scholarly journals Numerical Modeling for Engineering Analysis and Designing of Optimum Support Systems for Headrace Tunnel

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Sajjad Hussain ◽  
Zahid Ur Rehman ◽  
Noor Mohammad ◽  
Muhammad Tahir ◽  
Khan Shahzada ◽  
...  
Keyword(s):  
Rock Mass ◽  
Support Systems ◽  
Research Work ◽  
Strength Properties ◽  
Efficient Design ◽  
Headrace Tunnel ◽  
And Performance ◽  
Selection Of

The empirical and numerical design approaches are considered very important in the viable and efficient design of support systems, stability analysis for tunnel, and underground excavations. In the present research work, the rock mass rating (RMR) and tunneling quality index (Q-system) were used as empirical methods for characterization of rock mass based on real-time geological and site geotechnical data and physical and strength properties of rock samples collected from the alignment of tunnel. The rock mass along the tunnel axis was classified into three geotechnical units (GU-1, GU-2, and GU-3). The support systems for each geotechnical unit were designed. The 2D elastoplastic finite-element method (FEM) was used for the analysis of rock mass behavior, in situ and redistribution stresses, plastic thickness around the tunnel, and performance of the design supports for the selection of optimum support system among RMR and Q supports for each geotechnical unit of tunnel. Based on results, Q support systems were found more effective for GU-1 and GU-2 as compared to RMR support systems and RMR support systems for GU-3 as compared to Q support systems.

scholarly journals Desulphurisation of Biogas: A Systematic Qualitative and Economic-Based Quantitative Review of Alternative Strategies

2019 ◽  
Vol 3 (3) ◽  
pp. 76 ◽  
Author(s):  
Oseweuba Valentine Okoro ◽  
Zhifa Sun
Keyword(s):  
Quantitative Comparison ◽  
Negative Consequences ◽  
Qualitative Comparison ◽  
Quantitative Review ◽  
Current State ◽  
Negative Impacts ◽  
State Of Research ◽  
And Performance ◽  
Selection Of

The desulphurisation of biogas for hydrogen sulphide (H2S) removal constitutes a significant challenge in the area of biogas research. This is because the retention of H2S in biogas presents negative consequences on human health and equipment durability. The negative impacts are reflective of the potentially fatal and corrosive consequences reported when biogas containing H2S is inhaled and employed as a boiler biofuel, respectively. Recognising the importance of producing H2S-free biogas, this paper explores the current state of research in the area of desulphurisation of biogas. In the present paper, physical–chemical, biological, in-situ, and post-biogas desulphurisation strategies were extensively reviewed as the basis for providing a qualitative comparison of the strategies. Additionally, a review of the costing data combined with an analysis of the inherent data uncertainties due underlying estimation assumptions have also been undertaken to provide a basis for quantitative comparison of the desulphurisation strategies. It is anticipated that the combination of the qualitative and quantitative comparison approaches employed in assessing the desulphurisation strategies reviewed in the present paper will aid in future decisions involving the selection of the preferred biogas desulphurisation strategy to satisfy specific economic and performance-related targets.

scholarly journals Effects Of Different Empirical Design Approaches For Size Galleries On The Behaviour Of Rock Masses During The Excavation Operation: Excavation Case At BAE Well

2021 ◽  
Vol 12 (5) ◽  
pp. 1167-1177
Author(s):  
Ismail Zaki, Et. al.
Keyword(s):  
Rock Mass ◽  
Support Systems ◽  
Resistance Index ◽  
In Situ Stress ◽  
Tunnel Excavation ◽  
High In Situ Stress ◽  
Rock Mass Quality ◽  
Empirical Approaches ◽  
Empirical Design

The characterization of rock massifs is a delicate job; indeed, it is possible to understand the behaviour of intact rocks individually by laboratory tests but it is difficult to characterize them on the whole rock mass, which has undergone a complex geological history. Empirical approaches play an important role in the excavation of galleries and the design of support systems. These approaches are considered very effective in optimizing the tunnel excavation process. Several reliable empirical approaches have been developed, but the selection or use of an appropriate empirical method to design the tunnel excavation remains a difficult task. Therefore, in this work, the analysis of four approaches, the most used, of different empirical design was carried out to determine the behaviour of the rock mass during its excavation in a state of high in situ stress. This study was carried out on the scale of the ST2 rock mass of the worksite (BAE well 3) at the Bouazzer mine. These approaches include the AFTES classification, rock mass index (RMR), rock mass quality (Q) and geological resistance index (GSI). Based on the simulated statistical results obtained from said empirical approaches, through the finite element calculation, it was found that the application of the rock mass quality approach is very efficient in the excavation of the rock mass. gallery of size because it makes it possible to take into account the equivalent dimensions of the gallery, the stress condition in situ due to the excavation and the heights of overburden which are considered as major elements of the stability of the gallery. The method provides an optimized reinforcement and support design. In addition, this study will serve as a valuable basic document for the geotechnical engineer to design and plan support systems in the excavation of galleries under high in-situ stress.

Microstructure and performance characterization of in-situ Co2FeO4 whiskers reinforced YIG/YIG joints

2021 ◽  
pp. 111323
Author(s):  
Qianqian Chen ◽  
Panpan Lin ◽  
Xuanyu Du ◽  
Wumo Du ◽  
Tiesong Lin ◽  
...  
Keyword(s):  
Performance Characterization ◽  
And Performance ◽  
Microstructure And Performance

Effects of the Interface Curvature and Dendrite Orientation in Directional Solidification of Bulk Transparent Alloys

2006 ◽  
Vol 508 ◽  
pp. 337-342 ◽  
Author(s):  
Cedric Weiss ◽  
Nathalie Bergeon ◽  
Nathalie Mangelinck-Noël ◽  
Bernard Billia
Keyword(s):  
Directional Solidification ◽  
Optical Methods ◽  
Fundamental Physics ◽  
Materials Engineering ◽  
Interface Curvature ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Selection Of

The properties of structural materials are to a large extent determined by the solid microstructure so that the understanding of the fundamental physics of microstructure formation is critical in the field of materials engineering. A directional solidification facility dedicated to the characterization of solid-liquid interface morphology by means of optical methods has been developed by CNES in the frame of the DECLIC project. This device enables in situ and real time studies on bulk transparent materials. The aim of the project is to perform experiments in microgravity to eliminate the complex couplings between solidification and convection and to get reliable benchmark data to validate and calibrate theoretical modeling and numerical simulations. Presently, ground experiments are performed to finalize the design and the experimental procedures and to guarantee the accuracy of the measurements. These experiments also provide reference data for the study of solidification microstructure dynamics in the presence of buoyancy-driven natural convection. Recent progress is presented concerning the control of the interface shape (critical for pattern analysis), the selection of single crystal of defined orientation (critical for dendritic growth) and the analysis of the dendrite shape.

scholarly journals Formulation and Characterization of Tranylcypromine loaded Polymeric Micellar In-Situ Nasal Gel for treatment of Depression

2020 ◽  
pp. 149-165
Keyword(s):  
Polymeric Micelles ◽  
Research Work ◽  
In Vitro Release ◽  
Polymeric Micelle ◽  
In Situ Gel ◽  
Treatment Of Depression ◽  
In Situ Nasal Gel

:Tranylcypromine is a drug used as antidepressant,anxiolytic, nonselective MAO A/B inhibitor. This drug is used to treat depression.The research was conducted to develop a polymeric micelle using a block copolymer, Pluronic F-68 and Gelucire 50/13 to improve the permeability of Tranylcypromine (TCP). A direct dissolution method was used to prepare polymeric micelles. The prepared micelles were characterised for particle size, % EE, zeta potential, in-vitro release. These micelles solution was used to prepare in situ gel by cold method in order to achieve controlled release. Central composite design was used for optimization of both polymeric micelles and insitu nasal gel.The main objective of this research work is to develop formulation acting centrally without undergoing first pass metabolism i.ie. directly nasal to brain delivery route.

Preliminary results from interdisciplinary fault characterization in the Bedretto Underground Laboratory

2020 ◽  
Author(s):  
Alexis Shakas ◽  
Hannes Krietsch ◽  
Marian Hertrich ◽  
Nima Gholizadeh ◽  
Katrin Plenkers ◽  
...  
Keyword(s):  
Rock Mass ◽  
Fracture Zone ◽  
Geothermal Energy ◽  
Swiss Alps ◽  
Underground Laboratory ◽  
Data Sets ◽  
Remote Imaging ◽  
Wide Range

<p>Engineered Geothermal Systems (EGS) are gaining increasing popularity as a source of renewable energy without significant CO2 emissions. Fractured crystalline rock masses offer a promising environment for exploitation of geothermal energy. In such a setting, fractures and faults are the main conduits for fluid flow and heat transport. In-situ fracture permeabilities are usually too low at depths where rock mass temperatures are sufficiently high for geothermal energy production. Therefore, a suitable heat exchanger needs to be engineered by hydraulic stimulations. A proper in-situ characterization of the fracture geometry and hydro-mechanical properties is of primary importance for the design of the stimulation operations. This is often the most challenging task, since the majority of the fractures in the reservoir are usually inaccessible for direct characterization.</p><p> </p><p>The Bedretto Underground Laboratory for Geosciences (BULG) provides a novel and unique environment to study EGS-related processes, such as seismo-hydro-mechanical fault zone response during hydraulic stimulation and subsequent fluid circulation experiments. The laboratory is hosted in an access tunnel from the Bedretto Valley in the Southern Swiss Alps to a railway tunnel from the Matterhorn-Gotthard-Bahn. The overburden of more than 1000 m above the BULG provides conditions that are approaching those of realistic EGS systems. For the rock mass characterization, three boreholes were drilled perpendicular to tunnel axis with lengths ranging from 190 m to 300 m.</p><p> </p><p>We present first data sets from a variety of methodologies, ranging from hydrological tests to geophysical borehole- and remote-imaging. The complementary nature of these data sets allows us to construct a preliminary three dimensional geological model. Notably, the individual measurements yielded information over a multitude of scales, ranging from millimeter-scale core-log information to decameter scale low-frequency Ground Penetrating Radar measurements. Such a wide range of scales is critical for the characterization of EGS reservoirs. The most prominent feature found is a large-scale fracture zone that extends across the entire investigation volume. This fracture zone will be the target for upcoming stimulation experiments.</p>

Designing for Presence and Performance: The Case of the Virtual Fish Tank

2003 ◽  
Vol 12 (4) ◽  
pp. 374-386 ◽  
Author(s):  
Wooyoung Shim ◽  
Gerard Jounghyun Kim
Keyword(s):  
System Development ◽  
Research Work ◽  
Computation Time ◽  
Frame Rate ◽  
Content Creation ◽  
Development Approach ◽  
And Performance ◽  
Set Up ◽  
Fish Tank

Although much research work has focused on identifying different factors that affect presence, it is still not clear how to effectively combine these results to create a content with high presence with respect to a given hardware set-up and limited computing resources. This paper proposes a concept of level of presence (LOP) in which we attempt to select a set of presence elements and their levels to maximize their “contribution” toward the overall presence subject to system resources. Such an optimization scheme would require a reasonable characterization of the computational costs and a sufficient knowledge of the relative and collective merits of various presence elements. We made an attempt to apply the LOP concept to VR system design for a particular application, a virtual fish tank. The purpose of this study is to assess the usefulness of the LOP concept and introduce science into content creation. We selected two important presence elements—the field of view (FOV) and the simulation level of detail (SLOD)—and quantified their costs in terms of the required computation time. Next, we ran a simple experiment to quantify the relative benefits of those two presence factors. For this application, it was found that providing more lifelike simulation, for instance, incurred needlessly expensive computations compared to the amount of increased benefits. Based on the result, the virtual fish tank was configured with the appropriate FOV and SLOD for maximum presence under different conditions, such as the preferred frame rate and total number of objects. We discuss the merits of such a presence-driven VR system development approach.

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