Step Scheme Research Articles

Empowering wastewater treatment with step scheme heterojunction ternary nanocomposites for photocatalytic degradation of nitrophenol

The ongoing challenge of water pollution necessitates innovative approaches to remove organic contaminants from wastewater. In this work, new two-dimensional S-scheme heterojunction photocatalysts Bi2O3/CdS and MoS2/Bi2O3/CdS that are intended for the effective photocatalytic destruction of 4-nitrophenol, a dangerous organic pollutant, are synthesized and characterized. Utilizing a solvothermal method, successfully generated these ternary nanocomposites, which were characterized through various techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electronmicroscopy (HRTEM), Brunauer-Emmett-Telle (BET) and diffuse reflectance spectroscopy (DRS). Our results demonstrated that the Bi2O3/CdS heterojunction achieved an 86% degradation rate of 4-nitrophenol, while the MoS2/Bi2O3/CdS composite exhibited exceptional photocatalytic performance, achieving nearly complete degradation (99%) within 120 min under visible light irradiation. Most importantly the improved photocatalytic activity of MoS2/Bi2O3/CdS heterojunction originated from the release of internal electric field in S-scheme heterojunction. This enhanced activity is attributable to the synergistic effects of the heterojunctions that facilitate more effective charge separation and generation with more OP and RP confirmed the composite synthesis using S-scheme. The S-scheme is further confirmed by XPS, DRS, XPS-VB and photocurrent response. These findings highlight the promising application of these advanced photocatalysts in real-world wastewater treatment processes, offering a sustainable solution to combat water pollution.

Designing an innovative 2D/2D step scheme α-Fe2O3/BiOBr/MoS2 ternary integrated heterojunction with unparalleled visible-light-induced remarkable photocatalytic H2 evolution

Designing an innovative 2D/2D step scheme α-Fe2O3/BiOBr/MoS2 ternary integrated heterojunction with unparalleled visible-light-induced remarkable photocatalytic H2 evolution

Conservative treatment of injuries to the cervical spine : Mobilization or immobilization

Many injuries to the cervical spine can be treated conservatively. Treatment options include early functional, mobilizing and immobilizing procedures. If astructural injury can be ruled out by morphological imaging, early functional mobilization should be performed in combination with adequate analgesia according to the World Health Organization (WHO) step by step scheme to avoid chronification. If astructural injury to the cervical spine is present, astability test is crucial for the decision on treatment. Stable fractures include, for example, typesI, II and Vfractures of the atlas according to Gehweiler, typesI and IIIfractures of the dens axis according to Anderson and D'Alonzo and type Afractures of the subaxial cervical spine according to the AO. If the results of the imaging examination are inconclusive, functional imaging should be performed. If the injury is stable, external immobilization can be used for conservative treatment. Semirigid and rigid cervical orthotic devices as well as Minerva corsets and the halo fixator are available for this purpose. The degree of immobilization increases with the invasiveness of the procedure. Immobilization should be carried out under clinical and radiological monitoring until the injury has healed. An increase or persistence of symptoms during conservative treatment indicates treatment failure and should result in follow-up imaging. Immobilizing treatment should also be accompanied by isometric physiotherapeutic exercise and adequate analgesic treatment. In adult patients the external stabilization should be gradually reduced through physiotherapeutic exercise after completion of the immobilization treatment.

A Parallel-GPU DGTD Algorithm with a Third-Order LTS Scheme for Solving Multi-Scale Electromagnetic Problems

This paper presents a novel parallel-GPU discontinuous Galerkin time domain (DGTD) method with a third-order local time stepping (LTS) scheme for the solution of multi-scale electromagnetic problems. The parallel-GPU implementations were developed based on NVIDIA’s recommendations to guarantee the optimal GPU performance, and an LTS scheme based on the third-order Runge–Kutta (RK3) method was used to accelerate the solution of multi-scale problems further. This LTS scheme used third-order interpolation polynomials to ensure the continuity of the time solution. The numerical results indicate that the strategy with the parallel-GPU DGTD and LTS maintains the order of precision of standard global time stepping (GTS) and reduces the execution time by about 78% for a complex multi-scale electromagnetic scattering problem.

Model‐assisted analysis of covariance estimators for stepped wedge cluster randomized experiments

AbstractStepped wedge cluster randomized experiments (SW‐CREs) represent a class of unidirectional crossover designs. Although SW‐CREs have become popular, definitions of estimands and robust methods to target estimands under the potential outcomes framework remain insufficient. To address this gap, we describe a class of estimands that explicitly acknowledge the multilevel data structure in SW‐CREs and highlight three typical members of the estimand class that are interpretable. We then introduce four analysis of covariance (ANCOVA) working models to achieve estimand‐aligned analyses with covariate adjustment. Each ANCOVA estimator is model‐assisted, as its point estimator is consistent even when the working model is misspecified. Under the stepped wedge randomization scheme, we establish the finite population Central Limit Theorem for each estimator. We study the finite‐sample operating characteristics of the ANCOVA estimators in simulations and illustrate their application by analyzing the Washington State Expedited Partner Therapy study.

The novel ribosome biogenesis inhibitor usnic acid blocks nucleolar pre-60S maturation

The formation of new ribosomes is tightly coordinated with cell growth and proliferation. In eukaryotes, the correct assembly of all ribosomal proteins and RNAs follows an intricate scheme of maturation and rearrangement steps across three cellular compartments: the nucleolus, nucleoplasm, and cytoplasm. We demonstrate that usnic acid, a lichen secondary metabolite, inhibits the maturation of the large ribosomal subunit in yeast. We combine biochemical characterization of pre-ribosomal particles with a quantitative single-particle cryo-EM approach to monitor changes in nucleolar particle populations upon drug treatment. Usnic acid rapidly blocks the transition from nucleolar state B to C of Nsa1-associated pre-ribosomes, depleting key maturation factors such as Dbp10 and hindering pre-rRNA processing. This primary nucleolar block rapidly rebounds on earlier stages of the pathway which highlights the regulatory linkages between different steps. In summary, we provide an in-depth characterization of the effect of usnic acid on ribosome biogenesis, which may have implications for its reported anti-cancer activities.

Compact narrow slot antenna with stable radiation pattern and wide bandwidth

One of the most crucial parameters for any antenna is bandwidth. Over the whole extended bandwidth, the antenna achieves a high gain of 5dBi and a steady bidirectional radiation pattern. A novel design concept for increasing bandwidth and maintaining a consistent radiation pattern has been proposed for the radiated fields of a slot antenna. First, the radiated fields of the standard slot antenna are examined theoretically using characteristic modes (CMs). Its three CMs vibrate at 2.45, 4.78, and 7.17 GHz, respectively, according to the results. CM1 and CM3 both continue to emit radiation in both directions, but CM2 generates a radiation null in the broadside direction. After that, the linear slot is appropriately folded to change CM2’s non-bidirectional pattern into a bidirectional one, allowing for the broad bandwidth use of the neighbouring CM1 and CM2. The narrow slot is then used to create the stepped scheme, which reallocates these dual modes in close proximity to one another. By using these designs, the antenna’s radiation pattern consistency and small size of 0.022λo can be preserved, but its impedance bandwidth can be significantly expanded. After that, the proposed antenna is constructed and assessed. Measurements show that the antenna has a broad bandwidth (|S11|<−10 dB) of around 35.14%, covering the frequency range of 3.3 to 4.6 GHz.

Convergence of a double step scheme for a class of second order Clarke subdifferential inclusions

In this paper we deal with a second order evolution inclusion involving a multivalued term generated by a Clarke subdifferential of a locally Lipschitz potential. For this problem we construct a double step time-semidiscrete approximation, known as the Rothe scheme. We study a sequence of solutions of the semidiscrete approximate problems and provide its weak convergence to a limit element that is a solution of the original problem.

Electron deficient Bi3+δ serves as N2 absorption sites and inhibits carriers recombination to enhance N2 photo-fixation in BiOBr/TiO2 S-scheme heterojunction

Efficient carriers separation and multiple nitrogen (N2) activation sites are essential for N2 photo-fixation. Here, we found that the BiOBr/TiO2 (BBTO) displayed an attractive reversible photochromism (white → grey) due to the generation of electron deficient Bi3+δ, which was produced by the hole trapping of Bi3+ under light irradiation. Interestingly, more Bi3+δ were detected in the BBTO heterojunction than in pure BiOBr, attributing that the hole trapping was promoted by the built-in electric field in the Step scheme (S-scheme) heterojunction. In the BBTO, the electron deficient Bi3+δ enhanced carriers separation and served as the reactive active site to adsorb more N2. Consequently, the BBTO possessed an excellent N2 photo-fixation activity (191 μmol gcat−1 h−1), which was 7.7 and 18 times higher than that of pure BiOBr (24.8 μmol gcat−1 h−1) and TiO2 (10.6 μmol gcat−1 h−1), respectively. Therefore, this work provides a new perspective for enhancing N2 photo-fixation by the electron deficient photocatalysts with S-scheme heterojunction.

Generalized high-order iterative methods for solutions of nonlinear systems and their applications

&lt;abstract&gt;&lt;p&gt;In this paper, we have constructed a family of three-step methods with sixth-order convergence and a novel approach to enhance the convergence order $ p $ of iterative methods for systems of nonlinear equations. Additionally, we propose a three-step scheme with convergence order $ p+3 $ (for $ p\geq3 $) and have extended it to a generalized $ (m+2) $-step scheme by merely incorporating one additional function evaluation, thus achieving convergence orders up to $ p+3m $, $ m\in\mathbb{N} $. We also provide a thorough local convergence analysis in Banach spaces, including the convergence radius and uniqueness results, under the assumption of a Lipschitz-continuous Fréchet derivative. Theoretical findings have been validated through numerical experiments. Lastly, the performance of these methods is showcased through the analysis of their basins of attraction and their application to systems of nonlinear equations.&lt;/p&gt;&lt;/abstract&gt;

Fractional Steps Scheme to Approximate the Phase Field Transition System Endowed with Inhomogeneous/Homogeneous Cauchy-Neumann/Neumann Boundary Conditions

Here, we consider the phase field transition system (a nonlinear system of parabolic type) introduced by Caginalp to distinguish between the phases of the material that are involved in the solidification process. We start by investigating the solvability of such boundary value problems in the class Wp1,2(Q)×Wν1,2(Q). One proves the existence, the regularity, and the uniqueness of solutions, in the presence of the cubic nonlinearity type. On the basis of the convergence of an iterative scheme of the fractional steps type, a conceptual numerical algorithm, alg-frac_sec-ord-varphi_PHT, is elaborated in order to approximate the solution of the nonlinear parabolic problem. The advantage of such an approach is that the new method simplifies the numerical computations due to its decoupling feature. An example of the numerical implementation of the principal step in the conceptual algorithm is also reported. Some conclusions are given are also given as new directions to extend the results and methods presented in the present paper.

Efficacious Extraction and Purification Technique of a Potential Antimycobacterial Bacteriocin Produced by Bacillus subtilis (MK733983) of Ethnomedicinal Origin.

The rapid proliferation of antibiotic-resistant microbes has imposed an urgent need for development of novel antimicrobial agents with diverse mechanisms. This study reports a novel extraction method with salting-in and salting-out method for obtaining potential bacteriocin from Bacillus subtilis (MK733983) of ethnomedicinal origin. This technique extracted bacteriocin with desired antimicrobial peptide moieties that showed creditable minimum inhibitory concentrations, thermostability and efficacy compared to all other extraction protocols attempted. Further study used a unique scheme of steps in RP-HPLC purification process using methanol-water as solvents for the bacteriocin that achieved an outstanding antimicrobial activity against Staphylococcus aureus (MTCC 737). The bacteriocin is sensitive to proteases, confirming its proteinaceous nature and showed promising heat stability up to 70°C for 10min. Bacteriocin extracted from a series of ammonium sulphate precipitation showed MIC values 350µg and 300µg for Mycobacterium smegmatis and Staphylococcus aureus respectively. On the other hand, bacteriocin extracted by using chloroform showed MIC values 400µg and 300µg for M. smegmatis and Staphylococcus aureus. All the results implicate the efficacy of bacteriocin and future prospect as an effective antimicrobial agent.

Optimal scheduling of electricity-gas-heat-hydrogen integrated energy system considering carbon transaction cost

Aim: To improve energy efficiency, optimize the operation of equipment, and reduce the carbon emission of the integrated energy system (IES), an IES low-carbon operation strategy is proposed. Methods: This paper comprehensively considers the influence of the stepped carbon trading scheme, the wind generation and load forecasting represented by fuzzy parameters, and the operation strategy of energy storage equipment with flexible space margin on the optimal scheduling of IES. Based on this, a low-carbon operation target with the minimum sum of power purchase cost, gas purchase cost, carbon emission cost, and abandoned wind cost is constructed. Results: Five scenarios are compared and analyzed. The effects of different carbon emission penalty strategies and wind power output and load uncertainties on benefits are analyzed. The feasibility of the proposed scheme is verified by the simulation results of a numerical example. Conclusion: The stepwise carbon trading mechanism can better guide the effect of carbon emission reduction compared with the traditional carbon trading pricing model.

Hydrazine -functionalized perylene diimide integrated Ti3+ self-doped TiO2 heterostructure for visible light-driven photocatalytic H2 evolution

Solar light-powered photocatalytic reactions for highly efficient hydrogen evolution remain a formidable challenge. Herein, a hydrazine-functionalized perylene diimide derivative (HPDI) supramolecular aggregates were incorporated into a Ti3+ self-doped TiO2 (Ti3+-TiO2) by solvent mixing method for highly efficient photocatalytic hydrogen production. The integration of HPDI effectively minimized the electron transfer path and improved the photoelectrochemical activity through π-π stacking of perylene core and hydrogen bonding of the terminal moiety with the Ti3+-TiO2. Further, the Ti3+-TiO2 formed by the partial hydrolysis of titanium isopropoxide (TTIP) followed by calcination also introduces Ti3+ bound states in TiO2 forming oxygen vacancies. It is demonstrated that HPDI with π-π stacking structure along with j-aggregation effectively improve the light absorption in the visible region. The photocatalytic studies for hydrogen production showed a successful formation of the step scheme mechanism in HPDI incorporated Ti3+-TiO2 system and it exhibited a superior hydrogen production efficiency of 1390 μmol/g, which is four-folds higher than bare TiO2. Thus, this work paves the way to design molecular structures as efficient photocatalysts for hydrogen production.

Modeling of Non-Isothermal Viscoelastic-Viscoplastic Deformation of Bending Reinforced Plates

A model of non-isothermal viscoelastic-viscoplastic deformation of multidirectionally reinforced flexible plates has been developed. The viscoplastic deformation of isotropic materials of the composition is described by the relations of the flow theory with isotropic hardening, which take into account the dependences of the loading functions on temperature and strain rate intensity. The viscoelastic behavior of the composition components is described by the equations of the Maxwell–Boltzmann model. The weakened resistance of reinforced plates to transverse shifts is modeled by the Ambartsumian bending theory relations, and the geometric nonlinearity is modeled in the Karman approximation. The connection between the thermophysical and mechanical components of the problem of inelastic dynamic deformation of reinforced plates is taken into account. The temperature over the thickness of structures is approximated by a 7th order polynomial. The numerical solution of the formulated nonlinear two-dimensional problem is constructed using an explicit scheme of time steps. The viscoelastic-viscoplastic dynamic behavior of a relatively thin glass-plastic plate is studied with and without allowance for the thermal response in it. The structure is loaded transversely with an air blast wave. It is shown that the failure to take into account the thermal response in a fiberglass plate can significantly distort the calculated fields of residual deformations of the components of its composition, despite the fact that the maximum heating of such a structure does not exceed 10°C. Viscoelastic-plastic calculations, when the sensitivity of the composite materials to the rate of their deformation can be neglected, can reasonably be carried out without taking into account the thermal response of the composite plate, if there are no external heat sources of non-mechanical origin.

Non-relaxed finite volume fractional step schemes for unsteady incompressible flows

Non-relaxed finite volume fractional step schemes for unsteady incompressible flows

A second-order bulk–surface splitting for parabolic problems with dynamic boundary conditions

Abstract This paper introduces a novel approach for the construction of bulk–surface splitting schemes for semilinear parabolic partial differential equations with dynamic boundary conditions. The proposed construction is based on a reformulation of the system as a partial differential–algebraic equation and the inclusion of certain delay terms for the decoupling. To obtain a fully discrete scheme, the splitting approach is combined with finite elements in space and a backward differentiation formula in time. Within this paper, we focus on the second-order case, resulting in a $3$-step scheme. We prove second-order convergence under the assumption of a weak CFL-type condition and confirm the theoretical findings by numerical experiments. Moreover, we illustrate the potential for higher-order splitting schemes numerically.

Computational modelling of built-up cold-formed steel columns and parametric studies

The paper develops a detailed finite-element model for the reliable nonlinear collapse analysis of built-up cold-formed steel columns with discrete fastener connections. First, the main components of the computational model are discussed, including their available options and comparison between their results, followed by a rational justification for the options chosen in this study. Specifically, a detailed theoretical background is provided with conclusive comparisons of the options for enforcing end support conditions, applying contact conditions between the constituent plates, selecting connection elements for representing intermediate screw fasteners, and finally, the incremental load stepping and nonlinear solution schemes. The accuracy and performance of the proposed FE modelling strategy are verified against the experimental data, contributing to the calibration of the influencing parameters. The predictions of the proposed methodology are shown to be in excellent agreement with the test data in terms of the failure mode and the inelastic capacity curve up to ultimate capacity and beyond. Upon its successful calibration, the FE model is utilised to perform extensive parametric studies into the effects of various design parameters on the ultimate strength of built-up columns. This includes practical variations of cross-section dimensions, sectional slenderness, built-up section geometry, and fastener spacing. The parametric study results suggest a meaningful dependency of the ultimate capacity of built-up sections on the fastener spacing ratio, the critical buckling half-wavelength of the built-up section and the relative number of restrained components in the built-up configuration undergoing sectional buckling.

A Study on Awareness of Education at Door Step (Illam Thedi Kalvi) Scheme among Primary School Parents in Kumbakonam Taluk

This study aimed to assess the level of awareness of the EDUCATION AT DOOR STEP ( Illam Thedi Kalvi ) scheme among parents of primary school students in Kumbakonam Taluk in Thanjavur District. The EDUCATION AT DOOR STEP scheme was launched by the Tamil Nadu government to provide education to children of migrant workers who often miss out on schooling due to frequent relocation. The study was conducted in eight primary schools of Kumbakonam Taluk using a survey questionnaire. A total of 232 respondents were selected through a random sampling technique. The results showed that the awareness level of the Education at Door Step scheme was relatively low, with only 46% of parents of primary school students having heard about the scheme. Among those who were aware of the scheme, only 29% knew the details of the scheme, such as the eligibility criteria and the benefits provided. The study also found that there was a significant association between the level of education and awareness of the Education at Door Step scheme. Those with higher education were more likely to have heard about the scheme and understood its benefits. The study recommends that the government should conduct more awareness campaigns to reach out to parents of primary school students especially rural area people and especially those with lower levels of education, and also ensure that all eligible children are enrolled in the EDUCATION AT DOOR STEP scheme.

A Review of the Some Fixed Point Theorems for Different Kinds of Maps

The focus of this article, reviewed a generalized of contraction mapping and nonexpansive maps and recall some theorems about the existence and uniqueness of common fixed point and coincidence fixed-point for such maps under some conditions. Moreover, some schemes of different types as one-step schemes ,two-step schemes and three step schemes (Mann scheme algorithm, Ishukawa scheme algorithm, noor scheme algorithm, .scheme algorithm, scheme algorithm Modified scheme algorithm arahan scheme algorithm and others. The convergence of these schemes has been studied .On the other hands, We also reviewed the convergence, valence and stability theories of different types of near-plots in convex metric space.