scholarly journals Analysis of the temperature effect on the stresses and deformations of GRP panels during the grouting process when using relining technology

2021 ◽  
Vol 43 (s1) ◽  
pp. 521-531
Author(s):  
Zuzanna Fyall

Abstract The paper presents a numerical analysis of the behaviour of egg-shaped glass-reinforced plastic (GRP) panels during the grouting process when using short relining technology. The analysis was carried out for panels subjected to temperature changes. The temperature increase was caused by the heat of hydration of the grout. It was shown that temperature had a significant effect on the stresses occurring in the panels’ walls and also on their deformations. The analysis involved grout being added in a single stage and then in two stages for comparison. The distribution of stresses and deformations were examined for panels with different wall thicknesses that ranged from 12 to 20 mm. Extensive knowledge about the grouting process and the effect of temperature on the behaviour of GRP panels during the assembly stage when using short relining technology could make this non-disruptive technology more competitive with regards to the time of its implementation and its costs when compared to traditional methods.

2000 ◽  
Vol 46 (152) ◽  
pp. 7-14 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Yu Zhang

AbstractA degree-day model is used to assess the sensitivity of the mass balance of five Swiss glaciers to temperature changes. The model uses temperature data extrapolated from nearby climate stations, and is tuned by varying precipitation to make the model fit the observed distribution of mass balance with altitude. Once the model is tuned, the effect of temperature change is simulated by recalculating the mass balance with the same parameters as before, but with a temperature increase of 1°C throughout the year. The largest mass-balance changes, involving increased ablation of > 1 m w.e. a−1 °C−1, occur at the snout, with a progressively smaller increase with altitude. The area-averaged sensitivities for the five glaciers are −0.7 to −0.9 m w.e. a−1 °C−1. If annual precipitation also increased by 20% it would partly offset the effect of the 1°C higher temperatures but could not compensate for it.


Author(s):  
Natalia Kaszuba ◽  
Teresa Kasprzyk-Kucewicz ◽  
Karolina Bałamut ◽  
Tadeusz Morawiec ◽  
Agata Stanek ◽  
...  

AbstractThe main goal of this study was to find out if thermal imaging may be useful in the evaluation of two types of anaesthetic injections—with and without a vasoconstrictor. There were 20 patients (13 women and 7 men) involved in the study. The group was divided into two subgroups. Patients from the first subgroup received infiltration anaesthesia (so-called: IA) of lidocaine (2 mL) and the second group included patients, who received infiltration anaesthesia (so-called: IAN) of lidocaine with 2% noradrenaline (2 mL). The obtained results showed a significant increase in the average temperature 10 min after the injection. In the IA group, the temperature increase was nearly 1.0 °C what was 0.3 °C higher than in the IAN group. Moreover, temperature changes showed a wide plateau between 10 and 25 min after anesthesia administration. The effect of temperature rise was also observed on the contralateral cheek where there was no intervention renders by a contralateral reflex.


2020 ◽  
Author(s):  
Md Shahjalal Chowdhury

Climate change is one of the most concerning global issues and has the potential to influence every aspect of human life. Like different components of society, it can impose significant adverse impacts on pavement infrastructure. Although several research efforts have focused on studying the effects of climate change on natural and built systems, its impact on pavement performance has not been studied as extensively. The primary objectives of this thesis research was to quantify the effect of temperature changes on flexible pavement response and performance prediction using the AASHTOWare Pavement ME Design (PMED), and quantify the effects of Local Calibration Factors (LCFs) used by different state highway agencies in the United States on predicted pavement performance. Particular emphasis was given to LCF values used by the Idaho Transportation Department. The climatic data, as well as LCFs corresponding to several different states, were used to identify how different LCF values affect pavement performance prediction. The effects of atmospheric temperature changes on pavement temperature and Asphalt Concrete (AC) layer modulus were studied by analyzing the intermediate files generated by PMED. Finally, the impact of temperature change on AC dynamic modulus (E*) was also analyzed to link the PMED-predicted distresses with asphalt mix properties. Historical climatic data was obtained from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) database. Projected data considered to simulate the temperature changes in the future were generated by adopting two different approaches: (1) Manual alteration of historical temperature distribution data to represent scenarios with increased mean and standard deviation values; and (2) Use of temperature data projected by established Global Climate Models (GCM). All different climatic scenarios were used in PMED along with a standard pavement section, and the distresses predicted over the design life of the pavement were compared. Simulation results showed consistent increase in Total Pavement rutting and AC rutting with increasing air temperatures. The effect of temperature increase on AC thermal cracking predicted by PMED demonstrated inconsistent trends. In contrast, the projected temperature increase had no significant effect on bottom-up fatigue cracking for the chosen study locations. It was found that the impact of changed air temperatures can be different for pavement sections constructed in different geographic locations. Moreover, the analysis confirmed that the Local Calibration Factors (LCFs) established by different state highway agencies played a major role in governing the effect of future temperature increase on predicted pavement performance. Through an extensive study of the LCFs used in the states of Idaho, Colorado, and Michigan, it was observed that the LCFs in Idaho did not adequately reflect the effects of future temperature changes on predicted pavement performance. Findings from this study emphasize the importance of considering non-stationary climate conditions likely to occur in the future during the process of pavement design. Moreover, this study also highlighted different aspects of the LCFs that play a significant role in capturing the effects of climatic factors on pavement performance predicted by PMED. Based on the findings, it is believed that further fine-tuning of the LCFs used in Idaho may be needed.


2018 ◽  
Vol 77 (6) ◽  
pp. 375-381
Author(s):  
K. M. Popov

Abstract. Influence of air temperature on the consumption of fuel and energy resources (FER) on train traction is due to a number of physical laws. The extent of this effect is specified in the Rules for Traction Settlement (RTS). At the same time, when rationing FER consumption for train traction, a specialized methodical base is used, which involves a different approach to accounting for the effect of temperature on FER consumption for train traction. At the same time in different documents of this base, the effects of low temperature on the absolute and specific consumption of fuel and energy resources on train traction are taken into account in a different way, which is due to the lack of consensus among specialists on the way this factor is taken into account. Specialists of JSC “VNIIZhT” carried out an analysis of a significant amount of driver’s routes data, results of which showed that the dependence of the specific flow rate on temperature, on the basis of which the corresponding influence coefficient is determined, needs to be periodically updated. In addition, when technically standardizing the consumption of fuel and energy resources (for the locomotive crew work site), the temperature effect coefficients need to be calculated for a specific work area and direction of motion on it, while using the average network coefficient values will lead to errors. When calculating additional flow of fuel and energy from the effect of temperature for electric multiple units (EMU), the equations of regression dependencies should be used, obtained by statistical processing of data on temperature changes and specific consumption of fuel and energy resources for EMU and determined for each series of EMU when working on a particular suburban area.


Author(s):  
Yiqun Huang ◽  
Pawan Singh Takhar ◽  
Juming Tang ◽  
Barry G Swanson

Rheological behaviors of high acyl (HA) gellan are not well understood partially because of its relatively late commercialization compared to low acyl gellan. The objective of this study was to investigate the effect of temperature (5-30 °C), calcium (0, 1 and 10 mM) and gellan concentrations (0.0044-0.1000% w/v) on the flow behaviors of high acyl gellan aqueous solutions using rheological tests. Gellan solutions with 0 or 1 mM added Ca++ exhibited shear thinning behavior at gellan concentrations above 0.0125%. The influence of temperature on apparent viscosity (shear rate, 100 s-1) of gellan solutions can be described with an Arrhenius relationship. The apparent viscosity of gellan solution at low concentrations was more sensitive to temperature changes. The addition of Ca++ led to a decrease in flow resistance for a dilute gellan solution (<0.0125%), but an increased resistance for a relatively concentrated gellan solution (>0.0125%).


2020 ◽  
Vol 15 ◽  
pp. 65
Author(s):  
Salisu M. Garba ◽  
Usman A. Danbaba

In this study, a non-autonomous (temperature dependent) and autonomous (temperature independent) models for the transmission dynamics of malaria in a population are designed and rigorously analysed. The models are used to assess the impact of temperature changes on various control strategies. The autonomous model is shown to exhibit the phenomenon of backward bifurcation, where an asymptotically-stable disease-free equilibrium (DFE) co-exists with an asymptotically-stable endemic equilibrium when the associated reproduction number is less than unity. This phenomenon is shown to arise due to the presence of imperfect vaccines and disease-induced mortality rate. Threshold quantities (such as the basic offspring number, vaccination and host type reproduction numbers) and their interpretations for the models are presented. Conditions for local asymptotic stability of the disease-free solutions are computed. Sensitivity analysis using temperature data obtained from Kwazulu Natal Province of South Africa [K. Okuneye and A.B. Gumel. Mathematical Biosciences 287 (2017) 72–92] is used to assess the parameters that have the most influence on malaria transmission. The effect of various control strategies (bed nets, adulticides and vaccination) were assessed via numerical simulations.


1999 ◽  
Vol 56 (8) ◽  
pp. 1370-1375
Author(s):  
Even H Jørgensen ◽  
Johannes Wolkers

In this study, the time-dependent P450 response to oral benzo[a]pyrene exposure at 1 and 10°C was investigated in winter- and summer-acclimated Arctic char (Salvelinus alpinus). In both seasons, a strong induction of CYP1A activities and protein levels (measured only in the winter experiment) were seen at both 1 and 10°C. At 1°C, the responses were delayed and more long-lasting than at 10°C. No within-season difference between 1 and 10°C in the magnitude of the induction response was found, but due to elevated baseline CYP1A activities, the induction response was seven times lower in winter- as compared with the response in summer-acclimated Arctic char. The results show that the CYP1A enzymes of the Arctic char respond to temperature changes in a compensatory way, and they are promising with respect to the applicability of the P450 enzyme system of the Arctic char as a biomarker for monitoring polycyclic aromatic hydrocarbon contamination in high-latitude environments. More studies are needed, however, to reveal seasonal differences in the biomarker response to pollutants.


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