scholarly journals Micro-mechanical investigation of railway ballast behavior under cyclic loading in a box test using DEM: effects of elastic layers and ballast types

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Nishant Kumar ◽  
Bettina Suhr ◽  
Stefan Marschnig ◽  
Peter Dietmaier ◽  
Christof Marte ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Early Stage ◽  
Damage Model ◽  
Simulation Models ◽  
Railway Track ◽  
Maintenance Cost ◽  
Particle Movement ◽  
Railway Ballast ◽  
Elastic Layers ◽  
The Impact

Abstract Ballasted tracks are the commonly used railway track systems with constant demands for reducing maintenance cost and improved performance. Elastic layers are increasingly used for improving ballasted tracks. In order to better understand the effects of elastic layers, physical understanding at the ballast particle level is crucial. Here, discrete element method (DEM) is used to investigate the effects of elastic layers – under sleeper pad ($$\text {USP}$$USP) at the sleeper/ballast interface and under ballast mat ($$\text {UBM}$$UBM) at the ballast/bottom interface – on micro-mechanical behavior of railway ballast. In the DEM model, the Conical Damage Model (CDM) is used for contact modelling. This model was calibrated in Suhr et al. (Granul Matter 20(4):70, 2018) for the simulation of two different types of ballast. The CDM model accounts for particle edge breakage, which is an important phenomenon especially at the early stage of a tamping cycle, and thus essential, when investigating the impact of elastic layers in the ballast bed. DEM results confirm that during cyclic loading, $$\text {USP}$$USP reduces the edge breakage at the sleeper/ballast interface. On the other hand, $$\text {UBM}$$UBM shows higher particle movement throughout the ballast bed. Both the edge breakage and particle movement in the ballast bed are found to influence the sleeper settlement. Micro-mechanical investigations show that the force chain in deeper regions of the ballast bed is less affected by $$\text {USP}$$USP for the two types of ballast. Conversely, dense lateral forces near to the box bottom were seen with $$\text {UBM}$$UBM. The findings are in good (qualitative) agreement with the experimental observations. Thus, DEM simulations can aid to better understand the micro-macro phenomena for railway ballast. This can help to improve the track components and track design based on simulation models taking into account the physical behavior of ballast. Graphical Abstract

scholarly journals Land Subsidence monitoring 2016 - 2018 analysis using GNSS CORS UDIP and DinSAR in Semarang

2019 ◽  
Author(s):  
BD Yuwono ◽  
M Awaluddin ◽  
Najib .
Keyword(s):  
Land Subsidence ◽  
Early Stage ◽  
Base Station ◽  
Capital City ◽  
Maintenance Cost ◽  
Subsidence Rate ◽  
The North ◽  
Gps Observation ◽  
Subsidence Monitoring ◽  
The Impact

Land Subsidence is phenomena likey common and occurred due to natural cause, loading, and geological setting. In the coastal area land subsidence became worse, cause influence by sea-level rise, The impact land subsidence can lead to wider expansion (flooding area called rob), damage or cracking construction/building and large of maintenance cost. Semarang is the capital city in Central Jawa have experienced in land subsidence in several decades. The north of Semarang was reported a higher rate of land subsidence compared with the south. It was believed that the land subsidence areas were affected by young alluvium, ground extraction and a load of the building. To anticipate, land subsidence should be monitored and detected in an early stage. The most effective way of monitoring land subsidence using GPS, DInSAR to evaluate the characteristic of land subsidence. The GPS observation was conducted in 2016 – 2018 using CORS UDIP as a base station and Sentinel Data was conducted to analyzed the subsidence rate in Semarang. The result showed land subsidence rate in several areas was distributed both spatially and temporally.

Study Behavior of Railway Ballast under Cyclic Loading

2014 ◽  
Vol 919-921 ◽  
pp. 1155-1159
Author(s):  
Tao Yong Zhou ◽  
Bin Hu ◽  
Bin Hua
Keyword(s):  
Numerical Simulation ◽  
Cyclic Loading ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Railway Track ◽  
Experimental Facility ◽  
Railway Ballast ◽  
Study Behavior ◽  
Rate Of Increase ◽  
Simulation Results

Densification and settlement are two important behavior parameters of railway ballast under cyclic loading. This paper presents numerical simulation using discrete element method which studies the evolution of densification of railway ballast in specified region under cyclic loading. The simulation results show that with the increase of cyclic loading time, the densification of railway ballast under sleeper is also increasing, and the rate of increase becomes smaller and smaller. This paper presents a new full-scale complete railway track loading experimental facility which studies the evolution of settlement of ballasted railway track under cyclic loading. The experimental results show that with the increase of number of load cycles, the settlement of ballasted railway track is also increasing, and the rate of increase becomes smaller and smaller.

KAJIAN DAMPAK KEBIJAKAN PENUTUPAN LOKALISASI TELEJU OLEH PEMERINTAH KOTA PEKANBARU

2017 ◽  
Vol 15 (2) ◽  
pp. 78
Author(s):  
M. Zainuddin
Keyword(s):  
Social Order ◽  
Qualitative Method ◽  
Negative Impact ◽  
Early Stage ◽  
Policy Research ◽  
Research Approach ◽  
Policy Content ◽  
The Government ◽  
Closure Policy ◽  
The Impact

This research to analyze the impact of closure policy Teleju brothel by Pekanbaru govermentin 2010. Guidelines for works are Pekanbaru Local Regulations No. 12 of 2008 on Social Order-liness. Closure this brothel inflicts positive and negative impact for society.The research wasconducted to obtain early stage formula for the government to take action against the prostitu-tion activities. This research uses policy research approach with a qualitative method, becausein prostitution activities and prohibition by goverment is an assessment that needs to be done byanalyzing documents and unstructured interview.The results showed that after the closing of the Teleju brothel have an impact on the deploy-ment of a prostitution and affect the economy of the surrounding residents. Government seeksto tackle prostitution in Pekanbaru by moving the brothel, conduct regular raids and providetraining. The effort is considered to be less than the maximum because the handling is not basedon the root of the problem and not programmed properly. There are several causes of failure ofgovernment to overcome the prostitution problem in Pekanbaru, including: policy content isless focus on the prostitution problem, the government did not proceeds with data, lack of finan-cial support, contra productive programs between local government with the police and TNI,and the policy object is difficult to be given understanding.

Fluoxetine Protects against Dendritic Spine Loss in Middle-aged APPswe/PSEN1dE9 Double Transgenic Alzheimer’s Disease Mice

2020 ◽  
Vol 17 (1) ◽  
pp. 93-103 ◽  
Author(s):  
Jing Ma ◽  
Yuan Gao ◽  
Wei Tang ◽  
Wei Huang ◽  
Yong Tang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Dendritic Spines ◽  
Dendritic Spine ◽  
Early Stage ◽  
Learning Ability ◽  
Middle Aged ◽  
Protein Levels ◽  
Spine Pathology ◽  
The Impact

Background: Studies have suggested that cognitive impairment in Alzheimer’s disease (AD) is associated with dendritic spine loss, especially in the hippocampus. Fluoxetine (FLX) has been shown to improve cognition in the early stage of AD and to be associated with diminishing synapse degeneration in the hippocampus. However, little is known about whether FLX affects the pathogenesis of AD in the middle-tolate stage and whether its effects are correlated with the amelioration of hippocampal dendritic dysfunction. Previously, it has been observed that FLX improves the spatial learning ability of middleaged APP/PS1 mice. Objective: In the present study, we further characterized the impact of FLX on dendritic spines in the hippocampus of middle-aged APP/PS1 mice. Results: It has been found that the numbers of dendritic spines in dentate gyrus (DG), CA1 and CA2/3 of hippocampus were significantly increased by FLX. Meanwhile, FLX effectively attenuated hyperphosphorylation of tau at Ser396 and elevated protein levels of postsynaptic density 95 (PSD-95) and synapsin-1 (SYN-1) in the hippocampus. Conclusion: These results indicated that the enhanced learning ability observed in FLX-treated middle-aged APP/PS1 mice might be associated with remarkable mitigation of hippocampal dendritic spine pathology by FLX and suggested that FLX might be explored as a new strategy for therapy of AD in the middle-to-late stage.

scholarly journals Development of fragility curves for railway ballast and embankment scour due to overtopping flood flow

2016 ◽  
Author(s):  
Ryota Tsubaki ◽  
Koji Ichii ◽  
Jeremy D. Bricker ◽  
Yoshihisa Kawahara
Keyword(s):  
Spatial Distribution ◽  
Failure Probability ◽  
Fragility Curves ◽  
Railway Track ◽  
Single Track ◽  
Hydraulic Analysis ◽  
Railway Ballast ◽  
Log Normal ◽  
Flood Flow

Abstract. Fragility curves evaluating risk of railway track ballast and embankment fill scour were developed. To develop fragility curves, two well-documented single-track railway washouts during two recent floods in Japan were investigated. Type of damage to the railway was categorized into no damage, ballast scour, and embankment scour, in order of damage severity. Railway overtopping surcharge for each event was estimated via hydrologic and hydraulic analysis. Normal and log-normal fragility curves were developed based on failure probability derived from field records. A combined ballast and embankment scour model was validated by comparing the spatial distribution of railway scour with the field damage record.

Statistical micromechanical damage model for SH-SFRC under tensile load considering the interfacial slip-softening and matrix spalling effects

2021 ◽  
pp. 105678952110112
Author(s):  
Hehua Zhu ◽  
Xiangyang Wei ◽  
J Woody Ju ◽  
Qing Chen ◽  
Zhiguo Yan ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Steel Fiber ◽  
Damage Model ◽  
Fiber Reinforced Concrete ◽  
Uniaxial Tensile ◽  
Interfacial Slip ◽  
Fiber Reinforced ◽  
Micromechanical Damage ◽  
The Impact ◽  
Micromechanical Damage Model

Strain hardening behavior can be observed in steel fiber reinforced concretes under tensile loads. In this paper, a statistical micromechanical damage framework is presented for the strain hardening steel fiber reinforced concrete (SH-SFRC) considering the interfacial slip-softening and matrix spalling effects. With a linear slip-softening interface law, an analytical model is developed for the single steel fiber pullout behavior. The crack bridging effects are reached by averaging the contribution of the fibers with different inclined angles. Afterwards, the traditional snubbing factor is modified by considering the fiber snubbing and the matrix spalling effects. By adopting the Weibull distribution, a statistical micromechanical damage model is established with the fracture mechanics based cracking criteria and the stress transfer distance. The comparison with the experimental results demonstrates that the proposed framework is capable of reproducing the SH-SFRC’s uniaxial tensile behavior well. Moreover, the impact of the interfacial slip-softening and matrix spalling effects are further discussed with the presented framework.

scholarly journals Effect of COVID-19 on Thoracic Oncology Surgery in Spain: A Spanish Thoracic Surgery Society (SECT) Survey

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2897
Author(s):  
Néstor Martínez-Hernández ◽  
Usue Caballero Silva ◽  
Alberto Cabañero Sánchez ◽  
José Luis Campo-Cañaveral de la Cruz ◽  
Andrés Obeso Carillo ◽  
...  
Keyword(s):  
Overall Response Rate ◽  
Early Stage ◽  
Care Delivery ◽  
Public Hospitals ◽  
Clinical Activity ◽  
Spanish Society ◽  
Lung Cancer Patients ◽  
Oncological Patients ◽  
Multiple Choice Questionnaire ◽  
The Impact

After the first wave of COVID-19, the Spanish Society of Thoracic Surgeons (SECT) surveyed its members to assess the impact of the pandemic on thoracic oncology surgery in Spain. In May 2020, all SECT members were invited to complete an online, 40-item, multiple choice questionnaire. The questionnaire was developed by the SECT Scientific Committee and sent via email. The overall response rate was 19.2%. The respondents answered at least 91.5% of the items, with only one exception (a question about residents). Most respondents (89.3%) worked in public hospitals. The reported impact of the pandemic on routine clinical activity was considered extreme or severe by 75.5% of respondents (25.5% and 50%, respectively). Multidisciplinary tumour boards were held either with fewer members attending or through electronic platforms (44.6% and 35.9%, respectively). Surgical activity decreased by 95.7%, with 41.5% of centers performing surgery only on oncological patients and 11.7% only in emergencies. Nearly 60% of respondents reported modifying standard protocols for early-stage cancer and in the preoperative workup. Most centers (≈80%) reported using full personal protective equipment when operating on COVID-19 positive patients. The COVID-19 pandemic severely affected thoracic oncology surgery in Spain. The lack of common protocols led to a variable care delivery to lung cancer patients.

scholarly journals Miniaturization and Automation of a Human In Vitro Blood–Brain Barrier Model for the High-Throughput Screening of Compounds in the Early Stage of Drug Discovery

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 892
Author(s):  
Elisa L. J. Moya ◽  
Elodie Vandenhaute ◽  
Eleonora Rizzi ◽  
Marie-Christine Boucau ◽  
Johan Hachani ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Blood Brain Barrier ◽  
Early Stage ◽  
Molecular Transport ◽  
Brain Barrier ◽  
Blood Brain ◽  
Cns Drugs ◽  
The Impact ◽  
The Brain

Central nervous system (CNS) diseases are one of the top causes of death worldwide. As there is a difficulty of drug penetration into the brain due to the blood–brain barrier (BBB), many CNS drugs treatments fail in clinical trials. Hence, there is a need to develop effective CNS drugs following strategies for delivery to the brain by better selecting them as early as possible during the drug discovery process. The use of in vitro BBB models has proved useful to evaluate the impact of drugs/compounds toxicity, BBB permeation rates and molecular transport mechanisms within the brain cells in academic research and early-stage drug discovery. However, these studies that require biological material (animal brain or human cells) are time-consuming and involve costly amounts of materials and plastic wastes due to the format of the models. Hence, to adapt to the high yields needed in early-stage drug discoveries for compound screenings, a patented well-established human in vitro BBB model was miniaturized and automated into a 96-well format. This replicate met all the BBB model reliability criteria to get predictive results, allowing a significant reduction in biological materials, waste and a higher screening capacity for being extensively used during early-stage drug discovery studies.

scholarly journals Evaluating the effectiveness of machine acquisitions and design by the impact on maintenance cost – a case study

2020 ◽  
Vol 53 (3) ◽  
pp. 25-30
Author(s):  
M. Hane Hagström ◽  
K. Gandhi ◽  
D. Bergsjö ◽  
A. Skoogh
Keyword(s):  
Maintenance Cost ◽  
The Impact
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