Response analysis of subgrade soils using signal phase shift obtained from laboratory lightweight deflectometer tests

Author(s):  
Jean-Pascal Bilodeau ◽  
Mbayang Kandji ◽  
Mai Lan Nguyen

Over the past decades, the use of fast and reliable measurement techniques of soil mechanical properties has gained popularity. The lightweight deflectometer (LWD) is among the tools developed that can allow one to determine the elastic modulus of soil. Viscosity response components in pavement or soil typically induce phase shifts between stress and strain peaks, which can be translated to phase angle. Subgrade soil may exhibit varying response types depending on its nature and characteristics. Using large laboratory subgrade samples, an experiment was designed to measure the elastic modulus and phase angle with an LWD in different stress and humidity conditions. A model associating the elastic modulus inferred from LWD tests with parameters describing stress, water content and soil properties was proposed. This model is fundamentally inferred from the relationship between elastic modulus and phase shift, and was used to assess the relative contribution of varying conditions on soil stiffness.

2011 ◽  
Vol 255-260 ◽  
pp. 1171-1175 ◽  
Author(s):  
Han Bing Liu ◽  
Jing Wang ◽  
Chun Li Wu ◽  
Kai Feng

Three kinds of subgrade soils with different plasticity index are selected from seasonally frozen soil region. Frost heaving ratio of volume and height was performed on the samples exposed to 0 to 8 times closed-system freeze-thaw cycles. The results show that concerning the same kind of soil, the frost heaving ratio increases with the number of freeze-thaw cycles; Frost heaving ratio increases with plasticity index under the same number of freeze-thaw cycles. Multiple nonlinear fitting is adopted for test data. The relationship between frost heaving ratio and plasticity index, freeze-thaw cycles is obtained and shows a good correlation. The relation can provide useful reference for subgrade design and construction in seasonally frozen soil region.


2019 ◽  
Vol 22 (3) ◽  
pp. 365-380 ◽  
Author(s):  
Matthias Olthaar ◽  
Wilfred Dolfsma ◽  
Clemens Lutz ◽  
Florian Noseleit

In a competitive business environment at the Bottom of the Pyramid smallholders supplying global value chains may be thought to be at the whims of downstream large-scale players and local market forces, leaving no room for strategic entrepreneurial behavior. In such a context we test the relationship between the use of strategic resources and firm performance. We adopt the Resource Based Theory and show that seemingly homogenous smallholders deploy resources differently and, consequently, some do outperform others. We argue that the ‘resource-based theory’ results in a more fine-grained understanding of smallholder performance than approaches generally applied in agricultural economics. We develop a mixed-method approach that allows one to pinpoint relevant, industry-specific resources, and allows for empirical identification of the relative contribution of each resource to competitive advantage. The results show that proper use of quality labor, storage facilities, time of selling, and availability of animals are key capabilities.


1999 ◽  
Vol 07 (02) ◽  
pp. 113-130 ◽  
Author(s):  
I. M. DE LA FUENTE ◽  
L. MARTINEZ ◽  
J. M. AGUIRREGABIRIA ◽  
J. VEGUILLAS ◽  
M. IRIARTE

In biochemical dynamical systems during each transition between periodical behaviors, all metabolic intermediaries of the system oscillate with the same frequency but with different phase-shifts. We have studied the behavior of phase-shift records obtained from random transitions between periodic solutions of a biochemical dynamical system. The phase-shift data were analyzed by means of Hurst's rescaled range method (introduced by Mandelbrot and Wallis). The results show the existence of persistent behavior: each value of the phase-shift depends not only on the recent transitions, but also on previous ones. In this paper, the different kind of periodic solutions were determined by different small values of the control parameter. It was assessed the significance of this results through extensive Monte Carlo simulations as well as quantifying the long-range correlations. We have also applied this type of analysis on cardiac rhythms, showing a clear persistent behavior. The relationship of the results with the cellular persistence phenomena conditioned by the past, widely evidenced in experimental observations, is discussed.


2021 ◽  
Vol 13 (11) ◽  
pp. 6221
Author(s):  
Muyuan Ma ◽  
Yaojun Zhu ◽  
Yuanyun Wei ◽  
Nana Zhao

To predict the consequences of environmental change on the biodiversity of alpine wetlands, it is necessary to understand the relationship between soil properties and vegetation biodiversity. In this study, we investigated spatial patterns of aboveground vegetation biomass, cover, species diversity, and their relationships with soil properties in the alpine wetlands of the Gannan Tibetan Autonomous Prefecture of on the Qinghai-Tibetan Plateau, China. Furthermore, the relative contribution of soil properties to vegetation biomass, cover, and species diversity were compared using principal component analysis and multiple regression analysis. Generally, the relationship between plant biomass, coverage, diversity, and soil nutrients was linear or unimodal. Soil pH, bulk density and organic carbon were also significantly correlated to plant diversity. The soil attributes differed in their relative contribution to changes in plant productivity and diversity. pH had the highest contribution to vegetation biomass and species richness, while total nitrogen was the highest contributor to vegetation cover and nitrogen–phosphorus ratio (N:P) was the highest contributor to diversity. Both vegetation productivity and diversity were closely related to soil properties, and soil pH and the N:P ratio play particularly important roles in wetland vegetation biomass, cover, and diversity.


1988 ◽  
Vol 91 (5) ◽  
pp. 703-723 ◽  
Author(s):  
M Mizunami ◽  
H Tateda

The relationship between the slow potential and spikes of second-order ocellar neurons of the cockroach, Periplaneta americana, was studied. The stimulus was a sinusoidally modulated light with various mean illuminances. A solitary spike was generated at the depolarizing phase of the modulation response. Analysis of the relationship between the amplitude/frequency of voltage modulation and the rate of spike generation showed that (a) the spike initiation process was bandpass at approximately 0.5-5 Hz, (b) the process contained a dynamic linearity and a static nonlinearity, and (c) the spike threshold at optimal frequencies (0.5-5 Hz) remained unchanged over a mean illuminance range of 3.6 log units, whereas (d) the spike threshold at frequencies of less than 0.5 Hz was lower at a dimmer mean illuminance. The voltage noise in the response was larger and the mean membrane potential level was more positive at a dimmer mean illuminance. Steady or noise current injection during sinusoidal light stimulation showed that (a) the decrease in the spike threshold at a dimmer mean illuminance was due to the increase in the noise variance: the noise had facilitatory effects on the spike initiation; and (b) the change in the mean potential level had little effect on the spike threshold. We conclude that fundamental signal modifications occur during the spike initiation in the cockroach ocellar neuron, a finding that differs from the spike initiation process in other visual systems, including Limulus eye and vertebrate retina, in which it is presumed that little signal modification occurs at the analog-to-digital conversion process.


2005 ◽  
Vol 2 (2) ◽  
pp. 173-180
Author(s):  
Zlata Cvetkovic ◽  
Slavoljub Aleksic ◽  
Bojana Nikolic

Transients on a loss less exponential transmission line with a pure resistance load are presented in this paper. The approach is based on the two-port presentation of the transmission line. Using Picard-Carson's method the transmission line equations are solved. The relationship between source voltage and the load voltage in s-domain is derived. All the results are plotted using program package Mathematica 3.0.


2019 ◽  
Vol 2 (1) ◽  
pp. 36
Author(s):  
Jack suman Rulis Manurung

The purpose of this research is to find out: 1) The relationship of leg muscle strength to the results of shooting the silent ball towards the goal. 2) Relationship between ankle coordination and the result of shooting the ball silently towards the goal. 3) The relationship between leg muscle strength and ankle coordination towards the results of shooting the ball silently towards the goal.The method used in this study is a method of correlation with test and measurement techniques. Data analysis was carried out by a computerized system with simple or multiple regression analysis. The population in this study were students who participated in extra-curricular football at Pontianak's N 8 High School, totaling 22 people. In this study, there was no sampling technique because it took all the population who participated in 22 extra-curricular activities.The results of the analysis of the data obtained indicate that: 1) There is a relationship between leg muscle strength to the results of shooting the silent ball towards the goal. 2) There is a coordination relationship between the ankles and the result of shooting the silent ball towards the goal. 3) There is a relationship between leg muscle strength and ankle coordination towards the results of shooting the silent ball towards the goal.The amount of donation given by leg muscle strength to the results of silent ball shooting towards the goal was 52.1%, while the coordination contribution of the ankle to the results of silent ball shooting towards the goal was 25.3%. While the magnitude of the contribution given by the two variables, namely leg muscle strength and ankle coordination was 59% of the results of shooting the silent ball towards the goal. It is recommended that in addition to practicing silent ball shooting techniques towards the goal, leg muscle strength should be taken into consideration for the trainer in giving a portion of training.


Author(s):  
Junran Ma

With the development of economy, environmental problems gradually outstanding in China. This article adopts the method of empirical study, have collected the data of China's industrial added value, per capita GDP and emissions of the three major pollutants from 2004 to 2015. The VAR model was established on the basis of the logarithm values of the three factors mentioned above, so as to conduct impulse- response analysis to discuss the relationship between industrialization level, economic development and environmental pollution. The conclusion is as follows: (1) At present, the increase of China's industrial added value can promote the decline of China's environmental pollution emissions to a certain extent; (2) China is now at the left of the turning point of the Environmental Kuznets Curve, and the increase of per capita GDP will aggravate environmental pollution.


2011 ◽  
Vol 11 (3) ◽  
pp. 10087-10120 ◽  
Author(s):  
A. M. Batenburg ◽  
S. Walter ◽  
G. Pieterse ◽  
I. Levin ◽  
M. Schmidt ◽  
...  

Abstract. Despite the potential of isotope measurements to improve our understanding of the global atmospheric molecular hydrogen (H2) cycle, few H2 isotope data have been published so far. Now, within the EUROpean network for atmospheric HYDRogen Observations and Studies project (EUROHYDROS), weekly to monthly air samples from six locations in a global sampling network have been analysed for hydrogen mixing ratio (m(H2)) and the stable hydrogen isotopic composition of H2 (δ(D,H2), hereafter referred to as δ(D)). The time series thus obtained now cover one to five years for all stations. This is the largest set of ground station observations of δ(D) so far. Annual average δ(D) values are higher at the Southern Hemisphere (SH) than at the Northern Hemisphere (NH) stations; the maximum is observed at Neumayer (Antarctica), and the minimum at the NH midlatitude or subtropical stations. The maximum seasonal differences in δ(D) range from ≈18‰ at Neumayer to ≈45‰ at Schauinsland (Southern Germany); in general, seasonal variability is largest at the NH stations. The timing of minima and maxima differs per station as well. In Alert (Arctic Canada), the variations in δ(D) and m(H2) can be approximated as simple harmonic functions with a ≈5-month phase shift. This out-of-phase seasonal behaviour of δ(D) and m(H2) can also be detected, but with a ≈6-month phase shift, at Mace Head and Cape Verde. However, no seasonal δ(D) cycle could be observed at Schauinsland, which likely reflects the larger influence of local sources and sinks at this continental station. At the two SH stations, no seasonal cycle could be detected in the δ(D) data. Assuming that the sink processes are the main drivers of the observed seasonality in m(H2) and δ(D) on the NH, the relative seasonal variations can be used to estimate the relative sink strength of the two major sinks, deposition to soils and atmospheric oxidation by the hydroxyl (OH) radical. For the NH coastal and marine stations this analysis shows that the relative contribution of soil uptake to the total sink processes increases with latitude.


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