scholarly journals Impact of the Plate Diameter on the Value of the Pre-Compaction Stress in Soils With Varied Textural Group

2016 ◽  
Vol 20 (3) ◽  
pp. 5-14 ◽  
Author(s):  
Dariusz Błażejczak ◽  
Jan B. Dawidowski
Keyword(s):  
Solid Phase ◽  
Classical Method ◽  
Testing Machine ◽  
Liquid Limit ◽  
Solid Particles ◽  
Degree Of Saturation ◽  
Dry Density ◽  
Stress Curve ◽  
Compaction Stress ◽  
The Impact

AbstractThe objective of the paper was to verify the previously obtained results of research concerning the impact of the plate diameter on the measured value of the pre-compaction stress of silt (NG), in conditions of a wider range of soil types and their initial stage. The research was carried out on samples with a diameter of 100 mm and height of 30 mm produced from the soil material (M) or collected from the subsoil of the selected soils (AWN) with the granulation type of: silt loam, loam, light loam, sandy-clay soil. The following soils properties were determined: the granulation type, density of the solid phase, content of humus and calcium carbonate, reaction, plastic and liquid limit. The properties of samples were described with moisture, dry density of solid particles, porosity of aeration, degree of plasticity and degree of saturation. The samples were loaded with a testing machine with plates with varied diameters. The value of the pre-compaction stress of soil was measured with the method of searching the crossing point of tangents with the secondary stress curve and the original stresses curve (a classical method). It was found out that for samples M with the degree of saturation of 0.40-0.50, the pre-compaction stress does not significantly depend on the plate diameter. For samples M or AWN, with the degree of saturation of 0.64-0.82, the pre-compaction stress significantly depends on the diameter of the plate. A conclusion was formulated that in the research of NG with the method of uniaxial defonnations, the relation of the diameter of the plate (d) to the diameter of the cylinder (D) should be within 0.5 ≤ d/D ≤ 0.8.

The Impact of the Plate Diameter on the Determined Value of the Pre-Compaction Stress of Samples made of Silt Soil

2016 ◽  
Vol 20 (2) ◽  
pp. 5-14
Author(s):  
Dariusz Błażejczak ◽  
Jan B. Dawidowski
Keyword(s):  
Moisture Content ◽  
Humus Content ◽  
Testing Machine ◽  
Liquid Limit ◽  
Solid Particles ◽  
Degree Of Saturation ◽  
Stress Curve ◽  
Compaction Stress ◽  
Group Density ◽  
The Impact

AbstractThe objective of the paper was to investigate the impact of the plate diameter on the value of the measured pre-compaction stress of soil. The investigations were carried out on model samples with 100 mm diameter and 30 mm height made of the silt loam and the percentage moisture content of 13.7 and 21.9%. The following properties of the used material were measured: the granulation group, density of solid particles, humus content, reaction, plastic and liquid limit and the degree of saturation of samples. The samples were loaded with a testing machine using plates with varied diameters: 20, 30, 50, 70, 80, 90, 96, 98 and 99 mm. The pre-compaction stress value was measured with the method of searching for the crossing point of tangents with the secondary stress curve and original stress curve (a classic method). It was found out that for samples with saturation amounting to 13.7% of the moisture content the pre-compaction stress does not significantly depend on the plate diameter. For samples with saturation amounting to 21.9% of the moisture content the pre-compaction stress may significantly depend on the plate diameter. Based on the obtained results a conclusion was made that in the research on the pre-compaction stress with the method of uni-axial deformations, the relation of the plate diameter (d) to the diameter of the cylinder (D) should be within 0.3 ≤ d/D < 0.8.

scholarly journals Impact of Plate Diameter and Sample Height on the Determined Pre-Compaction Value

2017 ◽  
Vol 21 (1) ◽  
pp. 19-28
Author(s):  
Dariusz Błażejczak ◽  
Jan B. Dawidowski
Keyword(s):  
Solid Phase ◽  
Sandy Loam ◽  
Liquid Limit ◽  
Solid Particles ◽  
Dry Density ◽  
Sample Height ◽  
Solid Phase Content ◽  
Stress Curve ◽  
Compaction Stress ◽  
The Impact

Abstract The objective of the paper was to verify previously obtained results of research on the impact of the plate diameter on the determined value of pre-compaction stress of soil (NG) with a wider selection of dimensions of samples. Tests were carried out on samples with a diameter (D) of 100 mm and heights (H) of 30, 50 or 100 mm produced from the soil material (M) or collected (NNS) from subsoil with the granulation group of: silt loam, loam, sandy loam, sandy clay loam. The following soil properties were determined: granulation type, density of the solid phase, content of humus and calcium carbonate, reaction, plastic and liquid limit. Properties of samples were described with moisture, dry density of solid particles, porosity of aeration, degree of plasticity and saturation. Samples were loaded with plates of varied diameters. The NG value was calculated with the method of searching for the crossing point of tangents with the secondary stress curve and the virgin stresses curve (a traditional method). It was stated that the plate diameter (d) and sample height (H) do not influence the measurement results when the relation d/D is within 0.5 ≤ d/D ≤ 0.8 and the ratio D/H equals 2. It is possible to omit the condition d/D in a situation when soil is low cohesive and its degree of moisture is ca. 0.41-0.44.

scholarly journals Impact of Friction on the Uniaxial Soil Sample Compression Process

2017 ◽  
Vol 21 (2) ◽  
pp. 49-58 ◽  
Author(s):  
Dariusz Błażejczak ◽  
Rafał Nowowiejski ◽  
Jan B. Dawidowski
Keyword(s):  
Friction Force ◽  
Solid Phase ◽  
Solid Particles ◽  
Carbonate Content ◽  
Dry Density ◽  
Cylinder Wall ◽  
Friction Forces ◽  
Soil Material ◽  
Sample Height ◽  
The Impact

AbstractThe objective of the research was to determine the impact of the friction force between the cylinder wall and soil on the soil compaction resistance in relation to the sample height and diameter of the compaction plate. Samples with the diameter of (D) 100 mm and heights (H) of 30, 50 or 100 mm made of of soil material collected from subsoil of the selected plastic soils were used. The soil material wasidentified by the following properties: the granulation type, density of the solid phase, humus and calcium carbonate content, reaction, plastic and liquid limit. Properties of the samples were described with moisture, dry density of solid particles, porosity of aeration, plastic degree and saturation. The samples were loaded with plates of varied diameters (dA: 20; 30; 50; 70; 80; 90 and 98 mm) measuring at the same time forces on the main plate (FA) and the bottom one (FB) with the fixed diameter (dB=98 mm). The registered relationships between the forces FA and FB and plate sinkage (samples deformation) were used for determination of the impact of external friction forces (between the cylinder wall and soil) on the compression resistance of soils. It was found out that the participation of the friction force in relation to the height of samples and plate diameter varied from 0 to ca. 70%. It was proved that one may avoid the impact of the plate diameter dA on the measurement of force FA, when the relation dA/D, for samples with the heights of H30 and H50, is respectively within 0.5 ≤ dA/D < 0.8 and 0.5 ≤ dA/D < 0.7.

The Manufacturing of the Bamboo Buffer Packaging Material

2011 ◽  
Vol 328-330 ◽  
pp. 1369-1372 ◽  
Author(s):  
Ye Liu ◽  
Shi Hang Wang
Keyword(s):  
High Efficiency ◽  
Bubble Diameter ◽  
Testing Machine ◽  
Packaging Material ◽  
Impact Testing ◽  
Maximum Acceleration ◽  
Foaming Agents ◽  
Bamboo Pulp ◽  
Stress Curve ◽  
The Impact

At present work, to make cushioning packaging material from the bamboo fibers. Change the time of the surface treatment and the component contents of foaming agents, adhesives, plasticizers, cross-linking agents, etc. to analyze the effects on the foam density, foaming rate, elasticity, and bubble diameter. The best reagent and the optimal ratio of the various components have been identified. Determined the parameter of foaming techniques based on the high efficiency and no polluting foaming mechanism. Experiment with the impact testing machine to obtain the maximum acceleration - static stress curve, dynamic stress - strain curves, dynamic buffer factor - stress curve, Analyzed the dynamic buffer performance on the of changing the drop height and compared with other cushioning material. we know that: at height of 450mm, the product had lower peak acceleration value than EPE and EPS during the stress area of 2.8-5.4kpa, which means the cushioning property of the bamboo pulp product is better at that time.

Numerical Simulation and Test Research on the Wear of Back Blades in Slurry Pumps

2016 ◽  
Author(s):  
Yi Tao ◽  
Shouqi Yuan ◽  
Jianrui Liu ◽  
Fan Zhang ◽  
Jianping Tao
Keyword(s):  
Optimization Design ◽  
Volume Fraction ◽  
Solid Phase ◽  
Wear Test ◽  
Solid Particles ◽  
Particle Model ◽  
Optimized Design ◽  
Trailing Edge ◽  
Blade Number ◽  
The Impact

Back blades are usually assembled on the outside surface of impeller back shroud as a sealing device in centrifugal slurry pumps. The presence of solid particles in slurry leads to an obvious problem about the abrasion of the flow components of pump. Especially, the life of sealing devices, like the back blades, the oil seals and the shaft sleeve, is only a quarter or less of other components. Hence, an important engineering significance lies in the research on the abrasion of back blades. In this paper, a single-stage horizontal type centrifugal pump was chosen as the main study model. The 3D model of the entire flow field was meshed by hexahedral structured grids. Based on the Particle model, which is an Eulerian multiphase method, the internal two-phase flow in the centrifugal slurry pump was simulated by using ANSYS CFX software. Six optimized design cases with the variation of back blades were analyzed to study the influence of vane profile and blade number of back blades on the abrasion characteristic and sealing performance. The main conclusions obtained are as follows: the volume fraction of solid phase achieved by simulation is in good agreement with the test results; the effect of vane profile on the flow of particles in the passages and the pressure on the seal is small; the usage of less back blade number will lower the flow constraint of blades on the particles and increase the area of axial vortex in each single passage, which means that the impact velocity of particles towards the pressure side grows and the pressure on the seal increases significantly. Based on the simulation mentioned above, two better cases were selected and manufactured for trial. Then, a wear test rig was set up to study the wear pattern of impeller during the operation of pump. Through the comparison of these two impellers after the wear test, it is found that: the back blades with the back forward shape can effectively reduce the abrasion of back blades at the pressure sides near the trailing edge; thickening the trailing edge of back blades to increase the life of back blades is feasible in practical application. The optimization design of back blades was preliminarily achieved which could provide some reference for the optimization design of back blades in centrifugal slurry pumps.

scholarly journals Evaluation of Subsoil Compaction of Plastic Soils

2017 ◽  
Vol 21 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Kinga Śnieg ◽  
Dariusz Błażejczak
Keyword(s):  
Soil Compaction ◽  
Small Degree ◽  
Liquid Limit ◽  
Solid Particles ◽  
Dry Density ◽  
Soil Particles ◽  
Particles Size Distribution ◽  
Natural Density ◽  
Made In ◽  
Subsoil Compaction

Abstract The objective of the research was to evaluate soil compaction with selected indexes and to determine the relation between them including results obtained with Proctor’s method. Measurements of penetration resistance and shear vane, dry density of soil particles (ρd) and their moisture were made in layers in the following depths: 25-30, 35-40, 45-50 and 55-60 cm. Moreover, the maximum volumetric density of soil particles, particles size distribution, content of calcium carbonate and humus, density of solid particles, reaction, plastic and liquid limit were determined with Proctor's method (ρds). Also, packing density and natural density were measured. It was found out that the investigated soils may be generally included to excessively compacted and susceptible to compaction to an average and small degree. It was shown that soil may be recognized as excessively compacted when the quotient ρd/ρds exceeds the value of 0.87.

The efficiency of application of virtual cross-sections method and hypotheses MELS in problems of wave signal propagation in elastic waveguides with rough surfaces

2016 ◽  
pp. 3564-3575 ◽  
Author(s):  
Ara Sergey Avetisyan
Keyword(s):  
Half Space ◽  
Cross Sections ◽  
Classical Method ◽  
Signal Propagation ◽  
Elastic Half Space ◽  
Layered Systems ◽  
Surface Layers ◽  
Inhomogeneous Surface ◽  
Wave Signal ◽  
The Impact

The efficiency of virtual cross sections method and MELS (Magneto Elastic Layered Systems) hypotheses application is shown on model problem about distribution of wave field in thin surface layers of waveguide when plane wave signal is propagating in it. The impact of surface non-smoothness on characteristics of propagation of high-frequency horizontally polarized wave signal in isotropic elastic half-space is studied. It is shown that the non-smoothness leads to strong distortion of the wave signal over the waveguide thickness and along wave signal propagation direction as well.  Numerical comparative analysis of change in amplitude and phase characteristics of obtained wave fields against roughness of weakly inhomogeneous surface of homogeneous elastic half-space surface is done by classical method and by proposed approach for different kind of non-smoothness.

Development of Strategies for Glycopeptide Synthesis: An Overview on the Glycosidic Linkage

2020 ◽  
Vol 24 (21) ◽  
pp. 2475-2497
Author(s):  
Andrea Verónica Rodríguez-Mayor ◽  
German Jesid Peralta-Camacho ◽  
Karen Johanna Cárdenas-Martínez ◽  
Javier Eduardo García-Castañeda
Keyword(s):  
Chemical Synthesis ◽  
Solid Phase ◽  
Building Blocks ◽  
Heterogeneous Environments ◽  
Phase Synthesis ◽  
Low Concentrations ◽  
Biological Sources ◽  
Synthetic Routes ◽  
The Impact ◽  
Potential Use

Glycoproteins and glycopeptides are an interesting focus of research, because of their potential use as therapeutic agents, since they are related to carbohydrate-carbohydrate, carbohydrate-protein, and carbohydrate-lipid interactions, which are commonly involved in biological processes. It has been established that natural glycoconjugates could be an important source of templates for the design and development of molecules with therapeutic applications. However, isolating large quantities of glycoconjugates from biological sources with the required purity is extremely complex, because these molecules are found in heterogeneous environments and in very low concentrations. As an alternative to solving this problem, the chemical synthesis of glycoconjugates has been developed. In this context, several methods for the synthesis of glycopeptides in solution and/or solid-phase have been reported. In most of these methods, glycosylated amino acid derivatives are used as building blocks for both solution and solid-phase synthesis. The synthetic viability of glycoconjugates is a critical parameter for allowing their use as drugs to mitigate the impact of microbial resistance and/or cancer. However, the chemical synthesis of glycoconjugates is a challenge, because these molecules possess multiple reaction sites and have a very specific stereochemistry. Therefore, it is necessary to design and implement synthetic routes, which may involve various protection schemes but can be stereoselective, environmentally friendly, and high-yielding. This review focuses on glycopeptide synthesis by recapitulating the progress made over the last 15 years.

Introduction to geomicrobiology

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Fossil Fuels ◽  
Solid Phase ◽  
Direct Reduction ◽  
Iron Oxidation ◽  
Mineral Dissolution ◽  
Precipitation Process ◽  
Soluble Ions ◽  
Chemolithoautotrophic Bacteria ◽  
The Impact

Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.

A solid-phase extraction method that eliminates matrix effects of complex pulp mill effluents for the analysis of lipophilic wood extractives

2020 ◽  
Vol 35 (4) ◽  
pp. 577-588
Author(s):  
Sebastian España Orozco ◽  
Philipp Zeitlinger ◽  
Karin Fackler ◽  
Robert H. Bischof ◽  
Antje Potthast
Keyword(s):  
Solid Phase Extraction ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Pulp Mill ◽  
Phase Extraction ◽  
Wood Extractives ◽  
Wood Extractive ◽  
Pulp Mill Effluents ◽  
The Impact

AbstractThe extraction of lipophilic wood extractives from pulp and paper process waters proves to be a challenging task, due to harsh and alternating process and sample conditions. This study has determined the potential use of polymeric sorbents for solid-phase extraction (SPE) and compared to classical silica-based reversed-phase packed columns, with polymeric hydrophilic-lipophilic balanced (HLB) cartridges being the sorbent with the most potential. Recovery functions were obtained with an internal standard mixture representative for the main lipophilic wood extractive groups, which are fatty acids and alcohols, sterols, sterol esters and triglycerides. The impact of pH, sample volume and sample matrix, expressed as TOC and cations, on the retention behavior of lipophilic extractives during SPE of industrial samples were determined with polymeric HLB sorbent. High variations in the composition of pulp mill matrices led to different optimal extraction conditions. Thus, a new SPE protocol was developed, which bypasses matrix interferences and omits the loss of analytes due to sample preparation. The method is applicable to different pulp mill effluents with large discrepancies in pH and sample matrices, resulting in recoveries >90 % with RSD <5 % for all lipophilic wood extractives.

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