Intentional creation and propagation of fractures driven by fluid under high pressure have several applications in oil and gas exploration, geological mining, disposal of toxic waste, flow of molten ...magma within crevices/fissures, etc. Due to the need to design hydraulic fractures, especially in the oil and gas industry, and the limitation of their full scale/field testing, the use of laboratory experiments and/or numerical simulations remain viable alternatives. While several computational methods for this class of problems exist in the literature, their reliability and robustness hinge on their ability to replicate experimental results with acceptable confidence. This paper presents the application of a coupled multiphysics 3-D generalized finite element method (GFEM) for the simulation of hydraulic fracture experiments based on a regularized Irwin criterion and adaptive mesh refinement. Built with an automatic time step search, the algorithm computes the time step size that ensures the satisfaction of the propagation criterion. Modes I, II, and III stress intensity factors are computed using the displacement correlation method, while the fracture propagation direction is determined using the Schöllmann’s criterion, which is a generalization of the maximum tangential stress criterion for 3-D stress state. The GFEM is validated against a hydraulic fracture experiment on PMMA specimen, on one hand, and against four different cases of experimental fractures within concrete (a granite-like) material which serves as the pioneer application of the algorithm to verify hydraulic fracture simulation in non-PMMA materials. The influence of the initial shear stresses along the fracture plane (assuming unnotched condition) on the resulting propagation paths in the latter benchmarked problem is also assessed and found to have good agreement with experimental observations.
•GFEM simulation of hydraulic fracture experiments in PMMA and concrete materials.•Pioneer application of the algorithm to hydraulic fracture in non-PMMA materials.•Influence of initial notch shear stresses on fracture propagation paths is verified.•Excellent agreement with experimental fracture footprints, opening history, and speed is shown.•Injection pressure history comparable with the experiment after steady-state condition.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Making physical sense of the shear behavior of reinforced concrete (RC) elements remains an open challenge and an ongoing investigation that often leads to upgrades of design codes/provisions. The ...physically sound Critical Shear Crack Theory (CSCT) which forms the basis for shear design in some popular design codes has been mainly successful in steel-RC members, but not adapted to concrete members reinforced with fiber reinforced polymer (FRP) bars, given that the shear behavior of the latter is significantly less comprehended compared to that of the former. The present study, therefore, aims to develop a model for the shear strength of FRP-RC elements by refining the CSCT parameters. An extensive experimental database is compiled with a total of 420 shear-controlled slender FRP-RC beams without stirrups from 56 investigations – the largest database of this structural material type ever compiled. In addition to being physically sound, the strength predictions by the developed model are found to be accurate, compared to existing design methods. It is adaptable for predicting the shear strength of slender FRP-RC as well as being valid for steel-RC elements. The new model's size effect consistency is verified, and it proves to be more robust than that of the traditional CSCT. In the case of FRP-RC members, the latter wrongly signifies size effect behavior that mostly obeys the linear elastic fracture mechanics (which is believed to be too strong for concrete) while the former predicts a more physically logical behavior similar to that of the nonlinear fracture mechanics.
•A model for shear capacity of FRP-reinforced concrete members is presented.•Framework premised on the Critical Shear Crack Theory (CSCT) based on physically sound mechanics and less empiricism.•Size effect consistency mimics that of the nonlinear fracture mechanics.•Analysis based on the most updated database of shear controlled FRC-RC members without stirrups.•The model outperforms the traditional CSCT for FRP-RC members and is valid for steel-RC elements as well.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An approach, the radial basis function (RBF) collocation method, is used to obtain numerical solution of both elastic and elastoplastic problem of a pressurized functionally graded tube. RBF is a ...meshless technique that does not require discretization into elements as is usually done in the finite element method. The implementation of the scheme is achieved with the aid of MATHEMATICA commercial software. The use of the RBF eliminates the need for the hypergeometric function, which has the disadvantage of converging slowly in addition to its complexity. Numerical example for utilizing this scheme is used to show its efficiency and reliability. Excellent agreement with the available literature analytical result is achieved.
•Direct dual Z-scheme TiO-WO3-CeO2 heterostructured nanocomposite successfully synthesized by co-precipitation route.•The nanocomposite TiO-WO3-CeO2 showed boosted photocatalytic activity towards ...different pollutants.•Systematic investigations confirmed the superior charge separation by direct dual Z-scheme.•Enhanced antibacterial activity of nanocomposite against various pathogenic bacterial strain.•The higher super-capacitive behaviour of nanocomposite.
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Direct dual Z-scheme heterostructured nanocomposite TiO2-WO3-CeO2 (NC) and pristine metal oxides nanostructures (NSs) were fabricated using a facile co-precipitation route. XRD, FTIR, and Raman data have confirmed the formation of NSs and NC. FESEM images showed quasi-mesoporous morphology of as-grown nanocomposite. EDX analysis confirmed the existence of titanium (Ti), cerium (Ce), and tungsten (W) in grown NC. The energy bandgap of NC was narrow 2.45 eV as compared to NSs. The higher electrical conductivity and lower recombination rate of NC were observed in IV and PL analysis. The photodegradation efficiency of NC was recorded 99.8% after 60 min under sunlight radiation against methylene blue (MB), which was significantly higher than NSs. NC catalyst has shown excellent photodegradation against other organic pollutants and has superior recyclability up to 7th cycle toward MB dye with a ~ 6% deficit in photodegradation efficiency. The antimicrobial activity results indicated the higher inhibition ability of NC against E. coli, K. pneumoniae, S. aureus, P. Vulgaris, and P. aeruginosa with maximum inhibition zone diameter 25, 29, 26, 28, and 27 mm, respectively. The electrochemical tests including CV, EIS, and GCD exhibited the superior capacitive behaviour of NC. These results demonstrate that grown NC is an efficient material for electrochemical devices, water purification, and biomedical applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study delves into enhancing the mechanical properties and cost-effectiveness of self-healing cementitious materials through detailed investigation. It conducts a thorough characterization of ...different hybridized self-healing repair mortars, comprising a laboratory-prepared mortar and two commercial non-self-healing mortars, along with a commercial ready-mix self-healing repair mortar. By incorporating bacteria at varying levels of 1.5 % and 2.5 % as cement replacements, the study aims to reduce costs associated with the self-healing process. Additionally, a sustainability-focused hybridization is performed by combining the ready-mix self-healing repair mortar with the weakest of the three parent mixes. The research evaluates the impact of mortar composition on mechanical properties, particularly concerning the optimal proportion of self-healing agents to achieve maximum strength. Notably, the crack healing efficiency of bacterial-incorporated specimens exhibits significant effectiveness. The correlation between the mechanical properties of intact specimens and their crack healing efficacy is explored, uncovering the potential for creating an outstanding self-healing repair mortar with exceptional healing efficiency and robust mechanical performance. Furthermore, a comparative cost analysis and an overall performance evaluation using the Generalized Performance Index (GPI) demonstrate the feasibility of striking a balance between self-healing material costs and desired performance outcomes through the strategic approach of hybridization.
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•Comprehensive evaluation of self-healing repair mortars versus hybridized mortars.•Mechanical, microstructural, and cost analyses were performed on 14 mixes.•Hybridization leverages the performance and cost of self-healing cementitious materials.•Novel use of generalized performance index for mechanical, self-healing, and cost.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this study, pure ZnO and iron (Fe) and cobalt (Co) co-doped ZnO nanoparticles were synthesized by varying Fe and Co concentrations using the co-precipitation method. The physical properties of ...as-prepared samples were investigated through XRD, FTIR, SEM, and UV–vis spectroscopy. X-ray diffraction confirmed the strong influence of Fe and Co ions on structural parameters without disturbing the basic ZnO hexagonal structure. The microstructural study was executed by using the Scherrer, W–H, and SSP methods. FTIR confirmed the presence of Zn–O, and Zn–M–O (M = Fe, Co) vibrational modes, which further confirmed the successful incorporation of dopants ions. The energy bandgap (Eg) extracted from UV–vis spectra has shown red-shift (3.37–2.7 eV) for decreasing Fe contents, whereas blue-shift (3.37–3.39 eV) for increasing Co concentration. SEM was used to investigate surface morphology, which represents the high rate of agglomeration. The photocatalytic test was performed on grown samples against various dyes and also observed the effects of varying concentrations of Fe and Co ions. The maximum degradation efficiency (98.8%) at 6%Fe and 4%Co under direct sunlight in 60 min against methylene blue (MB) was achieved. The photocatalytic activity of optimized concentration (6%Fe and 4%Co) was further tested against cresol red (CR), methyl orange (MO), safranin-O (SO), rhodamine-B (RhB), and methyl red (MR) dyes. The maximum degradation efficiency against MR dye (96.0%) was observed. The antibacterial test against Staphylococcus aureus and Klebsiella pneumoniae bacterial strains have shown that co-doped ZnO nanoparticles have a higher activity as compared to pristine ZnO, and furthermore, the sample with 6%Fe and 4%Co concentration exposed the highest antibacterial actively for both bacterial strains.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The advancement of sunlight-driven metal oxide semiconductor-based, highly efficient photocatalysts for removing contaminants like dyes from wastewater remained a challenge. In this work, Pr/Cu ...dual-doped ZnO anchored with different rGO concentrations were synthesized by simple co-precipitation and ultrasonication route. The structural, morphological, and optical characterization of prepared materials was performed with different techniques and employed for degrading diverse kinds of dyes pollutants under natural sunlight illumination. The photodegradation efficiency after 40 min sunlight illumination towards Methyl Orange (MO) was 51.00, 75.00, and 99.76% for ZnPrCuO (S1), ZnPrCuO/rGO (1:1) (S2), and ZnPrCuO/rGO (1:2) (S3), respectively. The results suggested that the introduction of Pr/Cu and rGO significantly boosted the photodegradation ability of ZnO under sunlight. Especially, S3 nanocomposite exhibited the highest photodegradation of safranin-O (SO), Rhodamine-B (RhB), and methylene blue (MB) dyes, having degradation efficiency of 65.50, 91.40, and 99.80%, respectively, in 40 min. The scavenger test results exhibited that •OH and •O2− were the foremost active species in the photodegradation process. Moreover, the reusability experiments and tracing XRD after reusing samples revealed that the S1 catalyst has excellent recyclability (6th cycle). The reduction in energy bandgap and creation of impurity energy level by Pr/Cu doping leads to inhibit carrier pair recombination and effective charge transfer/separation. These findings revealed that Pr/Cu doping and rGO have the potential to enhance the visible light response of ZnO to eliminate dyes pollutants in wastewater with energy saving.
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•Development of ZnPrCuO/rGO nanocomposite photocatalyst.•Enhanced diverse dyes degradation in 40 min under natural sunlight.•Remarkable stability 6th cycles for degradation of MB dye.•Effective charge transfer/separation executed by rGO.•Efficient photocatalyst to eliminate dyes pollutants in wastewater with energy saving.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Nowadays, environmental pollution due to discharge of organic pollutants from food, textile, and pharmaceutical industries into clean water and development of contagious diseases due to pathogenic ...organisms provide impetus to material researcher to fabricate novel design for efficient photocatalyst and antimicrobial agents. In this regard, designing a core-shell heterojunction catalyst based on metal oxides is considered an auspicious approach. In present study, combating the problems of singular oxides, core-shell PANI-CeO2-Fe2O3–NiO nanocomposite (PCFN) and CeO2–Fe2O3–NiO nanocomposite (CFN) was synthesized through sol-gel and oxidative polymerization route with cetyletrimethylammonium bromide (CTAB) as surfactant. The XRD, FTIR, and Raman confirmed the formation of nanocomposites with core-shell morphology composed of PANI (shell) and oxides (Core) in PCFN with a particle size of 52 nm (TEM). Surprisingly, PCFN has lower band gap, e−/h+ recombination, and larger charge transfer character than CFN. The decomposition test using MB and MO dyes showed that PCFN degraded 99%, 98%, while CFN degraded only 73% and 54%, respectively, under 50 min sunlight illumination. The reusability was assessed up to 7th cycle for PCFN. The influence of operational parameters (catalyst dose, dye concentration, pH) was tested for PCFN. Further, the antimicrobial action against S. aureus (gram + ve), E. coli (gram -ve) were also tested. The supreme performance of PCFN has been credited to heterostructure dual Z-scheme formation and core-shell morphology supported with PANI, which suppresses the e−/h+ recombination process by promoting their separation. The present finding indicated that the PCFN is a promising modifier for bacterial disinfection and acts as a superb photocatalyst through core-shell formation with PANI support.
•Synthesis of core-shell PANI-CeO2-Fe2O3–NiO nanocomposite via solution method.•Enhanced photodegradation of MB and MO dyes under natural sunlight.•The higher ability to inhibit the growth of S. aureus and E. coli bacterial strains.•Dual Z-scheme heterostructure formation leads to better charge transfer.•Efficient catalyst for dye pollutant elimination and bacterial disinfection.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pristine CdO and chromium (Cr)-cobalt (Co) co-doped CdO nanowires via a facile co-precipitation protocol were synthesized and characterized with different analytical techniques to investigate its ...physical, photocatalytic, antibacterial, and electrochemical properties. The co-doping of Cr-Co into CdO matrix and their structural variations were confirmed by X-ray diffraction (XRD) data. Fourier transform infrared (FTIR) and Raman spectra also confirmed the doping of Cr and Co ions. The energy bandgap was extracted by employing different methods using UV–vis results, exhibited redshift by decreasing Co contents and blue shift by increasing Cr concentration. Scanning electron microscopy (SEM) images confirmed the preparation of nanowires. The photocatalytic and antibacterial experiments results showed the higher photodegradation efficiency against methylene blue (MB) (99.5%), methyl orange (MO) (90.6%), rhodamine-B (RhB) (87.5%), safranin-O (SF) (87.5%), and methyl red (MR) dyes (99.99%), after 60 min of sunlight illumination and the higher zone of inhibition (ZOI) against Klebsiella pneumoniae and Staphylococcus aureus for optimal doped Cd0.90Co0.05Cr0.05O (Cd4) sample. The recyclability tests using Cd4 catalyst were exhibited higher stability up to 5th cycles. The higher ability to decompose dyes and kill bacteria is due to the generation of reactive species, confirmed by the radical trapping experiments. The electrochemical measurements were revealed that the Cd4 sample has a higher specific capacitance of 500 F/ g− 1 at 10 mV/s scan rate, excellent energy density 72 Wh/Kg, and greater power density of 4800 W kg− 1 at a current density of 0.1 A/g. Furthermore, the properties of CdO can be tuned by co-doping for making it a useful material for photocatalyst, supercapacitors electrodes, and antibacterial applications.
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•Pristine CdO and Cr-Co co-doped CdO nanowires were synthesized via a facile co-precipitation method.•Different analytical techniques such as XRD, FTIR, Raman, UV–vis, IV, SEM, CV, EIS, and GCD were used.•Enhanced photocatalytic performance against various pollutants with stability upto 5th cycle was achieved.•Improved antibacterial characteristics against different human pathogenic bacterial strain was attained.•The higher specific capacitance, energy density, and power density at optimal loading of Cr and Co were obtained.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Novel direct dual Z-scheme ZnO-Er2O3-Nd2O3@rGO heterostructured nanocomposite along with simple ZnO-Er2O3-Nd2O3 nanocomposite was prepared by co-precipitation route. The X-ray diffraction pattern ...exhibited the diffraction peaks associated with ZnO (hexagonal), Er2O3 (cubic), and Nd2O3 (hexagonal) in both nanocomposites. The FTIR spectra further confirmed the formation of nanocomposites. The energy bandgap of simple and rGO decorated nanocomposites were 3.1 and 2.82 eV. The antibacterial characteristics of grown samples showed that the rGO anchored nanocomposite has higher antibacterial activity as compared to simple nanocomposite. The ZnO-Er2O3-Nd2O3@rGO nanocomposite exhibited higher photodegradation (97.0%) against methylene blue (MB) than simple nanocomposite (86.0%). The effectiveness of grown ZnO-Er2O3-Nd2O3@rGO nanocomposite as photocatalyst was also tested for degradation of other dyes such as RhB, MO, CR, and SO. The effect of operating parameters was investigated for ZnO-Er2O3-Nd2O3@rGO nanocomposite. A possible conventional heterojunction and Z-scheme for the degradation using ZnO-Er2O3-Nd2O3@rGO nanocomposite has been designed to elucidate the photocatalytic mechanism.
•ZnO-Er2O3-Nd2O3 and ZnO-Er2O3-Nd2O3@rGO nanocomposites successfully prepared.•The photocatalytic application was studied using MB, RhB, MO, CR and SO dyes.•The effect of operating parameters for the degradation of SO dye investigated.•The antibacterial activity against different bacterial strains was investigated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
