Search

This paper presents the study on compaction characteristics of pond ash. Three different types of pond ash have been used in this study. The effects of different compaction controlling parameters, viz. compaction energy, moisture content, layer thickness, mold area, tank size, and specific gravity on dry density of pond ash are highlighted herein. The maximum dry density and optimum moisture content of pond ash vary within the range of 8.40-12.25 kN/[m.sup.3] and 29-46%, respectively. In the present investigation, the degree of saturation at optimum moisture content of pond ash has been found to vary within the range of 63-89%. An empirical model has been developed to estimate dry density of pond ash, using multiple regression analyses, in terms of compaction energy, moisture content, and specific gravity. Linear empirical models have also been developed to estimate maximum dry density and optimum moisture content in the field at any compaction energy. These empirical models may be helpful for the practicing engineers in the field for planning the field compaction control and for preliminary estimation of maximum dry density and optimum moisture content of pond ash. DOI: 10.1061/(ASCE)0899-1561(2007)19:4(349) CE Database subject headings: Fly ash; Density; Moisture content; Regression analysis; Soil compaction.

In the present paper, a series of compaction tests have been performed to investigate the effect of fly ash content on compaction characteristics of fly ash clay mixture. Three types of fly ash and three types of clay have been used in this investigation. From the test results, it is observed that with the increase in fly ash content (0 to 25%) in the fly ash clay mixture, the value of maximum dry density decreases irrespective of type of soil, type of fly ash and type of compaction method. Fly ash content also influences significantly the optimum moisture content of fly ash clay mixture. Based on the present experimental data, a number of linear regression models have been developed to estimate the values of optimum moisture content and maximum dry density of fly ash clay mixture. [ABSTRACT FROM AUTHOR]

In the present paper, log linear regression models have been developed to estimate the maximum dry unit weight and optimum moisture content of fine grained soil. The parameters such as compaction energy, specific gravity, liquid limit, and grain size (grain size, corresponding to 50% finer particles) are showing the significant contribution for both the models for predicting the maximum dry unit weight as well as optimum moisture content of fine grained soil. All possible regression techniques have been performed for predicting the best models. The above models are useful within the range of 318.10 - to 10832.10 kJ/m³, 2.60 to 2.80, 30.81 - to 213.27 %, and 0.0008 - to 0.019 mm for compaction energy, specific gravity, liquid limit, and grain size (Grain size, corresponding to 50% finer particles) respectively. [ABSTRACT FROM AUTHOR]

This paper presents the ultimate bearing capacity of square footing on pond ash reinforced with a single layer of geotextile reinforcement. The effect of different vital bearing-capacity parameters on the ultimate bearing capacity (qru) of square footing on reinforced pond ash has been studied. Parameters considered include depth of the reinforcement layer below the footing (u) and friction ratio (f = ψ/ϕd)-that is, the ratio of the pond ash reinforcement interface friction angle (ψ) to the direct shear friction angle of pond ash (ϕd). The value of u/B (B being the width of footing) corresponding to the maximum ultimate bearing capacity is considered as optimum u/B in the current study. In the present investigation the value of optimum u/B ratio was found to increase with increase in friction ratio (f ). With increase in friction ratio (f ), bearing capacity ratio (BCRu (qru=qu) where qu is the ultimate bearing capacity of square footing, of the same size as that for qru, on unreinforced pond ash) increases. In the present investigation BCRu increases from 1.1180 to 1.4158 with a corresponding increase in friction ratio (f ) of 0.7073 to 0.9230. [ABSTRACT FROM AUTHOR]

Abstract: At present an enormous amount of pond ash is being produced by thermal power plants throughout the world. Storage of pond ash requires vast land area and disposal of ash becomes problematic and also it creates environmental hazards. To mitigate these problems, pond ash has been used in the low-lying areas as structural fills for developing residential and industrial sites. To enhance the bearing capacity of pond ash, it may be reinforced with jute-geotextile, a textile made from jute (natural fibre) for the purpose. In the present study an attempt has been made to study the bearing capacity of square footing on pond ash reinforced with jute-geotextile. The effects of different parameters like number of layers (N) of reinforcement, the depth of the upper most layer of reinforcement from the base of the footing (u), friction ratio (f), i.e. the ratio of the pond ash jute-geotextile interface friction angle (ψ) to the direct shear friction angle of pond ash (φ d) and jute-geotextile sheet length (L s) on bearing capacity of square footing (q rs) at any settlement resting on pond ash reinforced with jute-geotextile are discussed. A non-linear power model has been developed to estimate q rs based on 1399 experimental data. [Copyright &y& Elsevier]

Bioprinting a resilient yet optically transparent corneal tissue substitute remains a challenge. In this study we introduce an innovative methodology aimed at bolstering the mechanical and optical attributes of silk fibroin (SF) hydrogels, pivotal for the progression of cornea tissue engineering. We devised a unique eosin Y-based photoinitiator system to instigate di-tyrosine linkages within highly concentrated pristine SF solutions under green light exposure. This pioneering technique resulted in SF hydrogels fortified by dityrosine covalent bonds, preserving exceptional transparency and soft elastomeric qualities devoid of spontaneous transitions to stiff, opaque beta-sheet conformations. Furthermore, we synergistically combined SF with decellularized cornea matrix (DCM) hydrogel, leveraging photo-polymerization under green light followed by thermal gelation to establish resilient and stable gel formation. The ensuing dual crosslinked hybrid hydrogels exhibited superior mechanical and thermal resilience in comparison to dual crosslinked DCM hydrogels. The inclusion of SF in DCM further augmented the hydrogel's elasticity and shear recovery, positioning it as an optimal bioink for cornea bioprinting endeavors. During the extrusion printing process, photocrosslinking of the bioink superficially fortified SF and DCM polymer chains via di-tyrosine linkages, furnishing initial stability and mechanical fortitude. Subsequent post-printing thermal gelation further reinforced collagen chains through self-assembly. Notably, the bioprinted cornea constructs, housing human limbal mesenchymal stem cells, manifested transparency, structural integrity, and optimal functionality, underscored by the expression of keratocyte proteoglycans. In summation, our engineered 3D constructs exhibit promising potential for in vivo applications in cornea tissue engineering, marking a significant stride forward in the field's advancement., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

In the realm of tissue engineering, replicating the intricate alignment of cells and the extracellular matrix (ECM) found in native tissue has long been a challenge. Most recent studies have relied on complex multi-step processes to approximate native tissue alignment. To address this challenge, we introduce a novel, single-step method for constructing highly aligned fibrous structures within multi-modular three-dimensional conglomerates. Our approach harnesses the synergistic potential of extrusion-based bioprinting and the fibrillogenesis kinetics of collagen-rich decellularized ECM. We have identified three key parameters governing ECM microfiber alignment during extrusion-based bioprinting: applied shear stress, stretching or extensional force, and post-print deformation. By carefully manipulating these parameters, we have successfully created highly aligned fibrous structures within multi-modular three-dimensional conglomerates. Our technique offers an efficient solution and has been validated by computational modeling. Comprehensive analyses confirm the efficacy across various scenarios, including encapsulated, top-seeded, and migratory cells. Notably, we have demonstrated the versatility and effectiveness of our approach by bioprinting highly aligned cardiac tissue patches, which show further maturation evidenced by the expression of Troponin-T and Myo-D differentiation factor needed for contractility and myotube formation, respectively. In summary, our streamlined approach offers a robust solution for creating anisotropic tissue analogues with precise ECM organization., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Recent advancements in 3D cancer modeling have significantly enhanced our ability to delve into the intricacies of carcinogenesis. Despite the pharmaceutical industry's substantial investment of both capital and time in the drug screening and development pipeline, a concerning trend persists: drug candidates screened on conventional cancer models exhibit a dismal success rate in clinical trials. One pivotal factor contributing to this discrepancy is the absence of drug testing on pathophysiologically biomimetic 3D cancer models during pre-clinical stages. Unfortunately, current manual methods of 3D cancer modeling, such as spheroids and organoids, suffer from limitations in reproducibility and scalability. In our study, we have meticulously developed 3D bioprinted breast cancer model utilizing decellularized adipose tissue-based hydrogel obtained via a detergent-free decellularization method. Our innovative printing techniques allows for rapid, high-throughput fabrication of 3D cancer models in a 96-well plate format, demonstrating unmatched scalability and reproducibility. Moreover, we have conducted extensive validation, showcasing the efficacy of our platform through drug screening assays involving two potent anti-cancer drugs, 5-Fluorouracil and PRIMA-1 Met . Notably, our platform facilitates effortless imaging and gene expression analysis, streamlining the evaluation process. In a bid to enhance the relevance of our cancer model, we have introduced a heterogeneous cell population into the DAT-based bioink. Through meticulous optimization and characterization, we have successfully developed a biomimetic immunocompetent breast cancer model, complete with microenvironmental cues and diverse cell populations. This breakthrough paves the way for rapid multiplex drug screening and the development of personalized cancer models, marking a paradigm shift in cancer research and pharmaceutical development., (© 2024 IOP Publishing Ltd.)