Model Test Study On Mechanical Characteristics Of Spherical Joints In Multi‐Point Support Swivel System,
2023
China Railway 11th Bureau Group First Engineering Co., Ltd., Xiangyang, Hubei 441000, China
Model Test Study On Mechanical Characteristics Of Spherical Joints In Multi‐Point Support Swivel System, Zeng Lifei
Journal of China & Foreign Highway
As a critical load-bearing component in bridge swivel systems, the mechanical behavior of spherical joints is essential for the safety of bridge swiveling operations. This study focuses on the spherical joints of a multi-point support swivel system for the bridge over the Xiangyang North Marshalling Yard. Model tests were conducted to analyze the effects of the number of supporting legs, swivel speed, track smoothness, and wind load on the stress of spherical joints. The stress variation patterns of spherical joints under different working conditions were investigated. The results show that increasing the number of supporting legs improves the uniformity of …
Selection Of Phase Change Materials For Asphalt Pavement Based On Molecular Dynamics Simulation,
2023
China Highway and Transportation Society, Beijing 100011, China
Selection Of Phase Change Materials For Asphalt Pavement Based On Molecular Dynamics Simulation, Liu Fujun, Tian Xin, Liang Meichen, Guo Meng
Journal of China & Foreign Highway
Phase change materials (PCMs) have significant application potential in temperature regulation for asphalt pavements. To select suitable PCMs for road applications, this paper utilizes molecular dynamics simulation to analyze the molecular behaviors of lauric acid and polyethylene glycol (PEG). Experimental studies were conducted to validate the simulation results. The results show that molecular dynamics simulation provides an efficient and convenient method for comparing the performance of PCMs. PEG outperforms lauric acid in terms of molecular density, cohesive energy density, solubility parameters, and thermal conductivity, making it more suitable as a phase change material for asphalt pavements.
Study On Alkali Excitation Mechanism Of Large Dosage Slag Fine Powder,
2023
Department of Civil Engineering, Henan Technical College of Construction, Zhengzhou, Henan 450064, China
Study On Alkali Excitation Mechanism Of Large Dosage Slag Fine Powder, Mei Yang
Journal of China & Foreign Highway
To reveal the alkali excitation mechanism of high-dosage slag, this paper combines a three-factor, three-level orthogonal design with macro- and micro-performance tests and microstructure analysis. The effects of different activators, including Ca(OH)2, Na2SiO3, Na2SO4, and CaSO4, in single and dual combinations on the initial and final setting times, pore solution pH, and strength of concrete were explored. The results show that the impact on the strength of hardened paste of composite cementitious materials is ranked as: activator type > dosage > dual-mix ratio. The optimal dual-mix dosage is 4%, with the best combination being Ca(OH)2 and Na2SiO3 at a ratio of 5:1. …
Study On Microstructure Of Asphalt Modified By Oil‐Coal Blend,
2023
Yulin Highway Bureau, Yulin, Shaanxi 710009, China
Study On Microstructure Of Asphalt Modified By Oil‐Coal Blend, Guo Pengfei, Zhou Xinfeng
Journal of China & Foreign Highway
To investigate the microstructure and modification mechanism of asphalt modified with oil-coal blend, SK-90# asphalt was mixed with 5%, 10%, 15%, 20%, and 25% (external blending method) oil-coal blend to produce modified asphalt. The performance and microstructural changes of the modified asphalt were analyzed using contact angle testing, infrared spectroscopy, cross-sectional SEM, and X-ray photoelectron spectroscopy. The results show that the oil-coal blend exhibits good compatibility with asphalt. During the modification process, esterification reactions occurred, resulting in a decrease in hydroxyl-containing aromatic compounds and an increase in carbonyl-containing aromatic compounds. Macroscopically, the oil-coal blend-modified asphalt demonstrated excellent high-temperature performance.
Analysis Of Expressway Routine Maintenance Performance Management Based On Dea,
2023
Highway School, Chang’an University, Xi’an, Shaanxi 710064, China; Xi’an Municipal Design and Research Institute Co., Ltd., Xi’an, Shaanxi 710068, China
Analysis Of Expressway Routine Maintenance Performance Management Based On Dea, Li Yuhuan, Shi Xiaoli, Gao Nan
Journal of China & Foreign Highway
To allocate maintenance resources efficiently and improve management levels, this paper examines the maintenance performance and improvement strategies of routine maintenance projects for 23 expressways in Shaanxi Province using 2018 operational maintenance data and data envelopment analysis. The results show that for some inefficient subsidiaries, traditional radial- and slack-based performance improvement methods are challenging and impractical in the short term. Therefore, a scenario-dependent model-based long-term incremental improvement strategy is proposed. By leveraging relative improvement values, this strategy enables phased improvements for inefficient subsidiaries. It provides a feasible approach for subsidiaries to set lower short-term performance improvement targets while achieving gradual …
Movie Recommender System Using Matrix Factorization,
2023
University of Central Florida
Movie Recommender System Using Matrix Factorization, Roland Fiagbe
Data Science and Data Mining
Recommendation systems are a popular and beneficial field that can help people make informed decisions automatically. This technique assists users in selecting relevant information from an overwhelming amount of available data. When it comes to movie recommendations, two common methods are collaborative filtering, which compares similarities between users, and content-based filtering, which takes a user’s specific preferences into account. However, our study focuses on the collaborative filtering approach, specifically matrix factorization. Various similarity metrics are used to identify user similarities for recommendation purposes. Our project aims to predict movie ratings for unwatched movies using the MovieLens rating dataset. We developed …
An Analysis Of All-Cause Mortality On Patients With Sickle Cell Disease And Kidney Disease Using Propensity Score Matching,
2023
Stephen F. Austin State University
An Analysis Of All-Cause Mortality On Patients With Sickle Cell Disease And Kidney Disease Using Propensity Score Matching, Adam Garrison
Electronic Theses and Dissertations
In this work, we provide an overview of the Cox proportional hazards model for time to event or survival analysis and the notion of propensity score matching to deal with confounding factors. A full analysis is reported in Chapter 2 concerning mortality for in-center dialysis patients with sickle cell disease to demonstrate the application of a general analysis strategy that has some logistical benefits over more traditional approaches to accounting for confounding variables. We also provide some insight and discussions on the challenges and future research questions that will emerge when trying to implement this strategy as a monitoring tool …
Brief Review: Low Frequency Event Charts (G-Charts) In Healthcare,
2023
Rowan University
Brief Review: Low Frequency Event Charts (G-Charts) In Healthcare, James Espinosa, David Ho, Alan Lucerna, Henry Schuitema
Rowan-Virtua Research Day
The ability to determine if a change in a system is actually an improvement—or worsening in function—is one of the essential desiderata of quality improvement efforts. There are many ways to look at the issue. A special problem occurs when the event being studied is low frequency by nature. By way of example, patient falls in a given hospital or division of a hospital may occur in a way that is low frequency—yet each event is important. Process engineering has developed an approach to low frequency events. Part of this approach may involve specialized charts that look at the “time-between-events”—as …
A Monte Carlo Analysis Of Nonprobability Sampling & Post Hoc Corrections,
2023
Western Kentucky University
A Monte Carlo Analysis Of Nonprobability Sampling & Post Hoc Corrections, Julia Hong
Masters Theses & Specialist Projects
Nonprobability samples are often used in place of probability samples because the former are less trouble and less expensive. Unfortunately, it is difficult to determine how well a sample represents population parameters when using nonprobability samples. Researchers attempt to mitigate the disadvantages of nonprobability sampling by performing post hoc corrections, but this adjustment may not successfully undo the effects of nonprobability sampling. To examine these effects, a Monte Carlo simulation was conducted to create a pseudo-population from which samples were drawn. Forty-one conditions were replicated 10,000 times each, with each sample consisting of 100 observations. A post-stratification adjustment was made …
Distance Correlation Based Feature Selection In Random Forest,
2023
California State University - San Bernardino
Distance Correlation Based Feature Selection In Random Forest, Jose Munoz-Lopez
Electronic Theses, Projects, and Dissertations
The Pearson correlation coefficient is a commonly used measure of correlation, but it has limitations as it only measures the linear relationship between two numerical variables. In 2007, Szekely et al. introduced the distance correlation, which measures all types of dependencies between random vectors X and Y in arbitrary dimensions, not just the linear ones. In this thesis, we propose a filter method that utilizes distance correlation as a criterion for feature selection in Random Forest regression. We conduct extensive simulation studies to evaluate its performance compared to existing methods under various data settings, in terms of the prediction mean …
Employee Attrition: Analyzing Factors Influencing Job Satisfaction Of Ibm Data Scientists,
2023
Kennesaw State University
Employee Attrition: Analyzing Factors Influencing Job Satisfaction Of Ibm Data Scientists, Graham Nash
Symposium of Student Scholars
Employee attrition is a relevant issue that every business employer must consider when gauging the effectiveness of their employees. Whether or not an employee chooses to leave their job can come from a multitude of factors. As a result, employers need to develop methods in which they can measure attrition by calculating the several qualities of their employees. Factors like their age, years with the company, which department they work in, their level of education, their job role, and even their marital status are all considered by employers to assist in predicting employee attrition. This project will be analyzing a …
Length Bias Estimation Of Small Businesses Lifetime,
2023
University of Richmond
Length Bias Estimation Of Small Businesses Lifetime, Simeng Li
Honors Theses
Small businesses, particularly restaurants, play a crucial role in the economy by generating employment opportunities, boosting tourism, and contributing to the local economy. However, accurately estimating their lifetimes can be challenging due to the presence of length bias, which occurs when the likelihood of sampling any particular restaurant's closure is influenced by its duration in operation. To address the issue, this study conducts goodness-of-fit tests on exponential/gamma family distributions and employs the Kaplan-Meier method to more accurately estimate the average lifetime of restaurants in Carytown. By providing insights into the challenges of estimating the lifetimes of small businesses, this study …
Prevalence Of Sars-Cov-2 Antibodies In Liberty University Student Population,
2023
Liberty University
Prevalence Of Sars-Cov-2 Antibodies In Liberty University Student Population, Emily Bonus
Senior Honors Theses
In 2020, the virus SARS-CoV-2 gained attention as it spread around the world. Its antibodies are poorly understood, and little research focuses on those with few COVID-19 complications yet large numbers of close contacts: university students. This longitudinal study recorded SARS-CoV-2 antibody presence in 107 undergraduate Liberty University students twice during early 2021. After extensive data cleaning and the application of various statistical tests and ANOVAs, the data seems to show that in the case of COVID-19 infections, SARS-CoV-2 IgM antibodies are immediately produced, and then IgG antibodies follow later. However, the COVID-19 vaccine causes the production of both IgM …
Influence Diagnostics For Generalized Estimating Equations Applied To Correlated Categorical Data,
2023
Southern Methodist University
Influence Diagnostics For Generalized Estimating Equations Applied To Correlated Categorical Data, Louis Vazquez
Statistical Science Theses and Dissertations
Influence diagnostics in regression analysis allow analysts to identify observations that have a strong influence on model fitted probabilities and parameter estimates. The most common influence diagnostics, such as Cook’s Distance for linear regression, are based on a deletion approach where the results of a model with and without observations of interest are compared. Here, deletion-based influence diagnostics are proposed for generalized estimating equations (GEE) for correlated, or clustered, nominal multinomial responses. The proposed influence diagnostics focus on GEEs with the baseline-category logit link function and a local odds ratio parameterization of the association structure. Formulas for both observation- and …
That’S My Deity: An Examination Of Online Lokean Cultures Through Log-Linear Modeling,
2023
University of South Carolina - Columbia
That’S My Deity: An Examination Of Online Lokean Cultures Through Log-Linear Modeling, Mary Bernstein
Senior Theses
A rise in online religious communities and the growth of so-called ‘Old World’ religions are reflected in the internet’s subcultures of Neopaganism, a growing religious movement that has been documented in America since the 1960s. The religions under this umbrella movement vary drastically and include belief systems such as Wicca, Druidry, and deity worship. Belief systems under this movement lack the traditional hierarchy found in structured religion and lack a singular sacred text. As such, believers usually find and support one another not through a physical sacred place of meeting, but through an online community that acts as sacred space. …
Study On Thermal Property Of Fast Growing Grass Fiber And Its Asphalt Mortar,
2023
Southern Green Road Research Institute, Central South University of Forestry & Technology, Changsha, Hunan 410004, China
Study On Thermal Property Of Fast Growing Grass Fiber And Its Asphalt Mortar, Xia Chaoming, Jiang Kang, Wu Chaofan, Liu Kefei
Journal of China & Foreign Highway
In order to investigate the thermal properties of fast-growing grass fiber and its asphalt mortar, the physical properties and thermal properties of bamboo fiber, reed fiber, and its asphalt mortar were tested and compared with those of lignin fiber and its asphalt mortar by physical property test, thermal weight loss test, and differential scanning calorimetry test. The results show that the addition of plant fiber can effectively improve the high temperature performance of asphalt, but it has a slight inhibition effect on the low temperature performance of asphalt. The quality loss of plant fiber in different temperature ranges is the …
Influence Of Curvature Radius On Mechanical Properties Of Small And Medium Span Continuous Rigid Frame Bridge During Construction Stages,
2023
Pengzhou City Construction Investment Group Co., Ltd., Chengdu, Sichuan 611930, China
Influence Of Curvature Radius On Mechanical Properties Of Small And Medium Span Continuous Rigid Frame Bridge During Construction Stages, Xie Yangfu, Ye Yuansheng, Gui Shuirong, Yang Yu
Journal of China & Foreign Highway
In order to study the mechanical properties and the influence of curvature radius on the mechanical properties of curved rigid frame bridge constructed by span-by-span assembly method, this paper took the continuous rigid frame bridge with a two-box standard section (35 + 35 + 35) m of Hongdu Overpass in Nanchang City as the engineering background. By changing the curvature radius, the influence of curvature radius on the mechanical properties of small- and medium-span continuous rigid frame bridges constructed by span-by-span assembly method during construction was studied. The results show that the mechanical properties such as the main beam stress, …
Study On Pavement Performance Of Waterborne Epoxy Emulsified Asphalt And Its Application In Micro‐Surface,
2023
Hubei Liantou Exian Investment Co., Ltd., Ezhou, Hubei 436000, China
Study On Pavement Performance Of Waterborne Epoxy Emulsified Asphalt And Its Application In Micro‐Surface, Jiang Hai, Liu Dachang
Journal of China & Foreign Highway
In order to improve the pavement performance at micro-surface, waterborne epoxy resin was used to modify the emulsified asphalt, and the compatibility, microstructure, mechanical properties, rheological properties, and pavement performance of mixtures of the modified emulsified asphalt were studied. The storage stability test shows that the epoxy emulsion has good compatibility with emulsified asphalt. With the increase in waterborne epoxy resin content, the modified emulsified asphalt tends to form an epoxy resin-dominated skeleton structure. At the same time, with the increase in waterborne epoxy resin content, the adhesion and mechanical properties of emulsified asphalt and aggregate are significantly improved. At …
Study On The Effect Of Quicklime On The Properties Of Cold Mix Asphalt,
2023
Jiangxi Communications Investment Group Co., Ltd., Nanchang, Jiangxi 330025, China;
Study On The Effect Of Quicklime On The Properties Of Cold Mix Asphalt, Liu Tao, Yi Ming, Song Tao
Journal of China & Foreign Highway
The low initial strength of cold mixed asphalt mixture leads to the delay of traffic opening time, and the large void ratio leads to poor water stability and other problems, which seriously hinder the development of cold mixed environment-friendly construction mode. In this paper, based on the principle that the heat of quicklime in the presence of water promotes the rapid loss of water in the cold mixed mixture, the mixing test and cohesion test of the MS-3 slurry cold mixed asphalt mixture with quicklime were carried out to explore the influence of quicklime on the demulsification time and cohesion. …
The Calculation Theory Of Humidity For Subgrade ：A Perspective Review,
2023
Changsha University of Science and Technology
The Calculation Theory Of Humidity For Subgrade ：A Perspective Review
Journal of China & Foreign Highway
Subgrade humidity has a significant impact on its stiffness, deformation, and other properties. The theoretical calculation method of humidity field has always been one of the key issues in road engineering as a research method to evaluate its evolution law and mechanism. This paper reviewed and summarized the control equation of subgrade humidity calculation, hydraulic characteristics of unsaturated subgrade soil, and influencing factors of humidity. It was found that there were few studies on the coupling effects of multiple fields and factors such as stress, seepage, vegetation, and atmosphere in the whole calculation method system. It is suggested to carry …
