Influence of Bacteria Pseudomonas fluorescens on the Properties of Latvian Clay

2014 ◽  
Vol 604 ◽  
pp. 208-211
Author(s):  
Maris Rundans ◽  
Ingunda Sperberga ◽  
Gaida Sedmale ◽  
Dagnija Vecstaudza ◽  
Olga Muter
Keyword(s):  
Soil Properties ◽  
Rheological Properties ◽  
Pseudomonas Fluorescens ◽  
Extracellular Polymeric Substances ◽  
Clay Soil ◽  
Atterberg Limits ◽  
Mineral Particles ◽  
Ft Ir ◽  
Growth Of Bacteria

Wide varieties of bacteria are able to produce extracellular polymeric substances (EPS) which are mostly composed of polysaccharides. It is suggested that EPS substances can alter certain clay soil properties due to their ability to adhere to the surface of mineral particles. Most common used microorganisms by the researchers for this purpose are of either genus Bacillus or genus Pseudomonas. In this study growth of bacteria P. fluorescens AM PS11 culture in locally obtained clay is studied for the purpose of establishing their influence on rheological properties of clay. An attempt to evaluate it has been made using FT-IR and XRD. Change in plasticity of clay using Atterberg limits method and coefficient of drying sensitivity has also been determined.

scholarly journals Influence of biopolymers on the rheological properties of seafloor sediments and the runout behavior of submarine debris flows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Kameda ◽  
Hamada Yohei
Keyword(s):  
Rheological Properties ◽  
Debris Flows ◽  
Extracellular Polymeric Substances ◽  
Flow Behavior ◽  
Mass Movement ◽  
Rheological Parameters ◽  
Natural Environments ◽  
Natural Systems ◽  
Chemical Conditions ◽  
Seafloor Sediments

AbstractSubmarine debris flows are mass movement processes on the seafloor, and are geohazards for seafloor infrastructure such as pipelines, communication cables, and submarine structures. Understanding the generation and run-out behavior of submarine debris flows is thus critical for assessing the risk of such geohazards. The rheological properties of seafloor sediments are governed by factors including sediment composition, grain size, water content, and physico-chemical conditions. In addition, extracellular polymeric substances (EPS) generated by microorganisms can affect rheological properties in natural systems. Here we show that a small quantity of EPS (~ 0.1 wt%) can potentially increase slope stability and decrease the mobility of submarine debris flows by increasing the internal cohesion of seafloor sediment. Our experiments demonstrated that the flow behavior of sediment suspensions mixed with an analogue material of EPS (xanthan gum) can be described by a Herschel–Bulkley model, with the rheological parameters being modified progressively, but not monotonously, with increasing EPS content. Numerical modeling of debris flows demonstrated that the run-out distance markedly decreases if even 0.1 wt% of EPS is added. The addition of EPS can also enhance the resistivity of sediment to fluidization triggered by cyclic loading, by means of formation of an EPS network that binds sediment particles. These findings suggest that the presence of EPS in natural environments reduces the likelihood of submarine geohazards.

scholarly journals An Experimental Study on the Effect of Tire Powder on the Geotechnical Properties of Clay Soils

2018 ◽  
Vol 4 (3) ◽  
pp. 594 ◽  
Author(s):  
Davood Akbarimehr ◽  
Esmael Aflaki
Keyword(s):  
Clay Soil ◽  
Geotechnical Properties ◽  
Atterberg Limits ◽  
Clay Soils ◽  
Positive Effects ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Problematic Soils ◽  
Geotechnical Problems ◽  
Comprehensive Study

With respect to the increasing production of tire wastes, the use of these wastes as an additive in civil engineering has always gained attentions of researchers due to their positive effects on material properties and reduction of environmental problems. Clay soils, as problematic soils, have always caused geotechnical problems including high Atterberg limits and consequently low workability. Tire powder, as one of the products of tire wastes, lacks clay cohesion and it can be effective in altering the plasticity of clay soils. As no comprehensive study has been conducted in this regard specifically on Tehran clay soil yet, this research studies experimentally the effect of adding different percentages of tire powder to clay soil at the Atterberg limits of clay soils with two different types of plasticity. More over according to previous studies, the effect of tire powder on other geotechnical properties of clay soils and the advantages and disadvantages of using tire powder in clay soils are discussed. The results indicate that addition of tire powder to clay soils has positive effects on reducing the Atterberg limits, increasing efficiency, and improving resistance, permeability, swelling reduction, and settlement properties, and reducing soil density and it can be used as an additive in improving clay soils.

Use of FT-IR, FT-Raman and thermal analysis to evaluate the gel formation of curdlan produced by Agrobacterium sp. IFO 13140 and determination of its rheological properties with food applicability

2017 ◽  
Vol 232 ◽  
pp. 369-378 ◽  
Author(s):  
Camila Sampaio Mangolim ◽  
Thamara Thaiane da Silva ◽  
Vanderson Carvalho Fenelon ◽  
Adriane do Nascimento ◽  
Francielle Sato ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Rheological Properties ◽  
Gel Formation ◽  
Ft Ir ◽  
Ft Raman

scholarly journals Soil-concrete for use in the 3D printers in the construction of buildings and structures

2018 ◽  
Vol 245 ◽  
pp. 03002 ◽  
Author(s):  
Petr Iubin ◽  
Lubov Zakrevskaya
Keyword(s):  
Rheological Properties ◽  
Cement Paste ◽  
Clay Soil ◽  
Cement Composite ◽  
Cement Composites ◽  
Test Results ◽  
Flow Table ◽  
Key Factor ◽  
3D Printers ◽  
The Cost

Nowadays, the construction of cement composite using 3D printers is considered one of the most promising methods of automation of building processes. However, the compositions of cement composites have several disadvantages, such as high cost, short workability and etc. It has been suggested that clay soil as an additive will help to solve these problems partially. The aim of the work is development the cement compositions with clay soil, for use in 3D printers to construction. The composite consists of cement paste with clay soil and additives. To study printability of a composite the rheological properties in a fresh state were studied. The study of the rheological properties of composites was carried out using a flow table test for mortar. The key factor for determining the suitability of the composite for printing was accepted the diameter of the cone after shaking. The test results showed the possibility of replacing cement paste with clay soil up to 25% which leads to a reduction in the cost and an increase in printability with a slight decrease in the strength of the obtained material to 7%. Utilizing of soil from the construction site provides maximum economic efficiency of the material application.

Delineation of management zones with measurements of soil apparent electrical conductivity in the southeastern pampas

2013 ◽  
Vol 93 (2) ◽  
pp. 205-218 ◽  
Author(s):  
Nahuel Raúl Peralta ◽  
José Luis Costa ◽  
Mónica Balzarini ◽  
Hernán Angelini
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Stepwise Regression ◽  
Clay Soil ◽  
Crop Yields ◽  
Management Strategies ◽  
Site Specific ◽  
Management Zones ◽  
Apparent Electrical Conductivity ◽  
Specific Management

Peralta, N. R., Costa, J. L., Balzarini, M. and Angelini, H. 2013. Delineation of management zones with measurements of soil apparent electrical conductivity in the southeastern pampas. Can. J. Soil Sci. 93: 205–218. Site-specific management demands the identification of subfield regions with homogeneous characteristics (management zones). However, determination of subfield areas is difficult because of complex correlations and spatial variability of soil properties responsible for variations in crop yields within the field. We evaluated whether apparent electrical conductivity (ECa) is a potential estimator of soil properties, and a tool for the delimitation of homogeneous zones. ECamapping of a total of 647 ha was performed in four sites of Argentinean pampas, with two fields per site composed of several soil series. Soil properties and ECawere analyzed using principal components (PC)–stepwise regression and ANOVA. The PC–stepwise regression showed that clay, soil organic matter (SOM), cation exchange capacity (CEC) and soil gravimetric water content (θg) are key loading factors, for explaining the ECa(R2≥0.50). In contrast, silt, sand, extract electrical conductivity (ECext), pH values and [Formula: see text]-N content were not able to explain the ECa. The ANOVA showed that ECameasurements successfully delimited three homogeneous soil zones associated with spatial distribution of clay, soil moisture, CEC, SOM content and pH. These results suggest that field-scale ECamaps have the potential to design sampling zones to implement site-specific management strategies.

Extraction of extracellular polymeric substances from the acidophilic bacterium Acidiphilium 3.2Sup(5)

2009 ◽  
Vol 59 (10) ◽  
pp. 1959-1967 ◽  
Author(s):  
J. M. Tapia ◽  
J. A. Muñoz ◽  
F. González ◽  
M. L. Blázquez ◽  
M. Malki ◽  
...  
Keyword(s):  
Microbial Fuel Cells ◽  
Extracellular Polymeric Substances ◽  
Ion Exchange Resin ◽  
Before And After ◽  
Acidophilic Bacterium ◽  
Ft Ir ◽  
Promising Application ◽  
Microscopy Techniques ◽  
Graphite Rods ◽  
Cellular Lysis

Extraction of extracellular polymeric substances (EPS) from Acidiphilium 3.2Sup(5) was investigated using five methods: EDTA, NaOH, ion exchange resin, heating and centrifugation. The bacterium studied presents promising application in microbial fuel cells (MFCs). The degree of cellular lysis provoked by each method was determined by UV-visible spectroscopy of cultures before and after EPS extraction. In addition, two electron microscopy techniques (TEM and SEM) were employed to determine the degree of attachment and the growth of the biofilm overtime on two solid supports: carbon fibre cloth and graphite rods. The main constituents of the EPS extracted by all methods were proteins and carbohydrates, as confirmed by FT-IR analysis, showing the major presence of carboxylic, hydroxylic and amino groups. The greater extractions of EPS were obtained using EDTA. This method also produced a less degree of cellular lysis. Furthermore, both the amount and the chemical composition of EPS strongly depended on the extraction method used.

Sign in / Sign up

Export Citation Format

Share Document