Field testing of rocking foundations in cohesive soil: cyclic performance and footing mechanical response

2020 ◽  
Vol 57 (6) ◽  
pp. 828-839 ◽  
Author(s):  
Keshab Sharma ◽  
Lijun Deng
Keyword(s):  
Field Test ◽  
Large Scale ◽  
Mechanical Response ◽  
Field Testing ◽  
Cohesive Soil ◽  
Superior Performance ◽  
Unit Weight ◽  
Moment Capacity ◽  
Contact Areas ◽  
Rocking Foundations

This paper presents a field test program of a large-scale soil–footing-structure system designed with a rocking foundation in a cohesive soil to examine the behaviour of the system and to provide case histories for possible performance-based seismic design of foundations. The rocking system was subjected to slow cyclic loadings at various drift ratios up to 7%. Twenty-four tests were conducted for foundations with varying initial factors of safety against the bearing failure, loading directions, rotation amplitudes, and embedment. A geotechnical investigation was carried out to determine soil properties before and after the experiments. The system performance indices, such as damping, stiffness, settlement, and re-centering capability, were quantified and compared with the published literature. Field test results showed that the strength and unit weight of soils at footing edges were increased due to rocking, for the present cohesive soil. The rocking moment capacity increased slightly with the increasing soil strength. An empirical equation for the secant stiffness was developed. The rocking system on the cohesive soil exhibited superior performance in terms of small residual settlement and large re-centering capability. Footing’s mechanical response was quantified using strain gauge readings. The footing remained elastic in tension; the transient soil–footing contact areas were estimated with strain gauges, and they agreed very well with the measured or calculated contact areas.

scholarly journals PENGEMBANGAN MEDIA PANLINTARMATIKA (PAPAN PERKALIAN PINTAR MATEMATIKA) MATERI PERKALIAN UNTUK SISWA SEKOLAH DASAR

2021 ◽  
Vol 2 (1) ◽  
pp. 41-47
Author(s):  
Hasna Nur Afifah ◽  
Meita Fitrianawati
Keyword(s):  
Data Analysis ◽  
Field Test ◽  
Large Scale ◽  
Field Testing ◽  
Small Scale ◽  
Quantitative Data Analysis ◽  
Scale Field ◽  
Large Scale Field ◽  
The Media ◽  
Information Collecting

This study aims to 1) find out the steps in developing Panlintarmatika learning media, 2) know the feasibility of developing Panlintarmatika learning media based on experts.  This study is a type of Research and Development (RD) research using the Borg and Gal model which consists of: (1) research and information collecting, (2) planning, (3) developing preliminary from a product, (4) prelimunary field testing,  (5) main product revision, (6) main field testing, (7) operational product revision (8) operational field testing.  The trial subjects used were 18 grade 2 students and teachers at SD N Kalangan.  Data collection techniques in the form of observation, interviews and questionnaires.  Data analysis includes quantitative data analysis and qualitative data analysis.  The results showed that the validation of the media experts received a score of 60 in the "Very good" category, the validation of the material experts received a score of 42 in the "Good" category and the learning expert received a score of 60 in the "Good" category.  The results of the small-scale field test students get a score of 100 with the category "Very Good" and the teacher gets a score of 94 with the category "Very Good".  Large-scale field test results students get a score of 100 with the category "Very Good" and the teacher scores 98 with a score of "Very Good" It can be concluded that the Panlintarmatika learning media is feasible and can be used as class 2 learning multiplication material

scholarly journals On the effects of membrane viscosity on transient red blood cell dynamics

Soft Matter ◽  
2020 ◽  
Vol 16 (26) ◽  
pp. 6191-6205 ◽  
Author(s):  
Fabio Guglietta ◽  
Marek Behr ◽  
Luca Biferale ◽  
Giacomo Falcucci ◽  
Mauro Sbragaglia
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Blood Circulation ◽  
Hydraulic Properties ◽  
Large Scale ◽  
Mechanical Response ◽  
Cell Dynamics ◽  
Membrane Viscosity

Computational Fluid Dynamics is currently used to design and improve the hydraulic properties of biomedical devices, wherein the large scale blood circulation needs to be simulated by accounting for the mechanical response of RBCs at the mesoscale.

Continuum Description of the Time- and Strain-Dependent Poisson’s Ratio of Ligament Under Finite Deformation

2013 ◽  
Author(s):  
Aaron M. Swedberg ◽  
Shawn P. Reese ◽  
Steve A. Maas ◽  
Benjamin J. Ellis ◽  
Jeffrey A. Weiss
Keyword(s):  
Large Scale ◽  
Mechanical Response ◽  
Tensile Deformation ◽  
Large Strain ◽  
Fiber Direction ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Poisson's Ratios ◽  
Poisson’S Ratios ◽  
Strain Dependent

Ligament volumetric behavior controls fluid and thus nutrient movement as well as the mechanical response of the tissue to applied loads. The reported Poisson’s ratios for tendon and ligament subjected to tensile deformation loading along the fiber direction are large, ranging from 0.8 ± 0.3 in rat tail tendon fascicles [1] to 2.98 ± 2.59 in bovine flexor tendon [2]. These Poisson’s ratios are indicative of volume loss and thus fluid exudation [3,4]. We have developed micromechanical finite element models that can reproduce both the characteristic nonlinear stress-strain behavior and large, strain-dependent Poisson’s ratios seen in tendons and ligaments [5], but these models are computationally expensive and unfeasible for large scale, whole joint models. The objectives of this research were to develop an anisotropic, continuum based constitutive model for ligaments and tendons that can describe strain-dependent Poisson’s ratios much larger than the isotropic limit of 0.5. Further, we sought to demonstrate the ability of the model to describe experimental data, and to show that the model can be combined with biphasic theory to describe the rate- and time-dependent behavior of ligament and tendon.

Development of a Reproducible Method of Formulating and Testing Drilling Fluids

1969 ◽  
Vol 9 (04) ◽  
pp. 403-411 ◽  
Author(s):  
B.K. Sinha ◽  
Harvey T. Kennedy
Keyword(s):  
Large Scale ◽  
Drilling Fluid ◽  
Flow Characteristics ◽  
Field Testing ◽  
Test Methods ◽  
Water Evaporation ◽  
Fluid Loss ◽  
Drilling Fluids ◽  
Testing Procedures ◽  
Asymptotic Values

Abstract Recommendations are made for obtaining consistent and reproducible test data on drilling fluids having identical composition. Previously, such a procedure has been difficult to accomplish even when the fluids were mixed in similar equipment. A survey of work in this area indicates that previous methods have been unsatisfactory because previous methods have been unsatisfactory because (1) the muds are extremely sensitive to the duration and violence of agitation during a normal mixing routine, and (2) gelling of the muds occurs before the properties can reach constant values. This gelling is caused by water evaporation resulting from the increase in temperature associated with the agitation. The work shows that these problems largely can be overcome by (1) agitating the constituents of the drilling fluid more vigorously, (2) maintaining a fairly constant temperature, and(3) Protecting the fluid from evaporation. When these steps are followed, the fluid properties approach asymptotic values that do not change by prolonged or accelerated agitation or by aging for a month. The time required to reach asymptotic values or a stabilized state is from 2 to 6 hours and is a function of the mud composition. Introduction Preparation of drilling fluids in the laboratory to determine their suitability to meet specific drilling requirements or to serve as a base fluid to evaluate the effectiveness of thinners, dispersants or other additives normally begins with combining measured quantities of the constituents and stirring them for a short time in a low-speed mixer. This is done to obtain a uniform mixture and to hydrate clays. Then the fluid is further agitated in a higher-speed device (Hamilton Beach mixer or Waring blender) to disperse more thoroughly and clay particles The biggest obstacle in the laboratory investigation of drilling fluids has been the lack of a method of producing a mixture by which reproducible results of the measured properties could be obtained. Numerous investigators have encountered this difficulty. Prior to 1929, density was the only property of mud that customarily was measured. The use of Wyoming bentonite on a large scale after 1929 was mainly responsible for the development of more elaborate testing procedures and for the application of the principles of colloid chemistry to the drilling fluids. Ambrose and Loomis in 1931 were among the first to recognize the plastic flow characteristics of drilling fluids, although Bingham in 1916 had observed The same phenomenon with dilute clay suspensions. Marsh introduced the Marsh funnel for field testing in 1931. By this time, non-Newtonian characteristics of drilling fluids were established. The Stormer and MacMichael viscometers were used to study the rheological properties of the fluids. In the 1930's and early 1940's, the work conducted by several investigators contributed toward a better understanding of drilling fluids. In the mid 1930's, fluid-loss and the associated mud-cake-forming properties of drilling fluids were recognized as important to the behavior of these fluids. The other properties of drilling fluids, including gel strength, pH, and sand content soon were recognized. In 1937, API published its first recommended procedure for test methods. Since that time, these procedures have been revised periodically. The latest edition, RP-13B, was published in 1961 However, in spite of the recognized need for a method of mixing that provides drilling fluids with stabilized properties, no such method previously has been described. SPEJ P. 403

scholarly journals 3D Photon-To-Digital Converter for Radiation Instrumentation: Motivation and Future Works

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 598
Author(s):  
Jean-François Pratte ◽  
Frédéric Nolet ◽  
Samuel Parent ◽  
Frédéric Vachon ◽  
Nicolas Roy ◽  
...  
Keyword(s):  
Large Scale ◽  
Single Photon ◽  
Time Of Flight ◽  
Digital Signal ◽  
Liquid Argon ◽  
Cmos Technology ◽  
System Level ◽  
Superior Performance ◽  
Digital Converter ◽  
Positron Emission

Analog and digital SiPMs have revolutionized the field of radiation instrumentation by replacing both avalanche photodiodes and photomultiplier tubes in many applications. However, multiple applications require greater performance than the current SiPMs are capable of, for example timing resolution for time-of-flight positron emission tomography and time-of-flight computed tomography, and mitigation of the large output capacitance of SiPM array for large-scale time projection chambers for liquid argon and liquid xenon experiments. In this contribution, the case will be made that 3D photon-to-digital converters, also known as 3D digital SiPMs, have a potentially superior performance over analog and 2D digital SiPMs. A review of 3D photon-to-digital converters is presented along with various applications where they can make a difference, such as time-of-flight medical imaging systems and low-background experiments in noble liquids. Finally, a review of the key design choices that must be made to obtain an optimized 3D photon-to-digital converter for radiation instrumentation, more specifically the single-photon avalanche diode array, the CMOS technology, the quenching circuit, the time-to-digital converter, the digital signal processing and the system level integration, are discussed in detail.

scholarly journals Multiscale Semantic Feature Optimization and Fusion Network for Building Extraction Using High-Resolution Aerial Images and LiDAR Data

2021 ◽  
Vol 13 (13) ◽  
pp. 2473
Author(s):  
Qinglie Yuan ◽  
Helmi Zulhaidi Mohd Shafri ◽  
Aidi Hizami Alias ◽  
Shaiful Jahari Hashim
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Spatial Information ◽  
Feature Fusion ◽  
Aerial Images ◽  
Semantic Gap ◽  
Superior Performance ◽  
Lidar Data ◽  
Building Extraction ◽  
Hierarchical Features

Automatic building extraction has been applied in many domains. It is also a challenging problem because of the complex scenes and multiscale. Deep learning algorithms, especially fully convolutional neural networks (FCNs), have shown robust feature extraction ability than traditional remote sensing data processing methods. However, hierarchical features from encoders with a fixed receptive field perform weak ability to obtain global semantic information. Local features in multiscale subregions cannot construct contextual interdependence and correlation, especially for large-scale building areas, which probably causes fragmentary extraction results due to intra-class feature variability. In addition, low-level features have accurate and fine-grained spatial information for tiny building structures but lack refinement and selection, and the semantic gap of across-level features is not conducive to feature fusion. To address the above problems, this paper proposes an FCN framework based on the residual network and provides the training pattern for multi-modal data combining the advantage of high-resolution aerial images and LiDAR data for building extraction. Two novel modules have been proposed for the optimization and integration of multiscale and across-level features. In particular, a multiscale context optimization module is designed to adaptively generate the feature representations for different subregions and effectively aggregate global context. A semantic guided spatial attention mechanism is introduced to refine shallow features and alleviate the semantic gap. Finally, hierarchical features are fused via the feature pyramid network. Compared with other state-of-the-art methods, experimental results demonstrate superior performance with 93.19 IoU, 97.56 OA on WHU datasets and 94.72 IoU, 97.84 OA on the Boston dataset, which shows that the proposed network can improve accuracy and achieve better performance for building extraction.

Molecular Dynamics Modeling the Nano-Identation of Titanium

2021 ◽  
Author(s):  
Peiqiang Yang ◽  
Xueping Zhang ◽  
Zhenqiang Yao ◽  
Rajiv Shivpuri
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Titanium Alloys ◽  
Large Scale ◽  
Mechanical Response ◽  
Pure Titanium ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Nano Indentation ◽  
Molecular Dynamics Modeling

Abstract Titanium alloys’ excellent mechanical and physical properties make it the most popular material widely used in aerospace, medical, nuclear and other significant industries. The study of titanium alloys mainly focused on the macroscopic mechanical mechanism. However, very few researches addressed the nanostructure of titanium alloys and its mechanical response in Nano-machining due to the difficulty to perform and characterize nano-machining experiment. Compared with nano-machining, nano-indentation is easier to characterize the microscopic plasticity of titanium alloys. This research presents a nano-indentation molecular dynamics model in titanium to address its microstructure alteration, plastic deformation and other mechanical response at the atomistic scale. Based on the molecular dynamics model, a complete nano-indentation cycle, including the loading and unloading stages, is performed by applying Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The plastic deformation mechanism of nano-indentation of titanium with a rigid diamond ball tip was studied under different indentation velocities. At the same time, the influence of different environment temperatures on the nano-plastic deformation of titanium is analyzed under the condition of constant indentation velocity. The simulation results show that the Young’s modulus of pure titanium calculated based on nano-indentation is about 110GPa, which is very close to the experimental results. The results also show that the mechanical behavior of titanium can be divided into three stages: elastic stage, yield stage and plastic stage during the nano-indentation process. In addition, indentation speed has influence on phase transitions and nucleation of dislocations in the range of 0.1–1.0 Å/ps.

Multilevel Regression and Poststratification Versus Survey Sample Weighting for Estimating Population Quantities in Large Population Health Studies

2020 ◽  
Vol 189 (7) ◽  
pp. 717-725 ◽  
Author(s):  
Marnie Downes ◽  
John B Carlin
Keyword(s):  
Population Health ◽  
Large Scale ◽  
Census Data ◽  
Large Population ◽  
Population Data ◽  
Superior Performance ◽  
Population Parameter ◽  
Multilevel Regression ◽  
Sample Weighting ◽  
Survey Weighting

Abstract Multilevel regression and poststratification (MRP) is a model-based approach for estimating a population parameter of interest, generally from large-scale surveys. It has been shown to be effective in highly selected samples, which is particularly relevant to investigators of large-scale population health and epidemiologic surveys facing increasing difficulties in recruiting representative samples of participants. We aimed to further examine the accuracy and precision of MRP in a context where census data provided reasonable proxies for true population quantities of interest. We considered 2 outcomes from the baseline wave of the Ten to Men study (Australia, 2013–2014) and obtained relevant population data from the 2011 Australian Census. MRP was found to achieve generally superior performance relative to conventional survey weighting methods for the population as a whole and for population subsets of varying sizes. MRP resulted in less variability among estimates across population subsets relative to sample weighting, and there was some evidence of small gains in precision when using MRP, particularly for smaller population subsets. These findings offer further support for MRP as a promising analytical approach for addressing participation bias in the estimation of population descriptive quantities from large-scale health surveys and cohort studies.

Field test of large-scale hydrogen manufacturing from underground coal gasification (UCG)

2008 ◽  
Vol 33 (4) ◽  
pp. 1275-1285 ◽  
Author(s):  
Lanhe Yang ◽  
Xing Zhang ◽  
Shuqin Liu ◽  
Li Yu ◽  
Weilian Zhang
Keyword(s):  
Field Test ◽  
Large Scale ◽  
Coal Gasification ◽  
Underground Coal Gasification

scholarly journals Simulation of Cyclic Loading on Pipe Elbows Using Advanced Plane-Stress Elastoplasticity Models1

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Konstantinos Chatziioannou ◽  
Yuner Huang ◽  
Spyros A. Karamanos
Keyword(s):  
Cyclic Loading ◽  
Large Scale ◽  
Mechanical Response ◽  
Low Cycle Fatigue ◽  
Constitutive Relations ◽  
Cyclic Plasticity ◽  
Integration Scheme ◽  
Repeated Loading ◽  
Finite Element Software ◽  
Hardening Models

Abstract This work investigates the response of industrial steel pipe elbows subjected to severe cyclic loading (e.g., seismic or shutdown/startup conditions), associated with the development of significant inelastic strain amplitudes of alternate sign, which may lead to low-cycle fatigue. To model this response, three cyclic-plasticity hardening models are employed for the numerical analysis of large-scale experiments on elbows reported elsewhere. The constitutive relations of the material model follow the context of von Mises cyclic elasto-plasticity, and the hardening models are implemented in a user subroutine, developed by the authors, which employs a robust numerical integration scheme, and is inserted in a general-purpose finite element software. The three hardening models are evaluated in terms of their ability to predict the strain range at critical locations, and in particular, strain accumulation over the load cycles, a phenomenon called “ratcheting.” The overall good comparison between numerical and experimental results demonstrates that the proposed numerical methodology can be used for simulating accurately the mechanical response of pipe elbows under severe inelastic repeated loading. Finally, this paper highlights some limitations of conventional hardening rules in simulating multi-axial material ratcheting.

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