scholarly journals Study on rheological properties of polymer grouting materials with different expansion rates

2020 ◽  
Vol 165 ◽  
pp. 05019
Author(s):  
Zheng Zhigang ◽  
Liu Tao ◽  
Hong Shaoyou ◽  
Huang Zhi ◽  
Wu Yintan ◽  
...  
Keyword(s):  
Expansion Ratio ◽  
Expansion Rate ◽  
Time Varying ◽  
Rotational Viscometer ◽  
Factors Affecting ◽  
Reactive Polymer ◽  
Expansion Force ◽  
Polymer Slurry ◽  
Grouting Materials ◽  
Varying Viscosity

Non-water reactive polymer grouting technology is an important means to control water-induced engineering disaster emergency rescue. However, the time-varying viscosity of polymer slurry and the expansion force of slurry reaction are the main factors affecting the grouting treatment effect. Therefore, it is necessary to study the time-varying viscosity of polymer slurry and the expansion force of slurry reaction. Firstly, the expansion rate of polymer slurry with different expansion ratio is tested and checked by the self-made expansion rate measuring cylinder. Then, the reaction expansion force and viscosity of polymer slurry with different expansion ratio are tested and studied by the expansion force testing device and NDJ-5T digital rotational viscometer. The results show that the expansion rate of polymer slurry used in this paper is basically the same as the factory instructions At the same time, the viscosity of polymer slurry increases exponentially with time, and the curve is steeper, that is to say, the viscosity increases rapidly with time.

scholarly journals Estimation of a Time-varying Apparent Infection Rate from Plant Disease Progress Curves: A Particle Filter Approach

2019 ◽  
Author(s):  
Kaique dos S Alves ◽  
Willian B Moraes ◽  
Wellington B da Silva ◽  
Emerson M Del Ponte
Keyword(s):  
Particle Filter ◽  
Infection Rate ◽  
Plant Disease ◽  
Host Susceptibility ◽  
Time Varying ◽  
Factors Affecting ◽  
Initial Inoculum ◽  
Disease Progress ◽  
Progress Curve ◽  
Apparent Infection Rate

AbstractThe parameters of the simplest (two-parameter) epidemiological models that best fit plant disease progress curve (DPC) data are the surrogate for initial inoculum (y0) and the (constant) apparent infection rate (r), both being useful for understanding, predicting and comparing epidemics. The assumption thatris constant is not reasonable and fluctuations are expected due to systematic changes in factors affecting infection (e.g. weather favorability, host susceptibility, etc.), thus leading to a time-varyingr, orr(t). An arrangement of these models (e.g. logistic, monomolecular, etc.) can be used to obtainrbetween two time points, given the disease (y) data are available. We evaluated a data assimilation technique, Particle Filter (PF), as an alternative method for estimatingr(t). Synthetic DPC data for a hypothetical polycyclic epidemics were simulated using the logistic differential equation for scenarios that combined five patterns ofr(t) (constant, increasing, decreasing, random or sinusoidal); five increasing time assessment interval (Δt= 1, 3, 5, 7 or 9 time units - t.u.); and two levels of noise (α = 0.1 or 0.25) assigned toy(t). The analyses of 50 simulated 60-t.u. DPCs showed that the errors of PF-derivedwere lower (RMSE < 0.05) for Δt< 5 t.u. and least affected by the presence of noise in the measure compared with the logit-derivedr(t). The ability to more accurately estimater(t) using the novel method may be useful to increase knowledge of field epidemics and identify within-season drivers that may explainr(t) behaviour.

scholarly journals Numerical Study on Identification of Time Varying Parameters of Vibration Systems

1997 ◽  
Vol 4 (1) ◽  
pp. 69-76
Author(s):  
Yanchun Liang ◽  
Qiang Zhen ◽  
Zaishen Wang
Keyword(s):  
Linear Model ◽  
Nonlinear Term ◽  
Numerical Study ◽  
Time Varying ◽  
Linear Vibration ◽  
Factors Affecting ◽  
Varying Parameters ◽  
Time Varying Parameters ◽  
On Line ◽  
Time Invariant

An on-line least squares algorithm has previously been successfully applied to linear vibration systems in order to identify time varying parameters. In this article the limitations of the approach and the factors affecting the identification are further examined. The existence of the nonlinear term is determined by means of the time varying characteristics of the estimated linear parameters using the linear model and the data from a time invariant nonlinear system. The identification of the time varying linear parameters is also examined in accordance with the linear model by using the data with nonlinear elements.

Performance Optimization of Cement-Fly Ash Grouting Material Based on Response Surface Methodology

2021 ◽  
Vol 1036 ◽  
pp. 337-344
Author(s):  
Lin Lin Wang ◽  
Xiang Bin Xu ◽  
Qing Song Zhang ◽  
Shi Yi Li
Keyword(s):  
Response Surface Methodology ◽  
Fly Ash ◽  
Response Surface ◽  
Performance Optimization ◽  
Reducing Agent ◽  
Sand Fly ◽  
Hydration Reaction ◽  
Factors Affecting ◽  
And Performance ◽  
Grouting Materials

Filling grouting is effective to control the overlying strata movement and surface subsidence in mining and tunnel engineering.Grouting material is used in grouting reinforcement projects. In this experiment,based on the mechanical properties of grouting materials, Expert Design and response surface methodology (RSM) is used to optimize the mix proportion of grout materials. The sand-fly ash ratio ,water reducing agent addition are researched as variables, and the 3D response surface is established between the factors and the performance indicators. Microstructure explains the mechanism of factors affecting performance indicators.The results show the relationship between factors and performance can be well fitted by RSM.The order of significance on compressive strength and solidification ratio is sand-fly ash ratio＞water reducing agent addition and the order of significant on viscosity is water reducing agent addition＞sand-fly ash ratio.Response surface methodology accurately describes the functional relationship between the target value and the design variables.Microstructure shows hydration reaction and the secondary hydration reaction of fly ash will be carried out after cement-fly ash mixed, and the addition of fly ash is especially important for grout material properties.

scholarly journals Product Life Cycle and Time Varying Advertising Elasticity in Port Harcourt, Rivers State

2021 ◽  
Vol 04 (08) ◽  
Author(s):  
Ambille, Beauty Eric ◽  
Keyword(s):  
Life Cycle ◽  
Product Life Cycle ◽  
Cumulative Effect ◽  
Sales Representative ◽  
Time Varying ◽  
Product Life ◽  
Factors Affecting ◽  
Port Harcourt ◽  
Rival Firms ◽  
Rivers State

The research study examines product life cycle and time-varying advertising elastics in Port Harcourt, Rivers State. The population of the study consisted of 10 Television dealers, 10 Food and Beverages Distributors, 5 Tobacco Distributors, 10 Detergent Distributors, 10 Foam Mattress and Bedding Dealers and Suppliers registered with the Rivers State Chamber of Commerce. The sample size of the study consisted of 40 firms and a total of 120 respondents made up of owners, senior managers, sales representative and marketing executives in the frame of three (3) respondents from each firm were surveyed through the administration of questionnaire. The instrument for data collection contains 4 questions for the independent variable and 20 questions for dependent variables. Product life cycle was measured with time varying advertising elasticities, total scales of a product brand; advertising by rival firms, cumulative effect of past advertisement of product brand and advertising elasticity affected by other factors affecting demand for a product brand. The Cronbach Alpha was calculated to confirm the reliability of the study construct. The reliability coefficient obtained was 0.82 and the data generated were analyzed using mean and standard deviation scores. The researcher used Person Product Moment Correlation to test the stated hypotheses. Findings reveals that product life cycle is significantly associated with time varying advertising elasticities of product brand. The study conclude that to fully adopt product life cycle and the varying advertising elasticities dimension as key strategies for business cycle growth and continued survival. The researcher thus recommended that marketing and sales managers should utilize the huge benefit to advertising elasticity to campaign effectively in generating new sales in line with the product life cycle of a product life/brand, reduce product cost to prevent potential competitors, ensure the product should be reformulated and remodeled to suit the consumers’ preferences.

scholarly journals Experimental and Numerical Analysis of Expanded Pipe using Rigid Conical Shape

2018 ◽  
Vol 24 (8) ◽  
pp. 106
Author(s):  
Ahmed Ibrahim Razooqi
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Numerical Analysis ◽  
Expansion Ratio ◽  
Large Plastic Deformation ◽  
Expansion Process ◽  
Finite Element Software ◽  
Conical Shape ◽  
Expansion Force ◽  
Good Agreement

The experimental and numerical analysis was performed on pipes suffering large plastic deformation through expanding them using rigid conical shaped mandrels, with three different cone angles (15◦, 25◦, 35◦) and diameters (15, 17, 20) mm. The experimental test for the strain results investigated the expanded areas. A numerical solution of the pipes expansion process was also investigated using the commercial finite element software ANSYS. The strains were measured for each case experimentally by stamping the mesh on the pipe after expanding, then compared with Ansys results. No cracks were generated during the process with the selected angles. It can be concluded that the strain decreased with greater angles of conical shape and an increase in expansion ratio results in an increase of expansion force and a decrease in the pipe thickness and length resulting in pipe thinning and shortening. Good agreement is evident between experimental and ANSYS results within discrepancy (16.90017%) in the X direction and (27.68698%) in the Y direction. Also, the stress distribution is investigated and it can be concluded that the case of Diameter (Do cone) = 35mm and (A) = α = 15° is the optimum.  

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