Analysis of Long-Term Observation of Highway Arch Bridge Oparno

2016 ◽  
Vol 249 ◽  
pp. 209-214
Author(s):  
Vojtěch Kolínský ◽  
Jan L. Vítek
Keyword(s):  
Rheological Properties ◽  
Detailed Comparison ◽  
Bridge Construction ◽  
Final State ◽  
Arch Bridge ◽  
Arch Bridges ◽  
Long Term Observation ◽  
Long Term Behavior ◽  
The Impact

The paper deals with evaluation of experimental data collected during the Oparno arch bridge construction and with subsequent analysis of the construction process and long-term behavior with regard to rheological properties of concrete. The Oparno valley bridge is composed of two separate concrete arch structures with spans of 135 metres (this is currently the second longest span of concrete arch bridge in the Czech Republic). It was built using cantilever casting technology with temporary cable-stays and auxiliary pylons. The data recorded for this study include detailed geodetic measurement of the bridge structure during construction, along with measured strains and temperatures in the arches. Most of the data was measured during the bridge construction in 2008 and 2009. Data significant for long term behavior of structure are still being collected. Verification of different concrete material models and their suitability for design of arch bridges built by free cantilevering will be a main result of the analysis. On the basis of a detailed comparison of numerical results and measured deflections, strains and temperatures, it is possible to quantify the impact of rheological properties of the material (or their individual input parameters) on the resulting structural behavior. Unlike previous research, the examined structure is made of reinforced concrete (not prestressed) and consists of compact solid section and in the final state it is mainly in compression.

scholarly journals The Implications of HIV Treatment on the HIV-Malaria Coinfection Dynamics: A Modeling Perspective

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
F. Nyabadza ◽  
B. T. Bekele ◽  
M. A. Rúa ◽  
D. M. Malonza ◽  
N. Chiduku ◽  
...  
Keyword(s):  
Hiv Treatment ◽  
Pathogen Transmission ◽  
Disease Epidemiology ◽  
Qualitative Dynamics ◽  
Potential Impact ◽  
Negative Impacts ◽  
Long Term Behavior ◽  
The Impact ◽  
Multiple Pathogens

Most hosts harbor multiple pathogens at the same time in disease epidemiology. Multiple pathogens have the potential for interaction resulting in negative impacts on host fitness or alterations in pathogen transmission dynamics. In this paper we develop a mathematical model describing the dynamics of HIV-malaria coinfection. Additionally, we extended our model to examine the role treatment (of malaria and HIV) plays in altering populations’ dynamics. Our model consists of 13 interlinked equations which allow us to explore multiple aspects of HIV-malaria transmission and treatment. We perform qualitative analysis of the model that includes positivity and boundedness of solutions. Furthermore, we evaluate the reproductive numbers corresponding to the submodels and investigate the long term behavior of the submodels. We also consider the qualitative dynamics of the full model. Sensitivity analysis is done to determine the impact of some chosen parameters on the dynamics of malaria. Finally, numerical simulations illustrate the potential impact of the treatment scenarios and confirm our analytical results.

scholarly journals Diagenetic formation of uranium-silica polymers in lake sediments over 3,300 years

2021 ◽  
Vol 118 (4) ◽  
pp. e2021844118
Author(s):  
Pierre Lefebvre ◽  
Alkiviadis Gourgiotis ◽  
Arnaud Mangeret ◽  
Pierre Sabatier ◽  
Pierre Le Pape ◽  
...  
Keyword(s):  
Contaminated Sediments ◽  
Mining Areas ◽  
Subsurface Environments ◽  
Geochemical Reactivity ◽  
High Silica ◽  
Long Term Behavior ◽  
The Impact ◽  
X Ray Absorption

The long-term fate of uranium-contaminated sediments, especially downstream former mining areas, is a widespread environmental challenge. Essential for their management is the proper understanding of uranium (U) immobilization mechanisms in reducing environments. In particular, the long-term behavior of noncrystalline U(IV) species and their possible evolution to more stable phases in subsurface conditions is poorly documented, which limits our ability to predict U long-term geochemical reactivity. Here, we report direct evidence for the evolution of U speciation over 3,300 y in naturally highly U-enriched sediments (350–760 µg ⋅ g−1 U) from Lake Nègre (Mercantour Massif, Mediterranean Alps, France) by combining U isotopic data (δ238U and (234U/238U)) with U L3-edge X-ray absorption fine structure spectroscopy. Constant isotopic ratios over the entire sediment core indicate stable U sources and accumulation modes, allowing for determination of the impact of aging on U speciation. We demonstrate that, after sediment deposition, mononuclear U(IV) species associated with organic matter transformed into authigenic polymeric U(IV)–silica species that might have partially converted to a nanocrystalline coffinite (UIVSiO4·nH2O)-like phase. This diagenetic transformation occurred in less than 700 y and is consistent with the high silica availability of sediments in which diatoms are abundant. It also yields consistency with laboratory studies that proposed the formation of colloidal polynuclear U(IV)–silica species, as precursors for coffinite formation. However, the incomplete transformation observed here only slightly reduces the potential lability of U, which could have important implications to evaluate the long-term management of U-contaminated sediments and, by extension, of U-bearing wastes in silica-rich subsurface environments.

Novel Hanger Design to Improve the Robustness of Through Arch Bridges

2011 ◽  
Vol 90-93 ◽  
pp. 862-868
Author(s):  
Qi Ming Wu ◽  
Dang Qi Yang ◽  
Fei Cui ◽  
Xiao Wei Yi ◽  
Rui Juan Jiang
Keyword(s):  
Progressive Collapse ◽  
Time History ◽  
Structural Members ◽  
New Approach ◽  
Arch Bridge ◽  
Structural Robustness ◽  
Arch Bridges ◽  
Dynamic Time ◽  
The Impact ◽  
Emergency Measures

Hangers in through arch bridges are important components since they suspend the bridge deck from the arch ribs. Local damage at a hanger may lead to progressive damage of various components in the arch bridge or even progressive collapse of the bridge. In this paper, the conventional design of double-hangers in through arch bridges is reviewed. Then a new approach to design the double-hangers is put forward. The suitability and robustness of this approach is then verified by a numerical simulation of a real through arch bridge. The impact effects induced by local hanger fracture on other structural members are simulated by dynamic time-history analyses. The new approach to design the hangers for through arch bridges is shown to improve the structural robustness. With the application of the new way put forward here, when one or more hangers are damaged to fail, the through arch bridge will not be endangered and will still maintain the overall load-bearing capacity during an appropriate length of time to allow necessary emergency measures to be taken, which illustrates the leading principle of structural robustness well.

scholarly journals The Impact of Education and Residential Environment on Long-Term Waste Management Behavior in the Context of Sustainability

2019 ◽  
Vol 11 (14) ◽  
pp. 3775 ◽  
Author(s):  
Andreea Simona Saseanu ◽  
Rodica-Manuela Gogonea ◽  
Simona Ioana Ghita ◽  
Radu Şerban Zaharia
Keyword(s):  
Rural Areas ◽  
Academic Staff ◽  
Demographic Factors ◽  
Education Level ◽  
Waste Reduction ◽  
Long Term Effect ◽  
Long Term Behavior ◽  
The Impact ◽  
Cointegration Relationship

Currently, the problem of waste reduction is a permanent concern for all countries of the world, given the need to ensure the sustainability development. In this context, the research aims to highlight the impact of education and demographic factors by residence areas on the long-term behavior of the amount of waste generated in 29 European countries during 2013–2017. The study is based on statistical and econometric modeling aimed at identifying, testing and analyzing the existence of long-term correlation between the amount of waste per capita recorded in each country and four factors of influence considered significant for waste reduction: Pupils and students by education level and Classroom teachers and academic staff by education level, representing exogenous variables which quantify the educational outcomes, as well as The population by degree of urbanization (cities, rural areas), as demographic factors. As a result of an analysis based on correlation and regression method, a cointegration relationship between the analyzed variables was identified. Considering the amount of waste as an important component of the environmental pressure, the obtained results show the significant long-term effect that education and the demographic factor can have on its long-lasting behavior, as well as the ways through which these factors can act to strengthen sustainability.

scholarly journals Analysis on Construction Technology of Reinforced Concrete Tied Arch Bridge

2021 ◽  
Vol 5 (6) ◽  
pp. 67-71
Author(s):  
Zhongyu Wang
Keyword(s):  
Reinforced Concrete ◽  
Cost Savings ◽  
Construction Cost ◽  
Construction Technology ◽  
Bridge Construction ◽  
Construction Quality ◽  
Arch Bridge ◽  
Subsequent Application ◽  
Arch Bridges ◽  
Tied Arch Bridge

Bridge construction has received a lot of attention as transportation continues to improve. Reinforced concrete linked arch bridges are a common bridge style in today’s bridge construction. This type of bridge not only has a basic and generous shape, but it is also incredibly easy to construct, resulting in significant material and construction cost savings. This article analyzes the construction technology of a reinforced concrete linked arch bridge in order to achieve good construction and application. It is hoped that this analysis can provide a scientific reference for the guarantee of the construction quality and subsequent application effect of this kind of bridge.

Sensitivity Analysis on Dynamic Properties of Large Span Concrete-Filled Steel Tube Arch Bridge

2012 ◽  
Vol 204-208 ◽  
pp. 1976-1979
Author(s):  
Hang Sun ◽  
Xiao Jian Han ◽  
Xiu Yun Gao
Keyword(s):  
Dynamic Properties ◽  
Steel Tube ◽  
Design Parameters ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Space Model ◽  
Long Span ◽  
Current Design ◽  
Arch Bridges ◽  
The Impact

The calculation formula of the vertical fundamental frequency of arch bridge has been given in current design codes, in which the rise-span ratio is the only variable on condition that the structure mass and stiffness are known. However, the dynamic properties of long-span concrete filled steel tube arch bridges have their own characteristics, which are influenced by a series of factors. Thus this article establishes a space model of a concrete-filled steel tube arch bridge. By analyzing the main design parameters’ influence on the structure dynamic properties, including rise-span ratios, arch-axis coefficient and wide-span ratios, some of conclusions has been made, which can be used for further research of the impact effect and earthquake dynamic response, and provide the necessary basis for the dynamic design of bridges of this kind

scholarly journals Current assessment results of the efficacy and safety of scleroplasty in progressive myopia

2021 ◽  
Vol 14 (1) ◽  
pp. 96-103
Author(s):  
E. N. Iomdina ◽  
E. P. Tarutta ◽  
G. A. Markosian ◽  
J. I. Gavrilova
Keyword(s):  
Plastic Material ◽  
Biologically Active ◽  
Efficacy And Safety ◽  
Short Term ◽  
Current Assessment ◽  
Progressive Myopia ◽  
Long Term Observation ◽  
The Impact ◽  
Observation Results

The purpose of the review is to analyze the data of recent studies (performed in the last two decades) of the efficacy and safety of sclera reinforcement surgeries for progressive myopia in children and adults. Short-term and long-term observation results are presented, indicating the impact of the initial degree of myopia, the patient's age, surgical technique and the choice of plastic material on the outcome of the intervention and the further course of the myopic process. The advantages of a biologically active synthetic graft are described, which makes it possible to deposit drugs that stimulate scleral crosslinking and have a biomechanical, trophic and hemodynamic effect. Crosslinking of scleral collagen is a promising approach to the treatment of myopia.

scholarly journals Nrf2 Enhances Cholangiocyte Expansion in Pten-Deficient Livers

2013 ◽  
Vol 34 (5) ◽  
pp. 900-913 ◽  
Author(s):  
Keiko Taguchi ◽  
Ikuo Hirano ◽  
Tohru Itoh ◽  
Minoru Tanaka ◽  
Atsushi Miyajima ◽  
...  
Keyword(s):  
Double Mutant ◽  
Target Genes ◽  
Nuclear Accumulation ◽  
Dependent Manner ◽  
Double Deletion ◽  
Polycystic Liver ◽  
Long Term Observation ◽  
The Impact ◽  
Abnormal Expansion

Keap1-Nrf2 system plays a central role in the stress response. While Keap1 ubiquitinates Nrf2 for degradation under unstressed conditions, this Keap1 activity is abrogated in response to oxidative or electrophilic stresses, leading to Nrf2 stabilization and coordinated activation of cytoprotective genes. We recently found that nuclear accumulation of Nrf2 is significantly increased by simultaneous deletion of Pten and Keap1, resulting in the stronger activation of Nrf2 target genes. To clarify the impact of the cross talk between the Keap1-Nrf2 and Pten–phosphatidylinositide 3-kinase–Akt pathways on the liver pathophysiology, in this study we have conducted closer analysis of liver-specificPten::Keap1double-mutant mice (Pten::Keap1-Alb mice). The Pten::Keap1-Alb mice were lethal by 1 month after birth and displayed severe hepatomegaly with abnormal expansion of ductal structures comprising cholangiocytes in a Nrf2-dependent manner. Long-term observation of Pten::Keap1-Alb::Nrf2+/−mice revealed that the Nrf2-heterozygous mice survived beyond 1 month but developed polycystic liver fibrosis by 6 months. Gsk3 directing the Keap1-independent degradation of Nrf2 was heavily phosphorylated and consequently inactivated by the double deletion ofPtenandKeap1genes. Thus, liver-specific disruption ofKeap1andPtenaugments Nrf2 activity through inactivation of Keap1-dependent and -independent degradation of Nrf2 and establishes the Nrf2-dependent molecular network promoting the hepatomegaly and cholangiocyte expansion.

Assessment of exposure loads of chemicals in workers of the main professions of aluminum production in Eastern Siberia

2019 ◽  
Vol 1 (7) ◽  
pp. 406-411 ◽  
Author(s):  
Nina M. Meshchakova ◽  
Alexey V. Merinov ◽  
Salim F. Shayakhmetov ◽  
Lyudmila G. Lisetskaya
Keyword(s):  
Aluminum Electrolysis ◽  
Aluminum Production ◽  
Electrolysis Cell ◽  
Chemical Factor ◽  
Professional Groups ◽  
Harmful Substances ◽  
The Aluminum Industry ◽  
Long Term Observation ◽  
The Impact

Introduction. In the production of aluminum, one of the main adverse factors is the air pollution of the working area with f uorine-containing compounds and dust-gas-aerosol mixture, the impact of which can lead to health problems in workers. When establishing the connection of morbidity with the profession, it is important to assess the exposure loads of harmful substances. T is aspect of research in the aluminum industry is not suf iiently covered in the literature. T e aim of the study is to quantify the exposure loads of priority toxicants in workers of the main professions of aluminum production, depending on the applied technologies of aluminum electrolysis. Materials and methods. Exposure loads (EL) of chemicals at workers of aluminum production were calculated taking into account the data of a long-term assessment of the working area air for the content of the main harmful substances in workshops with technology of self-baking anode (TSA) and modernized using technology of prebaked anode (TPA). Results. It has been established that with the use of the traditional electrolysis technology (TSA), the average annual EL indicators in the professions of the electrolysis cell, anodechik and crane operators f uctuated noticeably in the dynamics of long-term observation, exceeding the indicators of the control EL. It is shown that the modernized electrolysis technology (TPA) allows to reduce the EL indicators of chemicals, with the exception of hydrof uoride — one of the priority components of the chemical factor. T e actual EL indicators of this substance in the professional groups did not depend on the applied electrolysis technology and, as before, exceeded the EL control indicators. Conclusions: Calculations of EL by harmful substances in the production of aluminum have shown that when using TSA, electrolysis cells and anodetes experience the greatest EL, exceeding control indicators, and the lowest  — crane operators. T e transition to a modernized TPA leads to a decrease in the EL indicators, with the exception of the hydrof uoride, a priority component of the chemical factor.

Rim Instant Release Radionuclide Inventory From French High Burnup Spent UOX Fuel

2009 ◽  
Vol 1193 ◽  
Author(s):  
D. Roudil ◽  
C. Jegou ◽  
V. Broudic ◽  
M. Tribet
Keyword(s):  
Small Volume ◽  
Source Term ◽  
Nuclear Waste Repository ◽  
Spent Fuel ◽  
Waste Container ◽  
High Burnup ◽  
Radionuclide Release ◽  
Long Term Behavior ◽  
The Impact

AbstractTo assess the long-term behavior of spent fuel in a nuclear waste repository, the chemical reactions between the fuel and possible intruding water must be understood and the resulting radionuclide release must be quantified. The instant release fraction (IRF) source term assumed to be instantaneously accessible to water after the failure of the waste container. Some IRF values for different kinds of spent fuel are available in the literature. However, the possible contribution the rim restructured zone for high-burnup UOX fuels, was not necessary taken into account. A specific study of the leaching behavior of the rim zone has been carried out on a UOX fuel sample with a burnup of 60 GWd·t-1 and 2.8% FGR. The 134/137Cs and 90Sr rim IRF are effectively higher than the gap and grain boundary inventories (respectively 4.4 wt% and 0.3 wt% of the total Cs and Sr inventories). Nevertheless because of the relative small volume of this zone in the pellet, the impact of the rim inventory appears to be limited and the complete Cs and Sr IRF (gap, grain boundaries and rim), were estimated at 1.85 and 0.3 wt%, respectively

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