Compression Index Research Articles

Strength and consolidation index parameters of stabilise clay soil using scrap rubber tyre

Scrap rubber tyres are one of the synthetic fibre materials that can be used as a soil stabilizer. This study looks into the effects of scrap rubber tyres as a soil stabiliser on clay soil. Soil samples were collected in Kota Kinabalu, and the scrap rubber tyre was passed through a 2 mm passing sieve. Three experimental tests were carried out: compaction, consolidation, and an unconfined compression test (UCT). During the compaction test, the maximum dry density (MDD) and optimum moisture content (OMC) parameters were determined using the proctor standard penetration test. The shear strength of all soil samples was determined using UCT. The consolidation test also looks at the compressibility index and swelling index. Four soil sample configurations were prepared, one as a control sample and three with different soils mixed with varying percentages of scrap rubber tires: 1.5%, 2%, and 5%. This study investigates the degree of compaction, shear strength, settlement behaviour (compressibility), and swelling behaviour of scrap rubber tyres as a soil stabiliser. According to the findings, the optimal amount of scrap rubber tyres as a stabiliser that could improve the properties of clayey soil is 2%.

Deep Learning-Based Soft Iterative-Detection of Channel-Coded Compressed Sensing-Aided Multi-Dimensional Index Modulation

The concept of Index Modulation (IM) has been actively researched as a benefit of its flexible trade-off between performance, achievable rate, energy efficiency, hardware cost and complexity. In order to fully exploit its the degrees of freedom, the concept of Multi-dimensional IM (MIM) has been developed in literature, where Compressed Sensing (CS) is often utilized to exploit the sparsity of the multi-dimensional transmitted signals. However, this flexibility and performance gains are attained at the cost of a substantially increased detection complexity. In this paper, we propose Deep Learning (DL) based detection for CS-aided MIM (CS-MIM), where both Hard-Decision (HD) as well as Soft-Decision (SD) detection combined with iterative decoding are conceived. More explicitly, firstly, we propose learning aided hard and soft detection for CS-MIM. Secondly, two novel neural network aided methods are proposed for Iterative Soft Detection (ISD), where iterations are carried out between the CS-MIM detector and a channel decoder. In contrast to the conventional detection of CS-MIM system, which critically relies on the knowledge of Channel State Information (CSI) at the receiver, the proposed learning-aided methods are capable of eliminating the overhead and complexity of Channel Estimation (CE), which results in an improved transmission rate. Explicitly, we develop an advanced DL architecture for blind-detection-aided MIM for the first time in the open literature, where the HD and SD CS algorithms are implemented by learning without the need for CE. Our simulation results demonstrate that the proposed learning techniques conceived for SD CS-MIM combined with iterative detection are capable of achieving near-capacity performance at a reduced complexity compared to the conventional model-based SD relying on CSI acquisition.

Experimental Investigation on the Influence of Temperature on Coal and Gas Outbursts

With the increasing mining depth, the dynamic disaster of coal and gas outbursts in coal mines has become increasingly prominent, and the bursting liability of coal and rock mass in deep coal seam mining is a necessary condition for the occurrence of rock burst and an important index to measure the failure of coal and rock mass. Thermal damage leads to rock instability and failure, which seriously influences the safe and efficient operation of coal mines. To investigate the effect of thermal damage on the bursting liability of deep coals, the burst tendency index of standard coal was measured after subjecting it to thermal damage at different temperatures. The effects of different thermal damage temperatures on the uniaxial compressive strength index, dynamic failure duration, stiffness ratio index, effective impact energy index, residual energy index change rate, and impact energy velocity of the coal and the influence of the post-peak failure mode of the coal were evaluated. The results revealed that the uniaxial compressive strength of the coal generally decreased with increasing thermal damage temperature. At temperatures above 200 °C, the strength significantly decreased. The comprehensive impact property index indicated that, with increasing thermal impact temperature, the burst tendency first increased up to the peak value at 200 °C and then gradually decreased. With the increase in the thermal damage temperature, the burst tendency decreased and disappeared in the temperature range of 250–300 °C, and the failure mode of the coal changed from brittle failure to brittle plastic failure, and finally ductile failure. The influence of thermal damage on coal bursting liability is studied, which provides a theoretical basis for preventing and controlling coal impact ground pressure hazards.

Formulation and evaluation of colon targeted matrix tablet of ibuprofen

The present work involves the formulation of colon targeted matrix tablet of Ibuprofen by using direct compression method. Literatures regarding, Ibuprofen tablet dosage form preparation, excipients selection, manufacturing method etc., has been collected and reviewed. In this work, selection of excipients was done based on a literature review. Excipients include Eudragit S100, Ethyl cellulose, Lactose, Talc, Magnesium stearate. Quantities of the excipients were selected performing FT-IR method which is an HIS of Fourrts India Laboratory. Preformulation studies have also been performed to study the nature of API and compatibility of API with excipients by physical observation and FT-IR studies. The result showed that API was compatible with all the excipients selected. The tablets were formulated by direct compression method using the selected excipient quantities. The formulated tablets were tested for both pre-compression parameters and post compression parameters as per requirements of standards. Pre-compression parameters such asbulk density, tapped density, compressibility index, Hausner’s ratio and compressibility index. The results obtained indicate that it has good flow property for direct compression. The formulated Ibuprofen matrix tablets were coated with enteric polymer Eudragit FS30D by pan coating method. The prepared tablets were evaluated for weight variation, hardness, thickness, friability, drug content, and disintegration time and in-vitro dissolution studies. All these parameters were found to be within the standard limits. Comparative studies of coated Ibuprofen tablets and uncoated Ibuprofen tablets are evaluated for the hardness, thickness, in-vitro dissolution studies and disintegration time. Out of six formulations, the formulation F6 showed 98.51% drug release at 24 hrs. Since it provide greater protection to the core under acidic condition while at the same time show the fastest drug release under intestinal pH. So the formulation F6 was considered as the confirmatory trial and it was subjected for stability studies up to three months of accelerated stability 400C ± 2C0, 75 %± 5 % RH and found to be within limits.

Study on the compression behavior and strain rate effect of Zhuhai soft clay

As a marine deposit, Zhuhai soft clay generally exhibits poor mechanical and engineering properties. In order to investigate its compression behavior, a series of incremental loading (IL) tests and constant rate of strain (CRS) tests were conducted on both intact and reconstituted samples. The compression index (Cc ), coefficient of secondary compression (Ca ), and the ratio Ca /Cc of Zhuhai clay were determined using the end of primary (EOP) concept. In IL tests, the ratio Ca /Cc was found to be non-constant, but varied with time and vertical stress. Furthermore, CRS tests revealed an unexpected strain rate effect that deviated from the classical stress-strain-strain rate relationships. Specifically, the compression curves obtained at different strain rates were not parallel, but gradually approached each other at high stress levels. Regression analysis results suggested a positive correlation between the strain rate and the compression index, indicating that higher strain rates resulted in a greater compression index. To acquire a comprehensive understanding of this unusual phenomenon, a concise review of several relevant works was conducted. It is postulated that the observed discrepancy between Zhuhai clay and the classical isotache concept may be attributed to the development of microstructure and the evolution of Ca /Cc during the loading.

Integrating wheat straw and silica fume as a balanced mechanical ameliorator for expansive soil: a novel agri-industrial waste solution.

Resource utilization of agricultural and industrial wastes with minimal screening is highly desirable in the context of sustainable development and environmental protection. In this regard, the current study proposes a novel solution of integrating milled wheat straw (WS) with minimal screening and silica fume (SF) in the form of composite binary admixture (CBA) for the stabilization of highly expansive soils. The optimum amount of WS and SF to produce CBA was determined based on a series of Atterberg's limit tests. The mechanical performance of CBA-treated soil was assessed based on the unconfined compression, direct shear, and flexural tests which showed that unconfined compressive strength (qu), cohesion (c), and flexural strength (f) were increased by 94.3%, 65.7%, and 90.7%, respectively, with an addition of 16% of CBA and 28 days of curing. Furthermore, the CBA-treated soil underwent only a 26% reduction in deformability index (ID) with an addition of 24% CBA. Furthermore, volumetric change response was assessed based on ID consolidation and swelling tests which showed that compression index (Cc), recompression index (Cr), swell potential, free swell index (FSI), and swell pressure were reduced by 72.5%, 47.7%, 59%, 35.8%, and 65%, respectively, with an addition of 16% CBA in the soil and 28 days of curing. In addition, wetting-drying (W-D) cycle tests demonstrated that CBA-treated soil was less vulnerable to W-D seasons as compared to untreated soil. Mineralogical and microstructural tests revealed that the balanced Ca:Si and Ca:Al environment created by CBA within the soil matrix produces cementing compounds, i.e., CSH and CAH, imparts strong bonds, and causes aggregation improving the mechanical response of expansive soil.

Formulation and Evaluation of Anti-Diabetic Tablet from Insulin Plant (Costus Igneus)

In this research article we prepare tablet formulation of Costus igneus plant i.e., Insulin plant by its ethanolic leaves extract and mixing with suitable excipients. Extract was prepared by collecting Costus igneus plant leaves and go for shade drying for 4-7 days, after drying its crushed by mill to form powder and taken for extraction. After extraction we prepare powder for taking different chemical qualitative test and laboratory flow properties such as; (Angle of repose, Loose bulk density, Tapped bulk density , Compressibility index) and after checking flow properties and then punch tablet by direct compression method we take two forms of tablet formula changes in main API one is extract and other is only powder and go for evaluation study such as; ( Color ,Weight variation Test ,Hardness, Friability, Disintegration Time, Thickness)

EESD special issue: AI and data‐driven methods in earthquake engineering – (Part 1)

EESD special issue: AI and data‐driven methods in earthquake engineering – (Part 1)

Relevance of finite element analysis to simulate oedometer test for estimating the compressibility of soil

One-dimensional consolidation behavior of soil is usually evaluated by the conventional laboratory oedometer test, which is a time-consuming test process. Several researchers have focused on to correlate compressibility with various index properties in terms of single and multiple regressions. However, those correlations are not generalized and have some limitations. The main objective of this paper has been to simulate the compressibility behavior of soil with laboratory experimental data using three-dimensional (3D) finite-element (FE) model in PLAXIS-3D. This analysis is performed assuming the material behavior as linear elastic perfectly-plastic Mohr-Coulomb (MC) model. Furthermore, FE simulations were compared with the laboratory test results as well as existing empirical equations to verify the outputs of the numerical analyses. It has been noticed that, the empirical equations suggested in previous studies are found to have uncertainties (−80 to +374% deviation) in estimating compression index and simulation results by the proposed model are reliable (+1.92 to +12.03% deviation) to the laboratory test values.

Optimasi Formulasi Tablet Lepas Lambat Ekstrak Seledri (Apium graveolens L.) Menggunakan Polimer Xanthan Gum dan Lubrikan Magnesium Stearat dengan Metode Simplex Lattice Design (SLD)

Antihypertensive drugs undergo first-pass metabolism and therefore have low oral bioavailability. It causes an increase in the frequency of drug use and concentration fluctuations that affect patient comfort. The sustained release tablet formulation was chosen because it can deliver the active substance with good bioavailability. An active antihypertensive substance that can be used is celery extract because it contains flavonoids, so a sustained release tablet formulation was made using xanthan gum and magnesium stearate to produce a constant and controlled release rate. This study aims to knowing the results of celery extract sustained release tablet evaluation using different concentrations of xanthan gum and magnesium stearate, and also obtains the optimal formulation. The manufacture of tablets uses the direct compression method. Powder evaluations include flow property through a funnel, angle of repose, compressibility index, and moisture content. Tablet evaluations include organoleptic, weight uniformity, size uniformity, hardness, friability, disintegration time, and dissolution tests. The evaluation results data were analyzed using Simplex Lattice Design. The powder evaluation result of all formulations meets the requirements of flow property through a funnel, angle of repose, compressibility index, and moisture content. Physical evaluation of the tablets shows all formulations meet the requirement of weight uniformity, hardness, and friability tests. On the size uniformity test, all formulations do not meet the requirement. The disintegration time test results show that F1 does not meet the requirement. Meanwhile, the dissolution test results show that F4 is the best formula because it shows constant and controlled release rate. Based on analyzed using Simplex Lattice Design, the F4 is the most optimal formula with xanthan gum 52 mg and magnesium stearate 3 mg.

Development of cryo‐desiccated whey and soy protein conglomerates; effect of maltodextrin on their functionality and digestibility

AbstractThis study aims at enhancing the thermal stability, functional properties, and digestibility of the protein isolates by addition of maltodextrin. Higher total soluble solid content, less cohesiveness, and high hygroscopicity of maltodextrin allow the protein isolates to show better thermal and functional stability along with improved digestibility. The functionality of powders depends on their particle size, the structure of particles, shape, flowability, and wettability, etc. The effect of maltodextrin (5%, 10%, 15%, and 20%) on the functional properties of WPI, SPI, and the mixture of these proteins (1:1 ratio) was evaluated in this study. The samples were prepared in distilled water (10 w/v % solution of SPI and WPI), cryo‐desiccated (freeze‐dried), and then further dried using a fluidized bed drier (at 80, 90, 100°C) to improve the functional properties. The addition of 15% maltodextrin was obtained as an optimum condition as it provides good functional properties (flowability such as cohesiveness, compressibility index, angle of repose, wettability, solubility, color, and water activity) with maximum thermal stability (113 ± 2°C for WPI, 115 ± 0.5°C for SPI and 118 ± 0.1°C for mixture) studied using differential scanning calorimetry. The powders were further characterized using FTIR, SEM, and SDS‐PAGE to evaluate the effect of in‐vitro digestibility on the protein conglomerates. The in vitro digestibility of the conglomerates containing WPI, SPI, and the mix was 91.24% ± 2.5, 56.48% ± 3.9, and 80.71% ± 3.1, respectively, and show good stability in the gastric phase (pH < 3), which depicts the resistance of conglomerates due to maltodextrin. These protein conglomerates can be ingested orally to gain the benefits of plant and animal proteins simultaneously and can also be incorporated in functional beverages and food items to improve the nutritional value.Practical applicationsThe functional properties of animal protein (WPI) and plant protein (SPI) were improved by the addition of maltodextrin. The maltodextrin improves the gastric digestibility and pH stability of the protein conglomerates. These animal and plant‐based protein conglomerates can be utilized in diets or functional foods as a good source of protein constituents. Higher protein content with good solubility can be attractive to food manufacturers in preparing semi‐solid and liquid novel food systems. Alternatively, these powders can be consumed as dietary supplement to increase the protein uptake and for better digestibility.

Changes in geotechnical properties of soil contaminated by methyl tertiary butyl ether (MTBE)

As an extensively used gasoline additive, methyl tertiary butyl ether (MTBE) can leak into the subsurface, and this not only damages the ecological environment but also affects the geotechnical characteristics of the soil. In this study, the geotechnical properties of MTBE-contaminated soil, such as the basic physical properties of strength, compressibility, hydraulic conductivity, leachability, electrical resistivity and microstructural characteristics, are comprehensively investigated. The results show that the Atterberg limits consistently decrease with increasing MTBE content in the soil. As the MTBE content increases from 0 to 10%, the specific surface area of the soil decreases by 28%, the sand content increases by 22%, and the clay and silt contents decrease by 3 and 18%, respectively. The soil compression index, hydraulic conductivity, leached MTBE concentration and electrical resistivity increase, while the unconfined compressive strength (UCS) decreases, with increasing MTBE content. Microstructural analysis shows that increasing the MTBE content results in mineralogical alterations that decrease the illite and kaolinite content of the soil. The aggregation and flocculated structures can be detected by an increase in the number and size of inter-aggregate pores. In addition, the electrical resistivity of the contaminated soil is used to assess the geotechnical properties of the MTBE-contaminated soil based on well-established empirical relations.

Robust models to predict the secondary compression index of fine-grained soils using multi objective evolutionary polynomial regression analysis

Robust models to predict the secondary compression index of fine-grained soils using multi objective evolutionary polynomial regression analysis

Influence of iron ore concentrate quality on metallurgical properties of pellet

One of the important factors for improving the technical and economic performance of blast furnaces is the iron content in the iron ore part of the charge. At the same time, there is evidence that when using iron ore concentrate with an iron content of more than 66‒67% for the production of pellets, their strength decreases, and adjustments to the heating modes are required. In recent years, Russian mining enterprises have been implementing technological measures to increase the mass fraction of iron in the concentrate to 68‒70%. The results of a study of the influence of concentrate quality indicators (mass fraction of iron, specific surface value) on the pelletizing technology and metallur-gical properties of pellets are presented. Concentrates with a mass fraction of iron of 66.6, 68.0, 69.2% and a specific surface of 1576, 1999, 2015 cm2/g, respectively, were used as an object of study. It was found that increasing the iron content and specific surface area in the concentrate leads to an improvement in the raw pelletizing technology ‒ plasticity and the proportion of pellets with a size of 5‒16 mm increase. Roasting of laboratory pellets in baskets on a roasting machine showed a multidirectional change in the metallurgical properties of the pellets. The compressive strength index decreased, the hot strength changed little, the softening-melting temperature range (SMTR) decreased from 308 to 200‒290 °C. Mineralogical studies have established that the decrease in these indicators (strength and SMTR) was influenced by a decrease in the amount of silicate binder and the uneven distribution.

Soil Compaction Mechanism and Improvement in Farmland

To improve the quality of sloping soil in farmlands, exploring the mechanism of farmland soil consolidation is vital. This study investigated the improvement of soil pH, exchangeable acid, crop economic characteristics, and the soil compression index under different soil amendments using field experiments and laboratory-simulated cultures. The results show that (1) increasing the pre-consolidation pressure of the soil and reducing the soil compression index and bulk density significantly reduces the risk of soil compaction; (2) soil compression performance improved after the addition of organic and bio-carbon fertilizers and other modifiers to the compacted soil. The comprehensive physical index compression curve (S) value was higher than 0.05; (3) the addition (biomass carbon + chitosan 32 t/hm2) had the best improvement effect, which significantly increased soil pH, reduced soil exchange acid, and prevented the dissolution of soil H+ and Al3+. Dissolution also reduced the risk of soil compaction stress in rice and significantly increased root thickening and yield. Based on the stagnation mechanism of farmland soil and the improvement principle of physical properties, a comprehensive improvement technology for farmland soil compaction is proposed.

Effect of fluorite addition on the reactivity of a calcined treated spent pot lining in cementitious materials

Treating SPL by the low caustic leaching and liming process generates an inert nonhazardous residue called LCLL Ash and a fluorite byproduct Calcined LCLL Ash that is ground into a fine powder demonstrates pozzolanic behavior in cement. The effect of the calcination temperature and fluorite byproduct addition on the reactivity of LCLL Ash was studied by the compressive strength activity index, Frattini test and Rilem R3 tests followed by XRD analysis. At 800°C, the formation of nepheline causes alkali uptake, the LCLL Ash showed a slightly lower reactivity with 10% fluorite addition. At 1000°C, calcined LCLL Ash/CF showed a better amorphization of phases and increasing reactivity due to reactions between fluorite and sodium oxide. Unlike LCLL Ash, no delay in hydration or hydro reactivity was observed with calcined LCLL Ash/CF.

The Combined Effect of Calcium Chloride and Cement on Expansive Soil Materials

In this study, the chemical stabilization of moderately to highly plastic expansive soil using calcium chloride with added cement is introduced as an effective alternative to the conventional approaches using a single additive such as lime, cement, or a by-product of industrial processes. Using only calcium chloride may lead to its leaching or dissolution over time, leaving a collapsing skeleton with weak bonds. The chemical effect produced by additives is dependent on the constituents of the stabilized soil and the curing period considered. Herein, calcium chloride concentrations of 2%, 4%, and 8% with the addition of 2% cement by dry weight of the soil were considered. The main objective of this study is to investigate the addition of a low amount of cement as a binder to improve the strength and durability of a chemically treated expansive soil. The engineering properties were investigated at 3 curing times: 3 days, 7 days, and 28 days. A laboratory investigation was carried out to investigate the effect of the addition of calcium chloride with cement on the swell potential, swell pressure, compression index, suction, and unconfined compressive strength. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) testing was conducted. The X-ray diffraction patterns were recorded to observe the mineralogy of the material. The results confirmed that calcium chloride with cement is very effective for stabilizing the expansive soil. A reduction in the swell potential by 8% and 25% and a reduction in swelling pressure by 28% and 37.4% were observed for 4% and 8% calcium chloride with cement addition. The compression index decreased with the increase in the calcium chloride content.

An Experimental Study on the Effect of Plastic Waste Powder on the Strength Parameters of Tuff and Bentonite Soils Treated with Cement

This experimental study investigated the effect of plastic waste powder on the strength and swelling behavior of tuff and bentonite soils treated by cement since the plastic powder is highly compressible and does not absorb much water. This study aimed to improve the tuff and bentonite soils used in construction by adding plastic waste powder in various ratios (5, 10, 20, and 25%) and a low cement content (2.5%). Atterberg limit, swelling consolidation, and loading-unloading tests were performed to determine the optimal composition of the mixture. The results demonstrated that as the plastic powder content increases, the liquid limits, swelling pressure, swelling potentials, and duration to swelling peak decrease. This reduction is particularly notable for the soil with the highest swelling potential. Compression and recompression indices increase significantly with the content of plastic powder due to its high compressibility. The findings suggest that plastic powder with low cement can be utilized as a soil modification reinforcement material, but with a content that shouldn't significantly alter the compressibility of the mixture.

Global void ratio of municipal solid waste for compression indices estimation.

Compressibility is one of the important engineering properties of municipal solid waste (MSW) affecting the stability and functionality of a landfill. Although the correlations between MSW properties and compression parameters have been established, they either have low accuracy and small datasets or are only limited to a few specific landfills in a region. In this study, a new method using the initial global void ratio (e0*) of MSW to estimate the compression indices is developed based on a comprehensive MSW dataset. The dataset consists of 124 sets (91 laboratory and 33 field) of MSW compression results obtained from 44 studies in 13 countries with different income levels and climate conditions. We categorized MSW as a ternary mixture with biodegradable (B), reinforcing (R), and inert (I) fractions, and suggested average specific gravity values (Gs,B=1.20, Gs,R=1.07, and Gs,I=2.64), respectively. The e0* values were calculated using the initial dry unit weight (γd,0) and ternary composition of MSW. The correlations between the e0* and the immediate compression index, secondary compression index induced by mechanical creep, and secondary compression index induced by bio-compression of MSW were evidently established. The results are applicable to the MSW with B=0-79.2%, R=0-54.0%, I=2.8-100.0%, and γd,0=2.0-14.2 kN/m3. A simple flowchart was established to estimate the compression indices and strains of MSW disposed on in landfills and dumpsites in countries with different income levels.

Associations between blood antioxidant levels and femoral neck strength

BackgroundStudies have confirmed that antioxidants contribute to a lower risk of osteoporosis, which is an independent factor for femoral neck fracture (FNF). However, the associations between blood antioxidant levels and femoral neck strength remain unclear.ObjectiveOur aim was to test the hypothesis that levels of blood antioxidants are positively associated with composite indices of bone strength in femoral neck, which integrate the bending strength index (BSI), compressive strength index (CSI), and impact strength index (ISI), in a population of middle-aged and elderly individuals.MethodsThis cross-sectional study utilized data from the Midlife in the United States (MIDUS) study. Blood levels of antioxidants were measured and analyzed.ResultsIn total, data from 878 participants were analyzed. Results of Spearman correlation analyses indicated that blood levels of 6 antioxidants (total lutein, zeaxanthin, alpha-carotene, 13-cis-beta-carotene, trans-beta-carotene and total lycopene) were positively associated with CSI, BSI, or ISI in middle-aged and elderly individuals. Conversely, blood gamma-tocopherol and alpha-tocopherol levels were negatively associated with CSI, BSI, or ISI scores. Furthermore, linear regression analyses suggested that only blood zeaxanthin levels remained positively associated with CSI (odds ratio, OR 1.27; 95% CI: 0.03, 2.50; p = 0.045), BSI (OR, 0.54; 95% CI: 0.03–1.06; p = 0.037), and ISI (OR, 0.06; 95% CI: 0.00, 0.13; p = 0.045) scores in the study population after adjusting for age and sex.ConclusionsOur results indicated that elevated blood zeaxanthin levels were significantly and positively associated with femoral neck strength (CSI, BSI, or ISI) in a population of middle-aged and elderly individuals. These findings suggest that zeaxanthin supplementation may reduce FNF risk independently.