alexandria engineering journal最新文献

In the context of the San Gavain hydroelectric power station diversion tunnel project in Peru, this paper studies the surrounding rock instability mechanism using a combination of numerical simulation methods and model test and presents the enclosing rock instability criterion based on the catastrophe model. The study demonstrates that the distribution of stress and displacement during tunnel excavation is more affected by the presence of laminated joints; the thinner the layer thickness, the more prominent the influence of laminations, and the higher the deformation of the surrounding rock. With the increase in layer thickness, the resultant displacement shows the law of gradual decrease; when the layer thickness is greater than 16 cm, the rate of decrease gradually slows down, and the maximum displacement is 0.201 mm. The failure mode of the layered perimeter rock tunnel with a 45° inclination angle primarily shows up as tensile deformation at the left arch shoulder and shear slip deformation at the right arch foot under the combined action of blasting disturbance load and excavation. Based on the instability analysis of the fold catastrophe model and cups catastrophe model, the influence of bending deformation between layers of surrounding rock is generally greater than shear slip deformation. The instability criterion Δ＜0 exists in all working conditions, bending instability damage may occur in all cases. When the layer thickness is greater than 24 cm, the shear slip instability criterion is greater than zero for 0–2 ms, and the system is always in a stable state, and when the layer thickness is less than 24 cm, the system may be destabilized at 1.5 ms.

Green synthesis of gold nanoparticles (AuNPs) using Ginkgo biloba leaf aqueous extract was optimized by response surface methodology to yield monodispersed, crystalline nanoparticles of 18 ± 4 nm diameter. Fourier transform infrared spectroscopy confirmed capping by flavonoids, terpenoids and polyphenols providing stability for over 6 months. The biosynthesized AuNPs exhibited promising in vitro dose and time-dependent antiproliferative effects against human nasopharyngeal carcinoma CNE1 cells with IC50 reducing from 65.7 to 39.2 μg/mL over 24–72 hrs. Distinct cytoplasmic damage was observed under microscope. Treatment with 50 μg/mL AuNPs for 48 hrs dramatically upregulated pro-apoptotic Bax, Caspase-3 and p53 by 8.7, 6.5 and 4.3 fold respectively while downregulating anti-apoptotic Bcl-2 by 11.2 fold, indicating apoptosis induction via mitochondrial intrinsic pathway. The green fabricated G. biloba AuNPs displayed preferential toxicity towards carcinoma cells compared to normal fibroblasts, indicating potential for targeted nasopharyngeal cancer therapy.

The presented work concerns with some novel solutions of the (2+1)-dimensional Boussinesq equation (BE), which acts as an important model for shallow water wave. Some resonant soliton solutions such as the X-shape soliton (XSS) and Y-shape soliton (YSS) solutions are developed via imposing the resonant conditions on the N-soliton solutions (N-SSs) that developed by the Hirota bilinear approach(HBA). Based on the XSS and YSS solutions, the novel hybrid interactions including the interaction between the 1-soliton and the YSS, the interaction between two YSS solutions are extracted. In addition, the complex N-SSs are also explored and discussed. Finally, the travelling wave solutions including the bright solitary and kinky solitary wave solutions are studied by employing the Bernoulli sub-equation function method (BSEFM). The graphs of the attained solutions are drawn to show the physical properties. The findings of this study are expected to help us apprehend the dynamics of the (2+1)-dimensional BE better.

This paper provides a comprehensive bibliometricanalysis of solid-state circuit breakers, including technological developments and control methods in electric power distribution systems. By compiling and analyzing data from the Scopus database, the most cited papers in the field of protection system mechanisms can be identified. These papers, published in influential journals from various countries, covered different subject areas and case studies. Notably, 77.64 % of the articles focused on technological development and experimental control methods, while 22.35 % were review-based studies. This underscores the increasing interest among researchers in advancing the sustainability and reliability of protection devices in electric power distribution systems. The paper aims to identify and analyze the highly cited published articles on the respective field to provide future research direction on the technological development and control methods towards solid-state circuit breaker protection devices. The review also underlines numerous factors, issues, challenges, and difficulties that next-generation power semiconductor should overcome with in regards to system sustainability. Thus, this analysis will strengthen the scopes and provide context for the development of technology and control in the main protection devices in order to achieve an efficient, reliable, cost-effective, and sustainable power supply.

This study aims to investigate the properties of fractional calculus theory (FCT) in the complex domain. We focus on the relationship between the theories of special functions (SFT) and FCT, which have seen recent advancements and have led to various successful applications in fields such as engineering, mathematics, physics, biology, and other allied disciplines. Our main contribution is the development of a special function, specifically the confluent hypergeometric function (CHF) on the complex domain. By deriving various implementations of fractional order derivatives and integral operators using this function, we present a new class of special functions combining certain cases of Mittag-Leffler and confluent hypergeometric functions. Moreover, a new numerical technique for solving linear and nonlinear multi-order fractional differential equations has been developed using the proposed class of functions and the point collocation method. Graphical results are shown to demonstrate the efficacy of this proposed technique and its applicability.

This paper discusses the newly discovered acoustic waves that arise from the equilibrium between the inertia of dust particles and plasma pressure. The propagation of these waves is demonstrated to be non-linear, with supersonic solitons exhibiting either a positive or negative electrostatic potential, and linear, with normal modes in a dusty plasma. Implementing the unified method and the generalized projective Ricatti equation technique, we generate a variety of optical wave structures for the governing framework. Using $3D$ and $2D$ dimensional illustrations, the fundamental behavior of the derived solutions is visually analyzed by choosing appropriate values for arbitrary parameters that satisfy the specified constraints. The employed methodologies are acknowledged to be a powerful and effective mechanism for creating solitary wave solutions for non-linear evolution models.

The proportional hazard regression models are widely used statistical tools for analyzing survival data and estimating the effects of covariates on survival times. It is assumed that the effects of the covariates are constant across the time. In this paper, we propose a novel extension of the proportional hazard model by incorporating an exponentiated-Weibull distribution to model the baseline line hazard function. The proposed model offers more flexibility in capturing various shapes of failure rates and accommodates both monotonic and non-monotonic hazard shapes. The performance evaluation of the proposed model and comparison with other commonly used survival models including the generalized log–logistic, Weibull, Gompertz, and exponentiated exponential PH regression models are explored using simulation results. The results demonstrate the ability of the introduced model to capture the baseline hazard shapes and to estimate the effect of covariates on the hazard function accurately. Furthermore, two real survival medical data sets are analyzed to illustrate the practical importance of the proposed model to provide accurate predictions of survival outcomes for individual patients. Finally, the survival data analysis reveal that the model is a powerful tool for analyzing complex survival data.

Efficient allocation of resources is crucial in wireless ad hoc networks (WANETs) as spectrum assets are costly. Cooperative communications were introduced as a solution to the problem of limited spectrum availability. In this approach, numerous nodes share their resources and increase the bandwidth available to end-users. This research investigates the practicality of a new algorithm that optimizes resources based on load for Cooperative Communications in 5 G WANETs. The algorithm consists of two components. Initially, a distributed algorithm for forming a topology is suggested. This algorithm employs a load-based approach to explore network conditions and efficiently choose the most suitable topology. An optimization algorithm that relies on a greedy strategy is suggested. In this approach, the chosen nodes send their bits to the receiver to maximize the attainable system throughput. A thorough simulation study is conducted to evaluate the overall performance of the proposed algorithm in assessing existing methods. The proposed model obtained 94.72 % energy efficiency, 91.69 % network throughput, 94.72 % spectrum utilization, 27.47 % network delay, 24.08 % packet loss rate, 94.38 % signal-to-noise ratio, 93.91 % data transfer rate, 95.87 % error detection rate, and 94.28 % link reliability rate. The results demonstrate that the suggested algorithm significantly enhances the system and the overall network performance compared to existing approaches. The proposed approach is feasible and environmentally friendly for optimizing bandwidth in 5 G wireless ad hoc Networks.

This study takes into account the efficient estimation of the probability density function (PDF) of the Weibull-Burr XII distribution and the cumulative distribution function (CDF), which allows for greater flexibility than many other generalized distributions in use today. Nine traditional estimators are used to produce the analytical formulations for the bias and the mean squared error (MSE). A simulated investigation is conducted to evaluate the finite sample performance of the suggested estimators in terms of MSE values. In addition to that a real data application is also demonstrated for illustration.

Determining the importance of major antecedents of open innovation between such distinct partners as industry and universities influences the decision-making regarding resources and effort allocation to their improvement, according to the strategic objectives of the firms. For this purpose, the present paper proposes an approach for conducting their importance-performance analysis based on fuzzy set theory and neural networks. Considering a hierarchical component model that integrates the components of the major antecedents, this study advances a research framework that first involves the operationalization of the collected data as fuzzy numbers. Then, the SHapley Additive exPlanation-based method estimates the derived importance of each component in the hierarchical component model using an optimal two-layers back-propagation network. Finally, a nine quadrants division of the importance-performance analysis developed on the basis of relevance and determinance measures of the analyzed antecedent components, delineates the prioritization of their potential improvements. A case study aims to demonstrate the developed research framework, illustrating its effectiveness and flexibility in decision-making related to the improvement of such antecedents.