A one-dimensional creep model for frozen soils taking temperature as an independent variable

A refined theory of axisymmetric cylinder in one-dimensional (1D) hexagonal quasicrystals (QCs) is analyzed. Based on elastic theory with 1D hexagonal QCs, the refined theory of axisymmetric cylinder is derived by using general solution of 1D hexagonal QCs and Lur’e method without ad hoc assumptions. At first, expressions were obtained for all the phonon and phason displacements and stress components in term of the three functions with single independent variable. Based on the boundary conditions, the refined equation for the cylinder is derived directly. And the approximate equation is accurate up to the second-order terms with respect to radius of circular cylinder.

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Revisiting Twomey's approximation for peak supersaturation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-25901-2014 ◽

2014 ◽

Vol 14 (19) ◽

pp. 25901-25930

Author(s):

B. J. Shipway

Keyword(s):

Lookup Table ◽

Accurate Calculation ◽

Cloud Droplets ◽

Closed Expression ◽

One Dimensional ◽

Additional Information ◽

Droplet Nucleation ◽

Physically Based ◽

Thermodynamic Conditions ◽

Independent Variable

Abstract. Twomey's seminal 1959 paper provided lower and upper bound approximations to the estimation of peak supersaturation within an updraft and thus provides the first closed expression for the number of nucleated cloud droplets. The form of this approximation is simple, but provides a surprisingly good estimate and has subsequently been employed in more sophisticated treatments of nucleation parametrization. In the current paper, we revisit the lower bound approximation of Twomey and make a small adjustment which can be used to obtain a more accurate calculation of peak supersaturation under all potential aerosol loadings and thermodynamic conditions. In order to make full use of this improved approximation, the underlying integro-differential equation for supersaturation evolution and the condition for calculating peak supersaturation are examined. A simple rearrangement of the algebra allows for an expression to be written down which can then be solved with a single lookup table with only one independent variable for an underlying lognormal aerosol population. Multimode aerosol with only N different dispersion characteristics require only N of these one-dimensional lookup tables. No additional information is required in the lookup table to deal with additional chemical, physical or thermodynamic properties. The resulting implementation provides a relatively simple, yet computationally cheap and very accurate physically-based parametrization of droplet nucleation for use in climate and NWP models.

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Computational analysis of creep in ice and frozen soil based on Fish's unified model

Canadian Journal of Civil Engineering ◽

10.1139/l93-013 ◽

1993 ◽

Vol 20 (1) ◽

pp. 120-132 ◽

Cited By ~ 4

Author(s):

U. G. A. Puswewala ◽

R. K. N. D. Rajapakse

Keyword(s):

Finite Element ◽

Frozen Soil ◽

Creep Model ◽

Finite Element Code ◽

Creep Tests ◽

Frozen Soils ◽

Uniaxial Creep ◽

Media Interaction ◽

Load Tests ◽

Experimental Findings

The ability of the creep model of Fish to simulate the observed behaviour of ice and frozen soils in multiaxial stress-strain fields is investigated. The generalization of the original uniaxial creep model is made through the use of several assumptions and the multiaxial model is implemented in an iterative, time-incrementing finite element code. Sample creep parameters for the model are evaluated using previously reported uniaxial creep tests on ice and frozen silt. The finite element code is used to demonstrate the ability of the model to predict different stages of creep deformation in frozen media, by re-simulating some uniaxial creep tests on ice. Pressuremeter tests, plate load tests, and laterally loaded rigid cores (piles considered in cross section) in frozen media are simulated to demonstrate the similarity between the global response of ice and frozen soils predicted by the model and the reported experimental findings. Redistribution of stress predicted by the model is also investigated. The model is seen to possess validity in situations of attenuating as well as accelerating creep of ice and frozen soils. Key words: creep, ice, frozen soils, finite elements, structure–frozen media interaction, numerical prediction.

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Thermally and field-driven mobility of emergent magnetic charges in square artificial spin ice

Scientific Reports ◽

10.1038/s41598-019-52460-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Sophie A. Morley ◽

Jose Maria Porro ◽

Aleš Hrabec ◽

Mark C. Rosamond ◽

Diego Alba Venero ◽

...

Keyword(s):

Critical Field ◽

Magnetic Monopoles ◽

Model Systems ◽

Square Lattice ◽

Creep Model ◽

Spin Ice ◽

One Dimensional ◽

X Ray ◽

Drift Motion ◽

Artificial Spin Ice

Abstract Designing and constructing model systems that embody the statistical mechanics of frustration is now possible using nanotechnology. We have arranged nanomagnets on a two-dimensional square lattice to form an artificial spin ice, and studied its fractional excitations, emergent magnetic monopoles, and how they respond to a driving field using X-ray magnetic microscopy. We observe a regime in which the monopole drift velocity is linear in field above a critical field for the onset of motion. The temperature dependence of the critical field can be described by introducing an interaction term into the Bean-Livingston model of field-assisted barrier hopping. By analogy with electrical charge drift motion, we define and measure a monopole mobility that is larger both for higher temperatures and stronger interactions between nanomagnets. The mobility in this linear regime is described by a creep model of zero-dimensional charges moving within a network of quasi-one-dimensional objects.

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Non-autonomous equations related to polynomial two-dimensional systems

Proceedings of the Royal Society of Edinburgh Section A Mathematics ◽

10.1017/s0308210500021971 ◽

1987 ◽

Vol 105 (1) ◽

pp. 129-152 ◽

Cited By ~ 88

Author(s):

M. A. M. Alwash ◽

N. G. Lloyd

Keyword(s):

Differential Equations ◽

Periodic Solutions ◽

Sufficient Conditions ◽

Two Dimensional ◽

One Dimensional ◽

Introductory Section ◽

Independent Variable ◽

Autonomous Differential Equations

SynopsisPeriodic solutions of certain one-dimensional non-autonomous differential equations are investigated (equation (1.4)); the independent variable is complex. The motivation, which is explained in the introductory section, is the connection with certain polynomial two-dimensional systems. Several classes of coefficients are considered; in each case the aim is to estimate the maximum number of periodic solutions into which a given solution can bifurcate under perturbation of the coefficients. In particular, we need to know when there is a full neighbourhood of periodic solutions. We give a number of sufficient conditions and investigate the implications for the corresponding two-dimensional systems.

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Automorphisms of Ordinary Differential Equations

Abstract and Applied Analysis ◽

10.1155/2014/482963 ◽

2014 ◽

Vol 2014 ◽

pp. 1-32 ◽

Cited By ~ 1

Author(s):

Václav Tryhuk ◽

Veronika Chrastinová

Keyword(s):

Differential Equations ◽

Ordinary Differential Equations ◽

Local Theory ◽

Full Generality ◽

One Dimensional ◽

Underdetermined Systems ◽

Dependent Variables ◽

Variational Integrals ◽

Independent Variable ◽

Internal Symmetries

The paper deals with the local theory of internal symmetries of underdetermined systems of ordinary differential equations in full generality. The symmetries need not preserve the choice of the independent variable, the hierarchy of dependent variables, and the order of derivatives. Internal approach to the symmetries of one-dimensional constrained variational integrals is moreover proposed without the use of multipliers.

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A Study on the Creep Characteristics of Airport Viscous Subsoil Based on Unsaturated Stress Level

Geofluids ◽

10.1155/2021/6667245 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Jun Feng ◽

Yue Ma ◽

Zaobao Liu

Keyword(s):

Stress Level ◽

Unsaturated Soil ◽

Three Dimensional ◽

Matric Suction ◽

Creep Model ◽

Creep Stage ◽

One Dimensional ◽

Creep Characteristics ◽

Stress Levels ◽

The One

The present study takes the ratio of the matric suction to the net vertical stress and the ratio of the matric suction to the net mean stress as new unsaturated stress levels f and F , respectively. Based on the laboratory tests and theoretical derivation, the modified one-dimensional Mesri creep model and three-dimensional creep model were established, which takes the unsaturated stress level into account. Then, the one-dimensional and three-dimensional creep characteristics of the unsaturated viscous subsoil of an airport under different unsaturated stress levels were analyzed. The following conclusions could be drawn: (1) under different stress levels, the one-dimensional creep deformation of unsaturated soil has a power function relationship with time, and the change rate exponentially decreases with the stress level, which can be well-expressed by the proposed modified one-dimensional Mesri creep model; (2) under different stress levels, the three-dimensional creep strain of the unsaturated soil shows a hyperbolic curve with time and a near-linear relationship at the semilogarithmic coordinate, which can be well-expressed by the proposed modified three-dimensional creep model; (3) under different stress levels, both the one-dimensional creep and three-dimensional creep of the unsaturated soil can be divided into two stages, which are the accelerated creep stage and stable creep stage.

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The Role of Convective Heat Transport in the Thawing of Frozen Soils

Canadian Geotechnical Journal ◽

10.1139/t75-046 ◽

1975 ◽

Vol 12 (3) ◽

pp. 425-429 ◽

Cited By ~ 33

Author(s):

John F. Nixon

Keyword(s):

Heat Transfer ◽

Convective Heat Transfer ◽

Convective Heat ◽

Mathematical Problem ◽

Practical Interest ◽

Significant Loss ◽

Minor Role ◽

Frozen Soils ◽

One Dimensional ◽

Wide Range

One-dimensional solutions for the rate of thaw in frozen soils often neglect the effects of convective heat transfer in the thawing soil. To the present time, it has been difficult to assess the importance of such effects for thawing soils due to the complexities in obtaining solutions to the mathematical problem. This note describes a solution for a one-dimensional thawing problem of considerable practical interest, which accounts for convective heat transfer caused by the migration of melt water to the soil surface. The solution applies for a wide range of conditions likely to be experienced in the field, and demonstrates the very minor role played by convective heat transfer in determining the rate of thaw. It is encouraging to observe that for most one-dimensional thaw calculations, the effects of convective heat transfer may be neglected without significant loss in accuracy.

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The role of activating work ethic in reducing manifestations of administrative corruption

Journal of University of Human Development ◽

10.21928/juhd.v3n2y2017.pp493-523 ◽

2017 ◽

Vol 3 (2) ◽

pp. 493

Author(s):

Nazima Ahmed Aljaf ◽

Zana Majeed Sadq ◽

Ryam Salah Hassan

Keyword(s):

Work Ethic ◽

Secondary Data ◽

Administrative Leadership ◽

University Management ◽

One Dimensional ◽

Independent Variable ◽

The Impact ◽

Impact Hypothesis ◽

Study Hypothesis

This study seeks to activate the job carrier ethic in curbing the phenomenon of administrative corruption. To achieve the objectives of this study secondary data collected to clarify the concepts of both job carrier ethic and administrative corruption. In addition to design and development a survey questionnaire distributed to the administrative leadership of deans and their assistants as well as the heads of scientific departments at Koya University Kurdistan Region –Iraq. The study problem embodied in a basis question that: What is the role of job carrier ethic in the reduction of administrative corruption and its demonstration in the view of the respondents. Two main hypotheses will be tested: Correlation hypothesis: there is a statistically significant correlation between the activation of job carrier ethic in reducing the phenomenon of administrative corruption. 2. Impact hypothesis: There is a significant impact of job carrier ethic on reducing the phenomenon of administrative corruption. SPSS program used along with a range of statistical methods for the purposes of analyzing the questionnaire items including percentages and frequency to analyze the respondent's answers of paragraphs contained in the questionnaire. In order to testing the study hypothesis, the study will rely on the correlation coefficient (Pearson) to test the correlation between study variables. Moreover, multiple regression analysis will be used to determine the impact of the independent variable (job carrier ethic) on dependent variable (administrative corruption). The study found that there is a positive correlation and an impact between activate the job carrier ethic in curbing the phenomenon of administrative corruption. Based on the above, this study recommends the necessitate of university management to work to make greater efforts to infuse the concept of ethics career as one-dimensional organizational and regulatory environment appropriate to provide the personnel as well as introduce the concept of career work ethic in institutes and universities within their curricula independent in the years of the study.

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