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Fuel ◽  
2022 ◽  
Vol 314 ◽  
pp. 123053
Author(s):  
Zhiming Chen ◽  
Dexuan Li ◽  
Shaoqi Zhang ◽  
Xinwei Liao ◽  
Biao Zhou ◽  
...  

2022 ◽  
Vol 18 (1) ◽  
pp. 141-159
Author(s):  
Yuniar Fitriyani

The purpose of this study was to analyze the effect of independent variables, profitability proxied by Return On Equity (ROE) and solvency proxied by Debt to Assets Ratio (DAR) on the dependent variable, namely stock prices. The population in this study were 45 companies in the LQ45 category listed on the Indonesia Stock Exchange. Sampling in this study using purposive sampling method, namely as many as 31 companies that are consistently indexed LQ45 on the Indonesia Stock Exchange (IDX) during the 2015-2019 period with the amount of data processed after the outlier process as many as 129 samples. The analysis test model used in this hypothesis is multiple linear regression analysis. The results showed that profitability (ROE) had no effect on stock prices, solvency (DAR) had no effect on stock prices, and simultaneously (ROE) and solvency (DAR) had no effect on company stock prices. Keywords: Stock Price, Return on Equity (ROE), Debt to Assets Ratio (DAR)


2022 ◽  
Author(s):  
Katherine M Steele ◽  
Michael H Schwartz

Background Altered motor control is common in cerebral palsy (CP). Understanding how altered motor control effects movement and treatment outcomes is important, but challenging due to complex interactions between impairments. While regression can be used to examine associations between impairments and gait, causal modeling provides a mathematical framework to specify assumed causal relationships, identify covariates that may introduce bias, and test model plausibility. The goal of this research was to quantify the causal effects of altered motor control and other impairments on gait, before and after single-event multi-level orthopedic surgery (SEMLS). Methods We evaluated the impact of SEMLS on change in Gait Deviation Index (GDI) between gait analyses. We constructed our causal model with a Directed Acyclic Graph that included the assumed causal relationships between SEMLS, change in GDI, baseline GDI (GDIpre), baseline neurologic and orthopedic impairments (Imppre), age, and surgical history. We identified the adjustment set to evaluate the causal effect of SEMLS on change in GDI and the impact of Imppre on change in GDI and GDIpre. We used Bayesian Additive Regression Trees (BART) and accumulated local effects to assess relative effects. Results We prospectively recruited a cohort of children with bilateral CP undergoing SEMLS (N=54, 35 males, age: 10.5+/-3.1 years) and identified a control cohort with bilateral CP who did not undergo SEMLS (N=55, 30 males, age: 10.0+/-3.4 years). There was a small positive causal effect of SEMLS on change in GDI (1.68 GDI points). Altered motor control (i.e., dynamic and static motor control) and strength had strong effects on GDIpre, but minimal effects on change in GDI. Spasticity and orthopedic impairments had minimal effects on GDIpre or change in GDI. Conclusions Altered motor control and other baseline impairments did have a strong effect on GDIpre, indicating that these impairments do have a causal effect on a child's gait pattern but minimal effect on expected changes in GDI after SEMLS. Heterogeneity in outcomes suggests there are other factors contributing to changes in gait. Identifying these factors and employing causal methods to examine the complex relationships between impairments and movement will be required to advance our understanding and care of children with CP.


2022 ◽  
Vol 9 ◽  
Author(s):  
Dong Feng ◽  
Enke Hou ◽  
Xiaoshen Xie ◽  
Xiaoyang Che ◽  
Pengfei Hou ◽  
...  

Groundwater leakage in the loess gully terrain is one of the main hazards of coal seam mining at shallow burial depth. The burial depth of the 5−2 coal seam is less than 50 m from the ground in the gully of the study site. The fissures that expand upward after mining can easily penetrate the ground to form a water-conducting channels. During rainy periods, there is a potential risk of groundwater leakage. In order to reveal the characteristics of plane development and the dynamic evolution of gully ground fissures, the typical U-shaped gully in the northern Shaanxi coal mine was studied using the field measurement methods of “On-site measurement” and UAV aerial photography. Based on the experimental platform of ground fissure leakage developed and designed by the team, an indoor test model corresponding to the actual situation was established. In addition, the mathematical models of actual flood inrush, fissure width, and flood flow in the channel were established. The actual mine water flow and the mine drainage capacity were compared and analyzed, thus proposing criteria for classifying gully mining ground fissure collapsed water hazards. These criteria can provide theoretical references for predicting fissure leakage hazard zones in the ground gully of shallow buried coal seams. According to the development height of the water-conducting fissure zone (WCFZ), the treatment methods of ground fissures in gullies under different security conditions were designed, which was applied in the field with good results. The results showed that the treatment methods in this paper could effectively prevent the leakage of groundwater in the gullies along the ground fissures.


2022 ◽  
Vol 2148 (1) ◽  
pp. 012035
Author(s):  
Yali Liu ◽  
Jun Dong ◽  
Guohua Li ◽  
Xi Chen ◽  
Yunkai Zhang

Abstract Due to warpage and ballooning of high-speed rail track slab caused by debonding and environmental temperature changes during the deterioration of CA mortar layer being extremely concerned in practical engineering, it is based on numerical simulation of typical working conditions and analysis of test model that the deformation dynamics mechanism of track slab of high-speed rail in service is studied in this paper. Firstly, three kinds of damage conditions of CA mortar layer are designed to simulate the partial stress state of track slab under normal, warping and bulging conditions, and the results of model test are compared with those of finite element analysis so that the accuracy and credibility of the numerical simulation method and results are verified. Then, through finite element numerical simulation, the dynamical mechanism of actual full-scale high-speed rail track slab under vibration load is studied. The results show that the warping deformation around the track slab and the bulging deformation in the middle part under the action of positive and negative temperature gradient load caused by environmental temperature change will have a great impact on the structural performance of itself and CA mortar layer; Bulging deformation of track slab is more destructive to its structure than warping deformation. It is of great practical significance to further study the critical position of track plate warpage and bulging deformation, and to optimize and strengthen the structure of this part; The research results are of great significance to further study the deterioration.


2021 ◽  
Vol 15 (1) ◽  
pp. 742-747
Author(s):  
John B. Bridgman ◽  
Andrew L. Newsom ◽  
David J. Chrisp ◽  
Abi E. Estelle ◽  
Mark Saunders

Aim: A pilot study was conducted with the aim of developing a system to protect the eyes, nose, and mouth from the aerosol generated from a high-speed dental handpiece during the COVID-19 pandemic. Background: The SARS-CoV-2 virus is known to be present in the saliva of an infected individual during the contagious viral shedding phase of the disease. The use of rotary dental instruments places oral health practitioners at risk of contracting COVID-19 from infected individuals. In particular, it is very difficult to protect the mucous membranes of the face against the extremely fine aerosol produced from a high-speed dental handpiece. Objectives: This study aimed to develop and test a novel PPE system for use during the COVID-19 pandemic. An air-fed spray-painting mask was used under a plastic hood to protect against the aerosol from a high-speed dental handpiece. This was found to be superior compared to hospital-issued N-95 masks and eye protection in our test model. Methods: Subjects donned various forms of PPE whilst using a high-speed dental handpiece in a confined cubicle. The efficacy of each form of PPE was evaluated by adding fluorescein to the water coolant supply line of a high-speed dental handpiece before checking for facial contamination with an ophthalmology slit lamp. Results: Under our test conditions, the N-95 mask did not prevent nasal and mouth contaminations, but the combination of an air-fed mask with a sealed hood prevented these contaminations. Although goggles worn tightly did prevent contamination, the air-fed mask system was far more comfortable and did not fog up. Discussion: Under the rigorous test conditions of our model, we found hospital-issued PPE ineffective. We also found the single strategy of using positive airflow into a face mask ineffective, even with extremely high levels of airflow. Complete protection was only achieved reliably by the combination of physically sealing off the face from the surrounding airspace and using the air-fed system to provide an external source of air to breathe. We effectively made the clinical equivalent of a dive bell helmet. The air-fed mask is supplied by a standard dental air compressor and is simple to install for someone familiar with the technical aspects of compressors. The compressor does not rely on a filter and proves effective with cheap and easily accessible disposable items. Conclusion: Under rigorous testing conditions, the developed air-fed mask system with a sealed hood on low flow performed better than hospital-issued PPE against high-speed dental aerosol protection. The developed system protects the operators from the air of the room contaminated with aerosol and brings in safe air from the outside for them to breathe.


2021 ◽  
Vol 9 (2) ◽  
pp. 9-19
Author(s):  
Mohammed Ghalib Al-Azawy

This article describes the numerical investigation of blood rheology within an artery that includes two narrowing areas via Computational Fluid Dynamics (CFD). Elliptic blending Reynolds stress model and two models of viscosity have been used in this investigation utilizing STAR-CCM+ 2021.2.1. The test model includes two elliptical stenosis with a 2mm distance between them, and the area of stenosis is 75%. Results of normalized axial velocity, turbulent kinetic energy (TKE) and turbulent viscosity ratio (TVR) were evaluated before, through and after the stenosis in order to predict and avoid the real problems that occur from changing the area of the artery. Furthermore, Fractional flow reserve (FFR) was employed to assess the level of risk of stenosis through the artery, which depends on pressure measurements. Corresponding to the author's observation, it was found that the recirculation regions in the area between the stenosis are larger than the area after the stenosis. Moreover, the results of TKE and TVR are almost identical through and downstream of the stenosis, whereas the TKE is slightly higher with the Carreau model than with the Newtonian flow at the upstream and through the first stenosis.


2021 ◽  
Vol 4 (4) ◽  
Author(s):  
Kadriye Uçar ◽  
◽  
Havva A. Karabulut ◽  
Yunus Yılmaz ◽  
Ahmet S. Uçar

It is extremely important to provide sex education to individuals with intellectual disabilities because they do not know where, when, and in which situations their sexual behavior is appropriate or not, and because they cannot control their sexuality. This study aimed to examine the effect of the Sex Education Program for Families of Adults with Intellectual Disabilities (ZACEP) on the knowledge level of families of adults with intellectual disabilities and their attitudes towards their children’s sexual development and sex education. The research adopted a single group pre-test and post-test model, one of the experimental research models. The sample consisted of nine mothers. The effectiveness data of the study were collected through the Parental Sex Education Attitude Scale. SPSS packet program was used for data analysis. The pretest and posttest items were first analyzed with descriptive statistics, then frequency, percentage, and maximum-minimum values were calculated. The t-test analysis for dependent samples is required to compare the pretest and posttest scores of a single group. However, due to the number of participants (N=9), the Wilcoxon Signed Rank Test, which is the nonparametric equivalent of t-test, was used. Research findings showed that the ZACEP did not affect the mothers' attitudes towards the sexuality of adults with intellectual disabilities. Besides, the ZACEP did not affect parents' attitudes towards sexuality at item level.


2021 ◽  
Vol 12 (05) ◽  
pp. 352-367
Author(s):  
Edenyce Krismartini Eduard ◽  
Widiatuti Widiastuti ◽  
Johansyah Lubis

Abstract. The aim of this study is to produce a game-based cricket bowling skill exercise model by testing the effectiveness of improving bowling skills in children aged 12-15 years. The method used in this study is research and development from Borg and Gall by using 10 stages. The research subjects for group trials and effectiveness are (1) small group trials of 16 children at SD Negeri 15 Pagi Pondok Bambu, (2) large group trials of 25 children at SMP Negeri 2 Kebakkramat, and (3) tests effectiveness of 40 children at Karanganyar Cricket Club.The data collection technique used is the result of expert validation and effectiveness test through an assessment instrument with t-test statistical data analysis. The validity test used by expert justification test, presented 3 experts consisting of: 1 games lecturer, 1 cricket lecturer, and 1 national cricket coach. The final model is produced 15 bowling cricket skill exercise models. The effectiveness test model uses the skills results of cricket bowling. The improvement of bowling cricket skills results showed a significance of t count=14,512, db=39 and p-value=0.00<0.05, which means that there is a significant difference between before and after being given the training model treatment, the pre-test average was 2.23 smaller than the post-test average is 4.47. It can be concluded that the game-based cricket bowling skill training model developed is quite effective for improving bowling skills in children aged 12-15 years.


2021 ◽  
Vol 9 (2) ◽  
pp. 9-19
Author(s):  
Mohammed G. Al-Azawy

AbstractThis article describes the numerical investigation of blood rheology within an artery that includes two narrowing areas via Computational Fluid Dynamics (CFD) to offer guidance to the community, especially surgeons, and help them to avoid the risk of stenosis. Elliptic blending Reynolds stress model and two models of viscosity have been used in this investigation utilizing STAR-CCM+ 2021.2.1. The test model includes two elliptical stenosis with a 2mm distance between them, and the area of stenosis is 75%. Results of normalized axial velocity, turbulent kinetic energy (TKE) and turbulent viscosity ratio (TVR) were evaluated before, through and after the stenosis in order to predict and avoid the real problems that occur from changing the area of the artery. Furthermore, Fractional flow reserve (FFR) was employed to assess the level of risk of stenosis through the artery, which depends on pressure measurements. Corresponding to the author's observation, it was found that the recirculation regions in the area between the stenosis are larger than the area after the stenosis. Moreover, the results of TKE and TVR are almost identical through and downstream of the stenosis, whereas the TKE is slightly higher with the Carreau model (arrive to 0.54 J/kg) than with the Newtonian flow (arrive to o.47 J/kg) at the upstream and through the first stenosis.


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