Ground freezing: Mechanical properties, processes and design. State-of-the-art report

2021 ◽  
Vol 11 (5) ◽  
pp. 2000
Author(s):  
Behnam Mobaraki ◽  
Haiying Ma ◽  
Jose Antonio Lozano Galant ◽  
Jose Turmo

This paper presents the application of the observability technique for the structural system identification of 2D models. Unlike previous applications of this method, unknown variables appear both in the numerator and the denominator of the stiffness matrix system, making the problem non-linear and impossible to solve. To fill this gap, new changes in variables are proposed to linearize the system of equations. In addition, to illustrate the application of the proposed procedure into the observability method, a detailed mathematical analysis is presented. Finally, to validate the applicability of the method, the mechanical properties of a state-of-the-art plate are numerically determined.


e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 571-599
Author(s):  
Ricardo Donate ◽  
Mario Monzón ◽  
María Elena Alemán-Domínguez

AbstractPolylactic acid (PLA) is one of the most commonly used materials in the biomedical sector because of its processability, mechanical properties and biocompatibility. Among the different techniques that are feasible to process this biomaterial, additive manufacturing (AM) has gained attention recently, as it provides the possibility of tuning the design of the structures. This flexibility in the design stage allows the customization of the parts in order to optimize their use in the tissue engineering field. In the recent years, the application of PLA for the manufacture of bone scaffolds has been especially relevant, since numerous studies have proven the potential of this biomaterial for bone regeneration. This review contains a description of the specific requirements in the regeneration of bone and how the state of the art have tried to address them with different strategies to develop PLA-based scaffolds by AM techniques and with improved biofunctionality.


2018 ◽  
Vol 8 (10) ◽  
pp. 1737 ◽  
Author(s):  
Arshed Mohammed ◽  
Sallehuddin Haris ◽  
Mohd Nuawi

Recent developments in ultrasonic material testing have increased the need to evaluate the current status of the different applications of piezoelectric elements (PEs). This research have reviewed state-of-the-art emerging new technology and the role of PEs in tests for a number of mechanical properties, such as creep, fracture toughness, hardness, and impact toughness, among others. In this field, importance is given to the following variables, namely, (a) values of the natural frequency to PEs, (b) type and dimensions of specimens, and (c) purpose of the tests. All these variables are listed in three tables to illustrate the nature of their differences in these kinds of tests. Furthermore, recent achievements in this field are emphasized in addition to the many important studies that highlight the role of PEs.


Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1167 ◽  
Author(s):  
Mohammad H. Bhuiyan ◽  
Nicolaine Agofack ◽  
Kamila M. Gawel ◽  
Pierre R. Cerasi

In carbon storage activities, and in shale oil and gas extraction (SOGE) with carbon dioxide (CO2) as stimulation fluid, CO2 comes into contact with shale rock and its pore fluid. As a reactive fluid, the injected CO2 displays a large potential to modify the shale’s chemical, physical, and mechanical properties, which need to be well studied and documented. The state of the art on shale–CO2 interactions published in several review articles does not exhaust all aspects of these interactions, such as changes in the mechanical, petrophysical, or petrochemical properties of shales. This review paper presents a characterization of shale rocks and reviews their possible interaction mechanisms with different phases of CO2. The effects of these interactions on petrophysical, chemical and mechanical properties are highlighted. In addition, a novel experimental approach is presented, developed and used by our team to investigate mechanical properties by exposing shale to different saturation fluids under controlled temperatures and pressures, without modifying the test exposure conditions prior to mechanical and acoustic measurements. This paper also underlines the major knowledge gaps that need to be filled in order to improve the safety and efficiency of SOGE and CO2 storage.


Author(s):  
G. H. Harth

This paper presents the state-of-the-art knowledge concerning the application of powder metallurgy to the fabrication of titanium alloy turbine engine components. The effect of powder type, powder processing, and method of powder consolidation on the mechanical properties and microstructures of P/M parts it discussed. The advantages of using hot isostatic pressing (HIP) in producing engine components is outlined.


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