Experimental study on penetration of bentonite grout through granular soils

2015 ◽  
Vol 52 (11) ◽  
pp. 1850-1860 ◽  
Author(s):  
Chadi S. El Mohtar ◽  
Jisuk Yoon ◽  
May El-Khattab
Keyword(s):  
Yield Stress ◽  
Apparent Viscosity ◽  
Experimental Parameter ◽  
Engineering Properties ◽  
High Yield ◽  
Granular Soils ◽  
Permeation Grouting ◽  
Experimental Conditions ◽  
Penetration Length ◽  
Bentonite Grout

Permeation grouting using bentonite grouts is one of the effective methods to improve the engineering properties of granular soils. However, the low penetrability of bentonite grouts into soils limits their practical application in permeation grouting. This study presents a new approach to control the penetration length of bentonite grouts through granular soils using an ionic additive, sodium pyrophosphate (SPP). It is hypothesized that the chemical modification changes both rheological and physicochemical properties of the bentonite grout, and thus affects its penetration length through soils. The rheological properties (yield stress and apparent viscosity) of bentonite grouts with weight ratios (ratio of water to dry bentonite, W/B) of 19, 12.3, 9, and 7.3 were controlled by the addition of 1%–4% SPP by weight of dry bentonite. The bentonite grouts were also injected into sand columns prepared at various experimental conditions to evaluate the effect of each experimental parameter on their penetration lengths. The results show that the penetration length of bentonite grouts decreases with a decrease in W/B ratio and an increase in yield stress and apparent viscosity. Moreover, the penetration length increases with the increase of the normalized effective grain size and injection pressure, but the increase of fines content reduces the penetration length of the grouts. While the existing analytical equation produces good agreement with the measured penetration lengths for the grouts having high yield stress (>26 Pa), it significantly overestimates the penetration lengths of the SPP modified bentonite grouts due to filtration (especially, the grouts having low yield stress and low W/B ratios). Therefore, a new empirical correlation is proposed to predict the penetration length of the bentonite grouts based on filtration and rheological blocking.

scholarly journals Identification of the most suitable reference gene for gene expression studies with development and abiotic stress response in Bromus sterilis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Madhab Kumar Sen ◽  
Kateřina Hamouzová ◽  
Pavlina Košnarová ◽  
Amit Roy ◽  
Josef Soukup
Keyword(s):  
Reference Gene ◽  
Herbicide Resistance ◽  
Reference Genes ◽  
Gene Selection ◽  
High Yield ◽  
Suitable Reference Gene ◽  
Grass Species ◽  
Experimental Conditions ◽  
Qrt Pcr ◽  
Suitable Reference

AbstractBromus sterilis is an annual weedy grass, causing high yield losses in winter cereals. Frequent use of herbicides had led to the evolution of herbicide resistance in this species. Mechanisms underlying herbicide resistance in B. sterilis must be uncovered because this problem is becoming a global threat. qRT-PCR and the next-generation sequencing technologies can elucidate the resistance mechanisms. Although qRT-PCR can calculate precise fold changes, its preciseness depends on the expression of reference genes. Regardless of stable expression in any given condition, no gene can act as a universal reference gene. Hence, it is necessary to identify the suitable reference gene for each species. To our knowledge, there are no reports on the suitable reference gene in any brome species so far. Thus, in this paper, the stability of eight genes was evaluated using qRT-PCR experiments followed by expression stability ranking via five most commonly used software for reference gene selection. Our findings suggest using a combination of 18S rRNA and ACCase to normalise the qRT-PCR data in B. sterilis. Besides, reference genes are also recommended for different experimental conditions. The present study outcomes will facilitate future molecular work in B. sterilis and other related grass species.

Electrorheological fluid with an extraordinarily high yield stress

2002 ◽  
Vol 80 (5) ◽  
pp. 888-890 ◽  
Author(s):  
Yuling Zhang ◽  
Kunquan Lu ◽  
Guanghui Rao ◽  
Yu Tian ◽  
Shaohua Zhang ◽  
...  
Keyword(s):  
Yield Stress ◽  
Electrorheological Fluid ◽  
High Yield ◽  
High Yield Stress

Impact of Molecular Chain Structure of Suspension Phase on Giant Electrorheological Performance

2022 ◽  
Author(s):  
Hanqi Xu ◽  
Jinbo Wu ◽  
Yaying Hong ◽  
Weijia Wen
Keyword(s):  
Yield Stress ◽  
Chain Length ◽  
Colloidal Stability ◽  
Chain Structure ◽  
Solid Particles ◽  
High Yield ◽  
Suspension Stability ◽  
Chain Lengths ◽  
The Impact ◽  
Oil Particles

Abstract We demonstrate the impact of diester structure, in particular the alkyl chain length and branching structure, on the giant electrorheological (GER) effect and suspension stability. The existence of oil-particles interaction is of critical importance to induce the GER effect. To quantify GER performance and colloidal stability, we examine the yield stress, current density, field-off viscosity and sedimentation ratio with respect to the variation of chain length and branching structure. The oil-particles interaction is quantitatively analyzed by investigating the cluster size of particles in different diesters by a multiple light scattering analyzer, along with the wettability of different chain lengths of diesters and solid particles by the Washburn method. Our results indicate that long chain lengths favor the formation of particle agglomerates, thereby enhancing the GER effect (such as high yield stress). The attachment of branches on diester causes the formation of electronic correlation between branches and main chain, depending on the position of branches located, and hence results in superior GER performance and favorable suspension stability. An optimal GER fluid constituted by bis(2-ethylhexyl) sebacate is acquired with the achieved yield stress of 113 kPa at electric field strength of 4 kV/ mm and the prominent integrated GER properties.

Effect of Superplasticizers on the Workability of Concrete as Evident from Apparent Viscosity, Yield Stress and Zeta-Potential

1992 ◽  
Vol 289 ◽  
Author(s):  
R.I.A. Malek ◽  
D.M. Roy
Keyword(s):  
Yield Stress ◽  
Apparent Viscosity ◽  
Fresh Concrete ◽  
Low Cost ◽  
Aggregate Size ◽  
Unit Weight ◽  
Microstructural Development ◽  
Concrete Durability ◽  
Concrete Technology ◽  
The Individual

AbstractModem concrete technology projections indicate a great expansion in low-cost and time efficient construction. Mixture designers will likely be more concerned with the developments in concrete making materials. Among those is the effective use of chemical admixtures and superplasticizers which will lower the water to cement ratio but will still give a dense workable concrete. An investigation of the workability of fresh concrete and the effect of superplasticizers should, therefore, constitute an essential part of modem concrete durability studies.In this paper we report part of the work on rheological properties of fresh concrete. Various concrete samples covering a range of compositions that are commonly used for highway pavements are prepared. The proportioning parameters are: cement content, aggregate size, gradation and sphericity-roundness, and water and superplasticizer contents. The individual solid ingredients were characterized and the fresh concrete properties were assessed by the slump, two-point workability (Tattersall's) apparatus, air pressure and unit weight methods. The effects of superplasticizer on the apparent viscosity and yield stress of concrete are discussed and the relevance of the findings for field applications (handling of fresh concrete) are discussed. Also discussed are the implications for microstructural development.

scholarly journals Asymmetric synthesis of a high added value chiral amine using immobilized ω-transaminases

2019 ◽  
Vol 15 ◽  
pp. 60-66 ◽  
Author(s):  
Antonella Petri ◽  
Valeria Colonna ◽  
Oreste Piccolo
Keyword(s):  
Enantiomeric Excess ◽  
Practical Interest ◽  
Continuous System ◽  
Immobilized Enzymes ◽  
Added Value ◽  
High Yield ◽  
Experimental Conditions ◽  
Chiral Amine ◽  
Heterocyclic Molecules ◽  
One Step

Chiral N-heterocyclic molecules and in particular compounds with an amino functional group such as 3-aminopiperidine are valuable intermediates for the production of a large number of bioactive compounds with pharmacological properties. In this paper, the synthesis of both enantiomers of 3-amino-1-Boc-piperidine by amination of the prochiral precursor 1-Boc-3-piperidone using immobilized ω-transaminases (TAs-IMB), isopropylamine as amine donor and pyridoxal-5’-phosphate (PLP) as cofactor is described. Compared to other methods, the present approach affords the target compound in just one step with high yield and high enantiomeric excess starting from a commercial substrate. The reaction was carried out by using different commercially available immobilized enzymes, evaluating the catalytic activity and the enantioselectivity under different experimental conditions. Re-use of the most efficient enzyme was performed both in batch and in a semi-continuous system. The selected biocatalyst showed good stability under the reaction conditions providing consistent results in terms of conversion and enantiomeric excess after several cycles. The reported results may be of practical interest in view of the development of this sustainable approach to an industrial scale.

Development of a double magnetic circuit yield stress measurement device for magnetorheological fluid

2016 ◽  
Vol 28 (10) ◽  
pp. 1249-1259 ◽  
Author(s):  
Xiang-Fan Wu ◽  
Xing-Ming Xiao ◽  
Zu-Zhi Tian ◽  
Fei Chen ◽  
Jian Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Yield Stress ◽  
Magnetic Circuit ◽  
Stress Measurement ◽  
Magnetorheological Fluid ◽  
High Yield ◽  
Magnetic Field Measurement ◽  
Measurement Device ◽  
Accuracy And Repeatability ◽  
The Magnetic Field

On the basis of shear working mode of magnetorheological fluid, in this article, a novel temperature controllable yield stress measurement device is designed, and the double magnetic circuit structure and the heating structure are proposed. And then, the magnetic field and temperature field of the measurement device are simulated, respectively, by the finite element method. Furthermore, several experiments are carried out to evaluate the magnetic field, measurement precision, and repeatability of the self-designed device. The results indicate that the proposed measurement device has uniform magnetic field distribution and controllable temperature and also has high yield stress testing accuracy and repeatability.

Extensive application of TMCP steel plates to ship hulls: 40 kgf/mm2 class high yield stress steel

1988 ◽  
Vol 1 (3) ◽  
pp. 219-243 ◽  
Author(s):  
Susumu Machida ◽  
Hiroshige Kitada ◽  
Hiroshi Yajima ◽  
Akinobu Kawamura
Keyword(s):  
Yield Stress ◽  
Steel Plates ◽  
High Yield ◽  
Ship Hulls ◽  
High Yield Stress

4,5-Seco-4,6-cyclosteroids. III. Observations on the course of reductive rearrangement of 6β-Bromo-4β,5-epoxy-5β-cholestan-3β-ol

1969 ◽  
Vol 22 (4) ◽  
pp. 807 ◽  
Author(s):  
DJ Collins ◽  
JJ Hobbs ◽  
RJ Rawson
Keyword(s):  
Hydrogen Bromide ◽  
High Yield ◽  
Lithium Aluminium Hydride ◽  
Experimental Conditions ◽  
Lithium Aluminium ◽  
Reaction Proceeds ◽  
Derivatives Of

It has been shown that reductive rearrangement of 6β-bromo-4β,5-epoxy- 5β-cholestan-3β-ol (I) to 4,5-seco-4,6-cycle-6β-cholestane-3β,5α-diol (IXa) with lithium aluminium hydride in tetrahydrofuran proceeds via 6β-bromo-5β-cholestane-3β,5-diol (IIa). Relevant reactions of the latter and the corresponding 3-ketone are discussed. ��� Similar conversion of the 3-epimer of (I) into 4,5-seco-4,6-cyclo- 6β-cholestane-3α,5α-diol (XIIIa) in high yield indicates that reductive rearrangement of the 6β-bromo-5β-hydroxy moiety proceeds without participation of the 3-aluminate complex. Some derivatives of (XIIIa) are described. ��� Experimental conditions required for the conversion of (I) into (IXa) are defined. ��� Combined evidence indicates that the reaction proceeds in a concerted manner by essentially base-catalysed, 1,3-elimination of hydrogen bromide from diol (IIa) with 4,5-bond migration to give the formal intermediate 3β-hydroxy-4,5-seco-4,6-cyclo-6β-cholestan-5-one (VI), further reduced to (IXa).

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