scholarly journals Special reinforcement solutions of railway permanent ways’ soil substructures

2021 ◽  
Author(s):  
Muayad Habashneh
Keyword(s):  
Shear Strength ◽  
Hydraulic Conductivity ◽  
Soil Stabilization ◽  
Effective Solution ◽  
Geosynthetic Reinforcement ◽  
Rehabilitation Process ◽  
Comprehensive Review ◽  
The Core ◽  
Main Target ◽  
Increasing Demand

This mini review aims to summarize relevant international publications. Thus, based on this, giving a comprehensive review about the reinforcement solutions of permanent ways' soil substructure. Generally, the core weakness of soil is its inadequacy to resist tensile stresses. The main target of strengthening the soil is to enhance the engineering characteristics of the soil to build up specific parameters such as shear strength, compressibility, density, and hydraulic conductivity. In addition, special reinforcement techniques of railway permanent ways' soil substructures will be considered in this paper due to the increasing demand of improving railways and rehabilitation process. The main findings of this study that there are a lot of special reinforcement techniques which can be considered as effective solution for soil stabilization such as geosynthetic reinforcement.

Analysis of the Weak Soil Behavior, Modified Through Cementation

2019 ◽  
Vol 7 (1) ◽  
pp. 27-36
Author(s):  
Nadiia Kopiika ◽  
Yuriy Petrenko
Keyword(s):  
Soil Stabilization ◽  
Theoretical Research ◽  
Soil Behavior ◽  
Weak Soil ◽  
Calculation Technique ◽  
Literature Overview ◽  
Weak Soils ◽  
Chemical Technique ◽  
Increasing Demand

The purpose of the study is to conduct thorough theoretical research and literature overview regarding possible ways of soil stabilization on the basis of this practice increasing demand. In particular an emphasis is made on the chemical technique for weak soils strengthening, due to its prevalence and various practical and economic advantages. Great amount of promiscuous data was analyzed and organized; in addition on its basis an attempt is made to provide convincing calculation technique for further usage in engineering soils` stabilization practice. Besides, various factors which could influence on the results` accuracy are identified with corresponding recommendations for further possible research on this issue.

scholarly journals Investigating collaborative and mobility networks: reflections on the core missions of universities

2021 ◽  
Author(s):  
Zsolt Tibor Kosztyán ◽  
Beáta Fehérvölgyi ◽  
Tibor Csizmadia ◽  
Kinga Kerekes
Keyword(s):  
Social Progress ◽  
Industry Funding ◽  
Multilayer Network ◽  
The Core ◽  
Funding Agencies ◽  
Valid Assessment ◽  
Increasing Demand ◽  
Public Money ◽  
University Performance

AbstractGiven the significant role of universities in economic growth and social progress as well as the increasing demand for greater transparency regarding the use of public money, a valid assessment of university performance has become crucial for various stakeholders, including government, industry, funding agencies, and society at large. Contemporary assessments still focus solely on universities’ properties, thereby failing to capture their network relations. To overcome this limitation, this paper proposes a multilayer network-based method to measure the embeddedness of universities in collaboration and mobility networks. This method has several advantages: first, it is relevant for HEIs’ core missions, introducing a new dimension complementary to the existing rankings; second, it is size invariant; and last but not least, it is fully transparent. The proposed multilayer network approach enables the integration of further networks, which creates opportunities for a more comprehensive assessment of universities’ performance in achieving their core missions.

Fear on the Campaign Trail

2017 ◽  
Author(s):  
Adam I. P. Smith
Keyword(s):  
Federal Government ◽  
Abraham Lincoln ◽  
Effective Solution ◽  
The West ◽  
Campaign Strategies ◽  
Presidential Candidates ◽  
The Core ◽  
White Settlers

This chapter discusses the campaign strategies of the two main presidential candidates in the free states in the 1860 election, Abraham Lincoln and Stephen A. Douglas. Both appealed to voters’ desire to contain the Slave Power and assure access to the West for free white settlers. The core difference between Douglasites and Lincolnites was over the role of the Federal government in resolving the crisis: Republicans wanted to take control in Washington to prevent the nationalisation of slavery; Democrats continued to believe that the most effective solution was decentralisation.

Geophysical mapping of gypsum for exploration of reserves in the Nong Bua area of Thailand

2020 ◽  
pp. qjegh2019-180
Author(s):  
Rungroj Arjwech ◽  
Mark E. Everett ◽  
Sakhon Saengchomphu ◽  
Kittipong Somchat ◽  
Potpreecha Pondthai
Keyword(s):  
Electrical Resistivity ◽  
Construction Projects ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Raw Material ◽  
P Wave ◽  
The Core ◽  
Micro Cracks ◽  
P Wave Velocity ◽  
Increasing Demand

The increasing demand for gypsum as a raw material for construction projects motivates exploration for additional reserves. Electrical resistivity tomography (ERT) and seismic refraction geophysical methods, augmented with borehole and laboratory measurements on core samples, are used here to delineate the top, bottom and lateral boundaries of an important gypsum ore deposit in Thailand, an economically developing region. The gypsum-bearing formation is found throughout the study area to have an irregular upper boundary on account of karstic dissolution processes. The deeper transition from gypsum to anhydrite, however, is not constrained by the measurements. The P-wave velocity measured in the field is consistent with the core specimen measurements. The electrical resistivity of the core specimens, however, is substantially higher than the values measured in the field. The specimen measurements may depend on the presence of micro cracks, whereas electrical resistivity in the field may be affected by the enclosing clay-rich materials.

scholarly journals Analysis and research of quadruped robot’s legs: A comprehensive review

2019 ◽  
Vol 16 (3) ◽  
pp. 172988141984414 ◽  
Author(s):  
Yuhai Zhong ◽  
Runxiao Wang ◽  
Huashan Feng ◽  
Yasheng Chen
Keyword(s):  
Degrees Of Freedom ◽  
Walking Speed ◽  
Load Capacity ◽  
Basic Component ◽  
Application Performance ◽  
Comprehensive Review ◽  
Research Results ◽  
The Core ◽  
Quadruped Robots ◽  
Job Adaptability

As an important basic component of quadruped robots, mechanical legs provide the robots with excellent maneuverability and versatility, which determine the core application performance such as job adaptability, walking speed, and load capacity. A large number of robotics institutes for the last few decades have studied mechanical legs used by quadruped robots and published many research results. In this article, we collect these research results and classify them into three categories (prismatic legs, articulated legs, and redundant articulated legs) according to the degrees of freedom and then introduce and analyze them. On this basis, we summarize and study the design methods of the actuators and mechanical leg structures. Finally, we make some suggestions for the development of quadruped robot’s legs in the future. The motivation of this review is to summarize and analyze previous research efforts and provide useful guidance for future robotic designers to develop more efficient mechanical legs of quadruped robots.

Shear Strength of BC-Soil Admixed with Lime and Bio-Enzyme

2019 ◽  
Vol 969 ◽  
pp. 327-334
Author(s):  
C. Jairaj ◽  
M.T. Prathap Kumar ◽  
H. Muralidhara
Keyword(s):  
Shear Strength ◽  
Soil Stabilization ◽  
Morphological Changes ◽  
Ground Improvement ◽  
High Strength ◽  
Sem Analysis ◽  
Dry Density ◽  
Test Results ◽  
Maximum Dry Density ◽  
Lime Content

This BC Soil are expansive in nature and are problematic because of low shear strength and high compressibility. Review of literatures have proven that addition of lime imparts high strength with a corresponding reduction in swell of BC soils. In addition, Bio-enzymes have also been found to play a key role as activators in improving the characteristics of clayey soils such as BC soil. Development and use of non-traditional ground improvement techniques such as bio-enzymes in combination with lime for soil stabilization helps to reduce the cost and the detrimental effects on the soil environment. In the present study lime and bio-enzymes were used as soil stabilizing agents. Compaction test results on BC soil admixed with different percent of lime indicated that 3% addition lime gives higher maximum dry density of 17kN/m3 with OMC of 21% compare to other addition of lime percentages. Keeping 3% of lime as optimum lime content(OLC), BC Soil was admixed with different dosages of Bio-enzymes 25ml/m3, 50ml/m3, 100 ml/m3,150ml/m3, and 200ml/m3 along with OLC was tested for compaction and unconfined compressive strength(UCC). Further UCC test was carried out for different curing period of 0, 7, 15, 30, and 60 Days to analyse the long term effect of BC soil admixed with bio-enzymes with and without lime content. Morphological and chemical analysis was done by using XRD and SEM analysis, from all the test results it was found that 3%OLC + 75ml/m3 of bio-enzymes for 7 day of curing gives higher UCC of 450 kPa. From the SEM it was found that better bond between particles found to develop in bio-enzyme+ lime admixed BC soil in comparison with lime alone admixed BC soil. XRD studies indicated morphological changes in crystallinity and structure of stabilized BC soil in comparison to BC soil alone.

THE EFFECTS OF SLOPE POSITION AND CROPPING SEQUENCE ON SOIL PHYSICAL PROPERTIES IN PRINCE EDWARD ISLAND

1988 ◽  
Vol 68 (4) ◽  
pp. 763-774 ◽  
Author(s):  
LINNELL M. EDWARDS
Keyword(s):  
Shear Strength ◽  
Hydraulic Conductivity ◽  
Prince Edward Island ◽  
Soil Depth ◽  
Aggregate Stability ◽  
Penetration Resistance ◽  
Slope Position ◽  
Bottom Slope ◽  
Freezing And Thawing ◽  
Freeze Thaw

Soil physical characteristics were examined at depth intervals of 0–15 and 15–30 cm over three slope positions (top-, mid-, and bottom-slope) for three cropping sequences (hay-barley, cereals-barley, and potato-barley). Hydraulic conductivity was a significant (P ≤ 0.05) 40–50% greater at top-slope than mid- or bottom-slope, and aggregate stability percentage was a significant 6–7% greater at bottom-slope than mid- or top-slope when the soil aggregates were pretreated by freezing and thawing (freeze/thaw). Under the potato-barley sequence shear strength, penetration resistance and bulk density were significantly greater than any other sequence by up to 29, 21 and 15%, respectively; while hydraulic conductivity and maximum penetration depth were, respectively, up to 65 and 28% lower than any other sequences. Under hay-barley, hydraulic conductivity and aggregate stability (freeze/thaw) were, respectively, up to a significant 82 and 10% greater than any other sequence. There was, therefore, significantly more compaction under potato-barley and more soil physical enhancement under hay-barley than other respective sequences. Disease severity was up to 55% greater at bottom-slope than at mid-slope or top-slope for Birka barley, which also showed a significant linear decrease (r2 = 0.89) in yield with increasing shear strength. Yield of Perth barley showed a significant linear increase with increasing soil depth (r2 = 0.92) and clay-silt content (r2 = 0.78). Key words: Aggregate stability (freeze/thaw), crop rotation, penetration resistance, shear strength, barley, potatoes, hay

Synthesis of Loaded Silver 4A Zeolite Molecular Sieve with Magnetic Cores of SiO2/(γ-Fe2O3- SiO2) for Demercuration

2014 ◽  
Vol 881-883 ◽  
pp. 1144-1148
Author(s):  
Yue Qin Qiu ◽  
Lei Jia
Keyword(s):  
Key Words ◽  
Molecular Sieve ◽  
Absorption Rate ◽  
Magnetic Particles ◽  
Composite Particles ◽  
Magnetic Composite ◽  
Effective Solution ◽  
The Core ◽  
Magnetic Cores ◽  
4A Zeolite

It is an effective solution to the problem of agglomeration using the magnetic composite SiO2/(γ-Fe2O3- SiO2) instead of traditional magnetic particles Fe3O4as the core of molecular sieve. The traditional hydrothermal method was utilized by means of adding the magnetic composite particles SiO2/(γ-Fe2O3- SiO2) into the pre-made crystallization liquid. Then, a series of magnetic 4A zeolites with varying contents of SiO2/(γ-Fe2O3- SiO2) were synthesized under the condition of ultrasonic crystallization for 6 hours with the power of 100W and temperature of 70 °C . Afterwards, the characterization tests such as XRD,SEM,TG,IR were carried out; the final result showed that the performance of 4A zeolite molecular sieve with SiO2/(γ-Fe2O3- SiO2) is basically identical with the pure 4A zeolite molecular sieve. The absorption rate was 13.5927μg/g by using the 4A zeolite molecular sieve with SiO2/(γ-Fe2O3- SiO2) for the absorption of mercury. Key words: 4A zeolite molecular sieve; magnetic composite; silver loaded;Demercuration

Identification of preferential flow effects on hydraulic conductivity measurements using a fluorescent tracer

2000 ◽  
Vol 37 (2) ◽  
pp. 479-484
Author(s):  
Tom A Al ◽  
David W Blowes
Keyword(s):  
Hydraulic Conductivity ◽  
Measurement Errors ◽  
Preferential Flow ◽  
Conductivity Measurements ◽  
Fine Grained ◽  
The Core ◽  
Core Samples ◽  
Dye Tracer ◽  
Order Of Magnitude ◽  
Constant Head

Core samples were collected from fractured and unfractured zones within fine-grained, unconsolidated mine tailings. The hydraulic conductivity of the core samples was measured in a constant-head permeameter. A fluorescent dye tracer was added to the constant-head reservoir in the permeameter. The tests were run for approximately 48 h, then the cores were sectioned to observe the distribution of dye. Flow through the fractures results in hydraulic conductivity measurements up to one order of magnitude greater than that of unfractured tailings. Observations of the dye distribution in samples following permeameter measurements are used to identify cases where preferential flow in fractures has influenced the hydraulic conductivity measurements. The dye tracer distribution also indicates where measurement errors may be suspected due to flow leakage around the core sample.Key words: tracers, hydraulic conductivity, fractures, tailings.

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