Establishing Correlation between Leaf Spring Specifications and Camber Drop

Manufacturing of leaf spring for automotive application to support heavy load vehicles such lorry and truck is a challenging process. This is due to the difficulty in fabricating the leaf spring exactly as per designed. The difference between the desired leaf spring shape and the actual fabricated shape is known as camber drop. The aim of this study is to establish the correlation between leaf spring specifications, camber drop and its processing parameters. The formulated equation can thus be used to predict the extent of camber drop and required action can be taken to reduce camber drop. This work was conducted by gathering data of variables suspected to influence camber drop, namely quenching camber, half-length of the spring, spring rate and end thickness of the spring. Regression analysis was conducted and the correlation between leaf spring’s specifications and camber drop is given. A mathematical model able to predict the extent of camber drop is formulated.

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Changes in Children’s Body Composition and Posture during Puberty Growth

Children ◽

10.3390/children8040288 ◽

2021 ◽

Vol 8 (4) ◽

pp. 288

Author(s):

Wojciech Rusek ◽

Joanna Baran ◽

Justyna Leszczak ◽

Marzena Adamczyk ◽

Rafał Baran ◽

...

Keyword(s):

Body Composition ◽

Adipose Tissue ◽

Regression Analysis ◽

Body Mass ◽

Pelvic Obliquity ◽

The Body ◽

Body Posture ◽

Older Children ◽

The Difference ◽

The Right

The main goal of our study was to determine how the age of children, puberty and anthropometric parameters affect the formation of body composition and faulty body posture development in children. The secondary goal was to determine in which body segments abnormalities most often occur and how gender differentiates the occurrence of adverse changes in children’s body posture and body composition during puberty. The study group consisted of 464 schoolchildren aged from 6–16. Body posture was assessed with the Zebris system. The composition of the body mass was tested with Tanita MC 780 MA body mass analyzer and the body height was measured using a portable stadiometer PORTSTAND 210. The participants were further divided due to the age of puberty. Tanner division was adopted. The cut-off age for girls is ≥10 years and for boys it is ≥12 years. The analyses applied descriptive statistics, the Pearson correlation, stepwise regression analysis and the t-test. The accepted level of significance was p < 0.05. The pelvic obliquity was lower in older children (beta = −0.15). We also see that age played a significant role in the difference in the height of the right pelvis (beta = −0.28), and the difference in the height of the right shoulder (beta = 0.23). Regression analysis showed that the content of adipose tissue (FAT%) increased with body mass index (BMI) and decreased with increasing weight, age, and height. Moreover, the FAT% was lower in boys than in girls (beta negative equal to −0.39). It turned out that older children (puberty), had greater asymmetry in the right shoulder blade (p < 0.001) and right shoulder (p = 0.003). On the other hand, younger children (who were still before puberty) had greater anomalies in the left trunk inclination (p = 0.048) as well as in the pelvic obliquity (p = 0.008). Girls in puberty were characterized by greater asymmetry on the right side, including the shoulders (p = 0.001), the scapula (p = 0.001) and the pelvis (p < 0.001). In boys, the problem related only to the asymmetry of the shoulder blades (p < 0.001). Girls were characterized by a greater increase in adipose tissue and boys by muscle tissue. Significant differences also appeared in the body posture of the examined children. Greater asymmetry within scapulas and shoulders were seen in children during puberty. Therefore, a growing child should be closely monitored to protect them from the adverse consequences of poor posture or excessive accumulation of adipose tissue in the body.

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Numerical Simulation of Effect of Different Initial Morphologies on Melt Hydrodynamics in Laser Polishing of Ti6Al4V

Micromachines ◽

10.3390/mi12050581 ◽

2021 ◽

Vol 12 (5) ◽

pp. 581

Author(s):

Kai Li ◽

Zhenyu Zhao ◽

Houming Zhou ◽

Hao Zhou ◽

Jie Yin ◽

...

Keyword(s):

Flow Behavior ◽

Processing Parameters ◽

Surface Finishing ◽

Polished Surface ◽

Laser Polishing ◽

Starting Position ◽

Double Spiral ◽

The Difference ◽

Thermocapillary Forces ◽

Surface Morphologies

As a surface finishing technique for rapid remelting and re-solidification, laser polishing can effectively eliminate the asperities so as to approach the feature size. Nevertheless, the polished surface quality is significantly sensitive to the processing parameters, especially with respect to melt hydrodynamics. In this paper, a transient two-dimensional model was developed to demonstrate the molten flow behavior for different surface morphologies of the Ti6Al4V alloy. It is illustrated that the complex evolution of the melt hydrodynamics involving heat conduction, thermal convection, thermal radiation, melting and solidification during laser polishing. Results show that the uniformity of the distribution of surface peaks and valleys can improve the molten flow stability and obtain better smoothing effect. The high cooling rate of the molten pool resulting in a shortening of the molten lifetime, which prevents the peaks from being removed by capillary and thermocapillary forces. It is revealed that the mechanism of secondary roughness formation on polished surface. Moreover, the double spiral nest Marangoni convection extrudes the molten to the outsides. It results in the formation of expansion and depression, corresponding to nearby the starting position and at the edges of the polished surface. It is further found that the difference between the simulation and experimental depression depths is only about 2 μm. Correspondingly, the errors are approximately 8.3%, 14.3% and 13.3%, corresponding to Models 1, 2 and 3, respectively. The aforementioned results illustrated that the predicted surface profiles agree reasonably well with the experimentally measured surface height data.

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Mathematical Model of the Sintering Process of Iron-Copper Bearings

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.23.119 ◽

2007 ◽

Vol 23 ◽

pp. 119-122

Author(s):

Cristina Teișanu ◽

Stefan Gheorghe ◽

Ion Ciupitu

Keyword(s):

Experimental Data ◽

Mechanical Properties ◽

Mathematical Model ◽

Regression Analysis ◽

Function Optimization ◽

Chemical Compositions ◽

Sintering Process ◽

Molybdenum Disulphide ◽

Iron Copper ◽

Antifriction Properties

The most important features of the self-lubricating bearings are the antifriction properties such as friction coefficient and wear resistence and some mechanical properties such as hardness, tensile strength and radial crushing strength. In order to improve these properties new antifriction materials based on iron-copper powders with several additional components (tin, lead and molybdenum disulphide) have been developed by PM techniques. To find the optimal relationship between chemical compositions, antifriction and mechanical properties, in this paper a mathematical model of the sintering process is developed, which highlighted the accordance of the model with data by regression analysis. For the statistical processing of the experimental data the VH5 hardness values of the studied materials were considered. The development of mathematical model includes the enunciation of the model, the establishment of the performance function (optimization) and the establishment of the model equations and verifying. The accordance of the model with experimental data has been highlighted by regression analysis

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Study on Sputtering Characteristics of Ni80Cr20 Alloy Target

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.1891 ◽

2007 ◽

Vol 353-358 ◽

pp. 1891-1894

Author(s):

Zhi Yong He ◽

Xiao Feng Wang ◽

Ying Fan ◽

Zhen Xia Wang ◽

Xiao Ping Liu ◽

...

Keyword(s):

Regression Analysis ◽

Glow Discharge ◽

Processing Parameters ◽

Orthogonal Test ◽

Real Output ◽

Target Temperature ◽

Alloy Target ◽

Discharge Parameters ◽

Sputtering Yield ◽

Discharge Pressure

Sputtering rate Sr was proposed as an alternative parameter instead of sputtering yield Y to calibrate the sputtering ability of the target, defined as the mass loss of the target per unit time and sputtering current. The approach is more reliable for glow discharge processes since the intense backscattering effect was taken into consideration. The effects of processing parameters on Sr were investigated through orthogonal test, the results indicated that target temperature affects Sr obviously, and among the discharge parameters, the target voltage and discharge pressure were the governing factors. Through regression analysis, the sputtering rate Sr was expressed as a function of sputtering voltage and discharge pressure which could be used to evaluate or predict the real output of the sputtering target.

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Analysis on Kinematic Characteristics of Precision Balls Grinding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.497.20 ◽

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.

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Impact of multilayered compression bandages on sub-bandage interface pressure: a model

Phlebology The Journal of Venous Disease ◽

10.1258/phleb.2010.009081 ◽

2011 ◽

Vol 26 (2) ◽

pp. 75-83 ◽

Cited By ~ 19

Author(s):

J Al Khaburi ◽

E A Nelson ◽

J Hutchinson ◽

A A Dehghani-Sanij

Keyword(s):

Mathematical Model ◽

Thick Wall ◽

Compression Bandage ◽

Leg Ulcers ◽

Interface Pressure ◽

Venous Leg Ulcers ◽

Compression Bandages ◽

Thick Cylinder ◽

The Difference ◽

Interface Pressures

Background Multi-component medical compression bandages are widely used to treat venous leg ulcers. The sub-bandage interface pressures induced by individual components of the multi-component compression bandage systems are not always simply additive. Current models to explain compression bandage performance do not take account of the increase in leg circumference when each bandage is applied, and this may account for the difference between predicted and actual pressures. Objective To calculate the interface pressure when a multi-component compression bandage system is applied to a leg. Method Use thick wall cylinder theory to estimate the sub-bandage pressure over the leg when a multi-component compression bandage is applied to a leg. Results A mathematical model was developed based on thick cylinder theory to include bandage thickness in the calculation of the interface pressure in multi-component compression systems. In multi-component compression systems, the interface pressure corresponds to the sum of the pressures applied by individual bandage layers. However, the change in the limb diameter caused by additional bandage layers should be considered in the calculation. Adding the interface pressure produced by single components without considering the bandage thickness will result in an overestimate of the overall interface pressure produced by the multi-component compression systems. At the ankle (circumference 25 cm) this error can be 19.2% or even more in the case of four components bandaging systems. Conclusion Bandage thickness should be considered when calculating the pressure applied using multi-component compression systems.

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Dynamics Analysis of a Mathematical Model for New Product Innovation Diffusion

Discrete Dynamics in Nature and Society ◽

10.1155/2020/4716064 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Chunru Li ◽

Zujun Ma

Keyword(s):

Mathematical Model ◽

Time Delay ◽

Media Coverage ◽

New Product ◽

Normal Form Theory ◽

Center Manifold Theorem ◽

Significant Difference ◽

Form Theory ◽

The Difference ◽

The Stability

In this paper, a mathematical model with time-delay-related parameters and media coverage to describe the diffusion process of new products is proposed, in which the time-delay-related parameters denote the stage in which potential customers decide whether to adopt a new product. Then, the stability and the Hopf bifurcation of the proposed model are analyzed in detail. The center manifold theorem and the normal form theory are used to investigate the stability of the bifurcating periodic solution. Moreover, a numerical simulation is conducted to investigate the difference between the model with delay-dependent parameters and that with delay-independent parameters. The results show that there is significant difference between the two models.

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Intraocular Lens Power Calculation According to the Difference between Anterior and Total Keratometry Using Scheimpflug Imaging

Journal of the Korean Ophthalmological Society ◽

10.3341/jkos.2021.62.9.1181 ◽

2021 ◽

Vol 62 (9) ◽

pp. 1181-1188

Author(s):

Joong Hee Kim ◽

Kyong Jin Cho ◽

Ho Seok Chung

Keyword(s):

Regression Analysis ◽

Absolute Error ◽

Power Calculation ◽

Intraocular Lens Power Calculation ◽

Refractive Power ◽

Simple Regression Analysis ◽

The Absolute ◽

The Difference ◽

Lens Power ◽

Simple Regression

Purpose: We investigated the change in the absolute error according to the difference between anterior and total keratometry, to determine the criterion for the difference in keratometry, and to determine the indication for using total keratometry. Methods: Sagittal and total refractive power were measured with 2-, 3-, and 4-mm Pentacam® rings, and the absolute error of each was calculated in patients who underwent cataract surgery in our hospital. The correlation between the difference value the sagittal minus the total refractive power and each absolute error was analyzed by simple regression analysis. The analysis was performed by dividing the patients into two groups based on 0.6, which is the average of the difference between the sagittal and total refractive power for the 3-mm ring. Results: Sagittal power was larger than total refractive power for all rings and the absolute error obtained by applying the total refractive power was larger than the sagittal power for the 2- and 4-mm rings (p < 0.001). The simple regression analysis revealed that the absolute error using sagittal power was positively correlated with the difference between sagittal power and total refractive power. In the group with less than 0.6, the absolute error using the total refractive power of all rings was larger than the sagittal power (p < 0.001). In the group exceeding 0.6, the absolute error using the total refractive power was less than using the sagittal power for the 3 mm ring (p = 0.028). Conclusions: The greater the difference between sagittal and total refractive power, the greater the absolute error using sagittal power. Accuracy was higher in the group exceeding 0.6 after applying total refractive power measured at the 3 mm ring compared to sagittal power.

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The Presence of Limited Joint Mobility Is Significantly Associated with Multiple Digit Involvement by Stenosing Flexor Tenosynovitis in Diabetics

The Journal of Rheumatology ◽

10.3899/jrheum.081024 ◽

2009 ◽

Vol 36 (8) ◽

pp. 1686-1690 ◽

Cited By ~ 21

Author(s):

MAKOTO KAMEYAMA ◽

SHU MEGURO ◽

OSAMU FUNAE ◽

YOSHIHITO ATSUMI ◽

HIROYASU IKEGAMI

Keyword(s):

Regression Analysis ◽

Multiple Regression Analysis ◽

Multiple Regression ◽

Diabetic Patients ◽

Joint Mobility ◽

Limited Joint Mobility ◽

Chi Squared ◽

Tunnel Syndrome ◽

The Difference ◽

Flexor Tenosynovitis

Objective.Diabetes is associated with several disorders of the hand, including stenosing flexor tenosynovitis (SFTS). The feature of SFTS in diabetics is a higher prevalence of multiple digit involvement. We examined the magnitude of the tendency for involvement of more digits by SFTS in diabetic patients than in nondiabetic patients, and attempted to clarify the factors influencing multiple digit involvement by SFTS in diabetics.Methods.The study comprised 302 diabetic patients with SFTS and 235 nondiabetic patients with SFTS. The total number of digits exhibiting SFTS within the 1-year period following the initial visit to the Department of Orthopaedic Surgery was investigated in a prospective manner. We compared the difference in the frequency of multiple digit involvement by SFTS between diabetic and nondiabetic patients using the chi-squared test. Multiple regression analysis was performed to examine the contribution of independent variables [defined as 12 factors including age, sex, type of diabetes, estimated duration of diabetes, HbA1c values, carpal tunnel syndrome, Dupuytren contracture, limited joint mobility (LJM), de Quervain's disease, diabetic retinopathy, diabetic nephropathy, and dyslipidemia] to the total number of digits affected by SFTS in diabetic patients.Results.Diabetic patients showed a significantly higher prevalence of multiple digit involvement than nondiabetic patients (p < 0.0001). Multiple regression analysis in diabetic patients revealed that the presence of LJM was positively associated with the prevalence of multiple digit involvement (r = 0.626, p < 0.0001).Conclusion.LJM in diabetics is closely associated with SFTS involving multiple digits.

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The Influence of Water and Mineral Oil On Volumetric Losses in a Hydraulic Motor

Polish Maritime Research ◽

10.1515/pomr-2017-0041 ◽

2017 ◽

Vol 24 (s1) ◽

pp. 213-223 ◽

Cited By ~ 5

Author(s):

Pawel Śliwiński

Keyword(s):

Mathematical Model ◽

Rotational Speed ◽

Experimental Studies ◽

Experimental Tests ◽

Mineral Oil ◽

Hydraulic Motor ◽

Small Constant ◽

Influence Of Water ◽

The Difference ◽

Lubricating Properties

Abstract In this paper volumetric losses in hydraulic motor supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted using an innovative hydraulic satellite motor, that is dedicated to work with different liquids, including water. The sources of leaks in this motor are also characterized and described. On this basis, a mathematical model of volumetric losses and model of effective rotational speed have been developed and presented. The results of calculation of volumetric losses according to the model are compared with the results of experiment. It was found that the difference is not more than 20%. Furthermore, it has been demonstrated that this model well describes in both the volumetric losses in the motor supplied with water and oil. Experimental studies have shown that the volumetric losses in the motor supplied with water are even three times greater than the volumetric losses in the motor supplied with oil. It has been shown, that in a small constant stream of water the speed of the motor is reduced even by half in comparison of speed of motor supplied with the same stream of oil.

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