scholarly journals Effect of PolyCom Admixture on Geotechnical Properties of Black Cotton Soil

2020 ◽  
Vol 8 (5) ◽  
pp. 5280-5284
Keyword(s):  
Clayey Soil ◽  
Geotechnical Properties ◽  
Black Cotton Soil ◽  
Construction Costs ◽  
The Past ◽  
Shrinkage Cracks ◽  
Soil Cement ◽  
Time Period ◽  
Permeability Increase ◽  
Properties Of Soil

Over the past few years to stabilize the clayey soil which has been generally adopting these days in developing paved and unpaved roads, cement based products such as soil cement, and different kind of materials like lime are used. These additives being used in soil improves the strength, durability and workability of soil and generally it leads to a thickness reduction of the pavement layers. Regrettably, boundless amount of conventional additives are required to strengthen the soil used in pavements which leads to relatively long curing time. The compaction action should be completed within the stipulated time period, because which significantly affects the construction costs. The other disadvantages associated with cement stabilized layers can be the shrinkage cracks developed which reflect rapidly through asphaltic surfaces and cause greater deterioration. Therefore the development of polymeric based additives has been of particularly interest as they demonstrate many added advantages; such as their ability to reduce permeability, increase durability, allow non time depending during the mixing stage and provide increased flexibility. In this project PolyCom is being used as additive from the list of various Polymer Stabilization Materials. The advantage being selecting PolyCom as it does not create a chemical reaction and is not a rigid setting agent. Black cotton soil was taken in the analysis and it is added with PolyCom to find out the changes in the properties and from the inference of results it was observed that PolyCom addition enhances the Geotechnical properties of soil when compared to the black cotton soil used alone as a stabilized material.

scholarly journals Influence of Nano Silica on the Geotechnical Properties of Clayey Soil Stabilized with Lime

2018 ◽  
Vol 7 (1) ◽  
pp. 28-32
Author(s):  
R. Iswarya . ◽  
V. Satheeskumar .
Keyword(s):  
Soil Stabilization ◽  
Clayey Soil ◽  
Strength Properties ◽  
Geotechnical Properties ◽  
Curing Time ◽  
Nano Silica ◽  
Economic Issues ◽  
Stabilized Soil ◽  
Ucs Test ◽  
Properties Of Soil

The soil must be able to withstand the load and transfer it to ground within the range of allowable deformations, for which it must possess good physical and geotechnical properties. The conventional method of stabilization such as removal and replacement of ill – suited soils incur higher cost and is time consuming. A new method of stabilization, designated as chemical stabilization can be adopted. This method initiate chemical reactions such as cation exchange, pozzolanic activity etc., which consequently enhance the geotechnical properties of soil. In this study, the mechanical behavior of soil is improved by addition of nanoparticles i.e., nano silica along with cementitious material, lime. Considering economic issues of nano silica usage and results of this research in soil stabilization projects, in this study 0, 1, 3 and 5 % weight of nano silica is used as well as 0, 2 and 4 % weight of lime is used. The effect of these replacements is studied by Atterberg limits test, compaction test and unconfined compressive strength (UCS) test. The effect of curing time on samples at 3, 7 and 28 days of age has also been investigated. The optimum percentage replacement of nano silica in lime stabilized soil is determined. The microstructure of the stabilized soil is studied by Scanning electron microscopy (SEM) test. Thus the results proved that there is a significant improvement in the plasticity, compaction and strength properties with slight addition of nano silica in clayey soil mixed with lime.

World Economy: Prospects and Barriers for Recovery

2012 ◽  
pp. 61-83 ◽  
Author(s):  
M. Ershov
Keyword(s):  
World Economy ◽  
Western World ◽  
Short Time Period ◽  
Market Segments ◽  
Junk Bonds ◽  
The Past ◽  
Time Period ◽  
The Us ◽  
Global Liquidity ◽  
Short Time

According to the latest forecasts, it will take 10 years for the world economy to get back to “decent shape”. Some more critical estimates suggest that the whole western world will have a “colossal mess” within the next 5–10 years. Regulators of some major countries significantly and over a short time‑period changed their forecasts for the worse which means that uncertainty in the outlook for the future persists. Indeed, the intensive anti‑crisis measures have reduced the severity of the past problems, however the problems themselves have not disappeared. Moreover, some of them have become more intense — the eurocrisis, excessive debts, global liquidity glut against the backdrop of its deficit in some of market segments. As was the case prior to the crisis, derivatives and high‑risk operations with “junk” bonds grow; budget problems — “fiscal cliff” in the US — and other problems worsen. All of the above forces the regulators to take unprecedented (in their scope and nature) steps. Will they be able to tackle the problems which emerge?

scholarly journals One Year of the COVID-19 Pandemic in Galicia: A Global View of Age-Group Statistics during Three Waves

2021 ◽  
Vol 18 (10) ◽  
pp. 5104
Author(s):  
Iván Area ◽  
Henrique Lorenzo ◽  
Pedro J. Marcos ◽  
Juan J. Nieto
Keyword(s):  
Intensive Care Unit ◽  
Hospital Admissions ◽  
Age Groups ◽  
Age Group ◽  
Nw Spain ◽  
The Past ◽  
Global View ◽  
Time Period ◽  
Key Variables ◽  
One Year

In this work we look at the past in order to analyze four key variables after one year of the COVID-19 pandemic in Galicia (NW Spain): new infected, hospital admissions, intensive care unit admissions and deceased. The analysis is presented by age group, comparing at each stage the percentage of the corresponding group with its representation in the society. The time period analyzed covers 1 March 2020 to 1 April 2021, and includes the influence of the B.1.1.7 lineage of COVID-19 which in April 2021 was behind 90% of new cases in Galicia. It is numerically shown how the pandemic affects the age groups 80+, 70+ and 60+, and therefore we give information about how the vaccination process could be scheduled and hints at why the pandemic had different effects in different territories.

scholarly journals Metaphors of migration over time

2021 ◽  
pp. 095792652199215
Author(s):  
Charlotte Taylor
Keyword(s):  
Emigration And Immigration ◽  
Emigrants And Immigrants ◽  
Economic Resource ◽  
Historical Discourse ◽  
Continuity And Change ◽  
The Past ◽  
Perception Of Control ◽  
Time Period ◽  
Metaphor Use ◽  
The Uk

This paper aims to cast light on contemporary migration rhetoric by integrating historical discourse analysis. I focus on continuity and change in conventionalised metaphorical framings of emigration and immigration in the UK-based Times newspaper from 1800 to 2018. The findings show that some metaphors persist throughout the 200-year time period (liquid, object), some are more recent in conventionalised form (animals, invader, weight) while others dropped out of conventionalised use before returning (commodity, guest). Furthermore, we see that the spread of metaphor use goes beyond correlation with migrant naming choices with both emigrants and immigrants occupying similar metaphorical frames historically. However, the analysis also shows that continuity in metaphor use cannot be assumed to correspond to stasis in framing and evaluation as the liquid metaphor is shown to have been more favourable in the past. A dominant frame throughout the period is migrants as an economic resource and the evaluation is determined by the speaker’s perception of control of this resource.

scholarly journals Investigation of geotechnical properties of soil samples in Isu-Njaba Imo State

2021 ◽  
Vol 1036 (1) ◽  
pp. 012035
Author(s):  
A C Ekeleme ◽  
O H Ibearugbulem ◽  
E I Ugwu ◽  
C E Njoku ◽  
E C Amanamba ◽  
...  
Keyword(s):  
Soil Samples ◽  
Geotechnical Properties ◽  
Imo State ◽  
Properties Of Soil

If things go South: The renewed policy of sport mega events allocation and its implications for future research

2021 ◽  
pp. 101269022098134
Author(s):  
Billy Graeff ◽  
Jorge Knijnik
Keyword(s):  
21St Century ◽  
Public Expenditure ◽  
Global South ◽  
International Olympic Committee ◽  
Future Research ◽  
Construction Costs ◽  
Mega Events ◽  
The Past ◽  
Global North ◽  
Analytical Tools

The past few decades have seen an increase of sport mega events (SMEs) held outside the Global North. This tendency has been accompanied by a growing public expenditure in these events. This paper employs selected Global South SMEs to discuss this trend. By critically analysing public documents, biddings and reports, the study traces comparisons between 21st-century Global South and Global North SMEs expenditures, in the revenue of franchise owners (FIFA and the International Olympic Committee), in construction costs within the budgets and in the costs related to security. This comprehensive and intertwined investigation shows the need for new analytical tools – such as the Renewed Policy of Sport Mega Events Allocation, a concept developed here - to better capture the central questions posed by the challenges of ‘SMEs going South’.

scholarly journals Validation of SCIAMACHY limb NO<sub>2</sub> profiles using solar occultation measurements

2011 ◽  
Vol 4 (4) ◽  
pp. 4753-4800
Author(s):  
R. Bauer ◽  
A. Rozanov ◽  
C. A. McLinden ◽  
L. L. Gordley ◽  
W. Lotz ◽  
...  
Keyword(s):  
The Past ◽  
Middle Latitudes ◽  
Solar Occultation ◽  
Time Period ◽  
Vertical Distributions ◽  
Global Coverage ◽  
Scanning Imaging ◽  
Diurnal Effect ◽  
Better Than ◽  
Balloon Measurements

Abstract. The increasing amounts of reactive nitrogen in the stratosphere necessitates accurate global measurements of stratospheric nitrogen dioxide (NO2). Over the past decade, the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) instrument on ENVISAT (European Environmental Satellite) has been providing global coverage of stratospheric NO2 every 6 days, which is otherwise difficult to achieve with other systems (e.g. balloon measurements, solar occultation). In this study, the vertical distributions of NO2 retrieved from limb measurements of the scattered solar light from the SCIAMACHY instrument are validated using NO2 products from three different satellite instruments (SAGE II, HALOE and ACE-FTS). The retrieval approach, as well as the sensitivity of the SCIAMACHY NO2 limb data product are discussed, and the photochemical corrections needed to make this validation feasible, as well as the chosen collocation criteria are described. For each instrument, a time period of two years is analyzed with several hundreds of collocation pairs for each year and instrument. The agreement between SCIAMACHY and each instrument is found to be better than 10 % between 22–24 km and 40 km. Additionally, NO2 amounts in three different latitude regions are validated individually, with considerably better agreements in high and middle latitudes compared to tropics. Differences with SAGE II and ACE-FTS below 20 km are consistent with those expected from the diurnal effect.

Performance of Large-Scale Seasonal Thermal Energy Stores

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
F. Ochs ◽  
W. Heidemann ◽  
H. Müller-Steinhagen
Keyword(s):  
Thermal Energy ◽  
Large Scale ◽  
Fossil Fuels ◽  
Waste Heat ◽  
Type System ◽  
Solar Thermal Energy ◽  
Construction Costs ◽  
The Past ◽  
Energy Stores ◽  
Construction Type

More than 30 international research and pilot seasonal thermal energy stores (TESs) were realized within the past 30 years. Experiences with operation of these systems show that TES are technically feasible and work well. Seasonal storage of solar thermal energy or of waste heat from heat and power cogeneration plants can significantly contribute to substitute fossil fuels in future energy systems. However, performance with respect to thermal losses and lifetime has to be enhanced, while construction costs have to be further reduced. This paper gives an overview about the state-of-the-art of seasonal thermal energy storage with the focus on tank and pit TES construction. Aspects of TES modeling are given. Based on modeled and measured data, the influence of construction type, system configuration, and boundary conditions on thermal losses of large-scale TES is identified. The focus is on large-scale applications with tank and pit thermal energy stores and on recent investigations on suitable materials and constructions. Furthermore, experiences with the operation of these systems with respect to storage performance are discussed.

scholarly journals Geotechnical Evaluation of Diesel Contaminated Clayey Soil

2021 ◽  
Vol 11 (14) ◽  
pp. 6451
Author(s):  
Christian E. Hernández-Mendoza ◽  
Pamela García Ramírez ◽  
Omar Chávez Alegría
Keyword(s):  
Contaminated Soils ◽  
Clayey Soil ◽  
Friction Angle ◽  
Geotechnical Properties ◽  
Natural Soil ◽  
Osmotic Suction ◽  
The One ◽  
Available Information ◽  
The Impact ◽  
Diesel Contamination

Soil contamination by different hydrocarbons has rapidly expanded worldwide, surpassing the self-purification capacity of soils and increasing the number of contaminated sites. Although much effort has been devoted to study the effects of diesel contamination on the geotechnical properties of soil, there is still limited available information about it. Moreover, there is no available information about the maximum diesel retention that soil can have and its effect on the geotechnical behavior of the soil. Thus, in this paper, we determined the maximum diesel retention by an unsaturated clayey soil and evaluated the impact of diesel contamination on its geotechnical properties. The results showed that the soil could only retain 12.6% of the added diesel and the excess was expulsed. At such a diesel concentration, the saturation rate of the soil was lower than 80%. Diesel contamination increased the plasticity and the internal friction angle of the soil, while its cohesion was considerably decreased. It should be noted that the matric suction of contaminated soil was lower than the one obtained for natural soil. However, its osmotic suction was considerably higher. This indicates that osmotic suction must be considered to evaluate the shear strength of contaminated soils.

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