scholarly journals Experimental testing of the new flow equation of cement dispersion

2009 ◽  
Vol 4 (1) ◽  
pp. 051-062
Author(s):  
Jerzy Szerafin
Keyword(s):  
Theoretical Model ◽  
Experimental Research ◽  
Main Part ◽  
Experimental Testing ◽  
Flow Equation ◽  
Flow Equations ◽  
Practical Applications ◽  
Flow Through ◽  
New Equation ◽  
Annular Pipe

The new flow equation of cement dispersion included factor of the friction between cement grains is presented in the paper. The analysis of the calculation’s results confirms the property of new equation. In the main part of the paper the results of experimental research were presented. The first part of research applies to cement flow through annular pipe, which exactly matches the theoretical model assumptions. The second part of flow tests was carried out in aggregate pile, which is typical to many practical applications of cement injection. Calculation and experimental test’s results are compatible and proof the correctness of new flow equations.

scholarly journals Groundwater flow equation, overview, derivation, and solution

2021 ◽  
Vol 314 ◽  
pp. 04007
Author(s):  
Lhoussaine El Mezouary ◽  
Bouabid El Mansouri
Keyword(s):  
Heat Transfer ◽  
Differential Equation ◽  
Groundwater Flow ◽  
Numerical Solutions ◽  
Flow Equation ◽  
Heat Transfer Equation ◽  
Flow Equations ◽  
Basic Law ◽  
Flow Through ◽  
Groundwater Flow Equation

Darcy’s law is the basic law of flow, and it produces a partial differential equation is similar to the heat transfer equation when coupled with an equation of continuity that explains the conservation of fluid mass during flow through a porous media. This article, titled the groundwater flow equation, covers the derivation of the groundwater flow equations in both the steady and transient states. We look at some of the most common approaches and methods for developing analytical or numerical solutions. The flaws and limits of these solutions in reproducing the behavior of water flow on the aquifer are also discussed in the article.

scholarly journals Influence of the friction factor on the range of cement dispersion flow

2008 ◽  
Vol 2 (1) ◽  
pp. 141-153
Author(s):  
Jerzy Szerafin
Keyword(s):  
Friction Factor ◽  
Cement Paste ◽  
Flow Equation ◽  
Bingham Model ◽  
Rheological Models ◽  
The Real ◽  
Practical Applications ◽  
Injection Process ◽  
New Equation ◽  
Continuous Material

Dispersial nature of cement grout makes many difficulties in practical applications of the injection process. It is also difficult to describe by theoretical equations. The rheological models treat cement paste as continuous material. In this paper the new flow equation was derived, which contains the factor of the friction between cement grains introduced to the Bingham model. The possibilities of the calculation of this new factor was presented. The analysis of the calculation’s results of the classical and new equations shows significant differences. The new equation allows to better predict the effects of the real injection applications.

scholarly journals Negative and positive stiffness in auxetic magneto-mechanical metamaterials

2018 ◽  
Vol 474 (2215) ◽  
pp. 20180003 ◽  
Author(s):  
K. K. Dudek ◽  
R. Gatt ◽  
M. R. Dudek ◽  
J. N. Grima
Keyword(s):  
Theoretical Model ◽  
Experimental Testing ◽  
Vibration Damping ◽  
Negative Stiffness ◽  
Poisson's Ratio ◽  
Fundamental Importance ◽  
Practical Applications ◽  
Mechanical Metamaterials ◽  
Wide Range ◽  
Negative Poisson's Ratio

This work discusses the concept of allowing the control of the stiffness of a particular class of re-entrant auxetic magneto-mechanical metamaterials through the introduction of magnets to the system. It is shown, through experimental testing backed up by a theoretical model, that the appropriate insertion of magnets in such a system will alter its stiffness, possibly even making it exhibit ‘negative stiffness’. This leads to a completely different behaviour of the structure in terms of stability. It is also reported that the investigated mechanical metamaterials may exhibit both negative stiffness and negative Poisson's ratio at the same time. Moreover, it is shown that the effect which magnets have on the stiffness of the system may be fine-tuned upon replacing magnets with electromagnets. Such systems have the potential to be used in a wide range of practical applications such as vibration damping devices where achieving a negative stiffness is of fundamental importance.

Selection and application of a one-dimensional non-Darcy flow equation for two-dimensional flow through rockfill embankments

1995 ◽  
Vol 32 (2) ◽  
pp. 223-232 ◽  
Author(s):  
David Hansen ◽  
Vinod K. Garga ◽  
D. Ronald Townsend
Keyword(s):  
Packed Column ◽  
Flow Equation ◽  
Hydraulic Gradient ◽  
Darcy Flow ◽  
Two Dimensional ◽  
Rating Curve ◽  
One Dimensional ◽  
Flow Equations ◽  
Flow Through ◽  
Hydraulics Laboratory

Porous embankments comprised of relatively homogeneous coarse rockfill can be used to reduce the amount of spillage at downstream hydro dams or to control the outflow from stormwater detention basins. The stage-discharge rating curve is important in the design of such applications. In general, the coarseness of the material causes the flow to be non-Darcy; that is, characterized by a nonlinear relationship between bulk velocity and hydraulic gradient. Six one-dimensional (1D) non-Darcy flow equations, appearing in the literature, are presented. A limited comparison between computed and experimental results is then made on the basis of 1D packed-column tests performed in the hydraulics laboratory of the University of Ottawa. The question as to how such 1D closed-conduit equations might be used to estimate the quantity of flow through a porous embankment is then addressed, considering that the latter has a free surface and is a two-dimensional (2D) flow. The problem is successfully dealt with using the concept of "effective hydraulic gradient," a concept reminiscent of the method of sections used to analyze confined 2D seepage problems. A general equation is presented in which the effective hydraulic gradient is shown to be a function of two factors: (1) the shape of the embankment and (2) the upstream depth, relative to the height of the dam. The development and verification of the equation for the effective hydraulic gradient is described, together with its use in obtaining a rating curve for a hypothetical flowthrough dam composed of rock material 0.25 m in diameter. Key words : non-Darcy flow, flowthrough rockfill, effective hydraulic gradient, stage-discharge rating curve.

scholarly journals Relating a Rate-Independent System and a Gradient System for the Case of One-Homogeneous Potentials

2021 ◽  
Author(s):  
Alexander Mielke
Keyword(s):  
Gradient Flow ◽  
Careful Analysis ◽  
Flow Equation ◽  
Uniqueness Result ◽  
Gradient System ◽  
Independent System ◽  
Exact Relation ◽  
Flow Equations ◽  
Total Variation Flow ◽  
Energetic Solutions

AbstractWe consider a non-negative and one-homogeneous energy functional $${{\mathcal {J}}}$$ J on a Hilbert space. The paper provides an exact relation between the solutions of the associated gradient-flow equations and the energetic solutions generated via the rate-independent system given in terms of the time-dependent functional $${{\mathcal {E}}}(t,u)= t {{\mathcal {J}}}(u)$$ E ( t , u ) = t J ( u ) and the norm as a dissipation distance. The relation between the two flows is given via a solution-dependent reparametrization of time that can be guessed from the homogeneities of energy and dissipations in the two equations. We provide several examples including the total-variation flow and show that equivalence of the two systems through a solution dependent reparametrization of the time. Making the relation mathematically rigorous includes a careful analysis of the jumps in energetic solutions which correspond to constant-speed intervals for the solutions of the gradient-flow equation. As a major result we obtain a non-trivial existence and uniqueness result for the energetic rate-independent system.

Heat Compensation in Buildings Using Thermoelectric Windows: An Energy Efficient Window Technology

2008 ◽  
Author(s):  
Rhys-Sheffer Birthwright ◽  
Achille Messac ◽  
Timothy Harren-Lewis ◽  
Sirisha Rangavajhala
Keyword(s):  
Energy Efficient ◽  
Coefficient Of Performance ◽  
Building Structures ◽  
Practical Applications ◽  
Current Input ◽  
Flow Through ◽  
Conventional Systems ◽  
Window Design ◽  
Absorption Power ◽  
Do So

In this paper, we explore the design of thermoelectric (TE) windows for applications in building structures. Thermoelectric windows are equipped with TE units in the window frame to provide a heat absorption power, given a direct current input. We explore the design performance of the TE window to compensate for its own heat gains. While existing energy efficient windows have made advances towards reducing the heat transfer through them, they still depend on the building’s heating, ventilation and air-conditioning (HVAC) system to compensate for their heat gains. Our research explores the design of a window that can actively compensate for the passive heat flow through the window panes, and to do so with a better coefficient of performance (COP) than conventional HVAC systems. We also optimize the TE window design, and present results of the potential performance for practical applications in the building structure. For the geographic locations considered (Hawaii and Miami), the results are promising. Interestingly, the proposed TE window design actively compensates for the conduction heat gains with a COP greater than three, while that of conventional systems is typically less than three.

A Novel Infinite-Acting-Radial-Flow Analysis Procedure for Estimating Permeability Anisotropy From an Observation-Probe Pressure Response at a Vertical, Horizontal, or Inclined Wellbore

2014 ◽  
Vol 17 (02) ◽  
pp. 152-164 ◽  
Author(s):  
M.. Onur ◽  
P.S.. S. Hegeman ◽  
I.M.. M. Gök
Keyword(s):  
Radial Flow ◽  
Flow Analysis ◽  
Single Layer ◽  
Flow Equation ◽  
Observation Point ◽  
Analysis Procedure ◽  
Pressure Transient ◽  
Flow Equations ◽  
Vertical Permeability ◽  
Inclination Angles

Summary This paper presents a new infinite-acting-radial-flow (IARF) analysis procedure for estimating horizontal and vertical permeability solely from pressure-transient data acquired at an observation probe during an interval pressure-transient test (IPTT) conducted with a single-probe, dual-probe, or dual-packer module. The procedure is based on new infinite-acting-radial-flow equations that apply for all inclination angles of the wellbore in a single-layer, 3D anisotropic, homogeneous porous medium. The equations for 2D anisotropic cases are also presented and are derived from the general equations given for the 3D anisotropic case. It is shown that the radial-flow equation presented reduces to Prats' (1970) equation assuming infinite-acting radial flow at an observation point along a vertical wellbore in isotropic or 2D anisotropic formations of finite bed thickness. The applicability of the analysis procedure is demonstrated by considering synthetic and field packer/probe IPTT data. The synthetic IPTT examples include horizontal- and slanted-well cases, but the field IPTT is for a vertical well. The results indicate that the procedure provides reliable estimates of horizontal and vertical permeability solely from observation-probe pressure data during radial flow for vertical, horizontal, and inclined wellbores. Most importantly, the analysis does not require that both spherical and radial flow prevail at the observation probe during the test.

scholarly journals GenC: A Fast Tool for Applications Involving Belief Revision

2020 ◽  
Author(s):  
Aaron Hunter ◽  
John Agapeyev
Keyword(s):  
Theoretical Model ◽  
Parallel Processing ◽  
Incomplete Information ◽  
Belief Revision ◽  
Hamming Distance ◽  
Difference Operators ◽  
Practical Applications ◽  
Reasoning System ◽  
Extensive Class

The process of belief revision occurs in many applications where agents may have incorrect or incomplete information. One important theoretical model of belief revision is the well-known AGM approach. Unfortunately, there are few tools available for solving AGM revision problems quickly; this has limited the use of AGM operators for practical applications. In this demonstration paper, we describe GenC, a tool that is able to quickly calculate the result of AGM belief revision for formulas with hundreds of variables and millions of clauses. GenC uses an AllSAT solver and parallel processing to solve revision problems at a rate much faster than existing systems. The solver works for the class of parametrised difference operators, which is an extensive class of revision operators that use a weighted Hamming distance to measure the similarity between states. We demonstrate how GenC can be used as a stand-alone tool or as a component of a reasoning system for a variety of applications.

Experimental research on the performance of nanofluid flow through conically coiled tubes

2020 ◽  
Vol 370 ◽  
pp. 268-277 ◽  
Author(s):  
M.M. Heyhat ◽  
A. Jafarzad ◽  
P. Changizi ◽  
H. Asgari ◽  
M. Valizade
Keyword(s):  
Experimental Research ◽  
Nanofluid Flow ◽  
Flow Through

scholarly journals Frontier Progress of Unmanned Aerial Vehicles Optical Wireless Technologies

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5476
Author(s):  
Jupeng Ding ◽  
Hongye Mei ◽  
Chih-Lin I ◽  
Hui Zhang ◽  
Wenwen Liu
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Transmission Rate ◽  
Experimental Testing ◽  
High Reliability ◽  
Communication Link ◽  
Optical Wireless ◽  
Wireless Technology ◽  
Technical Problems ◽  
Practical Applications ◽  
Aerial Vehicles

With the continuous maturity of unmanned aerial vehicles (UAV) in materials, communications, and other related technologies, the UAV industry has developed rapidly in recent years. In order to cope with the diversified emerging business forms, the explosive growth of the scale of data traffic, number of terminal connections, high reliability, low-latency, and high transmission rate provided by the fifth generation (5G) network will inject new vitality into the development of the UAVs industry. In this paper, optical wireless technology is introduced into the UAV platform, combining theory with practical applications. We explain many research advances and key technologies in the four aspects of “air, space, earth, and sea” to achieve a strong and broadband communication link. This discussion focuses on link modeling, parameter optimization, experimental testing, and the status quo of UAVs in different application scenarios with optical wireless link configurations. At the same time, based on the current situation of UAV optical wireless technology, the technical problems and the research direction in the future are also discussed.

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