at pH 3.75), which is also able to dissolve P reserves, so there is a need for extraction methods that also characterize the mobile P pool. 0.01 M CaCl2-P is considered to directly describe available P forms, because the dilute salt solution has more or less the same ionic strength as the average salt concentration in many soil solutions. The amount of AL-P may be two orders of magnitude greater than that of CaCl2-P. Previous studies suggested that the relationship between AL-P and CaCl2-P was influenced by soil parameters. Regression analysis between AL-P and CaCl2-P showed medium or strong correlations when using soils with homogeneous soil properties, while there was a weak correlation between them for soils with heterogeneous properties. The objective of this study was to increase the accuracy of the conversion between AL-P and CaCl2-P, by constructing universal equations that also take soil properties into consideration. The AL-P and CaCl2-P contents were measured in arable soils (n=622) originating from the Hungarian Soil Information and Monitoring System (SIMS). These soils covered a wide range of soil properties. A weak correlation was found between AL-P and CaCl2-P in SIMS soils. The amounts and ratio of AL-P and CaCl2-P depended on soil properties such as CaCO3 content and texture. The ratio of AL-P to CaCl2-P changed from 37 in noncalcareous soils to 141 on highly calcareous soils. CaCl2-P decreased as a function of KA (plasticity index according to Arany), which is related to the clay content, while the highest AL-P content was found on loam soils, probably due to the fact that a high proportion of them were calcareous. The relationships between AL-P, CaCl2-P and soil properties in the SIMS dataset were evaluated using multiple linear regression analysis. In order to select the best model the Akaike Information Criterion (AIC) was used to compare different models. The soil factors included in the models were pHKCl, humus and CaCO3 content to describe AL-P, and KA, CaCO3 content and pHKCl to describe CaCl2-P. AL-P was directly proportional to pHKCl, humus and CaCO3 content, while CaCl2-P was inversely proportional to KA, CaCO3 content and pHKCl. The explanatory power of the models increased when soil properties were included. The percentage of the explained variance in the AL-P and CaCl2-P regression models was 56 and 51%, so the accuracy of the conversion between the two extraction methods was still not satisfactory and it does not seem to be possible to prepare a universally applicable equation. Further research is needed to obtain different regression equations for soils with different soil properties, and CaCl2-P should also be calibrated in long-term P fertilization trials.

Abbott radiative energy attenuation method for quantifying ethanol evaluated and compared with gas-liquid chromatography and the Du Pont aca.

1984 ◽  
Vol 30 (11) ◽  
pp. 1867-1870 ◽  
Author(s):  
P L Cary ◽  
P D Whitter ◽  
C A Johnson
Keyword(s):  
Regression Analysis ◽  
Liquid Chromatography ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Method Comparison ◽  
Cross Reactivity ◽  
Radiative Energy ◽  
Gas Liquid Chromatography ◽  
Analytical Recovery ◽  
Wide Range

Abstract Quantification of ethanol by a radiative energy attenuation (REA) technique was evaluated and compared with results by gas-liquid chromatography (GLC) and by the Du Pont aca. Within-assay CVs were less than 5.5%. Between-assay CVs ranged from 1.9% to 6.0% for serum and blood controls at concentrations of 0.5, 1.0, and 2.5 g/L. We observed no cross reactivity with methanol, isopropanol, or acetone, and analytical recovery of ethanol from serum averaged 101%. For the three-method comparison we performed parallel determinations of 156 blood, 92 serum, and 54 urine samples containing a wide range of ethanol concentrations. Linear regression analysis of the REA results vs those of GLC or aca yielded the following: for serum, REA = 1.03 GLC -0.03 (r = 0.998), REA = 1.13 aca -0.04 (r = 0.999); for blood, REA = 0.97 GLC + 0.05 (r = 0.994), REA = 0.99 aca + 0.06 (r = 0.996); and for urine, REA = 1.01 GLC -0.03 (r = 0.998). We also discuss the clinical and forensic use of the REA method for ethanol.

Kinematics-Based Determination of the Rolling Region in Roll Bending for Smoothly Curved Plates

2000 ◽  
Vol 123 (2) ◽  
pp. 284-290 ◽  
Author(s):  
Jong Gye Shin ◽  
Joon Tae Park ◽  
Hyunjune Yim
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Systematic Approach ◽  
Linear Regression Analysis ◽  
Forming Process ◽  
Roll Bending ◽  
Bending Process ◽  
Curvature Distribution ◽  
Good Agreement

This paper proposes and develops a kinematics-based, systematic approach to determine the region of a plate to be rolled, in order to fabricate smoothly curved plates. The approach includes a kinematic analysis to calculate the plate’s curvature distribution, and, in addition, a linear regression analysis to determine the initial and final locations of the roller during the roll bending process. Three artificial cases and two real cases have been studied, and the results are in good agreement with field practices. This approach will play an important role in the automation and optimization of the plate forming process.

scholarly journals P761 Illness cognition of Saudi patients with Crohn’s disease

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S606-S606
Author(s):  
M H A Mosli ◽  
A Saeedi ◽  
M ALNEFAIE ◽  
N Bawahab ◽  
L Abdu ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Linear Regression ◽  
Linear Regression Analysis ◽  
Considerable Proportion ◽  
Illness Cognition ◽  
Wide Range ◽  
The Mean ◽  
Saudi Patients

Abstract Background The prevalence of Crohn’s disease (CD) has markedly increased in Saudi Arabia over the past 3 decades.Patients’ awareness of the chronic recurrent course and potential risk of disease complications can lead to a wide range of psychological and interpersonal concerns. Patients’ cognition about the disease and treatment are important mediators as they explain the occurrence of individual differences in the individuals’ adjustment to chronic diseases. The aim of this study is to assess illness cognition of Saudi patients diagnosed with CD and to identify clinical predictors. Methods Consecutive patients with confirmed CD seen in the adult outpatient gastroenterology clinic at King Abdulaziz university hospital were recruited between January and December of 2019. Data was collected from interviews conducted with the patients and from the hospitals’ electronic medical records.The primary endpoint of the study was patients’ illness cognition according to the illness cognition questionnaire (ICQ), which can be used to assess three cognitive functions that patients attribute to disease: helplessness (6 items), acceptance (6 items), and perceived benefits (6 items). Each item is scored from 1 to 4, with 1 corresponding to ‘Not’, and 4 corresponding to ‘Totally. Descriptive statistics were used to summarise patient characteristics and linear regression analysis was used to identify predictors of the ICQ score. Results A total of 88 patients were surveyed, of which 55.8% were females, 18% were smokers and 11.5% had undergone CD-related surgery. The mean age was 26.9 ± 7.7 years and the mean duration of disease was 54.7 ± 60.5 months. Perianal disease was reported by 16.1% of the cohort. Twenty eight percent of patients reported that they ‘completely’ missed things that they like to do the most because of their illness and 35% responded by ‘not at all’ when asked if they had learned to live with their disease. Forty one percent of patients reported that the illness ‘completely’ controls their life and 30% responded by ‘not at all’ when asked if they can accept their illness. Mean ICQ score was 44.3 ( ± 6.6). On linear regression analysis, duration of the disease in months (coef = −0.04, p = 0.008) and fatigue (coef = −1.40, p = 0.04) were predictive of the ICQ score. Conclusion A considerable proportion of Saudi patients diagnosed with CD report negative perception of their disease. Duration of illness and presence of fatigue appear to be predictive of the ICQ score.

Prevalence and Predictors of Fruit Intake Among Community College Women in the Extended Opportunity Program and Services

2003 ◽  
Vol 1 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Steve E. Shive ◽  
Michelle R. Neyman
Keyword(s):  
Community College ◽  
Weight Loss ◽  
Regression Analysis ◽  
College Women ◽  
Linear Regression Analysis ◽  
Good Health ◽  
Fruit Intake ◽  
Attitudes And Behaviors ◽  
Eating Fruit ◽  
Opportunity Program

This study examined fruit intake among 276 female Extended Opportunity Program and Services (EOPS) community college students. Knowledge, attitudes, and behaviors associated with fruit intake were determined. The attitudes which are potential predictors of daily fruit intake were also examined. Analysis showed that 33% ate fewer than the minimum recommended two daily servings of fruit. Students reported that fruit gave them energy, taste and cost were not barriers to consumption and that it would not be difficult to increase daily fruit consumption. A linear regression analysis revealed that beliefs that eating fruit leads to good health, having a habit of eating fruit, feeling energy, and weight loss accounted for 30% of the variance in fruit intake.

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