scholarly journals Research on Evolution Characteristics of Shale Crack Based on Simultaneous Monitoring of Multi-Parameters

2022 ◽  
Vol 12 (2) ◽  
pp. 860
Author(s):  
Qiao Chen ◽  
Fenglin Xu ◽  
Pengcheng Su ◽  
Honglin Zhu ◽  
Yifang Zhang ◽  
...  
Keyword(s):  
Reference Value ◽  
Mechanical Parameters ◽  
Crack Evolution ◽  
Loading Test ◽  
Acoustic Data ◽  
Video Information ◽  
Evolution Characteristics ◽  
Experimental Apparatus ◽  
Key Factor ◽  
Set Up

Meso-crack evolution mechanism of shale is a key factor affecting the mechanical properties of shale. In order to explore evolution laws of cracks in shale during loading, a meso-crack monitoring system, loading test equipment and an automatic ultrasonic data acquisition system were set up. On this basis, a set of experimental apparatus simultaneous monitoring multi-parameters of shale micro-crack was designed, and destruction experiments of shale samples with different bedding angles were carried out to find out evolution characteristics of cracks. The results show the following: (1) The designed apparatus can monitor ultrasonic, mechanical and video information simultaneously of crack evolution in the entire process of shale destruction under load to provide information for analyzing acoustic and mechanical characteristic responses of crack propagation at key time nodes. (2) With an increase in load, shale will undergo four stages of destruction: crack initiation, propagation, penetration and overall failure. In the course of these stages, acoustic characteristics and mechanical characteristics are in good agreement, which proves the validity of predicting rock mechanical parameters with acoustic data. (3) During the loading process of shale, the main amplitude of acoustic wave is more sensitive than mechanical parameters to the change of rock cracks. Research results have important theoretical reference value for evaluating wall stability of shale gas horizontal well with ultrasonic data.

scholarly journals Influence of the Number of Queens on Nest Establishment: Native and Invasive Ant Species

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 591
Author(s):  
Irene Castañeda ◽  
Elsa Bonnaud ◽  
Franck Courchamp ◽  
Gloria Luque
Keyword(s):  
Species Differences ◽  
Argentine Ants ◽  
Invasive Ant ◽  
Internal Factors ◽  
Ant Colonies ◽  
Worker Behavior ◽  
Key Factor ◽  
Nest Maintenance ◽  
Set Up ◽  
Tapinoma Nigerrimum

As a critical stage in the life cycle of ant colonies, nest establishment depends on external and internal factors. This study investigates the effect of the number of queens on queen and worker behavior during nest establishment in invasive Argentine ants (Linepitema humile) and native Mediterranean Tapinoma nigerrimum. We set up experimental colonies with the same number of workers but with one or six queens. At different time points, we recorded the positions of queens and workers inside and outside the nest. Our results highlight the influence of the number of queens on the position of queens and workers with between-species differences. Queens of both species entered the nests more quickly when there were six queens. During nest establishment, more workers were inside nests with six queens for both species, with this effect being greater for T. nigerrimum. Once nests were established, fewer workers of both species were engaged in nest maintenance and feeding in nests with six queens; T. nigerrimum had fewer workers engaged in patrolling. These results suggest that the number of queens is a key factor driving queen and worker behavior during and after nest establishment with different species responses.

scholarly journals A 2-D model for Intermediate Temperature Solid Oxide Fuel Cells Preliminarily Validated on Local Values

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 36 ◽  
Author(s):  
Bruno Conti ◽  
Barbara Bosio ◽  
Stephen John McPhail ◽  
Francesca Santoni ◽  
Davide Pumiglia ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Operating Conditions ◽  
Solid Oxide ◽  
Intermediate Temperature ◽  
Physical Parameters ◽  
Local Concentration ◽  
Oxide Fuel ◽  
Molten Carbonate ◽  
Experimental Apparatus ◽  
Set Up

Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC) technology offers interesting opportunities in the panorama of a larger penetration of renewable and distributed power generation, namely high electrical efficiency at manageable scales for both remote and industrial applications. In order to optimize the performance and the operating conditions of such a pre-commercial technology, an effective synergy between experimentation and simulation is fundamental. For this purpose, starting from the SIMFC (SIMulation of Fuel Cells) code set-up and successfully validated for Molten Carbonate Fuel Cells, a new version of the code has been developed for IT-SOFCs. The new release of the code allows the calculation of the maps of the main electrical, chemical, and physical parameters on the cell plane of planar IT-SOFCs fed in co-flow. A semi-empirical kinetic formulation has been set-up, identifying the related parameters thanks to a devoted series of experiments, and integrated in SIMFC. Thanks to a multi-sampling innovative experimental apparatus the simultaneous measurement of temperature and gas composition on the cell plane was possible, so that a preliminary validation of the model on local values was carried out. A good agreement between experimental and simulated data was achieved in terms of cell voltages and local temperatures, but also, for the first time, in terms of local concentration on the cell plane, encouraging further developments. This numerical tool is proposed for a better interpretation of the phenomena occurring in IT-SOFCs and a consequential optimization of their performance.

Fringe fields are important when examining molecular orientation in a cold ammonia beam

2021 ◽  
Author(s):  
Paul Bertier ◽  
Brianna Heazlewood
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Molecular Orientation ◽  
Molecular Beam ◽  
Buffer Gas ◽  
State Distribution ◽  
Experimental Apparatus ◽  
Set Up ◽  
A Minor ◽  
Fringe Fields

Abstract External fields have been widely adopted to control and manipulate the properties of gas-phase molecular species. In particular, electric fields have been shown to focus, filter and decelerate beams of polar molecules. While there are several well-established approaches for controlling the velocity and quantum-state distribution of reactant molecules, very few of these methods have examined the orientation of molecules in the resulting beam. Here we show that a buffer gas cell and three-bend electrostatic guide (coupled to a time-of-flight set-up) can be configured such that 70% of ammonia molecules in the cold molecular beam are oriented to an external electric field at the point of detection. With a minor alteration to the set-up, an approximately statistical distribution of molecular orientation is seen. These observations are explained by simulations of the electric field in the vicinity of the mesh separating the quadrupole guide and the repeller plate. The combined experimental apparatus therefore offers control over three key properties of a molecular beam: the rotational state distribution, the beam velocity, and the molecular orientation. Exerting this level of control over the properties of a molecular beam opens up exciting prospects for our ability to understand what role each parameter plays in reaction studies.

Correlation of yarn feeding to the dimensional and elastic parameters of tubular knitted fabric

2021 ◽  
pp. 004051752110371
Author(s):  
Yanhong Yuan ◽  
Jie Zhong ◽  
Xin Ru ◽  
Bing Liu
Keyword(s):  
Production Efficiency ◽  
Critical Factor ◽  
Knitted Fabric ◽  
Loop Formation ◽  
Knitted Fabrics ◽  
Machine Operators ◽  
Key Factor ◽  
Optimal Feed ◽  
Feeding Parameters ◽  
Set Up

The yarn feeding for a loop formation is a critical factor in determining the size and elasticity of highly elastic knitted fabrics. Currently, the prevalent production processes rely on experienced machine operators to set up the optimal feed rate by trial and error. To improve production efficiency and reduce the reliance on the operator’s skill, we attempt to create a structure model of tubular knitted fabric that could correlate the size as well as elasticity of fabric with the loop geometry parameters (wale spacing, course spacing) of the yarn feeding. The experimental tensile test of the elastic fabric verified that the model is able to deduce the yarn feeding parameters from the elasticity and dimensional requirements of the fabric to be knitted. It is also illustrated that the yarn feeding is a key factor in controlling the elasticity of knitted fabrics.

A RBF Neural Network Approach for Fitting Creep Curve of Sandstone

2010 ◽  
Vol 171-172 ◽  
pp. 274-277
Author(s):  
Yun Liang Tan ◽  
Ze Zhang
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Creep Curve ◽  
Bp Neural Network ◽  
Rbf Neural Network ◽  
Reference Value ◽  
Network Approach ◽  
Neural Network Approach ◽  
Training Time ◽  
Set Up

In order to quest an effective approach for predicate the rheologic deformation of sandstone based on some experimental data, an improved approaching model of RBF neural network was set up. The results show, the training time of improved RBF neural network is only about 10 percent of that of the BP neural network; the improved RBF neural network has a high predicating accuracy, the average relative predication error is only 7.9%. It has a reference value for the similar rock mechanics problem.

scholarly journals The Effect of Transversal Connection in the in-Plane Response of Double-Leaf Brick Masonry Walls

2021 ◽  
Author(s):  
Lorenzo Scandolo ◽  
Stefano Podestà
Keyword(s):  
Structural Safety ◽  
Masonry Walls ◽  
Masonry Building ◽  
Mechanical Parameters ◽  
Compression Tests ◽  
Knowledge Process ◽  
Diagonal Compression ◽  
Set Up ◽  
Definition Of ◽  
Simplified Mechanical Model

Abstract The evaluation of structural safety derives from the knowledge of material properties. In case of existent masonry building, the definition of reliable mechanical parameters could be a very difficult task to be achieved. For this reason, an estimation of these values is useful, for example it is the first phase of the knowledge process, for simplified mechanical model or when NTD test is the only possibility.The transversal connection in masonry panels is a technological detail that affects the static and seismic behavior and could significantly increase the strength of the element.In this paper the effect of transversal connection in double-leaf brickwork masonry panels is evaluated by diagonal compression tests. To achieve this goal, a new set-up was designed to load each leaf independently.The results have shown an increment of about 20% in strength if transversal connection is present. If the leaves have very different mechanical parameters, the tests highlight an unexpected behavior.

scholarly journals Pristup obrazovnom dizajnu za 2026.

2019 ◽  
Vol 13 (1) ◽  
pp. 123-138
Author(s):  
Željko Burcar
Keyword(s):  
Labor Market ◽  
Empirical Research ◽  
Education System ◽  
Project Approach ◽  
Key Factor ◽  
Project Model ◽  
Market Needs ◽  
Set Up ◽  
Near Future ◽  
Model Algorithm

We live in a society of knowledge? Labor market needs every day set new demands for competences. The project approach to designing education appears to be inevitable. Competences are a key factor and one of the prerequisites for an individual's success in the labor market, which will be even more flexible in the near future. The labor market for 8 years will require many new competencies. The education system must prepare current students for future competencies based on ZVSSOUP model. In this paper, theoretical elements of designing and redesigning educational content have been set up according to project principles. Efficient project model algorithm assumes design from the final goal to the beginning. The proposed algorithm can meet the needs for quick redefinition of the required competencies for the future labor market and will also be tested by future empirical research.

Temperature as a key factor for successful inoculation of soybean with Bradyrhizobium spp. under cool growing conditions in Belgium

2018 ◽  
Vol 156 (4) ◽  
pp. 493-503 ◽  
Author(s):  
J. Pannecoucque ◽  
S. Goormachtigh ◽  
J. Ceusters ◽  
J. Debode ◽  
C. Van Waes ◽  
...  
Keyword(s):  
Field Trials ◽  
Protein Yield ◽  
Control Treatment ◽  
Rhizobial Symbiosis ◽  
Key Factor ◽  
Growing Conditions ◽  
Set Up ◽  
Biological Nitrogen ◽  
Intermediate Performance

AbstractBacterial inoculation of soybean seeds to improve biological nitrogen fixation is a well-known practice to achieve higher seed and protein yield with reduced fertilization. The optimal inoculation strategy in temperate regions is unknown because soybeans are rarely cultivated under colder growing conditions. The aim of the present work was to determine the most suitable inoculation strategy for soybean cultivation in Belgium. Field trials were set up with four Bradyrhizobium inoculants (HiStick, Force 48, Biodoz and Optimize) at two locations over 2 years (2014–2015) and compared with a non-inoculated control treatment. In addition, HiStick was tested at three doses and Optimize at two time periods prior to sowing. Under Belgian conditions, all inoculants were effective in establishing rhizobial symbiosis, resulting in increased yield, protein content, protein yield and thousand-grain weight compared with the non-inoculated control. A single dose of HiStick was sufficient to establish symbiosis. Pre-inoculation with Optimize 2 weeks before sowing gave an intermediate performance for most parameters between the non-inoculated control treatment and inoculation with Optimize 24 h prior to sowing. Among the four products tested, Biodoz seemed the best product for inoculation under cool growing conditions. Based on the atpD gene, the bacterial strain of Biodoz showed complete similarity with Bradyrhizobium diazoefficiens, while strains of other products were identified as Bradyrhizobium japonicum. In vitro growing capacity of the Biodoz strain at 8 °C was higher compared with the other strains. Better cold adaptation of the Biodoz strain might be a possible explanation for the better performance of Biodoz in Belgium.

Testing and Modeling of Mechanical Parameters in Resistance Welding Machines

2013 ◽  
Vol 712-715 ◽  
pp. 1235-1240
Author(s):  
Pei Wu ◽  
Yong An Zhang ◽  
Chuan Zhong Xuan ◽  
Yan Hua Ma
Keyword(s):  
Mechanical Response ◽  
Resistance Welding ◽  
Work Piece ◽  
Mechanical Parameters ◽  
Test Set ◽  
Dynamic Mechanical ◽  
Projection Welding ◽  
Welding Machine ◽  
Equivalent Mass ◽  
Set Up

The dynamic mechanical responses of resistance welding machine,which is mainly governed by the mechanical parameters of the machine, is very important to the weld quality especially in projection welding when collapse or deformation of work piece occurs. In this paper, a mathematical model for characterizing the dynamic mechanical response of resistance welding machine and a special test set-up called breaking test set-up have been developed. Based on the model and the test results, the mechanical parameters of the machine were identified, including the equivalent mass, the damping coefficient, and the stiffness for both electrode systems.

Overcoming Intersectional Barriers

2018 ◽  
pp. 971-993
Author(s):  
Sara L. Parker ◽  
Kay Standing
Keyword(s):  
Life Experiences ◽  
Future Research ◽  
Key Factors ◽  
Policy Makers ◽  
Key Factor ◽  
Women's Lives ◽  
Just Society ◽  
Set Up ◽  
The Impact ◽  
Research And Policy

This chapter discusses the complexity and challenges of exploring the impact of gender on women's ability to realise their potential in Nepal. It demonstrates the limitations of using binary divisions to exploring ‘gender' as a key factor that impacts upon women's lives. By analysing interviews with ‘inspirational' women in Nepal conducted between 2009 and 2012 the chapter highlights the importance of exploring intersectional factors that also influenced women's life experiences. Based on interviews with 34 ‘inspirational' women in Nepal the chapter explores how the term ‘inspirational' is defines and discusses the range of work being done by so many women in Nepal that is truly inspiring. Through a discourse analysis of their stories of childhood and education we can see what key factors have played a role in enabling these women to realise their potential and to overcome intersectional barriers to work in a range of diverse positions, from the first female District Development Officer to the first women to gain her doctorate from overseas, to women who have set up NGOS working towards a more equitable and just society to others who have set up their own businesses or becoming leading academics. The conclusion draws together some key recommendations for future research and policy makers as well as those seeking to promote more equitable sustainable development that truly includes women in the process as autonomous, heterogeneous actors in the development process

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