scholarly journals EFFECT OF WEATHERED SURFACE CRUST LAYER ON STABILITY OF MUAR TRIAL EMBANKMENT

2015 ◽  
Vol 76 (2) ◽  
Author(s):  
Ali Sobhanmanesh ◽  
Ramli Nazir ◽  
Nader SaadatkhaH
Keyword(s):  
Deformation Behavior ◽  
Three Dimension ◽  
Crust Layer ◽  
Staged Construction ◽  
Weathered Crust ◽  
Dimension 2 ◽  
Embankment Height ◽  
The Stability ◽  
Positive Effect ◽  
Surface Crust

his paper attempts to evaluate the effect of surface crust layer on the stability and deformation behavior of embankment. A full-scale case history trial embankment constructed on Muar flat in the valley of the Muar River in Malaysia was modeled and analyzed. The Muar trial embankment was simulated in two- and three-dimension (2-D and 3-D) utilizing finite element programs PLAXIS 2-D AND PLAXIS 3-D FOUNDATION, using staged-construction procedure. Sensitivity analysis was performed by varying the thickness of weathered crust layer beneath the embankment fill, i.e., three models of embankment with no surface crust, 1 m surface crust and 2 m surface crust layer. Predictions were made for the vertical and the horizontal displacements of the embankment. Factor of safety for each meter increase in the embankment height was defined until the failure is reached. It is concluded that the bearing capacity of the ground and the deformation behavior of the embankment were sensitive to the thickness of the weathered crust layer. The surface crust layer has a positive effect on the stability of the embankment and consequently reduces the settlement and increases the failure height of the embankment fill up to 37%.

scholarly journals Inhibition or Facilitation? Contrasted Inter-Specific Interactions in Sphagnum under Laboratory and Field Conditions

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1554
Author(s):  
Chao Liu ◽  
Zhao-Jun Bu ◽  
Azim Mallik ◽  
Yong-Da Chen ◽  
Xue-Feng Hu ◽  
...  
Keyword(s):  
Field Experiment ◽  
Species Interactions ◽  
Laboratory Experiments ◽  
Resource Competition ◽  
Specific Interactions ◽  
Interaction Type ◽  
Negative Effects ◽  
Experiment Data ◽  
The Stability ◽  
Positive Effect

In a natural environment, plants usually interact with their neighbors predominantly through resource competition, allelopathy, and facilitation. The occurrence of the positive effect of allelopathy between peat mosses (Sphagnum L.) is rare, but it has been observed in a field experiment. It is unclear whether the stability of the water table level in peat induces positive vs. negative effects of allelopathy and how that is related to phenolic allelochemical production in Sphagnum. Based on field experiment data, we established a laboratory experiment with three neighborhood treatments to measure inter-specific interactions between Sphagnum angustifolium (Russ.) C. Jens and Sphagnum magellanicum Brid. We found that the two species were strongly suppressed by the allelopathic effects of each other. S. magellanicum allelopathically facilitated S. angustifolium in the field but inhibited it in the laboratory, and relative allelopathy intensity appeared to be positively related to the content of released phenolics. We conclude that the interaction type and intensity between plants are dependent on environmental conditions. The concentration of phenolics alone may not explain the type and relative intensity of allelopathy. Carefully designed combined field and laboratory experiments are necessary to reveal the mechanism of species interactions in natural communities.

SHELL MATERIAL'S PERFORMANCE OF THE MICROCAPSULE FOR ELECTROLYTIC CO-DEPOSITION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3124-3130 ◽  
Author(s):  
HUI CONG LIU ◽  
XIU QING XU ◽  
WEI PING LI ◽  
YAN HONG GUO ◽  
LI-QUN ZHU
Keyword(s):  
Composite Coating ◽  
Methyl Cellulose ◽  
Water Vapor Permeability ◽  
Core Material ◽  
Vapor Permeability ◽  
Shell Material ◽  
The Core ◽  
Surface Performance ◽  
The Stability ◽  
Positive Effect

The shell material of microcapsules has an important effect on the electrolytic co-deposition behavior, the release of core material and the surface performance of composite coating. This paper discussed the tensile property and the stability of three shell materials including polyvinyl alcohol (PVA), gelatin and methyl cellulose (MC). It is found that these three shell materials have good mechanical strength and flexibility which are favorable to electrolytic co-deposition and stability of microcapsules in composite coating and that MC has well permeability and porosity which has a positive effect on the release of the core material in composite coating. Moreover, the study of the thermal properties and water vapor permeability of the three shell materials showed that their permeability improved with increase of temperature and humidity. In addition, the composite copper coating containing microcapsules with PVA, gelatin or MC as shell material was prepared respectively.

scholarly journals The Effect of Ginger on the Invasion and Migration of Glioma Cells

2020 ◽  
pp. 38-43
Author(s):  
Manar Zraikat ◽  
Munir Gharaibeh ◽  
Tasneem Alshelleh
Keyword(s):  
Cell Line ◽  
Tumour Progression ◽  
Glioma Cells ◽  
Three Dimension ◽  
Scratch Assay ◽  
Invasion And Migration ◽  
Invasion Model ◽  
Dimension 2 ◽  
And Migration ◽  
U87 Cells

Background: This work studies the effect of different concentrations of soaked ginger on the ability of the U87 glioma cells to invade collagen in a three dimension (3 D) invasion model and compare it with its effect on the ability of the same cell line to migrate in two-dimension (2 D) scratch assay. Methods: The hanging drop spheroids in 3D invasion assay were used to investigate the in invasion of the U87 cells. The 2D scratch assay was used to investigate the migration of the same cell line. Results: Gradual effect of the soaked ginger was noticed on the inhibition of the invasion of U87 in collagen and on the inhibition of the migration of the same cell line in scratch assay. Conclusion: The results in this article are promising and encourage further studies to investigate the effect of ginger active ingredients on tumour progression.

scholarly journals Impact of Covid-19 on banking business

2021 ◽  
Vol 18 (2) ◽  
pp. 79-90
Author(s):  
Marijana Joksimović ◽  
Jozefina Beke-Trivunac
Keyword(s):  
Credit Risk ◽  
World Health Organization ◽  
Banking System ◽  
World Health ◽  
Global Level ◽  
The World ◽  
Banking Business ◽  
The Stability ◽  
Health Organization ◽  
Positive Effect

The Covid-19 virus pandemic, declared in 2020 by the World Health Organization, has a very large impact on banking business around the world. The most significant problem is the growth of credit risk and the huge growth of demand for liquid assets. The crisis has also increased the risks associated with the digitalization of banking business and brought new risks posed by the work of employees from home. The timely reaction of regulatory authorities, at the global level, and the willingness of the monetary and fiscal authorities of all countries to cooperate have shown a very positive effect on the stability of the banking system.

Numerical analysis of strengthening by rockfill embankments on an upstream tailings dam

2013 ◽  
Vol 50 (4) ◽  
pp. 391-399 ◽  
Author(s):  
Linda Ormann ◽  
Muhammad Auchar Zardari ◽  
Hans Mattsson ◽  
Annika Bjelkevik ◽  
Sven Knutsson
Keyword(s):  
Finite Element ◽  
Minimum Cost ◽  
Tailings Dam ◽  
Consolidation Process ◽  
Downstream Side ◽  
Pore Pressures ◽  
Staged Construction ◽  
The Stability ◽  
Excess Pore Pressures ◽  
Excess Pore

The consolidation process could be slow in an upstream tailings dam; therefore, the stability can reduce due to an increase in excess pore pressures when the dam is raised. The safety of the dam can be enhanced by constructing rockfill berms on the downstream side. This paper presents a case study on the strengthening of an upstream tailings dam with rockfill berms. The finite element analyses were performed for modelling the staged construction of the dam and for optimizing the volume of the rockfill berms. The dam was raised in 11 stages; each stage consisting of a raising phase and a consolidation phase. The study shows that the slope stability of the dam reduced due to an increase of excess pore pressures during the raising phase. The stability of the dam was successfully improved by utilizing rockfill berms as supports on the downstream side. A technique has been presented to minimize the volume of the rockfill berms so that the required stability can be achieved at minimum cost. This paper shows that the finite element method can be a useful tool for modelling the consolidation behaviour of an upstream tailings dam and minimizing the volume of the rockfill berms that may be needed to maintain the stability of the dam during staged construction.

Vegetation dynamics drive the evolution of soil aggregate stability during the first 14,000 years of soil development in the Swiss alps

2021 ◽  
Author(s):  
Konrad Greinwald ◽  
Tobias Gebauer ◽  
Ludwig Treuter ◽  
Victoria Kolodziej ◽  
Alessandra Musso ◽  
...  
Keyword(s):  
Vegetation Dynamics ◽  
Plant Cover ◽  
Aggregate Stability ◽  
Root Traits ◽  
Soil Aggregate ◽  
Swiss Alps ◽  
Soil Aggregate Stability ◽  
Alpine Regions ◽  
The Stability ◽  
Positive Effect

<p><strong>Aims:</strong></p><p>The stability of hillslopes is an essential ecosystem service, especially in alpine regions with soils prone to erosion. One key variable controlling hillslope stability is soil aggregate stability. However, there is comparatively little knowledge about how vegetation dynamics affect soil aggregate stability during landscape evolution.</p><p><strong>Methods:</strong></p><p>We quantified soil aggregate stability by determining the Aggregate Stability Coefficient (ASC), which was developed for stone-rich soils. To reveal how hillslope aging and corresponding changes in vegetation affect the evolution of ASC, we measured plant cover, diversity, and root traits along two chronosequences in the Swiss Alps.</p><p><strong>Results:</strong></p><p>We found a significant positive effect of vegetation cover and diversity on ASC that was mediated via root traits. These relationships, however, developed in a time-depended manner: At young terrain ages, above- and belowground vegetation characteristics had a stronger effect on aggregate stability than species diversity, whereas these relationships were weaker at older stages.</p><p><strong>Conclusions:</strong></p><p>Our findings highlight the importance of vegetation dynamics for the evolution of aggregate stability and enhance our understanding of processes linked to hillslope stabilization, which is a key priority to avoid further soil degradation and connected risks to human safety in alpine areas.</p>

Ammonia volatilization during storage of cattle and pig slurry: effect of surface cover

1993 ◽  
Vol 121 (1) ◽  
pp. 63-71 ◽  
Author(s):  
S. G. Sommer ◽  
B. T. Christensen ◽  
N. E. Nielsen ◽  
J. K. Schjφrring
Keyword(s):  
Convective Transport ◽  
Wind Tunnels ◽  
Pig Slurry ◽  
Surface Layers ◽  
Cereal Straw ◽  
Natural Surface ◽  
Crust Layer ◽  
Montmorillonitic Clay ◽  
Surface Crust ◽  
Effect Of Surface

SUMMARYGaseous NH3 losses from pig and cattle slurry stored in eight storage tanks were measured simultaneously using wind-tunnels. The slurry was either stirred weekly (uncovered), or was allowed to develop a natural surface crust. Oil, peat, chopped cereal straw, PVC foil, leca® (pebbles of burned montmorillonitic clay) and a lid were tested as additional covers. Convective transport of ammonium to the surface layers caused NH3 volatilization losses of 3–5 g NH3-N/m2 per day from the stirred, uncovered tanks. The loss of NH3 from the stirred slurry was related to air temperature. The development of a natural surface crust reduced NH3 losses to 20% of those from stirred slurry. NH3 losses from slurry not developing a natural surface crust layer and left undisturbed were similar to the losses from stirred slurry. A 15 cm layer of straw was as effective as a surface crust layer in reducing NH3 losses. In one experiment, cracks developed in the oil cover and losses were therefore only reduced to 50% of those of uncovered slurry. Apart from this experiment, NH3 losses from slurry covered with oil, leca®, peat and foil were small.

Advances in Ambient Temperature Creep Deformation Behavior of Two-Phase Titanium Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 779-784 ◽  
Author(s):  
A. Jaworski ◽  
Sreeramamurthy Ankem
Keyword(s):  
Titanium Alloys ◽  
Creep Deformation ◽  
Deformation Behavior ◽  
Creep Resistance ◽  
Volume Fraction ◽  
Beta Phase ◽  
Two Phase ◽  
Number Of Factors ◽  
Strength Difference ◽  
The Stability

In recent years, significant advances have been made in regard to the creep deformation behavior of two phase titanium alloys. It has been shown that the creep resistance depends on a number of factors, including the shape of the component phases, the strength difference between the phases, and the stability of the beta phase. For example, in two-phase materials with a similar volume fraction and morphology of phases, if the beta phase is less stable, then the creep resistance is lower. These developments will be reviewed and the reasons for such effects will be suggested.

Stability of Controlled Road Vehicles: A Preliminary Fundamental Study

2015 ◽  
Author(s):  
Fabio della Rossa ◽  
Massimiliano Gobbi ◽  
Giampiero Mastinu ◽  
Carlo Piccardi ◽  
Giorgio Previati
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Preliminary Investigation ◽  
Basin Of Attraction ◽  
Lateral Acceleration ◽  
Steering Wheel ◽  
Vehicle Speed ◽  
Vehicle Model ◽  
The Stability ◽  
Positive Effect

A comparison of the lateral stability behaviour between an autonomous vehicle, a vehicle with driver and a vehicle without driver (fixed steering wheel) is made by introducing a simple mathematical model of a vehicle running on even road. The mechanical model of the vehicle has two degrees of freedom and the related equations of motion contain the nonlinear tyre characteristics. The driver is described by a well-known model proposed in the literature. The autonomous vehicle has a virtual driver (robot) that behaves substantially like a human, but with its proper reaction time and gain. The road vehicle model has been validated. The study of vehicle stability has to be based on bifurcation analysis and a preliminary investigation is proposed here. The accurate computation of steady-state equilibria is crucial to study the stability of the three kinds of vehicles here compared. The stability of the bare vehicle without driver (fixed steering wheel) is studied in a rather complete way referring to a number of combinations of tyre characteristics. The (known) conclusion is that the understeering vehicle is stable at each lateral acceleration level and at each vehicle speed. The additional (partially unknown) conclusion is that the vehicle (model) with degradated tyres may exhibit a huge number of different bifurcations. The driver has many effects on the stability of the vehicle. One positive effect is to eliminate the many possible different equilibria of the bare vehicle and keep active one single equilibrium only. Another positive effect is to broaden the basin of attraction of stable equilibria (at least at relatively low speed). A negative effect is that, even for straight running, the driver seem introducing a subcritical Hopf bifurcation which limits the maximum forward speed of some understeering vehicles (that could run faster with fixed steering wheel). Both the mentioned positive and negative effects appear to be applicable to autonomous vehicles as well. Further studies could be useful to overcome the limitations on the stability of current autonomous vehicles that have been identified in the present research.

Effects of Rhamnolipids on Enzymatic Hydrolysis of Bamboo Biomass and Mechanism

2020 ◽  
Vol 14 (4) ◽  
pp. 453-460
Author(s):  
Ruyi Sha ◽  
Zhan Yu ◽  
Zhenzhen Wang ◽  
Edwin Menledy Gbor ◽  
Ligang Jiang ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Fluorescence Probe ◽  
Economic Losses ◽  
Dilute Acid ◽  
Site Of Action ◽  
The Stability ◽  
Surface Modified ◽  
Hydrolysis Of ◽  
Positive Effect

The lignin present in lignocellulose seriously affects the efficiency of cellulose enzymatic hydrolysis. In addition, lignin adsorbs high-cost cellulase, causing greater economic losses. Lignin can also disturb the site of action of cellulase and reduce the efficiency of hydrolysis. Therefore, if lignin is removed or surface modified before cellulose enzymatic hydrolysis, the enzymatic hydrolysis efficiency of lignocellulosic biomass will be greatly improved. In this paper, the cellulose enzymatic properties of bamboo biomass being treated with dilute acid and alkaline under the intervention of biosurfactant rhamnolipid were evaluated. The effects of rhamnolipids on the adsorption characterization of cellulose on pretreated bamboo were studied. Besides, the inter-communication between rhamnolipids and cellulose was investigated by fluorescence probe. The results showed that rhamnolipids could have a positive effect on the enzymatic hydrolysis of bamboo biomass by reducing the non-productive adsorption of cellulase on the surface of lignocellulose. The outcome illustrated that cellulase could be combined with rhamnolipids micelles, participating in the formation of rhamnolipids micelles, thereby increasing the internal hydrophobicity of the micelles, but could not change the properties of rhamnolipids micelles higher than one CMC (Critical Micelle Concentration). It can be seen that the interaction between rhamnolipids and cellulase is beneficial to enhance the stability and enzymatic activity of cellulase, thereby improving the enzymatic hydrolysis efficiency of cellulose in biomass. Based on these results, a theoretical knowledge about the mechanism of enhancing the enzymatic hydrolysis efficiency of lignocellulose by biosurfactants rhamnolipids is provided.

Sign in / Sign up

Export Citation Format

Share Document