scholarly journals Soil Injection Technology Using an Expandable Polyurethane Resin: A Review

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3666
Author(s):  
Mohanad Muayad Sabri Sabri ◽  
Nikolai Ivanovich Vatin ◽  
Kifayah Abood Mohammed Alsaffar
Keyword(s):  
Finite Element Models ◽  
Existing Buildings ◽  
Complete Understanding ◽  
Theoretical Understanding ◽  
Practical Applications ◽  
Injection Process ◽  
Polyurethane Resin ◽  
Strength And Stiffness ◽  
Injection Technology ◽  
Unique Potential

The soil injection, using an expandable polyurethane resin, holds a unique potential for settlement compensation, lifting, and strengthening the foundations of existing buildings and structures. Although various research and case studies regarding this technology have been published, these studies emphasized the technology’s effectiveness in the rapid lifting process. Nevertheless, there is no complete understanding of the technology, yet, that gathers necessary data leading to a better recognition for this technology in the theoretical understanding and the practical applications. This article aims to provide a comprehensive understanding of this technology. The injection process, the resin’s mechanism, and actual propagation in the soil’s massive, the modified physic-mechanical properties of the soil, the expansion process, the consumption of the resin, and the durability are extensively reviewed in this article. Besides that, this article aims to demonstrate the advantages and limitations of this technology in practical applications. The review also explores the existing finite element models used to calculate the strength and stiffness parameters, evaluating the bearing capacity of the composite (soil-resin) and the settlement after the injection process.

A Framework to Evaluate the Benefit of Seismic Upgrading

2019 ◽  
Vol 35 (2) ◽  
pp. 1045-1051 ◽  
Author(s):  
Clotaire Michel ◽  
Blaise Duvernay ◽  
Ehrfried Kölz ◽  
Navid Jamali ◽  
Pierino Lestuzzi
Keyword(s):  
Existing Buildings ◽  
Design Code ◽  
Absolute Level ◽  
Safety Level ◽  
Seismic Code ◽  
Practical Applications ◽  
The Absolute ◽  
Cost Efficient ◽  
The One ◽  
Level Of Risk

The framework to evaluate the benefit of seismic upgrading of Galanis et al. (2018) is compared to that present in the Swiss seismic code for existing buildings since 2004, updated in 2017. To illustrate the comparison, the example building of Galanis et al. (2018) in Zurich is analyzed following the Swiss code. It is shown that the concept of Degree of Seismic Upgrade is not relevant for practical applications. More generally, the approach of Galanis et al. (2018) would be more suited to a risk-based framework (like the Swiss code) than to a performance-based framework like the one they followed. For existing buildings, we claim that it is appropriate to define the retrofitting strategy based on the absolute level of risk, whereas targeting the safety level of the design code is rarely cost-efficient.

Fabrication of Ultra Low-Density Binderless Sandwiching Materials by Rapid Steam Injection

2016 ◽  
Vol 852 ◽  
pp. 1482-1487
Author(s):  
Fan Cheng ◽  
Yu Hao Jiang ◽  
Jin Bo Chen ◽  
Peng Bo Lu ◽  
Ling Feng Su ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Sound Absorption ◽  
Building Materials ◽  
Bending Strength ◽  
Injection Pressure ◽  
Steam Injection ◽  
Low Density ◽  
Absorption Property ◽  
Injection Process ◽  
Injection Technology

Eco-friendly building materials with perfect thermal insulation & sound absorption property have become intriguing and eye-catching in recent years. In this work, the ultra low-density binderless sandwiching materials were firstly fabricated with ultra low-density of 60-80 kg/m3 by self-designed rapid steam injection technology. The main experimental factor of density, holding time, transmission time, steam injection pressure and fiber’s dimension was respectively investigated to their effects on formation of the new building materials. IR, Py GC-MS and AFM analysis were performed to study the mechanism of binderless sandwiching materials under steam injection process. The bending strength, thermal insulation & sound absorption property of the new materials were also studied. This new building material with no resin use and no formaldehyde release is expected to be reserved as the sandwich for designing thermal insulation & noise reduction building materials.

Numerical Analysis and Mechanical Properties of Nomex™ Honeycomb Core

2017 ◽  
Author(s):  
Yue Liu ◽  
Weicheng Gao ◽  
Wei Liu ◽  
Zhou Hua
Keyword(s):  
Compressive Strength ◽  
Cell Walls ◽  
Mechanical Response ◽  
Compressive Loading ◽  
Fe Model ◽  
Honeycomb Core ◽  
Practical Applications ◽  
Honeycomb Sandwich ◽  
Nomex Honeycomb ◽  
Strength And Stiffness

This paper presents an investigation on the mechanical response of the Nomex honeycomb core subjected to flatwise compressive loading. Thin plate elastic in-plane compressive buckling theory is used to analyze the Nomex honeycomb core cell wall. A mesoscopic finite element (FE) model of honeycomb sandwich structure with the Nomex honeycomb cell walls is established by employing ABAQUS/Explicit shell elements. The compressive strength and compressive stiffness of Nomex honeycomb core with different heights and thickness of cell walls, i.e. double cell walls and single cell walls, are analyzed numerically using the FE model. Flatwise compressive tests are also carried out on bare honeycomb cores to validate the numerical method. The results suggest that the compressive strength and compression stiffness are related to the geometric dimensions of the honeycomb core. The Nomex honeycomb core with a height of 6 mm has a higher strength than that of 8 mm. In addition, the honeycomb core with lower height possesses stronger anti-instability ability, including the compressive strength and stiffness. The proposed mesoscopic model can effectively simulate the crushing process of Nomex honeycomb core and accurately predict the strength and stiffness of honeycomb sandwich panels. Our work is instructive to the practical applications in engineering.

scholarly journals Bistable composite helices with thermal effects

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190295 ◽  
Author(s):  
Seán Carey ◽  
Robert Telford ◽  
Vincenzo Oliveri ◽  
Ciaran McHale ◽  
Paul Weaver
Keyword(s):  
Thermal Effects ◽  
Design Space ◽  
Analytical Description ◽  
Analytical Models ◽  
Fatigue Properties ◽  
Finite Element Models ◽  
Helical Structures ◽  
Industrial Sectors ◽  
Strength And Stiffness ◽  
Increased Strength

Morphing technologies use large, seamless changes in the shape of a structure to enable multi-functionality and reconfigurability. Several industrial sectors could benefit from morphing structures, including medical, energy and aerospace which require lightweight, simple and reliable solutions. Composite materials are key to lightweight morphing technologies due to their increased strength- and stiffness-to-mass ratios, stiffness tailorability and excellent fatigue properties, all of which reduce the mass and complexity of these types of structures. By accounting for thermal effects in their analytical description, we enhance the viability of multi-stable composite helical structures. This consideration improves predictions of existing analytical models in comparison with experiments, while also vastly expanding the design space to include antisymmetric and non-symmetric flange lay-up sequences. The developed analytical model is presented and verified using both finite-element models and experiments. By including thermal effects, we show that beneficial new morphing behaviours can be obtained.

scholarly journals Application of Cross-Hole Tomography for Assessment of Soil Stabilization by Grout Injection

Geosciences ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 399 ◽  
Author(s):  
Mikhail Lebedev ◽  
Kirill Dorokhin
Keyword(s):  
Seismic Tomography ◽  
Urban Areas ◽  
Soil Stabilization ◽  
Geophysical Methods ◽  
Negative Influence ◽  
Actual State ◽  
Existing Buildings ◽  
Practical Applications ◽  
Geotechnical Monitoring ◽  
Urban Conditions

Currently, the spread of megalopolises poses an ever-increasing necessity for underground space development for the purpose of the arrangement of transport communications, underground parking areas, trade areas, etc. The implementation of such projects entails a significant increase in the risk of accidents and damage to existing buildings within construction activity influence areas. The reduction of the risk of accidents during the construction of underground facilities within urban areas may only become possible with the identification of adverse factors negatively influencing existing buildings or a facility under erection and elaboration (to reduce such negative influence). The application of geophysical methods in complex assessments of the actual state of an encompassing mass significantly increases efficiency and the credibility of geotechnical monitoring. The application of seismic tomography significantly increases the resolution capability of surveys. Existing techniques, e.g., seismic tomography, allow for any depths to be investigated at a high resolution, even given constricted urban conditions. This article covers the practical applications of seismic tomography in qualitative assessments of actions and an efficiency evaluation of the injective stabilization of soil.

A Combined Analytical and Numerical Approach to Analyze Mud Motor Excited Vibrations in Drilling Systems

2015 ◽  
Author(s):  
Andreas Hohl ◽  
Carsten Hohl ◽  
Christian Herbig
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Field Measurements ◽  
Element Model ◽  
Numerical Approach ◽  
Analytical Models ◽  
Finite Element Models ◽  
Beam Model ◽  
Direct Influence ◽  
Practical Applications

Severe vibrations in drillstrings and bottomhole assemblies can be caused by cutting forces at the bit or mass imbalances in downhole tools. One of the largest imbalances is related to the working principle of the so-called mud motor, which is an assembly of a rotor that is maintained by the stator. One of the design-related problems is how to minimize vibrations excited by the mud motor. Simulation tools using specialized finite element methods (FEM) are established to model the mechanical behavior of the structure. Although finite element models are useful for estimating rotor dynamic behavior and dynamic stresses of entire drilling systems they do not give direct insight how parameters affect amplitudes and stresses. Analytical models show the direct influence of parameters and give qualitative solutions of design related decisions. However these models do not provide quantitative numbers for complicated geometries. An analytical beam model of the mud motor is derived to calculate the vibrational amplitudes and capture basic dynamic effects. The model shows the direct influence of parameters of the mud motor related to the geometry, material properties and fluid properties. The analytical model is compared to the corresponding finite element model. Vibrational amplitudes are discussed for different modes and parameter changes. Finite element models of the entire drilling system are used to verify the findings from the analytical model using practical applications. The results are compared to time domain and statistical data from laboratory and field measurements.

scholarly journals A resource for introducing molecular modelling into the undergraduate chemistry curriculum

2006 ◽  
pp. 45-46
Author(s):  
Patrick J O’Malley
Keyword(s):  
Computational Methods ◽  
Molecular Modelling ◽  
Theoretical Aspect ◽  
Chemistry Curriculum ◽  
Theoretical Understanding ◽  
Nmr Spectrum ◽  
Undergraduate Level ◽  
Practical Applications ◽  
Undergraduate Chemistry ◽  
Deep Appreciation

Computational methods including molecular modelling are becoming an essential aspect of chemistry. As such there is a pressing need to introduce this methodology at the undergraduate level. In this communication we give our experience of developing an appropriate course using formal lectures and practical workshop sessions. The emphasis is on practical applications. While the essential background theoretical aspect is introduced it is recognised that overemphasis and reliance on theoretical understanding can discourage many students. Our approach is to treat molecular modelling similarly to spectroscopic interpretation where an intelligent interpretation of an NMR spectrum does not always require a deep appreciation of background NMR theory.

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.

Enacting Reflection: A New Approach to Workplace Complexities

2020 ◽  
Vol 22 (3) ◽  
pp. 320-332
Author(s):  
Sean Justice ◽  
Emily Morrison ◽  
Lyle Yorks
Keyword(s):  
Human Resource Development ◽  
Workplace Learning ◽  
Active Engagement ◽  
Social Environments ◽  
Theoretical Understanding ◽  
New Approach ◽  
Practical Applications ◽  
Emergent Change ◽  
Traditional Approaches ◽  
Complexity Theories

The Problem Change has changed, and workplaces are grappling with new complexities and ambiguities. Human resource development (HRD) scholar-practitioners are called upon to help workplaces learn to navigate these changes; however, traditional approaches have limited utility when dealing with dynamic, emergent change. To address these limitations, scholars have proposed adopting enactive approaches that are rooted in systems thinking and complexity theories, but there is limited understanding of what this means in HRD practice. The Solution This article explores HRD responses to change from an enactive perspective. Enactivism suggests that people create their context through engagement with physical and social environments. From this perspective, reflection is not necessarily “on” experience, as if somehow separate from it. Rather, reflection is active engagement in, by, and through experience. This article aims to expand theoretical understanding and practical applications of enactivism in workplace learning. The Stakeholders HRD scholar-practitioners seeking new options for navigating workplace learning complexities.

scholarly journals Advances in quantum light emission from 2D materials

Nanophotonics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 2017-2032 ◽  
Author(s):  
Chitraleema Chakraborty ◽  
Nick Vamivakas ◽  
Dirk Englund
Keyword(s):  
Optical Properties ◽  
Binding Energy ◽  
Momentum Space ◽  
Recent Progress ◽  
Light Emission ◽  
2D Materials ◽  
Two Dimensional ◽  
Theoretical Understanding ◽  
Practical Applications ◽  
Spin Properties

AbstractTwo-dimensional (2D) materials are being actively researched due to their exotic electronic and optical properties, including a layer-dependent bandgap, a strong exciton binding energy, and a direct optical access to electron valley index in momentum space. Recently, it was discovered that 2D materials with bandgaps could host quantum emitters with exceptional brightness, spectral tunability, and, in some cases, also spin properties. This review considers the recent progress in the experimental and theoretical understanding of these localized defect-like emitters in a variety of 2D materials as well as the future advantages and challenges on the path toward practical applications.

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