Engineering Applications Research Articles

Enhanced Bioactivity of Chitosan-Alginate-Riboflavin Liquid-Exfoliated Molybdenum Disulfide Nanosheets for Bone Tissue Engineering Applications

Enhanced Bioactivity of Chitosan-Alginate-Riboflavin Liquid-Exfoliated Molybdenum Disulfide Nanosheets for Bone Tissue Engineering Applications

Effect of various notch shape on Lamb wave scattering behaviour in a bent plate

Abstract The application of guided waves to investigate commonly used plate shapes in the aerospace, mechanical and civil industries are plates with bend shapes. This paper investigates the interaction of fundamental Lamb waves with notches in bent plates, commonly found in aerospace, mechanical, and civil engineering applications. These areas are particularly susceptible to failure due to defects such as cracks and notches, which often manifest as semi-circular corrosion patches or 900 notches. The presence of notches affects stress distribution, necessitating thorough analysis to prevent accidents. Accordingly, this paper focus on the interaction of fundamental Lamb waves through two types of notches that could be present inside a bent metal plate section. To explore this, a hybrid numerical framework is employed which combines Semi-Analytical Finite Elements (SAFE) with the Finite Element Method (FEM). A bent plate sections with various notch types is simulated using FEM, while SAFEs facilitate the definition of wave propagation through healthy regions of the plate. The study analyses the scattering behaviour of Lamb waves for different notch configurations and examines both fundamental modes over a specified frequency range. With a change in the interrogation signal parameters, there is a noticeable difference in the sensitivity of scattered waves with different notch types. Formulating a strategy for identifying and locating a notch inside a bent plate may need careful consideration of the important conclusions drawn. Understanding these interactions, aim of the paper is to enhance the integrity assessment of structural components subject to such defects.

An Ultra‐Short‐Term Multi‐Step Prediction Model for Wind Power Based on Sparrow Search Algorithm, Variational Mode Decomposition, Gated Recurrent Unit, and Support Vector Regression

ABSTRACTAccurate ultra‐short‐term wind power prediction techniques are crucial for ensuring the efficient and safe operation of wind farms and power systems. Combined models based on data decomposition‐prediction techniques have shown excellent performance in ultra‐short‐term wind power forecasting. This study introduces a novel ultra‐short‐term multi‐step prediction model for wind power, which integrates the sparrow search algorithm (SSA), variational mode decomposition (VMD), gated recurrent unit (GRU), and support vector regression (SVR). An optimization variational mode decomposition technique is developed by adaptively determining VMD hyperparameters using SSA. The optimization VMD decomposes the original wind power sequence into sub‐modes, and the resulting sequence of decomposed sub‐modes calculates permutation entropy (PE) values. Sub‐modes with similar PE values are combined, reorganized, and categorized into high‐frequency and low‐frequency. High‐frequency sub‐modes data with high complexity and non‐stationarity are predicted by the GRU neural network. Low‐frequency sub‐modes data with low complexity and strong nonlinearity are predicted with SVR. The proposed model was evaluated against seven others using three error metrics: MAE, RMSE, and R2, along with their corresponding enhancement percentages. Experimental results indicate that the proposed model extracts detailed and trend information from the wind power series more effectively and stably than the comparison models. It also demonstrates superior multi‐step prediction performance, offering significant value for practical engineering applications.

Advancing Electrical Engineering with Biomass-derived Carbon Materials: Applications, Innovations, and Future Directions.

The ongoing global shift towards sustainability in electrical engineering necessitates novel materials that offer both ecological and technical benefits. Biomass-derived carbon materials (BCMs) are emerging as cornerstones in this transition due to their sustainability, cost-effectiveness, and versatile properties. This review explores the expansive role of BCMs across various electrical engineering applications, emphasizing their transformative impact and potential in fostering a sustainable technological ecosystem. The fundamentals of BCMs are investigated, including their unique structures, diverse synthesis procedures, and significant electrical and electrochemical properties. A detailed examination of recent innovations in BCM applications for energy storage, such as batteries and supercapacitors, and their pivotal role in developing advanced electronic components like sensors, detectors, and electromagnetic interference shielding composites has been covered. BCMs offer superior electrical conductivities, tunable surface chemistries, and mechanical properties compared to traditional carbon sources. These can be further enhanced through innovative doping and functionalization techniques. Moreover, this review identifies challenges related to scalability and uniformity in properties and proposes future research directions to overcome these hurdles. By integrating insights from recent studies with a forward-looking perspective, this paper sets the stage for the next generation of electrical engineering solutions powered by biomass-derived materials, aligning technological advancement with environmental stewardship.

Tumor Cell-Specific Signal Processing Platform Controlled by ATP for Non-invasive Modulation of Cellular Behavior.

Regulating the spatial distribution of membrane receptors can artificially reprogram cellular behaviors, which play a critical biological role in various physiological and pathological processes. Herein, we construct a tumor cell-specific signal processing platform (TCS-SPP) for controlled promotion/inhibition of cellular-mesenchymal epithelial transition factor (c-Met) receptor dimerization to noninvasively modulate cellular behaviors. Upon the dual-aptamer recognition in the upstream input signal circuit (UISC) to discriminate target cancer cells, the membrane-anchored DNA signal processor (DSP) is activated for signal amplification via rolling circle amplification (RCA) followed by the working of an ATP molecular switch for signal conversion, achieving receptor modulation in the downstream output signal circuit (DOSC). Benefiting from the rigid structure of DSP, the protective effect, and spatial confinement effect of RCA products, this TCS-SPP has demonstrated good performance in accurately modulating cellular behavior such as cell migration, invasion, and proliferation, showing great potential for targeted cancer therapy and biomedical engineering applications.

Optimal Inspection and Maintenance Policy: Integrating a Continuous-Time Markov Chain into a Homing Problem

The state of a machine is modeled as a controlled continuous-time Markov chain. Moreover, the machine is being serviced at random times. The aim is to maximize the time until the machine must be repaired, while taking the maintenance costs into account. The dynamic programming equation satisfied by the value function is derived, enabling optimal decision-making regarding inspection rates, and special problems are solved explicitly. This approach minimizes direct maintenance costs along with potential failure expenses, establishing a robust methodology for determining inspection frequencies in reliability-centered maintenance. The results contribute to the advancement of maintenance strategies and provide explicit solutions for particular cases, offering ideas for application in reliability engineering.

Experimental study on flexural fatigue resistance of fiber-reinforced sustainable walnut shell ash mortar

In recent research on building materials, researchers have increasingly focused on replacing cement with agricultural waste. This approach offers significant advantages in terms of reducing global CO2 emissions and promoting the sustainability of building materials. In this paper, the use of the agricultural waste walnut shell ash (WSA) to partially replace cement in sustainable green mortars is explored. Specifically, equal amounts of WSA (5%, 10% and 15%) were used to replace cement. To offset the reduction in strength caused by the partial replacement of cement with WSA, basalt fibers were added to the mortar mixture. The effect of these fibers on the mechanical properties of the WSA-reinforced mortar was examined in compression tests, split tensile tests, and flexural fatigue cycle tests. In the flexural fatigue tests, the parameter and length of basalt fibers were varied and different stress levels (0.85, 0.8 and 0.75) were applied. The fatigue equations were developed using the Weibull model and p–s–n curves with a survival probability of 0.5 were derived. The results showed that the compressive strength and split tensile strength of the specimens increased with the addition of basalt fibers, with maximum values of 34.7 MPa and 3.8 MPa, respectively, and maximum increases of 8.78% and 21.95%, respectively. In addition, the average fatigue life of WSA mortar was 247,541 cycles, which increased by 139.26% when the stress level was 0.75, fiber length was 9 mm, and dosage was 0.3%. The linear regression fitting showed good correlation and provided valuable insights for practical engineering applications.

Methodology for Determining the Optimal Support Control Distance Based on the Deformation Increment Rate of Surrounding Rock and Its Engineering Application

Methodology for Determining the Optimal Support Control Distance Based on the Deformation Increment Rate of Surrounding Rock and Its Engineering Application

Advancements in the Engineering Modification of Sucrose Phosphorylase

Sucrose phosphorylase (SPase) is a member of the glycoside hydrolase family 13, catalyzing the reversible phosphorolysis of sucrose to produce α–glucose–1–phosphate and exhibiting transglycosylation activity toward multiple substrates. Its wide substrate specificity enables the synthesis of various glycosides, which are broadly applied in food, cosmetics, and pharmaceuticals. However, the industrial application of SPase is constrained by its poor thermostability and limited transglycosylation activity. Therefore, current research focuses on enhancing the thermostability and transglycosylation activity of SPase through efficient engineering strategies based on its crystal structure and catalytic mechanism. This paper systematically reviews the crystal structure and catalytic mechanism of SPase, outlines the application of protein engineering and immobilization strategies in improving the thermostability of SPase, and analyzes how modifications at key amino acid sites affect the synthesis of typical glycosylation products. It also summarizes the limitations of SPase engineering modification strategies and explores the potential of diversified approaches for SPase modification, highlighting its broad application prospects in industrial production and laying a solid foundation for further advancements in SPase engineering modification and its industrial application.

Impact of Thermal Energy on Water and Ethylene Glycol (50:50)-Based Rotating Hybrid Nanofluid Past A Riga Surface with Radiation, Homogeneous and Heterogeneous Reactions

Hybrid nanofluid is crucial in improving the efficiency of heat transmission in thermal engineering applications, particularly the cooling of electrical equipment, heat exchangers, fuel cells, printing machines, etc. This study sought to investigate the augmentation of heat and mass transmission by the use of a rotating hybrid nanofluid consisting of a mixture of gold and silver nanoparticles suspended in water and ethylene glycol (50:50) past a heated Riga surface with velocity slip and suction. The energy equation is constructed using nonlinear radiation and heat consumption. The impact of both homogeneous and heterogeneous processes on the hybrid nanofluid is also explored. The governing mathematical model begins with partial differential equations that are converted into ordinary differential equations using a suitable conversion technique. The results of numerical computations are recorded as graphs and tables using the bvp4c scheme in MATLAB. It is noticed that both directional velocities undergo significant negative changes as a result of enhanced values of the rotational parameter. The higher levels of the radiation parameter resulted in significant enhancements in the thermal profile. The falling behavior of the nanoparticle concentration profile is recorded against a greater quantity of both chemical reaction parameters. Based on our analysis, when the Biot number changes from 0.4 to 0.8, the most significant heat transmission gradient occurs.

Modeling Borehole Resistivity Logs with Exponentially Graded Multilayered Soil Inversion for Electrical Engineering Applications

In this paper, we present the application of a special soil resistivity model, the Exponentially Graded Multilayered Soil model, to the interpretation of Borehole Resistivity Logging surveys. The model, which was recently introduced by the authors, offers an alternative to the interpretation provided by constant resistivity layer models. The model is applied to synthetic soil surveys as well as to a real survey that is not satisfactorily interpreted using conventional models. This model aids in the design and calculation of grounding systems in electrical engineering, providing an alternative to calculations performed by traditional layered models.

Microscopic Modeling Techniques for Steel Fiber Reinforced Concrete: Applications and Future Directions

This article reviews micro-modeling methods for steel fiber-reinforced concrete (SFRC), including finite element, discrete element, and computational fluid dynamics approaches, to analyze its mechanical and structural behavior. The models offer predictive insights on stress response, crack propagation, and durability in SFRC, particularly in high-stress structural applications. This study discusses the limitations of current modeling practices, such as high computational demand and parameter determination challenges, and suggests future improvements to enhance simulation accuracy and scalability. This review aims to support the advancement of SFRC in structural engineering applications.

Continuous evolution of user-defined genes at 1 million times the genomic mutation rate.

When nature evolves a gene over eons at scale, it produces a diversity of homologous sequences with patterns of conservation and change that contain rich structural, functional, and historical information about the gene. However, natural gene diversity accumulates slowly and likely excludes large regions of functional sequence space, limiting the information that is encoded and extractable. We introduce upgraded orthogonal DNA replication (OrthoRep) systems that radically accelerate the evolution of chosen genes under selection in yeast. When applied to a maladapted biosynthetic enzyme, we obtained collections of extensively diverged sequences with patterns that revealed structural and environmental constraints shaping the enzyme's activity. Our upgraded OrthoRep systems should support the discovery of factors influencing gene evolution, uncover previously unknown regions of fitness landscapes, and find broad applications in biomolecular engineering.

Heat and mass transfer analysis in flow of Walter's B nanofluid: A numerical study of dual solutions

AbstractThis study investigates the behavior of Walter's liquid B fluid over a biaxially stretching/shrinking surface for Homann stagnation point flow, focusing on the rheological properties that are crucial for understanding physical phenomena in engineering and industrial processes. The problem is modeled using Buongiorno's model in the presence of a permeable surface subject to heat generation/absorption, Ohmic heating, and chemical reactions influenced by Arrhenius activation energy. The governing partial differential equations are solved numerically using an appropriate similarity transformation, and the results are graphically analyzed via MATLAB's bvp5c solver. The study highlights the importance of characterizing the intricate properties of viscoelastic fluids, with potential applications in biomedical engineering and materials science. The findings reveal the coexistence of two distinct flow regimes and dual solutions are obtained. It is noted that the activation energy parameter is shown to enhance mass distribution in both solutions, while chemical reactions accelerate reactant conversion but reduce mass distribution. Additionally, an increase in viscoelasticity shifts the fluid's behavior towards elasticity, creating greater resistance to shear deformation and reducing both velocity profiles.

Interfacial-Polarization Engineering in BNT-Based Bulk Ceramics for Ultrahigh Energy-Storage Density.

Ceramic capacitors, known for their exceptional energy-storage performance (ESP), are crucial components in high-pulsed power systems. However, their ESP is significantly constrained by breakdown strength (Eb), which is influenced by interfacial polarization. This study delves into the physics, characterization, and application of interfacial polarization. The findings indicate that key factors affecting ESP, such as grain size, relaxor factor, and bandgap, are intrinsically linked to interfacial polarization, establishing it as the most critical determinant of ESP. To demonstrate the practical applications of interfacial polarization engineering, lead-free ceramics of (1-x)(0.94Bi0.5Na0.5TiO3-0.06BaTiO3)-xCa0.7Bi0.2(Sn0.5Ti0.5)O3 (abbreviated as (BNT-BT)-xCBST is designed, where x = 0, 0.1, 0.15, 0.2, and 0.25). The (BNT-BT)-0.25CBST sample, with a thickness of 120µm, achieved an ultrahigh recoverable energy-storage density (Wrec) of 12.2Jcm-3 and a high efficient (η) of 88.8%, along with excellent temperature/frequency stability and outstanding charge/discharge performance. The remarkable ESP is attributed to the suppression of interfacial polarization, which significantly enhances Eb. This work highlights the pivotal role of interfacial polarization engineering in the development of energy-storage ceramics with superior comprehensive performance.

Influence of the PAN:PEO Ratio on the Morphology of Needleless Electrospun Nanofiber Mats Before and After Carbonization

Nanofiber mats with a high surface-to-volume ratio can be prepared by electrospinning. The Porosity is sometimes reported to be tunable by blending different materials, e.g., water-soluble poly(ethylene oxide) (PEO) with not water-soluble poly(acrylonitrile) (PAN). Here, nanofiber mats were electrospun from different PAN:PEO ratios, using a wire-based electrospinning machine “Nanospider Lab”. Investigations of the as-spun nanofiber mats as well as of membranes after washing off the water-soluble PEO by scanning electron microscopy (SEM) revealed severe differences in the nanofiber mat morphologies, such as varying fiber diameters and especially non-fibrous areas in the carbonized nanofiber mats, depending on the amount of PEO in the nanofiber mat as well as the molecular weight of the PEO. Similarly, the ratio and molecular weight of PEO influenced the results of stabilization and carbonization. This paper discusses the possibility of tailoring nanofiber porosity for the potential use of PAN nanofiber mats in tissue engineering, filtration, and other applications.

Pulse electroosmotic flow of Newtonian fluids in parallel plate microchannels under triangular and half-sinusoidal pulse electric fields

Unlike the conventional electroosmotic flow (EOF) driven by direct current and alternating current electric fields, this study investigates the pulse EOF of Newtonian fluids through a parallel plate microchannel actuated by pulse electric fields. Specifically, the pulses considered encompass triangular and half-sinusoidal pulse waves. By applying the Laplace transform method and the residual theorem, the analytical solutions for the velocity and volumetric flow rate of the pulse EOF associated with these two pulse waves are derived, respectively. The influence of pulse width a¯ and electrokinetic width K on velocity is further considered, while the volumetric flow rate as a function of time t¯ and electrokinetic width K is examined separately. A comparison of the volumetric flow rates related to these two pulse waves under varying parameters is also conducted. The research findings indicate that irrespective of the pulse wave, a broader pulse width results in a prolonged period and increased amplitude of the velocity profile. Elevating the electrokinetic width yields higher near-wall velocities, with negligible effect on near-center velocities. It is noteworthy that regardless of the electrokinetic width, the near-wall velocity exceeds that of the near-center during the first half-cycle, while the situation reverses during the second half-cycle. The volumetric flow rate varies periodically with time, initially surging rapidly with electrokinetic width before gradually stabilizing at a constant level. More interestingly, independent of pulse width and electrokinetic width, the volumetric flow rates linked to the half-sinusoidal pulse wave consistently surpass those of the triangular pulse wave. For any pulse width, the volumetric flow rates corresponding to the two pulse waves grow with higher electrokinetic widths, especially prominent at alternating intervals of the two half-cycles within a complete cycle. These findings have important implications for improving the design and optimization of microfluidic devices in engineering and biomedical applications utilizing pulse EOF.

Medical and Engineering Applications for Estimation and Prediction of a New Competing Risks Model: A Bayesian Approach

The Bayesian approach offers a flexible, interpretable and powerful framework for statistical analysis, making it a valuable tool to help in making optimal decisions under uncertainty. It incorporates prior knowledge or beliefs about the parameters, which can lead to more accurate and informative results. Also, it offers credible intervals as a measure of uncertainty, which are often more interpretable than confidence intervals. Hence, the Bayesian approach is utilized to estimate the parameters, reliability function, hazard rate function and reversed hazard rate function of a new competing risks model. A squared error loss function as a symmetric loss function and a linear exponential loss function as an asymmetric loss function are employed to derive the Bayesian estimators. Credible intervals of the parameters, reliability function, hazard rate function and reversed hazard rate function are obtained. Predicting future observations is important in many fields, from finance and weather forecasting to healthcare and engineering. Thus, two-sample prediction (as a special case of the multi-sample prediction) for future observation is considered. An adaptive Metropolis algorithm is applied to conduct a simulation study to evaluate the performance of the Bayes estimates and predictors. Moreover, two applications of medical and engineering data sets are used to test and validate the theoretical results, ensuring that they are accurate, applicable to real-world scenarios and contribute to the understanding of the world and inform decision-making.

Mechanical Behavior of 3D-Printed Schwarz Diamond-Structured Scaffolds for Tissue Engineering Applications

Mechanical Behavior of 3D-Printed Schwarz Diamond-Structured Scaffolds for Tissue Engineering Applications

Bioactive Peptide Hydrogel Scaffold with High Fluidity, Thermosensitivity, and Neurotropism in 3D Spatial Structure for Promoted Repair of Spinal Cord Injury.

Spinal cord injury (SCI) has been considered a clinically challenging disease that is characterized by local disturbance of the microenvironment, which inhibits post-injury neural regeneration. The simulation of a microenvironment conducive to the regeneration of spinal cord is beneficial for SCI repair. In this study, bioactive composite hydrogels are developed that mimic the regenerative microenvironment of spinal cord for enhanced SCI repair. The fabricated composite hydrogels (CRP) based on chitosan (CS), RADA16 nanofibers, and nerve-promoted peptide (PPFLMLLKGSTR) exhibit excellent injectability, superior biodegradability and biocompatibility. In addition, the CRP hydrogels can formquickly (a few minutes) by mixing three components at human body temperature, showing high potential as a biomimetic matrix for in situ repair of SCI. The in vitro studies demonstrate that the CRP hydrogels can not only promote the proliferation and migration of bone marrow mesenchymal stem cells but also induce the proliferation and differentiation of neural stem cells (NSCs) into neurons. Meanwhile, the hydrogels reveal the efficiency of protecting neurons and promoting axonal growth. Furthermore, the in vivo tests prove that the CRP hydrogels can reduce post-SCI inflammatory responses, inhibit reactive astrocyte over-proliferation, and promote the migration, proliferation, and differentiation of endogenous NSCs, which agree well with the in vitro results. The pre-clinical test demonstrates that the CRP hydrogels restore the motor function in completely transected spinal cord rats, and the SCI repair mechanism may involve the activation of the PI3K/AKT/mTOR pathway. It is believed that the strategies shown in this work will be valuable for the design and synthesis of novel hydrogels for biomedical and tissue engineering applications.