scholarly journals Comparative Study on Interface Elements, Thin-Layer Elements, and Contact Analysis Methods in the Analysis of High Concrete-Faced Rockfill Dams

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Xiao-xiang Qian ◽  
Hui-na Yuan ◽  
Quan-ming Li ◽  
Bing-yin Zhang
Keyword(s):  
Thin Layer ◽  
Contact Stress ◽  
Contact Analysis ◽  
Interface Element ◽  
In Situ Observation ◽  
Observation Data ◽  
Analysis Methods ◽  
Dam Deformation ◽  
Concrete Face

This paper presents a study on the numerical performance of three contact simulation methods, namely, the interface element, thin-layer element, and contact analysis methods, through the analysis of the contact behavior between the concrete face slab and the dam body of a high concrete-faced rockfill dam named Tianshengqiao-I in China. To investigate the accuracy and limitations of each method, the simulation results are compared in terms of the dam deformation, contact stress along the interface, stresses in the concrete face slab, and separation of the concrete face slab from the cushion layer. In particular, the predicted dam deformation and slab separation are compared with the in-situ observation data to classify these methods according to their agreement with the in-situ observations. It is revealed that the interface element and thin-layer element methods have their limitations in predicting contact stress, slab separation, and stresses in the concrete face slab if a large slip occurs. The contact analysis method seems to be the best choice whether the separation is finite or not.

Comparative study of stress analysis of gears with different helix angle using the ISO 6336 standard and tooth contact analysis methods

2016 ◽  
Vol 230 (7-8) ◽  
pp. 1350-1358 ◽  
Author(s):  
Layue Zhao ◽  
Robert C Frazer ◽  
Brian Shaw
Keyword(s):  
Stress Analysis ◽  
Contact Stress ◽  
Helix Angle ◽  
Contact Analysis ◽  
Bending Stress ◽  
Contact Ratio ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Iso Standard ◽  
Analysis Methods

With increasing demand for high speed and high power density gear applications, the need to optimise gears for minimum stress, noise and vibration becomes increasingly important. ISO 6336 contact and bending stress analysis are used to determine the surface load capacity and tooth bending strength but dates back to 1956 and although it is constantly being updated, a review of its performance is sensible. Methods to optimise gear performance include the selection of helix angle and tooth depth to optimise overlap ratio and transverse contact ratio and thus the performance of ISO 6336 and tooth contact analysis methods requires confirmation. This paper reviews the contact and bending stress predicted with four involute gear geometries and proposes recommendations for stress calculations, including a modification to contact ratio factor Zɛ which is used to predict contact stress and revisions to form factor YF and helix angle factor Yβ which are cited to evaluate bending stress. The results suggest that there are some significant deviations in predicted bending and contact stress values between proposal methods and original ISO standard. However, before the ISO standard is changed, the paper recommends that allowable stress numbers published in ISO 6336-5 are reviewed because the mechanisms that initiate bending and contact fatigue have also changed and these require updating.

scholarly journals First evaluation of SMOS L2 soil moisture products using in situ observation data of MAVEX on the Mongolian Plateau in 2010 and 2011

2013 ◽  
Vol 7 (2) ◽  
pp. 30-35 ◽  
Author(s):  
Ichirow Kaihotsu ◽  
Keiji Imaoka ◽  
Hideyuki Fujii ◽  
Dambaravjaa Oyunbaatar ◽  
Tsutomu Yamanaka ◽  
...  
Keyword(s):  
Soil Moisture ◽  
In Situ Observation ◽  
Observation Data ◽  
Mongolian Plateau

Design of a Cabled Seafloor Observatory for Marine Ecological Environment Monitoring

2021 ◽  
Vol 55 (2) ◽  
pp. 17-24
Author(s):  
Chao Li ◽  
Yan Li ◽  
Rui Zhu ◽  
Yu-ze Song ◽  
Lei Yang
Keyword(s):  
Current System ◽  
Ecological Environment ◽  
Observation System ◽  
In Situ Observation ◽  
Observation Data ◽  
Environment Monitoring ◽  
State Monitoring ◽  
Seafloor Observation ◽  
Shore Station

Abstract Cabled seafloor in-situ observation systems have drawn much attention in recent years for their capability of facilitating long-term all-weather deep-sea data-intense marine observations. The Penglai in-situ seafloor observation system for ecological environment monitoring is proposed in this paper. The current system consists of an on-shore station, a primary node, and two secondary nodes, but more nodes can be hosted due to its scalability. A looped backbone network connects the on-shore station and primary nodes. Each primary node can host up to four secondary nodes, and each secondary node can host up to eight different sensors. Marine observation data and system work state data are collected and backed up by the on-shore station in a real-time manner. Users can access the ocean observation data via a web page interface. The proposed system has been deployed for more than half a year and will continue to work after that. The field experiment showed that the proposed system worked smoothly in system state monitoring and marine data acquisition. A large amount of oceanographic data with videos has been achieved for future studies.

Fabrication of High Quality Poly-Si From Fluorinated Precursors

1993 ◽  
Vol 297 ◽  
Author(s):  
Shin-Ichi Ishihara ◽  
Deyan He ◽  
Tetsuya Akasaka ◽  
Yuzoh Araki ◽  
Isamu Shimizu
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Electrical Conductivity ◽  
Thin Layer ◽  
Atomic Hydrogen ◽  
Solid Phase ◽  
Chemical Interaction ◽  
In Situ Observation ◽  
High Quality

Poly-Si thin films with grains 100–200 nm in dia. showing a highly ordered texture were grown from fluorinated precursors, SiFnHm (n+m=3), on a glass substrate at 300–400 °C with the aid of atomic hydrogen. According to the in situ observation by ellipsometry, the reconstruction was undergone in a solid phase stimulated by impinging atomic hydrogens within a thin layer of about 10 nm thick owing to the strong chemical interaction of the pair of H and F in Si-network. Both H and F were released efficiently from the network to the levels of 2 × 1020 cm−3 and (2−5) × 1019 cm−3, respectively. Dangling bonds were also efficiently passivated down to 4 × 1016 cm−3 with hydrogens diffused through the network. P-doped films showing electrical conductivity of 10−2 S/cm (300 °K) with the activation energy of 0.24 eV was obtained by alternately repeating the deposition of thin layer and the treatment with atomic hydrogens.

In situ observation of electrical property of thin-layer black phosphorus based on dry transfer method

2016 ◽  
Vol 9 (4) ◽  
pp. 045202 ◽  
Author(s):  
Xin Xin ◽  
Hai-Ming Zhao ◽  
Hui-Wen Cao ◽  
He Tian ◽  
Yi Yang ◽  
...  
Keyword(s):  
Electrical Property ◽  
Thin Layer ◽  
Black Phosphorus ◽  
In Situ Observation ◽  
Transfer Method

Numerical Simulation on the Sinking Process of Open Caisson with Particle Flow Code (PFC)

2013 ◽  
Vol 838-841 ◽  
pp. 831-834 ◽  
Author(s):  
Jian Wang ◽  
Li Sha Chai ◽  
Hao Wu
Keyword(s):  
Soil Structure ◽  
Fem Simulation ◽  
Particle Flow ◽  
Particle Flow Code ◽  
Solid Boundary ◽  
In Situ Observation ◽  
Observation Data ◽  
Servo Mechanism ◽  
Soil Flow

Sidewall pressure is important to open caisson design. However, FEM simulation for the sinking process of open caisson is quite difficult due to extremely large deformation including soil flow and solid boundary movement. In order to overcome this problem, Particle Flow Code (PFC), which is based upon discrete element method (DEM), was applied to simulate the whole sinking process of an open caisson using proposed load servo mechanism, and the variations of the sidewall pressure with sinking depth and elevation were investigated. The outcomes agree well with the in-situ observation data and the indoor experiment data, which verifies the feasibility of modeling the sinking process of open caissons using PFC and further studying their soil-structure interaction mechanisms from the microscopic prospect.

scholarly journals Research on Non-Invasive Laser Doppler Current Measurement for Hydrothermal Vents Flow Rates Profile

2020 ◽  
Vol 237 ◽  
pp. 07023
Author(s):  
Hongwei Zhang ◽  
Songhua Wu ◽  
Jintao Liu ◽  
Yuanshuai Zhang ◽  
Xiaomin Chen
Keyword(s):  
Hydrothermal Vents ◽  
In Situ Observation ◽  
Observation Data ◽  
Energy Materials ◽  
Flow Meter ◽  
Flow Rates ◽  
Non Invasive ◽  
Blind Area ◽  
Turbine Flow Meter

Hydrothermal vents play important roles in the dynamic process of the stratosphere and the circulation of energy materials. Nowadays, invasive devices such as vane-type flow meter and turbine flow meter are commonly utilized to estimate the flow rates of hydrothermal vents. In- situ observation data obtained by LDCP system and CFD methods will be combined to solve the blind area of LDCP system during in-situ observation measurements. The flow rates profiles obtained in this project will improve the research on the circulation of energy materials and mineralization.

scholarly journals A Remote-Sensing Method to Estimate Bulk Refractive Index of Suspended Particles from GOCI Satellite Measurements over Bohai Sea and Yellow Sea

2019 ◽  
Vol 10 (1) ◽  
pp. 23
Author(s):  
Deyong Sun ◽  
Zunbin Ling ◽  
Shengqiang Wang ◽  
Zhongfeng Qiu ◽  
Yu Huan ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Refractive Index ◽  
Spatial Distribution ◽  
Yellow Sea ◽  
Bohai Sea ◽  
Suspended Particles ◽  
In Situ Observation ◽  
Observation Data ◽  
Estimation Model

The bulk refractive index (np) of suspended particles, an apparent measure of particulate refraction capability and yet an essential element of particulate compositions and optical properties, is a critical indicator that helps understand many biogeochemical processes and ecosystems in marine waters. Remote estimation of np remains a very challenging task. Here, a multiple-step hybrid model is developed to estimate the np in the Bohai Sea (BS) and Yellow Sea (YS) through obtaining two key intermediate parameters (i.e., particulate backscattering ratio, Bp, and particle size distribution (PSD) slope, j) from remote-sensing reflectance, Rrs(λ). The in situ observed datasets available to us were collected from four cruise surveys during a period from 2014 to 2017 in the BS and YS, covering beam attenuation (cp), scattering (bp), and backscattering (bbp) coefficients, total suspended matter (TSM) concentrations, and Rrs(λ). Based on those in situ observation data, two retrieval algorithms for TSM and bbp were firstly established from Rrs(λ), and then close empirical relationships between cp and bp with TSM could be constructed to determine the Bp and j parameters. The series of steps for the np estimation model proposed in this study can be summarized as follows: Rrs (λ) → TSM and bbp, TSM → bp → cp → j, bbp and bp → Bp, and j and Bp → np. This method shows a high degree of fit (R2 = 0.85) between the measured and modeled np by validation, with low predictive errors (such as a mean relative error, MRE, of 2.55%), while satellite-derived results also reveal good performance (R2 = 0.95, MRE = 2.32%). A spatial distribution pattern of np in January 2017 derived from GOCI (Geostationary Ocean Color Imager) data agrees well with those in situ observations. This also verifies the satisfactory performance of our developed np estimation model. Applying this model to GOCI data for one year (from December 2014 to November 2015), we document the np spatial distribution patterns at different time scales (such as monthly, seasonal, and annual scales) for the first time in the study areas. While the applicability of our developed method to other water areas is unknown, our findings in the current study demonstrate that the method presented here can serve as a proof-of-concept template to remotely estimate np in other coastal optically complex water bodies.

scholarly journals Improved Understanding of Groundwater Storage Changes under the Influence of River Basin Governance in Northwestern China Using GRACE Data

2021 ◽  
Vol 13 (14) ◽  
pp. 2672
Author(s):  
Xin Liu ◽  
Litang Hu ◽  
Kangning Sun ◽  
Zhengqiu Yang ◽  
Jianchong Sun ◽  
...  
Keyword(s):  
River Basin ◽  
Groundwater Level ◽  
Regional Scale ◽  
Water Storage ◽  
Northwestern China ◽  
In Situ Observation ◽  
Observation Data ◽  
Groundwater Storage ◽  
Grace Data

Groundwater is crucial for economic development in arid and semiarid areas. The Shiyang River Basin (SRB) has the most prominent water use issues in northwestern China, and overexploited groundwater resources have led to continuous groundwater-level decline. The key governance planning project of the SRB was issued in 2007. This paper synthetically combines remote-sensing data from Gravity Recovery and Climate Experiment (GRACE) data and precipitation, actual evapotranspiration, land use, and in situ groundwater-level data to evaluate groundwater storage variations on a regional scale. Terrestrial water storage anomalies (TWSA) and groundwater storage anomalies (GWSA), in addition to their influencing factors in the SRB since the implementation of the key governance project, are analyzed in order to evaluate the effect of governance. The results show that GRACE-derived GWS variations are consistent with in situ observation data in the basin, with a correlation coefficient of 0.68. The GWS in the SRB had a slow downward trend from 2003 to 2016, and this increased by 0.38 billion m³/year after 2018. As the meteorological data did not change significantly, the changes in water storage are mainly caused by human activities, which are estimated by using the principle of water balance. The decline in GWS in the middle and lower reaches of the SRB has been curbed since 2009 and has gradually rebounded since 2014. GWS decreased by 2.2 mm EWH (equivalent water height) from 2011 to 2016, which was 91% lower than that from 2007 to 2010. The cropland area in the middle and lower reaches of the SRB also stopped increasing after 2011 and gradually decreased after 2014, while the area of natural vegetation gradually increased, indicating that the groundwater level and associated ecology significantly recovered after the implementation of the project.

scholarly journals Using Wi-Fi Signals from Mobile Devices to Determine Characteristics of Pedestrian Behavior in Public Spaces

2020 ◽  
pp. 036119812096109
Author(s):  
Eva Šimara ◽  
Pavla Kilnarová ◽  
Jiří Palacký ◽  
Radka Vašut
Keyword(s):  
Data Collection ◽  
Mobile Devices ◽  
Public Spaces ◽  
In Situ Observation ◽  
Observation Data ◽  
Data Logger ◽  
Pedestrian Behavior ◽  
Automated Data Collection

This paper presents an investigation into automated data collection, applied to pedestrians in public spaces. Three case studies conducted in Brno, Czech Republic, a typical, medium-sized city in Central Europe, were used to determine the accuracy of the proposed method. Data were recorded in two ways: (i) automated data collection, using a data logger constructed on the principle of a minicomputer to measure the intensity of Wi-Fi signals from mobile devices; and (ii) in situ observation. Data from in situ observation provided a basis for the comparison and verification of corresponding values from the automated data collection. The research framework of the paper comprises the determination of exact values for optimum characterization of pedestrian behavior in a given locality, taking into consideration conventions from previously published works: (i) the number of pedestrians ( N); (ii) speed ( u); (iii) flow ( q); and (iv) density ( k). The results of this study confirm that as the density of the street network increases, the accuracy of the data collected by the digital method decreases significantly. These findings indicate that the method is more suitable for projects focused on identifying major trends or shifts in pedestrian preferences when navigating city centers than for projects that require exact counts in specific locations at a given time.

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